PISTON 3818291 - Caterpillar

Illustration 1 g00784175
Schematic for the Front Wheel Assist (1) Left motor for the front wheel assist (2) Right motor for the front wheel assist (3) Return line (4) Flow regulators (5) Check valves (6) Solenoid valve (7) Relief valve (8) Control manifold (9) Auxiliary pump (10) Supply line (11) Return line (12) Case drain lineThe oil is supplied to the front wheel assist hydraulic system by auxiliary pump (9). The auxiliary pump receives oil from supply line (10) .The oil flows from the pump to control manifold (8). The manifold controls the flow and pressure to motors (1) and (2). The flow is blocked by solenoid valve (6). This causes the oil pressure to increase. The oil travels to relief valve (7) and passes through the pilot line. As the oil pressure increases, the relief valve spring is forced open and oil flows back to the front return manifold through line (11). Therefore, no oil is sent to the motors and the front wheel assist does not engage.If the front wheel assist hydraulic system is engaged, the solenoid on valve (6) is energized and the valve allows oil from auxiliary pump (9) to flow through the valve.After solenoid valve (6), the oil passes through the flow regulators (4) and check valves (5). The flow regulators and the check valves control the flow to the motors. The flow regulators and the check valves ensures that both motors receive steady, equal flow.The oil then travels to motors (1) and (2). The case drain oil for the motors is supplied due to the normal oil loss from the main line. The case drain oil is then sent through case drain lines (12) for the motors and the pump to the front return manifold. The rest of the oil passes through the motor and the oil rotates the front wheels. The oil then returns to the front return manifold through return line (3).