The materials excavated by the excavator are mainly soil, coal, sand and soil and rock after pre loosening. According to the development of construction machinery in recent years, the excavator has developed relatively fast, and the excavator has become one of the most important construction machinery in engineering construction. The three most important parameters of the excavator: operating weight (mass), engine power and bucket capacity.
If the working device (oil cylinder) of the excavator falls naturally, check and determine whether the sealing ring of the oil cylinder is damaged or the main valve has internal leakage according to the following methods.
1. Check the cylinder tightness
Seal: check boom and bucket cylinders
① Adjust to the same state as when measuring the natural descent amount, and the engine shuts down.
② . operate the boom control lever to the lifting position and the bucket control lever to the bucket lifting position.
A. If the lowering speed increases, the oil cylinder is poorly sealed.
B. If there is no change, the boom hold valve (boom) or the main valve (control bucket) is faulty.
Check the stick cylinder:
① Fully retract the stick cylinder and stop the engine.
② Operate the control lever to the stick dig position.
A. If the lowering speed increases, the oil cylinder is poorly sealed.
B. If there is no change, the main valve is damaged (if there is no pressure in the accumulator, run the engine for about 95 > and then charge the accumulator).
2. Inspection of boom holding valve
(1) Adjust the working device to the maximum radius and the boom top is horizontal, and then stop the engine; Lock the safety lock lever to release the pressure in the hydraulic tank.
(2) Remove the pilot hose of the boom holding valve. If the open oil port leaks oil, it can be judged that the boom holding valve is faulty.
3. Check PPC valve
When the engine is running and the safety lock lever is in the locked position or released, the natural lowering amount is different, then the PPC valve is faulty.
