JPS58184336A - Fluid-pressure shock absorber - Google Patents

Abstract

PURPOSE:To obtain a proper damping capacity in accordance with the loaded weight by selectively opening and closing an orifice connecting the upper chamber of a cylinder through to a reservoir chamber via a sleeve in accordance with the loaded weight. CONSTITUTION:On the upper part of a cylinder 1, a sleeve-fitting part 22 is provided with an orifice 23 connecting between a cylinder upper chamber 6 and a reservoir chamber 9. In the sleeve-fitting part 22, a dashpot is formed with little capacity change at the high-speed movement of a piston 5 agaist the inner circumferential face, and a sleeve 25 connected by the piston 5 and a spring 26 to open and close the orifice 23 selectively is fitted to be freely slided in a loaded or a vacant car. In the reservoir chamber 9, a liquid-guide cyliner 28 is provided with its upper end side connected to the orifice 23 and its lower end side to the operation liquid in the reservoir chamber 9.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic shock absorber, and more particularly to a hydraulic shock absorber whose damping force changes in response to changes in load weight.

A conventional hydraulic pressure relief device was constructed as shown in FIG.

That is, in the cylinder 1 filled with the working liquid, there are communication holes 2 on the upper and lower surfaces that allow limited circulation of the working liquid, and the communication holes 2.
A piston 5 equipped with a damping force generating means 4 consisting of a valve plate 3 that always closes the cylinder I is slidably inserted into the cylinder 1 to form an upper and lower double space 6.7, and furthermore, the cylinder I and A reservoir chamber 9 for working fluid formed between the outer cylinder 8 surrounding the cylinder 1 is connected to a damping chamber 9 at the bottom thereof, which is composed of a communication hole 10 on the upper and lower surfaces and a valve plate 11 that always closes the communication hole 10. A pressurized gas 14 that pressurizes the liquid in the reservoir chambers 9 and 7 cylinders 1 is preferably sealed in the outer cylinder 8 and communicated through a bottom body 13 provided with a force generating means 12. A piston rod 15 fixed to the piston 5 protrudes from the top of the I. Note that 16 and 17 are check plates that always close the communication holes 18 and 19, respectively, and 20 and 21 are springs with a weak spring force that bias the respective check plates 16 and 17.

As is well known, such a hydraulic shock absorber is mounted on a vehicle by fixing the end of the piston rod 15 on the spring of the vehicle body and the cylinder I below the spring, and the extension of the piston rod 15 is fixed. During the stroke, the upper chamber 6 becomes under high pressure, and the working liquid in the upper chamber 6 pushes open the valve plate 3 through the communication hole 2, reducing the flow resistance by 9 points, the locking mechanism, and the like.
One, one, the liquid in the reservoir chamber 9 is in the bottom body 1.
The check plate 17 is easily pushed open through the communication hole 19 of No. 3 and flows into the cylinder 1 to compensate for the withdrawal volume of the piston rod 15. On the other hand, during the compression stroke of the piston rod 15, the liquid in the lower chamber 7 pushes up the check plate 16 from the communication hole 18 of the piston 5 and easily flows into the upper chamber 6. The liquid flows from the communication hole 10 of the bottom body 13 to the valve plate 1.
] is pushed open and flows into the reservoir chamber 9 while creating a flow resistance, that is, a damping force, and further compresses the pressurized gas 14 within the reservoir chamber 9. In this way, a desired damping force is generated in the extension stroke according to the operating speed of the piston rod 15.

Therefore, in such a conventional hydraulic shock absorber, the damping force at the same operating speed of the piston rod 15 is constant regardless of changes in the loaded weight of the vehicle, and the damping force is normally set according to the normal loading. Since the damping force is selected based on the load, the damping force is not necessarily the most preferable depending on the sprung load when the vehicle is empty or when the vehicle is fully loaded, and therefore the ride comfort or steering stability is not fully satisfactory.

The present invention was developed in view of the above-mentioned conventional situation, and is a hydraulic damping system that can contribute to improving ride comfort or handling stability of a vehicle by changing the damping force in accordance with variations in the amount of loaded vehicles, that is, the sprung mass load. The purpose is to obtain sanitary equipment.

Embodiments of the present invention will be described in detail below with reference to the drawings. Note that the same reference numerals are given to the same constituent parts as in the conventional art, and redundant explanation thereof will be omitted.

FIGS. 2 and 3 are cross-sectional views showing one embodiment of the present invention,
In the figure, 〃 is a sleeve fitting part that is provided in the upper part of the cylinder 1 and has an orifice 23 that communicates between the upper chamber 6 and the reservoir chamber 9. It is formed by fitting the shaped part into the cough cylinder I with the position of the orifice 23 and the position of the mounting port 1a of the liquid guide cylinder provided at 7/I1, which will be described later, aligned. . Further, the sleeve 25 is slidably fitted inside the sleeve fitting portion n with a desired clearance between the inner peripheral surface thereof and the sleeve 25 to form a dashbot N whose volume changes little when the piston 5 moves at high speed. It is inserted. The sleeve 25 is connected to the piston 5 while receiving a spring force in the direction of separating from the piston 5 by a position detection spring that is visible between the sleeve 25 and the piston 5. The piston is biased toward the piston by a spring I. When the sleeve 25 is loaded, a suspension spring (not shown) is bent by its spring load, and when the amount of penetration of the piston rod 15 increases, the sleeve 25 slides in a direction closer to the piston 5 by the spring force of the return spring I. The orifice 23 is closed. The stopper is a stopper that prevents the sleeve 25 from falling off. On the other hand, when the amount of penetration of the piston rod 15 when the vehicle is idle is reduced, the spring force of the position detection spring X causes the sleeve 25 to slide in the direction away from the piston, and the orifice 23 is unblocked. The elongation is a liquid guide cylinder whose upper end side is connected to the orifice 23 and whose lower end side is connected to the working liquid in the reservoir chamber 9, and the core part Z is formed in the shape of a pipe. The upper end of the cylinder 1 is attached by fitting it into the cylinder Ia, and the lower end thereof is submerged in the working fluid.

During loading, the orifice 23 is closed by the sleeve 5, and when the vehicle runs in this state, the piston rod 15 repeatedly slides up and down to absorb unsprung vibrations that occur due to uneven road surfaces. However, since this vertical movement is extremely fast, the dashbot 24 formed between the sleeve 25 and the inner peripheral surface of the sleeve fitting part
performs its function, and the sleeve 25 stays at the initial position. Therefore, the total amount of the working fluid displacing and flowing between the upper and lower chambers 6 and 7 and the reservoir chamber 9 is the same as that of the damping force generating means 4 of the piston 5 and the damping force generating means 1 of the bottom body 13.
2, a damping force is generated, and a large damping force can be obtained.

On the other hand, when the vehicle is empty, the blockage of the orifice 23 by the sleeve 5 is released, and when the piston rod 15 moves up and down at high speed in this state, the dashbot 24 exerts its function and the sleeve returns to the initial position, that is, the blockage of the orifice 23. is held in the position where it was released.

Therefore, a portion of the working fluid is transferred to the damping force generating means 4. Without passing through I2, the fluid bypasses the orifice 23 and the fluid guide sleeve and enters the respective chambers 6, 7.9, resulting in a small damping force.

In this way, the damping force is changed according to the increase or decrease in the loaded weight, and an appropriate damping force can be obtained according to the loaded weight.

Although FIGS. 2 and 3 show an example in which one orifice 23 is provided, it is within the scope of the present invention to provide a plurality of orifices 23 in a row in the axial direction. The damping force can be changed in multiple stages according to changes in weight,
It is possible to select an appropriate damping force depending on the loaded weight.

As explained above, the present invention includes a piston that is slidably inserted into a cylinder filled with a working liquid and equipped with a damping force generating means that allows limited flow of the working liquid. A reservoir chamber formed between the cylinder and an outer cylinder surrounding the seven cylinders is connected to a bottom body which is double-separated and has a damping force generating means at the bottom thereof, and the top of the cylinder In the hydraulic shock absorber, the piston rod fixed to the piston protrudes from the cylinder, and the upper part of the cylinder is provided with a sleeveless fitting part having an orifice that communicates with the upper chamber and the reservoir space. At the fitting part, a needle/yupot is formed between the inner circumferential surface of the fitting part and the volume changes little during high-speed movement of the piston, and
A sleeve connected to the piston with a spring is slidably fitted to selectively open and close the orifice when the vehicle is loaded or unloaded.
Since a liquid guide tube is provided whose upper end is connected to the orifice and whose lower end is connected to the working fluid in the reservoir chamber, a hydraulic shock absorber is obtained that can obtain an appropriate damping force depending on the load of the vehicle. This provides an excellent effect of improving the ride comfort and steering stability of the vehicle.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional hydraulic shock absorber, and Fig. 2 is a sectional view of a conventional hydraulic shock absorber. 1・
. FIG. 3 is a cross-sectional view when the vehicle is loaded, showing an embodiment of the present invention, FIG. 3 is a cross-sectional view when the vehicle is empty, and FIG. 4 is an enlarged view of the main part of FIG. 3. I... Cylinder, 4... Damping force generating means, 5 - Piston, 6 - Upper chamber, 7... Lower chamber, 8... Outer cylinder, 9
... Reservoir chamber, 12... Damping force generating means, 13.
...Bottom body, 15...Piston rod, n...
- Sleeve fitting part, 23... Orifice, 24...Datsunyu pot, 25...Sleeve, X...Spring, of course...Hydraulic pressure guide tube. Figure 4-22

Claims (3)

[Claims] (1) A piston equipped with a damping force generating means that allows limited flow of the working liquid is slidably inserted into a cylinder filled with working liquid, so that the inside of the 7 cylinders is divided into upper and lower layers,
The inside of the 71J cylinder is communicated with a reservoir chamber formed between the outer cylinder surrounding the cylinder through a bottom body having a reducing force generating means at the bottom thereof, and is fixed to the piston from the top of the cylinder. In a hydraulic shock absorber having a protruding piston rod, the upper part of the cylinder includes:
A sleeve fitting portion having an orifice that communicates between the upper chamber and the reservoir chamber is provided, and a dashpot is formed between the sleeve fitting portion and the inner circumferential surface of the sleeve fitting portion, the volume of which changes little during high-speed movement of the piston. At the same time, a sleeve connected to the piston and a spring is slidably fitted to selectively open and close the orifice when the vehicle is loaded or empty, and a sleeve is provided in the reservoir chamber, the upper end of which is connected to the orifice. A hydraulic shock absorber characterized in that a liquid guide cylinder is provided, the lower end of which is connected to the working liquid in the reservoir chamber. (2) One orifice is provided for each of the orifices;
A hydraulic shock absorber according to claim 1. (3) The hydraulic shock absorber according to claim 1, wherein a plurality of orifices are arranged in rows in the axial direction.