U.S. patent application number 09/790083 was filed with the patent office on 2001-09-20 for blade lock and process for manufacturing a blade lock.
Invention is credited to Zimmermamm, Achim.
Application Number | 20010022936 09/790083 |
Document ID | / |
Family ID | 7634674 |
Filed Date | 2001-09-20 |
United States Patent
Application |
20010022936 |
Kind Code |
A1 |
Zimmermamm, Achim |
September 20, 2001 |
Blade lock and process for manufacturing a blade lock
Abstract
The blades (3) of a turbine of axial design are inserted into an
undercut blade groove (2) of the turbine rotor (1) in a
positive-locking manner and are secured by a blade lock. The blade
lock comprises a mounting space (7), which is in connection with
the blade groove (2) and into which a filler piece (8), which is in
positive-locking relationship with the blade foot (6) of the blades
(3), and a wedge (9) are inserted. The cross section of the
mounting space (7) receiving the filler piece (8) is widened
conically beginning from the blade groove (2). The cross section of
the filler piece (8) is adapted to the cross section of the
mounting space (7).
Inventors: |
Zimmermamm, Achim; (Mulheim,
DE) |
Correspondence
Address: |
McGLEW AND TUTTLE, P.C.
SCARBOROUGH STATION
SCARBOROUGH STATION
SCARBOROUGH
NY
10510-0827
US
|
Family ID: |
7634674 |
Appl. No.: |
09/790083 |
Filed: |
February 21, 2001 |
Current U.S.
Class: |
416/220R ;
29/889.21 |
Current CPC
Class: |
Y10S 416/50 20130101;
F01D 5/3038 20130101; Y10T 29/49321 20150115; F01D 5/32
20130101 |
Class at
Publication: |
416/220.00R ;
29/889.21 |
International
Class: |
F01D 005/32 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 14, 2000 |
DE |
DE 100 12 381.3 |
Claims
What is claimed is:
1. A blade lock for blading an axial design turbine wherein the
blades are inserted into an undercut blade groove of a turbine
rotor in a positive-locking manner, the blade lock comprising: a
mounting space in connection with the blade groove; a filler piece
in positive-locking relationship with a blade foot of at least one
of the blades; a wedge inserted into said mounting space, said
mounting space having a cross section receiving the filler piece
that is conically widened beginning from the blade groove, said
filler piece having a cross section adapted to said cross section
of said mounting space.
2. A blade lock in accordance with claim 1, wherein said mounting
space includes side walls extending at an angle to the blade
groove.
3. A blade lock in accordance with claim 1, wherein said side walls
of said mounting space form an angle with a longitudinal axis of
the blade in an axial direction.
4. A blade lock in accordance with claim 2, wherein said side walls
of said mounting space form an angle with a longitudinal axis of
the blade in an axial direction.
5. A blade lock in accordance with claim 1, further comprising:
stud screws in the turbine rotor wherein said wedge is secured by
said stud screws in the turbine rotor.
6. A blade lock in accordance with claim 2, further comprising:
stud screws in the turbine rotor wherein said wedge is secured by
said stud screws in the turbine rotor.
7. A blade lock in accordance with claim 3, further comprising:
stud screws in the turbine rotor wherein said wedge is secured by
said stud screws in the turbine rotor.
8. A process for manufacturing a blade lock for blading an axial
design turbine wherein the blades are inserted into an undercut
blade groove of a turbine rotor in a positive-locking manner, the
blade lock including a mounting space in connection with the blade
groove, a filler piece in positive-locking relationship with a
blade foot of at least one of the blades and a wedge inserted into
the mounting space, the mounting space having a cross section
receiving the filler piece that is conically widened beginning from
the blade groove, the filler piece having a cross section adapted
to the cross section of the mounting space, the process comprising
the steps of: preparing the blade groove by turning; subsequent to
said step of preparing the blade groove by turning, inserting the
filler piece, which has been prepared except for the blade groove
contour, into the prepared mounting space; fixing the filler piece
with the wedge; milling the blade groove contour in the blade
groove and at the same time milling the blade groove contour in the
filler piece; removing the filler piece and the wedge from the
mounting space; and equipping the turbine rotor with the blades and
securing the blades in the blade groove by the blade lock.
Description
FIELD OF THE INVENTION
[0001] The present invention pertains to a blade lock for blading a
turbine of an axial design, with blades inserted into an undercut
blade groove of the turbine rotor in a positive-locking manner, the
blade groove being in connection with at least one mounting space
and where a filler piece, which is in positive-locking relationship
with a blade foot of the blades and a wedge are inserted into the
mounting space. The present invention also pertains to a process
for manufacturing a blade lock.
BACKGROUND OF THE INVENTION
[0002] A blade lock for blading turbines, in which the rotor blades
are inserted into an undercut blade groove of the turbine rotor
extending in the circumferential direction in a positive-locking
manner, has become known from DE-OS 30 28 701. At least one
mounting space, into which a filler piece which is in
positive-locking relationship with the foot of the blade is
inserted, is provided on the circumference of the turbine rotor.
The filler piece is pressed in tightly by a fitting piece, which is
driven in between the wall of the mounting space and the filler
piece. To increase the pressing force, the fitting piece is
slotted, and a wedge is pressed into the slot during the driving in
of the fitting piece into the mounting space.
[0003] In the prior-art blade lock, the pressing force acts on the
foot of the blade and consequently on the turbine rotor via the
fitting piece or the wedge. This may lead to warping and bending of
the turbine rotor if the wedge has been driven in too tightly. The
hot true running behavior of the turbine rotor may be adversely
affected during the operation of the turbine, which may lead to an
increase in the vibrations of the shaft.
SUMMARY AND OBJECTS OF THE INVENTION
[0004] The basic object of the present invention is to design the
blade lock of this type such that no pressing force is exerted on
the turbine rotor.
[0005] According to the invention, a blade lock for blading a
turbine of an axial design is provided wherein the blades are
inserted into an undercut blade groove of the turbine rotor in a
positive-locking manner. The blade groove is in connection with at
least one mounting space or mounting point and a filler piece which
is in positive-locking relationship with the blade foot of the
blades and a wedge are inserted into the mounting space. The cross
section of the mounting space receiving the filler piece is
conically widened beginning from the blade groove. The cross
section of the filler piece is adapted to the cross section of the
mounting space.
[0006] The side walls of the mounting space may be provided to
extend at an angle to the blade groove. The side walls of the
mounting space may be provided to form an angle (.alpha..sub.1,
.alpha..sub.2) with the longitudinal axis of the blade in the axial
direction. The wedge may be secured by stud screws in the turbine
rotor.
[0007] According to another aspect of the invention, a process for
manufacturing a blade lock as discussed above is provided.
According to this process, after preparing the blade groove by
turning, the filler piece, which has been prepared except for the
blade groove contour, is inserted into the prepared mounting space
and is fixed by a wedge. The blade groove contour is milled in the
blade groove and at the same time in the filler piece. The filler
piece and the wedge are removed from the mounting space. The
turbine rotor is then equipped with the blades and the blades are
secured in the blade groove by the blade lock.
[0008] The filler piece is held in the axial direction in the
mounting space designed according to the present invention such
that it is not pressed against the foot of the blade but is
supported during the wedging in the mounting space in the turbine
rotor. As a result, the warping force between the filler piece and
the wedge no longer acts on the foot of the blade, and the axial
pressing force is no longer passed through the blade groove. The
turbine rotor is not subject to axial warping. The introduction of
the blade lock cannot lead to bending of the turbine rotor during
the manufacturing process. An adverse effect of a blade lock
inserted too tightly on the hot true running behavior of the
turbine rotor is ruled out. Each blade of a blade groove including
the closing blade finds the same blade groove dimensions and
clamping conditions.
[0009] The clamping of the wedged filler piece in the mounting
space according to the present invention makes it possible to
manufacture the blade lock according to the process, in which the
contour of the groove of the filler piece and that of the blade
groove are prepared in a common work mounting. This leads to a very
high accuracy of fit of the filler piece and the wedge.
[0010] The present invention can be used generally for turbines of
axial design operating as reaction or impulse turbines for steam
turbines and process gas or tail gas turbines and especially for
blade locks for blade feet of the hammerhead or double hammerhead
design.
[0011] The various features of novelty which characterize the
invention are pointed out with particularity in the claims annexed
to and forming a part of this disclosure. For a better
understanding of the invention, its operating advantages and
specific objects attained by its uses, reference is made to the
accompanying drawings and descriptive matter in which a preferred
embodiment of the invention is illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] In the drawings:
[0013] FIG. 1 is a sectional view of a detail of a turbine
rotor;
[0014] FIG. 2 is a top view of FIG. 1;
[0015] FIG. 3 is a sectional view through a prepared blade groove
with blanks inserted; and
[0016] FIG. 4 is a top view of the prepared blade groove with
blanks inserted of FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0017] Referring to the drawings in particular, a blade groove 2
with an undercut blade groove contour is cut in the circumferential
direction into the turbine rotor 1 of a turbine of axial design.
Rotor blades 3, which comprise a blade pan 4, which passes over
into a blade foot 6 via a blade rhomboid 5, are circumferentially
inserted into the blade groove 2. A rectangle may also be
considered instead of a rhomboid. The blade feet 6 engage the blade
groove 2 with a contour corresponding to the contour of the blade
groove. This contour is designed as a double hammerhead in this
exemplary embodiment.
[0018] A mounting space or mounting region 7, via which the blades
3 are introduced into the blade groove 2, is provided at least at
one point along the blade groove 2. After the blades 3 have been
inserted, a filler piece 8 is inserted into the mounting space 7.
The filler piece 8 has a contour corresponding to that of the blade
groove contour and engages with this contour the blade foot 6 of
the blade lock. The filler piece 8 is wedged in the mounting space
7 by means of a wedge 9, which is driven into the mounting space 7
on the side of the filler piece 8 facing away from the blade 3.
[0019] The cross section of the mounting space 7 receiving the
filler piece 8 widens conically beginning from the blade groove 2.
As is shown in FIG. 2, the side walls of the mounting space 7 form
an angle .alpha..sub.1, .alpha..sub.2 with the longitudinal axis of
the blade 3. This angle is determined by the angle of the blade
rhoboid [sic-rhomboid-Tr.Ed.]. The angles may be different from one
case to the next, and they may also be different in the blade lock.
The filler piece 8 correspondingly also has two conically tapering
side surfaces adapted to the mounting space 7.
[0020] The wedge 9 which is in contact with the rear side of the
filler piece 8 is driven into the mounting space 7 to the extent
that a distance is left between the front edge of the wedge 9 and
the bottom of the mounting space 7.
[0021] The wedge 9 is secured by two stud screws 10 in the
installed state. These stud screws 10 are screwed into holes which
were prepared in the turbine rotor 1 at the contact surface between
the wedge 9 and the wall of the mounting space 7.
[0022] The parts forming the blade lock are manufactured as
follows. A rough-turned groove 2' forming the later blade groove 2
is turned in the turbine rotor 1 and the mounting space 7 is
prepared by milling. A blank 8' for the filler piece 8 and a wedge
blank 9' are inserted into the mounting space 7 and braced in the
mounting space 7 by driving in the wedge blank 9'. The blank 8' for
the filler piece 8 is prepared except for the blade groove contour.
The wedge blank 9' needs to have an overlength or a threaded hole,
so that it can again be pulled out after the finishing of the blade
lock. After inserting the blank 8' for the filler piece 8 and the
wedge blank 9', the final blade groove contour is prepared in the
turbine rotor 1 by turning. At the same time, the blade groove
contour is also prepared in the filler piece 8 by turning. After
turning the blade groove contour, the blade lock is opened by
pulling out the wedge blank 9' and removing the finished filler
piece 8, after which the turbine rotor 1 is prepared for the
blading. Before pulling out the wedge blank 9', its finished length
is marked. The wedge 9 is brought to its finished dimension before
the final insertion of the wedge 9 after the blading.
[0023] While specific embodiments of the invention have been shown
and described in detail to illustrate the application of the
principles of the invention, it will be understood that the
invention may be embodied otherwise without departing from such
principles.
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