Compact rotorcraft dual-element spherical elastomeric centrifugal-force bearing assembly

1. A rotary system for a rotary aircraft, comprising:

a retention member, having:

an upper spoke arm; and

a lower spoke arm;

a flexible yoke, having:

an opening forming a bridge;

a blade grip for attaching a rotor blade to the flexible yoke, the grip having:

a base;

a first plate and a second plate extending from the base; and

a grip support member attached to the base and extending in a direction opposite to the first plate and the second plate;

a first bearing assembly for attaching the blade grip support to the retention member; and

a non-symmetrical second bearing assembly for attaching the base of the blade grip to the bridge of the flexible yoke;

the second bearing assembly comprising:

a bearing element disposed between a first elastomeric material and a second elastomeric material, the bearing element having:

a first surface forming a spherical contouring facing outboard; and

a second surface forming a conical contouring facing inboard;

wherein the first elastomeric material takes the form of and bonds to the first surface; and

wherein the second elastomeric material takes the form of and bonds to the second surface;

wherein the flexible yoke, first bearing assembly, and second bearing assembly react rotor blade forces exerted on the retention member during flight.

2. The rotary system of claim 1 , wherein only the flexible yoke, first bearing assembly, and second bearing assembly attach the rotor blade to the retention member.

3. The rotary system of claim 1 , wherein the first bearing assembly is a shear bearing.

4. The rotary system of claim 1 , wherein the first bearing assembly is attached to the upper spoke arm and the lower spoke arm of the retention member.

5. The rotary system of claim 1 , wherein the first bearing assembly is composed of elastomeric material.

6. The rotary system of claim 1 , wherein the first bearing assembly extends through the opening of the flexible yoke.

7. The rotary system of claim 1 , wherein the base of the grip extends through the opening of the flexible yoke.

8. The rotary system of claim 1 , the bearing assembly further comprising:

a bearing housing bonded to the first elastomeric material; and

a support member bonded to the second elastomeric material.

9. A rotary system for a rotary aircraft, comprising:

a retention member;

a flexible yoke, having:

an opening forming a bridge;

a first bearing assembly extending through the opening of the yoke and configured to secure a rotor blade to the retention member; and

a second non-symmetrical bearing assembly extending through the opening of the flexible yoke and configured to secure the rotor blade to the bridge;

the second bearing assembly comprising:

a bearing element disposed between a first elastomeric material and a second elastomeric material, the bearing element having:

a first surface forming a spherical contouring facing outboard; and

a second surface forming a conical contouring facing inboard;

wherein the first elastomeric material takes the form of and bonds to the first surface; and

wherein the second elastomeric material takes the form of and bonds to the second surface;

wherein the flexible yoke, first bearing assembly, and second bearing assembly react rotor blade forces exerted on the retention member during flight.

10. The rotary system of claim 9 , further comprising:

a blade grip rigidly attached to the blade and elastically attached to the first bearing assembly and the second bearing assembly.

11. The rotary system of claim 10 , the blade grip comprising:

a base extending through the opening of the flexible yoke;

a first plate and a second plate extending from the base; and

a grip support member attached to the base and extending in a direction opposite to the first plate and the second plate;

wherein the first plate and the second plate rigidly attach to a root portion of the blade.

12. The rotary system of claim 11 , wherein the second bearing is disposed between the first plate and the second plate.

13. The rotary system of claim 12 , wherein the second bearing is attached to the base of the blade grip.

14. The rotary system of claim 10 , wherein only the flexible yoke, first bearing assembly, and second bearing assembly attach the grip to the retention member.

15. The rotary system of claim 9 , wherein the first bearing assembly is a shear bearing.

16. A rotary system for a rotary aircraft, comprising:

a retention member;

a flexible yoke, having:

an opening forming a bridge;

a first bearing assembly disposed within the opening of the yoke and configured to secure a rotor blade to the retention member; and

a second non-symmetrical bearing assembly disposed within the opening of the flexible yoke and configured to secure the rotor blade to the bridge of the flexible yoke, the second bearing element, having:

a bearing element disposed between a first elastomeric material and a second elastomeric material, the bearing element having:

a first surface forming a spherical contouring; and

a second surface forming a conical contouring;

wherein the first elastomeric material takes the form of and bonds to the first surface; and

wherein the second elastomeric material takes the form of and bonds to the second surface.

17. The rotary system of claim 16 , further comprising:

a blade grip rigidly attached to the blade and elastically attached to the first bearing assembly and the second bearing assembly, the blade grip comprising:

a base disposed within the opening of the flexible yoke;

a first plate and a second plate extending from the base; and

a grip support member attached to the base and extending in a direction opposite to the first plate and the second plate;

wherein the first plate and the second plate rigidly attach to a root portion of the blade.

18. The rotary system of claim 17 , wherein the second bearing is disposed between the first plate and the second plate; and

wherein the second bearing is attached to the base of the blade grip.