| 摘要 |
PURPOSE:To facilitate forming work, to increase the sticking strength and to improve the reliability by firmly fixing a web and a gear body by plastic deformation of a metal in a power transmission spur gear of a motorcycle or the like. CONSTITUTION:A driven gear fitted to a rear axle S comprises a circular web 34 made of steel plate and an annular gear body 35, wherein a pair of peripheral grooves 37, 38 are formed on the inner peripheral surface 35a of the gear body 35 at the substantially central position in the axial direction thereof and on the outer peripheral surface of the end portion of the rear axle S, respectively, and further a knurled groove 39 is formed between the peripheral grooves 38, 38 of the rear axle S. The web 34 is fitted in the gear body 35, the rear axle S is fitted in a fitting hole 36 of the web 34, and the side of the outer peripheral portion of the web 34 and an opening edge of the fitting hole 36 are simultaneously pressurized by a metal mold M to form annular recess portions 40, 41 by plastic deformation. The respective elastic deformed portions 42, 43 are pressed in the peripheral grooves 37, 38 and the knurled groove 39 to be fixed therein. Thus the sticking strength can be increased to improve the reliability of sticking.
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