Drive system for aircraft landing gear

Patent metadata

Field	Value
Publication number	US-2017106974-A1
Application number	US-201515129262-A
Country	US
Kind code	A1
Filing date	Mar 31, 2015
Priority date	Apr 1, 2014
Publication date	Apr 20, 2017
Grant date	—

Abstract

A method of engaging a drive system with a rotating wheel of an aircraft landing gear is disclosed. A motor is operated to apply torque to a pinion so the pinion rotates and moved from a neutral position to a contact position in which it contacts a rotating driven gear at an initial contact time, the rotating driven gear being mounted to a rotating wheel of an aircraft landing gear. After the initial contact time the pinion is moved further to a meshing position where the pinion meshes with the driven gear. A centre-to-centre distance between the pinion and the driven gear reduces as the pinion moves to the contact position and to the meshing position. The driven gear contacts the pinion in a series of impacts as the pinion moves from the contact position to the meshing position, each impact induces a spike in electromotive force or angular velocity at the motor.

First claim

1 . A method of engaging a drive system with a rotating wheel of an aircraft landing gear, the method comprising operating a motor to apply torque to a pinion so the pinion rotates; moving the pinion from a neutral position to a contact position in which it contacts a rotating driven gear at an initial contact time, the rotating driven gear being mounted to a rotating wheel of an aircraft landing gear; then after the initial contact time moving the pinion further to a meshing position where the pinion meshes with the driven gear, wherein a centre-to-centre distance between the pinion and the driven gear reduces as the pinion moves to the contact position and to the meshing position, the driven gear contacts the pinion in a series of impacts as the pinion moves from the contact position to the meshing position, each impact induces a spike in electromotive force or angular velocity at the motor, and the method further comprises detecting one of the spikes and operating the motor to vary the torque applied to the pinion in response to the detection of one of the spikes.

2 . The method of claim 1 wherein each impact induces a spike in electromotive force (EMF) at the motor, and the method further comprising detecting one of the EMF spikes and operating the motor to vary the torque applied to the pinion in response to the detection of one of the EMF spikes.

3 . The method of claim 1 wherein the motor applies torque to the pinion via a rotor, each impact induces a spike in angular velocity at the rotor, and the method further comprises detecting one of the spikes in angular velocity and operating the motor to vary the torque applied to the pinion in response to the detection of one of the spikes in angular velocity.

4 . The method of claim 1 further comprising detecting a polarity of the one of the spikes and operating the motor to vary the torque applied to the pinion in accordance with the detected polarity.

5 . The method of claim 1 wherein the pinion has N pinion teeth or rollers which mesh with the teeth or rollers of the driven gear when the pinion is at the meshing position, the pinion and driven gear are rotating at angular velocities ω pinion and ω gear respectively at the initial contact time, and a sync ratio [(ω pinion *N pinion )/(ω gear *N gear )] at the initial contact time is not 1.

6 . The method of claim 5 wherein the sync ratio [(ω pinion *N pinion )/(ω gear *N gear )] at the initial contact time is less than 1.

7 . The method of claim 6 wherein the sync ratio [(ω pinion *N pinion )/(ω gear *N gear )] at the initial contact time is less than 0.98.

8 . The method of claim 7 wherein the sync ratio [(ω pinion *N pinion )/(ω gear *N gear )] at the initial contact time is less than 0.96.

9 . The method of claim 5 wherein the sync ratio [(ω pinion *N pinion )/(ω gear *N gear )] at the initial contact time is less than 0.98 or greater than 1.02.

10 . The method of claim 5 wherein the sync ratio [(ω pinion *N pinion )/(ω gear *N gear )] at the initial contact time is greater than 0.9 and less than 1.

11 . The method of claim 1 wherein if a spike is detected indicating that the pinion speed has been increased, then the motor is operated to reduce the torque by a fixed magnitude; and if a spike is detected indicating that the pinion speed has decreased, then the motor is operated to increase the torque by a fixed magnitude.

12 . A drive system for rotating a wheel of an aircraft landing gear, the drive system comprising a pinion; a driven gear adapted to be mounted to a wheel of an aircraft landing gear; a motor arranged to apply torque to the pinion so the pinion rotates; an actuator which is arranged to move the pinion from a neutral position to a contact position in which it contacts the driven gear at an initial contact time; then after the initial contact time to move the pinion further to a meshing position where the pinion meshes with the driven gear, wherein a centre-to-centre distance between the pinion and the driven gear reduces as the pinion moves to the contact position and to the meshing position, and the driven gear contacts the pinion in a series of impacts as the pinion moves from the contact position to the meshing position, each impact induces a spike in electromotive force or angular velocity at the motor, and wherein the drive system further comprises a sensor arranged to detect the spikes; and a controller which is configured to operate the motor to vary the torque applied to the pinion in response to the detection of one of the spikes by the sensor.

13 . A drive system according to claim 12 , wherein the driven gear has N gear teeth or rollers, and the pinion has N pinion teeth or rollers which mesh with the teeth or rollers of the driven gear when the pinion is at the meshing position; and the drive system further comprises a sensor arranged to detect an angular velocity ω gear of the driven gear; a control loop which is responsive to a velocity demand input to control the motor so that it rotates at an angular velocity determined by the velocity demand input; and a controller arranged to determine the velocity demand input in accordance with a gear ratio (N pinion /N gear ), the angular velocity of the driven gear detected by the sensor, and a predetermined sync ratio, wherein the predetermined sync ratio is chosen so that the pinion is rotating at an angular velocity ω pinion at the initial contact time and [(ω pinion *N pinion )/(ω gear *N gear )] is not 1.

14 . A drive system according to claim 12 , wherein the drive system is supported by a bracket which is rigidly connected to an axle, main fitting or slider part of a landing gear.

15 . A drive system according to claim 14 , wherein the bracket includes two lugs comprising half-moon clamps to permit ready attachment and detachment of the bracket.

Assignees

• Airbus Operations Ltd

Inventors

• Morris James

Classifications

• B64C25/34

  wheeled type, e.g. multi-wheeled bogies · CPC title

• B64C25/405 Primary

  Powered wheels, e.g. for taxing · CPC title

• F16H1/24

  involving gears essentially having intermeshing elements other than involute or cycloidal teeth (F16H1/16 takes precedence) · CPC title

• H02P31/00

  Arrangements for regulating or controlling electric motors not provided for in groups H02P1/00 - H02P5/00, H02P7/00 or H02P21/00 - H02P29/00 · CPC title

• Y02T50/80

  Energy efficient operational measures, e.g. ground operations or mission management · CPC title