Common faults and maintenance of automobile pneumatic butterfly valve
Pneumatic butterfly valve is a vulnerable part in the process of automobile operation. The working quality of pneumatic butterfly valve will directly affect the stability of automobile driving and the life of other parts. Therefore, we should keep the pneumatic butterfly valve in good working condition. The following methods can be used to check whether the pneumatic butterfly valve works well.
1. Stop the car after driving 10km on the road with poor road conditions, touch the shell of the pneumatic butterfly valve with your hand. If it is not hot enough, explain that there is no resistance inside the pneumatic butterfly valve, and the pneumatic butterfly valve does not work. At this time, take part in the appropriate lubricating oil, and then stop the test. If the shell is hot, the pneumatic butterfly valve is short of oil, and it should be filled with oil; Otherwise, the pneumatic butterfly valve is invalid.
2. Press the bumper firmly, and then release it. If the car jumps 2-3 times, it indicates that the pneumatic butterfly valve works well.
3. If the vehicle vibrates violently in case of slow driving and emergency braking, it indicates that the pneumatic butterfly valve is faulty.
4. Dismantle the pneumatic butterfly valve to make it stand upright, clamp the lower connecting ring on the bench clamp, and pull and press the shock absorber rod several times. At this time, there should be stable resistance. The resistance of pulling upward should be greater than the resistance of pressing downward. If the resistance is unstable or no resistance, it may be the lack of oil inside the pneumatic butterfly valve or the damage of valve parts. Stop repairing or changing parts.
After confirming that the pneumatic butterfly valve has problems or failure, check whether the pneumatic butterfly valve can leak oil or has traces of obsolete oil leakage. The oil seal washer and seal washer are cracked and damaged, and the nuts of the oil storage cylinder cover are loose. The oil seal and sealing washer may be damaged and invalid, so the seal shall be replaced with a new one. If the oil leakage still cannot be eliminated, pull out the pneumatic butterfly valve. If you feel stuck or different, further check whether the clearance between the piston and the cylinder barrel is too large, whether the piston connecting rod of the pneumatic butterfly valve is bent, and whether the piston connecting rod surface and the cylinder barrel are scratched or pulled.
If there is no oil leakage in the pneumatic butterfly valve, check whether the pneumatic butterfly valve joint pin, joint rod, joint hole, bushing, etc. are damaged, desoldered, cracked or scattered. If the above inspection is normal, the pneumatic butterfly valve shall be further synthesized to check whether the fit clearance between the piston and the cylinder barrel is too large, whether the cylinder barrel is strained, whether the valve seal is good, whether the valve clack fits tightly with the valve seat, and whether the extension ball valve of the pneumatic butterfly valve is too soft or broken. The method of grinding or replacing parts shall be adopted according to the condition.
In addition, the pneumatic butterfly valve will produce noise in practical application, which is mainly caused by the collision between the pneumatic butterfly valve and the steel plate ball valve, the frame or the shaft, the damaged or scattered rubber gasket, the deformation of the dust cylinder of the pneumatic butterfly valve, the lack of oil and other reasons, the cause should be found out and repaired.
After the inspection and repair of the pneumatic butterfly valve is stopped, the working performance test shall be stopped on a special test bench. When the resistance frequency is 100 ± 1mm, the resistance of its stretching stroke and tightening stroke shall conform to the rules. For example, the maximum resistance of Jiefang CAl091 stretching stroke is 2156~2646N, and the maximum resistance of tightening stroke is 392~588N; The maximum resistance of Dongfeng truck in stretching travel is 2450~3038N, and that in tightening travel is 490~686N. If there is no experimental condition, we can also adopt an empirical approach, that is, use an iron bar to penetrate into the lower lifting ring of the pneumatic butterfly valve, step on both ends of the ring with both feet, hold the upper lifting ring with both hands and pull it back and forth for 2 to 4 times. When pulling upward, the resistance is great, and when pressing downward, it does not feel laborious. Moreover, the resistance of stretching is recovered compared with that before repair, and there is no sense of emptiness, It indicates that the pneumatic butterfly valve is basically normal.