Note: Descriptions are shown in the official language in which they were submitted.
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TITLE:
Unitized full complement 4-point angular contact ball bearing
FIELD
The present invention relates to the unification of a full complement 4-point
angular
contact ball bearing.
BACKGROUND
Full complement ball bearings eliminate the cost associated with bearing
cages, and
enable bearings to operate more efficiently in abrasive environments such as
oilfield
downhole tools lubricated with drilling mud. However, many traditional designs
require that
either the inner or outer race be split circumferentially in order to assemble
the bearing. This
causes a problem in handling the bearings as the balls could fall out if the
two piece race
combination is not held tightly together during shipping, handling,
installation, or future tool
maintenance. Unitizing the assembly to prevent the balls from falling out is a
common
problem. Traditional attempts to hold the mating faces together include
temporary tie wires,
mechanical tabs, or some other localized mechanical clamping devise. These
methods have
not proven very successful in rugged applications like those found in oilfield
machinery;
particularly where future maintenance is performed and the bearings are to be
reused. These
methods also require additional manufacturing cost and complex assembly
tooling.
SUMMARY
There is provided a unitized full complement four point angular contact ball
bearing,
which includes an outer race, an inner race and a plurality of rolling
elements positioned
between the outer race and the inner race. One of the outer race or the inner
race consists of
two portions. Each of the two portions includes means for engaging a
circumferential
retainer. A circumferential retainer on one of an inside circumference or an
outside
circumference serves to retain the two portions.
BRIEF DESCRIPTION OF THE DRAWINGS
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These and other features will become more apparent from the following
description in
which reference is made to the appended drawings, the drawings are for the
purpose of
illustration only and are not intended to in any way limit the scope of the
invention to the
particular embodiment or embodiments shown, wherein:
FIG. 1 is a side elevation view, partially in section, of a full complement
four point
angular contact ball bearing with the outer race split circumferentially into
two portions.
FIG. 2 is a section view along the A-A section line of FIG. 1.
FIG. 3 is a more detailed side elevation view of the ball bearing of FIG. 2.
FIG. 4 is a side elevation view, partially in section, of a full complement
four point
angular contact ball bearing with the inner race split circumferentially into
two portions.
FIG. 5 is a section view along the B-B section line of FIG. 4.
FIG. 6 is a more detailed side elevation view of the ball bearing of FIG. 5.
DETAILED DESCRIPTION
A unitized full complement four point angular contact ball bearing generally
identified by reference numeral 10, will now be described with reference to
FIG. 1 through
FIG.6.
Structure and Relationship of Parts:
Referring to FIG. 1, a unitized full complement four point angular contact
ball
bearing 10 is illustrated consisting of an outer race 12, an inner race 14 and
a plurality of
rolling elements. Referring to FIG. 3, a circumferential retainer 18 prevents
separation of
outer race 12 and inner race 14. In the embodiment shown in FIG. 2, outer race
12 consists of
a first portion 20 and a second portion 22. Referring to FIG. 3, first and
second portions 20
and 22, respectively, have first and second circumferential steps 24 and 26,
respectively,
which define a circumferential slot 28 in which circumferential retainer 18 is
engaged. Slot 28
is centred along a substantially central radial plane 30 of ball bearing 10.
Outer and inner
races 12 and 14, respectively, have first and second rounded interior profiles
32 and 34,
respectively. First and second rounded interior profiles 32 and 34,
respectively, together
define a rolling element raceway 36. Each of the plurality of rolling elements
may be standard
balls 16, also known as ball bearings, used in the ball bearing industry. An
example of a
suitable ba1116 may be a rockbit ball. In general each of the plurality of
ball bearings 16 are
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provided as near-perfect spheres in order to reduce friction and wear within
ball bearing 10. It
should be noted that there are numerous shapes, other than balls 16, that the
rolling elements
may take. Referring to FIG. 1, plurality of ball bearings 16 are positioned
between outer and
inner races 12 and 14, respectively, as a full complement.
First and second rounded interior profiles 32 and 34, respectively, are
rounded
acircularly such that balls 16 contact rolling element raceway 36 at four
contact points 38.
Contact points 38 are defined by two axis 46 and 48 perpendicular to one
another that
intersect each other at a center 49 of one of the plurality of ball bearings
16. Each of axis 46
and 48 are oriented substantially forty-five degrees from central radial plane
30. Contact
points 38 are denoted at the points where axis 46 and 48 contact rolling
element raceway 36.
Contact points 38 may be located at different positions along first and second
rounded interior
profiles 32 and 34, respectively, than shown.
Referring to FIG. 1, circumferential retainer 18 is provided as a ring that
extends
three-hundred-sixty degrees around an outside circumference 44 of first and
second portions
and 22, respectively. Referring to FIG. 3, retainer 18 has a first
circumferential profile 50
that includes protrusions 52. Slot 28 has a second circumferential profile 54
that mates with
first circumferential profile 50. It is preferable that first and second
circumferential profles 50
20 and 54, respectively, mate in snap fit relation. Second circumferential
profile 54 has recesses
56 in which protrusions 52 fit into and engage. In this manner, retainer 18
holds first and
second portions 20 and 22, respectively, securely together. Alternatively,
first circumferential
profile 50 may have recesses 56 while second circumferential profile 54 may
have protrusions
52. Furthermore, a circumferential shoulder (not shown) may extend from outer
race 12, in
place of slot 28, with retainer 18 fitting tightly around the circumferential
shoulder in order to
retain first and second portions 20 and 22 together.
Variations:
There will now be described a variation in which the inner race is split in
two and the
circumferential retainer extends around the inside circumference. Referring to
FIG. 4, a
unitized full complement four point angular contact ball bearing 110 is
illustrated consisting
of an outer race 112, an inner race 114, and a plurality of rolling elements.
Referring to FIG.
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6, a circumferential retainer 118 secures outer race 112 and inner race 114
together. In the
example shown in FIG. 5, inner race 114 consists of a first portion 120 and a
second portion
122. Referring to FIG. 6, first and second portions 120 and 122, respectively,
have first and
second circumferential steps 124 and 126, respectively, that defme a
circumferential slot 128
in which circumferential retainer 118 is engaged. Slot 128 is centred along a
substantially
central radial plane 130 of ball bearing 110. Outer and inner races 112 and
114, respectively,
have first and second rounded interior profiles 132 and 134, respectively.
First and second
rounded interior profiles 132 and 134, respectively, together define a rolling
element raceway
136. Each of the plurality of rolling elements may be standard balls 116, also
known as ball
bearings, used in the ball bearing industry. An example of a suitable ball 116
may be a rockbit
ball. In general each of the plurality of ball bearings 116 are provided as
near-perfect spheres
in order to reduce friction and wear within ball bearing 110. It should be
noted that there are
numerous shapes, other than balls 116, that the rolling elements may take.
Referring to FIG.
4, plurality of ball bearings 116 are positioned between outer and inner races
112 and 114,
respectively, in a full complement.
First and second rounded interior profiles 132 and 134, respectively, are
rounded
acircularly such that balls 116 contact rolling element raceway 136 at four
contact points 138.
Contact points 138 are defmed by two axis 146 and 148 perpendicular to one
another that
intersect each other at a center 149 of one of the plurality of ball bearings
116. Each of axis
146 and 148 are oriented substantially forty-five degrees from central radial
plane 130.
Contact points 138 are denoted at the points where axis 146 and 148 contact
rolling element
raceway 136. Contact points 138 may be located at different positions along
first and second
rounded interior profiles 132 and 134, respectively, than shown.
Referring to FIG. 4, circumferential retainer 118 is provided as a ring that
extends
three-hundred-sixty degrees around an inside circumference 144 of first and
second portions
120 and 122, respectively. Referring to FIG. 6, retainer 118 has a first
circumferential profile
150 that includes protrusions 152. Slot 128 has a second circumferential
profile 154 that
mates with first circumferential profile 150. It is preferable that first and
second
circumferential profiles 150 and 154, respectively, mate in snap fit relation.
Second
circumferential profile 154 has recesses 156 in which protrusions 152 fit into
and engage. In
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this manner, retainer 118 holds first and second portions 120 and 122,
respectively, securely
together. Alternatively, first circumferential profile 150 may have recesses
156 while second
circumferential profile 154 has protrusions 152. Furthermore, a
circumferential shoulder (not
shown) may extend from inner race 114, in place of slot 128, with retainer 118
fitting tightly
5 around the circumferential shoulder in order to retain first and second
portions 120 and 122
together.
Advantages:
Bearings 10 and 110 enable a number of individual bearings to be handled
during the
installation and maintenance of a multi-high stacked assembly, without mixing
up the races or
having the balls falling out. The retaining ring of bearings 10 and 110, with
positive
circumferential snap engagement, solves both the axial retention and
manufacturing issues. A
greater axial retention force is obtained from a 360 degree snap and, because
no tooling is
required, the design lends itself to low volume customization.
In this patent document, the word "comprising" is used in its non-limiting
sense to
mean that items following the word are included, but items not specifically
mentioned are not
excluded. A reference to an element by the indefinite article "a" does not
exclude the
possibility that more than one of the element is present, unless the context
clearly requires that
there be one and only one of the elements.
The following claims are to understood to include what is specifically
illustrated and
described above, what is conceptually equivalent, and what can be obviously
substituted.
Those skilled in the art will appreciate that various adaptations and
modifications of the
described embodiments can be configured without departing from the scope of
the claims.
The illustrated embodiments have been set forth only as examples and should
not be taken as
limiting the invention. It is to be understood that, within the scope of the
following claims,
the invention may be practiced other than as specifically illustrated and
described.
