VALVE GP-PILOT 1938391 - Caterpillar

Illustration 1 g01102068
(1) Swing motor (2) Travel motors (3) Case drain line (4) Case drain line (5) Makeup line (makeup oil to swing motor) (6) Return line (7) Return passage (8) Return line (9) Return passage (10) Main control valve (11) Center bypass passage (12) Negative flow control orifice (13) Negative flow control orifice (14) Case drain line (15) Center bypass passage (16) Return line (17) Slow return check valve (18) Hydraulic oil cooler (19) Left pump (20) Right pump (21) Pilot pump (22) Case drain filter (23) Bypass check valve (24) Hydraulic tank (25) Case drain line (26) Suction line (27) Drain lines for the harvester head (28) Case drain filter (29) Case drain line (30) Case drain line (31) Solenoid valve (harvester head) (32) Return filterThe oil delivery from right pump (20) and left pump (19) enters main control valve (10). The oil then flows to return passage (7) and return line (6) in one of the following manners.When all joysticks and/or travel levers/pedals are in the NEUTRAL position, pump low pressure standby oil from right pump (20) flows through center bypass passage (11) and negative flow control orifice (12) to return line (6). Pump low pressure standby oil from left pump (19) flows through center bypass passage (15) and negative flow control orifice (13) to return line (8) .When any one of the joysticks and/or travel levers/pedals is shifted from the NEUTRAL position, center bypass passages (11) and (15) are blocked. The return oil from the cylinders and/or motors now flows through return passage (9) to return line (8) .The return oil from return line (6) and return line (8) flows through return line (16) and slow return check valve (17) .When the oil temperature is very low, most of the oil is returned through bypass check valve (23) to hydraulic tank (24). The remainder of the oil flows into oil cooler (18) to hydraulic tank (24) .When the oil temperature increases, the rate of oil flow through bypass check valve (23) decreases. This causes the rate of oil flow through oil cooler (18) to increase.Reference: For more information concerning the bypass check valve, refer to Systems Operation, "Bypass Valve (Return)".Case drain oil from right pump (20), left pump (19) and pilot pump (21) flows into case drain line (25). Case drain oil from swing motor (1) and travel motors (2) flows into respective case drain lines (3) and (4). Case drain oil from drain lines for the harvester head (27) flows through case drain filter (28) into case drain line (29). Case drain oil from solenoid valve (31) flows into case drain line (30). The case drain oil from the motors, the harvester head, and the solenoid valve flows through case drain line (14) and combines with the case drain oil from the pumps at case drain line (25). All of the case drain oil from the pumps, motors, harvester head, and the solenoid valve now flows through case drain filter (22) to hydraulic tank