Stator

Abstract

To enable a suppression of an insulation damage in an inner region of a radial direction of an insulation ring as compared with the conventional one.SOLUTION: A plurality of coil segments 30 is inserted into a plurality of slots 23. An insulation ring 40 covers each coil end 34, respectively. A pair of coil ends 34 is connected thereto, and it becomes a pair of coil ends 36. A plurality of rows 38 of the pair of coil ends 36 arranged radially is coated with the insulation ring 40. The insulation ring 40 comprises: a plurality of projections 42; and a plurality of groove parts. Each projection 42 covers the row 38 of the coil end. The groove part is arranged between the rows 38 and 38 of the adjacent coils. At least one of the plurality of groove parts is an inclination groove part 44. A depth of each groove of the inclination groove part 44 becomes narrow toward an inner side from an outer side of a radial direction of a stator core 20. Also, a bottom wall 45 of the inclination groove part 44 becomes thick toward the inner side from the outer side of the radial direction of the stator core 20.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] This specification discloses a stator for a rotating electric machine. In particular, this specification relates to a shape of an insulating ring that covers a coil end of the stator. [Background technology]

[0002] The rotating electric machine includes a stator. The stator includes a stator core and a coil. The stator core is a cylindrical component. A slot is formed on the radially inner side of the stator core. A plurality of slots are arranged circumferentially.

[0003] Coils are inserted into the slots. Instead of a single coil being wound around the stator core from start to finish, multiple coil segments may be used. A coil segment is a wiring component that is roughly U-shaped. The pair of coil segments are made conductive by welding the coil ends of one coil segment to the other coil segment.

[0004] The surface of the coil segment is coated with insulating resin or the like. However, in order to electrically connect the coil ends of a pair of coil segments, the conductors of the coil ends are exposed. After welding of all pairs of coil ends in the stator core is completed, the coil ends are covered with insulating rings. The insulating rings are disclosed in, for example, Patent Documents 1 and 2.

[0005] The slots of the stator core are arranged circumferentially. Therefore, when the coil segments are inserted into the respective slots, the coil ends are arranged circumferentially. These coil ends are covered with insulating rings. The insulating rings are obtained by molding insulating resin into a hollow ring shape.

[0006] To avoid unintended conduction, the pair of coil ends is separated from the surrounding coil ends. For example, multiple pairs of coil ends are arranged at intervals along the radial direction of the stator core. Further, rows of coil end pairs are arranged at intervals along the circumferential direction.

[0007] Patent Document 1 discloses an insulating ring with a concave-convex shape. The insulating ring has ridges at the portions that cover the coil ends. Furthermore, the insulating ring has grooves at the gaps between the coil ends, and the ridges and grooves extend along the radial direction of the stator core. The ridges and grooves are also arranged radially. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2017-189058 A [Patent Document 2] JP 2022-174650 A Summary of the Invention [Problem to be solved by the invention]

[0009] Incidentally, as the protrusions are arranged radially, the grooves disposed between adjacent protrusions have a width that narrows toward the radial center of the stator core.

[0010] Here, the coil generates heat while the rotating electric machine is in operation. As a result, the insulating ring becomes hot. At this time, the resin in the insulating ring expands. As a result, compressive stress occurs in the groove. Also, when the rotating electric machine is not in operation, the resin between the coils contracts as the temperature of the insulating ring drops. As a result, tensile stress occurs in the groove.

[0011] In this way, the grooves are subject to so-called thermal fatigue. In particular, the inner region of the grooves along the radial direction of the stator core has a smaller groove width than the outer region in the radial direction. In other words, load distribution during expansion and compression is difficult. Therefore, cracks due to thermal fatigue may occur in the inner region of the grooves. For example, if the cracks reach the coil ends, insulation breakdown may occur.

[0012] Therefore, in this embodiment, a stator is disclosed that can suppress dielectric breakdown in the radially inner region of the insulating ring more than in the conventional case. [Means for solving the problem]

[0013] The stator disclosed in this embodiment includes a stator core, a plurality of coil segments, and an insulating ring. The stator core is a cylindrical part. A plurality of slots are arranged on the radial inside of the stator core. The plurality of slots are arranged circumferentially. The plurality of coil segments are inserted into the plurality of slots. The insulating ring covers each coil end. The coil end is an end of the coil segment. A pair of coil ends is connected to each other to form a coil end pair. A plurality of pairs of coil ends are arranged along the radial direction of the stator core. A plurality of rows of coil end pairs are radially arranged at intervals along the circumferential direction of the stator core. The plurality of rows of coil end pairs arranged radially are covered by the insulating ring. The insulating ring includes a plurality of ridges and a plurality of grooves. The ridges cover the rows of coil end pairs. The grooves are arranged between adjacent rows of coil end pairs. At least a portion of the plurality of grooves is an inclined groove. The inclined groove portion has a groove depth that becomes shallower from the outer side toward the inner side in the radial direction of the stator core. Here, the inclined groove portion has a bottom wall that becomes thicker from the outer side toward the inner side in the radial direction of the stator core.

[0014] According to the above configuration, the bottom wall of the inclined groove is thicker in the inner part along the radial direction of the stator core than in the outer part. That is, the strength of the bottom wall is increased in the inner part. For example, when the insulating resin expands and compresses, the load is distributed within the thick bottom wall. Also, because the bottom wall is thick, even if the crack is small, it does not reach the coil end. Therefore, insulation breakdown is suppressed.

[0015] In the above configuration, the stator may be supplied with coolant from a coolant pipe. In this case, among the plurality of grooves, the grooves arranged in an area relatively far from the coolant pipe are inclined grooves. Meanwhile, among the plurality of grooves, the grooves arranged in an area relatively close to the coolant pipe are flat grooves. The flat grooves have the same groove depth from the outer side to the inner side in the radial direction of the stator core.

[0016] According to the above-mentioned configuration, the flat groove portion is disposed in the region where the cooling efficiency is relatively high. The flat groove portion can have a thinner bottom wall than the inclined groove portion. Therefore, the amount of resin in the entire insulating ring can be reduced.

[0017] In the above configuration, the insulating ring may be formed with a reinforcing portion. In this case, the reinforcing portion is formed between the inner peripheral surface of the insulating ring and the inner end of the inclined groove portion along the radial direction of the stator core. The heights of the ridges and the reinforcing portion along the central axis of the stator core are the same. An inner ring is formed by the inner region of the ridges along the radial direction of the stator core and the reinforcing portion. The inner ring extends around the entire circumference of the insulating ring.

[0018] According to the above configuration, the inner ring is formed on the inner side of the insulating ring along the radial direction of the stator core. By providing the inner ring with the same height as the height of the protrusions, the strength of the inner side of the insulating ring is increased.

[0019] In the above configuration, a reinforcing portion may be formed between the inner peripheral surface of the insulating ring and the inner end of the inclined groove along the radial direction of the stator core. The heights of the ribs and the reinforcing portion along the central axis of the stator core are the same. An inner arc is formed by the inner region of the ribs along the radial direction of the stator core and the reinforcing portion. The inner arc extends circumferentially of the insulating ring.

[0020] The inclined grooves are disposed in a region relatively far from the coolant pipe. An inner arc is formed so as to connect the inclined grooves. By providing the inner arc with the same height as the protrusion, the strength of the inner portion of the insulating ring along the radial direction of the stator core is increased.

[0021] In the above configuration, a width of the reinforcing portion along a radial direction of the stator core may exceed a width of the coil end pair.

[0022] According to the above configuration, when the innermost coil end pair along the radial direction of the stator core generates heat, the compressive load caused by the expansion of the resin around it can be borne mainly by the reinforcing portion. Effect of the Invention

[0023] The stator according to this embodiment can suppress dielectric breakdown in the radially inner region of the insulating ring more effectively than in the past. [Brief description of the drawings]

[0024] [Figure 1] FIG. 2 is a perspective view showing a stator according to the embodiment. [Diagram 2] FIG. 13 is a perspective view showing an example in which an insulating ring is installed on a stator. [Diagram 3] FIG. 3 is a partially enlarged view of FIG. 2, illustrating the structure of a stator. [Figure 4] FIG. 11 is a perspective view showing an example in which an insulating ring according to a first modification of the present embodiment is installed on a stator. [Diagram 5] FIG. 5 is a partially enlarged view of FIG. 4, and is a perspective view for explaining the structure of a stator. [Figure 6] FIG. 11 is a perspective view showing an example in which an insulating ring according to a second modification of the embodiment is installed on a stator. [Figure 7] FIG. 11 is a perspective view showing an example in which an insulating ring according to a third modified example of the present embodiment is installed on a stator. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The stator according to the present embodiment will be described below with reference to the drawings. The shapes, materials, numbers, and values ​​described below are examples for the purpose of explanation and can be changed as appropriate according to the specifications of the stator. In the following, the same reference numerals are used for equivalent elements in all drawings.

[0026] 1 to 7 also show an axial direction A, a radial direction R, and a circumferential direction C of the stator core 20. In the following, terms such as A direction, R direction, and C direction are used as appropriate. These refer to the axial direction, radial direction, and circumferential direction of the stator core 20. [Stator configuration]

[0027] The rotating electric machine includes a stator 10 and a rotor (not shown). The stator 10 according to the present embodiment is disclosed in Fig. 1 and Fig. 2. The stator 10 includes a stator core 20, a plurality of coil segments 30, and an insulating ring 40.

[0028] The stator core 20 is a cylindrical component. A rotor (not shown) is disposed inside the cylinder. The stator core 20 is made of, for example, a hollow disk-shaped electromagnetic steel plate. The stator core is formed by stacking a plurality of electromagnetic steel plates along the axial direction (direction A). The stator core 20 includes a yoke 21 and pole teeth 22. The yoke 21 serves as a path for magnetic flux.

[0029] The pole teeth 22 extend from the inner peripheral surface of the yoke 21 toward the central axis A of the stator core 20. The pole teeth 22 are arranged circumferentially with intervals between them. In other words, the pole teeth 22 are arranged radially around the central axis A. The gaps between adjacent pole teeth 22, 22 form slots 23. Like the pole teeth 22, the slots 23 are arranged circumferentially. Note that the pole teeth 22 and slots 23 are not shown in FIG. 2.

[0030] A coil segment 30 is inserted into the slot 23. A plurality of coil segments 30 are inserted into the slot 23. The coil segment 30 is a substantially U-shaped component. That is, the coil segment 30 includes a pair of legs 31, 31 and a bent portion 32. The bent portion 32 connects the pair of legs 31, 31.

[0031] The ends of the leg portions 31 form coil ends 34. The coil segments 30 are covered with an insulating film 33, but the insulating film 33 is removed at the coil ends 34, exposing the conductor to the outside.

[0032] Each leg 31, 31 is inserted into a different slot 23. When a predetermined number of coil segments 30 have been inserted into all of the slots 23, the portion of the leg 31 protruding from the slot 23 is bent. For example, the leg 31 is bent along the circumferential direction (direction C) of the stator core 20. By bending in this manner, the axial dimension (direction A) of the stator 10 can be reduced.

[0033] 1, a pair of coil ends 34, 34 are adjacent to each other along the radial direction (R direction) of the stator core 20. The adjacent coil ends 34, 34 are welded to each other so that they are electrically connected. Hereinafter, this pair of coil ends 34, 34 will be referred to as a coil end pair 36 as appropriate.

[0034] The coil end pairs 36 are arranged in a plurality of pairs at intervals along the radial direction (direction R) of the stator core 20. A row of these coil end pairs 36 arranged in the radial direction will hereinafter be referred to as a coil end row 38 as appropriate. The coil end rows 38 are arranged in a plurality of pairs at intervals along the circumferential direction (direction C) of the stator core 20. In other words, the coil end rows 38 are arranged radially.

[0035] 2 and 3 show an insulating ring 40. The radially arranged coil end rows 38 are covered with the insulating ring 40. The insulating ring 40 is obtained by molding insulating resin into a hollow disk shape.

[0036] The insulating ring 40 includes a plurality of ridges 42 and a plurality of grooves. The insulating ring 40 illustrated in Fig. 2 and Fig. 3 includes, as the grooves, inclined grooves 44. In the example illustrated in Fig. 2 and Fig. 3, the inclined grooves 44 are provided around the entire circumference of the insulating ring 40.

[0037] With reference to Fig. 3, the protrusions 42 cover the coil end row 38. Here, the length along the circumferential direction (direction C) of the stator core 20 is defined as the width. The width W1 of the protrusions 42 is defined to exceed the width W2 of the coil end row 38. Furthermore, the dimension along the central axis direction (direction A) of the stator core 20 is defined as the height or thickness. With reference to Fig. 5, the protrusions 42 cover the coil end row 38 to a predetermined thickness T3.

[0038] 3, the width is constant among the multiple coil ends 34. Therefore, along the radial direction (R direction) of the stator core, the coil end row 38 maintains a width W2. Also, along the R direction, the protrusions 42 maintain a width W1.

[0039] A groove is disposed between adjacent coil end rows 38, 38. Since the protrusion 42 maintains a width W1 along the R direction, the groove width narrows from the outer side toward the inner side in the R direction.

[0040] 2 and 3, the insulating ring 40 has an inclined groove portion 44 disposed as a groove portion. The inclined groove portion 44 has a groove depth that becomes shallower from the outside toward the inside in the radial direction (R direction) of the stator core 20. Accordingly, a bottom wall 45 of the inclined groove portion 44 becomes thicker from the outside toward the inside in the R direction. With reference to Fig. 3, a thickness T2 of the bottom wall 45 at an inner end in the R direction is thicker than a thickness T1 of an outer end in the R direction.

[0041] That is, the strength of the bottom wall 45 of the inclined groove portion 44 is higher on the inside in the R direction than on the outside in the R direction. For example, when the coil end 34 generates heat, the resin of the insulating ring 40 expands. The compressive stress caused by the expansion is dispersed by the thick bottom wall 45. This suppresses the occurrence of cracks.

[0042] Furthermore, even if a small crack occurs, if the depth of the crack is sufficiently shallower than thickness T2, dielectric breakdown of the coil end 34 is avoided. For example, even if the depth of the crack is approximately the same as thickness T1, the end of the crack is sufficiently separated from the coil end 34 in the radially inner portion of bottom wall 45 having thickness T2. Therefore, dielectric breakdown is suppressed.

[0043] [First example of insulating ring] 4 and 5 show a first alternative embodiment of the insulating ring 40. In this embodiment, in addition to the ridges 42 and the inclined grooves 44, the insulating ring 40 is provided with an inner ring 48.

[0044] The protrusions 42 extend in the R direction and cover the coil end row 38. The inclined grooves 44 and the reinforcing portions 49 are disposed between adjacent protrusions 42. As in the case of Fig. 3, the inclined grooves 44 become shallower from the outer side toward the inner side in the radial direction (R direction) of the stator core 20. Accordingly, the bottom wall 45 of the inclined grooves 44 becomes thicker from the outer side toward the inner side in the R direction.

[0045] Here, the inclined groove portion 44 terminates just before the inner circumferential surface 40A of the insulating ring 40. That is, a reinforcing portion 49 is formed between the inner circumferential surface 40A and the inner end 44A of the inclined groove portion 44 along the R direction. The height of the reinforcing portion 49 along the C direction is the same as the height H1 of the protrusion 42.

[0046] The R-direction width L2 of the reinforcing portion 49 exceeds the width L1 of the coil end pair 36. That is, heat generated from the coil end pair 36 arranged on the innermost side along the R direction is mainly transferred to the reinforcing portion 49. That is, the compressive stress caused by thermal expansion is dispersed to the reinforcing portion 49.

[0047] The inner region of the protrusion 42 and the reinforcing portion 49 form an inner ring 48. The inner ring 48 extends around the entire inner circumference of the insulating ring 40. The thickness of the inner ring 48 is maintained at thickness H1 around the entire circumference. The inner ring 48 reinforces the inner circumferential side of the insulating ring 40. For example, compared to the insulating ring 40 illustrated in FIG. 2, the provision of the inner ring 48 further increases the strength.

[0048] When the coil end 34 generates heat, the resin of the insulating ring 40 expands. The compressive stress caused by the expansion is dispersed to the reinforcing portion 49, thereby suppressing the occurrence of cracks. Even if a small crack occurs, for example, if the depth of the crack is sufficiently shallower than the wall thickness H1, insulation breakdown of the coil end 34 is avoided.

[0049] [Second example of insulating ring] Fig. 6 shows a second example of an insulating ring 40. A protrusion 42 and a groove are formed on the insulating ring 40. The protrusion 42 has a structure similar to that of the protrusion 42 in Fig. 3. On the other hand, the groove is divided into an inclined groove portion 44 and a flat groove portion 46.

[0050] A coolant is supplied to the stator 10 through a coolant pipe 60. For example, the central axis of the stator 10 is oriented horizontally. The coolant pipe 60 is disposed above the stator 10.

[0051] The inclined groove portion 44 is disposed in an area relatively far from the coolant pipe 60. The inclined groove portion 44 has a structure similar to that of the inclined groove portion 44 in FIG. 3, for example. For example, the inclined groove portion 44 is formed in a lower portion of the insulating ring 40. That is, the inclined groove portion 44 is disposed in an area with relatively low cooling efficiency. For example, the expansion angle θ1 of the inclined groove portion 44 expanding on both sides from the vertical axis of the insulating ring 40 is 90° or more and 180° or less.

[0052] The flat groove portion 46 is disposed in a region relatively close to the coolant pipe 60. For example, the flat groove portion 46 is formed in an upper portion of the insulating ring 40. The flat groove portion 46 has a uniform groove depth from the outer side to the inner side in the R direction. For example, the bottom wall of the flat groove portion 46 is set to a thickness T1 (see FIG. 3) over the entire length.

[0053] In this manner, the flat groove portion 46 is formed in an area with relatively high cooling efficiency. By forming the flat groove portion 46 in an area with relatively low thermal fatigue, it is possible to reduce the amount of resin required to form the insulating ring 40. The expansion angle θ2 of the flat groove portion 46 is equal to or greater than 180° and equal to or less than 270°.

[0054] [Third example of insulating ring] 7 shows a third example of the insulating ring 40. The insulating ring 40 is formed with a protrusion 42 and a groove. The groove is divided into an inclined groove 44 and a flat groove 46. The protrusion 42 has a structure similar to that of the protrusion 42 in FIG. 3. The flat groove 46 has a structure similar to that of the flat groove 46 in FIG. 6. The insulating ring 40 also includes an inner arc 50, which will be described later.

[0055] A coolant is supplied to the stator 10 through a coolant pipe 60. For example, the central axis of the stator 10 is oriented horizontally. The coolant pipe 60 is disposed above the stator 10.

[0056] The flat groove portion 46 is disposed in a region relatively close to the coolant pipe 60. For example, the flat groove portion 46 is formed in an upper portion of the insulating ring 40. The expansion angle θ4 of the flat groove portion 46 is equal to or greater than 180° and equal to or less than 270°.

[0057] The inclined groove portion 44 is disposed in a region relatively far from the coolant pipe 60. For example, the inclined groove portion 44 is formed in a lower portion of the insulating ring 40. The expansion angle θ3 of the inclined groove portion 44 is equal to or greater than 90° and equal to or less than 180°. The inclined groove portion 44 has the same structure as the inclined groove portion 44 in FIG. 5.

[0058] A reinforcing portion 49 is formed between the inner peripheral surface 40A of the insulating ring 40 and the inner end 44A of the inclined groove portion 44. The structure of the reinforcing portion 49 is similar to that of the reinforcing portion 49 in FIG.

[0059] The inner region of the protrusion 42 and the reinforcing portion 49 form an inner arc 50 which is an arc portion. The inner arc 50 extends in the circumferential direction of the insulating ring 40. For example, the inner arc 50 extends over a spreading angle θ3 of the inclined groove portion 44. The spreading angle θ3 is, for example, not less than 90° and not more than 180°. In a region relatively far from the coolant pipe 60, the inner peripheral side of the insulating ring 40 is reinforced by the inner arc 50. [Explanation of symbols]

[0060] 10 stator, 20 stator core, 30 coil segment, 34 coil end, 36 coil end pair, 38 coil end row, 40 insulating ring, 40A inner circumferential surface, 42 ridge, 44 inclined groove portion, 45 bottom wall, 46 flat groove portion, 48 inner ring, 49 reinforcing portion, 50 inner arc, 60 coolant pipe.

Claims

1. A stator core having a cylindrical shape and a plurality of slots arranged circumferentially on a radially inner side thereof; A plurality of coil segments inserted into the plurality of slots; an insulating ring covering a coil end which is an end of each of the coil segments; A stator comprising: A plurality of coil end pairs, each of which is connected to a pair of coil ends, are arranged along a radial direction of the stator core, The coil end pairs are arranged radially at intervals along the circumferential direction of the stator core, A plurality of radially arranged rows of the coil end pairs are covered by the insulating ring, the insulating ring includes a plurality of protrusions covering the rows of coil end pairs and a plurality of grooves disposed between adjacent rows of the coil end pairs; At least some of the grooves are inclined grooves having a groove depth that becomes shallower from the outer side toward the inner side in the radial direction of the stator core, A bottom wall of the inclined groove portion becomes thicker from the outer side toward the inner side in the radial direction of the stator core. Stator.

2. 2. The stator according to claim 1, Coolant is supplied from the coolant pipe, Among the plurality of grooves, the grooves arranged in an area relatively far from the coolant pipe are the inclined grooves, Among the plurality of grooves, the grooves arranged in a region relatively close to the coolant pipe are flat grooves having a uniform groove depth from the outer side to the inner side in the radial direction of the stator core. Stator.

3. 2. The stator according to claim 1, a reinforcing portion is formed between an inner circumferential surface of the insulating ring and an inner end of the inclined groove portion along a radial direction of the stator core, The height of the protrusion and the reinforcing portion along the central axis of the stator core are the same, an inner ring is formed by an inner region of the protrusion along a radial direction of the stator core and the reinforcing portion, the inner ring extending around the entire circumference of the insulating ring; Stator.

4. 3. The stator according to claim 2, a reinforcing portion is formed between an inner circumferential surface of the insulating ring and an inner end of the inclined groove portion along a radial direction of the stator core, The height of the protrusion and the reinforcing portion along the central axis of the stator core are the same, an inner arc is formed by an inner region of the protrusion along a radial direction of the stator core and the reinforcing portion, the inner arc extending in a circumferential direction of the insulating ring; Stator.

5. 5. A stator according to claim 3 or 4, A width of the reinforcing portion along a radial direction of the stator core exceeds a width of the coil end pair. Stator.

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