JPH0247789Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a position-dependent damping force mechanism used in motorcycles, in which the damping force increases during the extension stroke of a pressurized reaction.

(Prior Art) This type of damping force position-dependent mechanism is known from, for example, Japanese Patent Laid-Open No. 52-95438. This known mechanism has disadvantages such as a large number of machining steps because it is necessary to provide a large number of small holes in the push rod, a low strength of the push rod itself, and unstable guidance of the spring for the push rod. Also, in this known mechanism, the plunger 1
Since the spring 18 is arranged around the outer periphery of the piston, there is a favorable aspect in that a throttling effect is exhibited by reducing the distance between the lines at maximum compression, but the orifice opening is closed due to the buckling of the spring, and the There was a problem with inconsistent flow of hydraulic oil.

(Problems of the invention) The present invention eliminates the drawbacks associated with the prior art, namely, increases the strength of the push rod, stabilizes the guidance of the push rod and the guidance of the spring that biases the push rod, and provides suitable damping characteristics. The challenge is to create a pressurized reaction.

Embodiments of the present invention will be described in detail based on the drawings.

Embodiment The position-dependent damping force mechanism 4 according to the invention is constructed in the form of a throttle valve in the pressure reaction 1.

The pressurized reaction 1 has a position-dependent damping force mechanism 4 between the upper bracket 2 and the lower bracket 3.
It is equipped with

The upper bracket 2 is connected to the piston 5 via a cap 6. The cap 6 is connected to a flange 9 via a seal ring 7 and a snap ring 8,
The cap 6 is coupled so as to be prevented from moving upward, and the flange 9 is fixed to the inner end of the outer cylinder 10. A spring receiver 13 is disposed at the inner lower end of the cylinder 11 so as to be guided into the outer cylinder 10 via a snap ring 12 fitted into a ring groove 11a and prevented from engaging and disengaging downward in the axial direction. The lower end of the spring 14 is supported by the spring receiver 13, and the upper end of the spring 14 is supported by another spring receiver 15.

The spring receiver 15 is fitted onto the cylinder 11 and is prevented from moving upward by a snap ring 16 fixed to the cylinder 11.
A cap 17 is fixed to the upper end of the cylinder 11, and the cap 17 is provided with a small hole 17a for venting air. The piston rod 5 is fixed to the upper bracket 2 via a cap 17.

A rod guide case 18 is arranged on the piston rod 5 near the cap 17, and the rod guide case 18 is prevented from moving upwardly on the piston rod 5 by a snap ring 19 on the inner surface of the cylinder 11. A dust seal 20 is attached to the rod guide case 18.

An oil seal 21 is disposed on the piston rod 5 adjacent to the rod guide case 18, and the oil seal 21 is covered by an oil seal cover 22 on its outer periphery and on one side in the axial direction.

An oil seal 23 is provided on the outer periphery of the oil seal cover 22 and is connected to the inner surface of the cylinder 11.

A rebound rubber 24 is fitted in the region of the lower free end of the piston rod 5. The piston rod 5 is provided with a slightly smaller diameter area 5a via the step. A valve stopper 25 is arranged on this step, followed by a plurality of valve plates 26 including plates of different diameters. A piston 27 is disposed next to a valve plate 26 in the small diameter portion 5a of the piston 5, followed by a plurality of valve plates 28 including plates of different diameters, which are tightened with a nut 30 via a valve washer 29. It is being The piston rod 5 is screwed into the nut 30 at the threaded portion 5b. The piston 27 penetrates in the axial direction,
and a small hole 2 opening in the area of the valve plate 26
7a, penetrating obliquely to the axis, valve plate 28
A small hole 27b that opens in the range of , a ring groove 27c inside the piston 27, and a small hole 2 that communicates with the ring groove 27c.
It is equipped with 7d. The piston 27 has a piston ring 31 on its outer circumference.

As shown on an enlarged scale in FIG. 2, a hole 5d for accommodating a push rod 32 is provided in the lower area of the piston rod 5, and this hole 5d is connected to the piston ring by a small radial hole 5c in the area of the piston 27. It communicates with the ring groove 27c of No. 27. A guide bush 33 for guiding the push rod 32 is fitted into the hole 5d in a region near the opening. In the upper region of the push rod 32, it is tapered 32a to increase the cross-sectional area and thus to reduce the flow cross section between it and the guide bush 33, so that the cross section of the push rod 32 is D-shaped. ing. A hole 32b is provided in the upper region of the push rod 32, in which a spring 34 is accommodated (FIG. 2).

A spring guide 35 passes through the spring 34, and the spring guide 35 is connected to the spring 3.
4 has a head that supports the upper end of the spring 34 to prevent it from coming off, and the lower end of the spring 34 is connected to the hole 32.
It is supported by the low b. Spring guide 35
The head 35a of the piston rod 5 follows the hole 5d of the piston rod 5 and is supported by the bottom of a hole 5e having a smaller diameter. The push rod 32 is provided with a snap ring 36 at its upper end to prevent it from coming off.

A bottom cap 37 is fixed to the lower end of the cylinder 11, and an oil chamber 38 is installed inward of the cylinder 11 on top of the bottom cap 37 and is fixed by a ring-shaped bead 11a of the tank 11. ing. The oil chamber 38 has a small hole 38a,
The lower end of the push rod 32 always presses against the upper end of the oil chamber 38. A snap ring 39 is fixed to the inner surface of the oil chamber 38, which allows the cap 4 to
0 is prevented from moving axially downward.

The cap 40 has a center hole 40a.
A nipple 41 is screwed into 0a.

This nipple 41 is used as a connection port for charging high pressure gas. Center hole 4 of cap 40
A ball 42 is arranged on the end face of the cap 40, and a bag 43 is irremovably fitted onto the outer periphery of the cap 40.
The center hole 40a is opened by the gas pressure of the high pressure gas 44 inside.
It is crimped and occluded.

The pressurized reaction according to the present invention works as follows.

(Extension Stroke) In the illustrated state, the pressurized reaction 1 is compressed to the minimum length.

In this case, the bag 43 is compressed to a minimum volume,
The maximum amount of oil is accommodated in the oil chamber 38.

During the extension stroke of the pressurized reaction 1, the cylinder 11 and the lower bracket 3 move together with the piston rod 5.
move downward against. At this time, the rod guide case 32, oil seal 21, and oil seal cover 22 also move downward on the piston rod 5 together with the cylinder 11. As a result, the push rod 32 advances from the hole 5d of the piston rod 5 one after another. At this time, the taper shape 3 of the push rod 32
Due to the reduction in the flow cross-sectional area between push rod 32 and guide bush 33 due to push rod 2a, the damping force between push rod 32 and hole 5d increases. On the other hand, oil passes through the small hole 27b of the piston 27, pushes up the valve plate 28, and flows from the upper chamber of the piston 27 to the lower chamber.

At the time when the pressurized reaction 1 reaches its maximum length, the cross-sectional area of flow between the push rod 32 and the guide bush 33 due to the tapered shape 32a of the push rod 32 is minimized, so that the maximum damping force is generated. At this time, the bag 43 is inflated to its maximum capacity. The damping force between the small hole 27b of the piston 27 and the valve plate 28 is constant. When advancing from the hole 5d of the push rod 32, the spring 34 is stably guided and expanded by the spring guide 35, so that the push rod 32
It is ensured that the operation of the damping force is smooth and that the damping force changes smoothly.

(Compression Stroke) When the pressure reaction 1 changes from its maximum length to the illustrated minimum length, the damping force is regulated as follows.

The push rod 32 is pushed deeper into the hole 5d from the state in which it is pushed out from the hole 5d. In this process, the push rod 32 increases the flow cross-sectional area due to the tapered shape 32a between the push rod 32 and the hole 5d.

On the other hand, oil passing through the small hole 27a of the piston 27 pushes up the valve plate 26 and flows upward from the bottom of the piston 27. As a result, the tapered shape 32a of the push rod 32 produces a gradually smaller damping force depending on the position of the push rod 32, and a certain flow resistance is produced between the small hole 27a of the piston 27 and the valve plate 26. At this time, the bag 43 is compressed to its minimum capacity.

(Effect of the invention) According to the invention, the damping force position-dependent mechanism is provided with a mechanism in which the cross-sectional area of the tapered shape of the push rod changes, so that the function corresponding to the damping force adjustment square hole of the position-dependent mechanism of the pressurized reaction is achieved. achieved. That is, the flow of hydraulic oil between the upper and lower chambers of the pressurizing piston can be set in proportion to the position. The spring is housed inside the push rod, and the flow path is provided on the outer periphery of the push rod to communicate the upper and lower chambers of the piston, so that the flow path is not obstructed by the spring, and the spring is housed in a hole formed inside the push rod. The effect is that the installation length can be shortened.
During the extension stroke of the pressurized reaction, the push rod is reliably centered by the cylindrical portion and gradually advances from the piston rod, but since the push rod is provided with a taper with a D-shaped cross section, the push rod is stably guided and moves forward from the guide bush. As the clearance between the damping force changes and the position-dependent variation of the damping force occurs continuously, a suitable damping force characteristic can be ensured.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the pressurized reaction according to the present invention, and FIG. 2 is a partially enlarged view of the valve portion. Symbols in the figure: 1...pressure reaction, 5...
Piston rod, 5d... hole, 32... push rod, 32a... hole, 32b... taper, 34
... Spring, 35 ... Spring guide, 3
8... Oil room.

Claims (1)

[Scope of utility model registration request] The lower part of the piston rod 5 is provided with a hole 5d that opens at the lower end, in which the push rod 32 is guided movably in the axial direction by a guide bush 33, and the upper part of the push rod 32 has a hole that opens at the upper end. 32a, the outer periphery of which is tapered so that the flow cross-sectional area of the push rod 32 decreases toward the upper end, and a spring guided by a spring guide 35 is installed in the hole 32a. 34 is loaded, and the lower end of the push rod 32 is always crimped to the upper end of the oil chamber 38, so that the damping force is equal to the compression and extension stroke of the pressure reaction 1 during the compression and extension strokes of the pressure reaction 1. A position-dependent damping force mechanism, characterized in that the damping force gradually decreases and gradually increases depending on the position.