JP2009299779A - Control device for vehicular driving force distributing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for vehicular driving force distributing device, which is structured to achieve fail safe performance and which controls distribution of driving force generated by a driving force source to a pair of driving wheels in right and left. <P>SOLUTION: This control device for vehicular driving force distributing device comprises: engagement pressure sensors 52, 54 and 56 for detecting the engagement pressure of engaging devices C1, C2 and B; a wheel speed sensor 44 for detecting the rotating speed of each of a pair of rear wheels 30 in right and left; a speed sensor 50 for detecting the rotating speed of a clutch outer 72; and a fail determining means 42 for determining a fail based on a result of comparison between control request values relative to the engaging device C1, C2 and B and engagement pressure detection values detected by the engagement pressure sensors 52, 54 and 56 in response to the control request values and a result of comparison between the speed detection value of the clutch outer 72 detected by the speed sensor 50 and an average value of the speed detection values detected corresponding to the pair of rear wheels 30 in right and left by the wheel speed sensor 44. Practical fail safe can be thereby achieved. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device for a vehicle driving force distribution device that controls distribution of a driving force generated by a driving force source to a pair of left and right driving wheels, and more particularly to a fail-safe technique thereof.

  Drive that includes a plurality of engagement devices and controls the distribution of the drive force generated by the drive force source to the pair of left and right drive wheels by controlling the engagement state of the engagement devices according to the control request value A control device for a vehicle driving force distribution device that executes force distribution control is known. For example, the vehicle driving force distribution device described in Patent Document 1 is that. According to this technique, the driving force generated by the driving force source is distributed to the pair of left and right driving wheels by a differential device composed of a planetary gear device, while being coaxially disposed adjacent to the differential device. And a pair of clutches for selectively transmitting the output of the transmission mechanism to the carrier and the sun gear of the differential device. Thus, by slip-engaging one of the pair of clutches, the driving force transmitted through the transmission mechanism is transmitted to the sun gear or the carrier of the differential device, and the driving force is distributed. This makes it possible to suitably control the torque distribution transmitted to the pair of left and right drive wheels when turning the vehicle, and to limit the differential between the pair of left and right drive wheels as necessary. .

JP 2007-278379 A

  By the way, in general, a device provided in a driving force transmission device of a vehicle is required to have a fail-safe technique for ensuring a temporary operation of the driving force transmission device at the time of failure. Fail-safety was not realized for the driving force distribution device. For this reason, there has been a demand for the development of a technology that realizes the fail-safe for the vehicle driving force distribution device that controls the distribution of the driving force generated by the driving force source to the pair of left and right driving wheels.

  The present invention has been made in the background of the above circumstances, and the object of the present invention is to apply a driving force generated by a driving force source to a pair of left and right driving wheels configured to be fail-safe. An object of the present invention is to provide a control device for a vehicle driving force distribution device for controlling distribution.

  In order to achieve such an object, the gist of the present invention is that a plurality of engagement devices are provided, and the engagement state of these engagement devices is controlled in accordance with the control request value, so that the drive force source A control device for a vehicle driving force distribution device that executes driving force distribution control for controlling distribution of a generated driving force to a pair of left and right driving wheels, wherein the actual engagement pressure of each of the plurality of engagement devices An engagement pressure sensor that detects the actual rotation speed of each of the pair of left and right drive wheels, and an actual output member connected to at least one of the plurality of engagement devices. Comparison between the speed sensor for detecting the rotation speed, the control request value and the engagement pressure detection value actually detected by the engagement pressure sensor according to the control request value, and the speed sensor. Speed detection value and before A fail determination means for determining a failure of the driving force control device based on a comparison result with an average value of speed detection values actually detected corresponding to each of the pair of left and right driving wheels by a wheel speed sensor; And a driving force distribution control unit that stops the driving force distribution control by the driving force distribution device when a failure is determined by the fail determining unit.

  According to this configuration, the engagement pressure sensor that detects the actual engagement pressure of each of the plurality of engagement devices, the wheel speed sensor that detects the actual rotation speed of each of the pair of left and right drive wheels, and the plurality of the plurality of engagement devices A speed sensor for detecting an actual rotation speed of an intermediate output member connected to at least one of the engagement devices, and the engagement pressure sensor according to the control request value and the control request value. Of the detected engagement pressure, the detected speed value actually detected by the speed sensor, and the detected speed value actually detected by the wheel speed sensor corresponding to each of the pair of left and right drive wheels. Based on the comparison result with the average value, a failure determination unit that determines a failure of the driving force control device, and when the failure is determined by the failure determination unit, the driving force distribution device Since the driving force distribution control means for stopping the driving force distribution control is provided, a failure in the driving force distribution device can be suitably determined, and a practical fail safe can be realized. it can. That is, it is possible to provide a control device for a vehicular driving force distribution device that controls the distribution of a driving force generated by a driving force source to a pair of left and right driving wheels that is configured to be fail-safe.

  Here, preferably, a planetary gear device is provided between the input member of the driving force distribution device and a pair of left and right axles corresponding to the pair of left and right drive wheels, and the planetary gear device of the planetary gear device is used as the engagement device. A first clutch and a second clutch provided between a ring gear and the pair of left and right axles, respectively, and a brake provided between a non-rotating member and a carrier of the planetary gear device. . If it does in this way, in the driving force distribution device of a practical aspect, a suitable fail safe can be realized.

  Preferably, the fail determination means is (1) during the yaw control control by the driving force distribution device, by the engagement pressure sensor according to the control request value corresponding to the brake and the control request value. The brake engagement pressure detection value detected at the same time is equal to the control request value corresponding to the first clutch and the first clutch actually detected by the engagement pressure sensor according to the control request value. A control request value corresponding to the second clutch is equal to an engagement pressure detection value, and an engagement pressure detection value of the second clutch actually detected by the engagement pressure sensor in accordance with the control request value. An average of speed detection values that are equal to zero and that are actually detected by the speed sensor are actually detected by the wheel speed sensor corresponding to each of the pair of left and right drive wheels. (2) during the yaw control control by the driving force distribution device, the control request value corresponding to the brake and the engagement pressure sensor depending on the control request value. The brake engagement pressure detection value detected at the same time is equal to the control request value corresponding to the first clutch and the first clutch actually detected by the engagement pressure sensor according to the control request value. The engagement pressure detection value detected by the engagement pressure sensor corresponding to the control request value corresponding to the second clutch and the control request value corresponding to the control request value is equal to zero. An average of speed detection values that are equal to each other and that are actually detected by the speed sensor are actually detected by the wheel speed sensor corresponding to each of the pair of left and right drive wheels. (3) During the differential limiting control by the driving force distribution device, the control request value corresponding to the brake and the engagement pressure sensor according to the control request value The actually detected engagement pressure detection value of the brake is equal to zero, and the control request value corresponding to the first clutch and the actual detection by the engagement pressure sensor according to the control request value A control request value corresponding to the second clutch equal to an engagement pressure detection value of the first clutch, and an engagement pressure of the second clutch actually detected by the engagement pressure sensor according to the control request value The speed detection value that is equal to the detection value and that is actually detected by the speed sensor is equal to the average value of the speed detection value that is actually detected by the wheel speed sensor corresponding to each of the pair of left and right drive wheels. Shi (4) During non-control by the driving force distribution device, the engagement pressure sensor actually detects the control request value corresponding to the brake and the control request value. The brake engagement pressure detection value is equal to zero, the control request value corresponding to the first clutch, and the first clutch actually detected by the engagement pressure sensor according to the control request value. The engagement pressure detection value detected by the engagement pressure sensor corresponding to the control request value corresponding to the second clutch and the control request value corresponding to the control request value is equal to zero. A speed detection value actually detected by the speed sensor and an average value of speed detection values actually detected by the wheel speed sensor corresponding to the pair of left and right drive wheels, respectively, Equal It if that does not satisfy any of the conditions of the fourth condition to be satisfied, is to determine the failure of the driving force control device. In this way, a failure of the driving force distribution device can be determined in a practical manner.

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

  FIG. 1 illustrates the structure 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 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, a propeller shaft 24 as a driving force transmission shaft, a driving force distribution device 26, and a pair of left and right rear wheel axles 28l and 28r (hereinafter simply referred to as rear wheel axle 28 unless otherwise distinguished). It is transmitted to a pair of left and right rear wheels 30l and 30r (hereinafter simply referred to as rear wheels 30 unless otherwise distinguished) as drive wheels. Here, as shown in FIG. 1, in such a driving force transmission device 10, the rotating shaft of the rear wheel 30 and the rotating shaft of the propeller shaft 24 as driving wheels related to the driving force distribution by the driving force distributing device 26. 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 device 26, and the hydraulic circuit 32. A driving force distribution controller 34 is provided as a control device for controlling the hydraulic pressure and the like supplied from the hydraulic circuit 32 into the driving force distribution device 26 via an electromagnetic control valve (not shown) provided. 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 a command value (control request value) of the current supplied to the electromagnetic control valve provided in the hydraulic circuit 32, the current is supplied to the engagement element provided in the driving force distribution device 26. By controlling the hydraulic pressure, various controls such as differential limiting 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, fail determination means 42, and the like are functionally provided. These control functions will be described later with reference to FIGS.

  The power transmission device 10 includes wheel speed sensors 44l and 44r that detect actual rotational speeds of the pair of left and right rear wheels 30l and 30r (hereinafter, simply referred to as a wheel speed sensor 44 unless otherwise distinguished). A steering angle sensor 46 for detecting an actual steering angle of a steering wheel (not shown), an accelerator opening sensor 48 for detecting an actual accelerator opening corresponding to a depression amount of an accelerator pedal (not shown), and an intermediate output of the driving force distribution device 26 The speed sensor 50 that detects the actual rotation speed of the member, the first clutch engagement pressure sensor 52 that detects the actual engagement pressure of the first clutch C1 provided in the driving force distribution device 26, and the second clutch C2. Various sensors such as a second clutch engagement pressure sensor 54 that detects an actual engagement pressure, a brake engagement pressure detection sensor 56 that detects an actual engagement pressure of the brake B, and the like. And a signal representing the rotational speed of each of the pair of left and right rear wheels 30, a signal representing the steering angle of the steering wheel, a signal representing the accelerator opening, and an intermediate output of the driving force distribution device 26. A signal indicating the rotation speed of the member, a signal indicating the engagement pressure of each of the first clutch C1, the second clutch C2, and the brake B are input to the driving force distribution controller 34.

  FIG. 2 is a skeleton diagram illustrating the configuration of the driving force distribution device 26. As shown in FIG. 2, the driving force distribution device 26 includes, for example, a bevel gear 60 connected to an end of a propeller shaft 24 that is rotationally driven by the engine 12 via a central differential gear device 22; A bevel gear 62 meshing with the bevel gear 60 is provided, and a driving force is input through the pair of bevel gears 60 and 62. Further, a differential device 64 for distributing the driving force transmitted from the propeller shaft 24 via the bevel gears 60 and 62 to the left and right rear wheels 30l and 30r, and provided adjacent to the differential device 64. A transmission 66 arranged coaxially with the rear axles 28l and 28r, and a first clutch C1 which is an engagement element for selectively transmitting the output of the transmission 66 to the differential 64. And the second clutch C2.

  The differential device 64 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 which 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 68 in the case 68 of the differential device 64. The rotation of the propeller shaft 24 is decelerated by the bevel gears 60 and 62, and the first ring gear R1. To be communicated to. That is, in the present embodiment, the case 68 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 66 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 66, like the case 68. The sixth rotating 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 70 via the brake B. . The fourth rotation element RE4 is caused to function as an output member of the transmission 66. 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 64, 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 gear 64, 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 according to a control command from the driving force distribution controller 34. The engagement or release is performed by the hydraulic pressure output from the hydraulic circuit 32 controlled in this manner, and the transmission torque at the time of slip engagement is controlled by performing hydraulic control as necessary. The wheel speed sensors 44l and 44r detect actual rotational speeds of the pair of left and right rear wheel axles 28l and 28r corresponding to the pair of left and right rear wheels 30l and 30r, respectively. The speed sensor 50 detects the rotational speed of the clutch outer 72 common to the first clutch C1 and the second clutch C2 as the rotational speed of the intermediate output member of the driving force distribution device 26. In other words, the rotational speed of the second ring gear R2 of the transmission 66 is detected. The first clutch engagement pressure sensor 52 detects the actual engagement pressure of the first clutch C1. The second clutch engagement pressure sensor 54 detects the actual engagement pressure of the second clutch C2. The brake engagement pressure sensor 56 detects the actual engagement pressure of the brake B. The engagement pressure sensors 52, 54, and 56 detect mechanical pressing force of the clutch plates in the clutches C1 and C2 and the brake B as a multi-plate hydraulic friction engagement device. Alternatively, the hydraulic pressure supplied to the actuator that directly determines the engagement pressure may be detected.

  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. That is, the engagement control unit 40 functions as a driving force distribution control unit that outputs various control request values related to the driving force distribution control by the driving force distribution device 26. The driving force generated by the engine 12 is input as a driving force for rotationally driving the case 68 of the differential device 64 through 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 64 is provided integrally with the case 68, the driving force from the propeller shaft 24 is transmitted from the first ring gear R1 through the case 68 as an input member. Input to the differential unit 64. The engagement control means 40 controls 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 provided in the hydraulic circuit 32, for example. Thus, 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 device 64 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 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 64 of the driving force distribution 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 thus made, the vertical axis at the center is the rotation speed Ni of the first ring gear R1, which is the first rotation element RE1 rotated integrally with the case 68, 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 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 64 functions and the transmission device 66 is idled, so that the driving force is evenly distributed to the left and right rear wheels 30l, 30r. Accordingly, torque movement and differential limitation are not performed in the driving force distribution device 26, and the driving force distribution device 26 functions as a normal open differential. Further, when traveling straight, the differential device 64 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 66 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 right rear wheel 30r is accelerated by the differential device 64.

  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 66 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 rotation speed Nr of the right rear wheel 30r is decelerated by slip engagement, the left rear wheel 30l is accelerated by the differential device 64.

  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. That is, the driving force distribution device 26 functions as a vehicle differential limiting device that generates a differential limiting force for limiting the differential rotation of the rear wheel axle 28 corresponding to the pair of rear wheels 30. 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, If the determination by the vehicle speed determination means 36 is affirmative, preliminary control is performed to control the engagement state of the engagement element provided in the driving force distribution device 26 until the previous stage of executing the differential restriction 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.

  Returning to FIG. 1, the failure determination means 42 is a control request value (engagement pressure control value) output from the driving force distribution controller 34 corresponding to the first clutch C1, the second clutch C2, and the brake B. ) And the engagement pressure detection value actually detected by the engagement pressure sensors 52, 54, 56 according to the control request value, and the clutch outer 72 actually detected by the speed sensor 50. Based on the comparison result between the detected speed value and the average value of the detected speed values corresponding to the pair of left and right rear wheels 30l and 30r by the wheel speed sensors 44l and 44r, respectively. The failure of the device 26 is determined. Specifically, when none of the following four conditions, namely, conditions A-1, A-2, B, and C are satisfied, the driving force control device 26 fails (system failure). ). Note that “equal in the following conditions” includes substantially equal values in consideration of an error range and the like. For example, when the control request value is A, the actual measurement value B corresponding to the control request value A is the control value. To be equal to the required value A means that the actual measurement value B takes a value within the range of A ± ΔA in consideration of the error range ΔA.

[Condition A-1]
(A) During yaw control control by the driving force distribution device 26 (during yaw control control mode selection)
(B) The control request value corresponding to the brake B and the engagement pressure detection value of the brake B actually detected by the brake engagement pressure sensor 56 according to the control request value are equal (brake pressure control request Value = brake pressure sensor value)
(C) A control request value corresponding to the first clutch C1 and an engagement pressure detection value of the first clutch C1 that is actually detected by the first clutch engagement pressure sensor 52 in accordance with the control request value. Equal (first clutch pressure control request value = first clutch pressure sensor value)
(D) A control request value corresponding to the second clutch C2 and an engagement pressure detection value of the second clutch C2 that is actually detected by the second clutch engagement pressure sensor 54 in accordance with the control request value. Equally zero (second clutch pressure control request value = second clutch pressure sensor value = 0)
(E) The average speed detection value actually detected by the wheel speed sensor 44 corresponding to each of the pair of left and right rear wheels 30 is actually detected by the speed sensor 50. Larger than the value (speed sensor value> left and right wheel speed average)

[Condition A-2]
(A) During yaw control control by the driving force distribution device 26 (during yaw control control mode selection)
(B) The control request value corresponding to the brake B and the engagement pressure detection value of the brake B actually detected by the brake engagement pressure sensor 56 according to the control request value are equal (brake pressure control request Value = brake pressure sensor value)
(C) A control request value corresponding to the first clutch C1 and an engagement pressure detection value of the first clutch C1 that is actually detected by the first clutch engagement pressure sensor 52 in accordance with the control request value. Equally zero (first clutch pressure control request value = first clutch pressure sensor value = 0)
(D) A control request value corresponding to the second clutch C2 and an engagement pressure detection value of the second clutch C2 that is actually detected by the second clutch engagement pressure sensor 54 in accordance with the control request value. Equal (second clutch pressure control request value = second clutch pressure sensor value)
(E) The average speed detection value actually detected by the wheel speed sensor 44 corresponding to each of the pair of left and right rear wheels 30 is actually detected by the speed sensor 50. Larger than the value (speed sensor value> left and right wheel speed average)

[Condition B]
(A) During differential limiting control by the driving force distribution device 26 (while differential limiting control mode is selected)
(B) The control request value corresponding to the brake B and the engagement pressure detection value of the brake B actually detected by the brake engagement pressure sensor 56 according to the control request value are equal to zero (brake Required pressure control value = Brake pressure sensor value = 0)
(C) A control request value corresponding to the first clutch C1 and an engagement pressure detection value of the first clutch C1 that is actually detected by the first clutch engagement pressure sensor 52 in accordance with the control request value. Equal (first clutch pressure control request value = first clutch pressure sensor value)
(D) A control request value corresponding to the second clutch C2 and an engagement pressure detection value of the second clutch C2 that is actually detected by the second clutch engagement pressure sensor 54 in accordance with the control request value. Equal (second clutch pressure control request value = second clutch pressure sensor value)
(E) The average of the speed detection value of the clutch outer 72 actually detected by the speed sensor 50 and the speed detection value actually detected by the wheel speed sensor 44 corresponding to each of the pair of left and right rear wheels 30 Value is equal (speed sensor value = average of left and right wheel speeds)

[Condition C]
(A) Control by the driving force distribution device 26 is not performed (during non-control mode selection)
(B) The control request value corresponding to the brake B and the engagement pressure detection value of the brake B actually detected by the brake engagement pressure sensor 56 according to the control request value are equal to zero (brake Required pressure control value = Brake pressure sensor value = 0)
(C) A control request value corresponding to the first clutch C1 and an engagement pressure detection value of the first clutch C1 that is actually detected by the first clutch engagement pressure sensor 52 in accordance with the control request value. Equally zero (first clutch pressure control request value = first clutch pressure sensor value = 0)
(D) A control request value corresponding to the second clutch C2 and an engagement pressure detection value of the second clutch C2 that is actually detected by the second clutch engagement pressure sensor 54 in accordance with the control request value. Equally zero (second clutch pressure control request value = second clutch pressure sensor value = 0)
(E) The average of the speed detection value of the clutch outer 72 actually detected by the speed sensor 50 and the speed detection value actually detected by the wheel speed sensor 44 corresponding to each of the pair of left and right rear wheels 30 Value is equal (speed sensor value = average of left and right wheel speeds)

  The engagement control unit 40 stops the driving force distribution control by the driving force distribution device 26 when the failure determination unit 42 determines a failure. That is, the non-control mode is set to stop the actuator related to the driving force distribution device 26. In other words, the engagement pressure control of the first clutch C1, the second clutch C2, and the brake B is not executed, and the operation of these engagement devices is stopped. Thus, by stopping the driving force distribution control by the driving force distribution device 26, the driving force distribution device 26 functions as a normal open differential as shown in FIG. The vehicle is guaranteed to run even during a failure.

  FIG. 8 is a flowchart for explaining a main part of the fail-safe 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 or not the condition A-1 is satisfied. If the determination in S1 is affirmative, the routine is terminated accordingly. If the determination in S1 is negative, it is determined in S2 whether or not the condition A-2 is satisfied. The If the determination in S2 is affirmative, the routine is terminated accordingly. If the determination in S2 is negative, it is determined in S3 whether or not the condition B is satisfied. If the determination in S3 is affirmative, the routine is terminated accordingly. If the determination in S3 is negative, it is determined in S4 whether the condition C is satisfied. If the determination at S4 is affirmative, the routine is terminated accordingly. If the determination at S4 is negative, a failure (system failure) of the driving force distribution device 26 is determined at S5. Is done. Next, in S6 corresponding to the operation of the engagement control means 40, after the operation of the actuator related to the driving force distribution device 26 is stopped, this routine is ended. In the above control, S1 to S5 correspond to the operation of the fail determination means 42.

  As described above, according to the present embodiment, the engagement pressure sensors 52, 54, and 56 that detect the actual engagement pressures of the first clutch C1, the second clutch C2, and the brake B, and the pair of left and right rears. A wheel speed sensor 44 that detects the actual rotation speed of each of the wheels 30 and a speed sensor 50 that detects the actual rotation speed of the clutch outer 72 serving as an intermediate output member connected to the first clutch C1 and the second clutch C2. And a control request value corresponding to the first clutch C1, the second clutch C2, and the brake B, and an engagement pressure detection value that is actually detected by the engagement pressure sensors 52, 54, and 56 according to the control request value. And the speed detection value of the clutch outer 72 actually detected by the speed sensor 50 and the pair of left and right rear wheels 30 by the wheel speed sensor 44, respectively. Based on the comparison result with the average value of the speed detection values actually detected in response, the failure determination means 42 (S1 to S5) for determining the failure of the driving force control device 26 and the failure determination means 42 Since it is provided with the engagement control means 40 (S6) as the driving force distribution control means for stopping the driving force distribution control by the driving force distribution device 26 when the failure is determined. A failure in the driving force distribution device 26 can be suitably determined, and a practical fail safe can be realized. That is, it is possible to provide a control device for the vehicle driving force distribution device 26 that controls the distribution of the driving force generated by the engine 12 to the pair of left and right rear wheels 30 that is configured to be fail-safe.

  Further, a transmission 66 comprising a planetary gear device is provided between a case 68 as an input member of the driving force distribution device 26 and a pair of left and right rear axles 28 corresponding to the pair of left and right rear wheels 30. As a combined device, a first clutch C1 and a second clutch C2 provided between a ring gear R2 of the transmission 66 and the pair of left and right rear axles 28l, 28r, a non-rotating member 70, and the transmission 66, respectively. Since the brake B provided between the carrier CA2 and the carrier CA2 is provided, a suitable failsafe can be realized in the driving force distribution device 26 in a practical aspect.

  Further, the fail determination means 42 is actually detected by the brake engagement pressure sensor 56 according to the control request value corresponding to the brake B and the control request value during the yaw control control by the driving force distribution device 26. The brake B engagement pressure detection value is equal, the control request value corresponding to the first clutch C1 and the actual detection by the first clutch engagement pressure sensor 52 according to the control request value. The engagement pressure detection value of the first clutch C1 is equal, and the control request value corresponding to the second clutch C2 and the second clutch engagement pressure sensor 54 that is actually detected according to the control request value. The engagement pressure detection value of the two clutch C2 is equal to zero, and the speed detection value actually detected by the speed sensor 50 is detected by the wheel speed sensor 44. In condition A-1, which satisfies that the speed detection value actually detected corresponding to each of the pair of rear wheels 30 is larger than the average value, during the yaw control control by the driving force distribution device 26, the brake B The corresponding control request value is equal to the brake B engagement pressure detection value actually detected by the brake engagement pressure sensor 56 in accordance with the control request value, and the control request value corresponding to the first clutch C1. And the detected engagement pressure value of the first clutch C1 actually detected by the first clutch engagement pressure sensor 52 in accordance with the control request value is equal to zero, and the control corresponding to the second clutch C2 The requested value and the engagement pressure detection value of the second clutch C2 actually detected by the second clutch engagement pressure sensor 54 according to the control request value are equal, and the speed sensor Condition A− where it is established that the detected speed value actually detected by 50 is larger than the average value of the detected speed values actually detected by the wheel speed sensor 44 corresponding to each of the pair of left and right rear wheels 30. 2. During the differential limiting control by the driving force distribution device 26, the control request value corresponding to the brake B and the brake B actually detected by the brake engagement pressure sensor 56 according to the control request value The first clutch that is actually detected by the first clutch engagement pressure sensor 52 in accordance with the control request value corresponding to the first clutch C1 and the control request value corresponding to the first clutch C1. The detected engagement pressure value of C1 is equal and is actually detected by the second clutch engagement pressure sensor 54 in accordance with the control request value corresponding to the second clutch C2 and the control request value. The engagement pressure detection value of the second clutch C2 is equal, and the speed detection value actually detected by the speed sensor 50 and the wheel speed sensor 44 are actually corresponding to the left and right rear wheels 30 respectively. The condition B in which the average value of the detected speed detection values is equal, and the non-control by the driving force distribution device 26, the control request value corresponding to the brake B and the brake according to the control request value The engagement pressure detection value of the brake B actually detected by the engagement pressure sensor 56 is equally zero, and the first clutch according to the control request value corresponding to the first clutch C1 and the control request value. The engagement pressure detection value of the first clutch C1 actually detected by the engagement pressure sensor 52 is equal to zero, and the control request value corresponding to the second clutch C2 and the control request value are the same. The detected value of the second clutch C2 actually detected by the second clutch engaging pressure sensor 54 is equal to zero, and the speed detected value actually detected by the speed sensor 50 When none of the conditions C in which the average value of the speed detection values actually detected corresponding to the pair of left and right rear wheels 30 by the wheel speed sensor 44 is equal is satisfied, Since the failure of the driving force control device 26 is determined, the failure of the driving force distribution device 26 can be determined in a practical manner.

  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, the present invention is applied to the driving force distribution device 26 that controls the distribution of the driving force to the rear wheels 30l and 30r corresponding to the pair of left and right rear wheels 30l and 30r. However, the present invention is not limited to this. For example, the present invention may be applied to a driving force distribution 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 It is a skeleton diagram explaining the structure of the driving force transmission apparatus of the front-and-rear wheel drive vehicle based on the front engine front wheel drive provided with the driving force distribution apparatus to which this invention is applied suitably. FIG. 2 is a skeleton diagram illustrating a configuration of a driving force distribution 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 device of FIG. 2 is not controlled. FIG. 3 is a collinear diagram showing the number of rotations of each rotating element during the left and right wheel torque control of the driving force distribution device of FIG. 2. FIG. 3 is a collinear diagram showing the number of rotations of each rotating element during the left and right wheel torque control of the driving force distribution 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 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 driving force transmission device of FIG. 1. It is a flowchart explaining the principal part of the fail safe control by the power distribution controller with which the driving force transmission apparatus of FIG. 1 was equipped.

Explanation of symbols

12: Engine (drive power source)
26: Vehicle driving force distribution device 28: Rear wheel axle 30: Rear wheel (drive wheel)
40: Engagement control means (driving force distribution control means)
42: Fail determination means 44: Wheel speed sensor 50: Speed sensor 52: First clutch engagement pressure sensor 54: Second clutch engagement pressure sensor 56: Brake engagement pressure sensor 66: Transmission (planetary gear device)
68: Case (input member)
70: Non-rotating member 72: Clutch outer (intermediate output member)
B: Brake (engagement device)
CA2: second carrier C1: first clutch (engagement device)
C2: Second clutch (engagement device)
R2: Second ring gear

Claims (3)

Drive that includes a plurality of engagement devices and controls the distribution of the drive force generated by the drive force source to the pair of left and right drive wheels by controlling the engagement state of the engagement devices according to the control request value A control device for a vehicle driving force distribution device that executes force distribution control,
An engagement pressure sensor for detecting an actual engagement pressure of each of the plurality of engagement devices;
A wheel speed sensor for detecting an actual rotational speed of each of the pair of left and right drive wheels;
A speed sensor for detecting an actual rotation speed of an intermediate output member connected to at least one of the plurality of engagement devices;
The comparison result between the control request value and the engagement pressure detection value actually detected by the engagement pressure sensor according to the control request value, and the speed detection value actually detected by the speed sensor and the wheel speed Fail determination means for determining a failure of the driving force control device based on a comparison result with an average value of speed detection values actually detected by the sensor corresponding to each of the pair of left and right drive wheels;
And a driving force distribution control means for stopping the driving force distribution control by the driving force distribution device when a failure is determined by the fail determining means. Distribution unit control unit. A planetary gear device is provided between the input member of the driving force distribution device and a pair of left and right axles corresponding to the pair of left and right driving wheels,
A first clutch and a second clutch respectively provided between the ring gear of the planetary gear device and the pair of left and right axles as the engagement device;
The control device for a vehicle driving force distribution device according to claim 1, further comprising: a brake provided between a non-rotating member and a carrier of the planetary gear device. The fail determination means includes
During yaw control control by the driving force distribution device,
The control request value corresponding to the brake is equal to the brake engagement pressure detection value actually detected by the engagement pressure sensor according to the control request value,
The control request value corresponding to the first clutch and the engagement pressure detection value of the first clutch actually detected by the engagement pressure sensor according to the control request value are equal,
The control request value corresponding to the second clutch and the engagement pressure detection value of the second clutch actually detected by the engagement pressure sensor according to the control request value are equal to zero,
In addition, it is established that a speed detection value actually detected by the speed sensor is larger than an average value of speed detection values actually detected by the wheel speed sensor corresponding to each of the pair of left and right drive wheels. Conditions,
During yaw control control by the driving force distribution device,
The control request value corresponding to the brake is equal to the brake engagement pressure detection value actually detected by the engagement pressure sensor according to the control request value,
The control request value corresponding to the first clutch and the engagement pressure detection value of the first clutch actually detected by the engagement pressure sensor according to the control request value are equal to zero,
The control request value corresponding to the second clutch and the engagement pressure detection value of the second clutch actually detected by the engagement pressure sensor according to the control request value are equal,
In addition, it is established that a speed detection value actually detected by the speed sensor is larger than an average value of speed detection values actually detected by the wheel speed sensor corresponding to each of the pair of left and right drive wheels. Conditions,
During differential limiting control by the driving force distribution device,
The control request value corresponding to the brake and the engagement pressure detection value of the brake actually detected by the engagement pressure sensor according to the control request value are equal to zero,
The control request value corresponding to the first clutch and the engagement pressure detection value of the first clutch actually detected by the engagement pressure sensor according to the control request value are equal,
The control request value corresponding to the second clutch and the engagement pressure detection value of the second clutch actually detected by the engagement pressure sensor according to the control request value are equal,
In addition, it is established that the speed detection value actually detected by the speed sensor is equal to the average value of the speed detection values actually detected by the wheel speed sensor corresponding to each of the pair of left and right drive wheels. Conditions,
During non-control by the driving force distribution device,
The control request value corresponding to the brake and the engagement pressure detection value of the brake actually detected by the engagement pressure sensor according to the control request value are equal to zero,
The control request value corresponding to the first clutch and the engagement pressure detection value of the first clutch actually detected by the engagement pressure sensor in accordance with the control request value are equal to zero,
The control request value corresponding to the second clutch and the engagement pressure detection value of the second clutch actually detected by the engagement pressure sensor according to the control request value are equal to zero,
Further, it is established that the speed detection value actually detected by the speed sensor is equal to the average value of the speed detection values actually detected by the wheel speed sensor corresponding to each of the pair of left and right drive wheels. The control device for a vehicle driving force distribution device according to claim 2, wherein a failure of the driving force control device is determined when none of the conditions is satisfied.

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