JP4157670B2 - Front fork for motorcycle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
According to the present invention, the impact generated at the bottom thrust when the front fork is fully compressed, in particular, the impact generated at the bottom thrust at the time of ground contact after a motorcycle jump such as a motocross race is not caused to the rider through the steering wheel. The present invention relates to a front fork for a motorcycle equipped with an impact mitigation mechanism for preventing transmission of pleasure.
[0002]
[Prior art]
In a general front fork for a motorcycle, an outer tube that is telescopically inserted like the front fork 1c for a motorcycle shown in FIG. 4 to alleviate the impact input transmitted from the traveling road surface to the vehicle body through the front wheel. 3 and the inner tube 4 are used as a telescopic tube 2 having a double tube structure (in the figure, only one telescopic tube 2 arranged in parallel is shown).
[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 may be provided between the upper cap 7 of the outer tube 3 and the damper mechanism 5 provided on the inner tube 4 side. The shock input transmitted to the vehicle body is absorbed by the spring load of the suspension spring 12 and the generated damping force of the damper mechanism 5.
[0004]
In addition, in this case, particularly when the use object of the front fork 1c is a motorcycle for motocross racing, a large impact input that causes a bottom butt against the front fork 1c at the time of grounding after the jump is generated. Often it happens.
[0005]
Therefore, in that case, in addition to the above, the spring guide 11 interposed between the damper mechanism 5 and the upper cap 7 of the outer tube 3 was fitted into the upper cap 7 through the washer 10. While compressing the cushion rubber 9, the upper end of the inner tube 4 is finally brought into contact with the upper end flange of the spacer 15 so as to be mechanically suppressed by the upper cap 7.
[0006]
[Problems to be solved by the invention]
However, in the conventional front fork 1c configured as described above, the impact generated in the front fork 1c is easily transmitted from the spacer 15 to the outer tube 3 through the upper cap 7, and as a result, the inner tube 4 When the bottom butt is in contact with the spacer 15, the inner tube 4 strikes the spacer 15 violently, and the impact at that time is transmitted from the outer tube 3 to the steering handle through a bracket member (not shown) that is a mounting member to the vehicle body. Will cause discomfort.
[0007]
Furthermore, the vibration generated when the upper end of the inner tube 4 hits the spacer 15 when the front fork 1c bottoms out is transmitted to the outer tube 3 through the upper cap 7, and resonates in the internal space of the front fork 1c to produce a loud sound. There were also problems such as discomfort to the rider due to the sound.
[0008]
In addition to these, the spacer 15 is rubbed against the upper cap 7 of the outer tube 3 by the spring force of the suspension spring 12 even during normal traveling, and the upper cap 7 of the outer tube 3 and the spacer are also rubbed. Since both 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 into the working oil, which hinders the operation of the front fork 1c. It will also give.
[0009]
Therefore, the object of the present invention is to cut the transmission of the impact generated when the bottom of the front fork and the accompanying resonance sound are reliably cut in the middle to prevent the rider from feeling uncomfortable and to combine them. Thus, it is an object of the present invention to provide a front fork for a motorcycle equipped with a novel impact mitigation mechanism that can prevent the working oil from being contaminated by the worn metal powder.
[0010]
[Means for Solving the Problems]
The above-described object of the present invention is to provide an inner member between a spacer for supporting the upper end of a suspension spring, which is an abutting member that directly collides with the upper end of the inner fork when the bottom of the front fork hits, and an upper cap for closing the upper end of the outer tube. This is achieved by interposing a cushion member that absorbs and relaxes the impact generated by the collision of the tube and prevents direct contact between the upper cap and the spacer .
[0011]
In other words, according to this, when the front fork hits the bottom, the transmission of the impact generated by the upper cap and the inner tube colliding with each other through the spacer is interposed between the upper cap and the spacer. In addition to being able to absorb and cushion with the cushion member, it is possible to reliably cut off the generation of resonance due to the impact between the upper cap and the spacer, thereby preventing the rider from feeling uncomfortable.
[0012]
In addition, the cushion member described above is interposed between the upper cap and the spacer to prevent direct rubbing between the upper cap and the spacer during normal driving, and the working oil of the metal powder due to wear of both of them. This prevents the inside of the front fork from malfunctioning and prevents the front fork from malfunctioning.
[0013]
In addition, by forming at least one surface of the cushion member interposed between the upper cap and the spacer in a concavo-convex shape and improving the elasticity, it is possible to improve the shock absorption of the cushion member. .
[0014]
Furthermore, by incorporating the claws up from the inner diameter side of the cushion member and press-fitting these claws into the upper cap, and integrating the cushion member with the upper cap, the assemblability of the cushion member can be improved. .
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a motorcycle front fork incorporating an impact mitigation mechanism according to the present invention will be described below.
[0016]
FIG. 1 shows the upper part of one pair of telescopic cylinders 2 in a front fork 1 for a motorcycle incorporating an impact mitigation mechanism according to the present invention in the most compressed state. The telescopic cylinder 2 constituting the main portion is configured as a telescopic column by an outer tube 3 and an inner tube 4 inserted in a telescope shape.
[0017]
From the center of the bottom surface of the inner tube 4 (only the upper end portion is shown in the figure), the damper mechanism 5 stands up with the bottom surface attached to the inner tube 4, and the piston extends from the damper mechanism 5 so as to expand and contract. The rod 6 is joined by screwing the distal end portion of the rod 6 into the upper cap 7 for closing the upper end of the outer tube 3, and then tightening with the lock nut 8.
[0018]
A cushion rubber 9 is fitted to the upper cap 7 with its lower end exposed to the inside of the outer tube 3, and the spring guide 11 is placed on the damper mechanism 5 with a washer 10 sandwiched between the lower end of the cushion rubber 9. It is provided along the piston rod 6.
[0019]
The spring guide 11 is for preventing buckling of the suspension spring 12 accompanying the compression operation, and is limited by the engagement between the step portion 13 provided on the lower inner surface and the snap ring 14 provided on the piston rod 6 of the damper mechanism 5. While being received, the damper mechanism 5 is slidably fitted to the piston rod 6.
[0020]
Thus, until the telescopic cylinder 2 reaches the vicinity of the maximum compression, the spring guide 11 is locked to the piston rod 6 by the engagement of the step portion 13 and the snap ring 14, and the spring guide 11 is relative to the piston rod 6. They are designed to work together without displacement.
[0021]
Further, the lower end of the spring guide 11 is opposed to the upper end of the damper mechanism 5, and after the telescopic cylinder 2 reaches the vicinity of the most compression, the stepped portion 13 of the spring guide 11 is located on the piston rod 6 side due to the engagement between the two. It is configured to displace away from the snap ring 14 and to push the cushion rubber 9 through the washer 10 at the upper end in accordance with this displacement and to provide a cushioning action when the telescopic cylinder 2 is compressed.
[0022]
On the other hand, the suspension spring 12 surrounds the spring guide 11 and is disposed between the damper mechanism 5 and the upper cap 7. The lower end is placed on the damper mechanism 5 and the other end sandwiches the spacer 15. In this manner, the outer tube 3 abuts against the upper cap 7 and a force in the extending direction is applied to the telescopic cylinder 2 composed of the outer tube 3 and the inner tube 4 through the damper mechanism 5 by the restoring force of the suspension spring 12.
[0023]
Then, between the upper cap 7 in the outer tube 3 and the spacer 15 on the suspension spring 12 side, an impact absorbing member that absorbs and relaxes the impact generated by the collision of the inner tube 4 with the upper cap 7 of the outer tube 3. This cushion member 16 is interposed.
[0024]
Thus, the telescopic cylinder 2 constituting the column that is the main part of the front fork 1 shown in FIG. 1 operates as described below.
[0025]
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 piston rod 6 by the engagement of the step portion 13 and the snap ring 14. The spring guide 11 and the piston rod 6 are held together, and the suspension spring 12 is compressed and operated together.
[0026]
On the other hand, when the telescopic cylinder 2 comes close to the most compressed state and the lower end of the spring guide 11 comes into contact with the upper end of the damper mechanism 5, the stepped portion 13 leaves with the snap ring 14 left, and the spring guide 11 is moved away from the damper mechanism. 5 is pushed up by the upper end of the spring guide 11, and the cushion rubber 9 is pressed by the upper end of the spring guide 11 through the washer 10 to apply a cushioning action to the compression operation of the telescopic cylinder 2.
[0027]
And, finally, the inner tube 4 is in bottoming when the front fork 1 which has reached the lowest compression state, in Na tubes 4 absorbs the shock at the time of the most compressed upper cap 7 through the spacer 15 and the cushion member 16 .
[0028]
Moreover, in this case, the upper cap 7 that closes the upper end of the outer tube 3 and the spacer 15 for supporting the upper end of the suspension spring 12 are both made of metal and tend to rub against each other as the front fork 1 operates. Since the upper cap 7 and the spacer 15 are in contact with each other with the cushion member 16 interposed therebetween without being in direct contact, the working oil is not contaminated by those metal powders caused by wear.
[0029]
In addition, the cushion member 16 described above reliably transmits between the upper cap 7 and the spacer 15 the transmission of the impact generated when the front fork 1 bottoms out to the handle and the generation of resonance sound associated with the impact. Therefore, it is possible to remove the factor that makes the rider feel uncomfortable.
[0030]
2 and 3 are enlarged views of another embodiment of the shock absorbing cushion member interposed between the upper cap 7 and the spacer 15, and the shock shown in FIG. The cushion member 16a for absorption has projections 17 on at least one surface to form a concavo-convex surface, thereby improving the elasticity as the cushion member 16a for absorbing shock and improving the shock absorption as a cushion member. It is an improvement.
[0031]
On the other hand, the cushion member 16b incorporated in the telescopic cylinder 2 of the front fork 1b shown in FIG. 3 is engaged 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 16 b with the upper cap 7, the incorporation of the cushion member 16 b for absorbing shock is improved.
[0032]
As described above, according to the first aspect of the present invention, the upper end support spacer of the suspension spring, which is an abutting member with which the upper end of the inner tube directly collides with the bottom of the front fork, and the upper end of the outer tube are closed. By absorbing a shock generated by the collision of the inner tube between the cap and mitigating it, and by interposing a cushion member that prevents direct contact between the upper cap and the spacer, When the upper cap and the inner tube collide with each other through the spacer, the transmission of the shock generated by the handle and the generation of the resonance sound associated with the impact are also reliably cut between the upper cap and the spacer. Can prevent discomfort.
[0033]
In addition, the upper cap and the spacer are both made of metal and try to rub against each other with the operation of the front fork. It is also possible to prevent the working oil from being contaminated by those metal powders caused by abrasion.
[0034]
According to the invention of claim 2, in addition to the effect of the invention of claim 1 described above, at least one surface of the cushion member is formed in an uneven shape to enhance the elasticity. Absorbability can be improved by simple means.
[0035]
Furthermore, according to the invention of claim 3, 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 effect of the present invention, it is possible to improve the incorporation of the cushion member for absorbing shock when the bottom strike occurs.
[Brief description of the drawings]
FIG. 1 is a partial longitudinal front view showing an upper part of one telescopic cylinder of a set of two in a front fork for a motorcycle incorporating a shock mitigation mechanism when a bottom butt occurs 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 an impact mitigating mechanism when a bottom butt is generated according to the present invention.
3 similarly shows the upper part of one telescopic cylinder of a set of two in a front fork for a motorcycle using a cushion member of still another embodiment according to the present invention in the most compressed state as in FIG. It is an enlarged partial longitudinal sectional front view.
FIG. 4 is a partially longitudinal front view showing the upper part of one telescopic cylinder of a set of two front forks for a two-wheeled vehicle provided with only a cushion rubber that alleviates impact at the time of most compression that has been conventionally used. is there.
[Explanation of symbols]
1, 1b Front fork 2 Telescopic cylinder 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 Protrusion 18 Claw

Claims (3)

Between the upper cap when bottoming of the front fork upper end of the inner tube closing the upper end of the spacer and the outer tube for the upper end support of the suspension spring is a abutment member impinging directly generated with the collision of the inner tube A front fork for a two-wheeled vehicle comprising a cushion member that absorbs and relaxes an impact and prevents direct contact between an upper cap and a spacer .   In order to improve the shock absorption of the shock absorbing cushion member that absorbs and relaxes the shock generated by the collision of the inner tube at the bottom of the front fork, at least one of the shock absorbing cushion members The front fork for a two-wheeled vehicle according to claim 1, wherein uneven projections are formed on the surface.   In order to improve the incorporation of the shock absorbing cushion member that absorbs and relaxes the impact generated by the collision of the inner tube at the bottom of the front fork, the nail is raised from the inner diameter side of the shock absorbing cushion member. The front fork for a motorcycle according to claim 1 or 2, wherein the cushion member is integrally attached to the upper cap by press-fitting and engaging the claw into the upper cap.

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