Suitable for PC400-6 gun 723-90-61400 relief valve

Where is the relief valve of the excavator

Above the dispensing valve, same shape. You first look at the hydraulic pump above, you will see that there are two pipes of the same size, will be thicker than other pipes, these two pipes are to the distribution valve, the distribution valve above the corresponding control valve with these two pipes is the relief valve. The relief valve has a constant pressure overflow effect: in the quantitative pump throttling regulation system, the quantitative pump provides a constant flow rate. When the system pressure increases, the flow demand will decrease. At this time, the relief valve is opened, so that the excess flow flows back to the tank, to ensure that the relief valve inlet pressure, that is, the pump outlet pressure is constant (the valve port is often opened with pressure fluctuations).

The role of the relief valve

Spillover effect. The throttle valve can adjust and balance the flow in the hydraulic equipment when the quantitative pump is supplying oil. The role of security protection. Prevent accidents caused by excessive load of hydraulic equipment and machine tools. Used as a discharge valve. The pilot safety valve and two two-way solenoid valve are used together and can be used as a unloading system. Remote control and pressure regulation valves. High and low multistage control. Used as a sequence valve.

If the relief valve of the excavator is broken, it will affect the action, and the oil pressure cannot be transmitted to the upper chamber of the main valve and the front chamber of the pilot valve, and the pilot valve will lose its regulating effect on the pressure of the main valve; Because there is no oil pressure in the upper chamber of the main valve and the spring force is very small, the main valve becomes a direct-acting relief valve with a small spring force. When the pressure of the oil inlet chamber is very low, the main valve will open the overflow, and the system will not be able to establish pressure.