The camshaft is a part of the piston engine. Its function is to control the opening and closing of the valve. Although the speed of the camshaft in a four-stroke engine is half that of the crankshaft (in a two-stroke engine, the speed of the camshaft is the same as that of the crankshaft), the speed of the camshaft is usually still very high, and it needs to bear a lot of torque. Therefore, the design of the camshaft requires a high degree of strength and support, and its material is generally excellent. Carbide steel or alloy steel. Because the valve motion law is related to the power and running characteristics of an engine, camshaft design plays an important role in the design process of the engine.