| 摘要 |
PURPOSE:To improve the extent of reliability from the standpoint of strength by forming a rear part or a front part of an arm body from a rear wheel suspension connecting part with a taper angular pipe forming a cylindrical blank pipe into a square shape by means of compression molding, in a rear arm consisting of connecting a symmetrical pair of arm bodies with a connecting member. CONSTITUTION:In a rear arm 16 which is pivotally supported on a rear end of a body frame of a motorcycle free of rocking motion up and down, an interval between intermediate parts of a symmetrical pair of arm bodies 26, 26 consisting of both front and rear arms 19, 18 is connected by a connecting pipe 19c, and an end piece 20 supporting an axle is fixed to the rear end of the arm body 26 by means of welding. Then, symmetrical front arms 19 and a reinforcing bracket 19e are made up of forming an aluminum alloy by means of integral casting, while the connecting pipe 19c is formed into a rectangular cylindrical section from extrusion molding material of the aluminum alloy. In addition, the rear arm 18 is formed by a taper angular pipe consisting of compression-molding a round pipe or a molding into a cross section angular form and such form becoming smaller in the cross section as far as the end side. |
