Vehicle Drive Unit

Abstract

A vehicle drive device (10) comprises left and right motors (1, 2) that drive left and right wheels of a vehicle, a gear box (3) sandwiched between the left and right motors (1, 2), and an inverter (4) disposed in a mounting space S above the left and right motors (1, 2) and the gear box (3). The gear box (3) forms a recessed portion (8) recessed downward together with left and right motor housings (11, 12). The inverter (4) has a flat-plate-shaped cover (15) which is mounted to a tray portion (16) that receives a capacitor (5) and a semiconductor module (6) and which covers the capacitor (5) and the semiconductor module (6) from above. The capacitor (5) is mounted to the lower surface of the cover (15) and disposed in the recessed portion (8). The semiconductor module (6) is mounted to the lower surface of the cover (15) and disposed at a position different from each of the capacitor (5) and the rotary axis (C) of the motors (1, 2) in a top view.

Description

[Technical field]

[0001] The present invention relates to a vehicle drive device that drives the left and right wheels of a vehicle using battery power. [Background technology]

[0002] Conventionally, there is known a vehicle drive device that drives the left and right wheels of a vehicle with two motors (electric motors). For example, a device has been proposed in which separate motors are connected to the left and right wheels so that the left and right wheels can be driven independently of each other. In such a vehicle drive device, a difference in rotation speed and torque can be generated between the left and right wheels by making the driving forces of the left and right motors different. This improves the vehicle's turning performance and the vehicle body stability during turning (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-184523 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology described in Patent Document 1, the inverter is installed on a partition wall that separates the accommodation space of the reducer from the accommodation space of the inverter. Therefore, excess space is likely to be generated above the inverter in the accommodation space of the inverter, and there is room for improvement in terms of compactness. In addition, the inverter includes various components such as a capacitor and a semiconductor module, but depending on the arrangement of these components, the inverter may not be formed compactly. For example, when the components of the inverter are arranged in a vertically stacked manner, there is a problem that the vertical dimension of the inverter is likely to be large. Therefore, there is a demand for the development of a vehicle drive device that can compactly mount an inverter in a limited space.

[0005] One of the objects of the present invention, which has been devised in light of the above-mentioned problems, is to provide a vehicle drive device in which an inverter can be mounted compactly. However, in addition to this object, another object of the present invention is to achieve effects derived from the configurations shown in the "Description of Embodiments" described later, which cannot be obtained by conventional techniques. [Means for solving the problem]

[0006] The disclosed vehicle drive device includes left and right motors having a rotating shaft extending in the left-right direction of the vehicle and arranged at a distance from each other in the left-right direction, driving left and right wheels of the vehicle, a gear box having a built-in gear mechanism amplifying the torque of the left and right motors and transmitting it to each of the left and right wheels, sandwiched between the left and right motors and forming a recess recessed downward together with each motor housing of the left and right motors, and an inverter arranged in a mounting space above the left and right motors and the gear box, and having a capacitor for smoothing electric power and a semiconductor module including a plurality of switching elements. The inverter has a tray portion that houses the capacitor and the semiconductor module, and a flat cover attached to the tray portion and covering the capacitor and the semiconductor module from above. The capacitor is attached to a lower surface of the cover and arranged in the recess, and the semiconductor module is attached to the lower surface of the cover and arranged at a position different from each of the capacitor and the rotating shaft when viewed from above. Effect of the Invention

[0007] According to the present invention, by adopting a layout in which the capacitor and the semiconductor module are hung from the cover, space can be effectively utilized, and therefore a vehicle drive device in which an inverter can be mounted compactly can be provided. [Brief description of the drawings]

[0008] [Figure 1] 1 is an exploded perspective view of a vehicle drive device according to an embodiment; [Diagram 2]2 is a cross-sectional view for explaining an internal structure of the vehicle drive device shown in FIG. [Diagram 3] FIG. 2 is a left side view of the vehicle drive device shown in FIG. [Figure 4] 2 is a top view for explaining the arrangement of components of an inverter provided in the vehicle drive device shown in FIG. [Diagram 5] FIG. 5 is a top view (corresponding to FIG. 4) for explaining a modified example of the arrangement of inverter components. [Figure 6] FIG. 5 is a top view (corresponding to FIG. 4) for explaining another modified example of the inverter component arrangement. [Figure 7] FIG. 5 is an exploded perspective view for explaining the internal structure of the inverter shown in FIG. 4, the view being upside down. [Figure 8] 5 is a top view for explaining a cooling passage of the inverter shown in FIG. 4. [Figure 9] FIG. 5 is a left side view of the inverter shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [1. Configuration] 1 to 4 and 7 to 9 are diagrams for explaining the configuration of a vehicle drive device 10 according to this application example (embodiment). In the drawings, front / rear, left / right, and up / down refer to directions defined with reference to the driver of the vehicle on which the vehicle drive device 10 is mounted. As shown in FIG. 1, the vehicle drive device 10 is provided with a left motor 1, a right motor 2, a gear box 3, and an inverter 4. The left and right motors 1 and 2 (left motor 1, right motor 2) are electric motors that receive power from a battery (not shown) mounted on the vehicle and drive the left and right wheels of the vehicle.

[0010] The left and right motors 1, 2 have a rotation axis C (in the drawings, the center of rotation of the rotation axis shown by the dashed line is marked with the symbol C) extending in the left-right direction (vehicle width direction), and are arranged coaxially and spaced apart from each other in the left-right direction. The left motor 1 is connected to a power transmission path that is connected to at least the left wheel axle. Similarly, the right motor 2 is connected to a power transmission path that is connected to at least the right wheel axle. In an electric vehicle or hybrid vehicle equipped with other drive motors or engines, the left and right motors 1, 2 function as yaw moment generating sources that generate turning force by increasing or decreasing at least the driving force or braking force of the left and right wheels. In an electric vehicle not equipped with other drive motors, the motors 1, 2 also function as a drive source for the vehicle in addition to the above functions.

[0011] In this embodiment, the left and right motors 1, 2 are configured similarly to each other. Each motor 1, 2 has a structure that incorporates electric motor elements such as a stator, rotor, and motor shaft. As shown in Fig. 2, these elements are housed in left and right motor housings 11, 12 (left motor housing 11, right motor housing 12) that form the exterior of each motor 1, 2 (the electric motor elements of each motor 1, 2 are housed inside). The motor housings 11, 12 are configured such that the bottoms of the bottomed cylindrical bodies face outward in the left-right direction, and end bells are attached to the openings on the center side in the left-right direction.

[0012] The stator has a structure in which a coil is wound around a laminated core made of, for example, laminated electromagnetic steel sheets coated with an insulating film, and is fixed to each of the motor housings 11, 12. The rotor is a cylindrical rotor in which a permanent magnet is inserted into a laminated core made of, for example, laminated electromagnetic steel sheets coated with an insulating film, and is loosely inserted inside the stator while being concentric with the central axis of the stator, and is fixed to the shaft-shaped motor shaft. By changing the frequency of the AC power applied to the stator, the rotation speed of the magnetic field inside the stator changes, and the angular speed of the rotor and the motor shaft changes. One end of the motor shaft is connected to the gear box 3. The left motor 1 is arranged on the left side of the gear box 3, and the right motor 2 is arranged on the right side of the gear box 3.

[0013] The gearbox 3 is a driving force transmission device that is sandwiched between left and right motor housings 11, 12. The gearbox 3 has a gearbox housing 13 that forms the exterior and a gear mechanism built into it. The gear mechanism amplifies the torque of the left motor 1 and the right motor 2 and transmits it to the left and right wheels. The gear mechanism also includes a mechanism (such as a differential gear mechanism or a planetary gear mechanism) for generating a torque difference between the left and right wheel axles.

[0014] The gearbox housing 13 of this embodiment is disposed offset downward with respect to the left and right motor housings 11, 12. Specifically, as shown in Fig. 3, the positional relationship between the left and right motor housings 11, 12 and the gearbox housing 13 is set so that the gearbox 3 is disposed in a position biased downward and forward (in the radial direction of the left and right motors 1, 2) in a side view with reference to the rotation axis C of the left and right motors 1, 2. With this layout, the gearbox 3 forms a recess 8 recessed downward together with the motor housings 11, 12. As shown in Figs. 2 and 3, the recess 8 is basin-shaped recessed downward between the left and right motor housings 11, 12.

[0015] The inverter 4 is a converter (DC-AC inverter) that converts between power of a DC circuit (DC power) and power of an AC circuit (AC power) on the motors 1 and 2 side. The inverter 4 has a function of converting DC power into AC power and supplying it to both the left and right motors 1 and 2. The inverter 4 is disposed in a mounting space S (indicated by a two-dot chain line in FIG. 2) above the left and right motors 1 and 2 and the gear box 3. The mounting space S is a space formed between the vehicle drive device 10 and the surrounding devices and the vehicle body at the position where the vehicle drive device 10 is mounted, and is T-shaped in front view including the recess 8 between the motor housings 11 and 12 and the space above the motor housings 11 and 12.

[0016] 3, in this embodiment, the upper ends of the motor housings 11, 12 are located directly above the rotation axis C of the motors 1, 2 (parts that overlap with the rotation axis C in a top view). For this reason, the part of the mounting space S above the motor housings 11, 12 (the space corresponding to the horizontal bar of the T) is smallest directly above the rotation axis C. In other words, the mounting space S is secured to be larger at a position shifted from the rotation axis C than at a position that overlaps with the rotation axis C in a top view.

[0017] 1, the inverter 4 has a capacitor 5 that smoothes power, and a semiconductor module 6 including a plurality of switching elements. The capacitor 5 and the semiconductor module 6 are built into an inverter case 14 that forms the exterior of the inverter 4. In this embodiment, a current sensor 7, which is one of the components of the inverter 4, is also built into the inverter case 14 together with the capacitor 5 and the semiconductor module 6.

[0018] The inverter case 14 is disposed in the mounting space S and fixed to the left and right motor housings 11, 12. The inverter case 14 is formed by combining a tray portion (inverter lower case) 16 that houses the capacitor 5 and the semiconductor module 6, and a flat cover (inverter upper case) 15 that covers the capacitor 5 and the semiconductor module 6 from above. The tray portion 16 in this embodiment is provided separately from the gear box 3 (gear box housing 13). However, the tray portion 16 may be provided integrally with the gear box 3 (as a part of the gear box housing 13).

[0019] Capacitor 5 is an electronic component having a larger thickness dimension (vertical dimension) than other components (semiconductor module 6 and current sensor 7) of inverter 4. In this embodiment, one capacitor 5 is used for both the left and right motors 1 and 2. In a current-controlled inverter, capacitor 5 is installed in the power supply line of AC power converted by the semiconductor module 6, and in a voltage-controlled inverter, capacitor 5 is installed on the input side of DC power. Capacitor 5 functions as a kind of filter, so to speak, and plays a role in stabilizing the current supplied to motors 1 and 2.

[0020] The semiconductor module 6 is a power module that has a three-phase bridge circuit including a plurality of switching elements and diodes formed on a substrate (electronic circuit substrate). DC power is converted into three-phase AC power 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 the switching elements.

[0021] The semiconductor module 6 of this embodiment includes left and right (pair) modules 6L, 6R (left module 6L, right module 6R) used for the left and right motors 1, 2, respectively. The left and right modules 6L, 6R are provided separately from each other. The left module 6L is a semiconductor module dedicated to the left motor 1. AC power generated by the left module 6L is supplied to the left motor 1. On the other hand, the right module 6R is a semiconductor module dedicated to the right motor 2. AC power generated by the right module 6R is supplied to the right motor 2. Similar to the semiconductor module 6, the current sensor 7 includes left and right (a pair) sensors 7L, 7R (left sensor 7L, right sensor 7R) used for the left and right motors 1, 2. The left and right sensors 7L, 7R are also provided separately from each other.

[0022] Regarding the arrangement of the inverter 4, at least the capacitor 5 having the largest thickness dimension is arranged in the recess 8 (inside the recess 8 or directly above the recess 8). Furthermore, the semiconductor module 6 is arranged in a position different from both the capacitor 5 and each rotation axis C when viewed from above. In addition, the current sensor 7 is arranged in a position different from all of the capacitor 5, the semiconductor module 6, and the rotation axis C when viewed from above. Therefore, when viewed from above, the capacitor 5 is located between the left and right motor housings 11, 12, and the semiconductor module 6 and the current sensor 7 are each positioned offset in the front-to-back and left-to-right directions with respect to the capacitor 5 and the rotation axis C, and do not overlap with the capacitor 5 and the rotation axis C.

[0023] 4, in this embodiment, the left and right modules 6L, 6R and the left and right sensors 7L, 7R are all arranged in the recess 8. That is, the inverter 4 in this embodiment is arranged entirely inside the recess 8 or directly above the recess 8. Inside the recess 8, the left and right modules 6L, 6R are arranged respectively in the front-to-rear direction (front and rear) with respect to the capacitor 5, and the left and right sensors 7L, 7R are also arranged respectively in the front-to-rear direction (front and rear) with respect to the capacitor 5.

[0024] In this embodiment, the left module 6L and the left sensor 7L dedicated to the left motor 1 are disposed behind the capacitor 5, and the right module 6R and the right sensor 7R dedicated to the right motor 2 are disposed in front of the capacitor 5. The left sensor 7L is disposed to the right of the left module 6L, and the right sensor 7R is disposed to the left of the right module 6R. However, the arrangement of the semiconductor module 6 and the current sensor 7 is not limited to this. For example, the positions of the left and right modules 6L, 6R may be interchanged with each other, and the positions of the left and right sensors 7L, 7R may be interchanged with each other.

[0025] 5 and 6 show modified examples of the arrangement of the semiconductor module 6 and the current sensor 7. In these modified examples, the position of the capacitor 5 is the same as in FIG. As shown in FIG. 5, the left and right modules 6L, 6R and the left and right sensors 7L, 7R may be disposed in either the front or rear of the capacitor 5 in the forward or rearward direction. When the gear box 3 is disposed offset forward with respect to the motor housings 11, 12 as described above, the mounting space S is secured to be larger in front of the rotation axis C than behind it. For this reason, in the modified example shown in FIG. 5, both the left and right modules 6L, 6R are disposed in front of the capacitor 5. Note that in a configuration in which the gear box 3 is disposed offset backward with respect to the motor housings 11, 12, the mounting space S behind the rotation axis C becomes wider, so that the left and right modules 6L, 6R and the left and right sensors 7L, 7R may be disposed behind the capacitor 5, in contrast to the arrangement shown in FIG. 5.

[0026] Alternatively, as shown in FIG. 6, the left module 6L and the left sensor 7L may be disposed on the left side of the capacitor 5, and the right module 6R and the right sensor 7R may be disposed on the right side of the capacitor 5. In this case, it is preferable that one of the left and right modules 6L, 6R is disposed forward of the rotation axis C, and the other is disposed rearward of the rotation axis C. Similarly, it is preferable that one of the left and right sensors 7L, 7R is disposed forward of the rotation axis C, and the other is disposed rearward of the rotation axis C. It is more preferable that the left module 6L and the left sensor 7L are disposed separately in the front-rear direction (front and rear) with respect to the rotation axis C of the left motor 1, and the right module 6R and the right sensor 7R are disposed separately in the front-rear direction (front and rear) with respect to the rotation axis C of the right motor 2.

[0027] In the modified example shown in Fig. 6, the left module 6L is disposed rearward of the rotation axis C of the left motor 1, and the left sensor 7L is disposed forward of the rotation axis C of the left motor 1. In addition, the right module 6R is disposed forward of the rotation axis C of the right motor 2, and the right sensor 7R is disposed rearward of the rotation axis C of the right motor 2. Thus, in the modified example shown in Fig. 6, the front and rear positions of the semiconductor module 6 and the current sensor 7 are swapped with each other on the left and right of the capacitor 5 (diagonal arrangement).

[0028] The inverter case 14 has a shape corresponding to the arrangement of the capacitor 5, the semiconductor module 6, etc. so as to be able to house the components of the inverter 4. For example, in the modified example shown in Fig. 5, it is T-shaped in top view, and in the modified example shown in Fig. 6, it is substantially square in top view. As shown in Figs. 1 to 4, in this embodiment, since both the capacitor 5 and the semiconductor module 6 are arranged in the recess 8, the inverter case 14 has a shape corresponding to the shape of the recess 8 in top view, that is, a substantially rectangular shape that is long in the front-rear direction in top view.

[0029] 2 and 7, the capacitor 5, the semiconductor module 6, and the current sensor 7 are all attached to a lower surface 17 of the cover 15 (hereinafter also referred to as "the cover lower surface 17"). The cover lower surface 17 is an inner surface that faces the tray part 16 side (downward) when the cover 15 is attached to the tray part 16. The capacitor 5, the semiconductor module 6, and the current sensor 7 attached to the cover lower surface 17 are housed in the tray part 16 in a state of being suspended from the cover lower surface 17.

[0030] 1 and 7, the cover 15 of this embodiment has a flat plate portion 34 attached to the periphery of the tray portion 16, a protrusion 31 formed in a protruding shape extending upward from the flat plate portion 34 to accommodate the capacitor 5, and a cooling passage 30 through which a coolant for cooling the semiconductor module 6 flows. The protrusion 31 is shaped to bulge upward in the center (center in the front-to-rear direction) of the cover 15. The capacitor 5 is fixed to a position on the cover underside 17 corresponding to the protrusion 31 so as to be suspended from the protrusion 31.

[0031] The cover 15 of this embodiment further has two bulging portions 32, 33 each bulging upward in the front-rear direction of the protrusion 31. Each of the bulging portions 32, 33 is convex with a smaller vertical dimension (amount of bulging from the flat plate portion 34) than the protrusion 31. The two bulging portions 32, 33 each have a built-in cooling passage (not shown) for cooling the left and right modules 6L, 6R, respectively, and the left and right modules 6L, 6R are disposed directly below the bulging portions 32, 33. The left and right modules 6L, 6R are fixed to the cover lower surface 17 at positions corresponding to the bulging portions 32, 33, respectively, so as to be suspended from the flat plate portion 34. The left and right sensors 7L, 7R are attached to the underside 17 of the cover so as to be suspended from the cover 15 at positions adjacent to the left and right modules 6L, 6R, respectively.

[0032] 1 and 8, the cooling passage 30 is integrally formed with the cover 15 and has a tubular shape bulging upward from the flat plate portion 34. A hollow portion that serves as a flow path for the coolant is provided inside the cooling passage 30. The cooling passage 30 of this embodiment includes a front supply passage 35 and a front discharge passage 36 connected to the cooling passage in the front bulging portion 33, a rear supply passage 37 and a rear discharge passage 38 connected to the cooling passage in the rear bulging portion 32, and a connection passage 39 that connects the front supply passage 35 and the rear discharge passage 38 together.

[0033] The two supply paths 35, 37 and the two discharge paths 36, 38 all extend along the left-right direction. The front supply path 35 extends leftward from the front bulge 33, and the front discharge path 36 extends rightward from the front bulge 33. Meanwhile, the rear supply path 37 extends rightward from the rear bulge 32, and the rear discharge path 38 extends leftward from the rear bulge 32. The connection path 39 is disposed to the left of the convex portion 31 and extends along the front-rear direction.

[0034] The cooling passage 30 is formed in the flat plate portion 34 so as to overlap the convex portion 31 when viewed from a direction perpendicular to the up-down direction. In other words, the up-down position of the cooling passage 30 is set to coincide with (or be included in) the up-down position of the convex portion 31. In this embodiment, the cooling passage 30 is formed so that each of the two supply paths 35, 37 and the two discharge paths 36, 38 overlaps with the convex portion 31 when viewed from the front-rear direction, and the connection path 39 overlaps with the convex portion 31 when viewed from the left-right direction.

[0035] The coolant supplied to the rear supply path 37 from outside the inverter 4 is supplied from the rear supply path 37 to a cooling path in the rear bulging portion 32, cools the right module 6R via a heat sink not shown, and is then discharged to the rear discharge path 38. This coolant is then supplied to the front supply path 35 through a connection path 39. The coolant supplied to the front supply path 35 is then supplied from the front supply path 35 to a cooling path in the front bulging portion 33, cools the left module 6L via a heat sink not shown, and is then discharged to the front discharge path 36. The coolant is then discharged from the front discharge path 36 to the outside of the inverter 4.

[0036] In this manner, the cooling passage 30 of the present embodiment has a structure in which the rear discharge passage 38 and the front supply passage 35 are connected in series by the connection passage 39. Alternatively, the cooling passage 30 may have a structure in which the front supply passage 35 and the front discharge passage 36 connected to the cooling passage in the front bulging portion 33, and the rear supply passage 37 and the rear discharge passage 38 connected to the cooling passage in the rear bulging portion 32 are connected in parallel. Also, instead of the connection passage 39 integrally molded with the cover 15, the front supply passage 35 and the rear discharge passage 38 may be connected to each other by a tube (not shown) formed separately from the cover 15.

[0037] As shown in Fig. 7, the inverter 4 of this embodiment has terminals 9 bent in an L-shape downward from the cover lower surface 17 side. Three terminals 9 are provided at a position adjacent to the left sensor 7L, and three terminals 9 are provided at a position adjacent to the right sensor 7R. The three terminals 9 adjacent to the left sensor 7L are connected to a bus bar 20 extending from the left motor 1 (one of the left and right motors 1 and 2) and form a three-phase AC power supply line for the left motor 1. Similarly, the three terminals 9 adjacent to the right sensor 7R are connected to a bus bar 20 extending from the right motor 2 (one of the left and right motors 1 and 2) and form a three-phase AC power supply line for the right motor 2. Each terminal 9 has a base 9a extending in the left-right direction from the current sensor 7 side, and a connection portion 9b extending downward (bent at 90 degrees) from the base 9a. The connection portion 9b is disposed in a vertical orientation and is connected to a bus bar 20 extending upward from each of the motors 1 and 2.

[0038] 9, the tray portion 16 is formed in a container shape having an internal space capable of accommodating the capacitors 5 and the semiconductor modules 6 suspended from the cover underside 17. The side surface portion 18 forming the internal space of the tray portion 16 is provided with an access hole 22 for connecting the terminals 9 and the busbars 20, and a connector 23 to which wiring is connected from the outside. In this embodiment, the access hole 22 and the connector 23 are both formed in the left surface portion 18L and the right surface portion 18R (see FIG. 2) of the side surface portion 18 facing in the left-right direction.

[0039] The working hole 22 is provided through a front part of the left side portion 18L and a rear part of the right side portion 18R so as to correspond to the position of the terminal 9. The working hole 22 is an opening for inserting a tool when tightening the fastener 21 provided at the connection portion between the terminal 9 and the bus bar 20. In this embodiment, a rectangular working hole 22 is illustrated as an example. However, the shape of the working hole 22 is not particularly limited. Connection portion 9b of terminal 9 is disposed adjacent to working hole 22 in the internal space of tray portion 16. Bus bar 20 is passed through a bottom hole (not shown) that penetrates bottom surface portion 19 of tray portion 16, and then disposed adjacent to working hole 22 in the internal space of tray portion 16 and overlapped on connection portion 9b of terminal 9. Connection portion 9b of terminal 9 and bus bar 20 are fastened to each other by fastener 21 in the internal space of tray portion 16 using a tool inserted through working hole 22.

[0040] The connector 23 is an electric component for connecting, for example, wiring for low-voltage signals. In this embodiment, two connectors 23 are provided at each of the rear of the left side portion 18L and the front of the right side portion 18R. Each connector 23 has an elongated shape, and its longitudinal direction D is inclined with respect to both the front-rear direction and the up-down direction. Note that the specific arrangement and number of the connectors 23 are not limited to those shown here. The connectors 23 may be provided on the side portion 18 other than the left side portion 18L and the right side portion 18R, or may be omitted from the tray portion 16.

[0041] [2. Actions and Effects] (1) As shown in Fig. 4, in the above-described inverter 4, the capacitor 5 is attached to the cover underside 17 and disposed in the recess 8, and the semiconductor module 6 is attached to the cover underside 17 and disposed in a position different from the capacitor 5 and the rotating shaft C in a top view. In this way, by disposing the capacitor 5, which has the largest thickness dimension among the components of the inverter 4, in the recess 8, the capacitor 5 can be mounted compactly while effectively utilizing the recess 8 (the space between the motors 1 and 2). In addition, since the semiconductor module 6 does not overlap with the capacitor 5 and the rotating shaft C in a top view, the vertical dimension of the inverter 4 can be made compact.

[0042] Furthermore, by adopting a "hanging layout" in which both the capacitor 5 and the semiconductor module 6 are attached to the underside 17 of the cover, space can be effectively utilized, and the base plate can be omitted compared to a structure in which the capacitor 5 and the semiconductor module 6 are attached to a base plate separate from the cover 15. In other words, since the cover 15 can also serve the function of the base plate, the number of parts can be reduced and further space saving can be achieved. Therefore, according to the vehicle drive device 10, the inverter 4 can be compactly mounted in the limited mounting space S. Therefore, the vehicle drive device 10 can be made more compact.

[0043] In this embodiment, the current sensor 7 is also attached to the cover underside 17 and is disposed at a different position from the capacitor 5, the semiconductor module 6, and the rotation shaft C when viewed from above. In this way, the current sensor 7, which is one of the components of the inverter 4, does not overlap with the capacitor 5, the semiconductor module 6, and the rotation shaft C when viewed from above, thereby making it possible to further compact the vertical dimension of the inverter 4. Also, by attaching the current sensor 7 to the cover underside 17 in addition to the capacitor 5 and the semiconductor module 6 to form a "hanging layout," it is possible to omit the base plate while effectively utilizing the space as described above, thereby achieving further space saving.

[0044] (2) The left and right modules 6L, 6R are both disposed in the recess 8, and are disposed in the front-rear direction with respect to the capacitor 5. In this way, by disposing the capacitor 5, which is a component of the inverter 4, and the left and right modules 6L, 6R, all in the recess 8, the vertical dimension of the vehicle drive device 10 can be made more compact. In addition, by disposing the capacitor 5 between the left and right modules 6L, 6R, each unit of the left and right motors 1, 2 (assemblies including the motor housings 11, 12 and the semiconductor modules 6L, 6R, etc., and wiring from the motors 1, 2) can be standardized. This contributes to simplifying the assembly work of the vehicle drive device 10 and reducing costs. Furthermore, in this embodiment, since the inverter 4 is entirely disposed in the recess 8, the vertical dimension of the vehicle drive device 10 can be made even more compact.

[0045] (3) When the gearbox 3 is disposed offset downward and forward with respect to the left and right motor housings 11, 12, a large mounting space S is secured in front of the rotation axis C of the motors 1, 2. For this reason, in the modified example shown in FIG. 5, both the left and right modules 6L, 6R are disposed forward of the capacitor 5. In this way, by setting the arrangement of the left and right modules 6L, 6R according to the offset direction of the gearbox 3 with respect to the motor housings 11, 12, the mounting space S can be more effectively utilized while improving the ease of arrangement (freedom of posture) of the left and right modules 6L, 6R. In addition, if components other than the semiconductor module 6 (e.g., the current sensor 7) are also disposed in front of the capacitor 5 in the inverter 4, there is no need to arrange components behind the capacitor 5, which contributes to miniaturization of the rear portion.

[0046] When the gearbox 3 is disposed offset downward and rearward with respect to the motor housings 11, 12, a large mounting space S is secured behind the rotation axes C of the motors 1, 2. Therefore, in this case, by disposing both the left and right modules 6L, 6R rearward with respect to the capacitor 5 (a disposition that is the reverse of the modified example shown in FIG. 5), the same actions and effects as those described above can be obtained.

[0047] (4) Meanwhile, in the modified example shown in FIG. 6, the left module 6L is disposed on the left side of the capacitor 5, and the right module 6R is disposed on the right side of the capacitor 5. In this way, by disposing the left module 6L used in the left motor 1 on the left side of the capacitor 5, the left module 6L can be unitized (assembled) with the left motor 1. Similarly, by disposing the right module 6R used in the right motor 2 on the right side of the capacitor 5, the right module 6R can be unitized (assembled) with the right motor 2. Furthermore, commonizing the units of the left and right motors 1, 2 contributes to simplifying the assembly work of the vehicle drive device 10 and reducing costs.

[0048] 6, the left module 6L and the left sensor 7L are disposed in the front-rear direction with respect to the rotation axis C of the left motor 1, and the right module 6R and the right sensor 7R are disposed in the front-rear direction with respect to the rotation axis C of the right motor 2. By distributing the semiconductor module 6 and the current sensor 7 in this manner, it becomes easy to avoid interference between the components.

[0049] In addition, in the modified example shown in FIG. 6, the front and rear positions of the semiconductor module 6 and the current sensor 7 are swapped on the left and right sides of the capacitor 5. Specifically, on the left side of the capacitor 5 (the unit of the left motor 1), the left sensor 7L is disposed in front of the left module 6L (either in the front or rear direction), and on the right side of the capacitor 5 (the unit of the right motor 2), the right sensor 7R is disposed behind the right module 6R (either in the front or rear direction). In this way, by disposing the semiconductor module 6 and the current sensor 7 symmetrically in the front and rear in the units of the left and right motors 1 and 2, the units of the left and right motors 1 and 2 can be made common. This contributes to simplifying the assembly work of the vehicle drive device 10 and reducing costs.

[0050] 1 and 7, the cover 15 is provided with a protrusion 31 that is formed in a convex shape extending upward from the flat plate portion 34 and that accommodates the capacitor 5. In this manner, by locally protruding the protrusion 31 that accommodates the capacitor 5 having a large thickness from the flat plate portion 34, it is possible to ensure the accommodation of the capacitor 5 while avoiding an increase in the overall size of the cover 15.

[0051] 1 and 8, the flat plate portion 34 of the cover 15 is formed with a cooling passage 30 for cooling the semiconductor module 6 so as to overlap with the protrusion 31 when viewed from a direction perpendicular to the vertical direction. By arranging the cooling passage 30 at the same position (height position) as the protrusion 31 in the vertical direction in this manner, it is possible to effectively utilize the dead space adjacent to the protrusion 31 in the direction perpendicular to the vertical direction. Therefore, it is possible to ensure the cooling performance of the semiconductor module 6 while making the vertical dimension of the vehicle drive device 10 more compact.

[0052] (7) Since the connector 23 to which wiring is connected from outside is provided on the side surface 18 of the tray portion 16, the shape of the cover 15 can be simplified compared to when the connector 23 is provided on the cover 15.

[0053] (8) The connector 23 has an elongated shape, is provided on the side surface portions 18 (left surface portion 18L and right surface portion 18R) facing the left-right direction, and has a longitudinal direction D inclined with respect to the front-rear direction. By providing the connector 23 in such an inclined position, the longitudinal dimension of the tray portion 16 can be reduced compared to a horizontal position in which the longitudinal direction D coincides with the front-rear direction. This allows the inverter 4 to be made even more compact in the front-rear direction. This contributes to further miniaturization of the vehicle drive device 10. In addition, since the longitudinal direction D of the connector 23 in this embodiment is also inclined with respect to the vertical direction, the vertical dimension of the tray portion 16 can also be reduced compared to the case where the connector 23 is in an upright position in which the longitudinal direction D coincides with the vertical direction.

[0054] (9) The inverter 4 is provided with a terminal 9 that is bent downward from the cover lower surface 17 side into an L-shape and is connected to a bus bar 20 extending from one of the left and right motors 1, 2. By bending the terminal 9 downward in this way to meet the bus bar 20, the connection structure between the terminal 9 and the bus bar 20 can be made more compact than when the terminal 9 is not bent downward. This allows the inverter 4 to be made even more compact, which contributes to further miniaturization of the vehicle drive device 10.

[0055] [3. Modifications] The above embodiment and modified examples are merely examples, and are not intended to exclude the application of various modifications and techniques not explicitly stated in the embodiment and modified examples. Each configuration of the embodiment and modified examples can be modified in various ways without departing from the spirit of the embodiment and modified examples. Furthermore, each configuration of the embodiment and modified examples can be selected or appropriately combined as necessary.

[0056] For example, in the above-mentioned embodiment, the vehicle drive device 10 is illustrated in which the gearbox 3 is disposed at a position biased downward and forward in side view with respect to the rotation axis C of the motors 1, 2, but the gearbox 3 may be offset downward and backward. At least, by offsetting the gearbox housing 13 downward with respect to the left and right motor housings 11, 12, it becomes easy to arrange the inverter case 14 using the recess 8, and it becomes easy to accommodate the inverter 4 compactly in the mounting space S. Therefore, it is possible to obtain the same functions and effects as the above-mentioned embodiment.

[0057] The left and right modules 6L and 6R may be integrated together. That is, the semiconductor module 6 may be provided in common for the left and right motors 1 and 2, similar to the capacitor 5. The above-mentioned shape of the cover 15 is an example. The cover 15 may be formed in a flat plate shape without the protrusions 31 and the bulges 32 and 33, or the cooling passage 30 may be omitted by forming the cooling passage separately from the cover 15. [Explanation of symbols]

[0058] 1 Left Motor 2 Right Motor 3 Gearbox 4 Inverter 5. Capacitor 6 Semiconductor Module 6L Left module 6R Right module 8 Recess 9 Terminals 10 Vehicle drive unit 11 Left motor housing 12 Right motor housing 15 Cover 16 Tray section 17 Underside of cover 18 Side part 20 Busbar 23 Connector 30 Cooling passage 31 Convex 34 Flat plate part C Rotational Axis D Longitudinal direction S Loading space

Claims

1. left and right motors each having a rotation shaft extending in a left-right direction of the vehicle and spaced apart from each other in the left-right direction, the left and right motors driving left and right wheels of the vehicle; a gear box that incorporates a gear mechanism that amplifies the torque of the left and right motors and transmits the torque to each of the left and right wheels, the gear box being sandwiched between the left and right motors and forming a recess that is recessed downward together with each motor housing of the left and right motors; an inverter disposed in a mounting space above the left and right motors and the gear box, the inverter including a capacitor for smoothing electric power and a semiconductor module including a plurality of switching elements; the inverter includes a tray portion that houses the capacitor and the semiconductor module, and a flat cover that is attached to the tray portion and covers the capacitor and the semiconductor module from above, the capacitor is attached to the lower surface of the cover and disposed in the recess; The semiconductor module is attached to the lower surface of the cover and is disposed at a position different from each of the capacitor and the rotating shaft when viewed from above. A vehicle drive device comprising:

2. the semiconductor module includes left and right modules used for the left and right motors, respectively; The left and right modules are both disposed in the recess, and are disposed in the front-rear direction with respect to the capacitor.

2. The vehicle drive system according to claim 1, wherein:

3. the semiconductor module includes left and right modules used for the left and right motors, respectively; The gear box is disposed to be offset downwardly and in either the front-rear direction with respect to the left and right motor housings, The left and right modules are both disposed on either one side in the front-rear direction with respect to the capacitor.

2. The vehicle drive system according to claim 1, wherein:

4. the semiconductor module includes left and right modules used for the left and right motors, respectively; The left motor is disposed on the left side of the gear box, and the right motor is disposed on the right side of the gear box, The left module is disposed on the left side of the capacitor, and the right module is disposed on the right side of the capacitor.

2. The vehicle drive system according to claim 1, wherein:

5. The cover has a flat plate portion attached to the periphery of the tray portion, and a protrusion formed in a protruding shape extending upward from the flat plate portion and accommodating the capacitor.

2. The vehicle drive system according to claim 1, wherein:

6. The cover has a cooling passage formed on the flat plate portion so as to overlap the protrusion when viewed from a direction perpendicular to the up-down direction, and through which a coolant for cooling the semiconductor module flows.

6. The vehicle drive device according to claim 5 .

7. The tray portion is provided separately from the gear box, A connector for connecting wiring from the outside is provided on a side surface that defines the internal space of the tray.

2. The vehicle drive system according to claim 1, wherein:

8. The connector has an elongated shape, is provided on the side surface facing the left-right direction, and has a longitudinal direction inclined with respect to the front-rear direction.

8. The vehicle drive device according to claim 7,

9. The inverter is bent downward from the lower surface side into an L-shape and has a terminal connected to a bus bar extending from one of the left and right motors.

2. The vehicle drive system according to claim 1, wherein:

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