ELECTRO-HYDROSTATIC SERVO-ACTUATOR FOR AIRCRAFTS

摘要

The invention relates to an electro-hydrostatic servo-actuator intended mainly to drive the control surfaces of an airplane, but useful in any field in which the hydraulic drive lacks a separate pressure source, as well as in mountings where accidental oil leaks along the pipes must be prevented. According to the invention, the servo-actuator consists of a reservoir (3), a constant capacity bidirectional gear pump (1) driven by a brushless D.C. motor (6) and driving, in its turn, a piston cylinder (2), by two paths (I and II), where a group of direction valves (4) allows the alternating supply of the two chambers of the cylinder (2) with pressurized hydraulic liquid and another group of valves (7) permits the hydraulic liquid to pass from the specific control path (I or II) of the cylinder (2) which has the highest pressure at a given moment, to a pressure valve (10) which is unique in the system and which limits the maximal pressure to be reached in the two paths (I and II) and where the electric motor (6) is controlled by means of an electric control signal set within a computing block based on some input-output data of the system.