Hydraulic control circuit for controlling fan blade pitch

Abstract

A hydraulic control circuit of a double-acting orientation cylinder to orient fan vanes of a turbojet engine, comprising an oil tank, a variable-displacement axial piston pump including a swash plate controlled by a double-acting control and compensation cylinder comprising a control chamber and a compensation chamber, the pump being supplied by the reservoir and having the outlet thereof configured to be able to be connected, via a supply pipe, to a second chamber of the orientation cylinder, a first chamber of the orientation cylinder being connected to the tank, the chambers of the control and compensation cylinder both being pressurised with a pressure corresponding to the outlet pressure of the pump, and wherein the control and compensation chambers are arranged to increase the tilt of the plate in order to increase the displacement of the pump when the pressurisation pressure of these chambers increases.

Dependencies are inferred from the claim text.