Articulated main rotor hub with inwardly CF bearing and 3% flapping hinge offset

Patent metadata

Field	Value
Publication number	US-9764831-B2
Application number	US-201414202617-A
Country	US
Kind code	B2
Filing date	Mar 10, 2014
Priority date	Mar 10, 2014
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

A rotary system including a grip having an opening forming a first bridge for receiving a centrifugal force bearing that faces inwardly towards the rotor mast. A rotor blade couples to the grip and a pitch horn positioned outside the opening pitches the rotor blade during flight. A bearing assembly attaches the first bridge to the yoke and controls blade forces exerted against the hub assembly during flight.

First claim

What is claimed is:

1. A rotary system for a rotary aircraft, comprising:
a rotor mast;
a swashplate rotatably carried by the rotor mast; and
a hub assembly for securing a rotor blade to the rotor mast, the hub assembly having:
a yoke rigidly attached to the rotor mast, the yoke having:
an upper plate; and
a lower plate;

a blade grip for securing the rotor blade to the yoke, the grip having:
a thickness; and
an opening extending through the thickness, the opening forming a bridge;
wherein the blade grip is operably associated with the swashplate for providing pitching movement of the blade during flight;

a damper pivotally attached to the blade grip and the yoke; and
a bearing assembly having;
a spherical centrifugal bearing having;
a conical profile bounded substantially by a pair of coaxial spherical surfaces; and
a focal center positioned inwardly towards the rotor mast;

wherein the bearing assembly is configured to attach the blade grip to the yoke; and

wherein the bearing assembly controls blade forces exerted against the hub assembly during flight.

2. The rotary system of claim 1 , wherein the spherical centrifugal bearing is composed of elastomeric material.

3. The rotary system of claim 1 , wherein the focal center of the spherical centrifugal bearing is located at a first distance from the rotor mast; and
wherein a center of the pivotal attachment between the damper and the yoke is located the first distance from the rotor mast.

4. The rotary system of claim 1 , wherein an apex of the spherical centrifugal bearing is positioned towards the rotor mast.

5. The rotary system of claim 1 , wherein the spherical centrifugal bearing is asymmetrical shaped.

6. The rotary system of claim 2 , further comprising a coning stop.

7. The rotary system of claim 6 , the coning stop having:
a weighed first member; and
a second member;
wherein the blade grip rests on the second member during periods of low centrifugal force exerted on the rotary system.

8. The rotary system of claim 1 , wherein an apex of the spherical centrifugal bearing faces the bridge.

9. A rotary system for a rotary aircraft, comprising:
a yoke;
a grip having an opening forming a bridge and rigidly attached to a rotor blade; and
a bearing assembly having a spherical centrifugal bearing having a conical profile bounded substantially by a pair of coaxial spherical surfaces;
wherein a diameter of the spherical centrifugal bearing is the smallest closest to an axis of rotation of the yoke;
wherein the bearing assembly is operably associated with the grip, the bearing assembly being configured to attach the grip to the yoke;
wherein the bearing assembly controls blade forces exerted against a hub assembly during flight; and
wherein a focal center of the spherical centrifugal bearing is positioned towards a center of the yoke.

10. The rotary system of claim 9 , the yoke comprising:
an upper plate; and
a lower plate.

11. The rotary system of claim 10 , further comprising:
a coning stop.

12. The rotary system of claim 9 , wherein the spherical centrifugal bearing is located within the opening of the grip.

13. The rotary system of claim 9 , further comprising:
a damper pivotally connecting the yoke to the grip;
wherein a focal center of bearing assembly is located at a blade station equal to a blade station of a center of the pivotal attachment between the damper and the yoke.

Assignees

• Jarrett Chad Lewis
• Stamps Frank Bradley
• Shimek Glenn
• Bell Helicopter Textron Inc

Inventors

• Jarrett Chad Lewis
• Stamps Frank Bradley
• Shimek Glenn

Classifications

• B64C27/35

  having elastomeric joints · CPC title

• B64C27/605 Primary

  including swash plate, spider or cam mechanisms · CPC title