COUPLER 2672347 - Caterpillar

Illustration 1 g01045583
(1) Diesel engine (2) Pump drive gearbox (3) ECM manifold (4) Drive pump (two) (5) Charge pump (two) (6) Drive motor (two) (7) Final drive and parking brake unit (two)Diesel engine (1) is the source of the mechanical power. Power flows from the diesel engine to the tracks through the hydrostatic drive system.The diesel engine transfers power from the engine flywheel to pump drive gearbox (2). The pump drive gear box distributes the power between the two drive pumps (4) and the implement pump.Drive pumps (4) are variable displacement piston pumps. The displacements of the drive pumps are controlled by charge oil from the steering valves in ECM manifold (3). The steering valves are electrically controlled by the power train ECM. The power train ECM responds to inputs from the operator controls. Each drive pump forms a drive loop with a drive motor (6). Drive motors (6) are variable displacement piston motors.A charge pump is mounted to each drive pump. Charge pumps (5) supply oil to the drive loops and the ECM manifold.Charge oil is supplied to the following components:
Steering Valves
Control Valves for Pump Actuators
Parking Brakes
Makeup Valves for the Drive LoopsThe drive pumps send oil in order to turn drive motors. The drive motor displacements are controlled by internal servo valves, which sense both the forward and reverse charge system pressures within the ECM manifold. The drive motors convert the hydraulic power back to mechanical power by turning final drive and parking brake units (7) .The final drive and parking brake units use one standard gear arrangement and one planetary gear arrangement for a double speed reduction. These speed reductions increase the torque to the tracks. The sprockets on the final drives transfer mechanical power to tracks that drive the machine.Steering is accomplished by changing the pump flows and/or motor displacements. This difference will allow one track to rotate faster than the other track. If the operator demands a sharp turn, flow from one of the drive pumps will reverse. This will cause the corresponding drive motor to turn in the opposite direction. This reverses one of the tracks, while the other track continues to rotate forward.