Spring devices – Resilient shock or vibration absorber – Including energy absorbing means or feature
Reexamination Certificate
1999-06-11
2002-06-04
Rodriguez, Pam (Department: 3613)
Spring devices
Resilient shock or vibration absorber
Including energy absorbing means or feature
C267S141700
Reexamination Certificate
active
06398200
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a vibration isolating mount having a toe correcting mechanism used in suspension or the like of a vehicle.
Conventionally, a vibration isolating mount having a toe correcting mechanism of this kind has been used in, for example, a rear suspension of an automobile.
FIG. 8
is a plane view showing a rear suspension of an automobile in which both left and right side of suspension arms
100
are connected to a torsion beam
101
, wheels
104
are attached to outer end sides of wheel shafts
103
and vibration isolating mounts
105
, attached to connection cylinders at front ends of the arms
100
, are connected to vehicle side brackets
106
by bolts and nuts.
FIG. 9
shows a sectional view of the conventional vibration isolating mount
105
. The left or right vibration isolating mount
105
is provided with a shaft member, such as an inner cylinder
108
, through a center hole
108
a
of which a bolt is penetrated, an outer cylinder
109
, a rubber-like elastic body
110
interposed between the inner cylinder
108
and the outer cylinder
109
, and a toe correcting mechanism
111
formed at one end portion of the vibration isolating mount
105
.
According to the toe correcting mechanism
111
, an inclined plate
112
is welded to one outer side of one end portion of the inner cylinder
108
, a taper portion
113
is formed to expand at an end portion of the outer cylinder
109
opposite to the inclined plate
112
and a rubber-like elastic body
110
a
is interposed between the taper portion
113
and the inclined plate
112
, by which thrust force which is force in the axial direction (length direction of inner cylinder) inputted from the suspension arm
100
by cornering force or the like, is dispersed in the direction orthogonal to the axial direction and operates a moment for leading the suspension arm
100
to the toe-in side.
In order to achieve compliance steering by the toe correcting mechanism
111
a spring constant of the rubber-like elastic body
110
must be restrained low, however, by setting the low spring constant, displacement of the rubber-like elastic body
110
in the axial direction is increased and durability of rubber is deteriorated. Therefore, in order to promote the durability of rubber by restraining the displacement of the rubber-like elastic body
110
, the vibration isolating mount
105
is installed with a stopper
115
for restraining the displacement of the outer cylinder
109
in the axial direction to a predetermined amount against input of thrust in the axial direction.
The stopper
115
is constituted by a stopper metal piece
117
in a plate-like shape which is welded to an end portion of the inner cylinder
108
, a reinforcement metal piece
118
which is welded to the inner cylinder
108
in parallel therewith. A stopper rubber
119
covers the stopper metal piece
117
and the reinforcement metal piece
118
. A predetermined amount of a gap
122
is maintained between the stopper rubber
119
and an end flange
121
of the outer cylinder
109
.
Further, there is adopted a constitution in the rubber-like elastic body
110
in which bored portions
120
at least one end of each of which are opened and which are holes or gaps extending in the axial direction are formed at a plurality of locations of the surrounding of the inner cylinder
108
, by which spring constant in a direction orthogonal to the axial direction is lowered and ride quality is promoted.
Such a conventional vibration isolating mount
105
has difficulties such as the cost is high, a structure of a rubber vulcanizing mold is complicated and product weight is heavy. That is, according to the conventional vibration isolating mount
105
, in order to promote durability of the rubber-like elastic body
110
having the low spring constant for achieving compliance characteristic, the stopper
115
is installed at end portion of the inner cylinder
108
with a gap
122
between the stopper
115
and the end portion
121
of the outer cylinder
109
and, the bored portions
120
are formed in the rubber-like elastic body
110
in the axial direction to lower the spring constant of the vehicle in the forward and rearward direction (direction orthogonal to axial direction) and to promote ride quality.
A direction of opening the gap
122
and a direction of opening the bored portion
120
are different from each other. Thus, a core die for forming the bored portions and a core die for forming the gap of the stopper are needed in the rubber vulcanizing mold in fabricating the vibration isolating mount since directions of drawing the core dies after molding are different from each other. Accordingly, there are difficulties in which fabrication of a product is complicated and the cost is high.
Furthermore, when the bored portion
120
are formed deeply to make the spring constant in the axial direction as uniform as possible, a thin film
123
is formed between a bottom portion
120
a
of the bored portion
120
and the gap
122
of the stopper
115
. According to the thin film structure, when load resulting in large displacement is applied, the thin film
123
is often broken a constitutes a start point of crack, rupture and crack is propagated to a main body side of the rubber-like elastic body
110
to thereby cause deterioration in the durability of the vibration isolating mount
105
.
Further, strength is needed in the stopper metal piece
117
against input of large load in the left and right direction (axial direction) of the vehicle. The reinforcement metal piece
118
needs to be installed separately from the stopper metal piece
117
or a plate thickness of the stopper metal piece
117
needs to increase, thereby causing a difficulty in which the weight of the vibration isolating mount is increased. Further, the stopper metal piece
117
and the reinforcement metal piece
118
must be welded to the outer peripheral face of the inner cylinder
108
and accordingly, the fabrication cost is increased.
SUMMARY
Hence, it is a first object of the present invention to provide a vibration isolating mount achieving light-weighted formation by abolishing a stopper metal piece and a reinforcement metal piece on a side of an inner cylinder by changing a shape of an outer cylinder, achieving reduction in fabrication cost by simplifying structure of a mold die in vulcanizing rubber and which is excellent in durability.
In the meantime, according to the vibration isolating mount having the toe correcting mechanism mentioned above, in order to apply preliminary compression on the rubber-like elastic body
110
interposed between the inner cylinder
108
and the outer cylinder
109
, as shown by
FIG. 10
, diameter reducing process is carried out on the outer cylinder
109
. In that case, the preliminary compression is difficult to apply, to the rubber-like elastic body
110
a
interposed between the inclined plate
112
and the taper portion
113
which are opposed to each other, since the inner cylinder
108
is moved in a direction designated by an arrow mark P by reaction force of rubber when the outer cylinder
109
is compressed in the radius direction. Tensile force is exerted on an outer peripheral portion
110
b
of the rubber-like elastic body
110
by moving the inner cylinder
108
and distortion caused by the tensile force deteriorates durability of the rubber-like elastic body
110
. Meanwhile, according to such a conventional vibration isolating mount, as shown by
FIG. 10
, a restraining member
125
for restraining displacement of the inner cylinder
108
in a direction orthogonal to the axial direction may be attached press-fit to the inner cylinder
108
.
Hence, it is a second object of the present invention to alleviate distortion of a rubber-like elastic body at diameter reducing process by utilizing a restraining member for restraining displacement of an inner cylinder and finding a novel constitution at its surrounding portion to thereby fabricate a vibration isolating mount having the restraining member at a l
Horikoshi Kazuhiro
Kakimoto Toshihiro
Kato Yoshihisa
Kawada Michihiro
Kobayashi Hideyuki
Jordan and Hamburg LLP
Rodriguez Pam
Toyo Tire & Rubber Co., Ltd.
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