Constant Velocity Joint with Spring Rate Control Mechanism

• US 20140248150A1
• Filed: 04/22/2014
• Published: 09/04/2014
• Est. Priority Date: 11/09/2012
• Status: Active Grant

• Current Assignee: Bell Helicopter Textron Incorporated (Textron Inc)
• Original Assignee: Bell Helicopter Textron Incorporated (Textron Inc)
• Inventors: Sutton, Drew, Stamps, Frank B., Foskey, Christopher
• Granted Patent: US 9,878,783 B2
• Time in Patent Office: Days
• US Class Current: 416/1
• CPC Class Codes: B64C 27/32 Rotors
• CPC Class Codes: B64C 27/41 with flapping hinge or universal joint, common to the blades
• CPC Class Codes: F16D 3/28 in which the interconnecting pivots include elastic members
• CPC Class Codes: F16D 3/30 in which the coupling is specially adapted to constant velocity-ratio
• CPC Class Codes: F16D 3/33 with ball or roller bearings

Abstract

According to one embodiment, a constant velocity (CV) joint includes a first yoke, a second yoke, and three bearings. The first yoke is configured to be rotatably coupled to an input device about a first axis and configured to receive the input device through a first opening. The second yoke is rotatably coupled to the first yoke about a second axis and rotatably coupled to an output device about a third axis. The first bearing is disposed about the first axis adjacent to the first yoke, the second bearing is disposed about the second axis adjacent to the first yoke or the second yoke, and the third bearing disposed about the third axis adjacent to the second yoke. The first and third bearings torsionally constrain movement the first yoke and the second yoke so as to achieve a substantially CV characteristic between the input device and the output device.

Claims

1. A rotorcraft, comprising:

a body;

a power train coupled to the body and comprising a power source and a drive shaft coupled to the power source;

a hub;

a rotor blade coupled to the hub; and

a constant velocity (CV) joint coupled between the drive shaft and the hub, the CV joint comprising;

a first yoke rotatably coupled to the drive shaft about a first axis and configured to receive the drive shaft through a first opening;

a first bearing disposed about the first axis adjacent to the first yoke;

a second yoke rotatably coupled to the first yoke about a second axis and rotatably coupled to the hub about a third axis; and

a second bearing disposed about the second axis adjacent to the first yoke or the second yoke; and

a third bearing disposed about the third axis adjacent to the second yoke, wherein the first and third bearings torsionally constrain movement the first yoke and the second yoke so as to achieve a substantially CV characteristic between the drive shaft and the hub.

2. The rotorcraft of claim 1, wherein at least one of the first bearing, the second bearing, or the third bearing comprise an elastomeric material.

3. The rotorcraft of claim 1, wherein the second yoke is disposed about the first yoke.

4. The rotorcraft of claim 1, wherein the hub is disposed about the drive shaft.

5. The rotorcraft of claim 1, wherein the first axis is substantially normal to an axis of rotation of the drive shaft.

6. The rotorcraft of claim 1, wherein the third axis is substantially normal to an axis of rotation of the hub.

7. The rotorcraft of claim 1, wherein:

the hub is tilted at a first angle relative to the drive shaft; and

the first and third bearings are adapted to position the first and second yokes such that the second axis is tilted at a second angle relative drive shaft which is smaller in magnitude than the first angle.

8. The rotorcraft of claim 1, wherein the first and third bearings are adapted to position the first and second yokes such that the second axis substantially resides on a bisector of the angle.

9. The rotorcraft of claim 8, wherein the second bearing is positioned to travel along an arc representing a range of bisection angles.

10. The rotorcraft of claim 1, wherein second bearing is disposed about the second axis adjacent to the first yoke and the second yoke.

12. The rotorcraft of claim 1, wherein the first and third bearings are operable to torsionally constrain movement the first yoke and the second yoke when the first and third axes are substantially collinear.

13. The rotorcraft of claim 12, wherein the first and third bearings are operable to position the first and second yokes such that the second axis substantially resides on a bisector of an angle between the drive shaft and the hub when the first and third axes are substantially collinear.

17. The CV joint of claim 1, wherein the second yoke is disposed about the first yoke.

18. The CV joint of claim 1, wherein:

the hub is tilted at a first angle relative to the drive shaft; and

the first and third bearings are adapted to position the first and second yokes such that the second axis is tilted at a second angle relative drive shaft which is smaller in magnitude than the first angle.

19. The CV joint of claim 1, wherein the first and third bearings are adapted to position the first and second yokes such that the second axis substantially resides on a bisector of the angle.

20. The CV joint of claim 19, wherein the second bearing is positioned to travel along an arc representing a range of bisection angles.

14. A method of achieving a substantially constant velocity (CV) characteristic between an input device and an output device, comprising:

receiving the input device through a first opening in a first yoke, the first yoke rotatably coupled to the input device about a first axis and rotatably coupled to a second yoke about a second axis, the second yoke rotatably coupled to the output device about a third axis; and

constraining rotation of the first yoke about the first axis and rotation of the second yoke about the third axis so as to achieve a substantially CV characteristic between the drive shaft and the hub.

15. The method of claim 14, wherein constraining rotation of the first yoke and the second yoke comprises constraining an orientation of the second axis.

16. A constant velocity (CV) joint comprising:

a first yoke configured to be rotatably coupled to an input device about a first axis and configured to receive the input device through a first opening;

a first bearing disposed about the first axis adjacent to the first yoke;

a second yoke rotatably coupled to the first yoke about a second axis and rotatably coupled to an output device about a third axis; and

a second bearing disposed about the second axis adjacent to the first yoke or the second yoke; and

a third bearing disposed about the third axis adjacent to the second yoke, wherein the first and third bearings torsionally constrain movement the first yoke and the second yoke so as to achieve a substantially CV characteristic between the input device and the output device.