JPH0722805U - Pneumatic shock absorber - Google Patents

Abstract

(57) [Abstract] [Purpose] It is safe against air pressure failure, exerts a cushioning action in both the rebound and bounce directions of the wheel, and enables the roll rigidity to be adjusted. A cylinder end is connected to one of a suspension arm of a vehicle and an end of a stabilizer rod, and an outer end of a piston rod 12 is connected to the other. The piston rod 12 is slidably penetrated through a pair of upper and lower pistons 10 and 15 fitted in a cylinder 13. A spring 25 interposed between the pair of pistons 10 and 15 biases the pair of pistons 10 and 15 toward the intermediate flange 12a of the piston rod 12 and the retaining ring 14 at the inner end of the piston rod 12. The air pressure in the air chamber 24 between the pair of pistons 10 and 15 is adjusted from the outside.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a pneumatic shock absorber connected between an end of a stabilizer rod and a suspension arm that works to cancel the difference in height between left and right wheels, and more particularly to a pneumatic shock absorber capable of adjusting damping force. Is.

[0002]

[Prior art]

 In order to adjust the roll rigidity of the vehicle, it is common to add or subtract the damping force of the shock absorber or the spring constant of the suspension spring, but the configuration becomes complicated and expensive, and it is not suitable for mass vehicles. In the pneumatic shock absorber disclosed in Japanese Utility Model Publication No. 59-62008, the lower end of the cylinder is connected to the suspension arm, and the upper end of the piston rod is connected to the end of the stabilizer rod. Therefore, the air pressure in the cylinder chamber defined below the piston can be adjusted according to the running conditions of the vehicle. However, in the above-mentioned pneumatic shock absorber, it works only in the rebound direction of the wheels, and if the pneumatic system fails, the shock absorbing action may be lost, which may cause a dangerous situation in driving.

[0003]

[Problems to be solved by the device]

 In view of the above problems, an object of the present invention is to provide a pneumatic shock absorber that is safe against pneumatic pressure failure, exerts a buffering action in both the rebound and bound directions of the wheel, and can adjust the damping force. It is in.

[0004]

[Means for Solving the Problems]

 To achieve the above object, the structure of the present invention is a pneumatic shock absorber in which a cylinder end is connected to one of a vehicle suspension arm and an end of a stabilizer rod, and the other end is connected to an outer end of a piston rod. The piston rod is slidably penetrated through a pair of upper and lower pistons fitted in the piston, and a pair of pistons is retained by a spring interposed between the pair of pistons to prevent the intermediate flange of the piston rod and the inner end of the piston rod from coming off. The air chamber between the pair of pistons is filled with pressurized air.

[0005]

[Action]

 When the cylinder is pushed up as the wheel rebounds, the upper piston moves closer to the lower piston against the spring and air pressure inside the cylinder, absorbing the shock and suppressing the roll of the vehicle body. When the cylinder is pushed down as the wheel bounces, the lower piston moves closer to the upper piston against the spring and air pressure inside the cylinder, absorbing the shock and suppressing the roll of the vehicle body. .

[0006]

【Example】

 FIG. 1 is a front sectional view of a pneumatic shock absorber according to the present invention. The pneumatic shock absorber 4 is composed of a pair of upper and lower pistons 10 and 15 fitted inside a cylinder 13 and a piston rod 12 connecting the pair of pistons 10 and 15. In the cylinder 13, a spherical portion 19a of a mounting shaft 19 is fitted on a cylindrical portion 18 of a lower end wall, and a cup-shaped presser 22 is externally fitted to form a ball joint. The mounting shaft 19 is screwed into a screw hole of a suspension arm (not shown) and is fastened by a nut. The sliding portion of the ball joint is sealed by a boot 21, and the space between the lower end of the cylinder 13 and the suspension arm is covered by a protective cover 20.

The upper end of the cylinder 13 is closed by screwing an end wall 9 and is covered with a buffer cover 8. The air chamber 24 between the pair of pistons 10 and 15 houses a spring 25, and the inlet / outlet port 26a can be connected to an external air pressure source. Therefore, the inlet / outlet port 26a of the cylinder 13 is connected to the nipple 26.

A piston rod 12 slidably penetrating the end wall 9 and the pistons 10 and 15 has a retaining ring 14 as a retaining member locked at the lower end so that the piston 15 does not come off. Preferably, the piston 15 is integrally formed with a tubular portion 15a that projects to the upper and lower central portions of the cylinder 13. The piston rod 12 is integrally formed with the intermediate flange 12a, and when no external force is applied, the piston 10 is pressed against the intermediate flange 12a by the force of the spring 25, and the intermediate flange 12a is pressed against the end wall 9. The sliding parts of the pistons 10 and 15 with respect to the cylinder 13 and the sliding parts with respect to the piston rod 12 are sealed by elastic seal members.

The upper end portion of the piston rod 12 constitutes a ball joint by fitting the sphere portion 3 a of the mounting shaft 3 into the horizontally oriented cylinder portion 7. The sliding portion of the ball joint is sealed by the boot 6. The mounting shaft 3 is screwed into a screw hole at the end of a stabilizer rod (not shown), and is fastened by a nut.

Next, the operation of the pneumatic shock absorber according to the present invention will be described. Now, when the suspension arm together with the wheel on one side is pushed up by the projection on the road, the end wall 9 of the cylinder 13 separates from the intermediate flange 12a of the piston rod 12. The piston 15 regulated by the intermediate flange 12a relatively moves upward inside the cylinder 13. At this time, the air in the spring 25 and the air chamber 24 is compressed to absorb the impact from the wheel to the piston rod 12 and to prevent the piston 10 from approaching the piston 15 in the cylinder 13 relatively. suppress.

On the contrary, when the suspension arm together with the wheel on one side is pushed down by the depression of the road surface, the lower end wall of the cylinder 13 separates from the piston 15. The piston 15 restricted by the retaining ring 14 moves relatively upward in the cylinder 13. At this time, the air in the spring 25 and the air chamber 24 is compressed, absorbs the impact from the wheel to the piston rod 12, works to suppress the relative approach of the piston 15 in the cylinder 13 to the piston 10, and the roll of the vehicle body. Suppress.

As shown in FIG. 2, the air pressure in the air chamber 24 is controlled by the electronic control unit 32 based on detection signals of vehicle speed by each sensor 31, vehicle height change of each wheel, longitudinal acceleration acting on the vehicle body, and lateral acceleration. To drive the electromagnetic switching valve 34 to supply the pressurized air in the air tank 33 to the air chamber 24 of the pneumatic shock absorber 4 via the electromagnetic switching valve 34 to increase the air pressure in the air chamber 24 or If the air is discharged to the atmosphere through the electromagnetic switching valve 34 and the air pressure in the air chamber 24 is lowered, the damping force of the pneumatic shock absorber 4 suitable for the running condition can be obtained and a comfortable ride can be obtained.

[0013]

[Effect of device]

 According to the present invention, as described above, when one of the left and right wheels moves up and down, one of the pair of upper and lower pistons approaches the other inside the cylinder of the pneumatic shock absorber, which causes a difference in height between the left and right wheels. The air and the air in the cylinder's air chamber are compressed at the same time, absorbing the impact from the wheels and exerting the roll rigidity of the vehicle body.

Since a pair of pistons move relative to each other inside the cylinder, a large stroke and rigidity can be obtained with a limited cylinder size. In particular, a large roll rigidity can be obtained by the region where the air pressure bears the load and the region where the stabilizer rod bears the load.

By changing the air pressure of the air chamber between the pair of pistons, an arbitrary roll rigidity can be obtained, and since a hydraulic pump or an oil tank is not required, it is more economical than a hydraulic shock absorber. .

Even if the air pressure is lost, the spring between the pair of pistons maintains the roll rigidity, so that there is no problem in traveling.

[Brief description of drawings]

FIG. 1 is a front sectional view of a pneumatic shock absorber according to the present invention.

FIG. 2 is a schematic configuration diagram of a pneumatic shock absorber that controls the air pressure.

[Explanation of symbols]

10: Piston 12: Piston Rod 12a: Intermediate Flange 13: Cylinder 14: Stop Ring 15: Piston 24: Air Chamber 25: Spring

Claims (1)

[Scope of utility model registration request] 1. A pneumatic shock absorber in which a cylinder end is connected to one of a suspension arm of a vehicle and an end of a stabilizer rod, and an outer end of a piston rod is connected to the other end of the suspension rod of the vehicle. The piston rod is slidably passed through the piston, and a pair of pistons are urged by the spring interposed between the pair of pistons to the intermediate flange of the piston rod and the retaining member at the inner end of the piston rod. A pneumatic shock absorber characterized in that an air chamber between pistons is filled with pressurized air.