Landing gear drive system flexible interface

Patent metadata

Field	Value
Publication number	US-2016200426-A1
Application number	US-201414914669-A
Country	US
Kind code	A1
Filing date	Sep 3, 2014
Priority date	Sep 5, 2013
Publication date	Jul 14, 2016
Grant date	—

Abstract

Known autonomous taxi systems for aircraft include a rigid connection between the aircraft wheel and a gear which is used to drive it. Such arrangements have been found to suffer from the problem that wheel deformation modes cause unacceptable wear and/or stresses within the drive system and/or wheel. The present invention thus proposes a drive system for an aircraft landing gear, the drive system comprising: a pinion gear; a drive shaft arranged to rotate the pinion gear about a drive axis; a driven gear arranged to mesh with the pinion gear to be rotatable by the pinion gear, the driven gear being connectable to a wheel of the landing gear to be capable of rotating the wheel about a wheel axis; and a flexible interface. The flexible interface comprises a plurality of driven gear coupling members, each driven gear coupling member having a first connection portion attached to the driven gear, a second connection portion adapted to be attached to the wheel at an offset distance from the wheel axis, and a joint between the first connection portion and the second connection portion, the joint permitting relative movement between the first connection portion and the second connection portion.

First claim

1 . A drive system for an aircraft landing gear, the drive system comprising:
a pinion gear; a drive shaft arranged to rotate the pinion gear about a drive axis; a driven gear arranged to mesh with the pinion gear to be rotatable by the pinion gear, the driven gear being connectable to a wheel of the landing gear to be capable of rotating the wheel about a wheel axis; and a flexible interface comprising a plurality of driven gear coupling members, each driven gear coupling member having a first connection portion attached to the driven gear, a second connection portion adapted to be attached to the wheel at an offset distance from the wheel axis, and a joint between the first connection portion and the second connection portion, the joint permitting relative movement between the first connection portion and the second connection portion.

2 . A drive system according to claim 1 , wherein the joint comprises a spherical joint.

3 . A drive system according to claim 2 , wherein the spherical joint is arranged to be capable of translational movement relative to the first connection portion or second connection portion.

4 . A drive system according to claim 1 , wherein the joint permits relative movement within at least two degrees of freedom.

5 . A drive system according to claim 1 , wherein the joint permits translation of the first connection portion relative to the second connection portion along a first local axis substantially parallel to the wheel axis.

6 . A drive system according to claim 5 , wherein the joint comprises a kinematic cylindrical joint or a kinematic sliding joint to provide the translation along the first local axis.

7 . A drive system according to claim 1 , wherein the joint permits translation of the first connection portion relative to the second connection portion along a second local axis at an angle to the wheel axis.

8 . A drive system according to claim 7 , wherein the joint comprises a kinematic cylindrical joint or a kinematic spherical joint to provide the translation along the second local axis.

9 . A drive system according to claim 7 , wherein the second local axis is substantially radial to the wheel axis.

10 . A drive system according to claim 1 , wherein the joint permits: translation of the first connection portion relative to the second connection portion along a first local axis substantially parallel to the wheel axis, translation of the first connection portion relative to the second connection portion along a second local axis at an angle to the wheel axis, and relative rotation between the first and second local axes.

11 . A drive system according to claim 1 , wherein the driven gear is substantially ring-shaped and the plurality of driven gear coupling members are substantially evenly distributed about its circumference.

12 . A drive system according to claim 1 , wherein each driven gear coupling member comprises a resilient member arranged to bias the first connection portion towards the wheel axis.

13 . A drive system according to claim 1 , wherein the flexible interface comprises a pinion gear coupling member arranged to connect the pinion gear to the drive shaft to permit tilting of the pinion gear relative to the drive axis.

14 . A drive system according to claim 13 , wherein the pinion gear coupling member comprises a crowned spline joint between the drive shaft and the pinion gear.

15 . A drive system according to claim 13 , wherein the pinion gear coupling member comprises a constant velocity joint (CV joint) between the drive shaft and the pinion gear.

16 . A drive system according to claim 13 wherein the pinion gear coupling member is arranged to permit translation of the pinion gear along the drive axis.

17 . A drive system according to claim 1 , wherein the first connection portion of each driven gear coupling member comprises a bushing mounted on the driven gear and the joint comprises a cooperating cylindrical shaft connected to the second connection portion and arranged to slide within the bushing.

18 . A drive system according to claim 1 , wherein the second connection portion of each driven gear coupling member comprises a socket part and the joint comprises a ball part connected to the first connection portion and arranged to rotate and translate within the socket part.

19 . A drive system according to claim 1 , wherein the flexible interface comprises one or more failsafe catches, each failsafe catch being adapted for attachment to the wheel and arranged to retain the driven gear in the event of a failure of one or more of the driven gear coupling members.

20 . A drive system according to claim 19 , wherein the one or more failsafe catches are attached to the second portion of one or more of the driven gear coupling members.

21 . A drive system according to claim 1 , wherein one of the pinion gear and the driven gear comprises a sprocket and the other of the pinion gear and the driven gear comprises a series of rollers arranged to form a ring, each roller being rotatable about a roller axis at a fixed distance from an axis of rotation of the pinion gear or driven gear, respectively.

22 . A drive system according to claim 21 , wherein each of the series of rollers is rotatable about a pin, the pins each being fixed at at least one end to an annular support member.

23 . (canceled)

24 . (canceled)

Assignees

• Airbus Operations Ltd

Inventors

• Didey Arnaud

Classifications

• F16H1/006

  the driving and driven axes being designed to assume variable positions relative to one another during operation · CPC title

• B64C25/405 Primary

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

• F16H1/26

  Special means compensating for misalignment of axes · CPC title

• F16D3/00

  Yielding couplings, i.e. with means permitting movement between the connected parts during the drive (couplings disconnectable simply by axial movement F16D1/10; slip couplings F16D7/00) · CPC title

• F16H1/06

  with parallel axes · CPC title