Vehicle drive device

Abstract

The present invention provides a vehicle drive device capable of suppressing an increase in the size of a drive unit when viewed from the direction of the axis of rotation of an input / output shaft of the drive unit, and suppressing an increase in the cost of a motor. (a) An engine, a first motor, a second motor, and a front drive shaft are respectively connected to a carrier, a sun gear, and a ring gear of the planetary gear device, (b) the second motor is disposed on the opposite side of the engine when viewed from the planetary gear device on a first axis, (c) the front drive shaft is connected to the carrier via an output shaft and a gear pair on a second axis, and (c) the carrier is connected to the sun gear. (d) The first motor is disposed on the engine side when viewed from the planetary gear device on the third axis and is connected to the carrier via the gear pair, and (e) the second axis is located at a position overlapping the first motor when viewed from the first axis direction.

Description

Technical Field

[0001] The present invention relates to a vehicle drive device comprising an engine, a drive unit and a drive shaft, wherein the drive unit includes a first electric motor, a second electric motor and a planetary gear assembly having three rotating elements, and the drive shaft drives one of the front wheels and the rear wheels. Background Technology

[0002] A vehicle drive system is known, comprising: an engine; and a drive unit including an electric motor MG1, an electric motor MG2, and a differential mechanism having three rotating elements. For example, the vehicle drive system described in Patent Document 1 is such a system. For example, in such a vehicle drive system, when the engine is configured longitudinally, as disclosed in Patent Document 1, the differential mechanism is typically a planetary gear unit. Furthermore, by arranging the electric motors MG1 and MG2 and the planetary gear unit coaxially, the size of the drive unit when viewed from the direction of the rotation axis of the input / output shaft of the drive unit can be reduced.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2017-178299 Summary of the Invention However, when the electric motors MG1 and MG2 and the planetary gear unit are arranged coaxially, it is necessary to insert other rotating shafts inside the rotating shaft connecting the electric motor MG1 and the planetary gear unit, or inside the rotating shaft connecting the electric motor MG2 and the planetary gear unit. This results in an increase in the size of the electric motors MG1 and MG2, leading to increased motor costs. Therefore, it is desirable to suppress the increase in the size of the drive unit when viewed from the rotational axis of the input / output shaft of the drive unit, and to suppress the increase in motor costs caused by the increased size of the electric motors.

[0004] The present invention was made against the background of the above circumstances, and its object is to provide a vehicle drive device that can suppress the increase in size of the drive unit when viewed from the rotation axis direction of the input and output shafts of the drive unit, and suppress the increase in the cost of the electric motor.

[0005] The essence of this invention is a vehicle drive system comprising: an engine; a first drive unit including a first electric motor, a second electric motor, and a planetary gear assembly having three rotating elements; and a first drive shaft driving one of a front wheel and a rear wheel. In the vehicle drive system, (a) the planetary gear assembly has three rotating elements—a first rotating element, a second rotating element, and a third rotating element—and functions as a differential mechanism; (b) the engine and the first electric motor are connected to the first rotating element, the second electric motor is connected to the second rotating element, and the first drive shaft is connected to the third rotating element; (c) the second electric motor drives the first drive shaft from the rotation axis of the planetary gear assembly, i.e., the first axis. (d) The first drive shaft is connected to the third rotating component without passing through the interior of the connecting shaft connecting the second motor and the second rotating component, via an output shaft with a rotation axis of a second axis parallel to the first axis and a first power transmission mechanism that transmits power between the output shaft and the third rotating component. (e) The first motor is located on the engine side when viewed from the planetary gear assembly on a third axis parallel to the first axis and is connected to the first rotating component via a second power transmission mechanism. (f) When viewed from the direction of the first axis, the second axis is located at a position overlapping with the first motor.

[0006] Invention Effects According to the vehicle drive device of the present invention, (a) the planetary gear assembly has three rotating elements: a first rotating element, a second rotating element, and a third rotating element, and functions as a differential mechanism; (b) the engine and the first electric motor are connected to the first rotating element, the second electric motor is connected to the second rotating element, and the first drive shaft is connected to the third rotating element; (c) the second electric motor is positioned on the side opposite to the engine when viewed from the planetary gear assembly at the rotation axis of the planetary gear assembly, i.e., the first axis; and (d) the first drive shaft is connected via... An output shaft with a second axis of rotation parallel to the first axis and a first power transmission mechanism for transmitting power between the output shaft and the third rotating component are connected to the third rotating component without being connected via the interior of the connecting shaft connecting the second motor and the second rotating component. (e) When viewed from the planetary gear assembly, the first motor is positioned on the engine side on the third axis parallel to the first axis and is connected to the first rotating component via the second power transmission mechanism. (f) When viewed from the direction of the first axis, the second axis is located at a position overlapping with the first motor. Therefore, it is possible to suppress the increase in size of the first drive unit when viewed from the direction of the first axis, and to suppress the increase in the size of the first motor or the second motor, thus preventing an increase in the cost of the first motor or the second motor. Attached Figure Description

[0007] Figure 1 This is a diagram illustrating the schematic structure of a vehicle equipped with the vehicle drive device according to Embodiment 1.

[0008] Figure 2 This is a collinearity diagram illustrating the BEV_MG3 mode.

[0009] Figure 3 It is a collinear diagram illustrating the series mode.

[0010] Figure 4 This is a collinear diagram illustrating the input segmentation patterns.

[0011] Figure 5 This is a collinear diagram illustrating the output segmentation pattern.

[0012] Figure 6 This is a diagram illustrating the schematic structure of a vehicle equipped with the vehicle drive device according to Embodiment 2.

[0013] Figure 7 This is a collinear diagram illustrating the input segmentation patterns. Detailed Implementation

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, unless specifically mentioned otherwise, the drawings in each embodiment are appropriately simplified or modified, and the dimensional proportions and shapes of the parts are not necessarily depicted accurately.

[0015] Example 1 Figure 1 This is a diagram illustrating the schematic structure of a vehicle 90 equipped with the vehicle drive unit 10 according to Embodiment 1.

[0016] Vehicle 90 is a hybrid electric vehicle (HEV) or a plug-in hybrid electric vehicle (PHEV). Furthermore, vehicle 90 is an all-wheel drive vehicle capable of independently driving the left and right front wheels 14f and the left and right rear wheels 14r. All-wheel drive (AWD) and four-wheel drive (4WD) have the same meaning. Additionally, "left and right" refers to left and right relative to the direction of travel of vehicle 90. Hereinafter, "left and right front wheels 14f" and "left and right rear wheels 14r" will be abbreviated as "front wheels 14f" and "rear wheels 14r," respectively.

[0017] The vehicle 90 includes an engine 12, wheels 14 including front wheels 14f and rear wheels 14r, a first power transmission path between the engine 12 and the front wheels 14f, and a second power transmission path between the engine 12 and the rear wheels 14r. Furthermore, the vehicle 90 includes an inverter 70, a battery 72, and an electronic control unit 80.

[0018] Engine 12 is a power source for driving and is a known internal combustion engine. The engine torque Te [N·m], which is the output torque of engine 12, is controlled by electronic control unit 80. Furthermore, in this specification, unless otherwise specified, torque, driving force, power, and force (= power) have the same meaning. In two-wheel drive driving (=2WD driving), either the front wheel 14f or the rear wheel 14r becomes the drive wheel. In four-wheel drive driving (=4WD driving), both the front wheel 14f and the rear wheel 14r become the drive wheels.

[0019] In the first power transmission path, a front drive unit 20, a transfer case 22, a front drive shaft 24, a front differential 26, and left and right front drive shafts 28 are sequentially arranged from the engine 12 side. Except for the front drive unit 20, the structures are known. Hereinafter, the left and right front drive shafts 28 will be simply referred to as "front drive shafts 28". The transfer case 22 is a front-to-rear wheel power distribution device capable of distributing input power to the front wheels 14f and the rear wheels 14r. The front drive unit 20 is a unit that drives at least one of the front wheels 14f and the rear wheels 14r, and is equivalent to the "first drive unit" in this invention. The front drive shaft 28 is equivalent to the "first drive shaft" in this invention.

[0020] The front drive unit 20 includes a first electric motor MG1, a second electric motor MG2, and a planetary gear assembly 40 with three rotating components. The first electric motor MG1 and the second electric motor MG2 are rotating electrical machines that function as a prime mover and a generator, respectively, i.e., electric generators, such as three-phase synchronous motors. The structure of the front drive unit 20 will be described later.

[0021] In the second power transmission path, from the engine 12 side, the following components are arranged sequentially: a front drive unit 20, a transfer case 22, a rear drive shaft 30 that transmits power distributed by the transfer case 22 to the rear wheels 14r in the front-rear wheel distribution mode described later, an electronically controlled coupling device 32, a transmission shaft 34, a rear differential 36, and left and right rear drive shafts 38. These are known structures. A third electric motor MG3 is connected to the transmission shaft 34. The third electric motor MG3 is a rotating electrical machine that functions as both a prime mover and a generator, i.e., a so-called electric generator, such as a three-phase synchronous motor. Hereinafter, the left and right rear drive shafts 38 will be simply referred to as "rear drive shafts 38". The electronically controlled coupling device 32 can adjust the torque transmitted from the transfer case 22 to the rear differential 36 by controlling its transmission torque capacity (also called tightening torque). The transmission shaft 34 and the third electric motor MG3 constitute the rear drive unit 60. The structure of the rear drive unit 60 will be described later. The rear drive unit 60 is the unit that drives the rear wheel 14r of the front wheel 14f and the rear wheel 14r, and is equivalent to the "second drive unit" in this invention. The rear drive shaft 38 is equivalent to the "second drive shaft" in this invention.

[0022] Inverter 70 is a known power supply circuit that converts DC to AC or AC to DC. First motor MG1, second motor MG2, and third motor MG3 are each connected to battery 72 via inverter 70. The torque of first motor MG1, second motor MG2, and third motor MG3 is controlled by inverter 70 via electronic control device 80 (described later). The output torque of first motor MG1 is Tmg1 [N·m], the output torque of second motor MG2 is Tmg2 [N·m], and the output torque of third motor MG3 is Tmg3 [N·m]. The motor torque is the driving torque when the motor functions as a prime mover, and the regenerative torque when the motor functions as a generator. Battery 72 is an energy storage device that receives and generates power from first motor MG1, second motor MG2, and third motor MG3. For example, the first motor MG1, the second motor MG2, and the third motor MG3 are controlled by the inverter 70 to synchronously transmit and receive power. "Synchronous" means, for example, that the first motor MG1, the second motor MG2, and the third motor MG3 are each set to a state in which they can independently and simultaneously perform power operation or regeneration.

[0023] Thus, the vehicle drive unit 10 includes an engine 12, a front drive unit 20, a front drive shaft 28, a rear drive unit 60, and a rear drive shaft 38. The vehicle drive unit 10 is capable of front-wheel drive that transmits torque only to the front wheels 14f, and rear-wheel drive that transmits torque only to the rear wheels 14r.

[0024] In the front drive unit 20, the planetary gear assembly 40 and the second electric motor MG2 are arranged coaxially, with their rotation axis being the first axis C1. Both the first electric motor MG1 and the second electric motor MG2 are supported by the housing 18. The housing 18 is a non-rotating component, for example, a housing that houses the front drive unit 20, etc.

[0025] In the direction of the first axis C1, the second electric motor MG2 is positioned on the side opposite to the engine 12 when viewed from the planetary gear assembly 40. The planetary gear assembly 40 is a known double pinion type having a sun gear S, a carrier CA, and a ring gear R. The engine 12 is connected to the carrier CA via an engine connecting shaft 50, and the first electric motor MG1 is connected to it via a gear pair 54 as described later. The engine connecting shaft 50 is the input shaft from the engine 12 to the forward drive unit 20. The second electric motor MG2 is connected to the sun gear S. The transfer case 22 is connected to the ring gear R via a gear pair 44 and an output shaft 46. The gear pair 44 consists of gears 44a that mesh with each other and cannot rotate relative to the ring gear R, and gears 44b that are fixed so as not to rotate relative to the output shaft 46. The output shaft 46 is the output shaft from the forward drive unit 20 to the transfer case 22. The rotation axis of the output shaft 46 is a second axis C2 parallel to the first axis C1. Thus, by means of the output shaft 46 with the second axis C2 as its rotation axis and the gear pair 44, the connection to the front drive shaft 28 and the gear ring R is achieved without passing through the interior of the rotor shaft MG2r of the second motor MG2, which connects the second motor MG2 to the sun gear S. The gear pair 44 corresponds to the "first power transmission mechanism" in this invention. The rotor shaft MG2r, being the rotation axis connecting the second motor MG2 to the sun gear S, corresponds to the "connecting shaft" in this invention.

[0026] The carrier CA, sun gear S, and ring gear R correspond to the "first rotating element RE1", "second rotating element RE2", and "third rotating element RE3" in this invention, respectively. The planetary gear assembly 40 functions as a differential mechanism that sets the carrier CA, sun gear S, and ring gear R into a differential state. For example, the planetary gear assembly 40 mechanically divides the power input to the carrier CA into the sun gear S and the ring gear R.

[0027] For example, the second electric motor MG2 is driven by the power divided by the planetary gear unit 40. The second electric motor MG2 generates electricity using the power divided by the planetary gear unit 40. The planetary gear unit 40 functions as an electric continuously variable transmission (CVT) that controls the differential state of the planetary gear unit 40 by controlling the operating state of the second electric motor MG2. The electricity generated by the second electric motor MG2 is used to charge the battery 72, or to drive the first electric motor MG1 or the third electric motor MG3.

[0028] The first electric motor MG1 is positioned on the engine 12 side along a third axis C3 parallel to the first axis C1, as viewed from the planetary gear assembly 40. Preferably, in the direction of the first axis C1, the first electric motor MG1 is positioned between the engine 12 and the planetary gear assembly 40. The first electric motor MG1 is connected to the carrier CA via a gear pair 54. The gear pair 54 consists of gears 54a that mesh with each other and are fixed so as not to rotate relative to the engine connection shaft 50, and gears 54b that are fixed so as not to rotate relative to the rotor shaft MG1r of the first electric motor MG1. The gear pair 54 corresponds to the "second power transmission mechanism" in this invention.

[0029] For example, gear pair 54 functions as a reduction mechanism that reduces the speed to a lower speed than the first electric motor MG1 and connects the first electric motor MG1 to the engine 12 to transmit power. When the first electric motor MG1 functions as a prime mover, the gear pair 54 reduces the speed to a lower speed than the first electric motor speed Nmg1 [rpm], and the torque Tmg1 of the first electric motor is added to the engine torque Te. When the first electric motor MG1 functions as a generator, the gear pair 54 accelerates the first electric motor speed Nmg1 to a higher speed than the engine speed Ne [rpm], and the engine torque Te causes the first electric motor MG1 to rotate. The engine speed Ne and the first electric motor speed Nmg1 are the speeds of the engine 12 and the first electric motor MG1, respectively.

[0030] When viewed from the direction of the first axis C1, the second axis C2 is located at a position overlapping with the first motor MG1. Therefore, in the circumferential direction centered on the first axis C1, the gear pair 44, especially gear 44b, overlaps with the first motor MG1. Thus, when viewed from the direction of the first axis C1, the gear pair 44 and the first motor MG1 are at an overlapping position. Preferably, in the circumferential direction centered on the first axis C1, the second axis C2 and the third axis C3 are in the same direction. Therefore, when viewed from the direction of the first axis C1, the area of ​​overlap between the gear pair 44 and the first motor MG1 is maximized.

[0031] A brake BR is provided on the engine connecting shaft 50. One end of the brake BR is connected to the engine connecting shaft 50, and the other end is connected to the housing 18. The brake BR is an engaging device in which the components at both ends are selectively connected, for example, by an actuator such as an electric or hydraulic one. The brake BR functions as a braking mechanism that selectively stops the rotation of the engine connecting shaft 50.

[0032] The rear drive unit 60 includes a transmission shaft 34 and a third electric motor MG3. The third electric motor MG3 is supported, for example, by the vehicle body 62, which is a non-rotating component. For example, when the transfer case 22 is in the front-wheel distribution mode described later, the rear drive unit 60 inputs the power of the third electric motor MG3 to the rear differential 36. For example, when the transfer case 22 is in the front-rear wheel distribution mode described later, the rear drive unit 60 adds the power of the third electric motor MG3 to the power transmitted from the rear drive shaft 30 to the transmission shaft 34 and inputs it to the rear differential 36.

[0033] For example, the rear drive unit 60 is the main unit that is given higher priority for driving than the front drive unit 20.

[0034] In this case, the front drive unit 20 becomes the auxiliary unit.

[0035] The third motor MG3 of the rear drive unit 60 is connected to the rear wheel 14r, and can therefore be considered as being connected to the front wheel 14f via the ground. By controlling the synchronous transmission and reception of power to the first motor MG1, the second motor MG2, and the third motor MG3, driving can be performed as if the third motor MG3 is connected to the front wheel 14f.

[0036] The electronic control unit 80 is configured, for example, to include a so-called microcomputer, which performs various controls of the vehicle 90 by processing signals according to a pre-stored program.

[0037] Various signals detected by sensors on the vehicle 90 are input to the electronic control unit 80. These signals include, for example, engine speed Ne, vehicle speed V [km / h], first motor speed Nmg1, second motor speed Nmg2 [rpm], third motor speed Nmg3 [rpm], throttle opening θacc [%], shift position POSop, and state of charge (SOC) [%]. The second motor speed Nmg2 and third motor speed Nmg3 are the speeds of the second motor MG2 and third motor MG3, respectively. The throttle opening θacc represents the amount of throttle input by the driver. The shift position POSop is, for example, the position of the shift lever (not shown) such as "P", "R", "N", or "D". The state of charge (SOC) is, for example, the ratio of the actual stored charge to the preset full-charge capacity of the battery 72, calculated based on the battery charging / discharging current and battery voltage.

[0038] Various control signals are output from the electronic control unit 80 to various devices in the vehicle 90 (engine 12, inverter 70, brake BR, transfer case 22, electronic control coupling device 32, etc.). These signals include: engine control signal Se for controlling the operating state of engine 12; first motor control signal Smg1, second motor control signal Smg2, and third motor control signal Smg3, which are controlled by inverter 70 to control the operating states of first motor MG1 to third motor MG3 respectively; brake control signal Sbr for controlling the disconnection state of brake BR; transfer case control signal Str, which selectively selects the distribution mode of transfer case 22; and torque control signal Sc, which controls the torque transmission capacity of electronic control coupling device 32. The transfer case 22 has two distribution modes: a front wheel distribution mode that distributes all the input power to the front wheels 14f, and a front-rear wheel distribution mode that distributes the input power to both the front wheels 14f and the rear wheels 14r.

[0039] The electronic control unit 80 is configured to switch the drive mode to any of several modes by controlling the engine 12, the first electric motor MG1, the second electric motor MG2, and the third electric motor MG3. When switching drive modes, the electronic control unit 80 controls the operation by engaging the brake BR as needed. For example, the multiple drive modes include BEV_MG3 mode, series mode, input split mode, and output split mode.

[0040] Here, with the transfer case 22 in front wheel distribution mode, using Figures 2-5 The various driving modes that can switch the vehicle's 90° driving mode are explained. Figures 2-5 These are diagrams showing the rotational speeds of the rotating components RE1 to RE3 of the planetary gear assembly 40. In this collinear diagram, the vertical lines Y1 to Y3 represent the rotating components of the planetary gear assembly 40: the sun gear S, the ring gear R, and the carrier CA, respectively. Figures 2-5 In the diagram, "ENG" represents engine 12, "FrOUT" represents front wheel 14f, and "RrOUT" represents rear wheel 14r. Furthermore, each arrow indicates the magnitude or direction of torque. Solid arrows represent the torque output from each actuator, while dashed arrows represent the transmitted torque. Figures 2-5 In the figure, the rotational speeds (Nmg1, Nmg3) and torques (Tmg1, Tmg3) of the first motor MG1 and the third motor MG3 are shown as converted values ​​on the carrier CA and the gear ring R, respectively.

[0041] Figure 2This is a collinearity diagram illustrating the BEV_MG3 mode. The BEV_MG3 mode is as follows: the brake BR is engaged, the engine 12 is stopped, and in order to generate the driving force Fr[N] for the vehicle 90, the third electric motor MG3 outputs a positive torque Tmg3. "Positive torque" refers to the torque in the same direction as the output torque of the engine 12 (i.e., the engine torque Te) if the engine 12 is running, and the torque that propels the vehicle 90 forward.

[0042] "Negative torque" refers to torque that acts in the opposite direction to positive torque. BEV_MG3 mode is for driving a Battery Electric Vehicle (BEV). In BEV_MG3 mode, the first motor MG1 is set to a non-driving state. "Non-driving state" means that neither the prime mover nor the generator is operating. In BEV_MG3 mode, control is not based on balancing the generated and consumed power; instead, the third motor MG3 is driven by power supplied from battery 72.

[0043] Figure 3 This is a collinear diagram illustrating the series mode. In series mode, the brake BR is released, the engine 12 is running, and the third motor torque Tmg3, which generates positive torque, is output from the third motor MG3 via the electricity generated by the first electric motor MG1. Series mode enables hybrid electric vehicle (HEV) operation, specifically enabling series operation powered by the engine 12. In series mode, the first electric motor torque Tmg1 is negative torque; the first electric motor MG1 operates as a generator using the power from the engine 12, while the third electric motor MG3 operates as a prime mover. In series mode, the explosive vibrations of the engine 12 are not transmitted to the front drive shaft 28, thus helping to eliminate muffled noises, etc.

[0044] Figure 4This is a collinear diagram illustrating the input split mode. The input split mode is a mode where the brake BR is released, the engine 12 is in an operating state, the first electric motor MG1 is in a non-driving state, and the third electric motor torque Tmg3, which is positive torque, is output from the third electric motor MG3 via the electricity generated by the second electric motor MG2. The input split mode enables hybrid driving and specifically enables input split driving powered by the engine 12. In the input split mode, the second electric motor MG2 rotates in the negative direction and its torque Tmg2 is positive; the second electric motor MG2 functions as a generator, and the third electric motor MG3 functions as a prime mover. The planetary gear unit 40 is in a differential state, and the positive torque is mechanically transmitted to the ring gear R via the reaction force of the engine torque Te obtained from the second electric motor MG2. Furthermore, the electricity generated by the second electric motor MG2 is supplied to the third electric motor MG3, and the third electric motor torque Tmg3, which is positive torque, is output from the third electric motor MG3.

[0045] Figure 4 The double-dotted line A1 indicates that in the planetary gear unit 40, by setting the rotational speed of the second rotating element RE2 (the rotational speed Nmg2 of the second electric motor) to zero, the power of the second electric motor MG2 is also set to zero, thus creating a mechanical point where no electrical work is performed. In this mechanical point, the rotational speed of the third rotating element RE3, which is an output element of the planetary gear unit 40, is set to the reduction side, i.e., the low gear (U / D) side, relative to the engine speed Ne. That is, the mechanical point of the planetary gear unit 40 is set to the reduction ratio α (=Nre3 / Ne<1). Furthermore, the rotational speed Nre3 [rpm] is the rotational speed of the third rotating element RE3.

[0046] Figure 5 This is a collinear diagram illustrating the output split mode. The output split mode is a mode in which the brake BR is released, the engine 12 is activated, and the states of the first electric motor MG1 and the second electric motor MG2 are controlled in a way that balances their electrical output. In the output split mode, one of the first electric motor MG1 and the second electric motor MG2 operates as a prime mover, while the other operates as a generator. The output split mode enables hybrid driving and specifically enables output split driving powered by the engine 12. Figure 5 As shown in (a), in the output split mode, when the second motor MG2 is rotating in the positive direction, the second motor MG2 is controlled to work as a prime mover by setting the torque Tmg2 of the second motor to a positive torque, and the first motor MG1 is controlled to work as a generator by setting the torque Tmg1 of the first motor to a negative torque. Figure 5As shown in (b), in the output split mode, when the second motor MG2 rotates in the negative direction, the torque Tmg2 of the second motor is set to a positive torque, and the second motor MG2 is controlled to work as a generator. The torque Tmg1 of the first motor is set to a positive torque, and the first motor MG1 is controlled to work as a prime mover. The planetary gear unit 40 is set to differential mode, and the torque is mechanically transmitted to the gear ring R by the reaction force of the combined torque Tsum (=Te+Tmg1) of the engine torque Te obtained by the second motor MG2 and the torque Tmg1 of the first motor. The third motor MG3 is set to non-driving mode.

[0047] The above uses Figures 3-5 The description covers several modes in which the drive mode of the vehicle 90 can be switched when the transfer case 22 is in front-wheel distribution mode. However, the vehicle 90 can also be switched to other modes. For example, different modes can be set by setting the transfer case 22 to front-to-rear wheel distribution mode among the aforementioned modes.

[0048] According to this embodiment, (a) the planetary gear unit 40 has three rotating elements: a first rotating element RE1, a second rotating element RE2, and a third rotating element RE3, and functions as a differential mechanism; (b) the first rotating element RE1 is connected to an engine 12 and a first electric motor MG1, the second rotating element RE2 is connected to a second electric motor MG2, and the third rotating element RE3 is connected to a front drive shaft 28; (c) the second electric motor MG2 is positioned on the first shaft center C1 on the side opposite to the engine 12 when viewed from the planetary gear unit 40; and the front drive shaft 28 is connected via a... The output shaft 46, with a second axis C2 parallel to the first axis C1 as its rotation axis, and the gear pair 44 that transmits power between the output shaft 46 and the third rotating element RE3, are connected to the third rotating element RE3 without passing through the interior of the rotor shaft MG2r. (d) The first motor MG1 is positioned on the engine 12 side on the third axis C3 parallel to the first axis C1 when viewed from the planetary gear assembly 40 and is connected to the first rotating element RE1 via the gear pair 54. (e) When viewed from the direction of the first axis C1, the second axis C2 is located at a position overlapping with the first motor MG1. Thus, when viewed from the direction of the first axis C1, the gear pair 44 and the first motor MG1 are located at an overlapping position, thereby suppressing the increase in size of the front drive unit 20 when viewed from the direction of the first axis C1. Furthermore, it is not necessary to insert other rotating shafts into the interior of the rotor shaft MG1r or the rotor shaft MG2r. Therefore, the increased cost of the first electric motor MG1 or the second electric motor MG2 due to their larger size can also be suppressed. Furthermore, since the first shaft C1 and the second shaft C2 are parallel to each other, "viewing from the direction of the first shaft C1" is the same as viewing from the rotational axis direction of the engine connecting shaft 50 (which serves as the input shaft of the front drive unit 20) and the output shaft 46 (which serves as the output shaft), and is also viewed from the rotational axis direction of the input and output shafts of the front drive unit 20.

[0049] According to this embodiment, (a) the planetary gear device 40 is a double pinion type, (b) the first rotating element RE1 is set as the carrier CA, the second rotating element RE2 is set as the sun gear S, and the third rotating element RE3 is set as the ring gear R. With this connection structure of the double pinion type planetary gear device 40, the mechanical point can be set with a reduction ratio α.

[0050] According to this embodiment, a rear drive unit 60 is provided, which includes (a) a rear drive shaft 38 and a third electric motor MG3 connected to the rear drive shaft 38. With this structure, for example, the driving mode of the vehicle 90 can include so-called tandem driving. Compared to the case without the rear drive unit 60, multiple driving modes can be achieved when the rear drive unit 60 is provided.

[0051] Example 2 Figure 6 This is a diagram illustrating the schematic structure of the vehicle drive unit 110 according to Embodiment 2. The vehicle drive unit 110 is mounted on a vehicle 190. The structure of the vehicle 190 is substantially the same as that of the vehicle 90 according to Embodiment 1, except that the front drive unit 120 replaces the front drive unit 20. Therefore, in this embodiment, the description focuses on the parts that are different from those in Embodiment 1, and the parts that are substantially the same as those in Embodiment 1 in function are labeled with the same symbols and the description is omitted as appropriate.

[0052] An engine 12 is connected to a gear ring R via an engine connecting shaft 50, and a first electric motor MG1 is connected to a gear pair 54. A second electric motor MG2 is connected to a sun gear S. A transfer case 22 is connected to a carrier CA via a gear pair 44 and an output shaft 46. Thus, in this embodiment, the connection relationship between the planetary gear assembly 40, the engine 12, the first electric motor MG1, the second electric motor MG2, and the transfer case 22 differs from that in Embodiment 1.

[0053] Figure 7 This is a collinear diagram illustrating the input segmentation patterns. Figure 7 It is the same as in Example 1 Figure 4 The corresponding collinearity diagram in this embodiment. Figure 7 The double-dotted line A2 indicates a state where a mechanical point is formed in the planetary gear unit 40. In this mechanical point, the rotational speed of the third rotational element RE3, which is an output element of the planetary gear unit 40, is set to the acceleration side, i.e., the overdrive (O / D) side, relative to the engine speed Ne. That is, the mechanical point of the planetary gear unit 40 is set to an acceleration ratio β (=Nre3 / Ne>1).

[0054] According to this embodiment, the same effect based on the structure is achieved by having the same structure as in the aforementioned embodiment 1.

[0055] According to this embodiment, (a) the planetary gear device 40 is a double pinion type, (b) the first rotating element RE1 is set as a ring gear R, the second rotating element RE2 is set as a sun gear S, and the third rotating element RE3 is set as a carrier CA. With this connection structure of the double pinion type planetary gear device 40, the mechanical point can be set with an acceleration ratio β.

[0056] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is also applicable to other methods.

[0057] The aforementioned embodiments 1 and 2 involve the output shaft 46 being connected to the third rotating element RE3 via a gear pair 44, and the first motor MG1 being connected to the first rotating element RE1 via a gear pair 54. However, the present invention is not limited to this method. For example, a chain and sprocket can be used instead of gear pairs 44 or 54 for the connection. The replaced chain and sprocket correspond to the "first power transmission mechanism" or "second power transmission mechanism" in the present invention.

[0058] In the aforementioned embodiments 1 and 2, the present invention is provided with a transfer case 22, a front drive shaft 24, a rear drive shaft 30, and an electronically controlled coupling device 32. However, the present invention is not limited to this embodiment. For example, the present invention can also be applied to a configuration where these components are not present and the output shaft 46 is connected to the front differential gear 26.

[0059] In the aforementioned embodiments 1 and 2, the planetary gear device 40 is a double pinion type, but the present invention is not limited thereto. For example, the present invention can also be applied to a configuration where the planetary gear device 40 is a single pinion type. When the planetary gear device 40 is a single pinion type, and the first rotating element RE1 is a ring gear R, the second rotating element RE2 is a sun gear S, and the third rotating element RE3 is a carrier CA, the mechanical point can be set with a reduction ratio α. When the planetary gear device 40 is a single pinion type, and the first rotating element RE1 is a carrier CA, the second rotating element RE2 is a sun gear S, and the third rotating element RE3 is a ring gear R, the mechanical point can be set with an acceleration ratio β.

[0060] In the aforementioned embodiments 1 and 2, a braking mechanism that uses a one-way clutch to stop the rotation of the first rotating element RE1 can be used instead of the brake BR. Furthermore, in the aforementioned embodiments 1 and 2, it is not necessary to provide a brake BR.

[0061] In the aforementioned embodiments 1 and 2, the rear drive unit 60 includes a third electric motor MG3, but the present invention can also be applied to a configuration without the third electric motor MG3. Furthermore, in this configuration, the mode using the third electric motor MG3 is not included among the multiple modes that allow switching the drive modes of vehicles 90 and 190.

[0062] In the aforementioned embodiments 1 and 2, one of the front wheel 14f and the rear wheel 14r that transmits power to the engine 12 or the second electric motor MG2 is the rear wheel 14r, and the other of the front wheel 14f and the rear wheel 14r that transmits power to the third electric motor MG3 can be the front wheel 14f. That is, the "first drive shaft" can be the rear drive shaft 38, and the "second drive shaft" can be the front drive shaft 28.

[0063] Furthermore, the above is only one embodiment, and the present invention can be modified and improved in various ways based on the knowledge of those skilled in the art.

[0064] Symbol Explanation 10 - Vehicle drive unit, 12 - Engine, 14f - Front wheel, 14r - Rear wheel, 20 - Front drive unit (first drive unit), 28 - Front drive shaft (first drive shaft), 38 - Rear drive shaft (second drive shaft), 40 - Planetary gear assembly, 44 - Gear pair (first power transmission mechanism), 46 - Output shaft, 54 - Gear pair (second power transmission mechanism), 60 - Rear drive unit (second drive unit), C1 - First shaft center, C2 - Second shaft center, C3 - Third shaft center, CA - Carrier, MG1 - First electric motor, MG2 - Second electric motor, MG2r - Rotor shaft (connecting shaft), MG3 - Third electric motor, R - Ring gear, RE1 - First rotating component, RE2 - Second rotating component, RE3 - Third rotating component, S - Sun gear.

Claims

1. A vehicle drive system comprising: an engine; a first drive unit including a first electric motor, a second electric motor, and a planetary gear assembly having three rotating elements; and a first drive shaft for driving one of a front wheel and a rear wheel, characterized in that, The planetary gear mechanism has three rotating components: a first rotating component, a second rotating component, and a third rotating component, and functions as a differential mechanism. The engine and the first electric motor are connected to the first rotating component, the second electric motor is connected to the second rotating component, and the first drive shaft is connected to the third rotating component. The second electric motor is positioned on the side opposite to the engine when viewed from the planetary gear assembly, on the rotation axis of the planetary gear assembly, i.e., the first axis. The first drive shaft is connected to the third rotating component via an output shaft with a second axis of rotation parallel to the first axis and a first power transmission mechanism that transmits power between the output shaft and the third rotating component, without needing to pass through the interior of the connecting shaft connecting the second motor and the second rotating component. The first electric motor is positioned on the engine side from the planetary gear assembly on a third axis parallel to the first axis and is connected to the first rotating component via a second power transmission mechanism. When viewed from the direction of the first axis, the second axis is located at a position overlapping with the first motor.

2. The vehicle drive device according to claim 1, characterized in that, The planetary gear assembly includes a sun gear, a carrier, and a gear ring. In the case where the planetary gear assembly is a single pinion type, the first rotating element is the ring gear, the second rotating element is the sun gear, and the third rotating element is the carrier. In the case where the planetary gear device is a double pinion type, the first rotating element is the carrier, the second rotating element is the sun gear, and the third rotating element is the ring gear.

3. The vehicle drive device according to claim 1, characterized in that, The planetary gear assembly includes a sun gear, a carrier, and a gear ring. In the case where the planetary gear assembly is a single pinion type, the first rotating element is the carrier, the second rotating element is the sun gear, and the third rotating element is the ring gear. In the case where the planetary gear device is a double pinion type, the first rotating element is the gear ring, the second rotating element is the sun gear, and the third rotating element is the carrier.

4. The vehicle drive unit according to any one of claims 1 to 3, characterized in that, It also includes a second drive shaft that drives the other of the front wheel and the rear wheel, and a second drive unit that includes a third electric motor connected to the second drive shaft.

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