Volvo EC460B - Boom Down Operation

Boom down operation
1. Neutral
2. Joystick signal(BD) ON
- Spool move and close center passage.
3. Oil supplied to the small chamber and return oil try to return to tank
4. 4pc1 oil make passage to the pilot check valve
5. Pilot check valve open and oil in the back side of the holding valve can be released.
6. Holding valve open
7. Regeneration
- Return oil go through the spool and open back-pressure check valve then return to tank. Build-up return
pressure.
- When supply pressure is low,internal check valve can be open and make passage to the supply side.
- A small amount of oil go to the center passage through the boom regeneration pilot check valve to
reduce the amount of pump flow.
8. Boom down + Travel
- The boom regenration pilot check valve close the passage to the center passage to increase the amount
of pump flow.
Picture text:
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