| 摘要 |
1,191,202. Making cam-shafts; casting processes. NIPPON PISTON RING CO. Ltd. 25 March, 1968 [1 April, 1967], No. 14306/68. Headings B3A and B3F. [Also in Divisions C7 and F2] A cam-shaft 1 has an axial oilway and bores 4 leading from the oilway to the cam surface to effect surface lubrication. A core assembly 5 comprising a solid steel rod 6 completely coated with a substance of low heat conductivity 7, e.g. resin, and closely fitted within a polished mild steel tube 3 is placed in a shell or sand mould. An alloy steel is poured at 1310‹ to 1350‹ C. into the mould. Preferably the mild steel tube 3 is coated with copper to ensure its adhesion to the cast alloy. The steel rod 6 is removed from the casting, the heat-decomposed layer 7 facilitating this removal. The mild steel tube then forms the oilway and acts as a reinforcing insert. The bores 4 are drilled from the surface to the oilway. |
