Spring devices – Resilient shock or vibration absorber – Including energy absorbing means or feature
Reexamination Certificate
2002-03-20
2003-12-30
Schwartz, Christopher P. (Department: 3683)
Spring devices
Resilient shock or vibration absorber
Including energy absorbing means or feature
C267S219000, C267S141400
Reexamination Certificate
active
06669182
ABSTRACT:
INCORPORATED BY REFERENCE
The disclosure of Japanese Patent Application No. 2001-102333 filed on Mar. 30, 2001 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to fluid-filled vibration-damping devices such as an engine mount for use in an automotive vehicle, and more particularly to such a fluid-filled vibration-damping device which is capable of exhibiting a vibration damping effect on the basis of flows of a non-compressible fluid filled therein.
2. Description of the Related Art
A fluid-filled vibration-damping device is known as one type of vibration-damping devices including a vibration damping mount or bushing, which is interposed between two members of a vibration system so as to flexibly connect these two members or mount one of these members on the other member in a vibration damping manner. Such a fluid-filled vibration-damping device is capable of exhibiting a vibration damping effect with the help of resonance or flows of a non-compressible fluid filled in its interior space. Since the fluid-filled vibration-damping device includes a plurality of liquid chambers and orifice passages for permitting flows of the non-compressible fluid between these chambers upon application of a vibrational load to the vibration-damping device, it is generally required to house these chambers and orifice passages within the device with high space utilization so that the device is made simple in construction and compact in size in its entirety.
The present assignee has been disclosed in JP-A-2001-50333 an example of the fluid-filled vibration-damping device, in which a first mounting member and a second mounting member having a generally cylindrical configuration are disposed such that one of opposite open-ends of the second mounting member is opposed to the first mounting member with an axial spacing therebetween, and a rubber elastic body elastically connects the first and second mounting members while fluid-tightly closing the one of opposite open-ends of the second mounting member. The disclosed fluid-filled vibration-damping device further includes a movable rubber plate bonded at its peripheral portion to an annular first support member made of metal and a flexible rubber layer bonded at its peripheral portion to an annular second support member made of metal. These movable rubber plate and the flexible rubber layer are assembled with each other in their axial directions with a given axial spacing therebetween while the first and second support members are held in abutting contact with each other at their outer peripheral portions. The movable rubber plate and the flexible rubber layer thus assembled are fixed to the other open-end of the second mounting member by caulking or fluid-tightly crimping the other open-end of the second mounting member against the mutually laminated outer peripheral portions of the first and second support members, thereby fluid-tightly closing the other open-end of the second mounting member. The rubber elastic body and the movable rubber plate cooperate to define therebetween a primary fluid chamber to which a vibrational load to be damped is applied, and the movable rubber plate and the flexible rubber layer cooperate to define therebetween an auxiliary fluid chamber. The primary and auxiliary fluid chambers are both filled with the non-compressible fluid, and are held in fluid communication through an orifice passage that is disposed between the first and second support members so as to extend circumferentially. The disclosed fluid-filled vibration-damping device constructed as described above can exhibit an excellent vibration damping effect by utilizing resonance of the fluid flowing through the orifice passage induced by a pressure difference between the primary and auxiliary fluid chambers generated upon application of the vibrational load to the device.
An extensive study of the disclosed fluid-filled vibration-damping device by the inventors of the present invention reveals that it is effective to divide the auxiliary fluid chamber by a partition member into an intermediate chamber partially defined by the movable rubber plate and an equilibrium chamber partially defined by the flexible rubber layer, and to form another fluid passage for fluid communication between the intermediate chamber and the equilibrium chamber, for thereby enabling the fluid-filled vibration-damping device to exhibit an excellent vibration damping effect over a wide frequency range, on the basis of the flows of the fluid through the orifice and the fluid passages. Described in detail, the fluid passage for fluid communication between the intermediate and equilibrium chambers is tuned to a frequency band that is different from the frequency band to which the orifice passage is tuned, so that the thus modified fluid-filled vibration-damping device can exhibit a desired vibration damping effect on the basis of the resonance of the fluid that is forced to flow through the orifice and fluid passages with respect to vibrations in a plurality of frequency ranges to which the orifice and fluid passages are tuned respectively.
However, the modified fluid-filled vibration-damping device requires an additional manufacturing step for assembling the partition member in the auxiliary fluid chamber, making it cumbersome to manufacture the device. Therefore, the fluid-filled vibration-damping device suffers from a high manufacturing cost and a deteriorated production efficiency.
SUMMARY OF THE INVENTION
It is therefore one object of this invention to provide a fluid-filled vibration-damping device, which is novel in construction, and which makes it possible to easily assemble a partition member into an auxiliary fluid chamber held in fluid communication with a primary fluid chamber through an orifice passage, with simple structure and with high production efficiency, and to effectively form the orifice passage and a fluid passage, which are tuned to different frequency bands. It is another object of the invention to provide a method of producing such a fluid-filled vibration-damping device.
The above and/or optional objects of this invention may be attained according to at least one of the following modes of the invention. Each of these modes of the invention is numbered like the appended claims and depending 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 principle of the invention is not limited to these modes of the invention and combinations of the technical features, but may otherwise be recognized based on the teachings of the present invention disclosed in the entire specification and drawings or that may be recognized by those skilled in the art in the light of the present disclosure in its entirety.
(1) A fluid-filled vibration-damping device comprising: (a) a first mounting member; (b) a second mounting member having a generally cylindrical configuration and being spaced apart from the first mounting member with one of axially opposite open-end portions thereof opposed to the first mounting member; (c) an elastic body elastically connecting the first and second mounting member while fluid-tightly closing the one of opposite open-end portions of the second mounting member; (d) a movable rubber plate bonded at a peripheral portion thereof to an annular first support member; (e) a flexible rubber layer bonded at a peripheral portion thereof to an annular second support member, the movable rubber plate and flexible rubber layer being axially assembled with each other and fixed to an other one of axially opposite open-end portions of the second mounting member by means of caulking of the other one of axially opposite open-end portions of the second mounting member against the first and second support members so as to fluid tightly close the other one of opposite open-end portions of the second mounting member such
Hibi Satoru
Takayanagi Mitsuhiro
Kramer Devon
Rossi & Associates
Schwartz Christopher P.
Tokai Rubber Industries Ltd.
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