Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to rolling element bearings.
Rolling element bearings usually comprise an outer ring,
an inner ring, a plurality of rolling elements such as balls or
rollers and a cage for guiding and separating the rolling
elements. The majority of standard bearing rings are of
solid cross-section, machine turned from high-quality and
high-cost bearlng metal tube. Bearing rings are, therefore
expensive, not only because they are made entirely of expensive
material, but also because the machining necessary to form tllem
is costly and results in a large ~astage of metal as swarf.
~~~The present invention provides a rolling element bearing
comprising inner and outer races or rings with a plurality of
rolling elements therebetween, at least one of the rings being
o~ composite form with a "relatively thin" metal track member
-engaging the rolling elements, a "relatively thin" metal
support, and a resilient packing mounted between the track member
and the support, u~herein the packing is adhesively bonded to
the track member an~ the support and is maint~ined therebett~een
in a state of compression.
The term "relatively thin" is used throughout this
specification to indicate that the metal members so described
are thin when compared with the thickness of a comparable
standard solid bearing ring, but which are thick enough to
~ulfil their required functions in the completed composite ring.
The track member of the composite ring may be preformed
by rolling a tube, preferably made of bearing steel. The
support of the composite ring may also be prefoTmed ~y rolling
a ~`ube,~prëf~ra~ly-~-ade of mild steel. Such a ring ~hus needs
ise high ~ua]ity be~ring steel only for the tra~ member
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itsel`f. Consequently, there is a smaller amount of high
quality bearing steel used in such a ring than in a com-
parable solid ring. Moreover, as the track member is made
by rolling there is little or no waste material. As the
suppor-t is also made by a rolling process so again there
no macini~grequired in its formation. The resilient
packing gives the ring the required rigidity which it
would otherwise lack owing to the utilisation of the
thin track and support members.
Advantageously, the track member of the composite
ring has a thickness lying in the range of from 50
thou. to 100 thou., and preferably it has a thickness of
60 thou.
Advantageously, the support of the composite ring
has a thickness lying in the range of from 20 thou. to
100 thou., and preferably it has a thickness of 50 thou.
Advantageously, the resilient packing of the com-
posite ring completely fills -the space between the track
member and the support.!, Because the packing is enclosed
between the track member and the support in a compressed
state, the load carrying capacity of the bearing is
increased and any localised spreading of the packing is
prevented when the bearing is under load.
The packing or core of the composite ring may be
made of rubber or polymeric material and may be pre-
moulded to the desired shape or formed in situ by a
compression or injection moulding process.
The resilient packing of the composite ring may also
take the fo~m of a strip of resilient material, preferably
100 thou. thick.
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-~ (,A bearing made in accordance with the invention
; may further comprise a respective dust shield covering
each of the annular
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gaps betweell the inner and outer rings.
Preferably, at least one o the dust shields is held between
the resilient packing and a respective inturned flange of the
support o-~ the composi.te ring or one of the composite rings.
Alternatively, at least one of the dust shields is held in a
respective groove formed in one of the rings. In either case,
each dust shield may be a light pressing of mild steel 10 thou.
¦thick and may be provided at its ree edge, wi-th a polymeric
seal bonded thereto.
Several forms o rolling element bearings each
accommodating at least one composite ring and constructed
in accordance with the invention will now be described, by
way of example, with reference to the accompanying drawin~s,
in which:-
-~igure 1 is-a cross-section-taken through a first form F
of ball bearing, the bearing having both rings o composite
structure;
Figure 2 is a cross-section taken through a second orm
of ball bearing, t~e bearing having both rings o composite
structure;
Figure 3 is a cross section taken through part of a first
form o~ roller bearing having a composite outer ring; '
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; Fig. 4 is a cross-section taken through part of a
third. form of ball bearing, the bearing
having a composite outer ring;
Fig. 5 is a cross-section taken through a fourth i
form of ball bearing, the bearing having a
composite outer ring;
-Figs. 6 and 7 are schematic- representations of the
composite outer rings of second and third
forms of roller bearing; and
; Fig. 8 is a cross-section through part of a fifth
form of ball bearing.
Referring to the drawings, Fig. 1 shows a bearing of
outside deameter 2.5 inches, bore 1 inch and width 0.75
inch. The bearing has an outer ring, indicated generally
by the reference numeral 1, an inner ring, indica-ted gen-
erally by the reference numeral 5, a plurality of balls 9
(only one of which can be seen) and a cage 10 for guiding
and separating the balls. The outer ring 1 comprises an
outer shell 2 of 50 thou. mild steel preformed by rolling
from a tube, a track member 3 of 60 thou. bearing steel,
also preformed by rolling tube, and resilient packing or
core 4 made of rubber, the core 4 being bonded,to the
shell 2~and the track member 3 by means of an adhesive.
The core 4 is preformed into the required shape by a 1~l
moulding process. The inner ring 5 similarly comprises
a shell 6 made of 50 thou. rolled mild steel, a track
member 7 made of 60 thou. rolled bearing steel and a
resilient packing or core 8 of rubber, the core 8 being
bonded to the shell 6 and the track member 7 be means
of an adhesive.
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Fig. 2 shows a bearing similar to that o~ F`ig. 1
; and having an outer ring, indicated generally by the-~
reference numberal ll, an inner ring, indicated generally
by the reference numberal 15,
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a plurality of ball 19 (only one of which aan be seen) and
a cage 20 for guiding and separating the balls. The outer
ring 11 has a two-piece outer shell 12a, 12b, each pd~ece
of which is made of 50 thou. rolled mild steel, a two-piece
track member 13_, 13_, each piece of which is made of 60
thou. rolled bearing steel, and a resilient packing or core
14 made of rubber. The core 14 is compression moulded to
the track member pieces 13a, 13b, and is so formed tha-t,
when the shell pieces 12a, 12b, are pushed on into posi-
tion the rubber and hence the track member pieces are in
a state of compression. A lubrication hole 12c, is pro-
vided ln the outer shell and this hole communicates with
the interior of the bearing via a hole 14a provided in
the core 14 and a cut-out 13c formed in the inturned
edges 13a', 13_' of the track member pieces 13a,13_.
rChe inner ri~ng 15 is(~similar to the ring 5 of the embodi-
ment of Fig. 1 and comprises a shell 16 made of 50 thou.
rolled mild steel, a track member 17 made of 60 thou.
rolled bearing steel and a core 18 of rubber, the core
18 being bonded to the shell 16 and the track member 17
by means of an adhesive.
Fig. 3 shows part of a roller bearing having an
outer ring, indicated generally by the reference numberal
21, an inner ring 25, a plurality of rollers 29 (only
one of which can be seen) and a cage 30 for guiding and
separating the rollers. The outer ring 21 has a two-piece
outer shell 22a, 22b, each piece being made of 50 thou.
rolled mild steel, a track member 23 made of loo thou.
rolled bearing steel, and a resilient packing or core 24
made of rubber, the core 24 being bonded to the shell
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pieces 22a, 22b, and to the track member 23 by means of
. an adhesive. The inner ring 25 is a standard bearing
ring turned from stock bearing steel
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tube 150 thou. thick. ~ 9~6
In each of the composite rings 1, 5, 11, 15 and 21
described above, it core 4,8 14, 18 and 24 respectively ls
enclosed between it corresponding shell/track member
combinations in a compressed state. This increases the
load carrying capacity of the bearing and also prevents
any localised spreading of the core when the bearing is
under load.
Each of the composite rings 1,5,11,15 and 21 has a
number of advantages over rings made in the conventional
manner. Firstly, there is a saving in the machining
costs and on materials used as there is little or no
scrap metal to be discarded in forming the shell and
track members. The required rigidity is given to each of
the rings by means of its bonded resilient core which per-
mits the manufacture of the.shells and track members from
relatively thin metal. The shells may be made of thinner
material than that deseribed, it being envisaged that shell
thieknesses of 20 thou. are possible when rolled mild steel
is used for the shell material. The cores also damp noise
and vibrations and so ensure smoother and quieter running.
The cores also are eapable of absorbing impaet loads on
the bearing whieh eould otherwise fail owing to high
stresses on the balls and rings. Thus, high eost hard
béaring-metal need only be used for the relatively thin
traek members and so a further eost saving is effeeted.
Moreover, sueh a eore aets as an eleetrieal ins~lating
layer isolating the two rings and so preventing the
possibility of eleetrieal discharges across the ball/ring
in-terfaees whieh eould eause surfaee distress leading to
early bearing failure. Furthermore, eaeh of these
bearings has a inbuilt degree of eomplianee owing to
~ resilient
1(;~4~
core or cores and this tends to alleviate any shaft to
housing misalignments that may occur when the bearing is
set up. Although, such misalignments are usually of a
smaller order, they do resul-t in increased stress and
consequently are detrimental to -the life of a bearing.
Figs.; 4 and 5 show bearings each having a composite
outer ring and each being adapted for a special purpose.
In each case the shelll and track members are shaped by
cold forming, the shell and track members being of mild
steel and bearing steel respectively, and the cores are
made of premoulded rubber bonded to the corresponding shell
and track members. Thus, Fig. 4 shows a bearing comprising
an outer ring, indicated generally by the reference
numeral 31, an inner ring 35 ahd a plurality of balls 39
(only one of which can be seen). The outer ring 31 com
prises a two-piece outer shell 32a, 32b, a track member
33 and a resilient packing or core 34. The outer ring 31
is held within a compressive sleeve 36 fast to a housing
37 and the inner ring 35 is rotatable with a shaft (not
shown). The sleeve 36 applies axial compressive forces
(as indicated by the arrows A) to the shell piece 32a and
32b and these forces are transmitted through the core 34
(as indicated by the arrows b) tot he -track member 33.
This track member 33 is arched slightly so as to leave a
small gap 38 between the track member and the balls 39.
Thus, the track member 33 can be deformed inwardly to give
an adjustment for radial ball to raceway groove clearance
should this be required. An e~ternal annular groove 33a
in the track member 33 mates with a corresponding pro~
jection 34a of the core 34 to increase the flexibility of
the track member 33 and so facilitate its inward radial
deforma-tion.
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Fig. 5 shows a bearing having an L-shaped outer ring,
indicated generally by the referance numeral 41, an inner ring 45,
and a plurali~y of balls 49 (only two of which can be seen), The
outer ring 41 comprises a two-piece shell 42a, 42b, an L-shaped
member 43 provided with a track surface 43a and a resilient packing
or core 44. The bea~ing is adapted to be attached by means of
bolts 46 (only one of which can be seen) to a housing 47. The
advantage of such an arrangement, particularly for machinery such
as agricultural machinery, is that the housing can be machined to
the required shape to accommodate the~bearing which can then be
dropped into place and bolted onto the housing. This removes the
need for the end caps and sleeves which are normally required to
mount such bearings.
The track members 33 and 43 and the shell pieces 32a,
32b and 42a, 42b of the Fig. 4~and Fig. 5 embodiments are made of
60 thou. rolled bearing steel and 50 thou. rolled mild steel
respectively.
Figs. 6 and 7 show schematically two further forms of
roller bearing, each being similar to that of Fig. 3, but depicted
without the inner ring and roller elements. Fig. 6 shows an outer
ring, indicated generally by the reference numeral 51, comprising
a two-piece outer shell piece 52a, 52b (each piece being made of
50 thou. rolled mild steel3~ a track member 53 made of 100 thou.
rolled bearing steel and a resilient packing or core 54 made of
a strip of rubber 100 thou. thick. The shell pieces 52a, 52b
are formed so as to define a flange 52c which facilitates
installation of the bearing. The core 54 is bonded to the track
member 53 and to the shell piece 52b. The cross-section of the
laminated layer 52b, 54, 53 may be slightly thicker at the middle
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than at its ends so as to provide a more unifor:m load dis-
tribution from the track -to the rollers (not shown). The
bearing of Fig. 7 is identical to that of Fig. 6 except it
has -two shell-pieces 62a and 62b of complementary shape
which are spot welded -together to define a central flange
62c.~
Fig. 8 shows part of a bearing similar to that sho~n
in Fig. 1, the bearing having an outer ring, indicated
generally by the reference numeral 71, an inner ring 75,
a plurality of balls 79 (only one of which can be seen)
and a cage 80 for guiding and separating the balls. The
outer ring 71 is similar to outer ring 1 of Fig. 1 in that
it comprises an outer shell 72 or 50 thou. mild steel, a
track member 73 of 60 thou. bearing steel and a resilientpacking
core 74 made of rubber, the core being bonded to the shell
and to the track member by an adhesive. A dust sh~eld 76
made of 10 thou. mild steel is provided at each side of
the bearing, the shields being inserted between the core
74 and the shell 72. A seal 77 made of polymeric material
is moulded to the opposite end of each shield 76 and is
arranged to seal against the inner ring 75. In conventional/
bearings difficulties frequently arise from the fitting
of dust shields and seals. Thus, where a shield is in-
serted into a groove in a bearing ring, -the act of inser-
tion can cause the ring (and its integrally formed raceway)
to deform from true roundness to the detriment of bearing
performance. This shortcoming is overcome in this bearing
as any distortion introduced by the introduction of the ,
shields 76 partly taken up by the compliance of the resi-
lient core 74. Any distortion not taken up by the core 74
is limited to a distortion of the outer shell 71 and so the
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track member 73 is unaffected. It is also possible
to fit the shields 76 into grooves formed in the shell
72. Here
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again, any distortion is taken up by the shell 7~ and the track
member 73 is unaffected. Obviously, dust shields and seals
similar to 76 and 77 could be fitted to the bearings described
with reference to Figs. 1 to 7.
The bearings described with reference to the
accompanying drawings may be modified in a number of ways.
Thus, the resilient packing or cores may be made of resilient
plastics material instead of rubber. Moreover, these cores
may be formed in situ by an injection moulding processO
