JPS61184107A - Car height regulating apparatus for automobile - Google Patents

Abstract

PURPOSE:To hold proper car height and attitude of body even when turning by providing a roll decision means and a control means for producing only a car height up signal upon receipt of an output from the roll decision means to switching controller for car height regulation valve. CONSTITUTION:The wheel 2 is supported rotatably by a supporting member 3 the upper end of which 3b is coupled through a strut 5 serving as a hydraulic actuator for regulating the height of car 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. The controller 27 is further provided with a steering angle signal S3 and a car speed signal S4 from a steering angle sensor 30 and a car speed sensor 31. If the rolling is higher than predetermined level, the car height down signal is cut to produce only the car height up signal.

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 switching control for vehicle height adjustment is usually performed by a controller that compares a vehicle height signal from a vehicle height sensor with a target vehicle height signal from a target vehicle height setting device. It is based on

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 device outputs a vehicle height up signal or a vehicle height down signal based on a comparison between a vehicle height signal indicating the actual vehicle height and a target vehicle height signal indicating the target vehicle height, and controls the vehicle height adjustment valve. 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 controller for reducing the vehicle height when receiving the output of the roll determining means. The present invention is characterized in that it has a control means that cuts the signal and outputs only the vehicle height increase signal.

(Operation/Effect) The vehicle height adjustment device of the present invention has the above-described configuration, and when the vehicle rolls, the vehicle height is prohibited from being lowered and only the vehicle height is increased, so that the vehicle height can be returned to normal operation. In some cases, it is sufficient to simply remove the pressure oil supplied to the actuators, which allows the vehicle to quickly return to its normal position, thereby suppressing undesirable vehicle height fluctuations after the end of the roll, and reducing vehicle height during the roll. Adjustments can be made.

Furthermore, when vehicle height adjustment is prohibited when vehicle roll occurs as in the conventional device described above, when driving on a road with many curves such as a mountain road, the vehicle height may drop due to oil leakage. Since the device adjusts the height of the vehicle, pressure oil is supplied and the vehicle height can be prevented from lowering.

(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 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 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. 11, reference numeral 12 indicates 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 Akinimulator 12 acts 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 12B. It is configured to perform the functions of 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 path 16 is connected between the akinimulator 12 and the damping force valve 15 of the communication pipe 13, and this pressure oil supply path 16 has a branched flow path with four discharge ports. It is connected to one outlet of the valve 17. 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 E 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 supplies the pressure oil from the flow dividing valve 17 to the strubbed 5 while adjusting the amount thereof, thereby adjusting the vehicle height. A drain path 2 is provided in the pressure oil supply path 21 between the diverter valve 17 and the leveling valve 16.
5 is connected, and this drain path 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. During the duration t1, the leveling valve 24 is open and the unloading valve 26 is closed, while during the remaining time t2, the unloading valve 26 is open 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. . 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 includes a manual switch 28 that outputs a target vehicle height signal So to indicate a desired vehicle height, and a vehicle height sensor 29 that detects the actual vehicle height and outputs a vehicle height signal S1 indicating the vehicle height. It is connected. controller 27
is the target vehicle height signal S mentioned above.

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 is connected that outputs a vehicle speed signal S indicating the vehicle speed.

The controller 27 determines the roll state based on the steering angle signal S and the vehicle speed signal S4, and then determines whether or not this degree of roll is greater than a certain predetermined degree of roll. When this determination is YES, the vehicle The high-level down signal is cut and only the vehicle height up signal is output. Therefore,
When the vehicle rolls beyond a certain predetermined value, the vehicle height is not adjusted on the inner wheel side where the vehicle height increases, but only the outer wheel side where the vehicle height decreases, that is, the vehicle height is increased. As a result, it is possible to adjust the vehicle height to a certain extent even during a roll, while preventing the vehicle from unnaturally tilting at the end of the roll.

[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. FIG. 2 is a detailed sectional view of a strut. FIG. 3 is a diagram showing pulses used to control a leveling valve. .

Claims (1)

[Claims] This is 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. and a target vehicle height signal indicating the target vehicle height, the controller outputs a vehicle height up signal or a vehicle height down signal to switch and control the vehicle height adjustment valve. The controller includes a roll determining means that determines the roll state by receiving a signal from a sensor that detects the turning state of the vehicle, and when receiving the output of the roll determining means, cuts a vehicle height down signal and outputs a vehicle height up signal. A vehicle height adjustment device for an automobile, characterized in that it has a control means for outputting only a.