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BR-102019026293-B1 - AIRCRAFT SYSTEM AND METHOD FOR TRANSMITTING ENERGY FROM A FIRST COMPONENT TO A SECOND COMPONENT

BR102019026293B1BR 102019026293 B1BR102019026293 B1BR 102019026293B1BR-102019026293-B1

Abstract

INVERTED COMPOUND HARMONIC DRIVE, AIRCRAFT SYSTEM, AND METHOD FOR TRANSMITTING ENERGY FROM A FIRST COMPONENT TO A SECOND COMPONENT An inverted compound harmonic drive including: a wave generator configured to receive rotational input; a flexible spline radially arranged within the wave generator that receives energy due to the rotation of the wave generator, the flexible spline including a plurality of inward-facing splines that include a central axial spline, a first end axial spline being adjacent to and ahead of the central axial spline and a second axial spline adjacent to and behind the central axial spline; an output gear meshing with the central axial spline; a first ground gear adjacent to and ahead of the output gear meshing with the first end axial spline; and a second ground gear adjacent to and behind the output gear meshing with the second end axial spline.

Inventors

  • DERICK S. BALSIGER
  • Keith Bloxham

Assignees

  • HAMILTON SUNDSTRAND CORPORATION

Dates

Publication Date
20260317
Application Date
20191211
Priority Date
20190418

Claims (11)

  1. 1. Aircraft system comprising: an inverted compound harmonic drive (100) comprising: a wave generator (110) configured to receive rotational input; a flexible spline (120) radially disposed within the wave generator (110) receiving energy due to the rotation of the wave generator (110), the flexible spline (120) including a plurality of inward-facing splines (130) including an axial center spline (130a), a first axial end spline (130b) being adjacent to and ahead of the axial center spline (130a) and a second axial spline (130c) adjacent to and behind the axial center spline (130a); an output gear (140) meshing with the axial center spline (130a); a first ground gear (150) adjacent to and ahead of the output gear (140) meshing with the first axial end spline (130b); and a second ground gear (160) adjacent to a rear part of the output gear (140) that meshes with the second axial end spline (130c); characterized in that: the first axial end spline (130b) and the first ground gear (150) have a first gear ratio; the second axial end spline (130c) and the second ground gear (160) have a second gear ratio that is equal to the first gear ratio; and the first central axial spline (130a) and the output gear (140) have a third gear ratio different from the first and second gear ratios; wherein: the first ground gear (150) includes a first ground shaft (170) that extends in a forward direction and is connected to the aircraft ground structure; the second ground gear (160) includes a second ground shaft (172) that extends in a rear direction and is connected to the aircraft ground structure; the output gear (140) includes an output shaft (180), the output shaft (180) including one or more of: a first shaft portion (180a) extending in the forward direction with a first passage (180c) through it, the first passage (180c) being splined; and a second shaft portion (180b) extending in the rear direction with a second passage (180d) through it, the second passage (180d) being continuous with the first passage (180c), the second passage (180d) being splined; wherein: the wave generator (110) receives a rotation input from a first aircraft component (102); and wherein the output shaft (140) is configured to connect to a second aircraft component (104).
  2. 2. System according to claim 1, characterized in that: the first ground shaft (170) has a third passage (170a) through it with a third passage diameter; the second ground shaft (172) has a fourth passage (172a) through it with a fourth passage diameter; the first shaft portion (180a) of the output shaft extends through the third passage (170a); and the second shaft portion (180b) of the output shaft extends through the fourth passage (172a).
  3. 3. System according to claim 2, characterized in that the first ground axis (170) and the second ground axis (172) each include a plurality of mounting holes (190).
  4. 4. System according to claim 3, characterized in that it comprises: a first axial end bearing (200) disposed between the first ground shaft (170) and the wave generator (110); a second axial end bearing (210) disposed between the second ground shaft (172) and the wave generator (110); and a central axial bearing (220) disposed between the flexible spline (120) and the wave generator (110).
  5. 5. System according to claim 4, characterized in that: the first axial bearing (200) and the second axial bearing (210) are roller bearings, ball bearings or plain bearings; and the central axial bearing (220) is a roller bearing, a ball bearing or a plain bearing.
  6. 6. System according to claim 5, characterized in that: a first retaining ring (230) is disposed between the first axial end bearing (200) and the axial center bearing (220) and against the first axial end bearing (200); a first thrust washer (240) is disposed between the first axial end bearing (200) and the axial center bearing (220) and against the axial center bearing (220); a second retaining ring (245) is disposed between the second axial end bearing (210) and the axial center bearing (220) and against the second axial end bearing (210); and a second thrust washer (250) is disposed between the second axial end bearing (210) and the axial center bearing (220) and against the axial center bearing (220).
  7. 7. System according to claim 4, characterized in that: a first retaining ring (230) and a first thrust washer (240) are arranged between the first axial end bearing (200) and the axial center bearing (220), wherein the first retaining ring (230) is against the first axial end bearing (200) and the first thrust washer (240) is against the axial center bearing (220); and a second retaining ring (245) and a second thrust washer (250) are arranged between the second axial end bearing (210) and the axial center bearing (220), wherein the second retaining ring (245) is against the second axial end bearing (210) and the second thrust washer (250) is against the axial center bearing (220).
  8. 8. Method for transmitting energy from a first component (102) to a second component (104), in an aircraft system as defined in claim 1, characterized in that it comprises: coupling the inverted compound harmonic drive (100) to the first component (102), to the second component (104) and to the aircraft ground structure; transmitting energy from the first component (102) to the wave generator (110) of the inverted compound harmonic drive (100); transmitting energy from the wave generator (110) to the flexible groove (120) of the inverted compound harmonic drive (100); and transmit power from the flexible spline (120) to: the output gear (140) which meshes with the central axial spline (130a) of the flexible spline (120); the first ground gear (150) is adjacent to and ahead of the output gear (140) which meshes with the first axial end spline (130b) of the flexible spline (120); and the second ground gear (160) is adjacent to and ahead of the output gear (140) which meshes with the second axial end spline (130c) of the flexible spline (120); transmit power from the output gear (140) through the output shaft (180) to the second component (104).
  9. 9. Method according to claim 8, characterized in that it comprises coupling the output shaft (180) to the second component (104) with a spline on the output shaft.
  10. 10. Method according to claim 9, characterized in that it comprises: attaching a first ground shaft (170) to the first ground gear (150) extending in a forward direction from the first aircraft structure; and attaching a second ground shaft (172) to the second ground gear (160) extending in a rearward direction from the second aircraft structure.
  11. 11. Method according to claim 10, characterized in that it comprises: rotatably connecting the second component (104) to one of: the first output shaft portion (180a) of the output shaft (180) extending forward through the first ground gear (150); and the second output shaft portion (180b) of the output shaft (180) extending backward through the second ground gear (160).

Description

FUNDAMENTALS [001] The disclosure refers to reduction gears and, more specifically, to an aircraft system comprising an inverted compound harmonic drive. [002] An aircraft uses a flight control system to control one or more movable control surfaces. For example, an aircraft may include a plurality of movable control surfaces located along or near the wing's trailing edge, horizontal stabilizer, and vertical stabilizer. [003] A typical flight control surface is controlled by one or more actuators. [004] An example of an actuator that can be used in a flight control system (FCS) is an electromechanical actuator (EMA). Aircraft manufacturers may eventually replace all or part of the previous hydraulic systems that activate flight controls with lighter and simpler electrical systems. In such systems, instead of using hydraulics to generate power, electromechanical input can be provided to a compound harmonic drive that uses a gear reduction ratio to minimize system size. BRIEF DESCRIPTION [005] An aircraft system is disclosed comprising an inverted compound harmonic drive comprising: a wave generator configured to receive rotational input; a flexible spline radially disposed within the wave generator that receives energy due to the rotation of the wave generator, the flexible spline including a plurality of inwardly facing splines that include a central axial spline, a first end axial spline being adjacent to and ahead of the central axial spline and a second end axial spline adjacent to and behind the central axial spline; an output gear meshing with the central axial spline; a first ground gear adjacent to and ahead of the output gear meshing with the first end axial spline; and a second ground gear adjacent to and behind the output gear meshing with the second end axial spline. [006] In addition to one or more of the elements disclosed above, the first end axial spline and the first ground gear have a first gear ratio; the second end axial spline and the second ground gear have a second gear ratio that is equal to the first gear ratio; and the center axial spline and the output gear have a third gear ratio that differs from the ratios of the first and second gears. [007] In addition to one or more of the elements disclosed above or as an alternative, the first ground gear includes a first ground shaft extending in a forward direction; the second ground gear includes a second ground shaft extending in a backward direction; and the output gear includes an output shaft, the output shaft including one or more of: a first shaft portion extending in a forward direction with a first passage through it, the first passage being splined; and a second shaft portion extending in a backward direction with a second passage through it, the second passage being continuous with the first passage, the second passage being splined. [008] In addition to one or more of the elements disclosed above or as an alternative, the first ground shaft has a third passage through it with a third-pass diameter; the second ground shaft has a fourth passage through it with a fourth-pass diameter; the first portion of the output shaft extends through the third passage; and the second portion of the output shaft extends through the fourth passage. [009] In addition to one or more of the elements disclosed above or as an alternative, the first ground axis and the second ground axis each include a plurality of mounting holes. [0010] In addition to one or more of the elements disclosed above or as an alternative, the drive includes a first axial end bearing disposed between the first ground shaft and the wave generator; a second axial bearing disposed between the second ground shaft and the wave generator; and a central axial bearing disposed between the flexible spline and the wave generator. [0011] In addition to one or more of the elements disclosed above or as an alternative, the first axial bearing and the second axial bearing are ball bearings; and the central axial bearing is a roller bearing, a ball bearing or a plain bearing. [0012] In addition to one or more of the elements disclosed above or as an alternative, the drive includes a first retaining ring disposed between the first axial end bearing and the axial center bearing and against the first axial end bearing; a first thrust washer disposed between the first axial end bearing and the axial center bearing and against the axial center bearing; a second retaining ring between the second axial end bearing and the axial center bearing and against the second axial end bearing; and a second thrust washer between the second axial end bearing and the axial center bearing and against the axial center bearing. [0013] In addition to one or more of the elements disclosed above or as an alternative, the first ground shaft connects to the aircraft ground structure and the second ground shaft connects to the aircraft ground structure, and the output shaft is configured to connect to a second aircra