Patent ID: 8225760

Claim:
A valve motion for an internal combustion engine which includes a camshaft which rotates in synchronism with rotation of said internal combustion engine, a driving cam which rotates integrally with said camshaft, a valve motion cam which makes relative rotation to said camshaft to open and close an engine valve, a link mechanism for transmitting valve driving force of said driving cam to said valve motion cam, a holder member which supports a fulcrum of said link mechanism thereon and is rockable around said camshaft, and a driving mechanism for rocking said holder member to vary the position of the fulcrum of said link mechanism and wherein a valve operation wherein in accordance with which said engine valve opens and closes can be changed by the rocked position of the fulcrum of said link mechanism, comprising: said driving mechanism includes a ball screw disposed over an intake side camshaft and an exhaust side camshaft and having threaded portions provided thereon which are threaded in different directions from each other on the intake side and the exhaust side, sliders individually provided on the intake side and exhaust side and movable on said ball screw, and connecting link members provided between said sliders and said holder member.