BODY-OIL PUMP 1129596 - Caterpillar

Illustration 1 g00793131
Lower section of control valve (5) Accumulator (16) Line
Illustration 2 g00793121
(3) Pilot manifold (5) Accumulator (16) Line (17) Passage (19) Inlet port (20) Pressure oil chamber (21) Bowl (22) Bladder (23) Gas chamber (29) Check valvePilot oil that passes through pilot filter (11) enters port (16) in pilot manifold (3). The pilot oil then opens check valve (29) and the oil goes through passage (17) to hydraulic activation control valve (4). The oil then goes to the pilot control valves for swing or implement operation or for travel operation.The accumulator always stores the pilot pressure oil that is sent from the pilot control valve. At times, the pilot system needs more oil for combined operations than the amount that is provided by pilot pump flow. Also, implements may need to be lowered when the engine is stopped. At these times, the pilot pressure oil that is stored in the accumulator is provided for shifting the stems in the main control valve.In the accumulator, gas chamber (23) is covered with bladder (22). Nitrogen gas is compressed within the gas chamber. The pilot oil in line (16) opens check valve (29) and the oil enters pressure chamber (20) through inlet port (19). The pilot oil then compresses the gas in chamber (23) via bladder (22) in order to store the oil. Check valve (29) prevents the oil in the accumulator from flowing back to line (16).