JP2020014333A - Stator cooling structure - Google Patents

Abstract

To provide a stator cooling structure capable of efficiently cooling a stator core.SOLUTION: Disclosed stator cooling structure includes: a case having a cylindrical shape along the axis of the rotating electrical machine, which supports a stator core of the rotating electrical machine; and meandering cooling channel and meandering oil passage between the outer surface of the stator core and inner surface of the case. The cooling channel and oil passage have a first area adjacent to each other in the circumferential direction and a second area that crosses each other. At least one of the cooling channel and the oil passage has its dimension in the radial direction of the rotating electrical machine smaller in the second area than in the first area.SELECTED DRAWING: Figure 10

Description

  The present disclosure relates to a stator cooling structure for a stator of a rotating electric machine.

  A technique is known in which a gap is formed between a stator core and a stator holder in a radial direction of a rotating electric machine, in which a heat transfer body (cooling oil) is sealed or circulated, and a cooling water passage is formed in a housing. (See, for example, Patent Document 1).

JP 2010-273423 A

  However, it is difficult to efficiently cool the stator core with the above-described related art. The cooling oil is generally radiated by heat exchange with cooling water (for example, water containing LLC: Long Life Coolant) in an oil cooler. Therefore, the temperature of the cooling water is lower than that of the cooling oil. For this reason, when cooling oil is interposed between the cooling water and the stator core as in the above-described related art, it is difficult to efficiently cool the stator core.

  Therefore, in one aspect, an object of the present invention is to efficiently cool a stator core.

In one aspect, the case has a cylindrical shape along the axial direction of the rotating electric machine, and supports a stator core of the rotating electric machine;
Between the outer peripheral surface of the stator core and the inner peripheral surface of the case, a meandering cooling water passage and a meandering oil passage are included,
The cooling water passage and the oil passage have a first region adjacent in the circumferential direction of the rotating electric machine, and a second region crossing each other,
A stator cooling structure is provided in which at least one of the cooling water passage and the oil passage has a smaller dimension in a radial direction of the rotating electric machine in the second region than in the first region.

  According to one aspect, the present invention enables the stator core to be efficiently cooled.

It is a figure which shows an example of a vehicle drive device schematically. It is a figure showing roughly an example of composition of a lubrication / cooling system of a vehicle drive device. FIG. 2 is a perspective view showing an external appearance of a part of the motor. FIG. 4 is a perspective view of the holding ring viewed in the same direction as FIG. 3. It is a perspective view of the holding ring of a zenith part area. FIG. 4C is a plan view of the holding ring viewed from the X1 side in the X direction (see FIG. 4A). FIG. 4 is a sectional view of a part of the motor shown in FIG. 3. FIG. 7 is an enlarged view of a Q1 part in FIG. 6. It is sectional drawing of the end part of the X direction X2 side of a motor. It is sectional drawing which shows the relationship between a cooling water inlet part and an inlet waterway. It is a figure which shows the expansion | deployment state of a meandering waterway and a case oilway typically. FIG. 11 is a cross-sectional view along the line AA in FIG. 10. FIG. 11 is a cross-sectional view along a line BB in FIG. 10. It is explanatory drawing of a comparative example. It is sectional drawing which passes through the oil drop hole of an oil drop part. It is sectional drawing which passes through the oil drop hole of an oil drop part.

  Hereinafter, each embodiment will be described in detail with reference to the accompanying drawings. Here, first, a description will be given of a vehicle drive device and a lubrication / cooling system (a lubrication / cooling system including a stator cooling structure) to which the stator cooling structure can be applied, and then a heat exchange and water cooling unit according to the stator cooling structure. I do.

<Vehicle drive device>
FIG. 1 is a diagram schematically showing an example of a vehicle drive device 1 to which a stator cooling structure can be applied. FIG. 1 also shows drive wheels WL and WR.

  The vehicle drive device 1 is mounted on a vehicle. The vehicle drive device 1 includes a motor 10 (an example of a rotating electric machine), a speed reduction mechanism 12, and a differential device 14 connected to the output shaft 116 of the motor 10 via the speed reduction mechanism 12. The motor 10 generates a driving force for the vehicle. The motor 10 includes a rotor 10a and a stator 10b. The stator 10b includes a stator core 112 and a coil end 110 formed by a coil (not shown) mounted on the stator 10b. In addition, the stator core 112 may be formed of, for example, a laminated steel plate. The left and right drive wheels WL and WR are connected to the differential device 14. The differential device 14 includes a ring gear 140, a pinion gear 141, and a side gear 142. Further, the differential device 14 includes a differential case (not shown) that houses gears (the pinion gear 141, the side gear 142, and the like) inside. The configuration of the reduction mechanism 12 is not limited to the illustrated simple configuration, and may include a planetary gear mechanism. Each component (the motor 10, the speed reduction mechanism 12, the differential device 14, etc.) of the vehicle driving device 1 may be incorporated in a housing (not shown) as a single vehicle driving device unit, for example, or may be a plurality of components. It may be incorporated in another housing (not shown).

  The vehicle driving device 1 includes a lubrication / cooling system 3 for lubricating and / or cooling the motor 10, the speed reduction mechanism 12, and the differential device 14 using oil. Hereinafter, “lubrication / cooling” means at least one of lubrication and cooling.

  Note that a stator cooling structure 402 (see FIG. 2) according to an embodiment described later is applied to the motor 10 of the vehicle drive device 1 shown in FIG. 1 as an example. The present invention is also applicable to a motor included in a vehicle drive device having a configuration other than the device 1. That is, a stator cooling structure 402 described later can be applied to a vehicle drive device having an arbitrary configuration including a motor such as the motor 10. Further, the present invention is also applicable to a configuration including a generator (another example of a rotating electric machine) instead of the motor.

<Lubrication and cooling system>
FIG. 2 is a diagram schematically illustrating an example of a configuration of the lubrication / cooling system 3 of the vehicle drive device 1.

  The lubrication / cooling system 3 includes a tank 30, oil passages 31 to 36, an electric oil pump 40, a mechanical oil pump 42, a heat exchange and water cooling unit 50, a water pump 90, a radiator 92, And cooling water passages 94 and 95.

  The tank 30 is formed by a lowermost portion (a lowermost space in the vertical direction) in the housing of the vehicle drive device 1. The tank 30 is formed by, for example, an oil pan. The differential device 14 is disposed in the tank 30, and the differential device 14 is immersed in the oil in the tank 30. The differential device 14 is provided at a predetermined height predetermined with respect to the lower surface of the tank 30. The predetermined height is such that when the oil level of the tank 30 is equal to or higher than a predetermined height, the oil in the tank 30 enters the differential case with the rotation of the differential device 14 (the rotation of the differential case). It is determined that lubrication and cooling of the differential device 14 in a desired manner are realized. On the lower surface of the tank 30, a strainer 30a is provided.

  The oil passage 31 is provided between the tank 30 and the suction side of the electric oil pump 40. When the electric oil pump 40 operates, the oil in the tank 30 is sucked into the suction port of the electric oil pump 40 via the strainer 30a and the oil passage 31.

  The oil passage 32 is provided between the tank 30 and the suction side of the mechanical oil pump 42. When the mechanical oil pump 42 operates, the oil in the tank 30 is sucked into the suction port of the mechanical oil pump 42 via the strainer 30a and the oil passage 32. In addition, in the example shown in FIG. 2, the oil passage 32 has a common portion with the oil passage 31, but there is no such common portion, and the oil passage 32 may be formed independently of the oil passage 31.

  The oil passage 33 is provided between the discharge side of the electric oil pump 40 and the inlet side of the heat exchange and water cooling unit 50. The oil passage 33 guides oil discharged from the electric oil pump 40 to the heat exchange and water cooling unit 50. Therefore, the oil discharged from the electric oil pump 40 is supplied to the oil passage 36 after being cooled by the heat exchange and water cooling unit 50.

  The oil passage 34 is provided between the discharge side of the mechanical oil pump 42 and the tank 30. The oil passage 34 guides oil discharged from the mechanical oil pump 42 to the tank 30. The oil passage 34 may include an oil passage formed in a member such as a shaft of a speed reduction mechanism, or a simple space. The mere space is a space in the housing of the vehicle drive device 1. The oil from the oil passage 34 is used for lubrication in a member to be lubricated (the lubricating portion 22). The lubrication portion 22 is, for example, a bearing of the motor 10 or the like.

  The oil passage 35 is connected between the oil passage 33 and the oil passage 36 so as to pass through the heat exchange and water cooling unit 50. As will be described later, the oil in the oil passage 35 is cooled by a liquid refrigerant (cooling water) passing through the cooling water passage 95. The details of the oil passage 35 will be described later.

  The oil passage 36 is provided between the outlet side of the heat exchange and water cooling unit 50 and the tank 30. The oil passage 36 guides oil from the heat exchange and water cooling unit 50 to the tank 30. The oil passage 36 may be an oil passage formed in a member, such as an oil passage formed in a shaft of a speed reduction mechanism, an oil passage formed by a pipe, or the like. 10 includes a space within the housing (eg, case 70 of FIG. 3). In this case, the oil from the heat exchange and water cooling unit 50 is dropped by gravity, supplied to a member to be cooled (the cooling part 23), and then guided to the tank 30 by gravity. The cooling part 23 includes, for example, a coil end 110 (see FIG. 1) of the stator 10b of the motor 10.

  The electric oil pump 40 is driven by a dedicated drive source (not shown) such as a motor. The electric oil pump 40 discharges oil in the tank 30 to the oil passage 33 at the time of operation. That is, the electric oil pump 40 sucks the oil in the tank 30 through the oil passage 31 and discharges the oil to the oil passage 33 during operation. The oil discharged to the oil passage 33 is guided to the oil passage 36 via the heat exchange and water cooling unit 50. The electric oil pump 40 operates independently of the rotation of the wheels, and is an electrically operated oil pump. In addition, the electric oil pump 40 forms an oil circulation unit 400 that circulates oil through the oil passage 35 together with the tank 30, the oil passage 31, the oil passage 33, and the oil passage 36. Circulation section 400 may include other elements.

  When operated, the mechanical oil pump 42 sucks oil in the tank 30 through the oil passage 32 and discharges the oil to the oil passage 34. The mechanical oil pump 42 operates in accordance with the forward rotation of the wheels (forward rotation). The mechanical oil pump 42 may be provided for an arbitrary rotating member that rotates with the forward rotation of the wheel. For example, the mechanical oil pump 42 is provided on a counter shaft of the reduction mechanism 12 (see FIG. 1), and operates by forward rotation of the counter shaft of the reduction mechanism 12.

  The heat exchange and water cooling unit 50 has both a heat exchange function and a stator core water cooling function. Specifically, the heat exchange and water cooling unit 50 has a heat exchange function of realizing heat exchange between oil in the oil passage 35 and cooling water in the cooling water passage 95, and a stator core of the stator 10 b of the motor 10. It has a function of directly cooling 112 with cooling water (stator core water cooling function). The cooling water is, for example, water containing antifreeze or LLC (Long Life Coolant).

  The heat exchange and water cooling unit 50 also functions as an oil cooler, but is not the same as an oil cooler in that it has a function of cooling the stator core 112 of the motor 10 as a function other than the function of the oil cooler. Since the lubrication / cooling system 3 includes the heat exchange / water cooling unit 50, an oil cooler can be omitted. In this embodiment, the heat exchange and water cooling unit 50 is applied to the motor 10. The details of the heat exchange and water cooling unit 50 will be described later.

  The water pump 90 is a pump that circulates cooling water through the cooling water passages 94 and 95. In addition, the water pump 90 forms a cooling water circulation unit 401 that circulates cooling water through the cooling water passage 95 together with the radiator 92 and the cooling water passage 94. However, in a modified example, the cooling water circulation unit 401 includes other elements. May be. Further, the cooling water circulation unit 401 forms the stator cooling structure 402 together with the oil circulation unit 400 and the heat exchange and water cooling unit 50 described above. However, in a modified example, the stator cooling structure 402 may include other elements.

  The radiator 92 takes heat from the cooling water passing through the cooling water passages 94 and 95 to cool the cooling water. The radiator 92 may realize heat exchange between air (for example, air passing when the vehicle travels) and cooling water.

  The cooling water passage 94 guides the cooling water discharged from the water pump 90 to the cooling water passage 95 of the heat exchange and water cooling unit 50, and transfers the cooling water from the cooling water passage 95 of the heat exchange and water cooling unit 50 via the radiator 92 to a water pump. Return to 90. The radiator 92 may be provided between the water pump 90 and the heat exchange and water cooling unit 50.

  The cooling water passage 95 is formed in the heat exchange / water cooling unit 50. When the cooling water passes through the cooling water passage 95, the heat exchange function of the heat exchange and water cooling unit 50 and the stator core water cooling function described above can be realized. The details of the cooling water channel 95 will be described later.

  In the example shown in FIG. 2, the electric oil pump 40 and the mechanical oil pump 42 are provided, but one of the electric oil pump 40 and the mechanical oil pump 42 may be omitted. In this case, the lubrication part 22 and the cooling part 23 may be lubricated and cooled by oil from the other one (not omitted) of the electric oil pump 40 and the mechanical oil pump 42 without distinction.

  In the example shown in FIG. 2, the oil passage 33 may be branched and connected to the oil passage 34. In this case, the oil from the electric oil pump 40 is also supplied to the lubrication part 22. Alternatively, the oil passage 36 may be branched and connected to the oil passage 34. In this case, the oil from the heat exchange and water cooling section 50 is also supplied to the lubrication section 22. Alternatively, the oil passage 34 may be branched and connected to the oil passage 33. Further, the oil passage 34 may be connected to and integrated with the oil passage 36 on the downstream side of the lubrication section 22 and on the downstream side of the cooling section 23.

  In the example shown in FIG. 2, the cooling water passage 94 is connected only to the heat exchange and water cooling unit 50, but a member to be cooled, for example, an inverter (not shown) for driving the motor 10, It may be formed so as to pass through a high-voltage battery (not shown) or the like that drives the motor 10.

<Heat exchange and water cooling unit>
Next, the heat exchange and water cooling unit 50 applied to the motor 10 will be described with reference to FIG. In FIG. 3 and subsequent figures, from the viewpoint of maintaining the clarity of the drawings, a plurality of elements may be denoted by reference numerals only for some of the elements.

  FIG. 3 is a perspective view showing an external appearance of a part of the motor 10, and FIG. 4A is a perspective view of a holding ring 60 (an example of a cooling water channel forming member). FIG. 4B is a perspective view of the retaining ring 60 in the zenith region. FIG. 5 is a plan view of the holding ring 60 viewed from the X1 side in the X direction (see FIG. 4A). FIG. 6 is a sectional view of a part of the motor 10 shown in FIG. FIG. 7 is an enlarged view of a Q1 part in FIG. FIG. 3 does not show the rotor and the like of the motor 10.

  Hereinafter, the radial direction is based on the central axis I of the motor 10 (= the central axis of the stator core 112) unless otherwise specified. Note that the axial direction of the motor 10 corresponds to the X direction. In the following description, the up-down direction indicates the up-down direction when the motor 10 is mounted so that the center axis I is substantially parallel to the horizontal direction. The cross section in FIG. 6 is a cross section by a plane passing through the central axis I.

  The heat exchange and water cooling section 50 includes a holding ring 60 and a case 70. The heat exchange and water cooling section 50 forms an oil passage 35 (see FIG. 2) between the holding ring 60 and the case 70 in the radial direction. Hereinafter, the “oil passage 35” is referred to as “case oil passage 35”, and the structure of the case oil passage 35 will be described later. Further, the heat exchange and water cooling unit 50 includes a cooling water passage 95 (see FIG. 2) inside the holding ring 60. The structure of the cooling water passage 95 will be described later.

  The retaining ring 60 has a cylindrical shape as shown in FIGS. 4A and 4B. The retaining ring 60 is formed of a material having good thermal conductivity such as a metal. The holding ring 60 has a structure having a hollow portion (cavity) forming a cooling water passage 95 (see FIG. 2) as described later. The holding ring 60 having such a hollow portion may be manufactured by combining a plurality of parts, or may be formed by casting.

  As shown in FIGS. 4A and 6, the retaining ring 60 includes an annular bottom portion 62 (an example of a second portion) and a cylindrical portion 64 (a first portion of the first portion) extending from the outer peripheral edge of the bottom portion 62 in the X direction. Example). The bottom part 62 and the cylindrical part 64 may form an integral continuous part.

  As shown in FIG. 5, the retaining ring 60 has a hole 62a in the bottom surface portion 62 through which a rotor (not shown) penetrates. The hole 62a is formed, for example, in a circular shape around the center of the bottom portion 62 (the center through which the central axis I passes).

  As shown in FIG. 6, the holding ring 60 further has a through hole 62b in the bottom surface portion 62. The through hole 62b is used for fixing the holding ring 60 to the case 70 by bolts. The through hole 62b is formed with a diameter through which the shaft of the bolt BT (see FIG. 6) passes. A plurality of through holes 62b are provided along the circumferential direction. At this time, the through holes 62b are formed at equal intervals along the circumferential direction. The through-hole 62b is preferably located within a radial range that does not overlap the stator core 112 when viewed in the X direction, as shown in FIG. Thereby, workability when assembling the holding ring 60 to the case 70 with the stator core 112 attached to the holding ring 60 is improved. That is, a work space for fastening the bolt BT is formed on the outer peripheral side of the stator core 112, so that workability is improved.

  As shown in FIG. 5, the retaining ring 60 further has an oil outlet hole 62c in the form of a through hole in the bottom surface portion 62. The oil outlet hole 62c is an outlet hole for oil stored in a lower portion (oil storage space) of the motor 10, and is connected to the tank 30 (see FIG. 2). The oil outlet hole 62c is preferably located below the central axis I and within a radial range that overlaps the stator core 112 when viewed in the X direction, as shown in FIG. In this case, the oil outlet hole 62c can be arranged at a position that does not restrict the formation of the through hole 62b. The oil outlet hole 62c determines the highest position of the oil stored in the oil storage space, and is set such that the highest position of the oil is lower than the lowest position of the rotor 10a. That is, the oil outlet hole 62c may be formed such that the lower end is located at a height of about the difference between the inner and outer diameters of the stator core 112.

  As shown by a dotted line in FIG. 5, the holding ring 60 further has a cooling water inlet 62d and a cooling water outlet 62e on the X direction X2 side of the bottom surface 62. The cooling water inlet 62d and the cooling water outlet 62e communicate with an inlet water passage 951 and an outlet water passage 952 (both described below) formed in the bottom surface 62 from the X direction X2 side of the bottom surface 62. The cooling water inlet 62d and the cooling water outlet 62e are provided at substantially the same radial position and adjacent in the circumferential direction, as shown in FIG. 5, for example.

  As shown in FIG. 5, the holding ring 60 has bulging portions 62 f and 62 g that form an inlet water channel 951 and an outlet water channel 952 inside the bottom surface portion 62 in the X direction X1. The bulging portions 62f and 62g are provided on the opposite sides of the cooling water inlet 62d and the cooling water outlet 62e in the X direction.

  In addition, the inlet water channel 951 and the outlet water channel 952 are preferably formed so as to at least partially overlap with the oil sump space when viewed in the X direction, and more preferably, substantially entirely in the oil sump space when viewed in the X direction. Are formed to overlap. As described above, the oil reservoir space is a lower space whose highest position is defined by the oil outlet hole 62c in the radially inner space formed by the holding ring 60. In particular, it is preferable that the inlet water channel 951 be formed so as to overlap the oil reservoir space when viewed in the X direction. This is because the cooling water in the inlet water channel 951 is lower in temperature than the cooling water in the outlet water channel 952, and has a higher heat exchange capacity than the cooling water in the outlet water channel 952. Hereinafter, forming the inlet water passage 951 and the outlet water passage 952 so as to at least partially overlap the oil sump space as viewed in the X direction is also referred to as “overlap arrangement with the oil sump space as viewed in the X direction”. .

  Except for the end 640 of the cylindrical portion 64 on the X1 side in the X direction, a part of the radially outer surface (outer peripheral surface) of the cylindrical portion 64 has the diameter of the case oil passage 35 (see FIG. 2). A boundary surface 35b on the inside in the direction is formed. As shown in FIG. 7, the end 640 of the cylindrical portion 64 has a radially inner boundary of the case oil passage 35 (see FIG. 2) in order to secure necessary dimensions in the radial direction of the case oil passage 35. The outer diameter is larger than the surface 35b.

  As shown in FIG. 7, the retaining ring 60 has a seal groove 640a that is recessed radially inward on the outer peripheral surface of the end 640 of the cylindrical portion 64. The seal groove 640a extends over the entire circumference in the circumferential direction. The outer peripheral surface of the end portion 640 of the cylindrical portion 64 is in radial contact with the inner peripheral surface of the case 70 over the entire circumference in the circumferential direction. A seal member 640b such as an O-ring is mounted in the seal groove 640a. Thereby, between the case 70 and the holding ring 60 (the case oil passage 35) on the X direction X1 side of the cylindrical portion 64 is kept oil-tight.

  The holding ring 60 holds the stator core 112 radially inward in such a manner that the cylindrical portion 64 contacts the stator core 112 in the radial direction. That is, the retaining ring 60 retains the stator core 112 such that the inner peripheral surface of the cylindrical portion 64 contacts the outer peripheral surface of the stator core 112. For example, the retaining ring 60 is integrated with the stator core 112 by shrink fitting or the like. The retaining ring 60 is fixed to the case 70 by bolts while being integrated with the stator core 112. In this manner, the retaining ring 60 supports the stator 10b including the stator core 112 with respect to the case 70.

  The retaining ring 60 preferably retains the stator core 112 in such a manner that the inner peripheral surface of the cylindrical portion 64 contacts substantially the entire outer peripheral surface of the stator core 112. In this case, the entire stator core 112 can be efficiently cooled by the cooling water passing through the cooling water passage 95 in the retaining ring 60. In the present embodiment, as an example, as shown in FIG. 6, the holding ring 60 extends over the entire length of the stator core 112 in the X direction, and the inner peripheral surface of the cylindrical portion 64 contacts substantially the entire outer peripheral surface of the stator core 112. . The “substantially the entirety” of the outer peripheral surface of the stator core 112 refers to a location such as a welding groove (not shown) of the stator core 112 (the outer peripheral surface of the stator core 112 and the inner peripheral surface of the cylindrical portion 64 are radially separated from each other. This is a concept that allows for

  As shown in FIG. 6, in the holding ring 60, on the X2 side in the X direction, the cylindrical portion 64 extends beyond the coil end 110 in the X direction. On the other hand, in the present embodiment, as an example, as shown in FIG. 6, on the X1 side in the X direction, the cylindrical portion 64 is located in the X direction before the end of the coil end 110 (the end on the X1 side). Extend to. However, in the modified example, the holding ring 60 also has the cylindrical portion 64 extending to the end of the coil end 110 (the end on the X1 side) or beyond the end in the X direction on the X1 side. Is also good.

  As shown in FIG. 6, the holding ring 60 has the bottom surface portion 62 facing the end surface of the stator core 112 on the X direction X2 side in the X direction on the X2 side. At this time, in the present embodiment, as an example, the holding ring 60 has the bottom surface portion 62 separated in the X direction from the end of the stator 10b on the X direction X2 side (the end surface of the coil end 110 on the X direction X2 side). While facing each other. At this time, the separation distance may correspond to a required insulation distance between the coil end 110 and the holding ring 60.

  As shown in FIGS. 4A and 4B, the retaining ring 60 includes a partition wall 64a, a first ridge 641, a second ridge 642, and a third ridge 643 on the outer peripheral surface of the cylindrical portion 64. And a fourth ridge 644 and a fifth ridge 645.

  The partition wall 64a is a ridge that extends linearly in the X direction. The partition wall 64a has a function of partitioning first oil passage portions 3501 (described later) formed on both sides in the circumferential direction. The partition wall 64a may have a hollow portion (hollow), but the hollow portion does not form an oil passage or a water passage. The partition wall 64 a extends on the X2 side to the extreme end, and the X direction X1 side extends to the end 640 of the cylindrical portion 64. The radially outer surface of the partition wall 64a may be continuous with the radially outer surface of the end 640 of the cylindrical portion 64. The partition wall 64a is disposed, for example, below the first ridge 641, the second ridge 642, the third ridge 643, the fourth ridge 644, and the fifth ridge 645. .

  The first ridge portion 641, the second ridge portion 642, the third ridge portion 643, and the fourth ridge portion 644 are formed in a region other than the zenith region of the holding ring 60. The fifth protrusion 645 is formed in the zenith region of the retaining ring 60. Note that the zenith region of the retaining ring 60 indicates the highest position of the retaining ring 60 and its peripheral region. For example, the zenith region may be, for example, a range of about 120 degrees in the circumferential direction around the circumferential position corresponding to the highest position.

  The first protrusion 641 extends linearly in the X direction as shown in FIG. 4A. The first protrusion 641 includes a hollow portion (hollow), and the hollow portion forms a part of the cooling water passage 95 (described later). The first protruding ridge portion 641 extends in the X direction X2 side to the extreme end, and extends in the X direction X1 side by a predetermined distance L1 (see FIG. 4A) before the end portion 640 of the cylindrical portion 64. The radially outer surface of the first protrusion 641 is flush with the radially outer surface of the end 640 of the cylindrical portion 64. The predetermined distance L1 is a value that determines a flow path width of a meandering water channel 950 (see FIG. 10), which will be described later, and may be determined from the viewpoint of increasing the heat exchange ability by the flow of the cooling water in the meandering water channel 950.

  The second protrusion 642 extends linearly in the X direction, as shown in FIG. 4A. The second ridge portion 642 includes a hollow portion (cavity), and the hollow portion forms a part of the cooling water passage 95 (described later). The second protrusion 642 extends in the X direction X2 side to the near side by a predetermined distance L2 (see FIG. 4A) from the end, and the X direction X1 side extends to the end 640 of the cylindrical portion 64. The radially outer surface of the second protrusion 642 is flush with the radially outer surface of the end 640 of the cylindrical portion 64. The predetermined distance L2 may be the same as the predetermined distance L1.

  Here, the first ridges 641 and the second ridges 642 are provided alternately in the circumferential direction at a constant angle α (not shown) in a region other than the zenith region of the holding ring 60. The circumferential extension range (peripheral length) of one first ridge 641 may be the same as the circumferential extension range of one second ridge 642. β (not shown). The angle β may be the same as the constant angle α. Note that the predetermined distance L1 may be the same as the circumference of one first ridge 641.

  As shown in FIG. 4A, the third ridge 643 is continuous with the end of the first ridge 641 in the X direction X1 side in the X direction, extends in the X direction X1 side in the circumferential direction, and extends in the second direction. It continues to the circumferential side of the ridge 642. The third ridge portion 643 has a hollow portion (hollow), and the hollow portion forms a part of the cooling water channel 95 (described later). The hollow portion of the third ridge portion 643 is continuous with the hollow portion of the first ridge portion 641 in the X direction, and is continuous with the hollow portion of the second ridge portion 642 in the circumferential direction.

  The third ridge 643 near the zenith region is continuous with the fifth ridge 645 in the circumferential direction instead of the second ridge 642 in the circumferential direction. The hollow portion of the third ridge portion 643 near the zenith region is continuous with the hollow portion of the first ridge portion 641 in the X direction, and is continuous with the hollow portion of the fifth ridge portion 645 in the circumferential direction.

  As shown in FIG. 4A, the third protrusion 643 has a width in the X direction that is a predetermined distance L1, and is adjacent to the end 640 from the X1 side. The radially outer surface of the third ridge 643 is radially inner than the radially outer surface of the first ridge 641. That is, the height (radial dimension) H2 of the third ridge 643 is lower than the height H1 of the first ridge 641 (= the height of the second ridge 642). For example, the height H2 of the third ridge 643 is substantially half the height H1 of the first ridge 641.

  The radially outer surface of the third ridge portion 643 forms a part of a radially inner boundary surface 35b of the case oil passage 35 (see FIG. 2).

  As shown in FIG. 4A, the fourth ridge portion 644 is continuous with the end of the second ridge portion 642 on the X direction X2 side in the X direction, extends circumferentially on the X direction X2 side, and The ridge 641 is continuous with the side in the circumferential direction. The fourth ridge portion 644 includes a hollow portion (cavity), and the hollow portion forms a part of the cooling water passage 95 (described later). The hollow portion of the fourth ridge portion 644 is continuous with the hollow portion of the second ridge portion 642 in the X direction, and is continuous with the hollow portion of the first ridge portion 641 in the circumferential direction.

  The fourth ridge 644 in the vicinity of the zenith region is continuous with the circumferential side of the fifth ridge 645 instead of the circumferential side of the first ridge 641. The hollow portion of the fourth ridge portion 644 near the zenith region is continuous with the hollow portion of the second ridge portion 642 in the X direction, and is continuous with the hollow portion of the fifth ridge portion 645 in the circumferential direction.

  The fourth ridge portion 644 has a width in the X direction at a predetermined distance L2, and extends in the circumferential direction in a manner to form an end portion on the X2 side in the X direction. The radially outer surface of the fourth ridge 644 is radially inner than the radially outer surface of the first ridge 641. That is, the height (radial dimension) of the fourth protruding portion 644 is lower than the height of the first protruding portion 641 (= the height of the second protruding portion 642). For example, the height of the fourth protrusion 644 may be the same as the height of the third protrusion 643.

  The radially outer surface of the fourth protrusion 644 forms a part of a radially inner boundary surface 35b of the case oil passage 35 (see FIG. 2).

  As shown in FIG. 4B, the fifth protrusion 645 extends in an S shape, one end extends to an end 640 of the holding ring 60, and the other end extends to the X2 side of the holding ring 60 in the X direction. Extends to the end. The fifth protrusion 645 includes a hollow portion (hollow), and the hollow portion forms a part of the cooling water passage 95 (described later). The hollow portion of the fifth ridge portion 645 is continuous with the hollow portion of the third ridge portion 643 on one end side, and is continuous with the hollow portion of the fourth ridge portion 644 on the other end side.

  The U-shaped portion of the S-shape of the fifth ridge 645 that opens on the X1 side in the X direction is closer to the X2 side by a predetermined distance L3 (see FIG. 4B) than the outermost end of the cylindrical portion 64. Extend to. Further, of the S-shape of the fifth protrusion 645, the U-shaped portion that is open on the X2 side is a predetermined distance L4 on the X1 side more than the end of the cylindrical portion 64 (see FIG. 4B). Only extend to the front. The predetermined distance L3 and the predetermined distance L4 are determined corresponding to the formation areas of the oil dropping portions 356 and 358 described later. Note that, of the S-shape of the fifth ridge 645, a U-shaped portion that opens on the X1 side is circumferentially connected to the third ridge 643 on the X1 side in the X direction. The U-shaped portion of the S-shape of the fifth ridge 645 that opens on the X2 side is circumferentially connected to the fourth ridge 644 on the X2 side in the X direction.

  As shown in FIG. 4A and as described above, the retaining ring 60 has the above-described partition wall 64a, the first ridge 641, and the third ridge 643 on the outer peripheral surface of the cylindrical portion 64, and thus has a circumferential direction. A concave groove 646 is formed between the partition wall 64a, the first ridge 641, and the third ridge 643. Each of the concave grooves 646 formed on both sides of the partition wall 64a in the circumferential direction communicates with the oil inlet 35a (see FIG. 8) of the case oil passage 35 at the end on the X2 side in the X direction. The partition wall 64a is located in the lowermost region of the holding ring 60. The lowermost region of the retaining ring 60 represents the lowest position of the retaining ring 60 and a region in the vicinity thereof. The lowermost region may be, for example, a range of about 60 degrees in the circumferential direction around the circumferential position corresponding to the lowest position.

  Further, as shown in FIG. 4A and described above, the holding ring 60 has the above-described first ridge 641, second ridge 642, and fourth ridge 644 on the outer peripheral surface of the cylindrical portion 64. Therefore, a concave groove 647 is formed between the first protrusion 641 and the second protrusion 642 and the fourth protrusion 644 in the circumferential direction. Further, as shown in FIG. 4B and as described above, since the retaining ring 60 has the above-described fifth ridge 645 on the outer peripheral surface of the cylindrical portion 64 in the zenith region, the fifth ridge 645 is not provided. Recessed grooves 648 and 649 are formed in the formation region. The concave groove 648 is adjacent to the fifth ridge 645 on the X direction X2 side, and the concave groove 649 is adjacent to the fifth ridge 645 in the X direction X1. A part of the radially inner boundary surface 35b of the concave grooves 646 to 649 is formed. Therefore, the concave grooves 646 to 649, the third ridge 643, and the fourth ridge 644 form a boundary surface 35b, and the boundary surface 35b is a meandering shape extending in the circumferential direction while moving back and forth in the X direction. Becomes

  The case 70 is formed of, for example, a metal such as aluminum. The case 70 may be formed by combining two or more parts. The case 70 supports the holding ring 60 radially inward. That is, the case 70 is provided so as to cover the outside of the cylindrical portion 64 of the holding ring 60 in the radial direction, and supports the holding ring 60. The holding ring 60 may be supported in any manner, but preferably, the case 70 is held by a bolt BT (an example of a fixing member) passing through a through hole 62b of the bottom surface 62 of the holding ring 60, as shown in FIG. The ring 60 is supported. That is, the retaining ring 60 is fixed to the case 70 by the bolt BT. Thereby, for example, the diameter of the motor 10 can be easily reduced as compared with the case where the holding ring 60 includes a mounting portion (a portion to be bolted to the case) protruding radially outward.

  The case 70 forms a case oil passage 35 (see FIGS. 2 and 10) between the case 70 and the holding ring 60 in the radial direction. The case 70 has an inner peripheral surface (a radially inner surface) radially opposed to the outer peripheral surface of the cylindrical portion 64 of the holding ring 60. The inner peripheral surface of the case 70 is, for example, a surface having no irregularities, and forms a radially outer boundary surface 35c of the case oil passage 35 (see FIGS. 2 and 7).

  Next, the cooling water passage 95 (see FIG. 2) formed by the holding ring 60 and the case oil passage 35 formed between the holding ring 60 and the case 70 will be described in detail.

  The cooling water channel 95 is connected to the case water channels 942 and 944. More specifically, the upstream end of the cooling water passage 95 is connected to the case water passage 942, and the downstream end of the cooling water passage 95 is connected to the case water passage 944.

  FIG. 8 is an explanatory diagram of the case water channels 942 and 944 in the case 70, and is a cross-sectional view when the end of the motor 10 on the X2 direction X2 side is cut along a plane perpendicular to the central axis I. FIG. 9 is a cross-sectional view showing the relationship between the cooling water inlet 62d and the inlet water passage 951. FIG. 8 also shows an inlet oil passage 330 of the case oil passage 35 to the oil inlet portion 35a. The inlet oil passage 330 forms the oil passage 33 (see FIG. 2). The inlet oil passage 330 is formed in such a manner as to branch on the way to form two oil inlet portions 35a connected to the retaining ring 60. FIG. 8 also shows an outlet oil passage 360 connected to the oil outlet hole 62c. The outlet oil passage 360 forms the oil passage 36 (see FIG. 2).

  The case water channels 942, 944 are formed in the case 70 and extend radially inward from the outer peripheral surface of the case 70 to a position short of the bolt hole 32b for the bolt BT. The case water channels 942 and 944 extend in the X direction from near the radially inner end to the X direction X1 side (see FIG. 9 for the case water channel 942). The case water channel 942 is a flow channel connected to the discharge side of the water pump 90, and the case water channel 944 is a flow channel connected to the suction side of the water pump 90. The case channels 942 and 944 are connected to an inlet channel 951 and an outlet channel 952, respectively, at ends on the X1 side in the X direction.

  As shown in FIG. 9, when the cooling water is introduced into the holding ring 60 from the cooling water inlet 62d (see arrow R0), it flows radially outward in the inlet water passage 951 (see arrow R1), and the holding ring At a corner of 60 (a corner formed by the bottom portion 62 and the cylindrical portion 64), the flow direction is changed by 90 degrees (toward the X direction) and introduced into a meandering water channel 950 (described later) in the cylindrical portion 64. (See arrow R2).

  The cooling channel 95 includes a meandering channel 950, an inlet channel 951 (see FIG. 5), and an outlet channel 952 (see FIG. 5).

  The meandering channel 950 is formed in the cylindrical portion 64 of the holding ring 60. The meandering water channel 950 is formed so that the cooling water flows in the circumferential direction while moving back and forth in the X direction. The inlet channel 951 and the outlet channel 952 are formed on the bottom surface 62 of the holding ring 60 as described above. The meandering channel 950 has one end connected to the inlet channel 951 and the other end connected to the outlet channel 952. Details of the meandering water channel 950 will be described later with reference to FIG.

  As described above, the case oil passage 35 is defined by the radially inner boundary surface 35b and the radially outer boundary surface 35c in the radial direction. Since the boundary surface 35b is formed by the radially outer surfaces of the concave grooves 646 to 649, the third ridge 643, and the fourth ridge 644, the case oil passage 35 has a meandering shape. In addition, since the concave groove 648 and the concave groove 649 (see FIG. 4B) are not directly connected, the case oil passage 35 includes two meandering oil passages. The meandering mode of the case oil passage 35 will be described later with reference to FIG.

  As shown in FIG. 4B, the case oil passage 35 has oil dropping portions 356 and 358 in the zenith region of the holding ring 60. The oil dropping portion 356 is formed by an end of the concave groove 648 on the X2 side in the X direction. The oil dropping portion 356 has an oil dropping hole 3561 penetrating in the radial direction. The number of the oil dropping holes 3561 is arbitrary, but in the present embodiment, as an example, three oil dropping holes 3561 are formed. That is, as shown in FIG. 4B, three oil drop holes 3561 are formed at equal intervals in the circumferential direction. The oil dropping hole 3561 is formed at the end of the oil dropping portion 356 on the X1 side. In other words, the oil dropping portion 356 is restricted to the range in which the meandering channel 950 is formed. Therefore, the oil dropping portion 356 is formed in the minimum range in the X direction in order to maximize the range in which the meandering channel 950 is formed.

  The oil dropping portion 358 is formed by an end of the concave groove 649 on the X1 side in the X direction. An oil drop hole 3581 penetrating in the radial direction is formed in the oil drop section 358. The number of the oil drop holes 3581 is arbitrary, but in the present embodiment, as an example, three oil drop holes 3581 are formed. That is, as shown in FIG. 4B, three oil drop holes 3581 are formed at equal intervals in the circumferential direction.

  FIG. 10 is an explanatory diagram of a meandering form of the meandering water channel 950 and the case oil passage 35, and is a diagram schematically illustrating a developed state of the meandering water passage 950 and the case oil passage 35. That is, FIG. 10 is a diagram schematically illustrating a state of the cooling water passage 95 and the case oil passage 35 when the cylindrical shape of the holding ring 60 is developed in a planar shape. FIG. 10 is a diagram viewed from the outside in the radial direction. In FIG. 10, the entry of oil is indicated by “oil IN”, and the entrance and exit of the cooling water are indicated by “water IN” and “water OUT”. Since FIG. 10 is a schematic diagram, the relationship of the width of each channel and the like may be different from that of FIG.

  The meandering channel 950 has a hollow portion (cavity) of each of the first ridge portion 641, the second ridge portion 642, the third ridge portion 643, the fourth ridge portion 644, and the fifth ridge portion 645 described above. Formed by The meandering water channel 950 is formed in the cylindrical portion 64 of the holding ring 60 so as to move back and forth in the X direction. That is, the meandering water channel 950 extends from the X direction X2 side of the retaining ring 60 to the X direction X1 side, and then turns back to extend from the X direction X1 side to the X direction X2 side, and then turns back to the X direction X2 side. It extends in the circumferential direction while meandering, extending from the side to the X direction X1 side. At this time, the meandering water channel 950 is formed so that the cooling water flowing through the meandering water channel 950 can take heat from the entire stator core 112 in the X direction of the stator core 112. In the present embodiment, as an example, the meandering water channel 950 is formed so as to move back and forth over the entire holding ring 60 in the X direction, except for a range in which oil drop portions 356 and 358 described later are formed. In other words, the length of the retaining ring 60 in the X direction is determined according to the range in which the meandering channel 950 is formed in the X direction.

  More specifically, as shown in FIG. 10, the meandering water channel 950 includes a plurality of first flow passages 9501 extending in the X direction, and a plurality of first flow passages 9501 that are circumferentially formed at ends in the X direction. A second flow path portion 9502 connected in the direction and an S-shaped third flow path portion 9503 are included.

  The meandering channel 950 is formed in a mode in which the plurality of first flow paths 9501 are connected via the second flow path 9502 in a region other than the zenith region of the retaining ring 60. At this time, the “meandering” is realized by alternately arranging the second flow path portions 9502 on the X1 side and the X2 side along the circumferential direction. That is, one second flow passage portion 9502 and two first flow passage portions 9501 connected to both sides (both circumferential sides) form a U-shaped flow passage, and the U-shaped flow passage is formed. The direction of the flow path is reversed in the X direction each time one second flow path portion 9502 changes one by one in the circumferential direction.

  The meandering channel 950 has an S-shaped third channel portion 9503 in the zenith region of the retaining ring 60. The S-shaped third channel portion 9503 is connected to the second channel portion 9502 so as to take over the meandering shape formed by the first channel portion 9501 and the second channel portion 9502.

  Out of the plurality of first flow passages 9501, two first flow passages 9501-1 and 9501-12 lower than the other are each a first flow passage 9501 closest to the cooling water inlet 62d. And the first flow path 9501 closest to the cooling water outlet 62e. This facilitates the overlapping arrangement of the above-described inlet water passage 951 and outlet water passage 952 with the oil reservoir space as viewed in the X direction. Note that, unlike the other first flow passage portions 9501, the first flow passage portion 9501-1 and the first flow passage portion 9501-12 are formed only at one end (the end in the X direction X1 side in this example). It is not connected to the two flow path section 9502.

  When the cooling water is introduced from the inlet side of the meandering water channel 950, the cooling water flows in the circumferential direction while meandering, and exits from the outlet side. During this time, heat exchange with the oil in the case oil passage 35 is realized as described later, and the oil is cooled.

  The case oil passage 35 is formed in such a manner as to move back and forth in the X direction in a manner adjacent to the meandering water passage 950 in the circumferential direction.

  That is, the case oil passage 35 extends from the X direction X2 side of the retaining ring 60 to the X direction X1 side, then turns back to extend from the X direction X1 side to the X direction X2 side, and then turns back to the X direction X2 side. It extends in the circumferential direction while meandering, for example, extending from the X2 side to the X direction X1 side. In this case, the first meandering oil passage 35-1 of the case oil passage 35 guides the oil introduced from the lowermost region to the oil dropping portion 356. The second meandering oil passage 35-2 of the case oil passage 35 guides the oil introduced from the lowermost region to the oil dropping portion 358. The first system meandering oil passage 35-1 and the second system meandering oil passage 35-2 do not communicate with each other.

  More specifically, as shown in FIG. 10, the case oil passage 35 includes a plurality of first oil passages 3501 extending in the X direction and ends of the plurality of first oil passages 3501 in the X direction. And a second oil passage portion 3502 connected in the circumferential direction.

  The first meandering oil passage 35-1 is formed in such a manner that a plurality of first oil passages 3501 are connected via a second oil passage 3502 until reaching the oil dropping portion 356. At this time, the “meandering” is realized by alternately arranging the second oil passage portions 3502 on the X1 side and the X2 side along the circumferential direction. Further, the meandering oil passage 35-2 of the second system is formed in such a manner that a plurality of first oil passages 3501 are connected via the second oil passage 3502 until reaching the oil dropping portion 358. At this time, the “meandering” is realized by alternately arranging the second oil passage portions 3502 on the X1 side and the X2 side along the circumferential direction.

  Of the plurality of first oil passage portions 3501, two first oil passage portions 3501 lower than the other (first oil passage portions 3501 adjacent to the partition wall 64a in the circumferential direction) are each provided with an oil inlet portion. 35a (first and second oil inlet portions 35a).

  Here, the cooling water passage 95 and the case oil passage 35 have an intersecting region P1 that intersects each other as shown by a rectangle surrounded by a dotted line in FIG. The cooling water passage 95 and the case oil passage 35 have an intersection area P1 at an end in the X direction. In the intersection area P1, the cooling water passage 95 and the case oil passage 35 have reduced radial dimensions and are adjacent in the radial direction. Specifically, the intersection area P1 is realized by the third ridge 643 and the fourth ridge 644 described above with reference to FIG. 4A. The third ridge 643 and the fourth ridge 644 are lower than the heights of the first ridge 641 and the second ridge 642 as described above. Therefore, in the cooling water channel 95, a flow path portion formed by each hollow portion of the third ridge portion 643 and the fourth ridge portion 644 is formed by each of the first ridge portion 641 and the second ridge portion 642. The size in the radial direction is reduced as compared with the flow path portion formed by the hollow portion. The radially outer surfaces of the third ridges 643 and the fourth ridges 644 extend radially outward from the bottom surfaces of the grooves 646 to 649. Therefore, the oil passage portion of the case oil passage 35 whose radially inner boundary surface is formed by the radially outer surfaces of the third ridge 643 and the fourth ridge 644 is the radially inner surface. The dimension in the radial direction is smaller than that of the oil passage portion whose boundary surface is formed by the bottom surfaces of the grooves 646 to 649.

  The amount of reduction in the radial dimension of each of the cooling water passage 95 and the case oil passage 35 in the intersection region P1 may be about half of the respective radial dimensions of the cooling water passage 95 and the case oil passage 35 in the other region. . That is, the radial dimension of each of the cooling water passage 95 and the case oil passage 35 in the intersection region P1 may be approximately half of the radial dimension of each of the cooling water passage 95 and the case oil passage 35 in the other region. Thereby, even in the intersection region P1 where the cooling water passage 95 and the case oil passage 35 intersect with each other, the same size (the radial size of the cooling water passage 95 and the case oil passage 35 as a whole) can be maintained.

  Next, a mode of heat exchange between oil in the case oil passage 35 and cooling water in the meandering water passage 950 will be described with reference to FIGS. 11 and 12. FIG. 11 is a sectional view taken along line AA in FIG. 10, and FIG. 12 is a sectional view taken along line BB in FIG. 11 and 12, the plate thickness of the holding ring 60 is not shown (represented by a line) for simplification, and a part of the stator core 112 is schematically shown for convenience of explanation. FIGS. 11 and 12 show the inner wall surface portion 651 that contacts the stator core 112 and the radial wall surface that contacts the case oil passage 35 in the radial direction, among the wall surfaces of the retaining ring 60 that define the meandering water channel 950. A portion 652 and a circumferential wall portion 656 are shown.

  In a region where the meandering water channel 950 and the case oil passage 35 are adjacent to each other in the circumferential direction (an example of a first region), as shown in FIG. 11, between the oil in the case oil passage 35 and the cooling water in the meandering water channel 950. Thus, heat exchange in the circumferential direction can be realized (see arrow Q2 in FIGS. 11 and 12). In the circumferential direction, between the oil in the case oil passage 35 and the cooling water in the meandering water passage 950, only the wall surface portion 656 of the retaining ring 60 exists as a partition wall surface. As compared with the above, more efficient heat exchange can be realized. As a result, the oil in the case oil passage 35 can be efficiently cooled by the cooling water in the meandering water passage 950.

  In the intersection area P1 (an example of a second area) where the meandering water channel 950 and the case oil passage 35 intersect, the meandering water channel 950 and the case oil passage 35 are adjacent to each other in the radial direction. Therefore, in the intersection area P1, heat exchange in the radial direction can be realized between the oil in the case oil passage 35 and the cooling water in the meandering water passage 950 (see arrow Q3 in FIG. 12). In the radial direction, between the oil in the case oil passage 35 and the cooling water in the meandering water passage 950, only the wall surface portion 652 of the retaining ring 60 exists as a partition wall surface. As compared with the above, more efficient heat exchange can be realized. As a result, the oil in the case oil passage 35 can be efficiently cooled by the cooling water in the meandering water passage 950, and the oil can be efficiently cooled before reaching the oil dropping portions 356 and 358.

  In addition, a region where the meandering water channel 950 and the case oil channel 35 are adjacent in the X direction (an example of a third region), that is, a region including the end of the fifth ridge 645 on the X2 side and the oil dripping portion 356. In the region including the end of the fifth protrusion 645 on the X1 side in the X direction and the oil dropping portion 358, heat exchange in the X direction between the oil in the case oil passage 35 and the cooling water in the meandering water passage 950. (Not shown). Between the oil in the case oil passage 35 and the cooling water in the meandering water passage 950 in the X direction, the wall portions 653 and 654 (see FIGS. 14 and 15) of the retaining ring 60 only exist as partition walls. Therefore, efficient heat exchange can be realized as compared with the case where another member or the like is interposed. As a result, the oil in the case oil passage 35 (in particular, the oil in the oil dropping portions 356 and 358) can be efficiently cooled by the cooling water in the meandering water passage 950.

  Here, the effect of this embodiment will be described in comparison with a comparative example shown in FIG. FIG. 13 shows the meandering water passage 950A and the meandering oil passage 35A according to the comparative example in a partially expanded state. In the comparative example, since the meandering water passage 950A and the meandering oil passage 35A do not intersect, radial heat exchange in the intersection region cannot be realized. Further, in the comparative example, since the meandering water channel 950A cannot be adjacent to the meandering oil passage 35A on both sides in the circumferential direction, heat exchange in the circumferential direction is not efficient.

  In this regard, according to this embodiment, the heat exchange in the radial direction can be realized as described above, and the first oil passage of the case oil passage 35 on both sides of the first flow passage 9501 of the meandering water passage 950 in the circumferential direction. Since the portion 3501 is adjacent, the cooling capacity can be increased as compared with the comparative example shown in FIG.

  Next, how the coil end 110 is cooled by oil reaching the oil dropping portions 356 and 358 will be described.

  FIG. 14 is a cross-sectional view taken along a plane passing through the oil dropping hole 3561 of the oil dropping portion 356 and including the central axis I. FIG. 15 is a cross-sectional view taken along a plane passing through the oil drop hole 3581 of the oil drop section 358 and including the central axis I.

  The oil dropping portions 356 and 358 are formed in the zenith region of the holding ring 60 and at a position facing the coil end 110 in the radial direction. The oil dropping portion 356 is provided for the coil end 110 on the X direction X2 side, and the oil dropping portion 358 is provided for the coil end 110 on the X direction X1 side.

  The oil that has reached the oil dropping portion 356 is dropped from the oil dropping hole 3561 (see the arrow R25 in FIG. 14), and cools the coil end 110 immediately below. Similarly, the oil that has reached the oil dropping portion 358 is dropped from the oil dropping hole 3581 (see the arrow R26 in FIG. 15), and cools the coil end 110 immediately below. The oil used for cooling the coil end 110 flows downward by gravity while traveling along the coil end 110, and accumulates in the lower portion (oil storage space) of the motor 10. Oil accumulated in the oil sump space is discharged from the oil outlet hole 62c to the outside of the motor 10 via the outlet oil passage 360 (see FIG. 8). The oil stored in the oil storage space also has a function of cooling a portion of the stator 10b that is immersed in the oil (including a part of the coil end 110).

  According to the stator cooling structure 402 according to the present embodiment described above, the following effects are particularly obtained.

  According to the stator cooling structure 402 according to the present embodiment, since the retaining ring 60 forms the meandering channel 950, heat can be taken over a wide area of the stator core 112 by the cooling water flowing through the meandering channel 950. In particular, according to the stator cooling structure 402 according to the present embodiment, as described above, the meandering water passage 950 is formed so as to move back and forth over the entirety of the stator core 112 in the X direction. Can be.

  Further, according to the stator cooling structure 402 according to the present embodiment, since the meandering water passage 950 and the case oil passage 35 are adjacent in the circumferential direction, heat can be exchanged between the oil and the cooling water flowing through the meandering water passage 950. Only the circumferential wall surface portion 656 (see FIGS. 11 and 12) of the retaining ring 60 exists between the first flow passage portion 9501 and the first oil passage portion 3501 that are adjacent in the circumferential direction. Therefore, the oil can be efficiently cooled by the cooling water as compared with a case where, for example, another member, a cavity, or the like is interposed between the first flow passage portion 9501 and the first oil passage portion 3501 which are adjacent in the circumferential direction. .

  Further, according to the stator cooling structure 402 according to the present embodiment, since the meandering water passage 950 and the case oil passage 35 have the intersecting region P1, the radial heat between the cooling water and the oil in the intersecting region P1. Exchange can be realized. In particular, in the intersecting region P1, only the radially outer wall portion 652 (see FIG. 12) of the retaining ring 60 exists between the cooling water and the oil in the radial direction. Therefore, the oil can be efficiently cooled by the cooling water as compared with a case where, for example, another member, a cavity, or the like is interposed between the cooling water and the oil.

  Further, according to the stator cooling structure 402 according to the present embodiment, since the meandering water passage 950 and the case oil passage 35 have the intersecting region P1, as described above, the first flow passage portion 9501 of the meandering water passage 950 and the case The first oil passage portion 3501 of the oil passage 35 can be alternately arranged in the circumferential direction. Thereby, compared with the case where the first flow path portion 9501 of the meandering water passage 950 and the first oil passage portion 3501 of the case oil passage 35 are not alternately arranged in the circumferential direction (see FIG. 13), the cooling water and the oil The amount of heat exchange between them can be efficiently increased.

  Thus, according to the stator cooling structure 402 of the present embodiment, the stator core 112 can be efficiently cooled. Therefore, according to the stator cooling structure 402, the oil cooler can be unnecessary even in the motor 10 having a relatively high output.

  In the intersection region P1 where the meandering water channel 950 and the case oil passage 35 intersect, the radial dimension (height) of each of the meandering water channel 950 and the case oil passage 35 is smaller than that of the other regions. The intersection region P1 can be formed without significantly increasing the radial dimensions of the meandering water channel 950 and the case oil channel 35 as a whole compared to other regions. For example, when reducing the radial dimension (height) of each of the meandering water channel 950 and the case oil channel 35 by half, the intersection area P1 can be formed in such a manner that the radial dimension is the same as other areas.

  Further, according to the stator cooling structure 402 according to the present embodiment, the holding ring 60 forming the meandering water channel 950 is in contact with the stator core 112, and therefore, between the cooling water and the stator core 112, the inside of the holding ring 60 in the radial direction is provided. There is only an inner diameter side wall surface portion 651 (see FIGS. 11 and 12). Here, the cooling water is cooled by heat exchange with the outside air (for example, air passing when the vehicle is traveling) by the radiator 92 as described above, and the oil is heat-exchanged with the cooling water by the heat exchange and water cooling unit 50. Since it is cooled, the cooling water is cooler than the oil. Therefore, the stator core 112 can be cooled more efficiently by the cooling water than when another medium or member such as oil is interposed between the cooling water and the stator core 112.

  Further, according to the stator cooling structure 402 according to the present embodiment, by forming the meandering water channel 950, the flow direction of the cooling water can be regulated. For example, the cooling water is linearly cooled from the cooling water inlet 62d to the cooling water outlet 62e. Compared to the case where water flows, the range where significant flow velocity is generated without stagnation or the like (the range where heat exchange is substantially realized) is larger. In addition, in the case of the meandering water channel 950, random flow due to turbulence is likely to occur, and heat diffusion in the cooling water is more likely to occur. This is the same for the case oil passage 35 having the same meandering form. As a result, the heat exchange function and the stator core water cooling function of the heat exchange and water cooling section 50 described above can be enhanced.

  Further, according to the stator cooling structure 402 according to the present embodiment, the cooling water passages (that is, the inlet water passages 951 and the outlet water passages 952) are also formed in the radially extending bottom surface portion 62 of the holding ring 60. Oil stored in the oil storage space of the motor 10 can be cooled more efficiently than when no cooling water passage is formed in the motor 62. That is, by the arrangement of the inlet water channel 951 and the outlet water channel 952 overlapping with the oil storage space as viewed in the X direction, the cooling water in the inlet water channel 951 and the outlet water channel 952 can efficiently cool the oil stored in the oil storage space. In particular, since relatively low-temperature cooling water flows through the inlet water channel 951, the inlet water channel 951 is formed on the bottom portion 62, so that the oil stored in the oil storage space of the motor 10 can be efficiently cooled.

  Further, according to the stator cooling structure 402 of the present embodiment, since the cooling water inlet 62 d and the cooling water outlet 62 e are formed on the bottom surface 62 of the holding ring 60, the cooling water is formed on the cylindrical portion 64 of the holding ring 60. The cooling capacity by the inlet water channel 951 and the outlet water channel 952 can be increased as compared with the case where the inlet portion and / or the cooling water outlet portion is formed. For example, when the cooling water inlet portion is provided in the cylindrical portion 64 of the retaining ring 60, the cooling water in the inlet water passage 951 tends to stay, so that the cooling capacity tends to deteriorate. By forming the cooling water inlet 62d and the cooling water outlet 62e on the bottom surface 62 of the holding ring 60, a cooling water inlet and / or a cooling water outlet is formed on the cylindrical portion 64 of the holding ring 60. It is also possible to minimize the physique in the radial direction as compared with the case where

  Further, according to the stator cooling structure 402 according to the present embodiment, since the first oil passage portion 3501 provided with the oil inlet portion 35a is adjacent to the meandering water passage 950 in the circumferential direction, the oil introduced into the case oil passage 35 is In the first oil passage portion 3501, cooling (heat exchange) can be performed by cooling water in the meandering water passage 950. That is, the oil introduced into the case oil passage 35 can be cooled from an early stage by utilizing heat exchange in the circumferential direction.

  Further, in the above-described embodiment, since the first oil passage portion 3501 connected to the oil inlet portion 35a is disposed in the lowermost region, the cooling in the meandering water passage 950 up to the oil dropping portions 356 and 358 is performed. The time for heat exchange with water can be optimized. That is, since the time required for oil to reach the upper oil dropping portions 356 and 358 is substantially the same in each of the first system and the second system, the cooling time (the time of heat exchange with cooling water) ) Are substantially the same. In this way, the oil can be evenly distributed in the circumferential direction to the oil dropping portions 356 and 358 in each of the first system and the second system. As a result, it is possible to equalize the cooling capacity of the oil introduced from the oil inlet portion 35a and reaching the oil dropping portions 356 and 358.

  As described above, the embodiments have been described in detail. However, the embodiments are not limited to the specific embodiments, and various modifications and changes can be made within the scope described in the claims. It is also possible to combine all or a plurality of the components of the above-described embodiment.

  For example, in the above-described embodiment, the meandering water channel 950 of the cooling water channel 95 is formed so that the cooling water flows in the circumferential direction while flowing back and forth in the X direction, but is not limited thereto. For example, the meandering water channel may be formed so that the cooling water flows in the X direction from the X2 side to the X1 side in the X direction while moving back and forth in the circumferential direction. In this case, also in the meandering oil passage, in a mode having an area adjacent to the meandering waterway in the X direction and an intersecting area, the oil moves in the circumferential direction and moves in the X direction from the X2 side to the X1 side in the X direction. May be formed so as to flow.

  Further, in the above-described embodiment, the radial dimension of each of the cooling water passage 95 and the case oil passage 35 is reduced in the intersection area P1, but is not limited thereto. For example, in the intersection region P1, by forming a concave groove (a concave groove that radially opposes the third ridge portion 643 and the fourth ridge portion 644) in the case 70 in the radial direction outward in the case 70, The reduction amount of the radial dimension of the cooling water passage 95 or the case oil passage 35 may be reduced or set to zero.

  In the above-described embodiment, the cooling water inlet 62d and the cooling water outlet 62e are formed on the bottom surface 62 of the holding ring 60, but the invention is not limited to this. For example, only the cooling water inlet 62d of the cooling water inlet 62d and the cooling water outlet 62e may be formed on the bottom surface 62 of the holding ring 60. In this case, the cooling water outlet 62 e is formed on the cylindrical portion 64 of the holding ring 60 in a manner to be radially connected to the end of the meandering water channel 950 on the X2 side of the first flow path 9501-12. Frequently, outlet channel 952 may be omitted. Similarly, in another modification, a cooling water inlet 62d and a cooling water outlet 62e are formed in the cylindrical portion 64 of the retaining ring 60, and the inlet water channel 951 and the outlet water channel 952 may be omitted.

  Further, the cooling water inlet 62d and the cooling water outlet 62e are provided on the bottom surface 62 of the holding ring 60 so as to be adjacent to each other in the circumferential direction, but are not limited thereto. For example, the cooling water inlet portion 62d and the cooling water outlet portion 62e may be provided on the bottom surface portion 62 of the holding ring 60 at an offset of, for example, 40 degrees or more in the circumferential direction. The cooling water inlet 62d and the cooling water outlet 62e may be provided on the bottom surface 62 of the holding ring 60 so as to be offset in the circumferential direction and the radial direction.

<Appendix>
The following is further disclosed with respect to the above embodiment. Among the effects described below, the effect of each additional mode with respect to one mode is an additional effect resulting from the additional mode.

One form is a cylindrical form along the axial direction (X) of the rotating electric machine (10), and a case (70) supporting a stator core (112) of the rotating electric machine (10);
A meandering cooling water passage (95) and a meandering oil passage (35) are provided between an outer circumferential surface of the stator core (112) and an inner circumferential surface of the case (70);
The cooling water passage (95) and the oil passage (35) have a first region adjacent in the circumferential direction and a second region (P1) intersecting with each other,
At least one of the cooling water passage (95) and the oil passage (35) has a radial dimension of the rotating electric machine (10) smaller in the second region (P1) than in the first region. And a stator cooling structure (402).

  According to this embodiment, between the outer peripheral surface of the stator core (112) and the inner peripheral surface of the case (70), the meandering cooling water passage (95) and the meandering oil passage (35) are adjacent in the circumferential direction. Therefore, the stator core (112) is cooled directly by the cooling water (the cooling water passing through the cooling water passage (95)) (for example, only through the wall surface portion (656) forming the cooling water passage (95)). it can. This allows the stator core (112) to be cooled more efficiently than when another medium (eg, oil) or another member is interposed between the stator core (112) and the cooling water channel forming member (60, 60A). it can. Further, in the second region, the oil in the oil passage (35) can be directly cooled by the cooling water (through only the radial wall portion (652)). Thereby, the efficiency of heat exchange between the oil in the oil passage (35) and the cooling water passing through the cooling water passage (95) can be increased.

  According to this embodiment, at least one of the cooling water passage (95) and the oil passage (35) has a smaller radial dimension in the second region (P1) than in the first region. It is possible to suppress an increase in the physical size of the rotating electric machine (10) in the radial direction due to the intersection of the cooling water passage (95) and the oil passage (35).

In the present embodiment, preferably, the cooling water passage (95) is formed such that the cooling water flows in the circumferential direction of the rotating electric machine (10) while moving back and forth in the axial direction (X),
The oil passage (35) is formed so that oil flows in the circumferential direction while moving back and forth in the axial direction (X),
The cooling water passage (95) and the oil passage (35) have the second region (P1) at an end in the axial direction (X).

  In this case, it is relatively easy to form the meandering cooling water passage (95) and the meandering oil passage (35).

  In the present embodiment, preferably, each of the cooling water passage (95) and the oil passage (35) is such that the dimension in the second area (P1) is substantially half of the dimension in the first area. is there.

  In this case, the radial dimension can be made substantially constant over the entire formation range of the meandering cooling water passage (95) and the meandering oil passage (35). As a result, the size of the rotating electric machine (10) in the radial direction can be reduced as compared with the case where a cylindrical oil passage is formed radially outside the meandering cooling water passage (95).

  In the present embodiment, the cooling water passage (95) and the oil passage (35) may further include a third region adjacent in the axial direction (X).

  In this case, in the third region, the oil in the oil passage (35) can be directly cooled by the cooling water (through only the axial wall portions (653, 654)). Thereby, the efficiency of heat exchange between the oil in the oil passage (35) and the cooling water passing through the cooling water passage (95) can be increased.

  In the present embodiment, preferably, the cooling water passage (95) is adjacent to the oil passage (35) on both sides in the circumferential direction.

  In this case, heat exchange between the cooling water in the cooling water passage (95) and the oil in the oil passage (35) is realized on both sides in the circumferential direction of the cooling water passage (95). Can be increased.

Further, in the present embodiment, the cooling water passage is formed in a cylindrical shape along the axial direction (X), and holds the stator core (112) in such a manner that the inner peripheral surface is in contact with the outer peripheral surface of the stator core (112). Further comprising a member (60);
The cooling water channel (95) is formed inside the cooling water channel forming member (60),
The oil passage (35) may be formed between the radially outer surface of the cooling water passage forming member (60) and the radially inner surface of the case (70).

  In this case, the cooling water channel (95) can be formed using the hollow portion (cavity) of the cooling water channel forming member (60). Further, since grooves (646 to 649) are formed on the radially outer surface of the cooling water channel forming member (60) due to the ridges (641 to 645) related to the cooling water channel (95), such concave grooves are formed. By utilizing the grooves (646 to 649), an oil passage (35) can be formed between the radially outer surface of the cooling channel forming member (60) and the radially inner surface of the case (70).

DESCRIPTION OF SYMBOLS 1 Vehicle drive device 3 Lubrication / cooling system 10 Motor 10a Rotor 10b Stator 12 Reduction mechanism 14 Differential device 22 Lubrication part 23 Cooling part 30 Tank 30a Strainer 31 Oil passage 32 Oil passage 33 Oil passage 34 Oil passage 35 Case oil passage (oil) Road)
35a Oil inlet portion 35b Boundary surface 35c Boundary surface 36 Oil passage 40 Electric oil pump 42 Mechanical oil pump 50 Heat exchange and water cooling unit 60 Retaining ring 62 Bottom part 62a Hole 62b Through hole 62c Oil outlet hole 62d Cooling water inlet part 62e Cooling water outlet 62f Swelling portion 62g Swelling portion 64 Cylindrical portion 70 Case 90 Water pump 92 Radiator 94 Cooling water passage 95 Cooling water passage 110 Coil end 112 Stator core 140 Ring gear 141 Pinion gear 142 Side gear 330 Inlet oil passage 356 Oil dripping portion 358 Oil dripping Part 360 outlet oil passage 400 oil circulation part 401 cooling water circulation part 402 stator cooling structure 640 end part 640a seal groove 641 first ridge 642 second ridge 643 third ridge 644 fourth ridge 645 fifth Ridge 646 concave groove 647 concave groove 648 concave groove 49 concave groove 942 case water path 944 case water path 950 meandering water path 951 inlet water path 952 outlet water path 3501 first oil path section 3502 second oil path section 3561 oil drop hole 3581 oil drop hole 9501 first flow path section 9502 second flow path section 9503 Third flow path BT Bolt I Central axis

Claims (6)

A case supporting the stator core of the rotating electric machine, having a cylindrical shape along the axial direction of the rotating electric machine,
Between the outer peripheral surface of the stator core and the inner peripheral surface of the case, a meandering cooling water passage and a meandering oil passage are included,
The cooling water passage and the oil passage have a first region adjacent in the circumferential direction of the rotating electric machine, and a second region crossing each other,
A stator cooling structure, wherein at least one of the cooling water passage and the oil passage has a smaller dimension in a radial direction of the rotating electric machine in the second region than in the first region. The cooling water passage is formed so that cooling water flows in the circumferential direction of the rotating electric machine while moving back and forth in the axial direction,
The oil passage is formed so that oil flows in the circumferential direction while moving back and forth in the axial direction,
The stator cooling structure according to claim 1, wherein the cooling water passage and the oil passage have the second region at an end in the axial direction.   3. The stator cooling structure according to claim 1, wherein each of the cooling water passage and the oil passage has the dimension in the second region substantially half the dimension in the first region. 4.   The stator cooling structure according to any one of claims 1 to 3, wherein the cooling water passage and the oil passage further include a third region adjacent in the axial direction.   The stator cooling structure according to any one of claims 1 to 4, wherein the cooling water passage is adjacent to the oil passage on both sides in the circumferential direction. A cooling water channel forming member that holds the stator core in a form in which the inner peripheral surface is in contact with the outer peripheral surface of the stator core, which is a cylindrical form along the axial direction,
The cooling water passage is formed inside the cooling water passage forming member,
The oil passage according to any one of claims 1 to 5, wherein the oil passage is formed between the radially outer surface of the cooling water passage forming member and the radially inner surface of the case. The described stator cooling structure.