JP6274837B2 - Electric vehicle - Google Patents

Description

  The present invention relates to an electric vehicle provided with a left wheel driving device that drives a left wheel and a right wheel driving device that drives a right wheel.

  Patent Document 1 discloses a left wheel drive device having a first electric motor that drives a left wheel of a vehicle, and a first planetary gear type transmission that is provided on a power transmission path between the first electric motor and the left wheel. A right wheel drive device comprising: a second motor for driving the right wheel of the vehicle; and a second planetary gear type transmission provided on a power transmission path between the second motor and the right wheel. A drive device is described. In the first and second planetary gear type transmissions, the first and second electric motors are connected to the sun gear, the left wheel and the right wheel are connected to the planetary carrier, respectively, and the ring gears are connected to each other. Further, the vehicle drive device is provided with a brake means and a one-way clutch for braking the rotation of the ring gear by releasing or fastening the connected ring gear.

  In Patent Document 1, the vehicle drive device configured as described above is used as a rear wheel drive device, and another front wheel drive device using an engine as a drive source is provided on the front wheels, and the front wheel drive is performed at a high vehicle speed with high engine efficiency. The first and second motors are prevented from over-rotating by using the device as a drive source and switching the brake means of the rear wheel drive device from the engaged state to the released state.

  In a state where free rotation of the ring gear is allowed (hereinafter also referred to as a ring-free state), forward torque or reverse torque is generated in the first motor, and the first motor is applied to the second motor. And the absolute values are equal to each other so that torque in the opposite direction (reverse direction or forward direction) is generated. A desired yaw moment can be generated by generating a left-right differential torque (hereinafter also referred to as ring-free control).

  In this ring-free control, since the ring gear is allowed to rotate freely, even if the planetary carrier connected to the left and right rear wheels increases in speed according to the vehicle speed, the sun gear does not depend on the planetary carrier. The rotational speeds of the first and second electric motors connected to can be freely set. Therefore, in the ring-free state, the rotation speeds of the first and second motors are not proportional to the vehicle speed, and the motor torque that can be output by the first and second motors can be freely set up to the upper limit torque of the motor determined by the motor specifications. It becomes possible to do.

  In Patent Document 1, when switching from the ring lock state to the ring free state, the ring free limit torque, which is the limit torque of the first and second motors after switching, is used, for example, in the motor specification in the ring lock state at the time of switching. The engagement state of the brake means is set such that the absolute value is larger than the upper limit torque of the first and second electric motors determined by the formula, and the torque generated by the first and second electric motors is less than the ring free limit torque. It is described that a sudden change in torque at the time of transition from the state to the released state is suppressed.

JP 2013-2105018 A

  However, if an abnormality occurs in the torque command to the first and second motors for some reason, there is a possibility that a sudden torque change may occur.

  This invention is made | formed in view of the said subject, and aims at providing the electric vehicle excellent in redundancy.

In order to achieve the above object, the invention described in claim 1
On the power transmission path between the first electric motor (for example, the first electric motor 2A in the embodiment described later) that drives the left wheel (for example, the left rear wheel LWr in the embodiment described later), and the first motor and the left wheel. A left wheel drive device having a first transmission (for example, a first planetary gear speed reducer 12A in an embodiment described later) and a right wheel (for example, a right rear wheel RWr in an embodiment described later). And a second transmission (for example, an embodiment described later) provided on a power transmission path between the second motor (for example, a second motor 2B of the embodiment described later) and the second motor and the right wheel. A second planetary gear speed reducer 12B), and a right wheel drive device having control means for controlling the first electric motor and the second electric motor (for example, a control system 100 of an embodiment described later). Electric vehicle equipped (for example, in the embodiment described later A two 3),
The first and second transmissions each have first to third rotating elements,
The first electric motor is connected to the first rotating element of the first transmission (for example, a sun gear 21A in an embodiment described later),
The second electric motor is connected to the first rotating element of the second transmission (for example, a sun gear 21B in an embodiment described later),
The left wheel is connected to the second rotating element of the first transmission (for example, a planetary carrier 23A in an embodiment described later),
The right wheel is connected to the second rotating element of the second transmission (for example, a planetary carrier 23B in an embodiment described later);
The third rotation element of the first transmission (for example, a ring gear 24A in an embodiment described later) and the third rotation element of the second transmission (for example, a ring gear 24B of an embodiment described later) are connected to each other. ,
The electric vehicle can be released and engaged, and further includes rotation restricting means (for example, hydraulic brakes 60A and 60B and a one-way clutch 50 according to an embodiment described later) that restricts the rotation of the third rotating element by being engaged. Prepared,
The control unit further includes a state switching unit (for example, a BRK state switching unit 94 in an embodiment described later) that switches the rotation regulating unit to release and fastening.
The state switching means includes a vehicle speed correlation amount that correlates with the vehicle speed of the electric vehicle (for example, a vehicle speed of an embodiment described later, rotation state amount related values of the first and second electric motors 2A, 2B, left and right rear wheels LWr, RWr). On the basis of the rotation state quantity related value and the rotation state quantity related value of the front wheel Wf), the release and engagement of the rotation restricting means (for example, hydraulic brakes 60A and 60B in the embodiments described later) are switched.
The control means includes
Third rotation element rotation state acquisition means for acquiring the rotation state of the third rotation element (for example, ring gear rotation state acquisition units 91 and 95 of embodiments described later);
When the third rotation element rotation state acquisition means acquires that the rotation restriction means is released and the third rotation element is in a rotation free state (for example, a ring free state in an embodiment described later), 1st limiting means (for example, the 1st limit of the below-mentioned embodiment) which controls the torque of 1 motor and the 2nd motor so that it may become in a predetermined limit torque (for example, the 1st ring free limit torque of the below-mentioned embodiment) Part 97),
A second circuit that is provided separately from the first limiting means and controls the torque of the first motor and the second motor to be within a predetermined limiting torque (for example, a second ring-free limiting torque in an embodiment described later). and limiting means (e.g., second restriction portion 93 of the embodiment described later), it was closed,
The first limiting means acquires the rotation free state by first vehicle speed acquisition means (for example, a rotation speed sensor 85 of an embodiment described later) that acquires the vehicle speed correlation amount;
The second restriction means is provided separately from the first vehicle speed acquisition means, and the rotation free state is set by a second vehicle speed acquisition means (for example, a wheel speed sensor 83 in an embodiment described later) that acquires the vehicle speed correlation amount. It is characterized by acquiring .

The invention according to claim 2, in addition to the configuration according to claim 1,
The left wheel and the right wheel are the left wheel and the right wheel of either the front wheel or the rear wheel of the electric vehicle (for example, the rear wheel Wr in the embodiment described later), and the front wheel and the rear wheel of the electric vehicle. When the other wheel is the other wheel (for example, a front wheel Wf in an embodiment described later)
The electric vehicle includes another drive device that drives the other wheel (for example, a front wheel drive device 6 in an embodiment described later),
The first vehicle speed acquisition means acquires the vehicle speed correlation amount based on a rotation state amount of the other drive device (for example, a detected value of a rotation speed sensor of a transmission 7 in an embodiment described later),
The second vehicle speed acquisition means acquires the vehicle speed correlation amount based on a rotation state amount of the one wheel (for example, a wheel speed sensor detection value of a rear wheel Wr in an embodiment described later).

In addition to the configuration described in claim 1 or 2 , the invention described in claim 3
The second restricting means is arranged on the circuit of the control means so as to be closest to the first and second electric motors in the signal flow direction.

Moreover, in addition to the structure of Claim 1 or 2 , the invention of Claim 4 adds to the structure of Claim 1 or 2 ,
The second limiting means outputs control signals for the first and second motors,
The first limiting means can communicate with the second limiting means,
The second limiting means includes a limiting torque acquired by the second limiting means (for example, a second ring-free limiting torque in an embodiment described later) and a limiting torque transmitted from the first limiting means (for example, an implementation described later). First ring-free limiting torque), and when the limiting torque of the first limiting means is different from the limiting torque of the second limiting means, the first and second limiting torques are based on the smaller limiting torque. It is characterized by controlling two electric motors.

Moreover, this invention provides the following aspects.
(1) a wheel (for example, a left rear wheel Lr in an embodiment described later);
Driving sources for driving the wheels (for example, first and second electric motors 2A and 2B in the embodiments described later);
Control means for controlling the drive source (for example, a control system 100 of an embodiment described later);
On the power transmission path between the drive source and the wheel, connecting / disconnecting means (for example, hydraulic brakes 60A and 60B in the embodiments described later) that can be released and fastened and switches the power transmission path between a disconnected state and a connected state. Direction clutch 50), and an electric vehicle (for example, a vehicle 3 in an embodiment described later),
When the connecting / disconnecting means is released and the power transmission path is in the disconnected state, an upstream rotational state acquiring means (for example, described later) acquires an upstream rotational state amount that is on the drive source side of the connecting / disconnecting means. Resolver 20A, 20B) of the embodiment of
Downstream rotation state acquisition means (for example, a wheel speed sensor 83 and a rotation speed sensor 85 of the embodiment described later) that acquires a downstream rotation state amount that is on the wheel side of the connection / disconnection means,
The control means controls the torque generated by the drive source based only on the downstream rotational state amount acquired by the downstream rotational state acquisition means in the shut-off state.

(2) The electric vehicle according to (1) ,
The control means limits the torque generated by the drive source based only on the downstream rotational state amount acquired by the downstream rotational state acquisition means in the shut-off state.

According to the first aspect of the present invention, when the third rotating element is in a freely rotating state, the torque limit of the first and second motors does not depend on the structural limit but depends on the control limit. By making the torque limit redundant, it is possible to reliably prevent disturbance of vehicle behavior due to generation of unnecessary motor torque.
Further, by performing release control of the rotation restricting means based on the vehicle speed correlation amount, it is possible to suppress over-rotation of the first and second motors. Further, since the vehicle speed correlation amount can be obtained in various ways, the redundancy is further improved.

According to the second aspect of the present invention, the vehicle speed correlation amount is obtained based on the rotation state amount of the other driving device correlated with the rotation speed of the other wheel and the rotation state amount of the one wheel, so that the vehicle speed is more redundant. Improves.

According to the third aspect of the present invention, it is possible to reliably limit the motor torque even if an abnormality of the circuit itself or an abnormality of communication occurs upstream of the second limiting means.

According to the invention described in claim 4 , even if either one of the first vehicle speed acquisition means and the second vehicle speed acquisition means fails, the first and second electric motors are based on the smaller limit torque. By controlling this, even if a control failure occurs, the motor torque can be generated within the smaller limit torque.

Further , according to the aspects described in the above (1) and (2) , when the power transmission path is in the cut-off state, the torque limit of the motor does not depend on the structural limit but depends on the control limit. By making the torque limit redundant, it is possible to reliably prevent disturbance of vehicle behavior due to generation of unnecessary motor torque.

1 is a block diagram showing a schematic configuration of a hybrid vehicle that is an embodiment of a vehicle according to the present invention. It is a longitudinal cross-sectional view of one Embodiment of a rear-wheel drive device. FIG. 3 is a partially enlarged view of the rear wheel drive device shown in FIG. 2. It is the table | surface which described the relationship between the front-wheel drive device and rear-wheel drive device in a vehicle state with the operation state of the electric motor. It is a speed alignment chart of the rear-wheel drive device in a stop. It is a speed alignment chart of the rear-wheel drive device at the time of forward low vehicle speed. It is a speed alignment chart of the rear-wheel drive device at the time of forward vehicle speed. It is a speed alignment chart of the rear-wheel drive device at the time of deceleration regeneration. It is a speed alignment chart of the rear-wheel drive device at the time of forward high vehicle speed. It is a speed alignment chart of the rear-wheel drive device at the time of reverse drive. It is a timing chart in vehicle travel. (A) is a speed alignment chart of the rear wheel drive device at the time of target torque control in ring-free control, and (b) is a speed alignment graph of the rear wheel drive device at the time of target rotation speed control in ring-free control. It is. It is a speed alignment chart of the rear-wheel drive device when the target torque control and the target rotation speed control in the ring-free control are performed simultaneously. FIG. 4 is a time collinear diagram of a rear wheel drive device in the case of transition from a ring lock state to a ring free state, in which (a) is a speed collinear diagram during ring lock control, and (b) is It is a speed nomograph when the target torque control and the target rotational speed control in the ring free control are simultaneously performed, and (c) is a speed nomograph in the target torque control in the ring free control. (A) is a figure which shows the relationship between the vehicle speed and motor torque in a ring lock state, (b) is a figure which shows the relationship between the vehicle speed and motor torque in a ring free state. It is a figure which shows the relationship between the vehicle speed at the time of switching from a ring lock state to a ring free state at a certain vehicle speed, and the ring free limit torque (RF limit torque) after switching in the ring lock state at the time of switching This is a case where the absolute value is set larger than the upper limit torque (MOT upper limit torque) of the first and second motors. It is a figure which shows the relationship between the vehicle speed at the time of switching from a ring lock state to a ring free state at a certain vehicle speed, and the ring free limit torque (RF limit torque) after switching in the ring lock state at the time of switching This is a case where the absolute value is set larger than the ring lock limit torque (RL limit torque) of the first and second motors. It is a figure which shows the relationship between the vehicle speed at the time of switching from a ring lock state to a ring free state at a certain vehicle speed, and the ring free limit torque (RF limit torque) after switching in the ring lock state at the time of switching This is a case where the upper limit torque (MOT upper limit torque) of the first and second motors is set to a value approximately equal to the first and second motors. It is a figure which shows the relationship between the vehicle speed at the time of switching from a ring lock state to a ring free state at a certain vehicle speed, and the ring free limit torque (RF limit torque) after switching in the ring lock state at the time of switching This is a case where the ring lock limit torque (RL limit torque) of the first and second motors is set to a value that is substantially equal. It is a figure which shows the relationship between the vehicle speed at the time of switching from a ring lock state to a ring free state at a certain vehicle speed, and the ring free limit torque (RF limit torque) after switching in the ring lock state at the time of switching This is a case where the value is changed from a value substantially equal to the upper limit torque (MOT upper limit torque) of the first and second motors. It is a block diagram of the control system of one Embodiment of this invention.

First, an embodiment of an electric vehicle according to the present invention will be described with reference to FIGS.
An electric vehicle (hereinafter referred to as a vehicle) according to the present invention uses an electric motor as a drive source for driving an axle, and can be mounted with a drive system as shown in FIG. 1, for example.
A vehicle 3 shown in FIG. 1 is a hybrid vehicle having a drive device 6 (hereinafter referred to as a front wheel drive device) in which an internal combustion engine 4 and an electric motor 5 are connected in series at the front portion of the vehicle. Is transmitted to the front wheels Wf via the transmission 7, while the power of the driving device 1 (hereinafter referred to as a rear wheel driving device) provided at the rear of the vehicle separately from the front wheel driving device 6 is the rear wheel Wr. (RWr, LWr). The electric motor 5 of the front wheel drive device 6 and the first and second electric motors 2A and 2B of the rear wheel drive device 1 on the rear wheel Wr side are connected to the battery 9, and supply power from the battery 9 and energy to the battery 9 Regeneration is possible. Reference numeral 100 denotes a control system for performing various controls of the entire vehicle.

  FIG. 2 is a longitudinal sectional view of the entire rear wheel drive device 1. In FIG. 2, 10A and 10B are left and right axles on the rear wheel Wr side of the vehicle 3, and are coaxial in the vehicle width direction. Is arranged. The reduction gear case 11 of the rear wheel drive device 1 is formed in a substantially cylindrical shape, and includes therein first and second electric motors 2A and 2B for driving an axle, and the first and second electric motors 2A and 2B. The first and second planetary gear type speed reducers 12A and 12B that decelerate the drive rotation are disposed coaxially with the axles 10A and 10B. The first motor 2A and the first planetary gear type speed reducer 12A function as a left wheel driving device that drives the left rear wheel LWr, and the second motor 2B and the second planetary gear type speed reducer 12B drive the right rear wheel RWr. The first electric motor 2A and the first planetary gear type speed reducer 12A, the second electric motor 2B and the second planetary gear type speed reducer 12B function in the vehicle width direction in the speed reducer case 11. They are arranged symmetrically.

  The stators 14A and 14B of the first and second electric motors 2A and 2B are respectively fixed inside the left and right ends of the speed reducer case 11, and the annular rotors 15A and 15B are rotatable on the inner peripheral sides of the stators 14A and 14B. Is arranged. Cylindrical shafts 16A and 16B surrounding the outer periphery of the axles 10A and 10B are coupled to the inner peripheral portions of the rotors 15A and 15B, and the cylindrical shafts 16A and 16B are decelerated so as to be coaxially rotatable with the axles 10A and 10B. The machine case 11 is supported by end walls 17A and 17B and intermediate walls 18A and 18B via bearings 19A and 19B. Further, the rotational position information of the rotors 15A and 15B is transferred to the control walls of the first and second electric motors 2A and 2B on the end walls 17A and 17B of the reduction gear case 11 on the outer periphery on one end side of the cylindrical shafts 16A and 16B. Resolvers 20A and 20B are provided for feedback to (not shown).

  The first and second planetary gear speed reducers 12A and 12B include sun gears 21A and 21B, a plurality of planetary gears 22A and 22B meshed with the sun gears 21A and 21B, and planetary gears 22A and 22B that support these planetary gears 22A and 22B. Carriers 23A, 23B and ring gears 24A, 24B meshed with the outer peripheral sides of the planetary gears 22A, 22B. The driving forces of the first and second electric motors 2A, 2B are input from the sun gears 21A, 21B and decelerated. A driving force is output through the planetary carriers 23A and 23B.

  The sun gears 21A and 21B are formed integrally with the cylindrical shafts 16A and 16B. Further, for example, as shown in FIG. 3, the planetary gears 22A and 22B include large-diameter first pinions 26A and 26B that are directly meshed with the sun gears 21A and 21B, and a second pinion having a smaller diameter than the first pinions 26A and 26B. The first and second pinions 26A and 26B and the second pinions 27A and 27B are integrally formed in a state of being coaxially and offset in the axial direction. The planetary gears 22A and 22B are supported by the planetary carriers 23A and 23B, and the planetary carriers 23A and 23B are supported so as to be integrally rotatable with the axially inner ends extending inward in the radial direction and being spline-fitted to the axles 10A and 10B. Along with the bearings 33A and 33B, the intermediate walls 18A and 18B are supported.

  The intermediate walls 18A and 18B separate the motor housing space for housing the first and second motors 2A and 2B from the speed reducer space for housing the first and second planetary gear speed reducers 12A and 12B. Are bent so that the axial distance between them increases toward the inner diameter side. Bearings 33A and 33B for supporting the planetary carriers 23A and 23B are disposed on the inner diameter side of the intermediate walls 18A and 18B and on the first and second planetary gear speed reducers 12A and 12B, and the intermediate walls 18A and 18B are disposed. Bus rings 41A and 41B for the stators 14A and 14B are arranged on the outer diameter side of 18B and the first and second electric motors 2A and 2B (see FIG. 2).

  The ring gears 24A and 24B are disposed opposite to each other at gears 28A and 28B whose inner peripheral surfaces are meshed with the second pinions 27A and 27B having a small diameter, and smaller in diameter than the gear parts 28A and 28B, at an intermediate position of the speed reducer case 11. Small-diameter portions 29A and 29B, and connecting portions 30A and 30B that connect the axially inner ends of the gear portions 28A and 28B and the axially outer ends of the small-diameter portions 29A and 29B in the radial direction. . In the case of this embodiment, the maximum radii of the ring gears 24A and 24B are set to be smaller than the maximum distance from the center of the axles 10A and 10B of the first pinions 26A and 26B. The small diameter portions 29A and 29B are spline-fitted to an inner race 51 of a one-way clutch 50, which will be described later, and the ring gears 24A and 24B are configured to rotate integrally with the inner race 51 of the one-way clutch 50.

  By the way, a cylindrical space is secured between the speed reducer case 11 and the ring gears 24A and 24B, and hydraulic brakes 60A and 60B that constitute braking means for the ring gears 24A and 24B are provided in the space portions in the first pinion 26A, 26B overlaps in the radial direction and overlaps with the second pinions 27A and 27B in the axial direction. The hydraulic brakes 60A and 60B include a plurality of fixed plates 35A and 35B that are spline-fitted to the inner peripheral surface of a cylindrical outer diameter side support portion 34 that extends in the axial direction on the inner diameter side of the speed reducer case 11, a ring gear 24A, A plurality of rotating plates 36A, 36B that are spline-fitted on the outer peripheral surface of 24B are alternately arranged in the axial direction, and these plates 35A, 35B, 36A, 36B are fastened and released by the annular pistons 37A, 37B. It is like that. The pistons 37 </ b> A and 37 </ b> B are formed between the left and right dividing walls 39 extending from the intermediate position of the reduction gear case 11 to the inner diameter side, and the outer diameter side support portion 34 and the inner diameter side support portion 40 connected by the left and right division walls 39. The pistons 37A and 37B are moved forward by introducing high pressure oil into the cylinder chambers 38A and 38B, and the oil is discharged from the cylinder chambers 38A and 38B. The pistons 37A and 37B are moved backward. The hydraulic brakes 60A and 60B are connected to the electric oil pump 70 (see FIG. 1).

  More specifically, the pistons 37A and 37B have first piston walls 63A and 63B and second piston walls 64A and 64B in the axial direction, and the piston walls 63A, 63B, 64A and 64B are cylindrical. Are connected by inner peripheral walls 65A and 65B. Therefore, an annular space that opens radially outward is formed between the first piston walls 63A and 63B and the second piston walls 64A and 64B. This annular space is formed on the inner periphery of the outer wall of the cylinder chambers 38A and 38B. It is partitioned in the axial direction left and right by partition members 66A and 66B fixed to the surface. A space between the left and right dividing walls 39 of the reduction gear case 11 and the second piston walls 64A and 64B is a first working chamber S1 into which high-pressure oil is directly introduced, and between the partition members 66A and 66B and the first piston walls 63A and 63B. Is a second working chamber S2 that is electrically connected to the first working chamber S1 through through holes formed in the inner peripheral walls 65A and 65B. The second piston walls 64A and 64B and the partition members 66A and 66B are electrically connected to the atmospheric pressure.

  In the hydraulic brakes 60A and 60B, oil is introduced into the first working chamber S1 and the second working chamber S2 from a hydraulic circuit (not shown) and acts on the first piston walls 63A and 63B and the second piston walls 64A and 64B. The fixed plates 35A and 35B and the rotating plates 36A and 36B can be pressed against each other by the pressure of. Therefore, since the large pressure receiving area can be gained by the first and second piston walls 63A, 63B, 64A, 64B on the left and right in the axial direction, the fixing plates 35A, 35B A large pressing force against the rotating plates 36A and 36B can be obtained.

  In the case of the hydraulic brakes 60A and 60B, the fixed plates 35A and 35B are supported by the outer diameter side support portion 34 extending from the reduction gear case 11, while the rotation plates 36A and 36B are supported by the ring gears 24A and 24B. When the plates 35A, 35B, 36A, and 36B are pressed by the pistons 37A and 37B, the frictional engagement between the plates 35A, 35B, 36A, and 36B causes a braking force to act on the ring gears 24A and 24B, and is fixed (locked). When the fastening by the pistons 37A and 37B is released from this state, the ring gears 24A and 24B are allowed to freely rotate.

  That is, the hydraulic brakes 60A and 60B lock the ring gears 24A and 24B at the time of engagement, make the power transmission path between the first and second electric motors 2A and 2B and the rear wheel Wr connectable to the power transmission, and the ring gear at the time of release. The rotation of 24A, 24B is allowed, and the power transmission path between the first and second electric motors 2A, 2B and the rear wheel Wr is set to a cut-off state where power cannot be transmitted.

  Also, a space is secured between the coupling portions 30A and 30B of the ring gears 24A and 24B facing each other in the axial direction, and only power in one direction is transmitted to the ring gears 24A and 24B in the space to transmit power in the other direction. A one-way clutch 50 is arranged to be shut off. The one-way clutch 50 has a large number of sprags 53 interposed between an inner race 51 and an outer race 52. The inner race 51 is connected to the small diameter portions 29A, 29B of the ring gears 24A, 24B by spline fitting. It is configured to rotate integrally. That is, the ring gear 24A and the ring gear 24B are connected to each other by the inner race 51 so as to be integrally rotatable. The outer race 52 is positioned by the inner diameter side support portion 40 and is prevented from rotating.

  The one-way clutch 50 is configured to engage and lock the rotation of the ring gears 24A and 24B when the vehicle 3 moves forward with the power of the first and second electric motors 2A and 2B. More specifically, the one-way clutch 50 is used when torque in the forward direction (rotation direction when the vehicle 3 is advanced) on the first and second electric motors 2A, 2B side is input to the rear wheel Wr side. The engaged state is established, and when the reverse torque on the first and second motors 2A, 2B side is input to the rear wheel Wr, the disengaged state is established, and the forward torque on the rear wheel Wr side is the first. And when engaged with the second motor 2A, 2B, the engaged state when the reverse torque on the rear wheel Wr side is input to the first and second motors 2A, 2B. It becomes. In other words, the one-way clutch 50 allows one-way rotation of the ring gears 24A and 24B by the reverse torque of the first and second motors 2A and 2B when not engaged, and the first and second motors when engaged. The reverse rotation of the ring gears 24A and 24B by the forward torque of 2A and 2B is restricted. The reverse torque refers to torque in a direction that increases reverse rotation or torque in a direction that decreases forward rotation.

  Thus, in the rear wheel drive device 1 of the present embodiment, the one-way clutch 50 and the hydraulic brakes 60A and 60B are provided in parallel on the power transmission path between the first and second electric motors 2A and 2B and the rear wheel Wr. ing. It is not necessary to provide two hydraulic brakes 60A and 60B, and only one hydraulic brake may be provided and the other space may be used as a breather chamber.

  Here, the control system 100 (see FIG. 1) is a control device for performing various controls of the entire vehicle. The control system 100 includes wheel speed sensor detection values and motor rotations of the first and second motors 2A and 2B. A number sensor detection value, steering angle, accelerator pedal opening AP, shift position, state of charge (SOC) in the battery 9, oil temperature, and the like are input, while the control system 100 receives a signal for controlling the internal combustion engine 4, A signal for controlling the first and second electric motors 2A and 2B, a signal for controlling the hydraulic brakes 60A and 60B, a control signal for controlling the electric oil pump 70, and the like are output.

  That is, the control system 100 serves as a state switching unit that switches between a function as an electric motor control unit that controls the first and second electric motors 2A and 2B and an engaged state and a released state of the hydraulic brakes 60A and 60B as a rotation regulating unit. It has at least the function.

  FIG. 4 shows the relationship between the front wheel drive device 6 and the rear wheel drive device 1 in each vehicle state together with the operating states of the first and second electric motors 2A and 2B. In the figure, the front unit represents the front wheel drive device 6, the rear unit represents the rear wheel drive device 1, the rear motor represents the first and second electric motors 2A and 2B, OWC represents the one-way clutch 50, and BRK represents the hydraulic brakes 60A and 60B. 5 to 10 and FIGS. 12 to 14 show speed collinear charts in the respective states of the rear wheel drive device 1. The LMOT is the first motor 2A, the RMOT is the second motor 2B, and the left S and C are The sun gear 21A of the first planetary gear speed reducer 12A connected to the first electric motor 2A, the planetary carrier 23A of the first planetary gear speed reducer 12A, and S and C on the right side are the same as those of the second planetary gear speed reducer 12B. The planetary carrier 23B, R of the sun gear 21B, the second planetary gear speed reducer 12B, the ring gears 24A, 24B, BRK of the first and second planetary gear speed reducers 12A, 12B are the hydraulic brakes 60A, 60B, OWC are the one-way clutch 50. Represents. In the following description, the rotation direction of the sun gears 21A and 21B when the vehicle is advanced by the first and second electric motors 2A and 2B is defined as the forward direction. Also, in the figure, from the stationary state, the upper direction is forward rotation and the lower side is reverse direction rotation, and the arrows indicate forward torque and downward direction indicates reverse torque.

  While the vehicle is stopped, neither the front wheel drive device 6 nor the rear wheel drive device 1 is driven. Therefore, as shown in FIG. 5, the first and second electric motors 2A, 2B of the rear wheel drive device 1 are stopped, and the axles 10A, 10B are also stopped. Therefore, torque acts on any of the elements. Not. At this time, the hydraulic brakes 60A and 60B are released (OFF). The one-way clutch 50 is not engaged because the first and second electric motors 2A and 2B are not driven (OFF).

  Then, after the key position is turned ON, the rear wheel drive device 1 performs the rear wheel drive at the forward low vehicle speed with good motor efficiency such as EV start and EV cruise. As shown in FIG. 6, when the first and second electric motors 2A and 2B are power-driven so as to rotate in the forward direction, forward torque is applied to the sun gears 21A and 21B. At this time, as described above, the one-way clutch 50 is engaged and the ring gears 24A and 24B are locked. As a result, the planetary carriers 23A and 23B rotate in the forward direction and travel forward. In addition, traveling resistance from the axles 10A and 10B acts on the planetary carriers 23A and 23B in the reverse direction. As described above, when the vehicle 3 is started, the key position is turned ON to increase the torque of the first and second electric motors 2A and 2B, whereby the one-way clutch 50 is mechanically engaged and the ring gears 24A and 24B are locked. The

  At this time, the hydraulic brakes 60A and 60B are controlled to be in a weakly engaged state. The weak engagement means a state in which power can be transmitted but is fastened with a weak fastening force with respect to the fastening force of the hydraulic brakes 60A and 60B. When the forward torque of the first and second electric motors 2A and 2B is input to the rear wheel Wr, the one-way clutch 50 is engaged and power can be transmitted only by the one-way clutch 50. The hydraulic brakes 60A and 60B provided in parallel with the motor 50 are also weakly engaged and the first and second motors 2A and 2B and the rear wheel Wr are connected to each other, so that the first and second motors 2A and 2B are connected. Even when the forward torque input from the side temporarily decreases and the one-way clutch 50 enters the disengaged state, the first and second electric motors 2A, 2B and the rear wheel Wr are powered. It is possible to suppress the transmission failure. Further, it is not necessary to control the number of revolutions for connecting the first and second electric motors 2A, 2B and the rear wheel Wr when shifting to deceleration regeneration, which will be described later. By making the fastening force of the hydraulic brakes 60A, 60B when the one-way clutch 50 is engaged smaller than the fastening force of the hydraulic brakes 60A, 60B when the one-way clutch 50 is not engaged, the hydraulic brake 60A , Energy consumption for fastening 60B is reduced. In the following description, the one-way clutch 50 is engaged or the hydraulic brakes 60A and 60B are engaged, so that free rotation of the ring gears 24A and 24B is restricted (hereinafter, This is referred to as a ring lock state.) Drive control of the first and second electric motors 2A and 2B in a state where the first and second electric motors 2A and 2B and the rear wheel Wr side are connected and can transmit power. Also called lock control.

  When the vehicle speed increases from the forward low vehicle speed travel to the forward vehicle speed travel with good engine efficiency, the rear wheel drive by the rear wheel drive device 1 changes to the front wheel drive by the front wheel drive device 6. As shown in FIG. 7, when the power running drive of the first and second electric motors 2A, 2B is stopped, forward torque to travel forward from the axles 10A, 10B acts on the planetary carriers 23A, 23B. As described above, the one-way clutch 50 is disengaged. Also at this time, the hydraulic brakes 60A and 60B are controlled to a weakly engaged state.

  When the first and second electric motors 2A, 2B are to be regeneratively driven from the state of FIG. 6 or FIG. 7, as shown in FIG. 8, the planetary carriers 23A, 23B are in the order of continuing forward travel from the axles 10A, 10B. Since the direction torque acts, the one-way clutch 50 is disengaged as described above. At this time, the hydraulic brakes 60A and 60B are controlled to the engaged state (ON). Accordingly, the ring gears 24A and 24B are locked and the regenerative braking torque in the reverse direction is applied to the first and second electric motors 2A and 2B, and the first and second electric motors 2A and 2B are decelerated and regenerated. Thus, when the forward torque on the rear wheel Wr side is input to the first and second electric motors 2A, 2B, the one-way clutch 50 is disengaged, and power cannot be transmitted only by the one-way clutch 50. There is a state in which power can be transmitted by fastening hydraulic brakes 60A, 60B provided in parallel with the one-way clutch 50 and connecting the first and second motors 2A, 2B and the rear wheel Wr side. In this state, the energy of the vehicle 3 can be regenerated by controlling the first and second electric motors 2A and 2B to the regenerative drive state.

  Subsequently, at the time of acceleration, the four-wheel drive of the front wheel drive device 6 and the rear wheel drive device 1 is performed, and the rear wheel drive device 1 is in the same state as at the forward low vehicle speed shown in FIG.

  At the forward high vehicle speed, the front wheel drive device 6 performs front wheel drive. At this time, the first and second electric motors 2A and 2B are stopped and the hydraulic brakes 60A and 60B are controlled to be in a released state. The one-way clutch 50 is disengaged because the forward torque on the rear wheel Wr side is input to the first and second electric motors 2A, 2B, and the hydraulic brakes 60A, 60B are controlled to be released. The ring gears 24A and 24B start to rotate.

  As shown in FIG. 9, when the first and second electric motors 2A, 2B stop the power running drive, the forward torque to travel forward from the axles 10A, 10B acts on the planetary carriers 23A, 23B. As described above, the one-way clutch 50 is disengaged. At this time, the rotation loss of the sun gears 21A, 21B and the first and second electric motors 2A, 2B is input as resistance to the sun gears 21A, 21B, and the rotation loss of the ring gears 24A, 24B occurs in the ring gears 24A, 24B.

  By controlling the hydraulic brakes 60A and 60B to the released state, the ring gears 24A and 24B are allowed to freely rotate, and the first and second electric motors 2A and 2B and the rear wheel Wr are shut off to transmit power. It becomes impossible. Accordingly, the accompanying rotation of the first and second electric motors 2A and 2B is prevented, and the first and second electric motors 2A and 2B are prevented from over-rotating at a high vehicle speed by the front wheel drive device 6. In the above, the first and second electric motors 2A and 2B are stopped in the ring-free state. However, the first and second electric motors 2A and 2B may be driven in the ring-free state. The ring free control will be described later.

  During reverse travel, as shown in FIG. 10, when the first and second electric motors 2A, 2B are driven in reverse power running, reverse torque is applied to the sun gears 21A, 21B. At this time, as described above, the one-way clutch 50 is disengaged.

  At this time, the hydraulic brakes 60A and 60B are controlled to the engaged state (ON). Accordingly, the ring gears 24A and 24B are locked, and the planetary carriers 23A and 23B rotate in the reverse direction to travel backward. Note that traveling resistance from the axles 10A and 10B acts in the forward direction on the planetary carriers 23A and 23B. Thus, when the reverse torque on the first and second electric motors 2A, 2B side is input to the rear wheel Wr, the one-way clutch 50 is disengaged, and power transmission is impossible only by the one-way clutch 50. However, the hydraulic brakes 60A and 60B provided in parallel with the one-way clutch 50 are fastened, and the first and second electric motors 2A and 2B and the rear wheel Wr are kept in a connected state so that power can be transmitted. The vehicle 3 can be moved backward by the torque of the first and second electric motors 2A and 2B.

  Thus, the rear wheel drive device 1 is configured so that the traveling state of the vehicle, in other words, whether the rotation direction of the first and second motors 2A, 2B is the forward direction or the reverse direction, and the first and second motors 2A, 2B side. Engagement / release of the hydraulic brakes 60A and 60B is controlled according to which power is input from the rear wheel Wr side, and the engagement force is adjusted even when the hydraulic brakes 60A and 60B are engaged.

  FIG. 11 shows an electric oil pump when EV starts, EV acceleration, ENG acceleration, deceleration regeneration, medium-speed ENG cruise, ENG + EV acceleration, high-speed ENG cruise, deceleration regeneration, stop, reverse, and stop when the vehicle is stopped. 70 (EOP), one-way clutch 50 (OWC), hydraulic brakes 60A, 60B (BRK).

  First, the one-way clutch 50 is disengaged (OFF) and the hydraulic brakes 60A and 60B are released (OFF) until the key position is turned ON and the shift is changed from the P range to the D range and the accelerator pedal is depressed. To maintain. From there, when the accelerator pedal is stepped on, EV start and EV acceleration are performed by the rear wheel drive device 1 by rear wheel drive (RWD). At this time, the one-way clutch 50 is engaged (ON), and the hydraulic brakes 60A and 60B are in a weakly engaged state. When the vehicle speed changes from the low vehicle speed range to the medium vehicle speed range and changes from the rear wheel drive to the front wheel drive, ENG traveling (FWD) is performed by the internal combustion engine 4. At this time, the one-way clutch 50 is disengaged (OFF), and the hydraulic brakes 60A and 60B are maintained as they are (weakly engaged state). During deceleration regeneration such as when the brake is stepped on, the hydraulic brakes 60A and 60B are engaged (ON) while the one-way clutch 50 remains disengaged (OFF). During a medium speed cruise by the internal combustion engine 4, the state is the same as the above-described ENG traveling. Subsequently, when the accelerator pedal is further depressed to change from front wheel drive to four wheel drive (AWD), the one-way clutch 50 is engaged (ON) again. When the vehicle speed reaches from the middle vehicle speed range to the high vehicle speed range, the ENG traveling (FWD) by the internal combustion engine 4 is performed again. At this time, the one-way clutch 50 is disengaged (OFF), the hydraulic brakes 60A, 60B are disengaged (OFF), and the first and second motors 2A, 2B are not requested to drive, the first and first 2 The motors 2A and 2B are stopped, and when there is a drive request, ring-free control described later is performed. And at the time of deceleration regeneration, it will be in the state similar to the time of the deceleration regeneration mentioned above. When the vehicle stops, the one-way clutch 50 is disengaged (OFF) and the hydraulic brakes 60A and 60B are released (OFF).

  Subsequently, during reverse travel, the one-way clutch 50 remains disengaged (OFF) and the hydraulic brakes 60A and 60B are engaged (ON). When the vehicle stops, the one-way clutch 50 is disengaged (OFF) and the hydraulic brakes 60A and 60B are released (OFF).

Next, ring free control will be described.
In the ring-free control, the first and second electric motors are in a state where the one-way clutch 50 is disengaged and the hydraulic brakes 60A and 60B are disengaged, in other words, free rotation of the connected ring gears 24A and 24B is allowed. 2A and 2B drive control, in order to generate a target yaw moment (target left-right differential torque), the first and second motors 2A and 2B generate target torque (target torque control), the first and / or The second motors 2A and 2B can be controlled to the target rotational speed (target rotational speed control).

<Target torque control>
In the ring-free state, as described above, the first and second electric motors 2A, 2B and the rear wheel Wr are cut off and cannot transmit power. And the second motor 2B is controlled so that the absolute value of the second motor 2B is equal to that of the first motor 2A in the opposite direction (reverse direction or forward direction). It is possible to generate the desired yaw moment by generating a left-right differential torque between the left rear wheel LWr and the right rear wheel RWr without causing a rotational speed fluctuation in 2B.

  For example, a case where a clockwise yaw moment M is generated in the vehicle 3 will be specifically described with reference to FIG. By performing torque control so that the first motor base torque TM1 in the forward direction is generated in the first motor 2A, the first motor base torque TM1 in the forward direction acts on the sun gear 21A. At this time, as in FIG. 9, forward torque (not shown) acting to travel forward from the axle 10 </ b> A is acting on the planetary carrier 23 </ b> A. Accordingly, in the first planetary gear type speed reducer 12A, the planetary carrier 23A serves as a fulcrum, and the forward first motor base torque TM1 acts on the sun gear 21A, which is the power point, so that it acts on the ring gears 24A, 24B, which are the action points. The first motor base torque distribution force TM1 'in the reverse direction acts. Note that in FIG. 12 and the subsequent figures, the vector due to the loss or the like that is constantly applied to each rotating element is also omitted.

  On the other hand, by performing torque control so that the second motor base torque TM2 in the reverse direction is generated in the second electric motor 2B, the second motor base torque TM2 in the reverse direction acts on the sun gear 21B. At this time, as in FIG. 9, forward torque (not shown) acting to travel forward from the axle 10 </ b> B acts on the planetary carrier 23 </ b> B. Therefore, in the second planetary gear type speed reducer 12B, the planetary carrier 23B serves as a fulcrum, and the second motor base torque TM2 in the reverse direction acts on the sun gear 21B, which is the power point, so that it acts on the ring gears 24A, 24B, which are the action points. The forward second motor base torque distributing force TM2 'acts.

  Here, since the first motor base torque TM1 and the second motor base torque TM2 are torques in the opposite directions having the same absolute value, the first motor base torque distributing force TM1 ′ acting in the reverse direction acting on the ring gears 24A and 24B and the forward direction. The second motor base torque distribution force TM2 'cancels each other (offset). Accordingly, the first motor base torque TM1 and the second motor base torque TM2 do not contribute to the rotation fluctuation, and the sun gears 21A and 21B and the ring gears 24A and 24B are maintained in their respective rotation states. At this time, the forward left rear wheel torque TT1 obtained by multiplying the first motor base torque TM1 by the reduction ratio of the first planetary gear type speed reducer 12A acts on the planetary carrier 23A, and the planetary carrier 23B has The right rear wheel torque TT2 in the reverse direction acts by multiplying the second motor base torque TM2 by the reduction ratio of the second planetary gear type reduction gear 12B.

  Since the reduction ratios of the first and second planetary gear type speed reducers 12A and 12B are equal, the left and right rear wheel torques TT1 and TT2 become torques in opposite directions having the same absolute value, and thereby the difference between the left and right rear wheel torques TT1 and TT2 ( A clockwise yaw moment M corresponding to TT1-TT2) is stably generated.

  The target motor base torque when the target torque control is performed on the first and second electric motors 2 </ b> A and 2 </ b> B is obtained based on the target yaw moment of the vehicle 3. A method of obtaining the target motor base torque will be described using the following formula.

  The left rear wheel target torque of the left rear wheel LWr is WTT1, the right rear wheel target torque of the right rear wheel RWr is WTT2, and the total target torque of the left and right rear wheels LWr and RWr (the sum of the left rear wheel torque and the right rear wheel torque) Where TTT is the target torque difference between the left and right rear wheels LWr and RWr (the difference between the left rear wheel torque and the right rear wheel torque) is ΔTT, the following equations (1) and (2) are established.

WTT1 + WTT2 = TRT (1)
WTT1-WTT2 = ΔTT (2)

ΔTT is expressed by the following equation (3), where YMT is the target yaw moment (clockwise is positive), r is the wheel radius, and Tr is the tread width (distance between the left and right rear wheels LWr and RWr).
ΔTT = 2 · r · YMT / Tr (3)

Here, in the ring-free state, torque in the same direction by the first and second electric motors 2A and 2B is not transmitted to the rear wheel Wr, so the total target torque TRT of the left and right rear wheels LWr and RWr is zero. Accordingly, the target torques WTT1 and WTT2 for the left and right rear wheels LWr and RWr are uniquely determined from the above equations (1) and (2).
That is, WWT1 = −WTT2 = ΔTT / 2 (4)

  When the target motor base torque of the first electric motor 2A connected to the left rear wheel LWr is TTM1, and the target motor base torque of the second electric motor 2B connected to the right rear wheel RWr is TTM2, The target motor base torques TTM1, TTM2 of the second electric motors 2A, 2B are derived from the following equations (5), (6).

TTM1 = (1 / Ratio) · WTT1 (5)
TTM2 = (1 / Ratio) · WTT2 (6)
Ratio is the reduction ratio of the first and second planetary gear type speed reducers 12A and 12B.

From the above formulas (4) to (6), the target motor base torques TTM1, TTM2 of the left and right first and second electric motors 2A, 2B are expressed by the following formulas (7), (8).
TTM1 = (1 / Ratio) · ΔTT / 2 (7)
TTM2 = − (1 / Ratio) · ΔTT / 2 (8)
Therefore, the target torque difference ΔTT between the left and right rear wheels LWr, RWr is obtained based on the target yaw moment YMT of the vehicle 3, and half the target torque difference ΔTT is divided by the reduction ratio of the first planetary gear type speed reducer 12A. By setting the values to the target motor base torques TTM1 and TTM2 of the first and second electric motors 2A and 2B for target torque control, the desired yaw moment can be generated.

<Target speed control>
In the ring-free state, that is, when the one-way clutch 50 is disengaged and the hydraulic brakes 60A and 60B are disengaged, the connected ring gear even if torque is generated in the same direction from the first and second electric motors 2A and 2B Since 24A and 24B are not locked and the above-described cancellation of the motor torque distribution force does not occur, torque is not transmitted to the rear wheel Wr, and the sun gears 21A and 21B (first and second electric motors 2A and 2B) Only the rotational speed fluctuations of the ring gears 24A and 24B occur.

  In this case, the first and / or second electric motors 2A and 2B generate the rotation control torque in the same direction having the same absolute value so that the rotation control torque is not transmitted to the rear wheel Wr and the first and / or second electric motors 2A. 2B can be controlled to an intended rotational speed.

  For example, the case where the rotation speeds of the first and second electric motors 2A and 2B are lowered is described as an example with reference to FIG. By performing torque control so that the first rotation control torque SM1 in the reverse direction is generated in the first motor 2A, the first rotation control torque SM1 in the reverse direction acts on the sun gear 21A. At this time, as in FIG. 9, forward torque (not shown) acting to travel forward from the axle 10 </ b> A is acting on the planetary carrier 23 </ b> A. Accordingly, in the first planetary gear type speed reducer 12A, the planetary carrier 23A serves as a fulcrum, and the first rotation control torque SM1 in the reverse direction acts on the sun gear 21A that is the power point, so that it acts on the ring gears 24A and 24B that are the action points. The first rotation control torque distribution force SM1 ′ in the forward direction acts.

  Similarly, by performing torque control so that the second rotation control torque SM2 in the reverse direction is generated in the second electric motor 2B, the second rotation control torque SM2 in the reverse direction acts on the sun gear 21B. At this time, as in FIG. 9, forward torque (not shown) acting to travel forward from the axle 10 </ b> B acts on the planetary carrier 23 </ b> B. Therefore, in the second planetary gear type speed reducer 12B, the planetary carrier 23B serves as a fulcrum, and the second rotation control torque SM2 in the reverse direction acts on the sun gear 21B that is the power point, so that it acts on the ring gears 24A and 24B that are the action points. The second rotation control torque distribution force SM2 ′ in the forward direction acts.

  Here, since the first and second rotation control torques SM1 and SM2 are torques in the same direction having the same absolute value, the first and second rotation control torque distribution forces SM1 ′ and SM2 ′ acting on the ring gears 24A and 24B are also absolute. The torques in the same direction have the same value, and the first and second rotation control torque distribution forces SM1 ′ and SM2 ′ act in the direction of increasing the rotation speed of the ring gears 24A and 24B. At this time, since the first and second planetary gear type speed reducers 12A and 12B do not have a torque balanced with the first and second rotation control torques SM1 and SM2, the planetary carriers 23A and 23B include the first and first planetary gear speed reducers 12A and 12B. The left and right rear wheel torque is not generated by the two-rotation control torques SM1 and SM2. Therefore, the first and second rotation control torques SM1 and SM2 contribute only to the rotation fluctuation, reduce the rotation speeds of the first and second electric motors 2A and 2B and the rotation speeds of the sun gears 21A and 21B, and increase the first and second rotation torques SM1 and SM2. The two-rotation control torque distribution forces SM1 ′ and SM2 ′ increase the rotation speed of the ring gears 24A and 24B. Thus, by appropriately generating the first and second rotation control torques SM1 and SM2, the first and second electric motors 2A and 2B can be controlled to arbitrary target rotational speeds, and the first and second electric motors are eventually added. 2A and 2B are motor target rotational speeds.

  Since the rear wheel drive device 1 is connected to the ring gears 24A and 24B, the rear wheel drive device 1 cannot be controlled to satisfy the motor target speed of the first electric motor 2A and the motor target speed of the second electric motor 2B at the same time. In this case, the target rotational speed of one of the motors is controlled so as to satisfy the motor target rotational speed of either one of the motors.

<Target torque control + target rotation speed control>
12 (a) and 12 (b) show the target torque control for generating the target torque in the first and second electric motors 2A and 2B in order to generate the target yaw moment in the ring-free state, and the first and / or the first Although the target rotational speed control for controlling the two motors 2A and 2B to the target rotational speed is separately described, the first and / or the second while generating the desired yaw moment by performing this simultaneously. The electric motors 2A and 2B can be controlled to an intended rotational speed.

  FIG. 13 shows the first and second motor base torques TM1 and TM2 shown in FIG. 12 (a) and the first and second motor base torque distribution forces TM1 ′ and TM2 ′ as their distribution forces, and FIG. 12 (b). The first and second rotation control torques SM1 and SM2 and the first and second rotation control torque distribution forces SM1 ′ and SM2 ′ that are distribution forces thereof are described together.

  In this case, the first motor 2A actually generates a first motor torque M1 in the forward direction (first motor base torque TM1 + first rotation control torque SM1), and in the reverse direction from the second motor 2B. The second motor torque M2 (second motor base torque TM2 + second rotation control torque SM2) is generated, whereby the forward left rear wheel torque TT1 acts on the planetary carrier 23A, and the planetary The right rear wheel torque TT2 in the reverse direction acts on the carrier 23B, and a clockwise yaw moment M is generated. At the same time, the rotation speeds of the first and second electric motors 2A and 2B and the rotation speeds of the sun gears 21A and 21B are decreased, and the rotation speeds of the ring gears 24A and 24B are increased. Eventually, the first and second electric motors 2A and 2B are increased. Becomes the target motor speed.

  Next, switching between ring lock control and ring free control, which is a feature of the present invention, will be described with reference to FIGS.

  FIG. 14A shows the first planetary gear type speed reducer when the vehicle 3 is turning left in the middle vehicle speed range (during forward vehicle speed), that is, according to the rotational speed difference between the left rear wheel LWr and the right rear wheel RWr. The rotational speed of the sun gear 21B and the planetary carrier 23B of the second planetary gear speed reducer 12B is larger than that of the 12A sun gear 21A and the planetary carrier 23A, and the rear wheel drive device 1 assists the turning of the vehicle 3, A first motor base torque TM1 in the reverse direction is generated from the first motor 2A, and a second motor base torque TM2 in the opposite direction (forward direction) having the same absolute value as the first motor base torque TM1 is generated from the second motor 2B. This shows a state in which the counterclockwise yaw moment M is generated.

  In this state, when the vehicle speed exceeds the threshold and reaches a high vehicle speed range, a release command for the hydraulic brakes 60A and 60B is input. When the hydraulic brakes 60A, 60B are released, the sun gears 21A, 21B (S) and the ring gears 24A, 24B (R) other than the planetary carriers 23A, 23B (C) connected to the left rear wheel LWr and the right rear wheel RWr. Can be set to any number of revolutions. For example, as shown in FIG. 14B, in order to rotate the first electric motor 2A rotating at the rotational speed MA1 at the efficient rotational speed MA2, the rotational speed MA2 is set to the motor target rotational speed of the first electric motor 2A. To release the hydraulic brakes 60A and 60B. Further, the first electric motor 2A further generates the first rotation control torque SM1 in the reverse direction corresponding to the difference between the motor actual rotation speed MA1 and the motor target rotation speed MA2, and the second electric motor 2B further includes the first rotation control torque SM1. A second rotation control torque SM2 in the same direction (reverse direction) having the same absolute value as the rotation control torque SM1 is generated.

  At this time, the first motor torque M1 (first motor base torque TM1 + first rotation control torque SM1) is actually generated from the first electric motor 2A, and the second motor torque M2 (first motor control torque SM1) is generated from the second electric motor 2B. That is, second motor base torque TM2 + second rotation control torque SM2) is generated. Then, when the actual motor rotation speed MA1 of the first electric motor 2A reaches the motor target rotation speed MA2, as shown in FIG. 14C, the first and second rotation control torques SM1 and SM2 are extinguished. At this time, the rotational speed of the second electric motor 2B and the rotational speed of the sun gear 21B are uniquely determined by the rotational speed of the planetary carrier 23B connected to the right rear wheel RWr and the rotational speeds of the ring gears 24A and 24B.

  As described above, even in the ring-free state, the first and second motors 2A and 2B are generated while generating the desired yaw moment by applying the rotation control torque in the same direction having the same absolute value to both the motors. Can be prevented from over-rotating.

  By the way, in the ring lock state, the ring gears 24A and 24B are fixed, and accordingly, when the rotational speed of the planetary carriers 23A and 23B connected to the left and right rear wheels LWr and RWr increases according to the vehicle speed, the sun gears 21A and 21B The rotational speeds of the first and second electric motors 2A and 2B connected to the sun gears 21A and 21B also increase. The electric motor has the property that the motor torque that can be output decreases as the motor speed increases. Accordingly, in the ring lock state, since the motor rotation speed is proportional to the vehicle speed, the motor torque that can be output by the first and second electric motors 2A and 2B decreases as the vehicle speed increases as shown in FIG. Resulting in.

  On the other hand, in the ring-free state, the ring gears 24A and 24B are allowed to freely rotate, so that the rotational speeds of the planetary carriers 23A and 23B connected to the left and right rear wheels LWr and RWr increase according to the vehicle speed. In addition, the rotational speeds of the first and second electric motors 2A and 2B connected to the sun gears 21A and 21B and the sun gears 21A and 21B can be freely set regardless of the rotational speeds of the planetary carriers 23A and 23B. Therefore, in the ring-free state, the motor rotation speed is not proportional to the vehicle speed, and the motor torque that can be output by the first and second electric motors 2A and 2B, as shown in FIG. It becomes possible to freely set the upper limit torque (MOT upper limit torque) of the motor determined by the motor specifications as a limit.

  Therefore, as shown in FIG. 16, for example, when the control system 100 switches from the ring lock state to the ring free state, the ring free limit torque (the limit torque of the first and second electric motors 2A and 2B after switching) RF limit torque) is set to a value having an absolute value larger than the upper limit torque (MOT upper limit torque) of the first and second electric motors 2A and 2B determined by the electric motor specifications in the ring lock state at the time of switching. Control is performed so that the torque generated by the second electric motors 2A and 2B is less than the ring-free limit torque (RF limit torque).

  16 and FIGS. 17 to 20, the upper limit torque (MOT upper limit torque) determined by the motor specifications may be a short-time rated drive torque applied when the vehicle 3 starts, etc. In consideration of the continuous rated drive torque, the absolute value may be smaller than the short-time rated drive torque. Here, the ring-free limiting torque (RF limiting torque) can be freely set up to the upper limit torque (MOT upper limit torque) of the motor determined by the motor specifications, but a large torque is suddenly output at high vehicle speeds. The vehicle behavior may be disturbed, and is preferably set to a value smaller than the upper limit torque (MOT upper limit torque) of the electric motor. Even when the ring-free limit torque (RF limit torque) is set to a value smaller than the upper limit torque (MOT upper limit torque) of the motor as described above, if a control failure occurs, the upper limit of the motor There is a risk that an unintended large torque will occur with the torque (MOT upper limit torque) as a limit, and if a large torque is suddenly output at a high vehicle speed, the vehicle behavior may be disturbed. A control system according to an embodiment of the present invention that avoids this will be described below.

FIG. 21 is a configuration diagram of a control system according to an embodiment of the present invention. In the control system 100 shown in FIG. 21, for the sake of simplicity, only the configuration directly related to the control of the present invention is shown, and the configuration for controlling the internal combustion engine 4 and the electric motor 5 of the front wheel drive device 6 is omitted. ing.
In the control system 100, a first PDU (power drive unit) 80a is connected to the first motor 2A that drives the left rear wheel LWr, and a second PDU (power) is connected to the second motor 2B that drives the right rear wheel RWr. Drive unit) 80b is connected to each of the high-voltage batteries 9.

  Although not shown, each of the first and second PDUs 80a and 80b includes a bridge circuit in which switching elements are bridge-connected, and includes a PWM inverter driven by pulse width modulation (PWM). The first and second PDUs 80a and 80b convert the DC power output from the battery 9 into three-phase AC power and supply it to the first and second motors 2A and 2B when the first and second motors 2A and 2B are driven. When the first and second motors 2A and 2B are regenerated, the three-phase AC power output from the first and second motors 2A and 2B is converted into DC power to charge the battery 9.

  An electric motor ECU (electronic control unit) 81a is connected to the first and second PDUs 80a and 80b. The electric motor ECU 81a includes a ring gear rotation state acquisition unit 91, a second RF limit torque acquisition unit 92, and a second limit unit 93. The control system 100 is provided with a main ECU (electronic control unit) 81b separately from the electric motor ECU 81a. The main ECU (electronic control unit) 81b includes a BRK state switching unit 94, a ring gear rotation state acquisition unit 95, a first RF limit torque acquisition unit 96, and a first limit unit 97.

  The BRK state switching unit 94 and the ring gear rotation state acquisition unit 95 of the main ECU 81b are input with the rotation speed sensor detection value detected by the rotation speed sensor 85 of the transmission 7 of the front wheel drive device 6. The BRK state switching unit 94 acquires the vehicle speed from the input rotation speed sensor detection value of the transmission 7, and switches between the engaged state and the released state of the hydraulic brakes 60A and 60B according to the vehicle speed. As described above, when the vehicle speed exceeds the predetermined threshold and reaches the high vehicle speed range, the BRK state switching unit 94 outputs an OFF signal to a solenoid valve provided in a hydraulic circuit (not shown) for releasing the hydraulic brakes 60A and 60B. Is output. By releasing the hydraulic brakes 60A and 60B, the ring gears 24A and 24B are allowed to freely rotate, and the ring is free. In this specification, “acquisition” is a concept including estimation, calculation, and detection.

  The ring gear rotation state acquisition unit 95 acquires the vehicle speed from the rotation sensor detection value of the transmission 7 and acquires the ring free state. The ring gear rotation state acquisition unit 95 may acquire the ring free state from the BRK state switching unit 94. The BRK state switching unit 94 and the ring gear rotation state acquisition unit 95 replace the rotation speed of the transmission 7 of the front wheel drive device 6 with a value related to the rotation state amount of the first electric motor 2A that is correlated with the vehicle speed (for example, detection of the resolver 20A). Value, the number of revolutions of the sun gear 21A, etc.), a value related to the rotational state amount of the second electric motor 2B (for example, the detected value of the resolver 20B, the number of revolutions of the sun gear 21B, etc.) may be used. Rotation state quantity related values (for example, the wheel speed of the left rear wheel LWr, the rotational speed of the planetary carrier 23A, etc.) may be used, and the rotation state quantity related values of the right rear wheel RWr (for example, the wheel of the right rear wheel RWr) Speed, the number of revolutions of the planetary carrier 23B, etc.), a value related to the rotational state amount of the front wheel Wf (for example, a detected value of the wheel speed sensor), or the vehicle speed may be used directly.

  The wheel speed sensor detection value detected by the wheel speed sensor 83 of the rear wheel Wr is input to the ring gear rotation state acquisition unit 91 of the electric motor ECU 81a. The ring gear rotation state acquisition unit 91 acquires the vehicle speed from the input wheel speed sensor detection value, and acquires the ring free state. The ring gear rotation state acquisition unit 91 obtains the rotation state quantity related value (for example, the detection value of the resolver 20A, the rotation speed of the sun gear 21A, etc.) of the first electric motor 2A correlated with the vehicle speed instead of the wheel speed of the rear wheel Wr. The rotational state quantity related value of the second electric motor 2B (for example, the detected value of the resolver 20B, the rotational speed of the sun gear 21B, etc.) may be used, and the rotational state quantity related value of the left rear wheel LWr (for example, left The wheel speed of the rear wheel LWr, the rotational speed of the planetary carrier 23A, etc.) may be used, and the value related to the rotational state quantity of the right rear wheel RWr (for example, the wheel speed of the right rear wheel RWr, the rotational speed of the planetary carrier 23B, etc.) May be used, the rotational state quantity related value of the front wheel Wf (for example, the number of revolutions of the transmission 7 or the like) may be used, and the vehicle speed may be used directly. However, the vehicle speed correlation amount (in this embodiment, the wheel speed of the rear wheel Wr) input to the ring gear rotation state acquisition unit 95 of the main ECU 81b and the vehicle speed correlation amount input to the ring gear rotation state acquisition unit 91 of the electric motor ECU 81a ( In the present embodiment, it is preferable that the rotation speed of the transmission 7 is different. In general, since the mission rotational speed sensor is more reliable than the wheel speed sensor, the rotational speed of the transmission 7 is an information source input to the ring gear rotational state acquisition unit 95 of the main ECU 81b that performs various controls. preferable.

  When the ring gear rotation state acquisition units 95 and 91 acquire the ring free state, the first and second RF limit torque acquisition units 96 and 92 respectively acquire the first and second ring free limit torques based on the acquired vehicle speed. Can do. For example, the first and second ring-free limiting torques corresponding to the vehicle speed can be acquired from a map in which the vehicle speed and the ring-free limiting torque are associated with each other. If the ring-free limiting torque is shown in FIG. 16 and FIGS. 17 to 19 described later, one value is acquired. If the ring-free control is shown in FIG. 20 described later, one of the two values is selected according to the vehicle speed. One value is obtained.

  The first limiting unit 97 of the main ECU 81b causes the torques of the first and second electric motors 2A and 2B to be within the first ring-free limiting torque based on the first ring-free limiting torque acquired by the first RF limiting torque acquiring unit 96. Control as follows. Specifically, the first ring-free limiting torque is output to the second limiting unit 93 of the electric motor ECU 81a. The first limiting unit 97 is preferably configured to be able to communicate with the second limiting unit 93 (for example, CAN communication), and outputs the first ring-free limiting torque to the second limiting unit 93 by transmission. It is preferable.

  The second limiting unit 93 of the electric motor ECU 81a causes the torques of the first and second electric motors 2A and 2B to be within the second ring-free limiting torque based on the second ring-free limiting torque acquired by the second RF limiting torque acquiring unit 92. Control as follows. Specifically, the second ring free limit torque acquired by the second RF limit torque acquisition unit 92 is compared with the first ring free limit torque transmitted from the first limit unit 97, and both ring free limit torques are different. In this case, a control signal is output to the first and second PDUs 80a and 80b that drive the first and second electric motors 2A and 2B based on the smaller ring-free limiting torque. In addition, the 2nd limitation part 93 is set to the 2nd ring free limitation torque acquired in the 2nd RF limitation torque acquisition part 92, when the wheel speed sensor detection value input into the ring gear rotation state acquisition part 91 exceeds predetermined value. Based on this, control signals may be output to the first and second PDUs 80a and 80b that drive the first and second electric motors 2A and 2B.

  As described above, according to the present embodiment, the control system 100 controls the torques of the first and second electric motors 2A and 2B to be within the first ring-free limiting torque when acquiring the ring-free state. A first limiter 97 that is provided separately from the first limiter 97 and controls the torque of the first and second electric motors 2A and 2B to be within the second ring-free limit torque, Therefore, the torque limitation of the first and second electric motors 2A and 2B in the ring-free state is not limited structurally but depends on the control limitation. By making the torque limitation redundant, unnecessary motor torque Disturbances in vehicle behavior due to the occurrence of this can be reliably prevented.

  The first limiter 97 acquires the ring-free state by the rotation speed sensor 85 of the transmission 7 that acquires the vehicle speed correlation amount, and the second limiter 93 is provided separately from the rotation speed sensor 85 of the transmission 7. Since the ring-free state is acquired by the wheel speed sensor 83 of the rear wheel Wr that acquires the vehicle speed correlation amount, even if the rotation speed sensor 85 and the wheel speed sensor 83 are out of order, the vehicle is caused by generation of unnecessary motor torque. Disturbance of behavior can be reliably prevented. Further, since the vehicle speed correlation amounts are obtained from the related values of the rotational state amounts of the front wheels Wf and the rear wheels Wr, the redundancy is further improved. Redundancy can be improved by using the vehicle speed correlation amount that can be obtained in various ways.

  The second limiter 93 compares the second ring-free limit torque acquired by the second RF limit torque acquisition unit 92 with the first ring-free limit torque transmitted from the first limiter 97, and the first ring-free limit torque And the second ring free limit torque are different, the first and second electric motors 2A and 2B are controlled based on the smaller ring free limit torque, so even if a control failure occurs, it is small The motor torque can be generated within the ring free limit torque.

  Moreover, it is preferable that the 2nd restriction | limiting part 93 is installed in ECU arrange | positioned closest to the 1st and 2nd electric motors 2A and 2B in the signal flow direction on the circuit of the control system 100. The first and second electric motors 2A and 2B in this case are a concept including first and second PDUs 80a and 80b for driving the first and second electric motors 2A and 2B. As a result, even if an abnormality in the circuit itself or an abnormality in communication occurs upstream of the electric motor ECU 81a, the motor torque can be surely limited.

  Further, as shown in FIG. 17, in the ring lock state, the control system 100 sets the first and second electric motors to a value smaller in absolute value than the upper limit torque (MOT upper limit torque) of the first and second electric motors 2A and 2B. A ring lock limit torque (RL limit torque) that is a limit torque of 2A and 2B may be set. In this case, a ring-free limit torque (RF that is a limit torque of the first and second electric motors 2A and 2B after switching). Limit torque) is set to a value whose absolute value is larger than the ring lock limit torque (RL limit torque) at the time of switching, and the torque generated by the first and second electric motors 2A and 2B is the ring free limit torque (RF limit). Control to be less than (torque).

  Thus, in the ring-free state, there is no correlation between the rotational speeds of the first and second electric motors 2A, 2B and the left and right rear wheels LWr, RWr, while the left and right rear wheels LWr, RWr are in the opposite direction having the same absolute value. Taking advantage of the ability to transmit the motor torque, the vehicle operating stability can be improved by raising the limit torque after the hydraulic brakes 60A and 60B are released to be higher than the limit torque in the ring lock state.

  In the embodiment of FIGS. 16 and 17 described above, the ring-free limit torque (RF limit torque), which is the limit torque of the first and second electric motors 2A and 2B after switching, is set in the ring lock state at the time of switching. Although the absolute value is set larger than the upper limit torque (MOT upper limit torque) or ring lock limit torque (RL limit torque) of the first and second motors 2A and 2B, as shown in FIG. 18 and FIG. The ring-free limiting torque (RF limiting torque), which is the limiting torque of the first and second motors 2A, 2B, is set to the upper limit torque (MOT upper limit) of the first and second motors 2A, 2B in the ring-locked state at the time of switching. Torque) or ring lock limit torque (RL limit torque), and a torque generated by the first and second electric motors 2A and 2B. It may be controlled to less than the ring-free limit torque (RF limit torque).

  Thus, in the ring-free state, there is no correlation between the rotational speeds of the first and second electric motors 2A, 2B and the left and right rear wheels LWr, RWr, while the left and right rear wheels LWr, RWr are in the opposite direction having the same absolute value. Although the motor torque can be transmitted, the limit torque after the release of the hydraulic brakes 60A and 60B is set to a value substantially equal to the limit torque in the ring lock state, so that the torque at the time of transition from the ring lock state to the ring free state can be obtained. A sudden torque change can be suppressed.

  In addition, after the vehicle speed further increases after switching or after a predetermined time has elapsed, as shown in FIG. 20, the ring-free limit torque (RF limit torque) of the first and second motors 2A, 2B is determined by the motor specifications. You may change within the range of a torque (MOT upper limit torque). Thereby, even if the target yaw moment is changed, the vehicle maneuverability can be maintained. 16 to 20 describe the case where the first and second electric motors 2A and 2B are driven by power running, the same applies to the case of regenerative driving.

Moreover, the said embodiment of this invention also provides the following aspects.
In the control system 100 described above, the one-way clutch 50 is disengaged and the hydraulic brakes 60A and 60B are disengaged (ring-free state), that is, the first and second electric motors 2A and 2B and the rear wheel Wr. In the state in which power is not transmitted due to the shut-off state, the rotational speed detected by the wheel speed sensor detection value detected by the rotational speed sensor 85 of the transmission 7 of the front wheel drive device 6 and the wheel speed sensor 83 of the rear wheel Wr. The first and second ring-free limiting torques are acquired from the sensor detection values, and the torques of the first and second electric motors 2A and 2B are controlled to be within the ring-free limiting torque.

  Generally, in a state where the power transmission path between the motor and the wheel is cut off, the motor is controlled based on the rotational state amount on the motor side. However, in the above embodiment, the power transmission path between the motor and the wheel is cut off. In this state, the electric motor is controlled based only on the rotational state amount on the wheel side. As a result, the torque limit of the motor in a state in which power cannot be transmitted does not depend on the structural limit but depends on the control limit. Therefore, the torque limit can be made redundant, resulting in generation of unnecessary motor torque. Disturbance of vehicle behavior can be reliably prevented.

  In this control, one element of the first and second transmissions having the first to third rotating elements does not need to be connected to each other, and can be established without including the transmission itself.

In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.
For example, it is not necessary to provide the hydraulic brakes 60A and 60B on the ring gears 24A and 24B, respectively, it is sufficient that at least one hydraulic brake is provided on the connected ring gears 24A and 24B, and it is not always necessary to include a one-way clutch. There is no. In this case, by controlling the hydraulic brake from the released state to the engaged state, the ring lock state can be changed to the ring free state.
Moreover, although the hydraulic drive type wet multi-plate brake is illustrated as the rotation restricting means, the invention is not limited to this, and a mechanical drive type, an electromagnetic drive type, and the like can be arbitrarily selected.
Further, the first and second electric motors 2A and 2B are connected to the sun gears 21A and 21B, and the ring gears are connected to each other. However, the present invention is not limited to this, the sun gears are connected to each other, and the first and second electric motors are connected to the ring gear. May be.
Further, the front wheel drive device 6 may use the electric motor 5 as a sole drive source without using the internal combustion engine 4.
Further, the front wheel drive device 6 may be used as a rear wheel drive device, and the rear wheel drive device 1 may be used as a front wheel drive device.

DESCRIPTION OF SYMBOLS 1 Rear wheel drive device 2A 1st electric motor 2B 2nd electric motor 3 Vehicle (electric vehicle)
6 Front wheel drive (other drive)
12A First planetary gear type speed reducer (first transmission)
12B Second planetary gear type speed reducer (second transmission)
20A, 20B resolver (upstream rotation state acquisition means)
21A, 21B Sun gear (first rotating element)
23A, 23B Planetary carrier (second rotating element)
24A, 24B Ring gear (third rotating element)
50 One-way clutch (rotation restricting means)
60A, 60B Hydraulic brake (rotation restricting means)
81a Electric motor ECU
81b Main ECU
83 Wheel speed sensor (second vehicle speed acquisition means, downstream rotation state acquisition means)
85 Rotational speed sensor (first vehicle speed acquisition means, downstream rotation state acquisition means)
93 Second restriction unit (second restriction means)
94 BRK state switching unit (state switching means)
97 1st restriction part (1st restriction means)
100 Control system (control means)
LWr Left rear wheel (left wheel)
RWr Right rear wheel (right wheel)
Wf Front wheel (other wheel)

Claims (4)

A left wheel drive device having a first motor that drives the left wheel, a first transmission provided on a power transmission path between the first motor and the left wheel, and a second motor that drives the right wheel And a right wheel drive device having a second transmission provided on a power transmission path between the second motor and the right wheel, and control means for controlling the first motor and the second motor. , An electric vehicle comprising:
The first and second transmissions each have first to third rotating elements,
The first electric motor is connected to the first rotating element of the first transmission;
The second electric motor is connected to the first rotating element of the second transmission;
The left wheel is connected to the second rotating element of the first transmission;
The right wheel is connected to the second rotating element of the second transmission;
The third rotating element of the first transmission and the third rotating element of the second transmission are connected to each other;
The electric vehicle can be released and fastened, and further includes a rotation restricting means for restricting the rotation of the third rotating element by being fastened,
The control means has state switching means for switching the rotation restricting means to release and fastening,
The state switching means switches between release and fastening of the rotation restricting means based on a vehicle speed correlation amount correlated with the vehicle speed of the electric vehicle,
The control means includes
Third rotation element rotation state acquisition means for acquiring the rotation state of the third rotation element;
When the third rotation element rotation state acquisition unit acquires that the rotation restriction unit is released and the third rotation element is in a rotation free state, the torques of the first motor and the second motor are set to a predetermined value. First limiting means for controlling to be within the limiting torque;
Separately provided with said first limiting means, have a, a second limiting unit for controlling so that the torque of the first electric motor and said second electric motor falls within a predetermined limit torque,
The first limiting means acquires the rotation free state by first vehicle speed acquisition means for acquiring the vehicle speed correlation amount;
The electric vehicle according to claim 1, wherein the second restriction unit is provided separately from the first vehicle speed acquisition unit, and acquires the rotation free state by a second vehicle speed acquisition unit that acquires the vehicle speed correlation amount . When the left wheel and the right wheel are the left wheel and the right wheel of either the front wheel or the rear wheel of the electric vehicle, and the other of the front wheel and the rear wheel of the electric vehicle is the other wheel,
The electric vehicle includes another driving device that drives the other wheel,
The first vehicle speed acquisition means acquires the vehicle speed correlation amount based on a rotation state amount of the other drive device,
The electric vehicle according to claim 1 , wherein the second vehicle speed acquisition unit acquires the vehicle speed correlation amount based on a rotation state amount of the one wheel. It said second limiting means, motorized described in the circuit of the control means, to claim 1 or 2, characterized in that it is arranged close to each other in the signal flow direction in the most said first and said second electric motor vehicle. The second limiting means outputs control signals for the first and second motors,
The first limiting means can communicate with the second limiting means,
The second limiting unit compares the limiting torque acquired by the second limiting unit with the limiting torque transmitted from the first limiting unit, and limits the limiting torque of the first limiting unit and the limiting of the second limiting unit. The electric vehicle according to claim 1 or 2 , wherein when the torque is different, the first and second electric motors are controlled based on a smaller limit torque.

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