BEARING, MAIN LOWER 62011130115 - Caterpillar

Illustration 1 g00944102
Load Sensing Signal System for 574B Forwarder (1) Steering Metering Pump (2) Steering Priority Valve (3) Combination Valve (4) Solenoid Valve (Cold Start) (5) Pressure Relief Valve (Steering Signal) (6) Pressure Relief Valve (Maximum Signal) (7) Hydraulic Oil Tank (8) Piston Pump (Implement) (9) Piston Pump (Power Train) (10) Implement Control Valve (11) Accumulator (Pilot Oil) (12) Pressure Tap (Piston Pump (Implement) Signal Pressure) (13) Pressure Tap (Piston Pump (Implement) Supply Pressure)When the operator turns the engine start switch, electrical current flows to solenoid valve (4). This activates solenoid valve (4). Solenoid valve (4) blocks signal pressure oil from the brake accumulator charging valve. This assists the starting of the engine by decreasing the load on the engine.When the operator releases the key, current is cutoff to solenoid valve (4) and signal pressure oil flows from the brake accumulator charging valve to the piston pump (implement) (8). The signal upstrokes the pump in order to charge the brake accumulators.When the engine starts, there is no pressure in the load sensing signal system. Piston pump (implement) (8) is stroked to maximum output. As piston pump (implement) (8) begins to turn, the pressure in the signal system increases. Accumulator (11) is charged. The pump strokes to low pressure standby until a function is activated.Accumulator (11) is fully charged by the pilot oil of the signal system. When the engine is stopped, accumulator (11) will stay charged for a period of time. If the boom is in the raised position and the engine stops, the pressurized oil in accumulator (11) will allow the boom to be lowered.Note: The starter key switch must be in the ON position in order to lower the boom when the engine is stopped.Note: Use pressure tap (12) in order to measure the signal pressure. The pressure tap is located on the "LS" port at the end of implement control valve (10) .When the operator uses the steering wheel, steering metering pump (1) sends a load signal to pressure relief valve (5) and priority valve (2). The load signal in the priority valve controls the flow of pressure oil to the steering metering pump.Pressure relief valve (5) limits