Spring devices – Resilient shock or vibration absorber – Including energy absorbing means or feature
Reexamination Certificate
2000-12-21
2003-07-15
Graham, Matthew C. (Department: 3683)
Spring devices
Resilient shock or vibration absorber
Including energy absorbing means or feature
C267S140140
Reexamination Certificate
active
06592110
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a Switchable Liquid-filled Vibration Absorbing Mount to be used for supporting a power unit of an automobile or another vibrating body in a vibration preventing manner.
In the prior art, the liquid-filled vibration absorbing mount has been used as a mount for bearing the vibrating body such as an automotive engine in a manner to transmit of vibration to the vehicular body.
As this liquid-filled vibration absorbing mount, there has been proposed (Japanese Patent Laid-Open or Unexamined Publication Nos. JP-A-1996-270718, JP-A-1998-238586 or JP-A-1998-184777, for example) which is switched for the vibration absorbing characteristics in accordance with two kinds of vibrations of different frequency ranges such as the shaking vibrations or the idle vibrations.
The switchable liquid-filled vibration absorbing mount of the prior art, as disclosed in Unexamined Published Japanese Patent Application No. JP-A-1996-270718, has the following construction, as shown in FIG.
6
.
This vibration absorbing device is constructed to comprise: a first rigid mounting fixture (
101
); a second rigid mounting fixture (
102
) formed into a bottomed cylindrical shape having a bottom portion positioned at a predetermined distance in the axial direction from the first mounting fixture (
101
); a vibration absorbing base (
103
) made of a rubbery elastomer and interposed between the first mounting fixture (
101
) and the second mounting fixture (
102
) for jointing the two mounting fixtures (
101
) and (
102
); a partition member (
104
), a first diaphragm (
105
) and a second diaphragm (
106
) arranged in series in the axial direction between the vibration absorbing base (
103
) and the second mounting fixture (
102
); a main liquid chamber (
107
) formed between the vibration absorbing base (
103
) and the partition member (
104
); an auxiliary liquid chamber (
108
) formed between the partition member (
104
) and the first diaphragm (
105
); an outer orifice (
113
) and an inner orifice (
114
) disposed in the partition member (
104
) for providing a communication between the main liquid chamber (
107
) and the auxiliary liquid chamber (
108
), the outer orifice (
113
) being extended over a predetermined length in the circumferential direction of the partition member (
104
), the inner orifice (
114
) being disposed on the inner side of the outer orifice (
113
) in the diametrical direction and opened/closed by the first diaphragm (
105
); bias means (
127
) for pushing the first diaphragm (
105
) toward the partition member (
104
) so as to block the flow of the liquid between the inner orifice (
114
) and the auxiliary liquid chamber (
108
); a balance chamber (
109
) formed between the first diaphragm (
105
) and the second diaphragm (
106
); and a change-over chamber (
110
) formed between the second diaphragm (
106
) and the second mounting fixture (
102
) and capable of having the atmospheric pressure and a vacuum introduced selectively thereinto. When the vacuum is introduced into the change-over chamber (
110
), the first diaphragm (
105
) is moved against the biasing force of the bias means (
127
) to leave the partition member (
104
) thereby to provide the communication between the inner orifice (
114
) and the auxiliary liquid chamber (
108
). By switching the introductions of the atmospheric pressure and the vacuum into the change-over chamber (
110
) selectively, the inner orifice (
114
) can be opened/closed so that the orifices individually coping with the two kinds of vibrations in different frequency ranges can be selectively employed.
In this liquid-filled vibration absorbing mount of the prior art, not only the outer orifice (
113
) but also the inner orifice (
114
) to be opened/closed by the first diaphragm (
105
) is ring-shaped. Therefore, the inner orifice (
114
) has a certain length to extend in the circumferential direction so that a liquid to flow in the inner orifice (
114
) is subjected to a flow resistance. As a result, the liquid becomes hard to flow in the inner orifice (
114
). Thus, the liquid flows in the outer orifice (
113
) so that a sufficient vibration attenuating effect cannot be obtained in the inner orifice (
114
).
In order to close the inner orifice (
114
), on the other hand, the first diaphragm (
105
) is pushed at its central portion to the lower face of the partition member (
104
) through a push member (
162
) by the bias means (
127
). Specifically, the flat central portion of the first diaphragm (
105
) comes into abutment against the flat portion of the circumference of an opening (
114
a
) of the inner orifice (
114
) on the side of the auxiliary liquid chamber (
108
) in the partition member (
104
) so that the inner orifice (
114
) is closed exclusively by such planar abutment. When a high pressure is abruptly built up in the main liquid chamber (
107
), for example, or when the first diaphragm (
105
) is transversely displaced or deformed by the rocking motions or the like to slacken the abutting portion slightly, therefore, the inner orifice (
114
) may not be sufficiently closed so that the stable vibration absorbing characteristics cannot be obtained.
SUMMARY OF THE INVENTION
The invention has been conceived in view of the description thus far made and contemplates to improve the aforementioned conventional liquid-filled vibration absorbing mount, in which the inner one of the two inner and outer orifices can be opened/closed to allow the orifices individually coping with the two vibrations of different frequency ranges such as the shaking vibrations and the idle vibrations to be selectively employed, especially the shape of the inner orifice and the shape of the first diaphragm for closing the inner orifice, thereby to solve the aforementioned problems, to exhibit the vibration attenuations effectively in the different frequency ranges and to hold the stable characteristics.
As in the aforementioned liquid-filled vibration absorbing mount, according to the invention, there is provided a switchable liquid-filled vibration absorbing mount comprising: a first mounting fixture; a second mounting fixture formed into a bottomed cylindrical shape; a vibration absorbing base jointing the two mounting fixtures; a partition member, a first diaphragm and a second diaphragm arranged in series between the second mounting fixture and the vibration absorbing base; a main liquid chamber and an auxiliary liquid chamber partitioned by the partition member; two outer and inner orifices and an inner diaphragm disposed for providing a communication between the two chambers; bias means for pushing the first diaphragm toward the partition member; a balance chamber formed between the first diaphragm and the second diaphragm; and a switching chamber formed between the second diaphragm and the second mounting fixture, wherein the improvement resides: in that the inner orifice is an opening extending in the axial direction through the partition member; in that the first diaphragm is provided at its central portion with a valve member for closing the inner orifice, the valve member including: a flat rubber face confronting the lower face of the circumference of the inner orifice in the partition member when the atmospheric pressure is introduced into the change-over chamber, and a protrusion protruding from the flat rubber face and fitted in the inner orifice; and in that by selecting the introduction of either the atmospheric pressure or the vacuum into the switching chamber, the valve member is moved up and down to open/close the opening, and the transverse displacement of the valve member is regulated by the protrusion.
According to this switchable liquid-filled vibration absorbing mount, when the atmospheric pressure is introduced into the switching chamber, the flat rubber face of the valve member belonging to the first diaphragm is biased by the bias means to confront the lower face of the circumference of the inner orifice thereby to hold the inner orifice in the closed state so that the vibration
Kodama Yosei
Kuze Kazumasa
Takaoka Masashi
Takashima Yukio
Yoshida Nobuya
Burch Melody M.
Graham Matthew C.
Jordan and Hamburg LLP
Toyo Tire & Rubber Co., Ltd.
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