WO2015075784A1 - Axial-gap rotary electric machine - Google Patents

Abstract

　In the present invention, the efficiency at which a winding is cooled is improved while a stator core is firmly held. An axial-gap rotary electric machine provided with: a stator; a first rotor; a second rotor; and a housing that accommodates the stator, the first rotor, and the second rotor; the stator having a plurality of stator cores, a holding member for holding the plurality of stator cores, a first winding wound on the stator cores and arranged nearer the first rotor than the holding member and a second winding wound on the stator cores and arranged nearer the second rotor than the holding member; wherein the holding member is fixed to the housing so that a portion of the holding member and an inner wall of the housing forms a channel space in which a coolant flows, and additionally the holding member extends toward a center part of the stator so that a space is arranged between the first winding and the second winding.

Description

Axial gap type rotating electrical machine

The present invention relates to an axial gap type rotating electrical machine, and more particularly to a 2-rotor-1 stator type axial gap rotating electrical machine.

An axial gap type rotating electrical machine has a structure in which a pair of disk-shaped rotors are arranged to face each other in the direction of the rotation axis, and a stator is sandwiched between the pair of rotors via a predetermined gap. There is a 2-rotor-1 stator type axial gap rotating electrical machine. The stator includes a plurality of cores arranged in the circumferential direction and windings wound around the cores.

In the axial gap rotating electrical machine having such a configuration, since the rotor is disposed so as to sandwich the stator from both sides in the axial direction, it is necessary to hold the core to the housing on the outer peripheral side of the stator. Also, in order to cool the heat of the winding, which is the main heat source, it is necessary to dissipate the heat of the winding to the housing.

As a core holding method, a technique of integrally molding a core and a housing using a synthetic resin has been proposed (for example, Patent Document 1).

Also, a method of holding the core to the housing using a stator bracket has been proposed (for example, Patent Document 2).

In the above-mentioned Patent Documents 1 and 2, a refrigerant path through which a cooling medium passes is provided outside the stator to cool the winding that is a heat source.

JP 2006-25573 A JP 2003-235221 A

However, since the technique described in Patent Document 1 holds the core only by the adhesive force between the resin and the housing, the resin deteriorates due to the temperature rise or vibration of the stator, and the adhesive strength decreases. There is a problem that decreases. In addition, since the heat of the winding is transferred to the refrigerant through the resin having low thermal conductivity, there is a problem that it is disadvantageous in terms of cooling efficiency.

The technique described in Patent Document 2 has a problem in that it is disadvantageous in terms of cooling efficiency because the heat of the winding is transferred to the refrigerant through the core and the stator bracket which are laminated bodies.

The present invention has been made in view of the above, and it is an object of the present invention to provide an axial gap type rotating electrical machine capable of improving the cooling efficiency of a winding while maintaining a core with high strength.

In order to achieve the above object, in the present invention, a stator, a first rotor, a second rotor disposed so as to face the first rotor with the stator interposed therebetween, and the fixed A stator that houses the first rotor and the second rotor, wherein the stator includes a plurality of stator cores, a holding member that holds the plurality of stator cores, and the stator. A first winding wound around the core and disposed closer to the first rotor than the holding member; and wound closer to the second rotor than the holding member while being wound around the stator core. In the axial gap type rotating electrical machine having the second winding arranged, the holding member is fixed to the housing so that a part of the holding member and the inner wall of the housing form a flow passage space through which the refrigerant flows. And the holding member is Serial toward the center of the stator so as to be disposed in a space between the first winding and the second winding, characterized in that is extended.

The present invention can provide an axial gap type rotating electrical machine capable of improving the cooling efficiency of the winding while maintaining the core with high strength.

1 is an exploded perspective view of a 2-rotor-1 stator type axial gap type rotating electrical machine 100. FIG. FIG. 2 is a partial cross-sectional view of an axial gap type rotating electrical machine 100 cut along a plane A in FIG. 1. 4 is a perspective view illustrating a fixing method for fixing the core 21 to the holding member 30. FIG. 3 is a perspective view of a state in which a core 21 is fixed to a holding member 30. FIG. It is a perspective view explaining the fixing method which concerns on the other Example which fixes the core 21 to the holding member 30. FIG. It is a perspective view showing composition of coils 22u, 22v, and 22w of each energized phase, and cores 21u, 21v, and 21w. It is sectional drawing which shows the structure of a coil | winding.

FIG. 1 is an exploded perspective view of a 2-rotor-1 stator type axial gap type rotating electrical machine 100. FIG. 2 is a partial cross-sectional view of the axial gap type rotating electrical machine 100 cut along the plane A in FIG.
<Structure of axial gap type rotating electrical machine>
The axial gap type rotating electric machine 100 includes a pair of disk-shaped rotors 10a and 10b in the direction of the rotation axis 60, and a stator 20 disposed between the pair of rotors 10a and 10b via a predetermined gap G. ,have.
The rotor 10 includes a first rotor 10a and a second rotor 10b disposed so as to face the first rotor 10a.
<Rotor>
The rotor 10a includes a magnet 11a and a structural material 12a.
In the present embodiment, a plurality of magnets 11a are arranged in the circumferential direction around the rotating shaft 60, but a single circular ring-shaped magnet may be arranged. Further, the material is not limited, and for example, it is composed of a rare earth magnet using a rare earth such as neodymium or a ferrite magnet.

Especially when a ferrite magnet with a low magnetic flux is used, it is necessary to increase the magnetic flux of the winding, that is, to increase the current flowing through the winding. Therefore, it is essential to improve the cooling performance.

The structural material 12a is provided with a recess on the side facing the stator 20, and holds the magnet 11a. The magnet 11a is held in the recess of the structural material 12a by, for example, adhesion.

The rotor 10b has basically the same configuration as the rotor 10a, although the direction in which the magnet 11a is arranged is different from that of the rotor 10a.

In addition, the rotors 10a and 10b in this embodiment are not limited to the structure shown in FIG. 1 and FIG. 1, and a specific shape may be arbitrary. For example, instead of a magnet, a switched reluctance type rotating electrical machine (SR motor) provided with a rotor core having salient poles may be employed.
<Stator>
The stator 20 includes a plurality of stator cores 21 arranged in the circumferential direction, a winding 22 wound around each core, and a holding member 30 that holds the stator core 21.
The core 21 is composed of a laminated body of magnetic thin plates such as electromagnetic steel plates and amorphous foil strips in order to suppress the generation of eddy currents. The magnetic thin plates of the core 21 are insulated by an insulating layer.

The winding 22 has a distributed winding structure wound over a plurality of stator cores 21.
The holding member 30 has an outer peripheral side of the holding member 30 fixed to the inner wall of the housing 40. The holding member 30 and the housing 40 are fixed by, for example, shrink fitting or press fitting.
The housing 40 supports the holding member 30 by contacting the outer peripheral side of the holding member 30 and the inner wall of the housing 40.

The rotary shaft 60 is fixed to the housing 40 via a bearing 50. A groove 31 is provided on the outer peripheral side of the holding member 30 along the circumferential direction. The groove 31 forms a refrigerant path 32 for allowing the refrigerant to flow between the groove 31 and the inner wall of the housing 40.

The winding 22 is divided in the axial direction via the holding member 30, and constitutes a first winding 21a and a second winding 22b.

As shown in FIG. 2, the groove 31 provided on the outer peripheral side of the holding member 30 and the inner wall of the housing 40 form a refrigerant path 32 for flowing the refrigerant. The holding member 30 extends toward the center of the stator 20 so as to be disposed in a space between the first winding 21a and the second winding 22b.

According to the axial gap type rotating electric machine of the first embodiment described above, the holding member 30 can mechanically hold the stator core 21 and the holding strength of the stator core 21 is improved.

Further, since the heat generated in the winding 22 is radiated to the refrigerant through the metal holding member having high thermal conductivity, the cooling efficiency can be improved.

Furthermore, since the refrigerant path 32 is formed in a space between the groove 31 provided on the outer peripheral side of the holding member 30 and the inner wall of the housing 40, it is not necessary to process the inner wall of the housing 40. It is also possible to reduce costs.

In addition, the winding 22 as a heat source is divided in the axial direction via the holding member 30 and the first winding 22a and the second winding 22b are formed. Since it can be used as a heat dissipation surface, it is possible to improve the cooling performance.
An O-ring 35 is provided on the outer peripheral side of the holding member 30. Thereby, the sealing performance of the refrigerant path 32 formed when the holding member 30 is held on the housing 40 is improved, and the reliability of the refrigerant path can be improved.

FIG. 3 is a perspective view for explaining a fixing method for fixing the core 21 to the holding member 30. FIG. 4 is a perspective view of a state in which the stator core 21 is fixed to the holding member 30.

The metal holding member 30 that holds the core 21 is provided with a plurality of notches 33 for holding the core 21 on the inner peripheral side. A slit 21 a for fitting into a notch 33 on the inner peripheral side of the holding member 30 is provided in a substantially intermediate portion in the axial direction of the stator core 21.

The holding member 30 is provided with steps 30a and 30b so that the thickness of the flow path forming part 37 is larger than the thickness of the core holding part 36. Further, the thickness t1 of the groove 31 is configured to be larger than the thickness t2 of the core holding portion 36. Thereby, since the thickness of the portion held by the housing 40 (= thickness of the steps 30a and 30b) is larger than the thickness of the core holding portion 30, the holding strength can be improved and the heat dissipation efficiency to the refrigerant Can be improved.

Further, the stator core 21 is fitted and held in the notch 33 from the inner peripheral side of the holding member 30. The fitting is performed by, for example, shrink fitting or press fitting. Thereby, the stator core 21 and the holding member 30 are thermally connected closely, and cooling of the stator core 21 and the coil | winding 22 can be accelerated | stimulated.

FIG. 5 is a perspective view for explaining a fixing method according to another embodiment for fixing the stator core 21 to the holding member 30.

The first winding 22a has a first center-side winding 25a arranged closer to the center of the stator 20 than the stator core 21.

The second winding 22b has a second central winding 25b disposed closer to the center of the stator 20 than the stator core 21.

The holding member 30 is extended to the space so as to occupy a volume of half or more of the space between the first center side winding 25a and the second center side winding 25b.

Thereby, since the contact area between the first winding 22a and the second winding 22b, which are heat generation sources, and the holding member 30 is increased, the thermal resistance can be reduced and the heat dissipation can be improved.

In order to further improve the heat dissipation, as shown in FIG. 5, the protrusion A on the inner peripheral side of the holding member 30 has a maximum of the first central winding 25a and the second central winding of the winding. Extend to the same plane as 25b.

FIG. 6 is a perspective view showing the configuration of the windings 22u, 22v, 22w of the respective energized phases and the stator cores 21u, 21v, 21w.

The windings 22u to 22w of each phase are wound in the circumferential direction of the respective stator cores 21u to 21w by concentrated winding.

As a result, the windings 22u to 22w are continuously wound and arranged in the axial direction, so that the contact area between the winding strands increases, so that the thermal conductivity between the winding strands is improved. Therefore, it is possible to improve the cooling efficiency.

FIG. 7 is a cross-sectional view showing the structure of the winding.

In the present embodiment, the first winding 22a and the second winding 22b are configured by winding a square wire 24.

The rectangular wire 24 is provided with an insulating layer 24b around the conducting wire 24a. Thereby, a space factor becomes higher than the coil comprised by the round wire, it becomes possible to suppress the thermal resistance between each strand, and to improve heat conductivity.

Further, the first winding 22a or the second winding 22b is wound around the stator core 21 a plurality of times so as to be arranged in a line in a direction perpendicular to the arrangement direction of the adjacent stator cores 21. The first winding 22 a or the second winding 22 b wound a plurality of times is arranged so as to be in thermal contact with the stator core 21. Thereby, even if the number of turns of the winding increases, the cooling performance of the winding can be improved.

100: Axial gap type rotating electrical machine
10: Rotor 11: Magnet 12: Structural material 20: Stator 21: Stator core 22: Winding 22a: First winding 22b: Second winding 30: Holding member 31: Groove 32: Refrigerant path 33: Notch 35: O-ring 40: Housing 50: Bearing 60: Shaft (rotary shaft)

Claims (7)

A stator,
A first rotor,
A second rotor arranged to face the first rotor across the stator;
A housing that houses the stator, the first rotor, and the second rotor;
The stator is provided with a plurality of stator cores, a holding member that holds the plurality of stator cores, and wound around the stator core and disposed closer to the first rotor than the holding member. In an axial gap type rotating electrical machine having a first winding and a second winding wound around the stator core and disposed closer to the second rotor than the holding member,
The holding member is fixed to the housing such that a part of the holding member and an inner wall of the housing form a flow path space through which a refrigerant flows.
Furthermore, the holding member is an axial gap type rotating electrical machine that extends toward a central portion of the stator so as to be disposed in a space between the first winding and the second winding. The axial gap type rotating electrical machine according to claim 1,
The first winding has the first center-side winding disposed on the side closer to the center of the stator than the stator core,
The second winding has the second central winding disposed closer to the center of the stator than the stator core,
The holding member is an axial gap type rotating electrical machine that extends to a space between the first central winding and the second central winding. An axial gap type rotating electrical machine according to claim 2,
The stator core is an axial gap type rotating electrical machine that is fixed to the holding member by shrink fitting. The axial gap type rotating electrical machine according to any one of claims 1 to 3,
The first rotor and the second rotor are axial gap type rotating electric machines each having a ferrite magnet. The axial gap type rotating electric machine according to any one of claims 1 to 4,
The axial gap type rotating electrical machine in which the first winding is wound around the stator core a plurality of times so as to be aligned in a direction perpendicular to the arrangement direction of the adjacent stator cores. The axial gap type rotating electrical machine according to any one of claims 1 to 5,
The width of the flow path space in the arrangement direction of the first rotor and the second rotor is greater than the thickness of the portion of the holding member disposed in the space between the first winding and the second winding. Large axial gap type rotating electrical machine. The axial gap type rotating electrical machine according to any one of claims 1 to 6,
The first winding and the second winding are axial gap type rotating electric machines that are square wires.

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