JP2001327190A - Brushless linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bushless linear motor which enables sure detection of an abnormality of a magnetic sensor by a relatively simple processing. SOLUTION: A movable element 2 has permanent magnets 21 arranged along an advancing direction so that a plurality of poles alternately become heteropolar. A stator 1 has a plurality of electromagnetics 10 opposed to the poles of the element 2 and arranged along the advancing direction of the element 2. Further, a magnetic sensor block 3 having a plurality of magnetic sensors 31 each for detecting a position of a pole of the element 2 is provided in the stator 1. A distance of the adjacent sensors 31 is set to 2L/3, where L is the distance between the adjacent poles of the magnets 21 in the advancing direction of the element 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless linear motor mainly used for electrically driving a sliding door type door body.

[0002]

2. Description of the Related Art In general, as shown in FIG. 1, a linear motor is provided with a stator 1 for generating a thrust by magnetic force between itself and a mover 2 to move the mover 2. A plurality of coils 11 arranged in the traveling direction of the child 2 are provided. An iron core 13 is inserted into each coil 11, and one end of the iron core 13 is disposed so as to face the mover 2, and the other ends of the iron cores 13 are connected to a stator yoke 14.
Are coupled magnetically. On the other hand, the mover 2 includes a permanent magnet 21 arranged such that a plurality of magnetic poles alternately become different magnetic poles in the traveling direction, and the magnetic pole of the permanent magnet 21 faces one end of the iron core 13 provided on the stator. Accordingly, a thrust by the magnetic force between the mover 2 and the stator 1 is generated. In order to generate the thrust for moving the mover 2, it is necessary to control the timing of energizing each coil 11 according to the position of the mover 2. Therefore, the magnetic sensor 31 for detecting the position of the magnetic pole of the mover 2 is required. Provided on the stator 1 side, the timing of energizing each coil 11 is controlled based on the output of the magnetic sensor 31. That is, the magnetic sensor block 3 including the plurality of magnetic sensors 31 is provided for selectively switching the coil 11 to be excited according to the position of the magnetic pole of the mover 2. By controlling the energization of each coil 11 at a timing according to the position, it becomes possible to cause the mover 2 to travel in a desired direction. Thus, the magnetic sensor 3
1 is used to switch the timing of energizing each coil 11, so that a brush is not required. That is, the linear motor shown in FIG. 1 is a brushless linear motor.

[0003]

As the magnetic sensor 31 constituting the magnetic sensor block 3, a Hall element or a Hall IC is generally used. The number of the magnetic sensors 31 is equal to the number of exciting phases of the coil 11. If an abnormality occurs even in one of the plurality of magnetic sensors 31, the correct coil 11 cannot be selected, and the movable element 2 is not moved. The vehicle cannot travel in the desired direction.

Therefore, a technique for detecting an abnormality of a magnetic sensor has been proposed (Japanese Patent Laid-Open No. Hei 5-98867). According to the technology described in this publication, the outputs of a plurality of magnetic sensors are binarized, and the order of change of the combination of outputs of the magnetic sensors is monitored. If the order of change is different from the normal case, It is considered that an abnormality has occurred in the magnetic sensor. Therefore, it can be said that the use of this technique makes it possible to detect abnormality of the magnetic sensor.

However, the technique described in the above publication detects a time change of the combination of the outputs of the magnetic sensors, and thus has a problem that relatively complicated processing is required.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a brushless linear motor capable of reliably detecting an abnormality of a magnetic sensor by relatively simple processing. is there.

[0007]

According to a first aspect of the present invention, there is provided a movable element including a permanent magnet in which a plurality of magnetic poles are alternately arranged as different magnetic poles along a traveling direction, and a magnetic pole of the movable element. A magnetic sensor comprising a plurality of coils arranged in a row along the traveling direction of the mover so as to give a thrust to the mover by an interaction between the coils, and a plurality of magnetic sensors for detecting the positions of magnetic poles of the mover A block, and a control circuit that controls the timing of energization of the coil according to the position of the magnetic pole of the mover detected by the magnetic sensor block. Each magnetic sensor is arranged so that there is no portion in which all the magnetic poles of the permanent magnet facing the magnetic sensor have the same polarity. According to this configuration, if a state equivalent to the case where all the outputs of the plurality of magnetic sensors detect the same polarity occurs, it can be regarded as abnormal, and the presence or absence of abnormality is determined only by the combination of the outputs of the magnetic sensors. Can be detected.

According to a second aspect of the present invention, there is provided a movable element having permanent magnets arranged at regular intervals so that a plurality of magnetic poles alternately become different magnetic poles along a traveling direction, and a three-phase coil and a coil inserted through the coil. A plurality of electromagnets provided with the iron cores are arranged along the moving direction of the mover, and one end of each iron core is magnetically coupled by a stator yoke, and the position of the magnetic pole of the mover is detected. A magnetic sensor block including three magnetic sensors disposed on a stator; and a control circuit for controlling timing of energizing the coil according to a position of the movable element detected by the magnetic sensor block. The moving distance of the armature in the traveling direction is longer than the entire length. In the magnetic sensor block, the distance between adjacent magnetic sensors in the moving direction of the mover is 2 / As will be doubled in which the magnetic sensors are arranged. According to this configuration, a state is used in which a magnetic sensor for detecting the magnetic pole of the mover and determining the timing of energizing the coil is used, and the outputs of the plurality of magnetic sensors provided are all equivalent to detecting the same polarity. If an error occurs, it can be regarded as an abnormality, and the presence or absence of the abnormality can be detected by a combination of the outputs of the magnetic sensors.

According to a third aspect of the present invention, in the first or second aspect of the present invention, a signal inputted to the control circuit from the magnetic sensor block is detected by a magnetic pole of each polarity of the mover for each magnetic sensor. Is a binarized output corresponding to the period during which the signal input to the control circuit is equal to the signal input to the control circuit for all magnetic sensors. It is determined that an abnormality has occurred. According to this configuration, since the signal input to the control circuit from the magnetic sensor block is binarized, abnormality of the signal input to the control circuit can be easily detected by a combination of logical values.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the control circuit stops energizing the coil when it determines that the input signal is abnormal. According to this configuration, when the abnormality of the signal input to the control circuit from the magnetic sensor block is detected, no malfunction occurs, and the mover stops automatically after traveling by inertia.

According to a fifth aspect of the present invention, in the third or fourth aspect of the present invention, the control circuit includes a display lamp for displaying that the input signal is determined to be abnormal. According to this configuration, the abnormality of the signal input from the magnetic sensor block to the control circuit can be easily known from the lighting state of the display lamp.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 and 2, a stator 1 and a mover 2 are opposed to each other, and a plurality of electromagnets 10 are arranged on the stator 1 in a row. The electromagnets 10 are arranged in a straight line in the traveling direction of the mover 2, and each electromagnet 1
Numeral 0 has a configuration in which a coil 11 is wound around a coil bobbin 12 made of a synthetic resin molded product, and an iron core 13 is inserted into a center hole of the coil bobbin 12 which opens in a circular shape. One end of the iron core 13 has a head 1 having a larger diameter than other parts.
3a, and the head 13a functions as a magnetic pole facing the mover 2. The other end of each leg 13b of each iron core 13 is inserted into a hole (not shown) provided in a stator yoke 14 made of a soft magnetic material, and is mechanically and magnetically coupled by caulking or the like.

On the other hand, the mover 2 has a permanent magnet 21 in which different magnetic poles are alternately arranged in the traveling direction. The permanent magnet 21 is arranged so that one surface in the thickness direction faces the head 13 a of the iron core 13, and the mover yoke 22 is superimposed on the other surface in the thickness direction of the permanent magnet 21. The mover yoke 22 is provided to suppress the leakage of the magnetic flux to the other surface side of the permanent magnet 21 and increase the magnetic efficiency. The permanent magnet 21 may have a shape in which a plurality of permanent magnets are arranged.
The permanent magnets 21 are formed by magnetizing the magnetic plates in multiple poles along the longitudinal direction. The magnetic poles of the permanent magnet 21 are formed at an equal pitch. In this embodiment, when the pitch between the magnetic poles of the permanent magnet 21 is L, the stator 1
Is set so that the distance between adjacent iron cores 13 becomes 10 L / 6. The movable range of the mover 2 is larger than the entire length in the traveling direction.

The stator 1 is also provided with a magnetic sensor block 3. The magnetic sensor block 3 includes three magnetic sensors 31 each composed of a one-side magnetic field type Hall IC for detecting the position of the magnetic pole of the permanent magnet 21 provided on the mover 2, and as shown in FIG. Output of 3 to control circuit 4
2 so that the control circuit 42
The timing of energization of the stator 1 is controlled so that a magnetic force acts between the mover 2 and the stator 1 (that is, the coil 11
The mover 2 receives a thrust (by interaction between the mover 2 and the magnetic pole of the mover 2). The Hall IC includes a Hall element and integrates a circuit unit for binarizing an analog output from the Hall element into an H level and an L level in accordance with switching of the magnetic pole of the permanent magnet 21. Here, the one-sided magnetic field type Hall IC means that when the magnetic flux density becomes equal to or more than a predetermined value with respect to only one of the N pole and the S pole.
This means that the value output is inverted. For example, S
If the change in magnetic flux density at the pole is binarized, the output value is not changed at the N pole even if the magnetic flux density changes. Magnetic sensor block 3 is 3
The magnetic sensors 31 are mounted on a printed circuit board 32, which is disposed between the two electromagnets 10 near the center in the longitudinal direction of the stator 1, and via a fixing spacer 33. The magnetic sensors 31 are fixed to the stator yoke 14 with screws or the like, and are disposed such that the tip end surfaces of the magnetic sensors 31 are located substantially on the same plane as the head 13 a of the iron core 13. Here, the interval between the two electromagnets 10 is set to 22L / 6, and the interval between the magnetic sensors 31 in the magnetic sensor block 3 is set to 2L / 3. Also, in FIG. 2, the center magnetic sensor 31 is 1
It is arranged so as to have an interval of 2 L / 6 and 10 L / 6 with respect to the right electromagnet 10. Note that a Hall element may be used as the magnetic sensor 31, and a circuit for binarizing the output of the Hall element may be mounted on the printed circuit board 32.

In the present embodiment, a three-phase coil 11 connected so as to form a Y connection is provided, and is controlled so as to apply a thrust to the mover 2 by exciting each of the two phases. A circuit for controlling the energization of each coil 11 based on the output of the magnetic sensor 31 is configured as shown in FIG. The coils 11 are provided in three phases as described above.
One end of each 1 is connected in common to form a Y connection.
Therefore, the coil block 30 including the three-phase coils 11 has three terminals. On the other hand, a circuit for controlling the energization of the coil 11 includes two switching elements Q11, Q12, Q2 each connected between both ends of the DC power supply 41.
1, three series circuits of Q22, Q31, and Q32 are provided.
Each terminal of the coil block 30 is connected to an intermediate point of each series circuit, that is, a connection point of the switching elements Q11 and Q12, a connection point of the switching elements Q21 and Q22, and a connection point of the switching elements Q31 and Q32. You. In addition, each switching element Q11, Q12, Q
21, Q22, Q31, and Q32 have circulating diodes D11, D12, D21, D22, D31,
D32 is connected in anti-parallel. Here, the anti-parallel to the switching elements Q11, Q12, Q21, Q22, Q31, Q32 means that the switching elements Q11, Q12,
Q21, Q22, Q31, Q32, and switching elements Q11, Q12, Q21, Q22, Q
31 and Q32 have a polarity in which a current flows in a direction opposite to that in the ON state.

Each of the switching elements Q11 and Q1 described above
2, Q21, Q22, Q31, Q32 are magnetic sensors 31
Are turned on and off by the connected control circuit 42. The control circuit 42 includes a microcomputer as a main component, and controls the switching elements Q11, Q11 according to a preset program.
Q12, Q21, Q22, Q31, and Q32 are controlled according to the output of the magnetic sensor 31.

The coil 11 having one end connected to the connection point of the switching elements Q11 and Q12 is U-phase, the coil 11 having one end connected to the connection point of the switching elements Q21 and Q22 is V-phase, and the switching elements Q31 and Q32 If the coil 11 whose one end is connected to the connection point is defined as a W-phase, the control circuit 32 controls the U-phase and V-phase coils 11, the V-phase and W-phase coils 11, and the W-phase and U-phase coils. Switching elements Q11, Q12, Q2 so that
1, Q22, Q31, and Q32 are controlled on and off. For example, a state where the switching elements Q11 and Q22 are turned on, a state where the switching elements Q21 and Q32 are turned on, and a state where the switching elements Q31 and Q12 are turned on are cyclically repeated. When the moving direction of the mover 2 is reversed, the switching elements Q21, Q1
2, the switching elements Q11, Q32
Are turned on and the states of turning on the switching elements Q31 and Q22 are cyclically repeated. The control circuit 32 has a microcomputer as a main component, and switches the switching elements Q11, Q12, Q21, Q22, Q31, Q3 based on the position of the mover 2 detected by the magnetic sensor 31 as described above.
2 is turned on and off. In this way, by sequentially exciting the coils 11 for each of the two phases, it is possible to give the mover 2 a thrust that travels substantially straight.

In FIG. 2, reference numerals U, V, and W indicate phases of each coil 11. Each coil 11 having an apostrophe added to these codes has an excitation polarity that is the same as that of the coil 11 having no apostrophe. Means that the opposite is true. In the illustrated example, U, V ', W, U', V, W '
The coils 11 of each phase are arranged in this order. However, as described above, the switching element Q1 is controlled by the control circuit 32.
1, Q12, Q21, Q22, Q31, Q32 are turned on and off cyclically (that is, U, V → V, W → W, U
2) The two-phase coils 11 that are energized at the same time are excited with opposite polarities. Therefore, when two adjacent coils 11 are excited in FIG. One coil 11 between each two coils 11 is not excited. In addition, the two coils 11 that are simultaneously excited are excited to have the same polarity. For example, in the coil 11 of U,
Assuming that the head 13a of No. 3 is excited so as to have an N pole, the coil 11 of U 'is an S pole, the coil 11 of V is an S pole,
The coil 11 of V 'becomes an N pole. That is, at this time, the N pole, the N pole, the non-excitation, the S pole, the S pole, and the non-excitation are performed. In the magnetic sensor block 3, the rightmost magnetic sensor 31 corresponds to the U phase, the central magnetic sensor 31 corresponds to the W phase, and the leftmost magnetic sensor 31 corresponds to the V phase.

When a normal output is obtained from the magnetic sensor 31, as shown in FIG.
, Each magnetic sensor 31 generates a binary output. As is clear from the figure, three magnetic sensors 3
1 are not simultaneously at H level or L level (the upper side indicates H level in the figure), and the output value of at least one magnetic sensor 31 is different from the output value of another magnetic sensor 31. Will be different.

On the other hand, if the U-phase magnetic sensor 31 fails and the output goes low, or if the U-phase magnetic sensor 31 is disconnected from the control circuit 42, as shown in FIG.
The input to the control circuit 42 is always at the L level. In this case, all the outputs of the three magnetic sensors 31 (the control circuit 4
2) have the same value (L level in the illustrated example). In FIG. 5, at the position indicated by P, the outputs of all the magnetic sensors 31 are at the L level.
Here, only the U-phase magnetic sensor 31 is described, but the same applies to the V-phase magnetic sensor 31 or the W-phase magnetic sensor 31.

As is clear from the relationship between FIG. 4 and FIG.
If a period occurs in which all the inputs from the magnetic sensor 31 to the control circuit 42 have the same value, an abnormality in the magnetic sensor 31 or the magnetic sensor 31 and the control circuit 4
2 can be regarded as an abnormality, and the presence or absence of an abnormality can be determined by detecting such a state. Therefore, if the subroutine shown in FIG. 6 is incorporated in a part of the speed control program for determining the traveling speed of the mover 2 and this subroutine is executed periodically during execution of the speed control program, It is possible to detect the presence or absence of an abnormality, and to control the movable element 2 to stop if the magnetic sensor 31 has an abnormality. That is, by considering the traveling speed of the mover 2, a subroutine is called from the main routine at a timing immediately before the change point of the output of the magnetic sensor 31, and the inputs from the magnetic sensor 31 to the control circuit 42 all have the same value. It is checked whether or not it is (S1). If the values are not the same, the process returns to the main routine (S
2) If the values are the same, all the switching elements Q11, Q12, Q21, Q22, Q31, Q32 are turned off to stop the movement of the mover 2 (S3), and the light emitting diode is formed. An abnormality is reported by turning on a display lamp (magnetic sensor abnormality lamp) not shown (S4). By providing such a subroutine, the magnetic sensor 3 at the position P in FIG.
1 can be detected. Note that if the control circuit 42 is operated even when the mover 2 is not running, it is possible to detect the presence or absence of an abnormality in the magnetic sensor 31 even when the mover 2 is moved manually. Here, the display lamp may be configured to change colors between normal and abnormal times, or to switch between continuous lighting and blinking lighting. Further, a display lamp that lights up in a normal state and a display lamp that lights up abnormally may be provided, or a plurality of display lamps that turn on in an abnormal state may be provided.

[0022]

According to the first aspect of the present invention, there is provided a movable element including permanent magnets in which a plurality of magnetic poles are alternately arranged in the traveling direction so as to be different magnetic poles, and a magnetic pole of the movable element. A magnetic sensor block comprising a plurality of coils arranged in the moving direction of the mover so as to apply a thrust to the mover by an action, and a plurality of magnetic sensors for detecting the positions of magnetic poles of the mover; A control circuit for controlling the timing of energizing the coil according to the position of the magnetic pole of the mover detected by the sensor block, wherein the magnetic sensor block faces each magnetic sensor in the entire section in which the mover travels. Each magnetic sensor is arranged so that there is no part where the magnetic poles of the permanent magnets all have the same polarity,
An abnormality can be regarded as an abnormality if a state equivalent to all the outputs of multiple magnetic sensors detecting the same polarity occurs, and the presence / absence of an abnormality can be detected relatively easily only by combining the outputs of the magnetic sensors. There is an advantage that it becomes possible.

According to a second aspect of the present invention, there is provided a movable element having permanent magnets arranged at regular intervals so that a plurality of magnetic poles alternately become different magnetic poles along the traveling direction, and a three-phase coil and a coil inserted through the coil. A plurality of electromagnets provided with the iron cores are arranged along the moving direction of the mover, and one end of each iron core is magnetically coupled by a stator yoke, and the position of the magnetic pole of the mover is detected. A magnetic sensor block including three magnetic sensors disposed on a stator; and a control circuit for controlling timing of energizing the coil according to a position of the movable element detected by the magnetic sensor block. The moving distance of the armature in the traveling direction is longer than the entire length. In the magnetic sensor block, the distance between adjacent magnetic sensors in the moving direction of the mover is 2 / Each magnetic sensor is arranged so as to be twice as large, and a magnetic sensor for detecting the magnetic pole of the mover to determine the timing of energizing the coil is used. If a state equivalent to the detection of the polarity occurs, it can be regarded as an abnormality, and there is an advantage that the presence or absence of the abnormality can be relatively easily detected only by a combination of the outputs of the magnetic sensors. .

According to a third aspect of the present invention, in the first or the second aspect of the present invention, a signal input from the magnetic sensor block to the control circuit detects a magnetic pole of each polarity of the mover for each magnetic sensor. Is a binarized output corresponding to the period during which the signal input to the control circuit is equal to the signal input to the control circuit for all magnetic sensors. Since the signal input from the magnetic sensor block to the control circuit is binarized, it is easy to detect the abnormality of the signal input to the control circuit by a combination of logical values. There is an advantage that can be.

According to a fourth aspect of the present invention, in the third aspect of the invention, the control circuit stops energizing the coil when it determines that the input signal is abnormal. There is an advantage that no malfunction occurs when an abnormality of a signal input to the control circuit is detected, and the mover stops automatically after traveling by inertia.

According to a fifth aspect of the present invention, in the third or fourth aspect of the present invention, the control circuit includes a display lamp for displaying that the input signal is determined to be abnormal. There is an advantage that the abnormality of the signal input from the sensor block to the control circuit can be easily known from the lighting state of the display lamp.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an overall configuration of an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a main part of the above.

FIG. 3 is a circuit diagram of the same.

FIG. 4 is an operation explanatory diagram showing an output signal of the magnetic sensor block according to the first embodiment;

FIG. 5 is an operation explanatory diagram showing an output signal when the magnetic sensor is abnormal.

FIG. 6 is an operation explanatory diagram showing a subroutine for detecting an abnormality of the magnetic sensor in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stator 2 Mover 3 Magnetic sensor block 10 Electromagnet 11 Coil 12 Coil bobbin 13 Iron core 14 Stator yoke 21 Permanent magnet 22 Mover yoke 30 Coil block 31 Magnetic sensor 32 Printed board 33 Fixing spacer 41 DC power supply 42 Control circuit

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Mitsumasa Mizuno 1048 Kazuma Kadoma, Osaka Prefecture F-term in Matsushita Electric Works, Ltd. GG26 GG28 HH03 HH05 HH06 HH10 HH13

Claims (5)

[Claims] 1. A thrust is applied to a mover by an interaction between a mover having permanent magnets arranged such that a plurality of magnetic poles alternately become different magnetic poles along a traveling direction, and a magnetic pole of the mover. A plurality of coils arranged in a row along the moving direction of the mover so as to provide a magnetic sensor block including a plurality of magnetic sensors for detecting a position of a magnetic pole of the mover; and a mover detected by the magnetic sensor block. A control circuit that controls the timing of energization of the coil according to the position of the magnetic pole of the magnetic sensor block. A brushless linear motor, wherein each magnetic sensor is arranged such that there is no portion having the same polarity. 2. A mover including permanent magnets arranged at regular intervals so that a plurality of magnetic poles alternately become different magnetic poles along a traveling direction, a three-phase coil, and an iron core inserted through the coil. A plurality of electromagnets are arranged along the moving direction of the mover, and one end of each iron core is magnetically coupled by a stator yoke, and arranged on the stator to detect the position of the magnetic pole of the mover. And a control circuit for controlling the timing of energization of the coil according to the position of the mover detected by the magnetic sensor block, the mover in the traveling direction. The moving distance is formed to be longer than the entire length. In the magnetic sensor block, the distance between adjacent magnetic sensors in the moving direction of the mover is 2 /
A brushless linear motor, wherein each magnetic sensor is arranged to be three times as large. 3. A signal input from the magnetic sensor block to the control circuit is a binarized output corresponding to a period during which a magnetic pole of each polarity of the mover is detected for each magnetic sensor. And wherein the control circuit determines that the signal input to the control circuit is abnormal when the signal values of the signals input to the control circuit are equal for all the magnetic sensors. Item 2
The brushless linear motor as described. 4. The brushless linear motor according to claim 3, wherein the control circuit stops energizing the coil when it determines that the input signal is abnormal. 5. The brushless linear motor according to claim 3, further comprising an indicator lamp for displaying that the control circuit has determined that the input signal is abnormal.