- TAG :
The valve spring is an important part of the valve assembly in the valve train of an internal combustion engine. Its function is: when the valve is closed, the valve and the valve seat are kept closed and sealed by elastic force; during the valve opening and closing process, the valve and its driving mechanism are not separated from the control of the cam and move accordingly. The valve spring bears cyclical alternating load during operation, and must also overcome the additional load caused by the vibration that the mechanism may produce during high-speed operation. In addition, due to the limitation of the size of the cylinder head, the size of the valve spring is also limited, resulting in a serious stress state.
When the engine is running, the valve spring made of oil-quenched-tempered spring steel wire is not only used to ensure that the valve closes when it needs to be closed. More importantly, in the whole process of valve distribution, the valve can be guaranteed to move in accordance with the shape of the CAM profile. In order to prevent the tappet (or rocker arm) from leaving the cam profile instantaneously, that is, to ensure the sealing performance of the valve, the valve spring should have sufficient rigidity.The selected spring needs to have an appropriate stiffness, which is beneficial to reduce noise, vibration and wear caused by valve movement. In addition, in order to meet the long-term high-speed operation of the engine, the valve spring must have excellent fatigue resistance.