(1) Excavator relief valve
Structure The structure of the relief valve is shown in Figure 1-54.
The valve housing contains two types of relief valves to stop the normal and opposite rotation of the hydraulic motor. The overflow valve reduces the high pressure generated at the start or the turning action at the stop, and can control the overflow pressure from two steps of high pressure and low pressure, thus ensuring the free operation of the machine. :
(2) Relief valve function
① When the relief valve is lifted, the pressure acts on the valve. As shown in Figure 1-55 (a), the pressure at the oil port on the tank acts on the valve.
② As shown in Figure 1-55 (b), when the hydraulic oil pressure reaches the preset spring force, the condition on the valve when the plunger moves to the right.
③ As shown in Figure 1-55(c), the oil flow chamber g passes through the holes m and n. When the pressure of the oil flow chamber g reaches the preset force of the spring, the condition on the valve when the plunger moves to the left.
④ As shown in Figure 1-55 (d), when the plunger hits the bottom of the bushing, the state of the valve when the plunger stops moving to the left.
