SOLENOID AS 3712272 - Caterpillar

Illustration 1 g03325822
(1) Hydraulic pedal
(2) Line for work tool (Return)
(3) Line relief valve
(4) Line for work tool (Supply)
(5) Proportional solenoid valve for negative flow control
(6) Main control valve
(7) Auxiliary control valve
(8) Attachment control valve
(9) Line relief valve
(10) Machine ECM
(11) Pilot manifold
(12) Idler pump
(13) Pilot pump
(14) Drive pump
(15) Hydraulic tank
(16) Filter (if equipped)
Illustration 2 g01243522
Hydraulic pedal
System 3 Prime is used for work tools that require pressurized hydraulic flow in one direction.The work tool is operated by hydraulic pedal (1) which is located on the right side of the travel pedals.Pilot pump (13) supplies oil to pilot manifold (11). When the hydraulic activation lever is moved to the UNLOCK position, pilot oil flows from pilot manifold (11) to hydraulic pedal (1). When hydraulic pedal (1) is depressed to the FORWARD position, pilot oil flows to both auxiliary control valve (7) and to attachment control valve (8). The pilot oil will shift the spool in of the valves to the DOWNWARD position. This allows oil from drive pump (14) to flow through attachment control valve (8). This also allows oil from idler pump (12) to flow through the auxiliary control valve (7). The hydraulic oil from the two pumps combines after the oil passes through both valves. The pump oil flows through the line for the work tool (4) to the work tool. Return oil flows through the line for the work tool (2) back to hydraulic tank (15).The machine ECM sends a signal to the proportional solenoid valve for negative flow control (5). Negative flow control pressure in the center bypass passage is blocked when the valve spools shift DOWNWARD. The machine ECM has programmed parameter values "NAME", "MAX DIAL", and "MIN DIAL" for flow and pressure for the work tool. The machine ECM calculates the negative flow control pressure that will be supplied to the pump regulator. The negative flow control pressure forces the swashplate in drive pump (14) and idler pump (12) to the correct angle to limit the flow and pressure to the work tool.