Spring devices – Resilient shock or vibration absorber – Including energy absorbing means or feature
Reexamination Certificate
2001-01-05
2003-07-29
Lavinder, Jack (Department: 3683)
Spring devices
Resilient shock or vibration absorber
Including energy absorbing means or feature
C267S141200, C267S219000
Reexamination Certificate
active
06598863
ABSTRACT:
This application is based on Japanese Patent Application No. 2000-12515 filed Jan. 21, 2000, the contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to a fluid-filled cylindrical elastic mount which provides a desired vibration damping or isolating effect, utilizing flow of a fluid contained therein, and more particularly to such a cylindrical elastic mount which is easy to manufacture, and which prevents undesirable deformation of components upon assembling these components, thereby exhibiting high stability in quality and improved vibration damping and isolating characteristics of the mount. The present invention is also relates to method of producing the cylindrical elastic mount.
2. Description of the Related Art
A cylindrical elastic mount is known as a vibration damper interposed between two member of a vibration system, to flexibly connecting two members or flexibly mounting one of the two members on the other member. As disclosed in JP-A-10-153233, for example, the cylindrical elastic mount includes a center shaft member and an intermediate metal sleeve member which are disposed in coaxial or eccentric relation with each other, with a suitable radial spacing therebetween, and are connected to each other by an elastic body interposed between the two members. The elastic body has a plurality of pockets formed at respective circumferential portions thereof, which pockets are open in an outer circumferential surface of the intermediate metal sleeve through a plurality of windows formed through the intermediate metal sleeve, respectively. The elastic mount further includes an outer sleeve member which is fitted on the intermediate sleeve so as to close the plurality of windows and which cooperates with the plurality of pockets to define a plurality of fluid chambers filled with a non-compressible fluid, and an orifice member to define orifice passages through which the plurality of chambers communicate with each other. The fluid-filled cylindrical elastic mount as described above utilizes an effect of flow of the fluid, more specifically, the resonance of the fluid flowing through the orifice passage, so as to exhibit a high vibration damping or isolating effect with respect to a vibrational load receiving in directions perpendicular to an axis of the shaft member. This type of elastic mount has been favorably used as an engine mount for a motor vehicle, for example.
The outer sleeve member is fitted on the intermediate metal sleeve by a suitable method. For instance, the outer sleeve member is disposed radially outwardly of the intermediate metal sleeve with a slight radial spacing therebetween. The outer sleeve member is radially inwardly compressed so as to reduce its diameter by effecting a suitable drawing operation which is performed by using eight drawing dies disposed around the outer sleeve member. Thus, the outer sleeve member is fixedly fitted on the outer circumferential surface of the intermediate metal sleeve, thereby closing the openings of the pockets. Alternatively, the outer sleeve member is fitted on the intermediate metal sleeve by a press-fitting operation to press-fit the intermediate metal sleeve in the bore of the outer sleeve member, thereby closing the openings of the pockets. The press-fitting operation permits a rapid and easy assembling of the outer and intermediate sleeve members in comparison with the drawing operation. Further the press-fitting operation may be usable upon assembling an illegally shaped outer sleeve member, such as an outer sleeve including a bracket portion formed as an integral part thereof, with the intermediate metal sleeve.
However, the conventionally employed press-fitting operation, may suffer from inherent problems. Namely, the intermediate metal sleeve member is subjected to resistance force and frictional force applied thereto in its axial direction, upon press-fitting the intermediate metal sleeve member in the bore of the outer sleeve member. This may possibly causes undesirable deformation of the intermediate metal sleeve, especially in circumferential portions where the plurality of windows are formed, since the provision of the windows leads to reduction in a substantial axial dimension and mechanical strength of the intermediate metal sleeve member. The undesirable deformation of the intermediate sleeve not only effects adversely on spring characteristics of the elastic body member, but also possibly causes insufficient fluid-tight sealing between the intermediate and outer sleeve members and a resultant leakage of the fluid from the mount. The conventional elastic mount suffers from a problem of a relatively high ratio of rejects, due to this undesirable deformation of the intermediate metallic sleeve member.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a fluid-filled cylindrical elastic mount which is novel in construction and which is capable of preventing undesirable deformation of an intermediate sleeve member, upon press-fitting the intermediate sleeve member in an outer sleeve member, so that the desired elastic mount can be produced with high stability and ease.
It is another object of the invention to provide a method of producing such a fluid-filled cylindrical elastic mount as described just above.
The first object may be achieved according to the following modes of the invention each of which is numbered like the appended claims and depends from the other mode or modes, where appropriate, to indicate possible combinations of elements or technical features of the invention. It is to be understood that the present invention is not limited to those modes of the invention and combinations of the technical features, but may otherwise be recognized based on the thought of the present invention that disclosed in the whole specification and drawings or that may be recognized by those skilled in the art in the light of the disclosure in the whole specification and drawings.
(1) A fluid filled cylindrical elastic mount including: (a) a center shaft member; (b) an intermediate sleeve member disposed radially outwardly of the center shaft member, the intermediate sleeve member having a plurality of windows formed therethrough, and having a circumferential groove formed in an axially intermediate portion thereof and being open in an outer circumferential surface thereof; (c) an elastic body interposed between the center shaft member and the intermediate sleeve member and having a plurality of pockets formed at respective circumferential positions thereof, the plurality of pockets being open in an outer circumferential surface of the intermediate sleeve member through the plurality of windows, respectively; (d) an outer sleeve member fitted on the intermediate sleeve member so as to close the plurality of windows and cooperating with the plurality of pockets to define a plurality of fluid chambers which are filled with a non-compressible fluid; and (e) an orifice member for defining an orifice passage for fluid communication between the plurality of fluid chambers, the orifice member being disposed in at least one of the plurality of windows so as to extend over an entire circumferential length of the at least one window, and being supported by the intermediate sleeve member such that circumferential opposite end portions of the orifice member are fitted in the circumferential groove on the sides of circumferentially opposite edges of the at least one window, respectively, while having an orifice groove which is formed and open in an outer circumferential surface of said orifice member that is fluid-tightly closed by the outer sleeve member to thereby provide the orifice passage. The orifice member has an axial length which varies in the circumferential direction thereof such that the orifice member is held in abutting contact with axially opposite edges of said at least one of the plurality of windows in a circumferentially intermediate portion of the at least one window,
Lavinder Jack
Rossi & Associates
Tokai Rubber Industries Ltd.
Williams Thomas J.
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