JPH03284492A - Front fork for motorcycle - Google Patents

Abstract

PURPOSE:To keep off the falling and breakdown of a dust seal so effectively by forming a protector guide so as to surround an outer circumferential part of the dust seal being attached to the lower end of an outer tube, and having the outer circumferential part of the dust seal held in between by the lower end of the outer tube and the protector guide. CONSTITUTION:A motorcycle front fork is provided with an inner tube 11 supported on a front wheel, an outer tube 10 housing this inner tube 11, a dust seal 20a being attached to a lower part of the outer tube 10, and a protector guide 18a clamping a protector 17 protecting the inner tube 11. In this case, the protector guide 18a is set to be larger in width length than the conventional one, and it is formed so as to have most of the dust seal 20a surrounded. A lower end of the protector guide 18a is bent inward, setting it down to a bending part 22. Then a ring projection 21 of the dust seal 10a is held between the lower end of the outer tube 10 and this bending part 22 of the protector guide 18a and clamped tight.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a front fork for a motorcycle, and in particular, to prevent a dust seal from falling off or being damaged, and to easily attach and detach the dust seal. This invention relates to a front fork for motorcycles that is capable of

(Prior Art) Generally, a motorcycle is constructed as shown in FIGS. 3(A) and 3(B). That is, a front fork 2 is disposed in front of a vehicle body frame 1, and this front fork 2
The front wheel 3 is supported by.

Further, a rear wheel 5 is supported at the other end of a swing arm 4 whose one end is pivotally supported at the front lower part of the vehicle body frame 1.
is buffered by a reaction unit (not shown). Furthermore, an engine 6 is arranged at the lower center of the vehicle body frame 1, and a fuel tank 7 and a seat 8 are installed at the upper part of the vehicle body frame 1. The rider straddles the seat 8 and steers the handlebar 9 to drive the motorcycle.

Incidentally, the front fork 2 is an inverted front fork, and an inner tube 11 is provided in an outer tube 10 so as to be telescopically housed therein, and an oil damper (not shown) is built into the outer tube 10. The outer tube 10 includes an upper bracket 12, an under bracket 13, and a steering shaft (
(not shown), it is rotatably supported by the vehicle body frame 1 in the horizontal direction. Further, a front axle bracket 14 is fixed to the lower end of the inner tube 11, as shown in FIG.
The front axle 15 of the front wheel 3 is pivotally supported by.

The front fork 2 composed of the outer tube 10 and the inner tube 11 absorbs shock from the front wheel 3 and damps vibrations.

Now, in the above-described inverted front fork 2, the inner tube 11 is arranged at the lower front of the vehicle body, so a protector device 16 is installed to protect the inner tube 11 from flying stones etc. flying from the front of the vehicle. be done. As shown in FIGS. 3(A) and (B) and FIG. 4, this protector device 16 includes a protector 17 disposed in front of the inner tube 11 and a protector guide fixed to the lower end of the outer tube 10. 18.

The upper end of the protector 17 is held movably in the axial direction by a protector guide 18 fixed to the lower end of the outer tube 10 with a bolt.
The lower end of 7 is fixed to the front axle bracket 14 with bolts or screws. Therefore, when the front fork 2 telescopically extends and contracts, the upper end of the protector 17 is slidably moved by the protector guide 18, but is held at a fixed position on the front surface of the inner tube 11. Therefore, this protector 17
This effectively protects the inner tube 11 from flying stones and the like.

On the other hand, as shown in FIG.
0 is provided with an oil damper (not shown). In order to prevent the oil filled in the outer tube 10 from leaking to the outside, the outer tube 10
An oil seal 19 is disposed between the inner tube 11 and the inner tube 11 . Further, in order to prevent mud, dust, etc. attached to the outer surface of the inner tube 11 from entering toward the oil seal 19 due to the reciprocating movement of the inner tube 11, a dust seal 20 is fitted in the lower end opening of the outer tube 10. has been done.

(Problem to be Solved by the Invention) However, in the front fork for a motorcycle configured as described above, mud and dust tend to accumulate on the upper surface of the front axle bracket and the surface of the inner tube. When the inner tube is reciprocated, there is a risk that the dust seal may be damaged by external force due to dust or the like, or fall off from the outer tube.

Furthermore, if the motorcycle is driven with the dust seal falling off, the oil seal is also likely to be damaged, increasing the risk that the oil for the oil damper will leak and the front fork will lose its function.

In particular, conventional dust seals have been installed with most of them exposed to the outside, so they have the disadvantage of being easily damaged or falling off due to direct collision with flying stones.

On the other hand, in order to prevent the dust seal from falling off, a structure is also adopted in which the amount of press-fitting of the dust seal into the outer tube is set large, as shown in FIG. In this way, by setting a large press-fit allowance, it is possible to effectively prevent the dust seal from falling off to some extent, but on the other hand, it becomes difficult to remove the dust seal during maintenance, resulting in a reduction in work efficiency. .

The present invention was made in order to solve the above problems, and an object of the present invention is to provide a front fork for a motorcycle that can effectively prevent the dust seal from falling off or being damaged, and can be easily attached and detached. do.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an inner tube supported by a front wheel, an outer tube that telescopically accommodates the inner tube, and an inner tube attached to the lower end of the outer tube. In a front fork for a motorcycle, the front fork is equipped with a dust seal that prevents dust from entering, and a protector guide that is attached to the lower end of the outer tube and fixes a protector that protects the inner tube. The present invention is characterized in that a protector guide is formed, and the outer circumference of the dust seal is held between the lower end of the outer tube and the protector guide.

(Function) According to the front fork for a motorcycle having the above configuration, since the protector guide is formed in a large size so as to surround the outer periphery of the dust seal, flying objects such as flying stones do not directly collide with the dust seal. becomes less. Therefore, it is possible to effectively prevent the dust seal from being damaged or falling off.

Further, since a structure is adopted in which the outer peripheral portion of the dust seal is held between the lower end of the outer tube and the protector guide, it is possible to prevent the dust seal from falling off from the outer tube. Furthermore, since the amount of press-fitting of the dust seal into the outer tube can be shortened, the dust seal can be easily removed and installed during maintenance, and the work efficiency of maintenance can be greatly improved.

(Example) Next, an example of the present invention will be described with reference to the accompanying drawings.

1A and 1B are a side view and a front view, respectively, showing an embodiment of a front fork for a motorcycle according to the present invention, and FIG. 2 is a partial sectional view showing the structure of a dust seal portion. . In addition, Figures 3 (A), (B), and 4
Elements that are the same as those of the conventional example shown in FIGS. and FIG.

That is, the front fork for a motorcycle according to this embodiment includes an inner tube 11 supported by the front wheel 3 via a front axle bracket 14, and an inner tube 11.
an outer tube 10 that telescopically accommodates the outer tube 1 which is attached to the lower end of the outer tube 10;
In the front fork for a motorcycle, the front fork for a motorcycle is provided with a dust seal 20a that prevents dust from entering into the inside of the fork, and a protector guide 18a that is attached to the lower end of the outer tube 10 and fixes the protector 17 that protects the inner tube 11. A protector guide 18a is formed to surround the outer periphery of the dust seal 20a, and the lower end of the outer tube 10 and the protector guide 1
The outer circumferential portion of the dust seal 20a is sandwiched between the lower end portion of the dust seal 8a and the lower end portion of the dust seal 8a.

That is, the axial length is set larger than that of the conventional protector guide 18 shown in FIGS. 4 and 5, and the large protector guide 18a is formed so as to surround most of the dust seal 20a.

The lower end of the protector guide 18a is bent inward to have a bent portion 22.

On the other hand, an annular projection 2 having an outer diameter approximately equal to the inner diameter of the protector guide 18a is provided on the outer periphery of the dust seal 20a.
1 is integrally molded. When installing the dust seal 20a, the dust seal 20a is first fitted into the lower end opening of the outer tube 10, and then the protector guide 18a is moved upward in FIG. 2 and fixed. At this time, the annular projection 21 of the dust seal 20a is connected to the lower end of the outer tube 10 and the curved portion 22 of the protector guide 18a.
The dust seal 20a is firmly held and fixed inside the protector guide 18a.

According to the front fork for a motorcycle according to this embodiment, the protector guide 18a is formed larger than the conventional one so as to surround most of the outer periphery of the dust seal 20a, and the dust seal 20a is attached to the protector guide 18a.
It has a protective function.

Therefore, when the motorcycle is running, flying objects such as flying stones are less likely to directly collide with the dust seal 20a. Therefore, the risk of damage to the oil seal 19 or loss of function of the front fork due to damage or falling off of the dust seal 20a is largely eliminated.

In addition, the lower end of the outer tube 10 and the protector guide 18
Since the annular protrusion 21 formed integrally with the dust seal 20a is firmly clamped and fixed by the curved portion 22 formed at the lower end of the dust seal 20a, there is almost no possibility that the dust seal 20a will fall off from the outer tube 10. Furthermore, the function of preventing the dust seal 20a from falling off is sufficiently ensured by the holding of the annular protrusion 21, so that the dust seal 20a
There is no need to set a long distance for press-fitting a into the outer tube 10. Therefore, dust seal 2 during maintenance
This makes it easy to remove and install the Oa, reducing the workload of maintenance personnel and significantly increasing work efficiency.

〔Effect of the invention〕

As explained above, according to the front fork for a motorcycle according to the present invention, since the protector guide is formed in a large size so as to surround the outer periphery of the dust seal, flying objects such as flying stones collide directly with the dust seal. There will be fewer things. Therefore, it is possible to effectively prevent the dust seal from being damaged or falling off.

Further, since a structure is adopted in which the outer peripheral portion of the dust seal is held between the lower end of the outer tube and the protector guide, it is possible to prevent the dust seal from falling off from the outer tube. Furthermore, since the press-fitting distance for the dust seal into the outer tube can be shortened, the dust seal can be easily removed and installed during maintenance, and the efficiency of maintenance work can be greatly improved.

[Brief explanation of drawings]

1A and 1B are a side view and a front view, respectively, showing an embodiment of a motorcycle front fork according to the present invention, and FIG. 2 is a partial sectional view showing the structure of the dust seal part in FIG. Figure 3 (A). (B) is a side view and a front view showing a configuration example of a motorcycle to which the present invention is applied, FIG. 4 is a side view showing the external shape of a conventional front fork, and FIG. FIG. 3 is a partial cross-sectional view showing the structure. 1...Vehicle frame, 2...Front fork, 3
...Front wheel, 4...Swing arm, 5...Rear wheel,
6...Engine, 7...Fuel tank, 8...
・Seat, 9... Handle, 10... Outer tube, 11... Inner tube, 12... Upper bracket, 13... Under bracket, 14... Front axle bracket, 15... Front Axle, 16... protector device, 17... protector,
18, 18a... Protector guide, 19... Oil seal, 20, 20a... Dust seal, 21...
- Annular projection, 22... curved part.

Claims (1)

[Claims] An inner tube supported by the front wheel, an outer tube that telescopically accommodates the inner tube, a dust seal attached to the lower end of the outer tube to prevent dust from entering the outer tube, and an inner tube attached to the lower end of the outer tube to prevent dust from entering the outer tube. In a front fork for a motorcycle equipped with a protector guide that fixes a protector that protects a tube, the protector guide is formed to surround the outer periphery of the dust seal, and the lower end of the outer tube and the protector guide protect the dust seal. A front fork for a motorcycle that is characterized by a sandwiched outer periphery.