| 摘要 |
PURPOSE:To reduce mounting area while equalizing stress by providing flatted portions on the outermost sides of coil in the longitudinal section of a coil spring used for a valve spring or the like in a valve driving mechanism of an engine to provide a deformed section. CONSTITUTION:The longitudinal sectional shape of a coil spring is formed on the outer periphery BAD of the inside half with an oval shape while being provided on the outer periphery E1, C1, F1 of the outermost side with a flattened portion P1 along the direction of the center axis of the coil spring. Thus, in compression or extension of the spring, stress share in the surface portion near the outermost side outer periphery E1, C1, F1 in the longitudinal section is increased so that approximately uniform stress is produced on the surface portions of the outer periphery ABE1C1F1DA of the longitudinal section. |
