Self-tuning vibration absorber system and method of absorbing varying frequency vehicle vibrations

• US 6,983,833 B2
• Filed: 05/16/2003
• Issued: 01/10/2006
• Est. Priority Date: 05/16/2002
• Status: Expired due to Fees

• Current Assignee: Lord Corporation (Parker-Hannifin Corporation)
• Original Assignee: Lord Corporation (Parker-Hannifin Corporation)
• Inventors: Ivers, Douglas E., Wilson, Robert W. II
• Primary Examiner(s): WILLIAMS, THOMAS J
• Application Number:
  US10/439,572
• Publication Number:
  US 20040108443A1
• Time in Patent Office: 970 Days
• Field of Search: 188/378, 188/379, 188/380
• US Class Current: 188/379
• CPC Class Codes: B64C 2027/005 using suspended masses
• CPC Class Codes: F16F 7/104 the inertia member being resiliently mounted F16F7/1022 takes precedence

Abstract

A system and method for absorbing vehicle body vibrations is described. The mechanical self-tuning vibration absorber system is utilized to absorb a body vibration with a varying frequency. In a particular application the absorber system provides for absorbing varying frequency vibrations of a helicopter aircraft body. The vibration absorber system utilizes asymmetrical damping to tune the resonant frequency of the system.

Claims

1. A mechanical self-tuning vibration absorber system for a variable vibrating body having a body vibration with a varying frequency, said body vibration having a vibration direction, said mechanical self-tuning vibration absorber system attached to said variable vibrating body, said mechanical self-tuning vibration absorber system having a first absorber unit with a first damping ratio and a second absorber unit with a second damping ratio, said second absorber second damping ratio different from said first absorber first damping ratio, said first absorber unit connected to said second absorber unit wherein said connected first absorber unit and said second absorber unit mechanically walk in a first tuning direction to a low tuned position when said variable vibrating body vibration varying frequency changes to a lower frequency, said first tuning direction perpendicular to said vibration direction, and in a second tuning direction to a high tuned position when said variable vibrating body vibration varying frequency changes to a higher frequency, said second tuning direction perpendicular to said vibration direction.

2. A mechanical self-tuning vibration absorber system as claimed in claim 1 wherein said first damping ratio is greater than said second damping ratio.

3. A mechanical self-tuning vibration absorber system as claimed in claim 1 wherein said mechanical self-tuning vibration absorber system is attached to said variable vibrating body with a mechanical self-tuning vibration absorber system base and said connected first absorber unit and said second absorber unit mechanically walk along a vibration absorber system longitudinal track, said longitudinal track secured proximate to said vibration absorber system base with said first tuning direction away from said base and along said longitudinal beam and said second tuning direction toward said base along said longitudinal beam.

4. A mechanical self-tuning vibration absorber system as claimed in claim 3 wherein an interaction between said first absorber unit and said second absorber unit relative to said lower frequency and a difference between said first damping ratio and said second damping ratio drives said connected first absorber unit and said second absorber unit away from said base.

5. A mechanical self-tuning vibration absorber system as claimed in claim 3 wherein an interaction between said first absorber unit and said second absorber unit relative to said higher frequency and a difference between said first damping ratio and said second damping ratio drives said connected first absorber unit and said second absorber unit towards said base.

6. A mechanical self-tuning vibration absorber system as claimed in claim 1 wherein said first absorber unit has a resonant frequency within the range of body vibration varying frequency.

7. A mechanical self-tuning vibration absorber system as claimed in claim 1 wherein said second absorber unit has a resonant frequency within the range of body vibration varying frequency.

8. A mechanical self-tuning vibration absorber system as claimed in claim 3 wherein said connected first absorber unit and said second absorber unit are comprised of a friction interaction surface, said friction interaction surface movably contacting said vibration absorber system longitudinal track.

9. A method of absorbing vibrations, said method comprising providing a variable vibrating body having a body vibration with a varying frequency, said body vibration having a vibration direction, providing a mechanical self-tuning vibration absorber system with a mechanical self-tuning vibration absorber system base and a mechanical vibration absorber system longitudinal track, said mechanical self-tuning vibration absorber system including a first absorber unit with a first damping ratio and a second absorber unit with a second damping ratio, said second absorber second damping ratio different from said first absorber first damping ratio, said first absorber unit mechanically connected to said second absorber unit, said connected first absorber unit and said second absorber unit movably connected to said mechanical vibration absorber system longitudinal track, attaching said mechanical self-tuning vibration absorber system to said provided body wherein said connected first absorber unit and said second absorber unit mechanically walk in a first tuning direction to a low tuned position when said variable vibrating body vibration varying frequency changes to a lower frequency, said first tuning direction perpendicular to said vibration direction, and in a second tuning direction to a high tuned position when said variable vibrating body vibration varying frequency changes to a higher frequency, said second tuning direction perpendicular to said vibration direction.

10. A method of absorbing vibrations as claimed in claim 9 wherein said first damping ratio is greater than said second damping ratio.

11. A method of absorbing vibrations as claimed in claim 9 wherein said mechanical vibration absorber system longitudinal track is secured proximate to said mechanical self-tuning vibration absorber system base, and attaching said mechanical self-tuning vibration absorber system to said provided body includes attaching said mechanical self-tuning vibration absorber system base to said provided body, with said first tuning direction away from said base and along said longitudinal track and said second tuning direction toward said base along said longitudinal track.

12. A method of absorbing vibrations as claimed in claim 11 wherein an asymmetrical damping phase difference interaction between said first absorber unit and said second absorber unit relative to said lower frequency drives said connected first absorber unit and said second absorber unit away from said base.

13. A method of absorbing vibrations as claimed in claim 11 wherein an asymmetrical damping phase difference interaction between said first absorber unit and said second absorber unit relative to said higher frequency drives said connected first absorber unit and said second absorber unit towards said base.

14. A method of absorbing vibrations as claimed in claim 9 wherein said first absorber unit has a resonance frequency within the range of the body vibration varying frequency.

15. A method of absorbing vibrations as claimed in claim 9 wherein said second absorber unit has a resonance frequency within the range of the body vibration varying frequency.

16. A method of absorbing vibrations as claimed in claim 9 wherein said connected first absorber unit and said second absorber unit include a friction interaction surface, said friction interaction surface movably contacting said track with a walking interaction.

17. A method of making a mechanical self-tuning vibration absorber system for a vibration having a vibration direction, comprising:

providing a mechanical vibration absorber system longitudinal track oriented perpendicular to said vibration direction, providing a first absorber unit with a first damping ratio and a second absorber unit with a second damping ratio, said second absorber second damping ratio different from said first absorber first damping ratio, said first absorber unit connected to said second absorber unit, movably mounting said first absorber unit and said second absorber unit to said mechanical vibration absorber system longitudinal track, wherein said connected first absorber unit and said second absorber unit mechanically walk in a first tuning direction to a low tuned position when excited by a variable vibrating body vibration varying frequency which changes to a lower frequency, said first tuning direction perpendicular to said vibration direction, and in a second tuning opposing direction to a high tuned position when excited by a variable vibrating body vibration varying frequency which changes to a higher frequency, said second tuning direction perpendicular to said vibration direction.

18. A method as claimed in claim 17 wherein said first damping ratio is greater than said second damping ratio.

19. A method as claimed in claim 17, said method including providing a mechanical vibration absorber system base, securing said mechanical vibration absorber system longitudinal track to said mechanical self-tuning vibration absorber system base wherein said first tuning direction is away from said base and along said longitudinal track and said second tuning direction is toward said base along said longitudinal track.

20. A method as claimed in claim 17, wherein an asymmetrical damping phase difference interaction between said first absorber unit and said second absorber unit relative to the vibration frequency drives said connected first absorber unit and said second absorber unit.

21. A method as claimed in claim 17, wherein said first absorber unit has a resonance relative frequency within the range of the body vibration varying frequency and said second absorber unit has a resonance relative frequency within the range of the body vibration varying frequency.

22. A method as claimed in claim 17, wherein said connected first absorber unit and said second absorber unit include a friction interaction surface, said friction interaction surface movably contacting said track with a walking interaction.

23. A method of tracking vibration frequency of a vibrating body having a vibration direction, said method comprising providing a mechanical self-tuning vibration absorber system, said mechanical self-tuning vibration absorber system having a first absorber unit with a first damping ratio and a second absorber unit with a second damping ratio, said second absorber second damping ratio different from said first absorber first damping ratio, said first absorber unit connected to said second absorber unit wherein said connected first absorber unit and said second absorber unit mechanically walk in a first tuning direction to a low tuned position when excited by a variable vibrating body vibration varying frequency changing to a lower frequency, said first tuning direction perpendicular to said vibration direction, and in a second tuning direction to a high tuned position when exposed to a variable vibrating body vibration varying frequency changing to a higher frequency, said second tuning direction perpendicular to said vibration direction, attaching said mechanical self-tuning vibration absorber system to said vibrating body with said first tuning direction and said second tuning direction perpendicular to said vibration direction and observing a position of said connected first absorber unit and said second absorber.

24. A method as claimed in claim 23, said method including monitoring a positional change of said connected first absorber unit and said second absorber.

25. A method as claimed in claim 23, wherein said connected first absorber unit and said second absorber walk along a longitudinal track, said longitudinal track including a plurality of measurement marks.

26. A method as claimed in claim 25, wherein said connected first absorber unit and said second absorber unit include a friction interaction surface, said friction interaction surface movably contacting said track with a walking interaction.

27. A vehicle, said vehicle comprised of a variable vibrating body, said body having a body vibration with a varying frequency, said body vibration having a vibration direction, said body including a mechanical self-tuning vibration absorber system having a first absorber unit with a first damping ratio and a second absorber unit with a second damping ratio, said second absorber second damping ratio different from said first absorber first damping ratio, said first absorber unit connected to said second absorber unit wherein said connected first absorber unit and said second absorber unit mechanically walk in a first tuning direction to a low tuned position when said variable vibrating body vibration varying frequency changes to a lower frequency, said first tuning direction perpendicular to said vibration direction, and in a second tuning direction to a high tuned position when said variable vibrating body vibration varying frequency changes to a higher frequency, said second tuning direction perpendicular to said vibration direction.

28. A vehicle as claimed in claim 27, wherein said first damping ratio is greater than said second damping ratio.

29. A vehicle as claimed in claim 27, wherein said mechanical self-tuning vibration absorber system is attached to said body with a mechanical self-tuning vibration absorber system base and said connected first absorber unit and said second absorber unit mechanically walk along a vibration absorber system longitudinal track, said longitudinal track secured proximate to said vibration absorber system base with said first tuning direction away from said base and along said longitudinal track and said second tuning direction toward said base along said longitudinal track.

30. A vehicle as claimed in claim 27, wherein an asymmetrical damping phase difference interaction between said first absorber unit and said second absorber unit relative to said lower frequency drives said connected first absorber unit and said second absorber unit in said first direction.

31. A vehicle as claimed in claim 27, wherein an asymmetrical damping phase difference interaction between said first absorber unit and said second absorber unit relative to said higher frequency drives said connected first absorber unit and said second absorber unit in said second direction.

32. A vehicle as claimed in claim 27, wherein said first absorber unit has a resonance frequency within the range of body vibration varying frequency and said second absorber unit has a resonance frequency within the range of body vibration varying frequency.

33. A helicopter comprised of a variable vibrating body, said body having a body vibration with a varying frequency, said body vibration having a vibration direction, said body including a mechanical self-tuning vibration absorber system having a longitudinal track and a first absorber unit with a first damping ratio and a second absorber unit with a second damping ratio, said second absorber second damping ratio different from said first absorber first damping ratio, said first absorber unit connected to said second absorber unit wherein said connected first absorber unit and said second absorber unit mechanically walk along said longitudinal track in a first tuning direction to a low tuned position when said variable vibrating body vibration varying frequency changes to a lower frequency, said first tuning direction perpendicular to said vibration direction, and in a second tuning direction to a high tuned position when said variable vibrating body vibration varying frequency changes to a higher frequency, said second tuning direction perpendicular to said vibration direction.

34. A helicopter as claimed in claim 33, wherein said first damping ratio is greater than said second damping ratio and said first absorber unit has a resonance relative frequency within the range of body vibration varying frequency and said second absorber unit has a resonance relative frequency within the range of body vibration varying frequency.

35. A helicopter as claimed in claim 33, wherein an asymmetrical damping phase difference interaction between said first absorber unit and said second absorber unit relative to said frequency drives said connected first absorber unit and said second absorber unit.

36. A method of absorbing vehicle vibrations, said method comprising providing a variable vibrating vehicle body having a body vibration with a varying frequency, said varying frequency in the range of 1–

1,000 Hz, said body vibration having a vibration direction, providing a mechanical self-tuning vibration absorber system with a mechanical self-tuning vibration absorber system base and a mechanical vibration absorber system longitudinal track, said mechanical self-tuning vibration absorber system including a first absorber unit with a first damping ratio and a second absorber unit with a second damping ratio, said second absorber second damping ratio different from said first absorber first damping ratio, said first absorber unit mechanically connected to said second absorber unit, said connected first absorber unit and said second absorber unit movably connected to said mechanical vibration absorber system longitudinal track, attaching said mechanical self-tuning vibration absorber system to said provided vehicle body wherein said connected first absorber unit and said second absorber unit mechanically walk along said longitudinal track in a first tuning direction to a low tuned position when said variable vibrating body vibration varying frequency changes to a lower frequency, said first tuning direction perpendicular to said vibration direction, and in a second tuning direction to a high tuned position when said variable vibrating body vibration varying frequency changes to a higher frequency, said second tuning direction perpendicular to said vibration direction.

37. A method as claimed in claim 36, wherein said connected first absorber unit and said second absorber unit include a friction interaction surface, said friction interaction surface movably contacting said track with a walking interaction.

38. A mechanical self-tuning vibration absorber, said mechanical self-tuning vibration absorber for attachment to a vibrating body having a vibration direction, said mechanical self-tuning vibration absorber having a damped first absorber unit with a first damping ratio and an undamped second absorber unit with a second damping ratio, said undamped second absorber second damping ratio different from said damped first absorber first damping ratio, said damped first absorber unit connected to said undamped second absorber unit wherein said connected damped first absorber unit and said undamped second absorber unit mechanically walk in a first tuning direction to a low tuned position said first tuning direction perpendicular to said vibration direction, and in a second tuning direction to a high tuned position, said second tuning direction perpendicular to said vibration direction.

39. A method of absorbing vibrations, said method comprising the steps of providing a body having a body vibration, said body vibration having a vibration direction, providing a mechanical self-tuning vibration absorber with a mechanical vibration absorber longitudinal track, said mechanical self-tuning vibration absorber including a first absorber unit with a first damping ratio and a second absorber unit with a second damping ratio, said second absorber second damping ratio different from said first absorber first damping ratio, said first absorber unit mechanically connected to said second absorber unit, said connected first absorber unit and said second absorber unit movably connected to said mechanical vibration absorber longitudinal track, attaching said mechanical self-tuning vibration absorber to said provided body wherein said connected first absorber unit and said second absorber unit mechanically walk in a first tuning direction to a low tuned position, said first tuning direction perpendicular to said vibration direction, and in a second tuning direction to a high tuned position, said second tuning direction perpendicular to said vibration direction.

40. A vehicle, said vehicle comprised of a vibrating body, said body having a body vibration with a frequency, said body vibration having a vibration direction, said body including a mechanical self-tuning vibration absorber having a first absorber unit with a first damping ratio and a second absorber unit with a second damping ratio, said second absorber second damping ratio different from said first absorber first damping ratio, said first absorber unit connected to said second absorber unit wherein said connected first absorber unit and said second absorber unit mechanically walk in a first tuning direction to a low tuned position, said first tuning direction perpendicular to said vibration direction, and in a second tuning direction to a high tuned position, said second tuning direction perpendicular to said vibration direction.

41. A helicopter, said helicopter having a vibration direction and including a mechanical self-tuning vibration absorber having a longitudinal track and a damped first absorber unit and an undamped second absorber unit, said damped first absorber unit connected to said undamped second absorber unit wherein said connected damped first absorber unit and said undamped second absorber unit mechanically walk along said longitudinal track in a first tuning direction to a low tuned position, said first tuning direction perpendicular to said vibration direction, and in an opposing second tuning direction to a high tuned position, said second tuning direction perpendicular to said vibration direction.

42. A method of absorbing vehicle vibrations, said method comprising the steps of providing a vibrating vehicle body having a vibration direction, providing a mechanical self-tuning vibration absorber with a mechanical vibration absorber longitudinal track, said mechanical self-tuning vibration absorber including a damped absorber unit and an undamped absorber unit, said damped absorber unit connected to said undamped absorber unit, said connected damped absorber unit and said undamped absorber unit connected to said mechanical vibration absorber longitudinal track, attaching said mechanical self-tuning vibration absorber to said provided vehicle body wherein said connected damped absorber unit and said undamped absorber unit walk along said longitudinal track in a first tuning direction to a low tuned position, said first tuning direction perpendicular to said vibration direction, and in an opposing second tuning direction to a high tuned position, said second tuning direction perpendicular to said vibration direction.