JPS61261114A - Vehicle level adjusting device - Google Patents

Abstract

PURPOSE:To enhance the control and running stability of a vehicle, by providing a main fluid chamber for adjusting the level of the vehicle and a sub-fluid chamber connected to the main chamber through a shut-off valve, at each of four wheels such that if the fluid pressure in the sub-fluid chamber is below a predetermined value, a shut-off valve is closed. CONSTITUTION:If the fluid pressure in four subtanks 11a through 11d exceed a predetermined value, their respective circuits are opened by pressure switches 17a through 17d, respectively, and a valve closing means 20 delivers no control signal to solenoids 19g through 19j in spring constant changing valves 12g through 12j. However, when air leaks from any one of the subtanks 11a through 11d, for example, the subtank 11a and therefore, the fluid pressure lowers, the associated pressure switch 17a delivers a valve close signal DPa to the valve closing means 20 so that the valve closing means 20 closes the corresponding spring constant changing valve 12g to shut off the passage between a main air chamber 4 and subtank 11a. Thus, it is possible to enhance the control and running stabilities of the vehicle.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention enables the vehicle height to be increased or decreased by controlling the internal pressure of a main fluid chamber interposed between the body and wheels of a vehicle such as an automobile. The present invention relates to a vehicle height adjustment device, particularly its failsafe mechanism.

[Conventional technology]

As a conventional vehicle height adjustment device, for example, Japanese Patent Application Laid-Open No. 58-4
There is one as described in the 9506 publication.

These are: a vehicle height detector that generates a signal corresponding to the height of the vehicle; a drive means that controls the vehicle height up and down; a control circuit that energizes and deenergizes the drive means in response to signals from the vehicle height detector; Those with the following are described.

[Problem that the invention seeks to solve]

However, in such conventional vehicle height adjustment devices, the drive means for increasing or decreasing the vehicle height has a configuration in which the air spring constant cannot be changed.
It has not been possible to change the vibration isolation/distribution characteristics of the suspension itself against vibrations caused by changes in road surface irregularities, unbalanced tires, etc., and it has not been possible to improve the vibration riding comfort of the vehicle.

Therefore, in order to improve the above-mentioned vibration riding comfort, an auxiliary fluid chamber is provided in communication with the fluid chamber of the drive means via an on-off valve, and the opening and closing of the on-off valve is controlled to connect only the fluid chamber and the auxiliary fluid chamber to this. By changing the volume in two stages (1 and 2), and by changing the volume to obtain two levels of air spring constant (high and low), the air spring constant can be changed depending on the road surface condition etc. to reduce vibration multiplication. It can improve your comfort.

In this case, the above-mentioned auxiliary fluid chamber is installed, for example, one in relation to each fluid chamber of the four wheels, and when each opening/closing valve is opened and the fluid chamber and the auxiliary fluid chamber are in communication with each other, When one sub-fluid chamber is damaged and its pressure decreases, the fluid in the fluid chamber connected to it is exhausted from the sub-fluid chamber to the atmosphere, and the pressure in the main fluid chamber decreases, causing the air spring constant of the four wheels to decrease. There is a problem in that an imbalance occurs, which impairs steering stability and driving stability.

[Means for Solving the Problems] The present invention has been made by focusing on such conventional problems, and includes an intervening device between at least one wheel and the vehicle body that can increase or decrease the vehicle height. the same number of main fluid chambers as the wheels;
The same number of sub-fluid chambers as the main fluid chamber are communicated with this main fluid chamber via on-off valves, and the same number of pressure detectors as the sub-fluid chambers output pressure detection signals according to the pressure in the sub-fluid chamber. and a valve closing means that outputs a control signal to the opening/closing valve to close the opening/closing valve when the fluid pressure in the auxiliary fluid chamber falls below a predetermined value based on the pressure detection signal of the pressure detector. The present invention is characterized in that the above-mentioned problems are solved by configuring a vehicle height adjustment device.

[Effect]

Therefore, in the present invention, at least one of the vehicles such as an automobile
An auxiliary fluid chamber is connected via an on-off valve to a main fluid chamber that is installed in relation to a wheel and whose vehicle height can be increased or decreased by the same number as the wheels, and the fluid pressure in the auxiliary fluid chamber is detected by a pressure detector and the pressure is measured. A detection signal is supplied to the valve closing means, and when the fluid pressure is lower than a predetermined value, a closing signal is output from the valve closing means to the opening/closing valve to close the opening/closing valve, thereby preventing a drop in pressure in the main fluid chamber. To ensure steering stability and running stability of a vehicle by minimizing imbalance in air spring constants of four wheels.

〔Example〕

The present invention will be explained below based on illustrated embodiments.

FIG. 1 and FIG. 2 are diagrams showing an embodiment of the present invention.

First, to explain the configuration, as shown in FIG. 1, 1a is a vehicle height adjustment actuator for the front left wheel, 1b is a vehicle height adjustment actuator for the front right wheel, 1c is a vehicle height adjustment actuator for the rear left wheel, 1d is a vehicle height adjustment actuator for the rear right wheel, and these vehicle height adjustment actuators 1
a to 1d are composed of a shock absorber 2 and an air chamber 4 which is a main fluid chamber provided above the shock absorber 2 and defined by a rubber-like elastic body 3 such as rubber.

The upper ends of the piston rod 5 and the rubber-like elastic body 3 of the shock absorber 2 are attached to the vehicle body 6, and
The lower end portions of the shock absorbers 2 are respectively attached to axles 7 that rotatably support wheels (not shown), and in this way, the four vehicle height adjustment actuators 1a to 1d adjust the distance between the four wheels and the vehicle body 6. An interposition is installed in between that allows the vehicle height to be increased or decreased.

Furthermore, the air chambers 4 of the vehicle height adjustment actuators 1a to 1d store a fluid pressure source 9 and air, which is a high-pressure fluid, generated by the fluid pressure source 9 via a communication hole 8 provided in the piston rod 5. It communicates with the main tank 10 and sub-tanks 11a-lid, which are four sub-fluid chambers provided corresponding to the vehicle height adjustment actuators 1a-1d, and there are two points in these communication passages. 10 opening/closing valves consisting of two-position, spring-offset electromagnetic switching valves
/7" 12a to 12j are provided. The content of the ten on-off valves 12a to 12j is that the on-off valve 12a provided near the discharge port of the fluid pressure source 9 is for exhaust pulp,
An on-off valve 12b provided at the outlet of the main tank 10
is an air supply valve, and four on-off valves 12c, 12d, 12e, and 12f provided at each branch part on the front wheel side and the rear wheel side.
are supply and exhaust valves, air chamber 4 and 4 sub-tanks lla~
4 on-off valves 1 each provided between the lid and the lid
2g, 12h, 12i, and 12j are spring constant changing valves.

The ten on-off valves 122 to 12j are input/output ports, a processing unit (CPU), and a RAM.

The exhaust valve 12 is driven to open and close by a control signal output from a control circuit (not shown) having a microcomputer equipped with a storage device such as a ROM.
a, air supply valve 12b, and four air supply and exhaust valves 12c to 1
2f, on the other hand, air from the fluid pressure source 9 is supplied to the air chambers 4 of each of the vehicle height adjustment actuators 1a to 1d through the main tank 10, and thereby the air chambers 4 The vehicle height is continuously increased by increasing the fluid pressure within the air chamber 4, and on the other hand, the vehicle height is continuously lowered by removing air from the air chamber 4 to lower the fluid pressure within the air chamber 4.

In addition, by controlling the opening and closing of the four spring constant changing valves 12g to 12j with the four supply and exhaust valves 12c to 12f closed, the volume of the air chamber 4 alone and the volume of the subtanks lla to lid can be changed. The volume changes in two stages, resulting in two levels of high and low air spring constants.

Therefore, these vehicle height adjustment actuators 1a to 1d can steplessly increase or decrease the vehicle height while changing the air spring constant to two levels, the normal position and the low position, at each vehicle height position.

The fluid pressure source 9 includes a near compressor 9a and an electric motor 9b. A motor drive relay 13 is connected to the electric motor 9b, and the pressure is output from a pressure switch 14 provided on the supply side of the main tank 10. The motor drive relay 13 is closed by the drive signal, and as a result, a drive current is supplied from a power source (not shown) to the electric motor 9b, and the fluid pressure source 9 is driven to discharge air. 15 is for removing moisture from the air discharged from the fluid pressure source 9.
The first air dryer, 16, is the main tank 10
This is a check valve to prevent backflow of air from the inside.

Further, each of the four sub-tanks lla-lid is provided with one pressure switch 17a-17d, which is a pressure detector that individually detects the internal fluid pressure. Each pressure switch 17a to 17d closes its circuit and outputs a pressure detection signal D P a - D P d when the internal fluid pressure decreases to a predetermined value or less.

These pressure detection signals DPa to DPd are supplied to the valve closing means 20, which is constituted by, for example, four relay circuits provided corresponding to each pressure switch, seven switches 17a to 17d.

The output side of the valve closing means 20 is connected to four air chambers 4 that are individually interposed between the four air chambers 4 and the four sub-tanks lla to lid.
Spring constant change spring 12g~1? j electromagnetic solenoids 19g to 19j.

Next, the effect will be explained.

Now, the fluid pressure in the four sub-tanks lla to lid is
Assuming that each pressure is maintained higher than a predetermined value, the four pressure switches 17a to 17d that detect the pressure thereof maintain their respective circuits open. Therefore, each pressure switch 17a-17d
Pressure detection signal DPa supplied to the valve closing means 20 from
-DPd is an open signal indicating that the fluid pressure in each sub-tank lla to lid is equal to or higher than a predetermined value, so the pulp closing means 20 sends four spring constant changing valves 12g to 1.
A drive current, which is a control signal, is supplied to each electromagnetic solenoid 19g to 19j of 41.2j. do not have. Therefore, each spring constant changing valve 12g to 12j is maintained in its previous state.

Here, for example, if an air leak occurs in the front left sub-tank Ila and the fluid pressure in the sub-tank Ila becomes lower than a predetermined value, the pressure detection signal DPa supplied from the pressure switch 17a to the pulp closing means 20 The front left spring constant changing valve 1 changes from the pulp closing means 20 to a closing signal indicating that the fluid pressure is below a predetermined value.
A drive current is supplied to the 2g electromagnetic solenoid 19g.

As a result, the spring constant changing valve 12g is switched to the closed operating position, and the air chamber 4 of the front left vehicle height adjustment actuator 1a and the sub-tank lla paired therewith are cut off.

As a result, the fluid in the air chamber 4 is prevented from being discharged into the atmosphere through the sub-tank 11a, and a decrease in the fluid pressure in the air chamber 4 can be suppressed to a minimum. Therefore,
It is possible to minimize the imbalance in the air spring constants between the four air chambers 4 provided independently in the four wheels, and it is possible to ensure the steering stability and running stability of the vehicle.

In addition, a failure alarm means is provided to warn that a failure has occurred in one or more of the sub-tanks Ila to lid, and the failure alarm means is activated at the same time as the spring constant changing valve is driven by the output signal of the valve closing means 20. By doing so,
It is possible to make the driver or the like recognize the failure of the sub-tank visually, audibly, etc., and the failure can be promptly dealt with.

Furthermore, in the above embodiment, air is used as the fluid introduced into both the main and sub fluid chambers to increase or decrease the vehicle height, but it goes without saying that other gases may also be used. You may make it use together. Furthermore, although a total of four main fluid chambers are interposed between the four wheels and the vehicle body, one for each, the present invention can be realized as long as at least one main fluid chamber is interposed between at least one wheel. be able to.

[Effects of the Invention] As described above, according to the present invention, there are as many main fluid chambers as the wheels interposed between at least one wheel and the vehicle body so as to be able to increase or decrease the vehicle height; auxiliary fluid chambers of the same number as the main fluid chamber connected to the main fluid chamber via on-off valves;
The number of pressure detectors is the same as that of the sub-fluid chamber and outputs a pressure detection signal according to the pressure in the sub-fluid chamber, and the pressure sensor opens and closes when the fluid pressure in the sub-fluid chamber is lower than a predetermined value based on the pressure detection signal of the pressure detector. The vehicle height adjustment device is configured to include a valve closing means for outputting a control signal to the valve to close the opening/closing pulp. Therefore, even if fluid leaks from one or more sub-fluid chambers due to damage, etc., the pressure drop in the main fluid chamber paired with the sub-fluid chamber can be suppressed. Imbalance in spring constant can be minimized. Therefore, it is possible to suppress changes in the toe angle and increase in steering force caused by a pressure drop in some of the main fluid chambers, thereby achieving the effect that the steering stability and running stability of the vehicle can be ensured.

[Brief explanation of drawings]

FIG. 1 is a system explanatory diagram showing an embodiment of the present invention.

Claims (1)

[Claims] A main fluid chamber of the same number as the wheels, which is interposed between at least one wheel and the vehicle body so that the vehicle height can be increased or decreased, and the same number of main fluid chambers as the main fluid chambers communicated with the main fluid chamber via an on-off valve. an auxiliary fluid chamber, a number of pressure detectors equal to the number of auxiliary fluid chambers that output pressure detection signals corresponding to the pressure within the auxiliary fluid chamber, and a fluid pressure within the auxiliary fluid chamber based on the pressure detection signals of the pressure detectors. A vehicle height adjustment device comprising: valve closing means that outputs a control signal to the on-off valve to close the on-off valve when the on-off valve is lower than a predetermined value.