Patent ID: 7228836
Filing Date: 2007-06-12
Classification: C22F,F01L,Y10T

Abstract:
1. A spring retainer for retaining one end of a valve spring for biasing intake/exhaust valves to a closed position, comprising a cylinder, a brim formed integrally with the cylinder and extending radially outward from an upper end of the cylinder, wherein the spring retainer comprises a titanium alloy formed by cold forging at least in the finishing process, and a slope formed on a top of the brim by compressing the brim obliquely downwardly during the cold forging such that the brim has a thickness decreasing in a radially outward direction, wherein the titanium alloy comprises an α-type titanium alloy containing 0.5 to 1.5 mass percent of iron and 0.2 to 0.5 mass percent of oxygen in addition to titanium and other inevitable impurities.