Graphics

3254 Sharpening stone to the right Solenoid coil (Y62) is energised. The pilot spool of solenoid coil (Y62) opens the ball against the pressure in port (P1). Volume flow flows from port (P1) via the ball to port (B) and continues to the right connecting rod end of the sharpening stone movement hydraulic cylinder (341). The return flow coming from the left-hand connecting rod end of the sharpening stone cylinder (341) lifts the pilot spool of the solenoid valve (Y61) and thus returns to the tank. See overall circuit diagram. Sharpening pressure limitation The pressure limitation for sharpening is set to approx. 120 bar. Setting is carried out by using a special valve insert with a relatively large cross-section at the conical seat. The hydraulic force acts on the conical seat of the valve insert and consequently against the electromagnetic force. At a pressure of 120 bar, the conical seat of the valve insert opens because the electromagnetic force is not sufficient any more. The oil pressure is relieved to the tank.