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| Illustration 1 | g00556604 |
Schematic for the High Pressure Steering System (1) Left steering cylinder (2) Right steering cylinder (3) Steering control valve (4) Backup relief valve for the steering pump (5) Steering pilot valve for machines that are equipped with wheel steering (6) Steering crossover relief valve for the steering cylinders (7) Steering control valve spool (8) Case drain oil filter (9) Check valve (10) Steering pilot valve for machines that are equipped with STIC steering (11) Steering pump (12) Hydraulic oil tank (A) Pressure port for the pilot circuit (B) Pressure port for the steering pump | |
Note: The 834G Wheel Tractor and 836G Landfill Compactor are equipped with STIC steering. The 836G Landfill Compactor may be equipped with either STIC steering or wheel steering. Steering pilot valve (5) is for machines that are equipped with wheel steering. Steering pilot valve (10) is for machines that are equipped with STIC steering. Steering pilot valves (5) and (10) are interchangeable in the schematic for the high pressure steering system.
The main components of the high pressure steering system follow: hydraulic oil tank (12), steering pump (11), steering control valve (3), backup relief valve for the steering pump (4), left steering cylinder (1) and right steering cylinder (2) .
Steering pump (11) draws oil from hydraulic oil tank (12). Pressure oil from steering pump (11) flows to steering control valve (3). The oil then flows to spool (7). Spool (7) shifts in order to direct the flow of pressure oil to the steering cylinders. A case drain oil filter (8) is provided in order to filter case drain oil. A bypass check valve (9) allows oil to bypass the filter if the filter is clogged.
If a left turn is required, spool (7) shifts to the left. This allows pressure oil to flow to the rod end of steering cylinder (1). At the same time, pressure oil flows to the head end of steering cylinder (2). This causes the machine to turn to the left.
If a right turn is required, spool (7) shifts to the right. This allows pressure oil to flow to the rod end of steering cylinder (2). At the same time, pressure oil flows to the head end of steering cylinder (1). This causes the machine to turn to the right.
Backup relief valve (4) for the steering pump limits the amount of pressure in the steering system. This helps prevent excessive wear on system components.
If an outside force tries to force the machine to turn, and if valve spool (7) is in the NEUTRAL position, an increase in pressure will occur. The increase in pressure will open steering cylinder crossover relief valve (6). Steering crossover relief valve (6) ensures that the pressure at steering cylinder (1) and at steering cylinder (2) does not exceed the specification.