U.S. patent application number 13/943413 was filed with the patent office on 2013-11-14 for rotor assembly for an axial turbine.
The applicant listed for this patent is Voith Patent GmbH. Invention is credited to Patrick Hennes, Alexander Sauer.
Application Number | 20130302169 13/943413 |
Document ID | / |
Family ID | 45876665 |
Filed Date | 2013-11-14 |
United States Patent
Application |
20130302169 |
Kind Code |
A1 |
Hennes; Patrick ; et
al. |
November 14, 2013 |
ROTOR ASSEMBLY FOR AN AXIAL TURBINE
Abstract
A rotor assembly includes a drive shaft; a rotor having rotor
blades, which each comprise a profiled rotor blade section and a
blade fastening section; wherein each blade fastening section
comprises a first contact region and a second contact region, the
first contact region being at least indirectly supported on the
blade fastening section of a first adjacent rotor blade, the second
contact region being at least indirectly supported on the blade
fastening section of a second adjacent rotor blade; the blade
fastening sections are fastened in a formfitting manner and/or by a
screw connection on the drive shaft, so that there is a connection
between rotor blade and drive shaft on an axial end face of the
blade fastening section. Intermediate elements having an elastic
intermediate layer are between the blade fastening sections of
adjacent rotor blades.
Inventors: |
Hennes; Patrick;
(Herbrechtingen, DE) ; Sauer; Alexander;
(Heidenheim, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Voith Patent GmbH |
Heidenheim |
|
DE |
|
|
Family ID: |
45876665 |
Appl. No.: |
13/943413 |
Filed: |
July 16, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2012/001019 |
Mar 8, 2012 |
|
|
|
13943413 |
|
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Current U.S.
Class: |
416/170R |
Current CPC
Class: |
F03B 13/264 20130101;
Y02E 10/30 20130101; Y02E 10/20 20130101; F01D 5/02 20130101; F03D
1/0691 20130101; F03D 1/0658 20130101; Y02E 10/72 20130101; F03D
1/0666 20130101; F03B 17/061 20130101 |
Class at
Publication: |
416/170.R |
International
Class: |
F01D 5/02 20060101
F01D005/02 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 10, 2011 |
DE |
10 2011 013 547.2 |
Claims
1. A rotor assembly, comprising: a driveshaft having an assigned
axis of rotation which establishes an axial direction and a
circumferential direction, said driveshaft including an axial
terminus face; a rotor having a plurality of rotor blades each of
which includes a profiled rotor blade section and a blade fastening
section, each said profiled rotor blade section being configured
for having an incident flow in said axial direction, each said
blade fastening section including a first contact region and a
second contact region, said first contact region being at least
indirectly supported on said blade fastening section of a first
adjacent one of said plurality of rotor blades, said second contact
region being at least indirectly supported on said blade fastening
section of a second adjacent one of said plurality of rotor blades,
each said blade fastening section including an axial end face, each
said blade fastening section being fastened at least one of in a
formfitting manner and by way of a screw connection on said
driveshaft so that there is a connection between a respective one
of said plurality of rotor blades and said driveshaft on said axial
end face of said blade fastening section, said axial end face being
opposite to said axial terminus face on said driveshaft in an
installed position, each said plurality of rotor blades including a
transition from said profiled rotor blade section to said blade
fastening section, said transition having an external contour which
is free of a plurality of constrictions, said rotor including a
plurality of intermediate elements having an elastic intermediate
layer, said plurality of intermediate elements being between a
plurality of said blade fastening section of adjacent ones of said
plurality of rotor blades.
2. The rotor assembly according to claim 1, wherein said rotor
includes a segmented hub part, one of (a) said plurality of blade
fastening sections and (b) an entirety of said plurality of blade
fastening sections and said plurality of intermediate elements
forming said segmented hub part of said rotor.
3. The rotor assembly according to claim 1, wherein said first
contact region and said second contact region are each detachably
connected to said blade fastening section of an adjacent one of
said plurality of rotor blades and thereby form a plurality of
detachable connections which are implemented at least one of as a
plurality of screw connections and as a plurality of formfitting
connections.
4. The rotor assembly according to claim 1, wherein said first
contact region and said second contact region of each said blade
fastening section are respectively arranged in an intermediate
blade region of said rotor, said intermediate blade region having
angular offset in said circumferential direction to a partition
plane between adjacent ones of said plurality of rotor blades which
is at most .+-.30.degree..
5. The rotor assembly according to claim 1, wherein said plurality
of intermediate elements of said rotor are a plurality of separate
intermediate elements which are arranged spatially partitioned and
which produce a detachable connection of adjacent ones of said
plurality of blade fastening sections.
6. The rotor assembly according to claim 1, wherein, for each of
said plurality of rotor blades, an assigned said profiled rotor
blade section and an assigned said blade fastening section are
materially joined.
7. The rotor assembly according to claim 1, wherein said profiled
rotor blade section includes a first part and a second part, said
first part of said profiled rotor blade section being formed by a
blade stump, said blade stump being materially joined to each said
blade fastening section, said second part of said profiled rotor
blade section being detachably connected to said blade stump.
8. The rotor assembly according to claim 1, wherein said rotor
includes a central free region, said plurality of blade fastening
sections enclosing said central free region of said rotor.
9. The rotor assembly according to claim 8, wherein a contour of
said central free region in a rotor plane deviates from a circular
contour.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of PCT application No.
PCT/EP2012/001019, entitled "ROTOR ARRANGEMENT FOR AN AXIAL TURBINE
AND A METHOD FOR MOUNTING SAME", filed Mar. 8, 2012, which is
incorporated herein by reference.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The invention relates to a rotor assembly for an axial
turbine, in particular having a propeller-shaped rotor for a tidal
power plant or a wind power plant having horizontal axis of
rotation.
[0003] Tidal power plants having a horizontally aligned drive
shaft, which revolves on a nacelle, and which is driven by a
propeller-shaped turbine, are known and correspond to the design of
wind power plants in horizontal rotor construction. For tidal power
plants, the rotors of axial turbines of this type are either
implemented as units having free flow around them or are encased by
a jacket housing having Venturi geometry for flow acceleration. The
rotor assembly described hereafter may also be transferred to
further axial fluid-flow machines, such as fans.
[0004] For efficient energy utilization of slow currents in bodies
of water, such as continuous ocean currents or tidal currents,
large-scale rotors are required. Corresponding requirements result
in the field of wind power, in particular for offshore plants. High
forces and torques result therefrom on the region of the rotor
blade attachment at the hub, which is in rotationally-fixed
connection to the drive shaft. Correspondingly, the highly loaded
components for the rotor blade attachment must be designed with a
sufficient safety reserve for tidal power plants, since the cyclic
variations of the tidal current caused by the phase of the moon are
strongly overlaid by weather influences. Thus, depending on the
waves, the wind direction, and the existing topography on the floor
of the body of water for the respective plant location,
meteorologically influenced currents occur, which result in a
fluctuating load on the rotor.
[0005] Furthermore, a simplified plant concept having rigidly
linked rotor blades is preferable for tidal power plants because of
the accessibility for maintenance work, which is more difficult. In
many cases, a device for rotating the plant around a vertical axis
is additionally omitted and instead a rotor having rotor blades
which can have bidirectional incident flow is used. This has the
result that upon the occurrence of the overload, the rotor blades
cannot be transferred by means of a pitch angle adjustment into the
vane position, as is typically the case in the design used for wind
power plants. The entire plant also cannot be rotated out of the
current. Accordingly, a high standard results for the structural
stability of the rotor blade attachment for tidal power plants,
which results in heavy, large-scale, and expensive fastening
components.
[0006] The heretofore known rotor design for axial turbines of
tidal power plants is directed to a modularly constructed rotor,
for which the individual rotor blades are installable separately on
a hub. For this purpose, the hub has receptacles for blade
fastening sections of the rotor blades. Such blade fastening
sections are typically applied cylindrically, wherein a transition
region to the profiled rotor blade sections, which interact with
the current field, having higher structural stability is provided.
For this purpose, reference is made, for example, to WO 2010/125478
A1. The cylindrical blade fastening sections typically have a
diameter which is less than the chord length of the directly
adjoining profiled rotor blade sections and is greater than the
profile thickness in this region. There is thus a constriction,
from which a notch effect results in the event of a load of the
rotor blades, which must be secured by additional structural
reinforcements.
[0007] Furthermore, the known blade fastening sections typically
have on the hub-side end a fastening flange, which is used to form
a screw connection between the blade fastening section of the rotor
blade and the hub part of the revolving unit adjoining thereon.
Such a rotor blade fastening is disclosed for wind power plants by
U.S. Pat. No. 6,305,905 B1, for example. Corresponding fastening
flanges for rotor blades on a hub of a tidal power plant result
from GB 2467226 A, wherein a flange-shaped blade fastening section,
which is formed in one piece with the profiled rotor blade section,
is covered by means of a fastening ring for securing on the hub
part. Reference is made to U.S. Pat. No. 5,173,023 and GB 502409
for further rotor blade attachments.
SUMMARY OF THE INVENTION
[0008] The present invention is based on the object of specifying a
rotor assembly for an axial turbine having a plurality of
individually installable rotor blades, which is distinguished by a
high structural stability of the rotor blade fastenings and by an
efficient force and torque transmission to an adjoining drive
shaft. In addition, a rotor blade design is desired, which allows
simple replacement of individual rotor blades. Furthermore, the
rotor assembly is to be used in particular for operating a tidal
power plant and is preferably to be suitable for implementing an
axial turbine which can have bidirectional incident flow. The rotor
arrangement must be able to absorb in particular asymmetrical load
peaks which only act on individual rotor blades and must be
simplified both in design and manufacturing. Furthermore, an
installation method for such a rotor blade assembly is sought.
[0009] The present invention is achieved by the following features:
a rotor assembly, comprising: a driveshaft having an assigned axis
of rotation, which establishes an axial direction and a
circumferential direction; a rotor having a plurality of rotor
blades, which each comprise a profiled rotor blade section, which
can have incident flow in the axial direction, and a blade
fastening section; wherein each blade fastening section comprises a
first contact region and a second contact region and the first
contact region is at least indirectly supported on the blade
fastening section of a first adjacent rotor blade and the second
contact region is at least indirectly supported on the blade
fastening section of a second adjacent rotor blade; the blade
fastening sections are fastened in a formfitting manner and/or by
means of a screw connection on the driveshaft, so that there is a
connection between rotor blade and drive shaft on an axial end face
of the blade fastening section, which is opposite to an axial
terminus face on the driveshaft in the installed position; and for
each rotor blade, the transition from the profiled rotor blade
section to the blade fastening section has an external contour
which is free of constrictions; the invention is characterized in
that intermediate elements having an elastic intermediate layer are
provided between the blade fastening sections of adjacent rotor
blades.
[0010] The inventors have recognized that instead of fastening
individual rotor blades to a hub, the carrying capacity of a rotor
blade mount increases by omitting an integral hub component.
According to the invention, individual hub segments are assigned to
the replaceable rotor blades. These hub segments form blade
fastening sections, which mutually support one another at least in
the circumferential direction and at least indirectly.
[0011] Preferably, for rotors which can have bidirectional incident
flow, not only pressure forces in the circumferential direction
between the blade fastening sections are mediated, but rather
additionally traction forces in the circumferential direction and
axial force components are absorbed by a detachable connection of
adjacent blade fastening sections. A screw connection and/or a
formfitting connection preferably comes into consideration as the
detachable connection, so that in the event of plant maintenance,
individual rotor blades can be separately adjusted or replaced. For
an advantageous embodiment, the blade fastening sections form a
segmented hub part after the execution of the installation on the
drive shaft due to the interaction with the respective adjacent
blade fastening sections.
[0012] Each rotor blade of the rotor blade assembly according to
the invention comprises a profiled blade section and a blade
fastening section, which is preferably materially joined thereto,
and which is supported on and/or detachably connected to a
corresponding blade fastening section of an adjacent rotor. The
profiled rotor section of the rotor blades represents the part of
the rotor blade which interacts with the current field in a usable
manner. In the event of a drive by a current in a body of water,
the profiled rotor blade section is accordingly the
hydrodynamically active part of the rotor blade having an adapted
blade profile. In the case of a rotor which can have bidirectional
incident flow for a tidal power plant, symmetrical profiles are
used for this purpose, wherein an elliptical geometry can be
provided for a double-axis symmetrical profile, for example.
Alternatively, point-symmetrical profiles having a profile bulge,
i.e., reflexed trailing edge profiles, can be used.
[0013] Each rotor blade particularly preferably has a one-piece
embodiment of the assigned profiled rotor blade section and the
assigned blade fastening section. The rotor blade can be produced
from GFRP (glass fiber reinforced plastic) or CFRP (carbon fiber
reinforced plastic) material or from steel, wherein contact regions
on the blade fastening sections, which are used for force
transmission to blade fastening sections of an adjacent rotor
blade, are preferably reinforced by embedding abrasion-resistant
materials, for example, a coupling element made of metal. For a
further advantageous design, the blade fastening sections are
produced as cast parts. Profiled rotor blade sections which are
manufactured from steel, CFRP, or GFRP are materially joined
thereon.
[0014] For an alternative embodiment, blade stubs, which form a
first part of the profiled rotor blade section, are materially
joined on the blade fastening section, wherein a second part of the
profiled rotor blade section is detachably connected to the blade
stub. The transition from the first part to the second part of the
profiled rotor blade section can be embodied as an intended
breakpoint to secure the entire plant from severe destruction in
case of overload. Furthermore, the possibility exists of providing
this transition region with an elasticity to implement a
bending-rotating coupling of the rotor blade.
[0015] The blade fastening sections are fastened in a formfitting
manner and/or by means of a screw connection to a drive shaft of
the rotor assembly, so that each individual rotor blade is
connected in a rotationally-fixed manner to the drive shaft. This
connection can be conveyed through one or more of the intermediate
elements, so that the rotationally-fixed linkage of the rotor
blades is at least indirectly provided. For the rotor blade
assembly embodied according to the invention, only a part of the
forces and torques introduced from the profiled rotor blade
sections are transmitted to the respective connection of the rotor
blades to the drive shaft, since a further part of the force action
is absorbed by the mutual support of the adjacent blade fastening
sections.
[0016] For a preferred embodiment, the connection between rotor
blade and drive shaft is implemented on an axial end face of the
blade fastening section, which in the installation position is
opposite to an axial terminus face on the drive shaft. Due to the
incident flow on a rotor blade, in particular shear loads arise in
the axial direction, which result in force components in the
circumferential direction on the contact regions of adjacent blade
fastening sections. For this reason, for an advantageous embodiment
of the invention, each blade fastening section comprises a first
contact region and a second contact region as well as the
above-described third contact region to the drive shaft. The first
contact region and the second contact region are preferably
spatially partitioned. The first contact region and the second
contact region alternatively adjoin one another and merge into one
another.
[0017] The first and the second contact regions are established by
respective interaction with the directly adjacent rotor blade. For
a first embodiment, the first contact region is at least indirectly
supported on the blade fastening section of a first, directly
adjacent rotor blade and the second contact region is accordingly
at least indirectly supported on the blade fastening section of a
second, directly adjacent rotor blade. A rotor, having axial flow
from an axial direction, of an axial turbine can thus be
implemented in leeward operation. For a rotor which can have
bidirectional incident flow, which is capable of both leeward and
also windward operation, the first contact region and the second
contact region preferably have means for the detachable connection
to the respective adjoining blade fastening section of the adjacent
rotor blade. These means can be implemented in the form of a screw
connection and/or as a formfitting connection.
[0018] The contact regions are particularly preferably displaced
into the intermediate blade regions, which are less mechanically
loaded. These intermediate blade regions are thus defined in that
their angular offset in the circumferential direction to a
partition plane between adjacent rotor blades is at most
.+-.30.degree. and preferably at most .+-.15.degree.. The partition
plane extends centrally between adjacent rotor planes, which are
assigned to individual rotor blades and are respectively spanned by
the axis of rotation of the drive shaft and a further straight
line, which is characteristic for the transition from the profiled
rotor blade section to the blade fastening section. In the simplest
case, a rotor blade having a radial beam geometry is provided,
i.e., the threading lines of the profiled rotor blade sections
follow a straight line in the radial direction. For this case, a
rotor plane is established by the threading line and the axis of
rotation.
[0019] However, the case can occur that the profiled rotor blade
sections extend in a sickle shape. An embodiment is thus
conceivable for which the profiled rotor blade sections do extend
in the rotor plane which is defined as axially-symmetrical to the
axis of rotation, but the threading lines do not follow straight
lines. Furthermore, it is conceivable that the profiled rotor blade
sections are curved such that they leave the rotor plane. For such
space-occupying applied profiled rotor blade sections, a
characteristic point, for example, the point on the chord line at
half profile depth, is selected to establish the rotor plane on a
predetermined profile section in the transition from the blade
fastening section to the profiled rotor blade section. A straight
line extending through this point in the radial direction and also
the axis of rotation then define the rotor plane.
[0020] In the case of a rotor having more than three rotor blades,
the intermediate blade regions are preferably in an angular
interval of 40-60% of the angle which is formed by a section of the
rotor plane having rotor planes located adjacent to one another.
For a rotor on which substantially higher shear forces than torsion
forces act, the intermediate blade regions are less loaded in
relation to the remaining regions of the blade fastening sections.
The connecting elements for the blade fastening sections of
adjacent rotor blades advantageously lie in this region. These can
represent components which interlock in a formfitting manner, for
example, and which are fastenable to one another by a relative
movement in the axial direction of the rotor.
[0021] According to an advantageous embodiment, an elastic
intermediate layer is provided between adjoining blade fastening
sections, in particular the contact regions facing toward one
another. Elastomeric materials having a high carrying capacity,
which are typically used to implement seawater-proof plain
bearings, come into consideration for this purpose. These materials
are typically loadable with pressure and have a high abrasion
resistance for a hard/soft pair. A certain relative movement of
adjacent rotor blades, which arises because of impact loads, can be
compensated for by the elastic intermediate layer.
[0022] For a refinement, it is conceivable to mediate the
detachable connection between the blade fastening sections of
adjacent rotor blades by way of additional intermediate elements.
In contrast to the known hub components, however, these do not form
an integral structure, but rather are implemented as separate
components which are arranged spatially partitioned. For a
refinement of the invention, these intermediate elements are
capable of adapting the installation location of the rotor blades
to the respective site. This allows the use of standardized rotor
blades and a change of the rotor blade geometry, in particular the
angle of attack of the profiled rotor blade sections, by a
corresponding selection of the intermediate elements.
[0023] An embodiment is particularly preferred, for which the
entirety of the blade fastening sections of the rotor in the
fastened state encloses a central free region, which is used to
accommodate a shaft part of a driveshaft adjoining the rotor. The
contour of the central free region is particularly preferably
designed such that it deviates from the circular contour and
transmits the drive torque generated from the rotor through a form
fit with a corresponding complementarily implemented shaft
connecting part.
[0024] In addition to the displacement of the connecting elements
into the less loaded intermediate blade regions, the design
according to the invention allows the reduction of the notch effect
in the transition from the profiled rotor blade sections to the
blade fastening sections. This is achieved because the heretofore
typical cylindrical design of the blade fastening sections for
accommodation in a recess on a hub part is replaced by the
assignment of a hub segment to an individual rotor blade.
Large-scale blade fastening sections result therefrom, without the
segmented hub part, which arises due to the joining together of the
rotor blades, experiencing a size growth.
[0025] To reduce the notch effect, there are preferably no
constrictions in the region of a radial section of the rotor blade
which establishes a transition region between the profiled rotor
blade sections and the blade fastening section. A transition region
which results in a continuous tapering of the rotor blade above a
limiting radius in the direction radially outward is particularly
preferred. An alternative embodiment is also conceivable, for which
the profile regions which are essential for structural stability,
i.e., the profile lugs, protrude somewhat beyond the transverse
extension of the blade fastening section on the profiled rotor
blade section. The profile chord in this attachment region can
exceed the transverse extension of the blade fastening section by
up to 20%, without a substantial growth of the notch effect
resulting.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The above-mentioned and other features and advantages of
this invention, and the manner of attaining them, will become more
apparent and the invention will be better understood by reference
to the following description of embodiments of the invention taken
in conjunction with the accompanying drawings, wherein:
[0027] FIG. 1 shows a perspective view of a first exemplary
embodiment for a rotor assembly according to the invention in the
partially-installed state;
[0028] FIG. 2 shows a second exemplary embodiment for a rotor
assembly according to the invention in the partially-installed
state in a perspective view;
[0029] FIG. 3 shows an alternative rotor design in an axial
horizontal projection;
[0030] FIG. 4 shows a detail from FIG. 3 in an enlarged view;
[0031] FIG. 5 shows a rotor assembly according to the invention
having a rotor according to FIG. 3 in the installed state on the
driveshaft; and
[0032] FIG. 6 shows a further, alternative rotor design in an axial
horizontal projection.
[0033] Corresponding reference characters indicate corresponding
parts throughout the several views. The exemplifications set out
herein illustrate embodiments of the invention, and such
exemplifications are not to be construed as limiting the scope of
the invention in any manner.
DETAILED DESCRIPTION OF THE INVENTION
[0034] FIG. 1 shows a schematic simplified view of a rotor assembly
according to the invention having a driveshaft 1 and a rotor 20
having three rotor blades 2.1, 2.2, 2.3. The driveshaft 1 comprises
an axis of rotation 21, which establishes an axial direction 22 and
a circumferential direction 23. Each rotor blade 2.1, 2.2, 2.3
comprises a profiled rotor blade section 3.1, 3.2, 3.3 for
interacting with the current field and a blade fastening section
4.1, 4.2, 4.3. The blade fastening sections 4.1, 4.2, 4.3 are
connected in a rotationally-fixed manner to the driveshaft 1. The
boreholes 17.1, . . . , 17.n on a first axial end face 24 are used
for this purpose, which correspond with threaded boreholes 27.1, .
. . , 27.n on the axial terminus face 26 of the driveshaft 1.
[0035] For the rotor blade 2.1, the profiled rotor blade section
3.1 is materially joined to the assigned blade fastening section
4.1 for the illustrated, preferred design. The further rotor blades
2.2, 2.3 are accordingly designed such that there is a material
bond between the respective profiled rotor blade section 3.2, 3.3
and the assigned blade fastening section 4.2, 4.3. The rotor blades
2.1, 2.2, 2.3 can be produced from different construction
materials. In addition to cast parts, steel and fiber composite
materials based on GFRP and CFRP come into consideration for this
purpose. Connecting different materials to implement the rotor
blades 2.1, 2.2, 2.3 is also conceivable.
[0036] Each blade fastening section 4.1, 4.2, 4.3 comprises a first
axial end face 24 and a second axial end face 25, which are formed
by plate-shaped elements spaced apart from one another. The
plate-shaped elements are connected by a terminus plate, which
extends in the installed state in an axial sectional plane of the
driveshaft 21, at a first contact region 7.1, 7.2, 7.3 and at a
second contact region 8.1, 8.2, 8.3, so that a light-construction
but torsion-resistant structure results, which offers easy
accessibility for installation work through the side openings 32 in
the box-shaped structure.
[0037] In the installed state, the first contact region 7.1, 7.2,
7.3 for a first rotor blade 2.1, 2.2, 2.3 is opposite to the second
contact region 8.1, 8.2, 8.3 on the blade fastening section 4.1,
4.2, 4.3 of a respective directly adjacent rotor blade 2.1, 2.2,
2.3. The first contact regions 7.1, 7.2, 7.3 and the second contact
regions 8.1, 8.2, 8.3, which face toward one another in the
installed state, are used for the mutual support of the blade
fastening sections 4.1, 4.2, 4.3 in the circumferential direction
23.
[0038] For the incident flow direction 28 shown in FIG. 1, the
rotor 20 is on the leeward side. As a consequence, the resulting
shear forces 30.1, 30.2, 30.3 on the profiled rotor blade sections
3.1, 3.2, 3.3 result, in the blade fastening sections 4.1, 4.2,
4.3, in the outlined force components 29.1, 29.2 in the
circumferential direction 23, which are absorbed by mutual contact
of the blade fastening sections 4.1 and 4.3.
[0039] FIG. 2 shows a refinement of the invention for a rotor
assembly which can have bidirectional incident flow, wherein
fastening means are provided on the first contact regions 7.1, 7.2,
7.3 and the second contact regions 8.1, 8.2, 8.3, in order to
absorb the alternating compression and traction forces outlined by
the force components 29.3, 29.4. Dovetail-shaped fastening elements
10.1, . . . , 10.5 are shown as an example for this purpose, which
allow joining together of the blade fastening sections 4.1, 4.2,
4.3 by way of an axial movement of the respective rotor blade 2.1,
2.2, 2.3 relative to the already installed components. Threaded
bolts are used as an additional, detachable connection of the blade
fastening sections 4.1, 4.2, 4.3--the fastening element 6 is shown
as an example for this purpose in FIG. 2.
[0040] A further embodiment is shown in FIG. 3. This shows a
horizontal projection of the first axial end face 24 of the blade
fastening sections 4.1, 4.2, 4.3 having boreholes 17.1-17.n for
fastening on a driveshaft 1, which is outlined in FIG. 5. FIG. 4
shows the second contact region 8.2 on the blade fastening section
4.2 and the first contact region 7.3 on the blade fastening section
4.3 in an enlarged illustration as a section in the plane
established by the longitudinal axes 9.1, 9.2, 9.3 of the profiled
rotor blade sections 3.1, 3.2, 3.3. The contact regions 8.2, 7.3
are detachably connected by threaded bolts 11.1, 11.2, which
enclose and pre-tension an elastic intermediate element 13. An
elastic plain bearing material is suitable for this purpose, for
example, the elastomeric material Orkot.RTM.. The elastic
intermediate element 13 allows a certain mobility of the rotor
blades 2.1, 2.2, 2.3 in case of an asymmetrical load.
[0041] Furthermore, it is apparent from FIG. 4 that for the
illustrated preferred embodiment, a lateral opening 31 is provided
in the box-shaped blade fastening sections 4.2, 4.3, which reduces
the weight of the rotor blade attachment and allows the
accessibility to the boreholes 17.1-17.n, which are used for the
shaft attachment, for the installation.
[0042] Furthermore, FIG. 4 shows that the mutual support points of
the blade fastening sections 4.1, 4.2, 4.3 are applied in an
intermediate blade region 18.1, 18.2, 18.3 between the force
introduction regions at the transition to the profiled rotor blade
sections 3.1, 3.2, 3.3. For clarification, a partition plane 32 is
outlined between the second contact region 8.2 of the blade
fastening section 4.1 and the first contact region 7.2 of the blade
fastening section 4.2, which partition plane is at half of the
angle between the longitudinal axes 9.1 and 9.2 of the profiled
rotor blade sections 3.1, 3.2, which establish the rotor planes for
the rotor blades 2.1, 2.2 in conjunction with the surface normals
to the plane of the drawing (axial direction). Those regions which
are more weakly loaded in relation to the remaining parts of the
blade fastening sections 4.1, 4.2, 4.3 during operation of the
rotor 20 lie within an intermediate blade region 18.1, 18.2, 18.3
established by a maximum angular offset of .+-.15.degree..
[0043] A further structural reinforcement results from an
advantageous design of the transition regions 19.1, 19.2, 19.3
between the profiled rotor blade sections 3.1, 3.2, 3.3 and the
blade fastening sections 4.1, 4.2, 4.3. The advantageous embodiment
according to FIG. 3 shows an external contour which is free of
constrictions, so that the notch effect at the rotor blade
attachments is reduced. A continuous tapering from the blade
fastening section to the profiled rotor blade section 3.1, 3.2, 3.3
toward the radial outside is particularly preferably provided from
a specific radius.
[0044] In the installed state, the blade fastening sections 4.1,
4.2, 4.3 of the rotor blades 2.1, 2.2, 2.3, which are detachably
connected to one another, form a segmented hub part 5, which has a
central free region 14 for an advantageous embodiment. For the
embodiment shown in FIG. 3, the central free region 14 is
triangular in relation to a section in the rotor plane. Such a
central free region 14 of the segmented hub part 5 which deviates
from the circular shape allows, after all rotor blades 2.1, 2.2,
2.3 of the rotor 20 have been successively installed, the rotor
blades to be pushed onto a complementary shaft connecting part 16
of a driveshaft 1, with which a form fit is produced. This is shown
in FIG. 5 as a horizontal projection of the second axial end face
25 of the rotor 20. The concealed, first axial end face 24 having
the boreholes 17.1, . . . , 17.n (not visible in FIG. 5) is pressed
against the axial terminus face 26 of the driveshaft 1 for
fastening. A rotor 20 installed in this manner can be partially
installed for maintenance purposes, in that individual rotor blades
2.1, 2.2, 2.3 are separately replaced or readjusted with respect to
the relative location to the further rotor components or to the
driveshaft 1. For this purpose, it is conceivable that the
boreholes 17.1, . . . , 17.n permit a certain installation freedom
by way of the use of oblong holes. For a refinement (not shown in
detail), a securing element which is detachably connected to the
driveshaft 1 adjoins the shaft connecting part 16, which securing
element overlaps and axially secures the second axial end face 25
of the blade fastening sections 4.1, 4.2, 4.3 in the installed
position.
[0045] For the exemplary embodiment shown in FIG. 6, intermediate
elements 13.1, 13.2, 13.3 are used to implement the detachable
connection of the blade fastening sections 4.1, 4.2, 4.3. These
represent separate components which are arranged spatially
partitioned and are used to couple the rotor blades 2.1, 2.2, 2.3.
For a refinement (not shown in the figures), the intermediate
elements 13.1, 13.2, 13.3 can have a form fit with the shaft
connecting part 16 of the driveshaft 1.
[0046] In addition, an embodiment is conceivable for which
intermediate elements 13.1, 13.2, 13.3 which are adapted
specifically for the plant are used, which implement a tilted
setting of the rotor blades 2.1, 2.2, 2.3. The irregularities
resulting for this case on the end face of the rotor 20, which
faces toward the adjoining driveshaft 1, must be supported with
appropriately adapted wedge elements for secure contact.
[0047] While this invention has been described with respect to at
least one embodiment, the present invention can be further modified
within the spirit and scope of this disclosure. This application is
therefore intended to cover any variations, uses, or adaptations of
the invention using its general principles. Further, this
application is intended to cover such departures from the present
disclosure as come within known or customary practice in the art to
which this invention pertains and which fall within the limits of
the appended claims.
LIST OF REFERENCE NUMERALS
[0048] 1 driveshaft
[0049] 2.1, 2.2, 2.3 rotor blade
[0050] 3.1, 3.2, 3.3 profiled rotor blade section
[0051] 4.1, 4.2, 4.3 blade fastening section
[0052] 5 segmented hub part
[0053] 6 fastening element
[0054] 7.1, 7.2, 7.3 first contact region
[0055] 8.1, 8.2, 8.3 second contact region
[0056] 9.1, 9.2, 9.3 longitudinal axis
[0057] 10.1, . . . , 10.6 formfitting fastening element
[0058] 11.1, 11.2 threaded bolts
[0059] 12.1, 12.2, 12.3 elastic intermediate layer
[0060] 13.1, 13.2, 13.3 intermediate blade region
[0061] 14 central free region
[0062] 16 shaft connecting part
[0063] 17.1, . . . , 17.n borehole
[0064] 18.1, 18.2, 18.3 rotor blade intermediate spaces
[0065] 19.1, 19.2, 19.3 transition region
[0066] 20 rotor
[0067] 21 axis of rotation
[0068] 22 axial direction
[0069] 23 circumferential direction
[0070] 24 first axial end face
[0071] 25 second axial end face
[0072] 26 axial terminus face
[0073] 27.1, . . . , 27.n threaded boreholes
[0074] 28 incident flow direction
[0075] 29.1, 29.2,
[0076] 29.3, 29.4 force components
[0077] 30.1, 30.2, 30.3 shear forces
[0078] 31 lateral opening
[0079] 32 partition plane
[0080] 33 angular offset
* * * * *