JPH0550971A - Rear fork for motorcycle - Google Patents

Abstract

PURPOSE:To provide rear fork for a motorcycle, which is so constituted that a cross member is formed out of extruded hollow material with welding areas lessened while being possible to be inexpensive as a whole because its molding is inexpensive and its weight is light. CONSTITUTION:Both the end faces of a cross member 1 made of a light alloy are interposed between a right and a left rear fork 4 at their front sections so as to be welded wherein the cross member is so constituted that it is molded by means of extrusion or pultrusion, its inner side is made hollow, reinforcing surfaces 2 are formed at its end faces, and a boss having a shaft hole 3 which rotatably attaches a cushion link at its one side, is integrally formed therein. A shaft cylinder 6 is interposed between the right and left rear forks so as to be welded, and each axle fitting 5 is welded to the rear ends of the rear fork.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear fork of a motorcycle for suspending rear wheels.

[0002]

2. Description of the Related Art A motorcycle has been improved in vehicle performance by reducing the weight of a vehicle body, and a frame and a rear hawk are made lightweight by using a light alloy.

When the rear fork is made of light alloy, as shown in FIG. 6, the front ends of the left and right rear forks A of the light alloy pipe are welded to the barrel B of the light alloy pipe, and the cushion links are pivotally mounted. A light or heavy alloy cross member D having a shaft hole C is welded to the front portions of the left and right rear forks A.

Further, as shown in FIG. 7, the left and right rear forks H of the light alloy pipe are formed integrally with the front cylinder F and the shaft hole G in the light alloy at both rear ends of the cross member E. Some are welded.

Further, as shown in FIG. 8, the front portions of the left and right rear forks H are welded to both sides of the cross member J of the drawing material which is hollow in the lateral direction, and the front and rear ends of the left and right rear forks K are attached to the tubular member. There is also one in which M is welded and a support stay N having an axial hole is welded to the cross member J. See, for example, JP-A-59-29581.

[0006]

When the cross member is made by casting or forging, there is a disadvantage that the production die becomes expensive. Especially, in the case of a cast product, the material is unneeded, so the wall thickness should be increased. Therefore, there is a disadvantage that it becomes heavy and heavy. Further, in the case of FIG. 8, there are many welding parts, and there is a disadvantage that the welding work becomes complicated.

In view of the above point, the present invention provides a rear fork of a motorcycle which can be manufactured inexpensively as a whole by forming the cross member with a hollow extruded material, which can be manufactured at a low cost and can be made lightweight. The purpose is to get.

[0008]

In order to achieve the above object, the rear fork of the motorcycle of the present invention is extruded or pultruded to form a hollow inside and form a reinforcement reinforcement surface on both end faces. At the same time, the above-mentioned both end surfaces of a cross member made of a light alloy integrally formed with a boss having a shaft hole for pivotally mounting a cushion link on one side are welded between the front parts of the left and right rear forks, and the front ends of the left and right rear forks. A shaft cylinder between
Axle metal fittings were welded to the rear end.

[0009]

Since the cross member is an extruded or pultruded product similar to the pipe material, the molding die is inexpensive, and the material can be made dense like the pipe material, and the wall thickness can be made thin and lightweight. Further, since the boss having the shaft hole for axially mounting the cushion link is integrally formed on one side of the cross member, the number of welded parts is small, the number of parts is small, and the cost can be reduced.

[0010]

Embodiments of the present invention will be described below with reference to FIGS. The cross member 1 is extruded or pultruded from a light alloy, has a hollow inside, forms reinforcing reinforce faces 2 on both end faces, and has a shaft hole for axially mounting a cushion link 9 on one side (lower side). A boss having 3 is integrally formed. The left and right rear forks 4 are light alloy pipes having a rectangular cross section, and an axle fitting 5 is inserted and welded to the rear ends thereof. Further, the front ends of the left and right rear forks 4 are welded to both side portions of the barrel 6 of the light alloy pipe. The cross member 1 is cut out in a U-shape in the front and rear of the center (see FIG. 4), and each end surface (including the reinforcing reinforcement surface 2) is welded to the front inner surface of the left and right rear forks 4.

In the rear fork 4, a shaft cylinder 6 at the front end is laterally axially attached to a lower portion of a frame 7 so as to be swingably mounted, and one end of a cushion link 9 of a cushion unit 8 is attached to a shaft hole 3 of a cross member 1. Pivot on. Then, the axle 11 having the rear wheel 10 rotatably attached is fastened to the left and right axle fittings 5 at the rear end of the rear fork 4. The rear fork 4 can expand and contract the cushion unit 8 to swing around the shaft cylinder 6, and
Cushion 0.

[0012]

As described above, according to the present invention, the cross member is an extruded or pultruded product having an integrated boss having an axial hole for axially mounting the cushion link.
It is possible to reduce the cost of the mold and to reduce the weight,
The number of welding points is small and the number of parts is also small, so that the cost can be reduced. Further, since the cross member has a body shape having a reinforcement surface for reinforcement, a sufficient welding length with respect to the rear fork is obtained, and the strength is increased.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a side view showing an embodiment of the present invention.

FIG. 3 is an enlarged side view of a cross member showing an embodiment of the present invention.

FIG. 4 is a perspective view of a cross member showing an embodiment of the present invention.

FIG. 5 is a side view of the entire vehicle body showing an embodiment of the present invention.

FIG. 6 is a perspective view showing a conventional example.

FIG. 7 is a perspective view showing another conventional example.

FIG. 8 is a perspective view showing still another conventional example.

[Explanation of symbols]

 1 Cross Member 2 Reinforcement Surface for Reinforcement 3 Shaft Hole 4 Rear Hawk 5 Axle Bracket 6 Shaft Cylinder 7 Frame 9 Cushion Link

Claims (1)

[Claims] 1. A light body which is extruded or drawn and has a hollow inside, has reinforcing reinforcement surfaces on both end surfaces, and integrally has a boss having a shaft hole for axially mounting a cushion link on one side. Both end faces of the cross member made of alloy are welded between the front parts of the left and right rear forks, and the axle cylinder is welded between the front ends of the left and right rear forks, and the axle metal fittings are welded at the rear ends. Hawk after the motorcycle to do.