1) Structure of Doosan Excavator Overload Supplement Valve
2) The role of the overload replenishment valve
Overload replenishment
Overload supplement valve is installed on each branch oil circuit of hydraulic device (cylinder, motor). It has the following two functions (take the oil cylinder as an example):
1. When the working device is subjected to an abnormal impact from the outside, abnormal high pressure will be generated in the oil cylinder, and the safety suction valve will be opened to discharge the abnormal high pressure back to the fuel tank. In this case, it should be used as a safety guard to protect the relevant hydraulic cylinders and hydraulic tubing.
2. When negative pressure is generated in the oil cylinder, the valve acts as an oil suction valve to replenish oil from the tank pipeline back to the negative pressure zone to avoid the formation of vacuum and cavitation
Note: When one side is used as a safety valve, the other side is used to absorb oil.
2) The working principle of the overload charge valve
Safety function:
①The oil pressure in the high-pressure oil zone rises to 21.6P
②The high-pressure oil pushes the poppet valve (5) to overcome the force of the spring (6) to open upwards. ⑧The oil in the throttle groove of the piston (3) starts to flow a little
④The pressure difference between the upper and lower piston (3) due to the throttling action of the throttle groove
⑤The main valve (2) opens upwards against the force of the spring (4) due to this pressure difference
⑥A large amount of high-pressure oil can be drained back to the fuel tank, and the pressure of the main oil circuit drops
⑦ protects the cylinder and tubing
working principle
oil absorption:
①When the E zone is negative pressure, the oil pressure is lower than the tank pressure
②The oil pressure of the fuel tank acts on the circular force surface of ΦA-ΦD, pushing the suction valve (1) upward to open
③The fuel tank oil is added to this negative pressure zone to avoid the formation of air bubbles and cavitation.
