Rotary electric machine

Abstract

To provide a rotary electric machine which has high insulation performance, suppresses the increase in weight and deterioration in the insulation performance, and thereby is reduced in weight and size.SOLUTION: A rotary electric machine comprises a stator core, and a coil wound around the stator core and having a coil end formed so as to project to an end surface of the stator core in an axial direction. The coil end is arranged in a sealed space.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a rotating electrical machine.

Background Art

[0002] Conventionally, in a rotating electrical machine such as an in-vehicle motor or generator, conductors in the range protruding from the stator core are insulated from other components to prevent flashover. As a general insulation method, for example, a method of providing a certain space distance between the conductors in the range protruding from the stator core and other components is known. In addition, when there is a pressure difference between the inside and outside of the rotating electrical machine, there is a possibility that liquids such as rainwater and machine oil may enter the rotating electrical machine from the bearing portion due to the pressure difference. Therefore, the rotating electrical machine is provided with air vents in the housing so that no pressure difference occurs between the inside and outside of the rotating electrical machine.

[0003] However, when air is used as an insulating medium in the above-described rotating electrical machine, it may be affected by external factors such as humidity or atmospheric pressure. Therefore, it is necessary to design assuming the worst value in the use environment, and as a result, the required insulation performance becomes high and the rotating electrical machine becomes large-sized. As a means for preventing the influence of the external environment, a method of molding the conductors in the range protruding from the stator with resin is generally known (see, for example, Patent Document 1 and Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the conventional rotating electrical machines disclosed in Patent Document 1 and Patent Document 2 described above, since the conductors in the range protruding from the stator core are insulated by resin molding, there is a problem that the weight increases due to the use of a large amount of resin. In addition, since the resin often does not have self-insulation recovery characteristics, there is a problem that the insulation performance deteriorates due to aging.

[0006] The present disclosure discloses a technique for solving the above problems, and aims to provide a rotating electrical machine with high insulation performance that suppresses an increase in weight and a decrease in insulation performance, and as a result, is lightweight and miniaturized.

Means for Solving the Problems

[0007] The rotating electrical machine of the present disclosure includes a stator core and a coil wound around the stator core and having a coil end formed to protrude from an axial end face of the stator core, and the coil end is arranged in a sealed space.

Effects of the Invention

[0008] According to the rotating electrical machine of the present disclosure, an increase in weight and a decrease in insulation performance are suppressed, and as a result, a rotating electrical machine with high insulation performance that is lightweight and miniaturized can be obtained.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0010] The present disclosure is a technology applicable to all rotating electrical machines such as in-vehicle alternators, motors, in-vehicle drive devices, integrated rotating electrical machines for electronic devices, and induction motors. Hereinafter, the rotating electrical machine according to Embodiment 1 will be described with reference to the drawings. In each of the drawings, the same reference numerals indicate the same or corresponding components.

[0011] Embodiment 1. FIG. 1 is a schematic cross-sectional view showing the rotating electrical machine according to Embodiment 1. Note that FIG. 1 shows the upper half with respect to the center line and is shown with one side omitted. As shown in FIG. 1, the rotating electrical machine 100 has, for example, a substantially bowl-shaped housing 1, a shaft 5 rotatably supported in the housing 1 via a pair of bearings 6, a rotor 2 which is a cylindrical member and rotates integrally with the shaft 5, and a stator 3 disposed opposite to the outer periphery of the rotor 2. The stator 3 is an annular member and is coaxially disposed with the rotor 2 so as to surround the outer periphery of the rotor 2.

[0012] The stator 3 has, for example, a stator core 3a having a plurality of slots (not shown) and a conductive portion 4 which is a coil wound around the stator core 3a. The conductive portion 4 has a core inner conductive portion 4a located inside the stator core 3a and a core outer conductive portion 4b located outside the stator core 3a. The core outer conductive portion 4b is a coil end formed to protrude from the axial end face of the stator core 3a.

[0013] As shown in FIG. 1, the housing 1 is partitioned by a partition wall 7 into a core outer conductive portion 4b side and a housing 1 side (including the outside of the housing 1). The partition wall 7 provided on the housing 1 side (including the outside of the housing 1) is disposed between the axial end of the core outer conductive portion 4b and the wall surface of the housing 1. Further, the inside of the housing 1 is partitioned by the partition wall 7 into a core outer conductive portion 4b and a rotor 2 side. The core outer conductive portion 4b which is a coil end is surrounded by the partition wall 7 and is disposed in a sealed space 8 where there is no air exchange with the rotor 2 side and the outside of the housing 1.

[0014] Note that the partition wall 7 is not limited to the structure shown in FIG. 1 as long as it can form a sealed space 8. The housing 1 only needs to be partitioned by the partition wall 7 into at least the core outer conductive part 4b side and the housing 1 side (including the outside of the housing 1). Thereby, a space 8 is formed around the core outer conductive part 4b where it is not affected by the air pressure and humidity on the housing 1 side (including the outside of the housing 1). Therefore, in an environment with low air pressure and high humidity, the space insulation ability during manufacturing can be maintained. Thus, for example, the reference value of the insulation performance required for the rotating electrical machine 100, such as the reference value of the insulation performance between the coil end and other components or the reference value of the phase-to-phase insulation of the U-phase, V-phase, and W-phase of each coil, can be reduced.

[0015] For example, according to IEC60034, as the altitude increases, due to the influence of the decreasing air pressure, the insulation distance to be extended is described, and it is proposed to ensure an insulation distance 1.48 times that on flat ground at an altitude of 5000 m. However, according to the rotating electrical machine 100 according to the first embodiment, there is no need to ensure such an insulation distance. Also, compared with a conventional rotating electrical machine in which the core outer conductive part 4b is resin-molded, the rotating electrical machine 100 according to the first embodiment has heat transfer by convection, so it is easy to cool the heat of the conductive part 4. Further, the rotating electrical machine 100 according to the first embodiment is not affected by carbonization due to discharge or the influence of aging deterioration, and can maintain the insulation performance over a long period.

[0016] Also, the inside of the housing 1 only needs to be partitioned by the partition wall 7 into at least the core outer conductive part 4b and the rotor 2 side. Thereby, the rotor 2 side can form a space regardless of the periphery of the core outer conductive part 4b. Therefore, the rotor 2 side can maintain the same air pressure as the outside of the housing 1. Note that the partition wall 7 is also provided on the axial end face of the stator core 3a.

[0017] The shape of the partition wall 7 is not particularly limited as long as it defines the core outer conductive portion 4b side, the housing 1 side (including the outside of the housing 1), and the rotor 2 side. The coil end may be covered with a dome-shaped member. Further, the partition wall 7 may be formed so as to define the core outer conductive portion 4b including the stator core 3a or the core inner conductive portion 4a from the outside of the housing 1 and the rotor 2 side. As long as the periphery of the core outer conductive portion 4b, which is the coil end, can be sealed, the position and shape of the partition wall 7 are not limited. Further, the partition wall 7 is formed of a metal material such as aluminum or iron, for example.

[0018] FIG. 2 is a schematic cross-sectional view showing a modified example of the rotating electrical machine according to Embodiment 1. Note that FIG. 2 shows the upper half with respect to the center line in the same manner as FIG. 1, and one side is omitted. As shown in FIG. 2, the space 8 defined by the partition wall 7 on the core outer conductive portion 4b side, the housing 1 side (including the outside of the housing 1), and the rotor 2 side is defined in an airtight manner. The space 8 on the core outer conductive portion 4b side defined by the partition wall 7 is preferably maintained at a certain pressure, for example. Further, as shown in FIG. 2, the space 8 can be filled with a fluid 9 having specific insulation properties, more specifically, a gas, a liquid, a sol-gel material, or a clay. Examples of the fluid 9 include, but are not limited to, pressurized air, depressurized air, sulfur hexafluoride, insulating oil, silicone, Teflon clay (Teflon: registered trademark), and the like. Further, the step of filling the space 8 with the fluid 9 such as pressurized air may be performed before or after housing the rotor 2 and the stator 3 in the housing 1.

[0019] As shown in FIG. 2, by making the space 8 enclose the fluid 9, the insulation performance is superior to the state in which normal air is enclosed. Therefore, in the modified example of the rotating electrical machine 100 according to Embodiment 1, for example, the insulation distance between the coils can be made shorter. Further, depending on the insulating material selected, heat transfer can be improved compared to normal air, and the heat of the conductive portion 4 can be more easily cooled than when the core outer conductive portion 4b is resin-molded. Also, by properly selecting the insulating material according to the required insulation performance, it is possible to adjust the insulation performance, cooling performance, or gas cost even for the same shape. Furthermore, since the interior of the housing 1 is partitioned into the outer core conductive part 4b and the rotor 2 side, the insulating fluid 9 enclosed in the outer core conductive part 4b does not affect the rotor 2, so the windage or mechanical loss of the rotating electrical machine 100 is not increased.

[0020] From the above, the rotating electrical machine 100 includes a stator core 3a and a coil wound around the stator core 3a and having coil ends formed to protrude from the axial end faces of the stator core 3a. The coil ends, which are the outer core conductive parts 4b, are arranged in the sealed space 8. Also, the rotating electrical machine 100 is disposed in the housing 1 and has a stator 3 having the stator core 3a and the coil which is the conductive part 4, and a rotor 2 rotatably supported within the stator 3. The coil ends, which are the outer core conductive parts 4b, are arranged in the sealed space 8 so as to prevent air exchange with the rotor 2 side and the outside of the housing 1. The space 8 is formed by the partition wall 7.

[0021] By doing so, compared with the prior art in which the coil ends, which are the outer core conductive parts 4b, are insulated by a space distance, since it is not affected by external atmospheric pressure or humidity, the requirement for the insulation distance for the rotating electrical machine 100 can be reduced, and the rotating electrical machine 100 can be miniaturized. Furthermore, compared with the prior art in which the coil ends, which are the outer core conductive parts 4b, are insulated by resin molding, it is possible to improve the cooling performance by convection and reduce the weight of the rotating electrical machine 100. Also, it is possible to prevent deterioration of the insulation performance due to discharge or aging degradation.

[0022] In addition, the sealed space 8 is maintained in a pressurized state or a depressurized state. By maintaining the space 8 in a pressurized state, the insulation performance can be further enhanced and the cooling capacity can be improved, so that the rotating electrical machine 100 can be further miniaturized. Also, by maintaining the space 8 in a depressurized state, the insulation performance can be further enhanced, so that the rotating electrical machine 100 can be further miniaturized. Moreover, even if a discharge occurs by any chance, the duration is short, so the influence of deterioration can be suppressed to a minor level.

[0023] In addition, by enclosing an insulating gas or an insulating liquid in the space 8, the insulation performance can be further enhanced and the cooling capacity can be increased, so that the rotating electrical machine 100 can be further miniaturized. Also, by selecting the gas to be enclosed, the best mix of insulation performance, cooling performance, and price can be considered. Further, when the insulating liquid is hermetically enclosed in the space 8, the liquid tightness can be easily maintained by adjusting the viscosity.

[0024] Also, clay is enclosed in the space 8. Thereby, the insulation performance can be further enhanced and the cooling capacity can be increased, so that the rotating electrical machine 100 can be further miniaturized. Also, since the viscosity is high, the liquid tightness can be easily maintained. Also, by enclosing a sol-gel material in the space 8 instead of clay, the insulation performance can be further enhanced and the cooling capacity can be increased, so that the rotating electrical machine 100 can be further miniaturized. Also, since the viscosity is high, the liquid tightness can be easily maintained and the capillary phenomenon of the stator core 3a can be prevented.

[0025] Embodiment 2. FIG. 3 is a schematic cross-sectional view showing a rotating electrical machine according to Embodiment 2. Note that FIG. 3 shows the upper half with respect to the center line, similar to FIG. 1, and is illustrated with one side omitted. Also, in FIG. 3, components denoted by the same reference numerals as those used for the rotating electrical machine 100 of Embodiment 1 have the same configurations, and their descriptions are omitted. As shown in FIG. 3, in the rotating electrical machine 100 according to Embodiment 2, a partition wall 7 is joined to a housing 1 by friction stir welding (FSW). The partition wall 7 is sealed by friction stir welding, and a joint portion 10 is formed between the housing 1 and the partition wall 7. Thereby, the partition wall 7 can be easily assembled in an airtight manner.

[0026] Note that in FIG. 3, the partition wall 7 is friction stir welded from the outside of the housing 1, but the joining direction is not limited to this. The partition wall 7 may be friction stir welded from the inside of the housing 1 and then the housing 1 may be assembled. Also, in FIG. 3, friction stir welding is performed in the extending direction of the stator core 3a, but friction stir welding may be performed from the circumferential direction of the stator core. Also, in FIG. 3, the partition wall 7 and the housing 1 are directly joined by friction stir welding, but an intermediate member (not shown) made of a metal material such as aluminum or iron may be interposed therebetween. Thereby, even if a pressure difference occurs between the core outer conductive portion 4b side and the housing 1 side (including the outside of the housing 1) and the rotor side, as compared with generally used airtight components such as an O-ring or a liquid packing, the airtightness can be maintained.

[0027] Although the preferred embodiments and the like have been described in detail above, the present invention is not limited to the above-described embodiments and the like, and various modifications and substitutions can be made to the above-described embodiments and the like without departing from the scope described in the claims.

[0028] Hereinafter, aspects of the present disclosure will be summarized as appendices.

[0029] (Appendix 1) Stator core, A coil wound around the stator core and having coil ends protruding from the axial end faces of the stator core. The coil ends are arranged in a sealed space, and the rotating electrical machine is characterized by this. (Appendix 2) A stator arranged in the housing and having the stator core and the coil. A rotor rotatably supported in the stator. The rotating electrical machine according to Appendix 1, wherein the coil ends are arranged in the sealed space so that there is no air exchange between the rotor side and the outside of the housing. (Appendix 3) The rotating electrical machine according to Appendix 1 or Appendix 2, wherein the space is formed by a partition wall. (Appendix 4) The rotating electrical machine according to Appendix 3, wherein a joint portion sealed by friction stir welding is formed in the partition wall. (Appendix 5) The rotating electrical machine according to any one of Appendix 1 to Appendix 4, wherein the space is maintained in a pressurized state or a depressurized state. (Appendix 6) The rotating electrical machine according to any one of Appendix 1 to Appendix 4, wherein an insulating gas or an insulating liquid is enclosed in the space. (Appendix 7) The rotating electrical machine according to any one of Appendix 1 to Appendix 4, wherein clay or a sol-gel material is enclosed in the space.

[0030] Although various exemplary embodiments and examples are described in the present disclosure, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a specific embodiment, but are applicable to the embodiments alone or in various combinations. Accordingly, numerous variations not illustrated are envisioned within the scope of the technology disclosed in this specification. For example, it shall include cases where at least one component is modified, added, or omitted, and further, cases where at least one component is extracted and combined with components of other embodiments.

Description of Reference Numerals

[0031] 1 Housing, 2 Rotor, 3 Stator, 3a Stator Core, 4 Conductive Portion, 4a Conductive Portion Inside Core, 4b Conductive Portion Outside Core, 5 Shaft, 6 Bearing, 7 Partition Wall, 8 Space, 9 Fluid, 10 Joint, 100 Rotating Electric Machine

Claims

1. Stator core, a coil wound around the stator core and having a coil end formed to protrude from an axial end surface of the stator core, The rotating electric machine is characterized in that the coil end is arranged in a sealed space.

2. a stator disposed within the housing and having the stator core and the coil; a rotor rotatably supported within the stator; 2. The rotating electric machine according to claim 1, wherein the coil end is disposed in the sealed space so as to prevent air from being exchanged between the rotor side and the outside of the housing.

3. 3. The rotating electric machine according to claim 1, wherein the space is defined by a partition wall.

4. 4. The rotating electric machine according to claim 3, wherein the partition wall has a joint portion formed by friction stir welding and sealed.

5. 3. The rotating electric machine according to claim 1, wherein the space is maintained in a pressurized or depressurized state.

6. 3. The rotating electric machine according to claim 1, wherein an insulating gas or an insulating liquid is sealed in the space.

7. 3. The rotating electric machine according to claim 1, wherein the space is filled with clay or a sol-gel material.

Images