GEAR-RING 2847844 - Caterpillar

Neutralizer Valve
NEUTRALIZER VALVE IN CLOSED POSITION
1. Striker (Stop Assembly). 2. Inlet. 3. Ball check valve. 4. Outlet. 5. Stem. 6. Spring.The neutralizer valve stops the flow of pilot oil to the steering control valve at the end of a complete turn. This stops the steering action before the machine turns against the frame stops.The pilot oil that flows from the hand metering unit (HMU) to the steering control valve must first pass through the right or left neutralizer valve. The oil from the HMU goes into the valve through inlet (2). The oil flows around stem (5) and through outlet (4) to the steering control valve.When the machine is at the end of a complete right turn, striker (1) comes in contact with stem (5) of the right neutralizer valve. It moves the stem until pilot oil can not flow from inlet (2) to outlet (4). This stops the flow of oil across the metering orifices in the main control spool. The steering valve spool will then return to NEUTRAL, and the steering action of the machine stops.Before steering action can start back to the left, oil must flow from the return end of the steering valve spool through the right neutralizer valve. Since stem (5) has the oil stopped, the return oil from the end of the spool must flow past ball check valve (3). This lets the steering valve spool move and the steering action starts.As the machine moves to the left a small amount, striker (1) will move away from the stem. This lets the pilot oil flow around the stem again, and the ball check valve closes.Supplemental Steering System (Optional)
SUPPLEMENTAL STEERING SYSTEM 1. Check valve.2. High pressure filters (screen).3. Flow switch.4. Left neutralizer valve.5. Junction block.6. Hand metering unit (HMU).7. Right neutralizer valve.8. Steering control valve.9. Hydraulic pump.10. Diverter valve.11. Hydraulic tank.12. Left steering cylinder.13. Orifice (and bypass valve).14. Cooler.15. Supplemental steering pump.16. Filter.17. Right steering cylinder.The supplemental steering system has two purposes:(1) To give an oil supply for the steering system if there is a failure of the primary system or if the engine stops when the machine is moving.(2) To add oil to the primary oil flow when the engine rpm is less than 1350 60 rpm and the machine is moving. The Hand Metering Unit will not give manual steering when the engine is stopped. Steering with a dead (stopped) engine can be done only when the Supplemental Steering System is installed.The main components for the supplemental steering system are supplemental steering pump (15), diverter valve (10), and flow switch (3). Check valve (1) is also added with the supplemental system.Supplemental steering pump (15) is a ground driven pump; it is turned as long as the machine moves. The pump gets its power from the output transfer gears of the transmission.When the engine is running, one of the large sections of primary steering pump (9) sends pressure oil through check valve (1) and filter (2) to steering control valve (8).