Patent ID: 9422052
Filing Date: 2016-08-23
CPC Classification: B64C,F15B,Y02T

Claim Text:
1. An electro hydrostatic actuator system for retracting/extending a landing gear of an aircraft, comprising: a plurality of hydraulic actuators configured to sequentially receive, for operation thereof, a supply of operation oil in retraction or extension of the landing gear; a plurality of hydraulic supply sources provided in parallel to each other such that the operation oil is supplied to each hydraulic actuator and the plurality of hydraulic supply sources configured to be joined together; a plurality of switching valves provided in parallel to each other on a supply path that connects the hydraulic actuators to a junction where the hydraulic supply sources are joined together and configured to selectively supply the operation oil to the hydraulic actuators; and a controller configured to sequentially operate the hydraulic actuators by controlling the hydraulic supply sources and the switching valves, wherein each hydraulic supply source includes the hydraulic supply sources together supply the operation oil sequentially to the hydraulic actuators in a normal state of the hydraulic supply sources, when at least one of the hydraulic supply sources is failed, at least one hydraulic supply source other than the failed one of the hydraulic supply sources supplies the operation oil sequentially to the hydraulic actuators, the hydraulic supply sources provided in parallel to each other each include a check valve arranged downstream of the hydraulic pump and upstream of the junction, and each check valve has no pilot lines and is configured to prevent the operation oil from flowing from the junction toward the hydraulic pump.