JPH0228285Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention is a gas-filled hydraulic shock absorber that is equipped with a dust cover to prevent dust, water, etc. from entering the gas-filled passageway from the outside. , relates to a hydraulic shock absorber with improved dust sealing properties.

(Prior art) A type of hydraulic shock absorber in which gas is sealed through a gas filling passage composed of an outer circumferential groove of an oil seal and a tube that forms the outer shell of the hydraulic shock absorber and covers the outer circumferential groove is disclosed, for example, in Japanese Utility Model Publication No. 47-3211. It has been known for a long time.

In this hydraulic shock absorber, gas can be prevented from escaping by a tongue protruding from the oil seal in the middle of the gas filling passage, which extends toward the tube and toward the side where pressure is applied. However, since the area from this tongue piece to the passage entrance is exposed to the outside, dust, water, etc. can easily enter from the outside, and when the tongue piece is pushed by dust etc., the sealed gas can be released. There was a fear that it might leak.

(Purpose of the invention) The present invention is intended to solve the above problem, and aims to provide a gas-filled hydraulic shock absorber that prevents dust, water, etc. from entering the gas-filled passage.

(Structure of the invention) In order to achieve the above object, the gas-filled hydraulic shock absorber of the present invention is a gas-filled hydraulic shock absorber in which gas is filled through a gas filling passage, and the inner periphery of the rod guide is guided by the rod guide. An oil seal is provided, the outer periphery of which is in pressure contact with the piston rod that is in pressure contact with the outer shell of the shock absorber, an outer flat portion is provided at a portion of the oil seal that is exposed from the end of the outer shell, and the outer peripheral side of the outer flat portion and the oil seal are A gas-filled passage communicating between the outside and the inside of the outer shell is provided by forming an outer circumferential groove on the outer circumferential surface of the oil seal. a dust cover that forms an annular tongue that seals the flow, is attached to the end of the outer shell, and presses against the inner peripheral side of the outer flat part of the oil seal to close the inlet of the gas filling passage; It is characterized by having the following.

The dust cover has a hole in the ceiling for the insertion of the piston rod, and includes a cap body attached to the end of the tube that forms the outer shell of the shock absorber, and a cap body that is provided on the ceiling of the cap body. An annular seal member may be provided on the end portion of the oil seal, which presses against the inner circumferential side of the outer flat portion of the oil seal to close the entrance of the gas filling passage when the cap member is attached to the end portion. A cap body is attached to the end of the tube forming the outer shell of the vessel, and the cap body is protruded inwardly and is attached to a ceiling portion having a hole for passing a piston rod formed in the cap body. An annular protrusion may be provided that presses against the inner peripheral side of the outer flat portion of the oil seal and closes the entrance portion of the gas filling passage when the oil seal is closed.

With this configuration, it is possible to reliably prevent dust, water, etc. from entering the gas-filled passage.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2 showing the first embodiment of the hydraulic shock absorber of the present invention, 1 is a tube forming the outer shell of the shock absorber, 2 is a piston slidably inserted into the tube 1, and 3 is a piston rod. , 4 is a mounting eye provided at the upper end of the piston rod 3, 5 is a mounting eye provided at the lower end of the tube 1, 6 is an annular rod guide, and 7 is an annular oil seal made of an elastic material with a reinforcing body 8 embedded therein. It is.

Reference numeral 9 denotes a dust cover that presses against the upper part of the oil seal 7 and closes the entrance of a gas filling passage 10, which will be described later. This dust cover 9 is attached to the tube 1 after gas is filled in the tube 1.
Hat-shaped cap body 1 attached to the upper end of tube 1
1, and a seal body 12 which is attached to the ceiling of the cap body 11 and has its lower end in pressure contact with the outer flat part of the oil seal 7 to close off the gas filling passage 10. A hole 11a for inserting the piston rod 3 is formed in the ceiling portion of the cap body 11, and the seal body 12 is bonded by fitting the annular stepped portion 12a into the hole 11a of the cap body 11. This seal body 12 is made of an elastic material such as rubber or synthetic resin.

The gas filling passage 10 includes an outer circumferential groove 7a formed in the oil seal 7 in the axial direction, a groove 6a formed in the outer circumference of the rod guide 6 that extends into the tube 1, and these grooves 6a, 7a.
The inner surface of the tube 1 covers the open side of the tube. The gas filling passage 10 is formed by an annular tongue piece 7 which is provided on the outer periphery of the oil seal 7 and extends toward the tube 1 and toward the side where pressure is applied.
b allows communication between the upstream side and the downstream side when gas is filled.

In order to fill the tube 1 of such a gas-filled hydraulic shock absorber with gas, the entire oil seal 7 is set in a gas filling device (not shown) without installing the dust cover 9, and the gas is introduced. The outer circumferential annular tongue piece 7 passes through the outer circumferential groove 7a of the oil seal 7.
b is bent in the inflow direction, and further flows into the tube 1 through the outer circumferential groove 6a of the rod guide 6. After filling the tube with gas, the tongue piece 7b comes into pressure contact with the inner surface of the tube 1 due to the pressure of the filled gas, thereby creating a gas seal.

Thereafter, the cap body 11 of the dust cover 9 is attached by press-fitting it to the end of the tube 1, and the lower end of the seal body 12 is brought into pressure contact with the outer flat part of the oil seal 7, so that the inlet of the gas filling passage 10 is closed to the outside. and completely cut it off.

This can prevent dust, water, etc. from entering the gas-filled passage 10 from the outside. Note that the dust cover 9 has the advantage that it can also be used as a bump rubber receiver. In addition, even if the tongue piece 7b is damaged, the entrance of the gas filling passage 10 is closed by the pressure contact between the seal body 12 and the elastic material portion of the oil seal 7, so that gas leakage can be completely prevented. can be achieved.

Figures 3 and 4 show a second embodiment of the hydraulic shock absorber of the present invention.
A dust cover 9' different from the dust cover 9 shown in FIGS. 1 and 2 is attached, and the other configurations are similar to those shown in FIGS. 1 and 2.

The dust cover 9' of this example has an annular inward protrusion 14 integrally formed on the central hole 13a side of a cap-shaped cap 13 that is attached to the end of the tube 1. The oil seal 7 is brought into pressure contact with the outer flat part of the oil seal 7 so that the entrance of the gas filling passage 10 can be closed.

Therefore, in this second embodiment, the dust cover 9'
can be directly manufactured by processing and forming from a metal plate, and only needs to be brought into pressure contact with the elastic outer flat part of the oil seal 7.
It has the advantage that it is easy to manufacture since there is no process of manufacturing and attaching the seal body 12 separately as in the case of the dust cover 9 of the embodiment.

(Effects of the invention) As explained above, according to the invention, the inlet of the gas-filled passage in a gas-filled hydraulic shock absorber is completely closed off from the dust cover. It is possible to completely prevent a situation where dust, water, etc. enter the gas seal and cause a gas leak. Furthermore, the present invention has the advantage of significantly increasing the reliability of use of the hydraulic shock absorber itself by eliminating failures due to gas leaks.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the first embodiment of the present invention, FIG. 2 is a sectional view showing the main parts of the device shown in FIG. This figure is a cross-sectional view showing the main part of the one shown in FIG. 3. 1...Tube (outer shell), 3...Piston rod, 6...Rod guide, 7...Oil seal,
7a...Oil seal outer circumferential groove, 7b...tongue,
9, 9'... Dust cover, 10... Gas filling passage, 11, 13... Cap body, 11a... Center hole in the ceiling of the cap body, 12... Seal body, 1
4...Introverted process.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In a gas-filled hydraulic shock absorber in which gas is filled through a gas-filling passage, the inner periphery is in pressure contact with the piston rod guided by the rod guide on the outside of the rod guide, and the outer periphery is in contact with the outer shell of the shock absorber. An oil seal that comes into pressure contact is provided, an outer flat portion is provided in a portion of the oil seal exposed from the end of the outer shell, and an outer circumferential groove is formed on the outer circumferential side of the outer flat portion and on the outer circumferential surface of the oil seal to connect the outside and the outer shell. a gas-filled passage communicating with the inside of the oil seal, and an annular tongue piece formed on the outer peripheral surface of the oil seal that allows gas to flow from the outside to the inside of the outer shell through the gas-filled passage, but blocks the opposite flow; The gas-filled hydraulic system is characterized by being provided with a dust cover that is attached to the end of the outer shell and presses against the inner peripheral side of the outer flat part of the oil seal to close the entrance of the gas-filled passage. buffer. (2) the dust cover is provided on a cap body which has a hole in the ceiling for the insertion of a piston rod and is attached to an end of a tube forming the outer shell of the shock absorber, and on the ceiling of the cap body; It is characterized by comprising an annular seal body that presses against the inner peripheral side of the outer flat part of the oil seal to close the entrance of the gas filling passage when the cap body is attached to the end of the tube. A gas-filled hydraulic shock absorber according to claim 1 of the utility model registration claim. (3) The dust cover is a cap body attached to an end of a tube forming the outer shell of the shock absorber,
The cap body protrudes inward from a ceiling portion having a hole for the piston rod insertion formed in the cap body, and when the cap body is attached, it comes into pressure contact with the inner peripheral side of the outer flat part of the oil seal and gas A gas-filled hydraulic shock absorber according to claim 1, characterized in that the gas-filled hydraulic shock absorber is provided with an annular protrusion that closes an entrance portion of a sealed passage.