WO2020255682A1

WO2020255682A1 - Rotation detector, and motor comprising same

Info

Publication number: WO2020255682A1
Application number: PCT/JP2020/021554
Authority: WO
Inventors: 旭生揚原; 晃太来嶋
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2019-06-21
Filing date: 2020-06-01
Publication date: 2020-12-24

Abstract

A rotation detector that detects the amount of rotation of a rotating shaft in a motor, the rotation detector comprising: a magnetism-detecting element configured from a magnetic body and an inductive coil; a magnetism-shielding plate attached to the rotating shaft so as to rotate integrally, the magnetism-shielding plate having a magnetic-flux-transmitting part; and a magnet having a plurality of magnetic poles with mutually different polarities, the magnet being such that the relative position thereof with respect to the magnetism-detecting element does not change. The magnetic body exhibits a high Barkhausen effect when a magnetic field of a prescribed amount or higher is applied. When viewed from a prescribed direction, the magnetism-detecting element, the magnetism-shielding plate, and the magnet are arranged in the stated order with gaps formed between each of the magnetism-detecting element, the magnetism-shielding plate, and the magnet.

Description

Rotation detector and motor equipped with it

The present disclosure relates to a rotation detector and a motor equipped with the rotation detector.

Conventionally, an encoder has been widely used as a rotation detector for detecting the rotation speed or rotation angle of the rotation axis of a motor. Further, a servomotor that controls the drive so that the rotation speed or the rotation angle detected by the encoder approaches the target value is widely used in industrial applications.

In recent years, from the viewpoint of power saving of equipment, there is an increasing demand for driving an encoder without using an external power supply.

As a method for realizing such a so-called batteryless encoder, an encoder using a magnetic detector element having a magnetic material whose magnetization is inverted by the large Barkhausen effect has been conventionally known (for example, Patent Documents 1 to 3). See). The magnetic detector element is a sensor element in which a voltage is induced across the magnetic flux when the direction of the magnetic flux flowing inside the magnetic detector changes. The induced voltage drives the encoder.

In the conventional configuration disclosed in Patent Documents 1 to 3, the direction of the magnetic flux flowing inside the magnetic detection element is changed by rotating the magnet with respect to the fixedly arranged magnetic detection element.

However, in this case, it is necessary to devise the shape of the magnet, the number of magnetic poles, and the arrangement of the sensors added to detect the rotation direction. This has led to an increase in design cost or a decrease in design freedom.

German Patent Invention No. 10259223 Japanese Patent No. 5769879 Japanese Patent No. 5964117

This disclosure has been made in view of this point. An object of the present disclosure is to realize a rotation detector capable of detecting the amount of rotation of a rotation shaft of a motor with a simple configuration and a motor provided with the rotation detector.

In order to achieve the above object, the rotation detector according to the present disclosure is a rotation detector that detects the amount of rotation of the rotation shaft of the motor, and includes a magnetic detection element composed of a magnetic material and an induction coil, and a magnetic detection element. A magnetic material including at least a magnetic shielding plate that is integrally mounted on a rotating shaft and has a magnetic flux passing portion, and magnets that do not change their relative positions with respect to the magnetic detection element and have a plurality of magnetic poles having different polarities. When a magnetic field of more than a predetermined value is applied, a large bulkhausen effect is exhibited, and when viewed from a predetermined direction, the magnetic detection element, the magnetic shielding plate, and the magnet are spaced apart from each other, and the magnetic detection element and the magnetic shielding plate are separated from each other. , Magnets are arranged in this order.

According to this configuration, magnets and magnetic detectors can be arranged in the rotation detector without being greatly restricted, the degree of freedom in designing the rotation detector can be improved, and the design cost can be reduced.

The motor according to the present disclosure includes at least a rotor having a rotating shaft, a stator provided coaxially with the rotor and at a predetermined distance from the rotor, and a rotation detector attached to the rotating shaft. Be prepared.

According to this configuration, the design cost of the motor can be reduced. Further, the rotational state of the motor can be reliably controlled.

According to the rotation detector of the present disclosure, the degree of freedom in designing the rotation detector can be improved and the design cost can be reduced. According to the motor of the present disclosure, the design cost of the motor can be reduced.

It is sectional drawing of the motor which concerns on Embodiment 1. FIG. It is a schematic block diagram of the functional block of a signal processing circuit. It is sectional drawing of another magnetic encoder. It is a schematic diagram which shows the flow of the magnetic flux in a magnetic encoder with the rotation of a rotating shaft. It is a schematic diagram which shows the flow of the magnetic flux in a magnetic encoder with the rotation of a rotating shaft. It is a schematic diagram which shows the flow of the magnetic flux in a magnetic encoder with the rotation of a rotating shaft. It is a schematic diagram which shows the relationship between the rotation angle of a rotation shaft, and the output voltage of a magnetic detector element. It is another schematic diagram which shows the relationship between the rotation angle of a rotation shaft, and the output voltage of a magnetic detector element. It is a schematic diagram which shows the flow of the magnetic flux in the 1st magnetic encoder which concerns on modification 1. FIG. It is a schematic diagram which shows the flow of the magnetic flux in the 1st magnetic encoder which concerns on modification 1. FIG. It is a schematic diagram which shows the flow of the magnetic flux in the 1st magnetic encoder which concerns on modification 1. FIG. It is a schematic diagram which shows the flow of the magnetic flux in the 2nd magnetic encoder which concerns on modification 1. FIG. It is a schematic diagram which shows the flow of the magnetic flux in the 2nd magnetic encoder which concerns on modification 1. FIG. It is a schematic diagram which shows the flow of the magnetic flux in the 2nd magnetic encoder which concerns on modification 1. FIG. It is a schematic diagram which shows the flow of the magnetic flux in the 3rd magnetic encoder which concerns on modification 1. FIG. It is a schematic diagram which shows the flow of the magnetic flux in the 3rd magnetic encoder which concerns on modification 1. FIG. It is a schematic diagram which shows the flow of the magnetic flux in the 3rd magnetic encoder which concerns on modification 1. FIG. It is a schematic diagram which shows the arrangement relation of the magnetic shielding plate and the magnetic detection element which concerns on Embodiment 2. It is a schematic diagram which shows the arrangement relation of the magnetic shielding plate and a magnet which concerns on modification 2. It is a schematic diagram which shows the arrangement relationship of another magnetic shielding plate and magnet which concerns on modification 2. FIG. It is a schematic diagram which shows the magnetic pole arrangement of the 1st magnet which concerns on modification 3. It is a schematic diagram which shows the magnetic pole arrangement of the 2nd magnet which concerns on modification 3. It is a schematic diagram which shows the magnetic pole arrangement of the 3rd magnet which concerns on modification 3. It is a schematic diagram which looked at the magnetic encoder which concerns on modification 4 from above. It is a schematic diagram which looked at another magnetic encoder which concerns on modification 4 from above. It is a schematic diagram which looked at the magnetic encoder which concerns on Embodiment 3 from above. It is a perspective view of the magnetic encoder which concerns on Embodiment 3. It is a figure which shows the relationship between the rotation angle of a rotation shaft, and the output voltage of a magnetic detector element. It is a schematic diagram which looked at another magnetic encoder which concerns on Embodiment 3 from the top. It is a figure which shows the relationship between the rotation angle of the rotation shaft in the magnetic encoder shown in FIG. 16 and the output voltage of a magnetic detector element. It is sectional drawing of the rotary encoder which concerns on Embodiment 3. FIG. It is sectional drawing of another rotary encoder which concerns on Embodiment 3. FIG. It is a schematic diagram which looked at the 1st magnetic encoder which concerns on modification 5 from above. It is a figure which shows the relationship between the rotation angle of the rotation shaft in the magnetic encoder shown in FIG. 19 and the output voltage of a magnetic detector element. It is a schematic diagram which looked at the 2nd magnetic encoder which concerns on modification 5 from above. It is a figure which shows the relationship between the rotation angle of the rotation shaft in the magnetic encoder shown in FIG. 21 and the output voltage of a magnetic detector element. It is a schematic diagram which looked at the 3rd magnetic encoder which concerns on modification 5 from above. It is a figure which shows the relationship between the rotation angle of the rotation shaft in the magnetic encoder shown in FIG. 23, and the output voltage of a magnetic detector element. It is a schematic diagram which looked at the 4th magnetic encoder which concerns on modification 5 from above. It is a figure which shows the relationship between the rotation angle of the rotation shaft in the magnetic encoder shown in FIG. 25, and the output voltage of a magnetic detector element. It is a schematic diagram which looked at the 1st magnetic encoder which concerns on modification 6 from above. It is a figure which shows the relationship between the rotation angle of the rotation axis in the magnetic encoder shown in FIG. 27, and the output voltage of a magnetic detector element. It is a schematic diagram which looked at the 2nd magnetic encoder which concerns on modification 6 from above. It is a figure which shows the relationship between the rotation angle of the rotation shaft in the magnetic encoder shown in FIG. 29, and the output voltage of a magnetic detector element. It is a schematic diagram which looked at the 3rd magnetic encoder which concerns on modification 6 from above. It is a figure which shows the relationship between the rotation angle of the rotation shaft in the magnetic encoder shown in FIG. 31 and the output voltage of a magnetic detector element. It is a schematic diagram which looked at the magnetic encoder which concerns on modification 7 from above. It is a figure which shows the relationship between the rotation angle of the rotation shaft in the magnetic encoder shown in FIG. 33, and the output voltage of a magnetic detector element. It is a schematic diagram which looked at another magnetic encoder which concerns on modification 7 from above. It is a figure which shows the relationship between the rotation angle of the rotation shaft in the magnetic encoder shown in FIG. 35, and the output voltage of a magnetic detector element. It is a perspective view of the 1st magnetic encoder which concerns on modification 8. It is a perspective view of the 2nd magnetic encoder which concerns on modification 8. It is a perspective view of the 3rd magnetic encoder which concerns on modification 8. It is a perspective view of the 4th magnetic encoder which concerns on modification 8. FIG. 5 is a schematic view of the magnetic encoder according to the fourth embodiment as viewed from above. It is a schematic diagram which shows the operating state of the magnetic encoder shown in FIG. 41A. It is sectional drawing of the rotary encoder which concerns on Embodiment 4. FIG. It is sectional drawing of another rotary encoder which concerns on Embodiment 4. FIG. It is a schematic diagram which looked at the magnetic encoder which concerns on modification 9 from above. It is a figure which shows the relationship between the rotation angle of the rotation shaft in the magnetic encoder shown in FIG. 43, and the output voltage of a magnetic detector element. It is a schematic diagram which looked at another magnetic encoder which concerns on modification 9 from above. It is a figure which shows the relationship between the rotation angle of the rotation shaft in the magnetic encoder shown in FIG. 45, and the output voltage of a magnetic detector element. It is a schematic diagram which looked at the 1st magnetic encoder which concerns on modification 10 from above. It is a schematic diagram which shows the operating state of the magnetic encoder shown in FIG. 47A. It is a schematic diagram which looked at the 2nd magnetic encoder which concerns on modification 10 from above. It is sectional drawing of the rotary encoder which concerns on modification 10. It is sectional drawing of another rotary encoder which concerns on modification 10. It is a schematic diagram which looked at the 3rd magnetic encoder which concerns on modification 10 from above. It is a figure which shows the relationship between the rotation angle of the rotation axis in the magnetic encoder shown in FIG. 50, and the output voltage of a magnetic detector element. It is a schematic diagram which looked at the 1st magnetic encoder which concerns on modification 11 from above. It is a figure which shows the relationship between the rotation angle of the rotation shaft in the magnetic encoder shown in FIG. 52, and the output voltage of a magnetic detector element. It is a schematic diagram which looked at the 2nd magnetic encoder which concerns on modification 11 from above. It is a figure which shows the relationship between the rotation angle of the rotation shaft in the magnetic encoder shown in FIG. 54, and the output voltage of a magnetic detector element. It is a schematic diagram which looked at the 3rd magnetic encoder which concerns on modification 11 from above. It is a figure which shows the relationship between the rotation angle of the rotation shaft in the magnetic encoder shown in FIG. 56, and the output voltage of a magnetic detector element. It is a schematic diagram which looked at the 4th magnetic encoder which concerns on modification 11 from above. It is a figure which shows the relationship between the rotation angle of the rotation shaft in the magnetic encoder shown in FIG. 58, and the output voltage of a magnetic detector element. It is a schematic diagram which looked at the 5th magnetic encoder which concerns on modification 11 from above. It is a figure which shows the relationship between the rotation angle of the rotation shaft in the magnetic encoder shown in FIG. 60, and the output voltage of a magnetic detector element. It is a schematic diagram which looked at the 6th magnetic encoder which concerns on modification 11 from above. It is a figure which shows the relationship between the rotation angle of the rotation shaft in the magnetic encoder shown in FIG. 62, and the output voltage of a magnetic detector element.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The following description of preferred embodiments is merely exemplary and is not intended to limit the disclosure, its applications or its uses.

(Embodiment 1)
[Motor configuration]
FIG. 1 is a schematic cross-sectional view of the motor 300 according to the first embodiment. Note that FIG. 1 schematically illustrates the structure of the motor 300, and the actual shape and dimensions are different.

The motor 300 includes a motor case 10, a pair of

brackets

21 and 22, a rotor 30, a stator 40, a pair of

bearings

51 and 52, and a rotary encoder 100. In the following description, the radial direction of the motor case 10 is referred to as a radial direction, the circumferential direction of the motor case 10 is referred to as a circumferential direction, and the axial direction of the rotating shaft 32 provided on the rotor 30 is referred to as an axial direction. Sometimes. The radial direction of the motor case 10 is the same as the radial direction of the magnetic shielding plate 70 and the rotating plate 130. Further, in the axial direction, the side on which the rotary encoder 100 is provided may be referred to as an upper side or an upper side, and the opposite side thereof may be referred to as a lower side or a lower side. In each component or member of the motor 300, the surface at a position facing the inside of the motor case 10 may be referred to as an inner surface, and the surface at a position facing the outside of the motor case 10 may be referred to as an outer surface.

The motor case 10 is a tubular metal member with both ends open. A rotor 30, a stator 40, and a pair of

bearings

51 and 52 are housed inside the motor case 10. An elastic body such as an O-ring may be provided at the contact portion between the motor case 10 and the

brackets

21 and 22. By doing so, the airtightness inside the motor case 10 can be maintained.

The pair of

brackets

21 and 22 are flat plate-shaped metal members provided so as to cover the openings at both ends of the motor case 10, and are specifically iron members.

The rotor 30 is housed inside the motor case 10. The rotor 30 has a rotating shaft 32 at the axis of the rotor core 31. Further, a plurality of magnets (not shown) are arranged along the outer periphery of the rotor core 31. Magnets adjacent to each other have different polarities. The motor 300 is a so-called IPM (Interior Permanent Magnet) motor in which a plurality of magnets are embedded in the rotor core 31.

The rotating shaft 32 is provided so as to penetrate the bracket 21 and project to the outside of the motor case 10. A load (not shown) that is rotationally driven in accordance with the rotation of the rotating shaft 32 is connected to the portion of the rotating shaft 32 that protrudes from the bracket 21 of the rotating shaft 32.

The stator 40 is housed inside the motor case 10 and is provided on the outer side of the rotor 30 in the radial direction at a predetermined distance from the rotor 30. The stator 40 includes a yoke 41 fixed to the inner surface of the motor case 10, a plurality of salient poles (not shown) provided at predetermined intervals along the circumferential direction of the yoke 41, and a plurality of protrusions. It is composed of a plurality of coils 42 wound around each of the poles.

The pair of

bearings

51 and 52 are attached to the inner surfaces of the pair of

brackets

21 and 22, respectively, and rotatably support the rotating shaft 32.

The rotary encoder 100 is attached to a rotating shaft 32 protruding outward from the upper surface of the bracket 22. The rotary encoder 100 has an optical encoder 110 and a magnetic encoder 120. The configuration of the rotary encoder 100 will be described in detail later.

The encoder case 150 is a bottomed tubular part. The encoder case 150 is attached and fixed to the upper surface of the bracket 22 so as to surround the rotary encoder 100. In order to prevent the influence of the magnetic field from the outside of the encoder case 150, the encoder case 150 is formed of a ferromagnetic metal, for example, an iron plate material. The encoder case 150 plays a role of mechanically protecting the rotary encoder 100 and preventing liquid such as oil or water from adhering to the rotary encoder 100. A circuit board 140 supported by the encoder frame 155 is provided inside the encoder case 150. The encoder frame 155 is provided so as to surround the rotary plate 130 on the radial outer side of the rotary plate 130, which will be described later. The lower end of the encoder frame 155 is attached to the bracket 22. The circuit board 140 is attached to the upper end of the encoder frame 155.

Next, the operation of the motor 300 and its control will be described.

The plurality of coils 42 provided on the stator 40 are divided into three sets having a predetermined arrangement relationship. A three-phase current having a phase difference of 120 ° in electrical angle flows through each set of coils 42 and is excited, and a rotating magnetic field is generated in the stator 40. Torque is generated by an interaction between the rotating magnetic field and the magnetic field generated by the magnet provided in the rotor 30, and the rotating shaft 32 is supported by the

bearings

51 and 52 to rotate.

The motor control unit 310 is electrically connected to each of the rotary encoder 100 and the plurality of coils 42. The phase and the amount of current flowing through the plurality of coils 42 are corrected based on the rotation position and the amount of rotation of the rotation shaft 32 detected by the rotary encoder 100. Thereby, the rotational state of the motor 300 can be controlled to a desired state. Further, the movement amount and locus of the load (not shown) connected to the rotating shaft 32 can be controlled to a desired value.

Here, the "rotation amount" means the "rotation speed" indicating how many rotations the rotation shaft 32 has rotated, and the rotation from a predetermined origin position according to the arrangement of the magnetic detector 90 and the

magnets

80a and 80b described later. Information including the angle range in which the shaft 32 is rotated. Further, the "rotational position" means an angle at which the rotation shaft 32 is rotated from a predetermined origin position. In the present embodiment, the "rotation position" refers to the angle at which the rotation shaft 32 rotates from the origin position within one rotation. As for the information of the origin position, the information set corresponding to the reflection pattern of the optical encoder is recorded in the encoder or the control device. Further, the information on the origin position can be roughly known from the detection signal of the magnetic detector 90 provided in the magnetic encoder 120. Information set corresponding to the reflection pattern of the optical encoder is recorded in the encoder or control device.

[Structure of rotary encoder and magnetic encoder]
As shown in FIG. 1, the rotary encoder 100 includes an optical encoder 110, a magnetic encoder 120, a circuit board 140, and a signal processing circuit 200. The rotary encoder 100 is an absolute encoder that detects a rotation position or a rotation amount with reference to a determined origin position. Since the absolute encoder can identify all the rotation positions according to the resolution within one rotation, the rotation angle from the origin position can be easily detected.

The optical encoder 110 detects the rotation position of the rotation shaft 32. The optical encoder 110 may also detect the amount of rotation of the rotating shaft 32. The magnetic encoder 120 detects the amount of rotation of the rotating shaft 32 based on the detection signal of the magnetic detecting element 90. In the following description, the optical encoder 110 may be referred to as a rotation position detector 110, and the rotary encoder 100 may be referred to as a rotation detector 100.

The optical encoder 110 is a reflective encoder having a light emitting / receiving element 111, a rotating plate 130, and a slit plate 112 arranged on the upper surface of the rotating plate 130. The rotary plate 130 is rotationally and integrally attached to the rotary shaft 32. The rotary plate 130 is shared with the magnetic encoder 120. The rotating plate 130 is made of a material that allows magnetic flux to pass through, for example, a non-magnetic metal such as aluminum, a resin, or the like.

The light receiving / receiving element 111 is attached to the lower surface of the circuit board 140. The slit plate 112 is provided with a reflection pattern 112a for reflecting the light from the light receiving / receiving element 111. The reflection pattern 112a has an annular shape, and a plurality of mask patterns (not shown) for reflecting the light from the light receiving / receiving element 111 are provided along the circumferential direction. Therefore, when the light receiving / emitting element 111 emits light, the light is periodically reflected toward the light receiving / emitting element 111 according to the rotation of the rotating plate 130, and the light receiving / receiving element 111 generates a time-modulated light receiving signal. To do. By arithmetically processing the received signal by the signal processing circuit 200 attached to the circuit board 140, the rotational position of the rotating plate 130 and the rotating shaft 32 is detected.

The magnetic encoder 120 has two

magnets

80a and 80b, a magnetic shielding plate 70, and a magnetic detector 90. Further, the magnetic encoder 120 shares the rotary plate 130 with the optical encoder 110.

The two

magnets

80a and 80b are attached and fixed to the outer surface of the bracket 22 at intervals in the radial direction. The two

magnets

80a and 80b are arranged so that the directions of the magnetic poles along the circumferential direction are different from each other. Further, the two

magnets

80a and 80b are fixedly arranged near the outer periphery of the magnetic shielding plate 70 with a radial distance from the rotating shaft 32.

The magnetic shielding plate 70 is a disk-shaped member made of a material that shields magnetism such as iron. The magnetic shielding plate 70 is attached to the lower surface of the rotating plate 130 and is integrally rotated with the rotating shaft 32. Further, the magnetic shielding plate 70 is arranged at a distance in the axial direction from the

magnets

80a and 80b.

The magnetic flux passing portion 70b (see FIG. 4C) is formed in the magnetic shielding plate 70 by partially cutting out the outer peripheral portion thereof. Further, with respect to the axial direction, a magnetic flux passing portion 70a (see FIG. 4B) that penetrates the magnetic shielding plate 70 in the thickness direction, that is, in the axial direction is formed on the side opposite to the magnetic flux passing portion 70b with the rotating shaft 32 interposed therebetween. There is. When the magnetic shielding plate 70 rotates together with the rotating shaft 32 and the rotating plate 130, the magnetic

flux passing portions

70a and 70b are attached to the rotating plate 130 so that the magnetic

flux passing portions

70a and 70b pass between the

magnets

80a and 80b and the magnetic detector 90, respectively. Has been done.

The magnetic detector 90 is composed of a Wiegand wire 90a and an induction coil 90b provided around the Wiegand wire 90a. The Wiegand wire 90a is a magnetic material having different magnetic permeability between the axis and the outside. The Wiegand wire 90a exhibits a large bulkhausen effect when a magnetic field of a predetermined value or more is applied to the inside of the induction coil 90b along the longitudinal direction of the magnetic detector 90, and the magnetization direction is the longitudinal direction of the magnetic detector 90. Align to one side. Further, when the direction of the magnetic flux flowing inside the induction coil 90b changes along the longitudinal direction of the magnetic detector 90, the magnetization direction of the wigant wire 90a is dramatically reversed and a voltage pulse is induced at both ends of the induction coil 90b. It is configured to be.

The magnetic detector 90 is mounted on the circuit board 140. The magnetic detector 90 is fixedly arranged on the side opposite to the

magnets

80a and 80b with the magnetic shielding plate 70 interposed therebetween in the axial direction. The magnetic detector 90 is fixedly arranged near the outer periphery of the magnetic shielding plate 70 at a predetermined distance in the radial direction from the rotating shaft 32. The longitudinal direction of the magnetic detector 90, that is, the direction connecting one end and the other end of the magnetic detector 90 is substantially equal to the longitudinal direction of each of the

magnets

80a and 80b. The two

magnets

80a and 80b and the magnetic detector 90 are fixedly arranged, respectively. That is, the two

magnets

80a and 80b are arranged inside the encoder case 150 without changing their relative positions with respect to the magnetic detector 90.

FIG. 2 is a schematic configuration diagram of a functional block of the signal processing circuit 200. The signal processing circuit 200 calculates the rotation position and the amount of rotation of the rotation shaft 32 based on the detection signals of the optical encoder 110 and the magnetic encoder 120, respectively. The signal processing circuit 200 is attached to the upper surface of the circuit board 140, and is electrically connected to the light receiving / receiving element 111 and the magnetic detector 90.

As shown in FIG. 2, the signal processing circuit 200 receives an optical signal processing circuit 210 that receives a light receiving signal from the light receiving / receiving element 111 and performs arithmetic processing thereof, and receives a detection signal of the magnetic detection element 90 and performs arithmetic processing thereof. To process the signal output from the magnetic signal processing circuit 220, the optical signal processing circuit 210, and the signal output from the magnetic signal processing circuit 220, and output the rotation position and the amount of rotation to the outside of the signal processing circuit 200. It has an I / O unit 224 which is an interface unit of the above. In the specification of the present application, illustration and description of the internal configuration of the optical signal processing circuit 210 will be omitted.

The signal processing circuit 200 is electrically connected to a power supply 230 provided outside the rotary encoder 100. During normal operation, the driving power of each of the light receiving / receiving element 111, the optical signal processing circuit 210, and the magnetic signal processing circuit 220 is supplied from the power supply 230.

On the other hand, when power is not supplied from the power supply 230 to the signal processing circuit 200, that is, when there is no power supply, the optical signal processing circuit 210 and the light emitting / receiving element 111 do not operate. However, the magnetic signal processing circuit 220 is driven by the electric power supplied from the magnetic detector 90. That is, the magnetic encoder 120 is driven by the electric power supplied from the magnetic detector 90.

The optical signal processing circuit 210 calculates the rotation position of the rotation shaft 32 based on the light receiving signal from the light receiving / receiving element 111. The magnetic signal processing circuit 220 calculates the amount of rotation of the rotating shaft 32 based on the detection signal of the magnetic detection element 90. When the optical encoder 110 detects both the rotation position and the rotation amount of the rotation shaft 32, the optical signal processing circuit 210 may be provided with a storage unit (not shown) to store the rotation amount information. Good.

As described above, the phase and the amount of the current flowing through the motor 300 are corrected based on the rotation position and the amount of rotation of the rotation shaft 32 calculated by the signal processing circuit 200, and the rotation state of the motor 300 becomes a desired state. Be controlled.

As shown in FIG. 2, the magnetic signal processing circuit 220 has at least a voltage conversion unit 221, a signal processing unit 222, and a storage unit 223. In addition, a functional block other than these, for example, a communication unit (not shown) for exchanging data with the optical signal processing circuit 210 may be provided.

As will be described in detail later, when the magnetic flux generated by the

magnets

80a and 80b flows through the magnetic detector 90 in response to the rotation of the magnetic shield plate 70, voltage pulses are induced at both ends of the induction coil 90b of the magnetic detector 90. Will be done. The voltage pulse output from the magnetic detector 90 is input to the voltage conversion unit 221 and converted into a predetermined voltage. Specifically, each voltage pulse is rectified and then input to each capacitor (not shown) provided according to the polarity of the voltage. In this way, the electric charge is accumulated in the capacitor, and the voltage corresponding to the capacity of the capacitor is output to the next stage. The voltage conversion method is not particularly limited to this, and various methods can be applied. Further, various methods can be appropriately applied to the method for determining the polarity of the voltage pulse and the method for separating signals according to the polarity.

The output signal of the voltage conversion unit 221 is input to the signal processing unit 222, and the amount of rotation of the rotating shaft 32 is calculated according to the number of times the voltage pulse generated by the magnetic detector 90 is generated. The output signal of the signal processing unit 222 is stored in the storage unit 223. The storage unit 223 is usually composed of a non-volatile memory.

In executing the series of signal processing described above, the drive power of the signal processing unit 222 and the storage unit 223 is supplied from the voltage conversion unit 221. Specifically, the driving power source is a capacitor in which electric charges are accumulated according to the voltage pulse output from the magnetic detection element 90. That is, the magnetic encoder 120 is a battery-less encoder configured so that it can be driven without supplying power from an external power source.

The voltage conversion unit 221 and the signal processing unit 222, the storage unit 223, and the I / O unit 224 are each composed of a single electronic component or a combination of electronic components mounted on the circuit board 140, or an IC. It is composed of a combination of (integrated circuit) and / or LSI (large-scale integrated circuit).

Further, by reading out the rotation amount information stored in the storage unit 223 and synthesizing it with the rotation position information calculated by the optical encoder 110, it is possible to obtain the multi-rotation information of the rotation shaft 32. This synthesis is performed in I / O section 224. For example, assuming that the rotation position from the origin position at a certain point in time is θ and the rotation number of the rotation shaft 32 from the start of the motor 300 is n, the multi-rotation information S corresponding to the integrated rotation angle of the rotation shaft 32 is expressed by the formula. It can be expressed in the form shown in (1).

S = θ + 2πn ・・・ (1)
The multi-rotation information S may be stored in the storage unit 223. When the motor 300 is a servomotor used for the joint axis of the robot arm, the amount of movement of the tip of the robot arm can be calculated based on the multi-rotation information S. When the optical encoder 110 detects both the rotation position and the rotation amount of the rotation shaft 32, the multi-rotation information S may be calculated only from the detection result of the optical encoder 110.

The arrangement of the rotary encoder 100, particularly the magnetic encoder 120, is not particularly limited to the example shown in FIG.

FIG. 3 is a schematic cross-sectional view of another magnetic encoder. The magnetic encoder 60 shown in FIG. 3 differs from the configuration shown in FIG. 1 in the following points.

First, the magnetic shielding plate 70 is attached to the boss 160. The boss 160 is rotationally and integrally attached to the rotating shaft 32 by a screw screw (not shown). Therefore, also in this case, the magnetic shielding plate 70 rotates with the rotation of the rotating shaft 32. The magnetic detector 90 and the signal processing circuit 200 are attached to the lower surface of the circuit board 140.

Even if the magnetic encoder 60 is configured in this way, the amount of rotation can be detected as described above.

Note that the optical encoder 110 is not shown in FIG. However, for example, by attaching the rotary plate 130 in which the slit plate 112 is arranged above the magnetic shielding plate 70 to the rotary shaft 32 and attaching the light emitting / receiving element 111 to the lower surface of the circuit board 140, the optical type The encoder 110 may be configured.

[Rotary encoder rotation detection operation]
The rotation amount detection operation of the rotary encoder will be described with reference to FIGS. 4A to 5B. 4A to 4C are schematic views showing the flow of magnetic flux in the magnetic encoder as the rotation shaft rotates. FIG. 5A is a schematic diagram showing the relationship between the rotation angle of the rotation shaft and the output voltage of the magnetic detector element. FIG. 5B is another schematic view showing the relationship between the rotation angle of the rotation shaft and the output voltage of the magnetic detector.

FIG. 4A shows the internal arrangement of the magnetic encoder 60 as viewed from above. FIG. 4B shows the internal arrangement of the magnetic encoder 60 as viewed from below. FIG. 4C shows the internal arrangement when the magnetic shielding plate 70 is rotated 180 degrees from the state shown in FIG. 4B. For convenience of explanation, the drawings shown in FIGS. 4A, 4B, 4C, 5A, 5B, and the second embodiment and the first modification described below are based on the configuration of the magnetic encoder 60 shown in FIG. Shown. Further, in the magnetic encoder 60, components other than the

magnets

80a and 80b, the magnetic shielding plate 70, the magnetic detector 90, and the boss 160 are not shown.

As shown in FIGS. 4A and 4B, the magnetic shielding plate 70 rotates, and the magnetic flux passing portion 70a is between the magnet 80a and the magnetic detector 90, specifically, the magnetic flux passing portion 70a when viewed from the axial direction. Consider the case where the magnet 80a and the magnetic detector 90 move to a position where they overlap each other.

The magnetic flux passing portion 70a is provided on the outer peripheral side of the magnetic shielding plate 70, and is configured as an opening that penetrates the magnetic shielding plate 70 in the axial direction. Further, at the positions shown in FIGS. 4A and 4B, the magnet 80a is located below the magnetic flux passing portion 70a. On the other hand, the position of the magnet 80b on the magnetic shielding plate 70 is defined so that the magnet 80b is located below the magnetic shielding plate 70. Therefore, the magnetic flux generated by the magnet 80a flows from the N pole through the magnetic flux passing portion 70a inside the magnetic detection element 90 and reaches the S pole. That is, the magnetic flux flows from one end to the other end of the magnetic detector 90. Therefore, a pulsed voltage is induced across the induction coil 90b of the magnetic detector 90, and the voltage pulse generated at this time is regarded as a positive voltage pulse.

When the magnetic shield plate 70 is rotated clockwise from the positions shown in FIGS. 4A and 4B, for example, the magnetic shield plate 70 is arranged between the

magnets

80a and 80b and the magnetic detector 90. Become. As a result, the magnetic flux generated by the

magnets

80a and 80b is shielded by the magnetic shielding plate 70 and does not flow inside the magnetic detection element 90. In this case, no voltage is induced across the induction coil 90b of the magnetic detector 90.

When the magnetic shielding plate 70 further rotates in the clockwise direction, as shown in FIG. 4C, the magnetic flux passing portion 70b arranged so as to face the magnetic flux passing portion 70a in the radial direction with the rotating shaft 32 sandwiched is moved from the axial direction. Seen, it moves to a position where it overlaps with the magnet 80b and the magnetic detector 90. The magnetic flux passing portion 70b is configured as a notch formed from the outer periphery of the magnetic shielding plate 70 toward the inside. Further, at the position shown in FIG. 4C, the magnet 80b is located below the magnetic flux passing portion 70b. On the other hand, the position of the magnet 80a on the magnetic shielding plate 70 is defined so that the magnet 80a is located below the magnetic shielding plate 70.

As described above, the magnet 80a and the magnet 80b are arranged so that the directions of the magnetic poles along the circumferential direction are different from each other. Therefore, in the case shown in FIG. 4C, the magnetic flux flows from the other end to one end of the magnetic detector 90. Therefore, a voltage pulse having the opposite polarity to the voltage generated in FIG. 4B, that is, a negative voltage pulse is induced at both ends of the induction coil 90b of the magnetic detector 90.

In this way, when the magnetic shielding plate 70 rotates together with the rotating shaft 32 and the magnetic

flux passing portions

70a and 70b pass between the

magnets

80a and 80b and the magnetic detector 90, respectively, a voltage having a different polarity is applied to the magnetic detector 90. Induced. Therefore, as shown in FIG. 5A, both positive and negative voltage pulses are output from the magnetic detector 90 while the rotating shaft 32 rotates 360 degrees. In FIG. 5A, the period A corresponds to the period during which the magnetic flux passing portion 70a passes through the position shown in FIG. 4B, including the front and back. The period B corresponds to the period during which the magnetic flux passing portion 70b passes through the position shown in FIG. 4C, including the front and back. As shown in FIG. 5B, the widths t1 and t2 of the voltage pulses output from the magnetic detector 90 are derived from the magnetic detector 90 and the magnetic signal processing circuit 220, and are not so affected by the rotation speed of the magnetic shield plate 70. ..

[Effects, etc.]
As described above, the rotary encoder (rotation detector) 100 according to the present embodiment has a magnetic encoder 60 or a magnetic encoder 120. The rotary encoder 100 detects the amount of rotation of the rotation shaft 32 of the motor 300. The

magnetic encoders

60 and 120 are rotationally and integrally attached to the rotating shaft 32 and the magnetic detection element 90 composed of the Wiegand wire 90a which is a magnetic material and the induction coil 90b. The

magnetic encoders

60 and 120 include at least a magnetic shielding plate 70 having magnetic

flux passing portions

70a and 70b and two

magnets

80a and 80b.

The positions of the two

magnets

80a and 80b do not change relative to the magnetic detector 90. The two

magnets

80a and 80b have magnetic poles having different polarities from each other. That is, the two

magnets

80a and 80b have an north pole and an south pole, respectively.

The Wiegand wire 90a is configured to exhibit a large Barkhausen effect when a magnetic field of a predetermined value or higher is applied.

The magnetic detection element 90, the magnetic shielding plate 70, and the two

magnets

80a and 80b are arranged in this order with a distance from each other when viewed from a predetermined direction, in this case, an axial direction.

According to the present embodiment, a magnetic shielding plate 70 having magnetic

flux passing portions

70a and 70b and rotatably configured together with the rotating shaft 32 is provided between the

magnets

80a and 80b and the magnetic detector 90. The arrangement relationship between the

magnets

80a and 80b and the magnetic detector 90 is not greatly restricted. As a result, the degree of freedom in designing the rotary encoder 100 can be improved, and the design cost or component cost can be reduced.

Further, the

magnetic encoders

60 and 120 can be driven by the voltage induced in the magnetic detector 90. That is, the

magnetic encoders

60 and 120 can be driven even when the power supply 230 for driving the rotary encoder 100 does not supply electric power for some reason. During one rotation of the rotating shaft 32, the magnetic detector 90 generates a plurality of voltage pulses. Therefore, it is not necessary to use an expensive magnet to obtain the amount of power generation required to drive the

magnetic encoders

60 and 120. As a result, the costs of the

magnetic encoders

60 and 120, and thus the rotary encoder 100, can be reduced.

As a case where power is not supplied from the power supply 230 to the rotary encoder 100, there is a power failure or consumption of the power supply 230 when it is a battery. Even when the equipment to which the motor 300 is connected is moved, the power supply including the motor 300 is stopped, so that the power is not supplied to the rotary encoder 100.

Further, as described above, the Wiegand wire 90a exhibits a large Barkhausen effect when a magnetic field of a predetermined value or more is applied, the magnetization direction is reversed, and voltage pulses are induced at both ends of the induction coil 90b. At this time, the reversal speed in the magnetization direction depends on the magnetic properties of the Wiegand wire 90a and does not depend on the rotation speed of the rotation shaft 32.

Therefore, by configuring the magnetic detector 90 with the Wiegand wire 90a and the induction coil 90b, the magnitude of the voltage pulse generated by the magnetic detector 90 can be set to a predetermined value regardless of the rotation speed of the rotating shaft 32. can do. For example, even at a low speed rotation in which a sufficient amount of power generation cannot be obtained only by electromagnetic induction depending on the rotation speed, sufficient power can be obtained from the magnetic detector element 90 to drive the

magnetic encoders

60 and 120.

Both ends of the magnetic detector 90 are located in a plane orthogonal to the axial direction. The magnetic shielding plate 70 is a plate-shaped member located in a plane orthogonal to the axial direction. The magnetic poles of the two

magnets

80a and 80b are arranged in a plane orthogonal to the axial direction.

By doing so, the magnetic flux generated in the

magnets

80a and 80b, respectively, and upward in the axial direction passes through the magnetic

flux passing portions

70a and 70b of the magnetic shielding plate 70, and is surely inside the magnetic detection element 90. It will flow. As a result, the amount of rotation can be reliably detected, and sufficient electric power for driving the

magnetic encoders

60 and 120 can be obtained from the magnetic detector element 90.

The magnetic shielding plate 70 is a member for controlling the passage and blocking of magnetic flux generated in the

magnets

80a and 80b and flowing in the axial direction. Therefore, the magnetic shielding plate 70 does not necessarily have to be located in a plane orthogonal to the axial direction, but may be located in a plane intersecting the axial direction.

Further, when the material of the rotary plate 130 is lighter than the material used for the magnetic shield plate 70, for example, when the magnetic shield plate 70 is an iron-based material, the rotary plate 130 is an aluminum plate, so that the motor 300 Load can be reduced.

Further, when the magnetic

flux passing portions

70a and 70b move to positions where they overlap with the

magnets

80a and 80b and the magnetic detector 90 when viewed from the axial direction in accordance with the rotation of the rotating shaft 32, the magnetic

flux passing portions

70a and 70b are generated by the

magnets

80a and 80b. The magnetic flux flows to the magnetic detector 90 through the magnetic

flux passing portions

70a and 70b. In this case, a voltage is induced across the magnetic detector 90. On the other hand, when the magnetic

flux passing portions

70a and 70b are located at other positions, the magnetic flux generated by the

magnets

80a and 80b is generated because the magnetic shielding plate 70 exists between each of the

magnets

80a and 80b and the magnetic detector 90. Is shielded by the magnetic shielding plate 70 and does not reach the magnetic detection element 90, and no voltage is induced across the magnetic detection element 90.

Therefore, by monitoring the voltage generated at both ends of the magnetic detector 90 and counting the number of times the voltage pulse is generated, it is possible to detect the amount of rotation of the rotating shaft 32.

The magnetic

flux passing portions

70a and 70b are formed on the magnetic shielding plate 70 at predetermined intervals in the outer peripheral direction. When the magnetic

flux passing portions

70a and 70b adjacent to each other move to positions where they overlap each other when viewed from the axial direction with the magnetic detector 90 and the

magnets

80a and 80b, respectively, they pass through one of the magnetic flux passing portions 70a and flow to the magnetic detector 90. The direction of the magnetic flux and the direction of the magnetic flux that passes through the other magnetic flux passing portion 70b and flows to the magnetic detector 90 are different from each other.

By configuring the

magnetic encoders

60 and 120 of the rotary encoder 100 in this way, when the magnetic

flux passing portions

70a and 70b adjacent to each other pass between the magnetic detection element 90 and the

magnets

80a and 80b, respectively, they are magnetic. Voltage pulses having different polarities are generated at both ends of the detection element 90. As a result, for example, when the rotating shaft 32 continues to rotate in the clockwise direction, the amount of rotation of the rotating shaft 32 is detected based on the polarity and the number of occurrences of the voltage pulses generated at both ends of the magnetic detector 90. can do. While the rotating shaft 32 makes one rotation, the voltage is induced in the magnetic detector 90 multiple times, but it is possible to obtain sufficient power to drive the

magnetic encoders

60 and 120 with the induced voltage for one rotation. it can.

The two

magnets

80a and 80b are arranged near the outer periphery of the magnetic shielding plate 70 at predetermined intervals along the radial direction, that is, the radial direction of the magnetic shielding plate 70. The two

magnets

80a and 80b have different magnetic pole directions in the circumferential direction, that is, in the outer peripheral direction of the magnetic shielding plate 70, in the

magnets

80a and 80b adjacent to each other.

By arranging the two

magnets

80a and 80b in this way, for example, when the magnetic

flux passing portions

70a and 70b pass between the magnetic detector 90 and the

magnets

80a and 80b, respectively, the magnetic flux generated from one of the magnets is generated. Only can pass through the magnetic flux passage. Further, in the two

magnets

80a and 80b, the directions of the magnetic poles along the outer peripheral direction of the magnetic shielding plate 70 are different from each other. Therefore, when the rotating shaft 32 continues to rotate in the clockwise direction, the magnetic detector 90 The polarity of the voltage pulse generated at both ends changes periodically, and the amount of rotation of the rotating shaft 32 can be detected based on the polarity and the number of occurrences.

The magnetic

flux passing portions

70a and 70b are preferably at least one of a notch formed so as to go inward from the outer circumference of the magnetic shielding plate 70 and an opening that penetrates the magnetic shielding plate 70 in the axial direction.

By doing so, the magnetic

flux passing portions

70a and 70b can be easily formed. In addition, the magnetic flux generated by the

magnets

80a and 80b can be reliably passed through.

The rotary encoder 100 has a magnetic signal processing circuit 220. The magnetic signal processing circuit 220 includes a voltage conversion unit 221, a signal processing unit 222, a storage unit 223, and an I / O unit 224. The voltage conversion unit 221 rectifies the voltage generated across the magnetic detector 90 and converts it into a predetermined voltage. The signal processing unit 222 calculates the amount of rotation of the rotating shaft 32 according to the number of times a predetermined voltage is generated. The storage unit 223 stores the amount of rotation calculated by the signal processing unit 222. The I / O unit 224 processes the signal output from the optical signal processing circuit 210 and the signal output from the magnetic signal processing circuit 220, and outputs the rotation position and rotation amount of the signal processing circuit 200 to the outside. In this case, the driving power of the signal processing unit 222 and the storage unit 223 is supplied from the voltage conversion unit 221.

By configuring the

magnetic encoders

60 and 120 of the rotary encoder 100 in this way, the amount of rotation of the rotating shaft 32 is detected based on the voltage generated at both ends of the magnetic detector 90 in response to the rotation of the magnetic shielding plate 70. can do. Further, by storing the rotation amount, it is possible to feed back to the rotation control of the motor 300. Further, since the drive power is supplied from the voltage conversion unit 221 that converts the voltage generated at both ends of the magnetic detector 90 to the signal processing unit 222 and the storage unit 223, the power supply 230 does not supply power to the rotary encoder 100. In some cases, the

magnetic encoders

60 and 120 can be driven.

The rotary encoder 100 of the present embodiment further includes an optical encoder (optical rotation detector) 110 that detects the rotation position of the rotation shaft 32.

The rotary encoder 100 is connected to an external power supply 230. When power is supplied from the power supply 230 to the rotary encoder 100, the rotary encoder 100 detects the amount of rotation of the rotary shaft 32 and also detects the rotational position of the rotary shaft 32 by the optical encoder 110.

When power is not supplied from the power supply 230 to the rotary encoder 100, the rotary encoder 100 detects the amount of rotation of the rotary shaft 32 by supplying drive power from the voltage conversion unit 221 to the signal processing unit 222 and the storage unit 223. ..

By configuring the rotary encoder 100 in this way, it is possible to obtain multi-rotation information S regarding the rotation shaft 32. Further, the rotation state of the motor 300 can be controlled to a desired state based on the multi-rotation information S.

Further, even when power is not supplied from the power supply 230 to the rotary encoder 100, drive power is supplied from the voltage conversion unit 221 to the signal processing unit 222 and the storage unit 223 based on the voltage pulse generated by the magnetic detector 90. By doing so, the amount of rotation of the rotating shaft 32 can be detected by the

magnetic encoders

60 and 120. As a result, when the power supply is restarted, the multi-rotation information S is generated based on the rotation position detected by the optical encoder 110 and the rotation amount detected so far and stored in the storage unit 223. It can be corrected to the correct value.

As described above, the rotary encoder (rotation detector) 100 of the present embodiment is a rotation detector 100 that detects the amount of rotation of the rotation shaft 32 of the motor 300, and is guided by the wigant wire (magnetic material) 90a. The position relative to the magnetic detection element 90 composed of the coil 90b, the magnetic shielding plate 70 which is integrally mounted on the rotating shaft 32 and has the magnetic

flux passing portions

70a and 70b, and the magnetic detection element 90 does not change. The wigant wire (magnetic material) 90a exhibits a large bulkhausen effect when a magnetic field of a predetermined value or more is applied, and has at

least magnets

80a and 80b having a plurality of magnetic poles having different polarities. The magnetic detection element 90, the magnetic shielding plate 70, and the

magnets

80a and 80b are arranged in this order with the magnetic detection element 90, the magnetic shielding plate 70, and the

magnets

80a and 80b spaced apart from each other.

As a result, magnets and magnetic detectors can be arranged in the rotation detector without being greatly restricted, the degree of freedom in designing the rotation detector can be improved, and the design cost can be reduced.

The motor 300 according to the present embodiment includes a rotor 30 having a rotating shaft 32, a stator 40 provided coaxially with the rotor 30 and at a predetermined distance in the radial direction from the rotor 30, and a rotating shaft 32. At least includes a rotary encoder 100 mounted on the.

According to this embodiment, the cost of the rotary encoder 100 and thus the motor 300 can be reduced. In addition, the rotational state of the motor 300 can be reliably controlled.

<Modification example 1>
6A, 6B, and 6C are schematic views showing the flow of magnetic flux in the first magnetic encoder according to the first modification.

In explaining the drawings shown below, the same parts as those in the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted. Further, it is the same as in FIG. 3 that the components other than the magnets 81a to 83b, the magnetic shielding plate 70, the magnetic detector 90, and the boss 160 are not shown. Further, in FIGS. 6A to 8C, FIGS. 6A, 7A, and 8A show the internal arrangement of the magnetic encoder 60 as viewed from below. 6B, 7B, and 8B show the internal arrangement of the magnetic encoder 60 as viewed from above. 6C, 7C, and 8C show the internal arrangement when the magnetic shielding plate 70 is rotated 180 degrees from the state shown in FIGS. 6B, 7B, and 8B, respectively.

First, the configuration shown in FIGS. 6A, 6B, and 6C is different from the configuration shown in the first embodiment in that the magnetic

flux passing portions

70c and 70d are openings, respectively. Further, the magnetic

flux passing portions

70c and 70d are arranged asymmetrically in the radial direction with the rotating shaft 32 interposed therebetween. Specifically, the magnetic flux passing portion 70c is located closer to the rotation axis 32 than the magnetic flux passing portion 70d, and the length in the longitudinal direction thereof is longer than the length in the longitudinal direction of the magnetic flux passing portion 70d.

The two

magnets

81a and 81b are arranged at predetermined intervals along the outer peripheral direction of the magnetic shielding plate 70 when viewed from the axial direction. The polarities of the magnetic poles facing each other in the two

magnets

81a and 81b are different from each other.

As shown in FIG. 6B, when the magnetic flux passing portion 70d passes between the magnetic detection element 90 and the

magnets

81a and 81b, the magnetic flux passes from the north pole of the magnet 81b through the magnetic flux passing portion 70d and passes through the magnetic detection element 70d. It flows into one end of 90. Further, it passes through the inside of the magnetic detection element 90 and flows into the S pole of the magnet 81a from the other end of the magnetic detection element 90. On the other hand, as shown in FIG. 6C, when the magnetic flux passing portion 70c passes between the magnetic detection element 90 and the

magnets

81a and 81b, the magnetic flux passes through the magnetic flux passing portion 70c from the N pole of the magnet 81a and is magnetic. It flows into the other end of the detection element 90. Further, it passes through the inside of the magnetic detection element 90 and flows from one end of the magnetic detection element 90 into the S pole of the magnet 81b.

According to the configurations shown in FIGS. 6A, 6B, and 6C, the same effect as that of the configuration shown in the first embodiment can be obtained. Further, as compared with the configuration shown in the first embodiment, since the two

magnets

81a and 81b can be arranged at intervals, the mounting arrangement of the

magnets

81a and 81b becomes easy.

7A, 7B, and 7C are schematic views showing the flow of magnetic flux in the second magnetic encoder according to the first modification. The configuration shown in FIGS. 7A, 7B, and 7C is such that the magnetic

flux passing portions

70e, 70e, and 70f are three notches provided at predetermined intervals along the outer peripheral direction of the magnetic shielding plate 70. It is different from the configuration shown in the first embodiment. The magnetic flux passing portion 70f is formed wider in the circumferential direction than the other two magnetic flux passing portions 70e. When viewed from the axial direction, the angle formed by the center of the magnetic flux passing portion 70f and the center of one magnetic flux passing portion 70e is substantially the angle formed by the center of the magnetic flux passing portion 70f and the center of the other magnetic flux passing portion 70e. equal. The arrangement of the two

magnets

82a and 82b is the same as the configuration shown in FIGS. 6A, 6B and 6C. However, the two

magnets

82a and 82b are arranged closer to the rotation axis 32 than the positions shown in FIGS. 6A, 6B and 6C. The longitudinal direction of each of the two

magnets

82a and 82b is the radial direction. The magnetic detector 90 is also arranged closer to the rotation axis 32 than the positions shown in FIGS. 6A, 6B, and 6C.

As shown in FIG. 7B, when the two magnetic flux passing portions 70e pass through both ends of the magnetic detector 90, the magnetic flux passes from the N pole of the magnet 82a through one magnetic flux passing portion 70e and passes through the magnetic detector 90. It flows into the other end of. It passes through the inside of the magnetic detector 90, flows from one end of the magnetic detector 90, to the magnetic flux passing portion 70e of the other, and further flows into the S pole of the magnet 82b. On the other hand, as shown in FIG. 7C, when the magnetic flux passing portion 70f passes between the magnetic detection element 90 and the

magnets

82a and 82b, the magnetic flux passes from the north pole of the magnet 82b through the magnetic flux passing portion 70f and is magnetic. It flows into one end of the detection element 90. Further, it passes through the inside of the magnetic detection element 90 and flows from the other end of the magnetic detection element 90 into the S pole of the magnet 82a.

According to the configurations shown in FIGS. 7A, 7B, and 7C, the same effect as that of the configuration shown in the first embodiment can be obtained. Further, as in the configuration shown in FIGS. 6A, 6B, and 6C, the two

magnets

82a and 82b can be arranged at intervals, so that the

magnets

82a and 82b can be easily mounted and arranged.

8A, 8B, and 8C are schematic views showing the flow of magnetic flux in the third magnetic encoder according to the first modification. As shown in FIGS. 8A, 8B, and 8C, the magnetic shielding plate 70 may be provided with one magnetic flux passing portion 70g, and the magnetic detection element 90 may be arranged coaxially with the rotating shaft 32. Also in this case, when the magnetic flux passing portion 70g passes between the

magnets

83a and 83b and the magnetic detection element 90, voltage pulses are induced at both ends of the magnetic detection element 90, and the rotation shaft 32 is based on the number of occurrences. The amount of rotation can be detected.

(Embodiment 2)
FIG. 9 is a schematic view showing the arrangement relationship between the magnetic shielding plate and the magnetic detector element according to the second embodiment. For convenience of explanation, the components other than the magnetic shielding plate 70 and the magnetic detector 90 in the magnetic encoder 60 are omitted, and only a part of the magnetic detector 90 is shown.

The configuration shown in FIG. 9 is different from the configuration shown in the first embodiment in that a plurality of magnetic detector elements 90 are arranged along the outer peripheral direction of the magnetic shielding plate 70. Although not shown, two magnets are fixedly arranged on the side opposite to the magnetic detector 90 with the magnetic shielding plate 70 interposed therebetween. The arrangement of the two magnets (not shown) is the same as shown in FIG. That is, the two magnets are attached and fixed to the outer surface of the bracket 22 at intervals in the radial direction. The two magnets are arranged so that the directions of the magnetic poles along the circumferential direction are different from each other. The longitudinal direction of one magnetic detector 90 is substantially equal to the longitudinal direction of the two magnets.

Further, a plurality of magnetic

flux passing portions

70h and 70i are formed on the magnetic shielding plate 70 according to the number of magnetic detector elements 90 arranged and the arrangement interval in the circumferential direction. Of the magnetic

flux passing portions

70h and 70i adjacent to each other, one of the magnetic flux passing portions 70i is a notch formed so as to go inward from the outer circumference of the magnetic shielding plate 70. The other magnetic flux passing portion 70h is an opening formed inward in the radial direction with respect to the magnetic flux passing portion.

When the magnetic flux passing portion 70i configured as a notch passes between the magnet and the magnetic detection element 90, the magnetic flux generated by the magnet located on the outer side in the radial direction flows inside the magnetic detection element 90 to perform magnetic detection. A voltage pulse is generated across the element 90. On the other hand, when the magnetic flux passing portion 70h configured as an opening passes between the magnet and the magnetic detector 90, the magnetic flux generated by the magnet located inside in the radial direction flows inside the magnetic detector 90 and becomes magnetic. Another voltage pulse having the opposite polarity to the voltage pulse described above is generated at both ends of the detection element 90.

According to the present embodiment, the same effect as that of the configuration shown in the first embodiment can be obtained. Further, not only the amount of rotation of the rotation shaft 32 but also the change in the rotation direction can be detected based on the polarity of the voltage pulse generated by the magnetic detector 90.

When the rotation axis 32 changes the rotation direction from the clockwise direction to the counterclockwise direction, the change in the rotation direction could not be detected by only one magnetic detection element 90 included in the magnetic encoder 60. ..

On the other hand, according to the present embodiment, by arranging a plurality of magnetic detector elements 90 along the outer peripheral direction of the magnetic shielding plate 70, it is possible to detect not only the amount of rotation of the rotation shaft 32 but also the change in the rotation direction. In order to accurately determine the rotation direction, it is preferable that the magnetic detection elements 90 adjacent to each other are arranged so as to avoid positions separated by 180 degrees in the circumferential direction.

According to the present embodiment, since voltage pulses are generated in each of the plurality of magnetic detection elements 90 while the rotation shaft 32 makes one rotation, the redundancy of the detected data is ensured. Further, the stability of the electric power for driving the magnetic encoder 60 can be improved.

The magnetic encoder 60 is designed so that the number of magnetic pole sets having different polarities is larger than the number of magnetic detector elements 90.

By doing so, with respect to one magnetic detector 90, voltage pulses having different polarities can be generated during one rotation of the rotation shaft 32, and changes in the rotation direction can be easily detected.

<Modification 2>
FIG. 10A is a schematic view showing the arrangement relationship between the magnetic shielding plate and the magnet according to the second modification. FIG. 10B is a schematic view showing the arrangement relationship between the magnet and another magnetic shielding plate according to the second modification. In the magnetic encoder 60, components other than the

magnetic shielding plates

71 and 72, the

magnets

80a and 80b, and the rotating plate 130 are not shown. Only a part of the

magnets

80a and 80b is shown. The

magnets

80a and 80b are the same as those shown in FIG.

As shown in FIG. 10A, the magnetic

flux passing portions

71a and 71b are formed by forming the magnetic shielding plate 71 in an annular shape and alternately providing the portions having different inner diameters and the portions having different outer diameters. May be good. In this case, the magnetic shielding plate 71 is fixedly arranged on the surface of the rotating plate 130. The rotary plate 130 is rotationally and integrally connected to the rotary shaft 32. As the rotating plate 130 rotates together with the rotating shaft 32, the magnetic

flux passing portions

71a and 71b move so as to pass between the

magnets

80a and 80b and the magnetic detector 90, respectively. When the magnetic flux passing portion 71a passes between the

magnets

80a and 80b and the magnetic detector 90 (not shown), the magnetic flux generated by the magnet 80a is shielded by the magnetic shielding plate 71. Similarly, when the magnetic flux passing portion 71b passes between the

magnets

80a and 80b and the magnetic detector 90 (not shown), the magnetic flux generated by the magnet 80b is shielded by the magnetic shielding plate 71.

As shown in FIG. 10B, a plate material made of a quadrangular magnetic material in a plan view is attached to the rotating plate 130 at a predetermined interval in the circumferential direction to form a substantially annular magnetic shielding plate 72. You may do so. In this case, the magnetic flux passing portions 72a and 72b are configured by arranging the plate members adjacent to each other at a predetermined interval in the radial direction. The plate material made of a magnetic material may have a shape other than a quadrangle, and may be, for example, an ellipse.

When the

magnetic shielding plates

71 and 72 shown in FIGS. 10A and 10B are applied to the

magnetic encoders

60 and 120, the same effect as that of the configurations shown in the first and second embodiments can be obtained. Further, according to the present embodiment, it is possible to reduce the amount of the magnetic material used that shields the flow of the magnetic flux to the magnetic detector 90. Therefore, the cost of the magnetic encoder 120 and thus the rotary encoder 100 can be reduced.

According to this modification, the total mass of the

magnetic shielding plates

71 and 72 can be reduced as compared with the configuration shown in the first embodiment. Therefore, the load on the motor 300 can be reduced.

The magnetic shielding plate 72 shown in FIG. 10B is configured by appropriately attaching a plate material having the same shape to the rotating plate 130. Therefore, the design becomes easy. Therefore, the design man-hours and design cost of the magnetic shielding plate 72 can be reduced.

<Modification example 3>
FIG. 11A is a schematic view showing the magnetic pole arrangement of the magnet according to the modified example 3. FIG. 11B is a schematic view showing the magnetic pole arrangement of the second magnet according to the third modification. FIG. 11C is a schematic view showing the magnetic pole arrangement of the third magnet according to the third modification. For convenience of explanation, only a part of the magnetic poles is shown in FIGS. 11B and 11C, and the others are omitted.

As shown in FIG. 11A, two magnetic pole pairs of N pole and S pole may be formed on one magnet 84. For example, the two

magnets

80a and 80b shown in FIGS. 4A to 4C may be replaced with the magnet 84 shown in FIG. 11A. Further, the present invention is not limited to this, and the magnets may have a plurality of sets of magnetic poles having different polarities from each other.

Further, in FIGS. 10A and 10B, an example in which a plurality of pair of

magnets

80a and 80b are arranged along the outer peripheral direction of the magnetic shielding plate 70 is shown, but as shown in FIG. 11B, the magnets 85 are formed in an annular shape. , May be arranged coaxially with the rotating shaft 32. In this case, in the magnet 85, magnetic poles having different polarities are alternately arranged along the radial direction.

Further, as shown in FIG. 11C, the magnet 86 may be configured to further have a plurality of magnetic poles arranged along the radial direction with respect to the structure shown in FIG. 11B. In this case, the magnetic poles adjacent to each other in the radial direction are arranged so that their polarities are different from each other. The

magnets

85 and 86 are arranged coaxially with the rotating shaft 32.

Depending on the shape and arrangement of the magnetic flux passing portion formed on the magnetic shielding plate 70, magnets having the shapes shown in FIGS. 11A to 11C may be appropriately applied to the

magnetic encoders

60 and 120. In these cases as well, the same effects as those of the configurations shown in the first and second embodiments can be obtained. Further, since the number of magnets to be arranged can be reduced, the man-hours and assembly cost of the

magnetic encoders

60 and 120, and eventually the rotary encoder 100 can be reduced.

Note that magnets 84 to 86 shown in FIGS. 11A to 11C may be formed by using a plurality of magnets magnetized in a single pole. In that case, the magnets may be arranged at intervals from each other.

<Modification example 4>
FIG. 12A is a schematic view of the magnetic encoder according to the modified example 4 as viewed from above. FIG. 12B is a schematic view of another magnetic encoder according to the modified example 4 as viewed from above. For convenience of explanation, the illustration of parts other than the

magnets

80a, 80b, 86, the magnetic shielding plate 70, and the magnetic detector 90 is omitted in FIGS. 12A and 12B.

In the configuration of this modified example shown in FIGS. 12A and 12B, the north pole of the magnet 80a and the south pole of the magnet 80b, that is, magnetic poles having different polarities are arranged along the radial direction. Similarly, the south pole of the magnet 80a and the north pole of the magnet 80b are arranged along the radial direction. In the magnet 86, north poles and south poles are alternately arranged along the circumferential direction, and south poles and north poles are arranged adjacent to each other in the radial direction. Further, both ends of the magnetic detector 90 are arranged along the radial direction.

By arranging the magnetic poles of the

magnets

80a, 80b, 86 and the magnetic detector 90 in this way, it is possible to ensure that the magnetic flux flows from one end to the other end of the magnetic detector 90. This will be described further.

As described above, the magnetization direction of the Wiegand wire 90a is reversed when a magnetic field of a predetermined value or more is applied in the longitudinal direction thereof. On the other hand, in the examples shown in the first and second embodiments, the line connecting both ends of the magnetic detector 90, in other words, the longitudinal direction of the Wiegand wire 90a is arranged so as to be parallel to the tangential direction of the outer circumference of the rotating plate 130. Has been done.

In such a case, the magnetic flux generated by the magnet flows into the magnetic detector element 90 while changing its direction as the rotating shaft 32 rotates. However, depending on the size of the magnetic detector 90 or the distance between the magnetic poles, the magnetic field inside the magnetic detector 90 reverses the magnetization direction of the wigant wire 90a during the period when the magnetic flux passing portion passes below the magnetic detector 90. It may not reach the strength required to make it. In this case, the voltage pulse is not generated by the magnetic detector 90, and the rotation amount may not be detected correctly.

On the other hand, according to this modification, the longitudinal direction of the Wiegand wire 90a and the direction of the magnetic flux always generally match even during the rotation of the rotating shaft 32. As a result, during the period when the magnetic flux passing portion 70g passes below the magnetic detection element 90, the magnetization direction of the wigant wire 90a can be reliably reversed, and the magnetic detection element 90 can generate a voltage pulse. Therefore, the amount of rotation of the rotating shaft 32 can be reliably detected without missing detection.

In this modification, one magnetic detector 90 is arranged, but as shown in the second modification, a plurality of magnetic detectors 90 may be arranged. Needless to say, the arrangement, shape, and number of magnets and magnetic flux passing portions are appropriately changed accordingly.

(Embodiment 3)
FIG. 13 is a schematic view of the magnetic encoder according to the third embodiment as viewed from above. FIG. 14 is a perspective view of the magnetic encoder according to the third embodiment. FIG. 15 is a diagram showing the relationship between the rotation angle of the rotation shaft and the output voltage of the magnetic detector element.

For convenience of explanation, illustration of components other than the magnetic detector element 90, the magnetic shielding plate 73, and the

magnets

87a and 87b is omitted in FIGS. 13 to 15.

The magnetic encoder 120 shown in the present embodiment is different from the configuration shown in the first embodiment in the following points.

First, the magnetic detector 90 is arranged closer to the rotating shaft 32 (not shown) than the magnetic shielding plate 73 in the radial direction. Seen from the radial direction, the magnetic detector 90, the magnetic shielding plate 73, and the magnet 87a or the magnet 87b are arranged in this order with a distance from each other.

Next, the magnetic detector 90 is arranged so that the line connecting both ends thereof is parallel to the axial direction. Further, the two

magnets

87a and 87b are arranged 90 degrees or more apart along the circumferential direction. The south and north poles of the two

magnets

87a and 87b are arranged parallel to the axial direction. In the two

magnets

87a and 87b, the arrangement of the magnetic poles is opposite to each other. The magnetic shielding plate 73 is provided so as to surround the rotating shaft 32. The magnetic shielding plate 73 has a cylindrical shape extending in the axial direction. Since the magnetic shielding plate 73 is cut out in the axial direction, one magnetic flux passing portion 73a is provided.

The magnetic shielding plate 73 is rotationally and integrally attached to the rotating shaft 32 by a member (not shown). As shown in FIG. 14, the magnetic flux passing portion 73a passes between the magnetic detection element 90 and the

magnets

87a and 87b by rotating the magnetic shielding plate 73 with the rotation of the rotating shaft 32. And the same as shown in the second embodiment.

However, in the present embodiment, the longitudinal direction of the Wiegand wire 90a is parallel to the axial direction. The Wiegand wire 90a is magnetized by the magnetic flux flowing in this direction, and a voltage pulse is generated in the magnetic detector 90. As a result, as shown in FIG. 15, while the rotation shaft 32 makes one rotation, the magnetic detector 90 generates one positive voltage pulse and one negative voltage pulse. This is the same as shown in the first embodiment. The amount of rotation of the rotating shaft 32 is calculated by the magnetic signal processing circuit 220 based on the number of times the voltage pulse is generated, as shown in the first embodiment.

FIG. 16 is a schematic view of another magnetic encoder 120 according to the third embodiment as viewed from above. FIG. 17 is a diagram showing the relationship between the rotation angle of the rotation axis in the magnetic encoder 120 shown in FIG. 16 and the output voltage of the magnetic detector element.

The magnetic encoder 120 shown in FIG. 16 is different from the magnetic encoder 120 shown in FIGS. 13 and 14 in that two magnetic

flux passing portions

73a and 73b are formed on the magnetic shielding plate 73. The magnetic

flux passing portions

73a and 73b are provided 180 degrees apart along the circumferential direction.

The magnetic encoder 120 may be configured in this way. In this case, as shown in FIG. 17, while the rotation shaft 32 makes one rotation, the magnetic detector 90 generates a positive electrode voltage pulse and a negative electrode voltage pulse twice, respectively. As a result, the amount of rotation can be reliably detected and sufficient power can be secured to drive the magnetic encoder. Moreover, the change in the rotation direction can be detected. In addition, the degree of freedom in arranging the

magnets

87a and 87b and the magnetic detector 90 is increased. Therefore, it is possible to suppress an increase in the design cost of the rotary encoder 100.

FIG. 18A is a schematic cross-sectional view of the rotary encoder 100 according to the third embodiment. FIG. 18B is a schematic cross-sectional view of another rotary encoder 100 according to the third embodiment. When incorporating the magnetic encoder 120 shown in the present embodiment into the rotary encoder 100, a plurality of arrangements can be considered. For example, as shown in FIG. 18A, the magnetic encoder 120 may be arranged on the side close to the motor 300, and the optical encoder 110 may be arranged above the magnetic encoder 120. As shown in FIG. 18B, the optical encoder 110 may be arranged on the side close to the motor 300, and the magnetic encoder 120 may be arranged above the optical encoder 110. In the configuration shown in FIGS. 18A and 18B, the reflection pattern 112a may be arranged inside the magnetic shielding plate 73 in the radial direction. In the example shown in FIGS. 18A and 18B, the magnetic detection element 90 and the signal processing circuit 200 are electrically connected via wiring 170.

In the magnetic encoder 120 of the present embodiment, the magnetic detection element 90, the magnetic shielding plate 73, and the

magnets

87a and 87b are arranged along the radial direction. This increases the degree of freedom in arranging these parts in the radial direction. Therefore, the size of the rotary encoder 100 including the magnetic encoder 120 can be reduced in the radial direction. On the other hand, in the magnetic encoder 120 shown in the first embodiment, the magnetic detection element 90, the magnetic shielding plate 70, and the

magnets

80a and 80b are arranged along the axial direction. This increases the degree of freedom in arranging these parts in the axial direction. Therefore, it is possible to reduce the size of the rotary encoder including the magnetic encoder in the axial direction. This also applies to the case where the arrangement relationship shown in the second embodiment is applied to the magnetic encoder 120.

Depending on the type or application of the motor 300, there are multiple requests such as when the size of the rotary encoder 100 is to be reduced in the axial direction or when it is desired to be reduced in the radial direction. The rotary encoder 100 disclosed in the present specification, including the modifications shown below, can satisfy such a requirement.

<Modification 5>
FIG. 19 is a schematic view of the first magnetic encoder 120 according to the modified example 5 as viewed from above. FIG. 20 is a diagram showing the relationship between the rotation angle of the rotation axis in the magnetic encoder 120 shown in FIG. 19 and the output voltage of the magnetic detector element. FIG. 21 is a schematic view of the second magnetic encoder 120 according to the modified example 5 as viewed from above. FIG. 22 is a diagram showing the relationship between the rotation angle of the rotation axis in the magnetic encoder 120 shown in FIG. 21 and the output voltage of the magnetic detector element. In FIGS. 20 and 22, the upper graph shows the output voltage of the magnetic detector 90, and the lower graph shows the output voltage of the magnetic detector 91. FIG. 23 is a schematic view of the third magnetic encoder 120 according to the modified example 5 as viewed from above. FIG. 24 is a diagram showing the relationship between the rotation angle of the rotation axis in the magnetic encoder 120 shown in FIG. 23 and the output voltage of the magnetic detector element. FIG. 25 is a schematic view of the fourth magnetic encoder 120 according to the modified example 5 as viewed from above. FIG. 26 is a diagram showing the relationship between the rotation angle of the rotation axis in the magnetic encoder 120 shown in FIG. 25 and the output voltage of the magnetic detection element. In FIGS. 24 and 26, the upper graph shows the output voltage of the magnetic detector 90, the center graph shows the output voltage of the magnetic detector 91, and the lower graph shows the output voltage of the magnetic detector 92. For convenience of explanation, in FIGS. 19, 21, 23, and 25, the illustration of components other than the magnetic detector elements 90 to 92, the magnetic shielding plate 73, and the magnets 87a to 87f is omitted.

The configuration according to this modification is different from the configuration shown in the third embodiment in that a plurality of

magnetic detection elements

90, 91 or magnetic detection elements 90 to 92 are arranged at intervals along the circumferential direction. A pair of magnets are arranged on opposite sides of one magnetic detector element with the magnetic shielding plate 73 interposed therebetween. The two paired magnets are arranged at intervals in the circumferential direction. Therefore, in the example shown in FIGS. 19 and 21, two

magnetic detector elements

90 and 91 and four magnets 87a to 87d are arranged, and in the example shown in FIGS. 23 and 25, three magnetic detector elements 90. -92 and six magnets 87a-87f are arranged. Two paired magnets, for example,

magnets

87a and 87b, have magnetic poles arranged in opposite directions along the axial direction. In the examples shown in FIGS. 19 and 23, one magnetic flux passing portion 73a is provided on the magnetic shielding plate, and in the examples shown in FIGS. 21 and 25, two magnetic

flux passing portions

73a and 73b are provided on the magnetic shielding plate in the circumferential direction. They are provided 180 degrees apart from each other.

When the magnetic shielding plate 73 rotates and the magnetic flux passing portion passes in the vicinity of one magnetic detection element, the magnetic flux generated by one of the two paired magnets passes inside the magnetic detection element and magnetically detects. A voltage pulse is generated in the element. Further, after this, the magnetic flux generated by the other magnet passes inside the magnetic detection element, and a voltage pulse is generated in the magnetic detection element. Since the arrangement of the magnetic poles of the two magnets is opposite in the axial direction, the direction of the magnetic flux flowing through the magnetic detector is also opposite.

Therefore, in one magnetic detector element, while the rotation shaft 32 makes one rotation, a set of voltage pulses having different polarities is generated by an integral multiple of the magnetic flux passing portion.

According to this modification, not only the amount of rotation of the rotation shaft 32 but also the change in the rotation direction can be detected as shown in the modification 1. Since voltage pulses are generated in each of the plurality of magnetic detector elements 90 to 92 during one rotation of the rotation shaft 32, the redundancy of the detected data is ensured. Further, the stability of the electric power for driving the magnetic encoder 120 can be improved. Further, by increasing the number of the magnetic detector element and the magnetic flux passing portion, it is possible to obtain detailed information on the angle range in which the rotation axis is rotated from the origin position in the rotation amount. Therefore, the rotational state of the motor 300 can be controlled more precisely. When the power supply 230 for driving the rotary encoder 100 is stopped and then returned again, the multi-rotation information S can be corrected with high accuracy.

Regarding one magnetic detector element, by arranging the two magnets so that the arrangement directions of the magnetic poles are opposite to each other, voltage pulses having different polarities are sent to the magnetic detector element during one rotation of the rotating shaft 32. Can be generated. Therefore, the change in the rotation direction can be easily detected.

<Modification 6>
FIG. 27 is a schematic view of the first magnetic encoder according to the modified example 6 as viewed from above. FIG. 28 is a diagram showing the relationship between the rotation angle of the rotation axis in the magnetic encoder shown in FIG. 27 and the output voltage of the magnetic detector element. FIG. 29 is a schematic view of the second magnetic encoder according to the modified example 6 as viewed from above. FIG. 30 is a diagram showing the relationship between the rotation angle of the rotation axis in the magnetic encoder shown in FIG. 29 and the output voltage of the magnetic detector element. FIG. 31 is a schematic view of the third magnetic encoder according to the modified example 6 as viewed from above. FIG. 32 is a diagram showing the relationship between the rotation angle of the rotation axis in the magnetic encoder shown in FIG. 31 and the output voltage of the magnetic detector element. In FIGS. 30 and 32, the upper graph shows the output voltage of the magnetic detection element 90, the center graph shows the output voltage of the magnetic detection element 91, and the lower graph shows the output voltage of the magnetic detection element 92. There is. For convenience of explanation, illustration of components other than the magnetic detector elements 90 to 92, the magnetic shielding plate 74, the magnets 87a to 87c, and the magnet 87g is omitted in FIGS. 27, 29, and 31.

The configuration according to this modification is that a plurality of

magnetic shielding plates

741 and 742 are provided coaxially with the rotating shaft 32 (not shown) and at intervals in the radial direction to form the magnetic shielding plate 74. , Different from the configuration shown in the third embodiment. Since the

magnetic shielding plates

741 and 742 are rotationally and integrally attached to the rotating shaft 32, the relative positions between the magnetic

flux passing portions

741a and 742a provided respectively do not change even during the rotation of the rotating shaft 32. Further, the relative positions between the magnetic

flux passing portions

741a, 741b, 742a, and 742b do not change.

The magnetic detector elements 90 to 92 are arranged between the magnetic shield plate 741 and the magnetic shield plate 742 in the radial direction, and are arranged closer to the rotation shaft 32 than the magnetic shield plate 741. The number of magnetic detector elements is 1, 3, and 3 in the examples shown in FIGS. 27, 29, and 31, respectively. When there are a plurality of magnetic detector elements, the magnetic detector elements adjacent to each other are arranged 120 degrees apart along the circumferential direction.

In the examples shown in FIGS. 27 and 29, the magnetic

flux passing portions

741a and 742a are formed on the

magnetic shielding plates

741 and 742, respectively. The magnetic flux passing portion 741a formed on the magnetic shielding plate 741 and the magnetic flux passing portion 742a formed on the magnetic shielding plate 742 are arranged at a predetermined angle along the circumferential direction, in this case, 180 degrees apart.

In the example shown in FIG. 31, the magnetic

flux passing portions

741a and 741b are formed on the magnetic shielding plate 741, and the magnetic

flux passing portions

742a and 742b are formed on the magnetic shielding plate 742, respectively. The magnetic

flux passing portions

741a and 741b formed on the magnetic shielding plate 741 are arranged 180 degrees apart along the circumferential direction. The magnetic

flux passing portions

742a and 742b formed on the magnetic shielding plate 742 are arranged 180 degrees apart along the circumferential direction. The magnetic

flux passing portions

741a and 742a formed on the

magnetic shielding plates

741 and 742, respectively, are arranged 90 degrees apart along the circumferential direction. The magnetic

flux passing portions

741b and 742b are arranged 90 degrees apart along the circumferential direction.

Seen in the radial direction, the magnet 87g is located inside the magnetic shielding plate 142, specifically near the rotating shaft 32, and the magnets 87a to 87c are located outside the magnetic shielding plate 741. In the examples shown in FIGS. 29 and 31, the magnets 87a to 87c have magnetic poles arranged in the same direction along the axial direction.

The arrangement and number of magnets located outside the magnetic shielding plate 741 are determined according to the arrangement and number of magnetic detector elements. For example, in the example shown in FIG. 27, there is one magnetic detection element 90, and one magnet 87a is arranged on the opposite side in the radial direction with the magnetic shielding plate 741 interposed therebetween. The magnet 87a, the magnetic detector 90, and the magnet 87g are arranged in a straight line along the radial direction when viewed from above. In the example shown in FIGS. 29 and 31, magnets located on the outer side in the radial direction of the magnetic shielding plate 741 and adjacent to each other, for example,

magnets

87a and 87b, are arranged 120 degrees apart along the circumferential direction.

When one magnetic flux passing portion passes in the vicinity of one magnetic detector element with the rotation of the rotating shaft 32, the magnetic flux generated by one magnet flows inside the magnetic detector element to generate a voltage pulse. The direction of the magnetic flux passing through the magnetic flux passing portion located inside the magnetic detector element in the radial direction is opposite to the direction of the magnetic flux passing through the magnetic flux passing portion located outside. Therefore, while the rotation shaft 32 makes one rotation, voltage pulses having different polarities are generated in one magnetic detector element according to the number of magnetic flux passing portions. Specifically, when each of the

magnetic shielding plates

741 and 742 is provided with one magnetic flux passing portion, one voltage pulse having a different polarity is applied to one magnetic detector element once while the rotating shaft 32 makes one rotation. When they are generated one by one and provided at two places each, voltage pulses having different polarities are generated twice in one magnetic detector element. Further, the number of sets of voltage pulses having different polarities generated during one rotation of the rotating shaft 32 increases according to the number of magnetic detector elements or magnetic flux passing portions. For example, as shown in FIGS. 29 and 31, when there are three magnetic detector elements and a total of four magnetic flux passing portions, as shown in FIGS. 30 and 32, the polarity is polar during one rotation of the rotating shaft 32. Different voltage pulses are generated 6 times each. However, the timing at which the voltage pulse is generated differs depending on the arrangement relationship between the plurality of magnetic flux passing portions.

According to this modification, by arranging a plurality of magnetic shielding plates coaxially and arranging the magnetic detection element and the magnet accordingly, the magnetic flux surely flows inside the magnetic detection element and a voltage pulse is generated. .. In addition, the amount of rotation can be detected based on the number of times this voltage pulse is generated.

By arranging a plurality of magnetic detector elements and magnetic flux passing portions, and by defining the arrangement relationship between them as shown in this modification, it is possible to obtain the same effect as the configuration shown in modification 5. ..

<Modification 7>
FIG. 33 is a schematic view of the magnetic encoder according to the modified example 7 as viewed from above. FIG. 34 is a diagram showing the relationship between the rotation angle of the rotation axis in the magnetic encoder shown in FIG. 33 and the output voltage of the magnetic detector element. FIG. 35 is a schematic view of another magnetic encoder according to the modified example 7 as viewed from above. FIG. 36 is a diagram showing the relationship between the rotation angle of the rotation axis in the magnetic encoder shown in FIG. 35 and the output voltage of the magnetic detector element. In FIG. 34, the upper graph shows the output voltage of the magnetic detector 90, and the lower graph shows the output voltage of the magnetic detector 91. In FIG. 36, the upper graph shows the output voltage of the magnetic detector 90, the center graph shows the output voltage of the magnetic detector 91, and the lower graph shows the output voltage of the magnetic detector 92. For convenience of explanation, the drawings of components other than the magnetic detector elements 90 to 92, the magnetic shielding plate 75, the

magnets

87a and 87b, and the magnets 87h to 87k are omitted in FIGS. 33 and 35.

The configuration according to the present modification is shown in the third embodiment in that a plurality of

magnetic shielding plates

751, 752 and magnetic shielding plates 753 are provided at intervals in the axial direction to form the magnetic shielding plate 75. Different from the configuration. Since these magnetic shielding plates are rotationally and integrally attached to the rotating shaft 32, the relative positions between the magnetic flux passing portions provided in the respective rotating shafts 32 do not change even during the rotation of the rotating shaft 32. For example, in the example shown in FIG. 33, the relative positions between the magnetic

flux passing portions

751a and 752a provided on the

magnetic shielding plates

751 and 752, respectively, do not change. In the example shown in FIG. 35, the relative positions between the magnetic flux passing portions 751a to 753a provided on the magnetic shielding plates 751 to 753 do not change.

The magnetic detector element is provided for each of the plurality of magnetic shielding plates. For example, in the example shown in FIG. 33, the

magnetic detection elements

90 and 91 are provided corresponding to the

magnetic shielding plates

751 and 752, respectively. In the example shown in FIG. 35, the magnetic detector elements 90 to 92 are provided corresponding to the magnetic shielding plates 751 to 753, respectively. The magnetic detector elements 90 to 92 are arranged closer to the rotation axis 32 than the corresponding magnetic shielding plate in the radial direction.

A magnetic flux passing portion is formed at one location corresponding to each of the plurality of magnetic shielding plates. Among the plurality of magnetic shielding plates, the magnetic flux passing portions formed on the magnetic shielding plates different from each other are arranged at a predetermined angle along the circumferential direction. For example, in the example shown in FIG. 33, the magnetic

flux passing portions

751a and 752a formed on the

magnetic shielding plates

751 and 752, respectively, are arranged 90 degrees apart along the circumferential direction. In the example shown in FIG. 35, the magnetic flux passing portions 751a to 753a formed on the magnetic shielding plates 751 to 753 are arranged 60 degrees apart along the circumferential direction. Further, the magnetic detector elements 90 to 92 are arranged closer to the rotation axis 32 than the corresponding magnetic shielding plate in the radial direction.

Further, a pair of magnets are arranged at intervals from each other on the radial outer side of a plurality of magnetic shielding plates. For example, the two

magnets

87a and 87b provided on the outer side in the radial direction of the magnetic shielding plate 751 are arranged 180 degrees apart along the circumferential direction. In these two

magnets

87a and 87b, the arrangement of magnetic poles along the axial direction is opposite to each other. Such a relationship also applies to the two

magnets

87h and 87i provided on the radial outer side of the magnetic shielding plate 752 and the two

magnets

87j and 87k provided on the radial outer side of the magnetic shielding plate 753.

Furthermore, two or three magnets are arranged side by side along the axial direction. For example, in the example shown in FIG. 33, the

magnets

87a and 87h are arranged side by side along the axial direction. The

magnets

87b and 87i are arranged side by side along the axial direction. In the example shown in FIG. 35, the

magnets

87a, 87h, and 87j are arranged side by side along the axial direction.

Magnets

87b, 87i, 87k are arranged side by side along the axial direction. Magnets arranged in the axial direction have the same arrangement of magnetic poles along the axial direction.

By arranging the magnetic detector element, the magnetic shield plate, and the magnet in this way, one positive electrode and one negative electrode electric pulse are generated in one magnetic detector element while the rotation shaft 32 makes one rotation. To do. It should be noted that the timing at which the voltage pulse is generated differs depending on the arrangement relationship between the plurality of magnetic flux passing portions, as shown in the modified example 6.

According to this modification, a plurality of magnetic shielding plates are arranged side by side in the axial direction, and the magnetic detection element and the magnet are arranged accordingly. As a result, as shown in the modified example 6, the magnetic flux surely flows inside the magnetic detector element, and a voltage pulse is generated. The amount of rotation can be detected based on the number of times this voltage pulse is generated.

A plurality of magnetic detector elements and magnetic flux passing portions are arranged, and the arrangement relationship between them is specified as shown in this modification. As a result, the same effect as that of the configurations shown in the modified examples 5 and 6 can be obtained.

When the size constraint of the motor 300 is strict in the radial direction but loose in the axial direction, the rotary encoder 100 including the magnetic encoder 120 shown in this modification is used without increasing the size of the motor 300. , The above-mentioned effect can be achieved.

<Modification 8>
FIG. 37 is a perspective view of the first magnetic encoder according to the modified example 8. FIG. 38 is a perspective view of the second magnetic encoder according to the modified example 8. FIG. 39 is a perspective view of the third magnetic encoder according to the modified example 8. FIG. 40 is a perspective view of the fourth magnetic encoder according to the modified example 8. For convenience of explanation, the components other than the magnetic detector 90, the

magnetic shielding plates

73, 75, and the magnets 88a to 88f are not shown in FIGS. 37 to 40.

The magnets 87a to 87k shown in the third embodiment and the modified examples 5 to 7 each have two poles, an north pole and an south pole. The magnets 87a to 87k are rod-shaped magnets extending in the axial direction. The magnets 87a to 87k are configured so that the axial length of one magnet is substantially the same as the axial length of one magnetic detector element. However, the size and arrangement of the magnets are not particularly limited to this, and for example, the configuration shown in this modification may be used.

As shown in FIG. 37, a set of magnets shorter in the axial direction than the magnetic detector 90 is arranged in the axial direction, and magnetic flux is applied from the south pole or north pole of one magnet toward the north pole or south pole of the other magnet. May flow. A voltage pulse is generated when this magnetic flux flows inside the magnetic detector 90. By doing so, the amount of magnetic flux applied to the magnetic detector 90 can be increased. As a result, the generation and omission of the voltage pulse is reduced, and the detection reliability of the rotation amount is improved. In the example shown in FIG. 37, the set of

magnets

88a and 88c and the set of

magnets

88b and 88d apply to the above-mentioned relationship. The set of

magnets

88a and 88c is arranged 180 degrees apart from the set of

magnets

88b and 88d along the circumferential direction.

Further, magnets shorter in the axial direction than the magnetic detector element may be opposed to each other in the radial direction. For example, as shown in FIG. 38, the two

magnets

88e and 88f may face each other in the radial direction, but may be arranged at positions deviated from each other in the axial direction. By doing so, the space for arranging the magnets can be reduced, and the magnetic encoder 120 can be miniaturized. In this case, the magnetic flux generated by each of the two

magnets

88e and 88f flows inside the magnetic detector 90 through the magnetic flux passing portion 73a.

Further, the magnetic flux passing portions shown in the third embodiment and the modified examples 5 to 7 are formed by cutting out the magnetic shielding plate from the upper end to the lower end in the axial direction. However, the shape of the magnetic flux passing portion is not particularly limited to this, and may be, for example, the shape shown in this modification.

As shown in FIG. 39, the magnetic flux passing portions 73c and 73d may be formed by cutting out the magnetic shielding plate 73 halfway along the axial direction from each of the upper end and the lower end. In this case, the magnetic flux passing portions 73c and 73d are arranged apart in the axial direction. Further, as shown in FIG. 40, two

magnetic shielding plates

751 and 752 are arranged in the axial direction, and the magnetic flux passing portion 751a formed on the magnetic shielding plate 751 and the magnetic flux passing portion 752a formed on the magnetic shielding plate 752 are arranged. They may be arranged at a predetermined angle along the circumferential direction. In the example shown in FIG. 39, the arrangement and the number of magnets 88a to 88d are the same as those shown in FIG. 37. By doing so, the amount of magnetic flux applied to the magnetic detector 90 can be increased. As a result, the generation and omission of the voltage pulse is reduced, and the detection reliability of the rotation amount is improved. Further, the path of the magnetic flux flowing through the magnetic detector 90 is the same as shown in FIG. 37. Further, in the example shown in FIG. 40, the arrangement and the number of

magnets

88e and 88f are the same as those shown in FIG. 38. By doing so, the space for arranging the magnets can be reduced. Therefore, the magnetic encoder 120 can be miniaturized. The path of the magnetic flux flowing through the magnetic detector 90 is the same as shown in FIG. 38. In this case, the magnetic flux generated by one magnet flows inside one magnetic detector element through one magnetic flux passing portion. For example, the magnetic flux generated by the magnet 88f flows inside the magnetic detector 90 through the magnetic flux passing portion 751a, and a voltage pulse is generated.

(Embodiment 4)
FIG. 41A is a schematic view of the magnetic encoder 120 according to the fourth embodiment as viewed from above. FIG. 41B is a schematic diagram showing an operating state of the magnetic encoder 120 shown in FIG. 41A. For convenience of explanation, illustration of components other than the magnetic detector 90, the magnetic shielding plate 76, and the

magnets

89a and 89b is omitted in FIGS. 41A and 41B. In this embodiment and the modifications 9 to 11 described later, the magnet is arranged on the lower side in the axial direction of the magnetic detection element. Therefore, in each of the drawings shown below, the magnetic detection element is shown only by the Wiegand wire and the induction coil. To do.

The magnetic encoder 120 shown in the present embodiment is different from the magnetic encoder 120 shown in the first and third embodiments in the following points.

First, the magnetic shielding plate 76 is provided so as to surround the rotating shaft 32 in succession to the annular and plate-shaped second portion 762 located in a plane intersecting the axial direction. It has a cylindrical first portion 761 extending into. The first portion 761 extends axially from the outer peripheral edge of the second portion 762.

Magnetic

flux passing portions

761a and 762a are provided in the first and

second portions

761 and 762, respectively. In the first portion 761, the magnetic flux passing portion 761a is formed by partially cutting out from the upper end to the lower end along the axial direction. In the second portion 762, the magnetic flux passing portion 762a is formed by cutting out a portion of about 1/4 along the circumferential direction. Further, the magnetic flux passing portion 761a formed in the first portion 761 and the magnetic flux passing portion 762a formed in the second portion 762 are arranged at a predetermined angle along the circumferential direction, in this case, 180 degrees apart. Has been done.

Two rod-shaped

magnets

89a and 89b are arranged. The magnet 89a is arranged on the side opposite to the magnetic detector 90, that is, on the radial side of the magnetic shielding plate 76, with the first portion 761 interposed therebetween. The magnet 89b is arranged on the side opposite to the magnetic detection element 90, that is, on the lower side in the axial direction of the magnetic shielding plate 76, with the second portion 762 interposed therebetween. Seen from above, the magnet 89b is arranged radially inside the first portion 761. Seen from above, the two

magnets

89a and 89b are arranged so that they are parallel to each other and their magnetic poles are located in a plane orthogonal to the axial direction. However, in each magnet, the arrangement directions of the magnetic poles are opposite.

Similar to the first and second embodiments, the magnetic detector 90 is arranged at both ends in a plane orthogonal to the axial direction, and its longitudinal direction is substantially parallel to the arrangement direction of the magnetic poles of the

magnets

89a and 89b.

When the rotating shaft 32 (not shown) rotates, as shown in FIG. 41B, the magnetic flux generated by the magnet 89b passes through the magnetic flux passing portion 762a provided in the second portion 762 and is inside the magnetic detector 90. A voltage pulse is generated. At this time, the magnetic flux generated by the magnet 89a is shielded by the first portion 761 and does not reach the magnetic detection element 90. Further, when the rotating shaft 32 rotates, the magnetic flux generated by the

magnets

89a and 89b is shielded by the first portion 761 and the second portion 762, so that the magnetic flux does not flow to the magnetic detector 90 and no voltage pulse is generated. When the rotating shaft 32 further rotates, the magnetic flux generated by the magnet 89a passes through the magnetic flux passing portion 761a provided in the first portion 761 and flows inside the magnetic detector 90, and a voltage pulse is generated. .. This voltage pulse has the opposite polarity to the previously generated voltage pulse. At this time, the magnetic flux generated by the magnet 89b is shielded by the second portion 762 and does not reach the magnetic detector 90.

By repeating such an operation, a voltage pulse is periodically generated in the magnetic detector 90. The amount of rotation of the rotating shaft 32 is detected based on the number of times this voltage pulse is generated.

In the magnetic encoder 120 of the present embodiment, the magnetic detection element 90, the second portion of the magnetic shielding plate 76, and the magnet 89b are arranged at intervals along the axial direction, and the magnetic detection element 90 and the magnetism The first portion 761 of the shielding plate 76 and the magnet 89a are arranged at intervals along the radial direction.

This increases the degree of freedom in arranging these parts in the radial and axial directions. This makes it possible to reduce the size of the rotary encoder 100 including the magnetic encoder 120 in the radial direction and the axial direction. However, as compared with the magnetic encoder 120 shown in the first and second embodiments, the degree of freedom in arranging these parts in the axial direction is smaller. Compared to the magnetic encoder 120 shown in the third embodiment, the degree of freedom in arranging these parts in the radial direction is smaller.

The rotary encoder 100 including the magnetic encoder 120 of the present embodiment is useful when it is desired to reduce the size of the rotary encoder 100 to some extent in both the axial direction and the radial direction.

FIG. 42A is a schematic cross-sectional view of the rotary encoder according to the fourth embodiment. FIG. 42B is a schematic cross-sectional view of another rotary encoder according to the fourth embodiment. When incorporating the magnetic encoder 120 shown in the present embodiment into the rotary encoder 100, a plurality of arrangements can be considered. For example, as shown in FIG. 42A, the magnetic encoder 120 may be arranged on the side close to the motor 300, and the optical encoder 110 may be arranged above the magnetic encoder 120. As shown in FIG. 42B, the optical encoder 110 may be arranged on the side close to the motor 300, and the magnetic encoder 120 may be arranged above the optical encoder 110. In the configuration shown in FIGS. 42A and 42B, the reflection pattern 112a may be arranged inside the first portion 761 of the magnetic shielding plate 76 in the radial direction. In the configuration shown in FIG. 42B, the magnet 89b is arranged on the upper side in the axial direction of the magnetic shielding plate 76. The magnetic detector 90 and the signal processing circuit 200 are electrically connected via wiring 170.

<Modification 9>
FIG. 43 is a schematic view of the magnetic encoder 120 according to the modified example 9 as viewed from above. FIG. 44 is a diagram showing the relationship between the rotation angle of the rotation axis in the magnetic encoder 120 shown in FIG. 43 and the output voltage of the magnetic detector element. FIG. 45 is a schematic view of another magnetic encoder 120 according to the modified example 9 as viewed from above. FIG. 46 is a diagram showing the relationship between the rotation angle of the rotation axis in the magnetic encoder 120 shown in FIG. 45 and the output voltage of the magnetic detector element. In FIG. 44, the upper graph shows the output voltage of the magnetic detector element 90, and the lower graph shows the output voltage of the magnetic detector 91. For convenience of explanation, illustration of components other than the

magnetic detector elements

90 and 91, the magnetic shielding plate 76, and the

magnets

83a, 83b, 89a, 89b is omitted in FIGS. 43 and 45.

The magnetic encoder 120 shown in FIG. 43 is different from the encoder shown in the fourth embodiment in that two magnetic detection elements are provided. A pair of

magnets

89a and 89b are arranged for each of the

magnetic detector elements

90 and 91. One magnet 89a is arranged on the opposite side of the magnetic detector 90 with the first portion 761 interposed therebetween. The other magnet 89b is arranged on the opposite side of the magnetic detection element 90 with the second portion 762 interposed therebetween. The arrangement relationship of the

magnets

89a and 89b corresponding to the magnetic detector 91 is the same as this. Seen from above, the magnet 89b is arranged radially inside the first portion 761. When viewed from above, the two paired

magnets

The magnetic encoder 120 may be configured in this way. In this case, as shown in FIG. 44, while the rotation shaft makes one rotation, the

magnetic detectors

90 and 91 generate one positive voltage pulse and one negative voltage pulse, respectively. As a result, the amount of rotation can be reliably detected and sufficient power can be secured to drive the magnetic encoder 120. In addition, the degree of freedom in arranging the

magnets

89a and 89b and the

magnetic detectors

90 and 91 is increased. Therefore, it is possible to suppress an increase in the design cost of the rotary encoder 100.

Further, by arranging a plurality of magnetic detector elements and magnetic flux passing portions and defining the arrangement relationship between them as shown in this modification, it is possible to obtain the same effect as the configuration shown in modification 5. ..

Note that, as shown in FIG. 45, the magnetic shielding plate 73 may have a shape as shown in the third embodiment. In this case, the magnetic detector 90 is arranged near the rotating shaft 32 when viewed from the axial direction. Further, the two

magnets

83a and 83b are arranged so as to be parallel to each other and their respective magnetic poles are located in a plane orthogonal to the axial direction. However, in each magnet, the arrangement directions of the magnetic poles are opposite. Further, when viewed from above, the two

magnets

83a and 83b are arranged on the radial outer side of the magnetic shielding plate 73. In addition, they are arranged 180 degrees apart along the circumferential direction. In this case, when the magnetic flux generated by one magnet flows through the magnetic detector 90, the magnetic flux generated by the other magnet is shielded by the magnetic shielding plate 73. Therefore, as shown in FIG. 46, while the rotation shaft 32 makes one rotation, the magnetic detector 90 generates one positive electrode voltage pulse and one negative electrode voltage pulse, and based on the number of occurrences, the rotation shaft 32 occurs. The amount of rotation of is detected.

<Modification example 10>
FIG. 47A is a schematic view of the first magnetic encoder 120 according to the modified example 10 as viewed from above. FIG. 47B is a schematic diagram showing an operating state of the magnetic encoder 120 shown in FIG. 47A. FIG. 48 is a schematic view of the second magnetic encoder 120 according to the modified example 10 as viewed from above. FIG. 49A is a schematic cross-sectional view of the rotary encoder 100 according to the modified example 10. FIG. 49B is a schematic cross-sectional view of another rotary encoder 100 according to the modified example 10. FIG. 50 is a schematic view of the third magnetic encoder 120 according to the modified example 10 as viewed from above. FIG. 51 is a diagram showing the relationship between the rotation angle of the rotation axis in the magnetic encoder 120 shown in FIG. 50 and the output voltage of the magnetic detector element.

For convenience of explanation, the drawings of components other than the

magnetic detector elements

90 and 91, the magnetic shielding plate 77, and the magnets 89c to 89e are omitted in FIGS. 47A, 48, and 50. Further, in FIGS. 49A and 49B, the configuration of the magnetic encoder 120 is the same as that shown in FIG. 48.

The magnetic encoder 120 shown in this modification is different from the magnetic encoder 120 shown in the fourth embodiment and the ninth modification in the following points.

The magnetic shielding plate 77 is provided so as to surround the rotating shaft 32 in succession to the annular and plate-shaped second portion 772 located in a plane intersecting the axial direction, and extends in the axial direction. It has a cylindrical first portion 771. The first portion 771 extends axially from the inner peripheral edge of the second portion 772. The magnet 89d or the magnet 89e is arranged radially inside the first portion 771 of the magnetic shielding plate 77. The magnet 89c is arranged radially outside the first portion 771 of the magnetic shielding plate 77.

The magnetic encoder 120 may be configured in this way. In the configurations shown in FIGS. 47A and 48, the magnetic detector 90 has a positive voltage pulse and a negative electrode while the rotation shaft 32 makes one rotation. Each voltage pulse is generated once. As a result, the amount of rotation can be reliably detected and sufficient power can be secured to drive the magnetic encoder 120. In addition, the degree of freedom in arranging the magnet and the magnetic detector element is increased. Therefore, it is possible to suppress an increase in the design cost of the rotary encoder 100.

Further, as shown in FIG. 50, the two

magnetic detector elements

90 and 91 may be arranged so as to face each other in the radial direction with the first portion of the magnetic shielding plate 77 interposed therebetween. In this case, magnets 89c are arranged at intervals in the axial direction for each of the

magnetic detector elements

90 and 91.

By doing so, as shown in FIG. 51, a positive voltage pulse and a negative voltage pulse are generated once for each of the

magnetic detector elements

90 and 91 during one rotation of the rotating shaft 32. appear. As a result, the same effect as that of the configurations shown in the modified example 5 and the modified example 9 can be obtained.

Further, as shown in FIGS. 48 and 50, the magnet 89e located inside the first portion 771 in the radial direction may be an annular shape. In this case, a plurality of magnetic poles are arranged along the circumferential direction so that the polarities of the magnetic poles adjacent to each other are different. By doing so, the distance between the magnet 89e and the first portion 771 can be reduced. Therefore, the magnetic encoder 120, and thus the rotary encoder 100, can be miniaturized in the radial direction.

When incorporating the magnetic encoder 120 shown in this modification into the rotary encoder 100, a plurality of arrangements can be considered. For example, as shown in FIG. 49A, the magnetic encoder 120 may be arranged on the side close to the motor 300, and the optical encoder 110 may be arranged above the magnetic encoder 120. As shown in FIG. 49B, the optical encoder 110 may be arranged on the side close to the motor 300, and the magnetic encoder 120 may be arranged above the optical encoder 110. In the configuration shown in FIGS. 49A and 49B, the reflection pattern 112a may be arranged radially inside the first portion 771 of the magnetic shielding plate 77. The magnetic detector 90 and the signal processing circuit 200 are electrically connected via wiring 170.

<Modification 11>
FIG. 52 is a schematic view of the magnetic encoder according to the modified example 11 as viewed from above. FIG. 53 is a diagram showing the relationship between the rotation angle of the rotation axis in the magnetic encoder shown in FIG. 52 and the output voltage of the magnetic detector element. FIG. 54 is a schematic view of the second magnetic encoder according to the modified example 11 as viewed from above. FIG. 55 is a diagram showing the relationship between the rotation angle of the rotation axis in the magnetic encoder shown in FIG. 54 and the output voltage of the magnetic detector element. FIG. 56 is a schematic view of the third magnetic encoder according to the modified example 11 as viewed from above. FIG. 57 is a diagram showing the relationship between the rotation angle of the rotation axis in the magnetic encoder shown in FIG. 56 and the output voltage of the magnetic detector element. FIG. 58 is a schematic view of the fourth magnetic encoder according to the modified example 11 as viewed from above. FIG. 59 is a diagram showing the relationship between the rotation angle of the rotation axis in the magnetic encoder shown in FIG. 58 and the output voltage of the magnetic detector element. FIG. 60 is a schematic view of the fifth magnetic encoder according to the modified example 11 as viewed from above. FIG. 61 is a diagram showing the relationship between the rotation angle of the rotation axis in the magnetic encoder shown in FIG. 60 and the output voltage of the magnetic detector element. FIG. 62 is a schematic view of the sixth magnetic encoder according to the modified example 11 as viewed from above. FIG. 63 is a diagram showing the relationship between the rotation angle of the rotation axis in the magnetic encoder shown in FIG. 62 and the output voltage of the magnetic detector element. In FIGS. 53, 55, 57, 59, 61, and 63, the upper graph shows the output voltage of the magnetic detector 90, and the center graph shows the output voltage of the magnetic detector 91. The graph shows the output voltage of the magnetic detector 92, respectively. For convenience of explanation, in FIGS. 52, 54, 56, 58, 60, and 62, the components other than the magnetic detector elements 90 to 92, the

magnetic shielding plates

76, 77, and the magnets 89a to 89c, 89e are shown. Omit.

The configuration according to this modification is different from the configuration shown in the fourth embodiment and the modifications 9 and 10 in that three magnetic detector elements 90 to 92 are provided at intervals in the circumferential direction. In this modification, the magnetic detector elements adjacent to each other are arranged 120 degrees apart in the circumferential direction.

Further, in the configuration shown in FIGS. 52, 54, and 56, magnets 89a are arranged on the outer side in the radial direction with the first portion 761 of the magnetic shielding plate 76 sandwiched between one magnetic detection element. A magnet 89b is arranged on the lower side in the axial direction with the second portion 762 interposed therebetween. In the configurations shown in FIGS. 58, 60, and 62, magnets 89e are arranged radially inside one magnetic detector element with the first portion 771 of the magnetic shielding plate 77 interposed therebetween. A magnet 89c is arranged on the lower side in the axial direction with the second portion 772 interposed therebetween. The magnet 89e has an annular shape as shown in FIGS. 48 and 50, and a plurality of magnetic poles are arranged along the circumferential direction so that the polarities of the adjacent magnetic poles are different from each other.

In the configuration shown in FIGS. 52 and 58, magnetic

flux passing portions

761a and 762a are provided in the first portion 761 and the second portion 762 of the magnetic shielding plate 76, respectively, and they face each other in the radial direction when viewed from above. That is, they are arranged 180 degrees apart along the circumferential direction.

As a result, as shown in FIGS. 53 and 59, a positive electrode voltage pulse and a negative electrode voltage pulse are generated once in each of the magnetic detector elements 90 to 92 while the rotation shaft 32 makes one rotation. ..

In the configuration shown in FIG. 54, two magnetic

flux passing portions

761a and 761b are provided in the first portion 761 of the magnetic shielding plate 76. Two magnetic

flux passing portions

762a and 762b are provided in the second portion 762. Seen from above, the two magnetic

flux passing portions

761a and 761b are arranged so as to face each other in the radial direction. The two magnetic

flux passing portions

762a and 762b are arranged so as to face each other in the radial direction. The magnetic flux passing portion provided in the first portion 761 and the magnetic flux passing portion provided in the second portion 762 adjacent thereto are arranged 90 degrees apart along the circumferential direction. In the configuration shown in FIG. 60, two magnetic

flux passing portions

771a and 771b are provided in the first portion 771 of the magnetic shielding plate 77. Two magnetic

flux passing portions

772a and 772b are provided in the second portion 772. Seen from above, the two magnetic

flux passing portions

771a and 771b are arranged so as to face each other in the radial direction. The two magnetic

flux passing portions

772a and 772b are arranged so as to face each other in the radial direction. The magnetic flux passing portion provided in the first portion 771 and the magnetic flux passing portion provided in the second portion 772 adjacent thereto are arranged 90 degrees apart along the circumferential direction.

By doing so, as shown in FIGS. 55 and 61, two positive voltage pulses and two negative voltage pulses are generated in each of the magnetic detector elements 90 to 92 during one rotation of the rotating shaft 32. Occurs once.

In the configuration shown in FIG. 56, four magnetic flux passing portions 761a to 761d are provided in the first portion 761 of the magnetic shielding plate 76. The second portion 762 is provided with four magnetic flux passing portions 762a to 762d. Seen from above, the four magnetic flux passing portions 761a to 761d are arranged 90 degrees apart along the circumferential direction. The four magnetic flux passing portions 762a to 762d are arranged 90 degrees apart along the circumferential direction. Further, the magnetic flux passing portion provided in the first portion 761 and the magnetic flux passing portion provided in the second portion 762 adjacent thereto are arranged at a distance of 45 degrees along the circumferential direction. In the configuration shown in FIG. 62, four magnetic flux passing portions 771a to 771d are provided in the first portion 771 of the magnetic shielding plate 77. The second portion 772 is provided with four magnetic flux passing portions 772a to 772d. Seen from above, the four magnetic flux passing portions 771a to 771d are arranged 90 degrees apart along the circumferential direction. The four magnetic flux passing portions 772a to 772d are arranged 90 degrees apart along the circumferential direction. The magnetic flux passing portion provided in the first portion 771 and the magnetic flux passing portion provided in the second portion 772 adjacent thereto are arranged at a distance of 45 degrees along the circumferential direction.

By doing so, as shown in FIGS. 57 and 63, a positive voltage pulse and a negative voltage pulse are generated in each of the magnetic detector elements 90 to 92 during one rotation of the rotating shaft 32, respectively. Occurs 4 times each.

According to this modification, the same effect as that of the configurations shown in the fourth embodiment and the ninth and tenth modifications can be obtained. That is, the amount of rotation can be reliably detected and sufficient power can be secured to drive the magnetic encoder 120. In addition, the degree of freedom in arranging magnets and magnetic detector elements is increased. Therefore, it is possible to suppress an increase in the design cost of the rotary encoder 100.

By arranging the three magnetic detector elements 90 to 92, the same effect as that of the configuration shown in the modification 5 can be further enhanced. That is, not only the amount of rotation of the rotation shaft 32 but also the change in the rotation direction can be detected. During one rotation of the rotating shaft 32, voltage pulses are generated in each of the magnetic detector elements 90 to 92. Therefore, the redundancy of the detected data is ensured. Further, the stability of the electric power for driving the magnetic encoder 120 can be improved. Further, by increasing the number of magnetic detector elements, it is possible to obtain detailed information on the angle range in which the rotation shaft 32 is rotated from the origin position in the rotation amount. Therefore, the rotational state of the motor 300 can be controlled more precisely. Further, when the power supply 230 for driving the rotary encoder 100 is stopped and then returned again, the multi-rotation information S can be corrected with high accuracy.

Further, by increasing the number of magnetic flux passing portions, it is possible to obtain detailed information on the angle range in which the rotating shaft 32 is rotated from the origin position in the amount of rotation. Therefore, the rotational state of the motor 300 can be controlled more precisely. Further, when the power supply 230 for driving the rotary encoder 100 is stopped and then returned again, the multi-rotation information S can be corrected with high accuracy.

(Other embodiments)
It should be noted that each component shown in the first to fourth embodiments including the first to eleventh modifications can be appropriately combined to form a new embodiment.

The motor case 10 shown in FIG. 1 may have a bottomed tubular shape. In that case, for example, one of the

brackets

21 and 22 is omitted. If the bracket 22 is omitted, the rotary encoder 100 is attached to the bottom wall of the motor case 10. In this case as well, it is necessary to take measures for magnetic shielding in the encoder case 150 and the motor case 10 so that the magnetic flux from the rotor 30 and the stator 40 does not leak to the rotary encoder 100.

Although the optical encoder 110 is a reflective encoder, it may be a transmissive encoder. For example, the light receiving element may be arranged on the lower surface of the circuit board 140, the light emitting element may be arranged on the upper surface of the bracket 22, and the slit plate 112 may be provided with a transmission pattern. In this case, it is necessary not to arrange a member that blocks light, specifically, a magnetic shielding plate, between the light receiving element and the light emitting element. Further, it is necessary to make the rotating plate 130 a material that allows light from the light emitting element to be transmitted, or to remove the rotating plate 130 directly under the transmission pattern. The light emitting element may be arranged on the lower surface of the circuit board 140, and the light receiving element may be arranged on the upper surface of the bracket 22. In this case, it is necessary to electrically connect the signal processing circuit 200 and the output terminal of the light receiving element by using wiring or the like.

Further, in FIG. 1, the IPM motor has been described as an example, but it goes without saying that the rotary encoder 100 shown in the present specification can be applied to other types of motors.

Further, among the magnetic encoders 120 shown in the present specification, the combination of the magnetic detection element, the magnetic shielding plate, and the magnet can also be used as a power generation mechanism that generates electric power according to the rotation of the rotating shaft 32. As described above, when the power supply 230 for driving the rotary encoder 100 is no longer supplied with electric power for some reason, the power generation mechanism can be used as a power supply source for driving the optical encoder 110.

The rotation detector of the present disclosure can detect the amount of rotation of the rotating shaft with a simple configuration. Therefore, it is useful for application to a rotary encoder of a servo motor.

10

Motor case

21, 22 Bracket 30 Rotor 31 Rotor core 32 Rotating shaft 40 Stator 41 York 42

Coil

51, 52 Bearing 60

Magnetic encoder

70, 71, 72, 73, 74, 75, 76, 77 Magnetic shielding plate 741,742 Magnetic shielding plate (coaxial arrangement)
751, 752, 753 Magnetic shielding plate (axial arrangement)
761,771 First part of magnetic shielding plate (cylindrical part)
762,772 First part of magnetic shielding plate (plate-shaped part)
70a, 70b, 70c, 70d, 70e, 70f, 70g, 70h, 70i Magnetic

flux passing part

71a, 71b, 72a, 72b Magnetic

flux passing part

73a, 73b Magnetic

flux passing part

741a, 741b, 742a, 742b, 751a, 752a, 753a, 761a, 761b, 761c, 761d, 762a, 762b, 762c, 762d, 771a, 771b, 771c, 771d, 772a, 772b, 772c, 772d Magnetic

flux passing parts

80a, 80b, 81a, 81b, 82a, 82b, 83a, 83b, 84, 85, 86, 87a, 87b, 87c, 87d, 87e, 87h, 87i, 87j, 87k, 88a, 88b, 88c, 88e, 88f, 89a, 89b, 89c, 89d,

89e Magnet

90, 91, 92 Magnetic Detection element 90a Weigant wire (magnetic material)
90b, 91b, 92b Induction coil 100 Rotary encoder (rotation detector)
110 Optical encoder (rotational position detector)
120 Magnetic encoder 130 Rotating plate 140 Circuit board 150 Encoder case 155 Encoder frame 160 Boss 170 Wiring 200 Signal processing circuit 210 Optical signal processing circuit 220 Magnetic signal processing circuit 221 Voltage conversion unit 222 Signal processing unit 223 Storage unit 224 I / O unit 230 Power supply 300 Motor 310 Motor control unit

Claims

A rotation detector that detects the amount of rotation of the rotation shaft of a motor.
A magnetic detector composed of a magnetic material and an induction coil,
A magnetic shielding plate that is integrally mounted on the rotating shaft and has a magnetic flux passing portion,
A magnet having a plurality of magnetic poles having different polarities from each other without changing its relative position with respect to the magnetic detection element is provided at least.
The magnetic material exhibits a large Barkhausen effect when a magnetic field of a predetermined value or higher is applied.
A rotation detector in which the magnetic detector element, the magnetic shield plate, and the magnet are arranged in this order in the order of the magnetic detector element, the magnetic shield plate, and the magnet when viewed from a predetermined direction.
The rotation detector according to claim 1, wherein both ends of the magnetic detector element are located in a plane orthogonal to the axial direction which is the axial direction of the rotation axis.
The rotation detector according to claim 2, wherein the magnetic shielding plate has a plate-shaped portion located in a plane intersecting the axial direction.
The rotation detector according to claim 3, wherein the plurality of magnetic poles are arranged in a plane orthogonal to the axial direction.
The rotation detector according to claim 4, wherein at least one set of magnetic poles having different polarities among the plurality of magnetic poles are arranged along the radial direction which is the radial direction of the motor.
The rotation detector according to claim 5, wherein both ends of the magnetic detector element are arranged along the radial direction.
A plurality of the magnetic detector elements are arranged in a plane orthogonal to the axial direction.
The rotation detector according to any one of claims 3 to 6, wherein the set of magnetic poles having different polarities among the plurality of magnetic poles is larger than the number of magnetic detector elements.
The magnetic shielding plate is provided continuously with the plate-shaped portion so as to surround the rotation axis, and further has a cylindrical portion extending in the axial direction.
The magnetic flux passing portion includes a portion obtained by cutting out the cylindrical portion in the axial direction.
The magnetic flux passing portion formed in the plate-shaped portion and the magnetic flux passing portion formed in the cylindrical portion are arranged at a predetermined angle along the circumferential direction which is the outer peripheral direction of the rotation axis. Cylinder,
The magnet is
When viewed from the radial direction, which is the radial direction of the motor, one magnet arranged on the side opposite to the magnetic detector element with the magnetic shield plate interposed therebetween.
The rotation detector according to any one of claims 3 to 7, further comprising at least another magnet arranged on the side opposite to the magnetic detector element with the magnetic shield plate interposed therebetween when viewed from the axial direction.
The magnetic detector element is arranged closer to the rotation axis than the magnetic shield plate in the radial direction which is the radial direction of the motor.
The rotation detector according to claim 1, wherein the magnetic detector is arranged so that a line connecting both ends thereof is parallel to an axial direction which is an axial direction of the rotation axis.
The rotation detector according to claim 9, wherein at least one set of magnetic poles having different polarities among the plurality of magnets are arranged in parallel with the axial direction.
The magnetic shielding plate is provided so as to surround the rotation axis, and has a cylindrical shape extending in the axial direction.
The rotation detector according to claim 10, wherein the magnetic flux passing portion includes a portion of the magnetic shielding plate cut out in the axial direction.
A plurality of the magnetic shielding plates are provided coaxially with the rotation axis and at intervals in the radial direction.
The magnetic detector element is arranged on the side closer to the rotation axis than at least one of the plurality of magnetic shield plates in the radial direction.
The magnetic flux passing portion is formed in each of the plurality of magnetic shielding plates.
11. Of the plurality of magnetic shielding plates, the magnetic flux passing portions formed on different magnetic shielding plates are arranged apart by a predetermined angle along the circumferential direction which is the outer peripheral direction of the rotation axis. The rotation detector described in.
A plurality of the magnetic shielding plates are provided at intervals in the axial direction.
The magnetic detection element is provided for each of the plurality of magnetic shielding plates, and is arranged on the side closer to the rotation axis than the magnetic shielding plate in the radial direction.
The magnetic flux passing portion is formed in each of the plurality of magnetic shielding plates.
11. Of the plurality of magnetic shielding plates, the magnetic flux passing portions formed on different magnetic shielding plates are arranged apart by a predetermined angle along the circumferential direction which is the outer peripheral direction of the rotation axis. The rotation detector described in.
A plurality of the magnetic detector elements are arranged at intervals from each other.
The rotation detector according to any one of claims 9 to 13, wherein the set of magnetic poles having different polarities among the plurality of magnetic poles is larger than the number of magnetic detector elements.
When the magnetic flux passing portion moves to a position where the magnet and the magnetic detector element overlap each other when viewed from the predetermined direction in accordance with the rotation of the rotating shaft, the magnetic flux generated by the magnet is the magnetic flux passing portion. The rotation detector according to any one of claims 1 to 14, wherein a voltage pulse is generated in the magnetic detection element by flowing from one end to the other end of the magnetic detection element.
A voltage converter that rectifies the voltage pulse generated in the magnetic detector element and converts it into a predetermined voltage.
A signal processing unit that calculates the amount of rotation of the rotating shaft according to the number of times the voltage pulse is generated, and
A storage unit that stores the rotation amount calculated by the signal processing unit, and
The rotation detector according to claim 15, further comprising an I / O unit that outputs a signal corresponding to the rotation amount to the outside.
A plurality of the magnetic detector elements are provided.
The rotation detector according to claim 16, wherein the signal processing unit determines the rotation direction of the rotation axis based on the polarities of voltage pulses generated by the magnetic detection elements that are different from each other.
The rotation detector according to claim 16 or 17, further comprising an optical rotation detector for detecting the rotation position of the rotation shaft.
The rotation detector is connected to a power source and
When power is supplied from the power source to the rotation detector, the rotation detector detects the amount of rotation of the rotation shaft and the optical rotation detector detects the rotation position of the rotation shaft.
When power is not supplied from the power source to the rotation detector, the rotation detector supplies driving power from the voltage conversion unit to the signal processing unit and the storage unit, whereby the amount of rotation of the rotation shaft. The rotation detector according to claim 18.
A rotor with a rotation axis and
A stator provided coaxially with the rotor and at a predetermined distance from the rotor,
A motor including at least the rotation detector according to any one of claims 1 to 19, which is attached to the rotating shaft.