SENSOR AS-TEMPERATURE 2457815 - Caterpillar

Main Hydraulic Schematic
Illustration 1 g06225355
(1) Swing motor
(2) Left travel motor
(3) Right travel motor
(6) Travel brake valve (left)
(7) Travel brake valve (right)
(8) Undercarriage extend cylinders
(9) Swivel
(10) Pilot control valve (travel)
(11) Pressure switch
(12) Pressure switch
(14) Main control valve
(16) Pilot control valve (right)
(17) Pilot control valve (left)
(18) Main relief valve
(19) Pressure switch
(20) Slow return check valve
(21) Bypass check valve
(22) Oil cooler
(24) Pilot oil manifold
(25) Travel speed solenoid valve
(26) Swing brake solenoid valve
(27) Valve
(28) Solenoid valve (hydraulic lockout)
(29) Accumulator
(30) Reducing valve (boom priority mode or swing priority mode)
(33) Pilot pump
(34) Drive pump
(35) Idler pump
(36) Pressure sensor (drive pump)
(37) Proportional reducing valve (power shift pressure)
(38) Pressure sensor (idler pump)
(40) Return filter
(41) Hydraulic tank
(42) Drain filter
(43) Pilot relief valve
(44) Pilot filterHydraulic Pump Flow and Pressure Control System
Illustration 2 g06265613
Pump compartment
(33) Pilot pump
(34) Drive pump
(35) Idler pump
(37) Proportional reducing valve (power shift pressure)
(46) Delivery line (drive pump)
(47) Delivery line (idler 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 electronic control system controls the outputs of the engine and pump.The main hydraulic system delivers oil flow from idler pump (35) and drive pump (34) to control the following components: right travel motor (3), left travel motor, (2) and swing motor (1).
Illustration 3 g06265619
Main control valve
(18) Main relief valve
(48) Right control valve body
(49) Left control valve bodyIdler pump (35) and drive pump (34) are variable displacement piston pumps. The performance of both pumps is equal.Drive pump (34) is directly connected to the engine by a flexible coupling. The drive pump delivers oil to the right control valve body (48) of the main control valve. Idler pump (35) is mechanically connected to the drive pump through gears. The idler pump delivers oil to the left control valve body (49) of the main control valve. Pilot pump (33) supplies oil to the pilot hydraulic system. The pilot pump (33) is mechanically connected to idler pump (35) through gears. All engine output is used to drive these three pumps.As the load pressure increases during working conditions, the main pumps increase the delivery pressure and the pumps decrease the flow rate. The hydraulic horsepower remains constant even though the delivery pressure and the flow rates change. The hydraulic horsepower is identical to the engine horsepower.When no work is being performed, pump oil flows through main control valve (14) and into hydraulic tank (41). The main control valve sends a negative flow control signal to each main pump regulator to destroke the pump to the minimum output flow.If an operation is being performed, main control valve (14) directs pump oil to the respective cylinders and/or motors (swing and travel). Main control valve (14) contains numerous valve stems, passages, check valves, and orifices to carry out a single operation or a combined operation. The working pressure of the main hydraulic system is regulated by main relief valve (18).
Illustration 4 g01341379
Cab
(50) Monitor panel
(51)