By what is the valve spring seat secured?

When the valve assembly is opened, the valve assembly should not be separated from the cam control under the inertial force generated by negative acceleration, and the valve should maintain a good seal when closed. While meeting the above requirements, the spring should also meet its own reliability requirements and should not break.

Valve spring materials mainly include 50 types of CrVA, 60SiCrA, 60Si2CrVA, and 65Mn. Alloy steel wires have high fatigue strength, but are sensitive to surface quality. Therefore, the surface of the spring steel wire needs polishing, with a surface roughness of 0.32 μ When selecting materials, it is necessary to fully grasp the fatigue characteristic data of the materials.

The optimization design of the valve spring seat adopts the optimization theory "full stress design principle" that is easily accepted by engineering designers, that is, to design the shear stress of the spring according to the allowable value. It is well known that if the large shear stress of a spring is higher than the allowable force, it is unsafe, and if it is lower than the allowable value, it is conservative. Therefore, designing a spring according to the allowable stress value can make good use of the spring material, and the volume or weight of the spring is obviously small.

In the new design, the fatigue safety factor of the spring can be designed according to the specified allowable value. When improving the design, for double springs, a group close to the fatigue safety factor of the inner and outer springs can be selected; When the valve is fully open, the gap between the spring ring and the ring can be designed based on a specified value.

The valve spring seat is fixed by a conical valve lock block. The following are the functions of the valve spring seat:

The function of the valve spring is to ensure the accurate reset of the valve, that is, to overcome the gap caused by the inertial force of the valve and transmission components during the valve closing process, ensure that the valve immediately sits down and closely cooperates, and at the same time, avoid damage to the seal due to pulsation of the valve during engine vibration;

When installing the valve spring, one end is supported on the cylinder head, and the other end is pressed against the spring seat at the end of the valve stem, which is fixed to the end of the valve stem with a lock ring or pin;

In order to ensure sufficient spring stiffness and installation preload, valve springs are mostly made of high carbon manganese steel or chromium vanadium steel wire. Silicon chromium steel wire. Most valve springs are made of cylindrical equal pitch springs. When installing valve springs in the engine, use different pitch springs to avoid resonance.