Friction damper with centering flexure

Patent metadata

Field	Value
Publication number	US-2016264237-A1
Application number	US-201514657478-A
Country	US
Kind code	A1
Filing date	Mar 13, 2015
Priority date	Mar 13, 2015
Publication date	Sep 15, 2016
Grant date	—

Abstract

A tail rotor drive system (TRDS) has a shaft, a housing extending around the shaft, a mount coupled to the housing via a friction assembly and a flexure, and a bearing assembly disposed between the housing and the shaft.

First claim

What is claimed is:

1 . A tail rotor drive system (TRDS), comprising:
a shaft; a housing extending around the shaft; a mount coupled to the housing via a friction assembly and a flexure; and a bearing assembly disposed between the housing and the shaft.

2 . The TRDS of claim 1 , wherein the shaft comprises a supercritical shaft configured for operation above a critical speed.

3 . The TRDS of claim 1 , wherein each friction assembly comprises a biasing spring and a friction ring.

4 . The TRDS of claim 1 , wherein each flexure comprises:
titanium.

5 . The TRDS of claim 1 , wherein each flexure comprises:
a U-shape.

6 . The TRDS of claim 1 , wherein each flexure comprises:
a plate-like structure.

7 . The TRDS of claim 1 , wherein each flexure comprises:
a first leg; a second leg; and a curved portion connecting the first leg to the second leg.

8 . The TRDS of claim 7 , wherein the first leg is shorter than the second leg.

9 . The TRDS of claim 8 , wherein the first leg is attached to the mount.

10 . The TRDS of claim 8 , wherein the second leg is attached to the housing.

11 . The TRDS of claim 1 , wherein the bearing assembly is configured to constantly react to a load of the shaft.

12 . The TRDS of claim 11 , wherein the bearing assembly comprises:
roller elements.

13 . The TRDS of claim 11 , wherein the bearing assembly comprises:
a permanent magnet.

14 . The TRDS of claim 1 , wherein the flexures are configured to bias the shaft to a radially centered position.

15 . The TRDS of claim 1 , wherein the friction assemblies are configured to accommodate radial movement of the shaft and associated housing.

16 . A helicopter, comprising:
a tail rotor drive system (TRDS) comprising:
a shaft;
a housing extending around the shaft;
a mount coupled to the housing via a friction assembly and a flexure; and
a bearing assembly disposed between the housing and the shaft.

17 . The helicopter of claim 16 , wherein the shaft comprises:
a supercritical shaft configured for operation above a critical speed.

18 . The helicopter of claim 16 , wherein the flexures each comprise:
a U-shape and wherein the bearing assembly is configured to constantly react to a load of the shaft.

19 . A friction damper, comprising:
a housing configured for extending around a shaft; a mount coupled to the housing via a friction assembly and a flexure; and a bearing assembly disposed between the housing and the shaft.

20 . The friction damper of claim 19 , wherein the flexure comprises:
a U-shaped plate-like structure comprising:
a first leg;
a second leg; and
a curved portion connecting the first leg to the second leg;
wherein the first leg is shorter than the second leg; wherein the first leg is attached to the mount; wherein the second leg is attached to the housing; and wherein the bearing assembly is configured to constantly react to a load of the shaft.

Assignees

• Bell Helicopter Textron Inc

Inventors

• Spears Steven Kirk
• Chavez Andrea Cheri
• Ekstrom Brad Jeffrey

Classifications

• B64C27/14 Primary

  Direct drive between power plant and rotor hub · CPC title

• F16C19/00

  Bearings with rolling contact, for exclusively rotary movement (adjustable bearings F16C23/00, F16C25/00 {; electrically insulating bearings H02K5/173}) · CPC title

• F16C27/00

  Elastic or yielding bearings or bearing supports, for exclusively rotary movement (shock-damping bearings for watches or clocks G04B31/02) · CPC title

• F16C2326/43

  Aeroplanes; Helicopters · CPC title

• F16C32/0425

  for radial load mainly · CPC title