VALVE GP-PUMP CONTROL 2993932 - Caterpillar

Regulator Operation (Constant Flow)
Illustration 6 g02143648
Pump regulator (constant flow)
(2) Horsepower control spool
(3) Horsepower control sleeve
(6) Negative flow control lever
(7) Pivot pin
(9) Pin (feedback lever)
(10) Negative flow control piston
(11) Maximum angle end of actuator piston
(12) Feedback lever
(15) Actuator piston
(17) Minimum angle end of actuator piston
(21) Swashplate
(22) NFC lever pin
(25) Maximum angle stop
(26) Orifice
(PI) Negative flow control pressure As actuator piston (15) moves, the lower end of feedback lever (12) moves to the left. Feedback lever (12) rotates clockwise with the pin for the feedback lever (9) as the pivot point.The upper end of feedback lever (12) pulls horsepower control spool (2) to the right until the right land on horsepower control spool (2) reaches a balance point between orifices (26) through the horsepower control sleeve (3).Flow to and from the minimum angle end of the actuator piston (17) is metered by horsepower control spool (2) and horsepower control sleeve (3). The angle of swashplate (21) remains constant until NFC pressure (PI) is again changed.Regulator Operation (Flow Increase - Full Upstroke)
Illustration 7 g02143684
Pump regulator (flow increase - full upstroke)
(2) Horsepower control spool
(3) Horsepower control sleeve
(6) Negative flow control lever
(7) Pivot pin
(9) Pin (feedback lever)
(10) Negative flow control piston
(11) Maximum angle end of actuator piston
(12) Feedback lever
(17) Minimum angle end of actuator piston
(21) Swashplate
(22) NFC lever pin
(25) Maximum angle stop
(26) Orifice
(PI) Negative flow control pressure The amount of reduction in NFC signal pressure (PI) determines the amount of pump upstroke. If NFC pressure is reduced to minimum, the pump will upstroke until actuator piston (15) contacts maximum angle stop screw (25).Note: A decrease in power shift pressure will cause an increase in flow from the pump in the same manner as described for a decrease in system pressure, since both power shift pressure and system pressures act on torque control piston (18).Regulator Operation (Flow Decrease - Start of Destroke)
Illustration 8 g02143689
Pump regulator (flow decrease -start of destroke)
(2) Horsepower control spool
(3) Horsepower control sleeve
(5) Torque control lever
(7) Pivot pin
(9) Pin (feedback lever)
(11) Maximum angle end of actuator piston
(12) Feedback lever
(14) Torque control spool
(15) Actuator piston
(17) Minimum angle end of actuator piston
(18) Torque control piston
(26) Orifice
(27) Torque control lever pin
(28) Horsepower control springs
(29) Adjustment screw (first stage of the constant horsepower control)
(30) Adjustment screw (second stage of the constant horsepower control)
(PD) Pump delivery pressure
(PS) Power shift pressure
(CF) Cross sensing control pressure Illustration 8 shows torque control piston (18) and horsepower control spool sections of the pump control valve group with the pump in the upstroked position at the beginning of DESTROKE due to an increase in the load on the system.Pivot pin (7) is fixed to the pump control housing. Torque control lever (5) pivots around pivot pin (7).Adjustment screw for the first stage of constant horsepower control (29) regulates the pressure or point that the pump starts to destroke (large spring adjustment). Adjustment screw for the second stage of constant horsepower control (30) regulates the rate that the pump destrokes (small spring adjustment).Power shift pressure (PS) from the power shift PRV solenoid valve enters the