Vehicle drive device

Abstract

This vehicle drive device (1) comprises: a main case (51) having a main chamber (5); and a sub-case (52) having a sub-chamber (6). The main chamber (5) accommodates a pair of motors (10). The main case (51): supports the pair of motors (10) which are mutually spaced apart such that motor shafts (15), which are output shafts of the pair of motors (10), are coaxially disposed; and supports, at positions further to one side than the motor shafts (15) in a top view, wheel shafts (14) which connect to left and right wheels. The sub-chamber (6) accommodates the inverter (12) and is provided adjacent to the main chamber (5) on the other side with respect to the motor shafts (15) in a top view.

Description

Vehicle drive device

[0001] The present invention relates to a vehicle drive device including a motor and an inverter.

[0002] In vehicle drive devices mounted on electric vehicles and hybrid vehicles, a structure is known in which a motor and a motor control circuit (inverter) are housed in the same case as an electromechanical integrated unit. For example, a vehicle drive device is known in which a motor is incorporated in a lower portion of a case, and a motor control circuit is arranged in an upper portion of the case. With such a configuration, the size of the device can be reduced (see, for example, Patent Document 1).

[0003] Japanese Unexamined Patent Publication No. 2024-099433

[0004] When arranging a vehicle drive device in a narrow space, the height dimension of the vehicle drive device may cause interference with surrounding structures. Particularly, in a drive device for rear wheels mounted under the floor of a vehicle, it is not only necessary to prevent interference with the underfloor, but also it is necessary to ensure a clearance dimension from the road surface to the drive device, so that the mounting space is severely restricted. Therefore, depending on the size of the vehicle drive device, the floor surface of the vehicle must be raised, which reduces the cabin space.

[0005] On the other hand, when the height of the floor surface cannot be changed, it is necessary to reduce the size of the vehicle drive device. In this case, the size of the motor incorporated in the vehicle drive device inevitably becomes small, and there is a possibility that desired vehicle drive performance cannot be obtained. As described above, existing vehicle drive devices have a problem that it is difficult to improve vehicle mountability while maintaining desired vehicle drive performance.

[0006] One object of the present invention, which was devised in view of the above problems, is to provide a vehicle drive device that improves vehicle mountability while maintaining vehicle drive performance. It should be noted that the present invention is not limited to this object, and achieving functions and effects that are derived from each configuration shown in the "Description of Embodiments" described later and cannot be obtained by conventional techniques is also positioned as another object of the present invention.

[0007] The disclosed vehicle drive system can be realized in the following embodiments (examples of application) and solves at least some of the above-mentioned problems. Each of embodiments from Embodiment 2 onward is an additional embodiment that can be appropriately selected and each of them is an embodiment that can be omitted. None of embodiments from Embodiment 2 onward disclose any embodiments or configurations that are indispensable to this case.

[0008] Embodiment 1. The disclosed vehicle drive system comprises a pair of motors and an inverter for driving the left and right wheels of a vehicle, and includes a main case portion having a main chamber for housing the pair of motors, supporting the pair of motors spaced apart from each other such that the motor shafts, which are the output shafts of the pair of motors, are arranged coaxially, and supporting the wheel shafts connected to the left and right wheels at a position to one side of the motor shafts when viewed from above, and a sub-case portion having a sub-chamber for housing the inverter, and provided adjacent to the main chamber in a direction to the other side of the motor shafts when viewed from above.

[0009] Embodiment 2. With respect to embodiments including Embodiment 1 described above, the vehicle drive device preferably comprises a recess on the upper surface of the main case portion, formed by recessing downward the portion sandwiched between the pair of motors in a top view, a partition wall forming the boundary between the main chamber and the sub-chamber and extending above the recess, and a power supply line connecting the battery and the inverter and supplying power from the battery to the inverter, wherein the power supply line is routed to pass inside the recess and through the portion of the partition wall above the recess.

[0010] Embodiment 3. With respect to embodiments including Embodiment 1 described above, the vehicle drive unit comprises an inverter cover that forms part of the sub-case portion and closes the other end of the sub-compartment; a control connector provided on the inverter cover to which a harness for controlling the operating state of the inverter is connected; and a suspension cross positioned in the other direction from the sub-compartment and extending in the vehicle width direction of the vehicle, wherein the control connector is positioned above the suspension cross.

[0011] Embodiment 4. With respect to embodiments including Embodiment 3 described above, it is preferable that the vehicle drive unit is positioned in the other direction from the sub-compartment, is fixed to the floor panel of the vehicle, and includes a floor cloth extending in the vehicle width direction, and that the control connector is extended diagonally downward so as it moves away from the outer surface of the inverter cover, it moves away from the floor cloth.

[0012] Embodiment 5. With respect to embodiments including Embodiment 3 described above, it is preferable that the vehicle drive unit is provided on the inverter cover and includes a refrigerant nipple to which a refrigerant pipe for cooling the inverter is connected, and that the refrigerant nipple is positioned above the suspension cross.

[0013] Embodiment 6. With respect to embodiments including Embodiment 1 described above, the vehicle drive device comprises an inverter cover that forms part of the sub-case portion and closes the other end of the sub-chamber, and a terminal block provided inside the sub-case portion at the connection point between the motor-side three-phase wires extending from each of the pair of motors and the inverter-side three-phase wires extending from the inverter, wherein the inverter cover has a service hole formed at a position in the other direction from the terminal block, a boss formed in the shape of a ridge surrounding the outer circumference of the service hole, and a bulge portion formed by bulging the inner and outer surfaces of the inverter cover toward the outside of the sub-chamber, and it is preferable that the boss is positioned to overlap with the bulge portion.

[0014] Embodiment 7. With respect to embodiments including Embodiment 6 described above, it is preferable that the vehicle drive device is provided with a flat plate-shaped cover attached to the outer end surface of the boss to close the service hole, and that the outer end surface of the boss is formed to be in the same plane as the outer surface of the bulge, or that the outer end surface of the boss is formed to protrude in a direction away from the sub-chamber than the outer surface of the bulge.

[0015] In the disclosed vehicle drive system, a sub-compartment is provided adjacent to the main compartment in a top view, on the opposite side from the motor shaft (opposite to the one-sided direction from the motor shaft to the wheel axle), and the inverter is housed in this sub-compartment. This reduces the height dimension of the vehicle drive system. Therefore, it is possible to provide a vehicle drive system that improves vehicle mountability while maintaining vehicle driving performance.

[0016] This is a perspective view showing the external appearance of a vehicle drive unit. This is a cross-sectional view illustrating the internal structure of a vehicle drive unit. This is a perspective view showing the external appearance of a vehicle drive unit. This is a longitudinal cross-sectional view showing the peripheral structure of a vehicle drive unit. This is a rear view of a vehicle drive unit. (A) is a cross-sectional view illustrating the structure of a service hole (cross-sectional view A-A in Figure 5), and (B) is a cross-sectional view showing a modified example of (A).

[0017] [1. Configuration] Figure 1 is a perspective view showing the external appearance (front, top, and left side) of a vehicle drive unit 1 as an embodiment, and Figure 2 is a cross-sectional view illustrating the internal structure of the vehicle drive unit 1. The front, rear, left, right, up, and down directions in the figures are determined relative to the vehicle on which the vehicle drive unit 1 is mounted, and are represented by the symbols F (front), B (rear), L (left), R (right), U (up), and D (down).

[0018] The vehicle drive system 1 comprises a pair of motors 10 and an inverter 12 that drive the left and right wheels of the vehicle, and is installed in electric vehicles (EVs), hybrid vehicles (HEVs), and plug-in hybrid vehicles (PHEVs). A plug-in hybrid vehicle refers to a hybrid vehicle that can be externally charged to or powered from the battery. Plug-in hybrid vehicles are provided with a charging port (inlet) for inserting a charging cable that receives power from an external charging facility, and an outlet for external power supply. In this embodiment, the vehicle drive system 1 drives the rear wheels of the vehicle.

[0019] Each of the pair of motors 10 is, for example, a synchronous motor (synchronous AC motor) and can operate independently of each other. As shown in Figure 2, each motor 10 has a stator 41 and a rotor 42. The stator 41 is fixed to the center case 2 or the side cover 3, and the rotor 42 is fixed to the motor shaft 15, which is the output shaft. The pair of motors 10 are arranged so that their respective motor shafts 15 are coaxially arranged and spaced apart from each other. In this embodiment, when the vehicle drive unit 1 is mounted on the vehicle, the motor shafts 15 are arranged so that they extend in the vehicle width direction. Note that other AC motors (induction motors, commutator motors) may be used instead of synchronous motors.

[0020] The power to rotate the motor 10 is supplied from a battery (not shown) or an on-board power generation system (generator, fuel cell, diesel power generation system, etc.) mounted on the vehicle. Generally, the power supplied from the battery or on-board power generation system is DC power. The DC power is converted to AC power by the inverter 12 and then supplied to each of the pair of motors 10.

[0021] The driving force output from each motor shaft 15 is transmitted to the left and right wheels of the vehicle via the gear mechanism 11. The gear mechanism 11 amplifies the torque difference between the pair of motors 10 and transmits it to each of the left and right wheels. The gear mechanism 11 includes, for example, a reduction mechanism, a speed change mechanism, a differential gear mechanism, a planetary gear mechanism, etc. The wheel axles 14 connecting the gear mechanism 11 to each of the left and right wheels are arranged parallel to the motor shafts 15.

[0022] In this embodiment, as shown in Figure 2, the wheel axle 14 is positioned in front of the motor shaft 15 when viewed from above with the vehicle drive unit 1 mounted on the vehicle. Note that Figure 2 shows a cross-section in a plane (or curved surface) passing through the wheel axle 14 and motor shaft 15 for convenience. The height positions of the wheel axle 14 and motor shaft 15 do not necessarily coincide.

[0023] If you want to express the positional relationships between the elements of the vehicle drive unit 1 without using the vehicle as a reference, you can use the positional relationship between the wheel axle 14 and the motor shaft 15 as the reference. For example, in a top view of the vehicle drive unit 1, the direction from the motor shaft 15 toward the wheel axle 14 may be defined as the one-sided direction, and the opposite direction may be defined as the other-sided direction. In this embodiment, the one-sided direction corresponds to the front of the vehicle, and the other-sided direction corresponds to the rear of the vehicle. Depending on the orientation in which the vehicle drive unit 1 is mounted on the vehicle, the correspondence between the one-sided and other-sided directions and the front and rear of the vehicle will change.

[0024] As shown in Figure 1, a pair of motors 10, a gear mechanism 11, and an inverter 12 are housed in the center case 2 of the vehicle drive unit 1. The center case 2 comprises a main case portion 51 and a sub-case portion 52. The main case portion 51 and the sub-case portion 52 are integrally defined, for example, during the casting of the center case 2. A main chamber 5 is provided inside the main case portion 51, and a sub-chamber 6 is provided inside the sub-chamber 6.

[0025] The main chamber 5 is a container-shaped space that houses a pair of motors 10 and a gear mechanism 11. As shown in Figure 2, the main case portion 51 supports the pair of motors 10 spaced apart from each other so that the motor shafts 15 are arranged coaxially in the main chamber 5, and also supports the wheel axles 14 connected to the left and right wheels at a position one side of the motor shafts 15 when viewed from above. The main chamber 5 is formed in a shape where the left and right ends (ends in the extending direction of the wheel axles 14) are open to the outside of the center case 2, and the front, rear, upper and lower ends (ends in one side direction and the other side direction, and upper and lower ends) are closed. The left and right ends of the main chamber 5 are closed by the side covers 3. The side covers 3 constitute a part of the main case portion 51. The wheel axles 14 are provided so as to pass through the side covers 3.

[0026] The sub-chamber 6 is a container-shaped space that houses the inverter 12. The sub-case portion 52 supports the inverter 12 so that it is stably fixed in the sub-chamber 6. As shown in Figure 2, the sub-chamber 6 is provided adjacent to the rear of the main chamber 5 (in the direction other than the motor shaft 15 relative to the main chamber 5). The sub-chamber 6 is formed with an open rear end (the end in the other direction) and closed upper, lower, left, right, and front ends (the ends in the extending direction of the wheel axle 14, the upper and lower ends, and the ends in the one-sided direction). The rear end of the sub-chamber 6 (the end of the sub-chamber 6 in the other direction) is closed by the inverter cover 4. The inverter cover 4 constitutes a part of the sub-case portion 52.

[0027] Here, assuming that one side is the front direction of the vehicle drive unit 1, the sub-compartment 6 can be considered to be located at the rear of the main compartment 5. In other words, the inverter 12 housed in the sub-compartment 6 is supported on the rear side of the center case 2, as if it were being carried on the back of the main compartment 5 where the motor 10 is housed. This type of structure for the vehicle drive unit 1 is called a backpack structure (or backpack-type structure).

[0028] As shown in Figure 1, a recess 8 is provided on the upper surface of the center case 2. The recess 8 is formed by recessing the portion of the upper surface of the main case portion 51 of the center case 2 that is sandwiched between the pair of motors 10 when viewed from above. A partition wall 7 is provided at the boundary between the main chamber 5 and the sub-chamber 6 (the boundary between the main case portion 51 and the sub-case portion 52). Inside the center case 2, the main chamber 5 and the sub-chamber 6 are separated by the partition wall 7. On the other hand, as shown in Figure 1, this partition wall 7 extends above the recess 8. In other words, a part of the partition wall 7 becomes part of the outer surface of the center case 2 and forms the rear end surface (front end surface of the sub-chamber 6) on the inside of the recess 8.

[0029] Inside the recess 8, a power supply line 13 (PN line) is routed. The power supply line 13 is a cable that connects the battery (or on-board power generation system) to the inverter 12 in order to convert the power required to drive the motor 10 into power for the inverter 12. As shown in Figure 1, the power supply line 13 is routed through the inside of the recess 8 and through the portion of the partition wall 7 above the recess 8. After passing through the partition wall 7, the power supply line 13 enters the sub-chamber 6 and is connected to the inverter 12 inside the sub-chamber 6. By routing the power supply line 13 using the recess 8 in this way, the limited space is utilized efficiently.

[0030] As shown in Figure 2, the inverter 12 includes a base plate 16, a semiconductor module 17, and a capacitor 18. The base plate 16 is a plate member fixed to the inverter cover 4 and serves as the base for the semiconductor module 17 and the capacitor 18. The base plate 16 is preferably made of a material with low thermal resistance. A coolant circuit for cooling the inverter 12 is provided inside or on the surface of the base plate 16.

[0031] The semiconductor module 17 is a power module formed by creating a three-phase bridge circuit on an electronic circuit board, including multiple switching elements and diodes. Three-phase AC power is generated by intermittently switching the connection state of each switching element. Semiconductor elements such as thyristors, IGBTs (Insulated Gate Bipolar Transistors), and power MOSFETs (Metal Oxide Semiconductor Field-Effect Transistors) are used as switching elements. In the example shown in Figure 2, the semiconductor module 17 is fixed to the front side (the side closer to the main chamber 5) of the surface of the base plate 16. The same number of semiconductor modules 17 as the motor 10 (i.e., two) are provided.

[0032] The capacitor 18 is an electronic component that smooths the power supplied to the motor 10. The capacitor 18 is interposed on the input or output side of the semiconductor module 17 and functions to stabilize the input voltage and output current. In the example shown in Figure 2, the capacitor 18 is fixed to the rear side (the side closer to the inverter cover 4) of the surface of the base plate 16.

[0033] Figure 3 is a perspective view showing the external appearance (rear, top, and left side) of the vehicle drive unit 1, and Figure 4 is a longitudinal cross-sectional view showing the surrounding structure of the vehicle drive unit 1. A suspension cross 31 (suspension cross member) and a floor cross 33 (floor cross member) are provided on the rear side of the vehicle drive unit 1 mounted on the vehicle. Each of the suspension cross 31 and floor cross 33 is formed, for example, in a hollow cylindrical shape and extends in the vehicle width direction. The suspension cross 31 connects, for example, the right wheel suspension device and the left wheel suspension device. The floor cross 33 is fixed to the lower side of the floor panel 32 in order to reinforce the floor panel 32. As shown in Figure 4, the suspension cross 31 and floor cross 33 are arranged substantially parallel to each other with a predetermined gap in the vertical direction. In the example shown in Figure 4, the suspension cross 31 is positioned directly below the floor cross 33 (at approximately the same front-rear position, overlapping position in top view).

[0034] As shown in Figures 3 and 4, a control connector 21 and a refrigerant nipple 22 are provided protruding from the rear outer surface of the inverter cover 4. The control connector 21 is the part to which a harness for controlling the operating state of the inverter 12 is connected. Preferably, the control connector 21 is positioned above the suspension cloth 31 and below the floor cloth 33 on the outer surface of the inverter cover 4. In other words, it is preferable that the control connector 21 is disposed within the protective space sandwiched between the suspension cloth 31 and the floor cloth 33. This ensures that the lower part of the control connector 21 is covered by the suspension cloth 31, improving the protection of the control connector 21 against, for example, flying stones from the road surface.

[0035] Furthermore, as shown in Figure 4, if the distance between the control connector 21 and the floor cloth 33 is relatively short, the extension direction of the control connector 21 may be changed to increase that distance. For example, it is preferable that the control connector 21 extends diagonally downward so that it moves away from the floor cloth 33 as it moves away from the outer surface of the inverter cover 4. It is preferable that the extension direction of the control connector 21 is set so that a predetermined distance is secured from both the suspension cloth 31 and the floor cloth 33. This prevents interference between the control connector 21 and the suspension cloth 31 and the floor cloth 33 (in particular, interference with the floor cloth 33 when the vehicle drive unit 1 vibrates).

[0036] The refrigerant nipple 22 is the part to which the refrigerant piping for cooling the inverter 12 is connected. The refrigerant flowing in through the refrigerant nipple 22 is introduced into the aforementioned refrigerant circuit. Similar to the control connector 21, the refrigerant nipple 22 is preferably positioned on the outer surface of the inverter cover 4 above the suspension cloth 31 and below the floor cloth 33. In other words, the refrigerant nipple 22 is preferably disposed within the protective space sandwiched between the suspension cloth 31 and the floor cloth 33. This ensures that the lower part of the refrigerant nipple 22 is covered by the suspension cloth 31, improving the protection of the refrigerant nipple 22 against, for example, flying stones from the road surface.

[0037] The extension direction of the refrigerant nipple 22 may be set in the same way as that of the control connector 21. If the distance between the refrigerant nipple 22 and the floor cloth 33 is relatively short, the extension direction of the refrigerant nipple 22 may be changed to increase that distance. For example, it is preferable that the refrigerant nipple 22 extends diagonally downward so that it moves away from the floor cloth 33 as it moves away from the outer surface of the inverter cover 4. It is preferable that the extension direction of the refrigerant nipple 22 is set so that a predetermined distance is secured from both the suspension cloth 31 and the floor cloth 33. This prevents interference between the refrigerant nipple 22 and the suspension cloth 31 and the floor cloth 33 (in particular, interference with the floor cloth 33 when the vehicle drive unit 1 vibrates).

[0038] Figure 5 is a rear view of the vehicle drive unit 1, and Figure 6(A) is a cross-sectional view taken along line A-A in Figure 5. Inside the sub-compartment 6 (inside the sub-case 52), a terminal block 26 is provided, interposed on the three-phase lines connecting each of the pair of motors 10 to the inverter 12. The terminal block 26 is provided at the connection point between the motor-side three-phase lines 27 extending from each of the pair of motors 10 and the inverter-side three-phase lines 28 extending from the inverter 12.

[0039] The connection work of the motor-side three-phase wire 27 and the inverter-side three-phase wire 28 is performed after the motor 10 and inverter 12 are assembled into the center case 2 of the vehicle drive unit 1. In this embodiment, the inverter 12 is fixed to the inverter cover 4. Therefore, the connection work of the motor-side three-phase wire 27 and the inverter-side three-phase wire 28 is performed after the inverter cover 4 is attached to the center case 2.

[0040] The inverter cover 4 is provided with a service hole 23, which is a work opening for performing the above-mentioned work. The service hole 23 is located on the inverter cover 4 opposite the terminal block 26 (in the direction away from the terminal block 26). As a result, as shown in Figure 5, the terminal block 26 is visible inside the service hole 23 when viewed from the rear of the vehicle drive unit 1.

[0041] Furthermore, the inverter cover 4 is provided with a boss 24 and a bulge 19. The boss 24 is a part that reinforces the service hole 23 and is formed in a levee-like shape that surrounds the outer circumference of the service hole 23. The bulge 19 is a part that is formed in a bulging shape to correspond to the shape of the inverter 12. The bulge 19 is formed in a shape that bulges the inner and outer surfaces of the inverter cover 4 toward the outside of the sub-chamber 6 (towards the rear of the vehicle). Inside the bulge 19, the inverter 12 is arranged as shown in Figure 2. In this embodiment, the shape of the bulge 19 is rectangular, corresponding to the shape of the capacitor 18.

[0042] The boss 24 is provided at a position overlapping the bulging portion 19. Here, among the outer surfaces of the inverter cover 4, the surface from which the control connector 21 and the refrigerant nipple 22 protrude is referred to as the reference surface. The bulging portion 19 and the boss 24 are formed in a shape bulging toward the vehicle rear beyond the reference surface. Further, the bulging portion 19 and the boss 24 are integrally formed so as not to be separated from each other by the reference surface.

[0043] As shown in FIG. 6(A), a flat plate-shaped lid 25 that closes the service hole 23 is attached to the boss outer end surface 30 (the outer end surface of the boss 24). FIG. 5 shows a state where one of the two service holes 23 (the right side in the figure) is closed by the lid 25, and the other (the left side in the figure) is open. Further, as shown in FIG. 6(A), the boss outer end surface 30 is preferably formed to be flush with the bulging portion outer surface 29 (the outer surface of the bulging portion 19). This facilitates attachment of the lid 25 so as to straddle the bulging portion outer surface 29 and the boss outer end surface 30 that are flush with each other.

[0044] Note that, as shown in FIG. 6(B), the boss outer end surface 30 may be formed to protrude from the bulging portion outer surface 29 in a direction away from the auxiliary chamber 6 (the outward direction of the auxiliary chamber 6, toward the vehicle rear). That is, the boss outer end surface 30 may be slightly protruded with reference to the bulging portion outer surface 29. At least with such a configuration, interference between the lid 25 and the bulging portion 19 is prevented.

[0045] [2. Effects] (1) The vehicle drive device 1 described above includes a main case portion 51 having a main chamber 5 and an auxiliary case portion 52 having an auxiliary chamber 6. The main chamber 5 accommodates a pair of motors 10, and the main case portion 51 supports the pair of motors 10 in a state of being spaced apart from each other such that motor shafts 15, which are output shafts of the pair of motors 10, are coaxially arranged, and also supports a wheel shaft 14 connected to left and right wheels at a position on one side of the motor shafts 15 (toward the front of the vehicle) in a top view. The auxiliary chamber 6 accommodates the inverter 12, and is provided adjacent to the main chamber 5 on the other side of the motor shafts 15 (toward the rear of the vehicle) in a top view.

[0046] As described above, housing the inverter 12 in the auxiliary chamber 6 adjacent to the other side of the main chamber 5 reduces the height dimension of the vehicle drive device 1 compared to arranging the inverter 12 above the main chamber 5. In particular, in the vehicle drive device 1 that drives the rear wheels of a vehicle, occurrence of interference with the floor panel 32 can be suppressed. Further, by arranging the vehicle drive device 1 as close as possible to the floor panel 32, the clearance dimension from the road surface to the vehicle drive device 1 can be easily secured. Accordingly, the vehicle drive device 1 with improved vehicle mountability while maintaining vehicle driving performance can be provided.

[0047] (2) The vehicle drive device 1 described above includes a recess 8, a partition wall 7, and a power feed line 13. The recess 8 is formed on the upper surface of the main case portion 51 (the main chamber 5) by downwardly recessing a portion sandwiched between the pair of motors 10 in a top view. The partition wall 7 forms a boundary between the main chamber 5 and the auxiliary chamber 6, and extends upward beyond the recess 8. The power feed line 13 connects a battery and the inverter 12, and supplies electric power from the battery to the inverter 12. The power feed line 13 is routed so as to pass through the inner side of the recess 8 and penetrate a portion of the partition wall 7 that is located above the recess 8.

[0048] As described above, by routing the power feed line 13 inside the recess 8, the space inside the recess 8 can be effectively utilized, and the space utilization efficiency around the vehicle drive device 1 can be improved. Further, since the power feed line 13 can be extended forward of the auxiliary chamber 6, electric power can be smoothly supplied to the inverter 12 even when there is no spatial margin behind the auxiliary chamber 6. Furthermore, interference between components located behind the auxiliary chamber 6 (such as a harness, a refrigerant pipe, and the like) and the power feed line 13 can be prevented. Accordingly, the vehicle mountability of the vehicle drive device 1 can be further improved.

[0049] (3) The above-described vehicle drive unit 1 comprises an inverter cover 4, a control connector 21, and a suspension cross 31. The inverter cover 4 closes the other end of the sub-compartment 6. The control connector 21 is provided on the inverter cover 4. A harness for controlling the operating state of the inverter 12 is connected to the control connector 21. The suspension cross 31 is positioned on the other side of the sub-compartment 6 and extends in the vehicle width direction. The control connector 21 is positioned above the suspension cross 31.

[0050] In this way, by positioning the control connector 21 above the suspension cross 31, the suspension cross 31 can protect the area below the control connector 21. This improves the protection of the control connector 21 from flying debris from the road surface. Furthermore, the suspension cross 31 can be brought closer to the vehicle drive unit 1, improving the efficiency of space utilization in the longitudinal direction of the vehicle. Therefore, the vehicle mountability of the vehicle drive unit 1 can be further improved.

[0051] (4) The above-described vehicle drive unit 1 is positioned on the opposite side from the sub-compartment 6, fixed to the vehicle's floor panel 32, and includes a floor cross 33 that extends in the vehicle width direction. The control connector 21 is extended diagonally downward so that it moves away from the floor cross 33 as it moves away from the outer surface of the inverter cover 4, for example. This prevents interference between the control connector 21 and the floor cross 33, and in particular prevents interference with the floor cross 33 when the vehicle drive unit 1 vibrates. It is preferable that the extension direction of the control connector 21 be set so that a predetermined distance is secured from both the suspension cross 31 and the floor cross 33. This makes it possible to more reliably prevent interference between the control connector 21 and the suspension cross 31 and the floor cross 33.

[0052] (5) The above-described vehicle drive unit 1 includes a refrigerant nipple 22 provided on the inverter cover 4, to which a refrigerant pipe for cooling the inverter 12 is connected. The refrigerant nipple 22 is positioned above the suspension cross 31. This allows the suspension cross 31 to protect the lower part of the refrigerant nipple 22, improving the protection of the refrigerant nipple 22 from flying stones from the road surface. In addition, the suspension cross 31 can be brought closer to the vehicle drive unit 1, improving the efficiency of space utilization in the longitudinal direction of the vehicle. Therefore, the vehicle mountability of the vehicle drive unit 1 can be further improved.

[0053] (6) The above-described vehicle drive unit 1 includes an inverter cover 4 and a terminal block 26 that close off the other end of the sub-chamber 6. The terminal block 26 is provided inside the sub-chamber 6 at the connection point between the motor-side three-phase wires 27 extending from each of the pair of motors 10 and the inverter-side three-phase wires 28 extending from the inverter 12. The inverter cover 4 has a service hole 23, a boss 24 and a bulge 19. The service hole 23 is formed at a position on the other side from the terminal block 26. The boss 24 is formed in a levee-like shape so as to surround the outer circumference of the service hole 23. The bulge 19 is formed by bulging the inner and outer surfaces of the inverter cover 4 toward the outside of the sub-chamber 6. The boss 24 is positioned to overlap with the bulge 19.

[0054] In this way, by overlapping (overlapping) the bulging portion 19 and the boss 24 on the inverter cover 4, the size of the inverter cover 4 can be made more compact compared to when the bulging portion 19 and the boss 24 are dispersed. This makes it easier to downsize the vehicle drive unit 1 and further improves the vehicle mountability of the vehicle drive unit 1.

[0055] (7) The above-described vehicle drive device 1 includes a flat plate-shaped cover 25 that is attached to the outer end surface 30 of the boss and closes the service hole 23. As shown in Figure 6(A), the outer end surface 30 of the boss is formed to be in the same plane as the outer surface 29 of the bulge. Alternatively, as shown in Figure 6(B), the outer end surface 30 of the boss is formed to protrude in a direction away from the sub-chamber 6 than the outer surface 29 of the bulge. This prevents interference between the cover 25 and the bulge 19 and allows the cover 25 to be easily attached.

[0056] [3. Others] The above embodiments are merely illustrative examples. Various modifications and applications of techniques not explicitly shown in the above embodiments are not excluded. Each configuration of the above embodiments can be modified in various ways without departing from their spirit. Furthermore, each configuration of the above embodiments can be selected or combined as necessary without departing from the spirit of the present invention. Similar effects and advantages as those of the above embodiments can be provided to a vehicle drive unit comprising at least a main case portion 51 and a sub-case portion 52.

[0057] For example, the arrangement and extension direction of the control connector 21 and refrigerant nipple 22 provided on the inverter cover 4 do not have to be in the positions and directions described above, and can be appropriately omitted depending on the type and model of the inverter 12. Also, the surrounding structure of the terminal block 26 (service hole 23, boss 24, bulge 19, cover 25, etc.) is not limited to the configuration described above. The method of routing the power supply line 13 described above is just one example of many methods, and it may be routed through other parts other than the recess 8. The center case 2 may be formed by combining multiple divided parts. In this case, the side cover 3 and inverter cover 4 can be omitted. The side cover 3 and inverter cover 4 may be formed integrally with any of the divided parts.

[0058] The wheels driven by the above-described vehicle drive unit 1 may be either rear wheels or front wheels. Furthermore, the above-described vehicle drive unit 1 is applicable to vehicles other than four-wheeled vehicles. In the above embodiment, one side corresponds to the front of the vehicle and the other side corresponds to the rear of the vehicle, but these correspondences can be reversed. The relationship between the vehicle drive unit 1 and the surrounding vehicle body structure is not limited to the relationship shown in the above embodiment. A suspension cross 31 or floor cross 33 does not necessarily have to be provided on the rear side of the vehicle drive unit 1.

[0059] This invention is applicable to the manufacturing industry of vehicle drive systems for propelling vehicles. Furthermore, it is applicable to the manufacturing industry of vehicles to which vehicle drive systems are applied.

[0060] 1. Vehicle drive unit 2. Center case 3. Side cover 4. Inverter cover 5. Main chamber 6. Sub-chamber 7. Bulkhead 8. Recess 10. Motor 11. Gear mechanism 12. Inverter 13. Power supply line 14. Wheel axle 15. Motor shaft 16. Base plate 17. Semiconductor module 18. Capacitor 19. Bulge 21. Control connector 22. Refrigerant nipple 23. Service hole 24. Boss 25. Cover 26. Terminal block 27. Motor side three-phase wire 28. Inverter side three-phase wire 29. Outer surface of bulge 30. Outer end surface of boss 31. Suspension cross 32. Floor panel 33. Floor cross 41. Stator 42. Rotor 51. Main case section 52. Sub-case section

Claims

1. A vehicle drive system comprising a pair of motors and an inverter for driving the left and right wheels of a vehicle, the vehicle drive system comprising: a main chamber for housing the pair of motors, the main chamber for supporting the pair of motors spaced apart from each other such that the motor shafts, which are the output shafts of the pair of motors, are arranged coaxially, and the main chamber for supporting the wheel shafts connected to the left and right wheels at a position on one side of the motor shafts when viewed from above; and a sub-chamber for housing the inverter, the sub-chamber for housing the main chamber and provided adjacent to the main chamber on the other side of the motor shafts when viewed from above.

2. The vehicle drive device according to claim 1, comprising: a recess on the upper surface of the main case portion, formed by recessing downward in the portion sandwiched between the pair of motors in a top view; a partition wall forming the boundary between the main chamber and the sub-chamber and extending above the recess; and a power supply line connecting the battery and the inverter and supplying power from the battery to the inverter, wherein the power supply line is routed to pass inside the recess and through the portion of the partition wall above the recess.

3. The vehicle drive device according to claim 1, comprising: an inverter cover that forms part of the sub-case portion and closes the other end of the sub-compartment; a control connector provided on the inverter cover to which a harness for controlling the operating state of the inverter is connected; and a suspension cross positioned in the other direction from the sub-compartment and extending in the vehicle width direction of the vehicle, wherein the control connector is positioned above the suspension cross.

4. The vehicle drive device according to claim 3, characterized in that it is positioned in the other direction from the sub-compartment, is fixed to the floor panel of the vehicle, and includes a floor cloth that extends in the vehicle width direction, and the control connector is extended diagonally downward so as it moves away from the outer surface of the inverter cover, it moves away from the floor cloth.

5. The vehicle drive device according to claim 3, further comprising a refrigerant nipple provided on the inverter cover, to which a refrigerant pipe for cooling the inverter is connected, wherein the refrigerant nipple is positioned above the suspension cross.

6. The vehicle drive device according to claim 1, comprising: an inverter cover that forms part of the sub-case portion and closes the other end of the sub-chamber; and a terminal block provided inside the sub-case portion at the connection point between the motor-side three-phase wires extending from each of the pair of motors and the inverter-side three-phase wires extending from the inverter, wherein the inverter cover has a service hole formed at a position in the other direction from the terminal block, a boss formed in the shape of a ridge surrounding the outer circumference of the service hole, and a bulge portion formed by bulging the inner and outer surfaces of the inverter cover toward the outside of the sub-chamber, and the boss is positioned to overlap with the bulge portion.

7. The vehicle drive device according to claim 6, comprising a flat plate-shaped cover attached to the outer end surface of the boss to close the service hole, wherein the outer end surface of the boss is formed to be in the same plane as the outer surface of the bulge, or the outer end surface of the boss is formed to protrude in a direction away from the sub-chamber than the outer surface of the bulge.

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