No-back/torque limiter device with torque sensing elements

Patent metadata

Field	Value
Publication number	US-10900528-B2
Application number	US-201816116974-A
Country	US
Kind code	B2
Filing date	Aug 30, 2018
Priority date	Aug 30, 2017
Publication date	Jan 26, 2021
Grant date	Jan 26, 2021

Abstract

A torque limiter and no-back assembly comprises an input shaft, an output shaft, a torque limiter provided between the input shaft and the output shaft, the torque limiter comprising a torque sensing element; and a no-back device arranged to brake the output shaft when the torque sensing element senses levels of torque above a threshold level between the input shaft and the output shaft, characterised in that the torque sensing element comprises a torsion spring having ends which are coupled to the input shaft and the output shaft for rotation therewith.

First claim

The invention claimed is:

1. A torque limiter and no-back assembly comprising:
an input shaft;
an output shaft;
a torque limiter provided between the input shaft and the output shaft, the torque limiter comprising a torque sensing element; and
a no-back device arranged to brake the output shaft when the torque sensing element senses levels of torque above a threshold level between the input shaft and the output shaft;
wherein the torque sensing element comprises a torsion spring having ends which are coupled to the input shaft and the output shaft for rotation therewith, and
wherein the torque sensing element is also arranged to transmit torque between the input shaft and the output shaft through a displaceable torque coupling allowing axial movement of one end of the torque sensing element.

2. The torque limiter and no-back assembly as claimed in claim 1 , wherein the torque sensing element senses torque by undergoing torsion, the torsion in the torque sensing element allowing a predetermined amount of relative rotation between the input shaft and the output shaft prior to activation of the no-back device to brake the output shaft.

3. The torque limiter and no-back assembly as claimed in claim 1 , wherein the displaceable torque coupling is positioned between the torque sensing element and the output shaft.

4. The torque limiter and no-back assembly as claimed in claim 1 , wherein the torque limiter comprises at least one support at one or each end for coupling rotation from the input shaft and the output shaft into a respective end of the torque sensing element.

5. The torque limiter and no-back assembly as claimed in claim 1 , wherein the no-back device is provided between the input shaft and the output shaft in parallel with the torque limiter, the no-back device being arranged to activate a brake to ground torque to a housing if torque has exceeded the threshold level.

6. A torque limiter and no-back assembly comprising:
an input shaft;
an output shaft;
a torque limiter provided between the input shaft and the output shaft, the torque limiter comprising a torque sensing element; and
a no-back device arranged to brake the output shaft when the torque sensing element senses levels of torque above a threshold level between the input shaft and the output shaft;
wherein the torque sensing element comprises a torsion spring having ends which are coupled to the input shaft and the output shaft for rotation therewith;

wherein the no-back device comprises a no-back spring arranged within a housing, the no-back spring being a torsion spring which expands radially under torque to engage a seat provided by the housing.

7. The torque limiter and no-back assembly as claimed in claim 6 , wherein the no-back spring has the same winding direction as the torque sensing element and wherein the torque sensing element extends within the no-back spring.

8. The torque limiter and no-back assembly as claimed in claim 6 , wherein the no-back spring comprises ends, one of which is allowed to rotate relative to one of the input shaft or the output shaft when torque is not being transmitted by the no-back spring.

9. The torque limiter and no-back assembly as claimed in claim 8 , wherein a second end of the no-back spring is fixed to the output shaft by mechanical engagement with a groove.

10. The torque limiter and no-back assembly as claimed in claim 7 , wherein the torque limiter further comprises input surfaces at one or both of the input shaft and/or the output shaft to couple torque into the no-back device, wherein one or more of the input surfaces is rotationally spaced from an adjacent end of the no-back spring when torque is absent from the assembly.

11. The torque limiter and no-back assembly as claimed in claim 8 , wherein the torque input surfaces comprise teeth which engage the ends of the no-back spring, and wherein both ends of the no-back spring are arranged to be in engagement with respective adjacent teeth once a predetermined amount of relative rotation has occurred between the input shaft and the output shaft.

12. The torque limiter and no-back assembly as claimed in claim 6 , wherein the torque sensing element is stiffer under torsion than the no-back spring, and preferably wherein the torque sensing element comprises a smaller number of coils than the no-back spring, or comprises a torsion spring having thicker coils, and/or is formed from a material having a greater modulus of elasticity than the no-back spring.

13. The torque limiter and no-back assembly as claimed in claim 4 , wherein the assembly comprises a second torque sensing element arranged on an opposite end of the output shaft to sense torque in an opposite direction of rotation to the other, first torque sensing element.

14. The torque limiter and no-back assembly as claimed in claim 13 , wherein the assembly comprises a second no-back device which is arranged to brake the output shaft when the second torque sensing element senses levels of torque above a threshold level between the input shaft and the output shaft in the opposite direction.

15. The torque limiter and no-back assembly as claimed in claim 14 , wherein the second no-back device comprises a second no-back spring arranged within a second housing, the second no-back spring being a torsion spring which expands radially under torque to engage a seat provided by the second housing.

16. The torque limiter and no-back assembly as claimed in claim 15 , the second no-back spring has the same winding direction as the second torque sensing element, and/or wherein the second torque sensing element extends within the second no-back spring.

17. The torque limiter and no back assembly as claimed in claim 14 , wherein the output shaft comprises a worm gear for engagement with an actuator, the worm gear being located between the two torque sensing elements and between the two no-back springs.

18. An actuator for a flight control surface comprising the torque limiter and no-back assembly of claim 1 .

19. A method of sensing torque in a torque limiter and no-back assembly, the assembly comprising an input shaft, an output shaft, a torque limiter provided between the input shaft and the output shaft, the torque limiter comprising a torque sensing element, and a no-back device arranged to brake the output shaft when the torque sensing element senses levels of torque above a threshold level between the input shaft and the output shaft, wherein the method uses a torsion spring for the torque sensing element which has ends coupled to the input shaft and the output shaft for rotation therewith, such that torque is sensed through torsion of the torque sensing element, wherein the torque sensing element is also arranged to transmit torque between the input shaft and the output shaft through a displaceable torque coupling allowing axial movement of one end of the torque sensing element.

20. The method of sensing and transmitting torque as claimed in claim 19 , wherein the assembly comprises a second torque sensing element in the form of a second torsion spring arranged on an opposite end of the output shaft, the second torsion spring being arranged to sense torque in an opposite direction to the first torque sensing element.

Assignees

• Microtecnica Srl

Inventors

• Gianfranceschi Marco

Classifications

• F16D3/10

  Couplings with means for varying the angular relationship of two coaxial shafts during motion · CPC title

• B64C13/28 Primary

  mechanical · CPC title

• F16D3/72

  with axially-spaced attachments to the coupling parts (F16D3/56 takes precedence) · CPC title

• F16D55/38

  mechanically actuated · CPC title

• Y02T50/40

  Weight reduction · CPC title