Spring devices – Resilient shock or vibration absorber – Including energy absorbing means or feature
Reexamination Certificate
2001-07-17
2003-05-06
Rodriguez, Pam (Department: 3683)
Spring devices
Resilient shock or vibration absorber
Including energy absorbing means or feature
C267S141200
Reexamination Certificate
active
06557837
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid-filled cylinder-shaped hydraulic vibration isolator, which can be suitably employed as a suspension bushing, an engine mount, a cab mount, and so on, of an automobile, for example.
2. Description of the Related Art
Conventionally, in a suspension mechanism of an automobile, a liquid-filled cylinder-shaped hydraulic vibration isolator has been known which is employed as a suspension bushing for connecting an automobile body with a suspension arm in a vibration-isolating manner. As illustrated in
FIGS. 6
or
7
, the conventional liquid-filled cylinder-shaped hydraulic vibration isolator comprises a main axial fitting
101
, a stopper
102
, an intermediate cylinder fitting
103
, a rubber elastic body
104
, an outer cylinder fitting
105
, and a cylinder-shaped sealing rubber
106
. The stopper
102
is fixed to an outer periphery of the central portion of the main axial fitting
101
. The intermediate cylinder fitting
103
is disposed outside the main axial fitting
101
coaxially, and includes a pair of ring members
131
,
131
, which are disposed on the opposite ends thereof in the axial direction thereof and two bridging members
132
,
132
, which bridge between both of the ring members
131
,
131
to form two window portions
133
,
133
, which are disposed in the peripheral direction thereof, together with both of the ring members
131
,
131
. The rubber elastic body
104
is interposed between the main axial fitting
101
and the intermediate fitting
103
to connect them integrally, and has two dented portions
144
,
145
, which are opened to the window portions
133
,
133
of the intermediate cylinder fitting
103
. The outer cylinder fitting
105
is disposed outside the intermediate cylinder fitting
103
coaxially, covers the openings of the dented portions
144
,
145
by being subjected to drawing, and forms a main liquid chamber
151
and an auxiliary chamber
152
, which are filled with a liquid “L” and which are communicated with each other by way of an orifice passage
153
, between itself and the dented portions
144
,
145
. The sealing rubber
106
is fastened to an inner peripheral surface of the outer cylinder fitting
105
to seal the liquid “L”, which is filled in the main liquid chamber
151
and the auxiliary liquid chamber
152
.
Note that, in this conventional liquid-filled cylinder-shaped hydraulic vibration isolator, while the main liquid chamber
151
and the auxiliary liquid chamber
152
are immersed in the liquid “L” to be filled therein, the outer cylinder fitting
105
, which is disposed outside the intermediate cylinder fitting
103
coaxially, is reduced diametrically by subjecting it to drawing so that the openings of the respective dented portions
144
,
145
of the rubber elastic body
104
are covered in a liquid-proof manner. Thus, the liquid “L” is filled in the main liquid chamber
151
and the auxiliary liquid chamber
152
.
This conventional liquid-filled cylinder-shaped hydraulic vibration isolator is connected and fixed to an installation portion of either one of the automobile body and the suspension arm, which are to be connected, with the main axial fitting
101
by way of a bolt, etc., and is connected and fixed to an installation portion of the other one thereof by fitting the outer cylinder fitting
105
thereinto by means of pressing, and so on. Thus, the conventional liquid-filled cylinder-shaped hydraulic vibration isolator is disposed so that the main liquid chamber
151
and the auxiliary liquid chamber
152
are positioned along input directions of main vibrations, which are input into the conventional liquid-filled cylinder-shaped hydraulic vibration isolator. When the vibrations are input between the main axial fitting
101
and the outer cylinder fitting
105
in axially perpendicular directions with respect to the thus disposed conventional liquid-filled cylinder-shaped hydraulic vibration isolator, the vibrations can be attenuated effectively by the elastic action of the rubber elastic body
104
and the liquid-pillar resonance action of the liquid “L” which flows by way of the orifice passage
153
between the main liquid chamber
151
and the auxiliary liquid chamber
152
.
By the way, when this conventional liquid-filled cylinder-shaped hydraulic vibration isolator is disposed in an automobile, a load of an automobile body is applied to it as an initial load in the axially perpendicular directions. Along with the application of the initial load, there occurs a tensile strain concentratedly in a part of the rubber elastic body
104
. When the tensile strain thus occurs in the rubber elastic body
104
, the rubber elastic body
104
starts deteriorating at the portion to lessen the strength so that the durability of the liquid-filled cylinder-shaped hydraulic vibrator degrades. Hence, the following operations are carried out generally in order to improve the durability. For instance, after forming the rubber elastic body
104
by vulcanization molding integrally between the main axial fitting
101
and the intermediate cylinder fitting
103
, the rubber elastic body
104
is compressed preliminarily by subjecting an outer peripheral surface of the intermediate cylinder fitting
103
to drawing so as to relieve the tensile strain, which takes place accompanied by the application of the initial load.
In addition, in the conventional liquid-filled cylinder-shaped hydraulic vibration isolator, the sealing rubber
106
, which is fastened to an inner peripheral surface of the outer cylinder fitting
105
, is disposed in order to inhibit the liquid “L”, which is filled in the main liquid chamber
151
and the auxiliary chamber
152
, from leaking. However, the sealing rubber
106
is formed independently of the rubber elastic body
104
. Accordingly, since an additional and independent process is required for forming this sealing rubber
106
by vulcanization molding, it is one of the causes, which result in increasing the manufacturing cost.
On the other hand, it is possible to think of forming the sealing rubber
106
integrally with the rubber elastic body
104
so as to fasten it to an outer peripheral surface of the intermediate cylinder fitting
103
. However, if such is the case, when the preliminary load is applied to the rubber elastic body
104
by subjecting the outer peripheral surface of the intermediate cylinder fitting
103
to drawing as set forth above, the sealing rubber
106
might be damaged by a drawing jig so that there might arise a fear in that it does not fulfil the sealing function, because the drawing is carried out to the intermediate cylinder fitting
103
by way of the sealing rubber
106
.
SUMMARY OF THE INVENTION
The present invention has been developed in view of the aforementioned circumstances. It is therefore an object of the present invention to provide a liquid-filled cylinder-shaped hydraulic vibration isolator, whose manufacturing cost is reduced by disposing a sealing rubber onto an intermediate cylinder fitting and in which the intermediate cylinder fitting is subjected to even drawing without damaging the sealing rubber.
In an aspect of the present invention, a liquid-filled cylinder-shaped hydraulic vibration isolator, which can carry out the aforementioned object, comprises: a main axial fitting; an intermediate cylinder fitting disposed outside the main axial fitting coaxially and including a pair of ring members positioned on the opposite ends thereof in the axial direction thereof and a bridging member bridging between both of the ring members to form a plurality of window portions, disposed in the peripheral direction thereof, together with both of the ring members; a rubber elastic body interposed between the main axial fitting and the intermediate cylinder fitting to connect them integrally and having a plurality of dented portions, opened to the window portions of the intermediate cylinder fitting; an outer cylinder fitting disposed outside the intermediate cyli
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Rodriguez Pam
Tokai Rubber Industries Ltd.
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