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| Illustration 1 | g06216248 |
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Control Valve Stack (1) Inlet Manifold (2) Bowl Control Valve (3) Ejector Control Valve (4) Apron Control Valve (5) Outlet Manifold (6) Solenoid Valve | |
Three implement control valves are mounted together in the valve stack: bowl control valve (2), ejector control valve (3), and apron control valve (4).
Inlet manifold (1) is mounted to the rear of the valve stack. The inlet manifold contains the implement lockout solenoid valve, load sense duplicating valve, and load sense relief valve.
Outlet manifold (5) is mounted to the front of the valve stack. the outlet manifold contains the margin pressure relief valve.
The implement control valves are activated by proportional solenoids (6). A solenoid is at both ends of each control valve. The solenoids control the pilot oil that shifts the valve spools. The solenoids are activated by electrical signals from the implement ECM. The electrical signals are proportional to the direction and the amount of movement of the implement control levers.
The apron control valve in the stack does not have a shuttle valve, all other control valves have a shuttle valve. The shuttle valves work together to ensure that the highest pressure that is commanded by a single control valve is sent as the signal to the pump compensator valve.
The spools of the implement control valves are shifted by pilot oil. The flow of pilot oil to the end of the control valve spools is controlled by a proportional solenoid. Every control valve has a solenoid on each end of the spool.
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| Illustration 2 | g03339665 |
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Solenoid valve (de-energized solenoid) (1) Spring (2) Valve spool (3) Passage to hydraulic oil tank (4) Passage from pilot supply oil (5) Passage from pilot chamber (BB) Cutaway section (CC) Component surface (FF) Activated component (GG) Tank pressure (RR) First pilot pressure reduction | |
When an implement is in the HOLD position, both solenoids on the implement control valve are de-energized. When the solenoid is de-energized, spring (1) forces valve spool (2) upward. In this position, pilot supply oil in passage (4) is blocked. The oil that is from the end of the control valve spool drains through passage (5). The oil flows around valve spool (2) and the oil returns to the hydraulic tank through passage (3).
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| Illustration 3 | g03339667 |
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Solenoid valve (energized solenoid) (1) Spring (2) Valve spool (3) Passage to hydraulic oil tank (4) Passage from pilot supply oil (5) Passage to pilot chamber (BB) Cutaway section (CC) Component surface (FF) Activated component (GG) Tank pressure (RR) First pilot pressure reduction | |
When an implement is activated, the solenoid on one end of the implement control valve is energized. The solenoid forces valve spool (2) downward. In this position, passage (3) to passage (5) is blocked.
Passage (4) is open and pilot supply oil flows around valve spool (2) to passage (5). Pilot oil from passage (5) exerts pressure on the end of the control valve spool and the spool shifts.
The solenoid is a proportional solenoid. The solenoid moves valve spool (2) downward by an amount that is proportional to the amount of movement of the implement control lever. When valve spool (2) is pushed down further, passage (4) is opened more. More pilot oil is allowed into passage (5). The implement control spool shifts proportionally to the pilot oil pressure.