What are the assembly technical requirements for the valve key clip?

The valve clamp greatly improves the intake and exhaust efficiency of the engine, improves the combustion efficiency of the engine at high speeds, and can output more rated power, reducing exhaust emissions. In the process of engine manufacturing, the assembly standards for cylinder head valve assemblies have also been improved, and traditional visual and slap testing can no longer meet existing process standards. The application of laser detection technology can effectively monitor the assembly status of valve clamps and components, providing reliable assurance for the consistency of product performance.

Technical requirements for assembly of valve lock clips

1. Product Design Standards

In theory, after valve assembly, the height between the valve top and the spring seat and the height between the spring seat and the lock clip are the control dimensions during the manufacturing process. The values of A and B should be judged as qualified assembly within a certain range.

Generally speaking, the height a from the top of the valve to the spring seat depends on the design criteria and is used to determine the assembly position of the valve spring seat. However, the height a from the valve clamp to the spring seat requires strict requirements. In order to meet engineering requirements, the height difference from the lock clip to the spring seat should meet the size range of -0.8mm to 0.8mm.

2. Production line assembly standards

After pressing the valve clamp and spring seat with equipment or tools, the convex point of the clamp is completely stuck in the valve slot and in a clamped state; By tapping the valve, the lock clip does not fall off, bulge, or sag.

3. Quality risk of valve key clip assembly failure

If the valve clamp assembly fails, a series of quality problems such as the clamp falling off and the valve train failure may occur, resulting in the valve not being able to open and close normally, the valve clamping failure, and the valve hitting the cylinder. All of the above phenomena can cause the engine to fail to operate.

Valve inspection process method

There are three main methods for valve testing: manual visual inspection, valve tapping, and automatic equipment testing.

Compared with automatic equipment detection, the reliability and stability of artificial visual inspection are significantly insufficient. Artificial visual inspection can only judge the assembly status of the valve through the senses. If there are obvious locking clips that are not pressed in place, missing or incorrectly installed, it cannot be guaranteed that manufacturing defects are 100% controlled during the manufacturing process.

The valve tapping is performed after the completion of the valve lock clamping device. In this process, the valve moves up and down by simulating the movement of the mechanism. If the lock clamping device is not qualified, the lock clamp can easily jump out or fall into the cylinder head during the tapping process. The disadvantage of this method is that the tapping device cannot automatically determine whether the assembly of the valve lock clip is qualified, and manual inspection needs to be added at subsequent stations. However, compared to simple artificial visual inspection, the method of valve tapping improves the reliability of lock clip quality control to a certain extent.

The automatic equipment inspection method can make up for the shortcomings of manual inspection and valve tapping, and better achieve online control of valve assembly quality. Generally, laser scanning inspection is used to judge the assembly quality of the valve. The laser scans the intake/exhaust side valves, valve clamps, spring seats, and other related components of the cylinder head along the set path, performs a series of dimensional calculations, and then compares them with the range set in the program to determine the rationality of the assembly between various components.