JPH09150771A - Front fork bracket structure of motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set the projection below an axle to be short, eliminate the labor in working an under bracket, reduce the number of part, items and save the cost. SOLUTION: In a front fork bracket structure A of a motorcycle, a base plate 19 to be used as a number plate is provided on a head pipe 4h, and a shaft supporting part 21 to support a base part of a steering shaft 5s to be internally fitted to the head pipe 4h at the center in the width direction in a lower part of a back side, and a pair of right and left inner tube supporting parts 23 which are located in a deviated manner in the upward direction on the right and left sides of the shaft supporting part and support a part of an upper part of the inner tube 15 in a fixed condition are integrated with each other on a back surface 19r of the base plate 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front fork bracket structure for a motorcycle. More specifically, the structure relates to an under bracket which is a component of a front fork of a motorcycle called a telescopic type in which an inner tube and an outer tube slide and expand and contract.

[0002]

2. Description of the Related Art A front fork is a rigid member of which a unit itself constitutes a steering wheel, supports front wheels, and transmits steering force by steering operation to the front wheels. FIGS. 6 and 7 partially show an example of a motorcycle that employs a conventional front fork. The figure shows an enlarged perspective view of the front part of the vehicle, and FIG. 7 shows only the front fork shown in FIG. It is an enlarged front view showing.

A front fork called a telescopic type is adopted for an off-road motorcycle. In the telescopic fork, the inner tube and the outer tube slide and expand and contract,
This provides a cushioning function as a front suspension.

The telescopic forks include an upright type in which the inner tube is located above and the outer tube is located below, and an inverted type in which the outer tube is located above and the inner tube is located below. Here, an upright front fork is shown.

More specifically, as shown in FIGS. 6 and 7, an upright front fork a has an upper bracket and an under bracket which are rotatably provided at the upper and lower ends of a head pipe b at the front of a vehicle body frame. A pair of inner tubes e fixedly attached to the left and right sides of c and d respectively, and a pair of inner tubes e located outside of the inner tubes e in a fitted state and having elasticity in relation to the pair of inner tubes e. In this state, the outer tube f is configured to move up and down with respect to the inner tube e to expand and contract the entire length of the fork. A shaft support piece g that supports a front axle (not shown) is provided below each outer tube f.

[0006] By the way, in an off-road motorcycle that runs around the mountains, it is necessary to secure a large damper stroke between the inner tube and the outer tube. Also,
An off-road bike may run in a depression, and in that case, in order to prevent the lower part of the outer tube from coming into contact with the slope of the depression as much as possible, a shaft support piece g for supporting the front axle and a lower end of the outer tube. It is necessary to make the length between f ₁ and the so-called axle downward protrusion L (see FIG. 7) as short as possible.

Therefore, the under bracket d is channel-shaped, in other words, the central portion of the under bracket is located below both ends, and the central portion d of the under bracket d is located.
There is a case where ₁ and both end portions d ₂ are connected by a beveled intermediate portion d ₃ . However, if the under bracket d is formed in a channel shape in this way, the processing becomes laborious.

Therefore, it has been desired to provide a technique capable of shortening the amount of protrusion of the lower portion of the axle without spending time and labor on the processing of the under bracket.

Further, a dedicated motorcycle designed or manufactured or modified for a motorcycle competition is called a racing machine, and road races, motocross and trials are famous as competitions currently being conducted. And among the machines used for these competitions, the machines for motocrossers and trialers are equipped with a number plate instead of the headlights at the location where the headlights of the on-road bike are installed. .

On the other hand, in recent years, the price breakage has been extended to motorcycles, and there has been a demand for reducing the number of parts to save costs.

[0011]

SUMMARY OF THE INVENTION The present invention has been invented in view of the above circumstances, and the problem to be solved is to set a lower amount of thrust of the axle short and to process an under bracket. It is an object of the present invention to provide a front fork bracket structure for a motorcycle that saves labor by reducing the number of parts and cost.

[0012]

The present inventor has taken the following means in order to solve the above problems. That is, the front fork bracket structure of the motorcycle of the present invention is provided on the upper and lower ends of the head pipe located at the front end of the vehicle body frame, and is rotated with respect to the head pipe through the steering shaft fitted in the head pipe. A pair of inner tubes fixed to the left and right sides of the movable upper and lower brackets, respectively, and externally fitted to the lower parts of the pair of inner tubes, and have elasticity in relation to the pair of inner tubes. In this state, in an upright front fork consisting of an outer tube that can be elastically displaced in the axial direction with respect to the inner tube, a substrate used as a number plate is provided on the front side of the head pipe. On the back surface of the substrate, the head pipe is provided at the center in the width direction in the lower part of the back surface. A shaft support part that supports the base part of the steering shaft to be fitted, and a state in which the shaft support part is located on the left and right sides of the shaft support and is displaced upward from the shaft support part, and a part of the upper part of each inner tube is fixed. A pair of left and right inner tube support portions supported by the integrally formed molding, the shaft support portion, the pair of inner tube support portions, and a portion of the substrate located between the shaft support portion, substantially as the under bracket Formed a working under bracket assembly.

Therefore, according to the front fork bracket structure of the motorcycle of the present invention, the base plate used as the number plate, the shaft support portion, and the inner tube support portion are integrally formed, and
Since the shaft support portion, the inner tube support portion, and the portion of the substrate located between them form an under bracket assembly that substantially functions as an under bracket, the bib plate and the under bracket are substantially integrally molded. It can be said that Therefore, the number of parts can be reduced by one as compared with the case where they are assembled separately. Therefore, the number plate and the under bracket can be processed at the same time, which saves labor and saves costs.

Further, on the back surface of the substrate, a shaft supporting portion for supporting the base portion of the steering shaft fitted in the head pipe is provided at the center of the lower portion in the width direction, and on the left and right sides of the shaft supporting portion. With a pair of left and right inner tube supporting portions positioned in a state of being displaced in an upward direction with respect to the shaft supporting portion, and with a part of the substrate positioned between the shaft supporting portion and the pair of left and right inner tube supporting portions, The under bracket functions substantially as a channel, in other words, it functions as an under bracket in which the center is located below both ends. Therefore, the amount of lowering of the axle can be set short.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail based on the illustrated embodiments with reference to the drawings. 1 is an overall side view of a motorcycle 1 adopting a front fork bracket structure A for a motorcycle according to the present invention, FIG. 2 is an enlarged perspective view of an essential part of FIG. 1, FIG. 3 is a rear view of FIG. 3 is a sectional view taken along the line IV-IV of FIG. 3 and seen in the direction of the arrow, and FIG. 5 is a sectional view taken along the line V-V of FIG. 3 and seen in the direction of the arrow. is there.

The handlebar 3 of the motorcycle 1 includes a steering stem 5 that rotates left and right with respect to a head pipe 4h located at the front end of a vehicle body frame 4, and an upright front fork 6 attached to the steering stem 5. The front wheels 7 are pivotally steered left and right via (hereinafter, simply referred to as "fork 6").

The steering stem 5 is a head pipe 4.
Steering shaft 5s fitted inside h (see FIG. 3)
And an upper bracket 9 fixedly provided on the upper and lower sides of the steering shaft 5s so as to be separated from each other, and an under bracket assembly 11 which corresponds to a normal under bracket and will be described in detail later. Therefore, the upper bracket 9 and the under bracket assembly 11 are rotatable with respect to the head pipe 4h via the steering shaft 5s.

Further, on the left and right sides of the upper bracket 9 and the under bracket assembly 11, upper parts of a pair of left and right inner tubes 15, 15, which are constituent members of the fork 6 for rotatably supporting the front wheel, are fixed. The other part of the fork 6 is provided below the pair of inner tubes 15, 15.
The outer tube 1 which is externally fitted to the inner tube 15 and has elasticity in relation to the inner tube 15 and is elastically displaceable in the axial direction with respect to the inner tube 15 in this state.
7 and 17 (only the outer tube on the left side is shown in FIG. 1) are arranged.

The front side of the head pipe 4h, more specifically, the upper bracket 9, the under bracket assembly 11, and the inner tube 15 located between the upper bracket 9 and the under bracket assembly 11.
In a substantially rectangular area on the front side of the vehicle, which is surrounded by the upper portions 15u and 15u of 15, a substrate 19 to be described below, which is used as a number plate, is provided.

On the back surface 19r of the substrate 19, there is provided a shaft support portion 21 for supporting the base portion (lower end portion) of the steering shaft 5s fitted in the head pipe 4h at the center in the width direction at the lower portion thereof. Similarly, on the back surface 19r of the base plate 19 on the left and right sides of the shaft support portion 21 and at positions displaced upward from the shaft support portion 21, right and left portions that support a part of the upper portion 15u of each inner tube 15 in a fixed state. A pair of inner tube support portions 23, 23 are provided, and the substrate 19, the shaft support portion 21, and the inner tube support portions 23, 23 are integrally molded. Each inner tube support portion 23 is the inner tube 1
5 is located below the upper part 15u.

In this embodiment, two inner tube support portions 23 are spaced apart from the upper portion of each inner tube 15, that is, two inner tube support portions 23 are located on the upper end portion side below the upper bracket 9 of the inner tube 15. The upper inner tube support portion 23u and the lower inner tube support portion 23d located below the upper inner tube support portion 23u. In addition, the number of each inner tube supporting body forming the inner tube supporting portion 23 is not limited to two, and may be three or more. Further, if there is no problem in strength, one may be used.

The shaft support portion 21, the pair of inner tube support portions 23, 23, and the portion 19p of the substrate 19 located between the shaft support portion 21 and the shaft support portion 21 constitute the under bracket assembly 11 having a function as an under bracket.

The under bracket assembly 11 includes a part 1
Although various forms can be considered depending on how to set 9p, for example, the lower inner tube support portion 23d, the shaft support portion 21, and a part of the substrate located between the two connecting the two 23d and 21 (two points in FIG. 3). (Slope part indicated by chain line) 1
If 9p is considered as an integral body and this is regarded as a virtual under bracket, its shape is exactly as described in the prior art.
The center bracket is a channel-shaped under bracket located below both ends.

The upper inner tube support portion 23u
The same type of configuration can be obtained by the shaft support portion 21 and a part (no reference numeral) of the substrate located between the shaft support portion 21 and the two connecting the two portions 23u. In addition, the same applies to the inner tube support portion 23 including the upper and lower inner tube support portions 23u and 23d, the shaft support portion 21, and a portion (no reference numeral) of the substrate located between the two connecting the both 23 and 21. Can be said. These upper and lower inner tube support portions 23u and 23d are in the form of a clamp that detachably tightens the inner tube 15 with bolts 24. It should be noted that what is indicated by the symbol L in FIG. 1 is the amount of protrusion of the axle downward.

The above structure will be referred to as a front fork bracket structure A for a motorcycle according to the present invention.

According to the front fork bracket structure A for a motorcycle thus constructed, the base plate 19, which is used as the number plate, the shaft support portion 21, and the inner tube support portion 23 are integrally molded. And the shaft support portion 21 and the lower inner tube support portions 23d and 23d, and the portions 19p and 19p of the board 19 located between these portions 21 and 23d and 21 and 23d, respectively, function as an under bracket. Since the under bracket assembly 11 is provided, the bib plate and the under bracket are substantially integrally molded. Therefore, the number of parts can be reduced by one as compared with the case where they are assembled separately. Therefore, the number plate and the under bracket can be processed at the same time, which saves labor and saves costs.

Further, on the back surface 19r of the substrate 19, a shaft support portion 21 for supporting the base portion of the steering shaft 5s fitted in the head pipe 4h is provided at the center in the width direction at the lower portion thereof, and the shaft support portion 21 is provided. A pair of left and right lower inner tube support portions 23d.2 positioned on the left right side in a state of being displaced upward from the shaft support portion 21.
3d is provided, and the portions 19p and 19p of the substrate located between the shaft support portion 21 and the pair of left and right lower inner tube support portions 23d and 23d are channel-shaped, in other words, the center is located below both ends. Since it can be made to function as the under bracket assembly 11 having the form described above, the amount of downward protrusion L of the axle can be set short. It should be noted that by locating the lower inner tube support portions 23d and 23d further upward, the lower thrust amount L of the axle can be set even shorter.

[0028]

According to the present invention, the amount of protrusion of the lower portion of the axle can be set to be short, the underbracket can be processed without trouble, and the number of parts can be reduced to save the cost.

[Brief description of the drawings]

FIG. 1 is an overall side view of a motorcycle that employs a front fork bracket structure for a motorcycle according to the present invention.

FIG. 2 is an enlarged perspective view of a main part of FIG.

FIG. 3 is a rear view of FIG. 2;

4 is a sectional view taken along a line IV-IV in FIG. 3 taken along a virtual cutting plane and viewed in the direction of the arrow.

5 is a cross-sectional view taken along a virtual cutting plane including line VV of FIG. 3 and viewed in the direction of the arrow.

FIG. 6 is a diagram for explaining a conventional technique.

FIG. 7 is a front view of FIG. 6;

[Explanation of symbols]

A Front fork bracket structure of motorcycle 4 Body frame 4h Head pipe 5s Steering shaft 6 Upright front fork 9 Upper bracket 11 Under bracket assembly (under bracket) 15 Inner tube 17 Outer tube 19 Substrate 19r Substrate backside 19p Substrate 21 Shaft support 23 Inner tube support

Claims (1)

[Claims] 1. An upper and an underbody which are respectively provided on upper and lower end sides of a head pipe located at a front end portion of a vehicle body frame and are rotatable with respect to the head pipe via a steering shaft fitted in the head pipe. A pair of inner tubes fixed to each of the left and right sides of the bracket, and externally fitted to the lower portions of the pair of inner tubes,
Having elasticity in relation to the pair of inner tubes,
In an upright front fork consisting of an outer tube that is elastically and movably displaced in the axial direction with respect to the inner tube in this state, a substrate used as a number plate is provided on the front side of the head pipe. Includes a shaft support portion that supports a base portion of the steering shaft that fits in the head pipe at the center in the width direction at a lower portion of the back surface, and on the left and right sides of the shaft support portion more than the shaft support portion. A pair of left and right inner tube support portions that are displaced upward and support a part of the upper portion of each inner tube in a fixed state are integrally provided, and the shaft support portion and the pair of inner tubes are provided. An under bracket that substantially functions as the under bracket by the supporting portion and the portion of the substrate located between the supporting portion and the supporting portion. Front fork bracket structure for a motorcycle, characterized in that the formation of the assembly.