The camshaft is a component in a piston engine. Its role is to control the opening and closing actions of the valve. Although the rotational speed of the camshaft is four times that of the crankshaft in a four-stroke engine (the rotational speed of the camshaft is the same as that of the crankshaft in a two-stroke engine), but usually its rotational speed is still high and it needs to withstand a lot of torque The requirements of the camshaft in terms of strength and support are very high. The material of the camshaft is generally special cast iron, and occasionally forgings are also used. Since the valve motion law is related to the power and operating characteristics of an engine, the camshaft design occupies a very important position in the engine design process.