JPH07277261A - Wheel suspension type front fork - Google Patents

Abstract

PURPOSE:To keep elastic cylinders from wear, make the elastic cylinders replaceable with high workability and enhance buffer action. CONSTITUTION:A support rod 20 is extended inside a sliding pipe 13. A plurality of elastic cylinders 21 are loosely fitted into the support rod 20 in such a way as to be kept out of contact. The elastic cylinders 21 are interconnected and integrated together by connectors 22, each of which is slidably fitted into the support rod 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel suspension type front fork for bicycles and other motorcycles.

[0002]

2. Description of the Related Art In a bicycle or the like, a wheel suspension type front fork is adopted in order to absorb the impact when the front wheels run on a step or the like.

As a conventional front fork of this type,
There is known a structure in which an elastic buffer cylinder made of rubber or the like is arranged in a sliding pipe that slides vertically with respect to a support pipe.
That is, the impact force applied to the sliding pipe that moves up and down due to the impact is absorbed by the elastic buffer cylinder. For example, in a front fork for a mountain bike, the elastic cushioning cylinder is designed so that the cushioning stroke (vertical movement interval) of the sliding pipe is about 50 mm. That is, in consideration of durability against repeated impact force, the total length of the elastic cushioning cylinder is set to about 3 times (150 mm) the cushioning stroke, and the diameter thereof is set to about 20 mm.

By the way, when the length of the entire length of the elastic cushioning cylinder is larger than the diameter of the elastic cushioning cylinder, the elastic cushioning cylinder causes buckling when the impact force is repeatedly applied, and the durability is deteriorated.

Therefore, the rod is inserted through the elastic buffer cylinder,
A front fork having a structure capable of preventing the buckling has been put into practical use. However, in such a structure, when the elastic cushioning cylinder is elastically deformed by receiving an impact force, the cushioning cylinder is worn by sliding contact with the rod, causing buckling in a short period of time and being damaged.

For this reason, recently, a front fork having a buckling prevention structure in which a plurality of elastic cylindrical bodies each having a small length is fitted to a rod through a spacer has been proposed and put into practical use.

[0007]

However, even in the above-described buckling prevention structure, since the plurality of elastic cylinders are slidably fitted to the rods, it is possible to prevent the elastic cylinders from being worn by the rods. Therefore, there is a possibility that the elastic cylinder may be damaged. Further, when frictional force is applied to the elastic cylinder by the rod, it takes some time for the elastic cylinder to return to its original shape after being deformed by impact force. The impact force was often applied again before returning to, and a sufficient cushioning effect could not be expected.

On the other hand, the front fork having the above-described buckling prevention structure has an advantage that elastic cylinders having different elastic forces can be selected and replaced according to the running condition of a bicycle or the like.
However, since the plurality of elastic cylinders and spacers are individually and independently fitted to the rod, the elastic cylinders and spacers must be removed from the rod and fitted together one by one. It takes a lot of time and labor for work.

There is also known a structure in which a bulge stopper is provided at the lower end of the rod to prevent the elastic cylinder from coming out, and the rod and the plurality of elastic cylinders are integrally removed from the front fork in a skewed state. In this case, it is necessary to remove the rod from the support pipe, further remove the elastic cylindrical body from the rod, and perform the troublesome attachment and detachment work for attaching the rod again.

The present invention has been made in order to solve the above problems, and provides a wheel suspension type front fork which does not wear the elastic cylinder and which can be replaced with good workability and which has an excellent cushioning effect. With the goal.

[0011]

SUMMARY OF THE INVENTION The present invention is directed to a pair of support pipes fixedly mounted on the steering pipe side, and a pair of slides slidably fitted to the support pipes and provided with wheel bearings at their lower ends. In a wheel suspension type front fork including a pipe, a support rod supported on the support pipe side and extending into the sliding pipe, and an impact force applied to the sliding pipe by being loosely fitted to the support rod through a through hole are provided. It is characterized in that it has a plurality of elastic cylinders that absorb, and a connecting body that connects the elastic cylinders to each other and is slidably fitted to the support rod.

[0012]

The plurality of elastic cylinders are loosely fitted to the bearing rod, and the connecting body is fitted to the bearing rod. Therefore, since the elastic tubular body does not come into direct sliding contact with the bearing rod, it does not wear and instantly returns to its original shape. Further, since the plurality of elastic cylinders are integrally connected by the connecting body, they can be removed from the support rod and mounted together.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows an example in which a wheel suspension type front fork according to the present invention is applied to a front wheel of a bicycle,
It is a front view showing a half section. FIG. 2 is an exploded perspective view showing a main part of the front fork.

First, in FIG. 1, 10 is a steering pipe, and a handlebar is attached to the upper end of the steering pipe 10 via an estension system (not shown). The lower end of the steering pipe 10 is press-fitted and fixed to the center of the upper crown 11.
Upper portions of a pair of support pipes 12 are fixedly fitted to both arm portions 11 a of the upper crown 11. An upper part of a sliding pipe 13 is slidably fitted to a lower part of each support pipe 12.

That is, a sliding cylinder 14 made of polyamide resin is fixed to the inner peripheral wall of the upper half of each sliding pipe 13, and the sliding pipe 13 slides vertically on the support pipe 12 via the sliding cylinder 14. It is movably fitted. Sliding pipe 13
A connecting cylinder 15 is fixedly fitted to the upper outer peripheral wall of the. The support pipe 12 is provided on the inner peripheral surface of the upper end of the connecting cylinder 15.
A dust seal material 29 made of an elastic body that is in contact with the peripheral surface of the is attached. Further, the lower end of the bellows 16 for dust protection is connected to the upper end of the connecting tubular body 15, and the upper end of the bellows 16 is fixed to the step portion of the upper crown 11. The upper part of each connecting cylinder 15 is connected to each other by a cross member 17, and a brake cable (not shown) is fixed to the upper part of the cross member 17. A brake pedestal 18 for mounting a brake device (not shown) is provided below the connecting cylinder 15.

A stopper 19 is screwed and fixed to the lower end of the support pipe 12. The upper end of the support rod 20 is screwed and fixed to the center of the stopper 19. The bearing rod 20 extends in the sliding pipe 13 along its central axis. A plurality of elastic cylinders 2 are mounted on the supporting rod 20.
1 is loosely fitted. That is, each elastic cylinder 21 is made of rubber, and as shown in FIGS. 1 and 2, a through hole 21a having a diameter sufficiently larger than the diameter of the supporting rod 20 is provided, and the supporting rod 20 is inserted into the through hole 21a. Has been inserted.

The upper and lower elastic cylinders 21, 21 are connected to each other by a connecting body 22. The connecting body 22 is made of polyamide resin, polyacetal resin, or the like, and has a cylindrical portion 22a.
And a disk portion 22b radially expanded from the central peripheral surface of the cylindrical portion 22a. The cylindrical portion 22a has an outer diameter that is press-fitted into the through hole 21a of the elastic tubular body 21, and the support rod 2
0, and has an inner diameter that slidably fits over the surface. Both ends of the cylindrical portion 22a are press-fitted into the through holes 21a, 21a of the upper and lower elastic cylindrical bodies 21, 21, respectively, and in this press-fit state, both sides of the disk portion 22b are elastic cylindrical bodies 21, 21.
1 is abutted on the opposite end faces. As a result, the plurality of elastic cylinders 21 are connected to each other by the connecting body 22 and have an integral connecting structure. On the other hand, the plurality of elastic cylinders 21 connected to each other are connected to each other on the support rod 20.
The upper end surface of the uppermost elastic cylindrical body 21 is abutted against the lower surface of the stopper 19 through loose fitting. The lowermost elastic tubular body 21 is supported by a support fitting 23, and the lower end of the support rod 20 is located in the support fitting 23. The support fitting 23 is screwed and held by an axle bearing portion 24 fixed to the lower end of the sliding pipe 13.

A rebound member 25 is arranged on the stopper 19. The rebound member 25 is formed into a cylindrical shape by using an elastic plastic resin or the like, and an elastically expanding and contracting bellows portion is provided on an upper portion thereof. A stopper pin 26 is in contact with the upper surface of the rebound member 25. The stopper pin 26 is screwed into the lower portion of the connecting tubular body 15, penetrates through the sliding pipe 13 and the sliding barrel 14, and projects below the vertically elongated hole 12A provided in the support pipe 12, and in this state, the rebound member. It is in contact with 25.

Next, the operation of the front fork according to the present invention will be described. When a front wheel is attached to the axle bearing portion 24 via the axle, when an impact force is applied to the front wheel, the sliding pipe 13 moves upward against the elastic force of the plurality of elastic cylinders 21 and slides. It slides upward on the support pipe 12 via the tube 14. Therefore, the impact force can be absorbed by the elastic contraction deformation of the plurality of elastic cylinders 21.

After that, the sliding pipe 13 is pushed down by the restoring force of each deformed elastic cylindrical body 21, but in this case, the stopper pin 26 abuts the rebound member 25 and moves down while deforming the rebound member 25. , Sliding pipe 1
3 can be smoothly returned to the original extended state.

By the way, the plurality of elastic cylinders 21 are loosely fitted to the support rod 20 so as to maintain a large gap.
Moreover, they are coaxially fitted to each other via the connecting body 22. Therefore, the elastic cylindrical body 21 does not come into contact with the peripheral surface of the bearing rod 20 even if it is deformed by an impact force, and therefore, it does not wear even if it is repeatedly elastically deformed, so that it can be used for a long period of time. And the durability is greatly improved. Further, when the elastic cylindrical body 21 elastically deforms without contacting the supporting rod 20, the elastic cylinder 21 immediately returns to the original shape, so that even if an impact force is continuously applied, it can be sufficiently buffered. Further, since the plurality of elastic cylinders 21 are integrally connected by the connecting body 22 and the connecting body 22 slides on the bearing rod 20 with low friction, the elastic cylinders 21 and the connecting body 22 are integrated. It can be detached from the support rod 20 and mounted again. Therefore, the elastic cylindrical body 21 can be replaced with good workability in accordance with running conditions and the like.

FIG. 3 shows another embodiment of the present invention.
That is, in this embodiment, the uppermost elastic cylinder 21 and the stopper 19 are connected by the connecting body 22, and the lowermost elastic cylinder 21 and the support fitting 23 are connected by the connecting body 22. That is, each connecting body 22 includes a stopper 19 and a support fitting 23.
And is similarly press-fitted into the elastic cylindrical body 21.
Then, the upper part of the support rod 20 penetrates the stopper 19 upward and extends into the rebound member 25, and the cap 27 is attached to the upper end. This cap 27 has a stopper pin 26 in a state in which a cylindrical adhered portion penetrates the upper wall surface of the rebound member 25 and its flange portion is locked to the upper wall surface.
Is in contact with. Therefore, the support rod 20 is held by the rebound member 25 so as not to slip out. still,
In the embodiment of FIG. 3, the same parts as those of FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

FIG. 4 shows still another embodiment. In this embodiment, the upper portion of the support rod 20 penetrates the stopper 19 upward to extend into the rebound member 25, and further penetrates the rebound member 25 to abut the stopper pin 26. A retaining ring 28, which is engaged with the upper surface of the stopper 19, is fixedly fitted to the support rod 20. Therefore, similarly, the bearing rod 20 is held by the retaining ring 28 so as not to slip out. Also in this embodiment, the same parts as those in FIG.

[0000]

According to the present invention, a plurality of elastic cylinders are loosely fitted to a supporting rod extending in a sliding pipe so as to maintain a non-contact state, and a connecting body for connecting these elastic cylinders to each other. Since it is slidably fitted to the bearing rod, wear of the elastic cylinder can be prevented and its durability can be improved, and the elastically deformed elastic cylinder is instantly restored to its original shape. Since it is possible to reliably absorb the repeatedly applied impact force, and it is possible to collectively remove and install a plurality of elastic cylinders from the support rod, the elastic cylinder replacement work can be performed easily. It can be carried out.

[Brief description of drawings]

FIG. 1 is a front view showing a cross section of a half portion of a wheel suspension type front fork of a bicycle according to the present invention.

FIG. 2 is an exploded perspective view of a main part of the front fork.

FIG. 3 is a cross-sectional view of a main part according to another embodiment of the present invention.

FIG. 4 is a sectional view of an essential part according to still another embodiment of the present invention.

[Explanation of symbols]

 12 Support Pipe 13 Sliding Pipe 19 Stopper 20 Bearing Rod 21 Elastic Cylindrical Body 21a Through Hole 22 Connecting Body 25 Rebound Member 26 Stopper Pin 27 Cap 28 Retaining Ring

Claims (3)

[Claims] 1. A wheel comprising a pair of support pipes fixedly attached to the steering pipe side, and a pair of slide pipes slidably fitted to the pair of support pipes and provided with an axle bearing at a lower end thereof. In a suspension-type front fork, a supporting rod that is supported by the supporting pipe and extends into the sliding pipe, and a through hole that is loosely fitted in the supporting rod are provided to absorb impact force applied to the sliding pipe. A wheel suspension type front fork, comprising: a plurality of elastic cylinders, and a connecting body that connects the elastic cylinders to each other and is slidably fitted to the support rod. 2. A stopper fixed to the lower end of the support pipe and brought into contact with the uppermost elastic cylinder, and a rebound arranged in the support pipe to press the stopper toward the elastic cylinder. Member and a stopper that penetrates and is fixed to the upper portion of the sliding pipe in the radial direction, is movably engaged in an axial long hole of the support pipe, and is abutted to the other end of the rebound member. The wheel suspension type front fork according to claim 1, further comprising a pin. 3. The cylindrical body is press-fitted into a through hole of the elastic cylindrical body, and the connecting body is radially expanded from the center of the peripheral surface of the cylindrical body and abuts against the end surface of the elastic cylindrical body. The wheel suspension type front fork according to claim 1, wherein the front fork comprises a disc portion.