Stator, rotary electric machine, and method for assembling rotary electric machine

Abstract

This stator is provided on the outer periphery of a rotor, and comprises: a plurality of teeth (9) that are arranged in a circumferential direction about an axis; a slot (11) that is formed between each pair of teeth (9) adjacent to each other and has a housing space for a coil (10) wound around each tooth (9); and a wedge (18) that is inserted into an opening (11a) of the slot (11) opening inward in a radial direction. The wedge (18) is formed in a plate shape that can be bent so as to reduce the width of the wedge (18) in the circumferential direction. The paired teeth (9, 9) include side surfaces (15, 15) facing each other. The side surfaces (15, 15) have engagement parts (16, 16) that engage with both end parts (23, 23) of the wedge (18) in the circumferential direction and restrict movement of the wedge (18) inward in the radial direction.

Description

Stator, rotating electric machine, and method for assembling rotating electric machine

[0001] The present disclosure relates to a stator for a rotating electric machine, a rotating electric machine including the stator, and a method for assembling a rotating electric machine.

[0002] Patent Document 1 discloses a coil insertion device. This device uses a rod-shaped blade to insert a coil into a slot in a stator, and then uses a wedge pusher to insert a wedge into the slot. Both the coil and the wedge are inserted into the slot from the axial direction of the stator. The wedge inserted into the slot is inserted in a position that blocks the opening of the slot, which opens radially inward, preventing the coil from jumping out of the opening and providing electrical insulation between the coil and the stator.

[0003] Japanese Patent Application Laid-Open No. 2015-204647

[0004] As described above, the wedge is inserted into the slot from the axial direction of the stator. At this time, the contents such as a coil are already inserted into the slot, and the space left in the slot is relatively narrow. Therefore, when the wedge is inserted into such a narrow space, the wedge is likely to rub against the contents, which may cause scratches on the contents.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide a stator for a rotating electric machine that allows for easy attachment of wedges to slots, a rotating electric machine equipped with such a stator, and a method for assembling such a rotating electric machine.

[0006] A stator according to a first aspect of the present disclosure is provided on the outer periphery of a rotor of a rotating electric machine, the stator including a plurality of teeth arranged in a circumferential direction about an axis, slots formed between adjacent pairs of the teeth and each having a space for accommodating a coil wound around each of the teeth, and wedges inserted into openings of the slots that open radially inward, the wedges being formed in a flexible plate shape that can reduce the width of the wedge in the circumferential direction, the pairs of teeth including opposing side surfaces having engaging portions that engage with both ends of the wedge in the circumferential direction and restrict radially inward movement of the wedge.

[0007] The stator may further include a seal member disposed radially outward of the wedge within the slot and in contact with the side surfaces of the pair of teeth. The stator may further include a reinforcing portion supported by the seal member and facing the accommodating space for the coil. The reinforcing portion may have at least one groove formed therein that opens toward the accommodating space for the coil and extends in a direction parallel to the axis. The wedge may include a pair of side portions extending radially inward such that the distance between them increases, and the seal member may include a main portion facing the accommodating space and a pair of legs positioned from the main portion between the side surfaces of the pair of teeth and the pair of side portions.

[0008] A rotating electric machine according to a second aspect of the present disclosure includes the stator according to the first aspect.

[0009] According to a third aspect of the present disclosure, a method for assembling a rotating electric machine having a stator provided on the outer periphery of a rotor includes a plurality of teeth arranged circumferentially around an axis, and slots formed between each pair of adjacent teeth and having a space for accommodating a coil wound around each of the teeth, the method including: inserting a sealing member and a reinforcing portion into the slot from the axial direction with the coil accommodated in the slot; and inserting a wedge into an opening of the slot that opens radially inward from the radially inner side of the opening.

[0010] According to the present disclosure, it is possible to provide a stator for a rotating electric machine that allows easy attachment of wedges to slots, a rotating electric machine including the stator, and a method for assembling a rotating electric machine.

[0011] FIG. 1 is a diagram illustrating an example of a rotating electric machine according to an embodiment of the present disclosure. FIG. 2 is a partially enlarged view of a stator as viewed from the axial direction. FIG. 3 is a diagram illustrating the tip of a tooth and its surroundings as viewed from the axial direction. FIG. 4 is a diagram of a wedge as viewed from the axial direction. FIG. 5A is a diagram of a seal member and a reinforcing portion as viewed from the axial direction. FIG. 5B is a diagram of a modified seal member as viewed from the axial direction. FIG. 6A is one of diagrams illustrating the step-by-step installation of a wedge, a seal member, and a reinforcing portion into a slot. FIG. 6B is one of diagrams illustrating the step-by-step installation of a wedge, a seal member, and a reinforcing portion into a slot. FIG. 6C is one of diagrams illustrating the step-by-step installation of a wedge, a seal member, and a reinforcing portion into a slot.

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In addition, common parts in the drawings are given the same reference numerals, and duplicated explanations will be omitted.

[0013] First, a rotating electric machine 1 according to this embodiment will be described. For ease of explanation, the direction in which the axis 2 extends is defined as the axial direction AD. The axis 2 is the central axis of rotation of the shaft 5 and rotor 3, and the central axis of the radially arranged teeth 9. In addition, a circumferential direction CD and a radial direction RD are defined, each centered on the axis 2. Note that "width" refers to the length between two points in the circumferential direction CD (or its tangential direction).

[0014] FIG. 1 is a diagram showing an example of a rotating electric machine 1 according to this embodiment. The rotating electric machine 1 is a generator or an electric motor, and includes a rotor 3 and a stator 4 provided on the outer periphery of the rotor 3. The rotor 3 is attached to a shaft 5 extending in an axial direction AD. The rotor 3, the stator 4, and the shaft 5 are arranged concentrically with respect to an axis 2. The shaft 5 is rotatably supported by bearings 6, 6. The bearings 6, 6 are attached to a housing 7.

[0015] The stator 4 includes a core (yoke) 8 supported by a housing 7, teeth (magnetic poles) 9 (see FIG. 2) extending radially inward from the core 8, and coils 10 wound around the teeth 9.

[0016] The coil 10 is housed in a slot 11 (see FIG. 2) formed between the teeth 9, 9. A portion of the coil 10 is folded back and exposed as coil ends 10a, 10b on both sides of the core 8 in the axial direction AD.

[0017] The housing 7 has accommodation chambers 7a and 7b for the coil ends. The coil end 10a is accommodated in the accommodation chamber 7a, and the coil end 10b is accommodated in the accommodation chamber 7b. The accommodation chambers 7a and 7b communicate with each other via a flow passage 12 (see FIG. 2) formed in the slot 11.

[0018] The rotating electric machine 1 according to this embodiment is cooled by a cooling device 13 that uses a refrigerant CL. The cooling device 13 includes a pump (not shown) that pressure-feeds the refrigerant CL to the rotating electric machine 1, a heat exchanger that cools the refrigerant CL, and a valve that controls the amount of refrigerant CL supplied. The refrigerant CL is a liquid such as lubricating oil or insulating oil.

[0019] As shown in FIG. 1, the cooling device 13 supplies the refrigerant CL to the accommodation chamber 7a. The refrigerant CL supplied to the accommodation chamber 7a flows into the accommodation chamber 7b via the flow path 12 (see FIG. 2). The refrigerant CL then returns to the cooling device 13. As the refrigerant CL flows from the accommodation chamber 7a to the accommodation chamber 7b, it cools at least the coil 10. The temperature of the refrigerant rises due to heat exchange accompanying this cooling. The high-temperature refrigerant is cooled by a heat exchanger in the cooling device 13 and is supplied again to the accommodation chamber 7a.

[0020] Next, the stator 4 according to this embodiment will be described. Fig. 2 is a partially enlarged view of the stator 4 as viewed from the axial direction AD, showing the periphery of the tip end 14 of the tooth 9. Fig. 3 is a view showing the periphery of the tip end 14 of the tooth 9 as viewed from the axial direction AD. As shown in Fig. 2, the stator 4 includes a plurality of teeth 9 and a plurality of slots 11.

[0021] The teeth 9 are so-called magnetic poles. The teeth 9 extend a predetermined length radially inward from the core 8 and are arranged in the circumferential direction CD. Of the multiple teeth 9, each pair of adjacent teeth 9 forms a slot 11 between the pair.

[0022] 2 and 3 , the teeth 9 have side surfaces 15, 15. The side surfaces 15, 15 are formed on both sides of the teeth 9 in the circumferential direction CD and also serve as the inner surfaces of the slots 11. Each side surface 15 has an engaging portion 16 at a position where the opening 11a of the slot 11 is formed. In other words, adjacent (paired) teeth 9, 9 include side surfaces 15, 15 facing each other, and each side surface 15 has the engaging portion 16.

[0023] The engaging portion 16 restricts the movement of the wedge 18 radially inward. To this end, the engaging portion 16 has, for example, an abutment surface 16a. The abutment surface 16a is a small-width flat surface that faces radially outward and extends in the axial direction AD. The abutment surface 16a intersects with the side surface 15 at a predetermined angle (e.g., 90°) and forms a step on the side surface 15. This step narrows the width W1 of the opening 11a of the slot 11 compared to the width W2 of the slot 11 at the back (i.e., at a position radially outward from the opening 11a). Therefore, the width of the tooth 9 is wider radially inward than radially outward, with the step formed by the abutment surface 16a as the boundary.

[0024] The slots 11 have spaces 17 for accommodating the coils 10 wound around the respective teeth 9. The slots 11 also have openings 11a that open radially inward. The tip ends 14 of adjacent teeth 9 are spaced apart from each other in the circumferential direction CD, thereby forming the openings 11a. The openings 11a function as insertion ports for wedges 18.

[0025] The stator 4 further includes a wedge 18, a seal member 19, and a reinforcing portion 20. Of these three members, the wedge 18 is located furthest radially inward. The seal member 19 and the reinforcing portion 20 are located between the coil 10 and the wedge 18. The seal member 19 and the reinforcing portion 20 are inserted into the slot 11, for example, from the axial direction AD. On the other hand, the wedge 18 is inserted into the slot 11 from the radial direction RD. That is, the wedge 18 is inserted into the slot 11 through the opening 11a, and prevents the coil 10, the seal member 19, and the reinforcing portion 20 from protruding radially inward.

[0026] FIG. 4 is a view of the wedge 18 as seen from the axial direction AD. The wedge 18 is a metal plate-shaped member extending in the axial direction AD. Therefore, compared to conventional wedges made of resin, it has high mechanical strength and heat resistance. Furthermore, as will be described later, its relatively thin thickness also helps to reduce eddy current loss. Such a wedge 18 is inserted into the opening 11a of the slot to close the opening 11a. However, the material of the wedge 18 is not limited to metal as long as it meets the above requirements.

[0027] The wedge 18 has a cross-sectional shape that curves radially outward. For example, the wedge 18 includes a planar intermediate portion 21 and a pair of side portions 22, 22. Each side portion 22 includes an end portion (edge ​​portion) 23 of the wedge 18. The pair of side portions 22, 22 are provided on both sides of the intermediate portion 21 in the circumferential direction CD and extend so that the distance between them increases radially inward. In this case, the wedge 18 has a generally U-shaped cross section that opens radially inward as a whole.

[0028] The thickness of the wedge 18 is set to a value (e.g., 0.3 mm) that allows the wedge 18 to bend so as to reduce its width. When stress that reduces the width of the wedge 18 is applied to the wedge 18, the location that actually bends depends on the cross-sectional shape or dimensions of the wedge 18. For example, if the wedge 18 includes a middle portion 21 and a pair of side portions 22, 22 as shown in FIG. 4, the entire wedge 18 may bend, or one of the middle portion 21 and the pair of side portions 22, 22 may bend. Alternatively, like a hinge, the connection portion between the middle portion 21 and each side portion 22 may bend more than the other portions.

[0029] The intermediate portion 21 is generally perpendicular to the radial direction and extends in the axial direction. The pair of side portions 22 also extend such that the distance between them increases as they extend radially inward. The intermediate portion 21 and each side surface 15 are both formed flat.

[0030] The cross-sectional shape of the wedge 18 is not limited to a generally U-shape. For example, the cross-sectional shape of the wedge 18 may be a shape that is curved radially outward. In either case, the pair of end portions 23, 23 engage with the engaging portion 16, restricting radially inward movement of the wedge 18.

[0031] The width W3 of the wedge 18 when not subjected to an external force (i.e., when not deflected) is slightly larger than the width W1 (see FIG. 3) of the opening 11a of the slot 11. For example, the width W3 of the wedge 18 is slightly larger than the width between the abutment surfaces 16a, 16a provided on the side surfaces 15, 15 of the adjacent teeth 9, 9 that face each other across the slot 11. However, the wedge 18 can deflect so that the width W3 becomes smaller than the width W1 of the opening 11a.

[0032] 5A is a view of the seal member 19 and the reinforcing portion 20 as viewed from the axial direction AD. The seal member 19 is provided radially outward of the wedge 18 within the slot 11. The seal member 19 also contacts the side surfaces 15, 15 of the adjacent (i.e., paired) teeth 9, 9.

[0033] The seal member 19 is an elastic member that stretches in the axial direction AD. The seal member 19 is formed of an elastomer such as fluororubber. As shown in Fig. 5A, the seal member 19 includes a main body 25 and a pair of legs 26, 26. The main body 25 is provided in a position facing the accommodation space 17 (see Fig. 3) for the coil 10. On the other hand, the pair of legs 26, 26 are provided in a position facing the wedge 18.

[0034] The main body 25 has a generally rectangular cross section. The main body 25 has an upper surface 25 a facing radially outward, a lower surface 25 b facing radially inward, and two side surfaces 25 c, 25 c connecting both ends of the upper surface 25 a and the lower surface 25 b in the circumferential direction CD. The maximum width between the two side surfaces 25 c, 25 c defines the width W4 (or W6) of the seal member 19.

[0035] When the seal member 19 is installed in the slot 11, the upper surface 25a of the main body portion 25 faces the coil 10, and the lower surface 25b of the main body portion 25 faces the wedge 18 (e.g., the intermediate portion 21). Also, the two side surfaces 25c, 25c of the main body portion 25 each face the side surface 15 of the corresponding tooth 9.

[0036] The pair of legs 26, 26 are formed integrally with the main body 25. The pair of legs 26, 26 extend from both sides of the main body 25 in the circumferential direction CD toward the wedge 18. The pair of legs 26, 26 are located between the side surfaces 15, 15 of the adjacent (i.e., paired) teeth 9, 9 and the pair of side surfaces 22, 22 of the wedge 18.

[0037] The width W4 of the seal member 19 is slightly smaller than the width W5 (see FIG. 2) of the slot 11 at a position where the seal member 19 can be positioned. Therefore, the seal member 19 is movable in the radial direction RD and the axial direction AD within the slot 11. That is, the seal member 19 can be inserted into the slot 11 at a position away from the coil 10 without being interfered with by the side surface 15 of the tooth 9 (see FIG. 6A).

[0038] However, as described below, the pair of legs 26, 26 are pressed by the pair of side portions 22, 22 of the wedge 18 toward the side surfaces 15, 15 of the adjacent (i.e., paired) teeth 9, 9. This pressing causes the pair of legs 26, 26 to elastically deform, and the seal member 19 to come into close contact with each side surface 15. As a result, the accommodating space 17 for the coil 10 is surrounded without any gaps (i.e., a closed region) by the inner surface of the slot 11 and the seal member 19 on a cross section perpendicular to the axial direction AD, and communicates with the accommodating chambers 7 a and 7 b. In other words, this space functions as a flow path 12 for the refrigerant CL, and the refrigerant CL flowing through the flow path 12 cools at least the coil 10.

[0039] 5B is a view of a modified example of the seal member 19 as viewed from the axial direction AD. The seal member 19 shown in FIG. 5B does not have a pair of legs 26. Instead, the width (maximum width) W6 of the seal member 19 is larger than the width W5 of the slot 11 at the location where the seal member 19 is installed.

[0040] As described above, the seal member 19 has elasticity. Therefore, when the seal member 19 is inserted into the slot 11, at least a portion of the side surface 15 of the seal member 19 comes into contact with the side surface 15 of the corresponding tooth 9. When attaching the seal member 19 to the slot 11, for example, a jig (not shown) having a pair of blades is used. The pair of blades clamp the side surfaces 15, 15 of the seal member 19, reducing the width W6 to be smaller than the width W5. While maintaining this state, the seal member 19 is inserted into the slot 11 together with the pair of blades, and then only the pair of blades retract from the slot 11. By this operation, the seal member 19 can be attached to the slot 11.

[0041] The reinforcing portion 20 is a rectangular rod-shaped member and is supported by the sealing member 19. The reinforcing portion 20 includes an exposed portion 28 that is exposed from the sealing member 19 to the housing space 17, and a root portion 29 that is embedded in the sealing member 19. The exposed portion 28 has an upper surface 20a that faces the housing space 17 for the coil 10.

[0042] The reinforcing portion 20 is formed of a material that is harder than the sealing member 19 and has neither magnetic nor conductive properties. Such a material is, for example, ceramic. The reinforcing portion 20 adheres to the sealing member 19 and suppresses excessive deformation of the sealing member 19. For example, when the sealing member 19 is made of fluororubber, the sealing member 19 is adhered to the reinforcing portion 20 by vulcanization adhesion.

[0043] When the coolant CL flows through the flow path 12, the pressure inside the flow path 12 is increased by a pump (not shown) of the cooling device 13. On the other hand, the reinforcing portion 20 is provided at a position facing the flow path 12. Therefore, the reinforcing portion 20 receives the pressure inside the flow path 12 that the seal member 19 would otherwise receive, and suppresses excessive deformation of the seal member 19.

[0044] At least one groove 30 may be formed in the reinforcing portion 20, the groove 30 opening toward the accommodation space 17 of the coil 10 and extending in the axial direction AD. For example, as shown in FIG. 5A , one groove 30 is formed in the exposed portion 28.

[0045] As described above, a flow path 12 for the refrigerant CL is formed between the seal member 19 and the coil 10. When at least one groove 30 is formed in the reinforcing portion 20, the flow path 12 can be secured even if the distance between the seal member 19 and the coil 10 is only approximately the thickness of the exposed portion 28. For example, the flow path 12 can be secured even if the upper surface 20a of the reinforcing portion 20 is in contact with the coil 10.

[0046] 5A, the groove 30 may be divided into a plurality of grooves extending parallel to each other. In this case, the contact area of ​​the reinforcing portion 20 with the refrigerant CL increases, and the cooling efficiency of the reinforcing portion 20 can be improved.

[0047] Next, an assembly method according to this embodiment will be described. Specifically, the installation of the wedge 18, the seal member 19, and the reinforcing portion 20 into the slot 11 will be described. Figures 6A to 6C are diagrams showing the steps of installing these members into the slot 11. Note that the wedge shown in these figures is the wedge 18 shown in Figure 4, and the seal member is the seal member 19 shown in Figure 5A. It is also assumed that the coil 10 has been previously housed in the housing space 17 (see Figure 3).

[0048] First, the seal member 19 and the reinforcing portion 20 are inserted into the slot 11 from the axial direction AD. The width W4 of the seal member 19 (see FIG. 5A) is smaller than the width W5 of the slot 11 (see FIG. 2). Therefore, as shown in FIG. 6A, the seal member 19 and the reinforcing portion 20 are inserted into the slot 11 at a position sufficiently separated from the coil 10.

[0049] Next, the wedge 18 is inserted into the opening 11a of the slot 11 from the radially inner side of the opening 11a. The width W3 (see FIG. 4) of the wedge 18 is greater than the width W1 (see FIG. 3) of the opening 11a of the slot 11. Therefore, as shown in FIG. 6B , the wedge 18 is bent radially outward so that the width W3 is reduced until the end 23 of the wedge 18 reaches the engagement portion 16.

[0050] As the wedge 18 is inserted into the opening, it contacts the lower surface 25b of the seal member 19, bringing the seal member 19 and the reinforcing portion 20 closer to the coil 10. As the wedge 18 is further inserted, the end 23 of the wedge 18 reaches the engagement portion 16. When the end 23 of the wedge 18 reaches the engagement portion 16, for example, when the end 23 of the wedge 18 passes the abutment surface 16a, the elastic force of the wedge 18 causes the pair of side portions 22, 22 of the wedge 18 to open slightly (see FIG. 6C ). This allows the abutment surface 16a to abut against the end 23 of the wedge 18 from the radially inward direction, restricting the wedge 18 from moving radially inward. Furthermore, for example, the opening 11a is blocked by the wedge 18. In this way, the wedge 18 can be easily inserted into the slot 11 while avoiding unnecessary collision with other components.

[0051] On the other hand, the distance between the wedge 18 engaged with the engaging portion 16 and the coil 10 is approximately equal to the sum of the thicknesses of the main body portion 25 and the exposed portion 28 of the reinforcing portion 20 along the radial direction RD. Therefore, when the wedge 18 engages with the engaging portion 16, the pair of legs 26, 26 are pressed by the pair of side portions 22, 22 of the wedge 18 toward the side surfaces 15, 15 of the adjacent (i.e., paired) teeth 9, 9.

[0052] This pressure causes the pair of legs 26, 26 to elastically deform, and the seal member 19 comes into close contact with each side surface 15. As a result, the accommodation space 17 for the coil 10 is surrounded without any gaps by the inner surface of the slot 11 and the seal member 19 on a cross section perpendicular to the axial direction AD (i.e., it is a closed region), and communicates with the accommodation chambers 7a and 7b. That is, this space functions as a flow path 12 for the refrigerant CL.

[0053] While the coolant CL flows through the flow path 12, the pressure inside the flow path 12 is increased by a pump (not shown) of the cooling device 13. Therefore, the seal member 19 is subjected to this pressure and may move radially inward. However, a wedge 18 is provided radially inward of the seal member 19, and even when the seal member 19 moves radially inward, the lower surface 25b of the seal member 19 comes into contact with the wedge 18. Meanwhile, the wedge 18 is engaged with the engaging portion 16, restricting its movement radially inward. Therefore, the seal member 19 is supported by the wedge 18, preventing it from falling out of the slot 11.

[0054] Note that the reinforcing portion 20 may be omitted depending on the pressure inside the flow path 12 and the hardness of the sealing member 19. Furthermore, if sealing by the sealing member 19 is not required or if the refrigerant CL is not required, the reinforcing portion 20 and the sealing member 19 may be omitted. In this case, the cooling device 13 in FIG. 1 is also unnecessary. Even in this case, the wedge 18 prevents the contents, such as the coil 10, from spilling out. Furthermore, because the wedge 18 is inserted from the opening 11a of the slot 11, it is possible to prevent scratches on the coil, which is a concern when the wedge is inserted into the slot from the axial direction.

[0055] The present disclosure is not limited to the above-described embodiments, but is defined by the claims, and includes all modifications within the meaning and scope equivalent to the claims.

Claims

1. A stator for a rotating electric machine provided on the outer periphery of a rotor, comprising: a plurality of teeth arranged in a circumferential direction centered on an axis; slots formed between each pair of adjacent teeth and having space to accommodate coils wound around each of the teeth; and wedges inserted into openings of the slots that open radially inward, wherein the wedges are formed in a plate shape that can bend so as to reduce the width of the wedge in the circumferential direction, and the teeth forming each pair include side surfaces facing each other, and the side surfaces have engaging portions that engage with both ends of the wedge in the circumferential direction and restrict movement of the wedge radially inward.

2. The stator according to claim 1, further comprising a seal member provided radially outward from said wedge within said slot and in contact with said side surfaces of said pair of said teeth.

3. The stator according to claim 2, further comprising a reinforcing portion supported by said seal member and facing said coil accommodation space.

4. The stator according to claim 3, wherein the reinforcing portion is formed with at least one groove that opens toward the coil accommodation space and extends in a direction parallel to the axis.

5. A stator as described in claim 2, wherein the wedge includes a pair of side portions extending so that the distance between them increases as they extend radially inward, and the seal member includes a main body portion facing the accommodating space, and a pair of legs positioned from the main body portion between the side surfaces of the pair of teeth and the pair of side portions.

6. A rotating electric machine comprising a stator according to any one of claims 1 to 5.

7. A method for assembling a rotating electric machine having a stator provided on the outer periphery of a rotor, the stator including a plurality of teeth arranged in a circumferential direction centered on an axis, and slots formed between each pair of adjacent teeth and having a space for accommodating a coil wound around each of the teeth, comprising the steps of: inserting a sealing member and a reinforcing part into the slot from the axial direction with the coil accommodated in the slot; and inserting a wedge into an opening of the slot that opens radially inward from the radially inner side of the opening.

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