EDGE AS- 2088866 - Caterpillar

Illustration 1 g00855295
Piston Pump (Hydraulic Fan) (1) Housing. (2) Swashplate. (3) Piston. (4) Cylinder barrel. (5) Spring. (6) Drive shaft. (7) Retraction plate. (8) Control piston. (9) Valve plate. (10) Head.The variable displacement piston pump is used to supply hydraulic oil to the hydraulic fan motor. The movement of pistons (3) in the cylinder barrel (4) pulls a vacuum. The vacuum between the piston and the cylinder barrel pulls oil into the pump from the hydraulic tank. The hydraulic oil is pressurized in the pump. The hydraulic oil is then forced to the hydraulic motor in order to rotate the fan.When drive shaft (6) rotates, hydraulic oil from the tank is pulled into pump head (10) through the inlet passage. The oil then flows from the inlet passage through inlet passages in valve plate (9). Oil is then pulled into the openings of cylinder barrel (4). The hydraulic oil in the cylinder barrel is rotated. As the rotating group is turned the oil is pressurized by pistons (3) in cylinder barrel (4). The cylinder barrel rotates over the outlet passage in valve plate (9). The hydraulic oil is then forced out of the pump discharge port.Each piston (3) inside cylinder barrel (4) is held against swashplate (2) by retraction plate (7). Swashplate (2) can be at any angle between the maximum angle and the neutral angle.As shaft (6) rotates, pistons (3) follow the angle of swashplate (2). The angle of the swashplate controls the in and out movement of the pistons in cylinder barrel (4) .The angle of swashplate (2) determines the amount of oil that is drawn into each cylinder of the cylinder barrel (4). As cylinder barrel (4) rotates, the swashplate angle pushes pistons (3) back into cylinder barrel (4). Pistons (3) will then push oil out of cylinder barrel (4). The oil then flows through the outlet passages of valve plate (9) . Swashplate (2) can be at any angle between the neutral angle and the maximum angle. The neutral angle is perpendicular with drive shaft (6). When swashplate (2) is at the neutral angle, pistons (3) do not move in and out of rotating cylinder barrel (4). Therefore, no oil is drawn into the pump and no oil is pushed out of the pump. The pump has zero displacement and zero flow.When swashplate (2) is at the maximum angle, pistons (3) move in and out of cylinder barrel (4). The in and out movement of pistons (3) allows the maximum amount of oil to be drawn in to cylinder barrel (4), and the pump will produce the maximum displacement.The swashplate angle is controlled by control piston (8). The movement of the control piston (8) is regulated by oil pressure from the pressure and flow compensator valve.
Illustration 2 g00796639
Pressure and Flow Compensator Valve (11) Flow compensator spool. (12) Spring. (13) Adjustment screw. (14) Pressure cutoff spool. (15) Passage for the discharge of the pump. (16) Passage to destroke piston. (17) Drain to tank. (18) Spring. (19) Adjustment