Spring devices – Resilient shock or vibration absorber – Including energy absorbing means or feature
Reexamination Certificate
2000-03-16
2002-08-27
Dickson, Paul N. (Department: 3613)
Spring devices
Resilient shock or vibration absorber
Including energy absorbing means or feature
C267S219000
Reexamination Certificate
active
06439554
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention-relates to a switchable liquid-filled vibration isolating mount used to support in a vibration isolating or damping manner a vibrator, such as a power unit and the like of an automobile.
A liquid-filled vibration isolating mount has heretofore been used as a mount for supporting a vibrator, such as an automobile engine so that vibration is not transmitted to a car body.
As a kind of such mount, it has been proposed a switchable liquid-filled vibration isolating mount in which their vibration isolating or damping characteristics are switched from one to another, in accordance with each of two kinds of vibrations in different frequency ranges including shaking vibration and idling vibration (for example, JP-A-1996-270718, JP-A-1998-238586 and JP-A-1998-184777 (Japanese Patent Laid-Open or Unexamined Publication Nos. 270718/1996, 238586/1998 and 184777/1998)).
For example, JP-A-1996-270718, discloses a mount shown in
FIG. 5
herein which has the following construction.
This vibration isolating mounts includes a first rigid fixture
101
; a second rigid fixture
102
having a bottomed barrel shape, a bottom wall of which is spaced apart from the first fixture
101
at a predetermined distance away in the axial direction; a vibration isolating base body
103
interposed between and joining together the first and second fixtures
101
,
102
, and formed of an elastic material such as rubber; a partitioner
104
and first and second diaphragms
105
,
106
disposed in series in the axial direction between the vibration isolating base body
103
and second fixture
102
; a main liquid chamber
107
formed between the vibration isolating base body
103
and partitioner
104
; a sub-liquid chamber
108
formed between the partitioner
104
and first diaphragm
105
; an outer orifice
113
, and an inner orifice
114
positioned diametrically on the inner side of the outer orifice
113
both of which orifices are provided on the partitioner
104
and communicate the main and sub-liquid chambers
107
,
108
with each other, which outer orifice
113
extends to a predetermined length in the circumferential direction of the partitioner
104
, which inner orifice
114
is adapted to be opened and occluded by and with the first diaphragm
105
; a biasing member
127
adapted to bias or elastically press the first diaphragm
105
against the partitioner
104
to thereby prevent a liquid from flowing between the inner orifice
114
and sub-liquid chamber
108
; an equilibrium chamber
109
formed between the first and second diaphragms
105
,
106
; and a switching chamber
110
formed between the second diaphragm
106
and second fixture
102
and capable of receiving an atmospheric pressure and a reduced pressure introduced selectively thereinto, the introduction of a reduced pressure into the switching chamber
110
causing the first diaphragm
105
to be moved against a biasing force of the biasing member
127
and leave the partitioner
104
, and the inner orifice
114
and sub-liquid chamber
108
to communicate with each other, whereby the orifices corresponding to the respective two kinds of vibrations in different frequency ranges can be selectively used.
In this known liquid-filled vibration isolating mount, not only the outer orifice
113
but also the inner orifice
114
opened and occluded by and with the first diaphragm
105
are annularly formed. Because the inner orifice
114
also has some significant length in circumferential direction, a resulted flow resistance suppresses the liquid flow therein. Consequently, because the liquid also flows in the outer orifice
113
, a sufficient vibration damping effect cannot be obtained in the inner orifice
114
.
In order to occlude the inner orifice
114
, a central portion of the first diaphragm
105
is pressed against a lower face of the partitioner
104
by the biasing member
127
. In detail, the planar central portion of the first diaphragm
105
abuts on the planar portion of the partitioner
104
, which planar portion is around an opening
114
a
of the inner orifice
114
and which planar portion is on the side of the sub-liquid chamber
108
. The inner orifice
114
is occluded only by such a plane-to-plane abutting. Therefore, when a pressure of, for example, the interior of the main liquid chamber
107
becomes suddenly high, or when a slight loosening occurs in the engaged portion due to a lateral deviation of the first diaphragm
105
, there is the possibility that the inner orifice
114
is not sufficiently occluded.
BRIEF SUMMARY OF THE INVENTION
The present invention has been made in view of the above-described problems. The present invention provides a switchable liquid-filled vibration isolating mount having basically the same construction as the above-described known liquid-filled vibration isolating mount which has inner and outer orifices, the inner orifice out of which is formed so that it can be opened and closed, and which is capable of selectively using the orifices corresponding to two kinds of vibrations in different frequency ranges, such as shaking vibration and idling vibration, the apparatus according to the invention being formed so that it can solve the aforementioned problems and retain stable characteristics thereof by improving the modes of the two orifices on the partitioner and the shape of the inner orifice-occluding first diaphragm.
The present invention is directed to a switchable liquid-filled vibration isolating mount including, just as the above-described liquid-sealed vibration isolating mount, a first fixture; a second bottomed cylindrical fixture; a vibration isolating base body joining these fixtures together; a partitioner and first and second diaphragms disposed in series between the second fixture and vibration isolating base body; main and sub-liquid chambers separated from each other by the partitioner; outer and inner orifices provided in the partitioner and communicating the two chambers with each other; a biasing member for pressing the first diaphragm against the partitioner; an equilibrium chamber formed between the first and second diaphragms; and a switching chamber formed between the second diaphragm and second fixture; the partitioner between the main and sub-liquid chambers having an opening as the inner orifice extending therethrough in the axial direction; the first diaphragm being provided with a valve body having a projection coaxial with and adapted to be fitted in the opening as the inner orifice; the switching chamber being formed so that either a reduced pressure or an atmospheric pressure is introduced thereinto to cause the valve body to be vertically moved and thereby enable the opening to be occluded or opened.
When the valve body moves away from the partitioner to cause the opening to be opened, the inner orifice is put in an operating state, so that a vibration damping operation in a frequency range set with respect to the inner orifice is carried out effectively with a liquid flow in the outer orifice suppressed.
Meanwhile, because the projection of the valve body is inserted in the opening, the occurrence of loosening of the occlusion due to a lateral deviation of the first diaphragm is prevented, so that the first diaphragm can tightly abuts at all times on the partitioner without being laterally displaced with respect to the latter. Accordingly, a sufficient occluded condition can be secured, whereby stable characteristics of the apparatus can be maintained for a long period.
The circumferentially extending outer orifice may extends along a circular, elliptic or polygonal shape, or some other complete annular shape; or a shape of a part of any of these shapes.
In this vibration isolating mount, the outer orifice may be formed as a shaking vibration damping member, and the inner orifice as an idling vibration damping member.
A flow passage of the outer orifice is formed to a length larger than that of a flow passage of the inner orifice, and/or a cross-sectional area in the axial direction of the vibration isolat
Takaoka Masashi
Takashima Yukio
Dickson Paul N.
Jordan and Hamburg LLP
King Bradley
Toyo Tire & Rubber Co., Ltd.
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