JP2017184442A - Driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving device that can reduce loss at the time of releasing connecting/disconnecting means.SOLUTION: A rear wheel driving device 1 comprises: first and second electric motors 2A and 2B; a wet multiplate-type hydraulic brake 60, provided on a power transmission route between the first and second electric motors 2A and 2B and rear wheels Wr, which is released or fastened so that the electric motors and wheels are disconnected or connected; and a control device 8 that controls switching of the hydraulic brake 60 between the disconnection and the connection, and controls the first and second electric motors 2A and 2B. The control device 8 has high velocity of oil and, when corotation is caused in the first and second electric motors 2A and 2B in a state where the hydraulic brake 60 is released, performs low rotation control of rotating the first and second electric motors 2A and 2B at a rotation state quantity less than a converged rotation state quantity that is a rotation state quantity at which the states of corotation of the first and second electric motors 2A and 2B are converged in the state where the hydraulic brake 60 is released.SELECTED DRAWING: Figure 12

Description

  The present invention relates to a drive device in which connection / disconnection means is provided on a power transmission path between an electric motor and a driven part.

  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. In addition, the connected ring gear is brought into an engaged state when braking means for braking the rotation of the ring gear by releasing or fastening the ring gear and when unidirectional rotational power on the motor side is input to the wheel side. When the rotational power in the other direction on the motor side is input to the wheel side, the wheel is disengaged, and when the rotational power in one direction on the wheel side is input to the motor side, the wheel is disengaged. And a one-way clutch that is engaged when rotational power in the other direction is input to the electric motor side.

  In this vehicle drive device, when rotational power in one direction on the motor side is input to the wheel side, the brake means is fastened so that the motor and the wheel are in a connected state, and the vehicle speed is increased with the motor and the wheel in a connected state. In order to prevent over-rotation of the electric motor when the vehicle speed exceeds a predetermined vehicle speed, it is described that the brake means that has been engaged is released. When the brake means is released, the loss of the electric motor is larger than the loss of the ring gear. Therefore, normally, the rotation speed of the electric motor decreases and the ring gear starts to rotate, eventually the motor stops and the ring gear continues to rotate.

JP 2012-214176 A

  By the way, in the vehicle drive device described in Patent Document 1, a part of the brake means is located in the oil storage part stored below the case. Therefore, when the viscosity of the oil is high, such as at low temperatures, the agitation resistance of the oil increases, and even if the brake means is released, the rotation speed of the motor does not fall below a predetermined value, and the motor may continue to rotate with a large loss. was there.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a drive device that can reduce the loss when the connecting / disconnecting means is released.

In order to achieve the above object, the invention described in claim 1
An electric motor (for example, first and second electric motors 2A and 2B of an embodiment to be described later) that generates a driving force of a vehicle (for example, a vehicle 3 of the embodiment to be described later);
An electric motor control device for controlling the electric motor (for example, a control device 8 of an embodiment described later);
A wet type which is provided on a power transmission path between the electric motor and a wheel of the vehicle (for example, a rear wheel Wr in an embodiment described later), and releases or fastens the electric motor side and the wheel side in a disconnected state or a connected state. A multi-plate type connecting / disconnecting means (for example, a hydraulic brake 60 according to an embodiment described later);
A drive device (for example, rear wheel drive of the embodiment described later) including a connection / disconnection means control device (for example, a control device 8 of the embodiment described later) that controls switching between the disconnected state and the connected state of the connection / disconnection device. Device 1),
The electric motor control device is a liquid fluid (for example, in the later-described embodiment) that is used for cooling a multi-plate portion (for example, a fixed plate 35 and a rotating plate 36 in the later-described embodiment) of the wet multi-plate type connecting / disconnecting means. The amount of rotation state in which the state of rotation of the motor converges when the connection / disconnection means is released when the connection / release means is released when the connection / release means is released. Low rotation control (for example, low rotation control in the embodiment described later) for rotating the electric motor with a rotation state amount smaller than the convergence rotation state amount is performed.

Moreover, in addition to the structure of Claim 1, the invention of Claim 2 is
The electric motor control device is configured such that when the liquid fluid is high in viscosity and the connecting / disconnecting means is released, the electric motor is accompanied by the converging rotation state amount in a state where the connecting / disconnecting means is released. Convergent rotation control for rotating the electric motor (for example, convergent rotation control in an embodiment described later) is performed.

Moreover, in addition to the structure of Claim 2, the invention of Claim 3 is
The electric motor control device sets the electric motor to a rotational state amount smaller than the convergent rotational state amount when the liquid fluid has a high viscosity and the motor is accompanied with the connection / disconnection means released. On the basis of the estimated power consumption obtained from the initial power for rotation and the rotation maintaining power for continuing to rotate the motor at the rotational state quantity, and the loss when the motor rotates at the convergent rotational state quantity. One of rotation control and convergent rotation control is selected.

Moreover, in addition to the structure described in claim 2, the invention described in claim 4
The motor control device performs the low rotation control when the vehicle speed or the vehicle speed related value is equal to or greater than a predetermined value, and performs the convergent rotation control when the vehicle speed or the vehicle speed related value is less than the predetermined value.

Moreover, in addition to the structure of any one of Claims 1-4, invention of Claim 5 is provided,
The convergent rotation state quantity is obtained based on the viscosity and the vehicle speed or a vehicle speed related value, and is stored in the storage unit.

  According to the first aspect of the present invention, when the liquid fluid has a high viscosity and the motor is accompanied with the connecting and disconnecting means being released, the electric motor is driven with the connecting and disconnecting means being released. If the motor continues to rotate with the convergence rotation state amount that is the rotation state amount that the state converges, the loss increases with the rotation of the motor, but by rotating the motor with a rotation state amount smaller than the convergence rotation state amount, The electric motor can be rotated at an efficient operating point, and loss can be reduced.

  According to the second aspect of the present invention, the electric motor can be rotated with zero torque by continuing to rotate the electric motor at the convergent rotation state quantity, and the initial power and the electric motor for setting the electric motor to a desired rotational speed can be obtained. Rotational maintenance power for continuing to rotate at a desired rotational speed can be made unnecessary.

  According to the third aspect of the present invention, the estimated consumption obtained from the initial power for setting the electric motor to a rotational state quantity smaller than the convergence rotational state quantity and the rotation maintaining power for continuing to rotate the motor at the rotational state quantity. By selecting either low rotation control or convergent rotation control based on the electric power and the loss when the electric motor rotates with the convergent rotation state quantity, the loss when the viscosity of the liquid fluid is high can be reduced. .

  According to the fourth aspect of the invention, when the vehicle speed or the vehicle speed related value is equal to or higher than the predetermined value, that is, when the amount of convergence rotation state of the motor is high, the low rotation control is performed, and the vehicle speed or the vehicle speed related value is less than the predetermined value. In this case, that is, when the amount of convergence rotation state of the electric motor is low, by performing the convergence rotation control, the control can be easily performed while reducing the loss when the viscosity of the liquid fluid is high.

  According to the fifth aspect of the invention, the control can be facilitated by storing in advance the amount of convergence rotation state of the electric motor.

1 is a block diagram showing a schematic configuration of a hybrid vehicle that is an embodiment of a vehicle on which a drive device according to the present invention can be mounted. 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 (low viscosity). It is a speed alignment chart of the rear-wheel drive device at the time of reverse drive. It is a speed alignment chart of the rear-wheel drive device in the convergence rotation control of brake release loss reduction control. It is a speed alignment chart of the rear-wheel drive device in the low rotation control of brake release loss reduction control.

First, an embodiment of a drive device according to the present invention will be described with reference to FIGS.
The drive device according to the present embodiment uses an electric motor as a drive source for driving an axle, and is used, for example, in a vehicle having a drive system as shown in FIG. In the following description, a case where the driving device is used for driving the rear wheels will be described as an example, but the driving device may be used for driving the front wheels.
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 8 denotes a control device 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. A case 11 of the rear wheel drive device 1 is formed in a substantially cylindrical shape as a whole, and includes therein first and second motors 2A and 2B for driving an axle and driving of the first and second motors 2A and 2B. First and second planetary gear speed reducers 12A and 12B that reduce the rotation are arranged coaxially with 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 are symmetrical in the vehicle width direction in the case 11. Has been placed.

  The rear wheel drive device 1 is provided with a breather device 40 that communicates the inside and outside of the case 11 so that the air inside the case 11 escapes to the outside through the breather chamber 41 so that the air does not become excessively high temperature and pressure. Configured as follows. The breather chamber 41 is disposed at the upper part in the vertical direction of the case 11, and includes an outer wall of the central case 11M, a first cylindrical wall 43 extending substantially horizontally in the central case 11M on the left side case 11A side, and a right side case. A second cylindrical wall 44 extending substantially horizontally on the 11B side, a left and right dividing wall 45 connecting the inner ends of the first and second cylindrical walls 43, 44, and a left side case 11A of the first cylindrical wall 43. A space formed by a baffle plate 47A attached so as to abut on the side tip, and a baffle plate 47B attached so as to abut on the right side case 11B side tip of the second cylindrical wall 44. The

  The first and second cylindrical walls 43, 44 and the left and right dividing walls 45 that form the lower surface of the breather chamber 41 are such that the first cylindrical wall 43 is positioned radially inward from the second cylindrical wall 44, and the left and right dividing walls 45 are A third cylinder that extends from the inner end of the second cylindrical wall 44 to the inner end of the first cylindrical wall 43 while being bent while reducing the diameter, and further extends radially inward and extends substantially horizontally. Reach wall 46. The third cylindrical wall 46 is located on the inner side of both outer end portions of the first cylindrical wall 43 and the second cylindrical wall 44 and substantially in the center thereof.

  In the central case 11M, baffle plates 47A and 47B are provided in the space between the first cylindrical wall 43 and the outer wall of the central case 11M or the space between the second cylindrical wall 44 and the outer wall of the central case 11M as the first planet. It is fixed so as to be separated from the gear type speed reducer 12A or the second planetary gear type speed reducer 12B.

  In addition, an external communication path 49 that connects the breather chamber 41 and the outside is connected to the central case 11M on the upper surface in the vertical direction of the breather chamber 41. The breather chamber side end portion 49a of the external communication passage 49 is arranged so as to be directed downward in the vertical direction. Accordingly, the oil is prevented from being discharged to the outside through the external communication passage 49.

  In the first and second electric motors 2A and 2B, stators 14A and 14B are fixed to side cases 11A and 11B, respectively, and annular rotors 15A and 15B are rotatably arranged on the inner peripheral sides of the stators 14A and 14B. Yes. 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 can be relatively rotated coaxially with the axles 10A and 10B. The side cases 11A and 11B are supported by end walls 17A and 17B and partition walls 18A and 18B via bearings 19A and 19B. Further, on the outer periphery of one end side of the cylindrical shafts 16A and 16B and on the end walls 17A and 17B, the rotational position information of the rotors 15A and 15B is sent to the controller of the first and second electric motors 2A and 2B (not shown). Resolvers 20A and 20B are provided for feedback. The first and second electric motors 2A and 2B including the stators 14A and 14B and the rotors 15A and 15B have the same radius, and the first and second electric motors 2A and 2B are arranged in mirror symmetry with each other. The axle 10A and the cylindrical shaft 16A pass through the first electric motor 2A and extend from both ends of the first electric motor 2A. The axle 10B and the cylindrical shaft 16B also penetrate the second electric motor 2B. , Extending from both ends of the second electric motor 2B.

  The first and second planetary gear speed reducers 12A and 12B include sun gears 21A and 21B, ring gears 24A and 24B, and a plurality of planetary gears 22A and 22B meshing with the sun gears 21A and 21B and the ring gears 24A and 24B. And planetary carriers 23A and 23B that support these planetary gears 22A and 22B. The driving forces of the first and second electric motors 2A and 2B are input from the sun gears 21A and 21B, and the reduced drive rotation is caused by the planetary carrier 23A. , 23B to be output to the axles 10A, 10B.

  The sun gears 21A and 21B are formed integrally with the cylindrical shafts 16A and 16B. The planetary gears 22A and 22B are double pinions having first pinions 26A and 26B having large diameters directly meshed with the sun gears 21A and 21B, and second pinions 27A and 27B having smaller diameters than the first pinions 26A and 26B. The first pinions 26A and 26B and the second pinions 27A and 27B are integrally formed in a state of being coaxial and offset in the axial direction. The planetary gears 22A and 22B are supported by the pinion shafts 32A and 32B of the planetary carriers 23A and 23B via needle bearings 31A and 31B, and the planetary carriers 23A and 23B have an axially inner end extending radially inward to the axle 10A. 10B and is supported by the partition walls 18A and 18B via bearings 33A and 33B.

  The ring gears 24A and 24B have gear portions 28A and 28B that are meshed with the second pinions 27A and 27B whose inner peripheral surfaces are small diameters, and small diameters that are smaller than the gear portions 28A and 28B and that are opposed to each other at an intermediate position of the case 11. Parts 29A, 29B, and connecting parts 30A, 30B for connecting the axially inner ends of the gear parts 28A, 28B and the axially outer ends of the small diameter parts 29A, 29B in the radial direction.

  The gear portions 28A and 28B face each other in the axial direction with a third cylindrical wall 46 formed at the inner diameter side end portion of the left and right dividing wall 45 of the central case 11M. The outer diameter surfaces of 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 connected to each other so as to rotate integrally with the inner race 51 of the one-way clutch 50. Configured.

  On the second planetary gear type speed reducer 12B side, between the second cylindrical wall 44 of the central case 11M constituting the case 11 and the gear portion 28B of the ring gear 24B, a hydraulic brake constituting braking means for the ring gear 24B 60 is arranged so as to overlap with the first pinion 26B in the radial direction and overlap with the second pinion 27B in the axial direction. The hydraulic brake 60 includes a plurality of fixed plates 35 that are spline-fitted to the inner peripheral surface of the second cylindrical wall 44 and a plurality of rotary plates 36 that are spline-fitted to the outer peripheral surface of the gear portion 28B of the ring gear 24B. These plates 35 and 36 are arranged to be fastened and released by an annular piston 37. The piston 37 is accommodated in an annular cylinder chamber formed between the left and right dividing walls 45 of the central case 11M and the third cylindrical wall 46, and is further provided with a receiving provided on the outer peripheral surface of the third cylindrical wall 46. The elastic member 39 supported by the seat 38 is constantly urged in a direction to release the fixed plate 35 and the rotating plate 36.

  More specifically, the working chamber S into which oil is directly introduced is defined between the left and right dividing walls 45 and the piston 37, and when the pressure of the oil introduced into the working chamber S exceeds the urging force of the elastic member 39, The piston 37 moves forward (to the right), and the fixed plate 35 and the rotating plate 36 are pressed against each other and fastened. When the urging force of the elastic member 39 exceeds the pressure of the oil introduced into the working chamber S, the piston 37 moves backward (leftward movement), and the fixed plate 35 and the rotating plate 36 are separated and released. . The hydraulic brake 60 is connected to an electric oil pump 70 (see FIG. 1).

  In the case of this hydraulic brake 60, the fixed plate 35 is supported by the second cylindrical wall 44 extending from the left and right dividing walls 45 of the central case 11M constituting the case 11, while the rotating plate 36 is supported by the gear portion 28B of the ring gear 24B. Therefore, when the plates 35 and 36 are pressed by the piston 37, a braking force is applied to the ring gear 24B by the frictional engagement between the plates 35 and 36, and is fixed. When the fastening by the piston 37 is released from this state, the ring gear 24B is allowed to rotate freely. As described above, since the ring gears 24A and 24B are connected to each other, the braking force is also applied to the ring gear 24A when the hydraulic brake 60 is fastened, and the ring gear 24A is fixed when the hydraulic brake 60 is released. Free rotation is allowed.

  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. The outer race 52 is positioned by the third cylindrical wall 46 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, in the one-way clutch 50, when the rotational power in the forward direction (the rotational 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. Is engaged, and the first and second electric motors 2A, 2B are in the non-engaged state when the reverse rotational power is input to the rear wheel Wr, and the forward rotational power is applied to the rear wheel Wr. Is disengaged when the first and second electric motors 2A and 2B are input, and the reverse rotational power on the rear wheel Wr side is input to the first and second electric motors 2A and 2B. Is engaged.

  As described above, in the rear wheel drive device 1 of the present embodiment, the one-way clutch 50 and the hydraulic brake 60 are provided in parallel on the power transmission path between the first and second electric motors 2A and 2B and the rear wheel Wr. . Note that an oil storage portion T for storing oil is formed below the case 11, and the oil surface height is such that the lower ends of the rotors 15A and 15B of the first and second electric motors 2A and 2B are not submerged. In FIG. 2, reference numeral H), and the lower portions of the fixed plate 35 and the rotating plate 36 are located in the oil reservoir T.

  Here, the control device 8 (see FIG. 1) is a control device for performing various controls of the entire vehicle. The control device 8 includes wheel speed sensor values, motor speeds of the first and second electric motors 2A and 2B. While the sensor value, steering angle, accelerator pedal opening AP, shift position, state of charge (SOC) in the battery 9, oil temperature, and the like are input, a signal for controlling the internal combustion engine 4 from the control device 8, A signal for controlling the second electric motors 2A and 2B, a control signal for controlling the electric oil pump 70, and the like are output.

  That is, the control device 8 is a connection / disconnection means control device that controls a function as an electric motor control device that controls the first and second electric motors 2A, 2B, and an engagement state and a release state of the hydraulic brake 60 as connection / disconnection means. It has at least the function as.

  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 motors 2A, 2B, OWC represents the one-way clutch 50, and BRK represents the hydraulic brake 60. 5 to 12 show speed nomographs in each state 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 first motor 2A. The sun gear 21A of the first planetary gear speed reducer 12A, the planetary carrier 23A of the first planetary gear speed reducer 12A, and S and C on the right side are the sun gear 21B and second planet of the second planetary gear speed reducer 12B, respectively. The planetary carriers 23B, R of the gear reducer 12B represent the ring gears 24A, 24B, BRK of the first and second planetary gear reducers 12A, 12B, the hydraulic brake 60, and the OWC represents the one-way clutch 50. 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 brake 60 is 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 the vehicle 3 travels 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 brake 60 is controlled to a weakly engaged state. Note that the weak fastening means a state in which power can be transmitted but fastened with a weak fastening force with respect to a fastening force of the hydraulic brake 60 in a fastened state. 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. 50, the hydraulic brake 60 provided in parallel with the first motor is also in a weakly engaged state, and the first and second motors 2A, 2B and the rear wheel Wr are connected, so that the first and second motors 2A, 2B can be connected. Even when the forward torque input of the motor is temporarily reduced and the one-way clutch 50 is disengaged, power cannot be transmitted between the first and second motors 2A, 2B and the rear wheel Wr. Can be suppressed. 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. The fastening force of the hydraulic brake 60 when the one-way clutch 50 is engaged is made weaker than the fastening force of the hydraulic brake 60 when the one-way clutch 50 is not engaged. Energy consumption is reduced.

  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 brake 60 is 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 brake 60 is 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. However, the hydraulic brake 60 provided in parallel with the one-way clutch 50 is fastened, and the first and second electric motors 2A, 2B and the rear wheel Wr are kept in a connected state so that power can be transmitted. 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 brake 60 is controlled to the 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 ring gear 24A is controlled by controlling the hydraulic brake 60 to the released state. , 24B begins 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 brake 60 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 cut off and cannot transmit power. It becomes a state. 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.

  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 brake 60 is controlled to be engaged. Accordingly, the ring gears 24A and 24B are locked, the planetary carriers 23A and 23B rotate in the reverse direction, and the vehicle 3 travels 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 brake 60 provided in parallel with the one-way clutch 50 is fastened, and the first and second electric motors 2A, 2B and the rear wheel Wr can be connected to keep power transmission. The vehicle 3 can be moved backward by the torque of the first and second electric motors 2A, 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. The engagement / release of the hydraulic brake 60 is controlled according to which power is input from the rear wheel Wr side, and the engagement force is adjusted even when the hydraulic brake 60 is engaged.

Here, the characteristics of the hydraulic brake 60 will be described.
The hydraulic brake 60 is a so-called wet multi-plate brake, and as described above, a plurality of fixed plates 35 and a plurality of rotating plates 36 are alternately arranged in the axial direction, and these plates 35 and 36 are annular. The piston 37 is operated for fastening and releasing. The wet multi-plate brake cools both plates 35 and 36 with oil as cooling oil, and the oil acts as a damper, so that the shock at the time of engagement is gentler than that of the dry clutch.

  The rotating plate 36 that is spline-fitted to the outer peripheral surface of the gear portion 28B of the ring gear 24B has a lower portion located in the oil storage portion T below the case 11, and stores oil as the ring gears 24A and 24B rotate. By stirring up the oil of the part T, the oil stirring resistance acts on the rotating plate 36. The stirring resistance force due to oil varies depending on the viscosity of the oil. Further, it is known that there is an inverse correlation between the viscosity of the oil and the temperature (oil temperature). The viscosity decreases as the oil temperature increases, and the viscosity increases as the oil temperature decreases. Therefore, the oil viscosity acquisition means for acquiring the oil viscosity may be a viscosity sensor that directly detects or estimates the oil viscosity, or may be a temperature sensor that detects the oil temperature having an inverse correlation with the oil viscosity. The control device 8 can acquire (detect, calculate, estimate) the viscosity of the oil from these sensor values.

  Normally, when the viscosity of the oil is small, the rotational loss of the first and second electric motors 2A, 2B is larger than the rotational loss of the ring gears 24A, 24B, so that the hydraulic brake 60 is released as shown in FIG. The rotation of the first and second electric motors 2A and 2B gradually decreases and eventually stops. However, if the viscosity of the oil is large, the rotation loss of the ring gears 24A, 24B also increases, and a situation may occur in which the first and second electric motors 2A, 2B continue to rotate at a predetermined rotational speed corresponding to the viscosity.

  Therefore, the control device 8 performs brake release loss reduction control when the first and second electric motors 2A, 2B are accompanied by the forward high vehicle speed and when the hydraulic brake 60 is released.

<Brake release loss reduction control>
In the brake release loss reduction control, the first and second electric motors 2A and 2B are controlled at a convergence rotational speed that is the rotational speed at which the accompanying state of the first and second electric motors 2A and 2B converges when the hydraulic brake 60 is released. The rotation control is composed of the rotation control for rotation and the low rotation control for rotating the first and second electric motors 2A, 2B at a rotation speed lower than the convergence rotation speed with the hydraulic brake 60 released.

(Convergence rotation control)
As shown in FIG. 11, the convergent rotation control is performed at a convergent rotational speed, ie, zero torque, which is the rotational speed at which the accompanying state of the first and second electric motors 2A and 2B converges when the hydraulic brake 60 is released. Since the control is to rotate the first and second motors 2A and 2B at the rotational speed at which the first and second motors 2A and 2B rotate, there is basically no power consumption but the first and second motors 2A and 2B. (Accurately, since the rotors 15A and 15B of the first and second electric motors 2A and 2B) are brought together, the loss may increase.

(Low rotation control)
As shown in FIG. 12, the low rotation control is a control for rotating the first and second electric motors 2A and 2B at a lower rotation speed than the convergence rotation speed when the hydraulic brake 60 is released. Although the initial power for lowering the electric motors 2A and 2B from the convergence rotational speed to a desired rotational speed and the maintenance power for continuing to rotate the first and second electric motors 2A and 2B at the rotational speed are required, the rotational speed with low loss is required. Can be arbitrarily selected.

  When the hydraulic brake 60 is released, the control device 8 as the electric motor control device obtains the convergent rotation speed from the vehicle speed and the viscosity at the time of forward high vehicle speed and when the viscosity of the oil is large. The convergence rotational speed is obtained in advance based on the vehicle speed and the viscosity, and is stored in the storage unit of the control device 8. When the control device 8 selects one of the convergence rotation control and the low rotation control, for example, if the vehicle speed is equal to or higher than a predetermined threshold, the controller 8 determines that the loss is large and selects the low rotation control. If it is less than this, it is judged that the loss is not so large, and the convergent rotation control can be selected. The control device 8 may make a selection based on the rotation speed of the motor or the rotation speed of another rotating body instead of the vehicle speed.

  Further, the control device 8 estimates the high vehicle speed travel time from the peripheral information such as road conditions and traffic conditions, selects the low rotation control when the estimated time is long, and selects the low speed control when the estimated time is short. A convergent rotation control may be selected. Furthermore, the control device 8 can determine the operating point in the low rotation control based on the total loss map acquired in advance and stored in the storage unit. The total loss map is for initial power for setting the first and second electric motors 2A and 2B to a predetermined rotational speed lower than the convergence rotational speed and for continuously rotating the first and second electric motors 2A and 2B at the predetermined rotational speed. It is set based on the estimated power consumption obtained from the rotation maintaining power and the loss when the first and second motors 2A, 2B rotate at the convergence rotational speed.

  As described above, according to the present embodiment, the control device 8 has a high oil viscosity, and when the hydraulic brake 60 is released, the first and second electric motors 2A and 2B are accompanied by The first and second electric motors 2A and 2B are rotated at a lower rotational speed than the convergence rotational speed, which is the rotational state amount in which the accompanying state of the first and second electric motors 2A and 2B converges when the hydraulic brake 60 is released. By performing the low rotation control, the first and second electric motors 2A and 2B can be rotated at an efficient operating point, and loss can be reduced.

  Further, the control device 8 converges the first and second electric motors 2A and 2B when the oil viscosity is high and the first and second electric motors 2A and 2B are rotated with the hydraulic brake 60 released. By performing the convergent rotation control to rotate at the rotation speed, the initial power for setting the first and second motors 2A, 2B to the desired rotation speed and the first and second motors 2A, 2B are rotated at the desired rotation speed. It is possible to eliminate the need for the rotation maintaining power for continuing the operation.

  Further, the control device 8 converges the first and second electric motors 2A and 2B when the oil viscosity is high and the first and second electric motors 2A and 2B are rotated with the hydraulic brake 60 released. Estimated power consumption obtained from initial power for setting a predetermined rotational speed lower than the rotational speed, and rotation maintaining power for continuing to rotate the first and second motors 2A, 2B at the predetermined rotational speed, and the first and second By selecting one of the low rotation control and the convergence rotation control based on the loss when the electric motors 2A and 2B rotate at the convergence rotation speed, the loss when the oil viscosity is high can be reduced.

  Further, the control device 8 performs low rotation control when the vehicle speed or the vehicle speed related value is equal to or higher than a predetermined value, that is, when the first and second electric motors 2A and 2B have a high rotational speed, and the vehicle speed or the vehicle speed related value is When the rotational speed of the first and second electric motors 2A and 2B is low when the speed is lower than the predetermined vehicle speed, the control of the rotational speed of the first and second motors 2A and 2B can be easily performed while reducing the loss when the oil viscosity is high.

  Further, the convergence rotational speeds of the first and second electric motors 2A and 2B are obtained based on the viscosity and the vehicle speed or the vehicle speed related value, and are stored in the storage unit, so that the control can be facilitated.

In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.
For example, the wet multi-plate hydraulic brake is exemplified as the connecting / disconnecting means, but a wet multi-plate clutch may be used.
Further, as long as the electric motor and the wheel are connected via the connecting / disconnecting means, the transmission is not necessarily required. When the electric motor and the wheel are connected via the transmission, the transmission can be appropriately selected. is there.
The left and right wheels are not limited to being driven by separate electric motors, and the left and right wheels may be driven by a single electric motor.

1 Rear wheel drive device (drive device)
2A 1st electric motor (electric motor)
2B Second electric motor (electric motor)
3 vehicle 8 control device (connection / disconnection means control device, connection / disconnection means control device)
60 Hydraulic brake (connection / disconnection means)
Wr Rear wheel (wheel)

Claims (5)

An electric motor that generates the driving force of the vehicle;
An electric motor control device for controlling the electric motor;
A wet multi-plate type connecting / disconnecting means which is provided on a power transmission path between the electric motor and the wheel of the vehicle, and which disconnects or connects the electric motor side and the wheel side by releasing or fastening;
A connecting / disconnecting means control device for controlling switching between a disconnecting state and a connecting state of the connecting / disconnecting means, and a driving device comprising:
The motor control device is configured such that when the liquid fluid used for cooling the multi-plate portion of the wet multi-plate type connecting / disconnecting means has a high viscosity, the motor is accompanied with the connecting / disconnecting means released. A drive device that performs low rotation control to rotate the motor with a rotation state amount smaller than a convergence rotation state amount that is a rotation state amount that the rotation of the electric motor converges in a state where the connection / disconnection means is released . The drive device according to claim 1,
The electric motor control device is configured such that when the liquid fluid is high in viscosity and the connecting / disconnecting means is released, the electric motor is accompanied by the converging rotation state amount in a state where the connecting / disconnecting means is released. A driving device that performs convergent rotation control for rotating an electric motor. The drive device according to claim 2,
The electric motor control device sets the electric motor to a rotational state amount smaller than the convergent rotational state amount when the liquid fluid has a high viscosity and the motor is accompanied with the connection / disconnection means released. On the basis of the estimated power consumption obtained from the initial power for rotation and the rotation maintaining power for continuing to rotate the motor at the rotational state quantity, and the loss when the motor rotates at the convergent rotational state quantity. A drive device that selects one of rotation control and convergent rotation control. The drive device according to claim 2,
The electric motor control device performs the low rotation control when the vehicle speed or the vehicle speed related value is equal to or greater than a predetermined value, and performs the convergent rotation control when the vehicle speed or the vehicle speed related value is less than the predetermined value. The drive device according to any one of claims 1 to 4,
The convergent rotation state quantity is obtained based on the viscosity and a vehicle speed or a vehicle speed related value, and is stored in a storage unit.

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