Maintenance of main parts of shock absorber
  • Automotive

In order to rapidly reduce the vibration of the frame and the car body and improve the ride comfort and comfort of the vehicle, shock absorbers are usually installed on the suspension system. At present, bidirectional vibration absorber is widely used in automobiles. Shock absorber is a vulnerable part in the process of vehicle operation. The work of the shock absorber will directly affect the smoothness of the vehicle and the life of other parts. The hydraulic two-way shock absorber is usually installed on the outside of the front suspension of the vehicle, and is connected with the bracket on the frame and the vehicle bridge respectively through the rubber bushing and the connecting pin. The damper has 3 concentric steel tubes, the outer steel tube is a dustproof cover, the middle is the oil storage cylinder, and the inside is the working cylinder; the upper end of the piston rod is integrated with the dustproof cover and the upper ring, the piston is fixed at the lower end, the extension valve and the circulation valve are installed on the piston, and the pressure and shrinkage valve and compensation valve are installed on the bottom support of the working cylinder. When the shock absorber works, the oil storage cylinder and the working cylinder move along with the axle, and the dust cover, piston rod and piston move along the frame. The working cylinder is filled with oil, and a certain amount of oil is stored in the oil storage cylinder. The upper part of the working cylinder is equipped with a guide seal. Circulation valve and compensation valve is a one-way valve, its spring is more soft, the smaller oil pressure can be opened or closed, the extension valve and compression valve are unloading valves, high oil pressure open and close. The working process of shock absorber is divided into two strokes: compression and extension. When the vehicle bridge moves closer to the frame, the damper is compressed. In the compression stroke, the piston moves down, reducing the volume of the lower cavity, increasing the oil pressure, increasing the volume of the upper chamber, reducing the oil pressure, and opening the valve to the upper chamber of the piston. As the piston rod occupies part of the upper chamber volume, the volume of the upper chamber is less than the volume of the lower chamber, and the excess oil can only be pressed into the cylinder of the oil storage cylinder. The throttling resistance generated by the flow of oil through the valve holes can damp the vibration of the frame and cause vibration attenuation. At this point, the special structure of the circulating valve and the compression valve makes the oil pressure and damping force not too large, and the leaf spring can give full play to the buffering and damping effect. When the shock absorber is removed, clean the surface dirt of the shock absorber shell first, and clamp the lower connecting ring on the vise. Pull the hoisting ring, pull the shock absorber as far as possible, clamp the storage tank assembly vertically on the vise, and use the special spanner to unscrew the top cover. Pull the dustproof hood upwards, and the connecting rod assembly, connecting rod, guide seat and piston assembly can be pulled out from the cylinder. The assembly sequence of the shock absorber is as follows: invert the dust cover with the connecting rod and clamp the hanging ring with the vise. Loading cylinder nuts, connecting rod oil seal cover, sealing ring, connecting rod oil seal, oil seal washer, oil seal spring and guide seat successively. The limit seat is installed at the step of the front end of the connecting rod, and then loaded into the circulation valve spring piece, the valve piece, the piston, the reset valve piece, the supporting ring, the reset valve spring and the pressing nut. Press the compression valve assembly into the working cylinder by hand pressing to make it close to contact. The lower ring of the oil storage tank is clamped on the vise, and the working cylinder assembly is loaded into the oil storage cylinder to make the compression valve end downwards. A proper amount of oil is injected in accordance with the relevant requirements. Put the connecting rod with the piston into the working cylinder, so that the stopper of the guide seat can be inserted into the working cylinder. The rubber sealing ring is positioned on the guide seat, and the nut of the oil storage cylinder is tightened by a special spanner. 1. ring. When the welding rings need to be welded, the groove must be made, and the rings should be in the center of the cylinder without being skewed. Otherwise, it will produce "no strength" after installation, resulting in excessive wear or damage. 2. oil storage cylinder is the main component of shock absorber, inspection must be carried out according to the following aspects: the thread part must not produce clasp and slipping, otherwise the oil cylinder nut can not be tightened, thus causing the working cylinder to jump up and down, not only making noise but also causing change shape, which directly affects the adhesion performance of the vehicle and the performance of the vehicle. Driving safety. 3. the oil leakage of the shock absorber at the connecting rod is mostly caused by the damage of the oil seal. The overworn oil seal and the aging oil seal should be replaced. The outer diameter of the 4. piston has a very important effect on the stability of the shock absorber. Once the valve line on the outer surface of the piston is sealed, it will directly affect the damping performance of the shock absorber once it is broken by the valve plate, and it will be restored after repair. The method of repair is to use the auxiliary tool to grind with manual or high precision machine tools, to reach the corresponding precision by the envoy flow hole, and to ensure that the plane of the valve line is 0.03 to 0.05 mm higher than the supporting surface, which can obviously improve the resistance of the damper. If the valve line is damaged many times, the piston will not be repaired and new parts should be replaced. 5. the 4 claws of the compression valve spring piece are deformed or broken, so that the damping resistance of the shock absorber is reduced or lost. Because the compression valve assembly is made of punching and riveting into a non detachable whole, the assembly can only be replaced if necessary. 6. after long term use, the absorber oil will become black and thick. If the piston is cast iron or powder metallurgy piston, the oil will contain powdered iron filings, which can be rolled out by hand. When the shock absorber oil becomes black, the oil must be replaced. When 7. welding cylinder base and oil tank are welded, the oxidation skin and slag produced by high temperature rolling welding are easily retained at the bottom of the cylinder. It will fall off under the scour of high temperature and high pressure liquid flow, plug the throttle hole or clamp the cylinder and piston, pull the cylinder and piston. Therefore, it is best to use high pressure or ultrasonic to clean the oil storage tank and clean it with compressed air after cleaning. 8. usually three bump points are punched out on the base of the oil storage cylinder to locate the compression seat of the working cylinder. As the stamping deformation is large, it is very easy to cause cracks in the root of the protruding root, resulting in oil leakage. 9. the three convex points of the oil storage tank should be located in the same conical surface, and the working cylinder should be centered when placed. If the three is not in the same cone when the connecting rod is reciprocating, the working cylinder will wobble. It will not only produce noise, but also cause the connecting rod and cylinder hairpin to produce early wear. In order to identify the above fault, the position of the convex starting point can be observed after the shock absorber is decomposed and cleaned. If there is a clear bright spot, it is indicated that the convex starting point is not on the same cone with the other two convex starting point. The working cylinder can also be placed in the storage tank to observe whether it is centered or not, which means that the three convex points are not on the same cone surface.