LINES GP-TURBOCHARGER OIL 3145069 - Caterpillar

During combined operations of BOOM RAISE and STICK OUT, the pilot oil pressure from pilot control valve (15) for the boom activates pressure reducing valve (30) for boom priority. Pressure reducing valve (30) for boom priority causes oil flow priority to the head end of boom cylinders (1) during this combined hydraulic operation.When the joystick for the stick is moved to the STICK OUT position, a portion of the pilot oil from pilot control valve (44) for the stick flows through pressure reducing valve (30) to stick II control valve (45) . As the joystick for the boom is moved farther from the NEUTRAL position during a BOOM RAISE operation, pilot oil pressure from pilot control valve (15) for the boom increases. This gradual increase in pilot oil pressure causes the spool in pressure reducing valve (30) to gradually shift.A portion of the pilot oil that flows to stick II control valve (45) from pilot control valve (44) for the stick is routed to the hydraulic tank. The pilot oil pressure in pilot line (46) that acts on stick II control valve (45) decreases. Stick II control valve (45) shifts toward the NEUTRAL position. The amount of oil flow from the main pumps to stick cylinders (43) decreases. This causes a greater portion of the oil flow from the main pumps to flow to the head end of the boom cylinders (1) .Since the pilot oil pressure from pilot control valve (15) for the boom directly corresponds to the amount of movement or position of the joystick a gradual change to boom priority occurs. Thus, boom priority is controlled by the position of the joystick for the boom and boom priority automatically activates when the joystick reaches a certain position during a BOOM RAISE operation.Boom Lower
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(1) Boom cylinders (2) Boom lowering control valve (3) Valve (4) Line (oil flow from boom cylinder rod end) (5) Passage (6) Line (oil flow to boom lowering control valve) (7) Manual ball valve (8) Valve (9) Valve (11) Main control valve (15) Pilot control valve (boom) (20) Boom I control valve (22) Load check valve (23) Return passage (25) Pilot line (27) Return passage (28) Parallel feeder passage (31) Drive pump (34) Return line (47) Valve (48) Pilot line (49) Line (50) Center bypass passage (51) Passage (52) Pilot line (53) Port (54) Check valveIntroduction
When the boom is lowered, oil from drive pump (22) is supplied to boom cylinders (1) through control valve (20) .Control valve (20) contains a regeneration circuit for check valve (15) . When the control lever is moved to the BOOM LOWER position, check valve (15) is forced open. Oil from the head end of cylinders (1) flows to the rod end of cylinders (1) . During a boom lower operation, the regeneration circuit shares oil from drive pump (22) with the other implement functions.Boom Lower
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Control valve BOOM LOWER (boom I) (22) Load check valve (23) Return passage (28) Parallel feeder passage (50) Center bypass