JPH0536243B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a vehicle suspension system used in a suspension mechanism of an automobile or the like.

[Technical background of the invention and its problems]

An example of a conventional vehicle suspension system is a strut-type suspension system that includes a cylinder with an oil chamber inside, and a hollow rod that is slidably inserted into the cylinder and has an oil chamber and a gas chamber inside. It has been known. In this product, a seal part is provided in the sliding part between the cylinder and the hollow rod to seal oil and gas, but this seal part is required to have a high pressure resistance because the pressure inside the cylinder is applied. Not only did the sliding resistance increase, but if the sliding part of the rod or the sealing member were damaged, oil or gas could leak from the sealing part. A suspension system has also been proposed in which a main gas chamber is provided inside the cylinder and a sub-chamber is installed outside the cylinder separately from the cylinder, and the main gas chamber and the sub-chamber are communicated with each other via a conduit. In a suspension system that is equipped with a separate sub-chamber, the sub-chamber and cylinder are separated, which not only increases the length of the pipe line, but also requires a switching valve to be installed in the middle of the pipe line to communicate and shut off the pipe line. In case,
In addition to the subchamber, installation space for the switching valve must also be secured outside the cylinder or rod, which poses problems such as making it difficult to achieve compactness.

[Purpose of the invention]

The present invention has been made based on the above circumstances, and its purpose is to prevent gas from leaking to the outside even if it leaks from the seal part, to reduce the withstand pressure of the seal part, and to prevent gas from leaking from the gas spring. It is an object of the present invention to provide a suspension system for a vehicle that can change constants and can be constructed relatively compactly.

[Summary of the invention]

The gist of the present invention is to provide a cylinder having an oil chamber inside, a hollow cylinder slidably inserted into the cylinder and having an oil chamber inside and a main gas chamber filled with compressed gas above the oil chamber. a rod; a seal portion that seals between the cylinder and the hollow rod;
a gas chamber outer cylinder provided outside the hollow rod concentrically with the hollow rod; a sub-gas chamber provided between the inner surface of the gas chamber outer cylinder and the outer surface of the hollow rod and filled with the compressed gas; A gas passage that communicates the main gas chamber and the auxiliary gas chamber, a switching valve and a switching drive source capable of switching communication and cutoff of the gas passage, and one end fixed to the cylinder and the other end reversed. and a bellows frame-shaped gas seal member fixed to the gas chamber outer cylinder to seal the sub-gas chamber.

According to the above configuration, even if gas leaks from the seal, the gas is collected in the auxiliary gas chamber and will not leak to the outside.Moreover, the gas pressure in the auxiliary gas chamber can be applied to the seal from the outside. is applied, and the differential pressure at the seal part is small. Therefore, the sealing member may have a low pressure resistance, and the sliding resistance of the sealing portion can be reduced.

Furthermore, the suspension system of the present invention can switch the capacity of the gas chamber that functions as a gas spring between two types, large and small, by operating the switching valve, and can change the gas spring constant according to the capacity of the gas chamber. can. In this suspension system, the auxiliary gas chamber concentrically surrounds the outside of the main gas chamber in the hollow rod on the upper side of the hollow rod, so the gas passage that communicates the main gas chamber and the auxiliary gas chamber with each other is short. Moreover, it requires only a simple passage, and the space inside the rod can be used when installing a switching valve in the middle of the gas passage or arranging an actuator (switching drive source) for driving the valve body, making it easy to install these. be.

[Embodiments of the invention]

A first embodiment of the present invention will be described below with reference to FIG. In the figure, 1 is a cylinder, and inside this cylinder 1, an oil chamber 2 is provided. Further, a knuckle spindle 3 to which a wheel is attached is provided at the bottom of the cylinder 1. Also cylinder 1
A rebound stopper 4 and a dry bearing 5a are provided at the upper part of the cylinder 1, and a seal portion 6 for sealing between the cylinder 1 and a hollow rod 8 described below is further provided. For this seal portion 6, an oil seal or the like is used, for example.

A hollow rod 8 is slidably inserted into the cylinder 1. Inside this hollow rod 8,
An oil chamber 9 and a main gas chamber 10 are provided. 5b is a dry bearing. A damping force generating mechanism 12 is provided at the lower part of the hollow rod 8 between the oil chambers 2 and 9. This damping force generation mechanism 1
2 is an orifice 13 using a well-known plate valve.
and a variable orifice member 1 that can change the orifice flow rate by changing the rotational position.
4, and this variable orifice member 14 is adapted to be rotated by a switching drive source 16 via a drive rod 15. As this switching drive source 16, a motor, a rotary solenoid, or the like is used. 17 is a lead wire.

Further, a shaft 20 that rotates together with the drive rod 15 protrudes from the upper surface side of the switching drive source 16, and the valve body 21a of the switching valve 21 is rotationally driven by this shaft 20. . This switching valve 21 is
The gas passage 22 is opened and closed depending on the rotational position of the valve body 21a.

The gas passage 22 is formed in an end member 25 attached to the upper end surface of the hollow rod 8. Further, a bumper rubber 26 is provided on the lower surface side of the end member 25. Further, a mounting member 28 is rotatably provided on the upper surface side of the end member 25 via a thrust bearing 27. This attachment member 28 is fixed to the vehicle body side. 29 is a mount insulator made of an elastic member.

Further, a gas chamber outer cylinder 35 is provided concentrically on the outside of the hollow rod 8 so as to surround the outside of the seal portion 6. This gas chamber outer cylinder 35 is fixed to the end member 25. And gas chamber outer cylinder 35
An auxiliary gas chamber 36 is formed between the hollow rod 8 and the hollow rod 8. The auxiliary gas chamber 36 communicates with the main gas chamber 10 via the gas passage 22 and the switching valve 21. Further, gas leaking from the seal portion 6 is introduced into the auxiliary gas chamber 36. Both gas chambers 10 and 36 are each filled with high pressure nitrogen gas.

Further, the space between the gas chamber outer cylinder 35 and the cylinder 1 is sealed by a gas seal member 40 in the shape of a bellows frame. One end of this gas seal member 40 is fixed to the gas chamber outer cylinder 35 using a band 41, and the other end is fixed to the upper end of the cylinder 1 using, for example, a rebound stopper 4. Further, the outside of the gas seal member 40 is covered with a cylindrical cover 42, and the gas seal member 40 is configured to move vertically while being inverted inside the cover 42. The base of this cover 42 is fixed to the gas chamber outer cylinder 35 using a band 41.

In the suspension system having the above structure, the hollow rod 8 expands and contracts with respect to the cylinder 1, thereby exerting a spring function due to the repulsive force of the gas, and a damping function due to the damping force generating mechanism 12 flowing through oil. Then, the switching valve 21 is opened to allow the gas chambers 10 and 36 to communicate with each other, and at the same time, the variable orifice member 14 is opened.
If you open it fully, you can lower the spring constant and damping force, improving ride comfort.

Also, conversely, the switching valve 21 is closed and the gas chambers 10 and 3 are closed.
6 and close the variable orifice member 14, both the spring constant and the damping force become large, and the steering stability can be improved. Therefore, it is effective when the vehicle turns, suddenly accelerates, or stops suddenly.
Then, these driving conditions may be automatically detected by a sensor or the like and the switching drive source 16 may be operated.
Alternatively, the switching drive source 16 may be operated by a manual signal. Further, either the spring constant or the damping force may be changed.

According to the above-mentioned suspension system, even if gas dissolved in the oil escapes from the seal portion 6, this gas is collected in the auxiliary gas chamber 36 and does not leak to the outside. Moreover, since the gas pressure of the auxiliary gas chamber 36 is applied to the seal portion 6 from the outside thereof, the differential pressure of the seal portion 6 is small. As a result, the sliding resistance of the seal portion 6 is reduced, and the seal member only needs to have a low pressure resistance.

Furthermore, since an inert gas such as nitrogen gas is used as the filler gas, there is no risk of ignition even when highly compressed. Therefore, the volume of the main gas chamber 10 can be made sufficiently smaller than the volume of the auxiliary gas chamber 36, and the rate of change of the spring constant can be increased.

Furthermore, since the gas seal member 40 is housed inside the cover 42, the gas seal member 40 can be protected from dirt, dust, etc., and since the cover 42 presses the gas seal member 40, the bellow frame used for the gas seal member 40 is A material with relatively low withstand voltage and low deformation resistance may be used.

Note that FIG. 2 shows a second embodiment of the present invention. In this case, a compression coil spring 52 is provided between a spring seat 50 provided on the cylinder side and a spring seat 51 provided on the rod side. 53 is an insulator made of an elastic material. According to the structure of the second embodiment, since the pressure of the sealed gas can be lowered by the load borne by the coil spring 52, the pressure resistance of the gas seal member 40 can be lowered, and the deformation resistance can also be lowered. Therefore, the movement of the rod 8 becomes even smoother. and coil spring 52
It is preferable to use a non-linear characteristic spring whose spring constant increases with increasing deflection. In this case, the load borne by the coil spring 52 changes so as to offset the change in the gas chamber volume caused by the temperature change, so that changes in vehicle height due to temperature can be reduced. Since the other configurations and effects are the same as those of the first embodiment, corresponding parts are given the same reference numerals and explanations will be omitted.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain a suspension device that is free from gas leakage and has a small differential pressure at the seal portion. In addition, the gas spring constant can be changed as necessary, and the gas passage that communicates the main gas chamber and the sub-gas chamber with each other can be short and simple. It is also relatively easy to install a driving source.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a suspension device showing a first embodiment of the present invention, and FIG. 2 is a sectional view showing a second embodiment of the invention. DESCRIPTION OF SYMBOLS 1... Cylinder, 2... Oil chamber, 6... Seal part, 8... Hollow rod, 9... Oil chamber, 10... Main gas chamber, 22... Gas passage, 35... Gas chamber outer cylinder, 36 ...Auxiliary gas chamber, 40...Gas seal member.

Claims (1)

[Claims] 1 A hollow rod 8 having a cylinder 1 having an oil chamber 2 inside, a main gas chamber 10 slidably inserted into the cylinder 1 and having an oil chamber 9 inside and a main gas chamber 10 filled with compressed gas above the oil chamber 9. , a seal portion 6 for sealing between the cylinder 1 and the hollow rod 8, a gas chamber outer cylinder 35 provided outside the hollow rod 8 and concentrically with the hollow rod 8, and the gas chamber outer cylinder 3.
an auxiliary gas chamber 36 provided between the inner surface of the hollow rod 5 and the outer surface of the hollow rod 8 and filled with the compressed gas;
A gas passage 22 that communicates the main gas chamber 10 and the auxiliary gas chamber 36, a switching valve 21 and a switching drive source 16 that can switch communication and cutoff of the gas passage 22, and one end connected to the cylinder 1. A suspension system for a vehicle, comprising: a gas seal member 40 in the form of a bellows frame, which is fixed to the gas chamber outer tube 35 with the other end reversed and fixed to the gas chamber outer tube 35 to seal the auxiliary gas chamber 36.