JP2008038966A - Traveling device - Google Patents

Abstract

When a driving force is varied between different driving wheels, the device is made compact and the mounting property to a vehicle is improved.
A traveling device includes a planetary gear device, an electric motor, and a clutch. The planetary gear device 11 includes a ring gear 11R, a carrier 11C, and a sun gear 11S. The electric motor 12 drives the left rear wheel 3l and is connected to the ring gear 11R. Also, the clutch 13 changes the torque of both driving wheels between the left rear wheel 3l and the right rear wheel 3r driven by transmission of power from the carrier 11C by changing its fastening force.
[Selection] Figure 1

Description

  The present invention relates to a traveling device capable of changing each driving force between a plurality of driving wheels.

  In recent years, in order to improve vehicle running performance, drivability, safety, and the like, a driving force difference is generated between a plurality of driving wheels, for example, left and right wheels. For example, Patent Document 1 discloses a first electric motor whose output shaft is connected to a first rotating element of a differential device, and a second electric motor whose output shaft is connected to a second rotating element of a differential device. A travel assist device is disclosed in which one of the left and right wheels is connected to the output shaft of the first electric motor and the other is connected to the second electric motor.

JP-A-11-170881

  However, since the travel assist device disclosed in Patent Document 1 includes two electric motors, the overall size and mass of the device increase. As a result, the mountability on the vehicle may be deteriorated. Accordingly, the present invention has been made in view of the above, and provides a traveling device that can be compactly mounted and improved in mounting on a vehicle when providing a driving force difference between a plurality of driving wheels. The purpose is to do.

In order to achieve the above object, a traveling device according to the present invention is mounted on a vehicle and changes a driving force between different driving wheels, and includes a first rotating element, a second rotating element, and a third rotating element. A power split mechanism including a rotating element; and a power generating means connected to the first rotating element;
A first driving wheel driven by power transmitted from the power generating means; a second driving wheel driven by the power of the power generating means transmitted via the second rotating element; By applying braking to the rotation of the third rotating element, torque transmitted from the power generating means to the first driving wheel and transmitted to the second driving wheel via the second rotating element. And a driving force adjusting means for changing the torque.

  This traveling device can change each driving force between different driving wheels by a single power generation means. Thereby, when providing the driving force difference to the plurality of driving wheels, the apparatus can be made compact and the mounting property to the vehicle can be improved.

  In the traveling device according to the next aspect of the present invention, in the traveling device, the power split mechanism is a planetary gear device having a sun gear, a carrier, and a ring gear as rotating elements, and the first rotating element is the ring gear or the sun gear. The second rotating element is a carrier, and the third rotating element is different from the first rotating element among the sun gear and the ring gear.

  In the traveling apparatus according to the next aspect of the present invention, in the traveling apparatus, the driving force adjusting means brakes the rotation of the third rotating element, whereby the driving force of the first driving wheel and the second driving force are applied. The rotation direction of the third rotation element in a region where the driving force of the wheel can be changed is negative, and the first driving wheel and the second driving wheel required from the target yaw moment targeted by the vehicle When the target rotation speed of the third rotation element set based on the driving force distribution ratio is greater than a predetermined threshold value, the calculation is based on the difference between the target rotation speed and the predetermined threshold value. The third rotation set based on a driving force distribution ratio between the first driving wheel and the second driving wheel required from the target yaw moment using the corrected torque of the third rotating element. While correcting the target torque of the element And changes the torque the power generating means is generated based on the correction torque.

  The travel device according to the next aspect of the present invention is characterized in that, in the travel device, the one that cannot reduce the driving force between the first drive wheel and the second drive wheel is braked by a braking means. .

  In the travel device according to the next aspect of the present invention, in the travel device, the power generation means is an electric motor, and the first drive wheel and the second drive for braking the first drive wheel during braking of the vehicle. After braking using the second braking device that brakes the wheel, after the braking of the third rotating element by the driving force adjusting means is released, the electric power is regenerated in the electric motor, and the electric energy generated by the electric motor is Based on this, the braking force of the first braking device is adjusted.

  In the travel device according to the next aspect of the present invention, in the travel device, the power generation means is an electric motor, and the first drive wheel and the second drive for braking the first drive wheel during braking of the vehicle. After braking using a second braking device that brakes the wheel, the driving force adjusting means brakes the third rotating element to regenerate power in the motor, and based on the amount of power generated by the motor, The braking force of the first braking device and the braking force of the second braking device are adjusted.

  In the traveling device according to the present invention, when the driving force difference is provided to the plurality of driving wheels, the device can be made compact and the mounting property to the vehicle can be improved.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited by the best mode for carrying out the invention (hereinafter referred to as an embodiment). In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

  In the following description, the case where the driving force of each wheel is changed between the driving wheels on the left and right sides of the vehicle will be described, but the present invention can be applied to the case where the driving force is changed between the driving wheels before and after the vehicle. The present invention can also be applied to a case where the driving force is changed between driving wheels in the front, rear, left and right directions. That is, the present invention can be applied when changing the driving force between a plurality of driving wheels. Moreover, in the following description, the case where the present invention is applied to a passenger car, a truck, a bus, and other vehicles is taken as an example, but the application target of the present invention is not limited to such a vehicle.

  In this embodiment, a power split mechanism (for example, a planetary gear device) including a first rotating element, a second rotating element, and a third rotating element, and a first drive wheel are driven and connected to the first rotating element. The torque of both driving wheels is changed between the first driving wheel and the second driving wheel to which power is transmitted from the second rotating element by applying braking to the rotation of the third rotating element. And a driving force adjusting means. In the following description, the number of revolutions refers to the number of revolutions per unit time, and rpm (revolution per minute: revolutions per minute) is used. Next, the traveling device according to this embodiment will be described.

  FIG. 1 is an explanatory diagram illustrating a traveling device according to this embodiment and a vehicle including the traveling device according to this embodiment. The vehicle 1 includes a traveling device 10 according to this embodiment, and travels (forwards) in the direction of arrow X in FIG. In this embodiment, left and right are determined with respect to the direction in which the vehicle 1 moves forward (the direction of the arrow X in FIG. 1).

  The vehicle 1 includes a left front wheel 21, a right front wheel 2r, a left rear wheel 31, and a right rear wheel 3r. The left rear wheel 3l and the right rear wheel 3r are respectively driven by the traveling device 10 according to this embodiment, and the left front wheel 21 and the right front wheel 2r are respectively driven by the front wheel drive device 4. Thus, the vehicle 1 is a so-called four-wheel drive (4WD: 4 Wheel Drive) vehicle in which all wheels are drive wheels. The driving system of the vehicle 1 is not limited to this, and a driving system such as a so-called FR (Front engine Rear drive), a so-called FF (Front engine Front drive), or the like may be used.

  A traveling device 10 according to this embodiment includes a planetary gear device (power distribution mechanism) 11 configured by a planetary gear train, a clutch 13 that is a transmission power adjusting means, and a first drive shaft (hereinafter referred to as a first drive shaft). 16l and a second drive shaft (hereinafter referred to as second drive shaft) 16r. In this embodiment, the first drive shaft 161 is disposed on the left side with respect to the forward direction of the vehicle 1 (the direction of the arrow X in FIG. 1), and drives the left rear wheel (corresponding to the first drive wheel) 3l. To do. The second drive shaft 16r is disposed on the right side with respect to the forward direction of the vehicle 1 (the direction of the arrow X in FIG. 1), and drives the right rear wheel (corresponding to the second drive wheel) 3r.

  The vehicle 1 according to this embodiment changes the driving force between the left and right drive wheels (the left rear wheel 3l and the right rear wheel 3r in this embodiment) by mounting the traveling device 10. Can be made. Here, the control for changing the driving force of each driving wheel according to the traveling condition of the vehicle in the left and right driving wheels, the front and rear driving wheels, or the front and rear driving wheels is called driving force distribution control. In this embodiment, by changing the driving force of the left rear wheel 3l and the driving force of the right rear wheel 3r, the driving force of which is controlled by the traveling device 10, between the left rear wheel 3l and the right rear wheel 3r. Thus, driving force distribution control is executed.

  Power is input to the traveling device 10 from an electric motor 12 that is power generation means. The electric motor 12 is a so-called electric motor that converts electric energy into kinetic energy, but a hydraulic motor may be used. A first power transmission gear 14 is attached to a rotating shaft (motor rotating shaft) 12 s of the electric motor 12. The first power transmission gear 14 meshes with a first counter gear 14C attached to the first drive shaft 16l. And the motive power of the electric motor 12 adjusted with the planetary gear apparatus 11 with which the traveling apparatus 10 is equipped, and the clutch 13 is transmitted to the left rear wheel 3l via the 1st drive shaft 16l.

  The traveling device 10 is attached with a power transmission shaft 11Cs. A second power transmission gear 15 is attached to the power transmission shaft 11Cs. The second power transmission gear 15 meshes with a second counter gear 15C attached to the second drive shaft 16r. Then, the power of the electric motor 12 adjusted by the planetary gear device 11 and the clutch 13 included in the traveling device 10 is transmitted to the right rear wheel 3r via the second drive shaft 16r. The power may be transmitted between the motor rotating shaft 12s and the first drive shaft 16l and between the power transmission shaft 11Cs and the second drive shaft 16r by the chain and the sprocket.

  The electric motor 12 is controlled by an inverter 23. The inverter 23 is connected to an in-vehicle power source 9 such as a nickel-hydrogen battery or a lithium ion battery, and supplies electric power to the motor 12 as necessary. The inverter 23 is controlled using an operation control function of an ECU (Electronic Control Unit) 50. Further, when the driving force distribution control for changing the driving force between the left rear wheel 3l and the right rear wheel 3r is executed, the inverter 23 is controlled by the driving force distribution control device 30 according to this embodiment. The driving force distribution control device 30 according to this embodiment is provided in the ECU 50.

  A resolver 45 is attached to the motor rotation shaft 12s as first motor rotation speed detection means for detecting the rotation speed of the motor 12. The ECU 50 and the driving force distribution control device 30 acquire the rotation information of the electric motor 12 detected by the resolver 45 and control the electric motor 12. Further, the rotation speeds of the first drive shaft 161 and the second drive shaft 16r are detected by the first drive shaft rotation speed sensor 44l and the second drive shaft rotation speed sensor 44r, respectively, and the driving force distribution control according to this embodiment is performed. Used when executing.

  The planetary gear device 11 included in the traveling device 10 according to this embodiment is a so-called single pinion type planetary gear device, which includes a sun gear (first rotating element) 11S, a carrier (second rotating element) 11C, and a ring gear (first gear). 3 rotation elements) 11R as rotation elements. The planetary gear device applicable to the traveling device 10 according to this embodiment is not limited to the single pinion type. For example, a so-called double pinion type planetary gear may be used in consideration of the stress acting on each rotating element of the planetary gear device 11 from the magnitude of power input to the planetary gear device 11.

  The motor rotating shaft 12 s is connected to the ring gear 11 </ b> R of the planetary gear device 11. Further, the power transmission shaft 11Cs is connected to the carrier 11C of the planetary gear device 11. A clutch disk 13D of the clutch 13 is connected to the sun gear 11S of the planetary gear device 11. The stationary portion 13S of the clutch 13 is fixed to the casing B of the traveling device 10 and receives a reaction force from the clutch disk 13D.

In the travel device according to this embodiment, the shaft torque (first drive shaft torque) Tl of the first drive shaft 16l is expressed by equation (1), and the shaft torque (second drive shaft torque) Tr of the second drive shaft 16r is expressed by equation (1). It becomes like (2).
Tl = gdl × (Tm1−Tcl / ρ) (1)
Tr = gdr × (1 + 1 / ρ) × Tcl (2)
Here, gdl is a gear ratio between the first power transmission gear 14 and the first counter gear 14C, gdr is a gear ratio between the second power transmission gear 15 and the second counter gear 15C, and ρ is the number of teeth of the planetary gear unit 11. Ratio (the number of teeth of the sun gear 11S / the number of teeth of the ring gear 11R), Tm1 is the torque of the electric motor 12, and Tcl is the torque (clutch torque) generated by the clutch 13.

  Here, the clutch torque Tcl can be adjusted by changing the torque capacity of the clutch 13 by adjusting the fastening force Fc of the clutch 13 which is a driving force adjusting means. The clutch 13 is fastened by the hydraulic pressure generated by the clutch hydraulic pressure generator 20C. Between the clutch hydraulic pressure generator 20C and the clutch 13, a clutch actuator 21 for adjusting the hydraulic pressure supplied to the clutch 13 is provided as clutch control means. By controlling the clutch actuator 21 by the driving force distribution control device 30 provided in the ECU 50, the hydraulic pressure supplied to the clutch 13 can be changed and the fastening force Fc of the clutch 13 can be adjusted. The clutch 13 is not limited to a hydraulic type, and for example, an electromagnetic clutch may be used. Since the electromagnetic clutch has a quick response, the control response is improved, which is preferable.

  In the traveling device 10 according to this embodiment, the torque Tm1 of the electric motor 12 is changed, and the fastening force Fc of the clutch 13 that is a driving force adjusting means connected to the sun gear 11S of the planetary gear device 11 is adjusted. Then, the clutch torque Tcl is changed. As a result, the clutch 13 brakes the rotation of the sun gear 11S of the planetary gear unit 11, adjusts the reaction force generated in the sun gear 11S, and changes the power distributed to the ring gear 11R and the carrier 11C of the planetary gear unit 11. . As a result, the driving force transmitted to the first driving shaft 16l and the driving force transmitted to the second driving shaft 16r can be changed.

  For example, the turning performance of the vehicle 1 can be improved by increasing the driving force of the driving wheels outside the curve while the vehicle 1 is turning. Further, if the driving force of the driving wheels inside the curve is increased while the vehicle 1 is turning, oversteering of the vehicle 1 can be suppressed and the vehicle 1 can be prevented from falling into a spin.

  The traveling device 10 according to this embodiment includes a single-pinion type planetary gear device 11 as a power split mechanism. In this case, in the alignment chart of the single-pinion type planetary gear device, an outer rotating element (sun gear or ring gear) is provided. ) May be connected to the clutch 13 which is a driving force adjusting means. That is, as described above, the clutch disk 13D of the clutch 13 may be connected to the sun gear 11S of the planetary gear apparatus 11 and the clutch disk 13D of the clutch 13 may be connected to the ring gear 11R of the planetary gear apparatus 11. When the clutch disk 13D of the clutch 13 is connected to the ring gear 11R, the motor rotating shaft 12s is preferably connected to the sun gear 11S. In this way, the ratio of the driving force transmitted to the first drive shaft 16l and the driving force transmitted to the second drive shaft 16r can be changed by adjusting the clutch engagement force Fc. it can.

  Even when the traveling device 10 according to this embodiment includes a double pinion type planetary gear device as a power split mechanism, in the collinear diagram of the double pinion type planetary gear device, an outer rotating element (sun gear or carrier) ) May be connected to the clutch 13 which is a driving force adjusting means. That is, in the double pinion type planetary gear device, the clutch disk 13D of the clutch 13 is connected to the sun gear, and the clutch disk 13D of the clutch 13 is connected to the carrier of the planetary gear device. In this way, the ratio of the driving force transmitted to the first drive shaft 16l and the driving force transmitted to the second drive shaft 16r can be changed by adjusting the clutch engagement force Fc. it can.

  The first drive shaft 16l is provided with a first braking device 17l for braking the left rear wheel 3l, and the second drive shaft 16r is provided with a second braking device 17r for braking the right rear wheel 3r. The first braking device 17l and the second braking device 17r generate a braking force by the hydraulic pressure supplied from the braking device hydraulic pressure generator 20B. A first braking actuator 22l is provided as a first braking device control means between the first braking device 17l and the braking device hydraulic pressure generator 20B, and the second braking device 17r and the braking device hydraulic pressure generator 20B In the meantime, a second braking actuator 22r is provided as a second braking device control means. The first braking actuator 22l and the second braking actuator 22r are controlled by the ECU 50 or the driving force distribution control device 30, respectively. With such a configuration, the first braking device 17l and the second braking device 17r can independently adjust the braking force.

  The left front wheel 21 and the front wheel drive device 4 are connected by a left front wheel drive shaft 51, and the right front wheel 2r and the front wheel drive device 4 are connected by a right front wheel drive shaft 5r. The left front wheel 21 and the right front wheel 2r are drive wheels of the vehicle 1 and are steered wheels that are steered by the handle 6 to determine the traveling direction of the vehicle 1. The steering angles of the left front wheel 21 and the right front wheel 2r are detected by the steering angle sensor 42, taken into the driving force distribution control device 30, and used for driving force distribution control.

  The ECU 50 includes sensors such as an accelerator opening sensor 40 that detects the opening of the accelerator 7, a brake sensor 41 that detects the pedaling force of the brake 8, a vehicle speed sensor 43 that detects the speed (vehicle speed) of the vehicle 1, and a yaw sensor 46. Is connected. Information detected by these sensors is taken into the ECU 50 and the driving force distribution control device 30 and used for driving control of the vehicle 1 and driving force distribution control according to this embodiment. Next, the driving force distribution control device 30 that controls the operation of the traveling device 10 according to this embodiment will be described.

  FIG. 2 is a conceptual diagram showing the configuration of the driving force distribution control device according to this embodiment. As shown in FIG. 2, the driving force distribution control device 30 is configured to be incorporated in the ECU 50. The ECU 50 includes a CPU (Central Processing Unit) 50p, a storage unit 50m, an input port 55 and an output port 56, and an input interface 57 and an output interface 58.

  In addition, separately from ECU50, the driving force distribution control apparatus 30 which concerns on this embodiment may be prepared, and this may be connected to ECU50. When realizing the start control of the internal combustion engine according to this embodiment, the driving force distribution control device 30 can use the control function for the electric motor 12 provided in the ECU 50 when the vehicle 1 is driven. May be.

The driving force distribution control device 30 includes an operation condition determination unit 31, a control parameter calculation unit 32, and a driving force control unit 33. These are the parts that execute the starting control of the internal combustion engine according to this embodiment. In this embodiment, the driving force distribution control device 30 is configured as a part of the CPU 50 p that constitutes the ECU 50. And CPU 50p, the storage unit 50m, are connected by a bus 54 _3. Further, the operating condition determination unit 31, the control parameter calculation unit 32, and the driving force control unit 33 included in the CPU 50p are connected via buses 54 ₁ and 54 ₂ , an input port 55, and an output port 56.

  As a result, the driving condition determination unit 31, the control parameter calculation unit 32, and the driving force control unit 33 constituting the driving force distribution control device 30 can exchange control data with each other and issue commands to one side. Composed. Further, the driving force distribution control device 30 can acquire control data of the electric motor 12 and the first braking device 17l of the ECU 50 and use them. Further, the driving force distribution control device 30 can interrupt the driving force distribution control according to this embodiment into an operation control routine provided in advance in the ECU 50.

  An input interface 57 is connected to the input port 55. The input interface 57 includes an accelerator opening sensor 40, a brake sensor 41, a steering angle sensor 42, a vehicle speed sensor 43, a first drive shaft rotational speed sensor 44l, a second drive shaft rotational speed sensor 44r, a resolver 45, a yaw sensor 46, and others. Sensors that acquire information necessary for controlling the traveling device 10 are connected. Signals output from these sensors are converted into signals that can be used by the CPU 50 p by the A / D converter 57 a and the digital input buffer 57 d in the input interface 57 and sent to the input port 55. Thereby, CPU50p can acquire information required for control of electric motor 12, and driving force distribution control concerning this embodiment.

  An output interface 58 is connected to the output port 56. The output interface 58 includes an inverter 23 for controlling the electric motor 12, a clutch actuator 21 for controlling the fastening force Fc of the clutch 13, a first braking actuator 22l for controlling the braking force of the first braking device 17l, and a second braking. The second braking actuator 22r for controlling the braking force of the device 17r and other control targets in the driving force distribution control are connected.

The output interface 58 includes control circuits 58 ₁ , 58 _{2 and the} like, and operates the control target based on a control signal calculated by the CPU 50p. With such a configuration, based on output signals from the sensors, the CPU 50p of the ECU 50 can control the driving force of the left rear wheel 3l and the driving force of the right rear wheel 3r.

  The storage unit 50m stores a computer program including a processing procedure for driving force distribution control according to this embodiment, a control map, or a control data map used for driving force distribution control according to this embodiment. Here, the storage unit 50m can be configured by a volatile memory such as a RAM (Random Access Memory), a nonvolatile memory such as a flash memory, or a combination thereof.

  The computer program may be capable of realizing the processing procedure of the driving force distribution control according to this embodiment in combination with the computer program already recorded in the CPU 50p. The driving force distribution control device 30 implements the functions of the operating condition determination unit 31, the control parameter calculation unit 32, and the driving force control unit 33 using dedicated hardware instead of the computer program. There may be. Next, the driving force distribution control according to this embodiment will be described. In the following description, please refer to FIGS.

  FIG. 3 is a flowchart showing an example of a driving force distribution control procedure when the traveling device according to this embodiment is used. FIG. 4 is an explanatory diagram showing a control map used for driving force distribution control of the traveling device according to this embodiment. Next, an example in which driving force distribution control is executed between the left rear wheel (first driving wheel) 3l and the right rear wheel (second driving wheel) 3r of the vehicle 1 will be described.

  Here, the clutch rotation speed (the rotation speed of the clutch 13) of the control map 60 shown in FIG. 4 is set to the left side when the clutch 13 applies braking to the rotation of the sun gear 11S (that is, the clutch 13 generates a fastening force Fc). The rotation direction of the sun gear 11S (that is, the clutch 13) in the region where the driving force of the rear wheel 3l and the driving force of the right rear wheel 3r can be changed is negative. When the clutch rotational speed is in a positive region, that is, when the rotational direction of the clutch 13 is positive, the clutch 13 brakes the rotational speed of the sun gear 11S (decreases the rotational speed), that is, depending on the fastening force Fc of the clutch 13 This is an area where the driving force of the wheel 3l and the driving force of the right rear wheel 3r cannot be changed. The definition of the rotation direction of the clutch 13 is for convenience.

  In executing the driving force distribution control according to this embodiment, the driving condition determination unit 31 of the driving force distribution control device 30 (see FIG. 2) determines whether or not the condition for executing the driving force distribution control is satisfied ( Step S101). In the driving force distribution control, for example, when understeer is suppressed when the vehicle 1 is cornering, the driving force of the driving wheel outside the curve is increased and the driving force of the driving wheel inside the curve is decreased. Like that. Further, when oversteer is suppressed when the vehicle 1 is cornering, for example, the driving force of the driving wheel outside the curve is decreased and the driving force of the driving wheel inside the curve is increased. . This prevents the vehicle 1 from spinning due to oversteer.

  For example, when one of the driving wheels slips due to snow or ice, the driving force of the driving wheel in which the slip has occurred is reduced and the driving force of the driving wheel in which the slip has not occurred is increased. As a result, the driving force escaping to the drive wheel where the slip has occurred can be suppressed, so that the vehicle 1 can be reliably advanced. As described above, the driving force distribution control is executed when the turning performance of the vehicle 1 is controlled or the slip of the driving wheel is suppressed.

  For example, when suppressing understeer during cornering of the vehicle 1, the driving condition determination unit 31 determines the magnitude of the turning acceleration (lateral acceleration of the vehicle 1) acquired from the yaw sensor 46 and the steering angle sensor 42 (see FIG. 1) and steering. Based on the magnitude of the angle, it is determined whether or not the vehicle 1 is turning and is a condition for increasing the driving force of the driving wheels outside the curve. And the driving condition determination part 31 determines with it being in the conditions which perform driving force distribution control, when increasing the driving force of the driving wheel on the curve outer side. In determining whether to execute the driving force distribution control, the current vehicle speed V acquired from the vehicle speed sensor 43 and the torque Tm1 of the motor 12 obtained from the output command value for the motor 12 may be taken into account ( The same applies below).

  Further, when the driving force distribution control is executed when the driving wheel slips, for example, the left rear wheel acquired from the first driving shaft speed sensor 44l and the second driving shaft speed sensor 44r (see FIG. 1). When the rotational speed difference between 3l and the right rear wheel 3r exceeds a predetermined limit value, the driving condition determination unit 31 determines that an unacceptable slip has occurred in the driving wheel having a high rotational speed. In this case, the driving condition determination unit 31 determines that the condition for executing the driving force distribution control is satisfied.

  When the driving condition determination unit 31 determines that the condition for executing the driving force distribution control is not satisfied (step S101: No), the process returns to START, and the driving condition determination unit 31 continues to monitor the driving state of the vehicle 1. When the driving condition determination unit 31 determines that the condition for executing the driving force distribution control is satisfied (step S101: Yes), the control parameter calculation unit 32 of the driving force distribution control device 30 determines the current rotational speed of the clutch 13 ( Current clutch rotation speed Nc is calculated (step S102). Here, the current clutch rotational speed Nc is equal to the rotational speed of the sun gear 11S, and when the rotational speed of the ring gear 11R of the planetary gear unit 11 and the rotational speed of the carrier 11C are determined, the rotational speed of the sun gear 11S is uniquely determined. Is done.

  The rotational speed of the ring gear 11R is determined based on the rotational speed of the electric motor 12 detected by the resolver 45 or the rotational speed of the first drive shaft 16l to which the left rear wheel 3l is attached and the gear ratio gdl (the first power transmission gear 14 and the first (Gear ratio with the counter gear 14C). The rotation speed of the carrier 11C can be obtained from the rotation speed of the second drive shaft 16r to which the right rear wheel 3r is attached and the gear ratio gdr (the gear ratio between the second power transmission gear 15 and the second counter gear 15C). . The rotation speed of the first drive shaft 16l can be acquired from the first drive shaft rotation speed sensor 44l, and the rotation speed of the second drive shaft 16r can be acquired from the second drive shaft rotation speed sensor 44r.

  After obtaining the current clutch rotational speed Nc (step S102), the control parameter calculation unit 32 calculates the target rotational speed (target clutch rotational speed) Nc_p of the clutch 13 in the driving force distribution control (step S103). The target clutch rotational speed Nc_p is a control map shown in FIG. 4 showing the turning radius R and the driving force distribution ratio β (the left wheel driving force distribution ratio of the control map 60 and the driving force distribution ratio of the left rear wheel 3l) of the vehicle 1. It can be obtained by giving to 60.

  Since the current clutch rotational speed Nc indicates the rotational speed difference between the left rear wheel 3l and the right rear wheel 3r at the present time (during driving force distribution control), the turning radius R at the time of turning of the vehicle 1 is determined from the current clutch rotational speed Nc. Can be estimated. Further, the driving force distribution ratio β can be calculated from a yaw moment necessary for turning the vehicle 1 (hereinafter referred to as a requested yaw moment). The requested yaw moment is a deviation between the target yaw moment and the actual yaw moment, and is calculated by the control parameter calculation unit 32. Here, the target yaw moment is calculated by the control parameter calculator 32 based on information from the steering angle sensor 42 and the vehicle speed sensor 43. The actual yaw moment is detected by the yaw sensor 46.

  When the turning radius R of the vehicle 1 thus obtained and the driving force distribution ratio (left wheel driving force sharing ratio of the control map 60) β are given to the control map 60 (see FIG. 4), the corresponding clutch rotational speed, That is, the target clutch rotational speed Nc_p is obtained. This clutch rotational speed is the target clutch rotational speed Nc_p. For example, when the driving force distribution ratio β is 35% and the turning radius R = R3, the target clutch rotational speed Nc_p is about −200 rpm. The turning radius R at the time of turning of the vehicle 1 may be estimated based not only on the current clutch rotation speed Nc but also on the steering angle of the vehicle 1 and the actual yaw moment.

  Next, the operating condition determination unit 31 determines whether or not the target clutch rotational speed Nc_p (rpm) is larger than a predetermined threshold (clutch rotational speed threshold) Nc_s (rpm) (step S104). This is to determine whether or not the driving force of the left rear wheel 3l and the driving force of the right rear wheel 3r can be changed by adjusting the fastening force Fc of the clutch 13 and the torque Tm1 of the electric motor 12. As described above, by using the target clutch rotational speed Nc_p, it can be easily and reliably determined whether or not the driving force of the left rear wheel 3l and the driving force of the right rear wheel 3r can be changed.

  The clutch rotational speed threshold Nc_s is preferably a value smaller than 0 rpm, for example, −100 rpm to −50 rpm. From the control map 60 shown in FIG. 4, when the driving force distribution control is to be executed in a region where the target clutch rotational speed Nc_p is larger than 0 rpm, the clutch disk 13D of the clutch 13 is rotated in the direction opposite to the current rotational direction. There is a need. For this reason, in a region where the target clutch rotational speed Nc_p is larger than 0 rpm, the driving force distribution control cannot be performed only by adjusting the fastening force Fc of the clutch 13, but only by adjusting the fastening force Fc of the clutch 13. When the driving force distribution control is executed, the target clutch rotational speed Nc_p needs to be in an area of at least 0 rpm or less.

  Therefore, the clutch rotational speed threshold Nc_s may be 0 rpm. However, if the clutch rotation speed threshold Nc_s is set to 0 rpm due to the degree of wear of the drive wheels, the road surface condition, or torsional or backlash of the drive system, it is possible to actually control the drive force between the left and right drive wheels. It can be difficult. For this reason, the clutch rotation speed threshold Nc_s is preferably set to a value smaller than 0 rpm (for example, a value in the above range). In this way, problems caused by error factors such as the degree of wear of the drive wheels and the road surface condition can be avoided.

  When Nc_p ≦ Nc_s (step S104: No), the drive between the left rear wheel 3l and the right rear wheel 3r is avoided only by adjusting the fastening force Fc of the clutch 13 and avoiding the trouble caused by the error factor. Force distribution control can be realized. In this case, the control parameter calculation unit 32 calculates the target clutch torque Tcl_p from the current torque Tm1 of the electric motor 12 and the driving force distribution ratio obtained from the target yaw moment (step S105).

  Next, the control parameter calculation unit 32 sets the target clutch torque Tcl_p calculated in step S105 to the clutch torque command value (clutch torque command value) Tcl_c for the clutch 13 (step S106). Here, the clutch torque command value Tcl_c is converted into a command value for the clutch actuator 21 so that the clutch actuator 21 can supply the hydraulic pressure necessary for the clutch 13 to generate the target clutch torque Tcl_p. Then, the driving force control unit 33 of the driving force distribution control device 30 transmits a clutch torque command value Tcl_c to the clutch actuator 21 (step S110). Thus, the traveling device 10 drives the left rear wheel 3l and the right rear wheel 3r with a driving force distribution ratio for generating the target yaw moment.

  When Nc_p> Nc_s is satisfied (step S104: Yes), the adjustment between the engagement force Fc of the clutch 13 is performed only while adjusting the engagement force Fc between the left rear wheel 3l and the right rear wheel 3r while avoiding the problems caused by the error factors. Driving force distribution control is not possible. In this case, the control parameter calculation unit 32 first calculates the target clutch torque Tcl_p from the current torque Tm1 of the electric motor 12 and the driving force distribution ratio obtained from the target yaw moment (step S107).

  Next, the control parameter calculation unit 32 sets a value obtained by subtracting a predetermined torque value (clutch torque correction value) ΔTcl from the target clutch torque Tcl_p as a clutch torque command value Tcl_c for the clutch 13 (step S108). Here, the clutch torque correction value ΔTcl is a torque required for the clutch rotational speed Nc to be equal to or less than the clutch rotational speed threshold Nc_s, and the difference between the current clutch rotational speed Nc and the clutch rotational speed threshold Nc_s. Calculate based on

  Next, the control parameter calculation unit 32 calculates a braking force Tb_l of the left rear wheel 3l and a torque correction value (motor torque correction value) ΔTm1 of the motor 12 based on the calculated clutch torque correction value ΔTcl. This is to correct the clutch torque correction value ΔTcl with the braking force Tb_l of the left rear wheel 3l and the motor torque correction value ΔTm1 (step S109). For example, the clutch torque correction value ΔTcl is generated by the braking force Tb_l of the left rear wheel 3l, and the first drive shaft torque Tl (see formula (1)) lost by the braking of the left rear wheel 3l is generated by the motor 12. The motor torque correction value ΔTm1 is supplemented.

  In the configuration of the traveling device 10 according to this embodiment (see FIG. 1), the left rear wheel 3l is only adjusted by adjusting the fastening force Fc of the clutch 13 as the driving force sharing ratio of the left rear wheel 3l decreases. And the right rear wheel 3r shift to an area where the driving force distribution control is impossible (area shown by hatching in FIG. 4). That is, in the region where the driving force distribution control cannot be performed only by adjusting the fastening force Fc of the clutch 13, the driving force of the left rear wheel 3l cannot be made smaller than the target. In the traveling device 10 according to this embodiment, if the relationship between the left rear wheel 3l and the right rear wheel 3r is reversed, the driving force only by adjusting the fastening force Fc of the clutch 13 in the right rear wheel 3r. In an area where distribution control is impossible, the driving force of the right rear wheel 3r cannot be made smaller than the target.

  Therefore, in order to set the driving force of the left rear wheel 3l as the target value, the first braking device 17l generates the braking force Tb_l on the left rear wheel 3l to achieve the target driving force distribution ratio. On the other hand, when the braking force Tb_l is generated on the left rear wheel 3l by the first braking device 17l, the total driving force of the traveling device 10 is lower than before the braking force Tb_l is generated on the left rear wheel 3l. Therefore, the total driving force of the traveling device 10 reduced by braking the left rear wheel 3l is used as the torque of the motor 12 as the motor torque so that the total driving force of the traveling device 10 is constant before and after the driving force distribution control. Correction is performed by increasing the correction value ΔTm1.

  If the torque of the motor 12 is increased while maintaining the first drive shaft torque Tl obtained by braking the left rear wheel 3l with the braking force Tb_l, as can be seen from the equation (1), the motor 12 The clutch torque Tcl also increases according to the increase in torque. As a result, as can be seen from Equation (2), the second drive shaft torque Tr increases as the clutch torque Tcl increases, so the total drive force of the traveling device 10 is constant before and after the drive force distribution control. be able to.

  The driving force control unit 33 transmits a clutch torque command value Tcl_c to the clutch actuator 21 (step S110). Further, the driving force control unit 33 transmits a command value for generating the braking force Tb_l to the first braking actuator 22l for generating the braking force by the first braking device 17l, and the motor torque to the current torque Tm1. A command value for causing the electric motor 12 to generate a value (Tm1 + ΔTm1) obtained by adding the correction value ΔTm1 is transmitted to the inverter 23 (step S110). Thus, the traveling device 10 drives the left rear wheel 3l and the right rear wheel 3r with a driving force distribution ratio for generating the target yaw moment. Next, another control example of the traveling device 10 according to this embodiment will be described.

  FIG. 5 is a flowchart showing an example of another driving force distribution control procedure when the traveling device according to this embodiment is used. This driving force distribution control can be realized by the driving force distribution control device 30 shown in FIG. In executing the driving force distribution control, the driving condition determination unit 31 of the driving force distribution control device 30 (see FIG. 2) determines whether or not the condition for executing the driving force distribution control is satisfied (step S401).

  When the driving condition determination unit 31 determines that the condition for executing the driving force distribution control is not satisfied (step S401: No), the process returns to START, and the driving condition determination unit 31 continues to monitor the driving state of the vehicle 1. When the driving condition determination unit 31 determines that the condition for executing the driving force distribution control is satisfied (step S401: Yes), the control parameter calculation unit 32 of the driving force distribution control device 30 determines the current torque Tm1 of the electric motor 12 and The target clutch torque Tcl_p is calculated from the driving force distribution ratio obtained from the target yaw moment (step S402).

  Next, the control parameter calculator 32 sets the target clutch torque Tcl_p calculated in step S402 as the clutch torque command value Tcl_c for the clutch 13 (step S403). Here, the clutch torque command value Tcl_c is converted into a command value for the clutch actuator 21 so that the clutch actuator 21 can supply the hydraulic pressure necessary for the clutch 13 to generate the target clutch torque Tcl_p. Then, the driving force control unit 33 of the driving force distribution control device 30 transmits a clutch torque command value Tcl_c to the clutch actuator 21 (step S404). Thus, the traveling device 10 drives the left rear wheel 3l and the right rear wheel 3r with a driving force distribution ratio for generating the target yaw moment.

  Next, the operating condition determination unit 31 calculates the current rotation speed (current clutch rotation speed) Nc of the clutch 13 (step S405). The method for calculating the current clutch rotational speed Nc is as described above. When the current clutch rotational speed Nc is obtained (step S405), the operating condition determination unit 31 determines whether or not the current clutch rotational speed Nc is greater than a predetermined clutch rotational speed threshold Nc_s (rpm) (step S406). . The clutch rotation speed threshold value Nc_s is a value smaller than 0 rpm, and is set to, for example, −10 rpm to −100 rpm in consideration of disturbances during traveling.

  When Nc ≦ Nc_s (step S406: No), the driving force distribution control between the left rear wheel 3l and the right rear wheel 3r can be realized. When Nc> Nc_s (step S406: Yes), the driving force distribution control between the left rear wheel 3l and the right rear wheel 3r cannot be realized. In this case, the control parameter calculator 32 calculates a clutch torque correction value ΔTcl (step S407). The clutch torque correction value ΔTcl is as described above, and is calculated based on the difference between the current clutch rotational speed Nc and the clutch rotational speed threshold Nc_s.

  Then, the control parameter calculation unit 32 sets a value obtained by subtracting the clutch torque correction value ΔTcl from the latest target clutch torque Tcl_p (the target clutch torque Tcl_p calculated in step S402) at the current time as a new target clutch torque Tcl_p. (Step S408). The control parameter calculation unit 32 sets the set target clutch torque Tcl_p to the clutch torque command value Tcl_c transmitted to the clutch actuator 21.

  Next, the control parameter calculator 32 corrects the clutch torque correction value ΔTcl with the braking force Tb_l of the left rear wheel 3l and the motor torque correction value ΔTm1 (step S409). Therefore, the control parameter calculation unit 32 calculates the braking force Tb_l of the left rear wheel 3l and the torque correction value (motor torque correction value) ΔTm1 of the motor 12 based on the calculated clutch torque correction value ΔTcl.

  The driving force control unit 33 transmits the clutch torque command value Tcl_c set based on the target clutch torque Tcl_p set in step S408 to the clutch actuator 21 (step S410). Further, the driving force control unit 33 transmits a command value for generating the braking force Tb_l calculated in step S409 to the first braking actuator 22l (step S410). Then, the driving force control unit 33 transmits a command value for causing the electric motor 12 to generate a value (Tm1 + ΔTm1) obtained by adding the motor torque correction value ΔTm1 to the current torque Tm1 to the inverter 23 (step S410). Thus, the traveling device 10 drives the left rear wheel 3l and the right rear wheel 3r with a driving force distribution ratio for generating the target yaw moment.

  The driving force distribution control device 30 repeats steps S405 to S410 until Nc ≦ Nc_s. As described above, when Nc> Nc_s, the target clutch torque Tcl_p is changed based on the current clutch rotational speed Nc. Driving force distribution control can be realized. Next, control of the traveling device 10 during braking will be described.

  FIG. 6 is a flowchart showing a control procedure when the traveling apparatus according to this embodiment is decelerated. Control during deceleration of the traveling device 10 can be realized by the driving force distribution control device 30 (see FIG. 2) described above. When the vehicle 1 equipped with the traveling device 10 according to this embodiment decelerates, the driving condition determination unit 31 determines whether or not the brake (foot brake) is ON and power regeneration by the electric motor 12 is possible. (Step S201). Whether or not the brake is ON is determined, for example, when the brake sensor 41 generates an output, when the target deceleration is equal to or higher than a predetermined threshold, and the vehicle speed is equal to or higher than the predetermined speed, the brake is ON and the electric motor 12 It is determined that the regeneration of electric power is possible.

  When the brake is OFF or the electric power cannot be regenerated by the electric motor 12 (step S201: No), the necessary braking force cannot be obtained using the electric power regeneration by the electric motor 12. For this reason, both the left rear wheel 3l and the right rear wheel 3r of the traveling device 10 are braked using a mechanical brake (step S202). Here, the mechanical brake generates braking force by converting kinetic energy of the vehicle into thermal energy. In the traveling device 10, the first braking device 17l that brakes the left rear wheel 3l and the second braking device 17r that brakes the right rear wheel 3r correspond to mechanical brakes. The driving force control unit 33 sends a braking command to the first braking actuator 22l and the second braking actuator 22r to cause the first braking device 17l and the second braking device 17r to generate a braking force.

  When the brake is ON and the regeneration of electric power by the electric motor 12 is possible (step S201: Yes), first, the left rear wheel 3l and the right rear wheel 3r of the traveling device 10 are braked using a mechanical brake (step) S203). When regeneration by the electric motor 12 is performed, a command to change the fastening force Fc of the clutch 13 is sent. However, since the clutch 13 is operated by hydraulic pressure, a delay may occur until a predetermined hydraulic pressure is supplied to the clutch 13. . Due to this delay, the braking may be delayed. In this embodiment, the initial braking force is secured by the mechanical brake. The driving force control unit 33 sends a braking command to the first braking actuator 22l and the second braking actuator 22r to cause the first braking device 17l and the second braking device 17r to generate a braking force. At this time, the regenerative torque command for the electric motor 12 is set to zero.

  Next, the driving force control unit 33 releases the clutch 13 and commands the regenerative torque of the electric motor 12. Then, the braking force due to the regeneration of the electric motor 12 acts on the left rear wheel 31 by releasing the clutch 13. The driving force control unit 33 decreases the braking force of the first braking device 17l that brakes the left rear wheel 3l in accordance with the increase of the braking force due to regeneration of the electric motor 12 (step S204). In this way, the braking force of the first braking device 17l is adjusted based on the amount of power generated by the electric motor 12 due to regeneration.

  Thus, the second braking device 17r that brakes the right rear wheel 3r and the regenerative torque of the electric motor 12 that brakes the left rear wheel 3l are coordinated to control the braking force of the left rear wheel 3l and the right rear wheel. The braking force of the wheel 3r can be controlled to be the same. As a result, braking can be performed using the power regeneration of the electric motor 12, and the delay in the rise of the braking force can be minimized. Next, another control during deceleration of the traveling device according to this embodiment will be described.

  FIG. 7 is a flowchart showing another control procedure during deceleration of the traveling device according to this embodiment. This control can be realized by the driving force distribution control device 30 (see FIG. 2) described above. When the vehicle 1 equipped with the traveling device 10 according to this embodiment decelerates, the driving condition determination unit 31 determines whether or not the brake (foot brake) is ON and power regeneration by the electric motor 12 is possible. (Step S301).

  When the brake is OFF or the electric power regeneration by the electric motor 12 cannot be performed (step S301: No), the necessary braking force cannot be obtained by using the electric power regeneration by the electric motor 12. Therefore, both the left rear wheel 3l and the right rear wheel 3r of the traveling device 10 are braked using a mechanical brake (step S302). When the brake is ON and the regeneration of electric power by the electric motor 12 is possible (step S301: Yes), first, both the left rear wheel 3l and the right rear wheel 3r of the traveling device 10 are braked using a mechanical brake (step) S303).

  When regeneration by the electric motor 12 is performed, a command to change the fastening force Fc of the clutch 13 is sent. However, since the clutch 13 is operated by hydraulic pressure, a delay may occur until a predetermined hydraulic pressure is supplied to the clutch 13. . Due to this delay, the braking may be delayed. In this embodiment, the initial braking force is secured by the mechanical brake. The driving force control unit 33 sends a braking command to the first braking actuator 22l and the second braking actuator 22r to cause the first braking device 17l and the second braking device 17r to generate a braking force. At this time, the regenerative torque command for the electric motor 12 is set to zero.

  Next, the driving force control unit 33 engages the clutch 13 (step S304) and commands the regenerative torque of the electric motor 12. As a result, the braking force generated by the power regeneration of the electric motor 12 is applied to both the left rear wheel 3l and the right rear wheel 3r. Next, the driving force controller 33 controls the first braking device 17l that brakes the left rear wheel 3l and the second braking device 17r that brakes the right rear wheel 3r in accordance with an increase in braking force due to regeneration of the electric motor 12. Both powers are reduced (step S305). In this way, the braking force of the first braking device 17l and the second braking device 17r is adjusted based on the amount of electric power generated by the electric motor 12 due to regeneration.

  As described above, the first brake device 17l that brakes the left rear wheel 3l and the second brake device 17r that brakes the right rear wheel 3r and the regenerative torque of the motor 12 are controlled in a coordinated manner so that the electric power is generated by the motor 12. And the braking force of the left rear wheel 3l and the braking force of the right rear wheel 3r can be controlled to be the same.

  As described above, in this embodiment, the power split mechanism including the first rotating element, the second rotating element, and the third rotating element, and the power generating means that drives the first drive wheel and is connected to the first rotating element. And a driving force adjustment that changes the torque of both driving wheels between the first driving wheel and the second driving wheel to which power is transmitted from the second rotating element by applying braking to the rotation of the third rotating element. Means. Thus, each driving force can be changed between different driving wheels by a single power generation means. Thereby, when providing the driving force difference to the plurality of driving wheels, the apparatus can be made compact and the mounting property to the vehicle can be improved. In addition, what is provided with the structure similar to the structure disclosed by this embodiment has an effect | action and effect similar to this embodiment.

  As described above, the traveling device according to the present invention is useful when different driving forces are used between different driving wheels, and is particularly suitable for making the device compact and improving the mountability on a vehicle. .

It is explanatory drawing which shows the vehicle provided with the traveling apparatus which concerns on this embodiment, and the traveling apparatus which concerns on this embodiment. It is a conceptual diagram which shows the structure of the driving force distribution control apparatus which concerns on this embodiment. It is a flowchart which shows an example of the driving force distribution control procedure at the time of using the traveling apparatus which concerns on this embodiment. It is explanatory drawing which shows the control map used for the driving force distribution control of the traveling apparatus which concerns on this embodiment. It is a flowchart which shows an example of the other driving force distribution control procedure at the time of using the traveling apparatus which concerns on this embodiment. It is a flowchart which shows the procedure of the control at the time of deceleration of the traveling apparatus which concerns on this embodiment. It is a flowchart which shows the procedure of the other control at the time of the deceleration of the traveling apparatus which concerns on this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle 2l Left front wheel 2r Right front wheel 3l Left rear wheel 3r Right rear wheel 4 Front wheel drive device 6 Handle 7 Accelerator 8 Brake 9 Car power supply 10 Traveling device 11 Planetary gear device 11C Carrier 11R Ring gear 11S Sun gear 12 Electric motor 13 Clutch 16l Drive shaft 16r Second drive shaft 17l First brake device 17r Second brake device 20B Braking oil pressure generator 20C Clutch oil pressure generator 21 Clutch actuator 22l First brake actuator 22r Second brake actuator 23 Inverter 30 Drive Force distribution control device 31 Operating condition determination unit 32 Control parameter calculation unit 33 Driving force control unit 40 Accelerator opening sensor 41 Brake sensor 42 Steering angle sensor 43 Vehicle speed sensor 44l First drive shaft rotational speed sensor 44r Second Drive shaft speed sensor 45 Resolver 46 Yaw sensor 60 Control map

Claims (6)

It is mounted on a vehicle and changes the driving force between different driving wheels.
A power split mechanism comprising a first rotating element, a second rotating element, and a third rotating element;
Power generating means connected to the first rotating element;
A first drive wheel driven by power transmitted from the power generation means;
A second drive wheel driven by the power of the power generating means transmitted through the second rotating element;
By applying braking to the rotation of the third rotating element, the driving force transmitted from the power generation means to the first driving wheel and the second driving wheel are transmitted to the second driving wheel via the second rotating element. Driving force adjusting means for changing the driven driving force;
A traveling device comprising: The power split mechanism is a planetary gear device having a sun gear, a carrier, and a ring gear as rotating elements,
The first rotating element is the ring gear or the sun gear, the second rotating element is a carrier, and the third rotating element is the sun gear or the ring gear that is different from the first rotating element. The traveling device according to claim 1. The third rotating element in a region where the driving force of the first driving wheel and the driving force of the second driving wheel can be changed by applying braking to the rotation of the third rotating element by the driving force adjusting means. The rotation direction of is negative,
A target rotational speed of the third rotating element set based on a driving force distribution ratio between the first driving wheel and the second driving wheel required from a target yaw moment that is a target of the vehicle is determined in advance. If it is greater than the predetermined threshold,
Using the correction torque of the third rotation element calculated based on the difference between the target rotation speed and the predetermined threshold, the first drive wheel and the second drive required from the target yaw moment The torque generated by the power generation means is changed based on the correction torque while correcting the target torque of the third rotation element set based on a driving force distribution ratio with the wheel. The traveling device according to 1 or 2.   4. The traveling device according to claim 3, further comprising a braking unit that brakes a driving force that cannot be reduced by the first driving wheel and the second driving wheel. The power generation means is an electric motor, and when braking the vehicle,
After braking using the first braking device that brakes the first driving wheel and the second braking device that brakes the second driving wheel, the driving force adjusting means brakes the third rotating element. After releasing the power to regenerate the electric motor,
The traveling device according to any one of claims 1 to 4, wherein a braking force of the first braking device is adjusted based on an amount of electric power generated by the electric motor. The power generation means is an electric motor, and when braking the vehicle,
After braking using the first braking device that brakes the first driving wheel and the second braking device that brakes the second driving wheel, the driving force adjusting means brakes the third rotating element. To regenerate power in the motor,
The braking force of the first braking device and the braking force of the second braking device are adjusted based on the amount of electric power generated by the electric motor. Traveling device.

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