Patent ID: 7647912

Claim:
A structure including a camshaft supported in a supporting member, wherein said camshaft comprises: a shaft body of circular cross section; a plurality of substantially oval-shaped cam lobes provided on a circumference of said shaft body; and a large-diameter part provided on the circumference of said shaft body, said large-diameter part being disposed between a plurality of said cam lobes and being concentric with said shaft body, wherein said large-diameter part has an external diameter which is the same size as or larger than that of a cam base in said cam lobe, wherein said supporting member comprises: a pair of bearing holes for rotatably supporting both ends of said shaft body provided therein; a first bearing hole of said pair of bearing holes having a circular shape of a size which allows said cam lobe to penetrate there through and having an internal diameter which is larger than an internal diameter of a second bearing hole of said pair of bearing holes such that said internal diameter of said second bearing hole will not allow said cam lobe to penetrate therethrough; and a concave bearing portion having an arc shape, said concave bearing portion being provided in said supporting member so as to support a pressing load supplied from the side of a valve onto said cam lobe, and wherein said large-diameter part of said cam is rotatably disposed in said concave bearing portion of said supporting member.