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| Illustration 1 | g01182973 |
Partial hydraulic schematic (1) Main control valve (2) Pilot control valve (Boom and Bucket) (3) Pilot control valve (Stick and Swing) (4) Main hydraulic pump (5) Pilot pump (6) Pilot manifold | |
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| Illustration 2 | g01270999 |
Operator's compartment (2) Right joystick (Boom and Bucket) (3) Left joystick (Stick and Swing) (8) Left travel lever (9) Right travel lever (11) Blade control lever (12) Pedal for swing boom | |
The flow rate of the pilot pump does not vary as the pump directs oil under pressure to the main control valve. The pressure of the pilot system is regulated by the pilot relief valve.
Pilot oil has the following functions:
Operation of the main control valve - When joysticks (2) and (3) are operated, pilot oil is sent to main control valve (1) . The boom swing is activated by the pedal for swing boom (12) .
Generation of signal pressure - The following operations are carried out by the signal pressure that is generated in the pilot circuit:
- The swing parking brake is released.
- When the implement system is activated during machine travel, the straight travel control valve is activated. This combines the right pump and left pump flow which enables the machine to maintain straight travel.