Volvo EC460B - Arm In Operation

Arm-IN operation
1. Neutral
- Holding condition
2. Joystick Arm-IN(AI) ON
- The Arm1 & Arm2 spool block center passage block
- Holding valve spool move to make holding valve free.
3. Load check open and return line is blocked by holding valve.
4. 5pc1 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 line is restricted by arm regeneration valve when supplying pressure is low.
- Internal check open and return line is connecting to supply line.
8. When supplying pressure is high, arm regeneration valve make wide hole for return line to reduce back
pressure.
9. When using Boom-up at the same time.
- Center passge is blocked by boom1-spool
- Arm parallel conflux changeover valve reduce the passage for the summation of flow.
10. When using swing at the same time.
- Center passge is blocked by the swing spool
- The swing priority valve closes the passage to the arm supply side.
- The double check valve for parallel passage is opened and using orifice.
1