SUPPORT-TRUNNION 1189405 - Caterpillar

Illustration 1 g00800903
(1) Pilot operated hydraulic control ( hydrostatic) (2) Left piston motor ( hydrostatic) (3) Right piston motor ( hydrostatic) (4) Piston pump ( hydrostatic) (5) Gear pump (6) Hydraulic tank
Illustration 2 g00869484
(2) Left piston motor ( hydrostatic) (3) Right piston motor ( hydrostatic) (4) Piston pump ( hydrostatic) (5) Gear pump (6) Hydraulic tank The hydrostatic system is a closed loop. The oil is continuously pumped between the piston pump ( hydrostatic) (4) and the piston motors ( hydrostatic) (2) and (3). The hydrostatic system is kept full of oil by the charge system. The gear pump (5) supplies both sections of the piston pump with charge oil.Signal oil flows from the pilot operated hydraulic control ( hydrostatic) (1) to the signal ports on the piston pump. The signal oil causes the actuators in the piston pump to move the swashplates. This causes the piston pump to pump oil to the piston motors.When the piston pump is in the NEUTRAL position only charge pressure will be in the hydrostatic lines. In the NEUTRAL position, no flow is provided to the piston motors. Flow is produced by the stroking of the swashplates in the two sections of the piston pump (3) . If the pilot operated hydraulic control is pushed to the FORWARD position, the swashplates are stroked. The piston pump pumps oil through the lines to the piston motors. The shafts of the piston motors will turn at a rate that is determined by the amount of oil that is flowing to the piston motors. If the pilot operated hydraulic control is moved further into the FORWARD position, the swashplates will stroke further. This causes the pump to pump oil to the motors faster. If the flow rate is faster, the shafts of the motors will turn faster. When the oil flows from the piston motors (2) and (3), the oil returns to the piston pump.