TRANSMISSION AR 2482036 - Caterpillar

Main Hydraulic Schematic
Illustration 1 g06004413
(1) Left travel motor
(2) Right travel motor
(3) Swing motor
(4) Stick cylinder
(5) Boom cylinders
(6) Pressure sensor (boom head end)
(7) Bucket cylinder
(8) Pilot control valve (travel)
(9) Swivel
(10) Travel pressure switch
(11) Main control valve
(12) Pilot control valve (swing and stick)
(13) Pilot control valve (boom and bucket)
(14) Main relief valve
(15) Pressure sensor (idler pump)
(16) Pressure sensor (drive pump)
(17) Pressure reducing valve for boom priority
(18) Bypass check valve
(19) Oil cooler
(20) Slow return check valve
(21) Pressure sensor (boom down control)
(22) Implement pressure switch
(23) Pressure sensor (swing control)
(24) PRV for boom regeneration
(25) Travel speed solenoid valve
(26) Swing brake solenoid valve
(27) Valve
(28) Hydraulic activation solenoid valve
(29) Accumulator
(30) Drain filter
(31) Pilot manifold
(32) Pilot filter
(33) Pilot relief valve
(34) Hydraulic tank
(35) Drive pump
(36) Pilot pump
(37) Idler pump
(38) Proportional reducing valve (power shift pressure)
(39) Negative Flow Control ValveHydraulic Pump Flow and Pressure Control System
Illustration 2 g06010166
Pump compartment
(35) Drive pump
(36) Pilot pump
(37) Idler pump
(40) Outlet line (idler pump)
(41) Outlet line (drive pump)This machine is driven and controlled by the following systems.
The main hydraulic system controls the cylinders, the travel motors, and the swing motor.
The pilot hydraulic system supplies oil to the main pumps, the main control valve, the swing brake, and the travel motors.
The Machine ECM controls the outputs of the engine and pump.The main hydraulic system delivers oil flow from idler pump (37) and drive pump (35) in order to control the following components: bucket cylinder (7), stick cylinder (4), boom cylinders (5), right travel motor (2), left travel motor (1) and swing motor (3).
Illustration 3 g06008286
Control valve
(14) Main relief valve
(42) Left side of the control valve body
(43) Right side of the control valve bodyIdler pump (37) and drive pump (35) are variable displacement piston pumps. The performance of both pumps is equal.Drive pump (35) is directly connected to the engine by a flexible coupling. The drive pump delivers oil to the right side (43) of the control valve body of the main control valve. Idler pump (37) is mechanically connected to the drive pump through gears. The idler pump delivers oil to the left side (42) of the control valve body of the main control valve. Pilot pump (36) supplies oil to the pilot hydraulic system. Pilot pump (36) is directly connected to drive pump (35) by a coupling. All engine output is used to drive these three pumps.As the load pressure increases during working conditions, the delivery pressure increases and the oil flow rate decreases. The hydraulic horsepower remains constant even though the delivery pressure and the flow rates change. The hydraulic horsepower isapproximately identical to the engine horsepower.When no work is being performed, pump oil flows through main control valve (11) back to hydraulic tank (34). The main control valve sends a negative flow control signal to each main pump regulator in order to destroke the pump to the minimum output flow.If an operation is being performed, main control valve (11) directs pump oil to the respective cylinders (boom, bucket, and stick) and/or motors (swing and travel). Main control valve (11) contains numerous valve stems, passages,