Note: Descriptions are shown in the official language in which they were submitted.
108636S
UNIVERSAL BEARING JOINT
This application is a division of application `;-
Serial ~o. 283514 filed July 26, 1977
Background of the Invention
Field of the Invention. This invention relates-to
universal joint assemblies of the yoke and cross type and,
more particularly, to the trunion bearing mounting arrangement
which tends to dissipate the operational loads over a number
of needle bearing elements.
Description of the Prior Art. A typical prior art universal
joint assembly includes a cross operationally connected to two
yokes; there being needle bearing elements interposed between
the trunions of the cross and the bearing cup associated with
the yoke. The point of operational loading of this arrangement
is such that the single needle bearing element located at that
point assumes substantially the entire load. Obviously, the
load is generally equally divided amongst each of the four
trunion - needle bearing - bearing cup arrangement. Accordingly, ~ ;
as each needle bearing element or roller traverses the
cylindrical bearing cavity, it is in its unIoaded state until
it reaches the loading point and at that time becomes generally
the only needle bearing element supporting the operational load.
This inefficient use of the various needle bearing elements
may result in galling of the bearing surfaces on each of the -
trunions and/or the inner bearing surface of the bearing cups
and similarly a galling or deterioration of the needle bearing
elements.
Summary of the Invention
Accordingly, it is an important object of the present in-
vention to dissipate the load experienced at each of the
trunion - needle bearing - bearing cup arrangement amongst a
number of needle bearing elements thereby improving the bearing
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characteristics of the universal.joint and.the prolongation
of its operational life.
. It is another object of the present invention to provide
a bearing cup and a series of needle bearing elements
interposed between the inner surface of the cup and the
journal with means provided to bias the needle bearing
elements into intimate roller bearing contact with the
outer bearing surface of the journal and the bearing cup.
To this end, the invention consists of a bearing for re-
ceiving a journal comprising: a bearing cup, a series of
needle bearing elements interposed between the inner surface
of said cup and said journal, means to form a slightly
elliptical path for said needle bearing elements as they re-
volve around said journal thereby bringing said needle bear-
ing elements into intimate rolling bearing contact with the
outer bearing surface of said journal and the inner bearing
surface of said cup, said journal is a trunion formed on
the ends of each of four e~uiangularly spaced arms of a
cross in a cross and yoke type universal coupling, a bearing
cup being mounted on each of said trunions, said means to
bias said needle bearing elements into intimate rolling con-
tact with the outer bearing surface of said trunion and said
inner bearing surface of said bearing cup is an insert member
mounted on each of said trunions, said insert member mounted
on each of said trunions having an inner cylindrical ~urface
in contact with the complementary outer surface of said
trunions, the outer surface of said insert member being
slightly elliptical with respect to the cylindrical inner
surface of said bearing cup, said needle bearing elements
interposed in a bearing relationship between the cylindrical
inner surface of said
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1086365
bearing cup and the outer elliptical surface of said bearing
cup and the outer elliptical surface of said insert member.
Other features of an embodiment of the present invention
and details of the structure of the universal bearing joint
will appear more fully from the following description and
accompanying drawings.
Description of the Drawings
Figure 1 is the universal bearing joint embodying the
present invention:
Figure 2 is an end sectional view of the trunion -
needle bearing - bearing cup arrangement taken along the
line 2-2 of Figure l;
Figure 3 is an end sectional view of a universal joint
including an embodiment that is claimed in the parent
application referred to above; and
Figure 4 is an end sectional view of a universal joint
including an embodiment of the present invention.
Description of the Preferred Embodiments
Referring to the drawings and particularly Figures 1 and
2, there is shown a universal joint 10 which is adapted to
transmit motion in a suitable power train. In view of the
fact that couplings of this general type are well known in
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108636S
~!^' the prior art, it is believed unnecessary to set forth a detailed description of
their construction other than that they include a cross or spider 12 having two
pair of axially aligned, equi-axially spaced arms 14 that are each provided withtrunions 16. The trunions 16 are each adapted to be received in a bearing cup 18and such bearing cups 18 are adapted to be mounted or attached to the arms of a
driving or driven yoke tnot shown).
It is at the trunion end of the universal joint 10 that the thrust of the
present invention is to be found. More particularly, the present invention is
directed to the relationship of the trunion surface 16 which, in effect, is a
10 bearing surface and the plurality of needle bearings 20 which are in bearing
relationship between the trunion 16 and the inner bearing surface 22 of the
bearing cup 18. The major objective and thrust of the present invention, as
before mentioned, is to provide a universal joint 10 in which the force
transmitted through the universal joint and particularly that force experienced
by and between the needle bearings is experienced nat by b single or few needle
bearings but is dissipated over a number of needle bearings 20.
This basic objective of the present invention is to provide means to
bias the needle bearing elements 20 into intimate rolling contact with the trunion
16 and the inner bearing surfaces 22 of the bearing cup 18. This can be achieved20 by forming the inner bearing surface 22 of the bearing cup 18 in a slightly
elliptical manner and, more particularly, to form the inner bearing surface 22 of
the bearing cup 18 in an ellipse wherein the lesser diameter of the elliptical
surface is generally disposed 9û from the maximum loading point occurring
when the universal joint 10 is operationally transmitting a load from the driving
yoke to the driven yoke and the major diameter of the elliptical surface being
formed such that it coincides with the maximum loading point. This elliptical
surface 22, in effect, brings a plurality of needle bearings into intimate contact
with their respective bearing surfaces including the trunions 16 thereby ensuring
that the operational load will be seen by at least several of such needle bearings.
3û This is to be contrasted with the prior art forms of universal joints wherein only
generally two needle bearings of each trunion cup arrangement see and
experience the operational load at one time.
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~0~6365
The needle bearings 20 can be brought into intimate
contact with their respective bearing surfaces in a number
of ways which will be further explained below. These
additional modes of load dissipation are generally shown
in Figures 3 and 4.
Referring now to Figure 3, there is shown a partial
sectional view of an arrangement claimed in the parent
application, wherein the bearing cup 24 is provided with an
insert member 26. The insert member 26 may be pressfitted
within the bearing cup 24 and fixedly attached thereto.
The inner surface of the insert member 26 may be formed
~ slightly elliptical in a fashion similar to the slightly
elliptical inner bearing surface of the bearing cup 18. This
is to say the insert member 26 provides at its inner surface
a slightly elliptical surface against which the needle
bearings 28 bear.
~ eferring now to Figure 4, there is shown a sectional
view of an embodiment of the present invention, wherein a
collar or sleeve type insert member 30 is pressed on each
trunion in an interference fit relationship. The outer
surface of the insert member 30 may be formed in a slightly
elliptical fashion comparable to those mentioned above.
That is to say that the insert member 30 provides at its
outer surface the slightly elliptical surface against which
the needle bearings 34 bear.
It should be noted that to enhance the lubricity and
bearing characteristics of the above-referenced universal
bearing joint configurations various bearing surfaces may
be coated with a suitable self-lubricating material as
polytetrafluroethylene. It should be noted that the above-
noted insert members 26 and 30 could be particularly useful
1086365
in retro-fitting existing universal joints which are provided
with complementary cylindrical trunions and inner bearing
surfaces provided on the bearing cups.
It can be seen, therefore, from the above that the
thrust of the present invention is to bring a plurality of
needle bearings into intimate contact with their respective
bearing surfaces particularly when they are subjected to
an operational load. This approach avoids exposing the
needle bearings independently to a full load situation as
they revolve around the trunions. This invention, therefore,
includes forming the various bearing sùrfaces such that the
needle bearings traverse a slightly elliptical path and,
additionally, it should be noted that the needle bearings
may be biased or preloaded against the bearin~ surfaces.
It is, therefore, obvious that the present invention is
not to be limited to the specific details of the universal
bearing joint above described; but is capable of other
modifications and changes without departing from the spirit
and scope of the appended claims.
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