Rotating electric machine

Abstract

A rotating electric machine including a stator and a rotor housed in a case, wherein: the stator includes a stator core having a plurality of slots, and a plurality of coils that penetrate the slots side by side in the radial direction; spacers are provided between the plurality of coils; and the spacers are melted by a refrigerant flowing into the case.

Description

Rotating electrical machine

[0009]

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

[0002] In Patent Document 1 below, a method of fixing a coil in a slot by inserting a coil and foamed insulating paper into a slot of a stator of a rotating electrical machine and foaming the foamed insulating paper is disclosed.

[0003] Japanese Patent Application Laid-Open No. 2024-47005

[0004] In view of the technique described in Patent Document 1, an object of the present invention is to provide a rotating electrical machine that realizes simplification of an assembly process, improvement of cooling performance, and improvement of motor performance.

[0005] A rotating electrical machine including a stator and a rotor housed in a case, the stator including a stator core having a plurality of slots and a plurality of coils penetrating radially side by side in the slots, a spacer being provided between the plurality of coils, the spacer being melted by a refrigerant flowing into the case.

[0006] It is possible to provide a rotating electrical machine that realizes simplification of an assembly process, improvement of cooling performance, and improvement of motor performance.

[0007] Cross-sectional view for explaining a stator and slots according to an embodiment of the present invention. Explanatory view of a spacer according to an embodiment of the present invention. Explanatory view of a spacer before melting according to an embodiment of the present invention. Explanatory view of the melting process of a spacer according to an embodiment of the present invention. Explanatory view of a spacer according to a modified example of the present invention.

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description and drawings are examples for explaining the present invention, and for clarity of explanation, omissions and simplifications are made as appropriate. The present invention can be implemented in various other forms. Unless otherwise limited, each component may be singular or plural.

[0009] The positions, sizes, shapes, ranges, etc. of the components shown in the drawings may not represent the actual positions, sizes, shapes, ranges, etc. in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, ranges, etc. disclosed in the drawings.

[0010] (One Embodiment and Overall Configuration) (Figure 1) The motor 1 shown in Figure 1(a) has a rotor 2 and a stator 3 on the outer circumference of the rotor 2. The rotor 2 and stator 3 are housed in a motor case (not shown). The stator core 3a that constitutes the stator 3 has a plurality of slots 4 in the circumferential direction. As shown in Figure 1(b), a plurality of coils 5 are arranged radially through each slot 4. Between the coils 5 and the slots 4, there is a foamed insulating paper 6 which is an insulating member that insulates the coils 5 from the stator core 3a, and a foamed adhesive layer 9 which is an insulating member that fixes the coils 5 to the slots 4 (or stator core 3a). In addition, between adjacent coils 5 in the slots 4, there is a flow path 8 which is an air gap through which a coolant flows, and a spacer 7 which forms the flow path 8 between adjacent coils 5 in the slots 4.

[0011] The foamed adhesive layer 9 is a sheet provided between the coil 5 and the slot 4, which foams when heated and hardens when cooled. This allows the coil 5 to be fixed to the stator core 3a.

[0012] The spacer 7 is made of resin. The spacer 7 is applied to the surface of the coil 5 and hardens, becoming an integral part of the coil 5. Furthermore, by ensuring that the spacer 7 is not provided on at least some of the circumferential surfaces of the coil 5, the foamed adhesive layer 9 that expands during heating can adhere to the coil 5, and the coil 5 is fixed to the stator core 3a. In this case, since the spacer 7 is not provided on either the left or right circumferential surface of the coil 5, the coolant flowing through the flow path 8 comes into contact with at least one side of the coil 5, thus ensuring the minimum necessary cooling performance of the coil 5.

[0013] Here, a coolant for cooling the motor 1 flows into the motor 1 case from the outside and flows through the passage 8 of the stator core 3a. This coolant is a cooling oil such as ATF (Automatic Transmission Fluid). The spacer 7 is made of a resin material that melts when exposed to the coolant. Therefore, when such a coolant flows into the passage 8 of the slot 4, the spacer 7 melts (is removed). Note that the coolant flowing through the passage 8 is not limited to ATF; any cooling oil will suffice.

[0014] (Figure 2) As described above, the spacer 7 is provided on the surfaces of a pair of opposing coils 5. When the spacer 7 is sandwiched between adjacent coils 5, one surface becomes the assembly load receiving surface 7a, and the other surface facing the assembly load receiving surface 7a becomes the adhesive surface 7b. Thus, the shape of the spacer 7 formed between adjacent coils 5 is such that it will not be damaged by the load applied to the coils 5 during the assembly process before melting in the refrigerant.

[0015] (Figure 3) Before being melted by the refrigerant, the spacer 7 is positioned to fill the gaps between adjacent coils 5 in the slot 4, so that the flow path area 8 is narrowed. This arrangement of spacer 7 creates a predetermined gap between adjacent coils 5 in the slot 4. The spacer 7 is coated and hardened on the surface of each coil 5 to be inserted into the slot 4 before the slot 4 is inserted, so that it becomes one with the multiple coils 5 in the slot 4.

[0016] (Figure 4) As the refrigerant circulates within the motor 1 case and flows into the flow path 8 in the slot 4, the spacer 7 melts due to the refrigerant. In this way, the spacer 7 is removed by melting between adjacent coils 5, and the area of ​​the flow path 8 is expanded. With this configuration of the spacer 7, the contact area between the spacer 7 and the coil 5 is expanded during the assembly process, suppressing the concentration of load on the spacer 7, and there is no concern that the spacer 7 will be damaged or fall off due to coil bending and twisting during the assembly process. Furthermore, when the spacer 7 melts, the area of ​​the flow path 8 is expanded, increasing the contact area between the coil 5 and the refrigerant, reducing pressure loss, and improving the flow velocity of the refrigerant in the flow path 8. As a result, the assembly process is simplified and the cooling performance of the motor is improved. In addition, considering that the spacer 7 melts due to the refrigerant, it can also contribute to expanding the cross-sectional area of ​​the coil 5.

[0017] Furthermore, since the spacer 7 does not need to be completely melted in the refrigerant, for example, the spacer 7 may be formed by mixing a material that melts in the refrigerant with a material that does not melt in the refrigerant. As shown in Figure 4, the spacer 7 may be melted after the refrigerant flows through the flow path 8, leaving a minimum amount of spacer as a partial spacer 7c. This ensures the strength of the spacer 7 during the assembly process, while also ensuring the formation of the flow path 8 by removing most of the spacer 7 when the refrigerant flows through it, thereby increasing cooling performance. In addition, compared to the case where the spacer 7 is completely melted in the refrigerant, there is no need to consider or modify the shape of the coil 5, thus reducing the cost of the coil 5. Motor performance can also be improved. Moreover, since it is sufficient for the spacer 7 to be formed only in the necessary parts on the coil 5, it does not affect the bending or twisting processes of the coil 5.

[0018] Furthermore, both ends of the coil 5 within the slot 4 are areas that are prone to stress during bending in the assembly process. Therefore, spacers 7 are formed at least at both ends of the coil 5 within the slot 4.

[0019] This document compares the conventional problem with one embodiment of the present invention. Conventional resin spacers 7 are generally inserted as a separate component between the coil 5 and the slot 4, which increases the assembly process. Furthermore, when assembled in this manner, friction occurs between the spacer 7 and the coil 5, which can damage the coating of the coil 5 and reduce insulation reliability. In addition, the spacer 7 may be damaged or fall off due to friction with the coil 5, resulting in poorly formed gaps between the coils 5 in the slot 4 and a decrease in cooling performance. In other conventional configurations, such as using a springy spacer 7 to press and fix the coil 5 into the slot 4, the coating of the coil 5 is damaged by motor vibrations and the insertion of the spacer 7, resulting in a decrease in dielectric strength. Furthermore, when the gap between the coils 5 is used as a flow path, the springy spacer 7 increases pressure loss, resulting in a decrease in cooling performance.

[0020] However, as mentioned above, in one embodiment of the present invention, the spacer 7 and the coil 5 are integrated, the coil 5 is fixed by a foamed adhesive layer 9, the spacer 7 forms a gap between adjacent coils 5, and the spacer 7 melts into the refrigerant. As a result, friction between the coil 5 and the spacer 7 does not occur due to vibrations during motor operation, so there is no concern that the insulating coating of the coil 5 will be damaged. In addition, the spacer 7 can obtain both a shape that ensures cooling performance and the strength required during the assembly process, thus ensuring reliability.

[0021] Furthermore, in one embodiment of the present invention, since the spacer 7 and the coil 5 are integrated, the same assembly process as in the conventional method can be realized. Also, because the spacer 7 has a large contact surface with the coil 5, there is no damage to the spacer 7 during the assembly process, thus suppressing defects in the formation of gaps between adjacent coils 5 and ensuring a uniform arrangement of coils 5 in the slot 4.

[0022] (Modified Version) (Figure 5) A modified version of the present invention will be described. As shown in Figure 5(a), in the coil 5 within the slot 4, spacers 7 with a large contact area with the coil 5 may be provided at both ends, and a partial spacer 7c with a small contact area with the coil 5 may be provided at the central part. By implementing this configuration of spacers 7 with different axial directions on the coil 5 before the assembly process, the spacers 7 can withstand the load generated during the bending and twisting processes of the coil 5 that occur near both ends of the coil 5 during the assembly process, thereby improving manufacturability. Furthermore, by reducing the spacer 7 in the central part of the coil 5, cost reduction and improvement of the cycle time from coating time to curing time can be achieved.

[0023] Furthermore, as shown in Figure 5(b), spacers 7 may be provided not only between adjacent coils 5, but also between the coil 5 and the slot 4 (stator core 3a). Note that the foamed insulating paper 6 provided in the slot 4 as shown in Figures 1(b) and 3 is omitted from the illustration. The spacers 7 are provided either between adjacent coils 5, or between the coil 5 and the slot 4, or both. This suppresses foaming of the foamed adhesive layer 9 provided in the same area as the spacer 7 between the coil 5 and the stator core 3a, and facilitates the formation of a flow path 8 between the coil 5 and the stator core 3a. In addition, fixing varnish in the slot 4 becomes unnecessary. Note that spacers 7 may be provided on either the radial side surface or the circumferential side surface, or both, of the coil 5, unless they are provided on at least some of the circumferential surfaces of the coil 5.

[0024] As shown in Figure 5(b), the spacer 7 provided between the coil 5 and the stator core 3a may be configured as shown in Figure 5(c), for example, if the coil 5 is rectangular, spacer 7 may be provided at each of its four corners. This prevents foam from the foam insulating paper 6 from entering between adjacent coils 5. In addition, such spacer 7 may be provided at either the upper two corners or the lower two corners of the coil 5 as shown in Figure 5(c).

[0025] It should be noted that the present invention is not limited to the embodiments described above, and various modifications and combinations of other configurations can be made without departing from the spirit of the invention. Furthermore, the present invention is not limited to having all the configurations described in the embodiments described above, and may also include configurations in which some of those configurations are omitted.

[0026] 1. Motor 2. Rotor 3. Stator 3a. Stator core 4. Slot 5. Coil 6. Foamed insulating paper 7. Spacer 7a. Assembly load bearing surface 7b. Adhesive surface 7c. Partial spacer 8. Flow path 9. Foamed adhesive layer

Claims

1. A rotating electric machine comprising a stator and a rotor housed in a case, wherein the stator comprises a stator core having a plurality of slots and a plurality of coils passing through the slots in a radially aligned manner, spacers are provided between the plurality of coils, and the spacers are melted by a coolant flowing into the case.

2. A rotating electric machine according to claim 1, wherein the spacer is provided on the surfaces of a pair of coils facing each other.

3. A rotating electric machine according to claim 2, wherein the spacer is made of resin and is coated and cured on the surface of the coil.

4. A rotating electric machine according to claim 2, wherein the spacer is not provided on at least some of the circumferential surfaces of the coil.

5. A rotating electric machine according to claim 4, wherein a sheet for fixing the coil to the stator core is provided between the coil and the slot.

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