JPS6332431Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shock absorber suitable for use in front forks of motorcycles, etc.

In this type of conventional front fork, an inner tube is slidably inserted into an outer tube via a piston, an oil seal is built into the upper inside of the outer tube, and a dust seal is fitted to the upper end of the outer tube. Together, these oil seals and dust seals come into sliding contact with the inner tube, thereby sealing the space between the outer tube and the inner tube.

However, when the inner tube slides, the lips of the oil seal and the dust seal come into sliding contact with the outer periphery of the inner tube, resulting in scratches on the outer surface of the inner tube, and there is a problem in that the sealed oil leaks from the scratches. Furthermore, when the oil seal makes sliding contact with the inner tube, sliding resistance is generated due to the friction of the oil seal, which impairs smooth operation and makes the riding comfort of motorcycles, etc. worse. Furthermore, air accumulates in the lower part of the oil seal during use, and since this air cannot escape, lubricating oil does not circulate sufficiently around the oil seal, causing poor sliding movement of the inner tube and causing seizure.

Therefore, the purpose of the present invention is to reduce the friction on the inner tube and prevent oil leakage.
Another object of the present invention is to provide a shock absorber for use in a front fork of a motorcycle, etc., which has good circulation of lubricating oil and smooth operation.

In order to achieve this objective, the present invention interposes a sealing member such as a diaphragm between the upper part of the outer tube and the outer surface of the inner tube, guides the outer periphery of the sealing member with a cover, and connects the end of the cover and the inner tube. The feature is that the space between the shoes is covered with a stretchable boot.

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

FIG. 1 shows a shock absorber according to a preferred embodiment of the present invention, in which a sleeve 22 and a cover 27 are provided between an outer tube 1 and an inner tube 2.
It is sealed by intervening.

An inner tube 2 is slidably inserted into the outer tube 1 via a piston 5, and a hollow cylinder 6 is inserted from the center of the lower end of the outer tube 1.
stands up, and the outer periphery of the upper end of the hollow cylinder 6 is in sliding contact with the inside of the inner tube 2 via the piston.

Two upper and lower oil chambers 7 are defined within the outer tube 1 and the inner tube 2 via the piston 5, and an oil chamber 8 that communicates with each other is defined within the hollow cylinder 6 and the inner tube 2. A gas chamber 9 is defined in the upper part of the chamber.

Built into the piston 5 is a passage that communicates the upper and lower oil chambers 7, and a valve that opens and closes this passage to generate damping force.

A spring is interposed in the upper part of the piston 5, so that the cushion becomes effective when the piston is fully extended.

The hollow cylinder 6 is provided with an orifice 10 that allows the oil chambers 7 and 8 to communicate with each other, and an oil hole rod 11 is provided at the lower part of the outer periphery of the hollow cylinder 6.
and piston 5 to make the cushion effective at maximum compression.

A spring seat 12 is provided inside the upper part of the inner tube 2 so as to be movable up and down, and a suspension spring 13 is interposed between the spring seat 12 and the upper end of the hollow cylinder 6, and the spring 13 always attaches the inner tube 2 in the extension direction. It is strong.

A cap 14 is screwed onto the upper end of the inner tube 2 so as to be movable up and down, and as the cap 14 moves, a driving member 15 in contact with the cap changes the position of the spring seat 12, thereby causing the initial spring load of the spring 13. can be adjusted. The inner tube 2 is connected to, for example, a motorcycle via an upper bracket 16 and an under bracket 17.

The outer tube 1 has a bracket 18 for mounting the axle and a bracket 1 for mounting the caliper.
9 and a bracket 20 for fender attachment are fixed.

A spacer 21 is placed on the upper outer periphery of the inner tube 2.
The spacer 21 has an unevenness formed on its lower outer periphery, and one end of the sleeve 22 is airtightly fitted into the unevenness, and the sleeve 22 is fixed via a fastener such as a ring 23. On the other hand, a pipe-shaped joint 24 is screwed into the upper part of the outer tube 1, and the other end of the sleeve 22 is hermetically fitted into a recess provided in the upper part of the joint 24, thereby connecting the inner tube 2 and the sleeve 22. An oil chamber 25 is defined between the outer tube 1 and the sliding surfaces of the inner tube 2 and the outer tube 1 are sealed.

One or more through holes a, b, c...n are formed in the inner tube 2, and the through holes a, b,
The oil chamber 25 is connected to the inner tube 2 via c...n.
The hydraulic oil supplied to the oil chamber 9 is also used as lubricating oil when the inner tube 2 is sliding. Seals such as O-rings are interposed between the spacer 21 and the inner tube 2 and between the joint 24 and the outer tube 1.

A rotation stopper ring 26 of different diameters is connected to the lower outer periphery of the spacer 21, as shown in FIG. A cover 27 is disposed around the outer periphery of the sleeve 22, and the sleeve 22 and the cover 27 are fixed to the joint 24 by caulking the lower end of the cover 27. A hole is provided at the upper end of the cover 27, and the cover 27 is fixed to the joint 24 by caulking the lower end of the cover 27. is fitted onto the outer circumferential protrusion 26' of the rotation stopper ring 26 and held therein. A plurality of two rows of holes 28 are spaced apart in the circumferential direction within the rotation stop ring 26.

A snake-shaped boot 29 is attached to the outer periphery of the spacer 21.
The lower part of the boot 29 is fitted into the rotation stopper ring 26 while enclosing the upper end of the cover 27, and the upper end of the boot 29 is fitted into the upper part of the spacer 21 through a hole, a protrusion, etc. There is.

An air chamber 30 is defined within the boot 29, and this air chamber 30 communicates with an air chamber 31 defined above the sleeve 22 through a hole 28 in the rotation stopper ring 26, and through a hole provided in the upper part of the boot 29. It communicates with the outside air.

Since the cover 27 is connected to the rotation stop ring 26, and the rotation stop ring 26 is connected to the spacer 21 with different diameters, the sleeve 22 will not twist even if the outer tube 1 is rotated when installing or removing it from the vehicle body. Boots 29 also cover 27 and spacer 2
1, it does not twist and is easy to handle.

By providing the hole 28 in the rotation stopper ring 26, the clearance between the inner tube 2 and the outer tube 1 and the lateral load due to the deflection of the inner tube 2 are reduced, and the rotation stopper is prevented and the mounting part of the cover 27 and the joint 24 is reduced. Preventing damage.

If the stroke is short and the rigidity of the sleeve 22 allows the spacer 21 to rotate by overcoming the friction of the O-ring on the inner circumference, the rotation stop ring 26 is not necessarily required.

By fixing the lower end of the spacer 21 to the inner tube 2 via a snap spring, positioning during assembly is possible and it is possible to prevent the oil chamber 25 from being sucked in when it becomes negative pressure.

Regarding the operation, when compression is performed from the fully extended state, the air or hydraulic oil in the oil chamber 25 is pushed out to the oil chamber 8 or the gas chamber 9,
At this time, the volume of the chamber 31 expands, but since the boot 29 shrinks, it is difficult to supply air to the chamber 31.
The difference between the expansion of the chamber 31 and the volume reduction in the boot 29 is supplied and discharged from the upper hole of the boot 29.
However, if this difference is made to a level that does not interfere with the function of the boot 29, the hole is not necessary.

In the above embodiment, since the inner tube 2 and the outer tube 1 are airtightly connected via the sleeve 22, a complete sealing effect can be achieved, the inner tube 2 is not damaged when sliding, and the inside of the sleeve 22 is not damaged. The hydraulic oil acts as a lubricating oil. Furthermore, since the cover 27 is disposed around the outer periphery of the sleeve 22 and the boot 29 covers the space between the upper end of the cover 27 and the upper part of the spacer 21, sand and mud from the outside are prevented from directly jumping into the rolling surface of the sleeve 22. By setting the difference between the expansion of the chamber 31 and the volume reduction inside the boot 29 small as described above, the boot 29
This reduces the amount of air that enters and exits from the outside through the holes 29a, and prevents sand, mud, etc. from entering the rolling surface of the sleeve 22 along with the air.
It is possible to measure the improvement of durability.

FIG. 4 shows another embodiment of the present invention, which eliminates the use of spacers and changes the method of fixing the sleeve. That is, the upper end of the sleeve 22 is fixed to the inner tube 2 via the ring 23,
The other end of the sleeve 22 is caulked and fixed to a joint 24 that is press-fitted into the outer tube 1 side through a seal, and this joint 24 is attached to the ring nut 3.
It is detachably fixed to the outer tube 1 side via 2.

A cutout 33 is formed in the outer circumference of the inner tube 2 in the longitudinal direction, and the rotation stopper ring 26 is deformed and connected to the inner tube 1 through the cutout 33 to have different diameters. A cover 27 and a boot 29 are held on the rotation stopper ring 26 as in FIG. 1.

The upper end of the boot 29 is fixed to the outer periphery of the inner tube 2 via a stopper member 33 such as a ring, and a hole 29a is bored in the upper part of the boot 29 as in FIG. 1.

Since the action and effect are the same as in the case of FIG. 1, their explanation will be omitted.

As described above, the present invention uses a sleeve to airtightly connect the inner tube and outer tube in place of the conventional oil seal and dust seal.
Problems such as vertical scratches on the inner tube and oil leaking from there are resolved, and stable sealing is achieved. Hydraulic oil is supplied and discharged within the sleeve, resulting in good lubrication and less friction. It operates smoothly and improves the riding comfort of the motorcycle when used on a motorcycle, etc. The structure of the sealing member such as the sleeve is simple and easy to install, so the shock absorber itself is easy to assemble and costs can be reduced. , processing accuracy may be relatively rough compared to oil seals, etc.;
The outer circumference of the sleeve is guided by a cover provided on the outer tube side, and a retractable boot is placed between the end of the cover and the inner tube side.
This has the effect of preventing sand, mud, etc. from entering the rolling surface of the sleeve, thereby improving the durability of the sleeve.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view of a shock absorber according to an embodiment of the present invention, and FIG. 2 is a line A-A in FIG. 1.
FIG. 3 is a partially enlarged longitudinal sectional front view of FIG. 1, and FIG. 4 is a partially longitudinal sectional front view of a shock absorber according to another embodiment. 1... Outer tube, 2... Inner tube, 8... Oil chamber, 22... Sleeve, 23...
Ring, 24...Joint, 25...Oil chamber, 3
2...Ring nut, a, b, c...n...through hole.

Claims (1)

[Claims for Utility Model Registration] (1) An inner tube is slidably inserted into an outer tube, a sleeve is hermetically connected between the outer circumference of the inner tube and the upper part of the outer tube, and the outer circumference of the sleeve is provided on the outer tube side. A shock absorber that is guided by a cover with a flexible boot and a retractable boot between the end of the cover and the inner tube side. (2) The shock absorber according to claim 1, wherein the oil chamber formed in the sleeve communicates with the oil chamber in the inner tube through a through hole provided in the inner tube. (3) The shock absorber according to claim 1, wherein one end of the sleeve is fixed to the inner tube side with a ring, and the other end is caulked to a joint provided on the outer tube. (4) The shock absorber according to claim 3 of the utility model registration, wherein the joint is held in the outer tube by a ring nut.