Spring devices – Resilient shock or vibration absorber – Including energy absorbing means or feature
Reexamination Certificate
2001-12-27
2003-07-08
Lavinder, Jack (Department: 3683)
Spring devices
Resilient shock or vibration absorber
Including energy absorbing means or feature
C267S140150
Reexamination Certificate
active
06588737
ABSTRACT:
INCORPORATED BY REFERENCE
The disclosure of Japanese Patent Application No. 2000-400983 filed on Dec. 28, 2000 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 an active vibration damping device usable for vibration dampers devices for automotive vehicles, such as an engine mount and a body mount, and capable of actively exhibiting a vibration damping effect or actively offsetting vibrations to be damped. More particularly, the present invention is concerned with a fluid-filled active vibration damping device that includes a pressure receiving chamber partially defined by an oscillating member and filled with a non compressible fluid, and an actuator adapted to oscillate the oscillating member for regulating the pressure of the non-compressible fluid in the pressure-receiving chamber so that the vibration damping device actively exhibits a desired vibration damping effect.
2. Description of the Related Art
A fluid-filed active vibration damping device is known as one type of vibration damping devices, e.g., a vibration damping mount or a vibration damping bushing, which is interposed between two members of vibration system for elastically connecting two members in a vibration damping fashion. As disclosed in JP-A-2-42228, JP-A-10-47426 and JP-A-11-247919, a known example of such a fluid-filled active vibration damping device includes a first and a second mounting member, an elastic body elastically connecting the first and the second mounting members, and partially defining a fluid chamber filled with a non-compressible fluid and adapted to receive a vibration load, an oscillating member partially defining the fluid chamber, and an electromagnetic actuator adapted to oscillate the oscillating member in order to regulate a pressure of the non-compressible fluid in the fluid chamber. The known fluid-filled active vibration damping device is adapted to apply oscillating force corresponding to vibrations to be damped between two members of the vibration system, so as to offset or absorb the vibrations to be damped, or so as to actively change spring characteristics of the vibration damping device corresponding to an input vibration so that the vibration damping device exhibits a low dynamic spring constant with respect to the input vibration. Thus, the fluid-filled active vibration-damping device is capable of exhibiting active vibration damping effects with respect to vibrations to be damped. For the above reasons, the fluid-filled active vibration-damping device has been applied to the engine mount for the automotive vehicles, for example.
In order to ensure a desired vibration damping effect of such a fluid-filled active vibration damping device, it is needed to oscillate the oscillating member at a frequency and a phase that correspond to those of the vibrations to be damped with high accuracy. To meet this requirement, the actuator may be preferably selected from an electromagnetic actuator, a voice-coil type actuator or the like. In general, the actuator may be formed independently of an mounting assembly of the vibration damping device, i.e., an intermediate assembly including the first and second mounting members, the elastic body elastically connecting the first and second mounting members, and the pressure-receiving chamber partially defined by the elastic body. This independently formed actuator is fixedly connected at its power output shaft to the oscillating member of the mounting assembly of the vibration-damping device
In the conventional fluid-filled active vibration damping device as described in the above-indicated documents, the power output shaft of the actuator is fixed to the oscillating member such that the power output shaft is screwed onto a fixing bolt fixed to the oscillating member and extending coaxially with the power output shaft. However, this conventional mechanism for fixing the power output shaft to the oscillating member needs cumbersome and time-consuming operation or processes. Moreover, a reaction force of a twisting force generated upon screwing the power output shaft of the actuator to the fixing bolt fixed to the oscillating member acts on the oscillating member, possibly causing undesirable damage of the oscillating member.
Further, JP-A-6-264955 and JP-A-11-351313 disclose another type of conventional fluid-filled active vibration damping device, in which the oscillating member has a drive shaft fixedly disposed thereon so as to protrudes toward the actuator. The drive shaft of the oscillating member and the power output shaft of the actuator are superposed on each other in a radial direction perpendicular to their axial direction, and fastened together by means of a suitable fastening means, e.g., a bolt and a rivet, which extends through the drive shaft and the power output shaft in the radial direction. In this arrangement, the oscillating member is free from a problem that the oscillating member is undesirably damaged due to reaction force acting thereon upon fixing the drive shaft and the power output shaft together.
However, the conventional fluid-filled active vibration damping device disclosed in JP-A-6-264955 and JP-A-11-351313 suffers from a difficulty in providing a space enough large for executing a required operation for fastening the mutually superposed power output shaft and the drive shaft together by the bolt or rivet extending therethrough. Therefore, the conventional fluid-filled active vibration-damping device still has room for improving in terms of efficiency of manufacturing of the vibration-damping device.
In addition, the actuator used in the conventional fluid-filled active vibration damping device includes a coil to be energized which is fixed to an outer circumferential portion thereof, and an attractive member such as a permanent magnet and a magnetic member disposed within a bore of the coil. In this arrangement, an entire length of a wire winding around the coil is inevitably made long, for ensuring the sufficiently large number of winding of the coil, resulting in a high tendency toward increase of electrical resistance. As a result, the actuator suffers from deterioration of electrical efficiency thereof, so that the actuator becomes incapable of generating a desired oscillating force with high efficiency.
SUMMARY OF THE INVENTION
It is therefore one object of this invention to provide a fluid-filled active vibration damping device which is novel in construction and which makes it possible to assemble a mounting assembly of the vibration-damping device and an actuator formed independently of the mounting assembly to each other with excellent operation efficiency, and a method of producing the same.
It is another object of this invention to provide a fluid-filled active vibration damping device which is novel in construction and which is capable of efficiently generating a relatively large oscillating force with a reduced electric current applied to a coil, and a method of producing the same.
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 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 principle of the 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 whose 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 active vibration damping device comprising: (a) a first and a second mounting member which are spaced apart from each other; (b) an elastic body elastically connecting the first and second mounting
Goto Katsuhiro
Kato Kazuhiko
Lavinder Jack
Pezzlo Benjamin A.
Rossi & Associates
Tokai Rubber Industries Ltd.
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