RESONANT INERTIAL FORCE GENERATOR HAVING STABLE NATURAL FREQUENCY

• US 20110209958A1
• Filed: 11/04/2009
• Published: 09/01/2011
• Est. Priority Date: 11/04/2008
• Status: Abandoned Application

• Current Assignee: Lord Corporation (Parker-Hannifin Corporation)
• Original Assignee: Lord Corporation (Parker-Hannifin Corporation)
• Inventors: Janowski, Michael D., Badre-Alam, Askari
• Application Number:
  US13/127,559
• Publication Number:
  US 20110209958A1
• Time in Patent Office: Days
• US Class Current: 188/379
• CPC Class Codes: F16F 1/185 characterised by shape or design of individual leaves F16F1/22 takes precedence
• CPC Class Codes: F16F 1/20 with layers, e.g. anti-friction layers, or with rollers between the leaves
• CPC Class Codes: F16F 15/03 using magnetic or electromagnetic means F16F9/53, F16F15/005 take precedence
• CPC Class Codes: F16F 3/12 the steel spring being in contact with the rubber spring F16F1/12 takes precedence
• CPC Class Codes: F16F 7/1011 by electromagnetic means
• CPC Class Codes: F16F 7/104 the inertia member being resiliently mounted F16F7/1022 takes precedence
• CPC Class Codes: Y10T 29/49609 Spring making

Abstract

A resonant inertial force generator for controlling vibrations of a structure includes a compliant spring comprising a stack of flexures and elastomeric shims in alternating arrangement, a driven inertial mass coupled to the compliant spring to generate a vibration controlling force.

Claims

1. A resonant inertial force generator for controlling vibrations of a structure, comprising:

a compliant spring comprising a stack of flexures and elastomeric shims in alternating arrangement;

an inertial mass coupled to the compliant spring; and

an actuator for moving said inertial mass.

2. The resonant inertial force generator of claim 1, wherein said flexures have flexure surfaces adjacent to said elastomeric shims, said elastomeric shims being bonded to said flexure surfaces.

3. The resonant inertial force generator of claim 1, wherein the number of flexures in the stack is at least 2.

4. The resonant inertial force generator of claim 1, which has a natural frequency with a decay less than 0.1 Hz over 3,000 hours of operation.

5. The resonant inertial force generator of claim 1, wherein the actuator is an electromagnetic actuator.

6. The resonant inertial force generator of claim 1, wherein said flexures are comprised of composite beam plates.

7. The resonant inertial force generator of claim 1, wherein said stack is sandwiched between a pair of end plates.

8. The resonant inertial force generator of claim 7, wherein the elastomeric shims at distal ends of the stack are bonded to the end plates.

9. The resonant inertial actuator of claim 1, wherein at least one of the elastomeric shims in the stack has a shape factor greater than 10.

10. A resonant inertial force generator, comprising:

an inertial mass supported by a plurality of flexures; and

a plurality of intermediate elastomeric shims interleaved with said plurality of flexures.

11. The resonant inertial force generator of claim 10, wherein said flexures are comprised of composite plate members.

12. The resonant inertial force generator of claim 11, wherein said flexures have flexure surfaces adjacent to said intermediate elastomeric shims, said intermediate elastomeric shims being bonded to said flexure surfaces.

13. The resonant inertial force generator of claim 11, wherein each of said intermediate elastomeric shims has a shape factor greater than 10.

14. A compliant spring, comprising:

a plurality of composite flexure plates layered in a stack; and

an elastomeric shim disposed between each adjacent pair of the composite flexure plates.

15. The compliant spring of claim 14, wherein the elastomeric shim is bonded to the adjacent pair of the composite flexure plates.

16. The compliant spring of claim 14, wherein said elastomeric shim has a shape factor greater than 10.

17. A method of making an inertial force generator, comprising:

providing an inertial mass;

providing n composite flexures, wherein n is an integer and is greater than 1;

providing at least n+1 elastomeric shims;

interleaving the at least n+1 elastomeric shims with the n composite flexures to form a compliant spring comprising an alternating arrangement of flexures and elastomeric shims;

coupling said inertial mass to the compliant spring; and

coupling to the inertial mass an actuator capable of moving the inertial mass.

18. A method of making an inertial force generator, comprising:

providing an inertial mass;

providing a plurality composite flexures;

providing a plurality of elastomeric shims;

stacking the composite flexures and elastomeric shims alternately to form a compliant spring, the elastomeric shims being arranged adjacent to load bearing areas of the composite flexures;

coupling said inertial mass to said compliant spring; and

coupling to the inertial mass an actuator capable of moving the inertial mass.

19. The method of claim 18, wherein stacking the composite flexures and elastomeric shims alternately to form a compliant spring comprises stacking the composite flexures and elastomeric shims to form a plurality of compliant springs.

20. The method of claim 18 wherein stacking the composite flexures and elastomeric shims alternately to form a compliant spring comprises.

21. A method of making an inertial force generator spring, comprising:

providing a plurality of composite flexure plates;

providing an intermediate elastomer;

layering said composite flexure plates with said intermediate elastomer between said composite flexure plates to provide a spring assembly of layered composite flexure plates and intermediate elastomer between adjacent composite flexure plates, with said intermediate elastomer bonded to said composite flexure plates.

22. A resonant inertial force generator, comprising:

an inertial mass supported by a plurality of composite flexures arranged in a stack; and

compliant means for separating said composite flexures.

23. A resonant inertial force generator for controlling vibrations, comprising:

an inertial mass on a spring assembly;

a motor for moving said inertial mass on said spring assembly, said spring assembly including at least a first non-elastomeric flexure and at least a first intermediate elastomer, said intermediate elastomer bonded with said first non-elastomeric flexure.

24. The resonant inertial force generator of claim 23, wherein said at least a first intermediate elastomer has a shape factor greater than 10.

25. The resonant inertial force generator of claim 23, wherein said non-elastomeric flexure is a composite non-elastomeric flexure, said composite non-elastomeric flexure being comprised of a plurality of reinforcing fibers in a cured matrix.

26. The resonant inertial force generator of claim 23, wherein said non-elastomeric flexure is a non-metallic composite flexure.

27. An apparatus for controlling aircraft vibrations, comprising:

an inertial mass on a spring assembly having a natural frequency NF, an electrically driven motor for moving said inertial mass on said spring assembly, said spring assembly including at least a first composite flexure and a means for inhibiting a decay in said natural frequency NF.

28. An apparatus for controlling aircraft vibrations, comprising:

a driven inertial mass on a spring assembly having a natural frequency NF with the spring assembly including a plurality of nonhomogeneous composite flexures having first ends and distal second ends with a plurality of elastomeric spacers bonded between the composite flexures proximate the first ends and the distal second ends.