COVER 9R0796 - Caterpillar

Illustration 1 g01134128
Hydraulic Schematic for the Steering System (1) Left steering cylinder (2) Right steering cylinder (3) Shuttle valve (4) Pressure relief valve for the steering system (5) Unloader spool for the secondary steering system (6) Pressure relief valve for the secondary steering system (7) Secondary steering diverter valve (8) Gear pump for the secondary steering system (9) Oil cooler for the steering and brake systems (10) Check valve for the oil cooler bypass (11) Return screen for the steering system "STRG RTRN FLTR" (12) Pressure switch for the return screen (13) Crossover relief valve (14) Steering control valve (15) Oil screens for the steering pump output "STRG OIL FLTR" (16) Check valves for the steering neutralizer valves (17) Pressure and flow compensator valve (18) Check valve for the steering pump (19) Fluid sampling port (20) Gear pump for the oil cooler circuit (21) Left steering neutralizer valve (22) Right steering neutralizer valve (23) Steering pump (24) Steering pilot valve (25) Steering pump (26) Pressure switch for the oil filter (27) Selector and pressure control valves (28) Pressure switch for the steering system "STRG OIL PRES" (29) Case drain filter for the steering pump "LT or RT STRG CDRN ST" (30) Hydraulic tank for the steering and brake systemsThe steering system provides the high-pressure oil that is needed to turn the machine. The steering pumps also supply oil to the steering pilot system. The steering system uses two variable displacement piston pumps (23) and (25). The steering pumps are load sensing pumps. The pumps are located near the top of the rear pump drive. There is a pressure and flow compensator valve (17) attached to each steering pump. The pressure and flow compensator valves control the amount and pressure of hydraulic oil that is delivered to the steering system from the steering pumps. Pressure and flow compensator valves (17) keep the oil pressure and flow from the steering pumps at a level that is needed in order to fulfill the requirements of the steering system.Steering pumps (23) and (25) draw hydraulic oil from hydraulic tank (30). The case drain oil from the steering pumps flows through case drain filters (29). The case drain filters remove debris from the oil. The filters prevent contamination of the oil that is in the hydraulic tank. Filter bypass switch (26) actuates when the flow of oil through the filter is restricted. Filter bypass switch (26) is monitored by the Vital Information Management System (VIMS). Then, the case drain oil flows to the hydraulic tank for the steering and brake systems.The pressure oil from steering pumps (23) and (25) flows through check valves (18). From the check valves, the pressure oil flows through oil screens (15). The oil screens filter debris from the pressure oil. The screens prevent contamination of the oil that is in the steering system.The pressure oil then flows from oil screens (15) to steering control valve (14). Check valves (18) prevent pressure oil from flowing back to steering pumps (23)