PUMP & MTG GP-CUSHION-HITCH 1569797 - Caterpillar

Note: The charge pump on the upper pump stack provides charge pressure oil for the upper and the lower pumps stacks.
Illustration 4 g00953879
Hydraulic Schematic of the Upper Pump StackIllustration 4 contains the following components that are part of the piston pumps for the left and right auger conveyors: (12) Piston pump (auger conveyor) (13) Swashplate piston (14) Servo control valve (15) Servo control cylinder (16) EDC valve (17) Charge pressure relief valve (18) Reverse relief valve (19) Reverse combination valve (20) Charge pump (21) Reverse makeup check valve (22) Forward relief valve (23) Forward makeup check valve (24) Forward combination valveOperation and Oil Flow
Note: Illustration 5 shows the upper pump stack. The upper pump stack contains the piston pump that provides oil for the right auger motor. The lower pump stack contains the piston pump that provides oil for the left auger motor. The only difference between the upper and lower pump stacks is that the upper pump stack contains the charge pump. The charge pump provides charge pressure oil for the upper and lower pump stacks. The lower pump stack is not shown in this section.Upper Pump Stack (Right Auger Pump)
Illustration 5 shows the oil flow in the forward direction.
Illustration 5 g00944426
Hydraulic SchematicIllustration 5 contains the following components that are part of the piston pumps for the left and right auger conveyors: (12) Piston pump (auger conveyor) (13) Swashplate piston (14) Servo control valve (15) Servo control cylinder (16) EDC valve (17) Charge pressure relief valve (18) Reverse relief valve (19) Reverse combination valve (20) Charge pump (21) Reverse makeup check valve (22) Forward relief valve (23) Forward makeup check valve (24) Forward combination valve (25) Line to oil cooler bypass manifold (26) Right auger motor (27) Line to oil cooler bypass manifold (28) Charge filter (29) Line to oil cooler bypass manifold (30) Line to lower pump stack (31) Solenoid (forward) (32) Solenoid (reverse) (33) Valve envelope (34) Valve envelope (35) Valve envelope (36) Valve envelope (37) Test port (AA) System pressure (AB) Charge pressure (AC) Sump (AD) Activated components (AE) First pressure reduction (AF) Reduced charge pressureSwashplate Control
Note: Unlike the piston pumps for the drag conveyors, the piston pumps for the auger conveyors delivers pressure oil in forward and reverse directions. As a result, the auger conveyor motors can run in forward or reverse.When the machine is started, hydraulic oil is drawn through a suction screen in the hydraulic tank by charge pump (20) . The charge pump sends charge pressure oil to charge filter (28) . Charge pressure oil is then delivered to the upper pump stack at port "M6" and to the lower pump stack through line (30) .Charge pressure oil supplies EDC valve (16) and servo control valve (14) with oil. When solenoid (31) (forward) is energized, valve envelope (33) will move to the right. Because EDC valve (16) is a proportional valve, the amount of oil going through valve envelope (33) will be directly proportional to the amount of input current that is