BEARING FOR THE ROTOR OF A ROTATING MACHINE

PALIER POUR LE ROTOR D'UNE MACHINE ROTATIVE

English Abstract

The invention relates to a bearing for a rotor of a rotating machine (10),
especially a hydrogenerator which rotates around a vertically rotating axis
(11). Said bearing is embodied as a sliding bearing and comprises first means
(21, 24) for axial bearing and second means (21, 25) for radial bearing. Due
to said bearing, simplified and improved bearing properties are achieved such
that the first and second means are united to form a combined radial and axial
bearing (21) which simultaneously comprises axially sliding surfaces (24) and
radially sliding surfaces (25).

French Abstract

L'invention concerne un palier pour le rotor d'une machine rotative (10), notamment d'un hydrogénérateur tournant autour d'un axe de rotation vertical (11). Ledit palier se présente sous la forme d'un palier lisse et comprend des premiers moyens (21,24) assurant un montage sur palier axial et des deuxièmes moyens (21, 25) assurant un montage sur palier radial. L'objectif de l'invention est de simplifier ce type de palier et d'améliorer ses propriétés fonctionnelles. A cet effet, les premiers et les deuxièmes moyens sont regroupés sous la forme d'un palier radial et axial combiné (21) qui présente simultanément des surfaces de glissement axiales (24) et des surfaces de glissement radiales (25).

Claims

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WHAT IS CLAIMED IS:
1. A bearing for the rotor of a rotating machine
(10), in particular a hydrogenerator rotating
about a vertical axis of rotation (11), which
bearing is formed as a sliding bearing and
comprises a first means (21, 24) for axial
mounting and a second means (21, 25) for radial
mounting, characterized in that the first and
second means are combined to form a combined
radial and axial bearing (21), which has axial
sliding surfaces (24) and radial sliding surfaces
(25) at the same time.
2. The bearing as claimed in claim 1, characterized
in that the combined radial and axial bearing (21)
comprises a plurality of individual bearing
segments (26), which have the form of circular
ring sections and are arranged spaced apart from
one another in a ring around the axis of rotation
(11), and in that an axial sliding surface (24)
and a radial sliding surface (25) are formed on
each of the bearing segments (26).
3. The bearing as claimed in claim 2, characterized
in that each bearing segment (26) has its own
radial support (22).
4. The bearing as claimed in one of claims 1 to 3,
characterized in that the combined radial and
axial bearing (21) is arranged in an oil bath.
5. The bearing as claimed in either of claims 2 and
3, characterized in that means (29,..,32) for
supplying lubricating oil are provided in the
bearing segments (26), which lubricating oil
emerges onto the sliding surfaces (24, 25) through

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outlet openings (27, 28) in the axial and radial
sliding surfaces (24, 25).
6. The bearing as claimed in claim 5, characterized
in that, in each bearing segment (26), in the
axial sliding surface (24), there is provided a
first outlet opening (27), which has the form of
an elongated slot extending in the radial
direction and, as viewed in the direction of
rotation, is arranged at the start of the axial
sliding surface (24) , and in that in each bearing
segment (26), in the radial sliding surface (25),
there is provided a second outlet opening (28),
which has the form of an elongated slot extending
in the axial direction and, as viewed in the
direction of rotation, is arranged at the start of
the radial sliding surface (25).
7. The bearing as claimed in claim 6, characterized
in that the outlet openings (27, 28) of each
bearing segment (26) are connected to a common oil
feed bore (31) via connecting ducts (29, 30).
8. The bearing as claimed in one of claims 1 to 7,
characterized in that the rotor has a rotor shaft
(12), in that a running ring (14) surrounding the
rotor shaft (12) concentrically is fixed to the
rotor shaft (12), with which ring the rotor slides
on the axial sliding surfaces (24) of the combined
radial and axial bearing (21), and in that the
rotor with the rotor shaft (12) itself slides on
the radial sliding surfaces (25) of the combined
radial and axial bearing (21).

Description

CA 02489699 2004-12-16
DESCRIPTION
BEARING FOR THE ROTOR OF A ROTATING MACHINE
TECHNICAL FIELD
The present invention pertains to the field of rotating
machines. It relates to a bearing for the rotor of a
rotating machine according to the preamble of claim 1.
Such a bearing is known, for example from CH-A5-
651 362.
PRIOR ART
Rotors of large rotating machines, such as
hydrogenerators, are normally carried by hydrodynamic
sliding bearings. In these bearings, the axial and
radial guidance is performed by separate bearings of
different design. A partial combination of these
intrinsically separate bearings is possible inasmuch as
a running ring running in an axial bearing additionally
absorbs radial forces by radial guide segments being
arranged around said running ring. Such a
configuration, as is known from CH-A5-651 362 mentioned
at the beginning (see fig. 1 there), is reproduced in
highly simplified form in figure 1. In the rotating
machine 10' of figure l, the rotor is mounted with the
rotor shaft 12 such that it can be rotated about a
vertical axis of rotation 11. For this purpose, a
running ring 14' is fixed to the rotor shaft 12 via a
flange 13 and slides with the underside on the sliding
surface 20 of an axial bearing or supporting bearing 17
comprising individual segments (vertical arrows in
figure 1). The axial bearing 17 is in turn supported in
the axial direction by a support 18. With the outer
side, the running ring 14' slides along the sliding
surface 19 of a radial bearing or guide bearing 15

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(horizontal arrows in figure 1) . The radial bearing 15
is in turn supported in the radial direction by
supports 16.
The axial bearing 17 and the radial bearing or guide
bearing 15 function independently of one another in
this known configuration. Both bearings run in an oil
bath. The function of "carrying the rotor" is performed
by the axial bearing 17, the function of "guiding the
rotor" is performed by the guide or radial bearing 15.
Both bearings have their own segments matched to the
respective function.
In the known mounting having the separate bearing
functions, the disadvantage is that the thickness of
the running ring in the axial direction has to be
chosen to be large enough to permit the radial mounting
arranged laterally on the running ring. As a result,
the machine becomes longer overall in the axial
direction.
However, the fact that the radial mounting is placed on
the outer side of the running ring is also
disadvantageous. At this point, the circumferential
speeds are comparatively high, which leads to
correspondingly high friction losses.
Finally, separate segments have to be produced and
installed for the two bearings, which overall
considerably increases the expenditure on producing and
assembling the mounting.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a
bearing for a rotating machine which avoids the
disadvantages of known bearings and is distinguished in
particular by a simplified, space-saving construction

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and, in operation, leads to considerably reduced
friction losses.
The object is achieved by all of the features of claim
1. The core of the invention is to combine the
previously separated radial bearing and axial bearing
(or their bearing segments) to form a combined radial
and axial bearing which has axial sliding surfaces and
radial sliding surfaces at the same time. As distinct
from the prior art according to figure 1, in which,
although a common running ring for the two bearings is
fixed to the rotor, separate bearing segments are used
for the two bearings, here the two sliding surfaces are
arranged on the same bearing (or bearing segment). In
this way, a simplified, more compact construction of
the bearing is made possible, in which, at the same
time, the friction losses are reduced by means of a
skilful arrangement of the sliding surfaces.
A first preferred refinement of the invention is
characterized in that the combined radial and axial
bearing comprises a plurality of individual bearing
segments, which have the form of circular ring sections
and are arranged spaced apart from one another in a
ring around the axis of rotation, in that an axial
sliding surface and a radial sliding surface are formed
on each of the bearing segments, and in that each
bearing segment has its own radial support.
According to one alternative, the combined radial and
axial bearing is arranged in an oil bath.
Another alternative is distinguished by the fact that
means for supplying lubricating oil are provided in the
bearing segments, which lubricating oil emerges onto
the sliding surfaces through outlet openings in the
axial and radial sliding surfaces, there preferably
being provided in each bearing segment, in the axial

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sliding surface, a first outlet opening, which has the
form of an elongated slot extending in the radial
direction and, as viewed in the direction of rotation,
is arranged at the start of the axial sliding surface,
and there being arranged in each bearing segment, in
the radial sliding surface, a second outlet opening,
which has the form of an elongated slot extending in
the axial direction and, as viewed in the direction of
rotation, is arranged at the start of the radial
sliding surface. The outlet openings of each bearing
segment are preferably connected to a common oil feed
bore via connecting ducts.
The mounting according to the invention is simplified
further and is distinguished by reduced friction losses
if, according to another advantageous refinement, the
rotor has a rotor shaft, if a running ring surrounding
the rotor shaft concentrically is fixed to the rotor
shaft, with which ring the rotor slides on the axial
sliding surfaces of the combined radial and axial
bearing, and if the rotor with the rotor shaft itself
slides on the radial sliding surfaces of the combined
radial and axial bearing.
BRIEF EXPLANATION OF THE FIGURES
The invention is to be explained in more detail in the
following text by using examplary embodiments in
conjunction with the drawing, in which
figure 1 shows a mounting of a rotor of a vertical
hydrogenerator with separate radial and axial
bearing according to the prior art in a
simplified, partially longitudinally
sectioned illustration;
figure 2 shows a mounting with combined radial and
axial bearing according to a preferred

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exemplary embodiment of the invention in an
illustration comparable with figure l; and
figure 3 shows an individual bearing segment of the
mounting shown in figure 2, in which
lubricating oil is specifically supplied to
the sliding surfaces within the bearing
segment, in a perspective view in the radial
direction.
PREFERRED EMBODIMENTS OF THE INVENTION
A mounting with combined radial and axial bearing
according to a preferred exemplary embodiment of the
invention is reproduced in figure 2 in an illustration
comparable with figure 1. Identical parts are largely
designated by the same designations here. The rotating
machine 10 rotates with a rotor, of which part of the
rotor shaft 12 is shown in figure 2, about the vertical
axis of rotation 11. Fixed to the rotor shaft 12 via a
flange 13 is a running ring 14, which is used
exclusively for the axial mounting. In terms of its
axial thickness, it can therefore be reduced
considerably as compared with the running ring 14' from
figure 1.
The rotor slides with the running ring 14 on the upper,
axial (horizontal) sliding surface 24 of a combined
radial and axial bearing 21 (assembled from bearing
segments), which is in turn supported in the axial
direction by an axial support 23. The combined radial
and axial bearing 21 is extended toward the rotor shaft
12 in the radial direction to such an extent that a
radial (vertical) sliding surface 25 can be formed, on
which the rotor shaft 12 is guided. The combined radial
and axial bearing 21 is supported in the radial
direction by a radial support 22 for this purpose.
Since the radial sliding surface 25 is located very

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much further in than the radial sliding surface I9 in
the known bearing from figure 1, at the same rotational
speed the result is a very much lower circumferential
speed, which leads to lower friction losses and
therefore lower heating.
The combined radial and axial bearing 21 preferably
comprises individual bearing segments 26 according to
figure 3, which have the form of circular ring sections
and are arranged spaced apart from one another in a
ring around the axis of rotation 11 or rotor shaft 12.
An axial sliding surface 24 and a radial sliding
surface 25 are formed on each of the bearing segments
26. Each of the bearing segments 26 has its own radial
I5 support 22, whose force introduction surface is
indicated in figure 3 by a circle.
The combined radial and axial bearing 21 can in
principle be arranged in an oil bath. However, means
29,..,32 for supplying lubricating oil are preferably
provided in the bearing segments 26 according to figure
3, the lubricating oil emerging onto the sliding
surfaces 24, 25 through outlet openings 27, 28 in the
axial and radial sliding surfaces 24 and 25. In the
axial sliding surfaces 24, the means comprise a first
outlet opening 27, which has the form of an elongated
slot extending in the radial direction and, as viewed
in the direction of rotation, is arranged at the start
of the axial sliding surface 24. The lubricating oil
emerging through the slot is in this way distributed in
the form of a lubricating film on the sliding surface
24 by the bearing ring 14 sliding over the sliding
surface 24. In an analogous way, in the radial sliding
surface 25 there is provided a second outlet opening
28, which has the form of an elongated slot extending
in the axial direction and, as viewed in the direction
of rotation, is arranged at the start of the radial
sliding surface 25.

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The lubricating oil emerging from the outlet openings
27, 28 is led out from a rear connection 32 via a
radial oil feed bore 31 arranged in the interior of the
bearing segment 26 and is distributed to the outlet
openings 27, 28 via connecting ducts 29, 30. In the
comparatively long outlet opening 27, a plurality of
connecting ducts 29 distributed over the length are
provided.
The invention has been explained by using the example.
of a vertical hydrogenerator. It goes without saying
that the use of the combined radial and axial bearing
according to the invention is not restricted to
hydrogenerators of this type.
Overall, the invention results in a combined radial and
axial bearing which is specifically distinguished by
the following advantages:
- The bearing needs less space in the axial
direction. The entire machine can therefore be of
lower construction.
- The radial bearing has a smaller radius toward the
shaft. This means a lower circumferential speed
and, as a result, lower friction losses.
- Overall, fewer bearing parts are needed.

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LIST OF DESIGNATIONS
10, 10' Rotating machine (e. g. hydrogenerator)
11 Axis of rotation
12 Rotor shaft
13 Flange
14, 19' Running ring
15 Radial bearing (guide bearing)
16 Support (radial bearing)
17 Axial bearing (supporting bearing)
18 Support (axial bearing)
19 Sliding surface (radial bearing)
20 Sliding surface (axial bearing)
21 Combined radial and axial bearing
22 Radial support
23 Axial support
24 Axial sliding surface
25 Radial sliding surface
26 Bearing segment
27 Outlet opening (axial sliding surface)
28 Outlet opening (radial siding surface)
29, 30 Connecting duct
31 Oil feed bore
32 Connection

Representative Drawing