Spring devices – Resilient shock or vibration absorber – Including energy absorbing means or feature
Reexamination Certificate
2001-08-09
2002-10-01
Schwartz, Christopher P. (Department: 3683)
Spring devices
Resilient shock or vibration absorber
Including energy absorbing means or feature
Reexamination Certificate
active
06457703
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an engine mount used for supporting an automobile engine and the like on a vehicle body.
In general, when an automobile engine and the like is installed on a vehicle body, engine mounts are interposed therebetween in order to control vibration transmission from an engine to a vehicle body. One prior art example of an engine mount is shown in FIG.
3
. The engine mount comprises a body side metal fitting
101
fixed to a vehicle body, an engine side metal fitting
102
fixed to an engine, a vibration isolating base body
103
formed of a rubber elastic body interposed between both of the metal fittings
101
and
102
, and a liquid chamber
107
partitioned into a main chamber
105
and an auxiliary chamber
106
by a partition member
104
, whereby the vibration damping function and the vibration isolating function are achieved by the operation of the vibration isolating base body
103
and a liquid flow effect through an orifice
108
provided at the partition member.
Further, a stopper mechanism
109
is provided in order to prevent a large displacement of the engine mount caused by vibration of an engine and the like. Namely, an outer peripheral flange
110
of the engine side metal fitting
102
is covered by a coating rubber layer
111
so as to form a stopper rubber portion
112
. The cylindrical body side metal fitting
101
is provided with a cylindrical portion
113
extending to the engine side so as to oppose the stopper rubber portion
112
and with an inner peripheral flange
114
formed radially inwardly from the cylindrical portion
113
. By maintaining a given clearance between both of the above mentioned cylindrical portion
113
and the inner peripheral flange
114
and the stopper rubber portion
112
, an excessive displacement of the engine mount, which occurs for example during the vehicle running on a bad road, is absorbed.
In the above stopper mechanism, however, the coating rubber layer of the stopper rubber portion is made of a comparatively soft rubber elastic composition. Accordingly, in case where continuously repeated vibration is exerted on the stopper mechanism during the vehicle running on a bad road for a long period, the stress is likely to concentrate on a boundary portion between the soft coating rubber layer and the outer peripheral flange covered thereby, which results in the occurrence of cracks of the coating rubber layer.
In order to solve the above problem, it may be proposed to enhance the rigidity of the coating rubber layer by increasing a spring constant of the coating rubber layer. However, in view of the fact that the coating rubber layer is formed integrally with the vibration isolating base body, such solution affects the spring constant of the vibration isolating base body, namely, the properties of the engine mount. Alternatively, a different component having a high rigidity may be applied in place of the coating rubber layer. However, such alternate component leads to increasing of material costs and production costs.
SUMMARY OF THE INVENTION
In view of the above, it is an object of the present invention to provide an engine mount wherein the durability of the stopper rubber portion is improved without affecting the spring properties of the vibration isolating base body.
It is another object of the present invention to provide an engine mount having a low-cost stopper rubber portion having high durability.
The inventors have made various studies with respect to an engine mount which can improve durability of the stopper rubber portion without affecting the spring properties of the vibration isolating base body and as a result, it has been found that a low-cost stopper rubber portion having a high rigidity can be obtained without affecting the spring properties of the vibration isolating base body provided that a reinforcing metal fitting is embedded in the coating rubber layer to enhance the rigidity thereof.
According to the present invention, a stopper mechanism which absorbs an excessive displacement of an engine mount comprises a cylindrical metal fitting provided at a body side metal fitting surrounding a engine side metal fitting and a stopper rubber portion protruding from the engine side metal fitting so as to oppose to said cylindrical metal fitting. The stopper rubber portion is comprised of an outer peripheral flange protruding radially outwardly from the engine side metal fitting, a coating rubber layer covering said outer peripheral flange, and a reinforcing metal fitting embedded in said coating rubber layer.
Namely, the present invention provides an engine mount having a vibration isolating base body formed of a rubber elastic body interposed between a body side metal fitting and an engine side metal fitting. The body side metal fitting is provided with a cylindrical metal fitting surrounding an engine side metal fitting. The engine side metal fitting is provided with a stopper rubber portion opposed to the cylindrical metal fitting. The stopper rubber portion comprises an outer peripheral flange protruding radially outwardly from the engine side metal fitting, a coating rubber layer covering the outer peripheral flange and a reinforcing metal fitting embedded in the coating rubber layer.
Such reinforcing metal fitting may be embedded in the coating rubber layer in an integral molding process of the coating rubber layer and the vibration isolating base body without taking a separate molding process, and so the production costs bear comparison with the case of manufacturing an engine mount having no such reinforcing metal fitting. The material cost of the reinforcing metal fitting is cheaper as compared with a different component having a high rigidity to be applied in place of the coating rubber layer.
The reinforcing metal fitting may be embedded in any position of the coating rubber layer in order to increase the rigidity of the coating rubber layer. For example, the reinforcing metal fitting may be embedded at a position where vibration is repeatedly received, that is, a position opposed to an inner peripheral face of the cylindrical metal fitting or a position opposed to an inner peripheral flange formed radially inwardly from the cylindrical metal fitting. Preferably, the reinforcing metal fitting is embedded in both of the above mentioned positions, namely, the position opposed to an inner peripheral face of the cylindrical metal fitting and the position opposed to an inner peripheral flange.
Accordingly, the present invention also provides an engine mount comprising a body side metal fitting, an engine side metal fitting and a vibration absorbing base body formed of a rubber elastic body interposed therebetween, a cylindrical metal fitting provided at the body side metal fitting surrounding the engine side metal fitting, an inner peripheral flange extending radially inwardly from the cylindrical metal fitting, a stopper rubber portion protruding from the engine side metal fitting opposed to both the cylindrical metal fitting and the inner peripheral flange, the stopper rubber portion comprises an outer peripheral flange extending radially outwardly from the engine side metal fitting, a coating rubber layer covering the outer peripheral flange and a reinforcing metal fitting embedded in the coating rubber layer, the reinforcing metal fitting being embedded in both a position opposed to the inner peripheral face of the cylindrical metal fitting and a position opposed to the inner peripheral flange respectively.
The reinforcing metal fittings embedded in both positions may be formed as a single unit. Namely, a reinforcing metal fitting may be formed in a L-shape cross section having a radial reinforcing portion opposed to the inner peripheral face of the cylindrical metal fitting and an axial reinforcing portion opposed to the inner peripheral flange. Such reinforcing metal fitting is easily embedded, during a vulcanization-molding process of the coating rubber layer, the comer portion of the L-shape reinforcing metal fitting prevents stress con
Inada Tsuyoshi
Kato Hironori
Yamamoto Kentaro
Schwartz Christopher P.
Toyo Tire & Rubber Co., Ltd.
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