Patent ID: 8899200
Filing Date: 2014-12-02
Classification: F01L,F16F

Abstract:
1. A valve spring retainer made of steel in an internal combustion engine, the valve spring retainer comprising: a frusto-conical part having a taper hole; and a spring-retaining flange pressed by an upper end of a valve spring, wherein carburizing, quenching and tempering are applied to the valve spring retainer to form oxide film, the oxide film being partially removed at part of the spring-retaining flange pressed by the upper end of the valve spring to allow thickness of the oxide film to be 0.00-0.02 μm, exclusive to zero; wherein a lower surface of the spring-retaining flange pressed by the upper end of the valve spring is tilted at an angle of less than 1.0 degree to rise away from a center of the valve spring retainer.