JPH1113818A - Gas sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To seal gas without decreasing seal performance in an oil seal, in the case of sealing gas in a hydraulic shock absorber by inserting a tip end part of a gas sealing jig between an internal periphery of a dust lip part in the oil seal and an external periphery of a piston rod. SOLUTION: In a gas sealing device sealing prescribed gas in a hydraulic shock absorber through a gas passage 11a formed in an internal periphery of a tip end part 11 in a gas sealing jig 10 inserted between an internal periphery of a dust lip part 3b in an oil seal 3 received to be mounted in an internal peripheral side of a packing case 5 and an external periphery of a piston rod 2, the device comprises a screw-shaped guide groove 21a in an internal periphery and a guide ring 20 secured to a hydraulic shock absorber side, and screwed tip end part 11 in the gas sealing jig 10 to the screw-shaped guide groove 21a of this guide ring 20. Further, in a tip end of the tip end part 11 in the gas sealing jig 10, an insertion part 11b is protrudedly formed extending along an axial line direction in this tip end part 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a gas filling device which enables gas to be filled 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. The tip 1 of the gas sealing jig 10 is located between the outer circumference of the piston rod 2 inserted so as to be retractable and retractable and the inner circumference of the oil seal 3 slidably contacting the outer circumference of the piston rod 2.
1 is inserted into the cylinder 1 through a groove 11a as a gas passage formed in the inner periphery of the tip portion 11 of the gas sealing jig 10, and after the gas is sealed, the gas sealing jig 10
By pulling out the front end 11 of the oil seal 3, the interference of the oil seal 3 is restored and gas is sealed in the hydraulic shock absorber.

According to this measure, there is an advantage that the gas can be sealed after the so-called assembling of the hydraulic shock absorber is completed. Further, as shown by an imaginary diagram in the figure, the distal end portion 11 of the gas sealing jig 10 is closed. When the gas is sealed so as to be inserted deeply, there is an advantage that the gas can be extracted in order to adjust the pressure of the gas sealed in the hydraulic shock absorber as it is.

However, according to this measure,
Since the tip 11 of the gas sealing jig 10 is forcibly inserted between the inner periphery of the oil seal 3 and the outer periphery of the piston rod 2, there is a fear that the durability of the oil seal 3 itself may be reduced. Even if not, there is a possibility that it can be said that the sealing performance, that is, the sealing performance is easily reduced.

That is, as shown in FIG. 7, the oil seal 3 has a dust lip portion 3b and an oil lip portion 3c integrally connected to a main body portion 3a having a metal core 31. A dust lip portion 3b on the upper end side in FIG.
Face the outside of the cylinder 1 (not shown), and the oil lip 3c, which is the lower end in the figure, faces the inside of the cylinder 1.

The dust lip portion 3b and the oil lip portion 3c are set so as to have a predetermined interference. However, the tightening force of each garter spring 4 from the outer peripheral side, which is the back side of each of them. Is set so as to be pressed against the outer periphery of the piston rod 2.

By the way, especially, the dust lip portion 3b
It must function so as to thoroughly prevent external dust from entering the inner peripheral side of the oil seal 3 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 portion of the dust lip portion 3b is set so that dust from the outside hardly accumulates without scraping off the oil film that reaches the outer periphery of the piston rod 2. In the case of
It is said that a radius of curvature of 0.2 mm to 1.0 mm is applied.

Therefore, when observing the arrangement of the oil seal 3 in the hydraulic shock absorber after the assembly is completed, it can be said that the pointed end of the dust lip portion 3b is almost in close contact with the outer periphery of the piston rod 2. It is in a state of exaggeration.

Therefore, the distal end portion 11 of the gas sealing jig 10 is provided between the inner periphery of the dust lip portion 3b and the outer periphery of the piston rod 2 in a state where the tip portion is almost in close contact with the outer periphery of the piston rod 2. When inserting, the so-called unreasonable force is applied to the tip portion of the dust lip portion 3b. Therefore, the tip portion of the dust lip portion 3b is together with the tip portion 11 of the gas sealing jig 10 in the dust lip portion 3b.
In other words, there is a risk that the tip of the dust lip portion 3b may be damaged or broken at this time.

If the tip of the dust lip portion 3b is damaged, the dust lip portion 3b cannot sufficiently achieve its intended purpose. Therefore, dust is generated on the inner peripheral side of the oil seal 3. If it becomes easy to invade and further dust invades, if the outer periphery of the piston rod 2 is damaged by dust or the oil rod lip portion 3a is worn due to the damage in the piston rod 2, oil leakage is caused. There is a fear that it will invite.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a gas sealing jig between an inner periphery of a dust lip portion of an oil seal and an outer periphery of a piston rod. The object of the present invention is to provide a gas filling device which is optimal for filling gas without lowering the sealing performance of an oil seal when a gas is sealed in a hydraulic shock absorber by inserting a tip portion of the gas sealing device. .

[0013]

Means for Solving the Problems To achieve the above-mentioned object, the construction of the present invention is basically applied to the inner periphery of the dust lip portion of the oil seal housed on the inner periphery of the packing case and the piston. In a gas filling device that fills a predetermined gas into a hydraulic shock absorber through a gas passage formed in an inner periphery of a tip portion of a gas filling jig inserted between the outer periphery of a rod, a screw guide is provided on an inner periphery. The guide ring has a groove and is fixed to the hydraulic shock absorber side, and the tip of the gas sealing jig is screwed into the spiral guide groove of the guide ring, and the gas sealing jig is formed. It is assumed that an insertion portion extending along the axial direction of the distal end portion is formed at the distal end of the distal end portion of the tool.

At this time, it is preferable that the distal end of the distal end is spirally inclined from one side of the insertion section toward the other side.

It is preferable that the gas passage formed on the inner periphery of the distal end has an open end opened at the distal end of the insertion portion, and the number of gas passages is more than one. May be set.

In the oil seal, a stress concentration concave portion is formed between the dust lip portion and the main body portion connecting the dust lip portion, and the dust lip portion is expanded by the tip of the gas sealing jig. It may be set so that the dust lip portion can be easily expanded at the time of operation.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. As shown in FIG. 1, a gas filling device according to one embodiment of the present invention The guide ring 20 is set in a hydraulic shock absorber configured as described below so that a predetermined gas can be sealed in the hydraulic shock absorber.

That is, first, the hydraulic shock absorber has a packing case 5 that accommodates an oil seal 3 slidably contacting the outer periphery of the piston rod 2 so as to cover the oil seal 3 from the outer peripheral side. And a reservoir chamber (not shown) having a gas chamber portion R formed between the outer casing 6 and the lower end 5a of the packing case 5 at the open end 6a of the outer casing 6. Are inserted in a press-fit state on the inner peripheral side and sealed by welding or the like.

The oil seal 3 basically has
Since the configuration is the same as that of the above-described conventional example (see FIG. 7), portions having the same configuration are denoted by the same reference numerals in FIGS. 2 and 3 and detailed description thereof is omitted. I do.

In the packing case 5, a bump plate 7 is integrally connected to an upper end portion 5b, and rod insertion holes 5c, 7 formed in the center portion together with the bump plate 7.
The piston rod 2 is inserted through a.

Incidentally, in the illustrated embodiment,
The guide ring 20 is adjacent to the bump plate 7 when the gas sealing device is set, and the guide ring 20 is fixed in such a state that the guide ring 20 is prevented from moving toward the hydraulic shock absorber.

When the gas filling device is set in the hydraulic shock absorber, the gas filling jig 1 is inserted into the rod insertion holes 5c and 7a.
0 is inserted through the outer periphery of the piston rod 2 while the guide ring 20 is screwed around the outer periphery thereof.

The upper end, which is the opening end of the cylinder 1,
Although the bearing 8 is sealed, the enlarged upper end of the bearing 8 is assumed to be fitted on the inner peripheral side of the lower end 5 a of the packing case 5. Passages 8a and 8b are formed from the upper end and the outer periphery, and the bearings 8 are formed by the passages 8a and 8b.
And the gas chamber portion R in the reservoir chamber can communicate with each other.

A bush 9 is held on the inner periphery of the bearing 8 with the inner periphery facing the outer periphery of the piston rod 2 with a slight gap (not shown).

Further, as described above, the reservoir between the cylinder 1 and the outer cylinder 6 is set as a reservoir having a gas chamber portion R. 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 device set in the hydraulic shock absorber constructed as described above has the gas filling jig 10 and the guide ring 20 as described above. The distal end portion 11 of the jig 10 is connected to a state in which the distal end portion 11 is screwed around the inner periphery of the guide ring 20, and the distal end portion 11 spirally rotates when the guide ring 20 is prevented from rotating. The guide ring 20 is set so as to protrude and retract.

The gas filling jig 10 is connected to the guide ring 20.
As shown in FIG. 3, the tip 11 of the gas sealing jig 10 moves between the inner circumference of the dust lip portion 3 b of the oil seal 3 and the outer circumference of the piston rod 2. It is set so that it is inserted in between.

The gas sealing jig 10 will be described in a state where the tip 11 is inserted between the inner periphery of the dust lip portion 3b of the oil seal 3 and the outer periphery of the piston rod 2. It is set so that gas can be sealed in a hydraulic shock absorber. Specifically, for example, it is configured as disclosed in Japanese Patent Publication No. 61-16859.

That is, as shown in FIG. 2, the gas sealing jig 10 has a tip portion inserted between the outer circumference of the piston rod 2 and the inner circumference of the oil seal 3 which is in sliding contact with the outer circumference of the piston rod 2. 11 and the tip 11
A groove 11a serving as a gas passage is formed on the inner periphery of the gas filling jig 10. The groove 11a is disposed outside and communicates with a gas supply / discharge source (not shown) connected to the gas sealing jig 10. It has become.

The gas filling jig 10 has an appropriate size so that the tip of the tip 11 which is the lower end in the figure comes into contact with the tip of the dust lip 3b of the oil seal 3 in a slippery manner. The open end of the groove 11a as the above-mentioned gas passage appears between the outer periphery of the piston rod 2 and the pointed end of the dust lip portion 3b so as to follow the curved end. Empty part A
It is set to face.

Incidentally, in the illustrated embodiment, the above-mentioned groove 11a is provided with a front end portion 11 as shown in FIG.
Is provided at one location on the inner circumference of, i.e., singularly, but may be provided at a plurality of locations, that is, at a plurality of locations as shown in FIG. Of course it's good.

On the other hand, as shown in FIG. 4, the tip 11 of the gas sealing jig 10 has an axial direction at the tip 11 which is the lower end in the drawing and which is also vertical in the drawing. And an insertion portion 11b protruded so as to extend along.

In the embodiment shown in the drawings, the groove 11a as the above-mentioned gas passage is formed on the inner surface of the insertion portion 11b, and the open end of the groove 11a is formed at the tip of the insertion portion 11b. It is said that the opening is made.

The tip of the insertion portion 11b has a curved shape having an appropriate dimension so that the tip portion of the dust lip portion 3b of the oil seal 3 is slidably contacted similarly to the tip of the tip portion 11 described above. Set to the end.

Further, the opening end of the groove 11a at the tip of the insertion portion 11b is set so as to face the space A so as to follow the tip of the insertion portion 11b.

Therefore, in the gas sealing jig 10 of this embodiment, the tip of the insertion portion 11b formed at the tip of the tip portion 11 is brought closer to the tip of the dust lip portion 3b (see FIG. 1). 2), when gas is ejected from the open end, which is the tip of the groove 11a as a gas passage, as shown by an arrow a in FIG. 2, the gas appears between the pointed end of the dust lip portion 3b and the outer periphery of the piston rod 2. The gas is ejected into the empty space A, and as a result, the dust pressure portion 3b tends to expand from the inner peripheral side by the gas pressure in the empty space A.

The gas filling jig 10 of this embodiment
In order to insert the tip portion 11 between the inner periphery of the dust lip portion 3b of the oil seal 3 and the outer periphery of the piston rod 2, first, the insertion portion 11
b is inserted between the inner circumference of the dust lip portion 3b and the outer circumference of the piston rod 2.

As a result, in this type of conventionally proposed gas filling jig, when the tip is inserted between the inner circumference of the dust lip portion 3b and the outer circumference of the piston rod 2, Is in contact with the tip of the dust lip portion 3b over the entire circumference, so that a large contact resistance is generated. On the other hand, the tip of the insertion portion 11b is located at the inner circumference of the dust lip portion 3b. So-called only small contact resistance when it is inserted between the
This facilitates the insertion operation of the insertion section 11b.

Next, as shown in FIG. 1, the guide ring 20 has a main body 21 and an abutting portion 22. It is interposed so as to enable helical rotation and set to be fixed to the hydraulic shock absorber side.

To explain a little, first, as shown in FIG. 2, the main body 21 has a screw-shaped guide groove, that is, a screw 21a on its inner periphery.
0, a thread 11 formed on the outer periphery on the proximal side of the distal end portion 11
c (see FIG. 4) is screwed.

Next, the contact portion 22 is provided in a flange shape on the outer periphery of the lower end of the main body portion 21, and this is brought into contact with the bump plate 7 provided on the upper end portion 5 b of the packing case 5. By doing so, it moves with the movement of the main body 21,
That is, it is set so as to be prevented from rotating with the rotation of the distal end portion 11 and from moving up and down, in particular, descending as the distal end portion 11 descends.

Incidentally, the guide ring 20 will be provided in a state of being connected to the gas sealing jig 10 in many cases, but the point is that the spiral of the distal end portion 11 of the gas sealing jig 10 is important. As long as rotation can be realized, it is a matter of course that the rotation may be set separately from the gas sealing jig 10.

In filling the gas into the hydraulic shock absorber by the gas filling device according to the present embodiment formed as described above, as shown in FIG. The tip of the protruding insertion portion 11b is brought into contact with the pointed end of the dust lip portion 3b of the oil seal 3 slidingly contacting the outer periphery of the piston rod 2.

At this time, the guide ring 20 is maintained in a state in which the contact portion 22 is in contact with the bump plate 7 in a fixed state, and the movement thereof is prevented.

When the tip portion 11 is rotated from the above state, the tip of the insertion portion 11b enters a state between the pointed portion of the dust lip portion 3b and the outer periphery of the piston rod 2. Gas from the opening end of the groove 11a as a gas passage formed on the inner peripheral side of the recess 11b is jetted into the empty space A formed between the pointed end of the dust lip 3b and the outer periphery of the piston rod 2. As a result, the dust lip portion 3b expands, and the subsequent insertion portion 11b can be easily advanced.

The expansion of the dust lip portion 3b is continuously realized in the circumferential direction of the dust lip portion 3b by the insertion portion 11b spirally rotating around the outer periphery of the piston rod 2. As a result, the distal end portion 11 is screwed between the inner periphery of the dust lip portion 3b and the outer periphery of the piston rod 2 so that the distal end portion 11 continues to the insertion portion 11b.

At this time, as described above, since the dust lip portion 3b is maintained in the expanding tendency, the so-called unreasonable force is not applied to the tip end of the dust lip portion 3b when the distal end portion 11 is inserted. Therefore, a situation in which the tip portion is pushed into the inner peripheral side of the dust lip portion 3b together with the tip portion 11, that is, a situation in which the tip portion is entangled does not occur, and a phenomenon in which the tip portion of the dust lip portion 3b is damaged is not caused. Will be done.

In the above state, the tip 11
The gas through the groove 11a raises the oil lip portion 3c (see FIG. 2) of the oil seal 3, that is, the oil lip portion 3c tends to expand, so that the upper side of the bearing 8 (see FIG. 2), that is, the hydraulic buffer It will flow into the vessel.

After the filling of the predetermined gas is completed, the leading end 11 of the gas filling jig 10 is pulled out, whereby the interference of the oil seal 3 is restored and the tightening force of the garter spring 4 is applied. Therefore, the inner circumference of the dust lip portion 3b comes into sliding contact with the outer circumference of the piston rod 2 in a close state, and the gas is sealed in the hydraulic shock absorber.

Although not shown, when the gas is sealed by inserting the distal end 11 of the gas sealing jig 10 so-called deeply (see the phantom diagram in FIG. 6), the inside of the hydraulic shock absorber is left as it is. Of course, it is also possible to remove the gas in order to adjust the pressure of the gas sealed in the gas.

According to the above description, it is essential that the insertion portion 11b of the gas sealing jig 10 is formed so as to protrude from the distal end of the distal end portion 11. Groove 11a as a gas passage
Although not shown, instead of being formed on the inner surface of the insertion portion 11b as in the illustrated embodiment, even if it is formed on another location, that is, on the inner periphery of the distal end portion 11, In this case, in this case, the groove 11 is inserted into the insertion portion 11b.
Since a is not formed, it is advantageous in that the rigidity of the insertion portion 11b can be increased.

Further, the distal end portion 1 having the insertion portion 11b
1 may be maintained at the same level as the tip of the conventional gas filling jig of this type, but the insertion of the tip 11 following the insertion portion 11b is smoothly performed. As shown in FIG. 4, the insertion portion 11b is helically inclined from one side on the right side in the figure to the other side on the left side in the figure as shown in FIG. preferable.

When the tip of the distal end portion 11 is spirally inclined, the inclination starting from one side of the insertion portion 11b is changed as shown in a virtual diagram in FIG.
May be set so as to start from the tip of the tip. In this case, it is advantageous in that the insertion of the tip 11 following the insertion part 11b can be realized more smoothly.

Further, as described above, a plurality of grooves 11a as gas passages may be provided (FIG. 5).
In this case, although not shown, each groove 11a may be formed on the inner peripheral side of each of the plurality of insertion portions 11b, and in this case, the insertion portion 1
The plurality of 1b is advantageous in that the rotation angle of the distal end portion 11 can be reduced and a predetermined insertion state of the distal end portion 11 can be realized, and since a plurality of gas passages is provided, the This is also advantageous in that the injection time can be reduced.

As described above, the oil seal 3 is
It is assumed that this type of oil seal is configured in the same manner as a conventionally provided oil seal, but instead, as shown by a phantom diagram in FIG. 2, a gap between the dust lip portion 3b and the main body portion 3a is formed. In this case, the dust concentration portion 3b may be set to have the stress concentration concave portion 3d, and the dust lip portion 3b may be set to be a fulcrum so as to be easily bent, that is, to be easily expanded.

[0056]

As described above, according to the present invention, the distal end of the gas filling jig is inserted between the inner periphery of the dust lip portion of the oil seal and the outer periphery of the piston rod to thereby provide the hydraulic shock absorber. In filling a predetermined gas into the inside, it is assumed that the tip of the gas filling jig has an insertion portion protruding from the tip, so that the inner circumference of the dust lip and the outer circumference of the piston rod In comparison with the case where the tip is to be inserted simultaneously over the entire circumference,
It becomes possible to insert the insertion part easily, and
There is an advantage that the distal end portion can be inserted between the inner periphery of the dust lip portion and the outer periphery of the piston rod so as to follow the insertion portion.

According to the present invention, since the dust lip portion can be maintained in an expanding tendency by utilizing the gas pressure, the gas pressure can be used together with the insertion portion when the insertion portion is inserted. In this case, there is an advantage that the insertion of the insertion portion and the subsequent insertion of the distal end portion can be more easily realized.

Further, according to the present invention, since the distal end is inserted while being spirally rotated, the insertion operation can be performed in comparison with the case where the distal end is inserted straight along the axial direction of the piston rod. Of course, as described above, in conjunction with maintaining the dust lip portion in an expanding tendency by using gas pressure, as described above, it is not necessary to apply so-called unreasonable force to the tip portion of the dust lip portion, Therefore, a situation in which the tip is pushed into the inner peripheral side of the dust lip together with the tip of the gas sealing jig, that is, a situation in which the tip is entangled, does not occur, and the tip is not damaged. A predetermined gas can be sealed in the hydraulic shock absorber.

In the case where a plurality of grooves as gas passages are set and each groove is formed on the inner peripheral side of each of the plurality of insertion portions, the insertion portion Is a plurality of gas passages, which is advantageous in that the rotation angle of the front end portion can be reduced to realize a predetermined insertion state of the front end portion. This is also advantageous in that the injection time can be reduced.

Further, the oil seal has a stress concentration concave portion between the dust lip portion and the main body portion, and is set so that the dust lip portion is easily bent by using the stress concentration concave portion as a fulcrum. In this case, the dust lip portion can be more easily expanded.

As a result, according to the present invention, the distal end of the gas sealing jig is inserted between the inner periphery of the dust lip portion of the oil seal and the outer periphery of the piston rod with which the dust lip slides, and the gas is introduced into the hydraulic shock absorber. In this case, there is an advantage that it is optimal to allow a predetermined gas to be filled in the hydraulic shock absorber without lowering the sealing performance of the oil seal.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view showing a state in which a gas filling device according to an embodiment of the present invention is set in a hydraulic shock absorber.

FIG. 2 is an enlarged vertical sectional view showing a state in which a dust lip portion of an oil seal is expanded in diameter by a gas sealing jig constituting the gas sealing device of FIG.

FIG. 3 shows a state in which the tip of a gas filling jig constituting the gas filling device of FIG. 1 is inserted between the inner periphery of a dust lip portion of an oil seal and the outer periphery of a piston rod.
FIG.

FIG. 4 is a side view of the gas sealing jig with a tip portion partially cut away.

FIG. 5 is a cross-sectional view of a tip portion taken along line XX in FIG.

FIG. 6 is a longitudinal sectional view partially showing a state of use of a gas filling device as a conventional example.

FIG. 7 is an enlarged longitudinal sectional view showing an oil seal arranged in a conventional hydraulic shock absorber.

[Explanation of symbols]

 Reference Signs List 2 piston rod 3 oil seal 3a main body 3b dust lip 3d stress concentration recess 5 packing case 10 gas sealing jig 11 tip 11a groove as gas passage 11b insertion part 20 guide ring 21a screw forming screw guide groove Article

Claims (1)

[Claims] 1. A gas formed on an inner periphery of a tip portion of a gas sealing jig inserted between an inner periphery of a dust lip portion and an outer periphery of a piston rod in an oil seal housed on an inner peripheral side of a packing case. In a gas filling device for filling a predetermined gas into a hydraulic shock absorber through a passage, a guide ring having a screw-shaped guide groove on an inner periphery and being fixed to the hydraulic shock absorber side is provided. The distal end of the gas sealing jig is screwed into the threaded guide groove of the ring, and an insertion portion extending along the axial direction at the distal end of the distal end of the gas sealing jig is provided at the distal end of the distal end of the gas sealing jig. Gas filling device characterized by being formed so as to protrude