JPS6148444B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air suspension device for an automobile.

In a so-called air suspension that uses an air spring that utilizes the volumetric elasticity of air sealed inside as a wheel suspension system for a car, the height of the vehicle can be raised by supplying air to the air sealed part of the air suspension. By discharging the enclosed air, the vehicle height can be lowered.

Therefore, the lower end of a telescopic member consisting of a combination of a cylinder and a rod slidably fitted into the cylinder is attached to the wheel support member side, the upper end is attached to the vehicle body member side, and the cylinder and rod are attached to the outer periphery of the telescopic member. An air chamber with air sealed inside is formed astride the cylinder so that the air sealed in the air chamber acts as a spring against the expansion and contraction movement of the expansion and contraction member accompanying the vertical movement of the wheel. A vehicle height sensor is provided in the air chamber to detect the relative positional relationship between the rods,
Vehicles that can adjust the vehicle height by controlling the air supply and exhaust into the air chamber based on the signal from the vehicle height sensor have already been developed (for example, Japanese Patent Laid-Open No. 120129-1982).
Publication No. 120130, Japanese Patent Application Laid-open No. 1983-120130, Japanese Patent Application Publication No. 1983
(See Publication No. 120131, etc.)

However, in the above-mentioned device, when the vehicle height is raised, the air capacity of the air chamber increases, the spring constant of the air decreases, and the spring becomes too soft.
This has the problem of reduced roll rigidity and poor riding comfort.

The present invention aims to address the above-mentioned conventional problems, and will be described below with reference to embodiments in the accompanying drawings.

In the figure, reference numeral 1 denotes a telescopic member consisting of a combination of a cylinder 2 and a rod 3 slidably fitted therein, and the lower part of the cylinder 2 is a bracket 2.
1 to a wheel side member (not shown), and the upper end of the rod 3 is connected to a vehicle body side member (not shown) via an elastic material 31 such as rubber.

A lower tank 5 is fixed to the outer periphery of the cylinder 2, a top tank 6 is fixed to the rod 3, and an air chamber 4 seals air around the outer periphery of the elastic member 1 by means of a diaphragm 7 that airtightly connects the lower tank 5 and the top tank 6. is formed.

Inside the air chamber 4, a helper 8 made of an elastic material such as rubber is attached to the rod 3 at its lower end surface 8.
a is attached to face the upper end surface of the cylinder 2 at a predetermined distance, and the lower end surface of the helper 8 comes into contact with the upper end surface of the cylinder 2 during pumping to prevent the elastic member 1 from bottoming out. However, in the present invention, the helper is configured to be vertically adjustable by a cylinder device 9 provided in the air chamber 4, and the relative dimension between the helper 8 and the cylinder 2 is kept constant by a signal from the helper position sensor 11. In addition, the diameter of the cylinder device 9 is made as large as possible, so that even if the vehicle height is changed, changes in the air capacity in the air chamber 4 are controlled to a minimum due to the operation of the cylinder device 9.

That is, the cylinder device 9 includes a cylinder portion 91 having a large diameter close to the effective diameter of the telescopic portion of the air chamber 4, that is, the effective diameter of the diaphragm 7 portion, and the cylinder portion 9.
A piston portion 9 slidably fitted within 1.
The cylinder part 91 is attached to the rod 3, and the upper part of the helper 8, which is slidably fitted to the rod 3, is fixed to the lower surface of the piston part 92. By supplying hydraulic pressure, the piston part 92 descends to lower the helper 8, and by discharging the hydraulic pressure in the cylinder part 91, the piston part 92 is raised by the air pressure in the air chamber 4, raising the helper 8. It is becoming possible to do this.

The oil pressure is controlled by a signal from a helper position sensor 11 which is a combination of a drive magnet 11a provided on the piston portion 92 and a magnetically sensitive switch 11b provided on the rod 3 side, for example, the cylinder portion 91.

That is, when driving in the low vehicle height state shown in the figure, for example, when a driving condition such as a bad road occurs that requires a higher vehicle height, a driving condition sensor (not shown) that detects the situation issues a signal, and the air chamber 4 Air is supplied to the rod 3, and the rod 3 is extended to raise the vehicle height. The high vehicle height position and the low vehicle height position are set by a vehicle height sensor 1 consisting of a drive magnet 12a provided on the cylinder 2 and a magnetically sensitive switch 12b provided on the rod 3 side.
This is done by 2.

When the above-mentioned signal for raising the vehicle height is issued, the control circuit of the helper position sensor 11 is switched to the lower position side, hydraulic pressure is supplied to the cylinder part 91, the piston part 92 is lowered, and the drive magnet 1
1a stops at a position corresponding to the low position setting portion of the magnetically sensitive switch 11b, and the helper 8 is lowered by the amount that the vehicle height is increased, that is, by the extension of the rod 3, and the relationship between the helper 8 and the cylinder 2 is adjusted. The height of the vehicle is kept approximately the same as when the vehicle height is low.

In this case, since the cylinder device 9 for helper adjustment is configured to have a large diameter that is almost close to the effective diameter of the telescopic portion of the air chamber 4, the increase in air volume in the high vehicle height state is mostly due to the downward movement of the piston portion 92. In other words, the increase in air volume at high vehicle heights is extremely small compared to when vehicle heights are low, and the spring constant also has favorable nonlinear characteristics as at low vehicle heights. It is possible to maintain roll rigidity and riding comfort in appropriate conditions.

In addition, by increasing the diameter of the cylinder device 9 for adjusting the helper, it is possible to bring about the advantage that a large load during pumping can be sufficiently withstood with a low oil pressure.

In addition to the above-mentioned embodiment, the helper position sensor 11 is provided with a driving magnet on either one of the piston part 92 and the cylinder 2 of the telescopic member 1, and a magnetically sensitive switch on the other, to determine the relative positional relationship between the piston part 92 and the cylinder 2. When the relative positional relationship is detected and exceeds a predetermined value, oil pressure may be supplied to the cylinder section 91, and when the relative positional relationship becomes below a predetermined value, the oil within the cylinder section 91 may be discharged.

As described above, according to the present invention, in an air suspension that can automatically control the vehicle height, the helper is moved and adjusted by a large-diameter cylinder device, and the relative position between the helper and the member to which the helper hits is always maintained at a predetermined value. It is possible to keep the change in the air volume in the air chamber to a small value that does not significantly affect the spring constant by operating the cylinder device for adjusting the helper position, and it is possible to This can bring about a great practical effect in that the spring characteristics can be kept at the optimum value regardless of the height, and the roll rigidity and riding comfort can always be maintained at an appropriate level.

[Brief explanation of the drawing]

The accompanying drawings are cross-sectional views showing embodiments of the present invention. 1... Telescopic member, 2... Cylinder, 3... Rod, 4... Air chamber, 8... Helper, 9...
Cylinder device, 91...Cylinder part, 92...Piston part, 11...Helper position sensor, 12...
Vehicle height sensor.

Claims (1)

[Claims] 1. An air chamber filled with air is formed around the outer periphery of a telescoping member consisting of a cylinder and a rod slidably fitted into the cylinder, and the lower part of the telescoping member is attached to the wheel side member and the upper part to the vehicle body side member. In addition, in the air suspension in which the vehicle height can be adjusted by supplying and exhausting air in the air chamber, a helper made of an elastic material is attached to the rod side of the telescoping member so that its tip faces the cylinder side. An air suspension device for an automobile, characterized in that the air suspension device for an automobile is configured to be able to adjust the movement of the telescopic member in relation to the cylinder side to maintain a predetermined value using a large-diameter cylinder device installed on the rod side within the air chamber. .