hybrid vehicle drivetrain

Abstract

To provide a drive device for a hybrid vehicle, capable of suppressing noise generation without increasing the number of components.SOLUTION: A case 18 of a drive device 90 includes: a "first case" that is fastened to an engine 12 and accommodates a first electric motor MG1, a power distribution mechanism 40, a second electric motor MG2, a driven gear mechanism 28, and a differential gear 34; and a "second case" (rear cover 18c) fastened so as to close an opening of the "first case" opposite to the engine 12. An on-vehicle unit MD that also serves as a vibration suppression member is disposed at a position overlapping a line segment VW connecting a first axis CL1 and a third axis CL3 on the "second case" (rear cover 18c). As a result, vibration of the rear cover 18c is reduced by mass m of the on-vehicle unit MD, so that noise generation can be suppressed without increasing the number of components.SELECTED DRAWING: Figure 4

Description

Technical Field

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

Background Art

[0002] A first electric motor and a power distribution mechanism having an output rotating member provided with a drive gear, which distributes and transmits the power from the engine to the first electric motor and the output rotating member, are arranged on a first axis. A driven gear mechanism having a driven gear meshing with the drive gear is arranged on a second axis. A second electric motor connected to the driven gear mechanism is arranged on a third axis. A differential gear connected to the driven gear mechanism is arranged on a fourth axis. A drive device for a hybrid vehicle in which the first electric motor, the power distribution mechanism, the second electric motor, the driven gear mechanism, and the differential gear are housed in a case is well known. For example, the hybrid drive device described in Patent Document 1 is such a device. In this Patent Document 1, in a hybrid drive device, an actuator of a parking lock mechanism is fastened to the outer surface of a case located on the side opposite to the side where the meshing portion of the drive gear and the driven gear is located with respect to the first axis via a bracket, thereby suppressing the generation of gear noise.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Incidentally, the noise in the drive unit is generated not only from the meshing portion between the drive gear and the driven gear, but also from vibrations caused by other gears, electric motors, etc., which vibrate the case of the drive unit. In the case configuration, flat and wide surfaces tend to have low rigidity and are prone to vibration, making them more susceptible to noise. When the case of the drive unit is composed of a first case fastened to the engine and housing the internal components of the drive unit, and a second case in the shape of a lid fastened to close the opening of the first case on the opposite side of the engine, the second case has a flat and wide surface shape, making it prone to noise. Furthermore, vibrations from the first and second electric motors propagate from the respective rotating shaft support portions of the first and second electric motors provided in the second case, causing large vibrations in the flat and wide surfaces located between the respective rotating shaft support portions, i.e., areas prone to vibration, thereby generating noise. To address this, there was a problem in that the number of parts increased due to the addition of mass dampers, soundproofing covers, etc.

[0005] Furthermore, when a power control unit for controlling the power of the electric motor is integrated into the drive unit as an integrated electromechanical device, the power control unit is positioned, for example, on top of the drive unit. In order to secure maintenance space for the power control unit, if the mounting surface for the vehicle body mounting member, which was conventionally provided on top of the drive unit, is provided on the second case, then vibrations from the vehicle body are transmitted to the second case via the mounting surface, which can lead to increased noise generation.

[0006] This invention was made against the above circumstances, and its objective is to provide a drive system for a hybrid vehicle that can suppress noise generation without increasing the number of parts. [Means for solving the problem]

[0007] The gist of the first invention is that (a) a first electric motor and a power distribution mechanism having an output rotating member provided with a drive gear, which distributes and transmits power from an engine to the first electric motor and the output rotating member, are arranged on a first axis, a driven gear mechanism having a driven gear that meshes with the drive gear is arranged on a second axis, a second electric motor connected to the driven gear mechanism is arranged on a third axis, and a differential gear connected to the driven gear mechanism is arranged on a fourth axis, and the first electric motor, the power distribution A drive system for a hybrid vehicle, comprising a mechanism, the second electric motor, the driven gear mechanism, and the differential gear, housed in a case, wherein (b) the case includes a first case fastened to the engine and housing the first electric motor, the power distribution mechanism, the second electric motor, the driven gear mechanism, and the differential gear, and a second case fastened to close the opening of the first case on the side opposite to the engine, and (c) a position on the second case that coincides with a line segment connecting the first axis and the third axis Furthermore, the intermediate position of the respective rotating shaft support portions of the first and second electric motors The solution involves placing an in-vehicle unit that also serves as a vibration suppression member. [Effects of the Invention]

[0008] According to the first invention, the case includes a first case fastened to the engine and housing the first electric motor, the power distribution mechanism, the second electric motor, the driven gear mechanism, and the differential gear, and a second case fastened to close the opening of the first case on the side opposite to the engine, wherein a position on the second case overlaps with the line segment connecting the first axis and the third axis. Furthermore, the intermediate position of the respective rotating shaft support portions of the first and second electric motors An in-vehicle unit that also functions as a vibration suppression member is placed there. As a result, in addition to the in-vehicle unit's original role, the vibrations of the second case that are transmitted from the first and second electric motors are reduced by the mass of the in-vehicle unit, thereby suppressing noise generation without increasing the number of parts. [Brief explanation of the drawing]

[0009] [Figure 1]This figure illustrates an example of a schematic configuration of a hybrid vehicle to which the present invention is applied. [Figure 2] This diagram illustrates an example of an electrical configuration related to the control of an electric motor. [Figure 3] This diagram illustrates an example of the schematic configuration of a drive unit. [Figure 4] This figure illustrates an example of the arrangement of an in-vehicle unit, which also serves as a vibration suppression member to which the present invention is applied, on a drive unit. [Figure 5] This figure illustrates an example of the arrangement of the in-vehicle unit shown in Figure 4, when a mounting surface for the vehicle body mounting member is provided. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. [Examples]

[0011] Figure 1 is a diagram illustrating an example of the schematic configuration of a hybrid vehicle (hereinafter referred to as "vehicle") 10 to which the present invention is applied. In Figure 1, the vehicle 10 is a hybrid vehicle equipped with an engine 12 that functions as a power source and a second electric motor MG2 that functions as an electric motor. The vehicle 10 also includes drive wheels 14, a power transmission device 16, and a first electric motor MG1.

[0012] The engine 12 is a known internal combustion engine. The drive wheels 14 are the left and right wheels of the vehicle 10 in the forward and backward directions. The power transmission device 16 is provided in the power transmission path between the engine 12 and the drive wheels 14, and in the power transmission path between the second electric motor MG2 and the drive wheels 14.

[0013] The first electric motor MG1 and the second electric motor MG2 are known rotating electric machines, each having the function of an engine that generates mechanical power from electric power and a function of a generator that generates electric power from mechanical power, and are so-called motor generators. The first electric motor MG1 and the second electric motor MG2 are housed in a non-rotatable case 18, which is a non-rotating member attached to the vehicle body.

[0014] The power transmission device 16 includes a damper 20, an input shaft 22, a transmission unit 24, a compound gear 26, a driven gear mechanism 28, a differential gear 34, a reduction gear 36, etc., within a case 18. The power transmission device 16 also includes a pair of drive shafts 38 connected to the differential gear 34. The driven gear mechanism 28 includes a driven gear 28a, a driven shaft 30, and a final gear 32, with the driven gear 28a and the final gear 32 fixed to the driven shaft 30 so as not to rotate relative to each other.

[0015] The damper 20 is connected to the crankshaft 12a of the engine 12. The input shaft 22 functions as the input rotating member of the transmission unit 24. The input shaft 22 is connected to the damper 20 and is connected to the crankshaft 12a via the damper 20, etc. The transmission unit 24 is connected to the input shaft 22. The compound gear 26 is the output rotating member of the transmission unit 24. The compound gear 26 has a drive gear 26a formed on a part of its outer circumference. The driven gear 28a meshes with the drive gear 26a. The final gear 32 has a smaller diameter than the driven gear 28a and meshes with the differential ring gear 34a. The reduction gear 36 has a smaller diameter than the driven gear 28a and meshes with the driven gear 28a. The rotor shaft of the second electric motor MG2 is connected to the reduction gear 36, and the second electric motor MG2 is connected so as to transmit power.

[0016] The power transmission device 16 configured in this way is suitably used in FF (front-engine, front-drive) or RR (rear-engine, rear-drive) vehicles. The power transmission device 16 transmits power output from the engine 12 to the driven gear mechanism 28 via the transmission unit 24. The power transmission device 16 also connects the second electric motor MG2 and the driven gear mechanism 28 via a reduction gear 36 to enable power transmission. Furthermore, the power transmission device 16 connects the driven gear mechanism 28 and the differential gear 34 to enable power transmission, and transmits the power transmitted to the differential gear 34 to the drive wheels 14 via a drive shaft 38, etc. The driven gear mechanism 28 is a transmission mechanism that transmits power from the second electric motor MG2 to the differential gear 34, and is a transmission mechanism that transmits power from the drive gear 26a to the differential gear 34. The differential gear 34 distributes power from the engine 12 and the second electric motor MG2 to the drive wheels 14. The drive shaft 38 transmits power from the differential gear 34 to the drive wheels 14. The second electric motor MG2 is connected to the drive wheels 14 in a manner that it can transmit power.

[0017] The transmission unit 24 comprises a first electric motor MG1 and a power distribution mechanism 40. The power distribution mechanism 40 is a known single-pinion type planetary gear system comprising a sun gear S, a carrier CA, and a ring gear R. The sun gear S is connected to the rotor shaft of the first electric motor MG1. In other words, the power distribution mechanism 40, which is part of the power transmission device 16, is connected to the first electric motor MG1 in a power-transmitting manner. The carrier CA is connected to the input shaft 22. In other words, the power distribution mechanism 40 is connected to the engine 12 in a power-transmitting manner via the input shaft 22, etc. The ring gear R is formed on a part of the inner circumferential surface of the compound gear 26 and is integrally connected to the drive gear 26a. In other words, the power distribution mechanism 40 is connected to the drive wheels 14 in a power-transmitting manner.

[0018] The power distribution mechanism 40 is a power distribution mechanism that mechanically divides the power of the engine 12 input to the carrier CA between the first electric motor MG1 and the drive gear 26a. The transmission unit 24 is a known electric transmission mechanism in which the power distribution state of the power distribution mechanism 40 is controlled by controlling the operating state of the first electric motor MG1.

[0019] The power transmission device 16 has a first axis CL1, a second axis CL2, a third axis CL3, and a fourth axis CL4. These four axes CL1, CL2, CL3, and CL4 are parallel to each other. The first axis CL1 is the axis of the input shaft 22 and the rotor shaft of the first electric motor MG1. That is, the first axis CL1 is the rotation axis of the first electric motor MG1. The first electric motor MG1 and the power distribution mechanism 40 are arranged on the first axis CL1. The second axis CL2 is the axis of the driven shaft 30, and the driven gear mechanism 28 is arranged on the second axis CL2. That is, the second axis CL2 is the rotation axis of the driven gear mechanism 28. The third axis CL3 is the axis of the rotor shaft of the second electric motor MG2. That is, the third axis CL3 is the rotation axis of the second electric motor MG2. The second electric motor MG2 and the reduction gear 36 are arranged on the third axis CL3. The fourth axis CL4 is the axis of the drive shaft 38 and the axis of the differential gear 34. That is, the fourth axis CL4 is the rotation axis of the drive shaft 38 and the differential gear 34. The differential gear 34 is arranged on the fourth axis CL4. The second axis CL2 and the fourth axis CL4 are the rotation axes of the power transmission device 16.

[0020] Case 18 includes a housing 18a, a case body 18b, and a rear cover 18c. The housing 18a has an engine block 12b of the engine 12 fastened to an open portion on the engine 12 side. The housing 18a and the case body 18b are integrally fastened by a fastener such as a bolt so that an open portion on the side of the housing 18a opposite to the engine 12 and an open portion on the engine 12 side of the case body 18b are aligned. The case body 18b and the rear cover 18c are integrally fastened by a fastener so that the rear cover 18c closes an open portion on the side of the case body 18b opposite to the engine 12. The case body 18b is a case including a partition wall (not shown) that partitions a gear chamber Rg that houses a power distribution mechanism 40, a driven gear mechanism 28, a differential gear 34, etc., and a motor chamber Rm that houses a first electric motor MG1 and a second electric motor MG2. The case body 18b and the housing 18a form the gear chamber Rg. The case body 18b and the rear cover 18c form the motor chamber Rm. Thus, the case 18 houses the first electric motor MG1, the second electric motor MG2, the power distribution mechanism 40, the driven gear mechanism 28, the differential gear 34, etc. The housing 18a and the case body 18b correspond to the "first case" in the present invention. Also, the rear cover 18c corresponds to the "second case" in the present invention.

[0021] FIG. 2 is a diagram for explaining an example of an electrical configuration related to control of the first electric motor MG1 and the second electric motor MG2. In FIG. 2, the vehicle 10 further includes a high-voltage battery 50, an accessory battery 52, a power control unit 54, etc.

[0022] The high-voltage battery 50 is a rechargeable DC power source, such as a nickel-metal hydride secondary battery or a lithium-ion battery. The high-voltage battery 50 is connected to the power control unit 54. Stored power from the high-voltage battery 50 is supplied to, for example, the second motor MG2 via the power control unit 54. Power from the power generation control of the first motor MG1 and power from the regenerative control of the second motor MG2 are also supplied to the high-voltage battery 50 via the power control unit 54. The high-voltage battery 50 corresponds to the "battery" in this invention.

[0023] The power control unit 54 includes a DC-DC converter 56, an electric motor control device 58, a boost converter 60, and an inverter 62. The power control unit 54 is a power control device that controls the power exchanged between the high-voltage battery 50 and the first electric motor MG1 and the second electric motor MG2, respectively.

[0024] The DC-DC converter 56 is connected to the high-voltage battery 50. The DC-DC converter 56 functions as a charging device that steps down the voltage of the high-voltage battery 50 to a voltage equivalent to that of the auxiliary battery 52 and charges the auxiliary battery 52. ​​The auxiliary battery 52 supplies power to operate the auxiliary equipment, motor control device 58, electronic control device 70 (described later), etc., provided in the vehicle 10.

[0025] The boost converter 60 includes reactors and switching elements (not shown). The boost converter 60 is a buck-boost circuit that has the function of boosting the voltage of the high-voltage battery 50 and supplying it to the inverter 62, and the function of stepping down the voltage converted to DC by the inverter 62 and supplying it to the high-voltage battery 50.

[0026] The inverter 62 includes an MG1 power module 64, an MG2 power module 66, and the like. The MG1 power module 64 is equipped with multiple transistors that can be switched on and off as switching elements to convert DC current to three-phase AC current, and constitutes a three-phase bridge circuit of U-phase, V-phase, and W-phase. The vehicle 10 is further equipped with a busbar 68, and the first motor MG1 is electrically connected to the MG1 power module 64 (i.e., the inverter 62) by the busbar 68. The busbar 68 is a power line that electrically connects the first motor MG1 and the power control unit 54, and includes multiple busbars 68u, 68v, and 68w. The multiple busbars 68u, 68v, and 68w are three power lines that carry U-phase, V-phase, and W-phase three-phase AC current. The MG2 power module 66 has the same configuration as the MG1 power module 64, so the description of the MG2 power module 66 is omitted. The first motor MG1 and the second motor MG2 are three-phase AC synchronous motors, each driven by an inverter 62.

[0027] The inverter 62 converts the DC current from the boost converter 60 into AC current to drive the first motor MG1 and the second motor MG2. The inverter 62 converts the AC current generated by the first motor MG1 using the power of the engine 12, and the AC current generated by the second motor MG2 using regenerative braking, into DC current. The inverter 62 supplies the AC current generated by the first motor MG1 as power to drive the second motor MG2, according to the driving conditions.

[0028] Vehicle 10 is further equipped with an electronic control unit 70, a communication line 72, and the like. The electronic control unit 70 transmits and receives signals to and from a DC-DC converter 56, an electric motor control unit 58, and the like via the communication line 72. The electronic control unit 70 performs various controls on vehicle 10 based on signals from, for example, sensors (not shown). The communication line 72 is, for example, a well-known CAN (Controller Area Network) communication line.

[0029] The motor control device 58 controls the boost converter 60 and inverter 62 based on commands from the electronic control device 70, thereby controlling the first motor MG1 and the second motor MG2. For example, the motor control device 58 converts the DC current from the high-voltage battery 50 into AC current used by the first motor MG1 and the second motor MG2, respectively. The motor control device 58 drives the first motor MG1 to ensure the amount of power generated necessary for supplying power to the second motor MG2 and charging the high-voltage battery 50. The motor control device 58 drives the second motor MG2 based on the output requirement value corresponding to the driver's requested torque. The motor control device 58 makes the second motor MG2 function as a generator according to the amount of regenerative braking required.

[0030] Figure 3 is a diagram illustrating an example of the schematic configuration of the drive unit 90. Figure 3 is a side view of the vehicle 10 from the left side. In Figure 3, the transaxle 92 and the power control unit 54 are housed in the same case 18 as the drive unit 90. The drive unit 90 is a device in which the transaxle 92 and the power control unit 54 are integrated, i.e., a mechatronic integrated device. The transaxle 92 is a drive unit that includes power transmission devices 16 (20, 28, 34, 36, 40, etc.), a first motor MG1, and a second motor MG2. Note that the vertical direction, forward / reverse direction, and vehicle width direction (see Figure 5) in the figure indicate the direction when mounted on the vehicle 10. The vehicle width direction is the axial direction of the first axle CL1, the second axle CL2, the third axle CL3, and the fourth axle CL4.

[0031] Case 18 further comprises a protective plate 18d in addition to the housing 18a, case body 18b, and rear cover 18c described above. The case body 18b has a bottom wall and side walls extending vertically upward from the outer peripheral edges of the front and rear of the bottom wall, and its upper vertical end is open. The protective plate 18d is a plate-shaped member that closes the vertical upper opening in the case body 18b. The case body 18b has a partition wall (not shown) inside, which divides the interior into two spaces: a lower space A, which is the space at the bottom vertically, and an upper space B, which is the space at the top vertically. In the case of the drive unit 90, which is an integrated electromechanical device, the housing 18a, case body 18b, and protective plate 18d correspond to the "first case" in the present invention.

[0032] When mounted on the vehicle 10, the transaxle 92 is housed in the lower space A of the case body 18b or in the housing 18a.

[0033] The power control unit 54 is housed in the upper space B of the case body 18b when mounted in the vehicle 10. The upper space B includes the surplus space B1 created by the arrangement of the first motor MG1 and the second motor MG2, and the uppermost space B2 above the second motor MG2 in the vertical direction. The length of the surplus space B1 in the forward and reverse direction is shorter than that of the uppermost space B2. When mounted in the vehicle 10, the power control unit 54 is positioned adjacent to the first motor MG1 in the vertical direction, above it.

[0034] The surplus space B1 houses components of the power control unit 54 that are relatively short in length and relatively easy to replace, such as the DC-DC converter 56 and the reactor (not shown) of the boost converter 60.

[0035] Referring to Figure 3, in the mounted state on the vehicle 10, the transaxle 92 is arranged such that the first axle CL1, second axle CL2, third axle CL3, and fourth axle CL4 are each parallel to the horizontal direction perpendicular to the forward and backward direction of the vehicle 10. Furthermore, in the mounted state on the vehicle 10, the positions of the first axle CL1, second axle CL2, third axle CL3, and fourth axle CL4 are arranged in the order of second motor MG2, driven shaft 30, first motor MG1, and differential gear 34 from top to bottom in the vertical direction, and in the order of first motor MG1, driven shaft 30, differential gear 34, and second motor MG2 from front to rear in the forward and backward direction. Focusing on the first motor MG1 and the second motor MG2, the transaxle 92, when mounted on the vehicle 10, is arranged vertically from top to bottom in the order of the third axis CL3 and the first axis CL1. This ensures that the inter-axis distances of the first axis CL1, the second axis CL2, the third axis CL3, and the fourth axis CL4 are appropriately maintained, while reducing the vertical size of the transaxle 92. As a result, the arrangement of the first motor MG1 and the second motor MG2 creates surplus space B1, and the uppermost space B2 is created vertically above the second motor MG2. The power control unit 54 is mounted in this upper space B (B1 + B2).

[0036] In its mounted state on the vehicle 10, the power control unit 54 is positioned vertically above the transaxle 92. In addition, in its mounted state on the vehicle 10, the lower vertical portion of the power control unit 54 is positioned so that it overlaps with the upper vertical portion of the transaxle 92, particularly the second motor MG2, when viewed horizontally, particularly in the forward and backward directions. Alternatively, in its mounted state on the vehicle 10, the lower vertical portion of the power control unit 54 is positioned vertically above the first motor MG1. The lower vertical portion of the power control unit 54 consists of components (e.g., a DC-DC converter 56, a reactor) housed in the surplus space B1 of the power control unit 54.

[0037] The power control unit 54 is mounted in the space created by the reduction in the vertical size of the transaxle 92, and space is created vertically above the drive unit 90.

[0038] Incidentally, the noise of the drive unit 90, which is the problem that the present invention aims to solve, is generated by vibrations caused by internal gears, the first electric motor MG1, the second electric motor MG2, etc., which cause the case 18 of the drive unit 90 to vibrate. In the case configuration, flat and wide surfaces tend to generate noise because they have low rigidity and are prone to vibration. When the case 18 is composed of a "first case" (housing 18a, case body 18b, protective plate 18d) that is fastened to the engine 12 and houses the internal components of the drive unit 90, and a lid-shaped "second case" (rear cover 18c) that is fastened to close the opening of the first case on the opposite side of the engine 12, the rear cover 18c has a flat and wide surface shape, making it prone to generating noise. Furthermore, vibrations from the first motor MG1 and the second motor MG2 are transmitted from the respective rotating shaft support parts of the first motor MG1 and the second motor MG2, which are located on the rear cover 18c. This causes large vibrations in the flat, wide areas located between the respective rotating shaft support parts, i.e., areas prone to vibration, thereby generating noise. To address this, the addition of mass dampers, soundproofing covers, etc., resulted in the problem of increasing the number of parts.

[0039] Therefore, in the drive unit 90 of this embodiment, as shown in Figure 4, an on-board unit MD, which also serves as a vibration suppression member and has mass m, is placed on the rear cover 18c between the respective rotating shaft support parts of the first motor MG1 and the second motor MG2, at the aforementioned location prone to vibration, thereby reducing vibration. In Figure 4, the on-board unit MD with mass m is positioned to overlap with the line segment VW connecting the intersection point V between the surface of the rear cover 18c and the first axis CL1, and the intersection point W between the surface of the rear cover 18c and the third axis CL3. In Figure 4, the line segment VW is shown as a dashed line. As a result, vibrations of the rear cover 18c that are propagated from the first motor MG1 and the second motor MG2 are reduced by the placement of the on-board unit MD with mass m.

[0040] The on-board unit MD may include, for example, an oil cooler. It may also include, for example, an electric oil pump. Alternatively, for example, a DC-DC converter 56 may be relocated from the power control unit 54 and placed in the unit MD. The on-board unit MD can be preferably mounted on the rear cover 18c by fastening with bolts or by fixing it via mounting brackets. The rear cover 18c may also be preferably formed to accommodate the on-board unit MD as an integrated unit.

[0041] Furthermore, as in this embodiment, when the power control unit 54 is positioned on top of the drive unit 90 as an integrated electromechanical device, the mounting surface MZ for the vehicle body mounting member, which was conventionally provided on top of the drive unit 90, is provided on the rear cover 18c in order to secure a maintenance area for the power control unit 54. In this case, however, vibrations from the vehicle body are transmitted to the rear cover 18c via the mounting surface MZ, which can lead to increased noise generation.

[0042] Figure 5 illustrates an example of the arrangement of the on-board unit MD when the rear cover 18c is provided with a mounting surface MZ for the vehicle body mounting member. In Figure 5, the rear cover 18c has the mounting surface MZ for the vehicle body mounting member located vertically above the aforementioned line segment VW (dash-dotted line). Due to the propagation of vehicle body vibrations from the mounting surface MZ, the area where the rear cover 18c is most susceptible to vibration is the area directly below the mounting surface MZ in the vertical direction, that is, the area between the double-dotted lines ZL1 and ZL2 shown in Figure 5. Therefore, the on-board unit MD, which also serves as a vibration suppression member with mass m, is positioned in the area directly below the mounting surface MZ in the vertical direction (the area between the double-dotted lines ZL1 and ZL2) and overlapping with the line segment VW. As a result, vibrations of the rear cover 18c that are transmitted from the first electric motor MG1 and the second electric motor MG2 and the vehicle body are reduced by the arrangement of the on-board unit MD having mass m.

[0043] As described above, according to this embodiment, the case 18 includes a "first case" (housing 18a, case body 18b, protective plate 18d) that is fastened to the engine 12 and houses the first electric motor MG1, power distribution mechanism 40, second electric motor MG2, driven gear mechanism 28, and differential gear 34, and a "second case" (rear cover 18c) that is fastened to close the opening of the "first case" on the side opposite to the engine 12. An on-board unit MD, which also serves as a vibration suppression member, is placed on the "second case" (rear cover 18c) at a position that overlaps with the line segment VW connecting the first axis CL1 and the third axis CL3. As a result, in addition to the original role of the on-board unit MD, the vibration of the rear cover 18c that is propagated from the first electric motor MG1 and the second electric motor MG2 is reduced by the mass m of the on-board unit MD, thereby suppressing noise generation without increasing the number of parts.

[0044] Furthermore, according to this embodiment, the "first case" (housing 18a, case body 18b, protective plate 18d) houses the power control unit 54. As a result, even in a drive unit 90 that integrates and incorporates the power control unit 54 as an integrated electromechanical device, noise generation can be suppressed without increasing the number of parts.

[0045] Furthermore, according to this embodiment, the "second case" (rear cover 18c) is provided with a mounting surface MZ for a vehicle body mounting member located vertically above the line segment VW, and an on-board unit MD, which also serves as a vibration suppression member, is positioned in the area directly below the mounting surface MZ in the vertical direction. As a result, in addition to the original role of the on-board unit MD, the vibrations of the rear cover 18c that are transmitted from the first motor MG1 and the second motor MG2 and the vehicle body are reduced by the mass m of the on-board unit MD, thereby suppressing noise generation without increasing the number of parts.

[0046] Although embodiments of the present invention have been described in detail above with reference to the drawings, the present invention is also applicable to other embodiments.

[0047] For example, in the embodiment described above, the power control unit 54 was built into the drive unit 90 as an integrated electromechanical device, but the power control unit 54 may be configured as a separate device.

[0048] It should be noted that the above-described embodiment is merely one example, and the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art. [Explanation of Symbols]

[0049] 10: Vehicle (Hybrid Vehicle) 12: Engine 18: Case 18a: Housing (First Case) 18b: Case Body (First Case) 18c: Rear Cover (Second Case) 18d: Protective Plate (First Case) 26: Compound Gear (Output Rotating Member) 26a: Drive Gear 28: Driven Gear Mechanism 28a: Driven Gear 34: Differential Gear 40: Power Distribution Mechanism 50: High-Voltage Battery (Battery) 54: Power Control Unit 90: Drive System CL1: First Axle CL2: Second Axle CL3: Third Axle CL4: Fourth Axle MD: Onboard Unit MG1: First Motor MG2: Second Motor MZ: Mounting Surface VW: Line Segment

Claims

1. A first electric motor and a power distribution mechanism having an output rotating member equipped with a drive gear, which distributes and transmits power from the engine to the first electric motor and the output rotating member, are arranged on the first axis. A driven gear mechanism having a driven gear that meshes with the drive gear is arranged on the second axis. The second electric motor, which is connected to the driven gear mechanism, is positioned on the third axis. A differential gear connected to the driven gear mechanism is positioned on the fourth axis. The first electric motor, the power distribution mechanism, the second electric motor, the driven gear mechanism, and the differential gear are housed in a case, in a drive system for a hybrid vehicle. The case comprises a first case fastened to the engine and housing the first electric motor, the power distribution mechanism, the second electric motor, the driven gear mechanism, and the differential gear, and a second case fastened to close the opening of the first case on the side opposite to the engine. An on-board unit, which also serves as a vibration suppression member, is positioned on the second case at a location that overlaps with the line segment connecting the first axis and the third axis, and at an intermediate position between the respective rotating shaft support portions of the first and second electric motors. A drive system for a hybrid vehicle characterized by the following features.

2. The first case further houses a power control unit that controls the power exchanged between the first motor, the second motor, and the battery. The drive system for a hybrid vehicle according to feature 1.

3. The second case has a mounting surface for the vehicle body mounting member located vertically above the line segment, and the vehicle-mounted unit, which also serves as the vibration suppression member, is positioned in the area directly below the mounting surface in the vertical direction. A drive system for a hybrid vehicle according to any one of claims 1 to 2.

Images