| 摘要 |
A tandem spool have has left and right spools (16, 18) mounted for longitudinal movement within a valve housing (10, 12, 14). An electric torque motor (20, 22), including a rotor and a stator are arranged to drive the spools via an eccentric coupling arrangement (30). A rotor housing (60, 62) contains hydraulic fluid within which the rotor (52, 54) is immersed, the rotor housing having afluid-retaining wall which passes between the rotor and the stator. Accordingly, the electrical connections to the stator coils do not have to pass through a hydraulic seal, neither is the stator subject to the stress of hydraulic pressure. A linear force motor could be used instead of a torque motor. |
