RAIL AS 6G8160 - Caterpillar

Illustration 1 g06071573
Hydraulic Schematic ZERO OFFSET
(1) Steering priority valve
(2) Steering manifold
(3) Shuttle valve
(4) Counterbalance valve
(5) Steering cylinder
(6) Counterbalance valve
(7) Offset cylinder
(8) Offset priority valve
(9) Warm-up valve
(10) Filter
(11) From steer charge pump
(12) Steering shunt valve
(13) Flow control valve
(14) Main relief valve
(15) To charge filter inlet
(16) Steering control valve
(17) Shuttle valve
(18) Shuttle valve
(19) Offset control valve
(20) Shuttle valveThe drum offset system and the steering system are both controlled by components contained within steering manifold (2). The steering system is controlled by steering control valve (16). The drum offset system uses the steering control valve and offset control valve (19) to control the drum offset while maintaining a constant steering angle. The drum offset system and steering system operate independently.Note: The following discussion of the drum offset system assumes that the machine is not steering. Refer to "Steering System" for additional information about the components and controls of the steering system.When the engine is running, flow from steer charge pump (11) is sent to port "P" of steering manifold (2). Supply oil passes through filter (10) and is directed to the following locations:
Steering priority valve (1)
Offset priority valve (8)
Warm-up valve (9)
Steering shunt valve (12)
Flow control valve (13)If differential pressure across filter (10) exceeds 700 kPa (102 psi), a bypass check valve opens.When the solenoid on steering shunt valve (12) is energized, the steering system and drum offset system are enabled. When the parking brake is applied, the steering system and the drum offset system are disabled. In this case, the shunt valve is not energized and directs all oil flow to charge filter inlet (15).Flow control valve (13) is a load-sensing valve. The valve compares hydraulic pressure supplied to steering manifold (2) with the highest pressure demand being placed on the steering system and drum offset system. When the machine is not being steered, the solenoid on steering control valve (16) is not energized. When the drum offset is not operated, offset control valve (19) is not energized. In both cases, the spool in the flow control valve continuously shifts and directs the supply oil to charge filter inlet (15).If steering cylinder (5) or offset cylinder (7) experience a shock load, the check valve in the low-pressure side of the affected cylinder opens. As the valve opens, oil to enter the low-pressure side of the cylinder preventing cylinder cavitation. Counterbalance valves (4) and (6) limit the maximum pressure in the cylinders to 21000 kPa (3046 psi).The steering system main relief valve (14) limits the maximum pressure in the steering and the drum offset system to 19300 kPa (2799 psi).
Illustration 2 g06071564
Hydraulic Schematic RIGHT OFFSET
(1) Steering priority valve
(2) Steering manifold
(3) Shuttle valve
(4) Counterbalance valve
(5) Steering cylinder
(6) Counterbalance valve
(7) Offset cylinder
(8) Offset priority valve
(9) Warm-up valve
(10) Filter
(11) From steer charge pump
(12) Steering shunt valve
(13) Flow control valve
(14) Main relief valve
(15) To charge filter inlet
(16) Steering control valve
(17) Shuttle valve
(18) Shuttle valve
(19) Offset control valve
(20) Shuttle valveWhen the drum offset right switch is pressed, the machine ECM energizes solenoids on steering control valve (16) and offset