US 5,687,948 A · Vibration isolation system including a passive tuned vibration absorber

Abstract

An isolation system (20) including the combination of an elastomeric mount (25) for attachment between a structure (24) and a vibrating member (22) and further including at least one passive tuned vibration absorber (TVA) (32) attached in the proximity the elastomeric mount (25) but on the structure side thereof. The resonant frequency f.sub.r of the passive TVA (32) is tuned to a resonant frequency f.sub.r just below the predominant operating frequency f.sub.o of the vibrating member (22), such that the resonance of the tuned vibration absorber (32) makes the structure (24) appear dynamically stiffer. In particular the ratio of f.sub.r /f.sub.o is in the range of between about 0.90 and 0.90. In one embodiment, the passive TVA (32) attaches directly to the inner member (28) of the elastomeric mount (25) and clamps the TVA assembly (43) to the structure (24) and clamps the structure (24) to the elastomeric mount (25). In another embodiment, the passive TVA (32) is clamped to the structure (24) at a point where it cooperates with the elastomeric mount (25) to reduce transmitted vibration, preferably the TVA (32) is attached at a point within last 20% of the end of the beam-like structure (24).

Claims20

Dependent claims

An isolation system for reducing a vibration transmitted from a vibrating member such as an engine into a structure at an operating frequency f.sub.o or within a narrow frequency range about f.sub.o, said isolation system comprising:

(a) an elastomeric mount including:
(i) an outer member with means for attachment to said vibrating member;
(ii) an inner member with means for attachment to said structure;
(iii) a flexible elastomer section interconnected between said outer member and said inner member thereby allowing relative movement between said inner member and said outer member and static load carrying therebetween;
and
(b) two passive tuned vibration absorbers each exhibiting a same resonant frequency f.sub.r which are attached directly to said inner member of said elastomeric mount, each said passive tuned vibration absorber including:
(i) a free-floating tuning mass;
(ii) a rigid member disposed adjacent said tuning mass and directly attached to said inner member;
(iii) a shear elastomer spring interconnected between said rigid member and said tuning mass, said shear elastomer spring and said tuning mass being selected such that said resonant frequency f.sub.r is less than said operating frequency f.sub.o, said shear elastomer spring stressed in operation to be loaded in substantially pure shear and said resonant frequency f.sub.r of said two passive vibration absorbers being tuned such that a ratio of f.sub.r /f.sub.o is in the range between about 0.90 and 0.99.

6 more elements

In combination with a vibrating member supported relative to a beam-like structure, an isolation system for reducing a vibration transmitted at an operating frequency fo from said vibrating member into said beam-like structure having a beam length L and a beam end, said isolation system comprising the combination of:

(a) an elastomeric mount attached adjacent said beam end, including:
(i) an outer member with means for attachment to said vibrating member;
(ii) an inner member with means for attachment to said structure;
(iii) a flexible elastomer section interconnected between said outer member and said inner member thereby allowing relative movement between said inner member and said outer member and support of loads therebetween;
and
(b) a passive tuned absorber assembly including two passive tuned vibration absorbers each exhibiting a resonant frequency f.sub.r, and a pin-like inner member attached to said two passive tuned vibration absorbers, said tuned absorber assembly being clamped through a through bore formed in said beam-like structure proximate said elastomeric mount and within 0.2 L of said beam end of said beam-like structure, each said passive tuned vibration absorber including:
(i) a flee-floating tuning mass;
(ii) a rigid member disposed adjacent said tuning mass;
(iii) an elastomer spring interconnected between said rigid member and said free-floating tuning mass, said elastomer spring and said free-floating tuning mass being selected such that said resonant frequency f.sub.r is less than said operating frequency f.sub.o and a ratio of f.sub.r /f.sub.o of said tuned absorber assembly is between the range of about 0.90 and 0.99.

6 more elements

Dependencies are inferred from the claim text.

Vibration isolation system including a passive tuned vibration absorber

Life of this patent

Vibration isolation system including a passive tuned vibration absorber

Life of this patent

Abstract

Claims20