EP2520767B1 - Gas turbine rotor balance weight - Google Patents

Description

The invention relates to a balancing device, in particular a Gasturbinenauswuchtvorrichtung, by means of which it is possible to make in the mounted state of the gas turbine balancing the intermediate or high pressure shaft.

Currently, the balancing of the high and low pressure waves takes place in different steps. First, the individual rotor drums are gewuchet. For this purpose, material is generally taken at predetermined locations on the drum. After that, the balancing of the assembled individual drums takes place. After assembling the complete engine, small corrections are then made on the low pressure shaft, e.g. by attaching weights to the freely accessible fan (fan). This is due to the lack of accessibility, not readily possible on the high pressure shaft.

The residual imbalance in the high pressure shaft and other causes can lead to vibrations and to the rejection of the engine. A method for fine balancing the high pressure shaft in the assembled engine would avoid this disadvantage, since thus occurring vibrations can be counteracted by the application of a targeted counterbalancing.

The US 5,545,010 A describes a method of incorporating or removing weights from an additionally attached ring. Accessibility is established via the gas path.

The US 4,898,514 A describes a method in which the balancing masses are mounted in axial Schaufelfußnuten. This requires a special blade standard with reduced blade root length. The accessibility is not described here.

The US 4,803,893 A describes a method in which in the disk contour of a turbine disk, an additional recess is provided in the special Balancing weights are mountable. Accessibility is not described here.

The solution according to US 5,545,010 A uses an additional ring, in which weights are installed and removed. This ring is an additional component with a relatively high weight. Furthermore, the accessibility above the annulus is possible with a modern axial compressor only at the first rotor stage. At the high pressure wave this method is not applicable.

The solution according to US 4,898,514 A is not feasible in practice, since very high voltages occur in the blade root.

All known methods are only applicable to turbine or possibly front compressor stages. A satisfactory accessibility in the assembled state of a modern axial compressor is not given or only partially possible. Balance weights can be attached only at the front or rear end of the high-pressure rotor near the bearings and partly small diameter. This is not very effective in terms of rotor dynamics and requires correspondingly massive weights. Also, all of the described methods require special additional parts and significant adjustments to the surrounding components. This is associated with corresponding weight and additional costs.

From the EP 1 726 780 A2 An arrangement for fine balancing the rotor of a gas turbine engine is known. In this case, a circumferential groove is provided, in which at a regular distance distributed circumferentially arranged insert body are fixed. Balancing is done by screwing in balancing screws into the individual insert bodies. Depending on the mass of the Balancing screws thus balancing is possible, this being limited by the arrangements and the number of individual insert body. This document discloses the subject matter of the preamble of claim 1.

The EP 1 602 855 A2 describes a balancing possibility in which an additional annular balancing element is provided, which must be additionally mounted. In this balancing element weights can be attached.

The invention has for its object to provide a gas turbine balancing device, which ensures a high degree of efficiency with a simple design and simple, reliable operation.

According to the invention the object is achieved by the feature combination of claim 1, the subclaims describe further advantageous embodiments of the invention.

According to the invention, it is thus provided that at least one annular groove extending in a radial plane to an engine axis is provided. In this at least one annular groove which is formed on the outer circumference of at least one high-pressure rotor of a high-pressure compressor, at least one balancing body is arranged. The one or more balancing body according to the invention in the circumferential direction along the annular groove slidably and fixed in the respective desired position by means of a fixing device. Preferably, several such balancing bodies are used in order to be able to produce, for example, with two balancing bodies of the same mass by displacement, a counter imbalance of any size and direction. The fixing device, which is designed for example in the form of a screw (grub screw) or the like, can be actuated by means of a tool in the installed state of the gas turbine. In this case, an access opening (borescope opening, mounting opening or the like) is particularly preferably used, so that additional adjustments of the engine housing are not or only to a limited extent required.

It is particularly advantageous if both the balancing body and the parts used for the fixing, such as screws, grub screws or the like, are designed to be captive. Thus, it is possible to perform the balancing operation, without the engine must be dismantled and without the risk that individual parts dissolve and get into the engine.

The balancing device can thus be formed in a preferred manner, without significant changes to existing components are required. The annular groove can either be additionally introduced, but it is also possible to use an already existing groove, which is used for example for air extraction, with. It is also possible to pre-install balancing weights so that they only have to be moved for fine balancing after assembly of the engine. The balancing device is thus repeatedly used and can be adjusted at any time. This proves to be particularly advantageous even if during operation of the Engine, for example, by wear or damage, imbalances occur that are to be compensated.

Fig. 1

eine schematische Darstellung eines Gasturbinentriebwerks gemäß der vorliegenden Erfindung;

Fig. 2

eine schematische Teil-Ansicht eines Ausführungsbeispiels mit eingesetztem Werkzeug;

Fig. 3

eine Ansicht, analog Fig. 2, nach erfolgter Einstellung und entferntem Werkzeug;

Fig. 4

ein weiteres Ausführungsbeispiel einer Wuchtvorrichtung; und

Fig. 5

eine Detail-Ansicht eines erfindungsgemäßen Ausführungsbeispiels der Erfindung.

Embodiments will now be described in conjunction with the drawings. Showing:

Fig. 1

a schematic representation of a gas turbine engine according to the present invention;

Fig. 2

a schematic partial view of an embodiment with inserted tool;

Fig. 3

a view, analog Fig. 2 after adjustment and removed tool;

Fig. 4

a further embodiment of a balancing device; and

Fig. 5

a detailed view of an embodiment of the invention according to the invention.

The Fig. 1 shows a schematic representation of a gas turbine engine according to the present invention.

The gas turbine engine 10 according to Fig. 1 is an example of a turbomachine to which the invention may find application. However, it will be understood from the following that the invention can be used with other turbomachinery as well. The engine 10 is conventionally formed and includes in the flow direction one after another an air inlet 11, a fan 12 circulating in a housing, an intermediate pressure compressor 13, a high pressure compressor 14, combustion chambers 15, a high pressure turbine 16, an intermediate pressure turbine 17 and a low pressure turbine 18 and an exhaust nozzle 19, which are all arranged around a central engine axis 1.

The intermediate pressure compressor 13 and the high pressure compressor 14 each include a plurality of stages, each of which includes a circumferentially extending array of fixed stationary vanes 20, commonly referred to as stator vanes, that radially inwardly from the engine casing 21 in an annular flow passage through the compressors 13, 14 protrude. The compressors further include an array of compressor blades 22 projecting radially outwardly from a rotatable drum or disc 26 coupled to hubs 27 of the high pressure turbine 16 and the intermediate pressure turbine 17, respectively.

The turbine sections 16, 17, 18 have similar stages, comprising an array of fixed vanes 23 projecting radially inward from the housing 21 into the annular flow passage through the turbines 16, 17, 18, and a downstream array of turbine blades 24 projecting outwardly from a rotatable hub 27. The compressor drum or compressor disk 26 and the vanes 22 disposed thereon and the turbine rotor hub 27 and the turbine blades 24 disposed thereon rotate about the engine axis 1 during operation.

In the following embodiments, like parts are given the same reference numerals.

The FIGS. 2 and 3 show a first embodiment. A high-pressure rotor 31 comprises a profiled annular groove 29, which extends around its circumference and in which one or more balancing bodies 30 are inserted. These are displaceable along the annular groove 29.

As especially related to Fig. 5 shown, the balancing body 30 comprises an internal thread 36, in which a clamping screw 32 (grub screw) is screwed. This can (see Fig. 5 ) be provided with a captive, for example with a foot 37, which has a larger diameter than the external thread of the clamping screw 32, so that the clamping screw 32 can not be radially turned outward.

The FIGS. 2 and 3 also show an inner housing 38, which supports stator blades 40, and an outer housing 39. Rotor blades 32 are mounted on the rotor 31 in the usual way, as known from the prior art.

The outer housing 39 has at least one access opening 35, through which a tool 33 can be inserted. The tool 33 is formed, for example in the form of a screwdriver, to rotate the clamping screw 32. To guide the tool 33, an auxiliary tool 42 is provided, which is inserted into the access opening 35 and is supported in an opening 43 of the inner housing 38 to guide the tool 33.

The Fig. 3 shows a state in the balanced, mounted state in which the tool 33 and the auxiliary tool 42 have been removed. For closing the access opening 35 and the opening 43, a closure element 34 is inserted.

The Fig. 4 shows an embodiment in which the introduction of the tool 33 is effected by a slot 44, which is provided in the inner housing 38 for air extraction and can be shared.

The Fig. 5 shows an inventive embodiment in which the annular groove 29 is formed at a joining region of two components 31a, 31b of the high-pressure rotor 31. The annular groove 29 is in communication with an air removal opening 45, for example for turbine cooling, so that, apart from the structuring of the cross section of the annular groove 29, no further changes must be performed.

The invention thus provides a groove or an annular gap in the high pressure rotor of a turbine engine, in which the groove adapted balancing body are used. The annular gap can be combined in particular with any required air withdrawals in the compressor rotor (eg for turbine cooling), as is often the case in modern compressors available. These are inventively realized by an annular gap between two bolted parts (eg, front and rear rotor drum) is formed.

The balancing bodies comprise an internal thread, in which a grub screw is screwed in to secure, which is supported against the rotor. The falling out of the screws can be prevented by a self-assurance or appropriate geometry.

For fine balancing, these balancing bodies (preferably two or more) are then displaced or rotated in the circumferential direction in order to produce a suitable counterbalance. The rotation of the balancing body takes place, for example. by retaining the same and relative rotation of the rotor.

The accessibility to hold, loosen and tighten the grub screws is ensured by the housing. To guide the assembly tool, an auxiliary tool can be used. After mounting the grub screws, the auxiliary tool and the tool are removed and the cavity is closed with a plug (closure element), so that the tightness of the inner and outer housing is ensured.

Alternatively, it is possible according to the invention to take advantage of air intake points in the housing. Through the existing slots, the tool is introduced. The use of these air intake points reduces or eliminates the complexity of the plug if the access in the outer casing is also made through the air intake points.

The radially far outward and preferably centered between the bearings position of the balancing body used is vorteihaft to compensate for the residual imbalance. Even a small change in position leads to a relatively large influence on the imbalance at comparatively low mass of the balancing body.

• Ausgleich der Restunwucht am Rotor an einer von außen nicht ohne Hilfsmittel zugänglichen Position (Turbine oder Verdichter) im zusammengebauten Zustand des Triebwerkes;
• Ausgleich von Unwuchten nach Reparaturen an Rotorschaufeln oder Ähnliches;
• Wuchten im rotordynamisch optimalen Bereich (weit außen und in der Mitte des Rotors) und daher mit geringstmöglichem zusätzlichem Gewicht;
• Minimierung zusätzlicher Bauteile und damit verbunden geringen Kosten und geringem Gewicht;
• Einfache Implementierung in existierende Triebwerke durch weitgehende Nutzung existierender oder ähnlicher Teile.

According to the invention, the following advantages thus result in particular:

• Compensation of the residual imbalance on the rotor at an externally unavailable position (turbine or compressor) in the assembled state of the engine;
• Compensation of imbalance after repairs to rotor blades or the like;
• Balancing in the rotor dynamic optimum range (far outside and in the middle of the rotor) and therefore with the lowest possible additional weight;
• Minimization of additional components and associated low costs and low weight;
• Easy implementation into existing engines through extensive use of existing or similar parts.

LIST OF REFERENCE NUMBERS

1

Engine axis

10

Gas turbine engine

11

air intake

12

in the housing revolving fan

13

Intermediate pressure compressor

14

High pressure compressor

15

combustors

16

High-pressure turbine

17

Intermediate pressure turbine

18

Low-pressure turbine

19

exhaust nozzle

20

vanes

21

Engine casing

22

Compressor blades

23

vanes

24

turbine blades

26

Compressor drum or disc

27

Turbinenrotornabe

28

outlet cone

29

ring groove

30

balancing body

31

High pressure rotor

32

clamping screw

33

Tool

34

closure element

35

access opening

36

inner thread

37

foot

38

Inner housing

39

Outer case

40

stator

41

rotor blade

42

auxiliary tool

43

opening

44

slot

45

Air discharge opening

Claims (7)

1. Gas-turbine balancing device with at least one annular groove (29) provided on the outer circumference of at least one intermediate or high-pressure rotor (31) of an intermediate or high-pressure compressor (13 or 14, respectively), with at least one balancing element (30) being arranged in the annular groove (29), said balancing element (30) being moveable in the circumferential direction along the annular groove (29), where the balancing element (30) is provided with a fixing device, characterized in that the annular groove (29) is designed at a joint region between two adjacent, bolted components (31a, 31b) of the high-pressure rotor.
2. Device in accordance with Claim 1, characterized in that at least two moveable balancing elements (30) of identical mass are arranged in the annular groove (29).
3. Device in accordance with Claim 1 or 2, characterized in that the balancing elements (30) are designed as closed rings.
4. Device in accordance with one of the Claims 1 to 3, characterized in that the annular groove (29) is designed as annular groove for tapping air from the high-pressure rotor (31).
5. Device in accordance with one of the Claims 1 to 4, characterized in that the fixing device includes at least one clamping screw (32), preferably a grub screw, which can be operated using a tool (33) that is insertable in a substantially radial direction to an engine axis (1).
6. Device in accordance with one of the Claims 1 to 5, characterized in that the fixing device is provided with a safeguard against loss.
7. Device in accordance with one of the Claims 5 or 6, characterized in that at least one access opening (35) for inserting the tool (33) can be closed by means of a closing element (34).

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