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| Illustration 1 | g01207252 |
Hydraulic schematic for the steering system (1) Steering cylinder (2) Line relief and makeup valve for the head end of the steering cylinder (3) Line relief and makeup valve for the rod end of the steering cylinder (4) Steering neutralizer valve for a left turn (5) Steering neutralizer valve for a right turn (6) Implement and steering solenoid (7) Parking brake control valve (8) Spool (9) Load sensing shuttle valve (10) Secondary steering pump (11) Spool (12) STIC steering pilot valve (13) Line to parking brake circuit (14) Primary steering flow switch (15) Spool (16) Steering system relief valve (17) Steering control valve (18) Steering system pressure tap (19) Check valve (20) Check valve (21) Line from lift circuit (22) Secondary steering diverter valve (23) Hydraulic oil cooler (24) Pressure tap for the pilot system (25) Check valve (26) Pilot oil pressure reducing valve (27) Check valve (28) Pilot and braking pump (29) Steering pump (30) Implement pump (31) Breaker relief valve (32) Portable hydraulic quick connect coupler (33) Selector and pressure control valve (34) Line to the brake accumulator charging valve (35) Hydraulic oil filters (36) Hydraulic tank (37) Portable hydraulic quick connect coupler | |
Note: Illustration 1 shows a machine with the secondary steering system. Machines without the secondary steering system will not have secondary steering pump (10), secondary steering diverter valve (22) and primary steering flow switch (14) .
The high pressure circuit provides the high pressure oil for steering cylinder (1) .
With the engine running, oil is drawn from hydraulic tank (36) by steering pump (29). Steering pump (29) supplies oil to steering control valve (17). Oil supplied to steering control valve (17) flows through spool (11) to spool (8) .
When pilot oil moves spool (8) the high pressure oil is directed to steering cylinder (1). When a right turn is made, the pressure oil flows to the rod end of steering cylinder (1). When a left turn is made, the pressure oil flows to the head end of steering cylinder (1) .
Oil displaced from the steering cylinder when a turn is made returns through spool (8) and steering control valve (17) to hydraulic oil cooler (23). The return oil flows through hydraulic oil cooler (23) and hydraulic oil filters (35) to hydraulic tank (36) .
The hydraulic oil cooler has an orifice that bypasses the oil cooler. If the oil is cold or if the oil cooler is blocked, the oil will flow through the orifice and return to the hydraulic tank.