EP2818638A1 - Rotor-blade group, method and turbomachine - Google Patents

Abstract

Disclosed is a blade-disc composite (1) of a turbomachine having a plurality of juxtaposed blades (6, 8, 10) with their foot portions (12) in a circumferentially extending anchoring groove (16) of a rotor disc (4 ) and with sections (24, 26) of a front wall (18) and a rear wall (20) of the anchoring groove (16) cooperate positively in the radial direction, wherein at least one of the walls (18, 20) has a radial cutout (38). for inserting the rotor blades (6, 8, 10), wherein two rotor blades (6, 8) respectively abut against the cut-out (38) in the circumferential direction stop (46, 48) for forming two mutually opposite peripheral positive connection and between them a middle blade (10) is arranged, which is secured by at least one wire element (40) against tilting movements in the axial direction, which in the circumferential direction between the cut-out wall (20) and platform sections (36) of the rotor blades (6, 8, 10). A method for assembling such a blade-disc composite (1) and a turbomachine.

Description

The invention relates to a blade-disc composite according to the preamble of patent claim 1, a method for producing such a blade-disc composite and a turbomachine.

Known blade-disc composites in turbomachines such as gas turbines regularly have blade securing, which are often life-minimizing for the blade-disc composite itself or the entire rotor. This applies, for example, in blade fuses or securing elements in dovetail design, since this is a corresponding receiving groove is necessary, which weakens the disk structural mechanics. In embodiments with locking plates or with curved locking wires, the disadvantage is their plastic deformation for bearing fixation in the blade-disc composite. Such security elements are very expensive to assemble and disassemble and beyond reusable. In the area of plastic deformation there is the risk of stress cracks already during assembly as well as during operation under high temperature load.

In addition, created by the securing elements an additional load on the blades or the disc. For example, in the case of sheet metal fuses, there is often the problem that these loads are transmitted via edges or points in the blades and / or in the disk and thus lead to additional local voltage spikes. In any case, the introduction of loads is difficult to define and predictable. In addition, the bent safety wires have the difficulty of predicting a defined position under load. An unwanted movement or unwanted swinging of the security wires is / are not ruled out.

In the DE 10 2005 003 511 A1 there is shown a blade-disc composite in which the blades are arranged on one side on a radial collar of the disc and engage with a foot portion in a circumferential anchoring groove. The securing of the blades in the radial direction via a positive connection of the blades with the radial collar. The securing of the blades in the circumferential direction via a locking ring, the screwed to the radial collar opposite to the blades and thereby meshed with the blades.

In the GB 630732 A a blade-disc composite is shown in which the blades are arranged on both sides of a radial collar. The securing of the blades via securing wires which are inserted in receiving grooves extending in the circumferential direction and are each having a cross section in the radial collar and in the blade roots. In addition, the blade feet could interfere with foot sections in the peripheral anchoring of the radial collar form fit.

In the US 3,282,561 a blade-disc assembly is shown, in which the blades engage in a form-fitting manner in a peripheral anchoring groove of the disc and adjacent blades are connected to each other via obliquely to write extending locking pins which are inserted into corresponding blade root holes.

In the DE 10 346 263 A1 a blade-disc composite is shown in which the blades are inserted into a circumferential groove and secured only in positioning grooves securing wires are secured to the disc, each with a cross section in Nutwandungen and the blade roots.

In the DE 10 2004 051 116 A1 a blade-disc composite is shown, in which the blades engage in a form-fitting manner in a peripheral anchoring groove of the disc. In the radial direction, the blades are secured via the positive connection with the anchoring groove. In the circumferential direction adjacent blades are secured by longitudinal pins which are inserted into corresponding Nutwandungen.

The object of the invention is to provide a blade-disc composite comprising an alternative blade guard and easy to assemble and disassemble. Furthermore, it is an object of the invention to provide a method for assembling such a blade-disc composite and a turbomachine.

This object is achieved by a blade-disc composite having the features of patent claim 1, by a method having the features of patent claim 8, and by a turbomachine having the features of patent claim 10.

An inventive blade-disk composite of a turbomachine has a plurality of juxtaposed blades, which are used with their foot sections in a peripheral anchoring a rotor disc and with sections of a front wall and a rear wall of the anchoring groove in the radial direction positively cooperate. According to the invention, at least one of the walls has at least one radial cutout for insertion of the rotor blades, two blades resting against a stop limited to the cutout in the circumferential direction to form two mutually opposite circumferential interlocking connections and a middle blade is arranged between them through at least one wire element secured against tilting movements in the axial direction that extends in the circumferential direction between the cut-out wall and platform portions of the blades.

In the blade-disk assembly according to the invention, in particular life-time-minimizing securing elements are dispensed with. The inventive type of constructive the blades are in the radial, axial direction and circumferentially positively and non-positively secured to the disc. The securing of the blades in the radial direction via the positive connection of their foot sections with the wall sections of the anchoring groove. The securing of the blades in the circumferential direction is effected by the lateral stops or lateral boundaries of the cutouts in cooperation with at least two blades. The securing of the blades in the axial direction and thus securing the middle blades takes place by the at least one wire element. With the help of this at least one wire element whose installation is possible by slight elastic deformation, creates a positive connection for the entire blade-disc composite. At the same time can be used by the nature of the structural design reusable serving as security elements wire elements at low cost and maintenance intervals. The at least one wire element is held by the construction according to the invention stress-free in the blade-disc composite. In operation, it is located on a large area at boundary surfaces of the blade-disc composite. This does not create any additional edges or point loads or the associated voltage spikes. An assembly of the at least one wire element takes place without plastic deformation or screwing, whereby undefined material stresses are avoided by deformation and thus possible cracks. Thus, the blade-disc composite according to the invention is substantially more temperature-resistant than conventional blade-disc composites with plastically deformed securing elements.

Preferably, the at least one wire element is inserted into a receiving groove which is formed in the rotor blades and / or at the end of the rotor disk. Such a receiving groove can be easily trained.

In order to prevent slippage of the at least one wire element in the circumferential direction, the at least one middle blade and / or the rotor disc can have a receiving groove-side limiting section for fixing the position of the at least one wire element in the circumferential direction. As a result, the limiting section is arranged in the region of the respective cutout, so that its position relative to the limiting section can be checked visually easily without aids.

To form the mutually opposite form-fitting connections in the circumferential direction, the blades may have laterally of the central blade a platform-side axial downgrading to rest against the stops. Such a platform-side downgrading is technically easy to perform. In addition, individual blade groups are thereby formed in a plurality of cutouts, which are each secured in the circumferential direction.

In a preferred embodiment, a plurality of cutouts are provided in at least one of the walls, a plurality of receiving grooves and a plurality of wire elements. The wire elements lie in each case with their ends on two nearest middle blades. As a result, each blade is secured by two wire elements against tilting movements, so that even in the unlikely event of failure of one of the wire elements, the affected middle blade is secured by the other wire elements against tilting movements in the axial direction. The number of grooves and the Wire elements preferably depend on the number of cutouts and are preferably identical to these.

The assembly of the at least one wire element can be simplified if the at least one wire element or the wire elements are in particular bent according to the course of the at least one receiving groove. In this way, the at least one wire element can be easily inserted into the at least one receiving groove.

Likewise, the assembly can be simplified if the at least one wire element is straight and the receiving grooves are inclined to the rotor disk.

In a method according to the invention for mounting a blade-disc composite according to the invention, first a rotor disk with a circumferential anchoring groove is provided, wherein at least one radial cut-out is made in at least one of the two groove walls. Then the blades are inserted individually into the anchoring groove in the region of the at least one cutout. Thereafter, the at least one wire element is inserted in the circumferential direction in a receiving groove between blade platforms and the cut-out wall.

An assembly of the at least one wire element takes place without plastic deformation or screwing, whereby undefined material stresses are avoided by deformation and thus possible cracks. The at least one wire element is only slightly elastically deformed for mounting and relaxes after insertion into the receiving groove. The at least one wire element is held by the construction according to the invention stress-free in the blade-disc composite. Thus, the blade-disc composite according to the invention is substantially more temperature-resistant than conventional blade-disc composites with plastically deformed securing elements.

In addition, the lack of plastic deformation allows easy, fast and reproducible assembly and disassembly or securing and unlocking of the blades. In particular, by eliminating the plastic deformation, the at least one wire element can be reused.

In a preferred method, a plurality of cutouts are provided in at least one of the walls, wherein in each cutout three blades are assigned to the cutouts. In each case, a first blade is inserted into the anchoring groove in the region of a cutout and displaced up to a stop in the circumferential direction. Then, a second blade is inserted into the anchoring groove in the region of the cutout and moved in a direction opposite to the opposite direction to a counter-stop. Subsequently, a third blade is inserted into the anchoring groove in the region of the cutout. Then, a wire element is inserted into the respective receiving groove and this out with its ends in each case on two next middle blades. This embodiment simplifies the assembly due to the multiplicity of cut-outs, since a visual control of the wire elements in the receiving grooves can take place virtually over the entire circumference of the pane. In addition, blade groups are formed, which are each secured in the circumferential direction.

A turbomachine according to the invention, such as a gas turbine and in particular an aircraft engine, has at least one blade-disk assembly according to the invention. The blade-disc composite can be arranged on the compressor side and / or on the turbine side, so that a turbomachine with a large number of such blade-disc composites is distinguished by a highly resilient rotor.

Other advantageous embodiments of the invention are the subject of further subclaims.

Figur 1

eine Vorderansicht eines Abschnitts eines erfindungsgemäßen Schaufel-Scheiben-Verbundes,

Figur 2

eine Rückansicht des Schaufel-Scheiben-Verbundes,

Figur 3

einen Längsschnitt durch den Schaufel-Scheiben-Verbund,

Figur 4

eine perspektivische Rückansicht des Schaufel-Scheiben-Verbundes,

Figur 5

die Rückansicht des Schaufel-Scheiben-Verbundes aus Figur 2, und

Figur 6

eine weitere perspektivische Rückansicht des Schaufel-Scheiben-Verbundes.

In the following preferred embodiments of the invention will be explained in more detail with reference to schematic representations. Show it:

FIG. 1

a front view of a portion of a blade-disc composite according to the invention,

FIG. 2

a rear view of the blade-disc composite,

FIG. 3

a longitudinal section through the blade-disc composite,

FIG. 4

a perspective rear view of the blade-disc composite,

FIG. 5

the rear view of the blade-disc composite out FIG. 2 , and

FIG. 6

another perspective rear view of the blade-disc composite.

As in the front view in FIG. 1 and in the rear view in FIG. 2 1, a blade-disk composite 1 according to the invention of a turbomachine has a blade row 2 and a rotor disk 4. The front view corresponds to a plan view in the axial flow direction of a hot gas flowing through the turbomachine. The rear view thus corresponds to an upstream view or an axial view opposite to the flow direction. The turbomachine is, for example, a gas turbine and in particular an aircraft engine. The blade-disc composite 1 forms part of a rotor which rotates about an axial axis of rotation. The rotor is a turbine rotor in the illustrated embodiment, but may also be a compressor rotor. The blade row 2 consists of a plurality of in the circumferential direction of the blade-disc composite 1 juxtaposed blades 6, 8, 10. For reasons of clarity, only three blades 6, 8, 10 of the blade row 2 are numbered. The blades 6, 8, 10 are as in axial section in FIG. 3 shown on the blade 8, each with its foot 12 and its neck 14 received in a circumferential anchoring groove 16 of the rotor disk 4.

The anchoring groove 16 has a front wall 18 viewed in the flow direction and a rear wall 20, which are connected to one another via a groove base 22. To secure the blades 6, 8, 10 in the radial direction, the walls 18, 20 have two opposite annular beads 24, 26 against which the blades 6, 8, 10 with their widened compared to their necks 14 feet 12 in operation in the radial direction. From the groove bottom 22, the blades 6, 8, 10 are always spaced with their feet 12.

The blades 6, 8, 10 extend upstream with a front platform portion 28 over the front wall 18 and terminate flush with a radially extending end face 30 of the front wall 18. In the resting state are the Blades 6, 8, 10 with their front platform sections 28 each on a peripheral surface 32 of the front wall 18 and are spaced in operation over a small radial gap therefrom. As in FIG. 1 As shown, the front wall 18 is circumferentially formed with a uniform height so that all the blades 6, 8, 10 have the same front platform portion 28.

Between rear platform sections 36 of the rotor blades 6, 8, 10 and the rear wall 20, which, as shown in FIG FIG. 2 has a plurality of radial cutouts 38, in the embodiment shown here in each case a wire element 40 for securing the respective circumferentially centered in the cutouts 38 blade 10 is inserted against axial tilting movements. The respective wire element 40, which will be explained in more detail below, is inserted in each case a receiving groove 42 which in the embodiment shown here in sections in a bottom 44 of the rear platform sections 36 and the respective cutout 38 laterally bounding radial projections 46, 48 of the rear Wall 20 is introduced. The projections 46, 48 are in FIG. 2 quantified. Preferably, the wire element 40 and the receiving groove 42 have a corresponding circular cross-section.

As in FIG. 2 1, the blade-disc composite 1 described here by way of example has a large number of cut-outs 38, to each of which three rotor blades 6, 8, 10 are assigned. For clarity, only a section 38 is numbered representative of all sections. The rotor blades 6, 8, 10 are each associated with a cutout 38 such that one of the rotor blades 10, as already mentioned above, is arranged centrally in the circumferential direction of the cutout 38 and the two other rotor blades 6, 8 are arranged laterally of the middle blade 10.

The lateral blades 6, 8 form sections a circumferential overlap with the projections 46, 48 and are thereby secured against axial tilting. To form the overlaps, the lateral blades 6, 8 as in FIG. 4 shown in each case a lateral and axial downgrading 50, 52 in their rear platform section 36. In the assembled state, the projections 46, 48 of the rear wall 20 engage in each one of the downgrades 50, 52 and form with these two mutually opposite positive-locking connections, so that the blades 6, 8, 10 as a single 3-groups in Circumferential direction on the rotor disk 4 are secured in position. The projections 46, 48 thus act as a stop and Gegenanaschlag for the two lateral blades 6, 8 of the blade group.

As in the FIG. 5 Each wire element 40, 40 'extends between two adjacent cutouts 38, 38' and thus over a projection 48. They each extend over two adjacent lateral rotor blades 6, 8 'away and terminate at the end on two next middle rotor blades 10, 10'. The wire elements 40, 40 'effect, in particular in cooperation with the front wall 18, a securing of the middle moving blades 10, 10' against tilting movement in the axial direction, whereby in each case two adjacent wire elements 40, 40 'with their opposite end sections 54, 56' one of the middle blade 10 is guided, this is secured against tilting movements even in the unlikely event of failure of one of the wire elements 40, 40 '. In order to secure the wire elements 40, 40 'in the circumferential direction against slipping, the middle blades 10, 10' as well as in FIG. 6 shown in each case a receiving groove-side limiting section 58, 58 'on which the wire elements 40, 40' with their opposite end portions 54, 56 'abut the front side or nearly abut. To simplify their assembly, the wire elements 40, 40 'are preferably bent in the circumferential direction and thus trace the bending of the receiving grooves 42. The receiving grooves 42 thus extend in the embodiment shown here via two adjacent lateral blades 6, 8 'and end on two next middle blades 10, 10'.

In a preferred method for assembling the blade-disk assembly 1, the rotor disk 4 is first provided with a plurality of radial cutouts 38. Then, the blades 6, 8, 10 are inserted into the anchoring groove 16. For this purpose, the first lateral blade 6 is tilted or rotated in the middle of the cutout 38 in the anchoring groove 16. The lateral blade 6 is then moved in the circumferential direction until it rests with its front platform portion 28 on the projection 48 of the rotor disk 4. Then the circumferentially opposite second lateral blade 8 is tilted or rotated centrally of the cutout 36 in the anchoring groove 16 of the rotor disk 4 and displaced in the opposite direction to the projection 46 until it engages in its decrement 52. Thereafter, the middle blade 10 is centered in the cutout 38 between the side blades 6, 8 tipped into the anchoring groove 16. Thereafter, in the region of an adjacent cutout 38 ', the rotor blades 6', 8 ', 10' are inserted into the anchoring groove 16.

As soon as two cutouts 38, 38 'are provided with their moving blades 6, 8, 10 or 6', 8 ', 10', a wire element 40 is inserted into the receiving groove 42 extending on the two middle moving blades 10, 10 ', in that they abut the front side on the receiving groove-side limiting sections 58, 58 'of the middle moving blades 10, 10'. The assembly of the wire element 40 takes place in each case from the outside by lateral insertion into the receiving grooves 42 in the circumferential direction until it is present at an end portion 54 on the limiting section 58. For this purpose, the wire element 40 is slightly elastically deformed in each case. The other end portion 56 of the wire member 40 then snaps into the receiving groove 42 over its entire length and sets the front end on the limiting portion 58 'of the next middle blade 10' a. This process is repeated until all blades 6, 8, 10 or 6 ', 8', 10 'are used.

The disassembly of the respective wire element 40 is performed in reverse order. Here, the wire members 40 are slightly elastically deformed and then can be pulled outward in the circumferential direction. In order to easily lift the wire elements 40 out of the anchoring groove 42, a corresponding recess is provided in the receiving grooves 42 and / or in the wire elements 40.

If only one cutout is provided instead of a plurality of cutouts 38, then all the rotor blades 6, 8, 10 are inserted into the anchoring groove 16 via a tilting or rotary movement in the region of the cutout 36. After inserting all the blades 6, 8, 10, a wire member 40 is inserted in the circumferential direction in a receiving groove 42 in the circumferential direction. After insertion of the wire member 40 in the circumferentially extending receiving groove 42, the end portions 54, 56 of the single wire member 40 are disposed on the last used or single central blade 10 and spaced from each other via a limiting portion 58 of the central blade 10. In order to enable insertion of the blades into the anchoring groove 16, which are arranged completely between the walls 18, 20 and thus outside of the cutout 38, these have a shortened front platform section 28. The two Side of the middle blade 10 arranged lateral blades 6, 8 are each provided with a front platform side downgrading 50, 52 for cooperation with the lateral, the cutout bounding projections 46, 48 for securing the blade row 2 in the circumferential direction.

In the figures, the wire elements 40 and the cutouts 36 are arranged in the region of the rear wall 20. Of course, they can also be arranged in the region of the front wall 18 or on both walls 18, 20.

Of course, the cutouts 38 may also have such an extent in the circumferential direction that they are assigned more than three blades 6, 8, 10. For example, blade groups with four, five, six or more blades are also possible, so that two, three, four or more middle blades 10 per cutout 38 are provided.

Disclosed is a blade-disk assembly of a turbomachine having a plurality of juxtaposed blades which are inserted with their root portions in a circumferentially extending anchoring groove of a rotor disc and cooperate with sections of a front wall and a rear wall of the anchoring groove in the radial direction positively wherein at least one of the walls has a radial cut-out for insertion of the blades, wherein two blades each abut against a stopper bounding the cut-out in the circumferential direction for forming two mutually opposite circumferential interlocking connection and between them a middle blade is arranged by at least one wire element secured against tilting movements in the axial direction, which extends in the circumferential direction between the cut-out wall and platform portions of the blades. a method for assembling such a blade-disc composite and a turbomachine.

LIST OF REFERENCE NUMBERS

1

Scoop laminated composite

2

blade row

4

rotor disc

6

blade

8th

blade

10, 10 '

blade

12

foot

14

neck

16

anchoring groove

18

front wall

20

rear wall

22

groove base

24

torus

26

torus

28

front platform section

30

front

34

peripheral surface

36

rear platform section

38, 38 '

neckline

40

wire element

42

receiving groove

44

bottom

46

head Start

48

head Start

50

downgrading

52

downgrading

54

end

56, 56 '

end

58, 58 '

limiting portion

Claims (10)

Blade-disc composite (1) of a turbomachine, with a plurality of juxtaposed blades (6, 8, 10), which are inserted with their foot sections (12) in a circumferential anchoring groove (16) of a rotor disc (4) and with sections (24, 26) of a front wall (18) and a rear wall (20) of the anchoring groove (16) cooperate positively in the radial direction, characterized in that at least one of the walls (18, 20) has a radial cutout (38) for insertion of the Blades (6, 8, 10), wherein two blades (6, 8,) in each case on a cutout (38) in the circumferential direction limiting stop (46, 48) for forming two mutually opposite circumferential positive connection and abut between them a middle Blade (10,) is secured by at least one wire member (40) against tilting movements in the axial direction, extending in the circumferential direction between the cut Wall (20) and platform portions (36) of the rotor blades (6, 8, 10) extends. Blade-disc composite according to claim 1, wherein the at least one wire element (40) is inserted into a receiving groove (42) which is formed in the rotor blades (6, 8, 10) and / or in the rotor disc (4). A blade-disc composite according to claim 1 or 2, wherein said at least one middle blade (10) and / or said rotor disc (4) has a receiving groove-side confining portion (58) for fixing the at least one wire member (40) circumferentially. A blade-disc composite according to claim 1, 2 or 3, wherein the lateral blades (6, 8) have a platform-side axial downgrade (50, 52) for engagement with the stops (46, 48). A blade-disc composite according to any one of the preceding claims, wherein a plurality of cutouts (38) in at least one of the walls (18, 20), a plurality of Receiving grooves (42) and a plurality of wire elements (40) are provided, which are guided with their ends (54, 56) respectively on two adjacent next blades (10, 10 '). Blade-disc composite according to one of the preceding claims, wherein the at least one wire element (40) is pre-bent. Blade-disk composite according to one of claims 1 to 5, wherein the at least one wire element (40) is straight and the at least one receiving groove obliquely to the rotor disk (4) are employed. Method for mounting a blade-disc composite (1) according to one of the preceding claims, comprising the steps: - Providing a rotor disk (4) with a peripheral anchoring groove (16), wherein in at least one of the two walls (18, 20) at least one radial cutout (38) is introduced, - Inserting the blades (6, 8, 10) in the anchoring groove (16) in the region of the at least one cutout (38), and - Inserting at least one wire element (40) in the circumferential direction in a receiving groove (42) between blade platforms (28, 36) and the cut-out wall (20). Method according to Claim 8, in which at least one of the walls (18, 20) has a multiplicity of cutouts (38) and in each case three blades (6, 8, 10) are assigned to the cutouts (38), wherein a respective first blade ( 6) in the anchoring groove (16) in the region of a cutout (38) is inserted and is displaced up to a stop (48) in the circumferential direction, a second blade (8) inserted into the anchoring groove (16) in the region of the cutout (38) is moved and in a circumferential direction to a counter-stop (46), a third blade (10) in the anchoring groove (16) in the region of the cutout (38) is inserted, and in each case a wire element (40) in the respective receiving groove (42 ) is inserted, which is guided with its ends (54, 56) respectively on two adjacent middle blades (10, 10 '). Turbomachine with a blade-disc composite (2) according to one of claims 1 to 7.

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