Valve Gear

Abstract

The reliability of a valve gear in which a cobalt-based alloy is welded by plasma powder building-up welding is improved. Disclosed is a valve gear including a bearing 2 having a sliding surface against a valve shaft 1, the valve gear being characterized in that: a welded layer 12 made of a heat-resistant cobalt-based alloy, based on plasma powder building-up, is formed on the sliding surface against the valve shaft 1; and the welded layer 12 includes a first welded layer 12a formed on the surface of the bearing 2, having a dilution ratio of 5 to 25% and a second welded layer 12b formed on the first welded layer 12a, having a dilution ratio of 50% or less of the dilution ratio of the first welded layer 12a. The dilution ratio is a parameter indicating the penetration amount of the welding metal into the base metal, and means a value obtained by B/A×100 (%) wherein A represents the total amount of the welded metal and B represents the amount of the welding metal penetrating into the base metal.

Dependencies are inferred from the claim text.