Spring devices – Resilient shock or vibration absorber – Including energy absorbing means or feature
Reexamination Certificate
1999-07-28
2002-03-05
Swann, J. J. (Department: 3611)
Spring devices
Resilient shock or vibration absorber
Including energy absorbing means or feature
C267S120000
Reexamination Certificate
active
06352246
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a liquid filled vibration isolator for use in, for example, an engine mount of a car body.
Hitherto, a liquid filled vibration isolator of the above-described type has been configured, for example, as shown in
FIGS. 12
to
14
. The liquid filled vibration isolator includes an inner cylindrical metal member
1
and a cylindrical intermediate metal member
2
. The intermediate metal member
2
is disposed around the inner cylindrical metal member
1
at a distance spaced apart from the inner cylindrical metal member
1
. The inner cylindrical metal member
1
and the cylindrical intermediate metal member
2
are coaxially disposed. The cylindrical intermediate metal member
2
has a pair of ring portions
2
a,
disposed at the two axial ends of the cylindrical intermediate metal member
2
, and a connecting portion
2
b
for integrally connecting the ring portions
2
a
to each other. The connecting portion
2
b
has a cross section formed in a circular-arc-like shape, the cross section being a cross section in a direction perpendicular to the radial connecting portion
2
b
axis. The diameter of the connection portion
2
b
is smaller than the diameter each of the ring portions
2
a.
The connection portion
2
b
has one opening
2
c
formed in a direction in which main vibrations are input. A cylindrical rubber member includes a pair of side walls
3
a
for connecting the two axial directional ends of the cylindrical intermediate metal member
2
and the inner cylindrical metal member
1
to one another. Moreover, the rubber member includes an arm portion
3
b
extending between the side walls
3
a
at a position on the inside of the connection portion
2
b
in the axial direction. Thus, the arm portion
3
b
connects the connection portion
2
b
and the inner cylindrical metal member
1
to each other. The rubber member has a thin diaphragm portion
3
c
disposed on the outside of the connection portion
2
b
such that a gap
3
d
is created between the connection portion
2
b
and the thin diaphragm portion
3
c.
The diaphragm portion
3
c
extends between two opposite side portions in the axial direction of the liquid filled vibration isolator. In addition, the rubber member has a recess
3
e
surrounded by the pair of side walls
3
a
and the arm portion
3
b
and the recess
3
e
is opened in the opening
2
c.
A passage forming member
4
joins the pair of ring portions
2
a.
The passage forming member
4
closes the opening
2
c
in the connection portion
2
b
and has a shape extending on the two sides in the circumferential direction.
As shown in
FIG. 15A
, the passage forming member
4
includes a circular-arc plate
4
a
having a width slightly larger than the opening
2
c
in a part of the connection portion
2
b.
Moreover, a plurality of partition walls
4
b
are disposed on the outside of the circular-arc plate
4
a
at positions between the two sides thereof (the two sides included) in the widthwise direction such that the distances between the partition walls
4
b
are substantially the same and the partition walls
4
b
alternately extend from each of the two ends of the circular-arc plate in the circumferential direction. Moreover, end walls
4
c
stand erect at the two ends of the circular-arc plate
4
a
in the circumferential direction. Thus, a reciprocative passage
4
d
is formed. The reciprocative passage
4
d
reciprocates between the two ends of the circular-arc plate
4
a
in the circumferential direction. Referring to
FIG. 15A
, a first communication opening
5
a,
which is allowed to communicate with the recess
3
e,
is formed at a first end of the reciprocative passage and a second communication opening
5
b,
which is allowed to communicate with the gap
3
d,
is formed at a second end of the reciprocative passage
4
d.
As shown in
FIG. 13
, an upper stopper member
6
a,
made of rubber to have elasticity, is molded on the reverse side of the passage forming member
4
by vulcanization. A lower stopper member
6
b
is disposed on the inside of the upper stopper member
6
a
an is made of resin.
An outer cylindrical metal member
7
, which includes a rubber seal
7
a
on the inner surface thereof, is coaxially disposed on the outside of the cylindrical intermediate metal member
2
. The outer cylindrical metal member
7
is being secured to the cylindrical intermediate metal member
2
via drawing process. The outer cylindrical metal member
7
closes the space from the cylindrical intermediate metal member
2
in a fluid-tight manner so that a main liquid chamber
8
a
is formed in the recess and a sub-liquid-chamber
8
b
is formed in the gap
3
d.
In addition, an orifice passage
8
c
is formed in a space within the passage forming member
4
to allow the main liquid chamber
8
a
and the sub-liquid-chamber
8
b
to communicate with each other.
When in use, the inner cylindrical metal member
1
of the liquid filled vibration isolator is connected to a support member (not shown) of a car body and the outer cylindrical metal member
7
is connected to a support member (not shown) adjacent to the engine of the car. The upper and lower stopper members
6
a,
6
b
are disposed in the vertical direction (i.e., the direction in which the main vibrations of the engine are input). In addition, the main liquid chamber
8
a
and the sub-liquid-chamber
8
b
are disposed in the vertical direction across the inner cylindrical metal member
1
. If vibrations are produced between the inner cylindrical metal member
1
and the outer cylindrical metal member
7
, the elastic action of the rubber member and the resonant action of the liquid column (i.e., via liquid which flows in the orifice passage
8
c
) damp the vibrations.
Since the passage forming member
4
of the liquid filled vibration isolator is made of metal, such as an aluminum die-cast, a problem arises in that the weight of the liquid filled vibration isolator becomes heavier as the absolute length of the orifice passage is elongated. The passage forming member
4
, joined to the cylindrical intermediate metal member
2
, is immersed in a liquid to fill the inside portion of the recess
3
e
and similar the liquid. Then, the outer cylindrical metal member
7
, disposed on the outer surface of the cylindrical intermediate metal member
22
is subjected to the drawing process in the liquid. Since only one opening (i.e., the communication opening) of the passage forming member
4
, which is allowed to communicate with the recess
3
e,
is provided, air in the main liquid chamber
8
a
cannot easily be discharged. Thus, a long time is required to complete the liquid filling operation. Another problem arises in that residual air in the main liquid chamber
8
a
deteriorates the performance for isolating vibrations.
SUMMARY OF THE INVENTION
To overcome the foregoing above-described problems, an object of the present invention is to provide a liquid filled vibration isolator which can easily and reliably be filled with liquid and which enables the weight of a passage forming member thereof to be reduced.
To achieve the foregoing object, according to one aspect of the present invention, a liquid filled vibration isolator comprising: an inner cylindrical metal member; a cylindrical intermediate metal member disposed on the outside of the inner cylindrical metal member at a position apart from the inner cylindrical metal member and incorporating paired ring portions formed at two ends in the axial direction, a connection portion for integrally connecting the paired ring portions to each other and an opening formed in a direction in which main vibrations are input; a rubber member constituted by paired side wall portions for connecting the paired ring portions of the intermediate metal member and the inner cylindrical metal member to each other, an arm portion for connecting the paired side wall portions in an axial direction to connect the connection portion and the inner cylindrical metal member, a recess surrounded by the paired side
Divine David
Swann J. J.
Tokai Rubber Industries Ltd.
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