Spring devices – Resilient shock or vibration absorber – Including energy absorbing means or feature
Reexamination Certificate
2000-06-22
2002-08-20
Dickson, Paul N. (Department: 3613)
Spring devices
Resilient shock or vibration absorber
Including energy absorbing means or feature
C267S140110, C267S219000
Reexamination Certificate
active
06435487
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a liquid sealed type vibration isolator used to support a vibration generating member including mainly an automobile engine.
2. Description of the Related Art
The known liquid sealed type vibration isolators, such as an engine mount for supporting a vibration generating member, such as an automobile. engine so that the vibration of the vibration generating member is not transmitted to a body include, for example, a liquid sealed type vibration isolator shown in
FIG. 26
, or a liquid sealed type vibration isolator shown in
FIG. 27
or
28
.
All of these related art liquid sealed type vibration isolators
100
include a metal fixing member
102
to be secured to one of vibration generating member, such as an engine and a support member, such as a body, a metal fixing member
103
to be secured to the other thereof, a vibration isolating base member
104
connecting these two metal fixing members
102
,
103
together and formed of an elastic body of a rubber-like material, a diaphragm
106
provided on the side of the metal fixing member
103
so as to be opposed to the vibration isolating base member
104
, a liquid chamber
105
formed between the vibration isolating base member
104
and diaphragm
106
, and a partition
107
dividing the liquid chamber
105
into two, i.e. a main liquid chamber
105
a
and an auxiliary liquid chamber
105
b
, an orifice
118
communicating the main and auxiliary liquid chambers with each other being formed on an outer circumferential side of the partition
107
to fulfil a vibration damping function of the vibration isolator by an effect of flows of a liquid, which occur owing to the provision of the orifice
118
, in the two liquid chambers, and also a vibration insulating function of the vibration isolator by the vibration isolating base member
104
.
In the case of the liquid sealed type vibration isolator shown in
FIG. 27
or
28
, an elastic film of a rubber-like material
180
is provided in addition to the above-described structure, in a central region of the partition
107
by a vulcanization bonding device or a sandwiching device so as to reduce a dynamic spring constant of a high-frequency region (especially, an engine noise region).
In order to obtain stable product characteristics of such a liquid sealed type vibration isolator, it becomes an important factor that the volume, especially, a cross-sectional area of the orifice having a vibration damping function be set to a desired level.
However, all of the liquid sealed type vibration isolators of
FIGS. 26
,
27
and
28
employ a mode in which an outer circumferential portion of the partition
107
constitutes upper and inner circumferential surfaces and a bottom surface of the orifice, i.e. three sides of a cross section of the orifice, and in which a cylindrical liquid chamber-forming rubber portion
122
, which guides the partition
107
for the press fitting of the same thereinto, and which is on the inner circumferential side of a cylindrical trunk portion
114
of the metal fixing member
103
, constitutes the remaining one side (outer circumferential surface) of the cross section of the orifice.
Therefore, when, especially, the partition
107
is formed by bending one piece of metal plate by pressure molding or deep drawing, a molding process for forming the three sides of a cross section of the orifice becomes complicated.
When the construction of the partition
107
is simplified so that the pressing or deep drawing thereof can be carried out easily, for the purpose of overcoming the difficulties, there is the possibility that problems arise concerning the radial and vertical positioning of the partition. Especially, when a structure like those of the related art vibration isolators of
FIGS. 26
,
27
and
28
is employed in which a lower end portion of the partition
107
is bent radially outward with the resultant outer end portion
171
caulked to a caulking portion of the metal fixing member
103
, i.e. a fastened section
116
formed by a caulking device and formed of the cylindrical trunk portion
114
and a bottom member
113
of the metal fixing member
103
, there is the possibility that the partition
107
slips in the radial and vertical directions due to a tightening force of the caulking device.
When the partition is thus displaced in the radial and vertical directions, the orifice formed by utilizing the partition cannot be set to a desired cross-sectional area, so that stable product characteristics cannot be obtained.
According to an aspect of the present invention, the liquid sealed type vibration isolator is capable of solving these problems, and obtaining stable characteristics.
In the case of the liquid sealed type vibration isolator provided with the elastic film
180
in a central region of the partition
107
which divides the liquid chamber
105
into two, i.e. main and auxiliary chambers, the elastic film setting system has problems different from those encountered in the above-described vibration isolator.
Namely, in the case of the liquid sealed type vibration isolator of
FIG. 27
, the lower end portion of the partition
107
is caulked to the fastened section
116
of one metal fixing member
103
with an upper end portion of a cylindrical side wall
172
expanded and press fitted into an inner circumference of the liquid chamber-forming rubber portion
122
, whereby the orifice
118
is formed between the cylindrical side wall and liquid chamber-forming rubber portion
122
. The elastic film of a rubber-like material
180
is vulcanization bonded to a central opening of a top plate portion
123
of the partition
107
.
In the case of the liquid sealed type vibration isolator of
FIG. 28
, the partition
107
is formed of two partition members
107
a
,
107
b
. The upper partition member
107
a
is of a disc type shape, provided with an opening
173
in a central portion thereof and press fitted in the liquid chamber-forming rubber portion
122
. The lower partition member
107
b
is formed to a shape of an inverted cup, bent radially outward at a lower end portion thereof and caulked at the same portion to the fastened section
116
of the metal fixing member
103
, provided with an opening
175
in a top plate portion
174
thereof, and has the elastic film of a rubber-like material
180
held between the top plate portion
174
and upper partition member
107
a
. A space surrounded by an outer circumferential portion of the upper partition member
107
a
, cylindrical side wall
172
of the lower partition member
107
b
and liquid chamber-forming rubber portion
122
forms the orifice
118
which communicates the main and auxiliary liquid chambers
105
a
,
105
b
with each other.
Regarding a method of setting the elastic film
180
, the partition
107
of the type in which the elastic film
180
is held between two pressing metal members (partition members) shown in the related art example of
FIG. 28
, the shapes of the two partition members are simplified but two metal press dies for the manufacturing of the partition members become necessary. In the case of the partition in the related art example of FIG.
27
of the type which is formed by bending one piece of metal plate, and vulcanization bonding the elastic film
180
to the bent plate, the molding of the partition itself becomes complicated, and a bonding agent application step has to be carried out before the elastic film has been formed. In all of these cases, the cost increases.
According to another aspect of the present invention, the liquid sealed type vibration isolator capable of solving the above-mentioned problems, facilitating the manufacturing of the partition provided with an elastic film thereon, and reducing the manufacturing cost.
SUMMARY OF THE INVENTION
In order to achieve the first-mentioned vibration isolator, the inventors of the present invention earnestly discussed the members by which the orifice should be formed and how to position these members for obtaining a desired cr
Hashimoto Tsutomu
Takaoka Masashi
Takashima Yukio
Dickson Paul N.
Jordan and Hamburg LLP
Pezzlo Benjamin A.
Toyo Tire & Rubber Co., Ltd.
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