U.S. patent application number 14/268466 was filed with the patent office on 2014-08-28 for hydrodynamic axial bearing.
This patent application is currently assigned to ABB Turbo Systems AG. The applicant listed for this patent is ABB Turbo Systems AG. Invention is credited to Bruno Ammann, Marco Di Pietro, Peter NEUENSCHWANDER, Markus Stadeli.
Application Number | 20140241887 14/268466 |
Document ID | / |
Family ID | 47222025 |
Filed Date | 2014-08-28 |
United States Patent
Application |
20140241887 |
Kind Code |
A1 |
NEUENSCHWANDER; Peter ; et
al. |
August 28, 2014 |
HYDRODYNAMIC AXIAL BEARING
Abstract
A hydrodynamic axial bearing for mounting a shaft which is
mounted rotatably in a bearing housing, including an axial stop of
the bearing housing and a bearing comb which rotates with the
shaft. A lubricating gap, which is loaded with lubricating oil and
is delimited by a profiled circular ring face and a sliding face,
being formed between the axial stop and the bearing comb. The
profiled circular ring face and the sliding face are configured in
such a way that the lubricating gap is constricted radially to the
outside with regard to the axial direction. As a result,
temperature deformations which occur during operation and
deformations on account of centrifugal, shearing and other forces
in the bearing comb can be compensated for.
Inventors: |
NEUENSCHWANDER; Peter;
(Zurich, CH) ; Ammann; Bruno; (Aarau, CH) ;
Di Pietro; Marco; (Oftringen, CH) ; Stadeli;
Markus; (Zurich, CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ABB Turbo Systems AG |
Baden |
|
CH |
|
|
Assignee: |
ABB Turbo Systems AG
Baden
CH
|
Family ID: |
47222025 |
Appl. No.: |
14/268466 |
Filed: |
May 2, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2012/071729 |
Nov 2, 2012 |
|
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14268466 |
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Current U.S.
Class: |
416/174 ;
384/123 |
Current CPC
Class: |
F01D 25/168 20130101;
F16C 17/04 20130101; F16C 17/18 20130101; F01D 25/18 20130101; F05D
2240/53 20130101; F16C 33/1075 20130101; F16C 2360/24 20130101;
F04D 29/057 20130101 |
Class at
Publication: |
416/174 ;
384/123 |
International
Class: |
F01D 25/16 20060101
F01D025/16; F01D 25/18 20060101 F01D025/18; F04D 29/057 20060101
F04D029/057 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 3, 2011 |
DE |
102011085681.1 |
Claims
1. A hydrodynamic axial bearing for mounting a shaft mounted
rotatably in a bearing housing, the hydrodynamic axial bearing
comprising: an axial stop; a bearing comb for rotation with a shaft
when installed; and at least one lubricating gap formed between the
axial stop and the bearing comb for receiving lubricating oil, and
delimited by a profiled circular ring face and a planar sliding
face which lies opposite the circular ring face, the profiled
circular ring face being configured so as to rotate around or with
the shaft, the profile of the circular ring face having a plurality
of segments, each segment including one radially running
lubricating oil groove, a wedge face connected to the lubricating
oil groove in a circumferential direction, and a rest face which
adjoins the wedge face in the circumferential direction, wherein,
for the at least one lubricating gap, the rest face and the planar
sliding face are configured such that the lubricating gap,
delimited by the rest face and the planar sliding face, is
constricted radially to the outside with regard to an axis of
rotation.
2. The hydrodynamic axial bearing as claimed in claim 1, wherein
the axial stop comprises: the planar sliding face, the planar
sliding face delimiting the lubricating gap constricted radially to
the outside, the planar sliding face being configured to be
inclined toward the bearing comb at least in a radially outer part
in a manner which deviates from a plane which lies perpendicularly
with respect to the axis of rotation.
3. The hydrodynamic axial bearing as claimed in claim 1, wherein
the bearing comb comprises: the planar sliding face, the planar
sliding face delimiting the lubricating gap constricted radially to
the outside, the planar sliding face being configured to be
inclined toward the axial stop in a manner which deviates from a
plane which lies perpendicularly with respect to the axis of
rotation.
4. The hydrodynamic axial bearing as claimed in claim 1,
comprising: a floating disk arranged axially between the axial stop
and the bearing comb, the lubricating gap being formed between the
floating disk and the bearing comb.
5. The hydrodynamic axial bearing as claimed in claim 2,
comprising: a floating disk arranged axially between the axial stop
and the bearing comb, the lubricating gap being formed between the
floating disk and the bearing comb.
6. The hydrodynamic axial bearing as claimed in claim 3,
comprising: a floating disk arranged axially between the axial stop
and the bearing comb, the lubricating gap being formed between the
floating disk and the bearing comb.
7. The hydrodynamic axial bearing as claimed in claim 6, wherein
the floating disk comprises: the profiled circular ring face, and
the planar sliding face of the bearing comb and the circular ring
face of the floating disk delimit the lubricating gap which is
constricted radially to the outside, the planar sliding face of the
bearing comb being configured to be inclined toward the axial stop,
at least in a radially outer part, in a manner which deviates from
the plane which lies perpendicularly with respect to the axis of
rotation.
8. The hydrodynamic axial bearing as claimed in claim 7,
comprising: a second lubricating gap delimited by a planar sliding
face of the axial stop and the floating disk, the planar sliding
face of the axial stop being configured to be inclined toward the
floating disk in a manner which deviates from the plane which lies
perpendicularly with respect to the axis of rotation.
9. A turbomachine, comprising: a shaft mounted rotatably in a
bearing housing; and a hydrodynamic axial bearing for mounting the
shaft in the bearing housing, the hydrodynamic axial bearing
including: an axial stop; a bearing comb for rotating with the
shaft; and at least one lubricating gap formed between the axial
stop and the bearing comb for being loaded with lubricating oil and
delimited by a profiled circular ring face and a planar sliding
face which lies opposite the circular ring face, the profiled
circular ring face being configured so as to rotate around or with
the shaft, the profile of the circular ring face having a plurality
of segments, each segment including one radially running
lubricating oil groove, a wedge face connected to the lubricating
oil groove in a circumferential direction, and a rest face which
adjoins the wedge face in the circumferential direction, wherein,
for the at least one lubricating gap, the rest face and the planar
sliding face are configured such that the lubricating gap,
delimited by the rest face and the planar sliding face, is
constricted radially to the outside with regard to an axis of
rotation.
10. A turbomachine as claimed in claim 9, wherein the axial stop
comprises: the planar sliding face, the planar sliding face
delimiting the lubricating gap constricted radially to the outside,
the planar sliding face being configured to be inclined toward the
bearing comb at least in a radially outer part in a manner which
deviates from a plane which lies perpendicularly with respect to
the axis of rotation.
11. A turbomachine as claimed in claim 9, wherein the bearing comb
comprises: the planar sliding face, the planar sliding face
delimiting the lubricating gap constricted radially to the outside,
the planar sliding face configured to be inclined toward the axial
stop in a manner which deviates from a plane which lies
perpendicularly with respect to the axis of rotation.
12. A turbomachine as claimed in claim 9, comprising: a floating
disk arranged axially between the axial stop and the bearing comb,
the lubricating gap being formed between the floating disk and the
bearing comb.
13. A turbomachine as claimed in claim 10, comprising: a floating
disk arranged axially between the axial stop and the bearing comb,
the lubricating gap being formed between the floating disk and the
bearing comb.
14. A turbomachine as claimed in claim 11, comprising: a floating
disk arranged axially between the axial stop and the bearing comb,
the lubricating gap being formed between the floating disk and the
bearing comb.
15. A turbomachine as claimed in claim 14, wherein the floating
disk comprises: the profiled circular ring face, and the planar
sliding face of the bearing comb and the circular ring face of the
floating disk delimit the lubricating gap which is constricted
radially to the outside, the planar sliding face of the bearing
comb being configured to be inclined toward the axial stop, at
least in a radially outer part, in a manner which deviates from the
plane which lies perpendicularly with respect to the axis of
rotation.
16. A turbomachine as claimed in claim 15, a second lubricating gap
delimited by a planar sliding face of the axial stop comprising:
the floating disk, the planar sliding face of the axial stop being
configured to be inclined toward the floating disk in a manner
which deviates from the plane which lies perpendicularly with
respect to the axis of rotation.
17. An exhaust gas turbocharger, comprising: a shaft mounted
rotatably in a bearing housing; and a hydrodynamic axial bearing
for mounting the shaft in the bearing housing the hydrodynamic
axial bearing including: an axial stop; a bearing comb for rotating
with the shaft; and at least one lubricating gap formed between the
axial stop and the bearing comb for being loaded with lubricating
oil and delimited by a profiled circular ring face and a planar
sliding face which lies opposite the circular ring face, the
profiled circular ring face being configured so as to rotate around
or with the shaft, the profile of the circular ring face having a
plurality of segments, each segment including one radially running
lubricating oil groove, a wedge face connected to the lubricating
oil groove in a circumferential direction, and a rest face which
adjoins the wedge face in the circumferential direction, wherein,
for the at least one lubricating gap, the rest face and the planar
sliding face are configured such that the lubricating gap,
delimited by the rest face and the planar sliding face, is
constricted radially to the outside with regard to an axis of
rotation.
18. The exhaust gas turbocharger as claimed in claim 17, wherein
the bearing comb and the shaft are connected in a
material-to-material manner or are manufactured from one piece.
Description
RELATED APPLICATIONS
[0001] This application claims priority as a continuation
application under 35 U.S.C. .sctn.120 to PCT/EP2012/071729, which
was filed as an International Application on Nov. 2, 2012
designating the U.S., and which claims priority to German
Application 102011085681.1 filed in Germany on Nov. 3, 2011. The
entire contents of these applications are hereby incorporated by
reference in their entireties.
FIELD
[0002] The disclosure relates to the field of hydrodynamic axial
mounting of rotating shafts, as are used, for example, in
turbomachines, for example in exhaust gas turbochargers.
BACKGROUND INFORMATION
[0003] If rapidly rotating rotors are loaded with axial shearing
forces, load-bearing axial bearings can be used. For example, in
the case of turbomachines, such as exhaust gas turbochargers,
hydrodynamic axial bearings can be used to absorb axial forces,
which can be high as a result of the flow, and to guide the shaft
in an axial direction. In order to improve an oblique position
compensation capability and wear behavior in applications of this
type, disks which float freely in the lubricating oil, known as
floating disks, can be used in hydrodynamic axial bearings between
a bearing comb which rotates at the shaft rotational speed and a
non-rotating axial stop on the bearing housing. The lubricating
gaps between a rotating bearing comb and the floating disk and
between the floating disk and the stationary axial stop on the
bearing housing can be delimited in each case by a profiled
circular ring face and a plane sliding face which lies opposite the
profiled circular ring face. The profiled circular ring face can
serve to optimize the pressure build-up in the lubricating gap. The
pressure build-up can be decisive for the load-bearing force of the
axial bearing. In order to distribute the lubricating oil which is
supplied in the radially inner region of the profiled circular ring
face, there are lubricating oil grooves which lead radially to the
outside. Wedge faces, which constrict the lubricating gap in the
circumferential direction and via which the lubricating oil
introduced into the lubricating oil grooves exits, are formed
adjacently with respect to the lubricating oil grooves. Here, the
lubricating oil is guided into the wedge face as far as possible
over the entire radial height of the lubricating oil grooves. The
pressure build-up, which is desirable for the load-bearing
capability of the axial bearing, takes place substantially in the
region of the wedge faces. Rest faces, which include a planar face
and are provided by the load-bearing face of the profiled circular
ring face, are formed adjacently with respect to the wedge faces in
the circumferential direction.
[0004] Examples of axial bearings of this type are found, inter
alia, in GB 1095999, EP0840027, EP1199486, EP1644647 and EP2042753.
The radial guidance of the floating disk takes place either on the
rotating body, for example on the shaft or on the bearing comb, by
way of a radial bearing which is integrated into the floating disk,
as is disclosed, for example, in EP0840027, or else on a stationary
bearing collar which surrounds the rotating body concentrically, as
is disclosed, for example, in EP1199486. The lubrication of a
hydrodynamic axial bearing of this type can take place lubricating
oil from a dedicated lubricating oil system or, in the case of
exhaust gas turbochargers, via the lubricating oil system of an
internal combustion engine which is connected to the exhaust gas
turbocharger.
[0005] In the cold state, at a standstill, all the load-bearing
faces of known axial mountings can lie perpendicularly with respect
to the rotational axis of the rotor or else at least parallel to
one another. During operation, the load-bearing faces can be
deformed on account of temperature gradients, centrifugal, shearing
and other forces. A deformation of this type of the bearing
load-bearing faces can impair the load-bearing force of the
mounting. Temperature gradients over the comb of the comb bearing
can have particularly great effects. The comb which protrudes
radially with respect to the shaft can be deformed in an
umbrella-shaped manner on account of the temperature difference
between the load-bearing face and the rear side. This deformation
can lead to rubbing of the comb bearing on the floating disk,
particularly in the case of a low oil supply pressure. The
deformation on account of the temperature gradient can be critical
in a known comb bearing construction, because the deformation can
cause a lubricating gap which widens to the outside. This can
reduce the load-bearing capability for geometric reasons and can
reduce the centrifugal force-induced pressure build-up in the
radial direction, because the outflow resistance for the
lubricating oil radially to the outside is reduced.
SUMMARY
[0006] A hydrodynamic axial bearing for mounting a shaft mounted
rotatably in a bearing housing, the hydrodynamic axial bearing
comprising: an axial stop; a bearing comb for rotation with a shaft
when installed; and at least one lubricating gap formed between the
axial stop and the bearing comb for receiving lubricating oil, and
delimited by a profiled circular ring face and a planar sliding
face which lies opposite the circular ring face, the profiled
circular ring face being configured so as to rotate around or with
the shaft, the profile of the circular ring face having a plurality
of segments, each segment including one radially running
lubricating oil groove, a wedge face connected to the lubricating
oil groove in a circumferential direction, and a rest face which
adjoins the wedge face in the circumferential direction, wherein,
for the at least one lubricating gap, the rest face and the planar
sliding face are configured such that the lubricating gap,
delimited by the rest face and the planar sliding face, is
constricted radially to the outside with regard to an axis of
rotation.
[0007] A turbomachine is disclosed, comprising: a shaft mounted
rotatably in a bearing housing; and a hydrodynamic axial bearing
for mounting the shaft in the bearing housing, the hydrodynamic
axial bearing including: an axial stop; a bearing comb for rotating
with the shaft; and at least one lubricating gap formed between the
axial stop and the bearing comb for being loaded with lubricating
oil and delimited by a profiled circular ring face and a planar
sliding face which lies opposite the circular ring face, the
profiled circular ring face being configured so as to rotate around
or with the shaft, the profile of the circular ring face having a
plurality of segments, each segment including one radially running
lubricating oil groove, a wedge face connected to the lubricating
oil groove in a circumferential direction, and a rest face which
adjoins the wedge face in the circumferential direction, wherein,
for the at least one lubricating gap, the rest face and the planar
sliding face are configured such that the lubricating gap,
delimited by the rest face and the planar sliding face, is
constricted radially to the outside with regard to an axis of
rotation.
[0008] An exhaust gas turbocharger is disclosed, comprising: a
shaft mounted rotatably in a bearing housing; and a hydrodynamic
axial bearing for mounting the shaft in the bearing housing the
hydrodynamic axial bearing including: an axial stop; a bearing comb
for rotating with the shaft; and at least one lubricating gap
formed between the axial stop and the bearing comb for being loaded
with lubricating oil and delimited by a profiled circular ring face
and a planar sliding face which lies opposite the circular ring
face, the profiled circular ring face being configured so as to
rotate around or with the shaft, the profile of the circular ring
face having a plurality of segments, each segment including one
radially running lubricating oil groove, a wedge face connected to
the lubricating oil groove in a circumferential direction, and a
rest face which adjoins the wedge face in the circumferential
direction, wherein, for the at least one lubricating gap, the rest
face and the planar sliding face are configured such that the
lubricating gap, delimited by the rest face and the planar sliding
face, is constricted radially to the outside with regard to an axis
of rotation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] In the following text, exemplary embodiments of the
disclosure will be explained in detail using drawings, in
which:
[0010] FIG. 1 shows, in the right-hand part, a section which is
guided along the rotational axis of a known axial sliding bearing
with a rotating bearing comb, a stationary axial stop and a
floating disk, and shows, in the left-hand part, a frontal view in
the axial direction of the corresponding floating disk with a
profiled circular ring face;
[0011] FIG. 2 shows a diagrammatically illustrated axial sliding
bearing according to FIG. 1, the bearing comb being shown in each
case in the cold state in this figure and in all following figures,
and additionally the deformation of the bearing comb in the
operating state on account of the heating and the rapid rotation
and the resulting lubricating gap being indicated by way of dashed
lines;
[0012] FIG. 3 shows a diagrammatically illustrated axial sliding
bearing according to a first exemplary embodiment according to the
disclosure, with a conically shaped bearing comb and a lubricating
gap which results therefrom and tapers radially toward the
outside;
[0013] FIG. 4 shows a diagrammatically illustrated axial sliding
bearing according to a second exemplary embodiment according to the
disclosure with a floating disk which is shaped conically on the
bearing comb side and a lubricating gap which results therefrom and
tapers radially toward the outside;
[0014] FIG. 5 shows a diagrammatically illustrated axial sliding
bearing according to a third exemplary embodiment according to the
disclosure, with a conically shaped axial bearing and conically
shaped bearing comb, and two lubricating gaps which result
therefrom and taper radially toward the outside;
[0015] FIG. 6 shows a diagrammatically illustrated axial sliding
bearing according to a fourth exemplary embodiment according to the
disclosure with a conically shaped axial bearing and a floating
disk which is shaped conically on the bearing comb side, and two
lubricating gaps which result therefrom and taper radially toward
the outside;
[0016] FIG. 7 shows a diagrammatically illustrated axial sliding
bearing according to a fifth exemplary embodiment according to the
disclosure with a floating disk which is shaped conically on both
sides, and two lubricating gaps which result therefrom and taper
radially toward the outside;
[0017] FIG. 8 shows a diagrammatically illustrated axial sliding
bearing according to a sixth exemplary embodiment according to the
disclosure with a conically shaped bearing comb and a floating disk
which is shaped conically on the axial bearing side, and two
lubricating gaps which result therefrom and taper radially toward
the outside;
[0018] FIG. 9 shows a diagrammatically illustrated axial sliding
bearing according to a seventh exemplary embodiment according to
the disclosure, without a floating disk, with a conically shaped
bearing comb, and a lubricating gap which results therefrom and
tapers radially toward the outside; and
[0019] FIG. 10 shows a diagrammatically illustrated axial sliding
bearing according to an eighth exemplary embodiment according to
the disclosure, without a floating disk, with a conically shaped
axial stop, and a lubricating gap which results therefrom and
tapers radially toward the outside.
DETAILED DESCRIPTION
[0020] Exemplary embodiments of the disclosure can improve the
load-bearing capability of a hydrodynamic axial bearing for
mounting a shaft which is mounted rotatably in a bearing
housing.
[0021] If the gap, which is formed between the load-bearing faces
of the axial bearing, is configured so as to be constricted to the
outside in the radial direction, by the load-bearing faces being
arranged obliquely relative to one another at least in the radially
outer region, a reduction in the relative oblique position of the
load-bearing faces results during operation on account of the
abovementioned deformation of the rotating load-bearing face. The
constriction in the radially outer region is reduced, with the
result that the load-bearing faces can rest more uniformly on one
another during operation.
[0022] If, for example, the bearing comb is manufactured with a
conical load-bearing face, that is to say a load-bearing face which
is inclined toward the load-bearing face which lies opposite it,
the temperature deformation in the comb bearing can be compensated
for. During the compensation, the deformations on account of
centrifugal, shearing and further forces likewise have to be taken
into consideration.
[0023] Because the comb bearing deformations are dependent on the
operating point, the lubricating gap becomes smaller in the radial
direction under certain operating conditions. This situation is
more favorable than the current one with a widened lubricating gap,
because the load-bearing capability is reduced to a lesser extent
and the centrifugal force-induced pressure build-up in the radial
direction is aided.
[0024] The compensation on account of load-bearing face
deformations as a result of temperature gradients, centrifugal,
shearing and further forces can also take place at the floating
disk, or at the axial stop of the bearing housing in the case of an
axial bearing without floating disk. Any temperature-induced
deformations which occur in the region of the axial stop on the
bearing housing can be carried out in a similar way as on the comb
bearing.
[0025] If a floating disk, which is conical on both sides, or a
very thin floating disk which is adapted to changing geometric
conditions during operation, is used, the comb bearing deformation
can also be compensated for by way of a conical configuration of
the axial stop on the bearing housing.
[0026] Due to the compensation for the deformation, the axial
mounting can become more robust at the adjacent bearing parts with
respect to rubbing of the floating disk or the bearing comb, or, in
the case of an axial bearing without floating disk, of the axial
bearing. The turbocharger can become more operationally reliable
and wear-induced costs can be reduced.
[0027] FIG. 1 shows by way of example a known hydrodynamic axial
bearing, the three components of the axial bearing being made
visible in the right-hand part of the figure in a section which is
guided axially along the rotational shaft. The bearing comb 10 is
placed on the rotating shaft 40, or is optionally connected in a
material-to-material manner to the shaft, or is produced with the
shaft from one piece, and rotates with the shaft. A floating disk
30 is arranged axially between an axial stop 21 on the bearing
housing 20 and the bearing comb. In each case one lubricating gap
is formed firstly between the axial stop and the floating disk and
secondly between the floating disk and the bearing comb, in which
lubricating gap a thin lubricating oil layer is situated between
the load-bearing faces.
[0028] In an exemplary embodiment according to the disclosure, the
load-bearing face 22 on the axial stop and the load-bearing face 11
on the bearing comb in each case have a sliding face which is of
planar configuration in the circumferential direction, whereas the
two load-bearing faces of the floating disk are part of a profiled
circular ring face. This basic construction of the two lubricating
gaps is also adopted in all the exemplary embodiments described in
the disclosure of the hydrodynamic axial sliding bearings according
to the exemplary embodiment of the disclosure with a floating disk.
It applies to all these exemplary embodiments that the sliding
faces and the profiled circular ring faces in the case of one or
both of the lubricating gaps can also be arranged on the
respectively other side of the lubricating gap, with the result
that, for example, the floating disk has in each case one planar
sliding face on both sides whereas the profiled circular ring face
is attached on the load-bearing face of the bearing comb and the
axial stop of the bearing housing. In an exemplary embodiment
without a floating disk, the profiled circular ring face would
correspondingly be arranged on the rotating bearing comb and the
planar sliding face would be arranged on the axial stop of the
bearing housing or at any rate vice versa, that is to say the
planar sliding face on the rotating bearing comb and the profiled
circular ring face on the axial stop of the bearing housing.
[0029] The construction of the profiled circular ring face can be
seen from the left-hand part of FIG. 1, in which the floating disk
is rotated by 90.degree., with the result that one of the end sides
of the floating disk can be seen in a plan view.
[0030] The profiled circular ring face can optimize the pressure
build-up in the lubricating gap between the load-bearing faces,
which pressure build-up can be decisive for the load-bearing force
of the axial bearing. The profiling of the circular ring face
includes a plurality of segments with, in each case, one
lubricating oil groove 33 which is led radially to the outside in
order to distribute the lubricating oil which is supplied in the
radially inner region of the profiled circular ring face. Counter
to the rotational direction (indicated by way of the black arrow)
of the profiled circular ring face, wedge faces 34 which constrict
the lubricating gap in the circumferential direction are formed
adjacently with respect to the lubricating oil grooves 33, via
which wedge faces 34 the lubricating oil which is introduced into
the lubricating oil grooves 33 exits in accordance with the thick
arrows. Here, the lubricating oil is guided into the wedge face 34
as far as possible over the entire radial height of the lubricating
oil grooves 33. The pressure build-up, which is desirable for the
load-bearing capability of the axial bearing, takes place
substantially in the region of the wedge faces. Rest faces 35 are
formed adjacently with respect to the wedge faces 34 in the
circumferential direction, which rest faces 35 include a planar
face which is at the smallest spacing from the corresponding
contact, as the above-described sliding face. The axial extent
(thickness) of the lubricating gap can therefore be described as
the spacing between the rest faces 35 and the sliding face which
lies opposite. In order to optimize the pressure build-up in the
radial direction in the lubricating oil groove and over the wedge
faces, the lubricating oil groove and wedge face can be closed
radially to the outside by way of a web which constricts the
lubricating gap. Here, the web can come to lie as far as the height
of the rest face, with the result that the rest face and web lie in
one plane.
[0031] The configuration of the lubricating oil groove and the
wedge face is disregarded for the exemplary embodiments which are
described in the disclosure. Accordingly, the expressions of the
profiled circular ring face and the sliding face are no longer used
in the disclosure. For the practical implementation, however,
reference is made to the fact that the lubricating gaps, as
described above, are advantageously delimited in each case by a
profiled circular ring face and a planar sliding face. The
expression used in the following text of the active load-bearing
face means that region of the profiled circular ring face which can
be called a rest face. The rest faces can be situated so as to
adjoin the wedge faces as viewed in the flow direction of the
lubricating oil.
[0032] As indicated in FIG. 1 and in the detail which is shown on
an enlarged scale according to FIG. 2, in the cold state, that is
to say at a standstill of the rotor, the load-bearing faces of the
axial mountings are configured perpendicularly with respect to the
rotational axis of the rotor or else at least parallel to one
another. During operation, the load-bearing face in the bearing
comb can be deformed on account of temperature gradients,
centrifugal, shearing and further forces. The comb which protrudes
radially with respect to the shaft can be deformed in an
umbrella-shaped manner on account of the temperature difference
between the load-bearing face, which is relevant for the axial
bearing, and the rear side which faces away from the load-bearing
face. This deformation (indicated in FIG. 2 by way of dashed lines)
can lead to rubbing of the comb bearing on the floating disk in the
radially inner region, because the load-bearing force of the
lubricating gap diminishes on account of the radially outwardly
diverging load-bearing faces 31 and 11' of the axial bearing and
the associated unimpeded escape of the lubricating oil, for example
in the case of a low oil supply pressure, at which sufficient
lubricating oil cannot be replenished.
[0033] FIG. 3 shows a diagrammatically illustrated hydrodynamic
axial sliding bearing according to a first exemplary embodiment
according to the disclosure. Here, the active load-bearing face 31
on that side of the floating disk 30 which faces the bearing comb
is oriented strictly radially, that is to say perpendicularly with
respect to the rotational axis of the shaft 40. In contrast, the
load-bearing face 11 of the bearing comb is shaped so as to be
inclined toward the floating disk 30, which results in a
constriction in the axial direction in the radially outer region of
the lubricating gap 52. In this exemplary embodiment, just as in
the further exemplary embodiments which will be described in the
following text, the inclination of the load-bearing face 11 of the
bearing comb can be realized by way of a uniform, straight
inclination or by way of a curved inclination. In the figures, the
deformations of the rotating components and the constrictions of
the lubricating gaps are illustrated in a greatly exaggerated
manner. In fact, the inclination angles which are provided
according to the disclosure move over the entire radius of the
inclined component in the range of a few hundredths of a degree,
which results in a constriction of the lubricating gap at the
radially outer edge of a few hundredths of a millimeter in the case
of a disk with a diameter of 200 mm.
[0034] During operation, a deformation of the bearing comb,
indicated by way of dashed lines, can result on account of the
above-described heating of the bearing comb and as a result of the
action of the stated forces. According to the exemplary embodiment
of the disclosure, the load-bearing face 11, which is inclined
towards the floating disk in the cold state, of the bearing comb
stretches in such a way that the angle of the constriction of the
lubricating gap 52' is reduced during nominal operation and the two
load-bearing faces 31 and 11' of the bearing run parallel to one
another or, while maintaining a lubricating gap constriction which
is less pronounced than in the cold state, run at least virtually
parallel to one another. In the cold state, i.e., at a standstill
and also at small rotational speeds, the configuration according to
the exemplary embodiment of the disclosure of the axial sliding
bearing, leads to a constriction of the lubricating gap in the
radial outer region. This is not a problem, because the accumulated
lubricating oil ensures an additional pressure build-up.
[0035] FIG. 4 shows a diagrammatically illustrated hydrodynamic
axial sliding bearing according to a second exemplary embodiment
according to the disclosure. Here, the load-bearing face 11 of the
bearing comb is oriented strictly radially, that is to say
perpendicularly with respect to the rotational axis of the shaft
40. For this purpose, the load-bearing face 31 on that side of the
floating disk 30 which faces the bearing comb is configured so as
to be inclined toward the bearing comb 10 in this exemplary
embodiment, which results in the constriction in the axial
direction in the radially outer region of the lubricating gap 52.
The floating disk is therefore of conical configuration on the side
which faces the bearing comb, whereas it is oriented
perpendicularly with respect to the rotational axis of the shaft 40
on the other side which faces the axial stop on the bearing
housing.
[0036] During operation, a deformation of the bearing comb,
indicated by way of dashed lines, results on account of the
above-described heating of the bearing comb and as a result of the
action of the stated forces. The load-bearing face 11, which is
oriented perpendicularly with respect to the rotational axis of the
shaft 40 in the cold state, of the bearing comb is bent in such a
way that, during nominal operation, the angle of the constriction
of the lubricating gap 52' is reduced and the two load-bearing
faces 31 and 11' of the bearing run parallel or virtually parallel
to one another.
[0037] In the exemplary embodiments of the disclosure according to
FIGS. 5 to 8, in addition to the lubricating gap 52 between the
floating disk 30 and the bearing comb 10, the lubricating gap 51
between the axial stop 21 and the floating disk 30 can also be
configured with a constriction in the axial direction in the
radially outer region.
[0038] FIG. 5 shows a diagrammatically illustrated hydrodynamic
axial sliding bearing according to a third exemplary embodiment
according to the disclosure. Here, the load-bearing face 31 is
oriented radially on that side of the floating disk 30 which faces
the bearing comb, that is to say perpendicularly with respect to
the rotational axis of the shaft 40. In contrast, the load-bearing
face 11 of the bearing comb is shaped such that it is inclined
toward the floating disk 30, which results in a constriction in the
axial direction in the radially outer region of the lubricating gap
52. The second lubricating gap which is likewise provided with a
constriction in the axial direction in the radially outer region
extends between the load-bearing face 32 which is oriented
radially, that is to say perpendicularly with respect to the
rotational axis of the shaft 40, on that side of the floating disk
30 which faces the axial stop and the load-bearing face 22 of the
axial stop 21 on the bearing housing, which load-bearing face 22 is
inclined toward the floating disk 30. The floating disk is
therefore provided with two sides which run parallel to one another
and are oriented perpendicularly with respect to the rotational
axis of the shaft 40.
[0039] During operation, a deformation of the bearing comb 10,
indicated by way of dashed lines, results on account of the
above-described heating of the bearing comb and as a result of the
action of the stated forces. According to the disclosure, the
load-bearing face 11, which is inclined toward the floating disk in
the cold state, of the bearing comb, stretches in such a way that,
during nominal operation, the angle of the constriction of the
lubricating gap 52' is reduced and the two load-bearing faces 31
and 11' of the bearing run parallel to one another or virtually
parallel to one another.
[0040] FIG. 6 shows a diagrammatically illustrated hydrodynamic
axial sliding bearing according to a fourth exemplary embodiment
according to the disclosure, which hydrodynamic axial sliding
bearing differs from the preceding one in that the load-bearing
face 11 of the bearing comb is oriented radially, that is to say
perpendicularly with respect to the rotational axis of the shaft
40. For this purpose, the load-bearing face 31 is configured so as
to be inclined toward the bearing comb 10 on that side of the
floating disk 30 which faces the bearing comb. The second
lubricating gap, which is likewise provided with a constriction in
the axial direction in the radially outer region, extends between
the load-bearing face 32 which is oriented strictly radially, that
is to say perpendicularly with respect to the rotational axis of
the shaft 40, on that side of the floating disk which faces the
axial stop and the load-bearing face 22 of the axial stop 21 on the
bearing housing, which load-bearing face 22 is inclined toward the
floating disk 30. The floating disk is therefore of conical
configuration on the side which faces the bearing comb, whereas it
is oriented perpendicularly with respect to the rotational axis of
the shaft 40 on the other side which faces the axial stop on the
bearing housing.
[0041] During operation, a deformation of the bearing comb,
indicated by way of dashed lines, results on account of the
above-described heating of the bearing comb and as a result of the
action of the stated forces. According to the disclosure, the
load-bearing face 11 of the bearing comb, which is oriented
perpendicularly with respect to the rotational axis of the shaft 40
in the cold state, bends in such a way that, during nominal
operation, the angle of the constriction of the lubricating gap 52'
is reduced and the two load-bearing faces 31 and 11' of the bearing
run parallel to one another or virtually parallel to one
another.
[0042] FIG. 7 shows a diagrammatically illustrated hydrodynamic
axial sliding bearing according to a fifth exemplary embodiment
according to the disclosure. Here, the load-bearing face 11 of the
bearing comb is oriented radially, that is to say perpendicularly
with respect to the rotational axis of the shaft 40. In contrast,
on that side of the floating disk 30 which faces the bearing comb,
the load-bearing face 31 is configured so as to be inclined toward
the bearing comb 10, which results in a constriction in the axial
direction in the radially outer region of the lubricating gap 52.
The second lubricating gap, which is likewise provided with a
constriction in the axial direction in the radially outer region,
extends between the load-bearing face, which is oriented strictly
radially, that is to say perpendicularly with respect to the
rotational axis of the shaft 40, of the axial stop 21 on the
bearing housing and the load-bearing face 32 which is inclined
toward the axial stop on that side of the floating disk which faces
the axial stop. The floating disk 30 is therefore configured so as
to be conical on both sides.
[0043] During operation, a deformation of the bearing comb 10 which
is once again indicated by way of dashed lines, results on account
of the above-described heating of the bearing comb and as a result
of the action of the stated forces. According to the disclosure,
the load-bearing face 11, which is oriented perpendicularly with
respect to the rotational axis of the shaft 40 in the cold state,
of the bearing comb bends in such a way that, during nominal
operation, the angle of the constriction of the lubricating gap 52'
is reduced and the two load-bearing faces 31 and 11' of the bearing
run parallel to one another or virtually parallel to one
another.
[0044] FIG. 8 shows a diagrammatically illustrated hydrodynamic
axial sliding bearing according to a sixth exemplary embodiment
according to the disclosure, which hydrodynamic axial sliding
bearing differs from the preceding one in that the load-bearing
face 31 on that side of the floating disk 30 which faces the
bearing comb is oriented radially, that is to say perpendicularly
with respect to the rotational axis of the shaft 40. For this
purpose, the load-bearing face 11 of the bearing comb is shaped so
as to be inclined toward the floating disk 30, which results once
again in a constriction in the axial direction in the radially
outer region of the lubricating gap 52. The second lubricating gap
which is likewise provided with a constriction in the axial
direction in the radially outer region once again extends between
the load-bearing face 22, which is oriented radially, that is to
say perpendicularly with respect to the rotational axis of the
shaft 40, of the axial stop 21 on the bearing housing and the
load-bearing face 32 which is inclined toward the axial stop on
that side of the floating disk which faces the axial stop. The
floating disk is therefore of conical configuration on the side
which faces the axial stop on the bearing housing, whereas it is
oriented perpendicularly with respect to the rotational axis of the
shaft 40 on the other side which faces the bearing comb.
[0045] During operation, a deformation of the bearing comb,
indicated by way of dashed lines, results on account of the
above-described heating of the bearing comb and as a result of the
action of the stated forces. According to the disclosure, the
load-bearing face 11, which is inclined toward the floating disk in
the cold state, of the bearing comb stretches in such a way that,
during nominal operation, the angle of the constriction of the
lubricating gap 52' is reduced and the two load-bearing faces 31
and 11' of the bearing run parallel to one another or virtually
parallel to one another.
[0046] FIG. 9 and FIG. 10, in each case show a hydrodynamic axial
sliding bearing without a floating disk, in which a load-bearing
face 12 is arranged on the rotating bearing comb 10 and a
load-bearing face 22 is arranged on the axial stop 21 of the
bearing housing 20. According to the disclosure, the lubricating
gap 53 which results between them is configured so as to converge
radially to the outside, that is to say the lubricating gap tapers
in the radially outer region.
[0047] The seventh exemplary embodiment according to the disclosure
(shown in FIG. 9) of a hydrodynamic axial sliding bearing has a
load-bearing face 12 of the bearing comb 10, which load-bearing
face 12 is shaped so as to be inclined toward the axial stop 21 of
the bearing housing 20, which results in the constriction in the
axial direction in the radially outer region of the lubricating gap
53. The load-bearing face 22 of the axial stop 21 of the bearing
housing 20 is oriented strictly radially, that is to say
perpendicularly with respect to the rotational axis of the shaft
40, in this exemplary embodiment.
[0048] During operation, a deformation of the bearing comb,
indicated by way of dashed lines, results on account of the
above-described heating of the bearing comb and as a result of the
action of the stated forces. According to the disclosure, the
load-bearing face 12 of the bearing comb, which is inclined toward
the load-bearing face of the axial stop 21 in the cold state,
stretches in such a way that, during nominal operation, the angle
of the constriction of the lubricating gap 53' is reduced and the
two load-bearing faces 12' and 22 of the bearing run parallel to
one another or virtually parallel to one another.
[0049] The eighth exemplary embodiment according to the disclosure
(shown in FIG. 10) of a hydrodynamic axial sliding bearing has a
load-bearing face 12 of the bearing comb 10, which load-bearing
face 12 is oriented radially, that is to say perpendicularly with
respect to the rotational axis of the shaft 40. For this purpose,
in this exemplary embodiment, the load-bearing face 22 of the axial
stop 21 on the bearing housing 20 is configured so as to be
inclined toward the bearing comb 10, which results once again in
the constriction in the axial direction in the radially outer
region of the lubricating gap 53. The axial stop is therefore of
conical configuration on the side which faces the bearing comb.
[0050] During operation, a deformation of the bearing comb,
indicated by way of dashed lines, results on account of the
above-described heating of the bearing comb and as a result of the
action of the stated forces. According to the disclosure, the
load-bearing face 12 of the bearing comb 10, which is oriented
perpendicularly with respect to the rotational axis of the shaft 40
in the cold state, bends in such a way that, during nominal
operation, the angle of the constriction of the lubricating gap 53'
is reduced and the two load-bearing faces 12' and 22 of the bearing
run parallel to one another or virtually parallel to one
another.
[0051] In all the exemplary embodiments, in each case one of the
load-bearing faces is described as deviating from the plane which
is oriented perpendicularly with respect to the rotational axis of
the shaft and the other load-bearing face is described as running
radially, that is to say along a plane which is oriented
perpendicularly with respect to the rotational axis of the shaft.
According to the disclosure, the narrowing lubricating gaps can
also be realized by the respective load-bearing faces both
deviating from respective planes which are oriented perpendicularly
with respect to the rotational axis of the shaft, but being at an
angle with respect to one another. For example, in the exemplary
embodiment with a floating disk, both the load-bearing face on that
side of the floating disk which faces the bearing comb and the
load-bearing face on the bearing comb can run so as to be inclined
toward the lubricating gap in comparison with the plane which is
oriented perpendicularly with respect to the rotational axis of the
shaft, and can thus delimit the narrowing lubricating gap.
[0052] Even if in each case only load-bearing faces were mentioned
in all the above-mentioned exemplary embodiments, it is to be noted
once again here that, if one or both of the components which
delimit a respective lubricating gap have a profiled surface with a
lubricating oil groove, wedge faces and rest faces, the expression
load-bearing face means in each case that region of the profiled
surface which is called rest face. In the absence of a rest face,
the load-bearing face extends along the maximum elevation of the
wedge faces in the transition region to the respectively next
lubricating oil groove.
[0053] Thus, it will be appreciated by those skilled in the art
that the present disclosure can be embodied in other specific forms
without departing from the spirit or essential characteristics
thereof. The presently disclosed embodiments are therefore
considered in all respects to be illustrative and not
restricted.
LIST OF DESIGNATIONS
[0054] 10 Bearing comb [0055] 11, 12 Load-bearing face on the
bearing comb [0056] 11'', 12'' Load-bearing face on the bearing
comb (in the operating state) [0057] 20 Bearing housing [0058] 21
Axial stop [0059] 22 Sliding face [0060] 30 Floating disk [0061]
31, 32 Load-bearing face of the floating disk [0062] 33 Lubricating
oil groove [0063] 34 Wedge face [0064] 35 Rest face [0065] 40 Shaft
[0066] 51 Lubricating gap between the axial stop and the floating
disk [0067] 52 Lubricating gap between the floating disk and the
bearing comb [0068] 52'' Lubricating gap between the floating disk
and the bearing comb (in the operating state) [0069] 53 Lubricating
gap between the axial stop and the bearing comb [0070] 53''
Lubricating gap between the axial stop and the bearing comb (in the
operating state)
* * * * *