Ballscrew assembly with detection feature

• US 8,281,678 B2
• Filed: 12/30/2008
• Issued: 10/09/2012
• Est. Priority Date: 12/30/2008
• Status: Active Grant

• Current Assignee: Eaton Intelligent Power Limited (Eaton Corporation PLC.)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: Cavalier, Donald R., Maines, Garen R.
• Primary Examiner(s): Krause, Justin
• Application Number:
  US12/346,519
• Publication Number:
  US 20100162837A1
• Time in Patent Office: 1,379 Days
• Field of Search: 244/99.3, 244/213, 200/11.TC, 744/12.TA, 74/892.3, 74/892.6, 74/893.7, 74/893.9
• US Class Current: 74/89.23
• CPC Class Codes: F16H 2025/2081 Parallel arrangement of drive motor to screw axis
• CPC Class Codes: F16H 25/22 with balls, rollers, or similar members between the co-operating parts; Elements essential to the use of such members
• CPC Class Codes: Y10T 74/18576 including screw and nut
• CPC Class Codes: Y10T 74/18704 Means to selectively lock or retard screw or nut
• CPC Class Codes: Y10T 74/19637 with brake means for gearing
• CPC Class Codes: Y10T 74/19744 Rolling element engaging thread
• CPC Class Codes: Y10T 74/19847 torque actuated safety devices

Abstract

A ballscrew assembly for an actuator is provided. In an embodiment, the ballscrew assembly includes a ball nut assembly including a view port; a ballscrew provided within at least a portion of the ball nut assembly; an inner rod provided within the ballscrew in the direction of the longitudinal axis, the inner rod including an enlarged end portion; and a compression mechanism, such that at least a portion of the compression mechanism is provided between the enlarged end portion and the ballscrew. In another embodiment the assembly is configured such that when the inner rod is in a failed state, the compression mechanism provides a force that moves the visual indicator toward the view port. In another embodiment, the assembly includes a proximity sensor in addition to, or in lieu, of a view port to detect a failure.

Claims

1. A ballscrew assembly for an actuator, the ballscrew assembly comprising:

a ball nut assembly, including a ballscrew provided within at least a portion of the ball nut assembly, the ballscrew having a longitudinal axis, a fore end, and an aft end;

an inner rod provided within the ballscrew and extending in the direction of the longitudinal axis;

a proximity sensor positioned behind the aft end of the ballscrew;

wherein, in the event of inner rod separation or ballscrew separation, a spring force forces an aft portion of the separated inner rod or separated ballscrew toward the proximity sensor.

2. The assembly of claim 1, wherein the proximity sensor comprises an inductive proximity sensor.

3. The assembly of claim 1, wherein the assembly includes an inner torque tube.

4. The assembly of claim 3, including an outer torque tube, wherein, in the event of separation of the inner torque tube, the outer torque tube is configured to prevent rotation of the ballscrew.

5. The assembly of claim 1, the assembly including a clutch, rollers, and bearings.

6. The assembly of claim 1, the assembly including a differential gear assembly.

7. The assembly of claim 6, including two motors, wherein the differential gear assembly is configured to transmit an average torque.

8. The assembly of claim 1, including a DC motor.

9. The assembly of claim 8, wherein the DC motor is a brushless motor with an integral electromechanical brake.

10. The assembly of claim 1, further comprising a first spring mechanism and a second spring mechanism wherein in the event of ballscrew separation, the first spring mechanism forces an aft portion of the separated ballscrew toward the proximity sensor, and in the event of inner rod separation, a second spring mechanism forces an aft portion of the separated inner rod toward the proximity sensor.

11. The assembly of claim 10, wherein the first spring mechanism provides a larger comparative force than the second spring mechanism.

12. The assembly of claim 10, wherein the first spring mechanism and the second spring mechanism comprise a compression spring.