JP4200400B2 - Axial gap type micro motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an axial gap type micromotor that is used in a micromotor such as a consumer OA device or an industrial FA device and that is provided with a permanent magnet, and particularly relates to a device that reduces cogging torque.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an axial gap type micromotor used for micromotors such as OA equipment and FA equipment is as shown in FIG.
In the figure, the axial gap type micro motor is a disk-shaped permanent magnet that is magnetized in the axial direction so that the polarities of N and S are alternately positioned in the circumferential direction, and a plurality of magnetic pole pairs are formed on both surfaces. A rotor 3 composed of magnets, a first stator 7 and a second stator 8 which are opposed to both surfaces of the rotor 3 through a gap and have a sector shape and have a plurality of stator teeth 71 and 81, respectively; The armature winding 9 wound around the stators 7 and 8, the shaft 5 disposed perpendicularly to the surface of the rotor 3, and both the stators disposed between the first stator 7 and the second stator 8 are connected. A ring-shaped frame 6 and a bearing 51 are provided.
[0003]
[Problems to be solved by the invention]
However, in the prior art, each of the stators 7 and 8 has an armature winding wound around one tooth part because the stator tooth parts 71 and 81 are fan-shaped and the tooth part has a small radial length. The number of turns of the wire 9 cannot be increased, and the electromagnetic gap between the wound armature windings 9 becomes large. As a result, every time the rotation angle of the rotor 3 changes, the axial gap suction force fluctuates, the cogging torque increases between the first stator 7 and the second stator 8 across the rotor 3, and the torque fluctuation rate also increases. There was a problem.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an axial gap type micromotor that can suppress the generation of cogging torque and reduce the torque fluctuation rate.
[0004]
[Means for Solving the Problems]
In order to solve the above problems, the present invention according to claim 1 is magnetized in the axial direction so that the polarities of N and S are alternately positioned in the circumferential direction, and m (m is an integer) on both sides. A rotor composed of a disk-like permanent magnet having a magnetic pole pair, opposed to both surfaces of the rotor in the vertical direction via a gap, and n (n is an integer) stator teeth and the stator teeth A shaft provided with a first stator and a second stator each having a wound armature winding, and a ring-shaped frame connecting both the stators disposed between the first stator and the second stator. In the direction gap type micro motor, the stator tooth portion is formed in an involute curve shape when viewed from the axial direction of the motor.
According to a second aspect of the present invention, in the axial gap micromotor according to the first aspect, the positions of the stator tooth portions of the first stator and the second stator are 180 / (mx) in the circumferential direction. n) Arranged at different degrees.
By the above means, since the armature winding is wound around each stator tooth portion formed in an involute shape, the number of turns of the armature winding wound around one tooth portion can be increased. The electromagnetic gap between the rotated armature windings can be reduced. As a result, since the gap suction force in the axial direction does not fluctuate every time the rotation angle of the rotor changes, the cogging torque can be reduced between the first stator and the second stator with the rotor interposed therebetween. Can also be reduced.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
1A and 1B show an axial gap type micro motor according to a first embodiment of the present invention, in which FIG. 1A is a sectional view showing a motor configuration, and FIG. 1B is a top view of a stator. In addition, the same code | symbol is attached | subjected about the same component as the past, the description is abbreviate | omitted, and only a different point is demonstrated.
In the figure, the points different from the conventional one are as follows.
That is, 1 is a first stator, 2 is a second stator, 11 and 21 are stator teeth provided on the stators 1 and 2, and 4 is an armature winding wound around the stator teeth 11 and 21. The stator tooth portions 11 and 21 are formed in an involute curve shape when viewed from the axial direction of the motor. Here, the following method is used to process the stator tooth portions 11 and 21 into an involute curve.
FIG. 2 is a partial cross-sectional view of a stator tooth portion processed into an involute curve shape in FIG. When the involute curve A loosens the virtual yarn C wound around the virtual circle B, the end of the virtual yarn C is 30 °, 60 °, 90 °, 120 ° counterclockwise from the position a in FIG. It is a curve drawn by moving in the order of B → C → D → E. As shown in FIG. 1B, the hatched portions surrounded by the involute curve shown in FIG. 2 are the stator teeth 11, 21, and the armature winding 4 is wound around the stator teeth 11, 21. Each stator 1 and 2 is constituted.
Next, the operation will be described.
Since each stator 1 and 2 has a configuration in which the electromagnetic gap in the circumferential direction between the stator tooth portions 11 and 21 is reduced, a current is applied to the armature winding 4 wound around each stator tooth portion 11 and 21. At this time, the rotor 3 rotates smoothly without changing the axial gap suction force each time the rotation angle changes between the first stator 1 and the second stator 2.
Next, a second embodiment of the present invention will be described.
FIG. 3 is a circumferential development of a rotor and a stator showing a second embodiment of the present invention.
In the figure, the rotor 3 made of permanent magnets with m = 6 magnetic pole pairs, the first stator 1 with n = 4 stator teeth 11a, 11b, 11c, 11d, and the same four The example of the motor provided with the 2nd stator 2 which formed stator tooth part 21a, 21b, 21c, 21d is shown.
That is, the difference from the first embodiment is that the positions of the stator tooth portions 11 and 21 of the first stator 1 and the second stator 2 are shifted by 180 / (m × n) degrees in the circumferential direction. In the figure, the misalignment angle at this time is α. By doing in this way, the cogging torque which generate | occur | produces between the 1st stator 1 and the 2nd stator 2 on both sides of the rotor 3 can be canceled effectively. Since the operation is basically the same as that of the first embodiment, the description thereof is omitted.
Next, the torque fluctuation rate of the axial gap type micromotor according to the present invention will be described.
Among the examples of the present invention, the micromotor according to the first example was actually manufactured as a prototype, and the effect was confirmed by a test. FIG. 4 is a graph showing a comparison between the present invention and the conventional torque fluctuation rate. As shown in the figure, it was found that the value of the conventional torque fluctuation rate was reduced from 5% to 2% in the present invention, and the torque fluctuation rate was reduced.
Accordingly, each stator tooth portion has an involute shape and the armature winding is wound around the stator tooth portion formed on the involute curve, so the armature wound around one tooth portion. The number of turns of the winding can be increased, and the electromagnetic gap between the wound armature windings can be reduced. As a result, it is possible to reduce the cogging torque between the first stator and the second stator with the rotor interposed therebetween without changing the axial gap suction force every time the rotation angle of the rotor changes. Can also be reduced.
[0006]
【The invention's effect】
As described above, according to the present invention, since the stator tooth portion has an involute curve shape, the axial gap that can suppress the occurrence of cogging torque between the stators across the rotor and reduce the torque fluctuation rate. There is an effect of obtaining a type micro motor.
In addition, since the positions of the stator tooth portions of each stator are shifted from each other in the circumferential direction, the cogging torque can be canceled more effectively.
[Brief description of the drawings]
FIG. 1 shows an axial gap type micro motor according to a first embodiment of the present invention, in which (a) is a sectional view showing a motor configuration, and (b) is a top view of a stator.
2 is a partial cross-sectional view of a stator tooth portion processed into an involute curve shape in FIG. 1; FIG.
FIG. 3 is a circumferential development view of a rotor and a stator showing a second embodiment of the present invention.
FIG. 4 is a graph showing a comparison between the present invention and a conventional torque fluctuation rate.
5A is a sectional view showing a motor configuration, and FIG. 5B is a top view of a stator. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1st stator 2 2nd stator 11 Stator tooth part 21 Stator tooth part 11a, 11b, 11c, 11d Permanent magnet 21a, 21b, 21c, 21d Permanent magnet 3 Rotor 4 Armature winding 5 Shaft 6 Frame A Involute curve B Virtual circle C Virtual yarn

Claims (2)

A rotor composed of a disk-like permanent magnet magnetized in the axial direction so that the N and S polarities are alternately positioned in the circumferential direction and having m (m is an integer) number of magnetic pole pairs on both surfaces; A first stator and a second stator that are vertically opposed to both surfaces of the rotor via a gap and each have n (n is an integer) stator teeth and armature windings wound around the stator teeth. In an axial gap type micromotor comprising a stator, and a ring-shaped frame connecting both stators disposed between the first stator and the second stator,
An axial gap type micro motor characterized in that the stator tooth portion is formed in an involute curve when viewed from the axial direction of the motor. The axial gap type micro motor according to claim 1, wherein the positions of the stator tooth portions of the first stator and the second stator are shifted by 180 / (m × n) degrees in the circumferential direction.

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