JP2002247782A - Rotating electric machine and its stator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce electromagnetic vibration noise of a rotating electric machine, without increasing thermal resistance and magnetic reluctance. SOLUTION: This rotating electric machine has a rotor 3 and a stator 20 formed into an annular shape facing the rotor. The stator comprises an annular core back 11, a plurality of teeth 12 attached to the core back band made to protrude toward the inner diameter side of the core back, and coils 2 wound on the respective teeth. The teeth are fitted to grooves 111 of the core back. By having elastic connection members inserted into spaces formed between grooves of the teeth and a groove of the core back and, using the elastic members, the teeth can be displaced radially and cannot be displaced circumferentially.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary electric machine and a stator thereof, and more particularly to a rotary electric machine and a stator suitable for a case where the stator has teeth that fit into grooves of a core back.

[0002]

2. Description of the Related Art A rotating electric machine such as a generator or an electric motor includes a stator having a coil wound thereon and a rotor rotating opposite to the stator. A conventional stator has, for example, an annular core back and a teeth portion in which a plurality of teeth are radially formed, and a tenon formed on each tooth is fitted into a tenon groove formed on the core back. I have. An example of such a rotating electric machine stator is disclosed in
-252851.

[0003] An example of another conventional stator of a rotating electric machine is described in Japanese Patent Application Laid-Open No. 9-233748. In this publication, the stator core is elastically supported on the inner peripheral portion of the stator frame in order to absorb the eccentricity of the magnet and the thermal expansion of the rotor.

[0004]

By the way, between the teeth of the stator core of the rotating electric machine and the magnetic poles of the rotor, an electromagnetic force of a harmonic component due to magnetic attraction is generated in a radial direction. The electromagnetic force causes the stator core back and the frame holding the stator core to vibrate. As a result, electromagnetic noise may be radiated from the rotating electric machine to the outside.

Therefore, in the above-mentioned Japanese Patent Application Laid-Open No. 9-233748,
The stator core, which is the stator core, is elastically supported by the frame. When the elastic constant of the elastic body elastically supported is smaller than a predetermined amount, the vibration transmitted from the stator core to the frame can be insulated, and the vibration noise from the frame can be reduced. In the structure disclosed in this publication, since a gap is interposed between the stator core and the frame for vibration isolation, the heat resistance is increased, and it is difficult to radiate the heat generated by the stator core from the frame to the outside.

[0006] The stator core described in Japanese Patent Application Laid-Open No. 11-252842 has an advantage that the utilization rate of the iron core material in the stator is increased. However, in order to prevent the electromagnetic noise from being radiated from the frame to the outside, the width of the tenon where the teeth are attached to the core back must be made sufficiently small. When the width of the root of the tooth is small, the resistance to the flow of the magnetic flux increases. If the width of the tenon is widened in order to solve this problem, the vibration of the teeth is easily transmitted to the frame.

An object of the present invention is to realize a rotating electric machine and a stator thereof that can reduce electromagnetic vibration noise of a frame without increasing both thermal resistance and magnetic resistance.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, a feature of the present invention is to provide an annular core back,
It has a plurality of teeth attached to the core back and protruding toward the inner diameter side, and a coil wound around each of the teeth, wherein the teeth are vibrationally elastically coupled to the core back. .

[0009] Preferably, the vibration-mechanical elastic coupling is at least one of a spring member interposed on the side surface of the tooth, a magnetically conductive resin, and a varnish covering the coil.
Further, in the above feature, the attachment portion of the tooth to the core back has a concave portion formed on a circumferential side surface of the core back, and an elastic coupling member is interposed in the concave portion; Movably mounted; the teeth may be circumferentially connected on the inner diameter side while mounted on the core back.

Another feature of the present invention to achieve the above object is that a stator of a rotating electric machine having an annular core back and a plurality of teeth wound with windings has an inner peripheral side of the core back. Are provided with a plurality of grooves extending in the axial direction, the teeth are fitted into the grooves of the core back via elastic coupling members, and the teeth can be moved in the radial direction of the core back.

In this feature, the ratio of the natural frequency ω _n of the vibration system composed of the teeth and the elastic coupling member to the frequency ω of the electromagnetic exciting force acting when the rotating electric machine is operated at the rated speed is ω / An elastic coupling member is arranged between the teeth and the stator core such that ω _n > √ (2); the fitting portion between each tooth and the core back is formed such that the teeth are substantially immovable in the circumferential direction. The core back has a plurality of chevron-shaped protrusions on the inner diameter side, and the contact area between the teeth and the core back may be increased by forming teeth fitting portions on the protrusions. .

Another feature of the present invention to achieve the above object is that in a rotating electric machine including a stator, a rotor including a rotating shaft, and a bearing rotatably supporting the rotor, the stator has a circular shape. An annular core back,
A plurality of teeth fitted through grooves formed at a plurality of circumferential positions on the inner diameter side of the core back via an elastic member; and coils wound around each of the teeth. Is that the core back can be moved in the radial direction.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show an embodiment of an electric motor which is a kind of a rotating electric machine according to the present invention. FIG.
It is a cross-sectional view of an electric motor, and has shown the 1/4 part of the circumferential direction. FIG. 2 is a detailed sectional view of the teeth fitting portion,
FIG. 3 is a perspective view showing a tooth fitting method. Rotary axis 3
The stator 20 is arranged on the outer peripheral portion of the rotor 3 so as to face the rotor 3 having a. The outer periphery of the annularly formed stator 20 is covered with a frame 4, and the stator core 1 is held by the frame 4. On the inner diameter side of the stator core 1, a plurality of grooves 111 having a constant width into which the teeth 12 are fitted at substantially equal intervals in the circumferential direction are formed. One end of each tooth 12 is fitted in a groove 111 formed in the stator, the other end of the tooth 12 is tapered, and the expanded end protrudes toward the rotor 3. A winding is wound around the rotor-side protrusion of each tooth 12.

Details of attaching the teeth 12 to the core back 11 will be described with reference to FIGS. On both side surfaces 12a of the teeth 12, grooves 53 having a rectangular cross section are formed extending in the axial direction in the vicinity of the fitting ends to the core back 11. on the other hand,
A groove 52 having a rectangular cross section is also formed on both side surfaces 11a of the groove 111 formed in the core back 11. The elastic coupling portion 5 is formed by these grooves 52 and 53 and a guide plate 56 described later. The size of the groove 111 formed in the core back 11 has a depth H from the inner peripheral end toward the radially outer diameter side, and the width thereof is D. The width of the teeth 12 is also substantially D, so that the teeth 12 are fitted to the core back 11 exactly.

When the teeth 12 are mounted in the grooves 111 of the core back 11, the grooves 53 of the teeth 12
The teeth 12 are fitted in the grooves 111 with the first grooves 111 at substantially the same height. Thereby, a space having a rectangular cross section extending in the axial direction is formed in the contact portion 13 between the tooth 12 and the core back 11. After positioning the teeth 12 in this manner, the corrugated elastic plate 51 formed in a waveform sandwiched vertically by the guide plates 56 as shown in FIG. 3 is inserted into the space together with the guide plates 56 from the axial direction. Corrugated elastic plate 51
Is completed in the space, the guide plate 56 sandwiching the corrugated elastic plate 51 is pulled out from the opposite side. As a result, the teeth 12 are held in the grooves 111 by the rigidity of the corrugated elastic plate 51. When the teeth 12 are held in the grooves 111 using the corrugated elastic plate 51, the grooves 111 and the teeth 12
A gap 10 is formed between the end portions. This gap 10
Is provided to prevent the tip of the tooth 12 from coming into contact with the wall surface of the groove 111 even when the tooth 12 moves in the radial direction due to deformation of the corrugated elastic plate 51. That is, in the stator 20 of the present embodiment, the teeth 12 can be displaced in the radial direction by an amount corresponding to the deformation of the corrugated elastic plate.
The teeth cannot be displaced in the circumferential direction. Therefore, the flow of heat and magnetic flux from the teeth 12 to the core back 11 is not hindered, and the heat transfer performance and the performance of the electric motor can be improved. Further, it is possible to prevent the torque generated by the interaction between the rotor and the stator from vibrating the teeth in the circumferential direction.

In the above embodiment, when the teeth 12 are fitted to the core back 11, the corrugated elastic plate 51 is inserted into the space formed by the teeth. However, as shown in FIG. A protrusion 55 having a width slightly smaller than the groove 53 and a smaller height in the radial direction than the tooth groove 53 may be formed in the groove 111 of the core back 11 so as to extend in the axial direction. In this case, in order to hold the teeth 12 in the grooves 111 of the core back 11, the protrusions 55 and the grooves 5 of the teeth are used.
The corrugated elastic plate 56 is inserted from the axial direction into the space formed between the corrugated elastic plate 56 and the elastic plate 3. The corrugated elastic plate 56 may be disposed on both the outer diameter side and the inner diameter side of the protruding portion 55, or may be provided on only one side.

Further, the groove 53 and the protrusion 5 shown in FIG.
In the five shapes, as shown in FIG. 5, an elastic resin 54 mixed with magnetic powder such as iron powder is injected between the groove 53 of the tooth 12 and the protrusion 55 of the core back 11. As a result, the core back 11 and the teeth 12 are elastically connected. In this modification, the magnetic constant such as iron powder mixed into the resin reduces the magnetic resistance, and the spring constant of the elastic resin 54 can be adjusted by changing the composition of the magnetic powder and the resin body.

In the above embodiments and modifications, the corrugated elastic plate 51 and the elastic resin 54 are used to elastically couple the teeth to the core back, but the elastic coupling members are not limited to these. Therefore, a method for obtaining a requirement that the elastic coupling member should have in terms of vibration dynamics will be described below.

The teeth 12 held on the core back 11 by using an elastic coupling member, for example, a corrugated elastic plate 51 or an elastic resin 54, are not shown in FIG.
It can be regarded as a vibration system with a degree of freedom. Here, m is the mass of the teeth, k is the spring constant of the elastic body, and the core back 11 corresponds to the base portion. In this one-degree-of-freedom vibration system, assuming that the amplitude of the exciting force acting on the teeth 12 having the mass m is F and the amplitude of the exciting force received by the foundation core back 11 is Fa, the vibration transmissibility λ (= Fa / F ), and the relationship between the ratio omega / omega _n of vibrating frequency omega and the natural frequency _{ω n (= √ (k /} m)) is as shown in FIG. 7. In FIG. 7, when ω / ω _n > √ (2),
λ <1. Since λ <1 means that the excitation force of the core back is small, it means that the vibration is not easily transmitted, and it can be seen that the insulating effect can be obtained.

From the above, the teeth are held elastically.
Natural frequency ω of a vibrating system composed of an elastic body_n, And te
The ratio of the electromagnetic exciting force acting on the sheet 12 to the frequency ω is ω
/ Ω _n> Select an elastic body to satisfy the relationship of (2)
You. Therefore, if this relationship is satisfied, the elastic body
Shape or material. Also, the shape of the elastic coupling part
Is not limited to the above-described embodiment.
May be provided. The teeth and windings are alligator
If they are integrated with a tooth or adhesive,
Needless to say, the mass of the winding also includes the mass of the winding.

In order to make the natural frequency ω _n of the vibration system appropriate, the thickness of the corrugated elastic plate 51 and the pitch of the waves are changed, and the amount of the magnetic material mixed in the elastic resin 54 is adjusted. What is necessary is just to change the constant k. Instead of the elastic resin 54, a varnish for performing a varnish treatment on the winding may flow into the space to act as an elastic body. In this case, the teeth can be elastically coupled to the core back with a simple configuration. Therefore it is economical.

FIGS. 8 and 9 show a tooth and a core back according to another embodiment of the present invention. Fig. 8 shows teeth 12b
FIG. Unlike the teeth 12b shown in FIG. 1, the teeth 12b of the present embodiment are connected in the circumferential direction by the coupling member 6 on the inner diameter side. Thereby, a plurality of teeth are integrated. Although the joining member is used to integrate the teeth, it goes without saying that the entire teeth may be integrated. According to this embodiment, the same vibration insulation effect as that of the embodiment shown in FIG. 1 can be obtained, and electromagnetic noise can be reduced. Furthermore, since the teeth have an integrated structure, it is easy to maintain the roundness of the teeth,
The air gap between the rotor and the stator can be properly maintained. In addition, since the roundness is maintained, the magnetic imbalance is reduced, and the electromagnetic excitation force and the rotation unevenness of the rotor can be reduced. Further, there is also an effect of suppressing the torque generated by the interaction between the rotor and the stator from displacing the teeth in the circumferential direction.

FIG. 9 shows another embodiment of the stator core. FIG. 9 is a partial cross-sectional view of the electric motor. The inner peripheral side of the core back 11b of the stator core 1b has a waveform having a plurality of peaks protruding toward the inner diameter side. Then, a groove 11 which faces in the radial direction is formed on the crest protruding toward the inner diameter side.
1 is formed. In this embodiment, the area of the contact portion 13b between the teeth 12 and the core back 11b can be made larger than that of the embodiment shown in FIG.

According to this embodiment, the vibration insulating effect similar to that of each of the above-described embodiments and modifications is obtained, and the area of the contact portion between the core back and the teeth is increased. The thermal resistance and the magnetic resistance of the portion can be reduced. Even if the area of the contact portion between the core back and the teeth is increased, the rigidity of the elastic coupling portion is not changed, so that the electromagnetic vibration noise can be reduced. In addition, by making the core back corrugated, the area of the contact portion can be increased without increasing the thickness of the entire core back, so that the weight and cost can be reduced. In addition, the vibration is insulated by the elastic coupling between the teeth and the core back, and the electromagnetic force acting on the core back is reduced. Therefore, it is not necessary to increase the thickness of the core back and the frame to reduce noise. As a result, the weight and cost of the rotating electric machine can be reduced.

[0025]

According to the present invention, since the teeth constituting the stator of the rotating electric machine are elastically connected to the stator core, the electromagnetic vibration noise generated by the rotating electric machine is reduced without increasing the thermal resistance and the magnetic resistance. it can.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of an embodiment of a rotating electric machine according to the present invention.

FIG. 2 is a detailed transverse sectional view of a fitting portion of the teeth shown in FIG.

FIG. 3 is a perspective view illustrating a method of fitting teeth.

FIG. 4 is a cross-sectional view of a modified example of a groove formed in a stator core.

FIG. 5 is a diagram illustrating a method of processing an elastic coupling member.

FIG. 6 is a diagram of a vibration model of a stator.

FIG. 7 is a diagram illustrating vibration of a stator.

FIG. 8 is a detailed sectional view of another embodiment of the tooth.

FIG. 9 is a partial cross-sectional view of another embodiment of the stator core.

[Explanation of symbols]

1: stator core, 2: winding, 3: rotor, 3a: rotating shaft,
4: frame, 5: elastic joint, 10: gap, 11: core back, 111: groove, 12: teeth, 13: contact part between teeth and core back, 20: stator, 51: corrugated elastic plate, 52:
Groove, 53: groove, 54: elastic resin, 55: protrusion, 56: guide plate, 6: teeth connecting part.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hideaki Mori 502 Kandate-cho, Tsuchiura-city, Ibaraki Pref. Machinery Research Laboratory, Hitachi, Ltd. F-term in Hitachi Industrial Machinery Group (reference)

Claims (10)

[Claims] An annular core back, a plurality of teeth attached to the core back and protruding toward an inner diameter side, and a coil wound around each of the teeth. A stator for a rotating electrical machine, wherein the teeth are vibrationally elastically coupled to the core back. 2. The vibration-mechanical elastic coupling is at least one of a spring member interposed on a side surface of the tooth, a magnetically conductive resin, and a varnish covering the coil. The stator of the rotary electric machine according to claim 1. 3. The attachment portion of the teeth to the core back, wherein a recess is formed on a circumferential side surface of the core back, and an elastic coupling member is interposed in the recess. The stator of the rotating electric machine according to the above. 4. The stator for a rotating electric machine according to claim 1, wherein said teeth are mounted movably in a radial direction of said core back. 5. The stator according to claim 1, wherein the plurality of teeth are connected in a circumferential direction on an inner diameter side in a state where the teeth are attached to the core back. 6. A stator of a rotating electric machine comprising an annular core back and a plurality of teeth wound with windings,
A plurality of grooves extending in the axial direction are provided on the inner peripheral side of the core back, the teeth are fitted into the grooves of the core back via elastic coupling members, and the teeth can be moved in the radial direction of the core back. A stator for a rotating electric machine, characterized in that: 7. A ratio of a natural frequency ω _n of a vibration system including the teeth and the elastic coupling member to a frequency ω of an electromagnetic excitation force acting when the rotating electric machine is operated at a rated value is ω / ω. _n
The stator according to claim 6, wherein the elastic coupling member is disposed between the teeth and the stator core so as to satisfy √ (2). 8. The rotating electric machine according to claim 6, wherein the fitting portion between each of the teeth and the core back is formed such that the teeth are substantially immovable in the circumferential direction. Stator. 9. The core back has a plurality of chevron-shaped protrusions on the inner diameter side, and a contact area of the teeth and the core back is increased by forming a fitting portion of the teeth on the protrusions. The stator according to claim 6, wherein: 10. A rotating electric machine comprising a stator, a rotor including a rotating shaft, and a bearing rotatably supporting the rotor, wherein the stator has an annular core back, and It has a plurality of teeth fitted through elastic members in grooves formed at a plurality of positions in the circumferential direction on the inner diameter side, and coils wound around each of the teeth, wherein the teeth are core backed. A rotating electric machine characterized by being movable in a radial direction of the rotating electric machine.