Elastomer vibration isolator bushing

Abstract: An elastomer bushing (10) is provided to reduce shear load on an elastomer bond (20). An inner metal cylinder (12) is coupled to a first component and an outer metal cylinder (14) is coupled to a second component. An elastomer material (16) is disposed between the inner and outer metal cylinders to create an elastomer bond (20). End lugs (18) are formed integral with the inner and outer metal cylinders (12, 14) to reduce the shear load on the elastomer bond (20) by taking up elastomer load into compression of the elastomer (16).

Description: The present invention relates to a structure for reducing shear load on an elastomer bond and a method for reducing that shear load according to the preamble of claim 1 and according to the preamble of claim 6, respectively, see US-A-2 221 884. Elastomer bushings are used in oil tank mount systems to dampen resonances and reduce vibratory loads on tank and brackets. The elastomer is effective in detuning resonances in the engine operating range. The elastomer bushings are constructed of two concentric metal cylinders, with an epoxy or other rubber member interposed between the cylinders. The metal cylinders provide necessary rigidity to the bushing. The elastomer or rubber provides the required spring rate and decoupling/vibration isolation between the structures. For example, then, an elastomer bushing may be used between oil tank and engine frame structures. In operation, the relative motion between oil tank and engine frame, or other structures, induces shear loads on the elastomer to metal cylinder bonds of the bushing. This causes the bond to deliminate or fail over time. It would be desirable, then, to improve the bushing life of elastomer bushings used to dampen resonances and reduce vibratory loads in mechanical system To improve bushing life, the present invention proposes reducing shear load on the elastomer epoxy bond to metal cylinders. This is accomplished by the features of claim 1 as well as by the features of claim 6. Accordingly, the present invention provides an effective technique for improving bushing life for mechanical system components. The invention will now be described in greater detail, by way of example, with reference to the drawing, the single figure of which illustrates an elastomer bushing constructed in accordance with the teachings of the present invention. Referring to Fig. 1, there is illustrated an elastomeric bushing assembly 10. The bushing assembly 10 is typically comprised of inner and outer concentric metal sleeves or cylinders 12 and 14, respectively. A rubber or other elastomer material 16 is disposed between the two cylinders 12 and 14. In a typical bushing application, one cylinder is joined to a movable member and the other cylinder is joined to a support element. The bushing is constructed to permit controlled movement between parts, and to decouple translational and rotational vibrational modes for damping and isolation. The inner cylinder 12 is of an internal diameter chosen to facilitate its mounting requirements. In some applications inner member 12 may be solid or rod-like rather than hollow. While the inner member 12 is commonly made of a metal such as steel, it may also be fabricated from an engineering plastic. The internal diameter of the elastomer member 16 is somewhat less than the outer diameter of the rigid inner member 12. When in an assembled condition, this insures that the fit between the inner member 12 and the elastomeric member 16 forms a proper seal. Additionally, the elastomeric member 16 must interface with the outer member 14 to form the desired seal. The present invention proposes the addition of end lugs 18 to the inner and outer cylinders 12 and 14 of the bushing 10. The end lugs are integral with the inner and outer cylinders 12 and 14, with the entire unit typically manufactured from stainless steel. The end lugs 18 reduce the shear load on the elastomer bond 20 to the metal cylinders 12 and 14. During operation, the relative motion between cylinders 14 and 12 induces separation or shear load in the elastomer to cylinder bond 20. With the addition of end lugs, part of this elastomer separation load is taken up into compression of the elastomer. The total shear load is reduced by the amount of compression. Hence, the end lugs 18 provide a face for the elastomer to bear on. The addition of end lugs to be integral with the cylinders provides the desired load carrying capacity. While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made without departing from the scope of the invention. For example, this design can be applied in various environments to various components.

Claims: A structure (10) for reducing shear load on an elastomer bond (20), the structure comprising comprising: an inner cylinder (12) coupled to a first component; an outer cylinder (14) coupled to a second component; and an elastomeric material (16) disposed between the inner and outer cylinders (12, 14) to create an elastomer bond and to reduce shear load on the elastomer bond (20) by taking up elastomer load into compression of the elastomer; characterized by . end lugs (18) integral with the outer cylinder (14) extending radially inwardly and end lugs (18) integral with the inner cylinder (12) extending radially outwardly, and the radially inwardly directed end lugs (18) being radially spaced from the radially outwardly directed end lugs (18). A structure as recited in claim 1 wherein the elastomer bond (20) provides vibration isolation between the first and second components. A structure as recited in claim 1 wherein the inner and outer cylinders (12, 14) integral with the end lugs (18) are comprised of stainless steel. A structure as recited in claim 1 wherein an internal diameter of the elastomer material (16) is less than an outer diameter of the inner cylinder (12). A structure (10) as recited in claim 1 wherein the elastomeric material (16) interfaces with the inner and outer cylinders (12, 14) to form a seal. A method for reducing shear load on an elastomer bond (20), the method comprising the steps of: providing an inner cylinder (12) and an outer cylinder (14); coupling the inner cylinder (12) to a first component; coupling the outer cylinder(14) to a second component; inserting an elastomer (16) between the inner and outer cylinder (12, 14) to create the elastomer bond (20) characterized by forming end lugs (18) integral with the outer cylinder (14) and extending radially inwardly and by forming end lugs (18) integral with the inner cylinder (12) and extending radially outwardly, and the radially inwardly directed end lugs (18) being radially spaced from the radially outwardly directed end lugs (18) to reduce the shear load on the elastomer bond (20). A method as recited in claim 6 further comprising the step of taking up elastomer load into compression of the elastomer (16). A method as recited in claim 6 further comprising the step of using the elastromer (16) to provide vibration isolation between the first and second components. A method as recited in claim 6 further comprising the step of forming an internal diameter of the elastomer (16) to be less than an outer diameter of the inner cylinder. A method as claimed in claim 7, 8, or 9 further comprising the step of forming an internal diameter of the elastomer (16) to be less than an outer diameter of the inner metal cylinder (12).

Inventors: MAHON WAYNE ERROL, PATEL NIRANJAN JAYANAIBHAI, MAHON, WAYNE ERROL, PATEL, NIRANJAN JAYANAIBHAI
Applicants: GEN ELECTRIC, GENERAL ELECTRIC COMPANY
Application year: 2000
Main classification: F16F1
IPC codes: F16F15, F16F1