JP2006271149A - Motor cooling device - Google Patents

Abstract

An object of the present invention is to uniformly cool a motor and to reduce the load on a pump that pumps cooling water by eliminating a difference in level between a cooling water inlet and a cooling water outlet.
A cooling water passage extending in the circumferential direction is formed in a substantially cylindrical main case that accommodates a motor, and both circumferential ends of the cooling water passage are opposed to each other, and one circumferential end portion is provided. In the motor cooling apparatus in which the cooling water inlet portion is provided at the other peripheral end portion and the cooling water outlet portion is provided at the other peripheral end portion, the inlets for reducing the width of the cooling water passage in the respective peripheral end portions in a direction away from each other. A side reduction portion and an outlet side reduction portion are formed, and the inlet side reduction portion and the outlet side reduction portion are arranged side by side in the width direction of the cooling water passage.
[Selection] Figure 1

Description

  The present invention relates to a motor cooling device, and in particular, can uniformly cool a motor, and reduces the load on a pump that pumps cooling water by eliminating the difference in level between the cooling water inlet and the cooling water outlet. The present invention relates to a motor cooling device.

  A motor used as a drive source for a vehicle or the like heats a coil of a stator when energized, and the core of the stator also generates heat due to the influence of magnetic flux. There is a need. In general, a cooling device for preventing a temperature rise of a motor forms a cooling water passage through which cooling water flows in a main case covering the motor, and the cooling water flowing through this cooling water passage absorbs heat generated by the motor and discharges it. This prevents the temperature from rising.

In a conventional motor cooling device, an annular cooling water passage through which cooling water flows is formed in the main case of the motor, a cooling water inlet is provided at the lowest vertical direction of the annular cooling water passage, and the lowest in the vertical direction is provided. Some have a cooling water outlet at the top.
JP-A-8-19218

Further, in the conventional motor cooling device, a double spiral cooling water passage composed of an outward path and an inward path is formed in the outer periphery of the main case of the motor in the axial direction of the main case. There is a cooling water inlet portion and a cooling water outlet portion provided on one side in the direction and provided in communication with the U-turn portion on the other side in the radial direction.
JP-A-9-308183

  By the way, there exist some which are shown in FIGS. 13-15 in the cooling device of the conventional motor. In the figure, 202 is a motor, 204 is a main case, and 206 is a cooling device. The cooling device 206 is formed by forming a cooling water passage 208 extending in the circumferential direction in a substantially cylindrical main case 204 that accommodates the motor 202, and opposing both end portions 210 and 212 in the circumferential direction.

  The cooling water passage 208 is provided with an inlet-side reduced portion 214 formed at one peripheral end 210 and an outlet-side reduced portion 216 formed at the other peripheral end 212. The inlet-side reduced portion 214 and the outlet-side reduced portion 216 are formed so as to reduce as they approach each other at the center in the width direction of the cooling water passage 208. The inlet-side reduced portion 214 and the outlet-side reduced portion 216 are disposed on one side in the horizontal direction (frontward in the drawing) and vertically opposed at the center in the width direction of the cooling water passage 208. .

  The inlet side reducing portion 214 and the outlet side reducing portion 216 are provided with a cooling water inlet portion 218 and a cooling water outlet portion 220, respectively. The cooling water inlet portion 218 and the cooling water outlet portion 220 are arranged side by side at the center in the width direction of the cooling water passage 208 and are oriented in the horizontal direction (forward in the drawing).

  However, in the cooling device 206 of the motor 202, the cooling water inlet portion 218 and the cooling water outlet portion 220 of the cooling water passage 208 are arranged side by side, so that the cooling water inlet portion 218 is arranged as shown in FIG. There is a disadvantage in that a pressure loss due to a height difference occurs between the cooling water outlet 220 and the cooling water outlet 220, and a load on a pump (not shown) for circulating the cooling water is increased.

  In addition, the cooling device 206 of the motor 202 includes an inlet side reduction portion that reduces the two circumferential ends 210 and 212 in the width direction center of the cooling water passage 208 in directions close to each other on the structure of the cooling water passage 208. Since 214 and the outlet side reduced portion 216 are formed, there is a problem of generating a non-cooling region (dead space) 222 in which the cooling water cannot flow as shown by hatching in FIG. It was difficult to uniformly cool the motor, and there was a possibility of adversely affecting the motor performance.

  Further, the cooling device 206 of the motor 202 is configured such that when a component such as a side case (not shown) is attached to one side in the axial direction of the main case 204 that houses the motor 202, as shown in FIG. On the other hand, the boss 226 for the mounting screw hole 224 must be formed so as to protrude from the outer periphery of the main case 204, resulting in an inconvenience of increasing the weight and size of the main case 204.

  In the present invention, a cooling water passage extending in the circumferential direction is formed in a substantially cylindrical main case that houses a motor, and both peripheral ends of the cooling water passage are opposed to each other, and a cooling water inlet is provided at one peripheral end. And a cooling device for a motor provided with a cooling water outlet at the other peripheral end, and an inlet side reducing portion for reducing the width of the cooling water passage in the direction away from each other at each of the peripheral ends. An outlet-side reduced portion is formed, and the inlet-side reduced portion and the outlet-side reduced portion are arranged side by side in the width direction of the cooling water passage.

  In the motor cooling device according to the present invention, an inlet-side reduced portion and an outlet-side reduced portion that reduce the width of the cooling water passage in directions away from each other are formed at both ends of the cooling water passage, respectively. And the outlet side reduced portion are arranged in the width direction of the cooling water passage so that the cooling water formed between the circumferential ends of the cooling water passage cannot flow. The area can be reduced, and the motor can be cooled uniformly. Further, the cooling water inlet and the cooling water outlet can be provided at substantially the same position in the circumferential direction, and the load on the pump for pumping the cooling water can be reduced without the difference in height between the two.

The motor cooling device according to the present invention includes an inlet side reduced portion and an outlet side reduced portion formed in each of the peripheral end portions of the cooling water passage, which are arranged side by side in the width direction of the cooling water passage. It is possible to reduce the area of the non-cooling region where the cooling water formed between the circumferential ends of the passage cannot flow, and to cool the main case uniformly. Further, the cooling water inlet and the cooling water outlet can be provided at substantially the same position in the circumferential direction, and the load on the pump for pumping the cooling water can be reduced without the difference in height between the two.
Embodiments of the present invention will be described below with reference to the drawings.

  1 to 10 show an embodiment of the present invention. In FIG. 5, 2 is a hybrid drive device mounted on a vehicle such as a hybrid electric vehicle (not shown), 4 is an engine, 6 is a gear portion, and 8 is a motor portion. The engine 4 is provided with a flywheel 14 attached to the end of a crankshaft 12 pivotally supported on the cylinder block 10, and a damper 16 for adjusting torque fluctuation is attached to the flywheel 14.

  The gear portion 6 is provided with a gear case 18. The gear case 18 includes first and second cases 20 and 22, has first and second case wall portions 24 and 26, and the first and second cases 20 and 22 are joined by mounting bolts (not shown). . The gear portion 6 joins the first case 20 to the cylinder block 10 with mounting bolts (not shown).

  The motor unit 8 is provided with a motor case 28. The motor case 28 includes a substantially cylindrical main case 30, a side plate 32 joined to one side in the axial direction of the main case 30, and a side case 34 joined to the other side in the axial direction of the main case 30. 30 has a main case wall 36, and a side plate 32 and a side case 34 are joined to the main case 30 by mounting bolts 38 and 40. In the motor unit 8, the main case 30 is joined to the first case 20 via the side plate 32 by means of mounting bolts 42.

  The hybrid drive device 2 includes an input shaft 44. One end of the input shaft 44 is pivotally supported at the center of the flywheel 14 at the end of the crankshaft 12 and is connected to the damper 16, the vicinity of the one end is pivotally supported by the first case wall 24, and the intermediate portion is the second case. The wall 26 and the side plate 32 are inserted, and the other end is pivotally supported by the side case 34. The input shaft 44 is allowed to rotate only in the forward rotation direction of the engine 4 by a one-way clutch 46 provided between the input shaft 44 and the first case wall portion 24.

  The gear portion 6 is provided with an output gear 48 that is an output member for outputting the power of the engine 4 to drive wheels (not shown). The output gear 48 is pivotally supported by the first case wall portion 24 and meshed with the intermediate gear 50. The intermediate gear 50 is attached to an intermediate shaft 52 that is pivotally supported by the first and second case wall portions 24 and 26. A final reduction drive gear 54 is provided on the intermediate shaft 52, and a final reduction driven gear 56 is engaged with the intermediate shaft 52. The final reduction driven gear 56 is attached to a differential 58 that is pivotally supported by the first and second case wall portions 24 and 26. The differential 58 communicates with one end of each of the left and right drive axles 60 and 62. Drive wheels (not shown) are provided on the other end sides of the drive axles 60 and 62.

  The input shaft 44 is provided with a power distribution mechanism 64 adjacent to the output gear 48. The power distribution mechanism 64 includes first and second planetary gear trains 66 and 68.

  The first planetary gear train 66 is disposed on the engine 4 side, and is engaged with the first sun gear 70 supported by the input shaft 44 and the first pinion gear 72 that is engaged with the first sun gear 70 and supported by the input shaft 44. And a first ring gear 74 that meshes with the first pinion gear 72 and is connected to the output gear 48.

  The second planetary gear train 68 is disposed on the motor unit 8 side, and is engaged with the second sun gear 76 and the second sun gear 76 connected to the first sun gear 70, and the second sun gear 76 is supported by the input shaft 44. It consists of a pinion gear 78 and a second ring gear 80 that meshes with the second pinion gear 78 and is connected to a second rotor shaft 100 of a second motor generator 84 described later.

  The motor unit 8 includes a first motor generator 82 that is a motor mainly used for power generation, and a second motor generator 84 that is a motor mainly used for driving.

  The first motor generator 82 is provided between the main case wall 36 and the side case 34 and includes a first motor stator 86 and a first motor rotor 88. The first motor stator 86 is attached to the inner periphery of the main case 30. The first motor rotor 88 is attached to a first rotor shaft 90 that is pivotally supported by the main case wall 36 and the side case 34. The first rotor shaft 90 is coupled to the first sun gear 70 so as to rotate in the same direction by the extension cylinder portion 92. The first motor generator 82 includes a first rotation sensor (resolver) 94 that detects the angular position of the first motor rotor 88.

  The second motor generator 84 is disposed between the side plate 32 and the main case wall 36 and includes a second motor stator 96 and a second motor rotor 98. The second motor stator 96 is attached to the inner periphery of the main case 30. The second motor rotor 98 is attached to the second rotor shaft 100 that is pivotally supported by the main case wall 36. The second rotor shaft 100 is provided with the second ring gear 80. The second motor generator 84 includes a second rotation sensor (resolver) 102 that detects the angular position of the second motor rotor 98.

  An oil pump 104 is provided on the side case 34 that pivotally supports the other end of the input shaft 44. As shown in FIGS. 6 to 8, the oil pump 104 is provided with a pump housing 106 in the side case 34, and a pump rotor 110 rotated by the input shaft 44 is rotatably provided in a pump chamber 108 in the pump housing 106. A pump plate 112 is attached to the side case 34 so as to cover the pump chamber 108 and the pump rotor 110, and a suction hole 114 and a discharge hole 116 communicating with the pump chamber 108 are provided.

  A suction passage 120 provided in a passage forming portion 118 of the pump plate 112 communicates with the suction hole 114. The suction passage 120 has a lubricating oil passage 122 for oil return that communicates between the second case 22 of the gear case 18 joined to one side in the axial direction of the main case 30 and the side case 34 joined to the other side. Communicate. The lubricating oil passage 122 for returning oil returns the lubricating oil after lubricating the output gear 48 and the first and second planetary gear trains 66 and 68 to the oil pump 104.

  The discharge hole 116 communicates with a lubricating oil passage 124 for oil supply provided in the input shaft 44. The lubricating oil passage 124 for supplying oil extends to the second case 22 of the gear case 18 joined to one side in the axial direction of the main case 30, and the output gear 48 and the first and second planetary gear trains 66 and 68 are connected to the gear case 18. Lubricate.

  The hybrid drive device 2 includes a cooling device 126 that cools the first motor generator 82 and the second motor generator 84 that are motors. As shown in FIG. 4, the cooling device 126 is positioned on the lower side in the vertical direction of the substantially cylindrical main case 30 that houses the first motor generator 82 and the second motor generator 84, and protrudes downward in the axial direction. An extended bulge 128 is provided. In the bulging portion 128, a cooling water inlet pipe 130 and a cooling water outlet pipe 132 that are parallel to each other are protruded at the same height on one side in the horizontal direction (frontward in the drawing). Provided.

  As shown in FIGS. 1 to 3, the cooling device 126 forms a cooling water passage 134 extending in the circumferential direction in a substantially cylindrical main case 30 that houses the first motor generator 82 and the second motor generator 84 that are motors. In addition, both circumferential end portions 136 and 138 in the circumferential direction of the cooling water passage 134 are provided to face each other.

  The cooling water passage 134 is provided with an inlet side reduced portion 140 formed at one peripheral end portion 136 and an outlet side reduced portion 142 formed at the other peripheral end portion 138. The inlet-side reduced portion 140 and the outlet-side reduced portion 142 are arranged side by side in the width direction of the cooling water passage 134 by reducing the width of the cooling water passage 134 in a direction away from each other. The inlet-side reduced portion 140 and the outlet-side reduced portion 142 are provided so as to be positioned on the lower side in the vertical direction of the main case 30, and are offset toward each other in the width direction of the cooling water passage 134 so that the cross section gradually decreases. Is formed.

  The bulging portion 128 provided on the lower side of the main case 30 is provided with an inlet-side water reservoir 144 protruding below the outer peripheral surface of the inlet-side reducing portion 140, and the outlet below the outer peripheral surface of the outlet-side reducing portion 142. A side water reservoir 146 is provided so as to protrude. The inlet-side water reservoir 144 and the outlet-side water reservoir 146 are arranged side by side in the axial direction in the bulging portion 128 on the lower side in the vertical direction of the main case 30.

  The cooling water inlet pipe 130 protruding from the bulging portion 128 is provided with a cooling water inlet portion 148 communicating with the inlet side water reservoir 144. Further, the cooling water outlet pipe 132 protruding from the bulging portion 128 is provided with a cooling water outlet portion 150 that communicates with the outlet side water reservoir 146. The cooling water inlet portion 148 and the cooling water outlet portion 150 are oriented at the same height from the inlet side water reservoir portion 144 and the outlet side water reservoir portion 146 to one side in the horizontal direction (frontward in the drawing) and parallel to each other. It is provided. The cooling water inlet 148 and the cooling water outlet 150 are connected to a discharge side and a suction side of a pump (not shown) to supply and discharge the cooling water.

  Further, as shown in FIGS. 3 and 4, the bulging portion 128 includes a main case along the other horizontal side (rear in the drawing) of the inlet side water reservoir 144 and the outlet side water reservoir 146, respectively. The oil return lubricating oil passage 122 that communicates between the gear case 18 joined to one axial side of the 30 and the side case 34 joined to the other side is provided.

  Next, the operation of this embodiment will be described.

  As shown in FIG. 5, the hybrid drive device 2 includes an engine 4 that generates power by burning fuel, a first motor generator 82 that is mainly used for power generation, a second motor generator 84 that is mainly used for driving, and a first motor generator 84. The engine 4 and the second motor generator are mounted on a vehicle such as a hybrid electric vehicle by combining a power distribution mechanism 64 composed of the second planetary gear trains 66 and 68 and an output gear 48 that outputs power to drive wheels. The first motor generator 82 generates electricity while traveling with one or a combination of both.

  The first and second motor generators 82 and 84 that are the motors of the hybrid drive device 2 are rotated by a rotational force from drive wheels (not shown) or a current supplied from a control device, and generate electricity and drive force. At this time, in the first and second motor generators 82 and 84, the coils generate heat when energized, and also generate heat due to the influence of magnetic flux.

  As shown in FIGS. 1 to 3, a cooling water passage 134 of the cooling device 126 is provided in the main case 30 of the motor unit 8 that houses the first and second motor generators 82 and 84. The cooling device 126 circulates cooling water pumped by a pump (not shown) through the cooling water passage 134 of the main case 30.

  The heat generated by the first and second motor generators 82 and 84 flows into the cooling water inlet 148 provided at the lower portion of the main case 30 and is absorbed by the cooling water flowing through the arc-shaped cooling water passage 134. 30 is discharged together with the cooling water from the cooling water outlet 150 provided at the lower part of 30. Thereby, the first and second motor generators 82 and 84 can prevent the temperature from rising.

  In this way, the cooling device 126 includes an inlet side reduction portion that reduces the width of the cooling water passage 134 in the direction away from each other at both peripheral ends 136 and 138 of the cooling water passage 134 as shown in FIGS. 140 and the outlet-side reduced portion 142 are formed, and the inlet-side reduced portion 140 and the outlet-side reduced portion 142 are arranged side by side in the width direction of the cooling water passage 134.

  Thereby, this cooling device 126 reduces the area of the non-cooling region 152 (dead space) formed between the circumferential ends 136 and 138 in the circumferential direction of the cooling water passage 134 where the cooling water cannot flow. The main case 30 that houses the first and second motor generators 82 and 84 can be uniformly cooled. In addition, the cooling device 126 can provide the cooling water inlet portion 148 and the cooling water outlet portion 150 at substantially the same height in the circumferential direction (dashed line), and eliminates the difference in height between the two. The load on the pump to be pumped can be reduced.

  Further, the cooling device 126 is provided with an inlet-side water reservoir 144 communicating with the cooling water inlet 148 protruding from the outer peripheral surface of the inlet-side reducing portion 140 of the cooling water passage 134, and on the outer peripheral surface of the outlet-side reducing portion 142. An outlet-side water reservoir 146 communicating with the cooling water outlet 150 is provided so as to protrude, and the inlet-side water reservoir 144 and the outlet-side water reservoir 146 are arranged side by side in the axial direction of the main case 30. And the outlet-side water reservoir 146 can be concentrated on the outer periphery of the main case 30 and the cooling device 126 including the inlet-side water reservoir 144 and the outlet-side water reservoir 146 can be downsized. .

  Further, the cooling device 126 is provided with the inlet-side water reservoir 144 and the outlet-side water reservoir 146 positioned on the lower side in the vertical direction of the main case 30, and along the inlet-side water reservoir 144 and the outlet-side water reservoir 146. By providing the lubricating oil passage 122 that communicates between the gear case 18 joined to one side in the axial direction of the main case 30 and the side case 34 joined to the other side, the inlet-side water reservoir 144 and the outlet-side water reservoir are provided. The portion 146 and the lubricating oil passage 122 can be centrally arranged on the outer peripheral portion of the main case 30, and the cooling device 126 including the lubricating oil passage 122 can be downsized and the lubricating oil can be cooled. be able to.

  The present invention is not limited to the above-described embodiments, and various application modifications can be made.

  For example, FIGS. 9 and 10 show a first modification. As shown in FIG. 9, the cooling device 126 is provided with mounting screw hole relief portions 154 and 156 formed at required positions at both ends in the width direction of the cooling water passage 134, and the cooling water passage 134 in the circumferential direction is provided. The motor cable outlet relief portions 158 and 160 are formed and formed at the required positions.

  As a result, the hybrid drive device 2 provided with the cooling device 126 has the side plate 32 and the side case 34 provided at required positions on both ends in the axial direction of the main case 30 provided with the cooling water passage 134, as shown in FIG. The mounting screw holes 162 and 164 of the mounting bolts 38 and 40 to be connected can be formed, and it is not necessary to form a boss portion for the mounting screw hole on the outer periphery of the main case 30, and the main case 30 is reduced in size and weight. Can be fulfilled.

  Further, as shown in FIG. 4, the hybrid drive device 2 provided with the cooling device 126 is connected to the first and second motor generators 82 and 84 at a required position in the circumferential direction of the main case 30 provided with the cooling water passage 134. An extraction hole 166 of a motor cable (not shown) to be connected can be formed, and the degree of freedom in layout can be improved.

  FIG. 11 shows a second modification. The cooling device 126 forms a bulging portion 168 that protrudes toward the outlet-side water reservoir 146 in the inlet-side water reservoir 144 with respect to the outlet-side water reservoir 146 positioned on the lower side in the vertical direction of the main case 30. It is a thing.

  Thus, the cooling device 126 can arrange the inlet-side water reservoir 144, the outlet-side water reservoir 146, and the lubricating oil passage 122 in a concentrated manner on the outer peripheral portion of the main case 30, and includes the lubricating oil passage 122. The cooling device 126 can be reduced in size, and the volume of the inlet-side water reservoir 144 through which the cold cooling water before being warmed can be expanded by the bulging portion 168, and this volume is increased. The lubricating oil in the lubricating oil passage 122 disposed along the portion 144 can be cooled more satisfactorily.

  FIG. 12 shows a third modification. The cooling device 126 is provided with a cooling water inlet 148 that communicates with an inlet-side water reservoir 144 positioned on the lower side in the vertical direction of the main case 30 so as to open toward the one axial side of the main case 30. A cooling water outlet pipe 132 is provided in the outlet side water reservoir 146 located on the lower side in the vertical direction of the main case 30 so as to open toward the other side in the axial direction of the main case 30.

  As a result, the cooling device 126 includes the inlet-side water reservoir 144 and the outlet-side water reservoir 146 so that the cooling water inlet 148 and the cooling water outlet 150 are aligned with the flow direction of the cooling water in the cooling water passage 134. The flow resistance can be reduced by eliminating the reversal of the flow direction of the cooling water by the cooling water outlet portion 150 on the outlet side of the cooling water passage 134, and the load of the pump for pumping the cooling water can be reduced. Can be reduced.

  According to the motor cooling device of the present invention, the area of the non-cooling region where the cooling water formed between the circumferential ends of the cooling water passage cannot flow can be reduced, and the motor can be cooled uniformly. It is possible to reduce the load on the pump that pumps the cooling water by eliminating the difference in height between the cooling water inlet and the cooling water outlet, and can be used in various machines that use the motor as a prime mover. Can be applied.

It is a perspective view of the cooling water channel | path of the cooling device which shows an Example. It is a bottom view by the arrow II of FIG. 1 which shows an Example. It is a side view of the cooling water path which shows an Example. It is a perspective view of the main case which shows an Example. It is sectional drawing of the hybrid drive device provided with the cooling device which shows an Example. It is a perspective view of the motor case which shows an Example. It is a side view of the motor case which shows an Example. It is sectional drawing by the arrow VIII-VIII line of FIG. 7 which shows an Example. It is a perspective view of the cooling water passage which shows the 1st modification. It is a perspective view of the main case which shows a 1st modification. It is a bottom view of a cooling water passage showing a second modification. It is a bottom view of a cooling water passage showing a third modification. It is a perspective view of the main case which shows a prior art example. It is a perspective view of the cooling water path which shows a prior art example. It is the front of the cooling water channel | path which shows a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Hybrid drive device 4 Engine 6 Gear part 8 Motor part 18 Gear case 20 1st case 22 2nd case 28 Motor case 30 Main case 32 Side plate 34 Side case 44 Input shaft 48 Output gear 50 Intermediate gear 58 Differential machine 64 Power distribution mechanism 66 First planetary gear train 68 Second planetary gear train 82 First motor generator 84 Second motor generator 104 Oil pump 122 Lubricating oil passage 126 Cooling device 128 Swelling portion 130 Cooling water inlet pipe 132 Cooling water outlet pipe 134 Cooling water passage 134 136 and 138 peripheral edge part 140 inlet side reduction part 142 outlet side reduction part 144 inlet side water reservoir part 146 outlet side water reservoir part 148 cooling water inlet part 150 cooling water outlet part

Claims (3)

  A cooling water passage extending in the circumferential direction is formed in a substantially cylindrical main case that accommodates the motor, and both peripheral ends of the cooling water passage are provided facing each other, and a cooling water inlet is provided at one peripheral end. In the motor cooling apparatus having the cooling water outlet portion at the other peripheral end portion, the inlet side reducing portion and the outlet side reducing portion that reduce the width of the cooling water passage in the direction away from each other at each of the peripheral end portions. And the inlet-side reduced portion and the outlet-side reduced portion are arranged side by side in the width direction of the cooling water passage.   An inlet-side water reservoir that communicates with the cooling water inlet is provided on the outer peripheral surface of the inlet-side reduced portion, and an outlet-side water reservoir that communicates with the cooling water outlet is provided on the outer peripheral surface of the outlet-side reduced portion. 2. The motor cooling device according to claim 1, wherein the motor-side cooling device according to claim 1, wherein the motor-cooling device is provided so as to protrude and the inlet-side water reservoir and the outlet-side water reservoir are arranged in the axial direction of the main case.   The inlet-side water reservoir and the outlet-side water reservoir are provided so as to be positioned on the lower side in the vertical direction of the main case, and along the inlet-side water reservoir and the outlet-side water reservoir, the axial direction of the main case 3. The motor cooling device according to claim 2, further comprising a lubricating oil passage that communicates between a gear case joined to one side and a side case joined to the other side.

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