1) Doosan excavator overload charge valve structure
2) The role of overload charge valve
Overcharge oil filling
The overload charge valve is installed on each branch of the 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 abnormal impact force from the outside, abnormal high pressure will be generated in the cylinder, and the safety oil suction valve will be opened to discharge the abnormal high pressure back to the oil tank. In this case, the reading should play a safety role to protect the related hydraulic cylinders and hydraulic tubing
2. When negative pressure is generated in the cylinder, the valve acts as an oil suction valve to supplement the oil from the tank line to the negative pressure area to avoid the formation of a vacuum and cavitation
Note: When one side is used as a safety valve, the other side acts as an oil-absorbing device.
2) Working principle of overload charge valve
Safety effect:
①The oil pressure in the high-pressure oil area rose to 21.6P
②High-pressure oil pushes the poppet valve (5) to open upwards against the force of the spring (6) ⑧ The 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 effect of the throttle groove
⑤ The main valve (2) opens upwards against the force of the spring (4) due to the pressure difference
⑥ A large amount of high-pressure oil can be drained back to the tank, and the main oil pressure drops
⑦Protected 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 oil tank acts on the circular force-bearing surface of ΦA-ΦD, pushing the suction valve (1) to open upward
③ Fuel tank oil is filled into this negative pressure area to avoid the formation of bubbles and cavitation.
