WO2015114794A1

WO2015114794A1 - Axial gap type rotating electric machine

Info

Publication number: WO2015114794A1
Application number: PCT/JP2014/052208
Authority: WO
Inventors: 孝石上
Original assignee: 株式会社日立製作所
Priority date: 2014-01-31
Filing date: 2014-01-31
Publication date: 2015-08-06

Abstract

A stator (9) is provided with: a plurality of teeth (9) having coil mounted portions on which a coil (7) is mounted and coil unmounted portions on which the coil (7) is not mounted; and back yokes (16) alternately arranged in a circumferential direction. Each of the back yokes (16) has a recess portion (16a) facing an adjacent back yoke (16) and thereby forming an opening portion. The outer peripheries of the back yokes (16) are fitted to the inner circumferential surface of a rotating electric machine case (12) with the coil unmounted portions inserted into the opening portions formed between the back yokes (16). This narrows the gap between the facing surfaces of the recess portions (16a), and the unmounted portions are attached between the recess portions (16a) while a gap is maintained between side peripheral surfaces of the back yokes (16) facing each other. The teeth (9) are fixed inside the rotating electric machine case (12) simultaneously in the rotational and axial directions of a rotor. The gap between the side peripheral surfaces of the back yokes blocks an eddy current loop that would otherwise circle the teeth (9), thereby preventing the development of an eddy current loss.

Description

Axial gap type rotating electrical machine

The present invention relates to an axial gap type rotating electrical machine (motor, generator).

FIG. 1 shows a conceptual diagram of an axial gap type rotating electrical machine. A permanent magnet 2 is attached to the surface of the disk-shaped rotor 1, and a stator 4 (coil and iron core) is disposed via an axial gap 3.
On the other hand, FIG. 2 is a conceptual diagram of a radial gap type rotating electrical machine. In a radial gap type rotating electrical machine, a permanent magnet 2 is attached to the outer peripheral portion of a cylindrical rotor 1, and a cylindrical stator 4 (coil 7 and iron core 8) is disposed through a radial gap 3.
The axial gap type rotating electrical machine can increase the working area of the magnet 2 to be attached by increasing the outer diameter of the rotor 3, and can obtain a high output without increasing the axial length of the rotating electrical machine. . For this reason, it is widely used for rotating electrical machines that require thinness, such as fan motors arranged on the ceiling and disk motors for driving automobiles arranged in tires.

In addition, in a rotating electrical machine of the same volume, the working area of the magnet can be secured larger than that of a radial gap type rotating electrical machine, so even if a ferrite magnet with a low magnetic force is used, a radial gap type rotation using a rare earth magnet is possible. An output equal to or higher than that of an electric machine can be obtained.
For this reason, it attracts attention as a low-cost, high-output rotating electrical machine that does not require rare earths. The same applies to SR motors (generators) and induction motors (generators) that do not use permanent magnets for the rotor 2.

Here, a conventional axial gap type rotating electrical machine stator structure will be described.
FIG. 3 shows the structure of the teeth 9 serving as the magnetic poles of the stator. For example, electromagnetic steel plates having different cross-sectional shapes are laminated in the radial direction of the stator to form a trapezoidal or sector-shaped block.
In FIG. 3, the caulking 10 is used for fixing the electromagnetic steel sheet, but there are cases where the fixing is performed using laser welding or an adhesive. Alternatively, these teeth 9 may be obtained by cutting and laminating amorphous foil bodies, or may be configured by solidifying magnetic powder having an insulating surface.
FIG. 4 shows a coil 7 and a bobbin 11 mounted around the teeth 9. In this example, the electric wire is wound around the bobbin 11 formed by resin casting, but there is a case where a tape or the like is wound around the coil 7 for insulation.

With regard to such an axial gap type rotating electrical machine, the abstract of Patent Document 1 includes “a plurality of teeth 11, a stator back yoke 12, and a fixing member 13, which constitute the stator 1 of the axial gap type motor. Each tooth 11 is formed with a leg portion 22 extending from the winding portion 21 around which the winding is wound along the axial direction X to the opposite side to the side facing the rotor, that is, to one X1 side in the axial direction. For example, a recess is formed as an engaging portion 23 on the side opposite to the side facing the rotor 22. A plurality of engaging portions 31 that can be engaged with the engaging portion 23 are formed in the fixing member 13. It is described that each tooth 11 is fixed by engaging the engaging portion 31 with the engaging portion 23 of each tooth 11.

In addition, the abstract of Patent Document 2 states that “the axial gap type rotating electrical machine 101 in which the rotor 3 is disposed oppositely across the stator 2 with a predetermined gap along the axial direction of the rotor shaft 1 includes the stator 2. A plurality of rod-shaped stator cores 22 arranged along the circumferential direction with the axis of the rotor shaft 1 as a central axis and in the axial direction of the rotor shaft 1, and the stator core 22 A disk-shaped iron core holding member 21 provided with a plurality of holes or grooves having substantially the same shape as the cross-sectional shape along the circumferential direction with the axis of the rotor shaft 1 as the central axis, and the stator iron core 21 were wound. The stator core 22 is inserted into the hole or groove of the iron core holding member 21 and is fixed and held near the center in the axial direction thereof.

JP2011-45198A JP 2010-246171 A

FIG. 5 shows an example of a stator structure of a conventional axial gap type rotating electrical machine. The bobbins 11 around which the coils 7 of FIG. 4 are wound are respectively assembled to the outer periphery of the teeth 9 of FIG. 3, and the teeth 9 to which the coils 7 are assembled are arranged annularly in the circumferential direction as shown in FIG. Insert into the electrical case 12.
In such a prior art, after inserting the tooth 9 assembled with the coil 7 into the rotating electrical machine case 12, the resin is put in the rotating electrical machine case 12 in order to fix the teeth 9 and the coil 7 in the axial direction and the circumferential direction. It needs to be poured and hardened.

6 shows a state where the bobbin 11 and the teeth 9 inserted into the case 12 are viewed from the axial direction, the outer peripheral surfaces of the resin bobbin 11 and the outer peripheral surface of the bobbin 11 and the rotating electric machine are shown. The position on the surface orthogonal to the rotation axis of the teeth 9 is obtained by contact of the inner peripheral surface of the case 12.
This structure requires a resin mold to fix the teeth 9 and the bobbin 11, and requires a rotating electrical machine that requires a large output and strong reaction force, and a severe usage environment (high temperature, large temperature change, high humidity, etc.) In the case of the rotating electrical machine used in the above, there is a drawback that a sufficient fixing strength cannot be obtained and it cannot be used.

In contrast, FIG. 7 shows an example of a conventional structure of a stator in consideration of strength.
First, the teeth 9 have a length protruding from the end surface of the bobbin 11. Also, an integrated annular back yoke 14 is prepared in which holes 13 having the outer peripheral shape of the teeth 9 are arranged in the circumferential direction. The back yoke 14 is generally configured by punching and stacking steel plates, but may be configured by cutting out a molded product of magnetic powder or a metal material. Then, by inserting a part of the tooth 9 protruding from the end surface of the bobbin 11 into the hole 13 of the back yoke, the tooth 9 is positioned in the circumferential direction, and the position of the tooth 9 is fixed on the surface orthogonal to the rotating shaft. can do.
However, in this structure, since there is no means for fixing the bobbin 11 around which the teeth 9, the back yoke 14 and the coil 7 are wound in the direction of the rotation axis, resin is injected into the case 12 after all. These must be fixed to the inner peripheral surface of the case 12.

Further, when such a back yoke 14 is used, there is a problem that an eddy current flows through the back yoke 14 and the efficiency of the rotating electrical machine is reduced. The thick line in FIG. 8 shows an eddy current loop 15 formed when a magnetic flux acts in the direction perpendicular to the paper surface when a stator using an integrated back yoke 14 as the back yoke 14 is viewed from the axial direction. .
As described above, since the loop 15 for flowing a current in a plane perpendicular to the magnetic flux is formed inside the back yoke 14 as a conductor, there is a problem that the eddy current loss is increased and the efficiency is lowered.

Therefore, in the present invention, the structure of an axial gap type rotating electrical machine that can ensure mechanical strength without using a resin mold, and in addition, rotation that can achieve high efficiency by suppressing the occurrence of eddy current loss. Provide the structure of the electric machine.

That is, an object of the present invention is to fix a tooth and a coil firmly without using a mold in an axial gap type rotating electrical machine, improve the positional accuracy and assembly accuracy of the tooth and the coil, and use a back yoke. An object of the present invention is to obtain an electric rotating machine having high strength and high efficiency by suppressing eddy current loss when the fixing strength of the teeth is improved.

In order to solve the above problems, for example, the configuration described in the claims is adopted.
The present application includes a plurality of means for solving the above-mentioned problems. For example, in the rotating electrical machine according to the present invention, a coil is assembled on the outer periphery of the teeth made of a magnetic material, and a part of the outer periphery of the teeth is formed. Is sandwiched between the divided back yokes, the outer periphery of the back yoke is press-fitted into the case and fixed, and a circumferential gap can be formed between adjacent back yokes.

More specifically, the rotating electrical machine of the present invention is an axial gap type rotating electrical machine in which the gap surface of the rotor and the stator is perpendicular to the rotating shaft, and the stator includes a coil mounting portion having a coil mounted on the outer periphery thereof. A plurality of teeth having a coil non-mounting portion and back yokes alternately arranged in the circumferential direction with respect to the teeth, each of the back yokes facing each other between adjacent back yokes It has a recess that forms an opening, and the outer periphery of the back yoke is fitted to the inner peripheral surface of the rotating electrical machine case with the coil non-mounting portion inserted into the opening formed between the back yokes. By combining, the gap between the opposing surfaces of the recess is narrowed, and the gap is maintained between at least one of the side peripheral surfaces of the back yoke facing each other. Wherein the non-coil-mounting portion by a narrow wear between said recess, said tooth, in the interior of the rotary electrical machine case, and a fixing structure to simultaneously rotationally fixed and axially of the rotor.

Along with back yokes arranged alternately in the circumferential direction, the openings formed by the recesses of the adjacent back yoke are narrowed by fitting with the inner peripheral surface of the rotating electrical machine case, and the coil is mounted out of the teeth. The teeth can be firmly fixed in the rotating electrical machine case by tightening the non-attached portion. At that time, the position of the teeth in the circumferential direction is automatically determined by the combination with the back yoke, and the position accuracy can be improved.
Moreover, by designing the circumferential dimensions and the like of each tooth so that a gap is generated in at least one of the end surfaces of the recesses of the adjacent back yoke even after being fitted to the inner peripheral surface of the rotating electrical machine case, It is also possible to prevent an eddy current loss by interrupting an eddy current loop that tries to go around the teeth.
Problems, configurations, and effects other than those described above will become apparent from the description of the following examples.

FIG. 1 is a structural diagram of an axial gap type rotating electrical machine. FIG. 2 is a structural diagram of a radial gap type rotating electrical machine. FIG. 3 is a diagram showing teeth of the axial gap type rotating electrical machine. FIG. 4 is a diagram showing a bobbin and a coil of an axial gap type rotating electrical machine. FIG. 5 is a view showing an embodiment of a stator of a conventional axial gap type rotating electrical machine. 6 is a view of the stator of the axial gap type rotating electrical machine of FIG. 5 as viewed from the axial direction. FIG. 7 is a view showing an embodiment of a stator of a conventional axial gap type rotating electrical machine using a back yoke. FIG. 9 is a diagram showing a loop of eddy current flowing in the back yoke in the axial gap type rotating electric machine of FIG. 8. FIG. 9 is a diagram illustrating a stator structure of an axial gap rotating electrical machine according to the first embodiment. FIG. 10 is a view of the stator of FIG. 9 as viewed from the axial direction. FIG. 11 is a diagram illustrating a shape example of the teeth and the back yoke according to the first embodiment. FIG. 12 is a diagram illustrating another shape example of the tooth and the back yoke according to the first embodiment. FIG. 13 is a diagram illustrating a stator structure of an axial gap type rotating electrical machine including a double rotor according to a second embodiment. FIG. 14 is a view showing a thin joint type back yoke according to the third embodiment. FIG. 15 is a diagram illustrating a stator structure of an axial gap rotating electrical machine according to the third embodiment. FIG. 16 is a view of the stator of FIG. 15 as viewed from the axial direction. FIG. 17 is a diagram illustrating an example of a steel plate punching layout diagram that forms the back yoke of the third embodiment.

Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected about the thing corresponding to the component of the conventional axial gap type rotary electric machine.

[Example 1]
A first embodiment of the present invention will be described with reference to FIG.
The axial dimension of each tooth 9 is set to be longer than the axial dimension of the bobbin 11 around which the coil 7 is wound, and the coil 7 is assembled to the base end portion of the tooth 9. Protrudes from the coil 7 so that a coil non-mounting portion where the coil 7 is not mounted is formed. As the back yoke, a plurality of back yokes 16 divided in the same number as the teeth 9 in the circumferential direction at the center of each coil 7 are used.
The back yoke 16 can be formed by punching a steel plate and laminating it in the axial direction, or by molding a magnetic powder molded product or a metal material.

That is, in this embodiment, the back yokes 16 are respectively arranged between nine teeth 9 arranged at equal intervals in the circumferential direction. Each back yoke 16 is formed with recesses 16a on both side surfaces extending in the radial direction. The back yoke 16 is arranged in the circumferential direction by positioning it on a temporary assembly jig (not shown) having nine recesses having the same shape as the axial end surface of the back yoke 9. At this time, each recess 16a forms an opening for inserting a tooth tip portion to which the coil 7 is not attached between the adjacent back yokes 16.
Then, for example, a ring-shaped rubber is externally fitted to the outer periphery of each tooth 9 with the tip of each tooth 9 inserted into the opening formed between the adjacent back yokes 16 or a lock-type band. By tightening with, for example, nine teeth 9 and back yokes 16 are temporarily assembled so as to form an annular body (a donut shape) alternately arranged in the circumferential direction.

At this time, as shown in FIG. 10, a gap 17 extending in the radial direction is formed on the inner peripheral side and the outer peripheral side so that neither side peripheral surface extending in the radial direction of the adjacent back yoke 16 contacts. . Then, by forming the annular body in which the teeth 9 are sandwiched between the divided back yokes 16 and the outer peripheral surface of the back yoke 16 is lightly press-fitted into the rotating electrical machine case (stator case) 12, each back yoke 16 is moved in the radial direction. It shrinks and is crimped to the inner peripheral surface of the rotating electrical machine case 12. At the same time, the respective concave portions of the back yoke 16 contract in the circumferential direction, and the side surfaces extending in the radial direction are strongly clamped at the tip portion of the tooth 9. Instead of light press-fitting, the tip end portion of the teeth 9 may be fixed to the inner peripheral surface of the rotating electrical machine case 12 by the back yoke 16 by shrink fitting.
Thereby, the front-end | tip part of the teeth 9 is pressurized by the back yoke 16, and is firmly fixed to the circumferential direction and the axial direction. The shape of the back yoke 16 is determined so that the gap 17 is maintained even after the temporary assembly of the back yoke 16 and the teeth 9 is press-fitted into the inner peripheral surface of the rotating electrical machine case 12.

Thus, according to the present embodiment, a stator of an axial gap type rotating electrical machine having high mechanical strength can be obtained. Further, as shown in FIG. 10, the current path 18 that is to be formed around the coil mounting portion is a gap 17 that extends between the back yokes 16 and extends in the radial direction on the inner peripheral side and the outer peripheral side. Therefore, it is possible to obtain a highly efficient rotating electrical machine while suppressing eddy current loss.
Furthermore, as shown in FIG. 11, the position of the tooth 9 in the axial direction can be fixed by providing the recess 19 on the contact surface of the tooth 9 with the back yoke 16. Or the same effect can be acquired even if it provides the convex part 20 in the teeth side 9 and the recessed part 19 in the back yoke 16 side like FIG.

In this embodiment, after the back yoke 16 is press-fitted into the inner peripheral surface of the rotating electrical machine case 12, the gap is maintained on both the inner peripheral side and the outer peripheral side. If maintained, the current path 18 is effectively interrupted. In particular, if the inner peripheral gap 7 is secured, it is effective in terms of preventing the occurrence of eddy current loss.

[Example 2]
Next, a second embodiment of the present invention will be described with reference to FIG.
This embodiment is applied to a double rotor axial gap type rotating electrical machine, and the teeth 9 are provided between the two bobbins 11 when the coils 7 (including the bobbins 11) are mounted at both ends in the axial direction. The axial dimension is designed so that a coil non-mounting portion where the coil 7 is not mounted is formed. Then, similarly to the first embodiment, the back yoke 16 is combined and tightened to the non-coiled portion and press-fitted into the rotating electrical machine case 12. Other structures are the same as those in the first embodiment.
In this way, a stator in which the coils 7 are arranged on the upper and lower surfaces in the axial direction of the back yoke 16 is obtained, and a double rotor type axial gap type rotating electric machine in which a rotor (not shown) is arranged on the upper and lower surfaces with the stator interposed therebetween. Can be obtained. The advantage of the present embodiment over the conventional structure is that, similarly to the first embodiment, even with a resin molding, a strong stator structure capable of withstanding high output can be obtained, and an eddy current loss can be suppressed and a highly efficient rotating electrical machine can be obtained. It is a point.

[Example 3]
A third embodiment of the present invention will be described with reference to FIGS.
In this embodiment, the back yoke 16 is formed by laminating thin plates such as steel plates partially connected.

As shown in FIG. 14, the portions corresponding to the outer peripheral portion 21 of the adjacent back yoke 16 are connected with a thin wall, punching a steel plate into a linearly developed shape, and laminating it to a predetermined thickness, A back yoke 16 is formed.
Then, as shown in FIG. 15, the teeth 9 are sandwiched between the adjacent back yokes 16 and fixed while the back yokes 16 are circularly rolled. After the back yoke 16 and the teeth 9 are combined, the stator until it is inserted into the rotating electrical machine case 12 can be handled integrally by fixing the joints at both ends of the back yoke 16 when it is rolled into a ring shape by laser welding or spots. The handling becomes easy.

The back yoke 16 of the third embodiment can be applied to the axial gap type rotating electric machine of any of the first and second embodiments, and also according to the present embodiment, the eddy current path 18 as shown in FIG. Is cut off on the inner peripheral side of the stator, so that a reduction in efficiency due to a thin current loss can be prevented.
Further, when punching a thin plate such as a steel plate, as shown in FIG. 17, there is an advantage of reducing the ratio of waste materials by punching back yokes 16 that are divided or connected at the outer periphery in a staggered arrangement.
Of course, a donut-shaped thin plate may be punched out and connected at either the outer peripheral portion or the inner peripheral portion of the back yoke 16.

In addition, this invention is not limited to the above-mentioned Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 1 Rotor 2 Permanent magnet 3 Gap 4 Stator 5 Bearing 6 Rotor shaft 7 Coil 8 Stator iron core 9 Teeth 10 Caulking 11 Bobbin 12 Rotating electrical machine case (stator case)
13 Integrated Back Yoke Hole 14 Integrated Back Yoke 15 Eddy Current Loop 16 Back Yoke 17 Gap 18 between Adjacent Back Yokes Current Path 19 Recess 20 Protrusion 21 Thin-walled Connection

Claims

An axial gap type rotating electrical machine in which the gap surface between the rotor and the stator is perpendicular to the rotating shaft,
The stator includes a plurality of teeth having a coil mounting portion with a coil mounted on the outer periphery and a coil non-mounting portion, and back yokes alternately arranged in the circumferential direction with respect to the teeth,
Each of the back yokes has a recess that forms an opening facing each other between adjacent back yokes,
By fitting the outer periphery of the back yoke to the inner peripheral surface of the rotating electrical machine case with the coil non-mounting portion inserted into the opening formed between the back yokes, By narrowing the non-coil mounting portion between the recesses in a state where the gap is narrowed and the gap is maintained between at least one of the side peripheral surfaces of the back yokes facing each other, A rotating electrical machine comprising a fixing structure for simultaneously fixing teeth in a rotating direction and an axial direction of the rotor inside the rotating electrical machine case.
The stator has two coils mounted from both sides in the axial direction of each tooth with the back yoke interposed therebetween, and the rotor is opposed to both axial end surfaces of the stator, respectively. The rotating electrical machine according to Item 1.
The rotating electrical machine according to claim 1 or 2, wherein the back yoke is configured by punching steel plates and laminating them in the rotation axis direction.
The rotating electrical machine according to claim 3, wherein the punched steel plates are connected at the outer periphery or the inner periphery.
The rotating electrical machine according to claim 1 or 2, wherein a convex portion is formed on one of contact surfaces of the back yoke and the non-mounting portion, and a concave portion that fits the convex portion is formed on the other.
3. The rotating electrical machine according to claim 1, wherein the back yoke is configured by solidifying magnetic powder.