Pressure control valves are available in both hydraulic and pneumatic pressures, but the principle is almost the same. Here is the hydraulic valve structure:
1-Adjustment screw; 2-valve body; 3-regulator spring; 4-bias disk; 5-cone valve; 6-damper piston
The role of the damping piston is that when the cone valve is opened or closed, it plays a role in damping, which is used to improve the pressure regulation stability of the valve. Second, it acts as a guide for the cone valve to improve the sealing performance of the valve.
The role of bias plate: bias plate has an annular groove on it to change the flow direction of the oil outlet of the cone valve. Then, the deflector plate is subjected to a hydraulic force. This hydraulic force acts in the opposite direction of the spring force and flows with the overflow. Increase and increase. As the overflow increases, the spring force increases due to the increased opening of the poppet. However, because the hydrodynamic forces also increase at the same time, the structure counteracts the increment of the spring force. Therefore, the inlet pressure of this kind of valve is not affected by the change of flow rate. The Q characteristic curve of the household is ideal, and the opening and closing characteristics are good, which is beneficial to increase the rated flow of the valve.
(1) Acting as a safety valve (to prevent overload of the hydraulic system) When the relief valve acts as a safety valve, it is intended to limit the maximum pressure of the hydraulic system to ensure the safety of the system. Under normal operating conditions of the system, the valve is closed without overflow, and the working pressure of the system is determined by the external load. When the system pressure reaches the set pressure of the valve, the valve opens to overflow. At this time, the system pressure is determined by the set pressure of the relief valve.
(2) Relief valve function (Maintain hydraulic system pressure constant) In the throttle system, the relief valve is normally open during normal operation, and the excess hydraulic fluid is drained back to the tank to maintain the hydraulic system pressure. Constant.
(3) To make the hydraulic system unload the remote control port of the pilot relief valve, the relief valve can be used to unload the system. The DBW pilot electromagnetic relief valve can realize the system using its own solenoid reversing valve. Unloading, and other pilot relief valve to achieve system unloading, it is necessary to add a directional valve on the remote control port.
(4) Remote pressure regulation The remote pressure control valve on the remote control port of the pilot relief valve can realize remote pressure regulation.
In addition, the relief valve can also be used as a back pressure valve to make the system work smoothly; the relief valve and the reversing valve can be used to realize the multi-stage pressure control of the system; in the brake circuit, the relief valve can be used to realize the system. Acting; In the hydraulic test bench system, the overflow valve can be used as a load valve.