JPH0313363Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an automobile suspension, and particularly to one in which the spring constant of a bush attached to a suspension arm can be variably controlled.

(Prior Art) Conventionally, in an automobile suspension, in order to prevent vibrations from being transmitted to the vehicle body, it is customary to connect the suspension arm to the vehicle body via a rubber bush.

Incidentally, in order to improve passenger comfort and steering response, there is a demand for changing the spring constant of a bushing that connects a suspension arm to a vehicle body depending on driving conditions.

(Problems to be Solved by the Invention) However, in the conventional rubber bushing as described above, since the spring constant is constant, there is a problem that the above-mentioned requirements cannot be satisfactorily met.

Incidentally, as shown in Japanese Utility Model Application Publication No. 57-205432, for example, in a flexible bushing that is inserted into a connecting end of a tension rod or the like that supports the force acting on the wheel in the longitudinal direction of the vehicle, the flexible bushing is It is proposed that a fluid chamber is provided in the brake system, and a brake fluid path from a hydraulic pressure generating part of the brake device to the wheel cylinder is connected to the fluid chamber, thereby increasing the rigidity of the flexible bushing during braking. However, this proposed technique cannot satisfy the above-mentioned requirement of controlling the spring constant of the bush according to the operating conditions as described above.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automobile suspension in which the spring constant of a bush attached to a suspension arm can be variably controlled depending on driving conditions (for example, driving conditions).

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an inner cylinder, an outer cylinder, and a rubber interposed between the two cylinders, which are provided at the connection part between the suspension arm and the vehicle body. A bush having an elastic body, a liquid chamber formed in the rubber elastic body of the bush, an intermediate cylinder interposed between the inner cylinder and the outer cylinder with the liquid chamber sandwiched between them, and disposed at both ends of the bush. A contact member provided on the inner cylinder or the outer cylinder with a gap between the intermediate cylinder and the liquid chamber is interposed between the liquid chamber and the pressure source, and changes the volume of the liquid chamber according to the operating state. and pressure control means for variably controlling the spring constant of the bush by changing the positional relationship between the end of the intermediate cylinder and the abutting member.

(Function) During a specific operation, the pressure in the liquid chamber is increased by the control means, and the volume of the liquid chamber is expanded. Due to the expansion, the rubber elastic body is deformed, and accordingly, the end of the intermediate cylinder is displaced toward the abutting member and is pressed against the abutting member. As a result, the intermediate cylinder has a cantilever-like shape, and the resistance force against the movement of the rubber elastic body in the axial direction and the direction perpendicular thereto is increased, so that the bush has increased rigidity and a large spring constant.

On the other hand, during other operations, the pressure in the liquid chamber is not increased by the control means, so the liquid chamber does not expand. Therefore, the end of the intermediate cylinder is not pressed against the abutting member, and the rubber elastic body as a whole has an elastic function, so that the bush has a low rigidity and a low spring constant.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

In FIG. 1, which shows the relationship between the suspension arm and the control system attached to it, 1 is a suspension arm, and a bushing 2 is attached to the end of the suspension arm that serves as a connection between the suspension arm 1 and the vehicle body (not shown). ，
2 is installed.

As shown in detail in FIGS. 2 and 3, the bush 2 includes a cylindrical inner tube 3, a flange portion 4a that is shorter than the inner tube 3, and has an end edge bent inward.
4a, and a rubber elastic body 5 interposed between the two cylinders 3 and 4.

Inside the rubber elastic body 5 is an annular oil chamber (liquid chamber).
6 is formed, two intermediate cylinders 7, 7 are buried coaxially with the oil chamber 6 in between the inner cylinder 3 and the outer cylinder 4, and two auxiliary cylinders are further installed near the outer cylinder 4. The tubes 8, 8 are buried coaxially. Auxiliary cylinder 8, 8
One end portion of the rubber elastic body 5 comes into contact with the flange portions 4a, 4a of the outer cylinder 4 to prevent extreme deformation of the rubber elastic body 5 when the oil chamber 6 expands.

At both ends of the inner cylinder 3, there are annular plates 9 as abutting members, with a gap S between them and the end of the intermediate cylinder 7.
9 is fixedly installed, and rubber elastic bodies 10, 10 are installed at portions of the plates 9, 9 facing the ends of the intermediate cylinder 7.

Reference numeral 11 denotes an opening portion fixed to the outer cylinder 4, and the opening 11a communicates with the oil chamber 6 through the through hole 4b of the outer cylinder 4. This opening 11 is located at the injection position 12a.
and a discharge position 12b.
2, it is connected to an oil pump 13 (pressure source) and an oil tank 14. Solenoid valve 12
is interposed between the oil chamber 6 and the oil pump 13, and changes the volume of the oil chamber 6 according to the operating condition to change the positional relationship between the end of the intermediate cylinder 7 and the plates 9, 9. It functions as a pressure control means for variably controlling the spring constant of the bush 2.

15 is an accumulator, and 16 is an orifice.

With the above configuration, in a specific operating state, the solenoid valve 12 is energized and becomes the injection position 12a, so oil is supplied to the oil chamber 6 of each bush 2 by the operation of the oil pump 13, and the oil chamber 6 expands in the axial direction X (see Figure 4). Due to the expansion, the rubber elastic body 5 is displaced in the axial direction
The ends of the intermediate cylinders 7, 7 are pressed against the rubber elastic bodies 10, 10 of the plates 9, 9.

As a result, the intermediate cylinders 7, 7 have a cantilever-like shape, and the resistance to movement in the axial direction Spring constant increases.

On the other hand, in other operating states, the solenoid valve 12 is in the demagnetized state and is at the discharge position 12b.
The oil chamber 6 of the bush 2 does not expand. Therefore,
The ends of the intermediate cylinders 7, 7 are not pressed against the rubber elastic bodies 10, 10 of the plates 9, 9, and the elastic body 5 as a whole has an elastic function, so that the bush 2 has a small rigidity and a small spring constant.

By controlling the switching of the solenoid valve 12 in this manner, the spring constant of the bush 2 can be easily variably controlled.

Note that the above-mentioned specific driving conditions include, for example, a vehicle speed range where shimmy occurs where the wheels violently vibrate;
Possible cases include when steering. By increasing the spring constant and increasing the rigidity of the bush 2, in the former case, the resonance point can be shifted to reduce vibrations, and in the latter case, the bundle can be cut easily.

(Effects of the Invention) Since the present invention is constructed as described above, the spring constant of the bushing attached to the suspension arm can be easily variably controlled in accordance with the running condition, even with a simple structure.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; Fig. 1 is an overall configuration diagram showing the relationship between the bushing attached to the suspension arm and the control system; Fig. 2 is a vertical sectional view of the bushing; A cross-sectional view along the - line of
FIG. 4 is a diagram similar to FIG. 2, showing a state in which oil pressure is applied to the oil chamber. DESCRIPTION OF SYMBOLS 1... Suspension arm, 2... Bush, 3... Inner cylinder, 4... Outer cylinder, 5... Rubber elastic body, 6... Oil chamber (liquid chamber), 7... Intermediate cylinder, 9...
... Plate (contact member), 12 ... Solenoid valve (pressure control means), 13 ... Oil pump (pressure source).

Claims (1)

[Scope of Claim for Utility Model Registration] A bushing provided at a connecting portion between a suspension arm and a vehicle body and having an inner cylinder, an outer cylinder, and a rubber elastic body interposed between the two cylinders, and a rubber elastic body of the bushing. an intermediate cylinder interposed between the inner cylinder and the outer cylinder with the liquid chamber in between; an inner cylinder or An abutting member provided on the outer cylinder is interposed between the liquid chamber and the pressure source, and the volume of the liquid chamber is changed depending on the operating state, so that the end of the intermediate cylinder and the abutting member are connected to each other. and pressure control means for variably controlling the spring constant of the bush by changing the positional relationship.