JPH10318320A - Gas filling part structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fill specified gas without entailing any fear of the lowering of sealing performance in a seal to be slidingly contacted with the outer boundary of a piston rod. SOLUTION: This gas filling part is composed of having a gas filling path 5b or the like, being made up in a space between the outer boundary of a lower end 5a in a packing case 5 covering a seal 3 to be slidingly contacted with the circumference of a piston rod 2 and the inner boundary of an opening end 6a in an outer cylinder 6 being set up at the peripheral side of a cylinder 1 and forming a reservoir chamber R in a gap with the cylinder 1, interconnected to the reservoir chamber R. In addition, it is also composed of making it communicate to the external side of the packing case 5 on the midway where the lower end 5a of the packing case 5 is pressed in the inner boundary side of the opening end 6a of the outer cylinder 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas filling structure in a hydraulic shock absorber used for sealing gas in a hydraulic shock absorber.

[0002]

2. Description of the Related Art There have been various proposals for sealing gas in a hydraulic shock absorber. For example, in the proposal shown in FIG. A jig G is inserted between the outer periphery of the piston rod 2 inserted so as to be able to protrude and retract and the inner periphery of the seal 3 slidably in contact with the outer periphery of the piston rod 2, and gas is formed into the inner periphery of the jig G Gas is injected into the cylinder 1 through the groove g, and after the gas is injected, the jig G is pulled out, whereby the interference of the seal 3 is restored and the gas is sealed.

According to this measure, there is an advantage that the gas can be sealed after the so-called assembly of the hydraulic shock absorber is completed. Further, as shown by an imaginary diagram in the drawing, the tip of the jig G is inserted deeply. When the gas is injected, there is an advantage that it is possible to remove the gas in order to adjust the pressure of the enclosed gas by using the jig G as it is.

However, according to this measure,
Since the seal 3 is expanded from the inner peripheral side to the outer peripheral side by the jig G, even if there is no fear that the durability of the seal 3 itself is reduced, the sealing property, that is, the sealing performance is easily reduced. Could be said to be.

That is, as shown in FIG. 11, the seal 3 has an oil lip portion 3a inside the cylinder 1 (not shown) which is the lower end in FIG. The oil lip portion 3a and the dust lip portion 3b are formed to have a dust lip portion 3b on the outer side of the cylinder 1, and the oil lip portion 3a and the dust lip portion 3b are pressed against the outer circumference of the piston rod 2 by the tightening force of the respective garter springs 4 from the outer circumference side. It is set as follows.

In particular, the dust lip portion 3b is
It must function to thoroughly prevent dust from the outside from entering the inner peripheral side of the seal 3 through the space between the inner periphery of the dust lip portion 3b and the outer periphery of the piston rod 2.

Therefore, it is preferable that the shape of the tip of the dust lip portion 3b is set so that dust from the outside hardly accumulates without scraping off the oil film that has reached the outer periphery of the piston rod 2. In case, 0.2
It is said that a radius of curvature from millimeter to 1.0 millimeter is applied.

Therefore, when observing the arrangement of the seal 3 in the hydraulic shock absorber after the completion of the assembly, it is not an exaggeration to say that the tip of the dust lip portion 3b is almost in close contact with the outer periphery of the piston rod 2. State.

Therefore, when the dust lip portion 3b whose tip is almost in close contact with the outer periphery of the piston rod 2 is to be expanded at the tip of the jig G, a so-called unreasonable force is applied to the tip of the dust lip portion 3b. That is,
The tip of the dust lip portion 3b is pushed into the inner peripheral side of the dust lip portion 3b together with the tip of the jig G. At this time, the tip of the dust lip portion 3b may be damaged or damaged. There is concern.

If the tip of the dust lip portion 3b is damaged, the dust lip portion 3b cannot sufficiently achieve its intended purpose, so that dust enters the inner peripheral side of the seal 3. In a case where dust is intruded, the outer periphery of the piston rod 2 may be damaged by dust, or the oil lip portion 3a may be abraded to cause oil leakage.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a predetermined seal without fear of a decrease in sealing performance of a seal sliding on the outer periphery of a piston rod. An object of the present invention is to newly provide a gas sealing portion structure that is optimal for enabling gas charging.

[0012]

In order to achieve the above-mentioned object, the structure of the gas filling portion structure according to the present invention basically comprises a packing for covering a seal slidably contacting the outer periphery of a piston rod from the outer peripheral side. In a hydraulic shock absorber in which a lower end of a case is disposed on an outer peripheral side of a cylinder and is inserted and sealed on an inner peripheral side of an open end of an outer cylinder forming a reservoir chamber with the cylinder, a packing case is provided. A gas injection passage communicating with the reservoir chamber is formed between the outer circumference of the lower end of the outer cylinder and the inner circumference of the open end of the outer cylinder, and the gas injection path connects the lower end of the packing case to the open end of the outer cylinder. It is assumed that it is communicated with the outer side of the packing case during press-fitting into the inner peripheral side of the part.

More specifically, the gas injection path is formed by processing the outer periphery of the lower end of the packing case, and preferably, the gas injection path is formed by the lower end of the packing case and the inner periphery of the open end of the outer cylinder. It is assumed that a gas-sealing seal is disposed between the two.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. As shown in FIG. The lower end of the packing case 5 that covers the seal 3 slidably contacting the outer peripheral side is disposed on the outer peripheral side of the cylinder 1 and the open end of the outer cylinder 6 that forms a reservoir chamber (not shown) with the cylinder. The present invention is embodied in a hydraulic shock absorber which is inserted and sealed on the inner peripheral side of the hydraulic shock absorber.

The gas filling portion structure has a gas injection path between the outer periphery of the lower end 5a of the packing case 5 and the inner periphery of the open end 6a of the outer cylinder 6, that is, in the illustrated embodiment, As shown in FIG. 2, it is assumed that a gas injection path including a cutout groove 5b formed on the outer periphery of the lower end 5a of the packing case 5 is formed.

This gas injection path is provided at the open end 6a of the outer cylinder 6.
Since it is better not to cause undue deformation on the outer circumference of the packing case 5, it is preferable that the packing case 5 is formed by processing the outer circumference of the lower end portion 5a.
As shown in FIG. 3, the lower end 5a of the packing case 5 is deformed so as to be slightly crushed from both opposing outer circumferential sides, instead of the notch groove 5b. And a gap 5c formed between the opening end 6a and the inner periphery of the opening end 6a.

Further, as shown in FIG. 4, the lower end 5a of the packing case 5 is deformed so as to be so-called beveled from four directions on the outer peripheral side, so that the inner periphery of the open end 6a of the outer cylinder 6 is formed. And a passage 5d formed between them.

On the other hand, in the present invention, the gas injection path is provided on the outer side of the packing case 5 while the lower end 5a of the packing case 5 is press-fitted into the inner peripheral side of the opening end 6a of the outer cylinder 6. It is said that it will be communicated.

The gas injection path is used after the predetermined press-fitting of the packing case 5 shown in FIG.
In any case before the end of the press-fitting of the packing case 5 shown in (1), it is needless to say that the packing case 5 communicates with the gas chamber portion R in the reservoir chamber formed between the cylinder 1 and the outer cylinder 6.

Incidentally, the structure of the peripheral part of the packing case 5 will be briefly described. First, a bump plate 7 is integrally connected to an upper end part 5e of the packing case 5, and a central part of the upper end part 5e. Is formed with a rod insertion hole 5f formed in the center of the bump plate 7 and communicating with a rod insertion hole 7a formed outside. It is needless to say that the piston rod 2 is inserted into the rod insertion holes 7a and 5f.

Next, the upper end, which is the opening end of the cylinder 1,
Although it is sealed with the bearing 8, it is assumed that the expanded upper end of the bearing 8 is located on the inner peripheral side of the lower end 5 a of the packing case 5.

The seal 3 is housed in the inner periphery on the upper end side of the packing case 5 in advance, and the inner periphery of the bearing 8 has a slight clearance (mark) around the outer periphery of the piston rod 2. (Not shown) is held.

Further, as described above, the space between the cylinder 1 and the outer cylinder 6 is set to the reservoir chamber having the gas chamber portion R. This reservoir chamber is located inside the lower end of the cylinder 1 (not shown). The lower oil chamber is connected to a lower oil chamber which is also defined by a piston in the cylinder 1 via a base valve portion disposed therein. Communicates with the upper oil chamber indicated by.

The gas filling portion structure according to this embodiment configured as described above enables gas to be filled in the hydraulic shock absorber through the following working steps.

That is, first, as shown in FIG. 5, in the hydraulic shock absorber, the lower end 5a of the packing case 5 is press-fitted into the inner peripheral side of the open end 6a of the outer cylinder 6 so as to be slightly inserted. Then, the jig G is set while maintaining the so-called temporary fixing state.

As a result, the jig G may have any structure as long as the jig G can realize gas encapsulation. However, each of the jigs G in this embodiment has a cylindrical shape. Outer jig G1 and inner jig G set in a shape
Consists of two.

An outer peripheral jig G1 is provided with a packing G3 on the inner periphery at the lower end, which is in close contact with the outer periphery near the open end 6a of the outer cylinder 6.
And has a gas flow path G4 for sealing gas.

The inner peripheral jig G2 is set so as to be movable along the piston rod 2 on the inner peripheral side of the outer peripheral jig G1. A packing G5 closely contacting the outer periphery of the rod 2 is provided on the inner periphery, and a packing G6 closely contacting the inner periphery of the outer peripheral jig G1 is provided on the outer periphery.

Incidentally, FIG. 5 and FIGS.
In the state shown in (1), the outer cylinder 6, which is the hydraulic shock absorber side, is maintained in a so-called fixed state in which the movement of the hydraulic shock absorber in the axial direction is prevented.

In the state shown in FIG. 5, the gas injection path formed by the cutout groove 5b formed on the outer periphery of the lower end 5a of the packing case 5 communicates with the outside of the packing case 5 at the upper end as described above. , A gas chamber portion R in the reservoir chamber formed between the outer cylinder 6 and the cylinder 1 at the lower end
Is in communication with

Therefore, under the condition shown in FIG. 5, gas from an external gas supply source (not shown) is supplied through the flow path G4 to the inner peripheral side of the outer peripheral jig G1, that is, to the outside of the packing case 5. And the gas supplied to the outside of the packing case 5 is caused to flow into the gas chamber portion R via the gas injection path.

Next, after the injection of the gas of the predetermined pressure into the gas chamber portion R is completed, as shown in FIG. 6, the outer peripheral jig G1 is left as it is, and an external force is applied to the inner peripheral jig G2. Then, the lower end 5a of the packing case 5 is finally pressed into the inner peripheral side of the open end 6a of the outer cylinder 6 via the bump plate 7.

By the final press-fitting of the packing case 5, the upper end of the gas injection path formed by the cutout groove 5 b is closed at the inner periphery of the opening end 6 a of the outer cylinder 6, and is blocked from the outside of the packing case 5. Therefore, the injected gas is sealed in the gas chamber portion R.

In this state, since the outer periphery of the lower end 5a where the notch groove 5b is not formed is in sliding contact with the inner periphery of the open end 6a, the gas supply source is separated from the outer jig G1. However, so-called gas leakage is not caused.

After the lower end 5a of the packing case 5 is pressed into the inner peripheral side of the opening end 6a of the outer cylinder 6, as shown in FIG. Jig G
1 and at the outer periphery of the opening end 6a of the outer cylinder 6,
For example, with the welding electrode M adjacent and the packing case 5
Is performed between the lower end 5a of the outer cylinder 6 and the open end 6a of the outer cylinder 6.

By this welding, the packing case 5 and the outer cylinder 6 are integrated and, at the same time, the gas is completely sealed in the gas chamber portion R, as long as the mechanical strength can be ensured. Instead of this welding, a roll caulking process from the outer peripheral side to the opening end 6a of the outer cylinder 6 may be used.

Then, the gas injection path is changed to the gap 5c shown in FIG.
Alternatively, in the case of the passage 5d shown in FIG. 4, the measure of roll caulking is effective, but it goes without saying that welding may be added to this roll caulking.

As described above, when the gas filling portion structure according to the present invention is used, when the gas is injected and filled in the hydraulic shock absorber, the inner circumference of the seal 3 and the piston rod are filled as in the conventional case described above. There is no need to insert the jig G between the outer periphery of the jig 2 and the jig G.

Therefore, the diameter of the rod insertion hole 7a formed in the center of the bump plate 7 and the diameter of the rod insertion hole 5f formed in the upper end 5e of the packing case 5 are determined by the jig G
, That is, as compared with the conventional case shown by a broken line in FIG.
A smaller diameter can be set.

As a result, the amount of dust entering the inner periphery on the upper end side of the packing case 5 through the rod insertion holes 7a and 5f, that is, the dust lip portion 3 in the seal 3
b, the amount of dust stored at the upper end of the piston rod 2 can be minimized, and a large amount of dust accumulates at the upper end of the dust lip portion 3b. Can also be reduced.

FIGS. 8 and 9 show another embodiment of the gas filling portion structure according to the present invention. In this gas filling portion structure, the lower end portion 5a of the packing case 5 and the outer cylinder 6, a gas sealing seal 10 is arranged between the opening end 6a and the inner periphery of the opening end 6a.

In the embodiment shown in FIG. 8, the gas sealing seal 10 is held on the lower end 5a side of the packing case 5, and in the embodiment shown in FIG. In any case, the gas is allowed to flow from the outside into the gas chamber portion R in the reservoir chamber through the gas injection path formed by the notch groove 5b, but the reverse flow is maintained. The check seal structure is set to block.

To explain a little, the gas sealing seal 10 shown in FIG. 8 is formed in a short tubular shape as a whole, and a rubber 10b is molded around the outer periphery of a core material 10a formed in a tubular shape. The lower end of the rubber 10b is
c is set.

It is assumed that the upper end side is press-fitted into a housing recess 5g formed on the inner periphery of the lower end portion 5a of the packing case 5,
At this time, it is assumed that the core material 10a is inserted into the outer periphery on the upper end side of the bearing 8, and the lip portion 10c is adjacent to the outer cylinder 6 below the opening end 6a.

A gas sealing seal 10 shown in FIG. 9 has a core 10a having a cross section set to an angle,
and a rubber 10b molded on a so-called outer peripheral side of the rubber 10b.
0c is set.

The lower end, which is the outer diameter side, is positioned so as to be pressed into a housing recess 6b formed near the lower end of the opening end 6a of the outer cylinder 6, and at this time, the lip 10c is attached to the lower end of the packing case 5. It is said that it is adjacent to the inner circumference of.

Since the inner periphery of the lower end of the packing case 5 is previously set to a tapered surface, when the lower end 5a of the packing case 5 is press-fitted into the inner peripheral side of the open end 6a of the outer cylinder 6, It goes without saying that the above-mentioned lip portion 10c interferes with the lower end of the packing case 5 and does not cause so-called bending.

Therefore, in any of the embodiments shown in FIGS. 8 and 9, when the above-described gas sealing seal 10 is provided, the packing case 5 including the gas injection path is provided. This is advantageous in that it facilitates dimensional control between the lower end of the outer cylinder 6 and the open end 6a of the outer cylinder 6 and can contribute to an improvement in productivity.

[0049]

As described above, according to the present invention, in filling a predetermined gas into the inside of the hydraulic shock absorber, it is necessary to perform an operation of expanding a seal slidingly contacting the outer periphery of the piston rod. Therefore, the dust lip portion of the seal does not expand at the tip of the jig, so that the tip of the dust lip portion is not damaged or damaged. The durability and the sealing performance of the seal having the above can be guaranteed as set.

Further, according to the present invention, since the gas injection path is formed by processing the outer periphery of the lower end portion of the packing case, the desired object can be achieved only by a slight processing of the existing parts. Therefore, it does not cause a significant change in the working process, and thus does not cause an economic disadvantage in the production process.

When a gas-tight seal is provided between the lower end of the packing case and the inner periphery of the open end of the outer cylinder, the seal between the packing case and the outer cylinder including the gas injection path is provided. This makes it easier to manage the dimensions between them and can contribute to an improvement in productivity.

As a result, according to the present invention, there is an advantage that it is optimal to enable a predetermined gas filling without fear of deterioration in the sealing performance of the seal sliding on the outer periphery of the piston rod in the hydraulic shock absorber. There is.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view partially showing a state in which a gas filling portion structure according to an embodiment of the present invention is embodied in a hydraulic shock absorber.

FIG. 2 is a cross-sectional view showing one embodiment of a gas injection path formed between a packing case and an outer cylinder.

FIG. 3 is a view showing a gas injection path according to another embodiment, similarly to FIG. 2;

FIG. 4 shows a gas injection path according to still another embodiment in FIG.
FIG.

FIG. 5 is a longitudinal sectional view partially showing one step of filling gas into the hydraulic shock absorber with the gas filling portion structure according to the present invention.

FIG. 6 is a view showing a step subsequent to the step shown in FIG. 5, similarly to FIG. 5;

FIG. 7 is a view showing a step that follows the step shown in FIG. 6 in the same manner as in FIG. 6;

FIG. 8 is an enlarged partial longitudinal sectional view showing a state in which another embodiment of the gas filling portion structure according to the present invention is embodied in a hydraulic shock absorber.

FIG. 9 is a view showing a state in which still another embodiment of the gas filling portion structure according to the present invention is embodied in a hydraulic shock absorber, similarly to FIG. 8;

FIG. 10 is a longitudinal sectional view partially showing a gas sealing portion structure as a conventional example in a state where gas is sealed.

FIG. 11 is an enlarged longitudinal sectional view showing a seal slidably contacting the outer periphery of a piston rod in the hydraulic shock absorber.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston rod 3 Seal 5 Packing case 5a Lower end 5b Notch groove as gas injection path 5c Gap as gas injection path 5d Passage as gas injection path 6 Outer cylinder 6a Open end 10 Gas sealing seal

Claims (2)

[Claims] An opening end of an outer cylinder which is disposed on an outer peripheral side of a cylinder and forms a reservoir chamber with the cylinder, wherein a lower end of a packing case which covers a seal slidably contacting the outer periphery of the piston rod from the outer peripheral side is provided. In the hydraulic shock absorber inserted and sealed on the inner peripheral side of the portion, a gas injection passage communicating with the reservoir chamber is formed between the outer periphery of the lower end of the packing case and the inner periphery of the open end of the outer cylinder. The gas injection path is communicated with the outside of the packing case during the press-fitting of the lower end of the packing case into the inner peripheral side of the opening end of the outer cylinder. 2. The gas-sealed portion structure according to claim 1, wherein a gas-tight seal is disposed between a lower end of the packing case and an inner periphery of an open end of the outer cylinder.