JPH0740474Y2 - Motorcycle front fork - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a front fork of a motorcycle, and more particularly to a front fork having a gas-filled suspension structure.

[Conventional technology]

Generally, in the front fork of a motorcycle, gas (particularly inert gas) is enclosed in the inner tube to absorb the shock received from the road surface by the elasticity of both the coil spring and the sealed gas. There are some improvements.

In addition, in the past, especially in off-road vehicles whose main purpose is to drive on uneven terrain, in order to secure a larger suspension stroke of the front fork, a reserve tank for gas enclosed in the inner tube is provided separately from the inner tube. The reserve tank and the inner tube are connected by a separate gas pipe to ensure a large amount of gas sealed in the inner tube.

The gas reserve tank described above is formed separately from the components around the steering wheel, and is mounted so as to project on the upper bracket of the steering wheel that supports the inner tube.

[Problems to be solved by the device]

In the conventional front fork having the above-mentioned gas reserve tank, the inner tube of the front fork and the gas reserve tank are connected by a separate gas pipe, and the reserve tank projects above the steering upper bracket. Since it is attached, there is a problem that the pipe and the connecting portion of the pipe are easily damaged by the impact of a small stone or the like which is received when the vehicle falls or travels on an uneven terrain. Further, since a separate reserve tank, which is a heavy item, is attached to the upper bracket of the steering wheel, there is a problem that the lightness of steering operation is lost.

In order to solve the above-mentioned problems, the conventional method
As described in Japanese Patent No. 51-153951, a steering bracket supporting an inner tube is integrally formed with a gas reserve tank, and the steering bracket is provided with a gas passage communicating between the gas reserve tank and the inner tube. Although what has been done is also proposed, the one described in Japanese Utility Model Laid-Open No. 51-153951 discloses that the steering bracket in the direction orthogonal to the front fork forms a gas reserve tank.
Its capacity is limited to the length between the pair of front forks, which may make it difficult to secure a sufficient capacity of the gas reserve tank. Further, if the capacity of the gas reserve tank is forcibly increased, there is a possibility that the gas reserve tank swells greatly to the front and comes into contact with surrounding members.

In view of the above-mentioned circumstances, the present invention secures a sufficient capacity of the gas reserve tank without inflating it forward,
Moreover, it is an object of the present invention to provide a front fork for a motorcycle, in which damage to the front fork is removed as much as possible and the lightness of steering operation is improved as much as possible.

[Means and Actions for Solving the Problems]

In order to solve the above-mentioned problems, according to the present invention, a pair of upper and lower upper and lower steering brackets are vertically arranged with a predetermined gap, and are fitted and supported on respective central portions of the upper steering bracket and the lower steering bracket. A pair of left and right front forks including a steering shaft, an outer tube, and an inner tube that is fitted into the outer tube, wherein the pair of left and right inner chambers are fitted to the left and right of the upper steering bracket and the lower steering bracket, respectively. In a front fork of a motorcycle having a supported front fork, the front fork of the motorcycle is independently provided in the upper steering bracket on the left and right of the steering shaft and between the pair of left and right inner tubes. A pair of gas reserve tanks, which are integrally formed in the upper steering bracket, have a bottom portion formed in the axial direction of the inner tube, and have an opening on the upper surface of the upper steering bracket. A lid for sealing the opening of the recess, a gas reserve tank including a check valve provided on the upper surface of the lid, and the inside of the recess for communicating with each other. A gas passage formed in the upper steering bracket and the peripheral surface of the inner tube, and a cap arranged at the upper end of the inner tube to seal the upper end of the inner tube. It has a cap with a check valve to be enclosed, which allows a separate gas communication gas The gas reserve tank and the inner tube are communicated without using a pipe, and the recessed part that constitutes the gas reserve tank is formed so that its bottom portion is oriented in the axial direction of the inner tube. It is designed to have sufficient capacity without inflating it forward.

〔Example〕

Hereinafter, one embodiment of the front fork according to the present invention will be described in detail.

FIG. 2 is a side view of the front fork 1 according to the present invention.

In this front fork 1, an inner tube 3 which is inserted in an outer tube 2 and which is positioned first in the left and right is fitted and supported in the left and right of a pair of upper and lower steering brackets 5 and 6 which support a steering shaft 4 at the center. There is.

On the other hand, a gas reserve tank 7 for gas (inert gas) sealed in the inner tube 3 is formed in the upper steering bracket 5. Note that FIG. 3 is an enlarged top view of a main portion of FIG.

On the other hand, the gas reserve tank 7 is a cylindrical recess 5a formed integrally with the upper steering bracket 5 as shown in FIG. 1 which is a sectional view taken along the line AA of FIG.
Is formed in the axial direction of the inner tube 3 and has a recess 5a having an opening 5f on the upper surface of the upper steering bracket 5, and a lid 8 for sealing the opening 5f of the recess 5a.
It consists of and.

In FIG. 1, reference numeral 9 is an elastic thin film supported between the lid 8 and the inner periphery of the recess 5a. As will be described later, the lid 8 and the thin film 9 are different from the recess 5a. The gas (air) accumulator 10 that fulfills the function of is constituted.

Further, as shown in FIG. 4 which is a sectional view taken along the line BB of FIG. 1, an annular groove 5b and a hole 5c are provided in the upper steering bracket 5 for communicating between the recess 5a of the gas reserve tank 7 and the inner tube 3. , And a hole 3a radially formed on the peripheral surface of the inner tube 3 facing the annular groove 5b.

Therefore, according to the front fork 1 described above, as shown in FIG. 1, the recess 5a of the gas reserve tank 7 and the inside of the inner tube 3 communicate with each other through the hole 3a, the annular groove 5b, and the hole 5c. Become.

In FIG. 1, reference numeral 12 is an O-ring that seals between the inner tube 3 and the upper steering bracket 5, and 13 is a cap that is disposed on the upper end of the inner tube 3 and seals the upper end of the inner tube 3. This cap 13
A check valve 14 for sealing the gas inside the inner tube 3 is attached to this. A check valve 15 is also attached to the upper surface of the lid 8 that seals the recess 5a.

In order to fill the above-mentioned front fork 3 with gas (inert gas), as shown in FIG. 1, gas (inert gas) is passed through a check valve 14 attached to a cap 13 for sealing the upper end of the inner tube 3. Supply arrow D). Then, the gas sealed in the inner tube 3 is filled into the recess 5a of the gas reserve tank 7 through the inner tube 3 and the gas passage 11. In addition, when the suspension characteristic of the front fork 3 is adjusted by increasing or decreasing the pressurization amount or the filling amount of the gas filled in the inner tube 3, the accumulator 10 made of the thin film 9 is supplied with air through a check valve 15. Enclose (arrow E) and
As shown in the figure, the accumulator 10 occupying the recess 5a
Increase or decrease the volume of.

Needless to say, the above-described gas reserve tank 7 is integrally formed in the upper steering bracket 5 at a total of two places for each of the pair of left and right front forks 3.

Further, in the above embodiment, the accumulator 10 is interposed in the recess 5a forming the gas reserve tank 7, but the accumulator 10 is not always necessary in the present invention, and is excluded when the amount of gas enclosed is constant. You may do it.

[Effect of device]

As described above, in the front fork of the present invention, the gas reserve tank is formed integrally with the upper steering bracket, and the upper steering bracket is formed with the gas passage communicating with the inner tube. It is possible to remove as much as possible the damage of the gas passage that connects the gas reserve tank and the inner tube due to the impact of pebbles, etc. when traveling on rough terrain, and the gas reserve tank is formed integrally with the upper steering bracket. Therefore, the weight is reduced,
The lightness of steering operation can be improved, the number of parts can be reduced, and the manufacturing cost of the front fork can be reduced. Further, in this invention, since the concave portion constituting the gas reserve tank is formed so that the bottom portion thereof faces the axial direction of the inner tube, the gas reserve tank is not inflated to the front side and its capacity is sufficiently ensured. It is possible to provide a front fork with good suspension characteristics suitable for the intended motorcycle, and moreover, the inner tube and the check valve for filling the gas in the gas reserve tank are all placed on the upper steering bracket. Therefore, the gas filling work can be performed from the upper surface of the upper steering bracket, and the workability is improved.

[Brief description of drawings]

FIG. 1 is a sectional view taken along the line AA in FIG. 3, FIG. 2 is a conceptual side view of a front fork according to the present invention, FIG. 3 is an enlarged top view of an essential part of FIG. 2, and FIG. 4 is BB of FIG. FIG. 5 is a sectional view of a main part of the front fork showing the action of the accumulator. 1 ... Front fork, 2 ... Outer tube, 3
...... Inner tube, 3a, 5b, 5c ...... Gas passage, 4 ...
… Steering shaft, 5 …… Upper steering bracket, 5g …… Bottom, 5f …… Opening, 6 …… Lower steering bracket, 7 …… Gas reserve tank, 8…
… Lid, 13 …… Cap, 14, 15 …… Check valve.

Claims (1)

[Scope of utility model registration request] 1. A pair of upper and lower upper and lower steering brackets (5, 6) arranged vertically at a predetermined distance.
A steering shaft (4) fitted and supported at the center of each of the upper steering bracket (5) and the lower steering bracket (6), an outer tube (2) and an inner tube fitted into the outer tube (2). Left and right front forks (1) consisting of 3)
In a front fork of a motorcycle, a pair of left and right inner tubes (3) have front forks (1) fitted and supported on the left and right sides of the upper steering bracket (5) and the lower steering bracket (6), respectively. , A pair of gas reserve tanks independently formed in the upper steering bracket (5) located on the left and right of the steering shaft (4) and between the pair of left and right inner tubes (3, 3). 7), which is integrally formed in the upper steering bracket (5) and has a bottom portion (5g) formed in the axial direction of the inner tube (3), and of the upper steering bracket (5). The recess (5g) having the opening (5f) on the upper surface and the opening (5f) of the recess (5a) are sealed. Lid (8) and, said top upper surface disposed in the check valve (8) (15) consisting of a gas reserve tank (7)
And a gas passage (3a) formed in the upper steering bracket (5) and the peripheral surface of the inner tube (3) so as to communicate between the inside of the recess (5a) and the inside of the inner tube (3). , 5b, 5c) and a cap (13) which is disposed on the upper end of the inner tube (3) and seals the upper end of the inner tube (3), and a gas is introduced into the inner tube (3) on the upper surface. Cap (1) with check valve (14)
3) A front fork for a motorcycle, characterized by including and.