5. EH (electro hydraulic) CONTROL BLOCK STRUCTURE 1) 10-4 10-5 10-6 Proportional pressure reducing valve 10-1 10-2 10-3 P DS T 1 2 3 Filter screen 4 5 6 EH17 EH20 EH19 EH22 EH21 EH18 P T DS ( ) : 2-spool 5 (3) 3 (2) 1 4 6 (4) Hydraulic circuit 2 (1) 760F6WE33 2) OPERATION The proportional pressure reducing valve (10-1~6) is a direct-acting spool-type valve. When de-energized, port 2 is closed and port 1 (delivery) is connected to port 3 (tank). When the inlet pressure fluctuates it provides an almost constant outlet pressure-depending on the energization of the coil.
When the control current increases, the coil solenoid exerts a force on the control piston which is proportional to the control current and thereby defines the regulated pressure at port 1. This setting is proportional to the control current. Pressures at tank port 3 are additive to the set pressure. If, as a result of external factors, the pressure at port 1 rises above the preset pressure, the valve opens from port 1 to tank port 3. 1 3 2 3 2 1 7809A6WE33 6-21 10-4 10-1 10-3(2) 10-2(1) Port Size 1 ~ 6 9/16-18UNF DS P,T 9/16-18UNF 3/4-16UNF