JPH1189199A - Axial air gap type synchronous motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an axial air gap type motor capable of reducing cogging torque without lowering the motor torque. SOLUTION: In an axial air gap type motor comprising a rotor 3 consisting of a disk-like permanent magnet having a plurality of pole pairs formed on both sides thereof being axially magnetized so that N and S polarities are positioned alternately in a circumferential direction and a first stator and a second stator having a plurality of respective stator gears 11 and 21 disposed of to oppose on both sides of the rotor 3 by means of an air gap, there are provided a first frame 12 and a second frame 22 of a nonmagnetic body provided to oppose to the outer circumference of the first stator 1 and the second stator 2, an intermediate frame 4 of a magnetic body freely movable in a circumferential direction arranged between the first frame 12 and the second frame 22, and the intermediate frame 4 is provided with a plurality of frame gears 41a, 41b, 41c and 41d which can be moved on the circumference of the intermediate frame 4 toward the diameter of the rotor 3 by means of the air gap.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial gap type synchronous motor having a permanent magnet, and more particularly to a motor for reducing cogging torque.

[0002]

2. Description of the Related Art In the prior art, an axial gap type motor is
As shown in FIGS. 3A and 3B, the magnets are magnetized in the axial direction so that the polarities of N and S are alternately located in the circumferential direction, and m (m is a positive number) on each side. A rotor 3 composed of a disk-shaped permanent magnet having a magnetic pole pair formed thereon and n (n is a positive number) stator teeth 11 (11a, 11b, 11c. ..), 21 (21
a, 21b, 21c. . . . The first stator 1 having
, A second stator 2, an armature coil 5 wound on each of the stators 1, 2, a shaft 6 disposed vertically on the surface of the rotor 3, and disposed between the first stator 1 and the second stator 2. A ring-shaped frame 7 for connecting the two stators is provided, and a first cogging torque generated between the first stator 1 and the second stator 2 is interposed between the first and second stators 1 and 2.
Stator teeth 11 of the stator 1 and the second stator 2,
21 have been proposed which are arranged so as to be shifted from each other by 180 / (m × n) degrees in the circumferential direction (for example, Japanese Patent Application Laid-Open No. 7-336967).

[0003]

However, in the prior art, the cogging torque decreases as the displacement angle increases, from the relationship between the torque and the cogging torque with respect to the displacement angle between the first and second stators shown in FIG. Then, it becomes minimum at a certain angle and then increases. Therefore, the displacement is set so that the cogging torque is minimized. On the other hand, the torque decreases as the displacement increases. For this reason, in the related art, the cogging torque is reduced, but the torque is also reduced. Also,
As can be seen from the relationship between the rotation angle of the rotor and the gap suction force in the axial direction shown in FIG. 5, there is also a problem that the motor vibrates because the gap suction force in the axial direction changes every time the rotation angle of the rotor changes. Therefore, an object of the present invention is to provide an axial gap motor that can reduce cogging torque without lowering the torque.

[0004]

In order to solve the above problems, the present invention is directed to an axially magnetized magnet in which the polarities of N and S are alternately arranged in the circumferential direction, and m (m Is an integer) disk-shaped permanent magnet formed with a magnetic pole pair, and n (n is an integer) stator teeth portions vertically opposed to both surfaces of the rotor via a gap. An axial gap type motor including: a first stator and a second stator; and a ring-shaped frame that connects the two stators disposed between the first stator and the second stator. A first frame and a second frame made of a non-magnetic material provided to face the outer periphery of the first stator and the second stator, and a circumferential direction interposed between the first frame and the second frame; Movable magnet An intermediate frame formed of a body, wherein the intermediate frame has n (n is an integer) frame tooth portions provided on the circumference in the radial direction of the rotor with a gap therebetween. Is what you do. Further, the frame teeth are individually movable within the intermediate frame toward the gap. Also,
The positions of the frame teeth are shifted by 180 / (m × n) degrees in the circumferential direction of the intermediate frame. By the above means, an intermediate frame made of a magnetic body movable in the circumferential direction having frame teeth in the radial direction of the rotor is provided between the first frame and the second frame. First, by being individually movable in the gap direction in the intermediate frame,
The cogging torque generated between the second stator and the rotor is
Since cogging torques of opposite phases are generated and canceled between the magnets of the rotor and the intermediate frame, the cogging torque can be reduced without reducing the torque.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1A is a side sectional view of an axial gap type motor showing an embodiment of the present invention, and FIG.
It is sectional drawing which follows the A 'line. The axial gap type motor according to the present invention includes a first stator and a second stator having 6 poles and 4 slots. The same reference numerals are given to the same components as those in the conventional example, and the description thereof will be omitted. Different components have been given new reference numerals. The difference from the conventional example is that a first frame 12 and a second frame 22 made of a non-magnetic material are provided facing the outer periphery of the first stator 1 and the second stator 2, and the first frame 12 and the second frame 22 are formed.
And an intermediate frame 4 made of a magnetic material that is movable in the circumferential direction is interposed between the intermediate frame 4 and the intermediate frame 4. n
Are integers) frame teeth 41a, 41b, 41c, 4
1d. Further, in the intermediate frame 4, female screws (not shown) are provided at positions where the frame teeth 41a, 41b, 41c, and 41d are provided, while female screws (not shown) are provided on the outer periphery of the frame teeth 41a, 41b, 41c, and 41d, respectively. A male screw which is not provided is provided so that each frame tooth portion can be slightly moved in the direction of the gap of the opposed rotor by the screw portion. Here, the means for moving the frame teeth is not particularly limited as described above. Further, the frame teeth 41a, 41b, 41c, 4
1d in the circumferential direction of the intermediate frame 4 by 180 / (mx
n) They are arranged shifted by degrees. In such a configuration, the cogging torque has a waveform having a peak of 12 periods, which is the least common multiple of the number of magnetic poles (6) and the number of slots (4), due to the attraction of the rotor and the stator teeth per rotation of the rotor. Similarly, a cogging torque having a peak of 12 periods is generated 2 between the rotor 3 and the frame teeth 41a, 41b, 41c, 41d of the intermediate frame 4 by the magnetic attraction force. Therefore, the stator teeth 1 of the first stator 1
First, the stator teeth 21 of the second stator 2 and the frame teeth 41a, 41b, 41c, 41d are arranged such that the cogging torques of the two cancel each other. Next, the operation will be described. FIG. 2A is a diagram illustrating a relationship between a torque and a cogging torque with respect to a misalignment angle between a stator tooth portion and a frame tooth portion, and FIG. 2B is an explanatory diagram illustrating a relationship between a misalignment angle between a stator tooth portion and a frame tooth portion. It is. Even in the arrangement where the cogging torque is minimized, the peak torque does not decrease. Rotor 3
In some cases, the cogging torque waveform deviates from the basic waveform due to the uneven magnetization, the processing error of the first and second stators 1 and 2, and the assembly error. In this case, the intermediate frame 4 and the first and second frames
The cogging torque can be reduced by finely adjusting the circumferential arrangement of the stators 1 and 2 and individually adjusting the radial gap length of the frame teeth 41a to 41d.
When the characteristics were confirmed using an actual machine, the cogging torque was reduced to the same level as the conventional example (3% of the rated torque).
Below), and the torque was increased by 120%.
Also, as shown in FIG. 5, the suction force in the axial direction becomes constant,
The problem of motor vibration has been solved.

[0006]

As described above, according to the present invention, the cogging torque generated between the stator and the rotor is generated by canceling the opposite phase cogging torque between the magnets of the rotor and the intermediate frame to cancel the torque. There is an effect that the cogging torque can be reduced without lowering.

[Brief description of the drawings]

1A is a side sectional view of an axial gap type synchronous motor according to an embodiment of the present invention, and FIG. 1B is a sectional view taken along line AA ′ of FIG.

2A is a diagram illustrating a relationship between a torque and a cogging torque with respect to a misalignment angle between a stator tooth portion and a frame tooth portion. FIG. 2B is a diagram illustrating a relationship between a misalignment angle between a stator tooth portion and a frame tooth portion. FIG.

3A is a side sectional view of an axial gap type synchronous motor showing a conventional example, and FIG. 3B is a circumferential development of a rotor and a stator shown in FIG.

FIG. 4 is a diagram showing a relationship between a torque and a cogging torque with respect to a misalignment angle between first and second stators in a conventional example.

FIG. 5 is a diagram showing an axial suction force with respect to a rotor rotation angle.

[Explanation of symbols]

 1: first stator 11: stator teeth 12: first frame 2: second stator 21: stator teeth 22: second frame 3: rotor 4: intermediate frame 41a, 41b, 41c, 41d: frame teeth 5: Armature coil 6: Shaft

Claims (3)

[Claims] 1. A disk-shaped permanent magnet which is magnetized in the axial direction so that polarities of N and S are alternately located in a circumferential direction, and has m (m is an integer) magnetic pole pairs on both surfaces. , A first stator and a second stator each having n (n is an integer) stator teeth vertically opposed to both surfaces of the rotor with a gap therebetween, and the first stator and the second stator. A ring-shaped frame disposed between the stators for connecting the two stators, wherein the frame is provided with a non-rotating frame provided opposite to the outer periphery of the first and second stators. A first frame and a second frame made of a magnetic material, and an intermediate frame made of a magnetic material movable in a circumferential direction and interposed between the first frame and the second frame; Intermediate Over arm, the axial gap type synchronous motor characterized by having a (where n is an integer) n provided with a gap toward the radial direction of the rotor on the circumference frames teeth. 2. The frame tooth portion is individually movable in the intermediate frame toward the gap.
The axial gap type synchronous motor as described in the above. 3. The axial gap type synchronous motor according to claim 1, wherein the positions of the frame teeth are shifted by 180 / (m × n) degrees in the circumferential direction of the intermediate frame.