Function diagram, neutral

Key to diagram

Item Designation Remark

734 Lock-up valve unit (non-return valve) Y9 AUTOPILOT left solenoid coil -

Y10 AUTOPILOT right solenoid coil K Piston -

Description of function

Oil pressure supply The oil pressure required for performing the function is taken from the preloaded working hydraulics system. Autopilot – steering to the left The solenoid coil (Y9) is energised and opens the ball via the pilot spool. Oil flows from P1 to the lock-up valve unit via the ball. The non-return valve (port A) is opened by the oil flow against the spring force and oil flows to the steering cylinder. Before this, the pressure built up pushes the piston (K) towards port (B) and opens the non-return valve (port B). The oil coming from the cylinder return side flows via the open right non-return valve. The return flow lifts the pilot spool of the solenoid coil (Y10) and thus returns to the tank. Autopilot – steering to the right The solenoid coil (Y10) is energised and opens the ball via the pilot spool. Oil flows from P1 to the lock-up valve unit via the ball. The non-return valve (port B) is opened by the oil flow against the spring force and oil flows to the steering cylinder. Before this, the pressure built up pushes the piston (K) towards port (A) and opens the non-return valve of port (A). The oil coming from the cylinder return side flows via the open left non-return valve. The return flow lifts the pilot spool of the solenoid coil (Y9) and thus returns to the tank.

Note: The sealing ring beneath the valve inserts must be replaced upon each assembly as otherwise leaks may occur.