JP2010002013A - Driving force distribution control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving force distribution control device for a vehicle, reducing consumption loss of oil pressure while securing responsiveness. <P>SOLUTION: This driving force distribution control device 26 includes clutches C1, C2, the engagement states of which are controlled by oil pressure, wherein the distribution of driving force to a pair of right and left rear wheels 30 is controlled through the clutches C1, C2, according to an electric command, the opened and closed state is controlled, and the device includes oil pressure retaining valves 68, 70 for retaining the oil pressure in the clutches C1, C2 in the closed state, and a driving force distribution controller 34 for outputting a command to control the opened and closed state of the oil pressure retaining valves 68, 70 according to the running state of the vehicle. Thus, when the engagement of the clutches C1, C2 is maintained, the oil pressure retaining valves 68, 70 are put in the closing state to restrain consumption loss of oil pressure. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicular driving force distribution control device that distributes a driving force to a pair of left and right driving wheels in a vehicle, and more particularly, to an improvement for reducing loss of hydraulic pressure while ensuring responsiveness.

  A vehicle driving force distribution control device that includes a hydraulic engaging device that is controlled by hydraulic pressure and that controls the distribution of driving force to a pair of left and right driving wheels via the hydraulic engaging device is known. It has been. For example, the vehicle driving force distribution device described in Patent Document 1 is that. According to this technique, it is possible to control the torque difference between the left and right drive wheels by controlling the hydraulic pressure supplied to the hydraulic engagement device for controlling the transmission of the drive force to the pair of drive wheels. The differential limiting control is performed to limit the differential between the pair of drive wheels as necessary.

JP 2007-278379 A

  However, in the conventional vehicle power distribution control device as described above, an electric hydraulic pump is generally used as a hydraulic power source of the hydraulic engagement device. However, when differential limiting control of the pair of drive wheels is performed. In order to maintain the engagement of the hydraulic engagement device corresponding to each drive wheel, it is necessary to always supply a predetermined hydraulic pressure, which may cause a loss of hydraulic pressure consumption. In addition, when the output of the electric hydraulic pump is reduced in order to suppress such oil pressure consumption loss, the responsiveness of the hydraulic engagement device may be deteriorated. For this reason, there has been a demand for the development of a vehicle driving force distribution control device that reduces the consumption loss of hydraulic pressure while ensuring responsiveness.

  The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a vehicle driving force distribution control device that reduces hydraulic power consumption loss while ensuring responsiveness. .

  In order to achieve such an object, the gist of the present invention includes a hydraulic engagement device whose engagement state is controlled by hydraulic pressure, and a pair of left and right drive wheels via the hydraulic engagement device. A vehicle driving force distribution control device for controlling the distribution of driving force to the vehicle, wherein the open / close state is controlled by an electrical command, and the hydraulic pressure holding device holds the hydraulic pressure in the hydraulic engagement device in the closed state It is characterized by comprising a valve and a control device for outputting a command for controlling the open / close state of the hydraulic pressure holding valve in accordance with the running state of the vehicle.

  According to this configuration, the vehicle drive includes the hydraulic engagement device whose engagement state is controlled by hydraulic pressure, and controls the distribution of the driving force to the pair of left and right drive wheels via the hydraulic engagement device. In the force distribution control device, the open / close state is controlled by an electrical command, and a hydraulic pressure holding valve that holds the hydraulic pressure in the hydraulic engagement device in the closed state, and the hydraulic pressure holding valve according to the traveling state of the vehicle A control device that outputs a command for controlling the open / closed state of the hydraulic pressure control device. Therefore, in a state where the engagement of the hydraulic engagement device is maintained, the hydraulic pressure holding valve is closed. Hydraulic power consumption loss can be suppressed. That is, it is possible to provide a vehicular driving force distribution control device that reduces hydraulic power consumption loss while ensuring responsiveness.

  Here, preferably, the hydraulic engagement device includes a pair of clutches provided between an input member and an axle corresponding to each of the pair of drive wheels, and the control device includes: When the execution of the differential restriction control of the pair of drive wheels is determined, the hydraulic holding valves corresponding to the pair of clutches are closed. In this way, in the driving force distribution control device provided with a hydraulic engagement device having a practical configuration, it is possible to reduce hydraulic oil consumption loss while ensuring responsiveness.

  Preferably, a planetary gear device is provided between the input member and the axle, and the hydraulic engagement device is provided with a brake provided between the non-rotating member and the carrier of the planetary gear device. When the execution of torque distribution control of the pair of driving wheels is determined, the control device closes the hydraulic pressure holding valve corresponding to the brake. In this way, in the driving force distribution control device provided with a hydraulic engagement device having a practical configuration, it is possible to reduce hydraulic oil consumption loss while ensuring responsiveness.

  Preferably, the control device corresponds to a release-side clutch among the hydraulic pressure holding valves respectively corresponding to the pair of clutches when shifting from the differential restriction control to the torque distribution control of the pair of drive wheels. The hydraulic pressure holding valve that is to be opened is immediately opened, and the hydraulic pressure holding valve corresponding to the clutch on the engagement side is shifted to the opened state at a predetermined rate of change. In this way, particularly when shifting from the differential restriction control to the torque distribution control of the pair of drive wheels, it is possible to reduce the hydraulic consumption loss while ensuring the responsiveness.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 illustrates a configuration of a driving force transmission device 10 for a front and rear wheel drive vehicle based on a front engine front wheel drive (FF) equipped with a vehicle driving force distribution control device 26 to which the present invention is preferably applied. FIG. In the vehicle shown in FIG. 1, the driving force (torque) generated by the engine 12 serving as a driving force source is generated by the automatic transmission 14, the front wheel differential gear device 16, and the pair of left and right front wheel axles 18l and 18r ( Hereinafter, if not particularly distinguished, it is simply transmitted to a pair of left and right front wheels 20l and 20r (hereinafter simply referred to as front wheel 20 unless otherwise distinguished) via a front wheel axle 18). Center differential) 22, propeller shaft 24 that is a driving force transmission shaft, driving force distribution control device 26 that is an embodiment of the present invention, and a pair of left and right rear axles 28l and 28r (hereinafter, unless otherwise distinguished, simply (Referred to as “rear wheel 30” unless otherwise specified). Here, as shown in FIG. 1, in the driving force transmission device 10, the rotation shaft of the rear wheel 30 and the rotation of the propeller shaft 24 as the driving wheels related to the distribution of the driving force by the driving force distribution control device 26. The shafts are arranged so as to be orthogonal to each other. The driving force transmission device 10 includes a hydraulic circuit 32 that controls the hydraulic pressure for controlling the engagement state of the hydraulic engagement device provided in the driving force distribution control device 26, and the hydraulic circuit 32. A driving force distribution controller 34 is provided as a control device for controlling the hydraulic pressure supplied from the hydraulic circuit 32 into the driving force distribution control device 26 via an electromagnetic control valve (not shown) provided in FIG. . In FIG. 1, the hydraulic pressure output from the hydraulic circuit 32 is indicated by thin broken arrows, and the control signal (control command) output from the driving force distribution controller 34 and the input signals from various sensors are indicated by thin dotted arrows. ing.

  The engine 12 is, for example, an internal combustion engine such as a gasoline engine or a diesel engine that generates driving force by combustion of fuel injected in a cylinder. The automatic transmission 14 is, for example, a stepped automatic transmission (automatic transmission) that outputs the rotation input from the engine 12 by decelerating or increasing the speed at a predetermined gear ratio γ. Any one of the first gear, the reverse gear, and the neutral is selectively established, and the speed conversion corresponding to each gear ratio γ is performed. The input shaft of the automatic transmission 14 is connected to the output shaft of the engine 12 via a torque converter (not shown).

  The driving force distribution controller 34 includes a CPU, a ROM, a RAM, an input / output interface, and the like, and uses a temporary storage function of the RAM to execute signal processing according to a program stored in advance in the ROM. For example, by controlling the command value of the current supplied to the electromagnetic control valve provided in the hydraulic circuit 32, the hydraulic pressure supplied to the engagement element provided in the driving force distribution control device 26 is controlled. As a result, various controls such as differential limit control and yaw control, which will be described later, are executed. In order to execute such control, vehicle speed determination means 36, turning determination means 38, engagement control means 40, hydraulic pressure holding valve control means 42, and hydraulic pump drive control means 43 are functionally provided. These control functions will be described later with reference to FIGS. The power transmission device 10 includes a wheel speed sensor 44 that detects the actual rotational speed of each of the left and right rear wheels 30l and 30r, a steering angle sensor 46 that detects a steering angle of a steering wheel (not shown), and a power transmission device 10 (not shown). Various sensors such as an accelerator opening sensor 48 for detecting an accelerator opening corresponding to the amount of depression of the accelerator pedal are provided, and a signal indicating a vehicle speed, a signal indicating a steering angle of a steering wheel, and an accelerator opening from each sensor. Is input to the driving force distribution controller 34.

  FIG. 2 is a skeleton diagram illustrating the configuration of the driving force distribution control device 26. As shown in FIG. 2, the driving force distribution control device 26 includes, for example, a bevel gear 50 connected to an end of a propeller shaft 24 that is rotationally driven by the engine 12 via a central differential gear device 22. The bevel gear 52 meshes with the bevel gear 50, and the driving force is input via the pair of bevel gears 50 and 52. A differential 54 for distributing the driving force transmitted from the propeller shaft 24 via the bevel gears 50 and 52 to the left and right rear wheels 30l and 30r, and provided adjacent to the differential 54. The transmission 56 arranged coaxially with the rear axles 28l and 28r, and the first clutch C1 which is an engagement element for selectively transmitting the output of the transmission 56 to the differential 54. And the second clutch C2.

  The differential 54 is a first ring gear R1 that is a first rotation element RE1, a plurality of pairs of first pinion gears P1 that mesh with each other, and a second rotation element RE2 that supports the first pinion gears P1 so as to be able to rotate and revolve. A double pinion type planetary gear device including a first carrier CA1 and a first sun gear S1 that is a third rotating element RE3 that meshes with the first ring gear R1 via the plurality of pairs of first pinion gears P1, and the gear ratio thereof. ρ (= number of teeth of first sun gear S1 / number of teeth of first ring gear R1) is set to 0.5, for example. The first ring gear R1 is provided integrally with the case 58 in the case 58 of the differential 54, and the rotation of the propeller shaft 24 is decelerated by the bevel gears 50 and 52, and the first ring gear R1. To be communicated to. That is, in the present embodiment, the case 58 functions as an input member. The first carrier CA1 is connected to the left rear wheel 30l via the left rear wheel axle 28l. The first sun gear S1 is coupled to the right rear wheel 30r via the right rear wheel axle 28r. The second rotating element RE2 and the third rotating element RE3 can be replaced, and the same applies to the following description.

  The transmission 56 includes a second sun gear S2, which is a fifth rotating element RE5, a second pinion gear P2, a second carrier CA2 which is a sixth rotating element RE6 that supports the second pinion gear P2 so as to be capable of rotating and revolving, and the above. A single pinion type planetary gear device including a second ring gear R2 that is a fourth rotating element RE4 meshing with the second sun gear S2 via the second pinion gear P2 is provided. The fifth rotation element RE5 is connected to the first rotation element RE1 and functions as an input member of the transmission 56, like the case 58. The sixth rotation element RE6 is connected to a brake B that is an engagement element for switching torque movement, and is selectively connected to the non-rotating member 60 via the brake B. . The fourth rotation element RE4 is caused to function as an output member of the transmission 56. The fourth rotating element RE4 is selectively slip-engaged or completely engaged with the first carrier CA1 and the left rear wheel axle 28l of the differential device 54, which is the second rotating element RE2, via the first clutch C1. At the same time, it is selectively slip-engaged or completely engaged with the first sun gear S1 and the right rear wheel axle 28r of the differential 54 which is the third rotating element RE3 via the second clutch C2. The brake B, the first clutch C1, and the second clutch C2 are each preferably a multi-plate hydraulic friction engagement device capable of slip engagement, and a control command from the driving force distribution controller 34. Engagement or disengagement is performed by the hydraulic pressure output from the hydraulic circuit 32 controlled according to the control, and the transmission torque at the time of slip engagement is controlled by performing the hydraulic control as necessary.

  Returning to FIG. 1, the engagement control means 40 provided in the driving force distribution controller 34 includes the first clutch C <b> 1, the second clutch C <b> 2, and the brake B as engagement elements via the hydraulic circuit 32. By controlling the engagement state, the driving force control for controlling the transmission of the driving force generated by the engine 12 to the left and right rear wheels 30l, 30r is executed. The driving force generated by the engine 12 is input as a driving force for rotationally driving the case 58 of the differential device 54 via the automatic transmission 14, the central differential gear device 22, the propeller shaft 24, and the like. The Since the first ring gear R1 of the differential device 54 is provided integrally with the case 58, the driving force from the propeller shaft 24 is transmitted from the first ring gear R1 through the case 58 as an input member. Input to the differential 54. The engagement control means 40 supplies the hydraulic pressure supplied from the hydraulic circuit 32 to the first clutch C1, the second clutch C2, and the brake B via an electromagnetic control valve or the like provided in the hydraulic circuit 32 described later. By controlling, the engagement elements are controlled to be in an engaged state, a slip engaged state, or a released state. In this way, the engagement states of the first clutch C1, the second clutch C2, and the brake B are controlled, so that the driving force input to the differential 54 is applied to the left and right rear wheels 30l and 30r. Distribution is controlled. Hereinafter, the distribution of the driving force to the left and right rear wheels 30l and 30r by the driving force distribution control device 26 will be described in detail.

  3 to 6 are collinear diagrams showing the rotational speeds of a plurality of rotating elements in the differential device 42 of the driving force distribution control device 26. FIG. In these collinear diagrams, the left vertical axis represents the rotation speed Nl of the first carrier CA1 that is the second rotation element RE2 connected to the left rear wheel 30l, and the right vertical axis connected to the right rear wheel 30r. The rotation speed Nr of the third rotation element RE3 is shown, and the central vertical axis indicates the rotation speed Ni of the first ring gear R1, which is the first rotation element RE1 rotated together with the case 58, and the fourth rotation element RE4. The rotation speed Nc is shown. Further, the table shown on the right side of the figure shows the state of the brake B, the first clutch C1, and the second clutch C2, "◯" indicates the engaged state, and "X" indicates the released state. . The straight line between the rotational speeds Nl and Nc indicates the state of the first clutch C1, and the solid line indicates the slip engagement state and the broken line indicates the released state. A straight line between the rotational speed Nc and the rotational speed Nr indicates the state of the second clutch C2, and a solid line indicates slip engagement and a broken line indicates a released state.

  FIG. 3 is an alignment chart when the driving force distribution control device 26 is not controlled. At the time of non-control, the brake B, the first clutch C1, and the second clutch C2, which are engaging elements, are in a released state. In this state, only the differential device 54 functions and the transmission device 56 is idled, so that the driving force is evenly distributed to the left and right rear wheels 30l, 30r. Thereby, the driving force distribution control device 26 does not perform torque movement and differential limitation, and functions as a normal open differential. Further, when traveling straight, the differential device 54 is integrally rotated as shown in FIG. 3, and the rotational speeds Nl and Nr of the left and right rear wheels 30l and 30r are substantially the same.

  FIG. 4 is an example of a nomograph during yaw control control, that is, left and right wheel torque distribution control (left and right wheel torque difference control). For example, during left turn, the driving force of the right rear wheel 30r is increased to suppress understeer. It is an alignment chart of the state made to do. In the mode shown in FIG. 4, the brake B is engaged, the first clutch C1 is slip-engaged, and the second clutch C2 is released. Thus, when the brake B is engaged, the second carrier CA2 of the transmission 56 is locked, and the rotation speed Nc of the fourth rotation element RE4 is decelerated in the reverse rotation direction and output. Further, when the first clutch C1 is slip-engaged, the output of the fourth rotating element RE4 is transmitted to the second rotating element RE2. Here, since the rotation speed Nc of the fourth rotation element RE4 is decelerated in the reverse rotation direction, the driving force of the left rear wheel 30l is reduced by the slip engagement of the first clutch C1, while the right The driving force of the rear wheel 30r is relatively increased. Further, since the rotational speed Nl of the left rear wheel 30l is decelerated by slip engagement, the differential rear device 54 increases the speed of the right rear wheel 30r.

  For example, during a right turn or the like, as shown in FIG. 5, the driving force of the left rear wheel 30l can be increased to suppress understeer. In the embodiment shown in FIG. 5, the brake B is engaged, the second clutch C2 is slip-engaged, and the first clutch C1 is released. As in FIG. 4, when the brake B is engaged, the second carrier CA2 of the transmission 56 is locked, and the rotation speed Nc of the fourth rotation element RE4 is decelerated in the reverse direction and output. Further, when the second clutch C2 is slip-engaged, the output of the fourth rotating element RE4 is transmitted to the third rotating element RE3. Here, since the rotation speed of the fourth rotation element RE4 is decelerated in the reverse rotation direction, the driving force of the right rear wheel 30r is reduced while the second clutch C2 is slip-engaged. The driving force of the left rear wheel 30l is relatively increased. Further, since the rotational speed Nr of the right rear wheel 30r is decelerated by slip engagement, the differential rear device 54 increases the speed of the left rear wheel 30l.

  FIG. 6 is an alignment chart at the time of left and right wheel differential restriction control. At the time of differential limiting control for limiting the differential rotation of the pair of rear wheel axles 28 (or rear wheels 30), the brake B is released and the first clutch C1 and the second clutch C2 are Are engaged together. In this way, the first clutch C1 and the second clutch C2 are engaged together, so that the relative rotation of the left and right rear wheel axles 28l, 28r is limited, and thereby the left and right rear wheels 30l, 30r Differential limiting is performed. Here, when both the first clutch C1 and the second clutch C2 are completely engaged, they function as a non-slip differential, and the left and right rear wheels 30l and 30r rotate in the same direction. The differential limiting force can be arbitrarily set in proportion to the clutch control torque.

  Returning to FIG. 1, the engagement control means 40 determines that there is a possibility that a control request for the driving force control, that is, the transmission control of the driving force to the left and right rear wheels 30 l and 30 r is made from a predetermined reference. If it is determined that there is a possibility that the control request is made, the engagement states of the brake B, the first clutch C1, and the second clutch C2, which are the engagement elements, are determined based on the driving force control. Preliminary control for performing control up to the previous stage is executed. The vehicle speed determination means 36 and the turning determination means 38 function as control request determination means for determining whether or not there is a possibility that the control request is made for such preliminary control. The vehicle speed determination means 36 determines whether or not the vehicle speed is equal to or lower than a predetermined vehicle speed based on a signal representing the vehicle speed supplied from the wheel speed sensor 44. The turning determination unit 38 determines whether or not the vehicle is turning based on a signal representing the steering angle supplied from the steering angle sensor 46.

  When it is determined that there is a possibility that the control request for the driving force control corresponding to the differential limiting control for limiting the differential control of the left and right rear wheels 30l, 30r is made, that is, the engagement control means 40, When the determination of the vehicle speed determination means 36 is affirmative, preliminary control for controlling the engagement state of the engagement element provided in the driving force distribution control device 26 until the previous stage of executing the differential limiting control. Execute. Specifically, the engagement of each of the first clutch C1 and the second clutch C2, which are engaging elements involved in the differential limit control, so that the torque transmission capacity is weaker than the torque transmission capacity in the differential limit control. Control the status. The torque transmission capacity at the time of the preliminary control is preferably equivalent to a fastening force at which so-called backlashing is completed until the piston for engaging each engaging element is brought into a state of pressing the friction plate. The hydraulic actuators of the first clutch C1 and the second clutch C2 so that the torque transmission capacity is as strong as possible within the limit that the influence on the differential state of the left and right rear wheels 30l, 30r is negligible. The hydraulic pressure supplied to is controlled. Further, in the preliminary control of such differential limiting control, the control of the brake B is not performed and is left released.

  FIG. 7 is a table summarizing the engagement state of each engagement element in the preliminary control by the engagement control means 40. As shown in the table of FIG. 7, in the preliminary control by the engagement control means 40, when the vehicle starts or runs at a low speed, the first clutch C1 and the second clutch C2 are in a relatively weak engagement state, that is, so-called backlash. The engaged state is such that the filling is completed. During straight running such as when the vehicle starts or runs at low speed, there are many driving scenes that require traction performance, and there are many scenes where a control request for differential limiting control is output. In this way, the first clutch By pre-filling the backlash of C1 and the second clutch C2, it is possible to shorten the time from when the actual control request is output until the substantial engagement control of each engagement element is started. It is possible to improve the response of the differential limit control. Further, the brake B is completely engaged when the vehicle is traveling at a medium speed or a high speed. When the vehicle is running at medium to high speed, there are many driving scenes that require steering follow-up, and there are many scenes where control requests for left and right wheel torque difference control (yaw control control) are output. By completely engaging B, the time required from the actual control request being output until the substantial engagement of each engagement element is completed can be shortened. Responsiveness can be improved.

FIG. 8 is a circuit diagram illustrating the configuration of the hydraulic circuit 32. As shown in FIG. 8, the hydraulic circuit 32 is based on an electric hydraulic pump 64 that functions as a hydraulic source that pumps hydraulic oil that has been returned to the oil pan 62, and the hydraulic pressure generated by the hydraulic pump 64. the line pressure P _L temper pressure regulating pressure accumulator 66 as pressure, the control pressure (first first clutch C1 according from a more regulated line pressure P _L to the pressure regulating accumulator 66 to the command of the driving force distribution controller a first linear solenoid valve SL1 for pressurizing regulates the hydraulic) P _C1 supplied to the actuator provided in the clutch C1, the control oil pressure of the second clutch C2 in response to an instruction of the driving force distribution controller from the line pressure P _L ( a second linear solenoid valve SL2 for pressurizing the hydraulic pressure) P _C2 supplied to the actuator provided in the second clutch C2 tone, the line And a third linear solenoid valve SL3 that pressure regulating the P _B (oil supplied to the actuator provided in the brake B) control oil pressure of the brake B according from P _L to an instruction of the driving force distribution controller is configured to include ing.

  In the hydraulic circuit 32, the hydraulic pressure in the first clutch C1 is maintained in the closed state (on state) corresponding to the first clutch C1 (the hydraulic oil from the actuator provided in the first clutch C1). A first hydraulic pressure holding valve 68 that releases (drains) the hydraulic pressure in the first clutch C1 in the open state (off state) is provided. Similarly, the hydraulic pressure in the second clutch C2 is maintained in the closed state (on state) corresponding to the first clutch C2 (preventing the hydraulic oil from flowing out from the actuator provided in the second clutch C2). On the other hand, a second hydraulic pressure holding valve 70 is provided that releases (drains) the hydraulic pressure in the second clutch C2 in the open state (off state). The first hydraulic pressure holding valve 68 and the second hydraulic pressure holding valve 70 are, for example, generally well-known pilot check valves whose open / closed states are controlled by electrical commands, and according to the commands from the driving force distribution controller. Thus, the open / close state is controlled.

  Returning to FIG. 1, the hydraulic pressure holding valve control means 42 provided in the driving force distribution controller 34 controls the open / closed state of the first hydraulic pressure holding valve 68 and the second hydraulic pressure holding valve 70 according to the traveling state of the vehicle. Command to output. Preferably, when it is determined that the differential restriction control of the pair of rear wheels 30 is to be executed, that is, when the differential restriction control is executed by the engagement control means 40, the first hydraulic pressure holding valve 68 and the second hydraulic pressure holding valve are held. A command for closing both valves 70 (ON state) is output. As described above with reference to FIG. 6, at the time of differential limiting control of the pair of rear wheels 30, the brake B is released and the first clutch C1 and the second clutch C2 are both engaged. . As such, the first hydraulic pressure holding valve is in a state in which the hydraulic pressure for engaging the first clutch C1 and the second clutch C2 is supplied to the actuators provided in the first clutch C1 and the second clutch C2, respectively. When both 68 and the second hydraulic pressure holding valve 70 are closed, the hydraulic pressure is held in the actuators of the first clutch C1 and the second clutch C2. Here, the hydraulic pump drive control means 43 provided in the driving force distribution controller 34 determines that both the first hydraulic pressure holding valve 68 and the second hydraulic pressure holding valve 70 are in a closed state according to a command from the hydraulic pressure holding valve control means 42. In this case, the operating rate (discharge amount) of the hydraulic pump 64 is reduced by a predetermined value compared with the normal time, that is, when both the first hydraulic pressure holding valve 68 and the second hydraulic pressure holding valve 70 are opened. . When both the first hydraulic pressure holding valve 68 and the second hydraulic pressure holding valve 70 are in the closed state, the first clutch C1 and the second clutch are operated by the first hydraulic pressure holding valve 68 and the second hydraulic pressure holding valve 70. Since the hydraulic pressure for engaging C2 is maintained, the differential limiting control of the pair of rear wheels 30 can be preferably continued even if the operating rate of the hydraulic pump 64 is reduced.

  Further, the hydraulic pressure holding valve control means 42 is preferably configured so that the first hydraulic pressure holding valve 68 and the second hydraulic pressure holding valve 68 and the second hydraulic pressure holding valve 68 are changed when the differential restriction control of the pair of rear wheels 30 is shifted to torque distribution control (yaw control control). Among the hydraulic pressure holding valves 70, the hydraulic pressure holding valve corresponding to the release side clutch is immediately opened, and the hydraulic pressure holding valve corresponding to the engagement side clutch is set to a predetermined time change rate (preferably a constant change rate). ) To output a command to shift to the open state. Further, regarding this control, a hydraulic pressure sensor may be provided on the downstream side of the hydraulic pressure holding valves 68 and 70, and feedback control may be performed so that the hydraulic pressure detected by the hydraulic pressure sensor becomes a predetermined command pressure. As described above with reference to FIG. 4, in torque distribution control in which the driving force of the right rear wheel 30r is increased to suppress understeer during a left turn or the like, the first clutch C1 corresponding to the left rear wheel 30l is engaged. And the second clutch C2 corresponding to the right rear wheel 30r is released. When the shift from the differential limiting control shown in FIG. 6 to the torque distribution control shown in FIG. 4 is performed, the hydraulic pressure holding valve control means 42 corresponds to the second hydraulic pressure holding corresponding to the second clutch C2 on the release side. A command for causing the valve 70 to be immediately opened (off state) is output, and a command for shifting the first hydraulic pressure holding valve 68 corresponding to the first clutch C1 on the engagement side from the closed state to the open state at a predetermined change rate. Output. At the time of torque distribution control, the engagement side clutch is slip-engaged or completely engaged as necessary. However, as described above, the clutch is held by the engagement side clutch actuator when shifting from the differential limit control. By gradually reducing the hydraulic pressure and shifting to the hydraulic pressure required for torque distribution control, it is possible to suitably suppress the hydraulic power consumption loss and to shorten the non-reaction time at the time of transition as much as possible. .

  FIG. 9 is a flowchart for explaining a main part of an example of the driving force distribution control by the driving force distribution controller 34, which is repeatedly executed at a predetermined cycle.

  First, in step (hereinafter, step is omitted) S1, it is determined whether execution determination of differential limiting control of the pair of rear wheels 30 is ON based on the detection result of the wheel speed sensor 44 or the like. The When the determination at SA1 is negative, the processing after SA6 is executed. When the determination at SA1 is affirmative, at SA2, the vehicle starts based on the detection result of the wheel speed sensor 44 or the like. It is determined whether it is time. If the determination at SA2 is affirmative, the processing below SA4 is executed. If the determination at SA2 is negative, whether or not the vehicle is traveling at a high speed, that is, whether the vehicle speed is equal to or higher than a predetermined speed, is determined at SA3. Is judged. If the determination at SA3 is negative, the routine is terminated accordingly. If the determination at SA3 is affirmative, the first hydraulic pressure holding valve 68 and the second hydraulic pressure holding valve 70 are determined at SA4. Are both closed (ON state). Next, in SA5, after the operating rate of the hydraulic pump 64 is decreased by a predetermined value, this routine is terminated. In SA6, it is determined whether or not at least one of the first hydraulic pressure holding valve 68 and the second hydraulic pressure holding valve 70 is in a closed state (on state). If the determination at SA6 is negative, the routine is terminated accordingly. If the determination at SA6 is affirmative, the first hydraulic pressure holding valve 68 and the second hydraulic pressure holding valve 70 are determined at SA7. Are both opened (off state). Next, in SA8, after the operating rate of the hydraulic pump 64 is set to the normal state (the operating rate higher than the state reduced in SA5), this routine is ended. In the above control, SA4 and SA7 correspond to the operation of the hydraulic pressure holding valve control means 42, and SA5 and SA8 correspond to the operation of the hydraulic pump drive control means 43, respectively.

  FIG. 10 is a flowchart for explaining a main part of another example of the driving force distribution control by the driving force distribution controller 34, which is repeatedly executed at a predetermined cycle.

  First, in SB1, it is determined whether or not the transition from the differential restriction control to the torque distribution control of the pair of rear wheels 30 is determined based on the detection results of the wheel speed sensor 44, the steering angle sensor 46, and the like. . If the determination at SB1 is negative, the routine is terminated. If the determination at SB1 is affirmative, the torque distribution control determined at SB1 is performed at the right rear wheel 30r at SB2. It is determined whether or not the second clutch C2 corresponding to is engaged. When the determination at SB2 is negative, the processing after SB6 is executed, but when the determination at SB2 is affirmative, a command to engage the brake B is output at SB3. Next, at SB4, a command to immediately open the first hydraulic pressure holding valve 68 provided in the first clutch C1 corresponding to the left rear wheel 301 is output. Next, in SB5, after outputting a command to shift the second hydraulic pressure holding valve 70 provided in the second clutch C2 corresponding to the right rear wheel 30r to the open state at a predetermined rate, this routine is ended. . In SB6, it is determined whether or not the torque distribution control determined in SB1 is to engage the first clutch C1 corresponding to the left rear wheel 30l. If the determination at SB6 is negative, the routine is terminated. If the determination at SB6 is affirmative, a command for engaging the brake B is output at SB7. Next, at SB8, a command to immediately open the second hydraulic pressure holding valve 70 provided in the second clutch C3 corresponding to the right rear wheel 30r is output. Next, in SB9, after outputting a command to shift the first hydraulic pressure holding valve 68 provided in the first clutch C1 corresponding to the left rear wheel 30l to the open state at a predetermined rate, this routine is terminated. . In the above control, SB4, SB5, SB8, and SB9 correspond to the operation of the hydraulic pressure holding valve control means 42.

  FIG. 11 is a circuit diagram illustrating another configuration of the hydraulic circuit 32. In the hydraulic circuit 32, the hydraulic pressure in the first brake B is maintained in the closed state (on state) corresponding to the brake B (while the hydraulic oil is prevented from flowing out from the actuator provided in the brake B), A third hydraulic pressure holding valve 72 that releases (drains) the hydraulic pressure in the brake B in the open state (off state) is provided. The third hydraulic pressure holding valve 72 is, for example, a generally well-known pilot check valve whose open / closed state is controlled by an electrical command, and the open / closed state is controlled according to a command from the driving force distribution controller. It is configured as follows.

  Corresponding to the hydraulic circuit 32 configured as shown in FIG. 11, the hydraulic pressure holding valve control means 42 provided in the driving force distribution controller 34 opens and closes the third hydraulic pressure holding valve 72 according to the running state of the vehicle. A command to control the state is output. Preferably, when the execution of torque distribution control (yaw control control) of the pair of rear wheels 30 is determined, that is, when the torque distribution control by the engagement control means 40 is performed, the third hydraulic pressure holding valve 72 is closed. A command to make a state (ON state) is output. As described above with reference to FIGS. 4 and 5, the brake B is always engaged during torque distribution control of the pair of rear wheels 30. As described above, when the third hydraulic pressure holding valve 72 is closed in a state in which the hydraulic pressure for engaging the brake B is supplied to the actuator provided in the brake B, the inside of the actuator of the brake B Therefore, the hydraulic pressure is maintained. Here, the hydraulic pump drive control means 43 provided in the driving force distribution controller 34 is in a normal state when the third hydraulic pressure holding valve 72 is closed by a command from the hydraulic pressure holding valve control means 42. That is, the operating rate (discharge amount) of the hydraulic pump 64 is reduced by a predetermined value as compared with the case where the third hydraulic pressure holding valve 72 is opened. When the third hydraulic pressure holding valve 72 is in the closed state, the hydraulic pressure for engaging the brake B is held by the third hydraulic pressure holding valve 72, so that the operating rate of the hydraulic pump 64 is increased. Even if it is reduced, the torque distribution control of the pair of rear wheels 30 can be preferably continued.

  FIG. 12 is a flowchart for explaining a main part of an example of the driving force distribution control executed by the driving force distribution controller 34 corresponding to the configuration shown in FIG. 11, and is repeatedly executed at a predetermined cycle. .

  First, in SC1, it is determined whether or not execution determination of torque distribution control of the pair of rear wheels 30 is ON based on detection results of the wheel speed sensor 44, the steering angle sensor 46, and the like. If the determination at SC1 is negative, the routine is terminated accordingly. If the determination at SC1 is affirmative, the routine proceeds to SC2 corresponding to the operation of the hydraulic pressure holding valve control means 42. 3. The hydraulic pressure holding valve 72 is closed (ON state). Next, in SC3 corresponding to the operation of the hydraulic pump drive control means 43, after the operating rate of the hydraulic pump 64 is decreased by a predetermined value, this routine is terminated.

  Thus, according to this embodiment, the hydraulic engagement device whose engagement state is controlled by hydraulic pressure is provided, and the driving force is distributed to the pair of left and right rear wheels 30 via the hydraulic engagement device. In the vehicular driving force distribution control device 26 that controls the open / close state of the vehicle, an open / close state is controlled by an electrical command, and in the closed state, a hydraulic holding valve 68 that holds the hydraulic pressure in the hydraulic engagement device, Since the drive force distribution controller 34 for outputting a command for controlling the open / close state of the hydraulic pressure holding valve 68 or the like according to the traveling state is provided, the engagement of the hydraulic engagement device is maintained. In this state, the hydraulic pressure consumption loss can be suppressed by closing the hydraulic pressure holding valve 68 and the like. That is, it is possible to provide the vehicle driving force distribution control device 26 that reduces the hydraulic oil consumption loss while ensuring responsiveness.

  The hydraulic engagement device includes a pair of clutches C1 and C2 provided between a case 58 as an input member and the rear wheel axle 28 corresponding to each of the pair of rear wheels 30. And when the execution of the differential restriction control of the pair of rear wheels 30 is determined, the driving force distribution controller 34 closes the hydraulic pressure holding valves 68 and 70 corresponding to the pair of clutches C1 and C2, respectively. Therefore, in the driving force distribution control device 26 including the hydraulic engagement device having a practical configuration, it is possible to reduce the hydraulic pressure consumption loss while ensuring the responsiveness.

  Further, a transmission device 56 comprising a planetary gear device is provided between the case 58 as an input member and the rear wheel axle 28, and the non-rotating member 60 and the carrier CA2 of the transmission device 56 are used as the hydraulic engagement device. The drive force distribution controller 34 is provided with a brake B provided therebetween, and the hydraulic pressure holding valve 72 corresponding to the brake B is determined when it is determined that the torque distribution control of the pair of rear wheels 30 is performed. Therefore, in the driving force distribution control device 26 including the hydraulic engagement device having a practical configuration, it is possible to reduce the hydraulic oil consumption loss while ensuring the responsiveness.

  In addition, the driving force distribution controller 34, among the hydraulic holding valves 68 and 70 corresponding to the pair of clutches C1 and C2, respectively, during the transition from the differential restriction control to the torque distribution control of the pair of rear wheels 30, The hydraulic holding valve corresponding to the release side clutch is immediately opened and the hydraulic holding valve corresponding to the engagement side clutch is shifted to the open state at a predetermined rate of change. When shifting from the differential limiting control of 30 to the torque distribution control, it is possible to reduce the oil consumption loss while ensuring the responsiveness.

  The preferred embodiments of the present invention have been described in detail with reference to the drawings. However, the present invention is not limited to these embodiments, and may be implemented in other modes.

  For example, in the above-described embodiment, as shown in FIG. 8, a configuration in which the first hydraulic pressure holding valve 68 and the second hydraulic pressure holding valve 70 are provided corresponding to the first clutch C1 and the second clutch C2, respectively, and FIG. 11, the configuration in which the third hydraulic pressure holding valve 72 is provided corresponding to the brake B has been described. However, for example, as shown in FIG. 13, the driving force distribution control device 26 is provided with the power distribution control. The first hydraulic pressure holding valve 68, the second hydraulic pressure holding valve 70, and the third hydraulic pressure holding valve 72 corresponding to all the hydraulic engagement devices according to the above, that is, the first clutch C1, the second clutch C2, and the brake B, respectively. May be provided. Also in such a configuration, the above-described control of FIG. 9, control of FIG. 10, control of FIG.

  In the above-described embodiment, the example in which the present invention is applied to the driving force distribution control device 26 that controls the distribution of the driving force to the pair of rear wheels 30l and 30r has been described. However, the present invention is not limited thereto. For example, the present invention may be applied to a driving force distribution control device for front wheels as an alternative to or in addition to the configuration for rear wheels described above.

  In addition, although not illustrated one by one, the present invention is implemented with various modifications within a range not departing from the gist thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a skeleton diagram illustrating a configuration of a driving force transmission device for a front and rear wheel drive vehicle based on a front engine front wheel drive equipped with a vehicle driving force distribution control device to which the present invention is preferably applied. FIG. 2 is a skeleton diagram illustrating a configuration of a driving force distribution control device provided in the driving force transmission device of FIG. 1. FIG. 3 is a collinear diagram showing the number of rotations of each rotating element when the driving force distribution control device of FIG. 2 is not controlled. FIG. 3 is a collinear diagram showing the number of rotations of each rotating element during left-right wheel torque control of the driving force distribution control device of FIG. 2. FIG. 3 is a collinear diagram showing the number of rotations of each rotating element during left-right wheel torque control of the driving force distribution control device of FIG. 2. FIG. 3 is a collinear diagram showing the number of rotations of each rotating element during differential limiting control of the driving force distribution control device of FIG. 2. 2 is a table summarizing engagement states of respective engagement elements in preliminary control of driving force control by a driving force distribution controller provided in the vehicle of FIG. 1. FIG. 3 is a circuit diagram illustrating a configuration of a hydraulic circuit provided in the driving force distribution control device of FIG. 2. 2 is a flowchart for explaining a main part of an example of driving force distribution control by a driving force distribution controller provided in the vehicle of FIG. 1. 6 is a flowchart for explaining a main part of another example of the driving force distribution control by the driving force distribution controller provided in the vehicle of FIG. 1. FIG. 6 is a circuit diagram illustrating another configuration of the hydraulic circuit provided in the driving force distribution control device of FIG. 2. FIG. 12 is a flowchart for explaining a main part of an example of driving force distribution control executed by a driving force distribution controller provided in the vehicle of FIG. 1 corresponding to the configuration shown in FIG. 11. FIG. 6 is a circuit diagram illustrating still another configuration of a hydraulic circuit provided in the driving force distribution control device of FIG. 2.

Explanation of symbols

26: Vehicle driving force distribution control device 28: Rear wheel axle 30: Rear wheel (drive wheel)
34: Driving force distribution controller (control device)
56: Transmission (planetary gear device)
58: Case (input member)
60: non-rotating member 68: first hydraulic pressure holding valve 70: second hydraulic pressure holding valve 72: third hydraulic pressure holding valve B: brake (hydraulic engagement device)
C1: First clutch (hydraulic engagement device)
C2: Second clutch (hydraulic engagement device)
CA2: Second carrier

Claims (4)

A vehicular driving force distribution control device that includes a hydraulic engaging device whose engagement state is controlled by hydraulic pressure, and that controls the distribution of driving force to a pair of left and right driving wheels via the hydraulic engaging device. And
An open / close state is controlled by an electrical command, and a hydraulic pressure holding valve that holds the hydraulic pressure in the hydraulic engagement device in the closed state;
A vehicle driving force distribution control device, comprising: a control device that outputs a command for controlling an open / close state of the hydraulic pressure holding valve in accordance with a running state of the vehicle.   The hydraulic engagement device includes a pair of clutches provided between an input member and an axle corresponding to each of the pair of drive wheels, and the control device includes a pair of drive wheels. The vehicular driving force distribution control device according to claim 1, wherein when the execution of the differential limiting control is determined, the hydraulic pressure holding valve corresponding to each of the pair of clutches is closed.   A planetary gear device is provided between the input member and the axle, and the hydraulic engagement device includes a brake provided between a non-rotating member and a carrier of the planetary gear device, and the control device The vehicle driving force distribution control device according to claim 1 or 2, wherein when the execution of torque distribution control of the pair of drive wheels is determined, the hydraulic pressure holding valve corresponding to the brake is closed. .   When the control device shifts from differential limiting control to torque distribution control of the pair of driving wheels, the control device immediately sets the hydraulic holding valve corresponding to the release side clutch among the hydraulic holding valves corresponding to the pair of clutches. 4. The vehicle driving force distribution control device according to claim 2 or 3, wherein the vehicle holding force distribution control device shifts the hydraulic pressure holding valve corresponding to the clutch on the engagement side to the open state at a predetermined change rate.

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