US 12,103,667 B2
EHA system for lifting/lowering landing gear
Shogo Hagihara, Hyogo (JP); and Takaaki Onishi, Hyogo (JP)
Assigned to SUMITOMO PRECISION PRODUCTS CO., LTD., Hyogo (JP)
Appl. No. 17/911,811
Filed by SUMITOMO PRECISION PRODUCTS CO., LTD., Hyogo (JP)
PCT Filed Dec. 8, 2020, PCT No. PCT/JP2020/045722
§ 371(c)(1), (2) Date Sep. 15, 2022,
PCT Pub. No. WO2021/186808, PCT Pub. Date Sep. 23, 2021.
Claims priority of application No. 2020-046627 (JP), filed on Mar. 17, 2020.
Prior Publication US 2023/0174222 A1, Jun. 8, 2023
Int. Cl. B64C 25/22 (2006.01); F15B 15/20 (2006.01)
CPC B64C 25/22 (2013.01) [F15B 15/20 (2013.01)] 10 Claims
OG exemplary drawing
 
1. An electro hydrostatic actuator (EHA) system for lifting or lowering a leg of an aircraft, comprising:
a hydraulic circuit including a hydraulic actuator attached to the leg to lift or lower the leg, at least one electric hydraulic pump configured to discharge hydraulic fluid supplied to the hydraulic actuator, and a hydraulic path connecting the hydraulic actuator and the electric hydraulic pump to each other;
a pressure sensor configured to output a measurement signal corresponding to a pressure of the hydraulic fluid in the hydraulic circuit during operation of the electric hydraulic pump;
a temperature sensor configured to output a measurement signal corresponding to a temperature of the hydraulic fluid; and
a control unit configured to output a control signal for operating the electric hydraulic pump to the electric hydraulic pump,
wherein:
the hydraulic circuit includes a pressure increasing element configured to increase the pressure of the hydraulic fluid discharged from the electric hydraulic pump,
the control unit performs health monitoring regarding performance of the electric hydraulic pump based on the pressure of the hydraulic fluid based on the measurement signal of the pressure sensor, the temperature of the hydraulic fluid based on the measurement signal of the temperature sensor, and a speed of the electric hydraulic pump during operation of the electric hydraulic pump,
the pressure increasing element is the hydraulic actuator, and
the control unit:
calculates an actual discharge flow rate of the electric hydraulic pump based on the pressure of the hydraulic fluid, the temperature of the hydraulic fluid, and the speed of the electric hydraulic pump during leg lifting by the hydraulic actuator, a time required for the leg lifting by the hydraulic actuator, and an amount of the hydraulic fluid required for the leg lifting by the hydraulic actuator, and
calculates a volumetric efficiency of the electric hydraulic pump from the calculated actual discharge flow rate and an ideal discharge flow rate of the electric hydraulic pump determined from the speed of the electric hydraulic pump.