JP3283994B2 - Wheel suspension type front fork - Google Patents

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 employed in order to absorb an impact when a front wheel rides 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 disposed in a sliding pipe that slides up and down 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, an elastic shock absorbing cylinder is designed such that a shock absorbing stroke (a vertical movement interval) of a sliding pipe is about 50 mm. That is, in consideration of the durability against the repeated impact force, the total length of the elastic shock absorbing cylinder is set to about three times (150 mm) the shock absorbing stroke, and the diameter thereof is set to about 20 mm.

When the length of the entire length of the elastic cushioning cylinder is larger than the diameter of the elastic cushioning cylinder, the elastic buffering cylinder buckles when impact force is repeatedly applied, and the durability is reduced.

Therefore, the rod is inserted through the elastic buffer cylinder,
A front fork having a structure capable of preventing the buckling has been put to practical use. However, in such a structure, when the elastic buffer cylinder is elastically deformed by receiving an impact force, there is a problem that the buffer cylinder is worn by sliding contact with the rod, buckling occurs in a short time, and is broken.

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

[0007]

However, even in the buckling prevention structure described above, since the plurality of elastic cylinders are slidably fitted to the rods, wear of the elastic cylinders by the rods can be prevented. Therefore, the elastic cylinder may be similarly damaged. Also, when a 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 the impact force. In many cases, the impact force was applied again before returning to the above, 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 an elastic cylindrical body having a different elastic force can be selected and replaced according to running conditions of a bicycle or the like.
However, since the plurality of elastic cylinders and spacers are individually fitted to the rods independently, the elastic cylinders and spacers must be removed from the rod and fitted one by one. A lot of trouble and time are required for the work.

There is also known a structure in which a bulging stopper is provided at the lower end of the rod to prevent the elastic cylinder from coming off, 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, remove the elastic cylinder from the rod, and perform a troublesome installation and removal operation for mounting the rod again.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a wheel suspension type front fork which can be exchanged with good workability without abrasion of an elastic cylindrical body, and which is excellent in cushioning action. With the goal.

[0011]

According to the present invention, there is provided a pair of support pipes fixedly attached to a steering pipe side, and a pair of slide pipes which are slidably fitted to these support pipes and provided with an axle bearing at a lower end. In a wheel suspension type front fork comprising 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 supporting rod through a through hole. It is characterized by having a plurality of elastic cylinders to be absorbed and a coupling body which interconnects the elastic cylinders and is slidably fitted to the support rod.

[0012]

The plurality of elastic cylinders are loosely fitted to the support rod, and the connecting body is fitted to the support rod. Therefore, since the elastic cylinder does not directly slide on the support rod, it does not wear and instantaneously returns to its original shape. Further, since the plurality of elastic cylinders are integrally connected by the connecting body, they can be detached from the support rod at a time and mounted.

[0013]

Embodiments of the present invention will be described below 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 which shows a half part in cross section. FIG. 2 is an exploded perspective view showing a main part of the front fork.

First, in FIG. 1, reference numeral 10 denotes a steering pipe, and a handlebar is attached to an upper end of the steering pipe 10 via an unillustrated esthesion system. The lower end of the steering pipe 10 is pressed into the center of the upper crown 11 and fixed.
Upper portions of a pair of support pipes 12 are fixedly fitted to both arm portions 11a, 11a of the upper crown 11. An upper portion of a sliding pipe 13 is slidably fitted to a lower portion of each support pipe 12.

That is, a sliding cylinder 14 made of a 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 supporting pipe 12 through the sliding cylinder 14. It is movably fitted. Sliding pipe 13
A connecting tubular body 15 is fixedly fitted to the upper outer peripheral wall of the connector. A support pipe 12 is provided on the inner peripheral surface of the upper end of the connecting cylinder 15.
A dust seal member 29 made of an elastic material that comes into contact with the peripheral surface of the rim is attached. The lower end of a dustproof bellows 16 is connected to the upper end of the connecting cylinder 15, and the upper end of the bellows 16 is fixed to the step of the upper crown 11. The upper part of each connecting cylinder 15 is mutually connected 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.

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

The upper and lower elastic cylinders 21 and 21 are connected to each other by a connector 22. The connecting body 22 is formed of a polyamide resin, a polyacetal resin, or the like, and has a cylindrical portion 22a.
And a disk portion 22b whose diameter is increased in the radial direction from the central peripheral surface of the cylindrical portion 22a. The cylindrical portion 22a has an outer diameter press-fit into the through hole 21a of the elastic cylindrical body 21 and the support rod 2
And an inner diameter that slidably fits on the upper side. Both ends of the cylindrical portion 22a are press-fitted into the through holes 21a, 21a of the upper and lower elastic cylinders 21, 21 respectively.
1 are in contact with the opposite end faces. Thereby, the plurality of elastic cylinders 21 are mutually connected by the connecting body 22 to have an integrated connection structure. On the other hand, the plurality of connected elastic cylinders 21
The upper end surface of the uppermost elastic cylinder 21 is in contact with the lower surface of the stopper 19. The lowermost elastic cylinder 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 24 fixed to the lower end of the sliding pipe 13.

On the stopper 19, a rebound member 25 is arranged. The rebound member 25 is formed in a cylindrical shape with an elastic plastic resin or the like, and is provided with a bellows portion which elastically expands and contracts at an upper portion. 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 cylinder 15, penetrates through the sliding pipe 13 and the sliding cylinder 14, and projects below the vertically long hole 12 </ b> A 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 an impact force is applied to the front wheel when the front wheel is mounted on the axle bearing portion 24 via the axle, 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.

Thereafter, the sliding pipe 13 is pushed down by the restoring force of each deformed elastic cylinder 21. In this case, the stopper pin 26 comes into contact with the rebound member 25 and moves downward while deforming the rebound member 25. , Sliding pipe 1
3 can be smoothly returned to the original extended state.

The plurality of elastic cylinders 21 are loosely fitted to the support rod 20 so as to maintain a large gap.
In addition, they are coaxially fitted via the connecting body 22. Therefore, the elastic cylinder 21 does not come into contact with the peripheral surface of the support rod 20 even when deformed by an impact force, and therefore does not wear even if it is repeatedly elastically deformed. And the durability is greatly improved. In addition, when the elastic cylinder 21 is elastically deformed without contacting the support rod 20, it immediately returns to its original shape, so that even if an impact force is continuously applied, the shock can be sufficiently buffered. Furthermore, since the plurality of elastic cylinders 21 are integrally connected by the coupling body 22 and the coupling body 22 slides on the support rod 20 with low friction, these elastic cylinders 21 and the coupling body 22 are collectively assembled. It can be removed from the support rod 20 and attached. Therefore, the elastic cylinder 21 can be replaced with good workability in accordance with the running conditions and the like.

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

FIG. 4 shows still another embodiment. In this embodiment, the upper portion of the support rod 20 penetrates upward through the stopper 19 and extends into the rebound member 25, and further passes through the rebound member 25 and abuts on the stopper pin 26. Further, a retaining ring 28 locked on the upper surface of the stopper 19 is fixedly fitted to the support rod 20. Accordingly, the bearing rod 20 is similarly held undetachably via the retaining ring 28. 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 support rod extending into a sliding pipe so as to maintain a non-contact state, and a connecting body for interconnecting these elastic cylinders. Is slidably fitted to the support rod, so that the wear of the elastic cylinder can be prevented and its durability can be improved, and the elastic cylinder that has been elastically deformed can be instantly returned to its original shape. The impact force applied repeatedly can be reliably buffered, and moreover, a plurality of elastic cylinders can be removed and attached collectively from the support rod, so that the work of replacing the elastic cylinder can be performed with good workability. It can be carried out.

[Brief description of the drawings]

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

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

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 Support pipe 13 Sliding pipe 19 Stopper 20 Support rod 21 Elastic cylinder 21a Through hole 22 Connector 25 Rebound member 26 Stopper pin 27 Cap 28 Retaining ring

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B62K 25/00-25/32 F16F 7/00 F16F 15/00 F16F 3/08

Claims (3)

(57) [Claims] 1. A wheel comprising: a pair of support pipes fixedly attached to a steering pipe side; and a pair of slide pipes slidably fitted to the pair of support pipes and having a lower end provided with an axle bearing. The suspension type front fork has a support rod supported by the support pipe and extending into the slide pipe, and a through hole that is loosely fitted to the support rod to absorb an impact force applied to the slide pipe. A wheel suspension type front fork, comprising: a plurality of elastic cylinders which are connected to each other; and a coupling body which interconnects the elastic cylinders and is slidably fitted to the support rod. 2. A stopper fixed to a lower end of the support pipe and contacting the uppermost elastic cylinder, and a rebound disposed in the support pipe and having one end pressing the stopper toward the elastic cylinder. A member and a stopper penetrated and fixed in a radial direction above the sliding pipe, movably engaged in an axial long hole of the support pipe, and abutted against the other end of the rebound member. The wheel suspension type front fork according to claim 1, further comprising a pin. 3. The connecting body has a cylindrical portion which is press-fitted into a through hole of the elastic cylindrical body, and has a diameter which is increased in a radial direction from a center of a peripheral surface of the cylindrical portion and is brought into contact with an end surface of the elastic cylindrical body. The wheel suspension type front fork according to claim 1, comprising a disc portion.