Electrohydraulic propeller governor

摘要

A propeller governor for controlling blade pitch of a variable pitch propeller has a hydraulic control circuit coupled to the propeller to change blade pitch in response to hydraulic pressure. The hydraulic control circuit has a first pressure path configured to adjust blade pitch within a first range of blade pitch, and a second, different pressure path configured to adjust blade pitch within a second range of blade pitch. An electrohydraulic servo valve of the governor is configured to adjust hydraulic pressure in the first pressure path to adjust blade pitch within the first range and to adjust hydraulic pressure in the second pressure path to adjust blade pitch within the second range.

主权项

1. A propeller governor for controlling blade pitch of a variable pitch propeller, the propeller governor comprising:
a hydraulic control circuit coupled to the propeller to change blade pitch in response to hydraulic pressure, the hydraulic control circuit having:
a first pressure path configured to adjust blade pitch within a first range of blade pitch;a second, different pressure path configured to adjust blade pitch within a second range of blade pitch, the first pressure path being a flight pressure path and the second pressure path being a beta pressure path;a pressure source in fluid communication with an electrohydraulic servo valve,a pressure drain having lower pressure than the pressure source, the pressure drain in fluid communication with the electrohydraulic servo valve, anda propeller pitch piston coupled to the propeller to change blade pitch in response to hydraulic pressure, the propeller pitch piston in fluid communication with the electrohydraulic servo valve via the first pressure path;wherein the electrohydraulic servo valve communicates the pressure source to the propeller pitch piston to decrease blade pitch within the first range of blade pitch and communicates the pressure drain to the propeller pitch piston to increase blade pitch within the first range of blade pitch; anda second valve in fluid communication with the first pressure path, in fluid communication with the pressure drain, and coupled to the propeller pitch piston, the second valve configured to allow passage of pressure through the first pressure path when blade pitch is within the first range of blade pitch and vent pressure from the first pressure path when blade pitch is below the first range of blade pitch; and wherein the electrohydraulic servo valve is configured to:
adjust hydraulic pressure in the first pressure path to adjust blade pitch within the first range when the propeller is operated in a flight mode, andadjust hydraulic pressure in the second pressure path to adjust blade pitch within the second range when the propeller is operated in a beta mode.