U.S. patent application number 14/563659 was filed with the patent office on 2015-04-02 for methods of operating roller bearing apparatuses including compliant rolling elements.
The applicant listed for this patent is US SYNTHETIC CORPORATION. Invention is credited to Craig H. Cooley, David P. Miess, S. Barrett Peterson.
Application Number | 20150093064 14/563659 |
Document ID | / |
Family ID | 49885469 |
Filed Date | 2015-04-02 |
United States Patent
Application |
20150093064 |
Kind Code |
A1 |
Peterson; S. Barrett ; et
al. |
April 2, 2015 |
METHODS OF OPERATING ROLLER BEARING APPARATUSES INCLUDING COMPLIANT
ROLLING ELEMENTS
Abstract
In an embodiment, a roller bearing apparatus may include a rotor
having first superhard raceway elements distributed
circumferentially about an axis. Each first superhard raceway
element includes a raceway surface positioned/configured to form a
first portion of a raceway. The apparatus includes a stator
including second superhard raceway elements generally opposed to
the first superhard raceway elements. Each second superhard raceway
element includes a raceway surface positioned/configured to form a
second portion of the raceway. The apparatus includes rolling
elements interposed between the rotor and stator and positioned and
configured to roll on the raceway. One or more of the rolling
elements may be configured to elastically deform on the raceway
during use. At least a portion of the raceway exhibits a first
modulus of elasticity greater than a second modulus of elasticity
of at least a portion of the one or more of the rolling
elements.
Inventors: |
Peterson; S. Barrett; (Orem,
UT) ; Cooley; Craig H.; (Saratoga Springs, UT)
; Miess; David P.; (Highland, UT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
US SYNTHETIC CORPORATION |
Orem |
UT |
US |
|
|
Family ID: |
49885469 |
Appl. No.: |
14/563659 |
Filed: |
December 8, 2014 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13713096 |
Dec 13, 2012 |
8939652 |
|
|
14563659 |
|
|
|
|
Current U.S.
Class: |
384/565 |
Current CPC
Class: |
F16C 2206/04 20130101;
F16C 19/30 20130101; F16C 2202/08 20130101; F16C 2202/06 20130101;
F16C 19/28 20130101; F16C 19/163 20130101; F16C 17/028 20130101;
F16C 43/06 20130101; F16C 19/22 20130101; F16C 19/06 20130101; F16C
33/34 20130101; F16C 2202/04 20130101; F16C 19/547 20130101; F16C
21/00 20130101; Y10T 29/49689 20150115; F16C 19/46 20130101; F16C
17/047 20130101; F16C 19/36 20130101; F16C 33/32 20130101; F16C
33/62 20130101; Y10T 29/49684 20150115; F16C 19/26 20130101; F16C
33/585 20130101 |
Class at
Publication: |
384/565 |
International
Class: |
F16C 33/34 20060101
F16C033/34; F16C 33/58 20060101 F16C033/58; F16C 19/22 20060101
F16C019/22; F16C 33/62 20060101 F16C033/62 |
Claims
1. A method of operating a bearing assembly that includes a first
raceway and a second raceway, the method comprising: rotating the
first raceway relative to the second raceway, the first raceway
including a plurality of first superhard raceway elements having a
first modulus of elasticity; rolling one or more rolling elements
between the first and second raceways and on the plurality of first
superhard raceway elements, the one or more rolling elements having
a second modulus of elasticity that is three (3) times greater to
about fifty (50) times greater than the first modulus of
elasticity.
2. The method of claim 1, wherein rotating the first raceway
relative to the second raceway causes the rolling of the one or
more rolling elements.
3. The method of claim 1, wherein rolling one or more rolling
elements between the first and second raceways and on the plurality
of first superhard raceway elements includes rolling the one or
more rolling elements in contact with at least some of the
plurality of first superhard raceway elements.
4. The method of claim 1, wherein the second raceway includes a
plurality of second superhard raceway elements, and wherein rolling
one or more rolling elements between the first and second raceways
and on the plurality of first superhard raceway elements includes
rolling the one or more rolling elements in contact with one or
more of the plurality of first superhard raceway elements and the
plurality of second superhard raceway elements.
5. The method of claim 1, wherein the one or more rolling elements
include a superelastic material.
6. The method of claim 1, wherein the second raceway includes a
plurality of second superhard raceway elements generally opposing
the plurality of first superhard raceway elements.
7. The method of claim 1, wherein each of the first and second
raceways is substantially planar, substantially cylindrical, or
substantially conical.
8. The method of claim 1, wherein one or more of the plurality of
first superhard raceway elements include a concavely-curved raceway
surface or a convexly-curved raceway surface.
9. The method of claim 1, wherein at least some of the plurality of
first superhard raceway elements include polycrystalline
diamond.
10. The method of claim 1, wherein the first raceway, the second
raceway, and the one or more rolling elements form a radial bearing
assembly, a thrust-bearing assembly, or a tapered bearing
assembly.
11. The method of claim 1, wherein the first plurality of superhard
raceway elements includes gaps between adjacent ones of the
plurality of first superhard raceway elements, and wherein one or
more of the first plurality of superhard raceway elements include
at least one side surface forming a respective oblique angle
relative to the axis, and wherein the respective oblique angle is
selected to at least partially inhibit the gaps from impeding the
one or more rolling elements during operation.
12. The method of claim 11, wherein the respective oblique angle is
greater than about forty (40) degrees.
13. The method of claim 11, wherein the respective oblique angle is
greater than about forty (40) degrees.
14. A method of operating a bearing assembly, the method
comprising: rotating a first raceway relative to a second raceway,
the first raceway including a plurality of first superhard raceway
elements having a first modulus of elasticity, and the second
raceway including a plurality of second superhard raceway elements;
rolling one or more rolling elements between the first and second
raceways and on the plurality of first superhard raceway elements
and the plurality of second superhard raceway elements, the rolling
elements including one or more superelastic materials.
15. The method of claim 14, wherein the one or more rolling
elements are generally elongated rolling elements.
16. The method of claim 15, wherein the generally elongated rolling
elements include a core body at least partially surrounded by the
one or more superelastic materials.
17. The method of claim 15, wherein the generally elongated rolling
elements includes a hollow cylindrical body.
18. The method of claim 15, further comprising a cage that retains
the generally elongated rolling elements between the first raceway
and the second raceway.
19. A method of operating a bearing assembly, the method
comprising: rotating a first raceway relative to a second raceway,
the first raceway including a plurality of first superhard raceway
elements having a first modulus of elasticity, and the second
raceway including a plurality of second superhard raceway elements;
rolling one or more rolling elements between the first and second
raceways and on the plurality of first superhard raceway elements
and the plurality of second superhard raceway elements, one or more
of the plurality of first superhard raceway elements or the
plurality of second superhard raceway elements having a thermal
conductivity of at least 300 W/m-K.
20. The method of claim 19, wherein the thermal conductivity is
about 700 W/m-K to about 1600 W/m-K.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 13/713,096 filed on 13 Dec. 2012, the disclosure of which is
incorporated herein, in its entirety, by this reference.
BACKGROUND
[0002] Roller bearing apparatuses are found in a variety of
applications from wind turbines to mining equipment. Typically,
roller bearing apparatuses include two races, a plurality of
rolling elements between the races, and a roller assembly that
separates and guides the rolling elements. Usually one of the races
is held fixed. As one of the races rotates, it causes the rolling
elements to rotate as well which, in turn, reduces rotational
friction between the races. In addition to reducing rotational
friction, roller bearing apparatuses typically support bearing
loads by transmitting loads between the rolling elements and the
races.
[0003] However useful, roller bearing apparatuses tend to wear out
with use and/or fail without warning. For example, wind turbine
gear boxes commonly suffer bearing failure at about one fifth of
the designed life expectancy. Many of these bearing failures result
from micro pitting, race scuffing, galling, overheating, fatigue
failure, flaking, fretting, and other damage due to friction and/or
repeated loading and unloading of the rolling elements on the
races.
[0004] Therefore, manufacturers and users of roller bearing
apparatuses continue to seek improved roller bearing apparatus
designs and manufacturing techniques.
SUMMARY
[0005] Various embodiments of the invention relate to roller
bearing apparatuses that include relatively compliant rolling
elements. The various embodiments of the bearing assemblies and
apparatuses may be used in pumps, wind turbines, transmissions,
subterranean drilling systems, and other types of systems.
[0006] In an embodiment, a roller bearing apparatus may include a
rotor having a first plurality of superhard raceway elements
distributed circumferentially about an axis. Each of the first
superhard raceway elements includes a raceway surface positioned
and configured to from a first portion of a raceway. The rotor also
includes a first support ring that carries the first superhard
raceway elements. The roller bearing apparatus also includes a
stator including a second plurality of superhard raceway elements
generally opposed the first superhard raceway elements. Each of the
second superhard raceway elements includes a raceway surface
positioned and configured to form a second portion of the raceway.
The stator also includes a second ring that carries the second
superhard raceway elements. The roller bearing apparatus also
includes a plurality of rolling elements interposed between the
rotor and the stator and positioned and configured to roll on the
raceway. One or more of the rolling elements may be further
configured to elastically deform on the raceway during use.
[0007] In an embodiment, at least a portion of the raceway exhibits
a first modulus of elasticity greater than a second modulus of
elasticity of at least a portion of the one or more of the rolling
elements. For example, the first modulus of elasticity may be about
three (3) times greater to about fifty (50) times greater than the
second modulus of elasticity.
[0008] In an embodiment, one or more of the rolling elements may
include one or more superelastic materials that exhibit non-linear
deformation during use. For example, the superelastic material may
include a superelastic nickel-titanium alloy.
[0009] Further embodiments are directed to methods of manufacturing
any of the disclosed roller bearing apparatuses.
[0010] Other embodiments include applications utilizing the
disclosed roller bearing assemblies and apparatuses in various
types of pumps, transmission, wind turbines, drilling systems and
other applications.
[0011] Features from any of the disclosed embodiments may be used
in combination with one another, without limitation. In addition,
other features and advantages of the present disclosure will become
apparent to those of ordinary skill in the art through
consideration of the following detailed description and the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The drawings illustrate several embodiments of the
invention, wherein identical reference numerals refer to identical
or similar elements or features in different views or embodiments
shown in the drawings.
[0013] FIG. 1A is an isometric cutaway view of a radial roller
bearing apparatus according to an embodiment;
[0014] FIG. 1B is an exploded isometric view of the radial roller
bearing apparatus shown in FIG. 1A;
[0015] FIG. 1C is a cross-sectional view taken along line 1C-1C of
the inner race shown in FIG. 1A;
[0016] FIG. 1D is an isometric view of one of the superhard raceway
elements shown in FIG. 1C;
[0017] FIG. 1E is an isometric view of one of the roller elements
shown in FIG. 1B according to an embodiment;
[0018] FIG. 1F is a cross-sectional view taken along line 1F-1F of
the roller element shown in FIG. 1E;
[0019] FIG. 1G is a cross-sectional view of a roller element
according to another embodiment;
[0020] FIG. 1H is a cross-sectional view of a roller element
according to another embodiment;
[0021] FIG. 1I is a partial side elevation view of the inner race
and one of the rolling elements shown in FIG. 1A;
[0022] FIG. 1J is a partial cross-sectional view of the inner race
and one of the rolling elements shown in FIG. 1A;
[0023] FIG. 2A is an exploded isometric view of a radial roller
bearing according to according to another embodiment;
[0024] FIG. 2B is an exploded isometric view of a radial roller
bearing according to another embodiment;
[0025] FIG. 3 is an isometric cutaway view of a radial roller
bearing according to another embodiment;
[0026] FIG. 4 is an exploded view of a tapered roller bearing
apparatus according to another embodiment;
[0027] FIG. 5 is an isometric cutaway view of an angular contact
bearing according to another embodiment;
[0028] FIG. 6 is a partial isometric cutaway view of a rotary
system according to an embodiment;
[0029] FIG. 7 is an isometric cutaway view of a thrust roller
bearing apparatus according to an embodiment;
[0030] FIG. 8 is an exploded isometric view of a tapered thrust
roller bearing apparatus according to another embodiment; and
[0031] FIG. 9 is a schematic isometric cutaway view of a
subterranean drilling system that may utilize any of the disclosed
roller bearing apparatuses according to various embodiments.
DETAILED DESCRIPTION
[0032] Embodiments of the invention relate to roller bearing
apparatuses that include rolling elements (e.g., superelastic,
metallic, or non-superabrasive rolling elements), motor assemblies
that include such roller bearing apparatuses, and related methods.
FIG. 1A is an isometric view of a radial roller bearing apparatus
100 and FIG. 1B is an exploded isometric view of the radial roller
bearing apparatus 100. The radial roller bearing apparatus 100 may
be used in a wind turbine, a pump, a transmission, or other type of
system.
[0033] As shown in FIGS. 1A and 1B, the radial roller bearing
apparatus 100 may include an inner race 102, an outer race 104, and
a roller assembly 106. The inner race 102 (e.g., rotor or stator)
may include a support ring 108 and a plurality of superhard raceway
elements 110. The support ring 108 may define an opening 112
through which a shaft or spindle (not shown) of, for example, a
wind turbine may extend. The outer race 104 (e.g., rotor or stator)
may extend about and receive the inner race 102 and the roller
assembly 106. The outer race 104 may include a support ring 120 and
a plurality of superhard raceway elements 122. The roller assembly
106 may be interposed between the inner race 102 and the outer race
104 and may include a cage 126 and a plurality of rolling elements
128. The superhard raceway elements 110, 122 of the inner race 102
and the outer race 104, respectively, may be configured and
positioned to at least partially define a raceway for the rolling
elements 128. A raceway is a substantially continuous or
discontinuous surface or surfaces over which the rolling elements
128 roll over/run on. Rotation of the inner race 102 and/or the
outer race 104 may cause the rolling elements 128 to roll or run on
the raceway formed between the superhard raceway elements 110 and
the superhard raceway elements 122. As described in more detail
below, the rolling elements 128 and/or the superhard raceway
elements 110, 122 may include one or more features, either alone or
in combination, configured to help reduce wear and/or failure of
(e.g., flaking, strain, pitting, or combinations thereof) of the
radial roller bearing apparatus 100. For example, in an embodiment,
the rolling elements 128 may include one or more metallic materials
(e.g., steel or a superelastic alloy) and/or non-superabrasive
materials and the raceway may include one or more superhard or
superabrasive materials such as polycrystalline diamond,
polycrystalline cubic boron nitride, silicon carbide, tungsten
carbide, or any combination of the foregoing superhard materials.
By varying the material design between the rolling elements 128
and/or the raceway, common failure modes such as welding, galling,
and/or scuffing may be reduced.
[0034] The inner race 102 may form a rotor or a stator of the
radial roller bearing apparatus 100. In the illustrated embodiment,
the support ring 108 is substantially cylindrical and defines the
opening 112. The support ring 108 may be circular and made from a
variety of different materials. For example, the support ring 108
may comprise carbon steel, stainless steel, alloy steel, tungsten
carbide, or another suitable material. In the illustrated
embodiment, the support ring 108 exhibits an inner surface that is
substantially congruent with respect to an outer surface. The
support ring 108 may also include a plurality of recesses 116 (FIG.
1C) formed therein.
[0035] The inner race 102 may also include the plurality of
superhard raceway elements 110 each of which includes a substrate
136 and a superhard table 134 bonded to the substrate 136. The
superhard raceway elements 110 are illustrated being distributed
circumferentially about a rotation axis 114. Each of the superhard
raceway elements 110 may include a convexly-curved raceway surface
118 that defines at least part of the raceway. In the illustrated
embodiment, gaps 132 or other offsets may be located between
adjacent ones of the superhard raceway elements 110. A width of one
or more of the gaps 132 or an average width of the gaps 132 may be
about 0.00020 inches to about 0.100 inches, and more particularly
about 0.00020 inches (0.00508 mm) to about 0.020 inches (0.508 mm).
In other embodiments, one or more of the gaps 132 may exhibit
larger or smaller widths. Optionally, the gaps 132 may be
configured to limit lubricating fluid from being able to leak
between adjacent superhard raceway elements 110. For example, the
gaps 132 may exhibit a relatively small width. As the gaps 132
decrease in size, it may become more difficult for lubricating
fluid to flow between the superhard raceway elements 110. However,
it should be noted that in at least some operational conditions,
entrained lubricating fluid in the gaps 132 may assist with
formation of a hydrodynamic film on at least one of the raceway
surfaces 118. In other embodiments, the gaps 132 may exhibit a
relatively large width. As the width of the gaps 132 increases, the
gaps 132 may be configured to improve heat transfer. For example,
the gaps 132 may be configured to form flow paths for the
lubricating fluid to flow over and/or around the superhard raceway
elements 110. As the size of the gaps 132 increase, fluid flow and
heat transfer may more fully develop between adjacent superhard
raceway elements 110. Thus, by varying the configuration and size
of the gaps 132, the gaps 132 may be optionally configured to
impart a desired amount of heat transfer and/or hydrodynamic film
formation during operation.
[0036] In an embodiment, the gaps 132 may be at least partially
occupied by a portion of the support ring 108. Such a configuration
may increase the contact surface between the support ring 108 and
each of the superhard raceway elements 110 to help affix the
superhard raceway elements 110 to the support ring 108. In other
embodiments, the recesses 116 may be configured and positioned such
that the gaps 132 are omitted. For example, the recesses 116 may be
interconnected to form a slot or channel such that adjacent
superhard raceway elements 110 are adjacent to one another and/or
about one another.
[0037] Referring now to FIG. 1C, each of the superhard raceway
elements 110 may be partially disposed in a corresponding one of
the recesses 116 of the support ring 108 and secured partially
therein via brazing, press-fitting, threadly attaching, fastening
with a fastener, combinations of the foregoing, or another suitable
technique. As used herein, a "superhard raceway element" is a
raceway element including a raceway surface that is made from a
material exhibiting a hardness that is at least as hard as tungsten
carbide.
[0038] In any of the embodiments disclosed herein, the superhard
raceway elements (e.g., superhard raceway elements 110) may be made
from a number of different superhard materials, such as
polycrystalline diamond, polycrystalline cubic boron nitride,
silicon carbide, tungsten carbide, or any combination of the
foregoing superhard materials. For example, superhard raceway
elements having a PCD table may be formed and bonded to a substrate
using an ultra-high pressure, ultra-high temperature ("HPHT")
sintering process. Such superhard raceway elements having a PCD
table may be fabricated by placing a cemented carbide substrate,
such as a cobalt-cemented tungsten carbide substrate, into a
container or cartridge with a volume of diamond particles
positioned on a surface of the cemented carbide substrate. A number
of such cartridges may be loaded into an HPHT press. The substrates
and diamond particles may then be processed under HPHT conditions
in the presence of a catalyst material that causes the diamond
particles to bond to one another to form a diamond table having a
matrix of bonded diamond crystals. The catalyst material is often a
metal-solvent catalyst, such as cobalt, nickel, or iron, which
facilitates intergrowth and bonding of the diamond particles. In an
embodiment, a constituent of the cemented carbide substrate, such
as cobalt from a cobalt-cemented tungsten carbide substrate,
liquefies and sweeps from a region adjacent to the volume of
diamond particles into interstitial regions between the diamond
particles during the HPHT process. The cobalt may act as a catalyst
to facilitate the formation of bonded diamond grains.
[0039] In any of the embodiments disclosed herein, the
polycrystalline diamond table may be leached to at least partially
or substantially completely remove the metal-solvent catalyst
(e.g., cobalt, iron, nickel, or alloys thereof) that was used to
initially sinter precursor diamond particles that form the
polycrystalline diamond. In another embodiment, an infiltrant used
to re-infiltrate a preformed leached polycrystalline diamond table
may be leached or otherwise removed to a selected depth from a
raceway surface. Moreover, in any of the embodiments disclosed
herein, the polycrystalline diamond may be unleached and include a
metal-solvent catalyst (e.g., cobalt, iron, nickel, or alloys
thereof) that was used to initially sinter the precursor diamond
particles that form the polycrystalline diamond or an infiltrant
used to re-infiltrate a preformed leached polycrystalline diamond
table. Other examples of methods for fabricating the superhard
raceway elements are disclosed in U.S. Pat. Nos. 7,866,418,
7,842,111; and 8,236,074, the disclosure of each of which is
incorporated herein, in its entirety, by this reference.
[0040] The diamond particles that may form the polycrystalline
diamond in the superhard table 134 may also exhibit a larger size
and at least one relatively smaller size. As used herein, the
phrases "relatively larger" and "relatively smaller" refer to
particle sizes (by any suitable method) that differ by at least a
factor of two (e.g., 30 .mu.m and 15 .mu.m). According to various
embodiments, the diamond particles may include a portion exhibiting
a relatively larger size (e.g., 40 .mu.m, 30 .mu.m, 20 .mu.m, 15
.mu.m, 12 .mu.m, 10 .mu.m, 8 .mu.m) and another portion exhibiting
at least one relatively smaller size (e.g., 6 .mu.m, 5 .mu.m, 4
.mu.m, 3 .mu.m, 2 .mu.m, 1 .mu.m, 0.5 .mu.m, less than 0.5 .mu.m,
0.1 .mu.m, less than 0.1 .mu.m). In an embodiment, the diamond
particles may include a portion exhibiting a relatively larger size
between about 10 .mu.m and about 40 .mu.m and another portion
exhibiting a relatively smaller size between about 1 .mu.m and
about 4 .mu.m. In some embodiments, the diamond particles may
comprise three or more different sizes (e.g., one relatively larger
size and two or more relatively smaller sizes), without limitation.
Upon HPHT sintering the diamond particles to form the
polycrystalline diamond, the polycrystalline diamond may, in some
cases, exhibit an average grain size that is the same or similar to
any of the diamond particles sizes and distributions discussed
above. Additionally, in any of the embodiments disclosed herein,
the superhard raceway elements 110 may be free-standing (e.g.,
substrateless) and formed from a polycrystalline diamond body that
is at least partially or fully leached to remove a metal-solvent
catalyst initially used to sinter the polycrystalline diamond body.
In an embodiment, the leached polycrystalline diamond body may be
formed to exhibit a porosity of about 1-10% by volume such that the
pores of the polycrystalline diamond body may be impregnated with
lubricant to assist in minimizing friction caused by contact of the
rolling elements 128 on the raceway. In other embodiments, the
polycrystalline diamond body may exhibit a selected porosity that
is higher or lower.
[0041] At least some of the superhard raceway elements 110 may
comprise a superhard table 134 including a convexly-curved raceway
surface 118 (i.e., curving to lie on an imaginary cylindrical
surface) as shown in FIGS. 1B and 1C. Each of the superhard tables
134 may be bonded to a corresponding substrate 136. Optionally, one
or more of the superhard raceway elements 110 may exhibit a
peripherally-extending edge chamfer and/or radius. However, in
other embodiments, the edge chamfer or radius may be omitted.
[0042] The superhard raceway elements 110 may have any suitable
individual shape. As best shown in FIG. 1D, each superhard raceway
element 110 may have a generally rounded rectangular-shaped body
including a pair of generally parallel side surfaces 110A, a first
end surface 110B, and a second end surface 110C. The side surfaces
110A may extend between the first end surface 110B and the second
end surface 110C and vice versa. In the illustrated embodiment,
both the first end surface 110B and the second end surface 110C may
have a generally convex curvature. In other embodiments, the
superhard raceway elements 110 may have a generally elliptical
shape, a generally wedge-like shape, a generally cylindrical shape,
or any other suitable body shape.
[0043] In an embodiment, the superhard raceway elements 110 may be
configured to help prevent the rolling elements 128 from lodging in
the gaps 132 and/or to maintain contact with the superhard raceway
elements 110 as the rolling elements 128 roll over the raceway
surfaces 118 during use. For example, at least one or both of side
surfaces 110A of the superhard raceway elements 110 may be oriented
at an oblique angle .theta. (shown in FIG. 1I) relative to the
rotation axis 114. In some embodiments, each of the superhard
raceway elements 110 may be substantially at the same general
oblique angle .theta. relative to the rotation axis 114, while in
other embodiments, the oblique angles .theta. may be different. In
an embodiment, the angle .theta. may be about 40 degrees to about
85 degrees; about 50 degrees to about 80 degrees; or about 55
degrees to about 75 degrees. In other embodiments, the angle
.theta. may be larger or smaller. The angle .theta. may be selected
such that only a portion of one of the rolling elements 128 extends
across one of the gaps 132 between two of the superhard raceway
elements 110 at any given time, while the rolling element 128
maintains contact with the two superhard raceway elements 110. Put
another way, the line of contact of the rolling element 110 and the
superhard raceway elements 110 may be misaligned related to the
extension of the gap in length. Thus, the rolling elements may
avoid becoming impeded by the gaps 132 during operation. Such a
configuration may provide a smoother ride on the raceway for the
rolling elements 128.
[0044] Referring again to FIGS. 1A and 1B, the outer race 104 may
exhibit a configuration similar to the inner race 102. For example,
the outer race 104 may include the support ring 120 and the
superhard raceway elements 122 mounted or otherwise attached to the
support ring 120 with recesses 117 formed in an inner surface of
the support ring 120. In the illustrated embodiment, the support
ring 120 may include an outer surface substantially parallel to the
inner surface. The recesses 117 may be configured to generally
correspond to the recesses 116 formed in the support ring 108 of
the inner race 102. The superhard raceway elements 122 may exhibit
any selected geometric shape. In some embodiments, the superhard
raceway elements 122 may have a generally rounded rectangular
shape, a cylindrical shape, a wedge-like shape, or any other
suitable geometric shape. Each of the superhard raceway elements
122 may include a concavely-curved raceway surface 124. The
superhard raceway elements 122 may be made from any of the
materials discussed above for the superhard raceway elements 110
and configured and positioned to form at least a portion of the
raceway for the rolling elements 128 to roll/run on. For example,
at least some of the superhard raceway elements 122 may comprise
superhard table 134 bonded to a corresponding substrate 136.
[0045] In an embodiment, rotation of the inner race 102 and/or the
outer race 104 may cause the rolling elements 128 to roll/run on
the raceway formed between the raceway surface 118 of the superhard
raceway elements 110 and the raceway surfaces 124 of the superhard
raceway elements 122. By forming the raceway with the superhard
raceway elements 110, 122, deformation of the support rings 108,
120 and or the risk of fatigue may be reduced because the rolling
elements 128 generally avoid contact with the support rings 108,
120. Moreover, fatigue at the contact surface between the superhard
raceway elements 110, 122 and the rolling elements 128 may be
reduced because superhard material does not deform as much as a
traditional raceway surface (i.e., steel) due to the superhard
raceway material's high modulus of elasticity. For example, in an
embodiment, the superhard table 134 may exhibit a modulus of
elasticity between about 800 GPa and about 1200 GPa (e.g., about
800 GPa to about 850 GPa, or about 841 GPa). In other embodiments,
the superhard table 134 may exhibit a selected modulus of
elasticity that is higher or lower. In an embodiment, the superhard
raceway elements 110, 122 may enhance the general load capacity of
the radial roller bearing apparatus 100. Further, the superhard
raceway elements 110, 122 may form a raceway that exhibits lower
friction and is more resistant to abrasion and corrosion than a
traditional raceway (i.e., steel). This may be particularly
advantageous for wind turbine gearbox applications where frequent
starts and stops are expected. Optionally, a relatively high
thermal conductivity of the superhard raceway elements 110, 122 may
also help reduce adhesive wear and resulting scuffing and
micropitting of the raceway and/or the rolling elements 128. For
example, the raceway (i.e., raceway surfaces 118, 124) may exhibit
a thermal conductivity of about 543 W/m-K which is about twelve
(12) times the thermal conductivity of steel. In other embodiments,
the raceway may exhibit a thermal conductivity of at least about
300 W/m-K; at least about 800 W/m-K; at least about 1300 W/m-K; or
about 2000 W/m-K. In addition, the raceway may exhibit a thermal
conductivity of about 300 W/m-K to about 2000 W/m-K; about 700
W/m-K to about 1600 W/m-K; or about 1000 W/m-K to about 1300 W/m-K.
In other embodiments, the thermal conductivity of the raceway may
be larger or smaller. Accordingly, heat generated by eventual
skidding and/or slipping of the rolling elements 128 on the raceway
may be quickly conducted away from the raceway to reduce adhesive
wear and resulting scuffing and/or micro-pitting. Because of the
raceway's large thermal conductivity, heat generated by eventual
skidding and slipping of the rolling elements 128 may be more
quickly conducted away from the contact surface between the rolling
elements 128 and the raceway. In other embodiments, the raceway
surfaces 118, 124 and/or the raceway may exhibit thermal
conductivities that are higher or lower.
[0046] As discussed above, the roller assembly 106 may include the
cage 126 and the rolling elements 128. The cage 126 may include a
plurality of cage pockets 130 formed in the cage 126 and
distributed circumferentially about the rotation axis 114. Each of
the cage pockets 130 may be configured to retain one of the rolling
elements 128. In the illustrated embodiments, each of the cage
pockets 130 may exhibit a substantially rectangular cross-sectional
shape. In other embodiments, one or more of the cage pockets 130
may exhibit a generally elliptical cross-sectional shape, a
generally circular cross-sectional shape, a generally square
cross-sectional shape, a generally trapezoidal cross-sectional
shape, or any other suitable cross-sectional shape. The cage
pockets 130 may be arranged in a single row about the rotation axis
114. In other embodiments, the cage pockets 130 may be arranged in
two rows, three rows, four rows, or any other number of rows. The
cage 126 may be made from any number of suitable materials. For
example, the cage 126 may comprise a metal, an alloy, an alloy
steel, carbon steel, stainless steel, brass, tungsten carbide, or
any other suitable material. The rolling elements 128 may be
rotatably mounted within the cage pockets 130, with each of the
rolling elements 128 having a longitudinal rotation axis
substantially parallel to the rotation axis 114.
[0047] FIGS. 1E and 1F are isometric and cross-sectional views,
respectively, of one of the rolling elements 128 removed from the
cage 126. The rolling element 128 may exhibit a generally
cylindrical body having a diameter D as well as an upper surface
128A and a lower surface 128B defining a length L extending
therebetween. In an embodiment, the upper surface 128A and the
lower surface 128B may be generally planar. In other embodiments,
the upper surface 128A and/or the lower surface 128B may be
generally curved, generally conical, combinations thereof, or may
have any other suitable configuration. Variations in the length L
and/or the diameter D of the one or more rolling elements 128 may
be configured to help resist fatigue and/or ultimate failure and/or
influence the rotational speed of the rolling elements 128. In
addition, the relationship between the length L of one or more of
the rolling elements 128 and the diameter D of the one or more
rolling elements 128 may be configured to provide a selected
contact area with the raceway use, help resist fatigue, damage,
and/or ultimate failure. For example, the diameter D of at least
one of the rolling elements 128 may be at least: about ten percent
(10%); about twenty percent (20%); about thirty percent (30%);
about forty percent (40%); about fifty percent (50%); about sixty
percent (60%); about seventy percent (70%); about eighty percent
(80%); about ninety percent (90%); about one hundred percent
(100%); or about one hundred and ten percent (110%) of the length L
of at least one of the rolling elements 128. In addition, the
diameter D of at least one of the rolling elements 128 may be about
ten percent (10%) to about two hundred percent (200%); or about one
hundred percent (100%) of the length L of at least one of the
rolling elements 128. In other configurations, the rolling elements
128 may exhibit a generally spherical body, a generally conical
body, a generally hourglass-like body, or any other suitable
geometric shape.
[0048] In an embodiment, the rolling elements 128 (or any of the
rolling elements disclosed herein) may at least partially comprise
one or more superelastic materials. For example, typical
superelastic materials exhibit non-linear elastic deformation
during use. Non-linear elastic deformation is elastic deformation
characterized by a non-linear relationship between stress and
strain. Examples of suitable superelastic materials include, but
are not limited to, nickel-titanium alloys (e.g., nitinol or
SM-100.TM. which is a more wear resistant nitinol-type alloy),
copper-aluminum-nickel alloys, copper-tin alloys, copper-zinc
alloys, iron-manganese-silicon alloys, combinations thereof, or any
other suitable superelastic material. Consequently, the rolling
elements 128 may exhibit a larger elastic resilience than rolling
elements formed of other materials (i.e. steel) such that the
rolling elements 128 may help enhance fatigue life of the radial
roller bearing apparatus 100. In the illustrated embodiment, the
rolling element 128 may be substantially formed of a single
superelastic material as shown in FIG. 1F. As shown in FIG. 1G, in
other embodiments, the rolling element 128 may include at least an
inner core 129A surrounded by an outer layer and/or coating 129B
made from any of the superelastic material disclosed herein. The
inner core 129A may comprise carbon steel, stainless steel, alloy
steel, tungsten carbide, or another suitable material. In other
embodiments, the rolling element 128 may include two, three, four,
or any suitable number of layers, portions, or coatings of
superelastic materials. In other embodiments, the rolling element
128 may include a portion including one or more superelastic
materials and another portion not including superelastic materials.
In yet other embodiments, the rolling element 128 may not include
superelastic materials and/or may include one or more metallic
and/or non-superabrasive materials. In other embodiments, as shown
in FIG. 1H, one or more of the rolling elements 128 may comprise an
outer shell 129B at least partially defining a hollow interior
space extending at least partially through the rolling element 128.
For example, in an embodiment, one or more of the rolling elements
128 may comprise a generally cylindrical PCD body with the inner
core removed to form the outer shell 129B. The outer shell 129B may
comprise a superelastic material, PCD, or another suitable
material. Such a configuration may help provide flexibility and/or
abrasion resistance to the rolling element 128. In other
embodiments, such a configuration may help lower the inertia of the
rolling element 128.
[0049] FIG. 1J is a partial cross-sectional view of one of the
rolling elements 128 running on a portion of the raceway formed by
the superhard raceway elements 122 of the outer race 104. As shown,
the raceway and/or the rolling elements 128 may also be configured
such that the portion of one or more of the rolling elements 128 in
contact with the raceway elastically deforms to provide a selected
contact area during use. Elastic deformation is a change in shape
of a material at a stress that is recoverable after the stress is
removed. For example, one or more of the rolling elements 128 may
exhibit a modulus of elasticity of about 20 GPa to about 109 GPa.
As another example, common superelastic nickel-titanium alloys
(e.g., nitinol) from which one or more of the rolling elements 128
may be made have an elastic modulus of about 70 GPa to about 85 GPa
in the austenite phase and an elastic modulus of about 28 GPa to
about 41 GPa in the stress-induced martensite phase. Thus, in some
embodiments, the nickel-titanium alloy may exhibit a martensite
deformation temperature ("M.sub.d") that is sufficiently high so
that stress-induced martensite is generated during loading and
operation of the roller bearing apparatus 100 in order to rely on
the relatively low elastic modulus of the stress-induced martensite
phase. For example, M.sub.d of the superelastic nickel-titanium
alloys used herein may be about 100.degree. C. to about 300.degree.
C., such as 150.degree. C. to about 200.degree. C. or about
100.degree. C. to about 145.degree. C. In other embodiments, one or
more of the rolling elements 128 may exhibit a modulus of
elasticity of about 60 GPa to about 90 GPa.
[0050] Various embodiments also contemplate that the raceway may
exhibit a modulus of elasticity that exceeds a modulus of
elasticity of one or more of the rolling elements. For example, the
modulus of elasticity of the raceway may be at least: about forty
(40) times greater, about thirty (30) times greater, about twenty
(20) times greater, about fifteen (15) times greater; about twelve
(12) times greater; about nine (9) times greater; about six (6)
times greater; or about three (3) times greater than a modulus of
elasticity of one or more of the rolling elements 128. In addition,
the modulus of elasticity of raceway may be at least: about three
(3) times greater to about fifty (50) times greater; about five (5)
times greater to about fifty (50) times greater, about thirty (30)
times greater to about forty five (45) times greater, about twenty
(20) times greater to about forty five (45) times greater, about
seven (7) times greater to about sixteen (16) times greater; or
about four (4) times greater to about fourteen (14) times greater
than the modulus of elasticity of one or more of the rolling
elements 128. The difference between the modulus of elasticity of
the rolling elements 128 and the raceway may enhance resistance of
the radial roller bearing apparatus 100 to shock and/or vibration
loading. In other configurations, the modulus of elasticity of one
or more of the rolling elements 128 and the modulus of elasticity
of the raceway may be larger or smaller relative to each other.
Such a configuration may enhance resistance of the radial roller
bearing apparatus 100 to shock and vibration loading. Moreover, in
other embodiments, the roller elements 128 and the superhard
raceway elements 110, 122 may include different materials such that
common failure modes such as welding, galling, and/or scuffing may
be reduced. Thus, by varying the material design of the rolling
elements 128 and/or the superhard raceway elements 110, 122, the
rolling elements 128 and/or the superhard raceway elements 110, 122
may be configured to enhance the bearing life of the radial roller
bearing apparatus 100 in one or more different ways.
[0051] In an embodiment, the roller elements 128 and the raceway
may be configured to influence elastohydrodynamic lubrication
and/or elastohydrodynamic fluid film formation. For example, where
the loading conditions, modulus of elasticity of the raceway,
modulus of elasticity of the rolling elements 128, the rotational
speed of the rotor, or combinations thereof is sufficient, an
elastohydrodynamic fluid film may develop between the raceway and
the rolling elements 128. The portion of the rolling elements 128
in contact with the raceway (i.e., raceway surfaces 118 and/or 124)
may elastically deform such that the rolling elements 128 exhibit a
greater contact area with the raceway to generate or facilitate
fluid formation between the rolling elements 128 and adjacent
superhard raceway elements 110 and/or superhard raceway elements
122. In an embodiment, the difference between the modulus of
elasticity of the rolling elements 128 and the raceway may help
change the geometry and/or nature of contact between the rolling
elements 128 and the raceway. For example, a larger deformation of
the rolling elements 128 may help form a broader area of contact
between the rolling elements 128 and the raceway and also a broader
area in which elastohydrodynamic lubrication and/or
elastohydrodynamic fluid film formation may occur. Such a
configuration may help promote effective elastohydrodynamic
lubrication and/or elastohydrodynamic fluid film formation at lower
speeds. Consequently, the rolling elements 128 may be configured to
help form a fluid film having sufficient pressure and at
appropriate loading conditions, and/or to prevent or limit physical
contact between the respective raceway and the rolling elements 128
to thereby reduce wear of the superhard raceway elements 110, 122
and/or the rolling elements 128. In such a situation, the radial
roller bearing apparatus 100 may be described as operating
hydrodynamically. When the rotational speed of the rotor is
reduced, the pressure of the fluid film may not be sufficient to
prevent the rolling elements 128 and the raceway from contacting
each other. Thus, by selecting the modulus of elasticity of the
rolling elements 128 and the raceway, the radial roller bearing
apparatus 100 may be configured to exhibit a desired amount of
elastohydrodynamic lubrication and/or fluid film formation during
certain operating conditions.
[0052] In other embodiments, the radial roller bearing apparatus
may include a cageless roller assembly. For example, FIG. 2A is an
exploded isometric view of an embodiment of a radial roller bearing
apparatus 200A. The principles of the radial roller bearing
apparatus 200A may be employed with any of the embodiments
described with relation to FIGS. 1A through 1J and vice versa. In
the radial roller bearing apparatus 200A, a plurality of elongated
rolling elements 228A are circumferentially distributed about a
rotation axis 214A and interposed between an inner race 202A having
superhard raceway elements 210A and an outer race 204A having
superhard raceway elements 222A. As shown, a roller assembly 206A
may include the rolling elements 228A positioned between the inner
race 202A and the outer race 204A without a cage to separate the
rolling elements 228A. Thus, each of the rolling elements 228A may
push against other rolling elements 228A to hold the rolling
elements 228A in place. The rolling elements 228A may be positioned
configured such that the rolling elements may rotate therebetween,
with each of the elongated rolling elements 228A having a
longitudinal axis substantially parallel to the rotation axis 214A.
Optionally, the inner race 202A and/or the outer race 204A may
include flange features 242A configured to help maintain the
position of rolling elements 228A between the inner race 202A and
the outer race 204A. Moreover, the rolling elements 228A may be
made from any of the materials discussed above for the rolling
elements 128.
[0053] FIG. 2B is an exploded isometric view of another embodiment
of a cageless radial roller bearing apparatus 200B. The principles
of the radial roller bearing apparatus 200A may be employed with
any of the embodiments described with relation to FIGS. 1A through
2A and vice versa. In the radial roller bearing apparatus 200B, a
plurality of generally spherical rolling elements 228B are
circumferentially distributed about a rotation axis 214B and
interposed between an inner race 202B having superhard raceway
elements 210B and an outer race 204B having superhard raceway
elements 222B. Like radial roller bearing apparatus 200A, a roller
assembly 206B may include the rolling elements 228B positioned
between the inner race 202B and the outer race 204B without a cage
to separate the spherical rolling elements 228B. Thus, each of the
rolling elements 228B may help hold one another in place.
Optionally, the inner race 202B and/or the outer race 204B may
include flange features 242B configured to help maintain the
position of the rolling elements 228B between the inner race 202B
and the outer race 204B. Moreover, the rolling elements 228B may be
made from any of the materials discussed above for the rolling
elements 128.
[0054] In yet other embodiments, the radial roller bearing
apparatus may include a plurality of rows of rolling elements
and/or superhard raceway elements. For example. FIG. 3 is an
isometric cutaway view of a radial roller bearing apparatus 300.
The radial roller bearing apparatus 300 has many of the same
components and features that are included in the radial roller
bearing apparatuses 100 and 200 of FIGS. 1A-2B. Therefore, in the
interest of brevity, the components and features of the radial
roller bearing apparatuses 100 and 300 that correspond to each
other have been provided with identical reference numerals, and an
explanation thereof will not be repeated. However, it should be
noted that the principles of the radial roller bearing apparatus
300 may be employed with any of the embodiments described with
respect to FIGS. 1A through 2B.
[0055] In the radial roller bearing apparatus 300, a roller
assembly 306 may be interposed between an inner race 302 and an
outer race 304 and may include a cage 326 and a plurality of
rolling elements 328. The cage 326 of the roller assembly 306 may
include a plurality of cage pockets 330 formed in the cage 326 and
distributed circumferentially about a rotation axis (not shown) in
two rows. Each of the cage pockets 330 may be configured to retain
one of the rolling elements 328. Similar to the cage pockets 130,
each of the cage pockets 330 may exhibit a substantially
rectangular cross-sectional shape. In other embodiments, one or
more of the cage pockets 330 may exhibit a generally elliptical
cross-sectional shape, a generally circular cross-sectional shape,
a generally square cross-sectional shape, a generally trapezoidal
cross-sectional shape, or any other suitable cross-sectional shape.
The rolling elements 328 may be rotatably mounted within the cage
pockets 330, with each of the rolling elements 328 having a
longitudinal rotation axis substantially parallel to the rotation
axis 314. Similar to the superhard raceway elements 110, 120, the
inner race 302 may include superhard raceway elements 310 and the
outer race 304 may include superhard raceway elements 322, both
configured and positioned to at least partially define a raceway
for the rolling elements 328. In the illustrated embodiment, the
superhard raceway elements 310 and/or 322 may be sized and
distributed about the rotation axis 314 to at least partially
define two raceways, one for each row of rolling elements 328. In
other embodiments, the superhard raceway elements 310 and/or 322
may be sized and distributed about the rotation axis 314 to at
least partially define a single raceway for both of the two rows of
rolling elements 328. Optionally, as illustrated, the inner race
302 and/or the outer race 304 may include flange features 342
configured to help maintain the rolling elements 328 between the
inner race 302 and the outer race 304.
[0056] Superhard raceway elements 310 and/or 322 may include any of
the materials discussed above for the superhard raceway elements
110. For example, at some of the superhard raceway elements 310
and/or 322 may include a superhard material such as a PCD.
Moreover, the rolling elements 328 may be made from any of the
materials discussed above for the rolling elements 128. For
example, one or more of the rolling elements 328 may include one or
more superelastic materials (e.g., nickel-titanium alloys). In
addition, the cage 326 may be made from any of the materials
discussed above for the cage 126. For example, cage 326 may
comprise a metal, an alloy, an alloy steel, carbon steel, stainless
steel, brass, tungsten carbide, or any other suitable material.
[0057] In an embodiment, the material design of the superhard
raceway elements 310, 322 and/or the rolling elements 328 may be
configured to influence the operational life and/or performance of
the radial roller bearing apparatus 300. For example, by forming
the raceway with the superhard raceway elements 310, 322 including
one or more superhard materials, fatigue at the contact surface
between the superhard raceway elements 310, 322 and the rolling
elements 328 may be reduced because superhard material will not
deform as much as a traditional raceway surface (i.e., steel) due
to the superhard raceway material's high modulus of elasticity. In
other embodiments, the superhard bearing elements 310 and/or 322 or
raceway may be configured to exhibit a modulus of elasticity that
exceeds a modulus of elasticity of one or more of the rolling
elements 328 such that resistance of the radial roller bearing
apparatus 300 to shock, vibration loading, and/or common failure
modes such as welding, galling, and/or scuffing may be
enhanced.
[0058] While the roller assembly 306 is illustrated including two
rows of cage pockets 330 and/or rolling elements 328, the roller
assembly 306 may include three, four, five, or any other suitable
number of rows of cage pockets 330 and/or rolling elements 328.
Moreover, while each of the rows of cage pockets 330 and/or rolling
elements 328 are illustrated exhibiting similar configurations, in
other embodiments, the configuration of each row may vary. For
example, the roller assembly 306 may include a first row of cage
pockets 330 and/or rolling elements 328 that are physically larger
(e.g., radius and/or length) than a second row of cage pockets 330
and/or rolling elements 328. In addition, while two rows are
superhard raceway elements 310 and 322 are illustrated, in other
embodiments, the inner race 302 and/or the outer race 304 may
include one row, three rows, four rows, or any suitable number of
rows of superhard raceway elements.
[0059] Embodiments of the invention contemplate that the concepts
used in the radial roller bearing apparatuses described above may
also be employed in a variety of different bearings including, but
not limited to, thrust roller bearings, spherical roller bearings,
tapered roller bearings, angular contact bearings, ball bearings,
linear motion bearings, combinations thereof, or any other suitable
type of bearing. For example, FIG. 4 is an exploded isometric view
of a tapered roller bearing apparatus 400 according to an
embodiment. It should be noted that the principles of the tapered
roller bearing apparatus 400 may be employed with any of the
embodiments described with respect to FIGS. 1A through 3 and vice
versa.
[0060] The tapered roller bearing apparatus 400 may include an
inner race 402, an outer race 404, and a roller assembly 406. The
inner race 402 may include a support ring 408 and a plurality of
superhard raceway elements 410. The outer race 404 may include a
support ring 418 and a plurality of superhard raceway elements 422.
In an embodiment, the support ring 408 may be configured as a cone
and the support ring 418 may be configured as a cup. For example,
the support ring 418 may extend about and receive the support ring
408. The inner surface 408A of the support ring 408 may be
substantially incongruent relative to the outer surface 408B (into
which the superhard raceway elements 410 are positioned) of the
support ring 408 and substantially congruent relative to the outer
surface 418B of the support ring 418. The outer surface 418B of
support ring 418 may be curved to lie substantially on an imaginary
cylindrical surface. Further, the inner surface 418A (into which
the superhard raceway elements 422 are positioned) of the support
ring 418 may be substantially incongruent relative to the outer
surface 418B of the support ring 418 and substantially congruent
relative to the curved outer surface 408B of the support ring
408.
[0061] As shown, the roller assembly 406 may be interposed between
the inner race 402 and the outer race 404. The roller assembly 406
may include a cage 426 and a plurality of generally cylindrical
rolling elements 428. In an embodiment, the support ring 408 and/or
the support ring 418 may include respective flange features (not
shown) configured to help maintain the rolling elements 428 between
the inner race 402 and the outer race 404. In other embodiments,
the flange features may be omitted from both the support ring 408
and the support ring 418.
[0062] In an embodiment, the superhard raceway elements 410 of the
inner race 402 and the superhard raceway elements 422 of the outer
race 404 may be positioned and configured to at least partially
define a raceway for the rolling elements 428 to run over or roll
on during use. For example, the superhard raceway elements 410 may
be positioned and configured to form a portion of the raceway on
the outer surface 408B of the support ring 408 curved to lie
substantially on an imaginary conical surface. Similarly, the
superhard raceway elements 422 may be positioned and configured on
the inner surface 418A of the support ring 418 to form another
portion of the raceway curved to lie substantially on an imaginary
conical surface.
[0063] In an embodiment, the cage 426, including the rolling
elements 428, may form at least a portion of a cone (e.g., a
frustoconical ring) and may be configured to be interposed between
the conical inner surface 418A of the support ring 418 and the
conical outer surface 408B of the support ring 408. When the
tapered roller bearing apparatus 400 is loaded with an external
force (e.g., wind load), the conical geometric relationship of
inner surface 418A and the outer surface 408B may transform the
external force into separate load components. Such a configuration
may allow the thrust roller bearing apparatus 400 to support both
radial and axial loads. In addition, the conical geometric
relationship and/or curvature of the raceway may help allow for
some degree of shaft misalignment and/or deflection during
operation.
[0064] While the raceway is shown including one or more portions
curved to lie substantially on an imaginary conical surface, one or
more portions of the raceway may be curved to lie substantially on
an imaginary spherical surface or another curved surface. Moreover,
while generally cylindrical rolling elements 428 are illustrated,
in other embodiments, the cage 426 may include one or more tapered
rolling elements 428, one or more generally spherical rolling
elements 428 (e.g., a crowned (barrel) type shape), and/or one or
more rolling elements 428 having other suitable geometric
shapes.
[0065] Superhard raceway elements 410 and/or 422 may include any of
the materials discussed above for the superhard raceway elements
110. For example, at least some of the superhard raceway elements
410 and/or 422 may include a PCD table. In addition, the rolling
elements 428 may be made from any of the materials discussed above
for the rolling elements 128. For example, one or more of the
rolling elements 428 may include one or more superelastic materials
(e.g., nickel titanium alloys) and/or steel. The cage 426 may also
be made from any of the materials discussed above for the cage 126.
For example, cage 426 may comprise a metal, an alloy, an alloy
steel, carbon steel, stainless steel, brass, tungsten carbide, or
any other suitable material. In an embodiment, the material design
of the superhard raceways elements 410, 422 and/or the rolling
elements 428 may be configured to influence the operational life
and/or performance of the tapered roller bearing apparatus 400. For
example, by forming the raceway with the superhard raceway elements
410, 422 including one or more selected superhard materials,
fatigue at the contact surface between the superhard raceway
elements 410, 422 and the rolling elements 428 may be reduced
because superhard material will not deform as much as a traditional
raceway surface (i.e., steel). This is in part due to the superhard
raceway material's high modulus of elasticity.
[0066] FIG. 5 is a partial cutaway view of an angular contact ball
bearing apparatus 900 according to an embodiment. It should be
noted that the principles of the angular contact ball bearing
apparatus 900 may be employed with any of the embodiments described
with respect to FIGS. 1A through 4 and vice versa. The angular
contact ball bearing apparatus 900 may include an inner race 902,
an outer race 904, and a roller assembly 906. The inner race 902
may include a support ring 908 having an inner shoulder 908A and an
upper shoulder 908B and a plurality of superhard raceway elements
910. The outer race 904 may include a support ring 918 having an
outer shoulder 918C and a lower shoulder 918D and a plurality of
superhard raceway elements 922. The support ring 918 of the outer
race 904 may extend about and receive the support ring 908 of the
inner race 902.
[0067] In an embodiment, superhard raceway elements 922 may be
positioned between outer shoulder 918C and lower shoulder 918D on
an inner surface of support ring 918. Each of the superhard raceway
elements 922 may be partially disposed in a corresponding recess
formed in the inner surface of support ring 918 and secured
partially therein via brazing, press-fitting, threadly attaching,
fastening with a fastener, combination of the foregoing, or another
suitable technique. In other embodiments, each of the superhard
raceway elements 922 may be partially disposed in a common slot for
all of the superhard raceway elements 922 formed in the support
ring 918. Superhard raceway elements 922 may be configured to at
least partially define a raceway curved to lie substantially on an
imaginary spherical surface.
[0068] In addition, superhard raceway elements 910 may be
positioned between inner shoulder 908A and upper shoulder 908D on
an inner surface of support ring 908. Each of the superhard raceway
elements 910 may be partially disposed in a corresponding recess
formed in the inner surface of support ring 908 and secured
partially therein via brazing, press-fitting, threadly attaching,
fastening with a fastener, combination of the foregoing, or another
suitable technique. In other embodiments, each of the superhard
raceway elements 910 may be partially disposed in a common slot for
all of the superhard raceway elements 910 formed in the support
ring 908. Superhard raceway elements 910 may be configured to form
at least a portion of a raceway curved to lie substantially on an
imaginary spherical surface.
[0069] As shown in FIG. 5, in an embodiment, roller assembly 906
may comprise a plurality of generally spherical rolling elements
928 configured to roll or run on the raceway between the inner race
902 and outer race 904. Such a configuration provides the ability
to support both thrust and radial loads. In an embodiment, the
geometry of angular contact ball bearing apparatus 900 may be
selected to influence operation of angular contact ball bearing
apparatus 900. For example, the capacity of angular contact ball
bearing apparatus 900 to support thrust loads may increase by
increasing a contact angle .alpha.. The contact angle .alpha. is
the angle between a line joining points of contact of the rolling
element 928 and the portions of the raceway, along which the load
is transmitted from one raceway to another, and a line generally
perpendicular to the axis 914. In addition, due to displacement
between the portions of the raceway formed on the support rings
908, 918 and/or the curvature of the raceway, angular contact ball
bearing apparatus 900 may allow for some degree of shaft
misalignment or deflection during operation. Such a configuration
may allow angular contact ball bearing apparatus 900 to tolerate
burst of wind and/or other high impact loads that may be present
during operation of wind turbine systems or other systems.
[0070] Superhard raceway element 910 and/or 922 may include any of
the materials discussed above in relation to superhard bearing
elements 110 (e.g., superhard materials). In addition, rolling
elements 928 may include any of the materials discussed in relation
to rolling elements 128 (e.g., superelastic materials). Like the
other roller bearing apparatuses, the material design of the
superhard raceway elements 910, 922, and/or rolling elements 928
may be configured to influence the operational life and/or
performance of angular contact ball bearing apparatus 900. For
example superhard raceway elements 910, 922 may be configured to
exhibit a modulus of elasticity that exceeds a modulus of
elasticity of one or more of the rolling elements 928 such that
resistance of the angular contact ball bearing apparatus 900 to
shock, vibration loading, and/or common failure modes such as
welding, galling, and/or scuffing may be enhanced.
[0071] The roller bearing apparatuses described herein may be
employed in a variety of mechanical applications. For example,
pumps, turbines, gear boxes or transmissions may benefit from a
roller bearing apparatus disclosed herein. FIG. 6 is a partial
isometric cutaway view of a wind turbine system 500 according to an
embodiment. The system 500 may include a housing 544 and a main
gear shaft 546 operably connected to a wind turbine, i.e., blades
attached to a hub, (not shown). A pair of tapered roller bearing
apparatuses 550 may be operably connected to the main shaft 546. In
an embodiment, each of the tapered roller bearing apparatus 550 may
be configured similar to tapered roller bearing apparatus 400. For
example, each tapered roller bearing apparatus 550 may include an
inner race 502 (i.e., rotor), an outer race 504 (i.e., stator), and
a roller assembly 506. The shaft 546 may extend through the inner
races 502 and may be secured to each inner race 502 by press
fitting or otherwise attaching the gear shaft 546 to the inner race
502, threadly coupling the shaft 546 to the inner race 502, or
another suitable technique.
[0072] In an embodiment, the roller assembly 506 may be interposed
between the inner race 502 and the outer race 504. The roller
assembly 506 may include a cage 526 having a plurality of cage
pockets (not shown) for retaining a plurality of rolling elements
528. The cage 526, including the rolling elements 528, may form at
least a portion of a cone (e.g., frustoconical ring). In an
embodiment, the rolling elements 528 may exhibit a generally
cylindrical geometric shape and may be rotatably mounted within the
cage pockets. In other embodiments, at least one of the rolling
elements 528 may exhibit a generally spherical geometric shape, a
generally conical shape, or any other suitable geometric shape. The
rolling elements 528 may include any of the materials discussed
above for the rolling elements 128. For example, one or more of the
rolling elements 528 may include one or more superelastic materials
such that the portion of the rolling elements 528 in contact with
the raceway exhibit non-linear elastic deformation and generally
conform to the raceway during use. Such a configuration may help
reduce stresses experienced by and/or failure of (e.g., flaking,
strain, pitting, or combinations thereof) the rolling elements, the
superhard raceway elements, and/or the support rings.
[0073] In an embodiment, the inner race 502 may include a support
ring 508 and a plurality of superhard raceway elements 510 mounted
or otherwise attached to the support ring 508. Each of the
superhard raceway elements 510 may include a convexly-curved
raceway surface 518. As illustrated, the superhard raceway elements
510 may be configured and located to provide a raceway for the
rolling elements 528 to roll over/run on. In an embodiment, the
superhard raceway elements 510 may be located on the support ring
508 such that gaps 532 or other offsets are formed between adjacent
ones of the superhard raceway elements 510. A width of one or more
of the gaps 532 or an average width of the gaps 532 may be about
0.00020 inches (0.00508 mm) to about 0.100 inches (2.54 mm), and
more particularly about 0.00020 inches (0.00508 mm) to about 0.020
inches (0.508 mm). In other embodiments, one or more of the gaps
132 may exhibit larger or smaller widths. Optionally, one or more
of the gaps 532 may exhibit a relatively small width configured to
help limit lubricating fluid from being able to leak between
adjacent superhard raceway elements 510. For example, the superhard
raceway elements 510 may be located on the support ring 508 such
that the superhard raceway elements 510 are immediately adjacent to
one another to form a closely spaced plurality of the superhard
raceway elements 510 at least partially defining the raceway. In
other embodiments, the superhard raceway elements 510 may be
located on the support ring 508 such that the superhard raceway
elements 510 form a substantially contiguous superhard raceway. In
other embodiments, one or more of the gaps 532 may exhibit a
relatively large width configured to improve heat transfer. Thus,
by varying the configuration and size of the gaps 532, the gaps 532
may be optionally configured to impart a desired amount of heat
transfer and/or hydrodynamic film formation on the raceway during
operation. While the inner race 502 is shown having one row of the
superhard raceway elements 510, the inner race 502 may include two
rows, three rows, or any suitable number of rows of the superhard
raceway elements 510.
[0074] In an embodiment, the outer race 504 may extend about and
receive the inner race 502 and the roller assembly 506. The outer
race 504 may include a support ring 520 and a plurality of
superhard raceway elements 522 mounted or otherwise attached to the
support ring 520. Each of the superhard raceway elements 522 may
include a concavely-curved raceway surface 524. Like the superhard
raceway elements 510, the superhard raceway elements 522 may be
configured to at least partially define the raceway for the rolling
elements 528 to roll over or run on. While the outer race 504 is
shown including one row of the superhard raceway elements 522, the
outer race 504 may include two rows, three rows, or any number of
suitable rows of the superhard raceway elements 522.
[0075] The terms "rotor" and "stator" refer to rotating and
stationary components of the tapered roller bearing apparatuses
550. Thus, if the outer race 504 is configured to remain
stationary, the outer race 504 may be referred to as the stator and
the inner race 502 may be referred to as the rotor (or vice versa).
Moreover, while the thrust roller bearing apparatuses 550 are
illustrated as being similarly configured, the roller bearing
apparatuses 550 may have different configurations. For example, one
of the thrust roller bearing apparatuses 550 may be configured
similar to the thrust roller bearing apparatus 400 and the other
roller bearing apparatus 550 may be configured as an angular
contact bearing.
[0076] In an embodiment, wind may turn the blades on the wind
turbine (not shown), which in turn may rotate the main shaft 546
about a rotation axis 514. The main shaft 546 may rotate the inner
race 502 about the rotation axis 514, which, in turn, may cause the
rolling elements 528 to roll or run on the superhard raceway
elements 510 and the superhard raceway elements 522. Similar to
thrust bearing apparatus 400, the cone and cup design of the inner
race 502 and the outer race 504 may help the tapered roller bearing
apparatuses 550 tolerate at least some amount of axial and/or
radial misalignment and/or deflection between the inner race 502
and the outer race 504. As shown, the main shaft 546 may go through
a gear transmission box 511. For example, the main shaft 546 may be
connected to a first gear 511A that turns a second gear 511B or
vice versa. The first gear 511A may be larger than the second gear
511B. The second smaller gear 511B may be connected to a shaft 547
that turns a generator (not shown) to produce electricity.
[0077] As wind speed increases and energy builds within the system
500, the high thermal conductivity of the superhard raceway
elements 510, 522 may help remove heat from the contact surface
between the rolling elements 528 and the superhard raceway
elements. Such a configuration may help reduce the likelihood of
temperature induced strength reductions and/or failure in the
radial bearing apparatuses 550. Further, when the raceway surfaces
518, 524 are subjected to vibration under load with minimal rolling
movement, the high modulus contrast between the rolling elements
528 and the raceway may help provide resistance to shock and
vibration loading. Such a configuration may help reduce the
likelihood of fretting, micro pitting, and/or other types of wear
in the radial bearing apparatuses 550. This is particularly
advantageous given the frequent starts and stops of the system 500.
Moreover, in an embodiment, differences between the elasticity of
superhard materials forming raceway and the selected materials of
the rolling elements 528 may help reduce the likelihood of
adhesion.
[0078] FIG. 7 is an isometric cutaway view of a thrust bearing
roller bearing apparatus 600 according to an embodiment. The thrust
roller bearing apparatus 600 may include a stator 602, a roller
assembly 606, and a rotor 604. The roller assembly 606 may be
interposed between the stator 602 and the rotor 604. The roller
assembly 606 may optionally include a cage 626 having a plurality
of cage pockets 630 formed in the cage 626 for retaining a
plurality of rolling elements 628. Each of the cage pockets 630 may
exhibit a substantially rectangular geometric shape and may be
distributed circumferentially about a thrust axis 614 along which a
thrust force may be generally directed during use. In other
embodiments, the cage pockets 630 may exhibit a generally oval, a
generally circular, or any other suitable geometric shape. The cage
pockets 630 may be arranged in a single row about the thrust axis
614. In other embodiments, the cage pockets 630 may be arranged in
two rows, three rows, or any suitable number of rows. The cage 626
may be made from a variety of different materials including carbon
steel, stainless steel, cemented tungsten carbide, and the
like.
[0079] The rolling elements 628 may be rotatably mounted within the
cage pockets 630 and may be positioned substantially perpendicular
to the thrust axis 614. As illustrated, the rolling elements 628
may be generally cylindrical. In other embodiments, the rolling
elements 628 may be generally spherical or other suitable geometric
shapes. One or more of the rolling elements 628 may be formed from
any of the materials discussed above for the rolling elements 128.
For example, the rolling elements 628 may include one or more
superelastic materials such that the rolling elements 628 exhibit
non-linear elastic deformation and generally conform to the raceway
during use.
[0080] The stator 602 may include a support ring 608 defining an
opening 612 through which a shaft may extend. The support ring 608
may be made from a variety of different materials such as carbon
steel, stainless steel, tungsten carbide, combinations thereof, or
another suitable material. The stator 602 may further include a
plurality of superhard raceway elements 610 and a plurality of
interconnected recesses 616 formed in the support ring 608. Each of
the superhard raceway elements 610 may be partially disposed in a
corresponding one of the recesses 616 via brazing, press-fitting,
or another suitable technique. In another embodiment, each of the
superhard raceway elements 610 may be partially disposed in a
common slot for all of the superhard raceway elements 610 formed in
the support ring 608.
[0081] The superhard raceway elements 610 are illustrated being
distributed circumferentially about the thrust axis 614. In the
illustrated embodiment, each of the superhard raceway elements 610
may comprise a superhard table 634 including a raceway surface 618,
with the superhard table 634 bonded to a substrate 636. However, in
other embodiments, all or some of the superhard raceway elements
610 may be different or even substrateless. In an embodiment, the
raceway surfaces 618 may be substantially coplanar to one another.
The superhard raceway elements 610 may each be made from any of the
materials discussed above for the superhard raceway elements 110.
For example, the superhard raceway elements 610 may be made from
polycrystalline diamond or any other suitable superhard materials.
As shown, the superhard raceway elements 610 may exhibit a
geometric shape that is generally formed by the intersection of two
cylinders. In other embodiments, the superhard raceway elements 610
may exhibit a generally oval geometric shape, a generally
rectangular geometric shape, a wedge-like shape, or any other
suitable geometric shape.
[0082] The superhard raceway elements 610 may be circumferentially
distributed about the thrust axis 614 such that gaps between
adjacent ones of the superhard raceway elements 610 are occupied by
a portion of the support ring 608. Such a configuration may
increase the surface area of the support ring 608 in contact with
the superhard raceway elements 610 to help affix the superhard
raceway elements 610 to the support ring 608. In other embodiments,
the superhard raceway elements 610 may be circumferentially
distributed about the thrust axis 614 such that the superhard
raceway elements 610 generally abut one another.
[0083] In an embodiment, the superhard raceway elements 610 may be
configured and located on the support ring 608 to at least
partially define a raceway for the rolling elements 628 to roll
over or run on. By forming the raceway with the superhard raceway
elements 610 and forming the rolling elements 628 with one or more
materials having a lower elasticity (e.g., superelastic materials),
deformation of the support ring 608 and/or risk of fatigue and
eventual failure may be reduced. In addition, the configuration of
the superhard raceway elements 610 and the rolling elements 628 may
enhance the general load capacity of the thrust roller bearing
apparatus 600 and/or reduce friction.
[0084] The rotor 604 may be configured similar to the stator 602.
For example, the rotor 604 may include a support ring 620 and a
plurality of superhard raceway elements 622 mounted or otherwise
attached to the support ring 620, with each of the superhard
raceway elements 622 having a raceway surface 624. Like the
superhard raceway elements 610, the superhard raceway elements 622
may be configured and positioned on the support ring 620 to at
least partially define the raceway for the rolling elements 628 to
run over or roll on during use of the thrust roller bearing
apparatus 600. In an embodiment, the support ring 608 and/or the
support ring 620 may include a flange 642 configured to help
maintain the rolling elements 628 between the stator 602 and the
rotor 604. In other embodiments, the flange 642 may be omitted.
[0085] It is noted that in other embodiments, the disclosed thrust
roller bearing apparatuses may be used in a number of applications,
such as subterranean drilling systems, directional drilling
systems, pumps, transmissions, gear boxes, and many other
applications.
[0086] FIG. 8 is an exploded isometric view of a tapered thrust
roller bearing apparatus 700 according to another embodiment. The
tapered thrust roller bearing apparatus 700 may include a stator
702, a roller assembly 706, and a rotor 704. The roller assembly
706 may be interposed between the stator 702 and the rotor 704. The
roller assembly 706 may optionally include a cage 726 having a
plurality of cage pockets 730 formed in the cage 726 configured to
retain a plurality of rolling elements 728. Each of the cage
pockets 730 may have a substantially trapezoidal shape and may be
distributed circumferentially about a thrust axis 714. The cage 726
may be made from one or more selected materials, such as carbon
steel, stainless steel, tungsten, carbide material, combinations
thereof, or any other suitable material. The rolling elements 728
may be rotatably mounted within the cage pockets 730. The rolling
elements 728 may be generally conical having generally planar end
portions (e.g., frustoconical). In other embodiments, one or more
of the rolling elements 728 may have at least one generally curved
end portion, generally concave end portion, generally convex end
portion, generally pointed end portion, combinations thereof, or
other suitable end portion configurations. One or more of the
rolling elements 728 may be formed from any of the materials
discussed above for the rolling elements 128.
[0087] The stator 702 may include a plurality of circumferentially
adjacent superhard raceway elements 710 distributed about a
thrust-axis 714 and configured and located to at least partially
define a raceway for the rolling elements 728 to roll on or run
over. The superhard raceway elements 710 may each include a raceway
surface 718 configured to substantially lie on an imaginary conical
surface. The superhard raceway elements 710 may exhibit a geometric
shape that is generally formed by the intersection of two cylinders
(e.g., lune, lens, or crescent-shaped). In other embodiments, at
least one of the superhard raceway elements 710 may be generally
trapezoidal, generally elliptical, combinations thereof, or any
other suitable geometric shape. In an embodiment, the superhard
raceway elements 710 may be mounted or otherwise attached to at
least a lower surface 708D of the support ring 708. As shown, the
support ring 708 may include an upper surface 708C, the lower
surface 708D, an inner surface 708A, and an outer surface 708B. In
an embodiment, the inner surface 708A and the outer surface 708B
may extend between the upper surface 708C and the lower surface
708D. The inner surface 708A may be generally concentric and/or
congruent relative to the outer surface 708B. In other embodiments,
at least a portion of the inner surface 708A may be generally
incongruent and/or not centered relative to at least a portion of
the outer surface 708B. As illustrated, the lower surface 708D may
form an angle relative to the upper surface 708C and may form at
least a portion of a generally conical surface. For example, the
lower surface 708D may extend and taper between the inner surface
708A and the outer surface 708B.
[0088] The rotor 704 may include a support ring 720 and a plurality
of superhard raceway elements 722, with each of the superhard
raceway elements 722 having a raceway surface 724 configured to lie
on an imaginary conical surface. As shown, the superhard raceway
elements 722 may have a geometric shape that is generally formed by
the intersection of two cylinders. In other embodiments, the
superhard raceway elements 722 may have a geometric shape that is
generally oval, generally wedge-like, or any other suitable
geometric shape. Like the superhard raceway elements 710, the
superhard raceway elements 722 may be configured and positioned on
the support ring 720 to at least partially define a raceway for the
rolling elements 728 to run over or roll on during use. In an
embodiment, the superhard raceway elements 722 may be mounted or
otherwise attached to at least an upper surface 720C of the support
ring 720. As shown, the support ring 720 may include the upper
surface 720C, a lower surface 720D, an inner surface 720A, and an
outer surface 720B. In an embodiment, the inner surface 720A and
the outer surface 720B may extend between the upper surface 720C
and the lower surface 720D. The inner surface 720A may be generally
concentric and/or congruent relative to the outer surface 720B. In
other embodiments, at least a portion of the inner surface 720A may
be generally incongruent and/or not centered relative to at least a
portion of the outer surface 720B. As illustrated, the upper
surface 720C of the support ring 720 may form an angle relative to
the lower surface 720D and may form at least a portion of a
generally conical surface or a partial conical surface. For
example, the upper surface 720C may generally extend and taper
between the inner surface 720A and the outer surface 720B. In an
embodiment, the support ring 720 and/or the support ring 708 may
include a flange feature configured to help maintain the rolling
elements 728 between the stator 702 and the rotor 704. In other
embodiments, the flange feature(s) may be omitted. It is noted that
in other embodiments, the rotor or stator may be configured as any
of the previously described embodiments of thrust roller bearing
assemblies.
[0089] Any of the embodiments for roller bearing apparatuses
discussed above may be used in a subterranean drilling system. FIG.
9 is a schematic isometric cutaway view of a subterranean drilling
system 800 according to an embodiment. The subterranean drilling
system 800 may include a housing 860 enclosing a downhole drilling
motor 862 (i.e., a motor, turbine, or any other device capable of
rotating an output shaft) that may be operably connected to an
output shaft 856. A thrust roller bearing apparatus 864 may be
operably coupled to the downhole drilling motor 862. The thrust
roller bearing apparatus 864 may be configured as any of the
previously described thrust roller bearing apparatus embodiments. A
rotary drill bit 868 may be configured to engage a subterranean
formation and drill a borehole and may be connected to the output
shaft 856. The rotary drill bit 868 is shown comprising a bit body
890 that includes radially and longitudinally extending blades 892
with a plurality of polycrystalline diamond cutting elements 894
secured to the blades 892. However, other embodiments may utilize
different types of rotary drill bits, such as core bits and/or
roller-cone bits. As the borehole is drilled, pipe sections may be
connected to the subterranean drilling system 800 to form a drill
string capable of progressively drilling the borehole to a greater
depth within the earth.
[0090] The thrust roller bearing apparatus 864 may include a stator
872 that does not rotate and a rotor 874 that may be attached to
the output shaft 856 and rotates with the output shaft 856. The
thrust roller bearing apparatus 864 may further include a roller
assembly (not shown) interposed between the stator 872 and the
rotor 874. The roller assembly may include a cage having a
plurality of cage pockets (not shown) for retaining a plurality of
rolling elements (not shown). As discussed above, the thrust roller
bearing apparatus 864 may be configured as any of the embodiments
disclosed herein. For example, the stator 872 may include a
plurality of circumferentially-distributed superhard raceway
elements configured to at least partially define a raceway for the
rolling elements to roll over or run on. In addition, the rotor 874
may include a plurality of circumferentially-distributed superhard
raceway elements and configured to provide a raceway surface for
the rolling elements to roll or run on. The rolling elements may,
for example, include one or more superelastic materials such that
the rolling elements exhibit non-linear elastic deformation and
generally conform to the raceway during use.
[0091] While various aspects and embodiments have been disclosed
herein, other aspects and embodiments are contemplated. The various
aspects and embodiments disclosed herein are for purposes of
illustration and are not intended to be limiting. Additionally, the
words "including," "having," and variants thereof (e.g., "includes"
and "has") as used herein, including the claims, shall be open
ended and have the same meaning as the word "comprising" and
variants thereof (e.g., "comprise" and "comprises").
* * * * *