Vehicular drive device

Abstract

To accomplish turning and vehicle height adjustment without mounting an actuator other than an electric motor that generates drive torque which rotates wheels.SOLUTION: A vehicular drive device includes: a first gear pair P1 that has a first gear G1 and a second gear G2 meshed with each other, the first gear being rotatable around a first axial line L1 and the second gear being rotatable around a second axial line L2; a second gear pair P2 that has a third gear G3 and a fourth gear G4 meshed with each other, the third gear being rotatable around the second axial line L2 and the fourth gear being rotatable around a third axial line L3; a first casing C1 that stores therein an electric motor 1; a second casing C2 which has the first gear pair P2 stored therein, and which is coupled to the first casing C1 so as to be rotatable around the first axial line L1; a third casing C3 which has the second gear pair P2 stored therein, and which is coupled to the second casing C2 so as to be rotatable around the second axial line L2; a first brake Br1 that can stop the rotation of the second casing C2; a second brake Br2 that can stop the rotation of the third casing C3; and a third brake Br3 that can stop the rotation of a third rotation axis A3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vehicle drive device that combines a vehicle height variation function and a wheel drive function. [Background technology]

[0002] Patent Document 1 discloses a vehicle drive device that includes an actuator for steering, separate from an in-wheel motor for driving the wheels. This vehicle drive device has a function for driving the wheels and a function for steering, but does not have a function for adjusting the vehicle height.

[0003] Patent Document 2 discloses a vehicle drive device that combines an in-wheel motor for driving the wheels with a link mechanism and can adjust the vehicle height using the in-wheel motor and link mechanism. This vehicle drive device has the function of driving the wheels and the function of adjusting the vehicle height, but does not have a steering function.

[0004] Patent Document 3 discloses a power transmission device including a first gear pair consisting of a first gear and a second gear that are rotatably arranged about intersecting first and second axes and mesh with each other, and a second gear pair consisting of a third gear and a fourth gear that are rotatably arranged about intersecting second and third axes, respectively, where the second and third gears are connected to rotate as a unit. This power transmission device includes a first gear case that houses the first gear pair and is rotatably connected to a base member about the first axis, and a second gear case that houses the second gear pair and is rotatably connected to the first gear case about the second axis. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-112112 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-241183 [Patent Document 3] Japanese Patent Application Publication No. 2019-163787 Summary of the Invention [Problem to be solved by the invention]

[0006] As disclosed in Patent Documents 1 and 2, there is known a vehicle drive system that includes an electric motor for driving each wheel. When adding a steering function and a vehicle height adjustment function to such a vehicle drive system, it is necessary to provide an actuator for each of the three functions of wheel drive, steering, and vehicle height adjustment. However, if an actuator is provided for each of the three functions, the space required to mount the vehicle drive system on the vehicle increases as the dimensions of the vehicle drive system increase, and power consumption increases.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a vehicle drive system that can achieve steering and vehicle height adjustment without mounting any actuator other than an electric motor that generates a drive torque to rotate the wheels. [Means for solving the problem]

[0008] A vehicle drive device according to the present invention includes an electric motor having a stator and a rotor, a first gear pair in which a first gear connected to the rotor via a first rotating shaft and rotating integrally with the rotor around a first axis, and a second gear arranged to be rotatable around a second axis perpendicular to the first axis, mesh with each other, a second gear pair in which a third gear connected to the second gear via a second rotating shaft and rotating integrally with the second gear around the second axis, and a fourth gear arranged to be rotatable around a third axis perpendicular to the second axis, mesh with each other, a third rotating shaft connecting the fourth gear to a wheel, and rotating integrally with the fourth gear and the wheel around the third axis, a first case that supports the stator and is fixed to a vehicle body, and a second gear pair in which a third gear connected to the second gear via a second rotating shaft and rotating integrally with the second gear around the second axis, and a fourth gear arranged to be rotatable around a third axis perpendicular to the second axis, mesh with each other, a third rotating shaft that connects the fourth gear to a wheel, and rotates integrally with the fourth gear and the wheel around the third axis, a a second case rotatably connected to the first case about the first axis; a third case rotatably connected to the second case about the second axis; a first brake capable of stopping the rotation of the second case; a second brake capable of stopping the rotation of the third case; a third brake capable of stopping the rotation of the third case; a steering angle sensor capable of monitoring the rotation angle of the third case; and a vehicle height fluctuates due to the rotation of the second case, and a steering angle of the wheels fluctuates due to the rotation of the third case.

[0009] In one aspect of the vehicle drive device according to the present invention, a fifth bearing that rotatably supports the second case and the first brake may be provided on the first case.

[0010] In one aspect of the vehicle drive device according to the present invention, a sixth bearing that rotatably supports the third case and the second brake may be provided on the second case.

[0011] In one aspect of the vehicle drive device according to the present invention, a brake disc may be fixed to the third rotating shaft, and the third brake may be able to stop rotation of the third rotating shaft by coming into contact with the brake disc.

[0012] In one aspect of the vehicle drive device according to the present invention, the steering angle sensor may be provided in the second case.

[0013] In one aspect of the vehicle drive device according to the present invention, an inverter for the electric motor and a battery may be housed in the first case.

[0014] In one aspect of the vehicle drive device according to the present invention, an inverter and a battery for the electric motor may be mounted on the vehicle body. [Effects of the Invention]

[0015] The present invention can provide a vehicle drive system that can achieve steering and vehicle height adjustment without mounting any actuator other than an electric motor that generates drive torque to rotate the wheels. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a cross-sectional view showing a configuration of a vehicle drive device according to an embodiment of the present disclosure. [Figure 2] 1 is a cross-sectional view showing an exploded state of a vehicle drive device according to an embodiment of the present invention. [Figure 3] 3 is a cross-sectional view taken along the line AA in FIG. 2. [Figure 4] 3 is a cross-sectional view of FIG. 2 taken along line B-B. [Figure 5] 3 is a cross-sectional view taken along CC in FIG. 2. [Figure 6] 1 is a perspective view of a vehicle in which a vehicle drive device of the present embodiment is provided for each of four wheels. [Figure 7] 1 is a table showing the operation of the electric motor and the first to third brakes when the vehicle stops, moves straight, changes vehicle height, and changes direction. [Figure 8] FIG. 2 is a top view of the vehicle traveling straight ahead. [Figure 9] FIG. 2 is a side view of the vehicle with the vehicle height at its highest position. [Figure 10] FIG. 1 is a side view of a vehicle with its vehicle height lowered. [Figure 11] FIG. 1 is a top view of a vehicle turning in place. [Figure 12] 10 is a table showing the operation of the electric motor and the first to third brakes when traveling while making large turns. [Figure 13] FIG. 1 is a top view of a vehicle traveling while making a large turn to the left. [Figure 14] FIG. 1 is a top view of a vehicle traveling while making a large turn to the right. [Figure 15] 10 is a table showing the operation of the electric motor and the first to third brakes when making a small turn while traveling. [Figure 16] FIG. 1 is a top view of a vehicle making a small turn to the left while traveling. [Figure 17] FIG. 1 is a top view of a vehicle making a small turn to the right while traveling. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, a vehicle drive device 10 of this embodiment will be described with reference to Figures 1 to 17. Figure 1 is a cross-sectional view showing the configuration of the vehicle drive device 10. The vehicle drive device 10 shown in Figure 1 is a drive device for one wheel. Therefore, for example, in a vehicle with four wheels, one vehicle drive device 10 will be installed for each of the four wheels.

[0018] 1, the vehicle drive system 10 includes an electric motor 1, a first rotating shaft A1, a first gear pair P1, a second rotating shaft A2, a second gear pair P2, and a third rotating shaft A3. The vehicle drive system 10 can transmit the drive torque of the first rotating shaft A1, which is the output shaft of the electric motor 1, to wheels via the first gear pair P1, the second rotating shaft A2, the second gear pair P2, and the third rotating shaft A3.

[0019] Fig. 2 is a cross-sectional view showing an exploded state of the vehicle drive device 10. Fig. 3 is a cross-sectional view taken along line AA in Fig. 2. As shown in Fig. 3, the electric motor 1 includes a stator 11 and a rotor 12.

[0020] Fig. 4 is a cross-sectional view taken along the line BB in Fig. 2. As shown in Fig. 1 and Fig. 4, the first gear pair P1 is composed of a first gear G1 that is connected to the rotor 12 via a first rotation axis A1 and rotates integrally with the rotor 12 about a first axis L1, and a second gear G2 that is arranged rotatable about a second axis L2 that is perpendicular to the first axis L1 and meshes with the first gear G1. The first gear pair P1 is a reduction gear pair, and the rotational speed of the second gear G2 is slower than the rotational speed of the first gear G1.

[0021] 1, the second gear pair P2 is composed of a third gear G3 that is connected to the second gear G2 via the second rotation axis A2 and rotates integrally with the second gear G2 about the second axis L2, and a fourth gear G4 that is rotatable about a third axis L3 that is perpendicular to the second axis L2 and meshes with the third gear G3. The second gear pair P2 is a reduction gear pair, and the rotational speed of the fourth gear G4 is slower than the rotational speed of the third gear G3.

[0022] The third rotation shaft A3 is connected to the fourth gear G4 and rotates integrally with the fourth gear G4 about the third axis L3. By connecting the right end of the third rotation shaft A3 in FIG. 1 to a wheel, the third rotation shaft A3 can rotate integrally with the wheel about the third axis L3.

[0023] The vehicle drive device 10 includes a first case C1, a second case C2, and a third case C3. The first case C1 houses the electric motor 1 while supporting the stator 11. As shown in FIG. 1, the first case C1 may also house an inverter 13 and a battery 14 for the electric motor 1. As shown in FIGS. 1 and 2, the first case C1 is composed of a first case main body C1a and a first case cover C1b. The first case main body C1a has an attachment surface 21 that can be fixed to a vehicle body 2. The first case main body C1a is fixed to the vehicle body 2 with fastening elements such as bolts while the attachment surface 21 is in contact with the vehicle body 2. The first case cover C1b is fixed to the first case main body C1a with fastening elements such as bolts.

[0024] As shown in FIG. 1, the second case C2 houses the first gear pair P1. The second case C2 includes a first bearing B1 that rotatably supports the first rotating shaft A1 and a second bearing B2 that rotatably supports the second rotating shaft A2. As shown in FIGS. 1 and 2, the second case C2 is composed of a second case body C2a and a second case cover C2b. The second case cover C2b is fixed to the second case body C2a with fastening elements such as bolts. The second case cover C2b is provided with the steering angle sensor 4. The second case body C2a includes a cylindrical portion C2c. The cylindrical portion C2c is inserted into the first case cover C1b and rotatably supported by a fifth bearing B5 provided in the first case cover C1b. The central axis of the fifth bearing B5 coincides with the first axis L1, which is the rotational axis of the first rotating shaft A1. In this way, the cylindrical portion C2c of the second case C2 is inserted into the first case C1, and the cylindrical portion C2c is rotatably supported by the fifth bearing B5 provided in the first case C1, so that the second case C2 is connected to the first case C1 so as to be rotatable around the first axis L1.

[0025] FIG. 5 is a cross-sectional view taken along CC in FIG. 2. As shown in FIGS. 1 and 5, the third case C3 houses the second gear pair P2. As shown in FIGS. 1 and 2, the third case C3 includes a third bearing B3 that rotatably supports the second rotation shaft A2 and a fourth bearing B4 that rotatably supports the third rotation shaft A3. The third case C3 is composed of a third case body C3a and a third case cover C3b. The third case cover C3b is fixed to the third case body C3a with fastening elements such as bolts. The third case body C3a is provided with a cylindrical portion C3c. The cylindrical portion C3c is inserted into the second case cover C2b and rotatably supported by a sixth bearing B6 provided in the second case cover C2b. The central axis of the sixth bearing B6 coincides with the second axis L2, which is the rotation axis of the second rotation shaft A2. In this way, the cylindrical portion C3c of the third case C3 is inserted into the second case C2, and the cylindrical portion C3c is rotatably supported by the sixth bearing B6 provided in the second case C2, so that the third case C3 is connected to the second case C2 so as to be rotatable around the second axis L2.

[0026] Slit-shaped grooves are formed at regular intervals on the outer peripheral surface of the cylindrical portion C3c. A steering angle sensor 4 provided on the second case cover C2b detects the grooves formed on the outer peripheral surface of the cylindrical portion C3c and converts it into a rotation angle of the third case C3. The vehicle drive device 10 controls the direction in which the wheels roll by monitoring the rotation angle of the third case C3, i.e., the steering angle, with the steering angle sensor 4.

[0027] As shown in Fig. 1, the vehicle drive device 10 includes a first brake Br1, a second brake Br2, and a third brake Br3. The first brake Br1 is provided on the first case cover C1b. The first brake Br1 comes into contact with the outer peripheral surface of the cylindrical portion C2c of the second case C2, thereby stopping rotation of the second case C2 about the first axis L1. The first brake Br1 may include, for example, two arc-shaped brake pads, and may have a structure in which the outer peripheral surface of the cylindrical portion C2c of the second case C2 is sandwiched between the two brake pads from above and below.

[0028] The second brake Br2 is provided on the second case cover C2b. The second brake Br2 comes into contact with the outer peripheral surface of the cylindrical portion C3c of the third case C3 to stop rotation of the third case C3 about the second axis L2. The second brake Br2 may have, for example, two arc-shaped brake pads that sandwich the outer peripheral surface of the cylindrical portion C3c of the third case C3 from both the left and right sides.

[0029] The third brake Br3 is provided on the third case cover C3b. A brake disc 5 is fixed to the third rotating shaft A3, and the brake disc 5 rotates integrally with the third rotating shaft A3. The third brake Br3 has a hollow disk shape, and can stop the rotation of the third rotating shaft A3 by pressing a brake pad against one side of the brake disc 5. Note that the third brake Br3 may also have a structure in which the outer periphery of the brake disc 5 is sandwiched between brake pads from the front and back.

[0030] 6 is a perspective view of a vehicle 7 in which one vehicle drive device 10 is provided for each of the right front wheel 6a, left front wheel 6b, right rear wheel 6c, and left rear wheel 6d. The vehicle drive device 10 can vary the vehicle height of the vehicle 7 by rotating the second case C2. The vehicle drive device 10 can vary the steering angle of the wheels 6a to 6d by rotating the third case C3.

[0031] FIG. 7 is a table showing the operation of each element of the electric motor 1, the first brake Br1, the second brake Br2, and the third brake Br3 when the vehicle 7 stops, moves straight, changes vehicle height, and changes direction.

[0032] When stopping the vehicle 7, for all vehicle drive devices 10 for the wheels 6a to 6d, the electric motors 1 are stopped, the first brake Br1 and the third brake Br3 are turned ON, and the second brake Br2 is turned ON or OFF, as shown in Fig. 7. In this state, the first brake Br1 stops the rotation of the first case C1, thereby maintaining the vehicle height, and the third brake Br3 stops the rotation of the third rotation shaft A3 about the third axis L3, thereby stopping the rotation of the wheels 6a to 6d. Therefore, the vehicle height is maintained when the vehicle 7 is stopped.

[0033] FIG. 8 is a top view of the vehicle 7 traveling straight. When the vehicle 7 travels straight, as shown in FIG. 7, the electric motors 1 are driven for all of the vehicle drive devices 10 for the wheels 6a to 6d, the first brake Br1 and the second brake Br2 are turned ON, and the third brake Br3 is turned OFF. In this state, the first brake Br1 stops the rotation of the first case C1, thereby maintaining the vehicle height. The second brake Br2 stops the rotation of the second case C2, thereby maintaining the steering angle in the direction of straight travel. The driving torque of the electric motor 1 is then transmitted to the third rotation shaft A3 via the first rotation shaft A1, the first gear pair P1, the second rotation shaft A2, and the second gear pair P2, causing the wheels 6a to 6d to rotate. As a result, the vehicle 7 travels straight, as shown in FIG. 8, with the steering angle maintained in the direction of straight travel and the vehicle height maintained.

[0034] When changing the vehicle height while the vehicle 7 is stopped, the electric motor 1 is driven for all of the vehicle drive devices 10 for the wheels 6a to 6d, the first brake Br1 is turned OFF, and the second brake Br2 and the third brake Br3 are turned ON, as shown in Fig. 7. In this state, the third brake Br3 stops the rotation of the third rotating shaft A3 about the third axis L3. Furthermore, the second brake Br2 stops the rotation of the third case C3 and the third rotating shaft A3 about the second axis L2, so the third gear G3, which meshes with the fourth gear G4 in the second gear pair P2, and the second rotating shaft A2 and second gear G2, which are connected to the third gear G3, cannot rotate about the second axis L2. In this manner, while the second gear G2 and the second rotating shaft A2 cannot rotate about the second axis L2, the first gear G1 is rotated by the electric motor 1, and the meshing position of the first gear G1 and the second gear G2 in the first gear pair P1 changes in the circumferential direction of the first gear G1. As the meshing position of the first gear G1 changes in the circumferential direction of the first gear G1, the second gear G2 and the second rotating shaft A2 rotate about the first axis L1, and the second case C2, which supports the second rotating shaft A2 via the second bearing B2, rotates about the first axis L1. As a result of the second case C2 rotating about the first axis L1 in this manner, the vehicle height of the vehicle 7 fluctuates. FIG. 9 is a side view of the vehicle 7 with its vehicle height set to its highest position so that the minimum ground clearance H is maximized. FIG. 10 is a side view of the vehicle 7 with its vehicle height lowered so that the minimum ground clearance H is reduced.

[0035] 11 is a top view of the vehicle 7 while it is turning on the spot. When turning the vehicle 7 on the spot, as a first step, for all of the vehicle drive devices 10 for the wheels 6a to 6d, the electric motors 1 are driven, the first brakes Br1 are turned ON, the second brakes Br2 are turned OFF, and the third brakes Br3 are turned ON until a predetermined steering angle is reached. Then, the detection value of the steering angle sensor 4 is monitored, and once the predetermined steering angle is reached, as a second step, for all of the vehicle drive devices 10 for the wheels 6a to 6d, the electric motors 1 are driven, the first brakes Br1 are kept ON, the second brakes Br2 are turned ON, and the third brakes Br3 are turned OFF.

[0036] In the first step, the first brake Br1 stops the rotation of the first case C1, thereby maintaining the vehicle height. Then, the electric motor 1 is driven, causing the first rotating shaft A1 and the first gear G1 to rotate about the first axis L1. This causes the second gear G2, which meshes with the first gear G1 in the first gear pair P1, and the second rotating shaft A2 and third gear G3, which are connected to the second gear G2, to rotate about the second axis L2. However, the third brake Br3 stops the rotation of the third rotating shaft A3 and the fourth gear G4 about the third axis L3. Because the third gear G3 rotates while the fourth gear G4 and the third rotating shaft A3 cannot rotate about the third axis L3, the meshing position of the third gear G3 and the fourth gear G4 in the second gear pair P2 changes circumferentially around the third gear G3. Then, as the meshing position of the third gear G3 changes in the circumferential direction of the third gear G3, the fourth gear and the third rotating shaft A3 rotate about the second axis L2, and the third case C3, which supports the third rotating shaft A3 by the fourth bearing B4, rotates about the second axis L2. As a result of the third case C3 rotating about the second axis L2 in this manner, the steering angle can be changed. The first step continues until the predetermined steering angle is reached.

[0037] In the second step after the predetermined steering angle is reached, the third brake Br3 is disengaged. This transmits the drive torque of the electric motor 1 to the third rotating shaft A3 via the first rotating shaft A1, the first gear pair P1, the second rotating shaft A2, and the second gear pair P2, causing the wheels 6a to 6d to rotate. To rotate the vehicle 7 in the direction shown in FIG. 11 , the wheels 6a and 6c generate drive torque from the electric motor 1 in the same direction when moving the vehicle 7 forward, and the wheels 6b and 6d generate drive torque from the electric motor 1 in the same direction when moving the vehicle 7 backward. The first brake Br1 stops the rotation of the first case C1, thereby maintaining the vehicle height. The second brake Br2 stops the rotation of the second case C2, thereby maintaining the steering angle. This allows the vehicle 7 to change direction on the spot, as shown in FIG. 11 .

[0038] In this way, the vehicle drive system 10 can drive the wheels 6a to 6d by turning on the first brake Br1 and the second brake Br2 and turning off the third brake Br3 while the electric motor 1 is driven. The vehicle drive system 10 can also steer the wheels 6a to 6d by turning on the first brake Br1 and the third brake Br3 and turning off the second brake Br2 while the electric motor 1 is driven. Furthermore, the vehicle drive system 10 can vary the vehicle height by turning off the first brake Br1 and turning on the second brake Br2 and the third brake Br3 while the electric motor 1 is driven. In this way, the vehicle drive system 10 can achieve steering and vehicle height adjustment without installing any actuators other than the electric motor 1 that rotates the wheels 6a to 6d by switching the operation of the first brake Br1, the second brake Br2, and the third brake Br3 while the electric motor 1 is driven.

[0039] Next, we will explain the operations of the electric motor 1, the first brake Br1, the second brake Br2, and the third brake Br3 when the vehicle 7 is traveling while turning. Fig. 12 is a table showing the operations of the electric motor 1, the first brake Br1, the second brake Br2, and the third brake Br3 when traveling while making a large turn, such as turning left or right at an intersection.

[0040] Fig. 13 is a top view of the vehicle 7 when traveling while making a large turn to the left. When traveling while making a large turn to the left, as shown in Fig. 12, for the vehicle drive device 10 for the right front wheel 6a, the electric motor 1 is driven to turn the first brake Br1 ON and the third brake Br3 OFF, and the second brake Br2 is OFF until the steering angle of the right front wheel 6a reaches a set value. Then, for the vehicle drive device 10 for the left front wheel 6b, the electric motor 1 stops outputting torque and turns the first brake Br1 ON, and the second brake Br2 is OFF and the third brake Br3 is ON until the steering angle of the left front wheel 6b reaches a set value.

[0041] The detection value of the steering angle sensor 4 is monitored, and when the steering angle of the right front wheel 6a reaches a set value, the second brake Br2 of the vehicle drive device 10 for the right front wheel 6a is turned ON, and when the steering angle of the left front wheel 6b reaches a set value, the second brake Br2 of the vehicle drive device 10 for the left front wheel 6b is turned ON and the third brake Br3 is turned OFF. During a left turn, the electric motor 1 of the vehicle drive device 10 for the left front wheel 6b enters a regenerative state in which the rotation of the rotor 12 is decelerated. By operating the electric motor 1, the first brake Br1, the second brake Br2, and the third brake Br3 for the vehicle drive device 10 for the right front wheel 6a and the vehicle drive device 10 for the left front wheel 6b in this way, the steering angles of the right front wheel 6a and the left front wheel 6b become the states shown in FIG. 13, and the vehicle 7 makes a large turn to the left while traveling at a low speed.

[0042] Fig. 14 is a top view of the vehicle 7 when traveling while making a large turn to the right. When traveling while making a large turn to the right, as shown in Fig. 12, for the vehicle drive device 10 for the right front wheel 6a, the electric motor 1 stops outputting torque, the first brake Br1 is turned ON, the second brake Br2 is turned OFF, and the third brake Br3 is turned ON until the steering angle of the right front wheel 6a reaches a set value. Then, for the vehicle drive device 10 for the left front wheel 6b, the electric motor 1 is driven to turn the first brake Br1 ON, the third brake Br3 is turned OFF, and the second brake Br2 is turned OFF until the steering angle of the left front wheel 6b reaches a set value.

[0043] The detection value of the steering angle sensor 4 is monitored, and when the steering angle of the right front wheel 6a reaches a set value, the second brake Br2 of the vehicle drive device 10 for the right front wheel 6a is turned ON, and when the steering angle of the left front wheel 6b reaches a set value, the second brake Br2 of the vehicle drive device 10 for the left front wheel 6b is turned ON and the third brake Br3 is turned OFF. During a turn to the right, the electric motor 1 of the vehicle drive device 10 for the right front wheel 6a enters a regenerative state in which the rotation of the rotor 12 is decelerated. By operating the electric motor 1, first brake Br1, second brake Br2, and third brake Br3 for the vehicle drive devices 10 for the right front wheel 6a and the left front wheel 6b in this way, the right front wheel 6a and the left front wheel 6b enter the states shown in FIG. 14, and the vehicle 7 makes a large turn to the right while traveling at a low speed.

[0044] FIG. 15 is a table showing the operations of the electric motor 1, the first brake Br1, the second brake Br2, and the third brake Br3 when making a small turn while traveling, such as when changing lanes.

[0045] FIG. 16 is a top view of the vehicle 7 when making a small turn to the left while traveling. When making a small turn to the left while traveling, as shown in FIG. 15, for the vehicle drive devices 10 for the right front wheel 6a and the right rear wheel 6c, a large drive torque is generated in the electric motor 1 to turn on the first brake Br1 and the second brake Br2 and turn off the third brake Br3. Then, for the vehicle drive devices 10 for the left front wheel 6b and the left rear wheel 6d, a small drive torque is generated in the electric motor 1 to turn on the first brake Br1 and the second brake Br2 and turn off the third brake Br3. By operating the electric motors 1, first brake Br1, second brake Br2, and third brake Br3 of the vehicle drive devices 10 for the wheels 6a to 6d in this manner, a yawing moment is generated in the vehicle 7, causing the vehicle 7 to make a small turn to the left as shown in FIG. 16.

[0046] FIG. 17 is a top view of the vehicle 7 when making a small turn to the right while traveling. When making a small turn to the right while traveling, as shown in FIG. 15, for the vehicle drive devices 10 for the right front wheel 6a and the right rear wheel 6c, a small drive torque is generated in the electric motor 1 to turn on the first brake Br1 and the second brake Br2 and turn off the third brake Br3. Then, for the vehicle drive devices 10 for the left front wheel 6b and the left rear wheel 6d, a large drive torque is generated in the electric motor 1 to turn on the first brake Br1 and the second brake Br2 and turn off the third brake Br3. By operating the electric motors 1, first brake Br1, second brake Br2, and third brake Br3 of the vehicle drive devices 10 for the wheels 6a to 6d in this manner, a yawing moment is generated in the vehicle 7, causing the vehicle 7 to make a small turn to the right as shown in FIG. 17.

[0047] In this way, the vehicle drive device 10 can realize the following operations of the vehicle 7: stopping, moving straight, changing vehicle height, changing direction on the spot, and turning left and right while driving, by switching the operation of the electric motor 1, the first brake Br1, the second brake Br2, and the third brake Br3.

[0048] <Supplementary information on the embodiment> The vehicle drive device of the present invention is not limited to the above-described embodiment and can be embodied in various forms within the scope of the present invention. For example, the inverter 13 and the battery 14 for the electric motor 1 may be mounted on the vehicle body 2 instead of being housed in the first case C1.

[0049] [Configuration of the invention] [Configuration 1] an electric motor comprising a stator and a rotor; a first gear pair in which a first gear is connected to the rotor via a first rotation shaft and rotates integrally with the rotor about a first axis, and a second gear is disposed rotatable about a second axis perpendicular to the first axis, and the first gear pair meshes with each other; a second gear pair in which a third gear that is connected to the second gear via a second rotation shaft and rotates integrally with the second gear about the second axis line and a fourth gear that is arranged rotatable about a third axis line perpendicular to the second axis line are meshed with each other; a third rotation shaft that connects the fourth gear and a wheel and rotates integrally with the fourth gear and the wheel about the third axis; a first case that houses the electric motor while supporting the stator and is fixed to a vehicle body; a second case that houses the first gear pair and includes a first bearing that rotatably supports the first rotating shaft and a second bearing that rotatably supports the second rotating shaft, and is coupled to the first case so as to be rotatable about the first axis; a third case that houses the second gear pair and includes a third bearing that rotatably supports the second rotation shaft and a fourth bearing that rotatably supports the third rotation shaft, and is coupled to the second case so as to be rotatable about the second axis; a first brake capable of stopping the rotation of the second case; a second brake capable of stopping the rotation of the third case; a third brake capable of stopping the rotation of the third rotation shaft; a steering angle sensor capable of monitoring the rotation angle of the third case, A vehicle drive device, wherein the vehicle height varies with the rotation of the second case, and the steering angle of the wheels varies with the rotation of the third case. [Configuration 2] The vehicle drive device according to configuration 1, The vehicle drive device, wherein the first case is provided with a fifth bearing that rotatably supports the second case, and the first brake. [Configuration 3] The vehicle drive device according to the first or second aspect, A vehicle drive device, wherein the second case is provided with a sixth bearing that rotatably supports the third case, and the second brake. [Configuration 4] The vehicle drive device according to any one of configurations 1 to 3, A vehicle drive device, characterized in that a brake disc is fixed to the third rotating shaft, and the third brake can stop rotation of the third rotating shaft by contacting the brake disc. [Configuration 5] A vehicle drive device according to any one of configurations 1 to 4, The vehicle drive device, wherein the steering angle sensor is provided in the second case. [Configuration 6] A vehicle drive device according to any one of configurations 1 to 5, A vehicle drive device, wherein an inverter for the electric motor and a battery are housed in the first case. [Configuration 7] The vehicle drive device according to any one of configurations 1 to 5, A vehicle drive system, characterized in that an inverter for the electric motor and a battery are mounted on the vehicle body. [Explanation of symbols]

[0050] 1 electric motor, 2 vehicle body, 4 steering angle sensor, 5 brake disc, 6a right front wheel, 6b left front wheel, 6c right rear wheel, 6d left rear wheel, 7 vehicle, 10 vehicle drive device, 11 stator, 12 rotor, 13 inverter, 14 battery, 21 mounting surface, A1 first rotating shaft, A2 second rotating shaft, A3 third rotating shaft, B1 first bearing, B2 second bearing, B3 third bearing, B4 fourth bearing, B5 fifth bearing, B6 sixth bearing, Br1 first brake, Br2 second brake, Br3 third brake, C1 first case, C1a first case body, C1b first case cover, C2 second case, C2a second case body, C2b second case cover, C2c cylindrical portion, C3 third case, C3a third case body, C3b third case cover, C3c Cylindrical portion, G1 first gear, G2 second gear, G3 third gear, G4 fourth gear, L1 first axis, L2 second axis, L3 third axis, P1 first gear pair, P2 second gear pair.

Claims

1. an electric motor comprising a stator and a rotor; a first gear pair in which a first gear is connected to the rotor via a first rotation shaft and rotates integrally with the rotor about a first axis, and a second gear is disposed rotatable about a second axis perpendicular to the first axis, and the first gear pair meshes with each other; a second gear pair in which a third gear connected to the second gear via a second rotation shaft and rotating integrally with the second gear about the second axis and a fourth gear arranged rotatable about a third axis perpendicular to the second axis are meshed with each other; a third rotation shaft that connects the fourth gear and a wheel and rotates integrally with the fourth gear and the wheel about the third axis; a first case that houses the electric motor while supporting the stator and is fixed to a vehicle body; a second case that houses the first gear pair and includes a first bearing that rotatably supports the first rotation shaft and a second bearing that rotatably supports the second rotation shaft, the second case being coupled to the first case so as to be rotatable about the first axis; a third case that houses the second gear pair and includes a third bearing that rotatably supports the second rotation shaft and a fourth bearing that rotatably supports the third rotation shaft, and is coupled to the second case to be rotatable about the second axis; a first brake capable of stopping the rotation of the second case; a second brake capable of stopping the rotation of the third case; a third brake capable of stopping the rotation of the third rotation shaft; a steering angle sensor capable of monitoring the rotation angle of the third case, A vehicle drive device, wherein the vehicle height is changed by rotation of the second case, and the steering angle of the wheels is changed by rotation of the third case.

2. 2. The vehicle drive device according to claim 1, a fifth bearing that rotatably supports the second case, and the first brake are provided on the first case.

3. 3. The vehicle drive device according to claim 2, a sixth bearing that rotatably supports the third case, and the second brake are provided on the second case.

4. 4. The vehicle drive device according to claim 3, A vehicle drive device, characterized in that a brake disc is fixed to the third rotating shaft, and the third brake can stop rotation of the third rotating shaft by contacting the brake disc.

5. The vehicle drive device according to any one of claims 1 to 4, The vehicle drive device, wherein the steering angle sensor is provided in the second case.

6. 6. The vehicle drive device according to claim 5, a first case for housing an inverter for the electric motor and a battery;

7. 6. The vehicle drive device according to claim 5, A vehicle drive system, characterized in that an inverter for the electric motor and a battery are mounted on the vehicle body.

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