EP1698759A2 - Rotor end piece - Google Patents

Abstract

The rotor end (1) has a remaining gap which is formed between end blade (2) and an end-piece, in which the two end halves (4) are mounted at safety lugs (8) arranged therein, each as one-piece, which stay in contact with the end blade or with the end-piece. The rotor end has peripheral grooves (3) in which the rotor blades and intermediate pieces are provided. An independent claim is also included for the method for assembly of rotor end in a peripheral groove.

Description

Technical area

The invention relates to the field of thermal turbomachinery, in particular it relates to a rotor end for rotors according to the preamble of claim 1. Furthermore, an assembly method for a rotor according to the invention is given.

State of the art

Thermal turbomachinery with axial turbines and axial compressors, have a rotor equipped with blades and a stator, are mounted in the guide vanes for flow guidance.

The stationary guide vanes have the task of directing the flow of the gas medium to be compressed or to be relaxed in such a way onto the rotating running blading of the respective compressor stage or the respective turbine stage that the energy conversion takes place with the best possible efficiency.

Both blades and vanes essentially comprise a profiled airfoil and a blade root. In order to secure the blades on the rotor or the stator vanes in the stator, grooved in the stator and on the rotor shaft. In these grooves are the Feet of the blades inserted and locked there.

It is known that compressor blade rows of gas turbine rotors are arranged in circumferential grooves, which often have a T-shaped cross-section. As a rule, blades and spacers alternate here. When assembling such rows of blades, a special solution must be found for the last blades to be mounted, since then the remaining filling opening for a complete intermediate piece is too small. This residual opening is therefore filled with a so-called rotor-end.

From DE 812 337 such a rotor-end is known. The known rotor closure consists of a halved intermediate piece, that is to say of two halves divided in the circumferential direction with respect to the rotor, and a wedge with the aid of which the end halves are caulked axially in the rotor.

In the known prior art according to DE 812 337, the two end halves each have a straight lateral surface. The side surfaces mentioned are opposite in the installed state, in which case the wedge is located between them. After the two end halves and the wedge are installed, finally trained at the top of the wedge flaps are bent into corresponding undercuts in the side surfaces of the end halves and secured the wedge and thus the entire tail.

A disadvantage of this prior art that at high rotor speeds strength problems due to the tilting moment of the two end halves can occur, which is caused by the centrifugal force during operation.

Another disadvantage of these technical solutions is that the closing pieces on the one hand by the centrifugal force during operation and on the other hand exert axial forces on the rotor by caulking the wedge. In the search for the causes of the frequently occurring rotor vibrations, it has been found that these axial forces can bend the rotor and thereby disadvantageously generate disturbing vibrations.

Although EP 1 215 367 A2 and DE 103 10 432 A1 describe proposals for solutions in which the forces in the adjacent blades, i. be initiated in the circumferential direction. However, the solutions presented here are complex and expensive in assembly and manufacture.

Presentation of the invention

Object of the present invention is therefore to avoid the aforementioned disadvantages of the prior art. The invention is based on the technical problem of providing a rotor end which is as simple and inexpensive as possible during assembly and production.

According to the invention, this object is achieved by a rotor end for rotors of thermal turbomachinery with the features of patent claim 1. An inventive mounting method is described in claim 7. Advantageous embodiments and further developments of the invention are described in the subclaims.

As a result, the disadvantages of the prior art are avoided and provided a rotor end, which is simple and inexpensive to install and manufacture.

According to the invention, a rotor end for a rotor of a thermal turbomachine with at least one circumferential groove, in the rotor blades, are provided in particular with a hammer base, and intermediate pieces, characterized in that between an end blade and an end piece, a residual gap is formed, in which two end halves are arranged, each integrally with these associated locking tabs, which with the end blade or with the tail in Engage. In the solution according to the invention, no wedge is present, ie no forces are applied in the axial direction to the rotor. This is possible due to the design-related low residual gap. Due to the only two components, the assembly is very simple and inexpensive. The proposed rotor-end is safe and does not cause rotor vibrations.

An advantageous development of the invention provides that the tabs are arranged on the parting plane of the end halves. This facilitates the assembly and disassembly of the end halves.

A further advantageous development of the invention provides that the end blade and the end piece in the foot region on the side facing the remaining gap each have a recess into which the tabs of the end halves are insertable. Through the recess, the end blade and the end piece differ from the other runners and intermediate pieces. The recess may for example be designed in the shape of a cylinder segment and removed by means of a grinding tool.

Yet another advantageous development of the invention provides that the end halves have a material thickness of 3 mm to 5 mm. Hierduch manual bending of the cloth is possible with a simple assembly tool.

In addition, it has proved to be advantageous that the end halves are made of a chromium-molybdenum-vanadium alloy. This ensures the desired strength of the rotor end.

Finally, another advantageous development of the invention provides for the end halves to have relief slots underneath the tabs. This also contributes to the simple manual flexibility of the lobes and thus to the easy installation of the rotor closure. In addition, this prevents that the closing halves twist when bending the cloth.

A method according to the invention for mounting a rotor closure in a circumferential groove, which has two end halves, has the following steps: inserting the two end halves in the remaining gap, together with supports, so that the end halves are offset from one another; Inserting a tool in the parting plane between the two end halves; Bending the flaps into the recesses of the end blade and the tail; Remove the supports.

An advantageous development of the method according to the invention for mounting a rotor closure further comprises the following steps: Turning the tool through 90 °, so that the tabs protrude far enough into the recess.

Brief description of the drawings

• Fig. 1 einen Schnitt in Rotorlängsrichtung durch einen erfindungsgemässen Rotor-Schluss nach Einbau in einen Verdichterrotor;
• Fig. 2 einen teilweisen Schnitt entlang der Linie II - II aus Figur 1;
• Fig. 3 eine vergrößerte Detailansicht der beiden Schlusshälften;
• Fig. 4 eine Draufsicht auf die Schlusshälften aus Figur 3;
• Fig. 5 einen teilweisen Schnitt, der demjenigen aus Fig. 2 entspricht, jedoch mit bei der Montage eingebrachten Abstützungen.

Further advantages of the invention are illustrated below together with the description of a preferred embodiment of the invention with reference to the figures. Show it:

• 1 shows a section in the rotor longitudinal direction through a rotor according to the invention after installation in a compressor rotor.
• Fig. 2 is a partial section along the line II - II of Figure 1;
• 3 is an enlarged detail view of the two end halves.
• FIG. 4 is a plan view of the end halves of FIG. 3; FIG.
• Fig. 5 is a partial sectional view corresponding to that of Fig. 2, but with introduced during assembly supports.

The illustration in the accompanying figures is exemplary schematically. In the figures, the same components are provided with the same reference numerals. Furthermore, only the essential elements for understanding the invention are shown.

Ways to carry out the invention

FIG. 1 shows a section in the rotor longitudinal direction through a rotor end 1 according to the invention after installation in a compressor rotor 6. FIG. 2 shows a partial section along the line II - II from FIG. 1.

The remaining gap 15 present between an end blade 2 and an end piece 11 is filled by two end halves 4, 4. The flat end halves 4, 4 essentially have a cross-section which corresponds to a so-called hammer foot or two-pointed foot, with a rectangular area being excluded above the parting plane 5. At the upper, adjacent to the rectangular recess corners of the end halves 4, 4 bendable tabs 8, 8 are arranged. Below the tabs 8, 8, the closing halves 4, 4 have relief slots 10, 10.

The end blade 2 and the end piece 11 have in the foot region on the side facing the remaining gap 15 each have a recess 9, 12, in which the tabs 8, 8 of the end halves 4, 4 are introduced by bending. Through the recessed into the recesses 9, 12 tabs 8, 8 of the rotor 1 is locked and secured against falling out.

FIG. 3 shows an enlarged detail view of the two end halves 4, 4. The end halves 4, 4 face each other with their parting plane 5. Above the parting plane 5, a rectangular surface is cut out, which allows access to the two arranged on the upper edge of the parting plane 5 tabs with a tool. Below the tabs 8, 8 horizontal relief slots 10 are provided, each beginning in the parting plane 5 and terminate in a bore. The outer contour of the end halves 4, 4 is designed so that they can be inserted into a T-shaped circumferential groove 3 of a rotor 6 and find support therein.

As is apparent from Figure 4, which shows a plan view of the end halves 4, 4 of Figure 3, the end halves have only a small thickness of 3 mm to 5 mm. This makes it possible that the tabs 8,8 can still be bent manually.

FIG. 5 shows a partial section corresponding to that of FIG. 2, but with supports introduced during assembly.

After all blades and spacers and the end blade 2 and the end piece 11 are mounted in the circumferential groove 3, a residual gap 15 remains. In this residual gap 15 can only be taken from two divided in the circumferential direction of the groove 3 end halves 4, 4 existing rotor end 1 with supports 14, 14. The supports 14, 14 serve only as an assembly aid of the two 3mm to 5mm thick End halves 4, 4, which are made of a chromium-molybdenum-vanadium alloy. The supports 14, 14 are just as thick as the end halves 4, 4 or slightly thinner.

With a corresponding mounting tool 13, such as a screwdriver or a flat chisel, which is about 10 mm - 15 mm inserted into the parting plane 5 between the two end halves 4,4, the two tabs 8, 8 are bent out of the final plane.

In this case, the tool 13 is preferably rotated by 90 °, so that the lobes 8, 8 protrude far enough into the recess on the blade root 9 or into the recess on the tail base 12. The respective recesses 9, 12 are incorporated as a cylinder-segment-like recesses in the end blade foot 7 and the Endstückfuss, whereby the components differ from the other blades and spacers. Subsequently, the only required for the installation supports 14, 14 are removed and the minimum gap evenly distributed over the circumference. The final configuration achieved is shown and described in FIGS. 1 and 2.

The disassembly is carried out by drilling away or grinding away the lobes 8, 8 and removal of the end halves 4,4.

LIST OF REFERENCE NUMBERS

1

Rotor end

2

end blade

3

circumferential groove

4

final half

5

parting plane

6

rotor

7

blade root

8th

cloth

9

Recess on the blade root

10

relief slot

11

tail

12

Recess at the end piece foot

13

Tool

14

support

15

remaining gap

Claims (8)

Rotor end (1) for a rotor (6) of a thermal turbomachine with at least one circumferential groove (3) in which moving blades and intermediate pieces are provided,
characterized in that
a residual gap (15) is formed between an end blade (2) and an end piece (11), in which two end halves (4, 4) are mounted, each with securing lugs (8, 8) arranged integrally thereon, which engage with the end blade (2) or with the end piece (11) are engaged. Rotor end (1) according to claim 1,
characterized in that
the tabs (8, 8) are arranged on the parting plane (5) of the end halves (4, 4). Rotor end (1) according to claim 1 or 2,
characterized in that
the end blade (2) and the end piece (11) in the foot region on the side facing the residual gap (15) each have a recess (9, 12) into which the tabs (8, 8) of the end halves (4, 4) can be inserted , Rotor-end (1) according to one of claims 1 to 3,
characterized in that
the end halves (4,4) have a material thickness of 3 mm to 5 mm. Rotor end (1) according to one of the preceding claims,
characterized in that
the end halves (4,4) are made of a chromium-molybdenum-vanadium alloy. Rotor end (1) according to one of the preceding claims,
characterized in that
the end halves (4, 4) below the tabs (8, 8) have relief slots (10, 10). A method of assembling a rotor end in a circumferential groove having two end halves, the method comprising the steps of: - Insert the two end halves in the remaining gap, together with supports, so that the end halves are offset from each other; - Inserting a tool in the parting plane between the two end halves; - bending the tabs into the recesses of the end blade and the end piece; - Remove the supports. A rotor-mounting method according to claim 7, further comprising the steps of: - Turn the tool by 90 ° so that the tabs protrude far enough into the recess.

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