Common faults and maintenance methods of automobile pneumatic butterfly valve Check whether there is oil leakage first
In order to rapidly attenuate the vibration of the frame and body, and improve the smoothness and warmth of the vehicle, the vehicle suspension system is generally equipped with shock absorbers. At present, the two-way acting cylinder shock absorbers are widely used in vehicles.
The shock absorber is a vulnerable part in the process of vehicle operation. The working quality of the shock absorber will directly affect the stability of the vehicle and the life of other parts. Therefore, we should keep the shock absorber in good working condition. The following methods can be used to check whether the shock absorber works well.
1. Stop the car after driving 10km on the road with poor road conditions, touch the shock absorber shell with your hand. If it is not hot enough, it is clarified that there is no resistance inside the shock absorber and the shock absorber does not work. At this time, take part in the appropriate lubricating oil, and then stop the test. If the shell is hot, it means that the shock absorber is short of oil, and it should be filled with enough oil; Otherwise, it indicates that the shock absorber is invalid.
2. Press the bumper firmly and then release it. If the car jumps 2-3 times, it indicates that the shock absorber works well.
3. If the vehicle vibrates violently when the vehicle drives slowly and brakes urgently, it indicates that there is a problem with the shock absorber.
4. Dismantle the shock absorber and erect it, clamp the lower connecting ring on the bench clamp, and pull and press the shock absorber rod several times with force. At this time, there should be stable resistance. The resistance to pull up (recover) should be greater than the resistance to press down. If the resistance is unstable or no resistance, it may be due to lack of oil in the shock absorber or damage of valve parts, and repair or replacement of parts should be stopped.
5. After confirming that there is a problem or failure of the shock absorber, check whether the shock absorber can leak oil or has traces of obsolete oil leakage.
6. The oil seal washer and seal washer are cracked and damaged, and the nuts of the oil storage cylinder cover are loose.
If oil leakage is found, first tighten the nuts of the oil cylinder head. If the shock absorber still leaks oil, it may be that the oil seal and sealing washer are damaged and invalid. Replace them with new seals. If the oil leakage still cannot be eliminated, pull out the shock absorber rod. If you feel that the piston is jammed or the weight is different, further check whether the clearance between the piston and the cylinder barrel is too large, whether the piston connecting rod of the shock absorber is bent, and whether the piston connecting rod surface and the cylinder barrel are scratched or pulled.
If the shock absorber has no oil leakage, check whether the shock absorber connecting pin, connecting rod, connecting hole, bushing, etc. are damaged, desoldered, cracked or scattered. If the above inspection is normal, the shock absorber 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 and the valve seat fit tightly, and whether the stretching ball valve of the shock absorber is too soft or broken. According to the condition, the method of grinding or replacing parts shall be adopted for repair.
In addition, the shock absorber will produce noise in practical application, which is mainly caused by collision between the shock absorber and the steel plate ball valve, frame or shaft, damaged or scattered rubber pad, deformation of the dust cylinder of the shock absorber, lack of oil and other reasons. The reason should be found out and repaired.
After stopping inspection and repair, the shock absorber shall stop working performance test 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 Trucks during stretching is 2450-3038N, and the maximum resistance during tightening 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 shock absorber, step on its two ends with both feet, hold the upper lifting ring with both hands and pull it back and forth for 2-4 times. When it is pulled upward, the resistance is great, and when it is pressed downward, it does not feel laborious. Moreover, the resistance of stretching is recovered compared with that before repair, and there is no idle feeling, indicating that the shock absorber is basically normal.