GEAR AND BEARING GROUP 1362884 - Caterpillar

Illustration 1 g00738731
Hydraulic schematic (1) Swing motor (2) Grapple cylinders (3) Boom cylinders (4) Swivel (5) Boom lowering control valves (6) Stick cylinder (7) Bleeder valve (8) Steering valve (9) Stick lowering control valve (10) Stick drift reduction valve (11) Pressure switch (implement or swing) (12) Pressure switch (travel) (13) Boom drift reduction valve (14) Steering valve (15) Main control valve (16) Main relief valve (17) Relief valve manifold (18) Pressure switch (boom raise) (19) Brake valve (20) Brake accumulator (21) Brake valve (22) Pilot control valve (travel) (23) Pilot control valve (swing or stick) (24) Solenoid valve (fine control) (25) Solenoid valve (swing priority mode) (26) Proportional reducing valve (27) Pilot control valve (boom) (28) Upper pump (29) Pilot pump (30) Lower pump (31) Hydraulic activation control valve (32) Pilot control valve (grapple) (33) Pilot control valve (stabilizers) (34) Return filter (35) Oil cooler (36) Return filter (37) Hydraulic tank (38) Pilot filter (39) Generator pump (40) Steering pump (41) Transmission charge pump (42) Generator motor (43) Valve for grapple rotatorPump Pressure
Introduction
Illustration 2 g00797172
Pump compartment (28) Upper pump (30) Lower pumpThis machine is driven and controlled by the following systems.
The main hydraulic system supplies oil to the cylinders and motors of the machine.
The pilot hydraulic system supplies oil to the control circuits.
The electronic control system controls the output from the engine and the pump.The main hydraulic system oil is supplied by upper pump (28) and lower pump (30). Pumps (28) and (30) are variable displacement piston pumps. Pumps (28) and (30) are identical in performance. Upper pump (28) is directly connected to the engine by a flexible coupling. Pumps (28) and (30) are mechanically connected in parallel through gears.Gear type pilot pump (29) supplies oil to the pilot hydraulic system. Gear type pilot pump (29) is directly connected to lower pump (30) by a gear. All engine output is used to drive these three pumps.Each of the main pumps delivers approximately 211 L/min (56 US gpm) of hydraulic oil at no load. The pilot pump delivers approximately 40 L/min (11 US gpm) of hydraulic oil at no load. When a load is placed on the machine, the hydraulic oil is forced into the main hydraulic circuit.When the load increases, the main pumps increase the delivery pressure and the pumps decrease the flow rate. The hydraulic horsepower remains constant even though the oil pressure and the flow rates change. The hydraulic horsepower is approximately identical to the engine horsepower.
Illustration 3 g00797186
Main control valve compartment (16) Main relief valve (44) Right control valve body (45) Left control valve bodyThe oil from upper pump (28) flows into right valve body (44). The oil from lower pump (30) flows into left valve body (45). Main control valve (15) is made up of right valve body (44) and left valve body (45) .When no work is being performed, pump oil flows through main control valve (15) and into hydraulic tank (37). The main control valve sends a negative flow control signal to each main pump