Brakes – Inertia of damping mass dissipates motion
Patent
1997-02-03
1999-05-25
Butler, Douglas C.
Brakes
Inertia of damping mass dissipates motion
267136, 26714014, F16F 710
Patent
active
059062541
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND AND SUMMARY OF THE INVENTION
The present invention is directed to active structural vibration control. More particularly, this invention is a flexibly-mounted Active Vibration Absorber (AVA).
In the realm of active noise and vibration control, there are three implementation approaches: active noise control, which uses an inverse-phase sound wave to cancel the disturbance signal; active structural control, which vibrates a structural component at a frequency to cancel the input disturbance (noise and/or vibration); and active isolation control, where an actuator in a mount is reciprocated at the proper frequency, phase and amplitude to cancel the input disturbance (which, again, may be a structural vibration or in the audible range, in which case it is experienced as noise). The active tuned AVA falls in the category of active structural control.
Tuned vibration absorbers are known. These are generally passive systems in which the mass M.sub.2 is chosen to resonate at or near the primary frequency of interest, e.g., the blade pass frequency of a helicopter rotor. The problem with such passive absorber systems has been that the weight penalty paid for their usage was not justified by the level of improvement in performance. Further, the performance was limited by the fact that once the mass was chosen, its effectiveness was restricted to optimization at a single frequency. The system was unable to adapt to changing conditions in order to cancel other frequencies.
The present invention enhances the performance of an active tuned absorber by flexibly-mounting the AVA. Multiple embodiments are shown for shaping the output spectrum of the AVA by various embodiments of flexible-mountings. Further, in another aspect, means for counterbalancing the flexibly-mounted AVA are described.
Various other features, advantages and characteristics will become apparent after a reading of the following specification.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings which form a part of the specification, illustrate several key embodiments of the present invention. The drawings and description together, serve to fully explain the invention. In the drawings,
FIG. 1 is a cross-sectional side view of a schematic depiction of a first hydraulic embodiment of the active vibration absorber of the present invention;
FIG. 2 is a cross-sectional side view of a schematic depiction of a second electromagnetic embodiment of the active vibration absorber;
FIG. 3 is a plot of hypothesized transmissibility curves for passive and active vibration absorber systems;
FIG. 4a is a side schematic view of the flexibly-mounted active vibration absorber system for controlling noise and/or vibration at a predefined location;
FIG. 4b is a plot of hypothesized force transfer function for a theoretically ideal AVA, a real-world AVA, and a flexibly-mounted AVA;
FIGS. 5a and 5b are cross-sectional side views of schematics of two prior art passive tuned absorber assemblies for reducing vibration of an aircraft stiffening member;
FIG. 6a is a partially cross-sectioned side view of a flexibly-mounted active vibration absorber system where the first spring K2b is comprised of flexible beam-like elements manufactured from a spring-steel material;
FIG. 6b is a top view of the first spring K2b which is comprised of multiple flexible beam-like elements;
FIG. 7 is a side view in partial section of a flexibly-mounted active vibration absorber system where the first spring is comprised of multiple stacked belleville washers;
FIG. 8 is a side view of a flexibly-mounted active vibration absorber system where the first spring is comprised of a single sandwich-type elastomer element;
FIG. 9 is a side view of a flexibly-mounted active vibration absorber system where the first spring is comprised of multiple elastomer shear elements;
FIG. 10 is a side view of a flexibly-mounted active vibration absorber system where the first spring is comprised of a cantilever beam designed to have a specific bending stiffness;
FIG. 11 is a side view of a flexibly-
REFERENCES:
patent: 3088062 (1963-04-01), Hudimac
patent: 3487888 (1970-01-01), Adams et al.
patent: 3490556 (1970-01-01), Bennett, Jr. et al.
patent: 4083433 (1978-04-01), Geohegan, Jr. et al.
patent: 4432441 (1984-02-01), Kurokawa
patent: 4565940 (1986-01-01), Hubbard, Jr.
patent: 4610420 (1986-09-01), Fukushima et al.
patent: 4635892 (1987-01-01), Baker
patent: 4693217 (1987-09-01), Beer
patent: 4715559 (1987-12-01), Fuller
patent: 4819182 (1989-04-01), King et al.
patent: 4940914 (1990-07-01), Mizuno et al.
patent: 5251863 (1993-10-01), Gossman et al.
patent: 5265704 (1993-11-01), Landesfeind
patent: 5275388 (1994-01-01), Kobayashi et al.
patent: 5310137 (1994-05-01), Yoerkie, Jr. et al.
patent: 5337864 (1994-08-01), Sjostrom
patent: 5427362 (1995-06-01), Schilling et al.
patent: 5431261 (1995-07-01), Olgac
patent: 5433422 (1995-07-01), Ross et al.
patent: 5439082 (1995-08-01), McKeown et al.
patent: 5447001 (1995-09-01), Nishimura et al.
patent: 5505282 (1996-04-01), Olgac
patent: 5509641 (1996-04-01), Prinzler et al.
patent: 5518108 (1996-05-01), Spurlin
patent: 5529295 (1996-06-01), Leibach et al.
"Operating Guide for the Series 710 Piezoelectric Actuator" Instruction manual from AVC Instrumentation.
White, et al. "An Adaptive Controller for Multivariable Active Noise Control"; Applied Acoustics, 17(1984); pp. 99-109.
Nishimura et al.; An Intelligent Tuned Mass Damper, American Institute of Aeronautics and Astronautics, Inc., A1AA-93-1709-CP:3561-3569 (1993).
Ivers Douglas E.
Jolly Mark R.
Norris Mark A.
Schmidt Warren E.
Butler Douglas C.
Lord Corporation
Wayland Randall S.
LandOfFree
Active systems and devices including active vibration absorbers does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Active systems and devices including active vibration absorbers , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Active systems and devices including active vibration absorbers will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-397010