HYDRAULIC AR 2316947 - Caterpillar

Construction
Illustration 1 g01338472
Main pumps (1) Proportional reducing valve (power shift pressure) (2) Case drain port (3) Outlet port (drive pump) (4) Outlet port (idler pump) (5) Outlet port (pilot pressure) (6) Port (negative flow control pressure for drive pump) (7) Port (power shift pressure for drive pump) (8) Port (pilot oil to proportional reducing valve) (9) Housing (10) Port (pressure sensor) (11) Inlet port (pilot pump) (12) Port (pressure sensor) (13) Drive pump (14) Inlet port (supply oil from the hydraulic tank) (15) Idler pump (16) Port (power shift pressure for idler pump) (17) Port (negative flow control pressure for idler pump) (71) Pilot pumpThe main pump consists of drive pump (13) and idler pump (15) . The drive pump and the idler pump are contained in an integral housing. Both pumps are variable displacement piston pumps. The drive pump and the idler pump are identical in construction and operation.Supply oil from the hydraulic tank enters inlet port (14) . The single inlet port is common to both pumps. The drive pump delivers oil through outlet port (3) . The idler pump delivers oil through outlet port (4) . Supply oil for pilot pump (71) enters through inlet port (11) . The pilot pump delivers oil through outlet port (5) .Both the drive pump and the idler pump have a regulator as part of the pump control system. The flow control of the pumps is performed by the operation of the regulators. The control system is identical for both pumps.Proportional reducing valve (1) for the power shift pressure is located in the drive pump regulator. The proportional reducing valve is controlled by the machine ECM. The proportional reducing valve controls the power shift signal for both the drive pump and the idler pump.Negative flow control pressure from the main control valve enters the drive pump regulator at port (6) . Negative flow control pressure from the main control valve enters the idler pump regulator at port (17) .Case drain oil from the pump housing flows from port (2) to the case drain filter.Operation
Illustration 2 g01338473
Main pumps (sectional view) (4) Outlet port (idler pump) (9) Housing (14) Inlet port (supply oil from the hydraulic tank) (15) Idler pump (18) Gear (19) Drive shaft (20) Swashplate (21) Drive shaft (22) Gear (23) Plate (24) Retainer (25) Piston slipper (26) Pin (27) Piston (28) Barrel (29) Port plate (30) Passage (70) Port block (71) Pilot pumpGear (22) of drive shaft (21) meshes with gear (18) of drive shaft (19) . Gear (18) and gear (19) have the same number of teeth. Drive shaft (21) of drive pump (13) is connected to the engine by a coupling. When the engine is running, drive shaft (19) and drive shaft (21) rotate at the same speed. Therefore, drive pump (13) and idler pump (15) rotate at the same speed.Pilot pump (71) is directly connected with drive shaft (21) .Barrel (28) contains nine pistons (27) . Piston slippers (25) are connected to pistons (27) by retainers (24)