Engineering mining machinery parts Hydraulic valve cartridge balancing valve CBIG-LJN

Pilot relief valves are available in a variety of configurations. A typical three-section concentric structure pilot relief valve, which is composed of two parts: pilot valve and main valve.

The taper pilot valve, the damping hole (fixed throttle hole) on the main valve spool and the pressure regulating spring together constitute the pilot half-bridge partial pressure negative feedback control, which is responsible for providing the main stage command pressure after the pilot valve pressure regulation to the upper chamber of the main valve spool. The main spool is the comparator of the main control loop. The upper end face acts as the command force of the main spool, while the lower end face acts as the pressure measuring surface of the main loop and acts as the feedback force. The resultant force can drive the spool, adjust the size of the overflow port, and finally achieve the purpose of regulating and regulating the pressure of the inlet pressure P1.

YF type three-section concentric pilot relief valve structure Figure 1-(- taper valve (pilot valve); 2 - Cone seat 3 - valve cover; 4 - Valve body; 5 - damping hole; 6 - main valve core; 7 - Main seat; 8 - main valve spring; 9 - pressure regulation (pilot valve) spring; 10 - adjusting screws; 11 - Adjust the handwheel.

Work breakdown

When working, the liquid pressure acts on the pressure measuring surface of the main spool and the pilot spool simultaneously. When the pilot valve 1 is not opened, the oil does not flow in the valve chamber, and the pressure acting on the main spool in both directions is equal, but because the effective pressure area of the upper end is greater than the effective pressure area of the lower end, the main spool is in the bottom position under the action of the resultant force, and the valve port is closed. When the inlet pressure increases enough to open the pilot valve, the liquid flows through the damping hole on the main valve spool and the pilot valve back to the tank. Due to the damping effect of the damping hole, the main spool is subjected to the upper and lower directions of the liquid pressure is not equal, the main spool moves up under the action of the pressure difference, opens the valve port, realizes the overflow, and maintains the basic stability of the pressure. The overflow pressure can be adjusted by adjusting the pressure regulating spring of the pilot valve.