Drive device for four-wheel drive vehicle

Abstract

The present invention relates to and provides a drive device for a four-wheel drive vehicle that can maximize the output of an electric motor and drive the electric motor with high efficiency. The drive device for the four-wheel drive vehicle includes: a first clutch mechanism that switches the connection or disconnection of the power transmission system on the front-wheel side and the power transmission system on the rear-wheel side; a first electric motor that is connected to either the front-wheel side or the rear-wheel side, which is closer to the front wheels than the first clutch mechanism; a second electric motor that is connected to the other side of the front-wheel side or the rear-wheel side, which is closer to the front wheels than the first clutch mechanism; a second clutch mechanism that switches the connection or disconnection of the first electric motor and the drive shaft on the front-wheel side; a planetary gear mechanism that distributes the output of the first electric motor to the first clutch mechanism side and the second clutch mechanism side; and a third clutch mechanism that restricts the differential between the rotating elements on the first clutch mechanism side and the rotating elements on the second clutch mechanism side of the planetary gear mechanism.

Description

Technical Field

[0001] The present invention relates to a drive device for a four-wheel drive vehicle with an electric motor. Background Art

[0002] In recent years, the development of four-wheel drive electric vehicles that use the output of an electric motor as a driving force has been underway. As a driving method for a four-wheel drive vehicle with an electric motor, for example, an in-wheel motor method in which a driving motor is provided on each wheel and a method in which the output of an electric motor is transmitted to each wheel via a power transmission mechanism are exemplified. For example, a four-wheel drive vehicle with an in-wheel motor method is disclosed in Patent Document 1. In addition, a four-wheel drive vehicle with a dual-motor method in which two driving motors are respectively responsible for driving the front wheels and the rear wheels is disclosed in Patent Document 2.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2016-92995

[0006] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2018-70076 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] However, in the four-wheel drive vehicles described in Patent Documents 1 and 2, since at least the power transmission mechanism for driving force is mechanically separated into the front wheel side and the rear wheel side, when attempting to drive either the front wheels or the rear wheels, the output of all the electric motors cannot be utilized to the maximum extent. For example, when the rear wheels get stuck in mud or the like and spin, in order to get the vehicle out, even if a large driving force is required on the front wheel side, since the output of the electric motor for driving the rear wheels cannot be transmitted to the front wheel side, all the driving force of the electric motors cannot be used.

[0009] In addition, when the power transmission mechanism for driving force is separated into the front wheel side and the rear wheel side, at least the rotation or torque synchronization of the front wheels and the rear wheels must be electronically controlled. Therefore, the responsiveness may decrease. Moreover, since conventional electric vehicles have a structure in which an electric motor and a wheel are connected via a speed reducer, it is difficult to perform driving or regeneration aiming at the efficiency point of the electric motor.

[0010] The present invention has been made in view of the above problems, and an object of the present invention is to provide a drive device for a four-wheel drive vehicle that can maximize the output of an electric motor and can drive the electric motor with high efficiency.

[0011] Means for Solving the Problems

[0012] In order to solve the above problems, according to one aspect of the present invention, there is provided a drive device for an electric motor-driven four-wheel drive vehicle, comprising: a first clutch mechanism that switches the connection or disconnection of the power transmission system on the front-wheel side and the power transmission system on the rear-wheel side; a first electric motor that is connected to either the front-wheel side or the rear-wheel side more forward than the first clutch mechanism; a second electric motor that is connected to the other side of the front-wheel side or the rear-wheel side more forward than the first clutch mechanism; a second clutch mechanism that switches the connection or disconnection of the first electric motor and the drive shaft on the front-wheel side; a planetary gear mechanism that distributes the output of the first electric motor to the first clutch mechanism side and the second clutch mechanism side; and a third clutch mechanism that restricts the differential between the rotating element on the first clutch mechanism side of the planetary gear mechanism and the rotating element on the second clutch mechanism side.

[0013] In the drive device for the four-wheel drive vehicle, it may also be that the output shaft of the first electric motor is arranged in parallel with the drive shafts on the front-wheel side and the rear-wheel side.

[0014] In the drive device for the four-wheel drive vehicle, it may also be that the output shaft of the second electric motor is arranged in a direction orthogonal to the drive shafts on the front-wheel side and the rear-wheel side.

[0015] In the drive device for the four-wheel drive vehicle, it may also be that there is a drive shaft that connects the power transmission system on the front-wheel side and the power transmission system on the rear-wheel side, and an orthogonal gear is provided on the power transmission path between the rotating element on the first clutch mechanism side of the planetary gear mechanism and the drive shaft.

[0016] In the drive device for the four-wheel drive vehicle, it may also be that there is a control device that controls the drive device. In the first driving mode where the required torque is high, the control device connects the first clutch mechanism and the second clutch mechanism, disconnects the third clutch mechanism, controls the second electric motor so that the rotating element on the first clutch mechanism side of the planetary gear mechanism does not rotate, and controls the output of the first electric motor according to the required torque.

[0017] In the drive device for the four-wheel drive vehicle, it may also be that in the second driving mode where the required torque is low, the control device connects the second clutch mechanism and the third clutch mechanism, controls the output of the first electric motor, and controls or stops the output of the second electric motor according to the required torque.

[0018] In the drive device for the four-wheel drive vehicle, it may also be that during the transition from the first driving mode to the second driving mode, the control device connects the first clutch mechanism and the second clutch mechanism, gradually changes the coupling force of the third clutch mechanism, and at the same time gradually changes the outputs of the first electric motor and the second electric motor for replacement.

[0019] In the drive device of the four-wheel drive vehicle, it is also possible that a differential mechanism is provided on the drive shaft on the front wheel side, and a fourth clutch mechanism for adjusting power transmission to the drive shaft of the right rear wheel and a fifth clutch mechanism for adjusting power transmission to the drive shaft of the left rear wheel are provided on the drive shaft on the rear wheel side.

[0020] In the drive device of the four-wheel drive vehicle, it is also possible that the first electric motor is connected more on the front wheel side than the first clutch mechanism, and the second electric motor is connected more on the rear wheel side than the first clutch mechanism.

[0021] Advantageous Effects of the Invention

[0022] As described above, according to the present invention, it is possible to provide a drive device for an electric motor type four-wheel drive vehicle that can maximize the output of the electric motor and can drive the electric motor with high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram showing a structural example of a drive device for a four-wheel drive vehicle according to an embodiment of the present invention.

[0024] Figure 2 It is an explanatory diagram showing the characteristics of the first motor and the second motor.

[0025] Figure 3 It is an explanatory diagram showing an operation example of the drive device of the same embodiment for each vehicle load state.

[0026] Figure 4 It is an explanatory diagram showing an operation example of the drive device in a high load region.

[0027] Figure 5 It is an explanatory diagram showing an operation example of the drive device in a low load region.

[0028] Figure 6 It is an explanatory diagram showing an operation example of the drive device in an intermediate region.

[0029] Figure 7 It is an explanatory diagram showing an operation example of the drive device of the same embodiment for each drive mode.

[0030] Figure 8 It is an explanatory diagram showing an operation example of the drive device in the rear-wheel drive mode.

[0031] Figure 9 It is an explanatory diagram showing another operation example of the drive device in the rear-wheel drive mode.

[0032] REFERENCE SIGNS

[0033] 1: Drive device

[0034] 10: First differential mechanism

[0035] 21: First motor

[0036] 23: Second motor

[0037] 35: Second clutch mechanism

[0038] 37: Third clutch mechanism

[0039] 41: First clutch mechanism

[0040] 45: Fourth clutch mechanism

[0041] 47: Fifth clutch mechanism

[0042] 50: Control device Detailed implementation mode

[0043] Hereinafter, with reference to the drawings, a preferred implementation mode of the present invention will be described in detail.

[0044] In addition, in this specification and the drawings, components having substantially the same functional structure are denoted by the same reference numerals, and redundant descriptions are omitted.

[0045] <1. Overall structure of the drive device>

[0046] Refer to Figure 1 , and the overall structure of the drive device of a four-wheel drive vehicle according to an embodiment of the present invention will be described. Figure 1 is a schematic diagram showing the overall structure of the drive device 1 of this embodiment. Figure 1 The drive device 1 shown is a drive device of an electric vehicle with all-wheel drive (AWD: All-Wheel Drive) that drives the front wheels 3LF, 3RF and the rear wheels 3LR, 3RR by electric motors.

[0047] The drive device 1 includes a first motor 21, a second motor 23, a first differential mechanism 10, a second differential mechanism 31, a first clutch mechanism 41, a second clutch mechanism 35, a third clutch mechanism 37, a fourth clutch mechanism 45, a fifth clutch mechanism 47, and a control device 50. The drive shafts 5LF of the left front wheel 3LF and the drive shaft 5RF of the right front wheel 3RF are connected via the second differential mechanism 31. The drive shafts 5LR of the left rear wheel 3LR and the drive shafts 5RR of the right rear wheel 3RR are connected via the fourth clutch mechanism 45 and the fifth clutch mechanism 47.

[0048] The first differential mechanism 10 includes a planetary gear mechanism, which has a sun gear 15, pinions 12, a ring gear 13, and a carrier 11 that supports the pinions 12. The output shaft 21a of the first motor 21 is connected to the sun gear 15, and the output torque of the first motor 21 is transmitted to the first differential mechanism 10 via the sun gear 15. The first differential mechanism 10 distributes the output torque of the first motor 21 to the first clutch mechanism 41 side on the rear wheel side and the second clutch mechanism 35 side on the front wheel side. Specifically, a part of the output torque of the first motor 21 is transmitted to the second differential mechanism 31 via the pinions 12, the ring gear 13, the second clutch mechanism 35, and the gear mechanism 33. In addition, a part of the output torque of the first motor 21 is transmitted to the drive shaft 25 via the pinions 12, the carrier 11, and the bevel gear 39. The first differential mechanism 10 is configured to be able to generate differential rotation on the front wheel side and the rear wheel side.

[0049] The second differential mechanism 31 is composed of known differential gears and has two side gears respectively connected to the drive shafts 5LF of the left front wheel 3LF and 5RF of the right front wheel 3RF, and two pinions respectively meshing with the two side gears. The second differential mechanism 31 can, for example, cause the left front wheel 3LF and the right front wheel 3RF to generate differential rotation during turning or when driving on a rough road.

[0050] The first clutch mechanism 41 is provided between the bevel gear 39 connected to the first differential mechanism 10 and the drive shaft 25, and is switched between engaged and disengaged by the control device 50. The first clutch mechanism 41 has a function of switching the connection or disconnection between the power transmission system on the front wheel side and the power transmission system on the rear wheel side. The first motor 21 is connected more on the front wheel side than the first clutch mechanism 41, and the second motor 23 is connected more on the rear wheel side than the first clutch mechanism 41. The structure of the first clutch mechanism 41 may be any mechanism that can switch the power transmission on or off, and there is no particular limitation. The second clutch mechanism 35 may also be a known clutch mechanism such as a claw clutch or a disconnection mechanism exemplified in Japanese Unexamined Patent Application Publication No. 2018-17354, for example.

[0051] The second clutch mechanism 35 is provided in the power transmission path from the first differential mechanism 10 to the front wheel side and is switched between engagement and disengagement by the control device 50. The second clutch mechanism 35 has a function of switching whether the outputs of the first motor 21 and the second motor 23 are transmitted to the front wheel side, and also has a function of separating the front wheel side and the rear wheel side. For example, when the vehicle travels by front-wheel drive and four-wheel drive, the second clutch mechanism 35 is engaged, and when the vehicle travels by rear-wheel drive, the second clutch mechanism 35 is disengaged. The structure of the second clutch mechanism 35 is not particularly limited as long as it is a mechanism capable of switching the power transmission. The second clutch mechanism 35 can be, for example, a known clutch mechanism such as a claw clutch or a disconnection mechanism exemplified in Japanese Unexamined Patent Application Publication No. 2018-17354.

[0052] The third clutch mechanism 37 has a function of restricting the differential between the rotating elements on the first clutch mechanism 41 side and the second clutch mechanism 35 side of the first differential mechanism 10. In the present embodiment, the third clutch mechanism 37 is provided between the bracket 11 and the ring gear 13 and is configured to be able to adjust the engagement force by the control device 50. In a state where the third clutch mechanism 37 is fully engaged, the differential of the first differential mechanism 10 is restricted and the bracket 11 and the ring gear 13 are directly connected, and the same rotation (torque) can be transmitted to the front wheel side and the rear wheel side. In addition, by adjusting the engagement force of the third clutch mechanism 37, the power transmission efficiency between the bracket 11 side and the ring gear 13 side is variable. The structure of the third clutch mechanism 37 is not particularly limited as long as it is a mechanism for adjusting the engagement force.

[0053] The fourth clutch mechanism 45 and the fifth clutch mechanism 47 are connected to the drive shaft 25 via the orthogonal gear 43 and the clutch housing 49. The fourth clutch mechanism 45 is provided between the drive shaft 5LR of the left rear wheel 3LR and the clutch housing 49 and is configured to be able to adjust the engagement force by the control device 50. In addition, the fifth clutch mechanism 47 is provided between the drive shaft 5RR of the right rear wheel 3RR and the clutch housing 49 and is configured to be able to adjust the engagement force by the control device 50.

[0054] The drive shafts 5LF of the left front wheel 3LF and 5RF of the right front wheel 3RF are connected via a second differential mechanism 31 and configured to be able to distribute driving force. In contrast, the drive shafts 5LR of the left rear wheel 3LR and 5RR of the right rear wheel 3RR are respectively connected to a clutch housing 49 via a fourth clutch mechanism 45 or a fifth clutch mechanism 47 and configured to be independent of each other and able to adjust the power transmission efficiency. The structures of the fourth clutch mechanism 45 and the fifth clutch mechanism 47 are not particularly limited as long as they are mechanisms for adjusting the coupling force. The drive shafts 5LR of the left rear wheel 3LR and 5RR of the right rear wheel 3RR may also be connected via a differential mechanism instead of using the fourth clutch mechanism 45 and the fifth clutch mechanism 47. However, by using the fourth clutch mechanism 45 and the fifth clutch mechanism 47, the differential rotation of the left rear wheel 3LR and the right rear wheel 3RR can be adjusted more precisely, and the turning performance can be improved.

[0055] The first motor 21 and the second motor 23 are, for example, well-known synchronous motors and are controlled by controlling an inverter (not shown) by a control device 50. The first motor 21 is connected to be on either the front wheel side or the rear wheel side further forward than the first clutch mechanism 41. In the present embodiment, the first motor 21 is connected to be on the front wheel side further forward than the first clutch mechanism 41. The output shaft 21a of the first motor 21 is connected to the first differential mechanism 10. The output shaft 21a of the first motor 21 is arranged to be substantially parallel to the drive shafts 5LF and 5LR of the front wheels, and the output torque output from the first motor 21 can be efficiently transmitted to the second differential mechanism 31 provided on the drive shafts 5LF and 5RF of the front wheels without passing through an orthogonal gear.

[0056] Specifically, the output torque output from the first motor 21 can be transmitted to the left front wheel 3LF and the right front wheel 3RF via the first differential mechanism 10, the second clutch mechanism 35, the gear mechanism 33, the second differential mechanism 31, and the drive shafts 5LF and 5RF. In addition, the output torque output from the first motor 21 can be transmitted to the left rear wheel 3LR and the right rear wheel 3RR via the first differential mechanism 10, the orthogonal gear 39, the first clutch mechanism 41, the drive shaft 25, the orthogonal gear 43, the clutch housing 49, the fourth clutch mechanism 45 or the fifth clutch mechanism 47, and the drive shafts 5LR and 5RR.

[0057] The second motor 23 is connected to be on the other side of the front wheel side or the rear wheel side further forward than the first clutch mechanism 41. In the present embodiment, the second motor 23 is connected to be on the rear wheel side further forward than the first clutch mechanism 41. The output shaft 23a of the second motor 23 is connected to a drive shaft 25 that transmits driving force (rotation) between the front wheel side and the rear wheel side. In Figure 1 the example shown, the output shaft 23a of the second motor 23 functions as the drive shaft 25, but the output shaft 23a of the second motor 23 and the drive shaft 25 may also be connected via a gear mechanism.

[0058] The output torque output from the second motor 23 can be transmitted to the left front wheel 3LF and the right front wheel 3RF via the first clutch mechanism 41, the orthogonal gear 39, the third clutch mechanism 37, the second clutch mechanism 35, the gear mechanism 33, the second differential mechanism 31, and the drive shafts 5LF, 5RF. Further, the output torque output from the second motor 23 can be transmitted to the left rear wheel 3LR and the right rear wheel 3RR via the orthogonal gear 43, the clutch housing 49, the fourth clutch mechanism 45 or the fifth clutch mechanism 47, and the drive shafts 5LR, 5RR.

[0059] Figure 2 It is an explanatory diagram showing the characteristics of the first motor 21 and the second motor 23. The maximum rated torque of the first motor 21 is greater than the maximum rated torque of the second motor 23. The rotation region in which the first motor 21 can output the maximum rated torque becomes a region lower than the rotation region in which the second motor 23 can output the maximum rated torque. That is, the first motor 21 is configured to be able to efficiently output the maximum rated torque in a rotation region lower than that of the second motor 23, and the second motor 23 is configured to be able to efficiently output the maximum rated torque in a rotation region higher than that of the first motor 21 (in Figure 2 it is shown as the "efficiency point").

[0060] The control device 50 is constituted by, for example, a processor or a circuit such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit), and a storage element such as a RAM (Random Access Memory) or a ROM (Read Only Memory). Part or all of the control device 50 may be constituted by an updatable element such as firmware, or may be a program module that executes instructions from a CPU or the like.

[0061] In the drive device 1 of the present embodiment, the first motor 21 and the second motor 23 are mechanically connected to the front, rear, left, and right drive wheels 3LF, 3RF, 3LR, 3RR. Therefore, the outputs of the first motor 21 and the second motor 23 can be transmitted to the front wheel side and the rear wheel side, respectively. Therefore, when driving either the front wheel side or the rear wheel side, the total output of the first motor 21 and the second motor 23 can be used to the maximum extent. Further, the drive device 1 of the present embodiment connects the power transmission system on the front wheel side and the power transmission system on the rear wheel side by engaging the first clutch mechanism 41. Therefore, since the rotation (torque) of the front wheel side and the rear wheel side is synchronized mechanically, the responsiveness can be improved.

[0062] In addition, the drive device 1 of the present embodiment is mechanically connected to the front, rear, left, and right drive wheels 3LF, 3RF, 3LR, and 3RR together with the first motor 21 and the second motor 23. Therefore, the first motor 21 and the second motor 23 can be driven efficiently near the efficiency point respectively. Accordingly, the first motor 21 and the second motor 23 can be used separately according to the required driving force of the vehicle, and at the same time, the driving of the vehicle can be efficiently controlled.

[0063] Moreover, the drive device 1 of the present embodiment can separate the front wheel side and the rear wheel side through the first clutch mechanism 41, the second clutch mechanism 35, the fourth clutch mechanism 45, or the fifth clutch mechanism 47. Therefore, the vehicle can travel while switching between front-wheel drive, rear-wheel drive, or four-wheel drive.

[0064] <2. Operation example>

[0065] Next, an operation example of the drive device 1 of the present embodiment will be described.

[0066] (2.1. Separate use of motors)

[0067] First, with reference to Figures 3 to 6 , an example of the separate use of the first motor 21 and the second motor 23 will be described. Figure 3 is an explanatory diagram showing the connection states of the first clutch mechanism 41, the second clutch mechanism 35, the third clutch mechanism 37, the fourth clutch mechanism 45, and the fifth clutch mechanism 47 and the driving states of the first motor 21 and the second motor 23 for each vehicle load state.

[0068] At the start of the vehicle (at the start of travel), or in a high-load region such as when a large acceleration is requested, a relatively large driving force is requested from the vehicle. In this case, the control mode is set to the first driving mode. In the first driving mode, the control device 50 sets the first clutch mechanism 41, the second clutch mechanism 35, the fourth clutch mechanism 45, and the fifth clutch mechanism 47 to the engaged state, and on the other hand, sets the third clutch mechanism 37 to the open state, and drives the first motor 21 and the second motor 23 together. Thus, as Figure 4 shown, the outputs of the first motor 21 and the second motor 23 can be respectively transmitted to the front, rear, left, and right drive wheels 3LF, 3RF, 3LR, and 3RR, and the outputs of the first motor 21 and the second motor 23 are used together to make the vehicle travel. In addition, since the third clutch mechanism 37 is in the open state, differential rotation between the front wheel side and the rear wheel side caused by the first differential mechanism 10 is allowed, and driving performance such as turning performance can be improved.

[0069] In the first driving mode, the control device 50 drives either or both of the first motor 21 and the second motor 23 near the efficiency point. Thus, as the vehicle as a whole, high-efficiency operation can be achieved. In addition, in the present embodiment, the driving forces transmitted to the left rear wheel 3LR and the right rear wheel 3RR can be independently adjusted by the fourth clutch mechanism 45 and the fifth clutch mechanism 47. Therefore, the control device 50 can improve the turning performance by respectively adjusting the coupling forces of the fourth clutch mechanism 45 and the fifth clutch mechanism 47 based on the vehicle speed, acceleration, steering angle, etc. Further, in the first driving mode, when it is desired to set the front-rear differential rotation to zero, the third clutch mechanism 37 may be coupled.

[0070] On the other hand, during constant-speed driving or in a low-load region such as when a small acceleration is requested, a relatively small driving force is requested for the vehicle. In this case, the control mode is set to the second driving mode. In the second driving mode, the control device 50 sets the second clutch mechanism 35 and the third clutch mechanism 37 to the coupled state and releases the first clutch mechanism 41, the fourth clutch mechanism 45, and the fifth clutch mechanism 47. In this state, the control device 50 stops the second motor 23 and controls the output of the first motor 21 according to the requested driving force. Thus, as Figure 5 shown, the vehicle can be driven only by the first motor 21, and the first motor 21 can efficiently transmit the driving force to the front wheel side without passing through the bevel gear. Even when the vehicle decelerates, by setting the control device 50 to the second driving mode and performing regenerative control, efficient power generation can be achieved.

[0071] In the intermediate region between the high-load region and the low-load region, the control mode is set to the intermediate mode. In the intermediate mode, the control device 50 sets the first clutch mechanism 41 and the second clutch mechanism 35 to the coupled state. On the other hand, the third clutch mechanism 37, the fourth clutch mechanism 45, and the fifth clutch mechanism 47 are set to the released state. In addition, as Figure 6 shown, the control device 50 controls the driving state or the regenerative state of the second motor 23 that transmits power via the bevel gear 39 while maintaining the state where the first motor 21 that can efficiently transmit power to the front wheel side without passing through the bevel gear is driven, and performs shift operation. Thus, as the vehicle as a whole, high-efficiency operation can be achieved, and smooth transition between the high-load region and the low-load region can be achieved.

[0072] Alternatively, in the intermediate region, the control device 50 may also set the second clutch mechanism 35 to the engaged state, and gradually change the engagement forces of the first clutch mechanism 41 and the third clutch mechanism 37, as well as the outputs of the first motor 21 and the second motor 23, to perform variable-speed operation. In this case, the closer the control device 50 is to the low-load region, the lower the engagement force of the first clutch mechanism 41, the higher the engagement force of the third clutch mechanism 37, and while adjusting the output of the first motor 21, the output of the second motor 23 is gradually reduced. Thereby, as a whole vehicle, high-efficiency operation can be achieved, and smooth transition between the high-load region and the low-load region can be realized.

[0073] (2.2. Switching of driving modes)

[0074] Next, with reference to Figures 7 to 9 , an example of the switching of driving modes will be described. Figure 7 It is an explanatory diagram showing the engaged states of the first clutch mechanism 41, the second clutch mechanism 35, the third clutch mechanism 37, the fourth clutch mechanism 45, and the fifth clutch mechanism 47, and the driving states of the first motor 21 and the second motor 23 for each driving mode.

[0075] When the vehicle is in front-wheel drive, the control device 50 sets the first clutch mechanism 41, the fourth clutch mechanism 45, and the fifth clutch mechanism 47 to the open state, and sets the second clutch mechanism 35 and the third clutch mechanism 37 to the engaged state. In this state, the control device 50 controls the output of the first motor 21 according to the requested driving force. Thereby, the output of the first motor 21, which can efficiently transmit the driving force to the front-wheel side without passing through the bevel gear, can be transmitted to the front-wheel side to make the vehicle travel (in the same state as Figure 5 ). When performing front-wheel drive, when the vehicle decelerates, the control device 50 performs regeneration control on the first motor 21, and efficient power generation can be achieved.

[0076] Alternatively, when the vehicle is in front-wheel drive, the control device 50 may also set the third clutch mechanism 37, the fourth clutch mechanism 45, and the fifth clutch mechanism 47 to the open state, and set the first clutch mechanism 41 and the second clutch mechanism 35 to the engaged state. In this state, the control device 50 controls the outputs of the first motor 21 and the second motor 23. Thereby, the outputs of the first motor 21 and the second motor 23 can be transmitted to the front-wheel side to make the vehicle travel (the power transmission state is the same as Figure 6 ).

[0077] In the case of rear-wheel drive of the vehicle, the control device 50 sets the first clutch mechanism 41, the second clutch mechanism 35, and the third clutch mechanism 37 to the open state. In this state, the control device 50 controls the output of the second motor 23 and variably controls the engaging force of the fourth clutch mechanism 45 and the fifth clutch mechanism 47 according to the turning state. Thus, as Figure 8 shown, the output of the second motor 23 can be transmitted to the rear-wheel side to make the vehicle travel. When performing rear-wheel drive, when the vehicle decelerates, the control device 50 performs regenerative control on the second motor 23 to generate electricity.

[0078] Alternatively, in the case of rear-wheel drive of the vehicle, the control device 50 may set the second clutch mechanism 35 to the open state and set the first clutch mechanism 41 and the third clutch mechanism 37 to the engaged state. In this state, the control device 50 controls the output of either the first motor 21 or the second motor 23 and variably controls the engaging force of the fourth clutch mechanism 45 and the fifth clutch mechanism 47 according to the turning state. Thus, as Figure 9 shown, the outputs of the two motors, i.e., the first motor 21 and the second motor 23, can be transmitted to the rear-wheel side to make the vehicle travel. Additionally, when performing Figure 9 the rear-wheel drive shown, when the vehicle decelerates, the control device 50 can generate electricity by performing regenerative control on either the first motor 21 or the second motor 23. In addition, the third clutch mechanism 37 may be engaged.

[0079] In the case of four-wheel drive of the vehicle, the control device 50 sets the first clutch mechanism 41 and the second clutch mechanism 35 to the engaged state and sets the third clutch mechanism 37 to the open state or the engaged state. In this state, the control device 50 controls the output of either the first motor 21 or the second motor 23 and variably controls the engaging force of the fourth clutch mechanism 45 and the fifth clutch mechanism 47 according to the turning state. When performing four-wheel drive, the above-described separate use control of the motors can be performed (refer to Figure 3 ).

[0080] Thus, in the drive device 1 of the present embodiment, an electric motor type four-wheel drive vehicle can be realized, and the electric motor type four-wheel drive vehicle can separately use front-wheel drive with excellent vehicle maneuverability, rear-wheel drive with excellent driving performance, and four-wheel drive with excellent turning performance and stability.

[0081] (2.3. Turning Performance)

[0082] As described above, the drive device 1 of the present embodiment includes a fourth clutch mechanism 45 capable of adjusting the driving force transmitted to the left rear wheel 3LR and a fifth clutch mechanism 47 capable of adjusting the driving force transmitted to the right rear wheel 3RR. Therefore, the turning performance can be improved by adjusting (left and right vectoring) the coupling force of the fourth clutch mechanism 45 and the fifth clutch mechanism 47. In addition, by setting the first clutch mechanism 41 in an open state to separate the front wheel side and the rear wheel side, driving the rear wheel side by the second motor 23, and driving the front wheel side with an output smaller than that of the first motor 21 or performing regenerative driving on the front wheel side, the driving force of the front and rear wheels can be adjusted separately from or together with the left and right vectoring. Therefore, the controllability of the yaw rotation of the vehicle is improved, and the turning performance can be improved.

[0083] As described above, the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to this example. Obviously, those skilled in the art with ordinary knowledge in the technical field to which the present invention pertains can conceive of various modification examples or correction examples within the scope of the technical idea described in the claims, and it should be understood that these belong to the technical scope of the present invention.

[0084] In addition, in the above embodiment, the first electric motor is arranged on the front wheel side of the first clutch mechanism, and the second electric motor is arranged on the rear wheel side of the first clutch mechanism, but the present invention is not limited to this. That is, the first electric motor may be arranged on the rear wheel side of the first clutch mechanism, and the second electric motor may be arranged on the front wheel side of the first clutch mechanism.

Claims

1. A drive device for an electric motor - type four - wheel drive vehicle, comprising: A first clutch mechanism that switches the connection or disconnection between the power transmission system on the front - wheel side and the power transmission system on the rear - wheel side; A first electric motor connected to either the front - wheel side or the rear - wheel side, which is more forward than the first clutch mechanism; A second electric motor connected to the other side of either the front - wheel side or the rear - wheel side, which is more forward than the first clutch mechanism; A second clutch mechanism that switches the connection or disconnection between the first electric motor and the drive shaft on either the front - wheel side or the rear - wheel side; A planetary gear mechanism that distributes the output of the first electric motor to the first clutch mechanism side and the second clutch mechanism side; A third clutch mechanism that restricts the differential rotation between the rotating element on the first clutch mechanism side and the rotating element on the second clutch mechanism side of the planetary gear mechanism; And A control device that controls the drive device. In a first driving mode with a high requested torque, the control device connects the first clutch mechanism and the second clutch mechanism, disconnects the third clutch mechanism, and controls the outputs of the first electric motor and the second electric motor.

2. The drive device for an electric motor - type four - wheel drive vehicle according to claim 1, wherein The output shaft of the first electric motor is arranged parallel to the drive shafts on the front - wheel side and the rear - wheel side.

3. The drive device for an electric motor - type four - wheel drive vehicle according to claim 1, wherein The output shaft of the second electric motor is arranged in a direction orthogonal to the drive shafts on the front - wheel side and the rear - wheel side.

4. The drive device for an electric motor - type four - wheel drive vehicle according to claim 2, wherein The output shaft of the second electric motor is arranged in a direction orthogonal to the drive shafts on the front - wheel side and the rear - wheel side.

5. The drive device for an electric motor - type four - wheel drive vehicle according to any one of claims 1 to 4, wherein There is a drive shaft that connects the power transmission system on the front - wheel side and the power transmission system on the rear - wheel side, and an orthogonal gear is provided on the power transmission path between the drive shaft and the rotating element on the first clutch mechanism side of the planetary gear mechanism.

6. The drive device for an electric motor - type four - wheel drive vehicle according to any one of claims 1 to 4, wherein In a second driving mode with a low requested torque, the control device connects the second clutch mechanism and the third clutch mechanism, controls the output of the first electric motor, and controls or stops the output of the second electric motor according to the requested torque.

7. The drive device for an electric motor - type four - wheel drive vehicle according to claim 6, wherein During the transition from the first driving mode to the second driving mode, the control device connects the first clutch mechanism and the second clutch mechanism, gradually changes the coupling force of the third clutch mechanism, and at the same time gradually changes the outputs of the first electric motor and the second electric motor for replacement.

8. The drive device for an electric motor - type four - wheel drive vehicle according to any one of claims 1 to 4, wherein The front wheel drive shaft is equipped with a differential mechanism. The drive shaft on the rear wheel side is provided with a fourth clutch mechanism for regulating power transmission to the drive shaft of the right rear wheel and a fifth clutch mechanism for regulating power transmission to the drive shaft of the left rear wheel.

9. The driving device for an electric motor-type four-wheel drive vehicle according to any one of claims 1 to 4, wherein: The first electric motor is connected to the front wheel side of the first clutch mechanism, and the second electric motor is connected to the rear wheel side of the first clutch mechanism.

Images