Spring devices – Resilient shock or vibration absorber – Including energy absorbing means or feature
Reexamination Certificate
2000-02-29
2002-02-26
Schwartz, Christopher P. (Department: 3613)
Spring devices
Resilient shock or vibration absorber
Including energy absorbing means or feature
C267S219000
Reexamination Certificate
active
06349927
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to a fluid-filled vibration damping device which exhibits a damping effect based on flows of a non-compressible fluid contained therein. More particularly, the invention is concerned with such a fluid-filled vibration damping device having an actuator for suitably controlling or changing damping characteristics of the vibration damping device, and a method of manufacturing the same.
2. Discussion of the Related Art
As one type of a vibration damping device adapted to damp input vibrations based on flows of a fluid contained therein or based on pressure change of the fluid, there is known a fluid-filled vibration damping device capable of controlling or changing its damping characteristics depending upon the input vibrations or other factors, as disclosed in JP-A-08-270718, JP-A-09-280304 and JP-A-05-149370. Such a fluid-filled vibration damping device, in general, includes: (a) a first mounting member; (b) a second mounting member spaced apart from the first mounting member in an axial direction of the second mounting member, and having a generally tubular shape and axially opposite open ends one of which is open toward the first mounting member; (c) an elastic body which elastically connects the first and second mounting members, and which fluid-tightly closes the above-described one of the axially opposite open ends of the second mounting member; (d) a movable member which is displaceable in the axial direction, and which fluid-tightly closes the other of the axially opposite open ends of the second mounting member so as to cooperate with the second mounting member and the elastic body to define a fluid-tight space filled with a non-compressible fluid; and (e) an actuator which displaces the movable member in the axial direction so as to control damping characteristics of the vibration damping device, and which is disposed outwardly of the other of the axially opposite open ends of the second mounting member.
In the above-described conventional vibration damping device, the actuator is attached to the second mounting member by caulking means, or other fixing means such as suitable bolts, as described in the above-described publications, so that the actuator is firmly fixed to a main body of the vibration damping device in which the first and second mounting members are connected by the elastic body to each other and the fluid-tight space filled with the non-compressible fluid is defined by the second mounting member and the elastic body.
For producing the vibration damping device in which the actuator is attached to the main body as described, it is necessary to perform a cumbersome operation such as caulking or a bolt-tightening operation, which would not be necessary if the vibration damping device were not equipped with the actuator. Such a cumbersome operation deteriorates efficiency of the production. Further, the caulking operation requires an exclusive installation or equipment to be performed or used, thereby increasing the production cost.
SUMMARY OF THE INVENTION
It is therefore a first object of the present invention to provide a fluid-filled vibration damping device having a simple construction which permits an actuator to be efficiently attached to its main body by a simple operation such as a press-fitting or drawing operation.
It is a second object of the invention to provide a method of manufacturing the fluid-filled vibration damping device.
The present invention provides a fluid-filled vibration damping device or a method of manufacturing the same according to each of the following aspects, preferred forms or advantageous arrangements of the invention. It is to be understood that the following aspects, preferred forms and advantageous arrangements are provided to facilitate the understanding of possible combinations of features recited in the following aspects, preferred forms and advantageous arrangements, and that the technical features and the combinations of the technical features disclosed in the present specification are not limited to the following aspects, preferred forms and advantageous arrangements, but should be recognized based on the overall description of the specification and the drawings.
The above first object may be achieved according to a first aspect of the present invention, which provides a fluid-filled vibration damping device comprising: (a) a first mounting member; (b) a second mounting member which has a generally tubular shape and which is spaced apart from the first mounting member in an axial direction of the second mounting member, the second mounting member having axially opposite open ends, one of which is open toward the first mounting member; (c) an elastic body which elastically connects the first and second mounting members, and which fluid-tightly closes the one of the axially opposite open ends of the second mounting member; (d) a movable member which is displaceable in the axial direction, and which fluid-tightly closes the other of the axially opposite open ends of the second mounting member so as to cooperate with the second mounting member and the elastic body to define a fluid-tight space filled with a non-compressible fluid; and (d) an actuator which displaces the movable member in the axial direction so as to control damping characteristics of the vibration damping device, and which is disposed on one of axially opposite sides of the second mounting member which is remote from the first mounting member; wherein the improvement comprises: the actuator being provided with a connector which connects the actuator with the second mounting member, the connector having a generally tubular shape and extending from the actuator in a direction toward the above-described one of the axially opposite open ends of the second mounting member, the connector being fitted on an outer circumferential surface of the second mounting member so that the actuator is fixed relative to the second mounting member.
In the fluid-filled vibration damping device constructed according to this first aspect of the invention, it is possible to fix the movable member in an axial portion of the second mounting member which is adjacent to the above-described other of the axially opposite open ends of the second mounting member, by press-fitting the movable member into the axial portion of the second mounting member, or by drawing or plastically deforming the axial portion of the second mounting member radially inwardly thereby forcing the axial portion onto the movable member. Thus, a main body of the vibration damping device, in which the fluid-tight space is defined by the second mounting member, the elastic body and the movable member, can be obtained by the press-fitting or drawing operation without a cumbersome caulking operation. Similarly, it is also possible to fix the actuator to the thus obtained main body, by a press-fitting or drawing operation without a caulking operation. Accordingly, the present vibration damping device advantageously eliminates a conventionally-required, cumbersome caulking operation in the production process and accordingly expensive equipment required for such caulking operation, whereby the production efficiency and cost of the present vibration damping device are remarkably improved and lowered, respectively.
The actuator defined in the present first aspect is not limited to any specific construction, but may be of, for example, a pneumatic actuator which has an enclosed air chamber partially defined by a wall member that is displaceable as a result of change of the pressure in the air chamber, so as to produce mechanical force based on the displacement of the wall member, or alternatively may be of an electromagnetic actuator which has an output member displaceable on the basis of an electromagnetic force or magnetic force. The damping characteristics of the vibration damping device may be controlled, for example, by alternately pressing and moving the movable member onto and away from an opening end of a fluid passag
Burr & Brown
Pezzlo Benjamin A
Schwartz Christopher P.
Tokai Rubber Industries Ltd.
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