AIRCRAFT STABILIZER ACTUATOR

• US 20110048147A1
• Filed: 09/01/2010
• Published: 03/03/2011
• Est. Priority Date: 09/01/2009
• Status: Active Grant

• Current Assignee: Parker Intangibles LLC (Parker-Hannifin Corporation)
• Original Assignee: Parker-Hannifin Corporation
• Inventors: Keech, Nancy Kay, Polcuch, Eric A., Cyrot, Luc P.
• Granted Patent: US 8,960,031 B2
• Time in Patent Office: Days
• US Class Current: 74/89.26
• CPC Class Codes: B64C 13/341 having duplication or stand-by provisions
• CPC Class Codes: B64C 5/02 Tailplanes
• CPC Class Codes: F16H 25/205 comprising alternate power paths, e.g. for fail safe back-up
• CPC Class Codes: Y10T 74/18568 Reciprocating or oscillating to or from alternating rotary
• CPC Class Codes: Y10T 74/186 Alternate power path operable on failure of primary

Abstract

An actuator for actuating movement of a control surface relative to a structure can include a high-efficiency assembly and a low-efficiency assembly. The high-efficiency assembly can be connectable between a control surface and a structure for providing a first load transfer assembly and the assembly can have minimum backlash. The low-efficiency assembly is connectable between the control surface and the structure for providing a second load transfer assembly. The low-efficiency or irreversible assembly can be disposed in parallel relationship to the high-efficiency assembly and can have a higher backlash than the low-efficiency assembly. The low-efficiency assembly can be unloaded in normal operation. The actuator also can include a coupler for that can have a closed state in which both load transfer assemblies are synchronously driven by the drive mechanism, and an open state in which the drive mechanism is decoupled from the low-efficiency assembly and the low-efficiency assembly can inhibit movement of the control surface.

Claims

1. An actuator for actuating movement of a control surface relative to a structure, comprising:

a first load transfer assembly comprising a high-efficiency assembly, the first load transfer assembly connectable between a control surface and a structure for providing a first load path between the control surface and the structure;

a second load transfer assembly disposed in parallel relationship to first load path assembly and comprising a low-efficiency assembly, the second load transfer assembly connectable between the control surface and the structure for providing a second load path between the control surface and the structure;

a drive mechanism for driving the high-efficiency assembly and the low-efficiency assembly; and

a coupler having a closed state in which the drive mechanism is coupled to the high-efficiency assembly and the low-efficiency assembly such that the high-efficiency assembly and the low-efficiency assembly are synchronously driven, and an open state in which the drive mechanism is decoupled from the low-efficiency assembly so that low-efficiency assembly can inhibit movement of the control surface.

2. The actuator of claim 1, wherein the first load path and the second load path are concentric with one another.

3. The actuator of claim 1, wherein the first load path and the second load path are parallel and laterally offset from one another.

4. The actuator of claim 1, wherein the coupler includes a lock mechanism engageable to a housing of the actuator when the coupler is in the open state, whereby movement of the low-efficiency assembly is further inhibited when the lock mechanism is engaged to the housing.

5. The actuator of claim 4, further comprising a sensor for sensing a load in the second load path.

6. The actuator of claim 5, wherein the coupler is configured to move to the open state upon the detection of a load in the second load path.

7. The actuator of claim 1, wherein the low-efficiency assembly holds the control surface at a last commanded position by opening the coupler when a failure is detected in the high-efficiency assembly.

8. The actuator of claim 1, wherein the coupler is an electrically or hydraulically operated coupler biased to the closed state and releasable to the open state upon detection of a failure event.

9. The actuator of claim 1, wherein the high-efficiency assembly comprises a ball or roller screw and nut.

10. The actuator of claim 1, wherein the low-efficiency assembly comprises an inverted Acme screw and an externally threaded nut.

11. The actuator of claim 1, wherein the low-efficiency assembly is irreversible.

12. The actuator of claim 1, wherein the low-efficiency assembly comprises any combination of low-efficiency, irreversible screw, or a screw in with an irreversible mechanism including at least one of high friction thrust flanges and/or no-back devices.

13. The actuator of claim 1, wherein the first load transfer assembly includes a first connector for connection to the control surface and a second connector for connection to the structure;

and

wherein the second load transfer assembly includes first connector for connection to the control surface and a second connector for connection to the structure, and

wherein the high-efficiency assembly effects movement of the connecting members on the control surface relative to the connecting members on the structure.

14. The actuator of claim 1, wherein the low-efficiency assembly has a backlash that is greater than a backlash of the high-efficiency assembly, whereby load from the drive mechanism is carried primarily in the first load transfer assembly.

15. A method of using the actuator of claim 1, comprising:

driving the drive mechanism with the coupler in the closed state to synchronously drive the high-efficiency assembly and the low-efficiency assembly;

determining when a failure condition exists in the first load transfer assembly;

opening the coupler upon detection of a failure condition to thereby decouple the low-efficiency assembly from the drive mechanism, and

inhibiting movement of the control surface with the low-efficiency assembly.

16. The method of claim 15, wherein the determination of whether a failure condition exists includes sensing a load in the second load path.

17. The method of claim 15, further comprising engaging a locking mechanism to lock the low-efficiency assembly to the housing when the coupler is in the closed state.

18. A method for testing the actuator of claim 1, comprising:

driving the drive mechanism when the coupler is in the closed state to synchronously drive the high-efficiency assembly and the low-efficiency assembly; and

determining if the low-efficiency assembly inhibits movement of the high-efficiency assembly, whereby the inhibition of movement by the low-efficiency assembly with the coupler in the open state indicates integrity of the first load transfer assembly and the second load transfer assembly.

19. The method of claim 18, further comprising:

opening the coupler to thereby decouple the drive mechanism from the low-efficiency assembly;

driving the drive mechanism to load the first load transfer assembly, whereby the load is transferred from the first load transfer assembly to the second load transfer assembly through the control surface; and

determining whether a failure condition exists in the second load transfer assembly.

20. The method of claim 19, wherein determining whether a failure condition exists in the second load transfer assembly comprises:

sensing, with a sensor associated with the actuator that senses a load in the second load path, whether a load has been transferred to the load transfer assembly; and

determining that a failure condition exists when the sensor senses that no load has been transferred from the first load transfer assembly to the second load transfer assembly.

21. A method for measuring backlash in the actuator of claim 1, comprising:

decoupling the low-efficiency assembly from the drive mechanism by opening the coupler;

driving the drive mechanism in a first direction to drive the high-efficiency assembly in a corresponding first direction, whereby the low-efficiency assembly inhibits movement of the driven assembly in the first direction;

detecting a first stall position of the drive mechanism caused by the low-efficiency mechanism inhibiting movement of the driven assembly;

driving the drive mechanism in a second direction to drive the high-efficiency assembly in a corresponding second direction, whereby the low-efficiency assembly inhibits movement of the driven high-efficiency assembly in the second direction;

detecting a second stall position of the drive mechanism caused by the low-efficiency assembly inhibiting movement of the driven high-efficiency assembly;

determining the overall backlash of the actuator by comparing the first stall position and the second stall position.

22. The method of claim 21, wherein the drive mechanism is a motor, and the determination of the overall backlash of the actuator comprises measuring a number of revolutions of the motor between the first stall position and the second stall position.

23. The method of claim 22, further comprising driving the motor to a position between the first stall position and the second stall position prior to closing the coupler to engage the drive mechanism to the low-efficiency assembly at a mid-backlash position of the low-efficiency assembly backlash.