JPS6225557Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a gas filling mechanism for a hydraulic shock absorber, and in particular, gas is filled from a gas filling hole drilled in the cylinder when a piston rod guide is assembled to the cylinder, and the gas is sealed between the rod guide's O-ring and the rod guide. This invention relates to a gas filling mechanism that eliminates the need for an air valve by keeping the cylinder airtight with purling.

A type of hydraulic shock absorber that seals gas in a cylinder generally has an air valve installed in the cylinder body or piston rod guide at the end of the cylinder, and gas is sealed from this air valve. This not only complicates machining and increases costs, but also causes various problems in terms of installation space because the valve protrudes outside the cylinder.

This invention was made to solve the above problem, and its purpose is to fill the cylinder with gas without using an air valve, and after filling the cylinder, the cylinder can be kept airtight using the O-ring and stopper ring of the rod guide. An object of the present invention is to provide a gas filling mechanism for a hydraulic shock absorber.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

As shown in Fig. 1, the hydraulic shock absorber connects a piston 2 fixed to the tip of a piston rod 1 to a cylinder 3.
A spring 4 is stretched between the cylinder 3 and the rear end of a rod 1 which is slidably fitted into the cylinder 3 and extends to the outside from one end of the cylinder 3. A rod guide 6 is fitted inside a cover 5 on the open end side of the cylinder 3 from which the piston rod 1 protrudes to keep the inside of the cylinder airtight.

In the hydraulic shock absorber in which the rod guide 6 is fitted to the open end of the cylinder 3, the features of the present invention are as shown in an enlarged view in FIG.
A ring groove 8 for locking the stopper ring 7 is carved in the inner circumferential wall surface slightly inward from the open end of the cylinder 3, and a gas filling hole 9 is bored in the ring groove 8 to communicate the inside and outside of the cylinder 3. with cylinder 3
Two O-rings 10a and 10b are provided at a constant distance _d1 on the outer circumference of the rod guide 6 which is fitted into the open end of the rod guide 6. Preferably, the ring groove 8
It is preferable that the inner step portion is an inclined surface expanding toward the inner wall of the cylinder. O-ring 10a, 1 of rod guide 6
The distance d ₁ between 0b and 0b is smaller than the distance d ₂ from the open end of the cylinder 3 to the ring groove 8, so that when installing the rod guide 6 into the cylinder 3, the O
At least one of the rings 10a and 10b is located between the end of the cylinder 3 and the ring groove 8 to seal the gap 11 between the cylinder 3 and the guide 6. Moreover, these O-rings 10a,
The rod guides 10b are fitted into grooves 11a and 11b formed on the outer circumference of the rod guide 6, respectively, so as to be engaged therewith.

Since the present invention has the above-described structure, when filling gas into the cylinder 3, the rod guide 6 is inserted from the open end of the cylinder 3 as shown in Fig. 3a, and the gas is filled into the cylinder 3.
With at least one of the rings 10a and 10b in contact with the inner circumferential wall of the cylinder 3, a gas filling plug (not shown) is inserted into the gas filling hole 9 to seal gas into the cylinder 3 to maintain a constant pressure.

When the pressure inside the cylinder 3 reaches a constant level, the rod guide 6 is press-fitted into the cylinder 3, as shown in FIG. 3b. In this case, two O-rings 10a, 10b
Since the distance d ₁ is smaller than the distance d ₂ from the end of the cylinder 3 to the ring groove 9, the front O-ring 10a faces the ring groove 8 on the inner circumferential wall of the cylinder, as shown in FIG. 3b. Even if the gas inside the cylinder flows in the direction of the arrow, the rear O-ring 10b contacts the inner peripheral wall of the cylinder and closes the gap 11, so that the gas does not flow out from the end of the cylinder. There is no risk of it leaking.

Moreover, when the rod guide 6 is further pushed into the cylinder 3 as shown in FIG. 3c, the rear O-ring 10b
faces the ring groove 8, and a gap 11 is created between the ring groove 8 and the front O-ring 1.
0a is the gap 11 between the cylinder 3 and the rod guide 6
Since it is sealed, gas leaks cannot occur.

Furthermore, as shown in FIG. 3c, when a stopper ring 7 that expands outwardly due to elasticity is fitted to the rear end of the rod guide 6, preferably the stepped locking end 12, and inserted into the cylinder 3 together with the rod guide 6, the stopper ring 7 is the ring groove 8 as shown in Figure 3d.
It bulges outward at a position facing the ring groove 8 and is fitted into the ring groove 8. That is, the stop ring 7 comes into contact with the locking end 12 of the rod guide 6 and locks the rod guide 6 in the cylinder 3.

As described above, according to the present invention, there is no need for an air valve for filling gas in a gas-filled hydraulic shock absorber, so that processing and assembly are extremely simple, and the shape is also extremely simple. Moreover, since the gas filling hole is formed in the ring groove, the O-ring will not be damaged when the rod guide is pushed into the cylinder.
Further, since gas can be filled in and kept airtight with a simple structure and assembly, production of this type of shock absorber can be significantly streamlined.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a hydraulic shock absorber using the present invention, FIG. 2 is an enlarged view of the main part of FIG. 1, and FIGS. 3a to 3d are explanatory views showing the gas filling process. 1... Piston rod, 3... Cylinder, 6...
... Rod guide, 7... Stopper ring, 8...
Ring groove, 9... Gas filling hole, 10a, 10b...
...O-ring.

Claims (1)

[Scope of utility model registration request] A hydraulic shock absorber in which a piston fixed to the tip of a piston rod is slidably fitted into a cylinder, and a rod guide is airtightly engaged near the cylinder open end of the rod extending outside the cylinder via an O-ring and a stopper ring. In the cylinder 3, a ring groove 8 for locking the stopper ring 7 is carved on the inner circumferential wall surface near the open end of the cylinder 3, and a gas sealing hole 9 communicating with the inside and outside of the cylinder 3 is bored in the ring groove 8. At the same time, two O-rings 10a and 10b are fitted around the outer periphery of the rod guide 6 with a distance _d1 smaller than the distance _d2 between the open end of the cylinder and the ring groove 8, so that the gas from the gas filling hole 9 is During gas filling, at least one O-ring of the rod guide 6 facing the open end of the cylinder closes the gap 11 between the cylinder 3 and the rod guide 6 on the distal end side of the ring groove 8, and after gas filling, the rod guide 6 is placed inside the cylinder 3. Two O-rings 10a, 10b when inserted
The gas filling mechanism of the hydraulic shock absorber closes the gap 11 between the cylinder 3 and the rod guide 6 behind the ring groove 8, and the stop ring 7 is engaged with the ring groove 8.