U.S. patent application number 13/692195 was filed with the patent office on 2013-06-27 for bearing unit for use in an axlebox of a railway vehicle and axlebox including the same.
This patent application is currently assigned to AKTIEBOLAGET SKF. The applicant listed for this patent is Xavier Blanchard, Thierry Le Moigne. Invention is credited to Xavier Blanchard, Thierry Le Moigne.
Application Number | 20130161969 13/692195 |
Document ID | / |
Family ID | 45495703 |
Filed Date | 2013-06-27 |
United States Patent
Application |
20130161969 |
Kind Code |
A1 |
Le Moigne; Thierry ; et
al. |
June 27, 2013 |
Bearing unit for use in an axlebox of a railway vehicle and axlebox
including the same
Abstract
The invention relates to a bearing unit for use in an axlebox of
a railway vehicle, including a bearing having an inner ring and a
metallic outer ring and rolling elements arranged therebetween. The
bearing is configured to support an axle of said railway vehicle.
Further, a sleeve surrounding the outer ring of the bearing is
provided. It is proposed that the sleeve is made of a non-metallic
material.
Inventors: |
Le Moigne; Thierry; (Reugny,
FR) ; Blanchard; Xavier; (Saint-Cyr-Sur-Loire,
FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Le Moigne; Thierry
Blanchard; Xavier |
Reugny
Saint-Cyr-Sur-Loire |
|
FR
FR |
|
|
Assignee: |
AKTIEBOLAGET SKF
Goteborg
SE
|
Family ID: |
45495703 |
Appl. No.: |
13/692195 |
Filed: |
December 3, 2012 |
Current U.S.
Class: |
295/36.1 ;
384/459 |
Current CPC
Class: |
F16C 33/586 20130101;
F16C 19/361 20130101; F16C 35/077 20130101; F16C 19/364 20130101;
F16C 27/066 20130101; F16C 2326/10 20130101; F16C 33/723 20130101;
F16C 19/543 20130101; F16C 19/386 20130101; B61F 15/12
20130101 |
Class at
Publication: |
295/36.1 ;
384/459 |
International
Class: |
B61F 15/12 20060101
B61F015/12 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 22, 2011 |
EP |
11290596 |
Claims
1. A bearing unit for use in an axlebox of a railway vehicle, the
unit comprising: a bearing having an inner ring and a metallic
outer ring and rolling elements arranged therebetween, the bearing
being configured to support an axle of the railway vehicle, a
sleeve surrounding the outer ring of the bearing; and the sleeve
being made of a non-metallic material.
2. The bearing unit according to claim 1, wherein the sleeve is
made of a polymer material.
3. The bearing unit according to claim 1, wherein the sleeve is
directly moulded onto said outer ring.
4. The bearing unit according to claim 1, wherein the outer ring
has a non-cylindrical outer surface.
5. The bearing unit according to claim 1, wherein an outer surface
of the outer ring has a concave portion in an axial
cross-section.
6. The bearing unit according to claim 1, wherein the bearing is a
double-row angular contact roller bearing, wherein a thickness of
said outer ring is basically constant over a width of two outer
raceways of the outer ring.
7. The bearing unit according to claim 1, wherein the sleeve has a
flat portion in its outer surface.
8. The bearing unit according to claim 1, wherein the outer ring is
split in two parts and being simultaneously overmoulded with the
same material used to fabricate the sleeve.
9. The bearing unit according to claim 8, wherein a distance
element is arranged between the two parts of the outer ring.
10. The bearing unit according to claim 1, wherein an outer surface
of the sleeve has a polygonal cross-section.
11. An axlebox for railway vehicles, including: a bearing having an
inner ring and a metallic outer ring and rolling elements arranged
therebetween, the bearing being configured to support an axle of
the railway vehicle, a sleeve surrounding the outer ring of the
bearing; and the sleeve being made of a non-metallic material; and
a metallic axlebox hosing accommodating the sleeve with the
bearing, wherein at least a part of the axlebox housing is
configured to remain connected with a suspension of the railway
vehicle when the axle is disconnected from the railway vehicle for
maintenance.
12. An axlebox according to claim 9, further comprising means for
mounting a front cover of the axle box, wherein the means for
mounting the axlebox are arranged provided in the sleeve.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This US Non-Provisional Utility application claims the
benefit of copending European Patent Application Serial No.
EP11290596 filed on Dec. 22, 2011, which is incorporated herein in
its entirety.
BACKGROUND OF THE INVENTION
[0002] Axlebox housings for railway vehicles as used e. g. in
bogies of high velocity trains comprise bearing units supporting
high axle loads of typically 20 tons and need to operate properly
in a wide range of temperatures and environmental conditions.
[0003] In order to ensure a safe functioning of the train including
axles and wheels, it is essential to have a regular maintenance
schedule, wherein the unsprung mass of the vehicle, in particular
the axle and the wheels, are disconnected from the sprung mass, e.
g. in order to detect microscopic cracks in the components
suspended below the suspension components of the vehicle. The
latter include the wheels, wheel bearings, brake rotors, callipers,
and/or caterpillar tracks, if any.
[0004] The axleboxes in modem high velocity trains do therefore not
only have to fulfill their primary function of mechanically
transferring loads from the suspension system to the axle bearing
and thus to the axle, but further need to provide interfaces for
easily disconnecting the sprung mass from the unsprung mass of the
vehicle or car.
[0005] It is therefore known to use a two-part or three-part design
of the axlebox housing including a sleeve surrounding the bearing
as a first part, which can be easily disconnected from the rest of
the housing, a part of which may remain connected with the
suspension system of the train when disconnecting the axle and/or
the brake system for maintenance reasons.
[0006] The sleeves of such multi-part housings are usually
basically cylindrical rings which are precisely machined and made
of steel. In order to ensure a good fitting and a reliable and
homogenous transfer of the load onto the outer ring of the bearing,
while enabling an easy disassembly, the interfaces between the
sleeve and the rest of the housing and between the sleeve and the
outer ring of the bearing have to be dimensioned with very high
precision. This precision can be practically achieved only for very
simple, in particular cylindrical shapes such that the range of
possible shapes of the circumferential surfaces of the sleeve and
of the outer ring of the bearing is very limited.
[0007] The invention seeks to overcome the above problems and
proposes a bearing unit that integrates the outer ring of the
bearing and the sleeve of the housing in one part and an axlebox
comprising such a bearing unit.
SUMMARY OF THE INVENTION
[0008] The invention starts from a bearing unit for use in an
axlebox of a railway vehicle. The vehicle may in particular be a
car of a high velocity train, a locomotive or a car of a freight
train. The bearing unit includes a bearing having an inner ring and
a metallic outer ring and rolling elements arranged therebetween.
Preferably, the bearing unit is a double row roller bearing with
cylindrical or tapered rollers manufactured according to EN12080 or
the like in order to meet the requirements imposed by the extreme
operating conditions when supporting an axle of the railway
vehicle. The outer ring of the roller bearing is surrounded by a
sleeve preferably covering the entire radially outer surface of the
outer ring.
[0009] It is proposed that the sleeve is made of a non-metallic
material. The inventors have found that the conventional exclusive
use of high-performance steel for sleeves in multi-part axlebox
housings was the result of a technical prejudice, i. e. that the
extreme operating conditions require the use of this material. The
inventors have found that the requirements may be met with sleeves
which may be manufactured in a less expensive way, e. g. of
ceramics or polymers.
[0010] In particular when the sleeve is made of a polymer material,
the flexibility of this material may ensure good fitting properties
while keeping the manufacturing costs low. Further, polymer sleeves
may be manufactured in a simple way in a wide variety of possible
shapes. A perfect connection between the sleeve and the outer ring
may be obtained when the sleeve is directly mounted onto the outer
ring. The outer ring may in the latter case have a non-cylindrical
surface, which may e. g. comprise a concave portion in an axial
cross-section ensuring a good and stable connection between the
outer ring and the sleeve in an axial direction. This may be
realized e. g. by a waisted shape of the outer surface which may
have a rotational symmetry around the centre axis of the outer ring
for the sake of good machining properties.
[0011] As a consequence of the increased freedom of design for the
outer ring, a thickness thereof can be basically constant over the
width of the two outer raceways formed in the radially inner
surface of the outer ring even if the bearing is an angular contact
bearing, e. g. a double-row angular contact bearing.
[0012] It is preferable that the sleeve has a flat portion on its
outer surface in order to simplify a rotational fixation in the
rest of the housing.
[0013] The sleeve may e. g. have a polygonal cross-section, be
quadratic, hexagonal or irregular.
[0014] A further aspect of the invention relates to an axlebox for
railway vehicles including a bearing unit with a sleeve and a
bearing as described above and a metallic axlebox housing
accommodating the sleeve with the roller bearing, wherein at least
a part of the axlebox is configured to remain connected with a
suspension of the railway car when the axle is disconnected from
the railway car for maintenance.
[0015] In a preferable embodiment of the invention, the sleeve may
comprise means for mounting a front cover of the axlebox, e. g.
holes for screws or the like. In modem applications, the front
cover of axleboxes is often provided with electronic sensors
detecting the velocity of rotation of the axle and/or its
temperature in order to ensure that no axle of the train is
blocking.
[0016] Various types of front covers with and without sensors and
with different types of sensors may be used in different types of
trains. Providing the mounting holes or mounting means in or on the
sleeve which is made of a non-metallic material, in particular made
of plastics, enables a simple adaptation of the bearing unit to the
front cover/sensor system employed. The remaining parts of the
bearing unit and the axlebox housing may remain unchanged even if
other types of front covers are employed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In order that the present invention may be well understood
there will now be described a preferred embodiment thereof, given
by way of example, reference being made to the accompanying
drawings, in which:
[0018] FIG. 1 Is an exploded view of an axlebox including a bearing
unit according to the present invention;
[0019] FIG. 2 Is a cross-sectional view of an axlebox according to
FIG. 1;
[0020] FIG. 3 Is an axle front view of the axlebox according to
FIGS. 1 and 2;
[0021] FIG. 4 Is a cross-sectional view of a second embodiment of
the axlebox according to the present invention;
[0022] FIG. 5 Is a perspective view of the second embodiment of the
axlebox according to the present invention;
[0023] FIG. 6 Is a third embodiment the axlebox according to the
present invention;
[0024] FIG. 7 Illustrates a fourth embodiment of the present
invention; and
[0025] FIG. 8 Is a sixth embodiment of the axlebox according to the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0026] The below description of preferred embodiments of the
invention and the appended figures as well as the claims comprise
multiple features in a specific combination. A skilled person will
easily be able to consider further combinations or sub-combinations
of these features in order to adapt the invention as defined in the
claims to specific needs. The description of the below embodiments
of the invention should by no means be construed as limiting the
scope of the invention as defined in the claims, but rather to
enable the skilled person to carry out the invention for a certain
group of applications.
[0027] FIG. 1 is an explosion view of an axlebox for railway
vehicles including a double-row angular contact tapered roller
bearing 10 with an inner ring 12 (FIG. 2) and an outer ring 14
(FIG. 2) and a sleeve 16. Rolling elements 48 formed as cylindrical
or tapered rollers are provided between the inner ring 12 and the
outer ring 14. The axlebox housing comprises an upper part 18 and a
lower part 20 both being made of cast iron, constituting together a
swing-arm type axlebox with a journal 22 for connecting the axlebox
with a pivot plank of the bogie, so as to enable a pivotal movement
around the journal 22.
[0028] The upper part 18 and the lower part 20 each comprise a
semi-circular shell complementing each other to form a circular
bushing for enclosing the sleeve 16 of the bearing unit in the
assembled state as shown in FIG. 2. In this state, the upper part
18 and the lower part 20 of the housing exerts a certain pressure
onto the sleeve 16 in order to ensure a stable fixation. The sleeve
16 is provided with a flat portion 24 mating with a flat portion
(not shown) on the backside of a plate-shaped support of the upper
part 18 of the housing, which support 26 is configured to carry the
load transmitted via a suspension spring (not shown) arranged
thereon.
[0029] The end portion of an axle 28 is inserted into the inner
ring 12 of the bearing 10 and is provided with threaded holes on
its axial end face for receiving bolts for fixing an endplate 30 of
the assembly. The endplate 30 and a distance element 32 (FIG. 2)
fix the axial position of the inner ring 12 of the bearing 10 on
the axle 28.
[0030] The upper part 18 and the lower part 20 of the housing are
provided with mating through-holes for receiving bolts 34 for
closing the housing and for clamping the bearing unit.
[0031] A front cover 36 of the bearing unit is provided with sensor
means for measuring the rotation and/or the temperature of the
bearing unit in a suitable way. The outer ring 14 of the bearing 10
may be provided with an interface 38 for transferring data and/or
measurement currents to the sensors (not shown) provided in the
front cover 36.
[0032] The front cover 36 is connected to the sleeve 16 by means of
bolts engaging with corresponding threaded holes in the sleeve 16
(not shown).
[0033] As an important feature of the invention, the sleeve 16 is
made of a non-metallic material, in the illustrated case of a
polymer material, which may e. g. a polymer of the type PA6.6 with
some fibre enforcement, e. g. with 20% to 30% of glass fibre. In
alternative embodiments, the polymer material might be reinforced
with carbon fibres or may be made of engineering ceramics.
[0034] Further, although the sleeve 16 may be fitted over the outer
ring 14, it is preferable that the sleeve is directly and
permanently moulded onto the outer ring, e. g. by injection
moulding or the like in order to ensure a reliable fixation.
[0035] As shown in FIG. 2, the sleeve 16 of this embodiment is
provided with a shoulder 42 protruding radially inward and abutting
with the axial end face of the outer ring 14 and an end ring 44
with a backside cover is fitted into an end portion of the sleeve
16 axially protruding over the outer surface of the outer ring
14.
[0036] The inner ring 12 is configured as a split ring with a
distance ring arranged between its two parts. Alternatively, the
inner ring 12 may be a single part supporting the two rows of
rolling elements 48.
[0037] FIG. 3 shows an axial view of the radially assembled axial
box. The flat portion 24 of the sleeve 16, which is provided for
avoiding a rotation of the sleeve within the semicircular shells of
upper part 18 and the lower part 20, is provided on an outer rim 46
of the front cover 36 in the same way.
[0038] Due to the fact that the sleeve 16 is formed of plastics or
a polymer material instead of metal, the weight of the overall
assembly is considerably reduced and the assembly and disassembly
is facilitated. Further, all types of corrosion (fretting
corrosion, galvanic corrosion, and classic corrosion) may be
efficiently avoided and an electric isolation between the housing
and the axle 28 is ensured. The latter feature may reduce or
eliminate electric damages to bearing elements. No or less
machining is needed more manufacturing the sleeve 16, and the
number of surfaces to be machined may be reduced. The flexibility
of the sleeve 16 reduces the requirements on the precision of the
machining of the semicircular shells of the upper part 18 and the
lower part 20.
[0039] FIGS. 4 to 8 show further embodiments of the invention. The
following description of these embodiments employs the same
reference numbers for features with similar or equivalent functions
and is essentially limited to the description of differences to the
embodiments of FIGS. 1 to 3, whereas the reader is referred to the
above description of the first embodiment for features which remain
unchanged.
[0040] FIGS. 4 and 5 show a second embodiment of the invention
respectively in a cross-sectional and a cross-sectional perspective
view. In this second embodiment, the sleeve 16 is overmoulded over
the outer ring 14 of the bearing 10 in an injection moulding
process. The sleeve 16 is made of a polymer material which may be
reinforced by glass fibres. The outer ring 14 has a radially outer
surface, the shape of which corresponds to the shape of a
double-cone, i. e. the outer diameter is continuously reduced from
the axial ends of the outer ring 14 towards its midpoint in the
axial direction.
[0041] The decrease of the outer diameter is basically identical to
the decreasing outer diameter of the tapered raceways of the outer
ring 14 of the angular contact cylindrical roller bearing 10. As a
consequence, the thickness of the material constituting the outer
ring 14 is essentially constant over the width of the raceway.
[0042] The sleeve 16 is perfectly fitted into the concave portion
of the outer surface of the outer ring 14, i. e. the portion which
is concave in the axial direction or viewed in an axial
cross-section and which is arranged in the axial centre portion of
the outer ring 14 due to the manufacturing method employed. The
outer surface of the sleeve 16 is basically cylindrical and
contacts the semicircular shells of the upper part 18 and the lower
part 20 of the housing without any gap. The sleeve 16 extends over
both axial ends of the outer ring 14 of the bearing 10 and also
covers the axial end faces thereof such that an axial relative
movement of the outer ring 14 within the sleeve 16 is safely
avoided. The part of the sleeve 16 protruding over the axial end of
the outer ring 14 in the direction of the end of the axle 28 is
provided with mounting holes (not shown) for mounting the front
cover 36, whereas the opposite end of the sleeve 16 oriented
towards the wheel of the railway vehicle axially overlaps with the
radially protruding ring of a distance element 32 with a small gap
therebetween preventing a labyrinth seal of the arrangement from
impacts of coarse-grained external impurities.
[0043] FIG. 6 is a third embodiment of the invention with a split
outer ring comprising a left outer ring 14a and a right outer ring
14b, which are simultaneously overmoulded with the sleeve 16 made
of polymer material. Each of the outer rings 14a, 14b comprises one
raceway for a set of cylindrical or conical rolling elements 48.
The alignment of the rings 14a, 14b is adjusted and fixed during
the injection moulding procedure connecting the rings 14a, 14b and
the sleeve 16 to form a single end non-dismantleable element.
[0044] FIG. 7 is a fourth embodiment of the invention with a split
outer ring, comprising a left outer ring 14a and a right outer ring
14b, similar to the third embodiment of FIG. 5, wherein a distance
element 50 such as a distance ring is integrally cast with the
sleeve 16 in order to ensure a predetermined distance between the
rings 14a and 14b in axial direction. The distance element 50 may
be provided with radial holes allowing for a through flow of the
casting material and/or with other types of cast channels.
[0045] FIG. 8 is a fifth embodiment of the invention wherein the
sleeve 16 axially abuts to a metal shoulder 52 of the upper and/or
lover housing part 18, 20 in order to more reliably and directly
transfer axial loads from the outer ring 14 to the housing 18,
20.
* * * * *