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| Illustration 1 | g00554597 |
Right Side View (1) Pilot/brake pump. (2) Implement pump. (3) Electrohydraulic control. (4) Implement electronic control module (ECM). (5) Main control valve. (6) Lift cylinder. (7) Hydraulic fan motor. (8) Fan reversing valve ( 836G). (9) Thermostatic valve. (10) Hydraulic fan pump. (11) Hydraulic tank. (12) Pilot oil relief valve. (13) Tilt and tip cylinder ( 834G). | |
The implement hydraulic system is composed of the following systems: the implement electronic control system, the pilot hydraulic system, the main hydraulic system and the hydraulic fan system.
Hydraulic tank (11) is common to all of the systems.
The basic operation of the hydraulic system works in the following manner.
The operator turns the key start switch in order to start the machine. The implement pump (2) and the pilot/brake pump (1) supply hydraulic oil for the implement system.
The operator enables the implement pilot system with the implement lockout switch that is mounted on the hydraulic electronic control (3). When the pilot system is enabled, the hydraulics are ready to operate.
When the operator moves the control lever (3) a signal is sent to the electronic control module (4). The ECM (4) sends a signal to the appropriate solenoid valve on the implement control valve (5). The signal activates the solenoid valve in order to vent pilot oil from the pilot control actuator.
When the pilot oil is vented from the pilot control actuator, the spool in the main control valve (5) will shift. When the spool shifts oil that flows from the main implement pump (2) will flow to the respective hydraulic circuit.
When you change the position of the control lever (3) the signal that is sent to the ECM (4) will also change. The ECM will send a corresponding signal to the solenoid on the main control valve (5). The change of signal will result in a change of position for the spool in the main control valve.
Implement Electronic Control System
The implement electronic control system performs the following functions:
- The implement electronic control system electronically controls the pilot control actuators of the pilot hydraulic system.
- The implement electronic control system allows communication between the electronic control modules.
- The implement electronic control system displays information to the operator.
The implement electronic control system is made up of the following components: the electrohydraulic control (3), the implement electronic control module (4), Caterpillar data link, Caterpillar Monitoring System, pilot on/off solenoid valve and pilot control actuator.
Reference: For additional information on the implement electronic control system, refer to System Operation, "Implement Electronic Control System" for your machine.
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| Illustration 2 | g00689695 |
Hydraulic Schematic (1) Lift cylinder. (2) Tip cylinder ( 834G). (3) Tilt and tip cylinder ( 834G). (4) Pilot-operated check valve. (5) Rod end line relief valve for the tilt cylinder ( 834G). (6) Rod end line relief valve for the lift cylinder. (7) Head end line relief valve for the tilt cylinder ( 834G). (8) Rod end line relief valve for the tilt/tip cylinder ( 834G). (9) Head end line relief valve for the tilt/tip cylinder ( 834G). (10) Main control valve. (11) Pilot control actuator for lowering. (12) Pilot control actuator for tilt left. (13) Pilot control actuator for tip forward ( 834G). (14) Pilot control actuator for raising. (15) Load check valve. (16) Main relief valve. (17) Pilot control actuator for the tip back position ( 834G). (18) Pilot control actuator for tilt right ( 834G). (19) Combination valve. (20) Implement pump. (21) Pilot relief valve. (22) Hydraulic oil filter. (23) Pilot/brake pump. (24) Hydraulic fan pump. (25) Hydraulic tank. (26) Thermostatic valve. (27) Hydraulic oil cooler bypass valve. (28) Hydraulic oil cooler. (29) Hydraulic fan motor. | |
Pilot Hydraulic System
The pilot hydraulic system provides pilot oil to the main control valve in order to actuate the spools of the main control valve.
The pilot hydraulic system is made up of the following components: the pilot/brake pump (23), the pilot relief valve (21), the hydraulic oil filter (22), the combination valve for pilot supply (19) and the pilot control actuators (11), (12), (13), (14), (17), and (18) .
Reference: For additional information on the pilot hydraulic system, refer to Systems Operation, "Pilot Hydraulic System" for the machine that is being serviced.
Main Hydraulic System
The main hydraulic system supplies hydraulic oil that is used to power the cylinders that move the implements.
The main hydraulic system is made up of the following components: main control valve (10), lift cylinder (1), tip cylinder ( 834G) (2), tilt and tip cylinder ( 834G) (3), main relief valve (16) and implement pump (20) .
The main hydraulic system supplies the force that is necessary to move the blade.
Reference: For additional information on the main hydraulic system, refer to System Operation, "Main Hydraulic System" for the machine that is being serviced.
Hydraulic Fan System
The hydraulic fan system cools the oil that is in the hydraulic system.
The hydraulic fan system is made up of the following components: hydraulic fan pump (24), thermostatic valve (26), hydraulic fan motor (29), hydraulic oil cooler bypass valve (27) and hydraulic oil cooler (28) .
Reference: For additional information about the hydraulic fan system, refer to Systems Operation, "Hydraulic Fan System" for the machine that is being serviced.