JPH0495552A - Hydraulic controller for controlling auxiliary wheel of vehicle - Google Patents

Abstract

PURPOSE:To height reliability and smoothability on operation by installing a relief valve, and making a hydraulic fluid feedable to a hydraulic rotating actuator only in the state that the uplift of a car body is maintained, in a hydraulic controller which controls an auxiliary wheel for shifting a part of the car body in the body cross direction. CONSTITUTION:In a hydraulic controller for a vehicle, which assembles an auxiliary wheel ratable around an axis in the longitudinal direction of a car body movably up and down to the car body by means of a hydraulic cylinder 13 in a front part or rear part of the car body and thereby facilitates a file of parking at a narrow place, it is provided with a solenoid selector valve 25 being installed in a power steering system, and when this valve 25 is energized with current, a hydraulic fluid is fed to an upper oil chamber of the hydraulic cylinder 13. In addition, an oil passage P is branched off from an oil passage P1 lying between a check valve 26 and the hydraulic cylinder, and this oil passage P2 is connected to an auxiliary wheel hydraulic motor 15 via a relief valve 27 and a solenoid selector valve 28. This relief valve 27 is constituted so as to allow the interconnection of the oil passage P2 in the state that each of the hydraulic fluid in the hydraulic cylinder 13 and these oil passages P1, P2 becomes enhanced to the full.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention provides a method for moving a part of the vehicle body in the lateral direction of the vehicle body to enable parallel parking in narrow spaces. The present invention relates to a hydraulic control device for controlling the auxiliary wheels of a vehicle, which lowers the auxiliary wheels to lift the vehicle body and rotationally drives the auxiliary wheels.

[Prior art] Conventionally, this type of device has been disclosed in, for example, Utility Model Application Publication No.
As shown in the publication, the auxiliary wheels are lowered toward the road surface by a hydraulic jack attached to the rear part of the vehicle body at the upper end, and the rear part of the vehicle body is lifted up, and in this lifted state, hydraulic oil is supplied to the hydraulic jack. A hydraulic rotary actuator connected to an oil passage branched from the oil passage is instructed to rotate, and the actuator drives the auxiliary wheels to rotate, rotating the rear part of the vehicle body around the front part of the vehicle body, and rotating the rear part in the lateral direction of the vehicle body. I was trying to move it to .

However, in the conventional device described above, the hydraulic rotary actuator may accidentally rotate the auxiliary wheels before the hydraulic jack completes lifting the rear part of the vehicle body, or the vehicle body may be damaged by the hydraulic jack. After the rear part has been lifted, if the hydraulic rotary actuator continues to rotate the auxiliary wheels while the lift is no longer maintained and the vehicle body is lowered, all four wheels (left and right front wheels and right and left rear wheels) may contact the road surface. The auxiliary wheels will rotate on the road surface in this state, which may cause excessive load to be applied to the hydraulic rotary actuator, wear of the auxiliary wheels due to friction with the road surface, and cause hydraulic jacking and excessive lateral damage to the rear of the vehicle. This may cause the vehicle to move in a direction not intended by the driver.

The present invention was made in order to deal with the above problem, and its purpose is to supply hydraulic oil to the hydraulic rotary actuator on the condition that the hydraulic oil is supplied to the hydraulic jack at a value higher than the hydraulic pressure required to lift and maintain the vehicle body. To provide a auxiliary wheel device for a vehicle, in which the auxiliary wheels are rotated by a hydraulic rotary actuator only when lifting of the rear part of the vehicle body by a hydraulic jack is completed and maintained. It is.

[Means for Solving the Problems 1] In order to achieve the above object, the structural features of the present invention are as follows:
The upper end part is attached to the front or rear part of the vehicle body, and the lower part supports the auxiliary wheel rotatably around the longitudinal axis of the vehicle body, and the auxiliary wheel is supported by supplying hydraulic oil through the first oil path. a hydraulic jack that lifts the front or rear part of the vehicle body by lowering it toward the road surface; A hydraulic control device for controlling a auxiliary wheel of a vehicle, comprising a hydraulic rotary actuator that rotationally drives the auxiliary wheel by hydraulic oil supplied through a second oil passage, wherein the hydraulic rotary actuator is interposed in the second oil passage and the When the working oil pressure on the first oil path side is equal to or higher than the oil pressure value for lifting and maintaining the vehicle body by the hydraulic jack, the supply of hydraulic oil to the hydraulic rotary actuator is permitted, and when the working oil pressure is less than the same oil pressure value, This is due to the provision of a relief valve that prohibits the supply of hydraulic oil.

[Function] In the present invention configured as described above, when the working oil pressure on the first oil path side of the relief valve is equal to or higher than the oil pressure value at which the vehicle body is lifted and maintained by the hydraulic jack, the valve is opened via the second oil path. Since hydraulic fluid is supplied to the hydraulic rotary actuator, the actuator can rotate the auxiliary wheels in response to instructions from the outside. Therefore, in this case, with the vehicle body lifted up, the auxiliary wheels rotate around the axis in the longitudinal direction of the vehicle body, causing the front or rear portion of the vehicle body to move laterally. Furthermore, when the hydraulic pressure on the first oil path side of the relief valve is less than the oil pressure value required to lift and maintain the vehicle body using a hydraulic jack, opening the valve prohibits the supply of hydraulic oil to the hydraulic rotary actuator via the second oil path. Therefore, even if a rotation instruction is given from the outside, the hydraulic rotary actuator will not rotate.

Effect of the Invention 1 As can be understood from the above description of the operation, according to the present invention, by providing the relief valve, hydraulic oil is supplied to the hydraulic rotary actuator for the first time only when the vehicle body is maintained lifted. This makes it possible to rotate the auxiliary wheels using the same actuator, so the auxiliary wheels do not rotate on the road surface with all four wheels (left and right front wheels and left and right rear wheels) in contact with the road surface. excessive load may be applied, the auxiliary wheels may wear out due to friction with the road surface, excessive lateral force may be applied to the hydraulic jacks or the rear of the vehicle, or the vehicle may move in a direction unintended by the driver. disappears.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. Figs. 2 and 3 are schematic views of a vehicle according to the embodiment as seen from the side and rear.

This vehicle has left and right front wheels FWI, FW2 and left and right rear wheels RW.
In addition to I, RW2, auxiliary w111 as the fifth wheel
The auxiliary 1111 is assembled to be movable up and down relative to the vehicle body BD by a hydraulic jack mechanism 10. The hydraulic jack mechanism 10 is made up of a support 1i12 and a hydraulic cylinder 13, and the support arm 12 is mounted on the rear lower surface of the vehicle body BD at the upper part thereof, at approximately the center position in the lateral direction of the vehicle, and around the axis in the longitudinal direction of the vehicle. It is swingably supported, and the auxiliary wheel 11 is supported rotatably around an axis in the longitudinal direction of the vehicle at its lower end and on the side surface. The hydraulic cylinder 13 has a cylinder tube 13a inclined in the lateral direction of the vehicle, and one end of the cylinder tube 13a is on the side of the support arm 12 and can swing around the axis in the longitudinal direction of the vehicle on the lower surface of the vehicle body BD. The piston rod 13b protrudes from the other end. One end of this piston rod 13b is attached to the support arm 12 at an intermediate position so as to be rotatable around an axis in the longitudinal direction of the vehicle, and the other end has a cylinder tube 13a attached to the upper and lower chambers, as shown in FIG. A piston 13c is fixed.

A spring 14 is housed in the lower chamber of the cylinder tube 13a, and the spring 14 always urges the piston 13c and the piston rod 13b upward.

The support arm 12 has a hydraulic motor 15 as a rotary actuator fixed on the side opposite to the auxiliary wheel 11, and the motor 15 has its rotating shaft connected to the center axis of the auxiliary wheel 11, as shown in FIG. As shown, the auxiliary wheels 11 are driven in forward rotation and reverse rotation depending on the direction in which hydraulic oil is supplied and discharged.

Next, a hydraulic control device A and an electric control device B that drive and control the hydraulic cylinder 13 and the hydraulic motor 15 using FIG.
I will explain about it.

The hydraulic control device A includes a hydraulic pump 21, a control valve 22, and a power cylinder 2 driven by an engine (not shown).
The power steering device includes an electromagnetic switching valve 25 interposed in a power steering device consisting of a power steering device 3 and a reservoir 24. The electromagnetic switching valve 25 is set to the first state (the state shown in the figure) when not energized to supply oil discharged from the hydraulic pump 21 to the control valve 22, and is switched to the second state when energized to direct the hydraulic oil to the oil path. It is supplied to the upper oil chamber of the cylinder tube 13a via P1. A check valve 26 is interposed in the oil passage P1, and the check valve 26 prevents the hydraulic oil from flowing back to the electromagnetic switching valve 25 in the oil passage P1. Note that the lower oil chamber of the cylinder tube 13a communicates with the reservoir 24.

An oil passage P2 branches from the oil passage P1 between the check valve 26 and the cylinder tube 13a, and the oil passage P2 guides hydraulic oil to the hydraulic motor 15 via a relief valve 27 and an electromagnetic switching valve 28. The relief valve 27 is normally in the illustrated state and prohibits communication of the oil passage P2, and when the supply of hydraulic oil into the upper reservoir chamber of the cylinder tube 13a via the oil passage P1 is completed, the hydraulic pressure of the oil passages Pi and P2 is When the piston 13c is sufficiently high (the piston 13c is sufficiently lowered and the vehicle body BD is sufficiently lifted), the oil passage P2 is allowed to communicate, and the hydraulic oil is transferred through the oil passages Pi and P2 to the electromagnetic switching valve. 28. When the electromagnetic switching valve 28 is de-energized, the first
state (the state shown), the supply port communicating with the relief valve 27 is closed, and the input/output ports 15a, 15b of the hydraulic motor 15 are communicated with the discharge port communicating with the reservoir 24. Further, the electromagnetic switching valve 28 is set to the second state (lower display position) in the first energized state, and supplies the hydraulic oil from the relief valve 27 to the input/output boat 15a of the hydraulic motor 15. The hydraulic oil from the output boat 15b is discharged into the reservoir 24, and the motor 15 is rotated in the normal direction. Further, the electromagnetic switching valve 28 is set to the third state (upper display position) when the 12 is energized, and supplies the hydraulic oil from the relief valve 27 to the input/output boat 15b of the hydraulic motor 15. The hydraulic oil from 15a is discharged into the reservoir 24, and the motor 15 is reversed.

Also, from the branch point of the oil passage P2 to the oil passage P1, the oil passage P3
The oil passage P3 further branches into the oil passage P4.
The oil passages P4 and P5 are respectively provided with an electromagnetic switching valve 31 and a relief valve 32. When the electromagnetic switching valve 31 is de-energized, it is set to the first state (the state shown in the figure) to prohibit communication of the oil passage P4, and when it is energized, it is set to the second state to direct the oil passage P4 to the reservoir 24 via the throttle 31a. communicate. The relief valve 32 is normally in the state shown and prohibits communication of the oil passage P5, and the oil passages P1 to
When the oil pressure of P5 becomes higher than the oil pressure value required for maintaining the downward movement of the piston 13c and controlling the rotation of the hydraulic motor 15, the oil passage P5 is allowed to communicate with the reservoir 24.

The electric control device B includes a microcomputer 41 consisting of a ROM, a CPU, a RAM, an input/output interface, etc., and the computer 41 controls the auxiliary wheel operation switch 42 by executing a program corresponding to the flowchart in FIG. Rotation instruction switch 43, vehicle speed sensor 4
4. Controls energization and de-energization of the electromagnetic switching valves 25, 28, and 31 according to signals from the shift position detection switch 45, the ascent completion detection switch 46, and the descent completion detection switch 47.

The auxiliary wheel actuation switch 42 is provided near the driver's seat and instructs the auxiliary wheel 11 to rise and fall, and when in an on state, it instructs to raise the auxiliary wheel 11, and when in an off state, it instructs to lower it. A return actuator 48 is attached to the auxiliary wheel operating switch 42, and the actuator 48 is controlled by the microcomputer 41 to return the auxiliary wheel operating switch 42 from the on state to the off state. The rotation instruction switch 43 is provided near the driver's seat and instructs the rotation of the hydraulic motor 15 (auxiliary wheels 11).It instructs the stopped state of the motor 15 in the neutral state, and also instructs the stopped state of the motor 15 in the upper and lower switching positions. Directs forward and reverse rotation of the motor 15, respectively.

Vehicle speed sensor 44 detects the rotational speed of an output shaft of a transmission (not shown) and outputs a detection signal representing vehicle speed. The shift position detection switch 45 detects the operating position of the shift lever of the transmission and outputs a detection signal representing the operating position.

Ascent completion detection switch 46 and descent completion detection switch 4
7 are both provided in the vicinity of the hydraulic cylinder 13, and the lift completion detection switch 46 is normally in an OFF state, but turns on when the auxiliary wheel 11 is raised and retracted to the lower surface of the vehicle body. Further, the lowering completion detection switch 47 is normally in an OFF state, and is turned ON when the auxiliary wheels 11 have lowered and the vehicle body BD has completed rising.

Next, the operation of the embodiment configured as described above will be explained in detail with reference to the flowchart shown in FIG.

When the ignition switch (not shown) is closed, the microcomputer 41 starts executing the program at step 5o in FIG. ! 11! F device B
Execute the first wI determination. In this initial setting, the electromagnetic switching valves 25, 28.degree. 31 are each set to the state shown in FIG. In this state, the hydraulic oil from the hydraulic pump 21 is being supplied to the control valve 22 via the electromagnetic switching valve 25, and the hydraulic oil is being supplied to the control valve 22 through the electromagnetic switching valve 25 to the left and right front wheels FW1. Steering of the FW2 is assisted by a power cylinder 23.

After this initial setting, each detection signal from the vehicle speed sensor 44 and shift position detection switch 45 is read in step 52.
condition that the vehicle speed is "0" and the shift lever is in the neutral (or parking) state.
It is detected that the vehicle is completely stopped.

If the vehicle is not stopped now, based on the determination of rNOJ in step 52, it is determined in step 53 whether or not the auxiliary wheel operation switch 42 is turned on. In this case, if the auxiliary wheel operation switch 42 is not turned on, it is determined that rNOJ is in step 53, and the program proceeds to step 55. However, if the switch 42 is turned on, step 53 is determined to be rNOJ, and the program proceeds to step 55. Based on the determination that rYEsJ, a drive signal is output to the return actuator 48 in step 54, and the program proceeds to step 55. Through the process of step 54, the return actuator 48 returns the auxiliary wheel activation switch 42 to the OFF state, so even if the auxiliary wheel activation switch 42 is operated while the vehicle is running, the operation is canceled.

In step 55, the electromagnetic switching valve 25 is controlled to be de-energized, and the switching valve 25 is maintained in the first state.

As a result, as in the initial case, the oil discharged from the hydraulic pump 21 is supplied to the i'II# valve 22, so that the left and right front wheels FWI and FW2 can be steered when the steering wheel 52 is rotated while the vehicle is running. is assisted by the power cylinder 23.

After the processing in step 55, the detection signal from the ascent completion detection switch 46 is read in step 56, and it is determined whether or not the switch 46 is in the on state. In this case, if the auxiliary wheel 11 has risen and is not completely retracted to the lower surface of the vehicle body BD, the electromagnetic switching valve 31 is energized in step 57 based on the determination of "N○" in step 56. Switched to the second state. On the other hand, since the piston 13c is urged upward by the spring 14, the hydraulic oil in the upper reservoir chamber of the cylinder tube 13a flows through the oil passages PI, P3. P4 and the throttle 3 of the electromagnetic switching valve 31
1a to the reservoir 24 and the piston rod 1
3b is displaced upward, that is, the amount of protrusion relative to the cylinder tube 13a is reduced. As a result, the support arm 12 is attached to the vehicle body B.
The auxiliary wheel 11 is controlled to rise by swinging counterclockwise in FIG. 3 using the upper end supported by D as a fulcrum. and.

r in step 56 until the raising of the auxiliary wheel 11 is completed.
NOJ, that is, it is determined that the ascent completion detection switch 46 is not in the on state, and the circulation process consisting of steps 56 and 57 is repeatedly executed, and the ascent control of the auxiliary wheels 11 is continued. In addition, in this increase control, the aperture 3
1a, the hydraulic oil slowly flows out into the reservoir 24, so the auxiliary wheel 11 also gradually rises.

When the raising of the auxiliary wheel 11 is completed by this raising control and the auxiliary wheel 11 is retracted to the lower surface of the vehicle body BD, the raising completion detection switch 46 is turned on, so in step 56 it is determined as rYESJ. In step 58, the electromagnetic switching valve 31 is de-energized and the facing valve 31 is returned to the first state (initial state).

After the processing in step 58, in step 59, the auxiliary wheel operation switch 42, rotation instruction switch 43, vehicle speed sensor 44, various detection switches 45 to 47, electromagnetic switching valve 2
5.28.31 is checked and if an abnormality is detected in the various parts, it is determined in step 59 that rYEsJ, that is, the turning control of the auxiliary wheels 11 is canceled, and the program execution is terminated in step 60. Ru.

On the other hand, if no abnormality is detected in any of the various parts, the program returns to step 52 based on the determination of NOJ in step 59. If the vehicle is not stopped, the process consisting of steps 53 to 59 described above is performed based on the determination of "No" in step 52.

The vehicle is currently stopped and rYES is selected in step 52.
If it is determined as J, in step 61, the step 53
In the same manner as above, it is determined whether the auxiliary wheel operation switch 42 is in the on state. In this case, the auxiliary wheel activation switch 4
2 is not turned on and the switch 42 is in the off state, rNOJ is determined in step 61, the processes in steps 55 to 59 described above are executed, and the auxiliary wheel 11 is moved to the lower surface of the vehicle body BD. Remains stored.

Further, when the auxiliary wheel operation switch 42 is turned on and it is determined in step 61 that rYESJ, that is, the switch 42 is in the on state, the detection signal from the lowering completion detection switch 47 is read in step 62. It is determined whether the switch 47 is in the on state. In this case, if the descent completion detection switch 47 is not in the on state,
In other words, if the lowering of the auxiliary wheels 11 is completed and the vehicle body BD is not lifted up, in step 62 r N C) J
It is determined that the electromagnetic switching valve 25 is energized in step 63, and the opposite valve 25 is set to the second state. After the process of step 63, the program returns to step 62, and the cyclic process consisting of steps 62 and 63 continues to be executed until the ON state of the lowering completion detection switch 47 is detected.

During the circulation process, the electromagnetic switching valve 25 is set to the second state, so that the oil discharged from the hydraulic pump 21 is transferred to the electromagnetic switching valve 25. The oil is supplied to the upper oil chamber of the cylinder tube 13a via the check valve 26 and the oil passage P1. With this supply of hydraulic oil, the piston 13c and the piston rod 13b are displaced downward against the urging force of the spring 14, and the rod 13b presses the intermediate position of the support arm 15 toward the lower left in FIG. 3. As a result, the support arm 15 swings clockwise in FIG. 3 using the upper end supported by the vehicle body BD as a fulcrum, and the auxiliary wheel 11 descends to come into contact with the road surface GR. In this case, the electromagnetic switching valve 28 remains initially set to state 11 (the state shown in FIG. Since the motor 15 is in a rotatable state, this auxiliary wheel 11
After contacting the auxiliary wheel 11, the external force from the road surface OR
While rotating, the swinging of the support arm 15 continues. As a result, the support arm 15 pushes up the lower surface of the vehicle body BD, so that the vehicle body BD gradually rises. And left and right rear wheels RWI
, when RW2 leaves the road surface GR and the support arm 15 becomes substantially upright, the piston 13c and piston rod 13b, which have been displaced downward by the supply of hydraulic oil to the cylinder tube 13a, reach the lowest point, and the completion of the descent is detected. The switch 47 is turned on.

When the lowering completion detection switch 47 is turned on in this way, during the circulation process consisting of steps 62 and 63,
At step 62, rYESJ is determined, and the program proceeds to step 64 and subsequent steps.

On the other hand, in this state, the oil discharged from the hydraulic pump 21 does not further flow into the upper oil chamber of the cylinder tube 13a, so the working oil pressure in the oil passage Pi-P5 increases. As a result of this rise, the relief valve 27 opens the oil passage P2 and starts supplying oil discharged from the hydraulic pump 21 to the electromagnetic switching valve 28.

Therefore, no matter what state the electromagnetic switching valve 28 is in, high-pressure hydraulic oil will not be supplied to the hydraulic motor 15 until the left and right rear wheels RWI, RW2 are separated from the road surface GR and the vehicle body BD is completely lifted. , the motor 15 does not rotate the auxiliary wheels.

Further, at this time, if the electromagnetic switching valve 28 is in the first state, the oil discharged from the hydraulic pump 21 does not pass through the open valve 28, so that the working oil pressure in the oil passages P1 to P5 further increases. Then, when this working oil pressure becomes higher than the oil pressure value required for the downward maintenance control of the piston 13c and the rotation control of the hydraulic motor 15, the relief valve 32 allows communication of the oil passage P5, and the discharge oil from the hydraulic pump 21 is released. are oil passages Pi, P
3, is discharged to the reservoir 24 via P5. As a result, the working oil pressure in the oil passage Pi-P5 does not become higher than necessary, and the oil pressure! 11 Oil will not leak from any part of the control device A.

On the other hand, in step 64, the rotation instruction switch 43
The state of the switch 43 is determined by reading the signal from the switch 43. If the rotation instruction switch 43 is currently maintained in a state instructing the hydraulic motor 15 to stop (neutral state), it is determined in step 64 that a "stop instruction" is issued, and in step 65 the electromagnetic switching valve 28 is set to the first state. (the state shown in FIG. 1) is maintained, and the program returns to step 52. As a result, in this case, the vehicle body BD remains lifted,
The circulation process consisting of steps 52, 61 to 65 continues to be repeatedly executed, and as described above, the oil discharged from the hydraulic pump 21 flows through the oil paths P1, P3, . It continues to be discharged to the reservoir 24 via P5 and the relief valve 32.

On the other hand, if the rotation instruction switch 43 is operated to instruct the hydraulic motor 15 to rotate in the normal direction, the "forward rotation instruction" is executed in step 64.
In step 66, the electromagnetic switching valve 28 is set to the second state (lower display position in FIG. 1) by energization control. As a result, the discharge oil from the hydraulic pump 21 via the oil passage P2 and the relief valve 27 is supplied to the inflow/output port 15a of the hydraulic motor 15, and the hydraulic oil from the inflow/output port 15b of the motor 15 is supplied to the reservoir 24. Therefore, the hydraulic motor 15 rotates normally and starts rotating the auxiliary wheel 11 clockwise in FIG. 3. As a result, as shown in Figure 5, the parallel parked vehicle rotates counterclockwise around the front of the vehicle, as shown by the solid line in the figure, and the space in front and behind the vehicle becomes narrower. Even if the vehicle is parked, the vehicle can be pulled out of the parked state.

Further, if the rotation instruction switch 43 is operated to instruct the hydraulic motor 15 to reverse rotation, the "reverse rotation instruction" is issued in step 64.
In step 67, the electromagnetic switching valve 28 is set to the third state (upper display position in FIG. 1) by energization control. As a result, the oil discharged from the hydraulic pump 21 via the oil passage P2 and the relief valve 27 is supplied to the inflow/outflow port 15b of the hydraulic motor 15, and the hydraulic oil from the inflow/output port 15a of the motor 15 is supplied to the reservoir 24. As the oil is being discharged, the hydraulic motor 15 reverses and starts rotating the auxiliary wheel 11 counterclockwise in FIG. 3. As a result, when the vehicle is stopped as shown in Figure 5, it rotates counterclockwise around the front of the vehicle body, as shown by the broken line in the figure, so it can be used even in places where the space in front and behind the vehicle is narrow. The vehicle can be parallel parked.

After the processing of steps 65 to 67, the program returns to step 52, and the microcomputer 41 executes a circulation process consisting of steps 52, 61 to 67, and continues to control the rotation of the auxiliary wheel 11 described above. During this rotation control, when the hydraulic pressure of the oil passage P1 decreases and the vehicle body BD begins to descend, the relief valve 27 is switched to the first state and prohibits communication of the oil passage P2. As a result, in this case, no matter what state the electromagnetic switching valve 28 is in, high-pressure hydraulic oil is not supplied to the hydraulic motor 15, so the auxiliary wheel 11 is not rotationally driven by the motor 15.

As described above, according to the embodiment, sufficiently high-pressure hydraulic oil is supplied from the hydraulic pump 21 to the upper reservoir chamber of the cylinder tube 13a through the oil path P1, and the vehicle body BD is completely lifted. Only when the left and right rear wheels RWI, RW2 are away from the road surface GR, the relief valve 27 communicates the oil passage P2 and transfers the hydraulic oil in the oil passage P1 to the oil pressure via the oil passage P2 and the electromagnetic switching valve 28. Supplied to the motor 15.

Therefore, the auxiliary wheels 11 are no longer rotationally driven on the road surface GR by the hydraulic motor 15 while the left and right rear wheels RWI, RW2 are in contact with the road surface GR.

Excessive load may be applied to the hydraulic motor 15 to move the rear part of the vehicle body BD laterally, the auxiliary wheels 11 may wear out due to friction with the road surface, or excessive lateral force may be applied to the support arm 12 and the rear part of the vehicle body BD. This prevents the vehicle from moving in a direction not intended by the driver.

Further, in the above embodiment, the cylinder tube 13a
A spring 14 is provided in the lower basin chamber to constantly bias the piston 13c and piston rod 13b upward, and the biasing force of the spring 14 is used when controlling the raising of the auxiliary wheel 11, thereby eliminating unnecessary energy loss. be able to. Further, even if there is an oil leak in the hydraulic control device A, the auxiliary wheels 11 are controlled to rise by the spring 14, so it is possible to prevent the auxiliary wheels 11 from descending while the vehicle is running.

Furthermore, in the embodiment described above, the check valve 26 is interposed in the oil passage P1, so that the hydraulic oil in the oil passage P1 is supplied to the hydraulic pump 21.
Since backflow to the side is prevented, even when the hydraulic pump 21 stops ejecting high-pressure hydraulic oil due to engine stoppage, the hydraulic pressure in the oil passages P1 to P5 is maintained at high pressure, and the lifted vehicle body is maintained at a high pressure. The BD does not descend due to the engine stopping. Thereby, it is safe even when the hydraulic jack 10 according to the above embodiment is used to lift the vehicle body BD to change tires, attach chains, etc.

In the above embodiment, the auxiliary wheel 11 is provided near the center of the rear part of the vehicle body BD, but it may be provided near the center of the front part of the vehicle body, that is, the left and right front wheels FWI, FW2. In this case, the front part of the vehicle body BD rotates left and right around the rear part.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a hydraulic and electrical control device according to an embodiment of the present invention, FIG. 2 is a schematic side view of a vehicle according to the embodiment, and FIG. 3 is a rear view of a vehicle according to the embodiment. FIG. 4 is a flowchart of a program executed by the microcomputer shown in FIG. 1, and FIG. 5 is a plan view of a vehicle showing one mode of using the auxiliary wheels in the same embodiment. Explanation of symbols A: Hydraulic control device, B: Electrical control device, P1~
P5 ・ ・ Oil path, BD ・ ・ Vehicle body, O
R...Road surface, 10...Hydraulic jack mechanism, 11
... Auxiliary wheel, 12... Support arm, 13... Hydraulic cylinder, 15... Hydraulic motor, 21... Hydraulic pump, 2
5, 28.31...Solenoid switching valve, 27.32.
...Relief valve, 26...Check valve, 41...
Microcomputer, 42... Auxiliary wheel operation switch, 43... Rotation instruction switch. Applicant Toyota Motor Corporation Representative Patent Attorney Teru Hase (1 other person) Figure 2 Figure 3 Figure

Claims (1)

[Claims] The upper end part is attached to the front or rear part of the vehicle body, and the lower end part supports the auxiliary wheel rotatably around the longitudinal axis of the vehicle body, and the auxiliary wheel is attached to the road surface by supplying hydraulic oil through the first oil path a hydraulic jack that lifts the front or rear part of the vehicle body by lowering it toward In a hydraulic control device for controlling an auxiliary wheel of a vehicle, comprising a hydraulic rotary actuator that rotationally drives an auxiliary wheel by hydraulic oil supplied through an oil passage, the hydraulic rotary actuator is provided with the second oil passage and the second oil passage is interposed in the second oil passage. 1. Allowing the supply of hydraulic oil to the hydraulic rotary actuator when the working oil pressure on the oil road side is equal to or higher than the oil pressure value at which the vehicle body is lifted and maintained by the hydraulic jack, and operating the same when the working oil pressure is less than the same oil pressure value. A hydraulic control device for controlling a auxiliary wheel of a vehicle, characterized by being provided with a relief valve that prohibits oil supply.