JPH1113816A - Gas sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To seal prescribed gas in a hydraulic shock absorber without decreasing seal performance in an oil seal, in the case of sealing gas in the hydraulic shock absorber by inserting a tip end part in 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 with which the internal periphery is brought into slide contact. SOLUTION: A device has an operating equipment 20 provided to appear in an internal peripheral side through a dust release hole 5d from a peripheral side of a packing case 5 with a tip end part 21 into contact with a dust lip part in an oil seal 3, and a gas sealing jig 10 sealing gas in a hydraulic shock absorber through a gas passage 11a formed in an internal periphery of a tip end part 11 inserted between an internal periphery of the dust lip part in the oil seal 3 and an external periphery of a piston rod 2. Here, by external force action under a condition of the operating equipment 20 allowing the tip end part 21 to abut to the dust lip part, it is set so that the dust lip part can be spread.

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. 8, the oil seal 3 has a structure having a dust lip portion 3b and an oil lip portion 3c integrally connected to a main body portion 3a having a cored bar 31. A dust lip portion 3b on the upper end side in the figure faces the outside of the cylinder 1 (not shown),
The oil lip 3c at the lower end in FIG.
It is said to face inside.

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 penetrate, and dust enters, it may be damaged by dust on the outer periphery of the piston rod 2 or oil leakage due to wear of the oil lip portion 3a due to the damage on the piston rod 2. 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 gas between an inner periphery of a dust lip portion of an oil seal and an outer periphery of a piston rod with which the dust lip slides. When gas is sealed in the hydraulic shock absorber by inserting the tip of the sealing jig, it is possible to seal a predetermined gas into the hydraulic shock absorber without lowering the sealing performance of the oil seal. It is an object of the present invention to provide a gas filling device which is optimal for the above.

[0013]

In order to achieve the above-mentioned object, the configuration of the gas filling device according to the present invention is basically changed from the outer peripheral side of the packing case to the packing case through a dust discharge hole formed in the packing case. An operating tool which is located on the inner peripheral side of the packing case and whose leading end abuts on a dust lip portion of the oil seal housed on the inner peripheral side of the packing case;
A gas filling jig for filling gas into the hydraulic shock absorber through a gas passage formed in an inner periphery of a tip portion inserted between an inner periphery of a dust lip portion and an outer periphery of a piston rod in the oil seal. In this case, it is assumed that the operating tool is set so as to be able to expand the dust lip portion by an external force under a state where the operating tool is in contact with the tip portion.

[0014] More specifically, the operating tool is held, for example, so that the base end thereof can be moved along an axial direction of the piston rod by an appropriate guide tool. It is assumed that the tip is set so as to move in parallel according to.

Further, in the oil seal, a stress concentration recess is formed between the dust lip portion and the main body portion connecting the dust lip portion, and the dust lip portion is opened when the dust lip portion is opened by the operating tool. It is preferable that the section is set so as to be easily expanded.

Therefore, in a gas filling jig under the condition that the dust lip portion of the oil seal is expanded by the action of an external force via the operating tool, the tip portion of the oil sealing jig is crushed while ejecting gas. Part can be approached,
At this time, the dust lip portion is further expanded due to the pressure of the gas ejected from the gas sealing jig.

[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 And a packing case 5 for accommodating the oil seal 3 slidably in contact with the outer periphery of the piston rod 2 from the outer peripheral side. A reservoir chamber (not shown) having a gas chamber portion R is formed between the outer casing 6 and the outer casing 6 disposed on the outer peripheral side of the casing 1, and the lower end 5 a of the packing case 5 is opened at the opening end 6 a of the outer casing 6. It is used when gas is sealed in a hydraulic shock absorber that is inserted in a press-fit state on the inner peripheral side of the device and sealed by welding or the like.

Here, a little explanation will be given in relation to the hydraulic shock absorber. First, as shown in FIG. 2, the oil seal 3 is basically formed in the same manner as in the conventional example (see FIG. 8). The dust lip 3b and the oil lip 3c are provided integrally with the main body 3a having the metal core 31, and the dust lip 3b on the upper end side in FIG. It is assumed that the oil lip 3c, which is the lower end in FIG.

The dust lip portion 3b and the oil lip portion 3c are set so as to have a predetermined interference. However, the tightening force by the respective garter springs 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.

However, in the illustrated embodiment, a stress concentration concave portion 3d is provided between the dust lip portion 3b and the main body portion 3a, and the stress concentration concave portion 3d is used as a fulcrum. Are set to be easily bent, that is, the dust lip portion 3b is easily expanded.

Therefore, instead of the embodiment shown in FIG. 2, this stress concentration concave portion 3d is formed on the so-called inner periphery, for example, as in the embodiment shown in FIG. 3, and the embodiment shown in FIG. As in the embodiment shown in the so-called inner and outer peripheries, as shown in the solid line diagram in FIG. 5, a plurality of them are formed in the so-called inner periphery, or in the embodiment shown in the virtual diagram in FIG. As described above, a plurality of inner and outer peripheral portions may be formed.

Further, in the illustrated embodiment, it is assumed that the cross-sectional shape of the stress concentration concave portion 3d is set to a U-shape, but instead of this, it is set to a V-shape, not shown. It may be.

Next, the packing case 5 has an upper end 5b.
And a bump insertion plate 5c formed in the center with the bump plate 7.
The piston rod 2 is inserted through 7a.

Incidentally, when the gas filling jig 10 is set in the hydraulic shock absorber, the distal end portion 11 is inserted through the rod insertion holes 5c and 7a in a state where the distal end portion 11 is interposed on the outer periphery of the piston rod 2.

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, a space between the cylinder 1 and the outer cylinder 6 is set as a reservoir chamber having a 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.

As shown in FIG. 6, the gas sealing jig 10 is provided with a dust lip portion 3b of the oil seal 3.
The gas is sealed in the hydraulic shock absorber with the tip 11 inserted between the inner circumference of the piston rod 2 and the outer circumference of the piston rod 2. It is configured as disclosed in Japanese Patent No. 16859.

That is, the gas sealing jig 10 has a tip 1 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.
1, a groove 11a as a gas passage is formed in the inner periphery of the tip portion 11.
Is connected to a gas supply / discharge source (not shown) connected to the gas sealing jig 10 outside.

And, in this gas filling jig 10,
As shown in FIG. 2, the tip of the tip portion 11 is set to a curved end having a radius of an appropriate dimension so that the tip portion of the dust lip portion 3 b in the oil seal 3 is slidably contacted. Groove 11a so as to follow
Is set so that the open end thereof faces the outer periphery of the piston rod 2.

Therefore, at the tip 11 of the gas sealing jig 10, when the tip is approached to the tip of the dust lip 3b while ejecting gas from the open end (see FIG. 1). 2), as indicated by an arrow a in FIG. 2, the gas is ejected into a space A that appears between the pointed portion of the dust lip portion 3b and the outer periphery of the piston rod 2. As a result, The dust pressure portion 3b is urged to expand from the inner peripheral side by the gas pressure in the empty space A.

It is to be noted that the above-mentioned front end portion 11 is
Is pulled out from the inner peripheral side of the dust lip portion 3b, the interference in the oil seal 3 is restored and the inner circumference of the dust lip portion 3b is in close contact with the outer periphery of the piston rod 2 due to the tightening force of the garter spring 4. Of course, it will come into sliding contact with.

On the other hand, as shown in FIG.
The oil seal 3 is provided on the inner peripheral side of the packing case 5 from the outer peripheral side of the packing case 5 to the inner peripheral side of the packing case 5 through a dust discharge hole 5 d formed in the packing case 5. Is set so as to contact the dust lip portion 3b.

The operation tool 20 is held by a suitable guide tool G such that the base end portion 22 can move along the axial direction of the piston rod 2 which is vertically in the figure. The tip 21 is set to move in parallel with the lowering of the end 22.

Incidentally, the above-mentioned guide member G may be arbitrarily set with respect to its overall configuration, but in many cases,
Although not shown, it may be configured as a part of the gas sealing jig 10 described above.

Therefore, in this operating tool 20, it is needless to say that the above-mentioned guide tool G is required, but the dust release which is almost always opened in the packing case 5 in this type of hydraulic shock absorber. Since it is sufficient to use the hole 5d, no particular design change or the like is required for the hydraulic shock absorber itself.

In filling the gas into the hydraulic shock absorber with the gas filling device according to this embodiment formed as described above, as shown in FIG. The tip is brought into contact with the tip of the dust lip portion 3b of the oil seal 3 which is in sliding contact with the outer periphery of the piston rod 2.

On the other hand, the distal end portion 21 of the operating tool 10 is brought into contact with the dust lip portion 3b of the oil seal 3 (FIG. 2).
With the external force acting on the base end portion 22 (see FIG. 1), the distal end portion 21 is lowered along the axial direction of the piston rod 2 (see the solid line diagram in FIG. 2).

As a result, the dust lip portion 3b slightly bends, that is, expands, so that the inner circumference thereof, that is, the portion slidingly contacting the outer circumference of the piston rod 2 is used as a fulcrum.

At this time, in the oil seal 3, the stress concentration concave portion 3 is located between the dust lip portion 3b and the main body portion 3a.
d, and the dust concentration portion 3b is set as a fulcrum so that the dust lip portion 3b is easily bent, so that the above-described dust rup portion 3b can be easily expanded. Will be.

Further, in the gas filling jig 10, a front end portion 11 which is in contact with a sharp end portion of the dust lip portion 3b is provided.
Gas is ejected from the tip of the piston rod 2 toward the outer peripheral side of the piston rod 2, and this gas, that is, the gas pressure, appears between the tip of the dust lip portion 3 b and the outer periphery of the piston rod 2. The dust lip portion 3b is expanded from the inner peripheral side to the space A, and the expanded state of the dust lip portion 3b tends to increase.

When lowering the distal end 11 of the gas sealing jig 10 from the above state, as shown in FIG. 6, the distal end 11 is positioned between the inner circumference of the dust lip 3b and the outer circumference of the piston rod 2. Will be present in between.

At this time, since the dust lip portion 3b is maintained in the tendency to expand, the so-called excessive force is not applied to the tip portion of the dust lip portion 3b when the distal end portion 11 is inserted. A situation where the portion is pushed into the inner peripheral side of the dust lip portion 3b together with the distal end portion 11, that is, a situation in which the portion is entangled does not occur, so that it is not necessary to cause a phenomenon that the tip portion of the dust lip portion 3b is damaged. .

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 so-called deep insertion of the tip 11 of the gas sealing jig 10 (see a phantom diagram in FIG. 7), 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.

In the above embodiment, the oil seal 3
Has a stress concentration concave portion 3d between the dust lip portion 3b and the main body portion 3a. However, from the intention of the present invention, the arrangement of the stress concentration concave portion 3d may be omitted. In this case, the expandability of the dust lip portion 3b is slightly inferior, but there is an advantage that a design change in the oil seal 3 is not required, and a predetermined interference in the dust lip portion 3b can be ensured. This is advantageous.

[0048]

As described above, 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 to thereby provide the hydraulic shock absorber. When the predetermined gas is sealed in the inside, the dust lip portion can be maintained in a tendency to expand by the use of the external force by the operating tool and the gas pressure from the gas sealing jig. It is not necessary to apply so-called excessive force. Therefore, a situation in which the tip portion is pushed into the inner peripheral side of the dust lip portion together with the tip portion of the gas filling jig, that is, a situation in which the tip portion is caught is not exhibited, and the tip portion is not damaged. The predetermined gas can be sealed in the hydraulic shock absorber without causing the sticking phenomenon.

Then, the operating tool holds the base end by an appropriate guide tool so as to be movable along the axial direction of the piston rod, and moves the front end in parallel with the lowering of the base end. If it is set, it is easy to lower the tip of the operating tool so as to expand the dust lip, but this tip is opened from the outer periphery of the packing case to the packing case. Since it is sufficient to be present on the inner peripheral side of the packing case through the dust release hole of the drilling, in consideration of the fact that this dust release hole is opened in most cases in the packing case in this type of hydraulic shock absorber, Therefore, the hydraulic shock absorber itself does not require any special design change or the like.

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 easily expanded.

As a result, according to the present invention, the tip 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, so that 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 an operation tool constituting the gas sealing device of FIG. 1;

FIG. 3 is a partial cross-sectional view showing an embodiment in which a position where a stress concentration concave portion is provided in an oil seal is changed.

FIG. 4 is a partial cross-sectional view showing another embodiment in which a position where a stress concentration concave portion is provided in an oil seal is changed.

FIG. 5 is a partial cross-sectional view showing still another embodiment in which a position where a stress concentration concave portion is provided in an oil seal is changed.

6 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 the dust lip portion of the oil seal and the outer periphery of the piston rod.
FIG.

FIG. 7 is a longitudinal sectional view partially showing a usage state of a gas filling device as a conventional example.

FIG. 8 is an enlarged longitudinal sectional view showing an oil seal provided in a conventional hydraulic shock absorber.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston rod 3 Oil seal 3a Main part 3b Dust lip part 5 Packing case 5d Dust discharge hole 10 Gas filling jig 11, 21 Tip 11a Groove as gas passage 20 Operating tool 22 Base end G Guide tool

Claims (1)

[Claims] 1. A dust lip portion of an oil seal which is located on the inner peripheral side of the packing case from the outer peripheral side of the packing case to the inner peripheral side of the packing case via a dust discharge hole formed in the packing case and is provided on the inner peripheral side of the packing case. The gas in the hydraulic shock absorber through a gas passage formed in the inner periphery of the tip portion inserted between the inner periphery of the dust lip portion and the outer periphery of the piston rod in the oil seal and the operating tool with which the portion contacts. And a gas sealing jig for enclosing the dust lip, and the operating tool is set so as to be able to expand the dust lip by an external force under a state in which the tip is in contact with the dust lip. Characteristic gas filling device