JP3044737B2 - Front fork for motorcycle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a front fork for a motorcycle, and in particular, can prevent a dust seal from falling off or damaged, and can easily perform an operation of attaching and detaching a dust seal. The present invention relates to a front fork for a motorcycle, which is capable of driving.

(Prior Art) Generally, a motorcycle is configured as shown in FIGS. 3 (A) and 3 (B). That is, a front fork 2 is provided in front of the body frame 1, and the front wheel 3 is supported by the front fork 2. A rear wheel 5 is supported at the other end of a swing arm 4 whose one end is pivotally supported at the lower front part of the body frame 1, and this rear wheel 5 is buffered by a rear cushion unit (not shown). Furthermore, the body frame 1
An engine 6 is arranged at the lower center of the vehicle, and a fuel tank 7 and a seat 8 are installed above the vehicle body frame 1. The rider straddles the seat 8 and steers the steering wheel 9 to drive the motorcycle.

Incidentally, the front fork 2 is an inverted front fork, and an inner tube is provided in the outer tube 10.
An outer tube 10 is provided with an oil damper (not shown). The outer tube 10 includes an upper bracket 12, an under bracket 13, and a steering shaft (not shown).
, And is rotatably supported by the vehicle body frame 1 in the horizontal direction. A front axle bracket 14 is fixed to the lower end of the inner tube 11 as shown in FIG.
Front axle 15 is pivotally supported. The front fork 2 composed of the outer tube 10 and the inner tube 11 absorbs a shock from the front wheel 3 and attenuates vibration.

By the way, in the inverted front fork 2 as described above,
Since the inner tube 11 is disposed below the front part of the vehicle body, a protector device 16 is provided to protect the inner tube 11 from flying stones or the like flying from the front of the vehicle. As shown in FIGS. 3 (A) and (B) and FIG. 4, the 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. And 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 by bolts, while the lower end of the protector 17 is attached to the front axle bracket 14 by bolts or screws. Fixed. Therefore, when the front fork 2 expands and contracts telescopically, the protector
The upper end of 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, the protector 17 effectively protects the inner tube 11 from flying stones and the like.

On the other hand, as shown in FIG. 5, the outer tube 10 is used to reduce the impact of the inner tube 11 which reciprocates in the axial direction.
Is provided with an oil damper (not shown).
An oil seal 19 is provided between the outer tube 10 and the inner tube 11 to prevent the oil filled in the outer tube 10 from leaking outside. A dust seal 20 is provided on the inner periphery of the lower end opening of the outer tube 10 in order to prevent mud or dust adhering to the outer surface of the inner tube 11 from entering the oil seal 19 due to the reciprocation of the inner tube 11. Fitted.

(Problems to be Solved by the Invention) However, in the motorcycle front fork having the above-described configuration, mud and dust easily accumulate on the upper surface of the front axle bracket and the inner tube surface. When the inner tube is reciprocated, the dust seal may be damaged by external force due to dust or the like, or may fall off the outer tube. Further, when the motorcycle is run with the dust seal removed, the oil seal is also easily broken, and the oil for the oil damper leaks, and the function of the front fork is likely to be lost.

In particular, since the conventional dust seal is mounted with most of the dust seal exposed to the outside, it has a drawback that the dust seal is liable to be directly hit by a stepping stone or the like to be damaged or fall off.

On the other hand, in order to prevent the dust seal from falling off, a structure in which the press-fit margin l of the dust seal into the outer tube is set large as shown in FIG. By setting the press-fitting margin 1 large in this way, the detachment of the dust seal can be effectively prevented to some extent,
Conversely, during maintenance, it becomes difficult to remove the dust seal, and there is a problem that the working efficiency is reduced.

The present invention has been made in order to solve the above problems, and an object of the present invention is to provide a motorcycle front fork that can effectively prevent a dust seal from falling off or damaged and can easily perform a detaching operation. I do.

[Configuration 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 for accommodating the inner tube in a telescopic state, and an outer tube fitted to a lower end inner periphery of the outer tube. In a motorcycle front fork having a dust seal for preventing dust from entering the inside of the tube and a protector guide attached to the outer periphery of the lower end of the outer tube and slidably holding a protector for protecting the inner tube, The protector guide was formed so as to surround the outer peripheral portion of the dust seal, and the outer peripheral portion of the dust seal was sandwiched between the lower surface of the lower end of the outer tube and the curved portion extending in the inner circumferential direction formed at the lower end of the protector guide. It is characterized by the following.

(Operation) According to the motorcycle front fork according to the above configuration, since the protector guide is formed large so as to surround the outer peripheral portion of the dust seal, flying objects such as flying stones directly collide with the dust seal. Is reduced. Therefore, breakage and detachment of the dust seal can be effectively prevented.

In addition, because the lower end of the outer tube and the bent portion extending in the inner circumferential direction formed at the lower end of the protector guide sandwich the outer periphery of the dust seal,
The dust seal can be prevented from dropping from the outer tube. Further, since the press-fit allowance of the dust seal into the outer tube can be shortened, the dust seal can be easily removed and attached at the time of maintenance, and the work efficiency of the maintenance can be greatly increased.

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

1 (A) and 1 (B) 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 a structure of a dust seal portion. . The same elements as those in the conventional example shown in FIGS. 3 (A), (B), FIGS. 4 and 5 are denoted by the same reference numerals, and redundant description will be omitted.

That is, the motorcycle front fork according to the present embodiment includes an inner tube 11 supported on the front wheel 3 via a front axle bracket 14, an outer tube 10 that accommodates the inner tube 11 in a telescopic manner, and a lower end portion of the outer tube 10. A dust seal 20a mounted on the outer tube 10 to prevent dust from entering the inside of the outer tube 10,
A motorcycle front fork including a protector guide 18a slidably holding a protector 17 for protecting the inner tube 11 and attached to an outer periphery of a lower end portion of the outer tube 10 so as to surround the outer periphery of the dust seal 20a. Form protector guide 18a on the
The lower surface of the lower end of the outer tube 10 and the protector guide 18
The outer peripheral portion of the dust seal 20a is sandwiched between the lower end portion a and the lower end portion a.

That is, the length in the axial direction 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 and has a bent portion 22.

On the other hand, an annular projection 21 having an outer diameter substantially equal to the inner diameter of the protector guide 18a is integrally formed on the outer peripheral portion of the dust seal 20a. When installing the dust seal 20a, first attach the dust seal 20a to the outer tube 10
Fit the inner circumference of the lower end opening of the
a is moved and fixed in FIG. At this time, the annular projection 21 of the dust seal 20a is sandwiched between the lower surface of the lower end of the outer tube 10 and the bent portion 22 of the protector guide 18a, and the dust seal 20a is firmly held and fixed inside the protector guide 18a.

According to such a motorcycle front fork according to the present embodiment, the protector guide 18a is formed larger than before so as to surround most of the outer peripheral portion of the dust seal 20a, and the protector guide 18a has a protection function of the dust seal 20a. Have.

Therefore, flying objects such as flying stones do not directly collide with the dust seal 20a when the motorcycle is running. Therefore, the risk of damaging the oil seal 19 and losing the function of the front fork due to breakage or detachment of the dust seal 20a is almost eliminated.

Further, the annular projection 21 formed integrally with the dust seal 20a is firmly nipped and fixed by the lower surface of the lower end of the outer tube 10 and the bent portion 22 formed at the lower end of the protector guide 18a.
There is almost no risk of falling off. Further, the function of preventing the dust seal 20a from falling off is sufficiently ensured by the holding of the annular projection 21, so that it is not necessary to set a long press-fitting margin of the dust seal 20a into the outer tube 10.
Therefore, it is easy to remove and attach the dust seal 20a at the time of maintenance, so that the work load of the maintenance staff can be reduced and the work efficiency can be greatly increased.

〔The invention's effect〕

As described above, according to the motorcycle front fork according to the present invention, since the protector guide is formed large so as to surround the outer peripheral portion of the dust seal, flying objects such as flying stones directly collide with the dust seal. Less. Therefore, breakage and detachment of the dust seal can be effectively prevented.

In addition, since the outer peripheral portion of the dust seal is sandwiched between the lower surface of the lower end of the outer tube and the bent portion formed on the inner periphery of the lower end of the protector guide, the dust seal can be prevented from falling off from the outer tube.
Furthermore, since the press-fitting margin of the dust seal into the outer tube can be shortened, the dust seal can be easily removed and mounted at the time of maintenance, and the efficiency of the maintenance work can be greatly increased.

[Brief description of the drawings]

1 (A) and 1 (B) are a side view and a front view, respectively, showing an embodiment of a motorcycle front fork according to the present invention, FIG. 2 is a partial sectional view showing a structure of a dust seal portion in FIG. 1, 3 (A) and 3 (B) are a side view and a front view, respectively, showing a configuration example of a motorcycle to which the present invention is applied, FIG. 4 is a side view showing an external shape of a conventional front fork, and FIG. It is a fragmentary sectional view showing the structure of the dust seal part of the front fork. 1 ... body 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 protrusion, 22 ...
Composition department.

Claims (1)

(57) [Claims] An inner tube supported by a front wheel, an outer tube for housing the inner tube in a telescopic manner, a dust seal fitted to an inner periphery of a lower end portion of the outer tube to prevent dust from entering the inside of the outer tube, A protector guide is formed to surround the outer periphery of the dust seal in a motorcycle front fork having a protector guide mounted on the outer periphery of the lower end of the outer tube and slidably holding a protector for protecting the inner tube. A front fork for a motorcycle, wherein an outer peripheral portion of the dust seal is sandwiched between a lower surface of a lower end portion of an outer tube and a curved portion extending in an inner peripheral direction formed at a lower end of a protector guide.