The hydraulic system of the full hydraulic excavator consists of 4 parts: power element, actuating element, control element and auxiliary element.
Most of the power components are variable plunger pumps, which function to convert the mechanical energy of the engine into the pressure energy of the liquid. The common fault phenomenon is that the pressure of the pump oil is insufficient and the flow rate is reduced. If this phenomenon is gradual and the temperature is higher and more obvious, it is caused by the excessive wear of the hydraulic pump; if this phenomenon is sudden, it is caused by no work of a plunger; if the pressure is normal, the flow rate decreases suddenly, which is usually caused by the small flow position of the variable mechanism card.
Actuators include hydraulic cylinders and hydraulic motors, whose function is to convert the pressure of liquid into mechanical energy, the common failure phenomenon is slow or no action. If both the pump and the valve have no fault, the reason for the slow motion of the actuator is due to its excessive wear and tear; if the pump works normally and the action of a certain actuator is slow, it is likely that the valve has a failure to control the actuator, such as the valve is not in place, the overflow valve is closed or the spring force is weakened, and so on. There will be no difference between the wear and tear of the actuating elements. If other reasons are caused, the action of multiple actuating elements should be slowed down at the same time; if the known pump and valve are all without fault, the sudden no action of a certain actuator is caused by the death of its internal card.
The control elements include various valves, such as pilot valves, multiway valves, main safety valves, relief valves and one-way throttle valves. Although the functions of various valves vary greatly, their common faults vary greatly, mainly hair clip, loosely closed and spring elasticity weakening and leakage and so on.
Auxiliary components mainly include oil tank, tubing, radiator, filter and accumulator. The function of the radiator is to distribute the heat generated by the hydraulic system to the atmosphere. Its common faults are oil leakage and poor heat dissipation. The function of the filter is to filter impurities mixed into hydraulic oil, and its common faults are filter clogging and so on. The function of the accumulator is to stabilize the oil pressure and store a certain amount of energy, so as to ensure that the operation is stable and when the engine fails to work, the working device can be reduced to the ground. The common fault has the poor energy storage effect, and the above functions can not be completed. The fault phenomena of auxiliary components are generally obvious and easy to diagnose.
