JPS61184108A - Car height regulating apparatus for automobile - Google Patents

Abstract

PURPOSE:To hole the proper car height and attitude of a car body even when turning by providing a roll decision means and a means for receiving a signal from the roll decision means to control the car height regulation speed in switching controller for car height regulation valve. CONSTITUTION:The wheel 2 is supported rotatably by a supporting member 3 the upper end section 3b of which is coupled through a hydraulic actuator for regulating the car height or a strut 5 to the body 1. A controller 27 will receive a target car height signal S0 from a manual switch 28 and a car height signal S1 from a car height sensor 29 to execute opening control of a levelling valve 24 thus to control pressure oil supply to the strut 5 and to regulate the car height. Here, a steering angle signal S3 from a steering angle sensor 30 and a car speed signal S4 from a car speed sensor 31 are fed to the controller 27 to decide the roll condition. If the roll is high, it is controlled to lower the car height regulating speed.

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) Generally, automobiles are sometimes equipped with a vehicle height adjustment device to change the vehicle height depending on the driving condition.

Conventionally, vehicle height adjustment devices for automobiles supply and discharge fluid from a pump, such as hydraulic oil, to and from a fluid actuator that is located between the vehicle body and the wheels and supports the vehicle body by switching a vehicle height adjustment valve. Vehicle height adjustment systems are known, and the vehicle height adjustment switching control described above is usually carried out by
This is done by the controller based on a comparison between the vehicle height signal from the vehicle height detector and the target vehicle height signal from the target vehicle height setting device.

The vehicle height adjustment by the vehicle height adjustment device operates even when the vehicle body is tilted, for example, when turning, correcting the tilt of the vehicle body and improving ride comfort. However, the vehicle height adjustment device adjusts the vehicle height by supplying and discharging pressure fluid from the pump to the fluid actuator by switching the vehicle height adjustment valve, so it takes a long time to complete the vehicle height adjustment. A predetermined amount of time is required, and therefore, when making an extremely sharp turn, the vehicle height adjustment continues even if the vehicle returns to a steady state of operation, that is, a straight-ahead state. In such a state, the vehicle tilts even though it is not in a steady state of operation, causing extreme discomfort to the occupants.

For this reason, Japanese Patent Publication No. 54-6785 and Japanese Unexamined Patent Publication No. 53-1989
The vehicle height adjustment device disclosed in Publication No. 51823 detects and determines that the vehicle is turning by some means, and stops the vehicle height adjustment by the vehicle height adjustment device when turning, thereby eliminating the above drawbacks. It has been resolved.

(Problem to be solved by the invention) However, if the vehicle height adjustment is always stopped when the vehicle turns, the vehicle will remain tilted for a long distance when driving on a long spiral road. This is not desirable.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a vehicle height adjustment device for an automobile that can maintain a suitable vehicle height and body posture not only during steady driving but also during sharp and slow turns. be.

(Structure of the Invention) The present invention provides vehicle height adjustment that adjusts the vehicle height by supplying and discharging pressurized fluid from a pump to and from a fluid actuator that is located between the vehicle body and the wheels and supports the vehicle body by switching a vehicle height adjustment valve. The vehicle height adjustment device includes a controller that switches and controls the vehicle height adjustment valve based on a comparison between a vehicle height signal indicating an actual vehicle height and a target vehicle height signal indicating a target vehicle height, the controller includes a roll determining means for determining the roll state in response to a signal from a sensor that detects the turning state of the vehicle, and a vehicle height adjustment speed for receiving the output of this determining means and outputting a signal for controlling the vehicle height adjustment speed. The invention is characterized in that it has a control means. The signal that controls the vehicle height adjustment speed may be a signal that repeatedly switches the vehicle height adjustment valve.

(Function) With the above-described configuration, the vehicle height adjustment device of the present invention makes the vehicle height adjustment speed slower than the vehicle height adjustment speed during steady driving when the vehicle rolls, and also reduces the speed. If the vehicle height adjustment speed is changed according to the degree of roll, that is, if the degree of roll is large, the vehicle height adjustment speed is made relatively slow, and when the degree of roll is small, the vehicle height adjustment speed is made relatively fast, then when the degree of roll is large, the vehicle height adjustment speed is made relatively fast. When turning, the vehicle height is only slightly adjusted; on the other hand, when turning slowly with a small degree of roll, the vehicle height can be adjusted to the desired level.

(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 an upper end 3b connected to the vehicle body 1 via a strut 5 as a fluid actuator for adjusting vehicle height. The movement of the wheel 2 in the vehicle width direction is restricted by the lower arm 4, and the vertical vibration of the wheel 2 is absorbed by the strut 5.

As shown in FIG. 2, the strut 5 includes a cylinder 6 with an open upper end, and first hydraulic chambers 6a that are movably disposed inside the cylinder 6 and are vertically arranged inside the cylinder 6. and a piston 7 forming a second hydraulic chamber 6b;
A piston rod 8 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 IO.

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 moves vertically within the cylinder 6, the vertical vibration of the wheel 2 is damped by the effect of delaying the extraction and insertion at the orifice 11.

In FIG. 1, reference numeral 12 designates an accumulator 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.

The hydraulic chamber 12b of the accumulator 12 is communicated with the second hydraulic chamber 6b of the cylinder 6 of the strut 5 via a communication pipe 13 and a hydraulic passage 14 formed in the piston rod 8 of the strut 5. This accumulator 12 functions as a gas spring that receives the pressure generated in the second hydraulic chamber 6b or the first hydraulic chamber 6a and transmitted to the hydraulic chamber 12b by the compressive elasticity of the gas sealed in the gas chamber 12a. It is configured to perform. 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 15.

A right front wheel side pressure oil supply line 16 is connected between the accumulator 12 and the damping force valve 15 of the communication line 13, and this pressure oil supply line 16 is connected to a branch valve 17 having four discharge ports. is connected to one discharge port of. 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 the pressure oil from this pump 22 is transferred to the four pressure oil supply paths. 16, 18, 19 and 20. The oil pump 22 is connected to the engine via a drive belt 23 and is driven to follow the rotation of the engine E.

The pressure oil supply path 16 includes a leveling valve 2 which is a solenoid valve.
4 is provided, and this leveling valve 24 adjusts the amount of pressure oil from the flow dividing valve 17 while also controlling the strut 5.
The vehicle height is adjusted by supplying the vehicle with the vehicle. The above diverter valve 17
A drain passage 25 is connected to the pressure oil supply passage 21 between the leveling valve 160 and the leveling valve 160, and the drain passage 25 is provided with an unload valve 26 which is a solenoid valve.

Both the leveling valve 24 and the unloading valve 26 are connected to a controller 27 composed of a microcomputer or the like, and the duty ratio is controlled by the controller 27, so that the pulse at the pulse time T is as shown in FIG. At a duration t, the leveling valve 24
is opened and the unload valve 26 is closed, while during the remaining time t2, the unload valve 26 is opened and the leveling valve 24 is closed. 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 remaining part is drained in an amount corresponding to time t2. . Therefore, if the width of the time t1 is increased, that is, if t+/T is increased, the amount of pressure oil supplied to the strut 5 per unit time increases, and the vehicle height adjustment speed becomes faster. If the width of t is made smaller, that is, t
If +/T is made smaller, the amount of pressure oil supplied to the strut 5 per unit time will be reduced, resulting in a slower vehicle height adjustment speed. The controller 27 is also connected to the damping force valve 15, and adjusts the opening degree of the damping force valve 15 as necessary to adjust the damping force.

The controller 27 receives a target vehicle height signal S to set a desired vehicle height. A manual switch 28 that outputs a vehicle height, and a vehicle height sensor 29 that detects the actual vehicle height and outputs a vehicle height signal S indicating the vehicle height are connected. The controller 27 receives the target vehicle height signal S.

In response to the vehicle height signal S1, the leveling valve 24 is controlled to open and the supply of pressure oil to the struts 5 is controlled so that the vehicle height reaches the target vehicle height, especially when the vehicle is loaded or rolled. . This always achieves the desired vehicle height.

However, if the vehicle height is adjusted in the same way as in normal situations when the vehicle rolls, the above-mentioned problem occurs. Therefore, in the present invention, the roll state is determined and the vehicle height is adjusted in accordance with the roll state to improve steering stability.

Therefore, the controller 27 includes a steering angle sensor 30 that detects the rotation angle of a steering wheel (not shown), that is, a steering angle, and outputs a steering angle signal s3 indicating this steering angle, and a steering angle sensor 30 that detects the vehicle speed and outputs a steering angle signal s3 indicating this steering angle. A vehicle speed sensor 31 that outputs a vehicle speed signal S4 indicating the vehicle speed is connected thereto, and a control map M for controlling the vehicle height adjustment speed according to the roll state as shown in FIG. 4 is stored. controller 27
determines the roll state based on the steering angle signal S and the vehicle speed signal S, and converts this roll state into the control map M.
In view of this, when the roll is large, the vehicle height adjustment speed is reduced, and when the roll is small, the adjustment speed is increased.

(Effects) As explained above, according to the present invention, when the degree of roll is large, the vehicle height adjustment speed is made relatively slow.
When returning to steady driving in a short period of time, such as when making a sharp turn with a large degree of roll, only a small amount of vehicle height adjustment is performed, which reduces the need for the vehicle to tilt when returning to steady driving. .

In addition, when the degree of roll is small, it is likely that the vehicle will be turning for a long time, and in this case, the vehicle height should be adjusted quickly to bring the vehicle body to the ideal condition and maintain a good driving posture during long turns. It is said that

[Brief explanation of drawings]

FIG. 1 shows the vehicle height of an automobile according to an embodiment of the present invention.
A block diagram of the adjustment device, Figure 2 is a detailed cross-sectional view of the strut, Figure 3 is a diagram showing the pulses used to control the leveling valve, and Figure 4 is a diagram showing the vehicle height adjustment speed according to the roll state. It is a diagram showing a map. l...Vehicle body, 2...Wheels, 5...
... Strut, 25 ... Leveling valve, 27 ... Controller, 28 ...
...Manual switch, 29...Vehicle height sensor, 30...Rudder angle sensor, 31...
...Vehicle speed sensor Fig. 3 Fig. 4

Claims (2)

[Claims] (1) A vehicle height adjustment device that adjusts vehicle height by supplying and discharging pressurized fluid from a pump to a fluid actuator that supports the vehicle body between the vehicle body and wheels by switching the vehicle height adjustment valve. The controller includes a controller that controls switching of the vehicle height adjustment valve based on a comparison between a vehicle height signal indicating an actual vehicle height and a target vehicle height signal indicating a target vehicle height, and the controller controls switching of the vehicle height adjustment valve based on a comparison between a vehicle height signal indicating an actual vehicle height and a target vehicle height signal indicating a target vehicle height. and a vehicle height adjustment speed control means that receives the output of the roll determination means and outputs a signal for controlling the vehicle height adjustment speed. An automobile vehicle height adjustment device characterized by: (2) The vehicle height adjustment device for an automobile according to claim (1), wherein the signal for controlling the vehicle height adjustment speed is a signal for repeating switching of the vehicle height adjustment valve.