Spring devices – Resilient shock or vibration absorber – Including energy absorbing means or feature
Reexamination Certificate
1998-12-17
2001-01-09
Oberleitner, Robert J. (Department: 3613)
Spring devices
Resilient shock or vibration absorber
Including energy absorbing means or feature
Reexamination Certificate
active
06170811
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 vehicle.
The conventional liquid filled vibration isolator of this type has, as shown in
FIG. 8
, for example a rubber member
2
coupled on the upper end side of a cylindrical member
1
, and the rubber member
2
is provided with a fitting member
3
fixed coaxially to the cylindrical member
1
. The cylindrical member
1
has a thin rubber member coated part
4
disposed continuous to the rubber member
2
on the inner peripheral surface thereof, and has an orifice member
5
and a diaphragm member
6
disposed on inner peripheral portion of the lower end side thereof from inside sequentially in the axial direction. The orifice member
5
and the diaphragm member
6
thus close the lower end side opening portion of the cylindrical member
1
, and tight seal a liquid chamber E provided between them and the rubber member
2
. In addition, by drawing the lower end side of the cylindrical member
1
(diameter-reducing processing) thereof, the orifice member
5
and the diaphragm member
6
are fixed to the cylindrical member
1
.
Meanwhile, in the above-stated liquid filled vibration isolator, the orifice member
5
and the diaphragm member
6
are fixed to the cylindrical member
1
only by the reactive force of the rubber member coated part
4
resulting from the drawing of the cylindrical member
1
. Due to this, there is a fear that the diaphragm member
6
and the like slip out of the cylindrical member
1
as a result of, for example, the fatigue of the rubber member coated part
4
if the vibration isolator are used for a long period of time.
SUMMARY OF THE INVENTION
The present invention has been made to solve the above problem. It is therefore an object of the present invention to provide a liquid filled vibration isolator capable of ensuring that the diaphragm member and the orifice member are prevented from undesirably slipping out of the cylindrical member.
A liquid filled vibration isolator according to the present invention comprises a cylindrical member made of a metal material; an inward-bent part slightly extending to one end side of the cylindrical member inwardly in a radial direction; a thin rubber member coated part provided on an inner peripheral surface of the cylindrical member, the rubber member coated part having an inner diameter equal to or smaller than an inner diameter of the inward-bent part; a bottom wall member inserted into the rubber member coated part on the one end side of the cylindrical member to close thereby an opening portion on the one end side thereof; a rubber member subjected to vulcanization and bonding and a fitting member fixed to the rubber member provided on the other end side of the cylindrical member to close thereby an opening portion on the other end side thereof; and a liquid chamber for vibration isolation thereby formed inside the cylindrical member, and is characterized in that the inner diameter of the inward-bent part is made smaller than an outer diameter of the bottom wall member by conducting drawing to the cylindrical member. An diaphragm member, an orifice member and the like are used as the bottom wall member.
With the above-stated structure of the present invention, if one end side of the cylindrical member is subjected to drawing and the diameter of the inward-bent part, which has been provided on one end portion of the cylindrical member in advance, is reduced, then the inner diameter of the inward-bent part is smaller than the outer diameter of the bottom wall member. Due to this, the outer peripheral portion of the bottom wall member is stopped by the inward-bent part. As a result, the present invention can ensure that the bottom wall member is prevented from slipping out of the cylindrical member even if the fastening force is lowered by, for example, the fatigue of the rubber member coated part.
The inward-bent part may be formed by conducting blanking to a collar-shaped inner bottom wall part formed integral with one end side of the cylindrical member while the cylindrical member is formed by press-molding a metal plate material, the inner bottom wall part extending inwardly in an radial direction. If so, it is possible to easily form the inward-bent part at low cost.
A cylindrically protruding part which slightly protrudes within a prescribed range from a prescribed position of the rubber member coated part in an axial direction to the other end side, along a circumferential direction and toward a radial direction, may be provided. In addition, a stepped part may be provided at a boundary between the rubber coated part and the cylindrically protruding part. This stepped part can be used for positioning of the bottom wall member, thereby enabling the easy and accurate insertion of the bottom wall member.
A liquid filled vibration isolator according to the second invention comprises a cylindrical member made of a metal material; a thin rubber member coated part provided on an inner peripheral surface of the cylindrical member; a bottom wall member inserted into the rubber member coated part on one end side of the cylindrical member to close thereby an opening portion on the one end side thereof; a rubber member subjected to vulcanization and bonding and a fitting member fixed to the rubber member provided on the other end side of the cylindrical member to close thereby an opening on the other end side thereof; and a liquid chamber for vibration isolation thereby formed inside the cylindrical member, and is characterized in that an diameter of the one end side of the cylindrical member is reduced by drawing and the one end portion of the cylindrical member is bent inwardly in a radial direction by bending, thereby forming an inward-bent part having an inner diameter of the one end portion almost equal to an outer diameter of the bottom wall member; one end side of the rubber member coated part is compressed and an end portion of the one end side thereof is expanded between the inner-bent part and the bottom wall member to cover a one end-side outer peripheral portion of the bottom wall member; and an inner diameter of the expanded end portion of the rubber member coated part is smaller than the outer diameter of the bottom wall member.
With the above-stated structure of the second invention, the diameter of the one end side of the cylindrical member is reduced by drawing and the end portion of the cylindrical member is subjected to bending, thereby forming an inward-bent part having an inner diameter almost equal to the outer diameter of the bottom wall member at one end portion of the cylindrical member. Following the drawing and bending, the one end side portion of the rubber member coated part is compressed. The one end side portion is then expanded between the inward-bent part and the bottom wall member to thereby cover the one end-side outer peripheral portion of the bottom wall member. The inner diameter of the expanded portion is smaller than the outer diameter of the bottom wall member. Due to this, the outer peripheral portion of the bottom wall member is stopped by the tip end portion of the rubber member coated part. As a result, according to the second invention, even if the fastening force is lowered by, for example, the fatigue of the rubber member coated part, it is ensured that the bottom wall member is prevented from slipping out of the cylindrical member.
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Suzuki Shingo
Yotani Yorishige
Kramer Devon
Oberleitner Robert J.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Tokai Rubber Industries Ltd.
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