JPH03219132A - Hydraulic pressure buffer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a hydraulic shock absorber in which the magnitude of the damping force generated within a linter can be freely changed.

BACKGROUND ART This type of hydraulic shock absorber generally has a control rod attached to the axial center of the piston rod, and the damping force can be switched in multiple stages, for example, in two stages, large and small, by operating this control rod. .

Conventional hydraulic shock absorbers of this type have communication holes provided at the periphery of the piston, which is the valve body, and near the axes of the piston and piston rod, to communicate between the liquid chambers. The first damping valve and the second damping valve are respectively faced, and the communication hole in the vicinity of the axis is opened and closed from the inside of the piston rod by operating the control rod, thereby switching between operation and non-operation of the second damping valve, This provides a structure in which the damping force generated within the shock absorber body is switched. (For example, see Japanese Patent Application Laid-Open No. 189338/1983.) Problems to be Solved by the Invention However, in the case of the above-mentioned hydraulic shock absorber, the communication hole itself in the vicinity of the axis is opened and closed by a control rod. Therefore, the communication hole in the vicinity of the axis cannot be made into a simple shape that penetrates vertically in a straight line. The shape had to be bent to Il. For this reason, there is a problem in that the machining for forming the communication hole in the vicinity of the axis becomes rough and difficult, resulting in high costs. Additionally, because a complicated communication hole must be provided in a limited space near the axis of the piston and piston rod, the magnitude and characteristics of the damping force that can be switched are limited to an extremely narrow range. This has become a problem.

Therefore, the present invention makes it possible to switch the damping force with an extremely simple structure, and can be manufactured at low cost.
Moreover, the present invention aims to provide a hydraulic shock absorber with a high degree of freedom in switching the damping force.

Means for Solving the Problems The present invention provides, as a means for solving the above-mentioned problems, a communication system formed in a valve body provided to partition liquid chambers in a shock absorber body so as to communicate between the liquid chambers. a hole, an annular groove formed on the end surface of the valve body including the communicating hole, an inner seat surface formed on the outer periphery of the annular groove, and an inner seat surface located on the outer periphery side of the inner seat surface. an outer seat surface formed to protrude from the inner seat surface, a first damping valve seated on the inner seat surface, a second damping valve seated on the outer seat surface, and at least one of the first damping valve and the second damping valve. A switching means for separating either one from the corresponding sheet surface.

By operating the action switching means, the first damping valve and the second damping valve are appropriately seated on the inner seat surface and the outer seat surface, or
By separating them, the passage resistance acting on the hydraulic fluid that has passed through the communication hole and the annular groove can be switched in multiple stages, and accordingly, the damping force within the shock absorber body can also be switched.

EXAMPLE Hereinafter, an example of the present invention will be described based on FIGS. 1 to 4.

In Figures 1 to 4, 1 is a cylinder of the shock absorber body filled with hydraulic fluid, and 2 is a cylinder that is slidably installed inside the cylinder 1 and whose interior is divided into an upper liquid chamber 3 and a lower liquid chamber 4. The piston serves as the dividing valve body. Also, 5 is
It is a piston rod whose lower end is coupled to the piston 2 and whose upper end projects outside the cylinder 1.

The piston 2 is provided with communication holes 6 and 7 that linearly communicate the upper liquid chamber 3 and the lower liquid chamber 4, and the communication hole 7 is arranged on the outer circumferential side of the communication hole 6.

The communication hole 7 becomes a passage for hydraulic fluid that moves from the lower liquid chamber 4 to the upper liquid chamber 3 when the piston 2 is retracted, and the communication hole 6 moves from the upper liquid chamber 3 to the lower liquid chamber 4 when the piston 2 is extended. It becomes a passage for the hydraulic fluid.

A seat surface 9 is formed on the upper end surface of the piston 2, with which a disc valve 8, which is a damping valve, comes into contact. on the other hand,
On the lower end surface of the piston 2, an annular groove 6a is formed to include the communication hole 6, and an inner seat surface 10 is formed on the outer peripheral side of the annular groove 6a. On the outer peripheral side, an outer seat surface 11 is formed so as to protrude toward the lower liquid chamber 4 side than the inner seat surface IO. A disc valve 12 as a first damping valve is seated on the inner seat surface 10, and a disc valve 13 as a second damping valve is seated on the outer seat surface 11. A through hole 8a is formed on the inner diameter side of the disc valve 8 to allow constant communication between the upper liquid chamber 3 and the communication hole 6, and a constant orifice (not shown) is formed on the inner seat surface 11. It is engraved.

A shaft hole 14 is formed in the piston rod 5, and a control rod I5 serving as a switching means for switching and adjusting the damping force is inserted into the shaft hole 14 so as to be slidable in the axial direction. In addition, 16 in the figure is a seal ring that maintains the seal between the shaft hole 14 and the control rod 15. Also,
piston mouth.

The lower edge of the door 5 is formed to have a small diameter with the stepped portion 17 as a boundary, and this small diameter portion is inserted into the center of the piston 2 in a penetrating state. The piston rod 5 passes through the piston 2 and is tightened with a nut 18. At this time, disc valves 8 and 12 are fitted into the lower edge of the piston rod 5, and the disc valve 8 is attached to the piston 2. The disc valve 12 is clamped by the upper surface and the step I7 of the piston rod 5, and by the lower surface of the piston 2 and the nut 18, respectively. Thereby, the disc valve 8 is seated on the seat surface 9, and the disc valve 12 is seated on the inner seat surface 10.

A disc valve 13 is fastened to the lower end of the control rod 15 which protrudes through the lower part of the piston rod 5 by means of a screw 19, and a control rod 15 which protrudes through the upper part of the piston rod 5 is tightened and fixed. A nut 20 for switching the damping force is fixed to the upper end 4. When the control rod 15 is in the lowered position, the disc valve 13 is separated from the outer seat surface 11 and becomes inoperable (inoperative state), and only when the control rod 15 is raised, the disc valve 13 is moved away from the outer seat surface 11. It is seated and ready for operation. Nara) 20 is screwed onto the upper end of the piston rod 5, and moves up and down together with the control rod 15 by rotating the piston rod 5 in the left and right directions, thereby seating the disc valve 13 against the outer seat surface 11. Or make them leave.

In the above configuration, the disc valve 1 is
3 is separated from the outer seat surface 11.
As it slowly moves in the direction of extension, the working fluid in the upper fluid chamber 3 passes through the through hole 8a and the communication hole 6, and then passes through the constant orifice cut into the inner sheet surface 10, where it generates a damping force and further It flows into the lower liquid chamber 4. In addition, when the piston 2 rapidly moves in the extension direction in the same state, the hydraulic fluid that has passed through the through hole 8a and the communication hole 6 from the upper liquid chamber 3 pushes open the disc valve 12, which generates a damping force and further It flows into the lower liquid chamber 4.

The relationship between the speed of the piston 2 and the damping force within the cylinder 1 when the disc valve 13 is separated from the outer seat surface 11 is as shown in FIG.

Further, when the disk valve 13 is seated on the outer seat surface 11 by rotating the NAND 20 from this state, the hydraulic shock absorber 2g according to the present invention operates as follows.

When the piston 2 moves slowly in the extension direction, the working fluid in the upper fluid chamber 3 passes through the through hole 8a and the communication hole 6, passes through the constant orifice, pushes open the disc valve 13, and flows into the lower fluid chamber 4. At this time, damping force is generated by the constant orifice and the disc valve 13.

Furthermore, when the piston 2 moves rapidly in the extension direction, the hydraulic fluid that has passed through the through hole 8a and the communication hole 6 from the upper fluid chamber 3 pushes open the disc valve 12, and then pushes open the disc valve 13, causing the lower fluid chamber to open. 4. At this time, damping force is generated by the disc valves 12 and 13.

FIG. 3 shows the relationship between the moving speed of the piston 2 and the damping force generated in the disc valve 13, and FIG. The relationship between damping force is shown.

In this hydraulic shock absorber, two types of damping characteristics, the damping characteristic shown in FIG. 2 and the damping characteristic shown in FIG.

In addition, in the case of this hydraulic shock absorber, when the piston 2 is retracted, the disc valve 8 or the communication hole 7 Open the lower liquid chamber 4.
The working fluid is allowed to pass from the upper fluid chamber 3 to the upper fluid chamber 3. Incidentally, in the above embodiments, a constant orifice is provided in the inner sheet 10, or a mode in which no constant orifice is provided can of course be adopted.

Further, in the above embodiment, the disc valve 13 is seated on or separated from the outer seat surface 1 by operating the switching means (control valve 15). The disc valve 12 may be seated at all times, and the disc valve 12 side may be seated on or separated from the inner seat surface 10 by a switching means. The outer seat 11 may be seated on or separated from the outer seat 11, respectively.

Furthermore, the separation distances of the disc valves 12 and 13 from the inner seat 10 and the outer seat surface 11 may not be uniform, but may be changed as appropriate.

Further, in the above embodiments, the piston 2 is used as an example of the valve body, but the piston 2 is not limited to the piston 2, and may be a base valve.

Effects of the Invention As described above, the present invention switches the damping force by switching between seating and separation of the first damping valve and the second damping valve with respect to the inner seat surface and the outer seat surface by operating the switching means. Unlike the conventional valve body in which a portion of a plurality of communication holes provided in the valve body are opened and closed, the communication hole that communicates between the liquid chambers can be formed into a simple linear shape. As a result, there are fewer restrictions on forming the communication hole, which simplifies the structure of the valve body, making it possible to manufacture it at low cost, and increasing the degree of freedom in switching the damping force.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a graph showing the damping characteristics of the first damping force generating valve in the same embodiment, and FIG. 3 is a graph showing the second damping force in the same embodiment. FIG. 4 is a graph showing the damping characteristics of the first damping force generating valve and the second damping force generating valve in the same embodiment. 2... Piston (valve body), 3... Upper liquid chamber, 4. Lower liquid chamber, 6... Communication hole, 6a... Annular groove, 1
0...Inner seat surface, 11...Outer seat surface, 12
... Disc valve (first damping valve), 13... Disc valve (second M damping valve), I5... Control rod (switching means).

Claims (1)

[Claims] (1) A communication hole formed in a valve body provided to partition a liquid chamber in a shock absorber body to communicate between the liquid chambers, and a communication hole formed in an end face of the valve body. an annular groove, an inner seat surface formed on the outer periphery of the annular groove, an outer seat surface formed on the outer peripheral side of the inner seat surface and protruding from the inner seat surface, and a seat seated on the inner seat surface. a first damping valve, a second damping valve seated on the outer seat surface, and a switching means for separating at least one of the first damping valve and the second damping valve from the corresponding seat surface. A hydraulic shock absorber characterized by: