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| Illustration 1 | g01035982 |
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Steering system in the HOLD position (1) Steering crossover relief valve (2) Steering cylinders (3) Steering metering unit (4) Rotary sleeve (5) Signal purge valve (6) Hydraulic pumps with the pressure and flow compensator valves (7) Hydraulic pump (8) Signal relief valve (9) Signal resolver (10) Hydraulic tank (11) Flow compensator (12) Pressure compensator (13) Steering relief valve (14) Implement relief valve (15) Steering priority valve (16) Combination valve (17) Steering accumulator (If equipped) | |
Oil flows from the hydraulic pumps to combination valve (16). The priority valve (15) which is located inside the combination valve directs oil to the steering circuit. Oil flows through the check valve inside combination valve (16) to the inlet port on steering metering unit (3).
Signal pressure from priority valve (15) is connected to the signal port on steering metering unit (3). Signal oil then passes through an orifice on rotary sleeve (4) and the oil flows to tank (10). Signal oil also flows from priority valve (15) to signal resolver (9).
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| Illustration 2 | g01035976 |
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Steering metering unit in the HOLD position (1) Steering crossover relief valve (2) Steering cylinders (4) Rotary sleeve (18) Anticavitation check valve (19) Check valve (20) Gerotor pump | |
When the steering wheel is turned, pressure and flow from priority valve (15) is directed to steering cylinders (2) through rotary sleeve (4) and metering action of gerotor pump (20). The load sensing line in steering metering unit (3) is internally connected to the pressurized cylinder ports. This action limits the signal pressure from priority valve (15) to actual steering cylinder pressure. Priority valve (15) maintains margin pressure to the inlet port on steering metering unit (3). Signal pressure upstrokes the pump in order to meet the highest pressure and flow demands.
Metered pump oil flows through priority valve (15) to accumulator (17) (If equipped) and to steering metering unit (3).
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| Illustration 3 | g01036023 |
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Steering system during a right turn (1) Steering crossover relief valve (2) Steering cylinders (3) Steering metering unit (6) Hydraulic pumps with the pressure and flow compensator valves (10) Hydraulic tank (16) Combination valve (17) Steering accumulator (If equipped) | |
During a right turn, the gerotor pump supplies oil to relief valve (1) and to steering cylinder (2). Oil flows to the head of the left steering cylinder which forces the cylinder rod outward. Oil also flows into the rod end of the right steering cylinder which forces the cylinder rod inward. Steering cylinders (2) pivot the wheels to the right.
Drain oil is forced out of the opposite ends of steering cylinders (2). The oil flows back through rotary sleeve (4). The oil flows from the rotary sleeve back to tank (10).
Steering crossover relief valve (1) which is located on the front frame contains two line relief valves with anticavitation valves. The anticavitation valves prevent damage from high pressure in the steering circuit that occurs from an outside force. If the oil pressure increases to the relief setting, a line relief valve will open. When the line relief valve is open, the oil from the high pressure side flows to the low pressure side of the system.