There is no oil flow through the orifice and therefore equal to the pressure at both ends of the main spool, the main spool is in the lowermost position in the relatively soft spring under the action of the main valve, the relief valve port P and T cut-off and no overflow.
Rexroth DB10 5X Rotary Knob Pilot Operated Pressure Adjustment Pressure Relief Valve
Rexroth DB10 5X Rotary Knob Pilot Operated Pressure Adjustment Pressure Relief Valve
When the inlet pressure rises to the fluid pressure acting on the pilot valve is larger than the spring force of the pilot valve, the pilot valve opens, the pressure oil can be through the orifice , back into the tank via the pilot valve , since the effect of the orifice, so that the hydraulic pressure of the upper end of the main spool is smaller than the lower end of the pressure.
When the force of this pressure differential acting on the main spool area is equal to or exceeds the spring force of the main valve, the axial direction of the steady - state fluid power, friction, and own weight, the main spool open, oil flows from P port, the main valve port back into the tank from T port to achieve overflow.
Rexroth DB10 5X Rotary Knob Pilot Operated Pressure Adjustment Pressure Relief Valve Figuration Drawing:
