stata

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 of a rotating electric machine. In particular, this specification relates to the shape of an insulating ring that covers the coil ends of the stator.

Background Art

[0002] A rotating electric machine includes a stator. The stator includes a stator core and coils. The stator core is a cylindrical component. Slots are 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 winding a single coil around the stator core from a starting point to an ending point, a plurality of coil segments may be used. A coil segment is a wiring component having a substantially U-shaped form. By welding the coil ends of one coil segment to those of the other coil segment, the pair of coil segments are electrically connected.

[0004] The surface of the coil segment is coated with an 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 for all pairs of coil ends in the stator core is completed, the coil ends are covered with an insulating ring. The insulating ring is disclosed in, for example, Patent Documents 1 and 2.

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

[0006] To avoid unintentional electrical connection, a pair of coil ends are separated from the surrounding coil ends. For example, a plurality of 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 an uneven surface. This insulating ring has protrusions where it covers the coil ends. Furthermore, the insulating ring has grooves in the gaps between the coil ends, and the protrusions and grooves extend along the radial direction of the stator core. The protrusions and grooves are also arranged radially. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2017-189058 [Patent Document 2] Japanese Patent Publication No. 2022-174650 [Overview of the project] [Problems that the invention aims to solve]

[0009] Incidentally, as the ridges are arranged radially, the grooves located between adjacent ridges become narrower in width as they move towards the radial center of the stator core.

[0010] During operation of the rotating electric machine, the coils generate heat. Consequently, the insulating ring becomes hot. At this time, the resin of the insulating ring expands. As a result, compressive stress is generated in the grooves. When the rotating electric machine is idle, the resin between the coils contracts as the temperature of the insulating ring decreases. Consequently, tensile stress is generated in the grooves.

[0011] Thus, the grooves are subjected 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 compared to the radially outer region. This means that load distribution becomes difficult during expansion and compression. Therefore, cracks due to thermal fatigue may occur in the radially inner region of the grooves. And if the cracks reach the coil end, for example, dielectric 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 effectively than conventional stators. [Means for solving the problem]

[0013] The stator disclosed in this embodiment comprises a stator core, a plurality of coil segments, and an insulating ring. The stator core is a cylindrical component. A plurality of slots are arranged radially inward 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. A coil end is the end of a coil segment. A pair of coil ends are connected to each other to form a coil end pair. Multiple pairs of coil end pairs are arranged radially along the stator core. Multiple rows of coil end pairs are arranged radially at intervals along the circumferential direction of the stator core. Multiple radially arranged rows of coil end pairs are covered by the insulating ring. The insulating ring comprises a plurality of protrusions and a plurality of grooves. The protrusions cover the rows of coil end pairs. The grooves are located between adjacent rows of coil end pairs. At least some of the multiple grooves are inclined grooves. In the inclined groove section, the groove depth decreases from the radially outer side to the inner side of the stator core. Here, the bottom wall of the inclined groove section also increases from the radially outer side to the inner side of the stator core.

[0014] According to the above configuration, the bottom wall of the inclined groove is thicker in the inner portion along the radial direction of the stator core compared to the outer portion. In other words, the strength of the bottom wall is increased in the inner portion. For example, when the insulating resin expands and compresses, the load is distributed within the thicker bottom wall. Also, because the bottom wall is thick, small cracks will not reach the coil end. Therefore, dielectric breakdown is suppressed.

[0015] In the above configuration, the stator may be supplied with coolant from a coolant pipe. In this case, among the multiple grooves, the grooves located in the region relatively far from the coolant pipe are inclined grooves. On the other hand, among the multiple grooves, the grooves located in the region relatively close to the coolant pipe are flat grooves. In the flat grooves, the groove depth is the same from the radially outer side to the inner side of the stator core.

[0016] According to the above configuration, flat grooves are placed in regions with relatively high cooling efficiency. Compared to inclined grooves, the bottom walls of the flat grooves can be made thinner. Therefore, the total amount of resin used in the insulating ring can be reduced.

[0017] Furthermore, in the above configuration, a reinforcing portion may be formed on the insulating ring. In this case, the reinforcing portion is formed between the inner circumferential surface of the insulating ring and the inner end of the inclined groove portion along the radial direction of the stator core. The height of the projection 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 projection 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, an inner ring is formed on the inner portion of the insulating ring, along the radial direction of the stator core. By providing an inner ring with the same height as the ridge, the strength of the inner portion of the insulating ring is increased.

[0019] Furthermore, in the above configuration, a reinforcing portion may be formed between the inner circumferential surface of the insulating ring and the inner end of the inclined groove portion along the 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 the inner region of the protrusion along the radial direction of the stator core and the reinforcing portion. The inner arc extends along the circumferential direction of the insulating ring.

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

[0021] Also, in the above configuration, the width of the reinforcing portion along the radial direction of the stator core may exceed the 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 reinforcing portion can mainly receive the compressive load due to the expansion of the surrounding resin.

Effect of the Invention

[0023] The stator according to the present embodiment can suppress dielectric breakdown in the radially inner region of the insulating ring more effectively than before.

Brief Description of the Drawings

[0024] [Figure 1] It is a perspective view showing a stator according to the present embodiment. [Figure 2] It is a perspective view showing an example in which an insulating ring is installed on the stator. [Figure 3] It is a partially enlarged view of FIG. 2 and is a perspective view for explaining the structure of the stator. [Figure 4] It is a perspective view showing an example in which an insulating ring according to a first alternative example of the present embodiment is installed on the stator. [Figure 5] It is a partially enlarged view of FIG. 4 and is a perspective view for explaining the structure of the stator. [Figure 6] It is a perspective view showing an example in which an insulating ring according to a second alternative example of the present embodiment is installed on the stator. [Figure 7] It is a perspective view showing an example in which an insulating ring according to a third alternative example of the present embodiment is installed on the stator.

Mode for Carrying Out the Invention

[0025] The stator according to this embodiment will be described below with reference to the drawings. The shapes, materials, quantities, and numerical values ​​described below are illustrative examples for illustrative purposes and can be appropriately changed according to the specifications of the stator. In addition, in all drawings below, equivalent elements will be denoted by the same reference numerals.

[0026] Figures 1-7 show the axial direction A, radial direction R, and circumferential direction C of the stator core 20. Hereafter, terms such as direction A, direction R, and direction C will be used as appropriate. These refer to the axial, radial, and circumferential directions of the stator core 20. [Stator configuration]

[0027] The rotating electric machine comprises a stator 10 and a rotor (not shown). Figures 1 and 2 disclose a stator 10 according to this embodiment. The stator 10 comprises 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 placed inside the cylinder. The stator core 20 is made of, for example, a hollow disc-shaped electromagnetic steel sheet. Multiple electromagnetic steel sheets are stacked along the axial direction (direction A) to form the stator core. The stator core 20 includes a yoke 21 and pole teeth 22. The yoke 21 serves as a passage for magnetic flux.

[0029] The pole teeth 22 extend from the inner circumferential surface of the yoke iron 21 toward the central axis A of the stator core 20. The pole teeth 22 are spaced apart in the circumferential direction and arranged in a circular pattern. 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. Similar to the pole teeth 22, the slots 23 are arranged in a circular pattern. Note that the pole teeth 22 and slots 23 are not shown in Figure 2.

[0030] A coil segment 30 is inserted into slot 23. Multiple coil segments 30 are inserted into slot 23. The coil segment 30 is a roughly U-shaped component. That is, the coil segment 30 comprises 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 are coil ends 34. The coil segments 30 are covered with an insulating film 33, but the insulating film 33 is peeled off at the coil ends 34, exposing the conductor to the outside.

[0032] Each leg portion 31, 31 is inserted into a different slot 23. Once a predetermined number of coil segments 30 have been inserted into all slots 23, the portion of the leg portion 31 that protrudes from the slot 23 is bent. For example, the leg portion 31 is bent along the circumferential direction (C direction) of the stator core 20. This bending reduces the axial dimension (A direction) of the stator 10.

[0033] As illustrated in Figure 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 together, creating electrical contact between them. This pair of coil ends 34, 34 will be referred to as a coil end pair 36 hereafter.

[0034] Multiple pairs of coil end pairs 36 are arranged at intervals along the radial direction (R direction) of the stator core 20. These radial rows of coil end pairs 36 will be referred to as coil end rows 38 below. Multiple coil end rows 38 are arranged at intervals along the circumferential direction (C direction) of the stator core 20. That is, the coil end rows 38 are arranged radially.

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

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

[0037] Referring to Figure 3, the protrusion 42 covers 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 protrusion 42 is defined to exceed the width W2 of the coil end row 38. Also, the dimension along the central axis direction (direction A) of the stator core 20 is defined as the height or thickness. Referring to Figure 5, the protrusion 42 covers the coil end row 38 with a predetermined thickness T3.

[0038] Referring to Figure 3, the width is constant between the multiple coil ends 34. Therefore, along the radial direction (R direction) of the stator core, the coil end row 38 is maintained at a width W2. Also, the protrusions 42 are maintained at a width W1 along the R direction.

[0039] A groove is positioned between adjacent coil end rows 38, 38. As the protrusion 42 is maintained at a width W1 along the R direction, the groove width narrows from the outside to the inside in the R direction.

[0040] As illustrated in Figures 2 and 3, the insulating ring 40 has inclined grooves 44. The inclined grooves 44 become shallower from the outside to the inside 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 outside to the inside in the R direction. Referring to Figure 3, the thickness T2 of the bottom wall 45 at the inner end in the R direction is thicker than the thickness T1 at the outer end in the R direction.

[0041] In other words, the bottom wall 45 of the inclined groove 44 has higher strength 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 associated with the expansion is distributed to the thick bottom wall 45. This suppresses the occurrence of cracks.

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

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

[0044] The protrusions 42 extend in the R direction and cover the coil end row 38. Inclined grooves 44 and reinforcing sections 49 are positioned between adjacent protrusions 42. Similar to Figure 3, the groove depth of the inclined grooves 44 decreases from the radially (R direction) outside to the inside of the stator core 20. Consequently, the bottom wall 45 of the inclined grooves 44 thickens from the radially (R direction) outside to the inside.

[0045] Here, the inclined groove 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 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 reinforcement section 49 exceeds the width L1 of the coil end pair 36. In other words, the heat generated from the innermost coil end pair 36 along the R-direction is mainly transferred to the reinforcement section 49. That is, the compressive stress associated with thermal expansion is distributed to the reinforcement section 49.

[0047] An inner ring 48 is formed by the inner region of the protrusion 42 and the reinforcing portion 49. The inner ring 48 extends along the entire circumference of the insulating ring 40. The thickness of the inner ring 48 is maintained at a thickness H1 throughout its entire circumference. The inner ring 48 reinforces the inner circumference of the insulating ring 40. For example, compared to the insulating ring 40 illustrated in Figure 2, the strength is further increased by providing the inner ring 48.

[0048] When the coil end 34 generates heat, the resin of the insulating ring 40 expands. The compressive stress associated with this expansion is distributed to the reinforcing portion 49. This suppresses the occurrence of cracks. Furthermore, even if small cracks occur, for example, if the depth of the cracks is sufficiently shallower than the wall thickness H1, dielectric breakdown of the coil end 34 is avoided.

[0049] [Another example of an insulating ring] Figure 6 shows a second alternative example of the insulating ring 40. The insulating ring 40 has protrusions 42 and grooves formed therein. The protrusions 42 have the same structure as the protrusions 42 in Figure 3. On the other hand, the grooves are divided into inclined grooves 44 and flat grooves 46.

[0050] Coolant is supplied to the stator 10 from the coolant pipe 60. For example, the stator 10 is oriented with its central axis horizontally. The coolant pipe 60 is positioned above the stator 10.

[0051] The inclined groove 44 is positioned in a region relatively far from the coolant pipe 60. The inclined groove 44 has a structure similar to the inclined groove 44 in Figure 3, for example. For example, the inclined groove 44 is formed in the lower part of the insulating ring 40. In other words, the inclined groove 44 is positioned in a region with relatively low cooling efficiency. For example, the development angle θ1 of the inclined groove 44 extending from the vertical axis of the insulating ring 40 on both sides is between 90° and 180°.

[0052] The flat groove 46 is positioned in a region relatively close to the coolant pipe 60. For example, the flat groove 46 is formed in the upper portion of the insulating ring 40. The groove depth of the flat groove 46 is the same from the outside to the inside in the R direction. For example, the bottom wall of the flat groove 46 has a wall thickness T1 (see Figure 3) along its entire length.

[0053] In this way, the flat grooves 46 are formed in regions with relatively high cooling efficiency. By making the regions with relatively low thermal fatigue the flat grooves 46, the amount of resin required to form the insulating ring 40 can be reduced. The development angle θ2 of the flat grooves 46 is between 180° and 270°.

[0054] [Third alternative example of an insulating ring] Figure 7 shows a third alternative example of the insulating ring 40. The insulating ring 40 has protrusions 42 and grooves. The grooves are divided into inclined grooves 44 and flat grooves 46. The protrusions 42 have the same structure as the protrusions 42 in Figure 3. The flat grooves 46 have the same structure as the flat grooves 46 in Figure 6. The insulating ring 40 also includes an inner arc 50, which will be described later.

[0055] Coolant is supplied to the stator 10 from the coolant pipe 60. For example, the stator 10 is oriented with its central axis horizontally. The coolant pipe 60 is positioned above the stator 10.

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

[0057] The inclined groove 44 is positioned in a region relatively far from the coolant pipe 60. For example, the inclined groove 44 is formed in the lower part of the insulating ring 40. The expansion angle θ3 of the inclined groove 44 is between 90° and 180°. The inclined groove 44 has the same structure as the inclined groove 44 in Figure 5.

[0058] A reinforcing portion 49 is formed between the inner circumferential 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 the same as that of the reinforcing portion 49 in Figure 5.

[0059] The inner region of the protrusion 42 and the reinforcing portion 49 form an inner arc 50, which is an arc-shaped portion. The inner arc 50 extends along the circumferential direction of the insulating ring 40. For example, the inner arc 50 extends along the development angle θ3 of the inclined groove portion 44. The development angle θ3 is, for example, between 90° and 180°. In the region relatively far from the coolant pipe 60, the inner circumference 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 surface, 42 Rivet, 44 Inclined groove, 45 Bottom wall, 46 Flat groove, 48 Inner ring, 49 Reinforcement, 50 Inner arc, 60 Coolant pipe.

Claims

1. A stator core having a cylindrical shape, with multiple slots arranged circumferentially on its radially inner side, Multiple coil segments are inserted into multiple slots, An insulating ring covers the coil end, which is the end of each of the aforementioned coil segments, A stator equipped with, Multiple pairs of coil end pairs, each consisting of two coil ends connected to one another, are arranged along the radial direction of the stator core. The rows of the coil end pairs are arranged radially at intervals along the circumferential direction of the stator core, The rows of the coil end pairs arranged radially are covered by the insulating ring, The insulating ring comprises a plurality of protrusions covering the row of coil end pairs and a plurality of grooves positioned between adjacent rows of coil end pairs. At least a portion of the plurality of grooves are inclined grooves in which the groove depth decreases from the radially outer side to the inner side of the stator core. The bottom wall of the inclined groove thickens from the radially outer side to the inner side of the stator core. Coolant is supplied from the coolant pipe. Of the multiple grooves, the groove located in a region relatively far from the coolant pipe is the inclined groove. Of the multiple grooves, the grooves located in a region relatively close to the coolant pipe are flat grooves in which the groove depth is the same from the radially outer side to the inner side of the stator core. stata.

2. A stator core having a cylindrical shape, wherein a plurality of slots are arranged circumferentially on the radially inner side, Multiple coil segments are inserted into multiple slots, An insulating ring covers the coil end, which is the end of each of the aforementioned coil segments, A stator equipped with, Multiple pairs of coil end pairs, each consisting of two coil ends connected to one another, are arranged along the radial direction of the stator core. The rows of the coil end pairs are arranged radially at intervals along the circumferential direction of the stator core, The rows of the coil end pairs arranged radially are covered by the insulating ring, The insulating ring comprises a plurality of protrusions covering the row of coil end pairs and a plurality of grooves positioned between adjacent rows of coil end pairs. At least a portion of the plurality of grooves are inclined grooves in which the groove depth decreases from the radially outer side to the inner side of the stator core. The bottom wall of the inclined groove thickens from the radially outer side to the inner side of the stator core. A reinforcing portion is formed between the inner circumferential surface of the insulating ring and the inner end of the inclined groove portion along the 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 the inner region of the protrusion along the radial direction of the stator core and the reinforcing portion, extending over the entire circumference of the insulating ring. stata.

3. A stator according to claim 1, A reinforcing portion is formed between the inner circumferential surface of the insulating ring and the inner end of the inclined groove portion along the 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 the inner region of the protrusion along the radial direction of the stator core and the reinforcing portion, extending circumferentially across the insulating ring. stata.

4. A stator according to claim 2 or 3, The width of the reinforcing portion along the radial direction of the stator core exceeds the width of the coil end pair. stata.

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