Valve mechanism of internal combustion engine

摘要

A drive shaft is synchronously rotated with a crankshaft of an internal combustion engine. A cylindrical hollow cam shaft is rotatably disposed about the drive shaft keeping a first cylindrical clearance therebetween. The cam shaft is formed with at least one cam that actuates an engine valve for opening and closing the same. A bearing bears a given portion of the cam shaft keeping a second cylindrical clearance therebetween. A movement transmitting mechanism transmits a torque of the drive shaft to the cam shaft while converting a rotation movement of the drive shaft to a swing movement of the cam shaft. The thickness of the first cylindrical clearance is smaller than that of the second cylindrical clearance.