JPH04314683A - Swing arm for motorcycle - Google Patents

Abstract

PURPOSE:To obtain a swing arm for a motorcycle with a feeling of lightness by enabling weight to decrease while holding rigidity. CONSTITUTION:A shaft hole 1 for rotatably mounting selectively a cushion unit 8 and a link 9 thereof is protrusively provided in a rear part, a body 4 is provided with a pivot hole 3 in a point end of front part right/left arms 2, upper/lower surfaces of the right/left arms 2 of the body 4 are formed in a protrusive curved surface 10, a front end of an arm pipe 5 is mounted fused to right/left rear ends of the body 4, the right/left arm pipes 5 are formed with upper/lower surfaces in a recessed curved surface 11 by a long quadrangular section, so that respective axle metal fixtures 6 are inserted fused to rear ends of the right/left arm pipes 5.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a motorcycle swing arm for suspending a rear wheel.

0002

BACKGROUND OF THE INVENTION As shown in FIGS. 4 and 5, a motorcycle has a shaft hole 1 at the rear for which a cushion unit or a link of the cushion unit is pivoted, and an arm 2 that projects left and right forward. Pivot hole 3 at the tip of arm 2
A body 4 is provided, the front ends of arm pipes 5 are welded to the left and right rear ends of the body 4, swing arms with axle fittings 6 welded to the rear ends of the left and right arm pipes 5 are provided, and the pivot holes are connected to the lower part of the frame. A cushion unit or a link of the cushion unit is connected to the shaft hole 1, and an axle rotatably supporting a rear wheel is inserted into and fastened to the axle fitting 6 at the rear end. The swing arm expands and contracts the cushion unit and swings around the pivot hole 3 to cushion the rear wheel. In the swing arm, the cushion unit or the shaft hole 1 that connects the links of the cushion unit receives the largest load. Attach the upper and lower surfaces to the axle metal fittings 6
It is tapered and narrowed towards the rear where it connects. Ribs 7 are formed before and after the shaft hole 1. For example, see JP-A-63-71491.

0003

[Problem to be solved by the invention] The rear part of the body 4 and the front part of the arm pipe 5 are thickened, and the rib 7 is also added, making the entire swing arm solid and sturdy, giving it a nimble and lightweight feel. Run short.

[0004] In view of the above, an object of the present invention is to provide a swing arm for a motorcycle that can be lightened while maintaining rigidity and has a light feel.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the motorcycle swing arm of the present invention has a shaft hole protruding from the rear portion for selectively pivoting the cushion unit and the link of the cushion unit, and a shaft hole for selectively pivoting the cushion unit and the link of the cushion unit. The upper and lower surfaces of the left and right arms are formed into convex curved surfaces, and the front ends of the arm pipes are welded to the left and right rear ends of the body, and the left and right arm pipes have a cross-sectional length. It has a rectangular shape with concave curved top and bottom surfaces, and axle fittings are inserted and welded to the rear ends of the left and right arm pipes, respectively.

[0006]

[Function] Since the upper and lower surfaces of the left and right arms of the body are formed into convexly curved surfaces, the cross section can be made large, increasing the rigidity, and the ribs provided before and after the shaft hole can be made small. In addition, the left and right arm pipes are the most noticeable parts when attached to the frame, but since the upper and lower surfaces are formed into concave curved surfaces,
While maintaining the rigidity near the front shaft hole, it can be made slim and lightweight, giving it a light feel.

[0007]

Embodiments Hereinafter, embodiments of the present invention will be explained based on FIGS. 1 to 3. In FIG. 1, a shaft hole 1 is provided in the rear part of the shaft hole 1 so as to protrude upward, and the lower end of the cushion unit 8 or the link 9 of the cushion unit 8 is selectively pivotally connected thereto. Arms 2 that protrude forward on the left and right are integrally provided, and the arms 2
A body 4 having a pivot hole 3 formed at the tip thereof is provided. The body 4 is cast from a light alloy or the like, and the upper and lower surfaces of the arm 2 are formed into convex curved surfaces 10. Then, small ribs 7 are integrally formed before and after the shaft hole 1. Left and right arm pipes 5 are welded to both rear ends of the body 4. The arm pipe 5 is made of a pipe material such as a light alloy, has a vertically long rectangular cross section, and has a concave curved surface 11 on the top and bottom surfaces. An axle fitting 6 is inserted and welded to the rear ends of the left and right arm pipes 5 to form a swing arm.

The swing arm has a pivot hole 3 at the front end pivotally attached to the lower part of the frame 12, and a cushion unit 8 or a link 9 of the cushion unit 8 in the shaft hole 1.
Attach the shaft. Then, the axle 14 rotatably supporting the rear wheel 13 is inserted into the left and right axle fittings 6 and fastened. The cushion unit 8 is expanded and contracted, the swing arm swings around the pivot hole 3 at the front end, and the rear wheel 13 is cushioned. Note that the front end side surfaces of the left and right arm pipes 5 are provided with tongues 15 that extend forward toward the pivot hole 3 to prevent stress concentration due to welding.

[0009]

[Effects of the Invention] As explained above, since the present invention is constructed as described above, the rigidity can be increased by making the upper and lower surfaces of the left and right arms of the body of the swing arm into convex curved surfaces. The ribs before and after the shaft hole can be made smaller. Furthermore, by making the upper and lower surfaces of the left and right arm pipes concavely curved, they can be made thinner and lighter while maintaining rigidity near the shaft hole. The left and right arm pipes are the most noticeable parts when attached to the frame, and by making the upper and lower surfaces concavely curved, they can be made thin and light.

[Brief explanation of drawings]

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

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

FIG. 3 is an overall side view showing an embodiment of the present invention.

FIG. 4 is a side view showing a conventional example.

FIG. 5 is a plan view showing a conventional example.

[Explanation of symbols]

1 Shaft hole 2 Arm 3 Pivot hole 4 Body 5 Arm pipe 6 Axle metal fittings 8 Cushion unit 9 Link 10 Convex curved surface 11 Concave curved surface

Claims (1)

[Claims] Claim 1: The upper and lower surfaces of the left and right arms of a body that has shaft holes protruding from the rear for selectively pivoting the cushion unit and the links of the cushion unit, and pivot holes at the tips of the front left and right arms. is formed into a convex curved surface, the front ends of the arm pipes are welded to the left and right rear ends of the body, the left and right arm pipes are rectangular in cross section, and the upper and lower surfaces are formed into concave curved surfaces, and the rear ends of the left and right arm pipes are A motorcycle swing arm characterized in that each axle fitting is inserted and welded.