| 摘要 |
PURPOSE:To prevent the growth of abrasion by way of providing light-weight construction and improving the lubricating-oil holding capacity by using an aluminum alloy having a structure in which fine crystallized silicon is dispersed as the material of a camshaft, and then forming a hard alumite layer on its surface. CONSTITUTION:The basis material 1 of a camshaft is to be an aluminum alloy casting, which consists of a high-silicon aluminum alloy containing approximately 15-26% of silicon. In the case of such casting, the primary crystal silicon is used to be crystallized in its structure, and such primary crystal silicon is caused to be dispersedly crystallized as finely and uniformly as possible. On the surface of said basis material is provided a hard alumite layer by way of conventional processing methods. Hereupon, in the neighborhood of the silicon is not formed said hard alumite layer but formed a recessed part, which acts as a lubricating-oil holding layer. |
