Vehicle drive systems

Abstract

To provide a vehicle drive system that can reduce the overall size by suppressing the protrusion of the oil cooler from the case, while also improving the cooling performance of the oil cooler. [Solution] An oil passage for cooling the power generation motor 21 and the drive motor 23 is formed in the case 3A. The drive motor 23 is positioned behind the power generation motor 21, and the differential gear 16 is positioned below the drive motor 23. An oil cooler 7 for cooling the oil is positioned on the outer surface of the case 3A, below the power generation motor 21 and in front of the differential gear 16.

Description

Technical Field

[0001] The present invention relates to a vehicle drive device.

Background Art

[0002] The vehicle drive device described in Patent Document 1 aims to suppress an increase in cost, connect an oil cooler and an oil passage, and achieve miniaturization of a case body. It has a transaxle housing that houses an electric motor, an oil passage for oil that cools the electric motor, and an oil cooler disposed on a side portion of the transaxle housing. At least a part of the oil passage extends from below the electric motor upward, and a part of the oil passage that extends upward has an oil passage structure that the oil cooler also serves as.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the device described in Patent Document 1, since the oil passage is formed such that all the oil pumped from the oil pump passes through the oil cooler and then is supplied to the electric motor, the oil passage becomes long and complex. If an attempt is made to shorten the oil passage, the mounting position of the oil cooler is restricted. Therefore, when the oil cooler is disposed so as to protrude from the transaxle housing, there is a problem that the overall size including the oil cooler becomes large.

[0005] Therefore, an object of the present invention is to provide a vehicle drive device that can reduce the overall size by suppressing the protrusion of the oil cooler from the case and can improve the cooling performance of the oil cooler.

Means for Solving the Problems

[0006] To solve the above problems, the present invention provides a vehicle drive system comprising a case housing an input shaft to which power is input from an engine, a power generator motor that generates electricity using the power input to the input shaft, a drive motor that operates using the electricity generated by the power generator motor, and a differential that distributes the power generated by the drive motor to the left and right drive wheels, wherein oil passages for cooling the power generator motor and the drive motor are formed in the case, the drive motor is positioned behind the power generator motor, the differential is positioned below the drive motor, and an oil cooler for cooling the oil is positioned on the outer surface of the case, below the power generator motor and in front of the differential. [Effects of the Invention]

[0007] Thus, according to the present invention, it is possible to provide a vehicle drive system that can reduce the overall size by suppressing the protrusion of the oil cooler from the case, and can also improve the cooling performance of the oil cooler. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a left side view of a vehicle drive system according to one embodiment of the present invention. [Figure 2] Figure 2 is a cross-sectional view of the vehicle drive system in Figure 1, taken along the II-II line. [Figure 3] Figure 3 is a right side view of the left case of a vehicle drive device according to one embodiment of the present invention. [Figure 4] Figure 4 is a right side view of the left case showing the oil passage of the left case of a vehicle drive device according to one embodiment of the present invention. [Figure 5] Figure 5 is a diagram showing the configuration of the oil passages in a vehicle drive system according to one embodiment of the present invention. [Modes for carrying out the invention]

[0009] A vehicle drive system according to one embodiment of the present invention comprises a case housing an input shaft to which power is input from an engine, a generator motor that generates electricity using the power input to the input shaft, a drive motor that operates using the electricity generated by the generator motor, and a differential that distributes the power generated by the drive motor to the left and right drive wheels. The vehicle drive system is characterized in that oil passages for cooling oil for the generator motor and the drive motor are formed in the case, the drive motor is positioned behind the generator motor, the differential is positioned below the drive motor, and an oil cooler for cooling the oil is positioned on the outer surface of the case, below the generator motor and in front of the differential. As a result, the vehicle drive system according to one embodiment of the present invention can reduce the overall size by suppressing the protrusion of the oil cooler from the case, and can also improve the cooling performance of the oil cooler. [Examples]

[0010] Hereinafter, a vehicle drive system according to one embodiment of the present invention will be described with reference to the drawings. Figures 1 to 5 are diagrams showing a vehicle drive system according to one embodiment of the present invention.

[0011] In Figures 1 to 5, the vertical, longitudinal, left-right, and right-right directions are based on the vehicle's drive system as it is positioned on the vehicle. The longitudinal direction of the vehicle is defined as the longitudinal direction, the left-right direction (vehicle width direction) as the left-right direction, and the vertical direction (vehicle height direction) as the vertical direction.

[0012] As shown in Figures 1 and 2, the engine compartment (not shown) at the front of the vehicle 1 contains an internal combustion engine 2 and a drive unit 3 connected to the engine 2. The engine 2 is positioned transversely in the engine compartment so that the cylinder row direction is in the direction of the vehicle width. The drive unit 3 is connected to the left end of the engine 2. In this embodiment, the drive unit 3 constitutes a vehicle drive unit.

[0013] The drive unit 3 includes a case 3A as a housing. The case 3A houses an input shaft 10 to which power is input from the engine 2, a generator motor 21 that generates electricity using the power input to the input shaft 10, a drive motor 23 that operates using the electricity generated by the generator motor 21, and a differential 16 that distributes the power generated by the drive motor 23 to the left and right drive wheels (not shown) via left and right drive shafts 15. Thus, the vehicle 1 consists of a so-called two-motor series hybrid vehicle.

[0014] Case 3A has a motor chamber 22 for housing the power generation motor 21 and a motor chamber 24 for housing the drive motor 23. Case 3A consists of a cylindrical right case 4 connected to the left end of the engine 2, a cylindrical left case 5 connected to the left end of the right case 4, and a cover member 6 connected to the left end of the left case 5.

[0015] As shown in Figure 2, a damper 8 connecting the crankshaft 2A and the input shaft 10 is housed between the light case 4 and the engine 2. An input gear 10A is fixed to the input shaft 10. The light case 4 holds a bearing 4B that supports the input shaft 10 near the right side of the input gear 10A.

[0016] The light case 4 has a vertically extending, wall-shaped partition 4A to the left of the damper 8. The partition 4A divides the interior of the light case 4 into a space on the engine 2 side and a space on the side farther from the engine 2. The bearing 4B is held in place by the partition 4A.

[0017] As shown in Figure 2, a vertical wall portion 5A extending in the vertical direction is provided near the right end of the left case 5. The vertical wall portion 5A extends in the vertical direction on a plane perpendicular to the input shaft 10. The space between the partition wall 4A and the vertical wall portion 5A is the space in which the power transmission mechanism is arranged, and this power transmission space houses the drive reduction gears (gears 12A, 13A, 13B, and ring gear 14) and differential gear 16, which will be described later. The upper part of the vertical wall portion 5A is partition wall portion 5A1, which extends in the vertical direction to divide the inside of the case 3A into the space on the engine 2 side and the space on the cover member 6 side. This space on the cover member 6 side is a motor room 22 that houses the power generation motor 21 and a motor room 24 that houses the drive motor 23. In other words, the power generation motor 21 and the drive motor 23 are located on the upper left side of the vertical wall section 5A, and the power generation motor 21 and the drive motor 23 are mounted on the left side of the partition wall section 5A1 of the vertical wall section 5A. On the right side of the partition wall section 5A1 of the vertical wall section 5A, a bearing 5B is located near the left side of the input gear 10A, supporting the input shaft 10. The outer ring of the bearing 5B is fitted into a hole in the housing 5C and held in place. The housing 5C that holds the bearing 5B is fixed to the right side of the partition wall section 5A1 of the vertical wall section 5A by bolts or the like. In other words, the vertical wall section 5A supports the input shaft 10 via the bearing 5B. The lower part of the vertical wall section 5A is an outer wall section 5A2 that separates the inside and outside of the case 3A, and extends vertically to separate the inside and outside of the case 3A. The left side of the outer wall section 5A2 at the bottom of the vertical wall section 5A is exposed to the outside.

[0018] As shown in FIGS. 1 and 2, the portions forming the motor chambers 22 and 24 in the case 3A bulge to the left of the vertical wall portion 5A. The motor chambers 22 and 24 are cylindrical spaces formed in the left case 5. The left ends of the motor chambers 22 and 24 are closed by the cover member 6. Thus, since the case 3A bulges to the left of the vertical wall portion 5A at the portions forming the motor chambers 22 and 24 to form a bulging portion, there is a space below this bulging portion (below the power generation motor 21 and the drive motor 23), and the outer surface on the left of the outer wall portion 5A2 constituting the lower part of the vertical wall portion 5A faces this space. That is, the outer surface of the outer wall portion 5A2 of the vertical wall portion 5A faces the space below the bulging portion. In this embodiment, an oil cooler 7 described later is disposed in this space, and the oil cooler 7 is attached to the outer surface of the outer wall portion 5A2 at the lower part of the vertical wall portion 5A.

[0019] As shown in FIG. 3, in the left case 5 of the drive device 3, an input shaft 10, a motor shaft 11 which is the rotation shaft of the power generation motor 21, a motor shaft 12 which is the rotation shaft of the drive motor 23, an intermediate shaft 13, and a rotation axis 15 of the differential device 16 are provided parallel to each other.

[0020] The input shaft 10 is connected to the crankshaft 2A of the engine 2 via a damper 8 (see FIG. 2). A gear 11A is provided on the motor shaft 11 of the power generation motor 21, and this gear 11A meshes with an input gear 10A. The rotation transmitted from the engine 2 to the input shaft 10 is shifted (increased in speed in this embodiment) by the meshing of the input gear 10A and the gear 11A and transmitted to the power generation motor 21.

[0021] A gear 12A is provided on the motor shaft 12 of the drive motor 23. On the intermediate shaft 13, a large-diameter gear 13A meshing with the gear 12A and a small-diameter gear 13B meshing with the ring gear 14 of the differential device 16 are provided. The rotation of the drive motor 23 is transmitted to the ring gear 14 from the gear 13B after being speeded up (decelerated in this embodiment) by the meshing of the gear 12A and the gear 13A. Each shaft is arranged vertically one above the other in the order of the motor shaft 12, the intermediate shaft 13, and the rotation axis 15 of the differential device 16 from above at the rear part of the left case 5.

[0022] The differential device 16 including the input gear 10A, the gears 11A, 12A, 13A, 13B, and the ring gear 14 is arranged in a space sandwiched between the partition wall 4A of the right case 4 and the vertical wall portion 5A of the left case 5. An oil storage chamber 25 for storing oil is provided at the bottom of this space. The oil functions as lubricating oil for lubricating lubrication targets including the power generation motor 21 and the drive motor 23, and cooling oil for cooling the lubrication targets.

[0023] The differential device 16 has a ring gear 14, a pinion shaft (not shown), a pair of pinion gears (not shown) rotatably supported on the pinion shaft, and a pair of side gears (not shown) meshing with the pinion gears. The side gears are respectively connected to the left and right drive shafts (not shown).

[0024] The ring gear 14 of the differential device 16 meshes with the gear 13B on the intermediate shaft 13. The differential device 16 transmits the rotation transmitted from the gear 13B to the ring gear 14 to the left and right drive wheels via the left and right drive shafts (not shown) while allowing the differential of the left and right drive wheels (not shown).

[0025] As shown in FIGS. 2 and 4, an oil pump 30 is provided coaxially with the input shaft 10 on the engine 2 side surface of the partition wall portion 5A1 of the vertical wall portion 5A and a small-diameter gear 13B meshing with the ring gear 14 of the differential device 16 are provided. The oil pump 30 is arranged coaxially with the input shaft 10 from the engine 2 and is driven and rotated by the driving force of the engine 2. The oil pump 30 is a trochoid pump that sucks in from the lower side and discharges upward.

[0026] The oil pump 30 is housed in a recess formed on the engine 2 side of the partition wall portion 5A1 of the vertical wall portion 5A, and is closed by a housing 5C that holds the bearing 5B being attached from the engine 2 side. The housing 5C has a through hole through which a drive shaft that rotates the oil pump 30 passes, and is provided coaxially with the input shaft 10. The drive shaft passes through this through hole and connects the input shaft 10 and the inner rotor of the trochoid pump (oil pump 30), and the oil pump 30 is rotated by the rotation of the input shaft 10. The oil pump 30 draws up oil stored in the oil storage chamber 25 from the suction oil passage 31 and sends it to the discharge oil passage 32, thereby pressurizing and supplying it to the object to be lubricated. The rotation direction of the trochoid pump (oil pump 30) is clockwise in Figure 4. The volume chamber between the outer rotor and the inner rotor expands as it moves from the bottom to the rear in Figure 4 due to rotation, drawing oil from the suction oil passage 31, and similarly contracts as it moves from the rear to the top in Figure 4, discharging oil into the discharge oil passage 32. The recess in the vertical wall section 5A that houses the oil pump 30 communicates with the suction oil passage 31 via the suction port and with the discharge oil passage 32 via the discharge port. A strainer 26 for filtering the oil is attached to the oil storage chamber 25 side of the lower outer wall section 5A2 of the vertical wall section 5A. The strainer 26 is immersed in the oil accumulated in the oil storage chamber 25. The internal passage of the strainer 26 communicates with the lower end of the suction oil passage 31, and the oil pump 30 draws up the filtered oil from the internal passage of the strainer 26. In other words, the strainer 26 is attached to the lower part of the vertical wall 5A, on the inner surface side of the case 3A of the vertical wall 5A, to which the oil cooler 7, described later, is attached later. The strainer 26 communicates with the lower end of the suction oil passage 31 and is fastened and fixed to the vertical wall 5A so as to press the plate member 27, which constitutes the suction oil passage 31, against the vertical wall 5A.

[0027] As shown in Figures 1 and 2, an oil cooler 7 for cooling oil is provided on the lower outer wall portion 5A2 of the vertical wall portion 5A on the left outer surface of case 3A (left case 5). The oil cooler 7 is positioned below the bulging portions of the motor chambers 22 and 24, and higher than the lower end of the left case 5. The oil cooler 7 is fixed to the outer wall portion 5A2 of the vertical wall portion 5A in a position that is aligned with the surface of the outer wall portion 5A2 of the vertical wall portion 5A. On the side of the oil cooler 7 facing the vertical wall portion 5A, there is an oil inlet through which oil flows in and an oil outlet through which oil that has passed through the oil cooler 7 flows out. The oil inlet communicates with a communication hole 33A, which is an oil passage formed in the vertical wall portion 5A, and the oil outlet communicates with a communication hole 31A, which is an oil passage formed in the vertical wall portion 5A. In other words, the oil cooler 7 is mounted on the outer surface of the case 3A, specifically on the outer surface of the vertical wall portion 5A. It communicates with the cooler inlet oil passage 33 (described later) via a communication hole 33A, allowing oil to flow in from the cooler inlet oil passage 33, and communicates with the suction oil passage 31 via a communication hole 31A, allowing oil to flow out into the suction oil passage 31. These connections are achieved by fixing the oil cooler 7 to the outer wall portion 5A2 of the vertical wall portion 5A, and each connection part, including the tightening direction for fixing, is configured to be parallel. More specifically, the fixing and communication of the oil cooler 7 are achieved by having each connection part, including the tightening direction for fixing, extend in a direction perpendicular to the vertical wall portion 5A. On the left outer surface of the oil cooler 7, there is an inlet pipe 7A into which coolant enters from a radiator (not shown), and an outlet pipe 7B that sends coolant to the radiator, cooling the oil through heat exchange with the coolant. Since the inlet pipe 7A and outlet pipe 7B are provided on the side opposite to the vertical wall section 5A, the piping can be easily routed.

[0028] As shown in Figures 2, 3, and 4, the right side of the vertical wall portion 5A is formed with a suction oil passage 31 that communicates with the strainer 26 and the oil pump 30, a discharge oil passage 32 that receives the oil discharged by the oil pump 30 and flows it toward the object to be lubricated, and a cooler inlet oil passage 33 that branches off from the discharge oil passage 32 and communicates with the oil cooler 7.

[0029] The suction oil passage 31, the discharge oil passage 32, and the cooler inlet oil passage 33 are composed of grooves formed in the vertical wall portion 5A and a single flat plate member 27 that covers the grooves.

[0030] As shown in Figure 4, the suction oil passage 31 is formed so that its upper end is located below the oil pump 30 and communicates with the oil pump 30 via an intake port, and extends downward from there. The lower end of the suction oil passage 31 is bent slightly to the rear and communicates with the outlet 26A of the strainer 26. The discharge oil passage 32 is formed so that its lower end is located above the oil pump 30 and communicates with the oil pump 30 via a discharge port, and extends diagonally upward and backward from there, with a communication hole 32B formed at its upper end through which oil flows towards the lubricating object. The cooler inlet oil passage 33 is formed so that its upper end communicates with the lower end of the discharge oil passage 32 located above the oil pump 30, curves along the outer circumference of the rear of the oil pump 30 (the surrounding wall in contact with the rear side of the outer rotor), and extends downward along the suction oil passage 31. More specifically, the cooler inlet oil passage 33 and the suction oil passage 31 are formed in the vertical wall section 5A so as to extend vertically and be close to each other. The cooler inlet oil passage 33 and the suction oil passage 31 are separated by a central wall 37 erected between them, and the upper part of this central wall 37 is connected to the outer circumference behind the recess of the vertical wall section 5A that houses the oil pump 30 (the surrounding wall that is in contact with the rear side of the outer rotor). Although the cooler inlet oil passage 33 and the suction oil passage 31 are formed side by side in the vertical wall section 5A, the oil flows in opposite directions. That is, oil flows downward in the cooler inlet oil passage 33, and oil flows upward in the suction oil passage 31. Bosses 39 with screw holes 38 into which bolts that fix the plate member 27 are screwed are formed on the central wall 37, and these bosses 39 are formed to increase the thickness of the central wall 37, and by connecting the central wall 37 and the plate member 27, gaps are eliminated and oil leakage between the two oil passages is suppressed. The cooler inlet oil passage 33 and the suction oil passage 31 are separated by a central wall 37 and formed side by side in the vertical wall section 5A. Therefore, a single flat plate member 27 can be attached to cover the two grooves that constitute the oil passages, thereby forming each oil passage. The upper part of the plate member 27 is fastened together with the housing 5C that holds the bearing 5B, and is attached to the vertical wall section 5A so as to be pressed against the housing 5C.In other words, the plate member 27, together with the recess in the vertical wall portion 5A, creates a pump housing space for the oil pump 30.

[0031] As shown in Figure 2, a communication hole 31A, which serves as the outlet for the oil cooler 7 into which oil that has passed through the oil cooler 7 flows, is formed at the lower part of the suction oil passage 31, and the oil cooler 7 is connected to it. Also, at the lower part of the suction oil passage 31, the outlet 26A of the strainer 26, through which oil flows out of the strainer 26, is connected via a communication hole 27A in the plate member 27. In other words, the outlet 26A of the strainer 26 is located at the lower end of the suction oil passage 31. Regarding the location of communication with the suction oil passage 31, the communication hole 31A, which serves as the outlet for the oil cooler 7, is located at a higher position than the location to which the outlet 26A of the strainer 26 is connected, and is also located closer to the oil pump 30 than the outlet 26A of the strainer 26. A communication hole 27A with the same diameter as the outlet 26A is formed in the plate member 27 at a position corresponding to the outlet 26A of the strainer 26. The oil flowing out from the outlet 26A of the strainer 26 enters the suction oil passage 31 through the communication hole 27A. In this way, the suction oil passage 31 can also serve as the oil passage from the oil cooler 7 to the oil pump 30, thus simplifying the oil passage configuration. Incidentally, the communication hole 33A formed in the cooler inlet oil passage 33, which allows oil to flow to the oil cooler 7, is formed at the lower end of the cooler inlet oil passage 33 and is located at approximately the same height as the outlet 26A of the strainer 26 and the communication hole 27A. Furthermore, the communication hole 33A is located lower than the communication hole 31A, which is the outlet of the oil cooler 7. This height relationship suppresses the leakage of oil from the oil cooler 7 when the oil pump 30 is stopped. In other words, with the oil pump 30 stopped, the suction oil passage 31 has a strainer 26 connected to its lower part, so the oil in the suction oil passage 31 flows back into the strainer 26 and is discharged into the oil storage chamber 25, but the oil in the oil cooler 7 does not drain out and remains in the oil cooler 7. The cooler inlet oil passage 33 has a communication hole 33A that allows oil to flow into the oil cooler 7, but it extends above the communication hole 33A and reaches a higher position than the communication hole 31A, with the communication hole 33A being at the very bottom, so the oil in the cooler inlet oil passage 33 flows into the oil cooler 7 and accumulates in the oil cooler 7.

[0032] As shown in Figure 5, the oil filtered by the strainer 26 enters the suction oil passage 31 from the outlet 26A and is drawn up to the oil pump 30. The oil pump 30 discharges the oil and pumps it into the oil passage 32.

[0033] The oil pumped by the oil pump 30 into the discharge oil passage 32 enters an oil passage (not shown) through the communication hole 32B. The oil that enters the oil passage (not shown) cools the power generation motor 21 (labeled MG1 in the figure) and the drive motor 23 (labeled MG2 in the figure). The oil that has cooled the power generation motor 21 and the drive motor 23 flows down, lubricating other lubricated objects, and returns to the oil storage chamber 25.

[0034] A portion of the oil pumped by the oil pump 30 into the discharge oil passage 32 enters the cooler inlet oil passage 33 from the branching section 32A, descends through the cooler inlet oil passage 33, and is introduced into the oil cooler 7 through the communication hole 33A. The oil cooled in the oil cooler 7 is introduced into the suction oil passage 31 from the communication hole 31A, which is the outlet of the oil cooler 7, and is mixed with the oil from the strainer 26 that is sucked in from the outlet 26A, then sucked into the oil pump 30 and pumped again into the discharge oil passage 32. Thus, the drive unit 3 of the present invention employs a parallel cooling system in which a portion of the oil is diverted from the discharge oil passage 32 to the oil cooler 7 to cool the oil, rather than a series cooling system in which the oil cooler 7 is installed in the middle of the discharge oil passage 32 and the oil must always pass through it.

[0035] As shown in Figure 1, the drive unit 3 of the present invention, when viewed from the left, has the drive motor 23 positioned behind the power generation motor 21. The differential gear 16 is positioned below the drive motor 23. The oil cooler 7 is located in the front portion of the vertical wall 5A on the outer surface of the case 3A, below the power generation motor 21 and in front of the differential gear 16.

[0036] As shown in Figure 4, the discharge oil passage 32 is positioned above the oil pump 30 at its lower end (the upstream end in the oil flow) and extends diagonally upward and backward from there. In other words, the discharge oil passage 32 directs the oil flowing upward from the oil pump 30 through the discharge port, bending its flow direction diagonally upward and backward. This flow direction is opposite to the direction of rotation of the rotor at the top of the oil pump 30. In other words, it extends linearly, inclined with respect to the radial direction from the center of the oil pump 30. More specifically, the discharge oil passage 32 extends linearly, inclined backward with respect to the radial direction (directly upward) from the center of the oil pump 30.

[0037] Furthermore, the cooler inlet oil passage 33 branches off from the discharge oil passage 32 near the discharge port of the oil pump 30, at an angle α backward relative to the extension direction of the discharge oil passage 32. In other words, directly above the oil pump 30, the lower end of the discharge oil passage 32 (the upstream end in the oil flow) is a branch section 32A as shown in Figure 4, and the cooler inlet oil passage 33 branches off from the discharge oil passage 32 at this branch section 32A. The discharge oil passage 32 bends the oil flowing upward from the oil pump 30 diagonally backward, but the cooler inlet oil passage 33, which is positioned to bend further, opens its entrance to the cooler inlet oil passage 33 at the branch section 32A on the inside of the bend in the discharge oil passage 32, and the cooler inlet oil passage 33 opens in a position where it is difficult for oil to flow in. In particular, the opening of the cooler inlet oil passage 33 is constructed using the edge of the surrounding wall that is in contact with the rear side of the outer rotor of the oil pump 30, and the opening edge on the side that is not part of the surrounding wall is positioned behind the edge of the surrounding wall and is formed to face slightly upward. This configuration of the opening in the cooler inlet oil passage 33 makes it possible to direct the opening downstream of the flow of oil from the oil pump 30 flowing out of the discharge port, thereby suppressing the flow of oil into the cooler inlet oil passage 33.

[0038] Furthermore, the discharge oil passage 32 is formed with a larger cross-sectional area than the cooler inlet oil passage 33. In other words, the cooler inlet oil passage 33 is formed with a smaller cross-sectional area than the discharge oil passage 32. In addition, the upper part of the cooler inlet oil passage 33 is curved along the surrounding wall that contacts the rear side of the outer rotor of the oil pump 30, and the cooler inlet oil passage 33 has bends and protruding clamping bosses. This prevents too much oil from being diverted from the discharge oil passage 32 to the cooler inlet oil passage 33, thereby suppressing oil overcooling. In this configuration, if the amount of oil diverted from the discharge oil passage 32 to the cooler inlet oil passage 33 is less than the optimal amount, and it is desired to increase the amount of oil diverted to the cooler inlet oil passage 33, the cross-sectional area of ​​the communication hole 32B downstream of the discharge oil passage 32 can be reduced to increase the amount of oil diverted. Specifically, by making the opening area of ​​the communication hole 32B downstream of the discharge oil passage 32 smaller than the opening area of ​​the communication hole 33A downstream of the cooler inlet oil passage 33, and by making the communication hole 32B function as an orifice, the amount of oil passing through the communication hole 32B downstream of the discharge oil passage 32 decreases, and the amount of oil passing through the communication hole 33A downstream of the cooler inlet oil passage 33 increases. This allows for the optimization of the distribution between the oil flowing straight through the discharge oil passage 32 and the oil diverted to the cooler inlet oil passage 33.

[0039] As described above, in this embodiment, oil passages for cooling the power generation motor 21 and the drive motor 23 are formed in the case 3A. The drive motor 23 is positioned behind the power generation motor 21, and the differential gear 16 is positioned below the drive motor 23. The oil cooler 7 for cooling the oil is positioned on the outer surface of the case 3A, below the power generation motor 21 and in front of the differential gear 16.

[0040] This allows the oil cooler 7 to be positioned in a recessed area of ​​the case 3A, below the power generation motor 21 and in front of the differential 16. This reduces the protrusion of the oil cooler 7 from the case 3A, allowing the drive unit 3 to be miniaturized. Furthermore, because the oil cooler 7 can be positioned at the front of the case 3A, ahead of the differential 16, the airflow from the vehicle can hit the oil cooler 7, promoting oil cooling. As a result, the overall size of the drive unit 3 can be reduced by suppressing the protrusion of the oil cooler 7 from the case 3A, and the cooling performance of the oil cooler can be improved.

[0041] In this embodiment, the case 3A supports the input shaft 10 and has a vertical wall portion 5A that extends vertically to demarcate the inside and outside of the case 3A. An oil pump 30 is provided on the vertical wall portion 5A coaxially with the input shaft 10, a strainer 26 is attached to the lower part of the vertical wall portion 5A, and an oil cooler 7 for cooling the oil is provided at the lower part of the vertical wall portion 5A on the outer surface of the case 3A. In other words, the strainer 26 and the oil cooler 7 are arranged on the front and back of the lower part of the vertical wall portion 5A. The vertical wall portion 5A has a suction oil passage 31 that communicates with the strainer 26 and the oil pump 30, a discharge oil passage 32 that communicates with the oil pump 30 and the object to be lubricated, and a cooler inlet oil passage 33 that branches off from the discharge oil passage 32 and communicates with the oil cooler 7. In other words, the strainer 26 and the oil cooler 7 are arranged on the front and back of the lower part of the vertical wall portion 5A. The lower part of the vertical wall section 5A is located between the strainer 26 and the oil cooler 7. The suction oil passage 31 and the cooler inlet oil passage 33 are located between the strainer 26 and the oil cooler 7. The strainer 26 is located on one side of the suction oil passage 31 and the cooler inlet oil passage 33, and the oil cooler 7 is located on the other side of the suction oil passage 31 and the cooler inlet oil passage 33.

[0042] As a result, the strainer 26, oil pump 30, and oil cooler 7 can be arranged together in a single vertical wall section 5A of case 3A, and the suction oil passage 31 and the cooler inlet oil passage 33 can be formed together. Therefore, the oil passages passing through the oil cooler 7 can be shortened, and the overall size can be reduced.

[0043] In this embodiment, the suction oil passage 31 is connected to the communication hole 31A, which serves as the outlet for the oil cooler 7.

[0044] As a result, the intake oil passage 31 can also serve as the oil passage from the oil cooler 7 to the oil pump 30, thus simplifying the configuration of the oil passages.

[0045] In this embodiment, the cooler inlet oil passage 33 and the suction oil passage 31 are formed in the vertical wall portion 5A so as to be close to each other and extending in the vertical direction. The suction oil passage 31 and the cooler inlet oil passage 33 are composed of a groove formed in the vertical wall portion 5A and a single plate member 27 that covers the groove.

[0046] This simplifies the configuration of the suction oil passage 31 and the cooler inlet oil passage 33, making them easy to form and improving productivity.

[0047] While embodiments of the present invention have been disclosed, it will be apparent to those skilled in the art that modifications can be made without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims. [Explanation of Symbols]

[0048] 1 vehicle 2 engines 3. Drive system (vehicle drive system) 3A Case 5 Left Case (Case) 5A Vertical wall section 7. Oil cooler 10 input axes 16 Differential device 21. Power generation motor 23 Drive motor 26 Strainer 27 Plate members 30 Oil pump 31 Intake oil passage 31A communication hole 32 Discharge oil passage 33 Cooler inlet oil passage

Claims

1. A vehicle drive system comprising an input shaft into which power is input from an engine, a generator motor that generates electricity using the power input to the input shaft, a drive motor that operates using the electricity generated by the generator motor, and a differential that distributes the power generated by the drive motor to the left and right drive wheels, in a case that houses these components, An oil passage is formed in the case through which oil for cooling the power generation motor and the drive motor passes. The drive motor is positioned behind the power generation motor. The differential is positioned below the drive motor. A vehicle drive system characterized in that an oil cooler for cooling the oil is located on the outer surface of the case, below the power generation motor, and in front of the differential.

2. The case has vertical walls that support the input shaft and extend vertically to separate the inside and outside of the case. An oil pump is provided in the aforementioned vertical wall portion coaxially with the input shaft. A strainer is attached to the lower part of the aforementioned vertical wall section. An oil cooler for cooling the oil is provided at the lower part of the vertical wall portion on the outer surface of the case. The vehicle drive device according to claim 1, characterized in that the vertical wall portion is formed with a suction oil passage communicating with the strainer and the oil pump, a discharge oil passage communicating with the oil pump and the object to be lubricated, and a cooler inlet oil passage branching off from the discharge oil passage and communicating with the oil cooler.

3. The vehicle drive device according to claim 2, characterized in that the outlet of the oil cooler is in communication with the suction oil passage.

4. The cooler inlet oil passage and the suction oil passage are formed in the vertical wall portion so as to be close to each other and extending in the vertical direction, The vehicle drive device according to claim 2 or 3, characterized in that the suction oil passage and the cooler inlet oil passage are composed of a groove formed in the vertical wall and a single plate member covering the groove.

5. A vehicle drive system comprising a case for housing an oil filter strainer, The case has vertical wall portions that extend vertically to separate the inside and outside of the case, The strainer is attached to the inner surface of the vertical wall portion. A vehicle drive system characterized in that an oil cooler for cooling oil is mounted on the outer surface of the vertical wall portion at a position opposite to the strainer.

6. An oil passage through which oil passes is formed in the vertical wall portion. The vehicle drive device according to claim 5, characterized in that the strainer and the oil cooler are in communication with the oil passage.

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