Vehicular driving device

Abstract

To impart a turning function to a vehicle with usage of a differential mechanism.SOLUTION: A vehicular driving device includes a differential mechanism having a first side gear connected to a first wheel via a first power transmission path, and a second side gear connected to a second wheel via a second power transmission path. The vehicular driving device includes a first planetary gear mechanism provided in the first power transmission path and having a first rotary element, a second rotary element, and a third rotary element. The vehicular driving device includes a second planetary gear mechanism provided in the second power transmission path and having a fourth rotary element, a fifth rotary element, and a sixth rotary element.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a vehicle drive device. [Background technology]

[0002] 2. Description of the Related Art Vehicles such as automobiles have a differential mechanism that distributes driving force to left and right drive wheels (see Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 7-108841 [Patent Document 2] Japanese Utility Model Application Publication No. 51-4028 [Patent Document 3] Japanese Utility Model Application Publication No. 59-78181 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in order to facilitate driving operations in narrow spaces, it has been considered to provide a vehicle with a turning function such as a spin turn or a pivot turn. For example, it is possible to provide a vehicle with a turning function such as a spin turn by controlling the rotation direction of each wheel using an in-wheel motor. However, since the adoption of an in-wheel motor increases costs, it is desired to provide a vehicle with a turning function such as a spin turn using a technologically mature differential mechanism. [Means for solving the problem]

[0005] According to the present disclosure, a vehicle drive device has a differential mechanism including a differential case connected to a power source, a first side gear connected to a first wheel via a first power transmission path, and a second side gear connected to a second wheel via a second power transmission path. The vehicle drive device has a first planetary gear mechanism provided in the first power transmission path and including a first rotating element, a second rotating element, and a third rotating element. The vehicle drive device has a first clutch mechanism that fastens at least two rotating elements among the first rotating element, the second rotating element, and the third rotating element to each other. The vehicle drive device has a first brake mechanism that operates in a fastened state that stops the rotation of the second rotating element and a released state that allows the rotation of the second rotating element. The vehicle drive device has a second planetary gear mechanism provided in the second power transmission path and including a fourth rotating element, a fifth rotating element, and a sixth rotating element. The vehicle drive device has a second clutch mechanism that fastens at least two of the fourth, fifth, and sixth rotating elements to each other. The vehicle drive device has a second brake mechanism that operates in a fastened state that stops the rotation of the sixth rotating element and a released state that allows the rotation of the sixth rotating element. The first planetary gear mechanism has a structure in which the first rotating element and the third rotating element are arranged at both ends on a collinear diagram. The first rotating element is connected to the first side gear, and the third rotating element is connected to the first wheel. The second planetary gear mechanism has a structure in which the fourth rotating element and the sixth rotating element are arranged at both ends on a collinear diagram. The fourth rotating element is connected to the second side gear, and the fifth rotating element is connected to the second wheel. Effect of the Invention

[0006] According to the present disclosure, a differential mechanism can be used to provide a vehicle with turning capability. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram illustrating an example of a vehicle including a vehicle drive device according to an embodiment. [Diagram 2] FIG. 2 is a diagram illustrating an example of an electric axle. [Diagram 3] FIG. 1 is a diagram illustrating an example of a control system for controlling an electric axle. [Figure 4] FIG. 2 is a diagram illustrating an example of a basic structure of a control unit. [Figure 5A] FIG. 11 is a diagram illustrating the operation state of an electric axle during acceleration and constant speed driving. [Figure 5B] FIG. 5B is a collinear diagram showing an operating state of the electric axle shown in FIG. 5A. [Figure 6A] FIG. 4 is a diagram illustrating an operation state of an electric axle during coasting. [Figure 6B] FIG. 6B is a collinear diagram showing an operating state of the electric axle shown in FIG. 6A. [Figure 7A] FIG. 11 is a diagram illustrating an operation state of an electric axle during turning. [Figure 7B] FIG. 7B is a collinear diagram showing an operating state of the electric axle shown in FIG. 7A. [Figure 8] FIG. 11 is a diagram showing an example of a turning running situation. [Figure 9] FIG. 11 is a diagram showing an example of a vehicle equipped with a vehicle drive device according to another embodiment. [Figure 10] FIG. 2 is a diagram showing an example of a state in which a vehicle is turning; [Figure 11] FIG. 13 is a diagram showing an electric axle constituting a vehicle drive device according to another embodiment. [Figure 12A] FIG. 11 is a diagram illustrating the operation state of an electric axle during acceleration and constant speed driving. [Figure 12B] FIG. 12B is a collinear diagram showing an operating state of the electric axle shown in FIG. 12A. [Figure 13A] FIG. 11 is a diagram illustrating an operation state of an electric axle during deceleration driving. [Figure 13B] FIG. 13B is a collinear diagram showing an operating state of the electric axle shown in FIG. 13A. [Figure 14A] FIG. 11 is a diagram illustrating an operation state of an electric axle during turning. [Figure 14B]FIG. 14B is a collinear diagram showing an operating state of the electric axle shown in FIG. 14A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following description, the same or substantially the same configurations and elements will be denoted by the same reference numerals and repeated description will be omitted.

[0009] First Embodiment <Vehicle> Fig. 1 is a diagram showing an example of a vehicle 11 equipped with a vehicle driving device 10 according to an embodiment of the present disclosure. As shown in Fig. 1, the vehicle 11 has an electric axle 20 that drives a right rear wheel (first wheel) 20R and a left rear wheel (second wheel) 20L. The electric axle 20 constituting the vehicle driving device 10 has a motor generator (power source) 21, a differential mechanism 22, a first planetary gear mechanism 23, and a second planetary gear mechanism 24. A battery pack (not shown) is connected to the motor generator 21 via an inverter 62 (described later).

[0010] <Electric axle> FIG. 2 is a diagram showing an example of an electric axle 20. As shown in FIG. 2, the electric axle 20 has a housing 30 including a motor housing portion 30a and a differential housing portion 30b. The motor generator 21 is housed in the motor housing portion 30a of the housing 30, and the differential mechanism 22 is housed in the differential housing portion 30b of the housing 30. The motor generator 21 has a stator 31 around which a stator coil 31a is wound, and a rotor 33 housed inside the stator 31 and including a drive gear 32. The differential mechanism 22 has a differential case 35 including a driven gear 34, a pinion 36 rotatably supported by the differential case 35, a first side gear 37 meshing with the pinion 36, and a second side gear 38 meshing with the pinion 36. The driven gear 34 of the differential case 35 and the drive gear 32 of the rotor 33 are connected to each other via an intermediate gear 39. In other words, the differential case 35 is connected to the motor generator 21.

[0011] The first side gear 37 of the differential mechanism 22 is connected to the right rear wheel 20R via a first power transmission path 41. The first power transmission path 41 is composed of an output shaft 42 connected to the first side gear 37, a first planetary gear mechanism 23 connected to the output shaft 42, and an axle 43 connected to the first planetary gear mechanism 23. That is, the first power transmission path 41 connecting the first side gear 37 and the right rear wheel 20R is provided with the first planetary gear mechanism 23. The first planetary gear mechanism 23 has a sun gear (first rotating element) S1 connected to the first side gear 37 via the output shaft 42, a ring gear (third rotating element) R1 also called an internal gear arranged radially outside the sun gear S1, and a carrier (second rotating element) C1 that rotatably supports a pinion P1 meshing with the sun gear S1 and the ring gear R1. In addition, the ring gear R1 of the first planetary gear mechanism 23 is connected via an axle 43 to the right rear wheel 20R.

[0012] The output shaft 42 and the carrier C1 are connected to each other via a first clutch mechanism CL1. By controlling this first clutch mechanism CL1 to an engaged state, the sun gear S1 and the carrier C1 can be connected to each other. On the other hand, by controlling the first clutch mechanism CL1 to a released state, the sun gear S1 and the carrier C1 can be separated from each other. In addition, the housing 30 and the carrier C1 are connected to each other via a first brake mechanism BR1. By controlling this first brake mechanism BR1 to an engaged state, the carrier C1 can be connected to the housing 30 to stop the rotation of the carrier C1. On the other hand, by controlling the first brake mechanism BR1 to a released state, the carrier C1 can be separated from the housing 30 to allow the rotation of the carrier C1.

[0013] The second side gear 38 of the differential mechanism 22 is connected to the left rear wheel 20L via a second power transmission path 51. The second power transmission path 51 is composed of an output shaft 52 connected to the second side gear 38, a second planetary gear mechanism 24 connected to the output shaft 52, and an axle 53 connected to the second planetary gear mechanism 24. That is, the second power transmission path 51 connecting the second side gear 38 and the left rear wheel 20L is provided with the second planetary gear mechanism 24. The second planetary gear mechanism 24 has a sun gear (fourth rotating element) S2 connected to the second side gear 38 via the output shaft 52, a ring gear (sixth rotating element) R2 also called an internal gear arranged radially outward of the sun gear S2, and a carrier (fifth rotating element) C2 that rotatably supports a pinion P2 meshing with the sun gear S2 and the ring gear R2. The carrier C2 of the second planetary gear mechanism 24 is connected to the left rear wheel 20L via an axle 53.

[0014] The output shaft 52 and the ring gear R2 are connected to each other via a second clutch mechanism CL2. By controlling this second clutch mechanism CL2 to an engaged state, the sun gear S2 and the ring gear R2 can be connected to each other. On the other hand, by controlling the second clutch mechanism CL2 to a released state, the sun gear S2 and the ring gear R2 can be separated from each other. In addition, the housing 30 and the ring gear R2 are connected to each other via a second brake mechanism BR2. By controlling this second brake mechanism BR2 to an engaged state, the ring gear R2 can be connected to the housing 30 to stop the rotation of the ring gear R2. On the other hand, by controlling the second brake mechanism BR2 to a released state, the ring gear R2 can be separated from the housing 30 to allow the rotation of the ring gear R2.

[0015] <Control system> Fig. 3 is a diagram showing an example of a control system 60 that controls the electric axle 20. As shown in Fig. 3, the vehicle drive device 10 has a control system 60 consisting of multiple electronic control units. The electronic control units that make up the control system 60 include an axle control unit 61 for controlling the electric axle 20.

[0016] The axle control unit 61 outputs a control signal to an inverter 62 connected to the stator 31 of the motor generator 21, and controls the motor torque and motor rotation speed of the motor generator 21. The axle control unit 61 also outputs a control signal to an actuator 63 that drives the first clutch mechanism CL1, and outputs a control signal to an actuator 64 that drives the first brake mechanism BR1. That is, the axle control unit 61 controls the first clutch mechanism CL1 to an engaged state and a released state, and controls the first brake mechanism BR1 to an engaged state and a released state. The axle control unit 61 also outputs a control signal to an actuator 65 that drives the second clutch mechanism CL2, and outputs a control signal to an actuator 66 that drives the second brake mechanism BR2. That is, the axle control unit 61 controls the second clutch mechanism CL2 to an engaged state and a released state, and controls the second brake mechanism BR2 to an engaged state and a released state. The actuators 63 to 66 may be electric actuators driven by an electric motor or the like, or may be hydraulic actuators driven by hydraulic pressure.

[0017] Furthermore, the electronic control units constituting the control system 60 include a vehicle control unit 70 that outputs a control signal to the axle control unit 61. These control units 61, 70 are communicably connected to each other via an in-vehicle network 71 such as a Controller Area Network (CAN). The vehicle control unit 70 sets an operation target for the electric axle 20 based on input information from various control units and various sensors described below. The vehicle control unit 70 also generates a control signal according to the operation target for the electric axle 20, and outputs this control signal to the axle control unit 61.

[0018] Sensors connected to the vehicle control unit 70 include an accelerator sensor 72 that detects the operation state of an accelerator pedal, a brake sensor 73 that detects the operation state of a brake pedal, and a vehicle speed sensor 74 that detects the vehicle speed, which is the traveling speed of the vehicle 11. Also connected to the vehicle control unit 70 is a start switch 75 that is operated when starting and stopping the control system 60, and a turn switch 76 that is operated when making a pivot turn of the vehicle 11.

[0019] Fig. 4 is a diagram showing an example of the basic structure of the control units 61, 70. As shown in Fig. 4, the control units 61, 70, which are electronic control units, have a microcontroller 82 incorporating a processor 80 and a main memory (memory) 81, etc. A predetermined program is stored in the main memory 81, and the program is executed by the processor 80. The processor 80 and the main memory 81 are connected to each other so that they can communicate with each other. Note that a plurality of processors 80 may be incorporated in the microcontroller 82, and a plurality of main memories 81 may be incorporated in the microcontroller 82.

[0020] Moreover, the control units 61 and 70 have an input circuit 83, a drive circuit 84, a communication circuit 85, an external memory 86, a power supply circuit 87, and the like. The input circuit 83 converts signals input from various sensors into signals that can be input to the microcontroller 82. The drive circuit 84 generates drive signals for various devices such as the inverter 62 and the actuators 63 to 66 described above based on signals output from the microcontroller 82. The communication circuit 85 converts signals output from the microcontroller 82 into communication signals directed to other control units. The communication circuit 85 also converts communication signals received from other control units into signals that can be input to the microcontroller 82. Furthermore, the power supply circuit 87 supplies a stable power supply voltage to the microcontroller 82, the input circuit 83, the drive circuit 84, the communication circuit 85, the external memory 86, and the like. Moreover, the external memory 86, which is a non-volatile memory, stores programs and various data, and the like.

[0021] <Electric axle operation status> <Acceleration and constant speed driving> FIG. 5A is a diagram showing the operating state of the electric axle 20 during acceleration and constant speed running, and FIG. 5B is a collinear diagram showing the operating state of the electric axle 20 shown in FIG. 5A. As shown in FIG. 5A, during acceleration and constant speed running, the control system 60 controls the first and second brake mechanisms BR1 and BR2 to be in a released state, and controls the first and second clutch mechanisms CL1 and CL2 to be in an engaged state. In this way, by releasing the first brake mechanism BR1 and engaging the first clutch mechanism CL1, the respective rotating elements of the first planetary gear mechanism 23 can be rotated together, and the rotation of the first side gear 37 can be transmitted directly to the right rear wheel 20R. Similarly, by releasing the second brake mechanism BR2 and engaging the second clutch mechanism CL2, the respective rotating elements of the second planetary gear mechanism 24 can be rotated together, and the rotation of the second side gear 38 can be transmitted directly to the left rear wheel 20L. That is, as shown in FIG. 5B, the rotational speeds of the sun gear S1 and the ring gear R1 can be made to match each other, and the rotational speeds of the sun gear S2 and the carrier C2 can be made to match each other.

[0022] As shown in Fig. 5A, when traveling forward, the motor generator 21 is driven in the forward direction (direction of arrow a10). This allows the motor driving force to be distributed to the left and right via the differential mechanism 22, and the right rear wheel 20R and the left rear wheel 20L can be rotated in the forward direction (direction of arrow a11, direction of arrow a12). On the other hand, when traveling backward, the motor generator 21 is driven in the backward direction (direction of arrow b10). This allows the motor driving force to be distributed to the left and right via the differential mechanism 22, and the right rear wheel 20R and the left rear wheel 20L can be rotated in the backward direction (direction of arrow b11, direction of arrow b12).

[0023] In the forward running example shown in Fig. 5B, the rotational speeds of the left and right sun gears S1, S2 are the same, but this is not limited to this. In other words, depending on the difference in rotational resistance between the right rear wheel 20R and the left rear wheel 20L, the distribution ratio of the motor drive force by the differential mechanism 22 changes, so it goes without saying that the rotational speeds of the left and right sun gears S1, S2 change, and the rotational speeds of the right rear wheel 20R and the left rear wheel 20L change.

[0024] <Coast driving> Next, coasting (deceleration) in which the accelerator pedal is released from acceleration or constant speed driving to gently decelerate the forward-traveling vehicle 11 will be described. Fig. 6A is a diagram showing the operating state of the electric axle 20 during coasting, and Fig. 6B is a collinear diagram showing the operating state of the electric axle 20 shown in Fig. 6A.

[0025] As shown in FIG. 6A, in coasting, the control system 60 controls the first and second clutch mechanisms CL1 and CL2 to be in a disengaged state, and controls the first and second brake mechanisms BR1 and BR2 to be in an engaged state. That is, in a state in which the right rear wheel 20R and the ring gear R1 are rotating in the forward direction (arrow a21 direction), the first clutch mechanism CL1 is disengaged and the first brake mechanism BR1 is engaged. This allows the carrier C1 to be stopped, and the sun gear S1 to be rotated in the backward direction (arrow a22 direction). In addition, in a state in which the left rear wheel 20L and the carrier C2 are rotating in the forward direction (arrow a23 direction), the second clutch mechanism CL2 is disengaged and the second brake mechanism BR2 is engaged. This allows the ring gear R2 to be stopped, and the sun gear S2 to be rotated in the forward direction (arrow a24 direction).

[0026] That is, as shown in FIG. 6B, the first planetary gear mechanism 23 has a structure in which the sun gear S1 and the ring gear R1 are arranged at both ends on the collinear diagram. The sun gear S1 of the first planetary gear mechanism 23 is connected to the first side gear 37, and the ring gear R1 of the first planetary gear mechanism 23 is connected to the right rear wheel 20R. The second planetary gear mechanism 24 has a structure in which the sun gear S2 and the ring gear R2 are arranged at both ends on the collinear diagram. The sun gear S2 of the second planetary gear mechanism 24 is connected to the second side gear 38, and the carrier C2 of the second planetary gear mechanism 24 is connected to the left rear wheel 20L. Since the planetary gear mechanisms 23 and 24 in the electric axle 20 are configured in this manner, the sun gears S1 and S2 can be rotated in opposite directions to each other by releasing the clutch mechanisms CL1 and CL2 and engaging the brake mechanisms BR1 and BR2 during coasting. This allows the rotations of the side gears 37, 38 to cancel each other out, reducing the rotation speed of the differential case 35 etc., thereby improving energy efficiency during coasting.

[0027] Moreover, the gear ratios of the first and second planetary gear mechanisms 23, 24 are set so that the absolute values ​​of the rotation speed Ns1 of the sun gear S1 and the rotation speed Ns2 of the sun gear S2 are equal to each other. That is, when the rotation speeds of the right rear wheel 20R and the left rear wheel 20L are equal to each other during coasting, that is, when the rotation speeds of the ring gear R1 and the carrier C2 are equal to each other, the rotation of the side gears 37, 38 can be completely cancelled. This makes it possible to stop the rotation of the differential case 35, the rotor 33, etc., and to suppress the rotation resistance of the electric axle 20 and significantly improve the energy efficiency of the vehicle 11. In the above description, the clutch mechanisms CL1, CL2 are released and the brake mechanisms BR1, BR2 are engaged during coasting when the accelerator pedal is released, but this is not limited to this, and the clutch mechanisms CL1, CL2 may be released and the brake mechanisms BR1, BR2 may be engaged during deceleration when the brake pedal is depressed.

[0028] <Turn Driving> The following describes turning travel selected by the driver's turn switch operation. Figure 7A is a diagram showing the operating state of the electric axle 20 during turning travel, and Figure 7B is a collinear diagram showing the operating state of the electric axle 20 shown in Figure 7A.

[0029] As shown in Fig. 7A, when turn running is selected by operating the turn switch, the control system 60 controls the first and second clutch mechanisms CL1 and CL2 to a disengaged state and controls the first and second brake mechanisms BR1 and BR2 to an engaged state with the right rear wheel 20R and the left rear wheel 20L stopped. That is, as shown in Fig. 7B, in the first planetary gear mechanism 23, since the carrier C1 is stopped, when the sun gear S1 rotates in the forward direction, the ring gear R1 rotates in the reverse direction, whereas when the sun gear S1 rotates in the reverse direction, the ring gear R1 rotates in the forward direction. In the second planetary gear mechanism 24, since the ring gear R2 is stopped, when the sun gear S2 rotates in the forward direction, the ring gear R1 rotates in the forward direction, whereas when the sun gear S1 rotates in the reverse direction, the ring gear R1 rotates in the reverse direction.

[0030] As described above, the first planetary gear mechanism 23 has a structure in which the sun gear S1 and the ring gear R1 are arranged at both ends on the collinear diagram. The sun gear S1 of the first planetary gear mechanism 23 is connected to the first side gear 37, and the ring gear R1 of the first planetary gear mechanism 23 is connected to the right rear wheel 20R. The second planetary gear mechanism 24 has a structure in which the sun gear S2 and the ring gear R2 are arranged at both ends on the collinear diagram. The sun gear S2 of the second planetary gear mechanism 24 is connected to the second side gear 38, and the carrier C2 of the second planetary gear mechanism 24 is connected to the left rear wheel 20L. Since the planetary gear mechanisms 23 and 24 in the electric axle 20 are configured in this manner, the ring gear R1 and the carrier C2 can be rotated in opposite directions to each other during turning by releasing the clutch mechanisms CL1 and CL2 and engaging the brake mechanisms BR1 and BR2.

[0031] As a result, as shown in FIG. 7A, when the motor generator 21 is driven in the forward direction (arrow a30 direction), the right rear wheel 20R can be rotated in the backward direction (arrow a31 direction), and the left rear wheel 20L can be rotated in the opposite forward direction (arrow a32 direction). When the motor generator 21 is driven in the backward direction (arrow b30 direction), the right rear wheel 20R can be rotated in the forward direction (arrow b31 direction), and the left rear wheel 20L can be rotated in the opposite backward direction (arrow b32 direction). In this way, since the right rear wheel 20R and the left rear wheel 20L can be rotated in opposite directions, it is possible to make a pivot turn of the vehicle 11 with the midpoint between the right rear wheel 20R and the left rear wheel 20L as the center of rotation. In other words, the vehicle 11 can be given a turning function while utilizing the differential mechanism 22.

[0032] Here, FIG. 8 is a diagram showing an example of a state in which turning is being performed. As shown in FIG. 8, with the right front wheel 92R and the left front wheel 92L steered, the right rear wheel 20R is rotated in the backward direction (arrow a31 direction) and the left rear wheel 20L is rotated in the forward direction (arrow a32 direction). This allows the vehicle 11 to pivot in a clockwise direction (arrow X2 direction) with the center between the right rear wheel 20R and the left rear wheel 20L as the rotation center X1. This makes it easy to turn the vehicle 11 in a narrow space, so that the driving operation of the vehicle 11 can be extremely simplified. It goes without saying that when the vehicle 11 is pivoted in a counterclockwise direction, the right rear wheel 20R is rotated in the forward direction and the left rear wheel 20L is rotated in the backward direction.

[0033] 7B, the gear ratios of the first and second planetary gear mechanisms 23, 24 are set so that the absolute values ​​of the rotational speed Nr1 of the ring gear R1 and the rotational speed Nc2 of the carrier C2 match each other. That is, when the rotational speeds of the side gears 37, 38 of the differential mechanism 22 match each other during turning, that is, when the rotational speeds of the sun gears S1, S2 match each other, the absolute values ​​of the rotational speed Nr1 of the ring gear R1 and the rotational speed Nc2 of the carrier C2 can be made to match each other. This makes it possible to suppress deviation of the rotation center X1 during a pivot turn, and to reduce the turning radius of the vehicle 11.

[0034] <Second embodiment> In the example shown in Fig. 1, the rear wheels are driven by the electric axle 20, but the present invention is not limited thereto, and the front wheels may be driven by the electric axle 20, or both the front and rear wheels may be driven by the electric axle 20. Here, Fig. 9 is a diagram showing an example of a vehicle 91 equipped with a vehicle drive device 90 according to another embodiment of the present disclosure. Fig. 10 is a diagram showing an example of a state in which the vehicle 91 is making a turn. In Figs. 9 and 10, the same members as those shown in Fig. 1 are denoted by the same reference numerals, and description thereof will be omitted.

[0035] 9, a vehicle 91 has an electric axle 92 that drives a right front wheel (first wheel) 92R and a left front wheel (second wheel) 92L, and an electric axle 20 that drives a right rear wheel 20R (first wheel) 30R and a left rear wheel 20L (second wheel) 30L. The electric axle 92 that drives the front wheels 92R, 92L has the same structure as the electric axle 20 described above.

[0036] As shown in FIG. 10, when the vehicle 91 is turned, the right front wheel 92R and the right rear wheel 20R are rotated in the backward direction (arrow a41 direction), and the left front wheel 92L and the left rear wheel 20L are rotated in the forward direction (arrow a42 direction). This allows the vehicle 91 to make a pivot turn, that is, a spin turn, clockwise (arrow X4 direction) with the midpoint between the right front wheel 92R and the left rear wheel 20L as the rotation center X3. This makes it easy to turn the vehicle 91 in a narrow space, so that the driving operation of the vehicle 91 can be extremely simplified. It goes without saying that when the vehicle 91 is turned in the counterclockwise direction, the right front wheel 92R and the right rear wheel 20R are rotated in the forward direction, and the left front wheel 92L and the left rear wheel 20L are rotated in the backward direction.

[0037] <Third embodiment> Fig. 11 is a diagram showing an electric axle 110 constituting a vehicle driving device 100 according to another embodiment of the present disclosure. In Fig. 11, the same components as those shown in Fig. 2 are denoted by the same reference numerals, and the description thereof will be omitted. Note that the electric axle 110 shown in Fig. 11 may drive either the front wheels or the rear wheels, or both the front wheels and the rear wheels may be driven by the electric axle 110 shown in Fig. 11.

[0038] As shown in FIG. 11, a differential mechanism 111 accommodated in an electric axle 110 includes a differential case 112 having a driven gear 34, a pinion 36 rotatably supported by the differential case 112, a first side gear 37 meshing with the pinion 36, and a second side gear 38 meshing with the pinion 36. The differential mechanism 111 also includes a viscous coupling 113 that limits the differential between the first side gear 37 and the differential case 112, that is, a viscous coupling 113 that limits the differential between the first side gear 37 and the second side gear 38. The viscous coupling 113 includes a clutch plate 114 attached to the output shaft 42 of the first side gear 37 and a clutch plate 115 attached to the inner circumferential surface of the differential case 112. The viscous coupling 113 also includes a coupling case 116 that accommodates the clutch plates 114, 115 arranged alternately. Furthermore, high viscosity silicone oil is sealed inside the coupling case 116.

[0039] Since silicone oil is sealed in the viscous coupling 113, when the rotational speed difference between the clutch plates 114, 115 increases, the silicone oil heats up, and the volume expansion of the silicone oil presses the clutch plates 114, 115 against each other. When the clutch plates 114, 115 are pressed against each other, a so-called hump phenomenon occurs, and the differential between the first side gear 37 and the second side gear 38 is limited. In other words, the viscous coupling 113 functions as a differential limiting clutch for the differential mechanism 111.

[0040] <Electric axle operation status> <Acceleration and constant speed driving> FIG. 12A is a diagram showing the operating state of the electric axle 110 during acceleration and constant speed running, and FIG. 12B is a collinear diagram showing the operating state of the electric axle 110 shown in FIG. 12A. As shown in FIG. 12A, during acceleration and constant speed running, the control system 60 controls the first and second brake mechanisms BR1 and BR2 to be in a released state, and controls the first and second clutch mechanisms CL1 and CL2 to be in an engaged state. In this way, by releasing the first brake mechanism BR1 and engaging the first clutch mechanism CL1, the respective rotating elements of the first planetary gear mechanism 23 can be rotated together, and the rotation of the first side gear 37 can be transmitted directly to the right rear wheel 20R. Similarly, by releasing the second brake mechanism BR2 and engaging the second clutch mechanism CL2, the respective rotating elements of the second planetary gear mechanism 24 can be rotated together, and the rotation of the second side gear 38 can be transmitted directly to the left rear wheel 20L. That is, as shown in FIG. 12B, the rotational speeds of the sun gear S1 and the ring gear R1 can be made to match each other, and the rotational speeds of the sun gear S2 and the carrier C2 can be made to match each other.

[0041] 12A, during forward travel, the motor generator 21 is driven in the forward direction (arrow a10 direction). This allows the motor driving force to be distributed to the left and right via the differential mechanism 111, and the right rear wheel 20R and the left rear wheel 20L can be rotated in the forward direction (arrow a11 direction, arrow a12 direction). On the other hand, during reverse travel, the motor generator 21 is driven in the reverse direction (arrow b10 direction). This allows the motor driving force to be distributed to the left and right via the differential mechanism 111, and the right rear wheel 20R and the left rear wheel 20L can be rotated in the reverse direction (arrow b11 direction, arrow b12 direction).

[0042] In the forward running example shown in Fig. 12B, the rotational speeds of the left and right sun gears S1, S2 are the same, but this is not limited to this. In other words, depending on the difference in rotational resistance between the right rear wheel 20R and the left rear wheel 20L, the distribution ratio of the motor driving force by the differential mechanism 111 changes, so it goes without saying that the rotational speeds of the left and right sun gears S1, S2 change, and the rotational speeds of the right rear wheel 20R and the left rear wheel 20L change. Also, if the state in which the rotational speed difference between the right rear wheel 20R and the left rear wheel 20L is large continues, the viscous coupling 113 is engaged, and the differential movement of the differential mechanism 111 is limited.

[0043] <Slowing down> Next, deceleration driving will be described in which the brake pedal is depressed during acceleration driving or constant speed driving to decelerate the vehicle 11 while it is moving forward. Fig. 13A is a diagram showing the operating state of the electric axle 110 during deceleration driving, and Fig. 13B is a collinear diagram showing the operating state of the electric axle 110 shown in Fig. 13A.

[0044] As shown in FIG. 13A, during deceleration, the control system 60 controls the first and second clutch mechanisms CL1 and CL2 to be in a released state, and controls the first and second brake mechanisms BR1 and BR2 to be in an engaged state. That is, in a state in which the right rear wheel 20R and the ring gear R1 are rotating in the forward direction (arrow a21 direction), the first clutch mechanism CL1 is released and the first brake mechanism BR1 is engaged. This allows the carrier C1 to be stopped, and the sun gear S1 to be rotated in the backward direction (arrow a22 direction). Also, in a state in which the left rear wheel 20L and the carrier C2 are rotating in the forward direction (arrow a23 direction), the second clutch mechanism CL2 is released and the second brake mechanism BR2 is engaged. This allows the ring gear R2 to be stopped, and the sun gear S2 to be rotated in the forward direction (arrow a24 direction).

[0045] That is, as shown in FIG. 13B, the first planetary gear mechanism 23 has a structure in which the sun gear S1 and the ring gear R1 are arranged at both ends on the collinear diagram. The sun gear S1 of the first planetary gear mechanism 23 is connected to the first side gear 37, and the ring gear R1 of the first planetary gear mechanism 23 is connected to the right rear wheel 20R. The second planetary gear mechanism 24 has a structure in which the sun gear S2 and the ring gear R2 are arranged at both ends on the collinear diagram. The sun gear S2 of the second planetary gear mechanism 24 is connected to the second side gear 38, and the carrier C2 of the second planetary gear mechanism 24 is connected to the left rear wheel 20L. Since the planetary gear mechanisms 23 and 24 in the electric axle 110 are configured in this manner, the sun gears S1 and S2 can be rotated in opposite directions to each other by releasing the clutch mechanisms CL1 and CL2 and engaging the brake mechanisms BR1 and BR2 during deceleration.

[0046] That is, during deceleration, the side gears 37, 38 rotate in opposite directions, so that a rotational speed difference can be generated in the clutch plates 114, 115 of the viscous coupling 113, and the silicone oil of the viscous coupling 113 can be expanded. In this way, by expanding the silicone oil during deceleration, the viscous coupling 113 can be quickly fastened during subsequent acceleration. For example, during acceleration at the start of a corner, it may be necessary to limit the differential of the differential mechanism 111 in order to improve acceleration performance. Even in such a case, by increasing the fastening force of the viscous coupling 113 during deceleration when entering a corner, the viscous coupling 113 can be quickly fastened when exiting the corner, thereby improving acceleration response.

[0047] In addition, since deceleration driving that does not require engagement of the viscous coupling 113 is also possible, the clutch mechanisms CL1 and CL2 may be released and the brake mechanisms BR1 and BR2 may be engaged during specific deceleration driving. For example, during deceleration driving in which a sports mode or the like that enhances the power performance of the vehicle 11 is selected, the clutch mechanisms CL1 and CL2 may be released and the brake mechanisms BR1 and BR2 may be engaged, whereas during deceleration driving in which a sports mode or the like is not selected, the brake mechanisms BR1 and BR2 may be released and the clutch mechanisms CL1 and CL2 may be maintained in an engaged state. In addition, when the vehicle deceleration during deceleration driving exceeds a threshold value, the clutch mechanisms CL1 and CL2 may be released and the brake mechanisms BR1 and BR2 may be engaged, whereas when the vehicle deceleration during deceleration driving falls below the threshold value, the brake mechanisms BR1 and BR2 may be released and the clutch mechanisms CL1 and CL2 may be maintained in an engaged state. In addition, during coast driving in which the accelerator pedal is released, the clutch mechanisms CL1 and CL2 may be released and the brake mechanisms BR1 and BR2 may be engaged.

[0048] <Turn Driving> The following describes turning travel selected by the driver's turn switch operation. Figure 14A is a diagram showing the operating state of the electric axle 110 during turning travel, and Figure 14B is a collinear diagram showing the operating state of the electric axle 110 shown in Figure 14A.

[0049] As shown in Fig. 14A, when turn running is selected by operating the turn switch, the control system 60 controls the first and second clutch mechanisms CL1 and CL2 to be released and the first and second brake mechanisms BR1 and BR2 to be engaged with the right rear wheel 20R and the left rear wheel 20L stopped. That is, as shown in Fig. 14B, in the first planetary gear mechanism 23, since the carrier C1 is stopped, when the sun gear S1 rotates in the forward direction, the ring gear R1 rotates in the reverse direction, whereas when the sun gear S1 rotates in the reverse direction, the ring gear R1 rotates in the forward direction. In the second planetary gear mechanism 24, since the ring gear R2 is stopped, when the sun gear S2 rotates in the forward direction, the ring gear R1 rotates in the forward direction, whereas when the sun gear S1 rotates in the reverse direction, the ring gear R1 rotates in the reverse direction.

[0050] As described above, the first planetary gear mechanism 23 has a structure in which the sun gear S1 and the ring gear R1 are arranged at both ends on the collinear diagram. The sun gear S1 of the first planetary gear mechanism 23 is connected to the first side gear 37, and the ring gear R1 of the first planetary gear mechanism 23 is connected to the right rear wheel 20R. The second planetary gear mechanism 24 has a structure in which the sun gear S2 and the ring gear R2 are arranged at both ends on the collinear diagram. The sun gear S2 of the second planetary gear mechanism 24 is connected to the second side gear 38, and the carrier C2 of the second planetary gear mechanism 24 is connected to the left rear wheel 20L. Since the planetary gear mechanism in the electric axle 110 is configured in this way, the ring gear R1 and the carrier C2 can be rotated in opposite directions to each other by releasing the clutch mechanisms CL1 and CL2 and engaging the brake mechanisms BR1 and BR2 during turning.

[0051] As a result, as shown in FIG. 14A, when the motor generator 21 is driven in the forward direction (arrow a30 direction), the right rear wheel 20R can be rotated in the backward direction (arrow a31 direction), and the left rear wheel 20L can be rotated in the opposite forward direction (arrow a32 direction). When the motor generator 21 is driven in the backward direction (arrow b30 direction), the right rear wheel 20R can be rotated in the forward direction (arrow b31 direction), and the left rear wheel 20L can be rotated in the opposite backward direction (arrow b32 direction). In this way, since the right rear wheel 20R and the left rear wheel 20L can be rotated in the opposite direction, it is possible to perform a pivot turn or a spin turn as shown in FIG. 8 or FIG. 10 described above. In other words, the vehicle 11, 91 can be given a turning function while utilizing the differential mechanism 111.

[0052] 14B, the gear ratios of the first and second planetary gear mechanisms 23, 24 are set so that the absolute values ​​of the rotational speed Nr1 of the ring gear R1 and the rotational speed Nc2 of the carrier C2 match each other. That is, when the rotational speeds of the side gears 37, 38 of the differential mechanism 111 match each other during turning, that is, when the rotational speeds of the sun gears S1, S2 match each other, the absolute values ​​of the rotational speed Nr1 of the ring gear R1 and the rotational speed Nc2 of the carrier C2 can be made to match each other. This makes it possible to suppress deviation of the rotation center during a spin turn or pivot turn, thereby reducing the turning radius of the vehicle 11, 91.

[0053] <Other embodiments> The present disclosure is not limited to the above-described embodiment, and may be modified in various ways without departing from the spirit of the present disclosure. In the example shown in FIG. 5A and FIG. 5B, the first planetary gear mechanism 23 has a structure in which the sun gear S1 and the ring gear R1 are arranged at both ends on the collinear diagram, but the present disclosure is not limited to this. For example, the first planetary gear mechanism 23 may have a structure in which the sun gear S1 and the carrier C1 are arranged at both ends on the collinear diagram, or may have a structure in which the ring gear R1 and the carrier C1 are arranged at both ends. That is, in the above description, the sun gear S1 is the first rotating element, the carrier C1 is the second rotating element, and the ring gear R1 is the third rotating element, but the present disclosure is not limited to this. For example, the sun gear S1 may be the second or third rotating element, the carrier C1 may be the first or third rotating element, and the ring gear R1 may be the first or second rotating element.

[0054] Similarly, in the example shown in FIG. 5A and FIG. 5B, the second planetary gear mechanism 24 has a structure in which the sun gear S2 and the ring gear R2 are arranged at both ends on the collinear diagram, but this is not limited thereto. For example, the second planetary gear mechanism 24 may have a structure in which the sun gear S2 and the carrier C2 are arranged at both ends on the collinear diagram, or may have a structure in which the ring gear R2 and the carrier C2 are arranged at both ends. That is, in the above description, the sun gear S2 is the fourth rotating element, the carrier C2 is the fifth rotating element, and the ring gear R2 is the sixth rotating element, but this is not limited thereto. For example, the sun gear S2 may be the fifth or sixth rotating element, the carrier C2 may be the fourth or sixth rotating element, and the ring gear R2 may be the fourth or fifth rotating element.

[0055] In the above description, single-pinion type planetary gear mechanisms are used as the first planetary gear mechanism 23 and the second planetary gear mechanism 24, but this is not limited thereto, and for example, double-pinion type planetary gear mechanisms may be used. In the above description, the motor generator 21 is used as the power source, but this is not limited thereto, and an internal combustion engine may be used as the power source. In addition, friction clutch mechanisms or mesh clutch mechanisms may be used as the first and second clutch mechanisms CL1 and CL2. In addition, friction brake mechanisms or mesh brake mechanisms may be used as the first and second brake mechanisms BR1 and BR2.

[0056] In the above description, the sun gear S1 and the carrier C1 are fastened together by the first clutch mechanism CL1, but this is not limited thereto, and the sun gear S1 and the ring gear R1 may be fastened together, or the carrier C1 and the ring gear R1 may be fastened together. In addition, the sun gear S1, the carrier C1 and the ring gear R1 may all be fastened together by the first clutch mechanism CL1. In the above description, the sun gear S2 and the ring gear R2 are fastened together by the second clutch mechanism CL2, but this is not limited thereto, and the sun gear S2 and the carrier C2 may be fastened together, or the ring gear R2 and the carrier C2 may be fastened together. In addition, the sun gear S2, the ring gear R2 and the carrier C2 may all be fastened together by the second clutch mechanism CL2.

[0057] The illustrated vehicles 11, 91 have front and rear wheels on the right side and front and rear wheels on the left side, but are not limited to this, and may have three or more wheels on the right side, or may have three or more wheels on the left side. In the above description, the control system 60 is configured by two control units 61, 70, but is not limited to this. For example, the control system 60 may be configured by one control unit, or may be configured by three or more control units. [Explanation of symbols]

[0058] 10...vehicle drive device, 20R...right rear wheel (first wheel), 20L...left rear wheel (second wheel), 21...motor generator (power source), 22...differential mechanism, 23...first planetary gear mechanism, 24...second planetary gear mechanism, 35...differential case, 37...first side gear, 38...second side gear, 41...first power transmission path, 51...second power transmission path, 60...control system, 80...processor, 81...main memory (memory), 90...vehicle drive device, 92R...right front wheel (first wheel), 92L ...Left front wheel (second wheel), 100...vehicle drive device, 111...differential mechanism, 112...differential case, 113...viscous coupling, S1...sun gear (first rotating element), C1...carrier (second rotating element), R1...ring gear (third rotating element), S2...sun gear (fourth rotating element), C2...carrier (fifth rotating element), R2...ring gear (sixth rotating element), CL1...first clutch mechanism, CL2...second clutch mechanism, BR1...first brake mechanism, BR2...second brake mechanism

Claims

1. A vehicle drive device that drives a first wheel and a second wheel, a differential mechanism including a differential case connected to a power source, a first side gear connected to the first wheel via a first power transmission path, and a second side gear connected to the second wheel via a second power transmission path; a first planetary gear mechanism provided in the first power transmission path and including a first rotating element, a second rotating element, and a third rotating element; a first clutch mechanism that fastens at least two of the first rotating element, the second rotating element, and the third rotating element to each other; a first brake mechanism that operates in a connected state to stop rotation of the second rotating element and in a released state to allow rotation of the second rotating element; a second planetary gear mechanism provided in the second power transmission path and including a fourth rotating element, a fifth rotating element, and a sixth rotating element; a second clutch mechanism that fastens at least two of the fourth rotating element, the fifth rotating element, and the sixth rotating element to each other; and a second brake mechanism that operates in a connected state to stop rotation of the sixth rotating element and in a released state to allow rotation of the sixth rotating element; having the first planetary gear mechanism has a structure in which the first rotating element and the third rotating element are disposed at both ends on a collinear diagram, the first rotating element is coupled to the first side gear, and the third rotating element is coupled to the first wheel; the second planetary gear mechanism has a structure in which the fourth rotating element and the sixth rotating element are disposed at both ends on a collinear diagram, the fourth rotating element is coupled to the second side gear, and the fifth rotating element is coupled to the second wheel; A drive unit for a vehicle.

2. 2. The vehicle drive device according to claim 1, a control system including a processor and a memory communicatively connected to each other, the control system controlling the first clutch mechanism, the second clutch mechanism, the first brake mechanism, and the second brake mechanism; The control system includes: When the first clutch mechanism and the second clutch mechanism are engaged, the first brake mechanism and the second brake mechanism are disengaged; when the first brake mechanism and the second brake mechanism are engaged, the first clutch mechanism and the second clutch mechanism are disengaged; A drive unit for a vehicle.

3. 2. The vehicle drive device according to claim 1, a control system including a processor and a memory communicatively connected to each other, the control system controlling the first clutch mechanism, the second clutch mechanism, the first brake mechanism, and the second brake mechanism; the control system disengages the first clutch mechanism and the second clutch mechanism and engages the first brake mechanism and the second brake mechanism under a condition in which the first wheel and the second wheel are stopped. A drive unit for a vehicle.

4. 2. The vehicle drive device according to claim 1, a control system including a processor and a memory communicatively connected to each other, the control system controlling the first clutch mechanism, the second clutch mechanism, the first brake mechanism, and the second brake mechanism; the control system disengages the first clutch mechanism and the second clutch mechanism and engages the first brake mechanism and the second brake mechanism when transitioning from accelerating travel or constant speed travel to decelerating travel. A drive unit for a vehicle.

5. 5. The vehicle drive device according to claim 4, The differential mechanism includes a viscous coupling that limits a differential motion between the first side gear and the second side gear. A drive unit for a vehicle.

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