JPH0468162B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a vehicle height adjustment device for adjusting the vehicle height of an automobile.

(Prior Art) The vehicle height adjustment device described above supplies and discharges pressurized fluid from a pump and normal pressure oil to and from a fluid actuator that is generally located between the vehicle body and the wheels and supports the vehicle body by switching a vehicle height adjustment valve. to adjust the vehicle height. In addition to actually adjusting the vehicle height, the fluid actuator also functions to maintain the vehicle height at a predetermined height, but from the viewpoint of riding comfort, it is necessary to improve the sealing performance of the sliding part. Therefore, the vehicle height could not be maintained at a predetermined height due to pressure oil leakage during long-term use.

Therefore, in the vehicle height selection device of Japanese Patent Publication No. 51-21852, the manual lever that sucks and discharges hydraulic oil into the fluid actuator is set at a hydraulic oil replenishment position where hydraulic oil is constantly supplied into the fluid actuator.
When the manual lever is in this hydraulic oil replenishment position, the fluid actuator is supplied with hydraulic oil corresponding to the amount of leakage.

(Problem to be Solved by the Invention) The vehicle height selection device disclosed in Japanese Patent Publication No. 51-21852 is designed to accurately control the amount of hydraulic fluid leaked from the fluid actuator without creating an unbalance in vehicle height between each wheel. However, since replenishment requires operating a lever, there is a risk of forgetting to replenish.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a vehicle height adjustment device for an automobile that can automatically replenish the amount of pressure oil leaked from the fluid actuator.

(Means for Solving the Problems) The present invention provides that the amount of pressure oil leaking from the fluid actuator is mainly caused by the up and down movement of the wheels relative to the vehicle body during vehicle rolls, dives, scoots, etc. Considering that the number of operations depends on the number of operations, pressurized fluid from the pump is supplied and discharged by switching the vehicle height adjustment valve to the fluid actuator that is located between the vehicle body and the wheels and supports the vehicle body, thereby preventing leakage of the pressure fluid. a vehicle height adjustment device that adjusts the vehicle height only when the vehicle is abnormal, and a driving state detection means that detects the number of expansion and contraction operations of a fluid actuator as each wheel moves up and down with respect to the vehicle body;
In accordance with the output signal from the running state detection means, the vehicle height adjustment valve is controlled to supply pressure fluid to the fluid actuator, and the amount of pressure fluid leaked from the fluid actuator due to the operation of the fluid actuator is reduced. It is characterized by being equipped with supplementary pressure fluid supply means.

(Function/Effect) The vehicle height adjustment device of the present invention configured as described above detects the operation of the fluid actuator and automatically compensates for the leakage of pressure fluid based on this. can always be maintained at the target value, improving driving stability.

(Embodiments) Hereinafter, a vehicle height adjustment device for an automobile according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

In FIG. 1, reference numeral 1 indicates a vehicle body, and reference numeral 2 indicates a wheel, and this wheel 2 is rotatably supported by a wheel support member 3. This wheel support member 3 has a lower end 3a connected to the frame 1a of the vehicle body 1 via a lower arm 4, and
Its upper end 3b is connected to the vehicle body 1 via a strut 5 as a fluid actuator for adjusting vehicle height, and the lower arm 4 regulates the movement of the wheel 2 in the vehicle width direction, and also dampens the vertical vibration of the wheel 2. It is designed to be absorbed by strut 5.

As shown in FIG. 2, the strut 5 includes a cylinder 6 with an open upper end and a
A first hydraulic chamber 6a and a second hydraulic chamber 6 are arranged vertically inside the cylinder 6 and are slidably arranged inside the cylinder 6.
The piston 7 is connected to the piston 7 and projects upward from the upper end opening of the cylinder 6. The lower end of the cylinder 6 is connected to the upper part of the wheel support member 3 via a bracket 9, while the upper end thereof is connected to the vehicle body 1 via a mount rubber 10. Further, the first and second hydraulic chambers 6a and 6b of the cylinder 6 are communicated with each other through an orifice 11 formed in the piston 7 so that oil can enter and exit from the first and second hydraulic chambers 6a and 6b. When the wheel 5 expands and contracts, that is, when the piston 7 slides vertically within the cylinder 6, the vertical vibration of the wheel 2 is damped by the effect of delaying oil inflow and outflow at the orifice 11.

In FIG. 1, reference numeral 12 designates an accure mulator that performs a spring action, and the interior of this accumulator 12 is divided by a diaphragm 12c into a gas chamber 12a and a hydraulic chamber 12b that oppose each other.
The gas chamber 12a is filled with nitrogen gas or the like. Hydraulic chamber 12b of this accumulator 12
is communicated with the second hydraulic chamber 6b of the cylinder 6 of the strut 5 via a communication conduit 13 and a hydraulic passage 14 formed in the piston rod 8 of the strut 5. This accumulator 12 transfers the pressure generated in the second hydraulic chamber 6b to the first hydraulic chamber 6a and transmitted to the hydraulic chamber 12b to the gas chamber 12.
It is configured to function as a gas spring that is supported by the compressive elasticity of the gas sealed in 2a. Further, a damping force valve 14 is provided in the middle of the communication pipe 13, and the damping force is made variable by adjusting the opening of this damping force valve 16.

The above-mentioned accumulator 12 of the above-mentioned communication pipe line 13
Between the damping force valve 15 and the right front wheel side pressure oil supply path 1
6 is connected, and this pressure oil supply path 16 is connected to 4
It is connected to one discharge port of a flow dividing valve 17 having two discharge ports. The other three discharge ports of this flow dividing valve 17 include a left front wheel side pressure oil supply path 18 which has the same function as the right front wheel side pressure oil supply path 16, a right rear wheel side pressure oil supply path 19, and a left rear wheel side pressure oil supply path. Supply paths 20 are connected to each other. The diversion valve 17 is connected by a pressure oil supply path 21 to an oil pump 22 that serves as a hydraulic drive source for the strut 5, which is a fluid actuator, and transfers the pressure oil from this pump 22 to the four pressure oils. The flow is divided into supply paths 16, 18, 19 and 20. The oil pump 22 is connected to the engine E via a drive belt 23 and is driven to follow the rotation of the engine E.

The pressure oil supply path 16 is provided with a leveling valve 24 which is an electromagnetic valve, and this leveling valve 24 supplies the pressure oil from the diversion valve 17 to the strut 5 while adjusting the amount thereof, and increases the vehicle height. This is to adjust the A drain passage 25 is connected to the pressure oil supply passage 16 between the diversion valve 17 and the leveling valve 24, and this drain passage 25 is provided with an unload valve 26 which is a solenoid valve.

The leveling valve 24 and unloading valve 26 are
Both are connected to a controller 27 composed of a microcomputer, etc., and the duty is not controlled by this controller 27, and the leveling valve 24 is operated at the pulse duration t ₁ in the pulse time T as shown in FIG. is opened, the unload valve 26 is closed, and the remaining time
At _t2 , unload valve 26 is configured to open and leveling valve 24 is configured to close. With this configuration, part of the pressure oil supplied from the diversion valve 17 is supplied to the strut 5 in an amount corresponding to time _t1 , while the remainder is drained in an amount corresponding to time _t2 . be done.

The controller 27 includes a manual switch 2 that outputs a target vehicle height signal _S0 indicating a desired vehicle height.
8, and a vehicle height sensor 29 that detects the actual vehicle height and outputs a vehicle height signal _S1 indicating the detected vehicle height. The controller 27 outputs the target vehicle height signal S ₀
In response to the vehicle height signal _S1 , the leveling valve 24 and the unloading valve 26 are controlled to open so that the vehicle height reaches the target vehicle height, especially when the vehicle is loaded. control the supply of
With this, the desired vehicle height is always achieved.

However, when a car repeatedly changes its posture such as rolling, diving, and skidding, the struts 5 operate, or expand and contract, a considerable number of times, causing a considerable amount of oil to leak from inside the struts 5, making it difficult to maintain the desired vehicle height. It becomes impossible to maintain the value.

Therefore, in the embodiment of the present invention, the strut 5 is provided with a running state detector 30 that detects the operation of the strut 5, that is, its expansion and contraction, and generates the posture change signal _S2 , and this detector 30 is connected to the controller 27. Connected. The controller 27 receives and counts the posture change signal _S2 from the running state detector 30, and when the number of signals _S2 reaches a predetermined value, opens the leveling valve 24 to supply pressure oil to the strut 5. replenish. How to replenish this pressure oil
Since the amount of pressure oil leaking from the strut 5 is approximately proportional to the number of times the posture changes, a predetermined amount of pressure oil may be replenished based on this number of times, or a predetermined amount of pressure oil may be replenished based on this number of times, or the target vehicle height may be achieved. You may also perform this while detecting with a vehicle height sensor.

In this manner, in the vehicle height adjustment device of the present invention, the struts 5 are periodically and automatically replenished with pressure oil, so that the vehicle height can always be maintained at the target vehicle height.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a vehicle height adjustment device for an automobile according to an embodiment of the present invention, and FIG. 2 is a detailed sectional view of a strut. FIG. 3 is a waveform diagram showing the pulse time T. 1...Vehicle body, 2...Wheels, 5...Struts,
25...Leveling valve, 27...Controller,
28...Manual switch, 29...Vehicle height sensor, 30...Running state detector.

Claims (1)

[Claims] 1. Pressurized fluid from a pump is supplied and discharged from the fluid actuator that is located between the vehicle body and the wheels and supports the vehicle body by switching the vehicle height adjustment valve, and the vehicle height is adjusted only in the event of a leakage of the pressure fluid or other abnormality. The vehicle height adjustment device includes a driving state detecting means that detects the number of expansion and contraction operations of a fluid actuator as each wheel moves up and down with respect to the vehicle body, and a vehicle height adjustment device that adjusts the vehicle height according to an output signal from the driving state detecting means. A vehicle height adjustment device for an automobile, comprising pressure fluid replenishment means for controlling a regulating valve to supply pressure fluid to the fluid actuator to compensate for leakage of pressure fluid from the fluid actuator due to operation of the fluid actuator.