U.S. patent application number 11/867942 was filed with the patent office on 2008-04-10 for railroad bearing with corrosion inhibitor.
This patent application is currently assigned to THE TIMKEN COMPANY. Invention is credited to Stephen E. Brister, James R. Callan, Brian M. Hupp, David G. Toth.
Application Number | 20080085069 11/867942 |
Document ID | / |
Family ID | 39274999 |
Filed Date | 2008-04-10 |
United States Patent
Application |
20080085069 |
Kind Code |
A1 |
Toth; David G. ; et
al. |
April 10, 2008 |
RAILROAD BEARING WITH CORROSION INHIBITOR
Abstract
A backing ring that serves to position an antifriction bearing
on the journal of an axle for a railcar or locomotive carries a
ring containing a corrosion inhibitor. During installation of the
bearing on the journal, the backing ring is advanced over the
journal followed by the bearing. When the axially directed force
that advances the bearing over the journal is transmitted through
the bearing to the backing and is resisted at the fillet, the
corrosion inhibitor exudes from the backing ring and forms a
coating on the fillet to inhibit fretting and other corrosion
between the backing ring and the journal.
Inventors: |
Toth; David G.; (North
Canton, OH) ; Callan; James R.; (New London, NH)
; Hupp; Brian M.; (Canton, OH) ; Brister; Stephen
E.; (North Canton, OH) |
Correspondence
Address: |
POLSTER, LIEDER, WOODRUFF & LUCCHESI
12412 POWERSCOURT DRIVE SUITE 200
ST. LOUIS
MO
63131-3615
US
|
Assignee: |
THE TIMKEN COMPANY
Canton
OH
|
Family ID: |
39274999 |
Appl. No.: |
11/867942 |
Filed: |
October 5, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60849892 |
Oct 6, 2006 |
|
|
|
60915156 |
May 1, 2007 |
|
|
|
Current U.S.
Class: |
384/459 |
Current CPC
Class: |
F16C 33/768 20130101;
F16C 33/7813 20130101; B61F 15/26 20130101; F16C 2326/10
20130101 |
Class at
Publication: |
384/459 |
International
Class: |
B61F 15/12 20060101
B61F015/12; B61F 15/26 20060101 B61F015/26 |
Claims
1. An assembly for installation over an axle journal having a
fillet at one end, said assembly comprising: an antifriction
bearing defining an axis of rotation; a backing ring aligned
axially with the antifriction bearing; a corrosion inhibitor
carried by the backing ring for release onto the fillet of the axle
journal upon installation of the assembly over the axle
journal.
2. An assembly according to claim 1 wherein the backing ring has a
contoured inner surface configured to seat against the fillet, with
the inner surface having a large end and a small end.
3. An assembly according to claim 2 and further comprising a wear
ring located between the bearing and the backing ring and aligned
with both; wherein the backing ring at the small end of the
contoured inner surface has a counterbore that ends at a shoulder
in the backing ring; wherein the wear ring fits into the
counterbore; and wherein the corrosion inhibitor also fits into the
counterbore between the end of the wear ring and the shoulder.
4. An assembly according to claim 3 wherein the corrosion inhibitor
takes the form of a ring.
5. An assembly according to claim 2 wherein the corrosion inhibitor
is at the large end of the contoured inner surface on the backing
ring.
6. An assembly according to claim 5 wherein the backing ring has a
lip that projects axially beyond the large end of the contoured
inner surface and the corrosion inhibitor is within the lip.
7. An assembly according to claim 6 wherein the corrosion inhibitor
takes the form of a ring.
8. In combination with an axle journal having a cylindrical portion
and a fillet at the end of the cylindrical portion, the improvement
comprising: a backing ring that is advanced over the journal to
ultimately seat against the fillet and provide a backing for an
antifriction bearing, and a corrosion inhibitor carried by the
backing ring and configured to exude over the fillet under a force
applied to the backing ring when advancement of the backing ring is
resisted at the fillet.
9. The combination according to claim 8 wherein the backing ring
has a contoured inner surface along which the backing ring will
ultimately seat against the fillet, with the surface having a large
end and a small end; wherein the backing ring also has a
counterbore at the small end of the contoured surface; and wherein
the corrosion inhibitor is in the counterbore.
10. The combination according to claim 9 wherein the corrosion
inhibitor is the form of a ring.
11. The combination according to claim 8 wherein the backing ring
has a contoured inner surface along which the backing ring will
ultimately seat against the fillet, with the contoured surface
having a small end and a large end; and wherein the corrosion
inhibitor is at the large end of the contoured surface.
12. The combination according to claim 11 wherein the backing ring
has a lip that projects axially beyond the large end of the
contoured surface; and wherein the corrosion inhibitor is within
the lip.
13. The combination according to claim 12 wherein the corrosion
inhibitor is in the form of a ring.
14. The combination according to claim 8 and further comprising an
antifriction bearing around the journal, with the backing ring
being between the fillet and the antifriction bearing.
15. A process for installing a backing ring over an axle journal
having a cylindrical portion and a fillet at one end of the
cylindrical portion, said process comprising: providing the backing
ring with a corrosion inhibitor; advancing the backing ring over
the cylindrical portion of the journal substantially without
releasing the corrosion inhibitor; and releasing the corrosion
inhibitor onto the fillet when the backing ring encounters the
fillet.
16. The process according to claim 15 wherein the corrosion
inhibitor is released by applying an axially directed force to the
backing ring.
17. A process according to claim 15 wherein the backing ring has a
contoured inner surface with a large end and a small end, and the
backing ring also has a counterbore at the small end of the
contoured surface and a shoulder at the end of the counterbore, and
further comprising: inserting the corrosion inhibitor into the
counterbore; inserting a wear ring into the counterbore such that
the corrosion inhibitor is captured between the wear ring and the
shoulder; and when the backing ring encounters the fillet, forcing
the wear ring into the counterbore to cause the corrosion inhibitor
to exude from the counterbore onto the fillet.
18. A process according to claim 15 wherein the backing ring has a
contoured inner surface with a large end and a small end; and
wherein the corrosion inhibitor is at the large end of contoured
surface where it will exude over the fillet as the backing ring is
forced toward the fillet.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application derives and claims priority from U.S.
provisional application 60/849,892, filed Oct. 6, 2006, and from
U.S. provisional application 60/915,156, filed May 1, 2007, both of
which are incorporated herein by reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
[0002] Not applicable.
BACKGROUND OF THE INVENTION
[0003] This invention relates to bearing assemblies for the axles
or railcars and locomotives and, more particularly, to a bearing
assembly having a backing ring that carries its own supply of a
corrosion inhibitor, to the backing ring itself, and to a process
for installing the backing ring over an axle journal.
[0004] The typical railcar or locomotive has axles to which its
wheels are fitted, and those axles at their ends have journals
through which the weight of the car or locomotive is transferred to
the wheels. Each bearing is clamped between a backing ring that
seats against a fillet at the inboard end of the journal and an end
cap that extends across the outboard end of the journal. Sometimes
wear rings are interposed between the bearing and backing ring and
between the bearing and end cap. Owing to the offset between each
bearing and its nearby wheel, the journal around which the bearing
fits flexes slightly as the axle revolves. This flexure produces
movement between the backing ring and the journal fillet against
which the backing ring seats. The movement may lead to fretting
corrosion and damage to the journal. To retard fretting corrosion,
the installation of a bearing over an axle journal is usually
accompanied by the application of a liquid corrosion inhibitor to
the fillet of the journal. But this is a manual operation that
consumes time and those charged with it sometimes forget to apply
the inhibitor.
DESCRIPTION OF THE INVENTION
[0005] FIG. 1 is longitudinal sectional view of a bearing assembly
fully installed over an axle journal in accordance with the present
invention, so that the axle journal is coated with a corrosion
inhibitor that is initially carried by the backing ring of the
assembly;
[0006] FIG. 2 is a half-sectional view of the bearing assembly
during its installation over the axel journal;
[0007] FIG. 3 is an enlarged sectional view of the segment within
the circle of FIG. 2 and showing the ring of inhibitor captured in
the backing ring;
[0008] FIG. 4. is a half-sectional view of a bearing assembly with
an alternative backing ring during its installation over an axle
journal;
[0009] FIG. 5 is an enlarged sectional view of the segment within
the circle of FIG. 4 and showing an inhibitor ring within the large
end of the backing ring; and
[0010] FIG. 6 is a perspective view of the modified backing ring
with the inhibitor ring exposed within it.
DETAILED DESCRIPTION
[0011] Before any embodiments of the invention are explained in
detail, it is to be understood that the invention is not limited in
its application to the details of construction and the arrangement
of components set forth in the following description or illustrated
in the drawings.
[0012] Referring now to the drawings (FIG. 1) an axle A for a
railcar or locomotive is fitted with a bearing B and a wheel W that
is set inwardly from the bearing B. The wheel W rolls along the
rail of a railroad track, and as it does the axle A rotates about
its longitudinal axis X. The weight of the railcar or locomotive
transfers through the bearing B to the axle A and thence through
the axle A to the wheel W where it is resisted by the underlying
rail. Actually, the axle A is one of several axles A under a
railcar or locomotive, with each axle A having two wheels W and two
bearings B beyond the wheels W. Owing to the axial offset between
the bearings B and the wheels W, the axle A undergoes slight
flexures in the regions of offset.
[0013] The axle A at each of its ends has a journal 2 which leads
to a somewhat larger dust guard segment 4 at a fillet 6 on the
journal 2. Inwardly from the dust guard segment 4 the axle A has an
even larger wheel seat to which the wheel W is fitted. The journal
2 extends out to an end face 8 out of which threaded holes open.
The journal 2 for the most part and the dust guard segment 4 are
cylindrical and concentric, with their common center being the axis
X. The fillet 6 has a contoured surface that is concave.
[0014] The bearing B fits around the journal 2 (FIG. 1) where it is
captured between a backing ring 10 that bears against the fillet 6
and an end cap 12 that extends over the end face 8, yet is spaced
slightly outwardly from it. The bearing B is separated from the
backing ring 10 and from the end cap 12 by wear rings 14, and all
are clamped tightly together with cap screws 16 which thread into
the holes in the end of the journal 2 and bear against the end cap
12. The wear rings 14 adjacent to the bearing B fit snugly over the
journal 2, but remote from the bearing B a clearance exists between
each wear ring 14 and the journal B owing to an undercut in the
wear ring 14. The bearing B together with the backing ring 10, the
end cap 12, and the wear rings 12 form a bearing assembly.
[0015] The bearing B includes (FIG. 1) an outer race in the form of
a cup 20, an inner race in the form of two cones 22 located within
the cup 16, and rolling elements in the form of tapered rollers 24
located between the cup 20 and cones 22. In addition, the bearing B
includes a spacer 26 located between the two cones 22 to maintain a
prescribed spacing between the cones 22. The ends of the bearing B
are closed by seals 28 located between the ends of the cup 20 and
the wear rings 14. The cones 22 fit over the journal 2 of the axle
A with interference fits, with the spacer 26 between them. The cup
20 fits into an adapter which in turn fits into the truck of a
railcar or locomotive. The tapered rollers 24 lie along tapered
raceways 30 on the cup 20 and cones 22 where they are organized in
two rows--one around the inboard cone 22 and the other around the
outboard cone 22. The raceways 30 of the two cones 22 taper in
opposite directions and so do the two raceways of the cup 20. This
orients the rollers 24 such that the rollers 24 of the inboard row
take thrust or axial loads in one direction, and the rollers 24 of
the outboard row take thrust in the opposite direction. The rollers
24 of both rows transfer radial loads. The cones 22 at the large
ends of their raceways 30 have thrust ribs 32 which confine the
rollers 24 to the annular spaces between the raceways 30 of the cup
20 and cones 22. The thrust rib 30 of each cone 22 leads out to
back face 34, which is squared off with respect to the axis X. The
bearing B transfers thrust loads to the axle A primarily at the
back faces 32 of its cones 22.
[0016] Actually, the thrust loads transferred through the inboard
cone 22 and rollers 24 pass to the journal 2--and axle A--through
the inboard wear ring 14 and the backing ring 10 which lie between
the back face 34 of the inboard cone 22 and the fillet 6 on the
journal 2. The thrust loads transferred through the outboard cone
22 and rollers 24 pass to the journal 2 through the outboard wear
ring 14, the end cap 12 and the cap screws 16. The end cap 12 fits
over the end of the journal 2 and against the outboard wear ring 14
which in turn is against the back face 34 of the outboard cone 22.
The cap screws 16 clamp the two cones 22 and the spacer 26 and the
wear rings 14 tightly between the backing ring 10 and the end cap
12 and urge the backing ring 10 firmly against the fillet 6. Radial
loads transfer through the bearing B and through the journal 2 and
dust guard segment 4 to the nearby wheel W, and owing to the
offset, create a moment.
[0017] Turning now to the backing ring 10, it has (FIG. 1) a
contoured inner surface 36 that seats snugly against the fillet 6.
Beyond the larger end of the contoured surface 36, the backing ring
10 has a lip 38 that projects over the dust guard segment 4 when
the backing ring 10 is fully seated against the fillet 6.
Preferably, a interference fit exists between the lip 38 and the
dust guard segment 4 to reduce motion between the backing ring 10
and the fillet 6. At its opposite end the backing ring 10 has a
counterbore 40 that opens toward the bearing B and receives the end
of the inboard wear ring 14 with an interference fit. The
counterbore 40 leads up to and terminates at a shoulder 42. When
the bearing B is fully installed over the journal 2, the end of the
inboard wear ring 14 for all intents and purpose abuts the shoulder
42. Indeed, the cap screws 16 clamp the inboard wear ring 14
tightly against the shoulder 42.
[0018] As the axle A revolves, it will experience some flexure,
inasmuch as the bearing B through which weight is transferred to
the axle A is offset from the nearby wheel W that transfers the
weight to the rail over which the wheel W rolls. The flexure to a
large measure is concentrated in the region of the journal 2 around
which the inboard wear ring 14 and backing ring 10 are located. The
inboard wear ring 14 sees some motion on the cylindrical surface of
the journal 2, whereas the backing ring 10 experiences motion on
the fillet 6, its contoured inner surface 36 slipping minutely back
and forth on the concave surface of the fillet 6. To minimize
fretting corrosion along the fillet 6 and journal 2, a coating 44
designed to lubricate and inhibit corrosion covers the fillet 6 and
the nearby region of the journal 2.
[0019] The coating 44 derives from an inhibitor ring 50 (FIGS. 2
and 3) and is released as the bearing B, the backing ring 10, and
the wear rings 14 are installed over the journal 2--indeed, as they
are advanced to their final positions over the journal 2. In this
regard, the seals 28 at the ends of the cup 20 retain the wear
rings 14 in alignment with the cones 22. The remote end of the
inboard wear ring 14, that is the end that is offset from the back
face 34 of the inboard cone 22, fits into the counterbore 40 of the
backing ring 10 where it is retained by the interference fit, but
not against the shoulder 42 at the end of the counterbore 40.
Hence, a space exists between the end of the inboard wear ring 14
and the shoulder 42. The inhibitor ring 50 occupies that space.
Preferably, the inside diameter of the inhibitor ring 50 exceeds
the diameter of the cylindrical region of the journal 2.
[0020] Thus, the bearing B, wear rings 14, and backing ring 10 form
an assembly and are installed over the journal 2 of the axle A as a
package. More specifically, the backing ring 10 is aligned with the
end of the journal 2, over which it is advanced followed by the
inboard wear ring 14 that is captured in the backing ring 10. Due
to the interference fits with the journal 2, a force is applied to
the outboard wear ring 14 to press the inboard wear ring 14, the
two cones 22 along with the spacer 26, and the outboard wear ring
14 over the cylindrical region of the journal 2. Continued
advancement brings either the lip 38 into contact with the dust
guard segment 4 or the backing ring 10 into contact with the fillet
6 of the journal 2, depending on, whether or not a lip 38 is small
enough to interfere with the dust guard segment 4. In any event,
the backing ring 10 no longer advances, but not the wear rings 14
and the cones 22 of the bearing B behind it. They continue to
advance, driving the inboard wear ring 14 farther into the
counterbore 44 of the backing ring 10. The inboard wear ring 14
advances until its end bottoms out against the shoulder 42 at the
end of the counterbore 40. Ultimately, the wear rings 14 and
bearing B assume their final positions over the journal 2. During
the increment of advance that forces the inboard wear ring 14
farther into the counterbore 40 of the backing ring 10, the
inhibitor ring 50 collapses and the corrosion inhibitor of which it
is formed flows or exudes onto the surface of the fillet 6 and the
nearby cylindrical surface of the journal 2, that is to say, the
surface over which the inboard wear ring 14 fits. The inhibitor
covers those surfaces and works under both the backing ring 10 and
the inboard wear ring 14 to provide the coating 44 that lubricates
and inhibits fretting corrosion.
[0021] The inhibitor ring 50 may be formed from a solid or
semi-solid material which will flow and deform under pressure, such
as a wax or dense grease having the desired corrosion inhibiting,
lubricating, and rust preventative properties. Alternatively, the
ring 50 may be formed as a tubular O-ring containing a liquid or
viscous corrosion inhibitor. The O-ring has walls preferably formed
from a polymer that is no more than a few mills thick. Moreover,
the polymer is compatible with the corrosion inhibitor in the sense
that the corrosion inhibitor will not react with or otherwise cause
deterioration of the polymer. Irrespective of its composition, the
inhibitor ring 50 is considerably softer than the steels from which
the axle A, the wear rings 14, and the backing 10 are formed, so
that when compressed between any two of those components, its
corrosion inhibitor will exude onto the fillet 6.
[0022] An alternative backing ring 60 (FIGS. 4-6) likewise has a
contoured inner surface 62 along which the backing ring 60 seats
against the fillet 6 at the inner end of the journal 2. Beyond the
large end of the contoured surface 62 the backing ring 60 has a lip
64 that fits over the dust guard segment 4, preferably with an
interference fit. At its opposite end the backing ring 60 has a
counterbore 66 that receives the end of the inboard wear ring 14
with an interference fit. The fillet 6 and the contoured inner
surface 62 along which the backing ring 60 seats against the fillet
6 are covered with a coating 68 that inhibits corrosion, including
fretting corrosion.
[0023] Initially, that is to say prior to the installation of the
bearing B, the wear rings 14, and the backing ring 60, over the
journal 2, the backing ring 60 has an inhibitor ring 70 located
within its axially directed lip 64. The ring 70 conforms to the
inside surface of the lip 64 and may also conform to the adjacent
region of the contoured inner surface 62. The diameter of dust
guard segment 4 should exceed the inside diameter of the inhibitor
ring 70. Anyone of the materials that are suitable for the
inhibitor ring 50 may likewise be used for the inhibitor ring
70.
[0024] The backing ring 60 and then the bearing B with the wear
rings 14 fitted into its seals 28 are installed over the journal 2
in that order, the inboard wear ring 14 having been pressed into
the counterbore 66 of the backing ring 60 (FIG. 4). Then the
bearing B, along with its wear rings 14 and the backing ring 60 are
advanced over the journal 2 with the backing ring 60 leading. As
the backing ring 60 moves over the fillet 6, the inhibitor ring 70
will align with and eventually come in contact with the larger end
of the fillet 6, that is, the region where the fillet 6 merges into
the dust guard segment 4 (FIG. 5). Continued advancement causes the
inhibitor ring 70 to compress and exude inhibitor over the fillet 6
and along the contoured surface 62 of the backing ring 60, forming
the coating 68 on those surfaces. Ultimately, the end cap 12 is
installed on the journal 2 and secured with the cap screws 16.
[0025] The end cap 12 retains the bearing B, the wear rings 14, and
the backing ring 10 on the journal with the backing ring 60 seated
firmly against the fillet 6. The coating 68 inhibits corrosion,
including fretting corrosion, between the backing ring 10 and the
fillet 6 and between the inboard wear ring 14 and the cylindrical
surface of the journal 2.
[0026] The backing ring 60 with a slight modification may be
installed over a shortened and stiffened journal fitted with a
compact bearing of the type disclosed in U.S. Pat. No. 5,462,367.
That modification would simply allow the end of the backing ring to
abut the back face of the inboard cone. Moreover, the backing ring
10 or 60 need not be united with the inboard wear ring 14 prior to
installation over the journal 2, but may be installed over the
journal 2 ahead of the bearing B and wear rings 14.
* * * * *