The hydraulic system of the excavator is a combination that organically connects various hydraulic components with pipelines according to the transmission requirements of the working device and various mechanisms of the excavator. It mainly includes hydraulic oil tank, main pump, multi way valve, various pipelines, oil cylinders and motors that perform various actions. Its function is to take oil as the working medium, use the hydraulic pump to convert the mechanical energy of the engine into hydraulic energy and transmit it, and then convert the hydraulic energy back to mechanical energy through the hydraulic cylinder and hydraulic motor, so as to realize various actions of the excavator. Overflow valve is an important part of pressure control in hydraulic system of excavator. This article will summarize the function of overflow valve in excavator.
1. Safety protection function
When the hydraulic system works normally, the valve is closed. Only when the load exceeds the specified limit, that is, when the system pressure exceeds the set pressure, the overflow will be started for overload protection, so that the system pressure will not increase. Generally, the set pressure of the overflow valve is 10%~20% higher than the maximum working pressure of the system.
2. Stabilizing action
The overflow valve is connected in series on the oil return circuit to generate back pressure, which increases the stability of moving parts.
3. Constant pressure overflow
In the throttling regulation system of constant displacement pump, the constant displacement pump provides constant flow. When the system pressure increases, the flow demand decreases. At this time, the overflow valve is opened to overflow the excess flow back to the oil tank. Ensure that the inlet pressure of the overflow valve, that is, the pump outlet pressure, is constant. The valve port is often opened with pressure fluctuation.
4. Unloading effect of system
The remote control port of the overflow valve is connected in series with the solenoid valve with small overflow flow. When the electromagnetic iron is energized, the remote control port of the overflow valve is connected to the oil tank. At this time, the hydraulic pump is unloaded. The overflow valve is now used as the unloading valve.
