Cooling system, stator of rotary electric machine, and segmented coil

Abstract

The present application relates to a cooling system, a stator of a rotary electric machine, and a segmented coil. A coil end projects outward from a first end of a stator core in a direction along a central axis. An imaginary straight line is orthogonal to both the central axis of the core body and an axis extending in the up-down direction. A first portion is an upper portion among the coil end divided by the imaginary straight line. The portion constituting the first portion among the segmented coil has an outer peripheral surface facing in a direction opposite to the central axis. The outer peripheral surface of the segmented coil has a twisted surface, and the closer the twisted surface is to the first end of the stator core, the closer the direction faced by the twisted surface is to the direction facing the stator core.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a cooling system, a stator of a rotary electric machine, and a segment coil. BACKGROUND

[0002] A cooling system described in Japanese Patent Application Publication No. 2006-311750 is equipped with a rotary electric machine and a cooling oil passage through which oil flows. The rotary electric machine is equipped with a stator that is circular ring-shaped and a rotor that is located in a radial direction inner side from the stator. The stator has a stator core and a plurality of segment coils. The stator core is circular ring-shaped. Each of the segment coils is wound around the stator.

[0003] Each of the segment coils is equipped with a portion that protrudes from an end surface of the stator, i.e., so-called coil end portion, in a direction along a center axis of the stator. The cooling oil passage is equipped with a jet hole. The cooling oil passage is located above from the stator core.

[0004] When oil is jetted from the cooling oil passage toward the coil end portion of the rotary electric machine, the oil flows downward as it is after the oil contacts the coil end portion due to gravity. Thus, there is a case where the oil does not spread over the entire coil end portion, and a desired cooling effect cannot be obtained. SUMMARY

[0005] A cooling system according to an aspect of the present disclosure is equipped with a rotary electric machine mounted on a vehicle and a cooling oil passage through which oil flows. The rotary electric machine is equipped with a stator core and a plurality of segment coils mounted to the stator core. The stator core is equipped with a core body that is circular ring-shaped and has a center axis extending in a direction orthogonal to an axis extending upward and downward of the vehicle, and a plurality of teeth extending from an inner peripheral surface of the core body toward the center axis. Each of the segment coils is inserted between the teeth. Each of the segment coils is equipped with a coil end portion that protrudes outward from a first end of the stator core in a direction along the center axis. The cooling oil passage is equipped with a jet hole for jetting oil toward the coil end portion. The jet hole is located above from the coil end portion. A straight line that is orthogonal to both the center axis and the axis extending upward and downward when viewed in the direction along the center axis is referred to as an imaginary straight line. An upper portion of the coil end portion that is bisected by the imaginary straight line is referred to as a first portion. A portion of the segment coils that constitutes the first portion has an outer peripheral surface that faces toward a direction opposite to the center axis from the portion of the segment coils that constitutes the first portion. The outer peripheral surface of the segment coil has a twist surface. The twist surface is configured such that the closer to the first end of the stator core, the closer to a direction facing the stator core the twist surface faces.

[0006] In the above structure, the oil ejected from the ejection hole hits the outer peripheral surface among the segment coils of the first portion. The oil hitting the outer peripheral surface of the segment coil drips from the segment coil to the outside of the stator, or flows along the outer peripheral surface of the segment coil. According to the above structure, the oil hitting the outer peripheral surface of the segment coil is easily guided in the direction of the first end of the stator core along the torsion surface among the outer peripheral surface. Thus, the amount of oil dripping to the outside of the stator is reduced. Since the oil guided in the direction of the first end of the stator falls along the plurality of segment coils, the coil end portion is effectively cooled.

[0007] In the above structure, the lower portion among the coil end portions bisected by the imaginary straight line is referred to as a second portion. The portion among the segment coils constituting the second portion has an inner peripheral surface facing in the direction toward the center axis from the portion among the segment coils constituting the second portion. The outer peripheral surface of the segment coil has a first torsion surface. The inner peripheral surface of the segment coil has a second torsion surface. The second torsion surface can also be configured such that the closer to the first end of the stator core, the closer to the direction facing the stator core the second torsion surface faces.

[0008] In the above structure, the oil falling from the segment coil of the first portion hits the inner peripheral surface among the segment coils of the second portion. The oil hitting the inner peripheral surface of the segment coil drips from the segment coil to the outside of the stator, or flows along the inner peripheral surface of the segment coil. The oil hitting the inner peripheral surface of the segment coil is easily guided in the direction of the first end of the stator core along the second torsion surface among the inner peripheral surface of the segment coil. Thus, the amount of oil dripping to the outside of the stator is reduced. The oil guided in the direction of the first end of the stator falls along the plurality of segment coils. Thus, the coil end portion is effectively cooled.

[0009] In the above structure, the segment coil can also be equipped with a plurality of dimples of a recess that is circular in plan view on the surface of the segment coil. According to the above structure, the oil flowing along the segment coil smoothly flows on the surface of the segment coil. Thus, the oil is less likely to drip from the segment coil to the outside of the stator.

[0010] Further, a stator of a rotating electric machine according to another aspect of the present disclosure is provided with a stator core, and a plurality of segment coils mounted to the stator core. The stator core is provided with a ring-shaped core body having a center axis, and a plurality of teeth extending from an inner peripheral surface of the core body toward the center axis. Each of the segment coils is inserted between the teeth. Each of the segment coils is provided with a coil end portion that protrudes outward from a first end of the stator core in a direction along the center axis. A straight line that is orthogonal to the center axis when viewed in the direction along the center axis is referred to as an imaginary straight line. One of the coil end portions that is bisected by the imaginary straight line is referred to as a first portion. The portion of the segment coil that constitutes the first portion has an outer peripheral surface that faces toward a direction opposite to the center axis from the portion of the segment coil that constitutes the first portion. The outer peripheral surface of the segment coil has a twist surface. The twist surface is configured such that the closer to the first end of the stator core, the closer to a direction facing the stator core the direction in which the twist surface faces.

[0011] The stator of the above structure is configured such that the center axis is parallel to a horizontal plane and the first portion is upward. Oil is supplied from above the stator. The oil hits the outer peripheral surface of the segment coil in the first portion. The oil that hits the outer peripheral surface of the segment coil drips from the segment coil to outside the stator, or flows along the outer peripheral surface of the segment coil. According to the above structure, the oil that hits the outer peripheral surface of the segment coil is easily guided in the direction toward the first end of the stator core along the twist surface in the outer peripheral surface. Thus, the amount of oil that drips to outside the stator is reduced. The oil that is guided in the direction toward the first end of the stator core falls along the plurality of segment coils. Thus, the coil end portions are effectively cooled.

[0012] In the above structure, the other of the coil end portions that is bisected by the imaginary straight line is referred to as a second portion. The portion of the segment coil that constitutes the second portion has an inner peripheral surface that faces toward a direction opposite to the center axis from the portion of the segment coil that constitutes the second portion. The twist surface of the outer peripheral surface of the segment coil is a first twist surface. The inner peripheral surface of the segment coil has a second twist surface. The second twist surface can also be configured such that the closer to the first end of the stator core, the closer to a direction facing the stator core the direction in which the second twist surface faces.

[0013] According to the above structure, in a case where the stator is configured such that the first portion is upper and the second portion is lower, oil falling from the segment coil of the first portion hits the inner peripheral surface among the segment coils of the second portion. The oil hitting the inner peripheral surface of the segment coil drips from the segment coil to the outside of the stator, or flows along the inner peripheral surface of the segment coil. The oil hitting the inner peripheral surface of the segment coil is easily guided in a direction along the second torsion surface among the inner peripheral surface toward the first end of the stator core. Thus, the amount of oil dripping to the outside of the stator is reduced. Since the oil guided in the direction toward the first end of the stator falls along the plurality of segment coils, the coil end portions are effectively cooled.

[0014] Further, a segment coil provided by still another aspect of the present disclosure is mounted to a stator core. The segment coil is equipped with a pair of straight portions extending in parallel to each other in a straight line shape and a pair of curved portions each connecting end portions of the same direction among the pair of straight portions to each other. An axis orthogonal to a plane including both of the pair of straight portions is referred to as an orthogonal axis. The curved portion has a side surface facing in either of two directions along the orthogonal axis as viewed from the curved portion. The side surface has a torsion surface. The torsion surface is configured such that the closer to an intersection of the straight portion and the curved portion, the closer to a direction facing the straight portion the direction facing of the torsion surface.

[0015] The segment coil of the above structure is mounted to a stator core having a central axis. The stator core is configured such that the central axis is parallel to a horizontal plane and a torsion surface is upper. Oil is supplied from above the stator core. The oil hits the torsion surface among the segment coils. According to the above structure, the oil hitting the torsion surface of the segment coil is easily guided along the torsion surface toward the intersection of the straight portion and the curved portion. That is, the oil is easily diffused along the torsion surface throughout the segment coil. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a schematic end view of a cooling system.

[0017] Figure 2 is a schematic view of a 2-2 cross section of Figure 1

[0018] Figure 3 is a partial enlarged view of a coil end portion of the first portion shown in Figure 1

[0019] Figure 4 is a partial enlarged view of a coil end portion of the second portion shown in Figure 1

[0020] Figure 5 is a schematic view showing Figure 3 Figure 4 ​​​​A schematic view of a recess of a segment coil. DETAILED DESCRIPTION

[0021] In this specification, "at least one of A and B" is understood to mean "only A", or "only B", or "both A and B".

[0022] <Outline of Configuration>

[0023] Hereinafter, with reference to Figures 1 to 5 An embodiment of a cooling system will be described.

[0024] As Figure 1 shown, a cooling system 100 is equipped with a motor generator 10 and a cooling oil passage 50.

[0025] The motor generator 10 is equipped with a stator 20 and a rotor 40. The motor generator 10 is an example of a rotary electric machine. The motor generator 10 is mounted on a vehicle. In addition, a drawing of the vehicle is omitted.

[0026] The stator 20 is circular as a whole. The stator 20 is equipped with a stator core 30, and a plurality of segment coils 21 mounted to the stator core 30. The stator core 30 is circular as a whole. Thus, the stator core 30 has a center axis CA. The motor generator 10 is mounted on the vehicle in such a manner that the center axis CA of the stator core 30 is orthogonal to an axis (second axis Y) extending in the up-down direction of the vehicle. The stator core 30 is formed by laminating a plurality of electromagnetic steel sheets that are magnetic bodies.

[0027] The segment coil 21 is equipped with a coil end portion 22 that protrudes outward from a first end 30a of the stator core 30 in the direction along the center axis CA. The first end 30a can be either of the left end and the right end of the stator core 30 as shown, but for the sake of convenience, here, the left end of the stator core 30 is assumed. In addition, the segment coil 21 is equipped with a coil end portion 22 that protrudes outward from a second end 30b of the stator core 30 in the direction opposite to the first end 30a in the direction along the center axis CA. That is, the segment coil 21 is equipped with the coil end portion 22 as a portion that protrudes from both end surfaces of the first end 30a and the second end 30b of the stator core 30, respectively. In addition, in Figure 1 the plurality of segment coils 21 are collectively shown as a cylindrical shape. Figure 1 Figure 1

[0028] ​​The rotor 40 is cylindrical as a whole. Viewed from the stator 20, the rotor 40 is located radially inward. The rotor 40 is equipped with a rotor shaft 41 and a rotor core 42. The rotor shaft 41 is rod-shaped. The central axis of the rotor shaft 41 coincides with the central axis CA of the stator core 30. The end of the rotor shaft 41 is connected to a housing surrounding the electric generator 10. The housing is omitted from the illustration. The rotor core 42 is annular. The inner circumferential surface of the rotor core 42 is fixed to the outer circumferential surface of the rotor shaft 41. The rotor core 42 is formed by stacking multiple electromagnetic steel plates, which are magnetic bodies. Although omitted from the illustration, the rotor core 42 contains multiple magnets. These magnets are embedded in grooves formed in the electromagnetic steel plates of the rotor core 42.

[0029] In the following description, the axis extending along the central axis CA will be designated as the first axis X. The axis orthogonal to the central axis CA will be designated as the second axis Y. One direction along the first axis X will be designated as the first positive direction X1, and the other direction along the first axis X will be designated as the first negative direction X2. Similarly, one direction along the second axis Y will be designated as the second positive direction Y1, and the other direction along the second axis Y will be designated as the second negative direction Y2. Furthermore, the second negative direction Y2 is aligned with the direction of gravity. That is, the second axis Y is the same as the axis extending vertically along the vehicle.

[0030] like Figure 1 As shown, the cooling oil passage 50, viewed from the electric generator 10, is located in the second positive direction Y1. The cooling oil passage 50 is a pipe or the like for supplying oil flow. The cooling oil passage 50 has multiple injection holes 51. These injection holes 51 are for injecting oil into the coil end 22. Viewed from the coil end 22, the multiple injection holes 51 are located on the side of the second positive direction Y1. The multiple injection holes 51 face the second negative direction Y2. One of the multiple injection holes 51, viewed from the stator 20, is located directly above the coil end 22 in the first positive direction X1. Another of the multiple injection holes 51 is located directly above the coil end 22 in the first negative direction X2. Oil within the cooling oil passage 50 is injected into the coil end 22 towards the second negative direction Y2 through the injection holes 51.

[0031] <About stator>

[0032] like Figure 2 As shown, the stator core 30 is equipped with a core body 31 and a plurality of teeth 32. The core body 31 is annular. The central axis of the core body 31 coincides with the central axis CA of the stator core 30. Each tooth 32 extends from the inner circumference of the core body 31 towards the central axis CA. The teeth 32 are evenly spaced in the circumferential direction of the core body 31, thus creating gaps between adjacent teeth 32. Segmented coils 21 are inserted between adjacent teeth 32.

[0033] As Figure 3 and Figure 4 shown, each segment coil 21 becomes a loop as a whole. In addition, each segment coil 21 is formed by welding end portions of a plurality of wires to each other. In Figure 3 and Figure 4 , a portion of the loop of the segment coil 21 is shown. The segment coil 21 has a quadrangular shape in cross section. The segment coil 21 has a pair of straight portions 201 extending in straight lines. The straight portions 201 extend in parallel to each other. In addition, the segment coil 21 is provided with a pair of curved portions 202 connecting end portions in the same direction in the pair of straight portions 201 to each other. Each straight portion 201 is located between adjacent teeth 32 to each other. In addition, one straight portion 201 in the pair of straight portions 201 is located between different teeth 32 to each other from the teeth 32 where the other straight portion 201 is located. Each curved portion 202 constitutes a coil end portion 22.

[0034] Here, as shown in Figure 2 , an imaginary straight line VL orthogonal to both the center axis CA and the second axis Y2 when the stator 20 is viewed in the second positive direction X2 is drawn. A portion of the coil end portion 22 divided into two vertically by the imaginary straight line VL when the stator 20 is viewed in the second positive direction X2 and which is in the direction of the second positive direction Y1, that is, the upper side, from the imaginary straight line VL is called a first portion 22A. In addition, a portion of the coil end portion 22 divided into two vertically by the imaginary straight line VL when the stator 20 is viewed in the second positive direction X2 and which is in the direction of the second negative direction Y2, that is, the lower side, from the imaginary straight line VL is called a second portion 22B.

[0035] <About Coil End Portion>

[0036] As Figure 3As shown, each of the curved portions 202 of the coil end 22 of the first portion 22A has four sides around the wire of the coil. An outer peripheral surface Pl that is one of the four sides faces a direction opposite to the center axis CA. Here, an axis orthogonal to a plane that contains both of the pair of straight portions 201 of the segmented coil 21 is referred to as an orthogonal axis PL. At this time, the outer peripheral surface Pl is a side that, as viewed from the curved portion 202, faces one of two directions along the orthogonal axis PL. Further, below, sometimes the direction opposite to the center axis CA among the two directions along the orthogonal axis PL is referred to as the outer direction, and the direction toward the center axis CA is referred to as the inner direction. In the coil end 22 of the first portion 22A, the outer peripheral surface Pl has a first torsion surface as a torsion surface. The first torsion surface is configured such that the closer to the end of the stator core 30, i.e., the first end 30a, the closer to the direction facing the stator core 30 the direction faced by the first torsion surface. That is, the closer to the intersection of the straight portion 201 and the curved portion 202 the first torsion surface, the closer to the direction facing the straight portion 201 the direction faced by the first torsion surface. In the example shown, the closer the outer peripheral surface Pl faces the lower direction, i.e., the first negative direction X2, the closer to the lower direction, i.e., the first negative direction X2 the direction faced by the outer peripheral surface Pl. In the present embodiment, the entire outer peripheral surface Pl is the first torsion surface. Figure 3 In the example shown, the closer the outer peripheral surface Pl faces the lower direction, i.e., the first negative direction X2, the closer to the lower direction, i.e., the first negative direction X2 the direction faced by the outer peripheral surface Pl. In the present embodiment, the entire outer peripheral surface Pl is the first torsion surface. Figure 3 In the example shown, the closer the outer peripheral surface Pl faces the lower direction, i.e., the first negative direction X2, the closer to the lower direction, i.e., the first negative direction X2 the direction faced by the outer peripheral surface Pl. In the present embodiment, the entire outer peripheral surface Pl is the first torsion surface.

[0037] Specifically, a position of the curved portion 202 that is farthest from the end of the stator core 30, i.e., the first end 30a, is taken as a vertex Q. At the position of the vertex Q, the outer peripheral surface Pl faces a direction substantially opposite to the center axis CA, i.e., the outer direction. The direction faced by the outer peripheral surface Pl gradually approaches the direction facing the stator core 30 as it moves away from the vertex Q. That is, each of the curved portions 202 is twisted. At one curved portion 202 and another curved portion 202, the direction of the twist as viewed from the vertex Q becomes the opposite direction. The magnitude of the twist angle of the curved portion 202 is, for example, 90 degrees in the direction of one portion as viewed from the vertex Q, and 90 degrees at the portion in the other direction as viewed from the vertex Q.

[0038] As Figure 4As shown, each of the curved portions 202 of the second part 22B has four sides around the coil wire. The inner circumferential surface P2, one of these four sides, faces approximately inwards, towards the central axis CA. In other words, the inner circumferential surface P2 is the side facing one of the two directions along the orthogonal axis PL when viewed from the curved portion 202. At the second part 22B, the inner circumferential surface P2 has a second torsional surface. The closer the second torsional surface is to the end of the stator core 30, the closer the direction it faces is to the direction facing the stator core 30. That is, the closer the second torsional surface is to the intersection of the straight portion 201 and the curved portion 202, the closer the direction it faces is to the direction facing the stator core 30. Figure 4 In the example shown, the inner circumferential surface P2 of the second part 22B is more oriented towards Figure 4 If the inner circumferential surface P2 faces downwards, the direction it faces is closer to the bottom, i.e., the first negative direction X2.

[0039] Specifically, the inner circumferential surface P2 faces approximately inwards from the central axis CA at vertex Q. The direction facing the inner circumferential surface P2 gradually approaches the direction facing the stator core 30 as it moves away from vertex Q. That is, the curved portion 202 is twisted. Furthermore, at one curved portion 202 and another curved portion 202, the direction of twist as viewed from vertex Q becomes opposite. The magnitude of the twist angle of the curved portion 202 is, for example, 90 degrees in the direction of one portion as viewed from vertex Q, and 90 degrees in the other portion as viewed from vertex Q.

[0040] In addition, Figure 3 and Figure 4 In this diagram, while the shapes of the bent portions 202 are identical, the orientations of the inner and outer sides are reversed. Specifically, at the bent portions 202 of the coil end 22 in the first portion 22A and the second portion 22B, the directions of twisting of the bent portions 202 are opposite, resulting in a symmetrical shape. Furthermore, in... Figure 3 and Figure 4 In the middle, for the general Figure 1 The left end of the stator core 30 was described as the first end 30a, but regarding the... Figure 1 When the right end of the stator core 30 is designated as the first end 30a, it can also be configured such that the first torsional surface faces outward at vertex Q, and the second torsional surface faces inward at vertex Q. That is, it is not limited to the coil end 22 protruding from the first end 30a of the stator core 30; the first torsional surface and the second torsional surface can also be provided for the coil end 22 protruding from the second end 30b of the stator core 30.

[0041] like Figure 5As shown, the surface of the side face including the segment coil 21 has a plurality of pits 60. The pits 60 are circular depressions in plan view. The plurality of pits 60 are arranged at equal intervals. The diameter of each pit 60 is on the order of 0.1 to 1 mm. The depth of each pit 60 is on the order of 0.1 to 1 mm. The pits 60 are infinite in number for generating a so-called Magnus effect when oil flows on the surface of the segment coil 21. In addition, in Figure 3 and Figure 4 the illustration of the pits 60 is omitted.

[0042] <Effects of the Present Embodiment>

[0043] In the case where the oil in the cooling oil passage 50 is ejected from the injection hole 51 toward the coil end portion 22, the ejected oil is applied to the outer peripheral surface PI of the coil end portion 22 of the first portion 22A which is located in the second negative direction Y2 as viewed from the injection hole 51. The oil applied to the outer peripheral surface PI is mostly guided along the torsion surface toward the straight portion 201. That is, the oil is mostly guided in the direction of the stator core 30. The oil guided in the direction of the stator core 30 spreads along the stator core 30 to the entire stator core 30. A part of the oil that spreads along the stator core 30 propagates toward another segment coil 21 located in the second negative direction Y2. This phenomenon is repeated, and the oil spreads to the entire coil end portion 22 of the first portion 22A.

[0044] The oil that drips from the coil end portion 22 of the first portion 22A is applied to the inner peripheral surface P2 of the coil end portion 22 of the second portion 22B. The oil applied to the inner peripheral surface P2 of the second portion 22B is mostly guided along the torsion surface toward the straight portion 201. That is, the oil is mostly guided in the direction of the stator core 30. The oil guided in the direction of the stator core 30 spreads along the stator core 30 to the entire stator core 30. A part of the oil that spreads along the stator core 30 propagates toward another segment coil 21 located in the second negative direction Y2. This phenomenon is repeated, and the oil spreads to the entire second portion 22B of the coil end portion 22.

[0045] <Effects of the Present Embodiment>

[0046] (1) As a comparative example, assume that the oil applied to the segment coil 21 of the first portion 22A flows in the direction opposite to the stator core 30. In this case, the oil drips outside the stator core 20. Thus, since the oil dripped from a certain segment coil 21 is not applied to other segment coils 21, a sufficient cooling effect by the oil cannot be expected. Further, even if the oil drips on the coil end portion 22, if the oil cannot spread, an effect of cooling the entire coil end portion 22 cannot be achieved. In contrast, in the above embodiment, the oil injected to the segment coil 21 of the first portion 22A easily flows in the direction of the stator core 30. Thus, the amount of the oil that drips outside the stator 20 is reduced. The oil guided in the direction of the stator core 30 easily spreads to the entirety along the stator core 30. Since the oil drips along the plurality of segment coils 21, the coil end portion 22 is effectively cooled.

[0047] (2) In the above embodiment, since the oil that drips on the coil end portion 22 spreads along the twisted surface of the coil end portion 22, the oil contacts the segment coil 21 in a relatively long time. The oil contacts the segment coil 21 for a long time, and to that extent, heat exchange between the oil and the segment coil 21 is promoted.

[0048] (3) In the above embodiment, the oil that drips from the segment coil 21 of the first portion 22A hits the inner peripheral surface P2 of the segment coil 21 of the second portion 22B. The oil that hits the inner peripheral surface P2 of the segment coil 21 of the second portion 22B easily flows in the direction of the stator core 30. Thus, the amount of the oil that drips outside the stator 20 is reduced. The oil guided in the direction of the stator core 30 easily spreads to the entirety along the stator core 30. Since the oil drips along the plurality of segment coils 21, the coil end portion 22 is effectively cooled.

[0049] (4) In the above embodiment, each segment coil 21 is provided with the innumerable pits 60. Thus, the oil that flows along the segment coil 21 smoothly flows on the surface of the segment coil 21.

[0050] <Modification Example>

[0051] The present embodiment can be changed and implemented as described below. The present embodiment and the following modified examples can be implemented in combination with each other within a range in which they are not technically contradictory.

[0052] • In the above embodiment, the position of the injection hole 51 is not limited to directly above the coil end portion 22. As long as the injection hole 51 is located in the direction of the second positive direction Yl from the coil end portion 22, the above effect can be expected.

[0053] • In the above embodiment, the number of the injection hole 51 can be one, and further, a plurality of injection holes can be provided.

[0054] • In the above-described embodiment, the shape of the coil end portion 22 is not limited to the example of the above-described embodiment. In addition, the shape of the coil end portion 22 can be such that the coil end portion 22 in the direction of the first positive direction XI is different from the coil end portion 22 in the direction of the first negative direction X2. In this way, the segmented coil 21 constituting the first portion 22A of the coil end portion 22 can be applied to the technology related to the twist surface as long as the segmented coil 21 has the outer peripheral surface PI facing outward.

[0055] • In the above-described embodiment, it is not necessary that the entire outer peripheral surface PI of the first portion 22A becomes the twist surface. That is, it can be that a part of the outer peripheral surface PI becomes the twist surface. Similarly, it is not necessary that the entire outer peripheral surface P2 of the second portion 22B becomes the twist surface.

[0056] • The segmented coil 21 constituting the second portion 22B can not have the twist surface. As long as at least the segmented coil 21 constituting the first portion 22A has the twist surface, the effect of causing the oil to spread throughout the coil end portion 22 can be expected.

[0057] • In the above-described embodiment, the entire segmented coil 21 constituting the first portion 22A can not have the twist surface at the bent portion 202. That is, it is sufficient that at least a part of the segmented coil 21 has the twist surface.

[0058] • In the vicinity of the imaginary straight line VL, the segmented coil 21 having the twist surface in the same twist direction as the first portion 22A of the above-described embodiment and the segmented coil 21 having the twist surface in the same twist direction as the second portion 22B of the above-described embodiment can exist in mixture.

[0059] • In the above-described embodiment, the diameter and the depth of the recess 60 are not limited to the example of the above-described embodiment. For example, the segmented coil 21 can not have the recess 60.

Claims

1. A cooling system, wherein, The cooling system is equipped with: a rotating electric machine mounted on a vehicle; and a cooling oil passage through which oil flows, The rotating electric machine is equipped with: a stator core; and a plurality of segment coils mounted to the stator core, The stator core is equipped with: a circular ring-shaped core body having a central axis extending in a direction orthogonal to an axis extending in up and down directions of the vehicle; and a plurality of teeth extending from an inner peripheral surface of the core body toward the central axis, Each of the segment coils is inserted between the teeth, Each of the segment coils is equipped with a coil end portion that protrudes outward from a first end of the stator core in a direction along the central axis, The cooling oil passage is equipped with an injection hole for injecting oil toward the coil end portion, The injection hole is located above, as viewed from the coil end portion, A straight line that is orthogonal to both the central axis and an axis extending in the up and down directions when viewed in a direction along the central axis is referred to as an imaginary straight line, an upper portion among the coil end portions bisected by the imaginary straight line is referred to as a first portion, A portion of the segment coils that constitutes the first portion has an outer peripheral surface that faces toward a direction opposite to the central axis, as viewed from the portion of the segment coils that constitutes the first portion, An outer peripheral surface of the segment coil has a twist surface that is configured such that the closer to the first end of the stator core, the closer to a direction facing the stator core a direction in which the twist surface faces, A lower portion among the coil end portions bisected by the imaginary straight line is referred to as a second portion, A portion of the segment coils that constitutes the second portion has an inner peripheral surface that faces toward a direction opposite to the central axis, as viewed from the portion of the segment coils that constitutes the second portion, The twist surface of the outer peripheral surface of the segment coil is a first twist surface, The inner peripheral surface of the segment coil has a second twist surface that is configured such that the closer to the first end of the stator core, the closer to a direction facing the stator core a direction in which the second twist surface faces.

2. The cooling system according to claim 1, wherein The segment coils are equipped with a plurality of pits on surfaces of the segment coils, the pits being depressions that are circular in a plan view. The stator is equipped with:

3. A stator of a rotary electric machine, wherein a stator core; and a plurality of segment coils mounted to the stator core, The stator core is equipped with: a circular ring-shaped core body having a central axis; and a plurality of teeth extending from an inner peripheral surface of the core body toward the central axis, Each of the segment coils is inserted between the teeth, Each of the segment coils is equipped with a coil end portion that protrudes outward from a first end of the stator core in a direction along the central axis, A straight line that is orthogonal to the central axis when viewed in a direction along the central axis is referred to as an imaginary straight line, one portion among the coil end portions bisected by the imaginary straight line is referred to as a first portion, ​ ​ The portion of the segment coil that constitutes the first portion has an outer peripheral surface that faces in a direction opposite to the center axis from the portion of the segment coil that constitutes the first portion, The outer peripheral surface of the segment coil has a twisted surface that is configured such that the closer to the first end of the stator core, the closer to a direction facing the stator core the direction in which the twisted surface faces, The other of the coil end portions bisected by the imaginary straight line is referred to as a second portion, The portion of the segment coil that constitutes the second portion has an inner peripheral surface that faces in a direction toward the center axis from the portion of the segment coil that constitutes the second portion, The twisted surface of the outer peripheral surface of the segment coil is a first twisted surface, The inner peripheral surface of the segment coil has a second twisted surface that is configured such that the closer to the first end of the stator core, the closer to a direction facing the stator core the direction in which the second twisted surface faces.

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