JPS6067209A - Suspension device for vehicle - Google Patents

Abstract

PURPOSE:To restrict generation of damping force in response to small vibrations for better travelling comfort by providing in a hollow rod a valve body having an orifice serving to complete communication between an oil chamber in a cylinder and an oil chamber in the hollow rod. CONSTITUTION:A hydraulic pneumatic actuator 1 includes a cylinder 3 having at the lowermost end thereof a fixture 4 for attaching the actuator 1 to a part on the axle side and inside thereof an oil chamber 5. The cylinder 3 accomodates a hollow rod 8, and the inside of the hollow rod 8 is transversely divided by a free piston 11 into an upper gas chamber 12 and a lower oil chamber 13. The oil chamber 13 communicates with the oil chamber 5 through an orifice 15 of a valve body 16 provided in piston means 14. Thus constructed, compression of the rod 8 causes only movement of the valve body 16 and no flow of oil through the orifice, no damping force produced to prevent transmission of shocks at riding on small projections on the road surface for improved travelling comfort.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle suspension system using a hydropneumatic actuator.

This type of suspension system has 7 cylinders containing oil inside,
It is completely equipped with a rod that is extendably inserted into this cylinder and has an oil chamber and a gas chamber inside, and this gas chamber is filled with high pressure gas such as nitrogen gas and is provided with an orifice connected to the oil chamber. The high-pressure gas elastically supports the load from the vehicle body, and when the rod expands and contracts, oil flows through the orifice, thereby exerting a damping force.

However, in conventional devices of this type, the lubricating body with the orifice is fixed to the rod, so even small vibrations pass through the hydraulic orifice and exert a damping force. Therefore,
There was a problem with the impact being too strong. This invention has been developed based on the above-mentioned circumstances, and its purpose is to provide a damping force against small vibrations. An object of the present invention is to provide a suspension system for a vehicle that can provide a good ride quality by suppressing the occurrence of .

In other words, the gist of the present invention is to provide a cylinder having an oil chamber inside, a hollow rod telescopically inserted into the cylinder and having an oil chamber and a gas chamber inside, and a cylinder provided in the hollow rod. A valve body is provided with an orifice that communicates the oil chamber with the oil chamber of the hollow rod. This is a suspension system for a vehicle characterized by being provided with an elastic member that biases the vehicle toward the room.

According to the above configuration, when the rod contracts with respect to the cylinder, the pressure in the oil chamber of the cylinder increases, so that the valve moves relatively toward the rod oil chamber side against the repulsive force of the elastic member. Moving. Therefore, when the amount of movement in the rod compression direction is small, substantially only the valve body moves, and since almost no oil passes through the oriice, the generation of damping force is negligible. If the amount of movement in the rod compression direction is large, the pulp body will not move any further, and therefore oil will flow through the orifice, allowing normal damping force to be exerted.

On the other hand, when the rod extends, the valve body does not move, or the valve body moves little because it hits an interposed elastically deformable stopper (not necessarily required) in the direction of movement, or the valve body moves only slightly. Because there is no damping force, the damping force can be exerted with good response when the rod extends.

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 indicates a hydropneumatic actuator as a vehicle suspension system.

This actuator 1 is constructed as described below. That is, 3 is a cylinder, and a mounting portion 4 for mounting to a member on the axle side is provided on the lower end side of the cylinder 3 in the drawing. Further, an oil chamber 5 is provided inside the cylinder 3 and contains oil. Also cylinder 3
An oil seal 6 and a rebound stopper rubber 7 are attached to the upper end side in the figure.

A hollow rod 8 is extendably inserted into the cylinder 3. The outside of this rod 8 is covered with a protective cover 9. 10 is bread and rubber. The interior of the hollow rod 8 is partitioned into upper and lower parts by a free piston 11, with a gas chamber 12 containing high pressure gas such as nitrogen formed on the upper side, and an oil chamber 13 formed on the lower side. The oil chamber 13 communicates with the oil chamber 5 of the cylinder via an orifice 15 of a valve body 16 provided in the piston portion 14.

As shown in FIGS. 2 and 3, the orifice 15 is a valve 7 made of synthetic resin or sintered metal. A first orifice 17 formed in the main body 16a, a second orifice 18 that is smaller than the first orifice 17, and a switching orifice 19 for adjusting the damping force that can be switched open and closed. It is composed of...

This switching orifice 19... is opened and closed by rotating the shaft 21 of the pulse body according to its rotational position. be. The operating shaft 21 vertically passes through the hollow opening, the inside of the door 8, and the free piston 11, and is rotated by a rotary solenoid 22.

Further, the operating shaft 21 is inserted through a groove 23 for maintaining liquid tightness.

Further, the cylindrical body J6b to which the valve body main body 16a is attached is provided at the tip end 21m of the operating shaft so as to be movable in the axial direction (vertical direction in the figure) by a small distance m (see Fig. 4). It is being Therefore, the valve body 16a
It is also possible to move up and down over a distance of m.

Valve plates 20a and 20b are attached to the upper and lower surfaces of the valve body main body 26a, respectively, and the upper valve plate), ? Oa closes the outlet of the first orifice 17, and the lower valve plate 20b closes the outlet of the second orifice 18, like a check valve.

Further, a compression coil spring is provided as an example of the elastic member 24 that urges the valve g7j-16 toward the oil chamber 5 of the cylinder.

Further, a stopper 25 made of an elastic resin material is provided on the lower surface side of the pulp body main body 16h as shown in the drawing.

Further, 26 and 27 in the figure indicate seal washers.

The seal washers 26, 27f-J closely contact the lower surface of the free piston 11 to seal gas when the free piston 11 descends to the lower limit position and the gas chamber 12 reaches its maximum volume.

In the device of this embodiment having the above configuration, when the rod 8 is in a stationary state with respect to the cylinder 3, when the rod 8 moves in the extending direction (upward in the figure) during pulse etc., the valve is opened as shown in FIG. The main body 16a immediately hits the stop groove 25, and the oil passing through the second orifice 18 pushes open the valve grate 20b and flows into the lower oil chamber 5. Therefore, when the rod is extended, the damping force can be exerted with good responsiveness even to minute vibrations. Note that if the switching orifice 19 is open at this time, oil also flows through this orifice 19.

On the other hand, when the rod 8 is compressed, the pressure in the oil chamber 5 of the cylinder increases, so as shown in FIG. 4, the pulp body 16 first compresses the elastic portion 4424 and moves relatively by a distance m.

Therefore, if there is only a minute vibration within this movement range m, there is no damping force, so substantially no damping force is generated. Therefore, even when the vehicle runs over, for example, a minute protrusion on the road surface, the impact is not transmitted, resulting in improved riding comfort. Further, when the amount of compression of the rod 8 is large, oil flows through the orifice 17.19f, and a normal damping force can be exerted.

As described above, the present embodiment has the characteristics that it does not respond to minute inputs in the rod compression direction, and that the damping force has good responsiveness to small amplitudes in the rod extension direction.

In addition, since synthetic resin is used as the material for the pulp body 16a and the nut pad 25 is made of an elastic resin material, so-called tapping noise is extremely small and noise can be reduced. In addition, high pressure gas is sealed in the gas chamber 12 of the rod, and positive pressure is always applied to the oil, so the pulp body 16, valve plate 20ta,
Even if 20b moves at high speed within the above m range, the oil does not become under negative pressure, and the occurrence of aeration can be reliably prevented.

In carrying out the present invention, it goes without saying that the specific aspects of the cylinder, rod, pulp body, orifice, elastic member, etc. can be modified in various ways without departing from the gist of the present invention. As described above, according to the present invention, it is possible to suppress the generation of damping force during small vibrations, and there is an effect in improving the ride comfort of the vehicle.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a longitudinal cross-sectional view of the suspension system, FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. 1, and FIG. FIG. 4 is a vertical sectional view taken along line 1--1 in different operating states. 3... Cylinder, 5... Oil chamber, 8... Hollow port, 12... Gas chamber, 13... Oil chamber, 14... Piston part, 15... Orifice, 16 ...Valve d?
17...first orifice, 18...second orifice, 24...elastic member.

Claims (1)

[Claims] A cylinder that has an oil chamber inside, a hollow rod that is telescopically inserted into this cylinder and has an oil chamber and a gas chamber inside, and a cylinder that is installed in this hollow rod to communicate the oil chamber of the cylinder and the oil chamber of the hollow rod. and a valve body having an orifice that allows the valve body to move by a small distance in the axial direction of the hollow rod.
'7'yl? 7''- toward the oil chamber side of the cylinder.