JPH06234385A - Strength member for motorcycle - Google Patents

Abstract

PURPOSE:To prevent the generation of deformation to a machined part and improve machinability at the time of using a rectangular pipe as a strength member used for the frame or the like of a motorcycle. CONSTITUTION:The wall thickness dimension t1 of at least two angular parts 3a of a rectangular pipe is formed to be larger than the wall thickness dimension t0 of plane parts 3b. The wall thickness t1 part of the angular part 3a is extended onto the plane part 3b side, and the length L of the extended part is made larger than the wall thickness dimension t0 of the plane part 3b. The strength of the angular part 3a is thereby improved, so that deformation is not generated to the machined part, and machinability is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strength member for a motorcycle.

[0002]

2. Description of the Related Art A motorcycle is provided with many strength members such as a frame shown in FIG. The frame 1 of the strength members is usually assembled by bending the pipe material 2 as shown in FIG. 3 and welding various reinforcing materials to the pipe material 2. In the past, a round pipe was used as a frame pipe, but due to the problem of welding strength, a square pipe as shown in FIG. 4 has recently come into use.

The square pipe 3 may be an iron pipe, but a material such as an aluminum alloy or a resin may be used in order to reduce the weight. The cross-sectional shape is a quadrangle as shown in FIG. This is an attempt to improve the welding strength by utilizing the flat surface on one side of the quadrangle, but when the square pipe 3 is processed, there are the following problems, and their solution is an important issue. There is.

That is, the square pipe has poor workability and is not easy to work. Deformation strain 4 occurs on the inner surface of the bent portion (the portion A in FIG. 3 (see FIG. 5), which contributes to a decrease in the strength of the frame 1. Deformation or strain may deteriorate the appearance of the product. Is.

[0005]

DISCLOSURE OF THE INVENTION The present invention fundamentally solves the above-mentioned problems, and provides a strength member for a motorcycle, in which deformation of a machined portion does not occur, workability is improved and cost is reduced. The purpose is to

[0006]

As a means for solving the above-mentioned problems, the present invention provides a square pipe in which the thickness dimension of at least two corners of a square pipe is defined by a flat portion surrounded by the corners. In addition to being formed to be larger than the wall thickness dimension, a portion having a large wall thickness dimension of the corner portion is extended to the flat surface side, and the length of the portion having a large wall thickness dimension of the corner portion is made larger than the wall thickness dimension of the flat surface portion. It is configured.

[0007]

According to this structure, the thickness of the corner portion is larger than the thickness of the flat portion between the two corner portions, and the length of the corner portion having the larger thickness dimension is larger than that of the flat portion. By making it longer than the wall thickness dimension, the strength of the corner portion to which stress is applied during processing is improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. 1 and FIG. 2 showing an enlarged main part thereof. Reference numeral 3 denotes a square pipe in which the wall thickness dimension t ₁ of the corner portion 3a is larger than the wall thickness dimension t _{0 of the} flat surface portion 3b (side portion) surrounded by the corner portion 3a. One of the plane portions, indicated by reference numeral 3c, is thicker than the other plane portions 3b. And corner 3a
Of a portion having a wall thickness t _1, extending to the planar portion 3b side from the extension line Z of the inner wall of the other of the planar portion 3b, the length L of the extended portion, than the thickness dimension t ₀ of the flat portion 3b It's big.

As described above, the corner portion 3a of the square pipe 3 is replaced with the flat surface portion 3b.
The relative formed a thick, yet the wall thickness t ₁ of the corner 3a is increased relative to the wall thickness t ₀ of the flat portion 3b, and sets the length of the corner 3a as described above By this, the strength of the corner portion 3a with respect to the flat surface portion 3b is increased, so that the deformation and strain at the time of processing the square pipe 3 are reduced.
It is possible to prevent deformation when the square pipe 3 is used in a stressed part.

[0010]

As described above, according to the present invention, in a square pipe, at least two corner portions of the square pipe are formed to have a larger wall thickness dimension than a flat surface portion surrounded by the corner portions. The corner portion having a large wall thickness dimension is extended to the flat surface side, and the length of the corner portion having a large wall thickness dimension is made larger than the wall thickness dimension of the flat surface portion. Since the strength with respect to the flat portion of the square pipe is increased, the deformation and strain when the square pipe is processed is reduced, the workability is improved, and the cost can be reduced. In addition, it is possible to prevent deformation when the square pipe is used in a stressed portion.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view showing an enlarged main part of FIG.

FIG. 3 is a perspective view of a frame of a motorcycle as an example of a strength member.

4 is a cross-sectional view when the frame of FIG. 3 is a square pipe.

FIG. 5 is a cross-sectional view showing a state in which strain is generated during processing in FIG.

[Explanation of symbols]

 1 frame 3 square pipe 3a corner 3b plane

Claims (1)

[Claims] 1. In a square pipe, at least two corner portions of the square pipe are formed to have a wall thickness larger than a flat surface portion surrounded by the corner portion, and the wall thickness of the corner portion is large. A strength member for a motorcycle, wherein a portion is extended to the plane portion side, and a length of a corner portion having a large wall thickness dimension is made larger than a wall portion thickness dimension of the flat surface portion.