JPS6028760A - Reversible brushless motor without position detector with magnetic encoder - Google Patents

Abstract

PURPOSE:To facilitate assembling and to reduce the cost of a brushless motor by forming a magnetic encoder which is also used as a magnet rotor, thereby eliminating a position detector. CONSTITUTION:A rotor is formed of a rotational shaft 5 and a magnet rotor 6. The rotor 6 is formed by integrating plastic magnets 14, 15 at both sides of a rotor yoke 7. Poles 16 for a magnetic encoder are formed on the outer periphery of the magnet 14. The poles 16a, 16b for the encoder and an origin signal magnetizing unit 17 are detected by magnetic sensors 10-1, 10-2, 10-3 provided on a printed board 9, and the rotating speed of the motor is controlled on the basis of the detection signals.

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a graphiteless motor that can rotate in forward and reverse directions without the need for a position detection element having a magnetic encoder. (1) Conventionally, in order to control the rotational speed of a motor, Many motors have an encoder or tachogenerator attached to the outside of the motor, but this results in a very large motor, and there are various space limitations when applying it to small equipment. There are many inconveniences.

(2) Therefore, recently, a large number of applications have been filed for motors with a built-in rotational speed detection mechanism, and their usefulness has been recognized. Such a rotational speed detection mechanism has advantages and disadvantages depending on its method.Especially in the case of acoustic brushless motors in which the rotor rotates at a constant speed, frequency power generation, which is formed by an FG pattern that can be formed at low cost and frequency detection magnetic poles, is particularly important for acoustic brushless motors in which the rotor rotates at a constant speed. Many methods using machines are used. The frequency detection magnetic pole for this frequency generator is formed by forming a driving magnetic pole on an annular ferrite magnet, and then using another magnetizing yoke to detect the frequency by double magnetizing the driving magnetic pole. It forms the magnetic pole for use.

Because there is no element that is particularly thick (such as Since a power generation signal can be obtained from the magnetized terminals of the FG pattern made up of the frequency detection terminals (120 poles), the rotational speed of the motor can be controlled using this signal.

However, the printed circuit board having this FG pattern is arranged on the stator armature surface facing the driving magnetic pole surface of the magnet rotor on which the frequency detecting magnetic pole is formed by double magnetization means, and the printed circuit board is arranged on the stator armature surface opposite to the driving magnetic pole surface of the magnet rotor on which the frequency detecting magnetic pole is formed by double magnetization means. must be faced.

Therefore, the air gap between the driving magnetic pole surface of the magnet rotor and the stator yoke of the stator armature opposing this increases by the thickness of the printed circuit board having the FG pattern, and a strong magnetic flux density cannot be obtained by that much. With that ratio, a large rotational torque cannot be obtained, and as a result, a highly efficient brushless motor cannot be obtained.

In order to solve this drawback, it is necessary to omit the printed circuit board with the FG pattern, but in this case the useful frequency generator described above cannot be obtained.

(3) The frequency generator described in (2) above is useful when the motor rotates at a constant speed, but it depends on the capabilities of the motor. Therefore, in order to be able to control the position, further means must be provided, such as, for example, an optical encoder. In this case, the device will not only be large but also very expensive as in (1) above. However, in many fields including the robot industry, there is a strong demand for the motor to be provided with position control means in addition to rotational speed control means.

(4) Although a brushless motor equipped with a rotation speed detection means for rotation speed control forms a frequency generator, it can only detect rotation of the rotor in one direction, making it difficult for robots that require forward and reverse rotation of the motor. It is unsuitable as a brushless motor for etc. In other words, although the motor with the frequency generator described above can rotate forward and reverse, a signal to reverse the motor from the set position cannot be obtained, so the setting (including when a specified signal is obtained)
I'm here. Therefore, unless an optical encoder or the like capable of generating two-phase signals, ie, A-phase and B-phase signals, is used, the coating method has the same drawbacks as described above.

(5) Brushless motors do not have brushes, so they do not have many drawbacks such as accidents caused by sparks caused by brushes coming into contact with the commutator, and reduced lifespan caused by contact between the brushes and commutator. It is ideal for use in equipment that can be expected to have a long life, such as Soto.

To this end, brushless motors eliminate commutators and brushes, and detect the north or south magnetic pole of the driving magnetic pole of the magnet rotor using a position sensing element such as a Hall element or a magnetic sensing element such as a Hall IC. It is well known that a semiconductor rectifier is driven at predetermined time intervals to supply current in a predetermined direction to a child coil in order to rotate a magnet rotor in a predetermined direction. However, in conventional brushless motors, each armature coil
It is necessary to use one position sensing element for every two or two armature coils. The larger the number of armature coils, the more expensive position sensing elements are required, resulting in a very expensive brushless motor. In addition, if the position sensing elements are not properly arranged, it will not be possible to properly energize the device, but if there are a large number of position sensing elements, the arrangement will be cumbersome and the device will not be suitable for mass production.

(Object of the present invention) The present invention has been made based on the above circumstances, and includes (1) A phase,
By incorporating a magnetic encoder that can take the B-phase signal and also serves as a magnetic sotrotor,
To obtain a brushless motor that can be formed compactly and inexpensively by rationally incorporating a rotation speed detection mechanism, (2) to form a magnetic encoder thereof at low cost, and (3) to obtain a suitable magnetic encoder using the magnetic encoder. By making it possible to perform forward/reverse rotation control, variable speed control, pulse control, and predetermined position stop control, and (4) by using the magnetic encoder described above, the position detection element is unnecessary and assembly is easy. The purpose of this invention is to provide a brushless motor that can be mass-produced at low cost, has an efficient magnetic encoder, and is capable of forward and reverse rotation and does not require position detection.

Other objects of the invention will become apparent from the description below.

(Means for Achieving the Object of the Present Invention) The object of the present invention is mainly to connect the N and S driving magnetic poles, which face the stator armature and rotate relative to each other, to 2p (+
) is a positive integer of 1 or more) In a brushless motor equipped with a magnetic rotor that moves to the right, magnetic poles for magnetic encoders are formed by alternately magnetizing N-pole or S-pole strength or weaker magnetic pole parts or N-pole and S-pole at fine pitches. a part is formed on the magnet rotor, and an origin signal magnetized part is provided on the magnet rotor, two magnetoresistive elements are made to face the magnetic encoder magnetic pole part, and the two magnetoresistive elements are connected to each other as appropriate in the circumferential direction. Arrange the intervals with different phases, or use 2 above.
The magnetic pole portions for the magnetic encoder at the portions facing the magnetoresistive elements are formed with appropriate intervals and phases shifted in the circumferential direction, and the origin signal magnetization is detected on the fixed side on the trajectory facing the origin signal magnetization portion. This is achieved by providing a brushless motor that is capable of forward and reverse rotation without the need for a position sensing element having a magnetic encoder, which is characterized by being equipped with a magnetic resistance element.

Means for achieving other objectives will become apparent from the following description.

(First Embodiment of the Present Invention) A first embodiment of the present invention will be described with reference to FIGS. 1 to 3. 1 is a disc type brushless motor, 2
1 is a disc-shaped brushless smoke body, which is formed by a cup body 2a made of a magnetic material and a disc body 2b. 6,4
5 is a bearing, 5 is a rotating shaft rotatably supported by a bearing 3.4, 6 is a magnet rotor integrally molded with a plastic magnet on the rotating shaft 5, 7 is a rotor yoke having a through hole 8, and 9 is a rotor yoke. Magnet rotor≠An annular printed circuit board having a conductive wiring pattern (not shown) on the upper surface fixed to the inner surface of the cup body 2a facing the upper surface of the cow 6, 10-1, 10-2, and 10-3 are printed respectively. A magnetoresistive element including a magnetic sensor such as a so-called magnetoresistive element, a Hall IC, a Hall element, etc., which is arranged in the radial direction on the substrate 9 and is connected by soldering to a conductive wiring pattern (not shown) of the printed circuit board 9. , the magnetoresistive elements 10-1 and 10-2 are positioned on the printed circuit board 9 facing a magnetic pole part for a magnetic encoder (to be described later), and are shifted in phase in the circumferential direction by one magnetic pole width of the magnetic pole part for a magnetic encoder. , is arranged so that two-phase position signals of phase B can be obtained.
A magnetoresistive element 10 is provided. Note that the above element 10-1
．． . . . It goes without saying that a device in which two or more of 10-3 are combined into one element may be used. 11 is a disc body 2b
12 is a stator armature consisting of 13 groups of coreless armature coils arranged at equal intervals on the surface of the printed circuit board 11 so as not to overlap each other;
It faces the lower surface of the magnet rotor 6.

As mentioned above, the rotor consists of a rotating shaft 5 and a magnet rotor 6.
It consists of a rotor yoke 7 having a through hole 8 and a rotating shaft 5.
The two are molded with plastic magnets and integrated. In this case, since the through hole 8 is provided, the rotor yoke 7
Since plastic magnets can be easily formed on both sides of the rotor yoke 7, plastic magnets are formed on both sides of the rotor yoke 7. The plastic magnet 14 on the upper surface of the rotor yoke 7 and the plastic magnet 15 on the lower surface are integrated through the through hole 8.
Since these are also integrated, there is no need to separately adhere and fix the upper and lower plastic magnets 14 and 15 to the rotor yoke 7 with adhesive. In addition, since the position of the rotary shaft 5 is determined during the molding process, the rotor yoke 7 may be fixed to the rotary shaft 5 as in the past, or the rotor yoke 7 may be
It is possible to solve troublesome problems when adjusting the fixing strength and dynamic balance when fixing a driving magnet to a drive magnet. On the outer periphery of the plastic magnet 14 on the upper surface, a magnetic encoder magnetic pole part 16 of approximately 180 poles, for example, having N and S magnetic poles alternately along the circumferential direction at a fine pitch, is magnetized, and a minute air gap is formed. The magnetoresistive elements 10-1 and 10-2 provided on the printed circuit board 9 are opposed to each other. The above-mentioned magnetic encoder magnetic pole portions 16 each have a magnetic 1° resistance element 10-1. It consists of magnetic encoder magnetic pole parts 16a and 16b facing 10-2. Reference numeral 17 denotes an origin signal magnetized portion formed at one location on the inner circumferential portion of the magnetic encoder magnetic pole portion 16b of the plastic magnet 14 to have a width equivalent to one magnetic pole of the magnetic encoder magnetic pole portions 16a, 16b. The printed circuit board 9 is separated by
The magnetoresistive element 10-6 for detecting the origin signal magnetized portion is opposed to the magnetoresistive element 10-6 for detecting the origin signal magnetized portion. Although the origin signal magnetized portion 17 is magnetized to the S pole in the figure, it may be a Y pole, and the portion of the plastic magnet H other than the magnetic encoder magnetic pole portion 16 is magnetized to the S pole. If it is magnetized to NriA, it may be magnetized to NriA, and if it is magnetized to N-pole, it may be magnetized to S-pole. Furthermore, the origin signal magnetized portion 17 may be formed separately from the magnetic encoder magnetic pole portion 16, or may be formed integrally and simultaneously. The plastic magnet 15 on the lower surface of the rotor yoke 7 is magnetized with eight drive magnetic poles 18 having N and S magnetic poles, as shown in FIG. The driving magnetic pole 18 and the stator armature 12 consisting of a group of six armature coils 13 facing the magnetic pole 18 form a so-called conventional disk-type brushless motor.

The armature coil 13 has an opening angle of radial conductor portions 13a and 13a' that contribute to the generated torque, which has a width that is approximately equal to the magnetic poles of the driving magnetic pole 18, that is, since the driving magnetic pole 18 has 8 poles, the opening angle is 45 degrees. It has a fan frame shape with an opening angle width of . Incidentally, the circumferential conductor portions 13b, 1 of the armature coil 13
3b' is a conductor portion that does not contribute to the generated torque.

As is clear from FIG. 2, the six armature coils 13 are arranged at regular intervals so as not to overlap each other, and the arrangement of the armature coils 13 forming the stator armature 12 is as shown in FIG. Regardless of what is shown in FIG. Armature coil 16 shown
It is not limited to. Similarly, it goes without saying that the driving magnetic pole 18 may also be magnetized and formed in a skewed manner. 1q-+iig=magnetic pole part.

The first embodiment of the present invention has the above configuration. Therefore, by detecting the magnetic encoder magnetic pole part 16 by the magnetic sensors 10-1 and 10-2 forming the magnetic encoder, so-called two-phase signals of A phase and B phase can be obtained, so that the rotation speed, The rotation amount and rotation speed can be determined, and the rotation can be performed in forward and reverse directions. Furthermore, there is no position detection element such as a Hall element or Hall IC for energizing the armature coil 13 as in the prior art (but the magnetic sensor 10-6 and the origin signal magnetization section 17
Therefore, the magnetic sensor 10-6 receives the origin signal magnetized unit 17.
The reference point is the time when the magnetic sensor 10-1.1 is detected.
0-2 detects the detection pulse obtained by detecting the m-pole portions 16a and 16b for the magnetic encoder using a counter, and uses, for example, a pulse distributor to detect the armature coil at an appropriate position for each predetermined pulse. By sequentially passing a current in an appropriate direction through the magnet rotor 13 through a polarity conversion circuit, rotational torque in a predetermined direction is obtained by the armature coil 16 group and the driving magnetic pole 18, so that the magnet rotor 6 rotates in a predetermined direction. . Note that when the magnetic sensor 10-6 does not detect the origin signal magnetized portion 17, for example, a pulse current is applied in a predetermined direction to the armature coil 13 group to rotate the magnet rotor 6 in a predetermined direction, and the magnetic sensor 10-6 The origin signal magnetized portion 17 is detected by 10-6. When the magnetic sensors 10 to 3 detect the origin signal magnetized part '17, the digital circuit including the counter is operated as described in Section 2.
Even if a position detection element is not required, the digital circuit can sequentially supply current in a predetermined direction to the group of armature coils 16, so that the magnet rotor 6 can be rotated in a predetermined direction. To reverse the magnet rotor 6,
All you have to do is convert the polarity of the polarity conversion circuit. In addition, if a memory function circuit is provided, once the origin (signal magnetization section 17) is memorized, the origin signal magnetization section 17 will be used from the next time.
There is no need to search for the origin, and the counter always operates based on the origin signal position, so as soon as the power is turned on to the drive circuit, the magnet rotor moves in a controlled direction at a prescribed rotational speed without having to search for the origin. The rotating part 6 may be a plastic pole or a non-magnetized part when placed in a part facing the same circumferential locus as the magnetic pole part 16 for the magnetic encoder.
A magnetic encoder magnetic pole portion 16 is formed on the outer peripheral portion by double magnetization means. The magnetic encoder magnetic pole part 16 has a strong N pole (or S pole) N1ff1 (or S
It is formed by alternately magnetizing and forming a polar (pole) magnetized portion and a weak N-pole (or S-pole) magnetized portion at a fine pitch. The stiff and strong N-pole (or S-pole) magnetized portion naturally acts as an N-pole (S-pole), and therefore acts as an S-pole (or N-pole).

As a result, when the magnetic sensor 10-1 and 10-2 are facing the N pole of the encoder magnetic pole part 16,
The other one is arranged so as to face N Ili with a phase shift in the circumferential direction. The origin signal magnetized section 17 is magnetized to an N pole at one location on the inner circumference of the encoder Kawaguchi pole section 16, and a magnetic sensor 10-6 is installed at a position where the origin signal magnetized section 17 can be detected. The driving magnetic pole 18 is 4 in the thickness direction.
The driving magnetic pole part 18 has a large number of N and S magnetic poles alternately arranged at a fine pitch on the outer peripheral surface thereof.
A magnetic encoder magnetic pole part 16 is formed by heavy magnetization means, and a magnetic sensor is placed on the surface facing the magnetic pole part 16.

On the outer peripheral surface of the Yagnet rotor B, an N-pole origin signal magnetized part 17 similar to the above is magnetized, and the outer peripheral surface excluding the magnetized part 17 is magnetized into an S-pole magnetized part 20. , the magnetized part 1
A magnetic sensor 10-6 is disposed on the fixed side facing 7.20.

As another example, the magnetic encoder magnetic pole part 16 may be formed on the outer circumferential surface of the magnet rotor 6, and the origin signal magnetized part 17 may be formed on the same surface as the drive magnetic pole 18; 516 and origin signal magnetization section 17
Both may be formed on the outer circumferential surface of the magnet rotor 6. When forming such a magnetized portion on the outer circumferential surface of the magnet rotor 6, a plastic magnet is separately formed on the outer circumferential surface, and this plastic magnet It may be formed by magnetization.

As is clear from the above, the present invention provides (1) a brushless motor that can be magnetically controlled; (2) the above (1)
) magnetic encoder can be formed at low cost; (3) multifunctional control such as forward/reverse rotation control, variable speed control, pulse (stepped impression) control, and predetermined position control of the motor can be performed; (4) position detection. Since no elements are required, when the number of phases or armature coils increases, current can be passed in a specific direction to the armature coil at a particularly low cost because there is no horizontal positioning element, and rotation in a specific direction can be achieved. can be made to do
In addition, since no position sensing element is required, many lead wires for the position sensing element are eliminated, resulting in a cleaner appearance and easier manufacture, making it possible to easily mass-produce brushless motors with the above-mentioned effects. have an effect. Although the present invention has been described using a disc-type brushless motor as an example, the present invention is also applicable to a cylindrical brushless motor, and also to a ferrous core-type brushless motor. In addition, mere improvements based on the spirit of the present invention also belong to the technical scope of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a first embodiment of the present invention, FIG. 2 is an exploded perspective view of the main parts of FIG. 1, and FIG. 3 is a bottom view of a magnet rotor having eight driving magnetic poles. FIG. 4 is a top view of a magnet rotor to show a second embodiment of the present invention;
FIG. 5 is a bottom perspective view of a magnet rotor showing a third embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Disc type brushless motor, 2... Disc type brushless motor body, 2a... Cup body, 2
b... Disc body, 6, 4... Bearing, 5... Rotating shaft, 6... Magnet rotor, 7... Rotor yoke, 8... Through hole, 9... Printed circuit board, 10-1.
.... 10-6... Magnetic sensor, 11... Printed circuit board,
12... Stator armature, 16... Armature coil,
14.15...Plastic magnet, 16...
Magnetic pole part for magnetic encoder, 17... origin signal magnetization part,
18... Drive magnetic pole, 19... Non-magnetic pole part, 20...
・S pole magnetized part. Patent applicant Figure 5 11 282--3

Claims (1)

[Claims] 1. N that faces the stator armature and rotates relative to it;
In a brushless motor that has a magnetic rotor with S driving magnetic poles 2p (p is a positive integer of 1 or more) to the right, the strong and weak portions of the N or S poles or the N and S poles are alternately magnetized at fine pitches. The formed magnetic encoder magnetic pole part and origin signal magnetized part are provided on the magnet rotor, two magnetic sensors are made to face the magnetic encoder magnetic pole part, and the two magnetic sensors are arranged at an appropriate interval and phase from each other in the circumferential direction. Alternatively, the magnetic pole parts for the magnetic encoder facing the two magnetic sensors are formed with appropriate intervals and phases shifted in the circumferential direction, and the magnetic sensor for detecting the origin signal magnetized part is arranged in a manner that the magnetic pole parts for the magnetic encoder face the two magnetic sensors. Brushless motor that can rotate in reverse. 2. 'The magnetic pole part for the magnetic encoder is formed by a double magnetization means on the driving magnetic pole part. A position sensing element having a magnetic encoder as set forth in claim 1 is unnecessary. Brushless motor that can rotate forward and reverse. 3. A position sensing element having a magnetic encoder according to claim 1 or 2, wherein the magnetic pole part for the magnetic encoder is magnetized and formed separately from the magnetic pole part for driving. A brushless motor that can be rotated in forward and reverse directions without the need for it. 4. The magnetic pole part for the magnetic encoder is formed on a different surface from the magnetic pole part for driving, and the position detection element having the magnetic encoder according to claim 3 is not required and the magnetic encoder can be rotated in forward and reverse directions. possible brushless motor. 1. The brushless motor has a rotating shaft and a rotor yoke molded with plastic magnets, and plastic magnets are formed on both sides of the integrated rotor yoke.
Alternate N and S magnetic poles on the plastic magnet on one side of the rotor yoke 2p (p is a positive integer of 1 or more)
A disc-type brushless motor in which a driving magnetic pole is magnetized, a stator armature is provided on the side facing the driving magnetic pole, and a magnetic encoder magnetic pole is formed on a plastic magnet on the other surface of the rotor yoke. A brushless motor that does not require a position detection element having a magnetic encoder and is capable of forward and reverse rotation as claimed in claim 3 or 4. 1. The rotor yoke has a through hole other than for inserting the rotating shaft, and plastic magnets on both the upper and lower surfaces of the rotor yoke are integrally formed through the through hole. A brushless motor that does not require a position detection element having a magnetic encoder as described in Section 1 and is capable of forward and reverse rotation. ? A position having a magnetic encoder according to any one of claims 1 or 3 to 6, wherein the magnetic pole part for the magnetic encoder and the origin signal magnetized part are formed on different surfaces. A brushless motor that does not require a detection element and can rotate in forward and reverse directions. j. The magnetic encoder according to any one of claims 1 or 3 to 6, wherein the magnetic pole part for the magnetic encoder and the origin signal magnetized part are formed on the same surface. A brushless motor that can rotate in forward and reverse directions without the need for a position detection element. The stator armature is characterized in that the conductor portion that contributes to the generated torque consists of an armature coil group formed with an opening angle width that is approximately equal to the driving magnetic pole of the magnet rotor. 9. A brushless motor having a magnetic encoder according to any one of Item 8, which does not require a position detection element and is capable of forward and reverse rotation. 0. A brushless motor which does not require a position detection element having a magnetic encoder and is capable of forward and reverse rotation as claimed in claim 9, wherein the armature coil groups are arranged at equal intervals so as not to overlap each other. .