JP2008114674A - Driving force distribution device for four-wheel drive vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decrease cost, size, and weight, by using an oil pressure source of a friction clutch hydraulic control system to a transmission switching mechanism. <P>SOLUTION: A driving force distribution device for a four-wheel drive vehicle comprises a friction clutch 26 selectively transmitting torque from a main output shaft to a sub output shaft, and a sub transmission switching power from an input shaft into at least two stages of high-speed and low-speed and transmitting that to the main output shaft. The friction clutch hydraulic system 32 controls changes pressing force of the friction clutch 26 according to the supplied oil pressure of the oil pressure source equipped with a motor 71 and a hydraulic pump 72 to control transmitting torque. A sub transmission hydraulic control system 74A of the sub transmission energizes solenoid switch valves 82, 84, supplies the supplied oil pressure from the hydraulic pump 72 to one of a cylinder chamber of a waiting mechanism 75, and shift-moving a shift fork 56 by a shift rod 58. The waiting mechanism 75 is integrally equipped with a piston/cylinder mechanism driving the shift rod 58. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a full-time driving force distribution device for a four-wheel drive vehicle that changes a sub-transmission mechanism and changes the pressing force of a friction clutch that transmits power to a front wheel, and particularly uses a hydraulic power source of the friction clutch. The present invention relates to a driving force distribution device for a four-wheel drive vehicle that switches an auxiliary transmission.

  Conventionally, a full-time driving force distribution device for a four-wheel drive vehicle includes a friction clutch that continuously changes torque transmitted from the rear wheel output shaft to the front wheel output shaft in accordance with the traveling state of the vehicle, and power from the input shaft. Is provided with a sub-transmission for switching to at least two stages of high speed and low speed and transmitting it to the rear wheel output shaft.

  The actuator of the friction clutch is a hydraulic actuator based on a piston / cylinder mechanism. The hydraulic pressure supplied from a hydraulic source composed of a motor and a hydraulic pump is supplied to the cylinder chamber, and the hydraulic pressure supplied from the hydraulic pump to the cylinder is controlled by motor rotation control. Therefore, a hydraulic control system is used that changes the pressing force of the friction clutch by the piston and controls the torque transmitted to the front wheels.

On the other hand, the auxiliary transmission uses a dedicated electric actuator composed of a motor and a speed reducer, and transmits the power input from the main transmission to at least two stages of high speed H and low speed L and transmits it to the rear wheel output shaft. (Patent Document 1).
JP 2001-206092 A

  However, in the conventional driving force distribution device for a four-wheel drive vehicle provided with the friction clutch and the auxiliary transmission, a hydraulic actuator driven by a hydraulic control system is provided for controlling the friction clutch, and the auxiliary transmission is provided. Since a dedicated electric actuator is provided for switching between the two, two sets of actuators are required, which complicates the structure and increases the cost, and increases the size and weight of the apparatus.

The present invention relates to a driving force distribution device for a four-wheel drive vehicle that uses a hydraulic power source of a friction clutch hydraulic control system as a hydraulic power source of a switching control actuator of a sub-transmission to reduce cost, size, and weight. The purpose is to provide.

  According to the present invention, a friction clutch that selectively transmits torque from a main output shaft (rear wheel output shaft) to a secondary output shaft (front wheel output shaft) and power from the input shaft are switched to at least two stages of high speed and low speed. A driving force distribution device for a four-wheel drive vehicle including a sub-transmission that transmits to a main output shaft is an object.

In such a four-wheel drive vehicle driving force distribution device, the present invention provides:
A friction clutch hydraulic control system that controls the transmission torque by changing the pressing force of the friction clutch according to the hydraulic pressure supplied by a hydraulic source including a motor and a hydraulic pump;
A sub-transmission hydraulic control system that switches and controls the sub-transmission by the supply hydraulic pressure of the hydraulic source;
It is provided with.

  Here, the friction clutch hydraulic control system supplies oil to the first cylinder that presses the friction clutch, the first cylinder that slidably accommodates the first piston, and the first cylinder during forward rotation, and reverse rotation. Sometimes a hydraulic pump that drains oil from the first cylinder, a pressure sensor that detects the hydraulic pressure generated by the hydraulic pump, a motor that drives the hydraulic pump forward and backward, and a detected hydraulic pressure of the pressure sensor to be a predetermined set hydraulic pressure. And a first controller for controlling forward / reverse driving of the motor to control the pressing force of the friction clutch to a predetermined value.

  The hydraulic control system for the auxiliary transmission includes a second piston that moves a shift fork attached to a shift rod to a switching position, a second cylinder that slidably houses the second piston, and both sides of the second piston. Provided for each cylinder chamber that is formed, a pair of electromagnetic switching valves that supply oil to the cylinder chamber when energized and discharge oil from the cylinder chamber when de-energized, and detect when the shift fork reaches the switching position When moving the position fork and shift fork to one of the switching positions, control the forward / reverse rotation of the motor and supply oil of a predetermined hydraulic pressure from the hydraulic pump. Energize one side to supply oil to the corresponding cylinder chamber of the second piston, and stop energizing the electromagnetic switching valve when the position sensor detects that the shift fork has reached the switching position. And a 2 controller.

  The hydraulic control system for the auxiliary transmission includes a waiting mechanism between the shift rod and the shift fork that compresses the spring against the movement of the shift rod to the switching position and biases the shift fork in the switching direction. In the driving force distribution device for a driving vehicle according to the present invention, the second piston, the second cylinder, and the waiting mechanism are integrated.

The waiting mechanism as this integrated structure is
A pair of slide rings slidably inserted into the shift rod;
A spring disposed between a pair of slide rings;
A shift sleeve slidably disposed on the outside of the pair of slide rings;
A pair of first stopper rings that are fitted to the shift rod and lock the inner peripheral end surfaces of the pair of slide rings;
A pair of second stopper rings that are fitted to the inner peripheral surface of the shaft hole of the shift sleeve and engage the outer peripheral side end surface portions of the pair of slide rings;
A piston portion constituting a second piston integrally formed by projecting annularly on the outer periphery of the shift sleeve;
A cylinder constituting a second cylinder slidably storing a shift sleeve having a piston portion;
A pair of locks that are located in each of the cylinder chambers on both sides partitioned by the piston part, fitted and locked to the shift sleeve by urging by a spring member, and moved as a piston when hydraulic pressure is supplied to unlock the shift sleeve idea,
Is provided.

  According to the present invention, by switching the auxiliary transmission switching mechanism using the hydraulic power source of the friction clutch hydraulic control system, it is possible to reduce the cost and weight of the device compared with the case where an expensive and heavy dedicated actuator is provided. Can be provided.

  In addition, since the actuator for switching the auxiliary transmission having a large size is not necessary, restrictions on mounting the device on the vehicle are reduced, and the actuator can be mounted on many different types of vehicles.

  In addition, the current consumption can be reduced by using a normally closed electromagnetic switching valve that only needs to be energized when switching the auxiliary transmission as the electromagnetic switching valve.

  Furthermore, even if the same hydraulic pressure source is used for the friction clutch hydraulic control system and the auxiliary transmission switching mechanism, the auxiliary transmission is normally switched while the vehicle is stopped, while the friction clutch is controlled while the vehicle is running. Therefore, even if the same hydraulic power source is used, in principle, control is not duplicated, and adverse effects due to competing hydraulic sources can be prevented.

  In addition, in the vehicle stop state in which the auxiliary transmission is switched, a predetermined hydraulic pressure necessary for switching is generated from the hydraulic source, but the switching hydraulic pressure remains when the vehicle starts running after the auxiliary transmission is switched. As a result, the response time of the clutch control can be shortened.

  Also, even if the hydraulic pressure required for switching the sub-transmission increases and the friction clutch is engaged by pressing force, it is in the vehicle stop state, so there is no effect on the vehicle and the hydraulic pressure source is the same There is no control interference.

  In addition, since the sub-transmission switching mechanism is constituted by a meshing clutch gear, if the gear phase does not match, it will stop in the middle of switching, but a waiting mechanism should be provided between the shift rod and the shift fork. Even when the phase of the clutch gear does not match, the spring of the waiting mechanism is compressed by the switching operation to complete the switching operation, and then the shift fork is moved by the spring force when the gear phase is matched and the switching is performed. Can be completed.

Furthermore, by integrating the piston and cylinder of the auxiliary transmission switching mechanism into the waiting mechanism, it is possible to reduce the cost and weight as compared with the case where they are provided separately.

  FIG. 1 is a sectional view showing an embodiment of a driving force distribution device for a four-wheel drive vehicle according to the present invention. In FIG. 1, the driving force distribution device for a four-wheel drive vehicle of this embodiment has a case 10, and an input shaft 12 for inputting power from the engine via an automatic transmission or a manual transmission is provided on the left side of the case 10. The input shaft 12 is connected to a rear wheel output shaft 24 as a main output shaft arranged coaxially via the auxiliary transmission mechanism 14.

  The auxiliary transmission mechanism 14 is a planetary gear mechanism including a sun gear 16, a planetary gear 18 provided in the carrier case 20, and a ring gear 22. A clutch gear 54 is provided integrally with the carrier case 20, and a shift operation can be performed corresponding to this. A shift gear 52 is arranged. The auxiliary transmission mechanism 14 switches between the H position and the L position.

  When the shift gear 52 is at the illustrated position, it is in the H position, and the sun gear 16 is directly connected to the rear wheel output shaft 24. The position where the shift gear 52 meshes with the clutch gear 54 is the L position, the ring gear 22 is fixed, and the input rotation of the sun gear 16 is rotated as the rotation of the carrier case 20 with the planetary gear 18 from the clutch gear 54 via the shift gear 52. This is transmitted to the rear wheel output shaft 24.

  A friction clutch 26 is provided coaxially with the rear wheel output shaft 24. The friction clutch 26 has a clutch hub 44 fixed to the rear wheel output shaft 24, and a clutch drum 46 is connected to a sprocket gear 25 provided to be rotatable with respect to the rear wheel output shaft 24. In parallel with the rear wheel output shaft 24, a front wheel output shaft 30 as a secondary output shaft for extracting power to the opposite side is provided in the case 10, and a sprocket gear 31 is formed integrally with the front wheel output shaft 30 for friction. A chain belt 28 is hung and connected to the sprocket gear 25 on the clutch 26 side.

  In such a four-wheel drive vehicle driving force distribution device, the multi-plate clutch 48 provided between the clutch hub 44 and the clutch drum 46 of the friction clutch 26 is disconnected during two-wheel drive, and the input shaft 12 rotates. Is transmitted to the rear wheel output shaft 24 via the auxiliary transmission mechanism 14. During four-wheel drive, the friction clutch 26 is in a connected state, and the power from the input shaft 12 is transmitted through the rear wheel output shaft 24, the friction clutch 26, the sprocket gear 25, the chain belt 28, and the sprocket gear 31 to the front wheel output shaft. 30 is also transmitted.

  A friction clutch hydraulic control system 32 is provided for the friction clutch 26. The friction clutch hydraulic control system 32 slidably accommodates a piston 36 as a first piston in a cylinder 34 as a first cylinder formed integrally with the case 11, and a hydraulic pressure source is provided in a cylinder chamber 38. The hydraulic pressure is supplied from a hydraulic pump 72 driven by a motor 71 provided in the unit 70, and the pressing member 40 is moved against the return spring 49 by the piston 36 to press the multi-plate clutch 38, and according to the supplied hydraulic pressure. The transmission torque is controlled by changing the pressing force.

  An auxiliary transmission hydraulic control system 74 is provided for the auxiliary transmission 14. The hydraulic actuator of the auxiliary transmission hydraulic control system 74 is mounted on the shift rod 58. In this embodiment, the cylinder / piston mechanism for moving the shift rod 58 by the hydraulic pressure supplied from the hydraulic pump 72 and the waiting mechanism. Is an integrated structure.

  FIG. 2 is an explanatory view showing the friction clutch hydraulic control system and the auxiliary transmission hydraulic control system according to the present embodiment. In FIG. 2, the friction clutch hydraulic control system 32 uses a hydraulic pump 72 driven by a motor 71 as a hydraulic source, and a piston 36 is slidable in a cylinder 34 formed integrally with the case 11 with respect to the friction clutch 26. It is stored in. The piston 36 is fitted with seal rings 37 a and 37 b to seal the cylinder chamber 38.

  The port of the hydraulic pump 72 is directly connected to the cylinder chamber 38 of the cylinder 34 by a pipe 73. A pressure sensor 85 that detects the hydraulic pressure supplied to the cylinder chamber 38 is provided for the pipe 73.

  The friction clutch control system 32 is controlled by a first controller 78 provided in the control unit 76. A hydraulic pressure detection signal from the pressure sensor 85 and a vehicle state detection signal from a sensor provided in the vehicle state detection unit 81 are input to the control unit 76.

  The first controller 78 performs forward / reverse drive control of the motor 71 to control the torque transmitted to the front wheels by the friction clutch 48 necessary for full-time four-wheel drive in the running state of the vehicle. That is, the supply hydraulic pressure to the cylinder chamber 38 is controlled by forward / reverse drive control of the motor 71, the piston 36 is pressed by this supply hydraulic pressure, the pressing force of the multi-plate clutch 48 by the pressing member 40 is controlled, and the pressing force is controlled. The torque transmitted to the front wheel side by the friction clutch 26 is controlled.

  Such a friction clutch hydraulic control system 32 is the same as the conventional friction clutch control.

  In addition to this, in the present embodiment, an auxiliary transmission hydraulic control system 74A is further provided. The auxiliary transmission hydraulic control system 74 </ b> A includes a waiting mechanism 75 that is integrally provided with a piston cylinder mechanism that is hydraulically driven by the shift rod 58.

  FIG. 3 is a cross-sectional view of a waiting mechanism integrally provided with the piston / cylinder mechanism of this embodiment. In FIG. 3, the waiting mechanism 75 is disposed on the shift rod 58 via a coil spring 104 between the pair of slide rings 100 and 102, and stopper rings 106 and 108 are fitted to the shift rod 58 outside the slide rings 100 and 102. The outer sides of the slide rings 100 and 102 are locked and positioned.

  A shift sleeve 98 is slidably inserted outside the slide rings 100 and 102. Stopper rings 110 and 112 are fitted in the vicinity of the end face on the inner peripheral side of the shift sleeve 98, and the end face portions are locked to the inner peripheral side of the slide rings 100 and 102 disposed on the inner side.

  The shift sleeve 98 is integrally provided with a piston portion 114 as a second piston, and the piston portion 114 is slidably disposed in a cylinder 116 as a second cylinder formed in the case 100. A cylinder chamber 118 is formed on the partitioned left side, and a cylinder chamber 120 is formed on the right side. A port Q1 is provided for the cylinder chamber 118, and a port Q2 is provided for the cylinder chamber 120.

  A lock pin 122 is slidably provided at a lower position corresponding to the cylinder chamber 118 in a direction perpendicular to the shift rod 58, and the lock pin 122 is urged by contact with a leaf spring 126 provided at the outer end portion. The tip of the lock pin 122 is fitted into the lock groove 130 provided on the outer periphery at the position of the shift sleeve 98 shown in the figure, and the shift sleeve 98 is positioned and held.

  A lock pin 124 is slidable in a direction perpendicular to the shift rod 58 at a lower position corresponding to the right cylinder chamber 120, and is axially moved by a leaf spring 128 arranged outside the lock pin 124. Is being energized. A lock groove 132 is formed in the cylinder sleeve 98 corresponding to the lock pin 124.

  In the position of the shift sleeve 98 shown in the figure, the lock pin 124 is located at a position away from the lock groove 132 on the right side. When the lock pin 122 is unlocked and the shift sleeve 98 moves to the right, the lock groove When 132 moves to the position of the lock pin 124, the lock pin 124 is fitted, and the shift sleeve 98 is positioned and held.

  Referring to FIG. 2 again, electromagnetic switching valves 82 and 84 are provided for the ports Q1 and Q2 of the waiting mechanism 75 having the structure of FIG. The electromagnetic switching valves 82 and 84 have two switching devices 82a and 82b, branch the piping 73 from the hydraulic pump 72 and connect it to the port P1, and connect the port Q1 of the waiting mechanism 75 to the port P2. Each port T communicates with the tank.

  The electromagnetic switching valve 82 is in the illustrated switching position 82a when the solenoid is not energized. In this state, the port Q1 of the waiting mechanism 75 is connected to the tank port T, so that the hydraulic pressure in the cylinder chamber 118 of FIG. (Tank pressure). The electromagnetic switching valve 84 is the same as the electromagnetic switching valve 82, has switching positions 84a and 84b, is in the switch 84a when the solenoid is not energized, and communicates the port Q2 of the waiting mechanism 75 from the port P4 to the tank port T. The hydraulic pressure in the cylinder chamber 120 in FIG. 3 is zero.

  The electromagnetic switching valves 82 and 84 are controlled by a second controller 80 provided in the control unit 76. The second controller 80 controls the electromagnetic switching valves 82 and 84 based on the shift operation of the auxiliary transmission when the vehicle is stopped.

  A shift fork 56 is fixed to the shift rod 58. Position switches 86 and 88 are provided for a switch cam 90 provided on the shift fork 56, and detection signals from the position switches 86 and 88 are input to the control unit 76. Yes. Check grooves 94 and 96 are formed on the left side of the shift rod 58, and are fitted and held in the check groove 94 at a switching position where the illustrated shift rod 58 is set to the H position.

  Shift control of the auxiliary transmission hydraulic control system 74a by the second controller 80 provided in the control unit 76 is as follows. The sub-transmission switching operation is performed when the vehicle is stopped. When the vehicle stop state is detected by a detection signal from the vehicle state detection unit 81, the second controller 80 drives the motor 71 at a predetermined rotational speed so that the motor 71 generates a predetermined hydraulic pressure necessary for the shift operation of the sub-transmission. .

  In this state, for example, if a shift operation for switching from the H position to the L position shown in the figure is performed by an operation of a shift button (not shown), the second controller 80 recognizes this shift operation and energizes the electromagnetic switching valve 82. Then, the switching position 82a is switched to the switching position 82b on the right side.

  Therefore, the hydraulic pressure supplied from the hydraulic pump 72 is supplied from the port P1 of the electromagnetic switching valve 82 to the port Q1 of the output waiting mechanism 75 from the port P2 through the path of the switching position 82b.

  The operation of the waiting mechanism 75 when the electromagnetic switching valve 82 of the auxiliary transmission hydraulic control system 74a shown in FIG. 2 is energized will be described with reference to FIGS. FIG. 4A shows an initial state in which the electromagnetic switching valves 82 and 84 in FIG. 2 are in a non-energized state. The ports Q1 and Q2 are communicated with the tank port T, the hydraulic pressure is zero, and the lock pin 122 is shifted. It fits into the lock groove 130 of the sleeve 98 and stops its movement.

  2 is energized, and when the hydraulic pressure is supplied to the port Q1 as indicated by the arrow by switching to the switching position 82b, the lock pin 122 receives the hydraulic pressure of the port Q1 and the plate The shift sleeve 98 is slidable by being pushed out against the spring 126 and coming out of the lock groove 130. FIG. 4B shows this state.

  Therefore, the shift sleeve 98 starts to move in the right direction by the hydraulic pressure applied from the port Q1 to the cylinder chamber on the right side of the piston portion 114. If the phase of the shift gear (not shown) on the shift fork 56 side of FIG. 2 attached to the shift rod 58 is not matched at this time, the shift rod 58 cannot move, and only the shift sleeve 98 starts to move to the right. As a result, the slide ring 100 also receives the locking by the stopper ring 110 and moves to the right.

  On the other hand, the slide ring 102 provided at the right end does not move because it is locked to the shift rod 58 by the stopper ring 108, and the coil spring 104 is compressed by the movement of the slide ring 110 accompanying the movement of the shift sleeve 98.

  FIG. 5C shows a state in which the shift sleeve 98 has moved from the H position to the L position. When the shift sleeve 98 reaches a position where it can be shifted to the L position, the lock groove 132 of the shift sleeve 98 reaches the position of the lock pin 124. The pin 124 is pushed by the leaf spring 126 and fits into the lock groove 132, and the shift sleeve 98 is positioned and held.

  In the state of FIG. 5C, the coil spring 104 of the waiting mechanism 75 is compressed, and the reaction force due to the compression of the coil spring 104 shifts the shift rod 58 via the slide ring 102 and the stopper ring 112. The waiting state is energized in the right direction.

  Thereafter, when the vehicle starts running and the gear phases coincide with each other, the shift rod 58 moves to the right side by the force of the coil spring 104 as shown in FIG. 5D, and the shift fork 56 shown in FIG. To complete the shift switching.

  The movement of the shift fork 56 to the L position is detected when the switch knob of the position switch 88 is pushed up by the switch cam 90, the position switch 88 is turned on, and the second controller receives the detection of switching to the L position by the position switch 88. 80 stops energization of the electromagnetic switching valve 82 and discharges the hydraulic pressure supplied to the waiting mechanism 75 to the tank port T to zero.

  As shown in FIG. 5D, when the shift rod 58 is switched to the low speed L and it is desired to return to the original H position, the second controller is operated when the shift button is switched to the H position while the vehicle is stopped. 80 energizes the electromagnetic switching valve 84, and this time, the hydraulic pressure from the hydraulic pump 72 is supplied to the port Q2 of the waiting mechanism 75 in the state of FIG. 5D, and the shift sleeve 98 is moved to the left to shift the shift rod 58. Will be switched to the H position.

  Here, in the friction clutch hydraulic control system 82 and the auxiliary transmission hydraulic control system 74A in the present embodiment of FIG. 2, the clutch control and shift switching control by the piston / cylinder mechanism constituting the hydraulic actuator are the same hydraulic pressure. Although the hydraulic pressure supplied from the pump 72 is used, the friction clutch 26 is basically controlled while the vehicle is running, and the sub-transmission switching control is performed when the vehicle is stopped. Even when the hydraulic pressure supplied from the hydraulic pump 72 is used, the motor 71 of the hydraulic pump 72 for the sub-transmission when the vehicle is stopped and the friction clutch by the hydraulic pump 72 driven by the motor 71 in the vehicle running state are used. There is no mutual interference.

  Further, the second controller 80 of the control unit 76 supplies the hydraulic pressure by the hydraulic pump 72 by rotating the motor 71 at a predetermined speed so as to generate the hydraulic pressure necessary for shift switching of the auxiliary transmission when the vehicle is stopped. The hydraulic pressure from the hydraulic pump 72 for controlling the auxiliary transmission is simultaneously supplied to the friction clutch control system 32 as it is. For this reason, the piston 36 is moved by the hydraulic pressure supply to the cylinder chamber 38 in the friction clutch control system 32, and the multi-valve clutch 48 is pressed through the pressing member 40.

  However, since the vehicle is stopped during the switching control of the sub-transmission, the multi-plate clutch 48 is in a stopped state, and even if the multi-plate clutch 48 of the pressing member 40 is pressed by the movement of the piston 38 in this state, the friction clutch 26 Torque transmission is not performed, and the operation is irrelevant. Therefore, even if the hydraulic pressure required for shift switching of the auxiliary transmission is generated on the hydraulic pump 72 side when the vehicle is stopped, there is no problem with the friction clutch control system 32.

  On the other hand, when the predetermined hydraulic pressure necessary for shift switching of the auxiliary transmission is supplied to the friction clutch control system 32 when the vehicle is stopped, the piston 36 moves and the pressing member 40 causes the initial state of the multi-plate clutch 48 to move. When the vehicle starts running in this state, the control response of the friction clutch 26 can be improved.

  In other words, the friction clutch control system is initially pressed in response to the hydraulic pressure generated in association with the sub-transmission switching control at the start of control, and is therefore accompanied by the rotation of the motor 71 from the first controller 78. The transmission torque control by the pressing force corresponding to the generated hydraulic pressure is quickly raised, and the control response of the friction clutch 26 can be improved.

  Further, in the embodiment of FIG. 2, the waiting mechanism 75 of the auxiliary transmission hydraulic control system 74A is integrally provided with a hydraulic drive mechanism by a piston cylinder mechanism, so that a shift actuator is provided separately. Thus, the transmission hydraulic control system can be reduced in size and weight.

  FIG. 6 is an explanatory view showing another embodiment in which the piston / cylinder mechanism in the sub-transmission control system is separated from the waiting mechanism.

  6, the friction clutch hydraulic control system 32 is the same as that of the embodiment of FIG. 2, but the auxiliary transmission hydraulic control system 74B is provided with a waiting mechanism 142 and a piston / cylinder mechanism separately. .

  That is, the shift fork 56 is fixed to the shift rod 58-2, and a waiting mechanism 142 is provided on the shift rod 58-2. In the waiting mechanism 142, a pair of slide rings 148 and 150 are slidably disposed on the shift rod 158-2 via a coil spring 146, and a shift sleeve 144 is slidably incorporated on the outside thereof.

  The pair of stopper rings provided on the right side of the shift rod 58-2 in the waiting mechanism 142 and the pair of stopper rings provided on the inner peripheral end of the shift sleeve 144 are the same as those of the waiting mechanism 75 in FIG.

  A shift rod 58-1 arranged in parallel to a shift rod 58-2 having a waiting mechanism 142 is connected to a piston 136 slidably housed in a cylinder 134, and hydraulic pressure is applied to one of the cylinder chambers 138, 140. The piston 136 is moved by the supply so that the shift rod 58-1 can be moved rightward or leftward.

  A connecting arm 152 is fixed to the shift rod 58-1, and the tip of the arm is connected to the shift sleeve 144 in the waiting mechanism 142. A switch cam 90 is provided on the shift fork 56, and position switches 86 and 88 that are turned on and off as the switch cam 90 moves in the axial direction are arranged. Check grooves 94 and 96 are provided on the left side of the shift rod 58-2, and a check ball 92 is fitted and positioned in the check groove 94 at the illustrated H position switching position.

  The cylinder chambers 138 and 140 partitioned by the piston 136 of the cylinder 134 can be controlled to switch the hydraulic pressure from the hydraulic pump 72 by the electromagnetic switching valves 82 and 84. The electromagnetic switching valves 82 and 84 are the same as in the embodiment of FIG. The branch pipe from the hydraulic pump 72 is connected to the ports Q1 and P3, the port P2 is connected to the port Q1 of the cylinder 134, and the port P4 is connected to the port Q2 of the cylinder 134. 82 and 84 are in a non-energized state so that the ports P2 and P4 are electrically connected to the tank port T, respectively, and the hydraulic pressures in the cylinder chambers 138 and 140 are set to zero.

  The hydraulic control in the auxiliary transmission hydraulic control system 74B is as follows. When the illustrated shift operation from the H position to the L position is performed by a button operation or the like while the vehicle is stopped, the second controller 80 of the control unit 76 rotates the motor 71 at a predetermined number of revolutions, and shift control is performed from the hydraulic pump 72. The electromagnetic switching valve 82 is energized while supplying the necessary hydraulic pressure.

  The electromagnetic switching valve 82 that has been energized switches from the switching position 82a so far to the switching position 82b, and the ports P1 and P2 communicate with each other to supply the hydraulic pressure from the hydraulic pump 72 to the cylinder chamber 138 from the port Q1. For this reason, when the piston 136 moves to the right side and reaches the position where the check ball 92 is fitted in the check groove 96, the switch cam 90 turns on the position switch 88 at this time and receives the position detection signal of the position switch 88 and receives the second detection signal. The controller 80 stops energization of the electromagnetic switching valve 82.

  If the phase of the shift gear shifted by the shift fork 56 does not match when the shift rod 58-1 is switched from the H position to the L position by this hydraulic control, the shift rod 58-2 cannot move and the shift rod 58-2 cannot move. In response to the movement of the connecting arm 158 accompanying the movement of 58-1 in the right direction, only the shift sleeve 144 in the waiting mechanism 142 moves to the right side with the coil spring 146 compressed, and enters a waiting state. In this case, since the position switch 88 does not output a position detection signal, energization of the electromagnetic switching valve 82 is continued.

  Thereafter, when the gear phases coincide with each other due to traveling of the vehicle, the shift rod 58-2 moves to the right by the force of the coil spring 146 in the compressed state of the waiting mechanism 142, and the shift fork 56 moves to the L position. Complete the switch. Here, the position switch 88 stops the energization of the electromagnetic switching valve 82 in order to output a position detection signal.

  In the auxiliary transmission hydraulic control system 74B of FIG. 6, the shift piston / cylinder mechanism is provided separately from the waiting mechanism 142, so that the arrangement space of the system increases correspondingly. Since the piston / cylinder mechanism is not integrated with each other, each structure becomes simple, and the cost can be reduced.

  FIG. 7 shows another embodiment in which the auxiliary transmission hydraulic system does not have a waiting mechanism. 7, the friction clutch hydraulic control system 32 is the same as that of the embodiment of FIG. The auxiliary transmission hydraulic control system 74C has a simple structure without a waiting mechanism.

  When this waiting mechanism is not provided, the waiting mechanism 142 on the shift rod 58-2 side in FIG. 6 is abolished, and the shift rod 58 is connected to a piston 136 slidably provided on the cylinder 134. A direct shift fork 56 may be provided.

  In the auxiliary transmission hydraulic control system 74C having no waiting mechanism, the shift fork 56 can be moved in the switching direction by the movement of the shift rod 58 by hydraulic drive if the shift gear is in phase, but the phase is not correct. If not, the shift rod 58 cannot move. In this case, the second controller 80 continues energization of the electromagnetic switching valve 82 until a position detection signal of the position switch is obtained.

  In this state, if there is a gear phase due to the start of running of the vehicle or the like, the shift rod 58 can be moved to the L position at that timing to switch to the L position, and a position detection signal is obtained, so the energization of the electromagnetic switching valve 82 is stopped.

The present invention includes appropriate modifications that do not impair the object and advantages thereof, and is not limited by the numerical values shown in the above embodiments.

Sectional drawing which showed embodiment of the driving force distribution apparatus for four-wheel drive vehicles by this invention Explanatory drawing which took out and showed the hydraulic control system for auxiliary transmissions with the hydraulic control system for friction clutches by this embodiment Sectional view of the waiting mechanism of this embodiment integrally provided with a piston / cylinder mechanism Explanatory drawing which showed operation | movement of the waiting mechanism of this embodiment integrally provided with the piston and cylinder mechanism. Explanatory drawing showing the operation of the waiting mechanism following FIG. Explanatory drawing of other embodiment which separated piston / cylinder mechanism and waiting mechanism Explanatory drawing of other embodiment which does not have a waiting mechanism

Explanation of symbols

10: Case (front)
11: Case (rear)
12: input shaft 14: auxiliary transmission mechanism 16: sun gear 18: planetary gear 20: carrier case 22: ring gear 24: rear wheel output shaft 25, 31: sprocket gear 26: friction clutch 28: chain belt 30: front wheel output shaft 32 : Friction clutch hydraulic control system 34, 134: Cylinder 36, 136: Piston 38, 138, 140: Cylinder chamber 40: Pushing member 44: Clutch hub 46: Clutch drum 48: Multi-plate clutch 49: Return spring 52: Shift gear 53 : Clutch gear (H position)
54: Clutch gear (L position)
56: Shift fork (for HL switching)
58: Shift rod 60: Waiting mechanism 62: Spring 64: Stopper ring 70: Actuator unit 71: Motor 72: Hydraulic pumps 74A, 74B, 74C: Sub-transmission hydraulic control system 75, 142: Waiting mechanism 76: Control unit 78 : First controller 80: Second controller 81: Vehicle state detection unit 82 and 84: Electromagnetic switching valve 85: Pressure sensor 86 and 88: Position switch 90: Switch cam 92: Check ball 94 and 96: Check groove 98 and 144: Shift sleeve 100, 102, 148, 150: Slide ring 104, 146 Coil spring 106, 108, 110, 112: Stopper ring 114: Piston portion 116: Cylinder 118, 120: Cylinder chamber 122, 124: Lock pin 126, 128: Plate Spring 130 132: lock groove

Claims (5)

A friction clutch that selectively transmits torque from the main output shaft to the sub output shaft;
A sub-transmission that switches the power from the input shaft to at least two stages of high speed and low speed and transmits it to the main output shaft;
In the driving force distribution device for a four-wheel drive vehicle equipped with
A friction clutch hydraulic control system for controlling a transmission torque by changing a pressing force of the friction clutch according to a supply hydraulic pressure of a hydraulic source including a motor and a hydraulic pump;
A sub-transmission hydraulic control system that switches and controls the sub-transmission by the supply hydraulic pressure of the hydraulic source;
A driving force distribution device for a four-wheel drive vehicle.
In the driving force distribution device for a four-wheel drive vehicle according to claim 1,
The friction clutch hydraulic control system includes:
A first piston for pressing the friction clutch;
A first cylinder that slidably houses the first piston;
A hydraulic pump that supplies oil to the first cylinder during forward rotation and discharges oil from the first cylinder during reverse rotation;
A pressure sensor for detecting the hydraulic pressure generated by the hydraulic pump;
A motor for driving the hydraulic pump forward and backward, and
A first controller for controlling forward / reverse drive of the motor to control a pressing force of the friction clutch to a predetermined value so that a detected hydraulic pressure of the pressure sensor becomes a predetermined set hydraulic pressure;
With
The auxiliary transmission hydraulic control system includes:
A second piston for moving a shift fork attached to the shift rod to a switching position;
A second cylinder that slidably houses the second piston;
A pair of electromagnetic switching valves provided corresponding to each of the cylinder chambers formed on both sides of the second piston, supplying oil to the cylinder chamber when energized and discharging oil from the cylinder chamber when de-energized;
A position sensor for detecting the shift fork reaching the switching position;
When the shift fork is moved to one of the switching positions, one of the pair of electromagnetic switching valves is controlled in a state where oil of a predetermined hydraulic pressure is supplied from the hydraulic pump by controlling forward / reverse rotation of the motor. A second controller that energizes and supplies oil to the corresponding cylinder chamber of the second piston and stops energization of the electromagnetic switching valve when the position sensor detects that the shift fork has reached the switching position; ,
A driving force distribution device for a four-wheel drive vehicle.
The drive force distribution device for a four-wheel drive vehicle according to claim 2, wherein the auxiliary transmission hydraulic control system includes:
A four-wheel drive vehicle comprising a waiting mechanism between the shift rod and the shift fork for compressing a spring against the movement of the shift rod to the switching position and urging the shift fork in the switching direction. Drive power distribution device.
4. The driving force distribution device for a four-wheel drive vehicle according to claim 3, wherein the second piston, the second cylinder, and the waiting mechanism are integrated.
The drive force distribution device for a four-wheel drive vehicle according to claim 4,
The waiting mechanism is
A pair of slide rings slidably inserted into the shift rod;
A spring disposed between the pair of slide rings;
A shift sleeve slidably disposed outside the pair of slide rings;
A pair of first stopper rings that are fitted to the shift rod and engage the inner peripheral end surfaces of the pair of slide rings;
A pair of second stopper rings that are fitted to the inner peripheral surface of the shaft hole of the shift sleeve and lock the end surface portions on the outer peripheral side of the pair of slide rings;
A piston portion constituting the second piston integrally formed by projecting annularly on the outer periphery of the shift sleeve;
A cylinder constituting the second cylinder that slidably houses a shift sleeve having the piston portion;
It is located in each of the cylinder chambers on both sides partitioned by the piston portion, and is fitted and locked to the shift sleeve by urging by a spring member, and moves as a piston when hydraulic pressure is supplied to unlock the shift sleeve. A pair of lock pins;
A driving force distribution device for a four-wheel drive vehicle.

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