Inboard bearing assemblies having independent shoes

Patent metadata

Field	Value
Publication number	US-10486807-B2
Application number	US-201815990623-A
Country	US
Kind code	B2
Filing date	May 26, 2018
Priority date	Jul 13, 2017
Publication date	Nov 26, 2019
Grant date	Nov 26, 2019

Abstract

A proprotor system for a tiltrotor aircraft having a helicopter flight mode and an airplane flight mode includes a yoke having a plurality of blade arms each having an inboard pocket with a load transfer surface. Each of a plurality of bearing assemblies is disposed at least partially within one of the inboard pockets. Each of a plurality of inboard beams is disposed at least partially between a centrifugal force bearing and a shear bearing of each bearing assembly and has a proprotor blade coupled thereto. Each of a plurality of independent shoes is coupled between one of the centrifugal force bearings and the yoke. Each shoe has a load transfer surface that has a contact relationship with the load transfer surface of the respective inboard pocket forming a centrifugal force load path therebetween.

First claim

What is claimed is:

1. A proprotor system for a tiltrotor aircraft having a helicopter flight mode and an airplane flight mode, the proprotor system comprising:
a yoke having a plurality of blade arms including a first blade arm having an inboard pocket with a load transfer surface;
a bearing assembly disposed at least partially within the inboard pocket, the bearing assembly including a centrifugal force bearing having an outboard mating surface and a shear bearing;
an inboard beam disposed at least partially between the centrifugal force bearing and the shear bearing;
a proprotor blade coupled to the inboard beam; and
an independent shoe coupled between the centrifugal force bearing and the yoke, the shoe having an inboard mating surface that contacts the outboard mating surface of the centrifugal force bearing forming an anti-rotation coupling therebetween, the shoe having a load transfer surface that has a contact relationship with the load transfer surface of the inboard pocket forming a centrifugal force load path therebetween.

2. The proprotor system as recited in claim 1 wherein the load transfer surfaces of the shoe and the inboard pocket have matching profiles.

3. The proprotor system as recited in claim 1 wherein the load transfer surfaces of the shoe and the inboard pocket have matching arcuate profiles.

4. The proprotor system as recited in claim 1 wherein the load transfer surfaces of the shoe and the inboard pocket have matching circular arc profiles.

5. The proprotor system as recited in claim 1 wherein the load transfer surfaces of the shoe and the inboard pocket have matching elliptical arc profiles.

6. The proprotor system as recited in claim 1 wherein the shoe has a bonded relationship with the yoke.

7. The proprotor system as recited in claim 1 wherein the shoe has a clamped relationship with the yoke outboard of the inboard pocket.

8. The proprotor system as recited in claim 7 wherein the shoe further comprises first and second clamp plates each having at least one shoe bolt opening, wherein the first blade arm defines at least one shoe bolt opening outboard of the inboard pocket and further comprising at least one shoe bolt passing through aligned shoe bolt openings of the clamp plates and the first blade arm to clamp the shoe to the yoke.

9. The proprotor system as recited in claim 1 wherein the shoe has a bonded and clamped relationship with the yoke.

10. The proprotor system as recited in claim 1 wherein the inboard mating surface of the shoe and the outboard mating surface of the centrifugal force bearing further comprise generally planar mating surfaces.

11. The proprotor system as recited in claim 1 wherein the inboard mating surface of the shoe and the outboard mating surface of the centrifugal force bearing further comprise generally conical mating surfaces.

12. The proprotor system as recited in claim 1 wherein the inboard mating surface of the shoe and the outboard mating surface of the centrifugal force bearing further comprise generally planar mating surface sections and generally conical mating surface sections.

13. The proprotor system as recited in claim 1 wherein at least a portion of the mating surfaces of the shoe and the centrifugal force bearing have a spaced apart relationship.

14. The proprotor system as recited in claim 1 wherein the anti-rotation coupling further comprises a radially extending non-cylindrical feature.

15. The proprotor system as recited in claim 1 wherein the anti-rotation coupling further comprises a radially extending multisided geometric prism feature.

16. The proprotor system as recited in claim 1 wherein the anti-rotation coupling further comprises a radially extending four-sided geometric prism feature.

17. The proprotor system as recited in claim 1 wherein the anti-rotation coupling further comprises a plurality of pins extending between the shoe and the centrifugal force bearing.

18. The proprotor system as recited in claim 1 wherein the anti-rotation coupling further comprises a plurality of threaded pins extending between the shoe and the centrifugal force bearing.

19. A tiltrotor aircraft having a helicopter flight mode and an airplane flight mode, the tiltrotor aircraft comprising:
a fuselage;
a wing extending from the fuselage;
first and second pylon assemblies coupled to the wing outboard of the fuselage; and
first and second proprotor systems operably associated respectively with the first and second pylon assemblies, each proprotor system including:
a yoke having a plurality of blade arms including a first blade arm having an inboard pocket with a load transfer surface;
a bearing assembly disposed at least partially within the inboard pocket, the bearing assembly including a centrifugal force bearing having an outboard mating surface and a shear bearing;
an inboard beam disposed at least partially between the centrifugal force bearing and the shear bearing;
a proprotor blade coupled to the inboard beam; and
an independent shoe coupled between the centrifugal force bearing and the yoke, the shoe having an inboard mating surface that contacts the outboard mating surface of the centrifugal force bearing forming an anti-rotation coupling therebetween, the shoe having a load transfer surface that has a contact relationship with the load transfer surface of the inboard pocket forming a centrifugal force load path therebetween.

Assignees

• Bell Helicopter Textron Inc
• Bell Textron Inc

Inventors

• Dearman Michael Dean
• Kizhakkepat Amarjit Olenchery
• Baldwin Tyler Wayne
• Burnett Michael Christopher

Classifications

• F16D3/76

  shaped as an elastic ring centered on the axis, surrounding a portion of one coupling part and surrounded by a sleeve of the other coupling part · CPC title

• F16D3/50

  with the coupling parts connected by one or more intermediate members (F16D3/16 takes precedence) · CPC title

• B64C11/06

  for variable-pitch blades · CPC title

• B64C27/35

  having elastomeric joints · CPC title

• F16D3/33

  with ball or roller bearings · CPC title