JPS6020549Y2 - front fork - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dual-tube front fork, and particularly relates to improvements in the mounting mechanism for the damping force generating valve and piston that are attached to the tip of the inner tube.

BACKGROUND ART In recent years, with the demand for lighter vehicle bodies in motorcycles and the like, there has been a desire for lighter front forks.

As a countermeasure, attempts have been made to make the outer tube and inner tube thinner.

By the way, at the tip of the inner tube, as shown in FIG.
are attached, and these are fixed to the inner tube 1 with a snap ring 5.

Therefore, if the wall thickness of the inner tube 1 is made thinner for the above purpose, sufficient strength cannot be obtained due to the relationship between the groove diameter of the snap ring 5 and the remaining thickness, and in the end, fixation with the snap ring 5 becomes impossible.

For this reason, conventionally, the piston 4 and the like have been fixed to the inner tube 1 by using a nut or the like with a threaded outer periphery instead of the snap ring 5, and by using an adhesive to prevent the nut from loosening.

However, with this method, once it is fixed, it is very difficult to replace the valve 2, etc. (the nut cannot be removed), so there is a maintenance drawback in that the damping force cannot be adjusted.

This is especially fatal for factory racers who need to set the damping force.

The present invention was proposed in view of these points, and while the valve mechanism is fixed with a nut, a snap ring is used to prevent the nut from loosening, making it possible to reduce the thickness of the inner tube and adjust the damping force. The purpose is to provide a front fork with a new design.

Hereinafter, embodiments of the present invention will be described based on the drawings.

Figure 2 is a diagram showing the valve area of the present invention, in which 10 is an outer tube connected to the axle side, 11 is a hollow pipe installed vertically at the bottom of the outer tube 10, and 12 is connected to the vehicle body side. The inner tube 12 is slidably inserted into the outer tube 10.

A valve 13 (along with a valve stopper 14) for generating rebound damping force is provided on the inner peripheral surface of the tip of the inner tube 12.
A piston 15 for generating a compression side damping force is assembled, and oil chambers A and B are formed on the upper and lower surfaces of the piston 15.

Therefore, when operating on the compression side, hydraulic oil flows smoothly from oil chamber B to A, but when operating on the rebound side, the valve 13 provides resistance to the flow of hydraulic oil from oil chamber A to B, and a predetermined damping force is obtained. It looks like this.

As can be seen in FIG. 3, the valve 13 and the annular piston 15 are ring-shaped with a thread cut on the outer periphery to be screwed into a threaded part 16 carved on the inner peripheral surface of the tip of the inner tube 12 to prevent removal. It is fixed by a nut 17.

This nut 17 is further prevented from rotating relative to the inner tube 12 by a snap ring 18 to prevent binding during operation.

That is, as shown in FIGS. 4A and 4B, an annular groove 19 is formed on the inner peripheral surface of the nut 17 at approximately the center thereof, and a through hole is formed extending from the annular groove 19 to the outer periphery of the nut 17. 20 is formed.

On the other hand, one through hole 21 is also formed in the threaded end portion 16 of the inner tube 12 in correspondence with the aforementioned through hole 20 (see FIG. 3).

Therefore, after the nut 17 is screwed into the inner tube 12, these through holes 20 and 21 are simultaneously machined from the outer circumferential side of the inner tube 12 using a drill or the like.

A semicircular snap ring 18 as shown in FIG. 5 is fitted into the annular groove 19, and a projection 18a formed by bending one end outward connects the through holes 20 and 21. It penetrates (see Figure 3).

The nut 17 is prevented from rotating relative to the inner tube 12 by the engagement of the protrusion 18a, but the snap ring 18 is pulled outward against the annular groove 19 of the nut 17 by its spring force, so it comes off during operation. That's not the case.

In this way, since the valve mechanism and the piston 15 are fixed with the nut 17, the threaded part 16 that has almost no effect on the wall thickness can be machined at the tip of the inner tube 12, and therefore the threaded part 16 can be machined within the allowable range in terms of strength. It is possible to make the inner tube 12 thinner.

Also, if the nut 17 is loosened during operation, the snap ring 18
Since the nut 17 can be rotated by removing the snap ring 18 from the annular groove 19 with a pin or the like, the nut 17 can be removed, making it possible to replace the valve 13 etc. and adjust the damping force. Can be done.

As explained above, according to the present invention, the inner tube can be thinned while maintaining the required strength, and the damping force setting can be easily adjusted.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional device, Fig. 2 is a partially cutaway front view showing the valve area of the present invention, Fig. 3 is a sectional view taken along line I-I in Fig. 2, and Fig. 4 A and B are nuts. Section and front view of 5th
The figure is a front view of the snap ring. 10... Outer tube, 12...
Inner tube, 13...Valve, 15...
...Piston, 17...Nutto, 18...
...Snap ring, 18a...Protrusion,
20.21...Through hole.

Claims (1)

[Scope of utility model registration request] A damping valve and a piston are inserted into the inner circumferential surface of the tip of the inner tube that is freely slidably inserted into the outer tube, and a ring-shaped nut is screwed to fix the inner tube in the axial direction, while a snap ring is attached to the inner surface of the nut. A front fork, which is fitted into a nut and has one end passed through a through hole formed in a nut and an inner tube.