JPS6267344A - Oil hydraulic shock absorber - Google Patents

Abstract

PURPOSE:To enable workability to be substantially improved, by fitting a piston to be inserted into an inner cylinder in a condition that a pin is previously assembled to a piston rod. CONSTITUTION:To assemble a pin 12 into a hollow hole 10A, a shock absorber, previously stopping one end of a spring 13 to a stopper part 12D of the pin 12, inserts the pin 12 with the spring 13 into the hollow hole 10A to be deeply pressed into the hollow hole 10A. Accordingly, the shock absorber, enabling the other end of the spring 13 to be stopped to a stopper part 10B while the pin 12 to be easily assembled into the hollow hole 10A, can improve workability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hydraulic shock absorber, and particularly relates to a hydraulic shock absorber of a type that changes damping force in accordance with the stroke position of a piston.

[Prior art]

Generally, an annular oil chamber is disposed within the outer cylinder to form an annular oil chamber between the outer cylinder and the ffIf between the outer cylinder and the annular oil chamber and I! h
an inner cylinder provided with an oil passage therethrough, a piston slidably inserted into the inner cylinder and defining the inside of the inner cylinder into a piston upper chamber and a piston lower chamber; A piston rod is fixed to the piston and the other end projects outward from the inner cylinder and the outer cylinder, and the upper chamber and the lower chamber are connected through a hollow hole bored in the axial direction from the ends of the piston rod. A hydraulic shock absorber is known that includes a communicating path and pins of different sizes and diameters which are disposed within the hollow hole in order to make the effective cross-sectional area of the communicating path variable.

In this type of hydraulic shock absorber, one end of the pin is fixed to one end of the inner cylinder, and when the piston makes a large sliding displacement within the inner cylinder, the pin changes the effective cross-sectional area of the communication passage. The damping force generated can be changed. As a result, depending on the vibration conditions of the vehicle, it is possible to obtain a desired damping effect depending on the stroke position of the piston, such as generating a large damping force when the vehicle vibration is large and a small damping force when the vehicle vibration is small. can.

However, in the prior art, since one end of the pin is fixed to one end of the inner cylinder in advance, when the other end of the pin, which is now a free end, is loosely inserted into the hollow hole of the piston rod, In parallel with the operation of inserting the piston fixed to one end of the piston opening into the inner cylinder, the pin must be inserted into the hollow hole while visually checking the free end of the pin. If the pin is tilted even slightly within the inner cylinder, problems such as the free end of the pin hitting the lower surface of the piston or piston rod may occur, and the work of inserting the pin into the hollow hole becomes extremely troublesome. There is.

[Problem that the invention seeks to solve]

The present invention was made in view of the drawbacks of the prior art described above, and the problems that the present invention attempts to solve are as follows.

By making it possible to assemble the pin into the hollow hole of the piston rod in advance before inserting the piston into the inner cylinder, it is possible to improve workability, and also to adjust the damping force appropriately according to the stroke position of the piston during use. The object of the present invention is to provide a hydraulic shock absorber that can change the hydraulic shock absorber.

[Means for solving problems]

The feature of the structure adopted by the present invention in order to solve the above-mentioned problem tcIW is that the pin has no displacement in the axial direction of the piston rod.
This is because TfE is held by the piston rod.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2.

In the figure, reference numeral 1 denotes an outer cylinder formed into a cylindrical shape with a bottom. An annular groove IA is provided on the bottom side of the outer cylinder 1, and a rod guide 2 is fitted into the opening side of the outer cylinder 1. A lock ring 3 is screwed on from above. Reference numeral 4 denotes an inner cylinder disposed coaxially within the outer cylinder l, and the lower end side of the inner cylinder 4 is fitted into the groove IA through a cap 5 having a radial passage 5A on the lower surface side. , the upper end side is fitted into the rod guide 2 and positioned in the axial direction by a lock ring 3, thereby defining an annular oil chamber A between the inner cylinder 4 and the outer cylinder l. . In the center of the cap 5, an inner cylinder 4 is provided.
A sleeve hole 6 is bored through which the inside communicates with the annular oil chamber A via a passage 5A, and the upper end side of the sleeve hole 6 is formed into a tapered shape, so that the valve portion 12E of the pin 12 that retracts # is seated. It is seat 6A.

A piston 7 is slidably inserted into the inner cylinder 4, and the piston 7 has an oil chamber B serving as an upper chamber of the piston inside the inner cylinder 4;
The oil chamber C is defined as a lower chamber of the piston. The piston 7 is provided with an extension side damping force generation mechanism 8 and a contraction side damping force generation mechanism 9, and each of the damping force generation mechanisms 8.
9, the one on the extension side is configured to generate a higher damping force.

10 is fixed to the piston 7 via the lower end (the lower end is hollow) 11, and the upper end is fixed to the inside via the rod guide 2 and lock ring 3. 24. A piston rod protruding outward from the outer cylinder l,
A hollow hole 10A extending upward from the lower end is bored in the axial direction of the piston rod 10, and a locking portion 10B protruding from the upper end of the hollow hole 10A for engaging the end of a spring 13, which will be described later. ing. Further, in the radial direction of the piston rod 10, an oil passage 1 is located on the oil chamber B side and communicates with the hollow hole 10A.
0C is bored, and the oak 11 is provided with an orifice hole IIA having a smaller diameter than the hollow hole 10A.

Here, said hollow hole! The OA, oil passage 10C, and orifice hole 11A constitute a communication path that communicates the oil chambers B and C1111, and the effective cross-sectional area of this communication path can be changed by changing the passage area of the orifice hole 11A with a pin 12, which will be described later. It can be changed as appropriate.

Reference numeral 12 designates a pin having different diameters, which changes the effective cross-sectional area of the communication passage according to the stroke position of the piston 7, thereby making the generated damping force variable. The piston rod 10 is fitted onto the piston rod 10 via a spring 13 so as to be displaceable in the axial direction. Here, the pin 12 has a small diameter part IZA located on the toe side and formed with a diameter a, a large diameter part 12B located on the lower side and formed with a diameter A, and a part between the large diameter part 12B and the small diameter part 12A. The large diameter portion 12B is formed to have a slightly smaller diameter than the orifice hole 11A. A locking part 120 to which one end of the spring 13 is engaged is provided at the upper end of the small diameter part 12A, and a locking part 120 that is seated on the valve seat 6A of the oil chamber 6 is provided at the lower end of the large diameter part 12B. , 1'+A jL' A small diameter orifice hole 12F is provided in the portion 12E.

Thus, the pin 12 is suspended so as to be axially displaceable in the hollow hole 10A of the piston rod 1o via the spring 13 whose upper end is locked to the engaging IE portion 10B of the piston rod 1O, and inside the orifice hole 11A. When the small diameter portion 12A is located at the small diameter portion 12A, a small resistance force is applied to the oil passing through the small diameter portion 12A, thereby generating a small M damping force. Then, the screw 7 slides downward within the inner cylinder 4 to open the orifice hole 1. IA
When the large diameter portion 12B is located inside the orifice hole 11A, the passage area of the orifice hole 11A is reduced, and a large resistance force is applied to the oil passing therethrough, thereby generating a large damping force. on the other hand,
When the piston 7 slides downward, the valve portion 12E is seated on the valve seat 6A to communicate the annular oil chamber A and the oil chamber C through the orifice hole 12F. As a result, the oil passing through the oil chamber 6 is subjected to a large resistance force by the orifice hole 12F, and a large damping force is generated.

Next, the operation of the hydraulic shock absorber configured as described above will be explained.

First, the piston 7 is placed in a displaced state within the inner cylinder 4 as the vehicle height changes depending on the weight of the vehicle. That is, when the vehicle height is high, the piston 7 is displaced in the direction of the arrow,
When the vehicle height becomes lower, it is displaced in the direction of arrow E.

When the piston 7 is displaced in the direction of arrow E, the pin 12 is pressed downward by the spring 13, and the valve portion 12E of the pin 12 is seated on the valve seat 6A, and is seated inside the orifice hole 11A. The large-diameter portion 12B comes to be displaced, and the passage surface of the orifice hole 11A becomes smaller. On the other hand, the oil chamber 6 is also communicated with the oil chamber C only through the orifice hole 12F, so the oil chamber 6 side The passage surface clearance at is also reduced. In this state, when vibrations are applied to the vehicle and the piston rod 10 expands and contracts, the oil chambers B and C move into the oil passage 10.
c. The hollow hole 10A and the orifice hole 11A communicate through a communication path, and the effective cross-sectional area of the communication path becomes smaller at the orifice hole 11A. Since they are in communication only through the communication path and the orifice hole 12F, the oil passing through the communication path and the orifice hole 12F has a large resistance force, and a large damping force is generated.

Thus, when the vehicle is heavy and the height is low, a large damping force is generated and a hard ride can be provided. Then, when the moving speed of the piston rod 10 becomes faster, the extension side damping force generation mechanism 8 opens in the extension stroke, and the reduction side damping force generation mechanism 9 opens in the contraction stroke, so that a predetermined damping force is generated. The damping force can be changed as appropriate.

On the other hand, when the piston 7 is displaced in the direction indicated by the arrow, the pin 12 is pulled upward via the spring 13.
The valve portion 12E of the pin 12 is offset from the valve seat 6A, and the small diameter portion 12A of the pin 12 is located inside the orifice hole 11A, so that the passage area of the orifice hole IIA becomes large and the communication path As the effective cross-sectional area becomes larger, the passage area on the oil chamber 6 side also becomes larger. and,
When the piston rod 10 expands and contracts in this state, since the passage areas of the communication passage and the oil chamber 6 have become large, a small resistance force is applied to the oil passing through the communication passage and the oil chamber 6. , a small damping force is generated.

In this way, when the weight of the vehicle is light and the vehicle height is high, a small damping force is generated and a soft ride comfort can be provided. Even in this case, when the moving speed of the piston rod 10 becomes faster, the extension side and contraction side damping force generation mechanisms 8.9 open in the extension stroke and contraction stroke, respectively, and a predetermined 'g damping force is generated. This allows the damping force to be changed as appropriate. Even in this state, if large vibrations are applied to the vehicle,
If the piston 7 undergoes a large sliding displacement, the pin 1
The second valve portion 12E is seated on the valve seat 6A, and the orifice hole 11
The large diameter portion 12B is now located inside A, and a large damping force can be appropriately generated.

Furthermore, in this embodiment, since the pin 12 is held in the piston rod 10 via the spring 13 so as to be able to be displaced in the axial direction, the pin 12 can be easily assembled into the hollow hole 10A of the piston rod IO. This makes it possible to significantly improve assembly work and improve workability compared to conventional techniques. That is, in order to assemble the pin 12 into the hollow hole 10A, one end of the spring 13 is engaged with the locking portion 1zD of the pin 12 in advance, and the pin 12 is inserted into the hollow hole 1 together with the spring 13.
0A, and push the pin 12 deep into the hollow hole 10A, then insert the other end of the spring 13 into the hollow hole! O
The pin 12 can be locked in the locking part 10B provided at the upper end of the hole A, and the pin 12 can be easily assembled into the hollow hole 10A, improving workability.

〔Effect of the invention〕

As detailed above, according to the present invention, the pin for changing the effective cross-sectional area of the communication passage communicating between the piston upper chamber and the piston lower chamber is attached to the piston rod so as to be displaceable in the axial direction of the piston rod. Since the piston is held in place, the piston can be inserted into the inner cylinder with the pin pre-assembled in the piston rod, and workability can be greatly improved compared to the prior art. Further, since the effective cross-sectional area of the communication passage can be changed by the pin, the damping force can be changed appropriately depending on the stroke position of the piston, and the riding comfort of the vehicle can be improved.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention, and FIG.
FIG. 3 is a partial external view showing the main parts of the pin shown in the figure. l...outer cylinder, 4...inner cylinder, 6...oil chamber, 6A.
... Valve seat, 7... Piston, 10... Piston rod, 10A... Hollow hole, IOC... Oil path, 11...
・Nut, IIA... Orifice hole, 12r... Pin, 12A... Small diameter part, 12B... Large diameter part, 12E...
... Valve part, 12F... Orifice hole, 13... Spring, A... Annular oil chamber, B, C... Oil chamber. Figure 1

Claims (3)

[Claims] (1) an outer cylinder, an inner cylinder disposed within the outer cylinder to define an annular oil chamber between the outer cylinder and an oil passage communicating with the annular oil chamber at one end; a piston that is slidably inserted into an inner cylinder and defines the inside of the inner cylinder into an upper piston chamber and a lower piston chamber; one end is fixed to the piston, and the other end is connected to the inner cylinder and the outer cylinder. A piston rod protruding to the outside, a communication passage communicating between the upper chamber and the lower chamber via a hollow hole bored in the axial direction from one end of the piston rod, and an effective cross-sectional area of the communication passage being variable. In order to achieve this, there is provided a hydraulic shock absorber comprising pins of different sizes and diameters loosely fitted into the hollow hole, wherein the pin is held by the piston rod so as to be displaceable in the axial direction of the piston rod. . (2) Claim (1) wherein the pin is held on the piston rod via a spring provided in the hollow hole.
Hydraulic shock absorber described in ). (3) A valve part for opening and closing the oil passage and an orifice hole bored in the valve part are provided on one end side of the pin, and when the oil passage is blocked by the valve part, the oil passage is opened and closed through the orifice hole. Claim 1 (1) in which the lower chamber and the annular oil chamber are communicated with each other.
Hydraulic shock absorber described in ).