JP2002005223A - Front fork for two-wheeler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove rider's displeasing feeling by cutting off the shock and its associated transmission of a resonant sound when a front fork strikes a bottom, and to prevent the contamination of a hydraulic fluid caused by genera tion of worn metal powder. SOLUTION: This front fork for two-wheeler is used to attenuate a shock when a cushion member 16 is forced to strike the bottom by interposingly equipping the cushion 16 absorbing the generated shock by accompanying with a collision of an inner tube 4 between a spacer 15 supporting the upper end of a suspension spring 12 with which the upper end of an inner tube is collided when the front fork 1 is forced to strike the bottom and an upper cap 7 used to close the upper end of an outer tube 3, and used to prevent a hydraulic oil from the contamination by preventing the worn metal powder generated by rubbing the metal upper cap 7 and the spacer 15 each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impact generated when a front fork performs a bottom compression operation when the front fork performs a maximum compression operation, in particular, an impact generated when the front fork hits the ground after a jump of a motorcycle such as a motocross race. However, the present invention relates to a front fork for a motorcycle having an impact absorbing mechanism for preventing the rider from transmitting the discomfort to the rider through the steering wheel.

[0002]

2. Description of the Related Art In a general motorcycle front fork, to reduce an impact input transmitted from a traveling road surface to a vehicle body through a front wheel, a front fork 1c shown in FIG. A telescopic tube 2 having a double-tube structure composed of an outer tube 3 and an inner tube 4 inserted into the tube (only one telescopic tube 2 arranged in parallel is shown in the figure).

[0003] A suspension spring 12 (shown as a coil spring, or a combination of a coil spring and an air spring or only an air spring) is provided between the upper cap 7 of the outer tube 3 and the damper mechanism 5 provided on the inner tube 4 side. In some cases, the shock input transmitted to the vehicle body is absorbed by the spring load of the suspension spring 12 and the damping force generated by the damper mechanism 5 described above.

Further, in this case, especially when the above-mentioned front fork 1c is used for a motorcycle for motocross racing, the front fork 1c has a large protruding bottom against the front fork 1c upon landing after jumping. Frequently, a shock input is applied.

Therefore, in this case, in addition to the above, a spring guide 11 interposed between the damper mechanism 5 and the upper cap 7 of the outer tube 3 is additionally provided.
Thereby, while compressing the cushion rubber 9 fitted to the upper cap 7 through the washer 10,
The upper end of the inner tube 4 abuts against the upper end flange of the spacer 15 so as to be mechanically suppressed by the upper cap 7.

[0006]

However, in the conventional front fork 1c configured as described above, the impact generated inside the front fork 1c is applied from the spacer 15 to the outer tube 3 through the upper cap 7. As a result, when the inner tube 4 abuts against the spacer 15 when the bottom hits the spacer 15, the inner tube 4 hits the spacer 15 violently, and the impact at that time is a bracket member (not shown) which is a mounting member from the outer tube 3 to the vehicle body. Through to the steering wheel, causing discomfort to the rider.

Further, vibration generated when the upper end of the inner tube 4 hits the spacer 15 when the front fork 1c strikes the bottom is transmitted through the upper cap 7 to the outer tube 3.
And resonated in the internal space of the front fork 1c to produce a loud sound, and this resonant sound also gave a rider a feeling of discomfort.

In addition, even during normal running, the spacer 15 is rubbed against the upper cap 7 of the outer tube 3 by the spring force of the suspension spring 12, and the upper cap of the outer tube 3 7
Since both the upper cap 7 and the spacer 15 are made of metal and are in direct contact with each other, the upper cap 7 and the spacer 15 are worn, and the metal powder is mixed in the working oil, and the front fork 1c is operated. It can also hurt.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to reliably cut off transmission of an impact generated when a front fork strikes the bottom and a resonance sound associated therewith, thereby preventing a rider from feeling uncomfortable. In addition, an object of the present invention is to provide a front fork for a motorcycle including a novel shock absorbing mechanism capable of preventing working oil from being contaminated by wear metal powder.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to close the upper end of the outer tube and the spacer for supporting the upper end of the suspension spring, which is an abutment member against which the upper end of the inner tube collides when the front fork strikes the bottom. This is achieved by interposing a shock absorbing cushion member that absorbs and reduces the shock generated due to the collision of the inner tube between the upper cap and the upper cap.

In other words, according to this, when the front fork strikes the bottom, the transmission of the shock generated by the upper cap and the inner tube abutting each other through the spacer to the handle is performed between the upper cap and the spacer. Can be absorbed and cushioned by the cushion member interposed between the upper cap and the spacer, and the occurrence of resonance due to the impact can be reliably cut between the upper cap and the spacer, thereby preventing the rider from feeling uncomfortable.

In addition, the above-mentioned cushion member is interposed between the upper cap and the spacer to prevent direct rubbing of the upper cap and the spacer during normal running, and to prevent metal powder due to wear of both. Of the fork is prevented from being mixed into the working oil, thereby preventing the operation failure of the front fork.

Further, at least one surface of the cushion member interposed between the upper cap and the spacer is formed in an uneven shape to increase elasticity, thereby improving the shock absorbing property of the cushion member. You can also.

Further, the claws can be raised from the inner diameter side of the cushion member, these claws can be pressed into the upper cap, and the cushion member can be integrated with the upper cap to improve the assembling property of the cushion member. You can do it.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a front fork for a motorcycle incorporating the shock absorbing mechanism according to the present invention will be described below.

FIG. 1 shows the upper part of a pair of two telescopic cylinders 2 in a front fork 1 for a motorcycle incorporating a shock absorbing mechanism according to the present invention in a most compressed state. The telescopic cylinder 2 constituting the main part of the fork 1 is configured as a telescopic column by an outer tube 3 and an inner tube 4 inserted in a telescope shape.

From the center of the bottom surface of the inner tube 4 (only the upper end portion is shown in the figure), the bottom surface is attached to the inner tube 4 and the damper mechanism 5 rises. The damper mechanism 5 can expand and contract upward from the damper mechanism 5. Is screwed into an upper cap 7 for closing the upper end of the outer tube 3, and then connected by tightening with a lock nut 8.

A cushion rubber 9 is fitted to the upper cap 7 with its lower end exposed to the inside of the outer tube 3. A spring guide 11 is interposed between the lower end of the cushion rubber 9 and a washer 10. Damper mechanism 5
Are provided along the piston rod 6.

The spring guide 11 is for preventing the suspension spring 12 from buckling due to the compression operation, and includes a step 13 provided on the lower inner surface and the piston rod 6 of the damper mechanism 5.
Is slidably fitted to the piston rod 6 of the damper mechanism 5 while being restricted by the engagement with the snap ring 14 provided in the above.

Thus, the spring guide 11 is locked to the piston rod 6 by the engagement of the step 13 and the snap ring 14 until the telescopic cylinder 2 reaches the vicinity of the maximum compression.
The spring guide 11 is operated together with the piston rod 6 without relative displacement.

The lower end of the spring guide 11 is opposed to the upper end of the damper mechanism 5. After the telescopic cylinder 2 reaches the vicinity of the maximum compression, the spring guide 11 is engaged by the two.
Of the snap ring 14 on the piston rod 6 side
From the washer, and the washer 10
And presses the cushion rubber 9 to provide a cushioning action when the telescopic cylinder 2 is compressed.

On the other hand, the suspension spring 12 is disposed between the damper mechanism 5 and the upper cap 7 so as to surround the spring guide 11, and the lower end is placed on the damper mechanism 5 and the other end is a spacer. 15, the outer tube 3 is brought into contact with the upper cap 7 of the outer tube 3, and a force in the extension direction is applied to the telescopic tube 2 including the outer tube 3 and the inner tube 4 by the restoring force of the suspension spring 12 through the damper mechanism 5. I have.

The upper cap 7 of the outer tube 3 is interposed between the upper cap 7 of the outer tube 3 and the spacer 15 on the suspension spring 12 side.
The shock absorbing cushion member 16 for absorbing and mitigating the shock generated by the collision of the inner tube 4 with the inner tube 4 is interposed.

Thus, the front fork 1 shown in FIG.
The telescopic cylinder 2 that forms the column, which is the main part, operates as described below.

That is, before the telescopic cylinder 2 reaches the vicinity of the maximum compression, the lower end of the spring guide 11 does not come into contact with the damper mechanism 5 and the spring guide 11 is engaged with the step 13 and the snap ring 14. Piston rod 6
, The spring guide 11 and the piston rod 6 are integrally held, and the suspension spring 12 is operated while being compressed.

On the other hand, when the telescopic cylinder 2 approaches the vicinity of the most compression and the lower end of the spring guide 11 comes into contact with the upper end of the damper mechanism 5, the step 13 is separated with the snap ring 14 left and the spring guide 11 is separated. Is pushed up by the upper end of the damper mechanism 5, and the cushion rubber 9 is pressed by the upper end of the spring guide 11 through the washer 10 to exert a cushioning action on the compression operation of the telescopic cylinder 2.

Finally, when the inner tube 4 strikes the bottom of the front fork 1 where the inner tube 4 reaches the most compressed state, the inner tube 4 passes through the spacer 15 and the cushion member 16 and receives an impact when the inner cap 4 is compressed by the upper cap 7. Absorb.

Moreover, in this case, the upper cap 7 for closing the upper end of the outer tube 3 and the suspension spring 1
The upper cap 7 and the spacer 15 are made of metal, and are both made of metal. The upper cap 7 and the spacer 15 are not in direct contact with each other, but are in contact with each other. Since they come into contact with each other with the interposition of 16, the working oil is not contaminated by those metal powders generated by wear.

In addition, in addition, the cushion member 1 described above
6 reliably cuts between the upper cap 7 and the spacer 15 the transmission of the shock generated when the front fork 1 strikes the bottom and the generation of resonance due to the shock, thereby preventing the rider from riding. Factors that cause pleasure can be eliminated.

FIGS. 2 and 3 are enlarged views of another embodiment of a shock absorbing cushion member interposed between the upper cap 7 and the spacer 15. FIG. Shock absorbing cushion member 16a shown
Is to form a projection 17 on at least one surface to form an uneven surface.
The elasticity as a is increased to improve the shock absorption as a cushion member.

On the other hand, the cushion member 16b incorporated in the telescopic cylinder 2 of the front fork 1b shown in FIG. 3 engages by raising the claw 18 from the inner diameter side and press-fitting the claw 18 into the upper cap 7. By integrating the cushion member 16b with the upper cap 7 by the engagement, the incorporation of the shock absorbing cushion member 16b is improved.

[0032]

As described above, according to the first aspect of the present invention, the spacer for supporting the upper end of the suspension spring, which is an abutting member against which the upper end of the inner tube collides when the front fork strikes the bottom, and the outer tube for the outer tube. A shock absorbing cushion member is provided between the upper cap and the upper cap to absorb and reduce the shock generated by the collision of the inner tube. The transmission of the shock generated by the tubes abutting each other through the spacer to the handle and the generation of resonance due to the shock are reliably cut between the upper cap and the spacer, causing discomfort to the rider. It can be prevented from being dull.

In addition, the upper cap and the spacer are both made of metal and are likely to rub against each other with the operation of the front fork. However, they do not come into direct contact with each other but with the cushion member interposed therebetween. Therefore, the working oil can also be prevented from being contaminated by the metal powder generated by the wear.

[0034] According to the second aspect of the present invention, at least one surface of the cushion member is formed in an uneven shape to enhance elasticity. It becomes possible to improve the shock absorption of the member by simple means.

Further, according to the third aspect of the present invention, the claws are raised from the inner diameter side of the cushion member, these claws are pressed into the upper cap, and the cushion member is integrated with the upper cap. In addition to the effects of the first or second aspect of the present invention, it is possible to improve the incorporation of a shock absorbing cushion member when a bottom bump occurs.

[Brief description of the drawings]

FIG. 1 is a partial vertical sectional front view showing the upper part of one of a pair of telescopic cylinders in a two-wheeled front fork incorporating a shock absorbing mechanism at the time of a bottom collision according to the present invention in a most compressed state.

FIG. 2 is an enlarged front view showing a modified example of a cushion member constituting a shock absorbing mechanism at the time of bottom bump occurrence according to the present invention.

FIG. 3 is a view showing an upper part of one telescopic cylinder of a pair of two in a front fork for a motorcycle using a cushion member according to still another embodiment of the present invention in the most compressed state as in FIG. 1; It is an enlarged partial longitudinal front view.

FIG. 4 is a partial vertical sectional front view showing an upper portion of one telescopic cylinder of a pair of two front forks for a motorcycle provided only with a cushion rubber for reducing a shock at the time of maximum compression which has been conventionally used. is there.

[Explanation of symbols]

 1, 1b Front fork 2 Telescopic tube 3 Outer tube 4 Inner tube 5 Damper mechanism 6 Piston rod 7 Upper cap 9 Cushion rubber 11 Spring guide 12 Suspension spring 14 Snap ring 15 Spacer 16, 16a, 16b Cushion member 17 Projection 18 Claw

Claims (3)

[Claims] 1. A collision between an inner tube and an upper cap closing an upper end of an outer tube between a spacer for supporting an upper end of a suspension spring, which is an abutting member against which an upper end of the inner tube collides when the front fork strikes the bottom. A front fork for a motorcycle, comprising a shock absorbing cushion member for absorbing and mitigating a shock generated thereby. In order to improve the shock absorbing property of a shock absorbing cushion member that absorbs and reduces the shock generated by the collision of the inner tube when the front fork strikes the bottom, at least the shock absorbing cushion member is used. The front fork for a motorcycle according to claim 1, wherein an uneven projection is formed on one surface of the cushion member. 3. The inner diameter side of the shock absorbing cushion member for improving the incorporation of the shock absorbing cushion member that absorbs and reduces the shock generated by the collision of the inner tube when the front fork strikes the bottom. The front fork for a motorcycle according to claim 1 or 2, wherein the cushion member is integrally attached to the upper cap by causing the pawl to rise from the upper part and press-fitting and engaging the claw into the upper cap.