Spring devices – Resilient shock or vibration absorber – Including energy absorbing means or feature
Reexamination Certificate
2000-12-28
2002-09-03
Lavinder, Jack (Department: 3683)
Spring devices
Resilient shock or vibration absorber
Including energy absorbing means or feature
C267S219000
Reexamination Certificate
active
06443438
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fluid-sealed anti-vibration device which is used in an engine mounting and the like.
2. Description of the Prior Art
A cone-shaped mounting is known in the prior art wherein a first connecting member secured to a vibration generating side, a second connecting member secured to a vibration receiving side, and a substantially cone-shaped elastic body member for connecting the first and second connecting members are provided, and provided inside the elastic body member is a fluid chamber, of which part of an elastic wall is the elastic body member and which is divided by a partition member into a main fluid chamber and a sub-fluid chamber, and a first orifice passage is provided for communicating with both fluid chambers.
Also, a cylindrical bushing is also known in the prior art wherein inner and outer cylindrical tubes are connected by an elastic member, a plurality of fluid chambers divided by the elastic member in the circumferential direction is provided, and an orifice passage is arranged to communicate with these fluid chambers.
As a cone-shaped mounting, a fluid sealed type anti-vibration rubber device which is provided with a partition member for dividing its inner part into a main fluid chamber and a sub-fluid chamber, a part of which is an elastic membrane which is deformed elastically with change in the internal pressure of the main fluid chamber and an orifice passage provided extending to the partition member for communication between the main fluid chamber and the sub-fluid chamber is known. In the mounting, a partition member comprises an elastic partition member which is integrally formed with an elastic membrane and an orifice portion formed around the elastic membrane and interposed between a first supporting member and a second supporting member, and a boundary portion of the elastic membrane and the orifice portion is clamped by the first supporting member and the second supporting member (see FIG.
4
).
In the construction of the mounting, when a stepped portion is formed by projecting upward the central portion of the first supporting member positioned at a main fluid chamber side, a fluid mass section enclosed by this stepped portion is formed on the elastic membrane and the fluid mass section and the main fluid chamber communicate through an opening portion which is provided in this stepped portion, the elastic membrane is deformed elastically by the vibration input to the main chamber, fluid column resonance is generated in this fluid mass section and originating from this fluid column resonance, the maximum value (hereinafter called the peak) and the minimum value (hereinafter called the bottom) can be formed for a dynamic spring characteristic. Thereby, a low dynamic spring effect can be achieved in a wide frequency region.
Decrease in vibration based on flow of a fluid between fluid chambers in the cone-shaped mount is used to decrease the vibration, for example, in the vertical direction (hereinafter referred to as “the Z-axis direction”) among vibrations in three axial directions consisting of X, Y, and Z axes at right angles to one another. and therefore the decrease in vibration does not affect the front and rear direction (hereinafter referred to as “the X-axis direction”) and the right and left direction (hereinafter referred to as “the Y-axis direction”).
In the case of the decrease in vibration based on liquid flow between the fluid chambers in the cylindrical bushing, when the axial direction of the cylindrical bushing is adjusted to the Z-axis direction, if four fluid chambers are formed at intervals of 90° in the circumferential direction and each fluid chamber is arranged in the directions of the X and Y axes, vibrations in each of the X and Y-directions can be decreased by one cylindrical bushing, but the vibration in the Z-axis direction can not be decreased.
Accordingly, to decrease all vibrations in the directions of the three axes, X, Y, and Z, when for example, the cone-shaped mounting and the cylindrical bushing are combined, more than one fluid-sealed anti-vibration device must be provided. In this case, the number of devices becomes many and their arrangement is complicated, increasing the total weight and cost of the device. It is therefore an object of the present invention to decrease all vibrations in the directions of the three axes, X, Y, and Z by the vibration decrease, based on the liquid flow between the fluid chambers in one fluid-sealed anti-vibration device.
Also, in the construction of the cone-shaped mounting, a partition member comprises an elastic partition member interposed between a first supporting member and a second supporting member, a boundary portion of the elastic membrane and the orifice portion is clamped by the first and supporting member, and tension of the elastic member is decided by the clamping amount, that is, a clamping overlap width. Resonance frequency of the elastic membrane portion is decided by tension thereof.
If the resonance frequency of the elastic membrane portion can be tuned by controlling the clamping width, fluid column resonance in the fluid mass section can be freely tuned through optional tuning of the resonance frequency of the elastic membrane portion. However, the controlling of the clamping width feasible only in the direction which lowers its tension by reducing the clamping width. It is therefore desired to enlarge the tuning width, as it is relatively narrow.
Further, when the stepped portion projecting from the first supporting member into the main fluid chamber and a bevel member vibrating within the main fluid chamber in an integral manner with the elastic body member, it is necessary to secure a certain clearance h between the bevel member and the stepped portion. Therefore, the overall height of the engine mount becomes high and the size becomes large, correspondingly. It is therefore an object of the present invention to expand the tuning width of resonance frequency of the elastic membrane and realize an entire fluid sealed anti-vibration device compact in size.
SUMMARY OF THE INVENTION
The primary object of the present invention is to overcome the above-mentioned problems and to provide a fluid-sealed anti-vibration device comprising a cone-shaped mounting section and a cylindrical bushing section, wherein the cone-shaped mounting section comprises a first connecting member secured to a vibration generating side, a second connecting member secured to a vibration receiving side, a substantially cone-shaped elastic body member for connecting the first and second connecting members, a fluid chamber of which part of an elastic wall is the elastic body member and which is divided by a partition member into a main fluid chamber and a sub-fluid chamber, and a first orifice passage for communicating with the main and sub-fluid chambers, and the cylindrical bushing section comprises a plurality of side fluid chambers which are provided in a circumferential direction at a predetermined intervals on the outer circumference of the elastic body member and of which part of an elastic wall is the elastic body member, and a second orifice passage for communicating with each of the side fluid chambers, characterized in that the cylindrical bushing section and the cone-shaped mounting section are integrally provided.
According to a second object of the present invention, the cylindrical bushing section is provided with the side fluid chambers and open recess chambers which are alternately formed in the circumferential direction, and a bottom section of the recess chamber is a thin section of the elastic body member in the cone-shaped mounting section.
According to a third object of the present invention, the side fluid chambers are paired at intervals of 180° in the circumferential direction, each of which is arranged in the front and rear direction of a car body.
According to a fourth object, the cone-shaped mounting section and the cylindrical bushing section use the first and second connecti
Sakamoto Toru
Satori Kazutoshi
Birch & Stewart Kolasch & Birch, LLP
Lavinder Jack
Sy Mariano
Yamashita Rubber Kabushiki Kaisha
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