SHOE A 0534488 - Caterpillar

Pressure and flow compensator valve (6) is mounted to the pump. Pressure and flow compensator valve (6) contains two spools. Margin spool (16) regulates the pump output flow in response to load sensing signal port (15).Pressure and flow compensator valve (6) maintains the correct pressure and correct oil flow. The flow and pressure of the pump are maintained by sending pump oil to control piston (3) or draining pump oil from control piston (3).Control piston (3) and bias spring (1) work together in order to adjust the angle of swashplate (11). Pressure and flow compensator valve (6) prevents overloading of the pump. Pump Destroke
Illustration 3 g01513195
Piston pump in destroke
(2) Swashplate
(7) Bias spring
(9) Actuator piston
(11) Pump outlet port
(14) Margin spring
(15) Load sensing port
(16) Margin spool
(17) Spool control orifice
(21) Case drain passage
(22) Orifice valve
(23) Signal pressure to the actuator piston
(25) Cutoff spool When the hydraulic system requires a reduction in flow, a signal is constantly sent to load sensing port (15). The signal will reduce pump flow in the hydraulic system.High-pressure oil flows to the margin spool (16) through pump pressure passage (11). The high-pressure oil flows through spool control orifice (17). When the pressure overcomes the force of both load sense signal (15) and margin spring (14). The oil will flow around the cutoff spool (25). The oil flows around orifice valve (22) and into the signal passage to actuator piston (9). Orifice valve (22) will allow oil to flow to actuator piston (9). When the oil pressure behind actuator piston (9) is sufficient, the piston will start to move. The piston rod will push swashplate (2) against bias spring (7). Swashplate (2) will overcome bias spring (7). The angle of swashplate (2) start to decrease and the piston pump will destroke.When the piston pump has destroked to the desired flow, the pump will provide a constant flow. Refer to Section "Constant Flow" in order to view the movement within pressure and flow compensator valve (6) at constant flow. Pump Upstroke
Illustration 4 g01513251
Pump upstroke
(1) Bias spring
(3) Actuator piston
(6) Pressure and flow compensator valve
(11) Swashplate
(14) Margin spring
(15) Load sensing port
(16) Flow compensator spool
(17) Spool control orifice
(20) Plug orifice
(21) Case drain passage
(22) Orifice valve
(23) Signal passage
(25) Cutoff spool When the hydraulic system requires an increase in oil flow, a signal is sent to load sensing port (15). The signal is sent to the load sensing port (15). The pressure at the load sensing port (15) is increased. The combination of the force of margin spring and the increase of pressure at load sensing port (15) will move flow compensator spool (16). The movement of the spool will allow the oil that is behind piston (3) to flow through signal passage (23). The oil will flow around orifice valve (22) and around cutoff spool (25). Flow compensator spool (16) will move in the downward direction. The oil will flow around the spool. The oil will flow through plug orifice (20). The oil continues through passage (21) to the case drain.As the oil is metered