Note: Descriptions are shown in the official language in which they were submitted.
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RUBBER/METAL BEARING FOR COUPLING A STABILIZER
BAR TO AN AUTOMOTIVE BODY
Description
The invention relates to a rubber/metal bearing
for coupling a stabilizer bar to an automotive body,
having a rubber body which surrounds the stabilizer bar
and having a sleeve which can be attached to the
automotive body for the purpose of accommodating the
rubber body and the stabilizer bar which is guided
therein. In the context of the invention, automotive body
encompasses in particular the entire body structure,
including underbody and floor pan.
A rubber/metal bearing of this type is known in
practice. It is regularly used to guide and hold or couple
the stabilizer bar to a floor pan of the automotive body.
A stabilizer bar is known to be a so-called bar spring,
usually made from rod steel bent into the shape of a U, in
order to strengthen the suspension during compression and
rebounding on one side. For this purpose, stabilizer bars
connect the two wheels of an axle to reduce the
inclination of the automotive body, for example when
~raveling round a bend, since the compressed wheel in each
case causes torsion of the stabilizer bar and
corresponding restoring forces which counteract
inclination of the automotive body. Consequently, when the
spring travels of the two wheels of an axle are equal the
stabilizer bar remains inactive. At any rate, it is
necessary that such rubber/metal bearings absorb, in
particular, rotational movements of the stabilizer bar
caused by torsion in order to couple and hold a stabilizer
bar on an automotive body.
According to the prior art, two different lines of
development are in principle being pursued in order to
realize rubber/metal bearings of this nature. In the first
of these, the rubber body and the sleeve are separate
parts which are only combined during installation. On the
one hand, this entails installation problems, and on the
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other hand it means that it is necessary to accept that
the stabilizer bar will slip through the rubber body. To
this end, low friction coatings, for example, TeflonTM
coatings, which reduce the coefficient of friction are
inserted between rubber body and stabilizer bar. As a
result, not only is the installation and manufacturing
cost increased, but also there is the risk in particular
that the known bearings will emit squeaking noises when
traveling around bends. This adverse effect is
particularly noticeable during temperature fluctuations
(summer and winter operation), with the associated change
in elasticity of the rubber body (soft-hard). Moisture,
salt and similar environmental influences also have an
adverse effect on the noise emitted by the known
rubber/metal bearings.
The second of these known developments involves
vulcanizing the rubber body directly on to the stabilizer
bar. Although in this embodiment rotational movements of
the stabilizer bar are directly absorbed in the rubber
body, production is extremely expensive, since small
rubber bodies have to be vulcanized on to the protruding
stabilizer bars. Moreover, wear to the known rubber/metal
bearings entails the replacement of the entire stabilizer
bar with the molded-on rubber body. In addition, the
position of the rubber body with respect to the stabilizer
bar cannot be made flexible, owing to the fixed
connection.
Independently of the above, German patent
28 38 391 has disclosed a rubber/metal bearing for
supporting a wheel control link, which bearing has an
elastic rubber body which is arranged between an outer and
an inner metal sleeve and is vulcanized on to said
sleeves. In this case, in order to achieve a radial
displacement of the two metal sleeves, the lateral
surfaces, which face the rubber body, of the inner and
outer metal sleeves are designed so as to run at least
partially at an angle to the axis of the rubber/metal
-
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bearing.
Furthermore, German patent 40 06 922 has disclosed
a rear axle bearing for a twist-beam rear axle for motor
vehicles which has a rubber/metal sleeve comprising a
metal inner sleeve, a metal outer sleeve and a hollow
rubber body which is vulcanized in between inner sleeve
and outer sleeve. This rear axle bearing has per se proven
itself, but does not contribute further to solving the
problems listed at the outset.
The invention is based on the object of providing
a rubber/metal bearing of the general type described above
which is more simply and economically produced and is easy
to install, and which in particular works without emitting
high levels of noise.
To achieve this object, the invention proposes, in
the case of a rubber/metal bearing of the generic type for
coupling a stabilizer bar to an automotive body, that the
rubber body essentially comprises a stop member which is
fastened in the sleeve and a closure member which is
pivotably connected to the sleeve, it being possible, with
the closure member pivoted down, for the stabilizer bar to
be introduced into the sleeve and placed against the stop
member, and it being possible to connect the stabilizer
bar in a rotationally fixed manner to the rubber body by
frictional engagement by means of the closure member,
which can be pivoted up during installation, so as to
produce stressing of the rubber body. As a result, in
particular squeaking or noise generation by the
rubber/metal bearing is avoided, specifically as a result
of the rotationally fixed connection between, on the one
hand, rubber body and, on the other hand, stabilizer bar,
while simultaneously ensuring simple installation and
manufacturing. According to a preferred embodiment, the
stop member is vulcanized into the sleeve. The closure
member may be pivotably connected to the sleeve by means
of an integral rubber hinge which is vulcanized on to the
sleeve and the closure member. According to a preferred
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embodiment, which is assigned independent importance, it
is provided for the closure member to have a body stop
which, on the vehicle side, is vulcanized on and, when the
rubber/metal bearing has been installed, bears against the
automotive body. Furthermore, in a further, particularly
preferred embodiment, it is provided for the stop member
and the closure member to each be designed as rubber half
shells, on the one hand as a closure half shell and on the
other hand as a stop half shell, the stop half shell
having, above the integral rubber hinge, a drawn-down lug
so as to form a recess for a web of the closure half
shell, which web engages in this recess in the manner of a
hinge during installation of the rubber/metal bearing.
Moreover, the rubber body which, in the installed
position, is connected by frictional engagement to the
stabilizer bar, may be of resilient design and, by means
of intramolecular spring forces, is able to absorb torsion
angles of the stabilizer bar which lie in the range from
approximately 10~to 60~ preferably 15~to 35~
Generally, the sleeve is designed as a metal strip
made from an aluminum alloy, the cross section of the
metal strip approximating to the shape of an omega (Q)with
a sleeve eyelet for accommodating the rubber body and
attachment limbs on both sides. The body stop which is
vulcanized on to the closure member is generally also made
from an aluminum alloy. The sleeve eyelet mainly has, on
the inside, a latching lug which faces toward the closure
member, lies opposite the integral hinge and over which,
for the purpose of prefitting the rubber/metal bearing on
the stabilizer bar, an edge of the closure member passes
with a latching action. One attachment limb of the sleeve
is regularly designed as a lug limb which engages beneath
a cutout in the vehicle body and the other attachment limb
is designed as a screw-on limb which can be connected to
the vehicle body. Furthermore, it is preferably provided
for the lug limb and the screw-on limb to extend
essentially in planes which are parallel to one another
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.
and spaced apart from one another, the distance between
the planes generally depending on the thickness of a
vehicle body floor pan beneath which the lug limb engages
and on the stressing of the rubber body which can be
prescribed during installation, the top side of the lug
limb bearing against an inner surface of the floor pan and
the underside of the screw-on limb bearing against an
outer surface of the floor pan. Consequently, it is
possible, inter alia by means of the distance between the
planes, to adjust the stressing of the rubber body.
However, the distance between the above-mentioned planes
generally corresponds to the thickness of the floor pan
beneath which the lug limb engages, in which case the
underside of the closure member projecting beyond the
underside of the screw-on limb by a specific dimension
which determines the level of stressing of the rubber
body.
These inventive measures firstly provide a
rubber/metal bearing which is simple and economical to
produce for coupling a stabilizer bar to an automotive
body, because production is limited to fastening or
vulcanizing the stop body or the stop half shell in the
sleeve and attaching or vulcanizing the closure member to
the sleeve. This is achieved by means of the integral
rubber hinge, which as a rule connects the body stop to
the sleeve. This means that stop body or stop half shell
and sleeve or sleeve eyelet, and also body stop and
closure member or closure half shell can in each case be
produced in an upstream step, for example by sheet metal
forming (deep drawing) and vulcanization. Then, the
closure body together with the body stop which, on the
vehicle side, is vulcanized on can be connected to the
sleeve via the integral rubber hinge. The sleeve as such
can also be produced easily and without problems from a
metal strip (deep drawn and, if appropriate, provided with
holes) made from an aluminum alloy. At the same time, a
product which is overall inexpensive is provided.
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.
Moreover, installation is simplified and
associated with cost benefits if the rubber/metal bearing
according to the invention is overall a one-part
structure. It is no longer necessary to join together
various components, as is required according to the prior
art. Moreover, it is possible to do away with the
expensive and time-consuming process of vulcanizing the
rubber body on to the stabilizer bar. As a result of the
latching lug which is provided according to a preferred
embodiment, it is possible, furthermore, to connect one or
more rubber/metal bearings according to the invention to a
stabilizer bar during prefitting. This means that the
rubber/metal bearings which have been prefitted in such a
way can be supplied for final installation as a prefitted
assembly complete with the stabilizer bar. Moreover, this
final installation is facilitated if the stabilizer bar is
fixed in the rubber/metal bearing while the sleeve is
being attached to the automotive body, and consequently
cannot rock back and forth. Consequently, at the same time
potential risks of injury during final installation are
avoided.
Moreover, it is particularly important for
rotational movements of the stabilizer bar to be absorbed,
in particular regularly, as a result of intramolecular
spring forces in the rubber body, in that torsion angles
of the stabilizer bar through the range from approximately
10~to 60~ preferably 15~to 35~, lead to a corresponding
torsion of the rubber body. This means that slipping of
the stabilizer bar in the rubber body - as always occurs
in the prior art - is deliberately avoided. Consequently,
squeaking noises are reliably prevented, precisely because
of the fact that there is frictional engagement between
rubber body and stabilizer bar, and accordingly the rubber
body follows torsional movements of the stabilizer bar. In
this case, the invention is based on the recognition that
in the present case, as a rule, coefficients of friction
of approx. 0.5 (rubber on metal) can be reached, which
. .., . ~ .
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coefficients, owing to the stressing of the rubber body,
lead to a perfect connection between the stabilizer bar
and the rubber body with frictional engagement.
Consequently - in contrast to the prior art - high
coefficients of friction can be deliberately set, in order
knowingly to bring about torsion of the rubber body.
In the prior art, such torsional movements of the
rubber body have hitherto only been achievable by
vulcanizing this rubber body directly on to the stabilizer
bar in a complicated and expensive manufacturing step. In
contrast to this, the invention not only provides a
rubber/metal bearing which is simple and inexpensive to
produce, but also, in addition, in particular installation
is considerably simplified. This also applies with regard
to the flexibility of positioning of the rubber/metal
bearing with respect to the stabilizer bar which is
achieved by means of the invention. These represent the
essential advantages.
Further features which are essential to the
invention are listed below. Thus, as a rule, the rubber
body is made from a rubber-based or polymer-based
elastomer. This elastomer is preferably natural rubber
(NR) which has an application temperature range of approx.
-50~C to +90~C, a Shore A hardness of approx. 20 to 100,
preferably 60, an elongation at break of 100~ to 800~,
preferably more than 400~, and a density of approximately
1.2 g/cm3. Finally, the rubber body may have, on the
stabilizer bar side, one or more bearing shells with or
without a vulcanized-on rubber coating. Naturally, the
bearing shells may be vulcanized on to or into the rubber
body.
The invention is explained in more detail below
with reference to a drawing, which illustrates only one
exemplary embodiment. In the drawing:
~ig. 1 shows a vehicle axle having the essential
components, including stabilizer bar,
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.
Fig. 2a shows the rubber/metal bearing according to the
invention in the pivoted-open position,
Fig. 2b shows the bearing in accordance with Fig. 2a in
the installed position, and
Fig. 3 shows a view, partially in section, of the
bearing in accordance with Fig. 2a and 2b.
The figures illustrate a rubber/metal bearing 1
for coupling a stabilizer bar 2 to an automotive body (not
shown). According to Fig. 1, the stabilizer bar 2 connects
the two wheels 3 of an axle of a motor vehicle and leads
to reinforcement of the suspension during compression and
rebounding of the wheels 3 on one side. Consequently, when
traveling around a bend, the stabilizer bar 2 counteracts
the inclination of the automotive body (not shown). In
Fig. 2b, all that is diagrammatically shown of the
automotive body is part of a floor pan 4. In accordance
with Fig. 2a, 2b and 3, the basic structure of the
rubber/metal bearing 1 comprises a rubber body 5 which
surrounds the stabilizer bar 2 and a sleeve 6 which can be
attached to the automotive body or to the floor pan 4, for
the purpose of accommodating the rubber body 5 and the
stabilizer bar 2 which is guided therein. The rubber body
5 essentially comprises a stop member 5a which is fastened
in the sleeve 6 and a closure member 5b which is pivotably
connected to the sleeve 6. With the closure member pivoted
down (cf. Fig. 2a), the stabilizer bar 2 can be introduced
into the sleeve 6 and placed against the stop member 5a,
it being possible to connect the stabilizer bar 2 in a
rotationally fixed manner to the rubber body 5 by
frictional engagement by means of the closure member 5b,
which can be pivoted up during installation, so as to
produce stressing of the rubber body 5. This means that in
the situation of the installed rubber/metal bearing 1
which is illustrated in Fig. 2b (solid lines), the
stabilizer bar 2 is fixedly connected to the rubber body 5
by frictional engagement, so that the rubber body 5 is
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able to resiliently absorb rotational movements of the
stabilizer bar 2 as a result of intramolecular spring
forces.
In detail, the stop member 5a is vulcanized into
the sleeve 6. The closure member 5b is pivotably connected
to the sleeve 6 by means of an integral rubber hinge 7
which is vulcanized on to the sleeve 6 and the closure
member 5b. In addition, the closure member 5b has a body
stop 8 which, on the vehicle side, is vulcanized on and,
when the rubber/metal bearing 1 has been installed, bears
against the automotive body or floor pan (4) (cf. Fig.
2b). This body stop 8, like the sleeve 6, is made from an
aluminum alloy. According to the exemplary embodiment, it
has a planar underside 9 which, when the rubber/metal
bearing 1 has been installed, bears flat against the floor
pan 4 or automotive body. The rubber body 5 which, in the
installed position (cf. Fig. 2b), is connected by
frictional engagement to the stabilizer bar 2 is of
resilient design and, by means of intramolecular spring
forces, absorbs torsion angles of the stabilizer bar 2
which lie in the range from approximately 10~ to 60~,
preferably 15~ to 35~.
This means that, in the course of its crosslinking
and as a result of the selection of material, the rubber
body 5 is designed in such a way that the above-mentioned
torsion angles can be absorbed elastically, i.e. without
damage to or tearing of the rubber body 5, with perfect
restoration. For this purpose, the rubber body 5 is made
from a rubber-based or polymer-based elastomer. According
to the exemplary embodiment, this elastomer is natural
rubber (NR) which has an application temperature range of
from approx. -50~C to +90~C, a Shore A hardness of approx.
20 to 100, preferably 60, an elongation at break of 100
to 800~, preferably more than 400~, and a density of
approximately 1.2 g/cm3. Consequently, the rubber body 5 is
predestined for use in a motor vehicle, especially since
ageing effects play only a subordinate role.
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Moreover, according to the invention it is
possible, owing to the fixed connection between stabilizer
bar 2 and rubber body 5 as a result of the frictional
engagement, to dispense with holding rings, which are
obligatory according to the prior art. Holding rings of
this nature are regularly used to prevent the stabilizer
bar 2 from moving back and forth in the longitudinal
direction inside the rubber/metal bearing 1 (cf. also the
holding rings which are merely indicated by dashed lines
in Fig. 3). According to the invention, it is possible to
do without these holding rings, or else such holding rings
can be designed in such a way that, in the context of the
invention, they merely have a sealing function.
The stop member 5a and the closure member 5b are
each designed as rubber half shells, on the one hand as a
closure half shell 5b and on the other hand as a stop half
shell 5a. Above the integral rubber hinge 7, the stop half
shell 5a has a drawn-down lug 10 so as to form a recess 11
for a web 12 of the closure half shell 5b, which web
engages in this recess in the manner of a hinge during
installation of the rubber/metal bearing 1. According to
the exemplary embodiment, the sleeve 6 is designed as a
metal strip made from an aluminum alloy, the cross section
of the metal strip approximating to the shape of an omega
(Q) with a sleeve eyelet 6a for accommodating the rubber
body 5 and attachment limbs 6b, 6c on both sides.
One attachment limb 6b, 6c is designed as a lug
limb 6b which engages beneath a cutout 13 in the vehicle
body or floor pan 4 and the other attachment limb 6b, 6c
is designed as a screw-on limb 6c which can be connected
to the vehicle body or floor pan 4. With the aid of this
screw-on limb 6c, the sleeve 6 is attached to the floor
pan 4 after the lug 6b has been introduced into the cutout
13 and has engaged beneath the floor pan 4. For this
purpose, the screw-on limb 6c has a bore for a screw (not
shown) in order to be attached to the floor pan 4.
The lug limb 6b and the screw-on limb 6c extend
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11
essentially parallel to one another, specifically in
planes A and B which are spaced apart from one another.
The distance S between these planes A and B is illustrated
in particular in Fig. 2a. According to the exemplary
embodiment, it is approx. 5 mm. This distance S between
the planes A and B depends on the thickness W of the
vehicle body floor pan 4 beneath which the lug limb 6b
engages and on the stressing ~ of the rubber body 5, which
can be prescribed during installation. This means that the
distance S is made up as follows:
S = W + ~.
According to the exemplary embodiment, ~= O, i.e.
the distance S between the planes A and B corresponds to
the thickness W of the floor pan 4 beneath which the lug
limb 6b engages. In this case, the upper side of the lug
limb 6b bears against an inner surface of the floor pan 4
and the underside of the screw-on limb 6c bears against an
outer surface of the floor pan 4. For its part, the
underside 9 of the closure member 5b or the closure half
shell 5b projects beyond the underside of the screw-on
limb 6c by a specific dimension M which determines the
level of stressing of the rubber body 5.
Depending on the magnitude of this dimension M,
the closure member or the closure half shell 5b, during
installation of the rubber/metal bearing 1, is pressed to
a greater or lesser extent on to the stop member or the
stop half shell 5a. The uninstalled position is
illustrated in dashed lines in Fig. 2b, while the
installed, stressed position of the rubber body 5 is shown
in solid lines in Fig. 2b. At any rate, it is possible in
this way to set the stressing of the rubber body 5.
Naturally, this can also be achieved by means of the
dimension ~, but this is not illustrated in the exemplary
embodiment and ultimately leads to lug limb 6b and screw-
on limb 6c, or the corresponding planes A and B, including
CA 02248823 1998-10-1
an (obtuse) angle.
Finally, on the inside the sleeve eyelet 6a has a
latching lug 14 which faces toward the closure member 5b,
lies opposite the integral hinge 7 and over which, for the
purpose of prefitting the rubber/metal bearing 1 on the
stabilizer bar 2, an edge 15 of the closure member 5b
passes with a latching action. As a result, the
illustrated rubber/metal bearing 1 according to the
invention can, as it were, be prefitted on the stabilizer
bar 2, in that the edge 15 latches over the latching lug
14. In this way, the stabilizer bar 2, together with the
prefitted rubber/metal bearings 1, of which there are
generally two, can be supplied as a finished unit for
final installation.
Overall, a particularly compact structure of the
rubber/metal bearing 1 with a relatively low rubber
content or a relatively small size of the rubber body 5 is
achieved. As a result of the frictionally locking
connection between stabilizer bar 2 and rubber body 5,
rotational movements of the stabilizer bar 2, which in any
case only move in the range up to a torsion angle of
approx. 30~, are absorbed without problems in an
intramolecular manner, i.e. by the crosslinked molecules
or molecule chains in the rubber body 5. In the end, this
is achieved by the fact that the relatively high
coefficient of friction of 0.5 (rubber on steel) is
deliberately not reduced so as to decrease the coefficient
of friction (as in the prior art), but rather ensures the
frictional engagement described above. Finally, the rubber
body 5 may, on the stabilizer bar side, have one or more
bearing shells 16 with or without a vulcanized-on rubber
coating 17. If a rubber coating 17 is not provided,
measures will be taken to increase the coefficient of
friction, such as for example by roughening the inside of
the bearing shell 16 or the like. At any rate, in this
case too, a frictionally locking connection between rubber
body 5 and stabilizer bar 2 is ensured in operation.
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13
Naturally, during final installation - and only at this
time - it is possible, by overcoming the static friction,
to cause the stabilizer bar 2 to slip through the rubber
body 5 in a controlled manner. The production of the
rubber/metal bearing 1, in particular the vulcanization,
is carried out in a standard manner, such as for example
as described in DE-C 40 25 100.
