EP3236011B1 - Rotor with overhang on rotor blades for a securing element - Google Patents

Description

The invention relates to a rotor for an engine, in particular a gas turbine engine according to the preamble of claim 1.

the EP 2 873 807 A1 and EP 2 860 350 A1 disclose known rotors according to the preamble of claim 1.A generic and example from U.S. 5,256,035 A known rotor has a rotor base part, which has attachment points for rotor blades arranged one behind the other along a circumferential direction about an axis of rotation. The individual rotor blades are each held in a form-fitting manner in an associated fastening groove via a blade root. For axial securing with respect to the axis of rotation, a one-part or multi-part securing element is provided, which is positively held on at least one of the rotor blades on a radially outer edge and on the rotor base part on a radially inner edge.

In the U.S. 5,256,035 For example, a multi-part securing element is provided, which consists of several plate segments and a fastening ring. A radially inner edge of the individual plate segments is positively received in a groove of the rotor base part, so that a radially outwardly extending overhang of the rotor base part encompasses the radially inner edge of the plate segments. The fastening ring is in turn accommodated in a groove which is formed in each case on a blade base of a rotor blade. In this case, one encompasses itself radially inward extending overhang of the vane base the radially outer edge of the mounting ring over which also secures a plate segment disposed adjacent and axially adjacent the mounting ring.

With a view to the individual overhangs of the several rotor blades connected to the rotor base part, however, undesirable turbulence can occur in the area of two adjacent overhangs during operation of the rotor, especially in the case of a rapidly rotating and highly loaded rotor, such as that in a gas turbine engine, for example in the high-pressure compressor or the high-pressure turbine is used. This is based on the Figures 5A , 5B , 5C and 5D illustrated in more detail, each showing a rotor known from the prior art in sections.

The rotor here comprises a rotor base part in the form of a rotor disk 2 with a plurality of fastening grooves 20 spaced apart from one another along a circumferential direction U. A blade root 32 of a rotor blade 3a, 3b is accommodated in each fastening groove 20. Of the plurality of blades, which are arranged along the circumference of the rotor in a row (for example 20 pieces) are in the Figures 5A , 5B , 5C and 5D only two of them are shown in detail with a view along the axis of rotation of the rotor. Each rotor blade 3a, 3b comprises a blade base 31 from which a blade 30 protrudes radially. The blade root 32 extends from the blade base 31 in the radially inward direction ri.

The blade base 31 of a moving blade 3a or 3b in each case forms an overhang 310 which extends radially inward, ie along the radial direction ri pointing towards it. A radially outer edge 43 of a securing plate 4 is surrounded by this overhang 310 . A plurality of (at least two) rotor blades 3a and 3b are secured in the axial direction on the rotor base part 2 in the region of the fastening grooves 20 via this securing plate 4 . For this purpose, the securing plate 4 is connected not only to the rotor blades 3a and 3b, but also to the rotor base part 2. For a form fit between the rotor base part 2 and the locking plate 4 while enclosing in the Figures 5A to 5C non-illustrated overhang of the rotor base part 2 has a radially inner edge 42 of the securing plate 4. The elongate securing plate 4, which extends in the circumferential direction, is thus held both at its radially outer edge 43 and at its radially inner edge 42 and is accommodated in a groove which is formed by a moving blade 3a, 3b or the rotor base part 2.

How in particular based on the Figure 5A As can be seen, a rotating blade 3a, 3b known from the prior art forms an overhang 310 for encompassing the radially outer edge 43 of the securing plate 4, which over an entire length L along the circumferential direction U is formed as a continuous edge 311 running in a straight line or in the shape of a circular arc . Along the circumferential direction U, their respective overhangs 310 of adjacent edges 311 should therefore be aligned with one another on a pair of moving blades 3a and 3b arranged adjacent to one another, so that the radially inner lower edges of these edges 311 lie on a circular path around the axis of rotation M of the rotor.

In practice, however, this is often not the case Figures 5B and 5C illustrate. Because of the tolerances to be allowed, it is possible for the individual overhangs 310 of mutually adjacent moving blades 3a, 3b to be offset radially with respect to one another. the Figures 5B and 5C show an example of an offset g of the two rotor blades 3a and 3b in the area of their overhangs 310. In the variant of Figure 5B the one (left) moving blade 3b is offset radially inwards compared to the adjacent (right) moving blade 3a. Relative to an axis of rotation of the rotor about the axis of rotation M along the circumferential direction, one overhang 310 of one rotor blade 3b thus protrudes into an annular gap flow in the circumferential direction U (offset “into the wind”). In the variant of Figure 5C one (left) rotor blade 3b is offset radially outwards relative to the other (right) rotor blade 3a (offset “out of the wind”). The edge 311 of the overhang 310 of one rotor blade 3b is thus completely offset radially outwards relative to the overhang 310 of the other rotor blade 3a.

An offset g that can be observed in practice for both cases is only in the range of 0.2 mm to 0.4 mm for a rotor. However, in the case of high-speed rotors for a gas turbine engine, for example a rotor of a high-pressure turbine or a high-pressure compressor, undesired turbulence can occur in the area of adjoining blade bases 31 and thus adjoining overhangs 310 .

The object of the invention is to improve a rotor in this regard.

This object is achieved with a rotor of claim 1.

According to the invention, a rotor is proposed with a specially designed overhang on at least one moving blade which is positively connected to the rotor base part. The overhang has two, first and second, edge sections along its extent in the circumferential direction, which are each provided at one end of the overhang, based on the circumferential direction, and each opposite at least one further, third edge section of the overhang, which also encompasses the edge of the securing element are set back in a radially outward direction in such a way that the blade root and a lower edge of the overhang can be pushed through the gap in the rotor base part when the securing element is not yet or no longer attached.

Consequently, the overhang of at least one rotor blade in a rotor according to the invention is set back or set back at a lower edge of the overhang in the radially outward direction such that the overhang at a radially inner lower edge does not have a straight line or arc-shaped course along the circumferential direction. This includes in particular the formation of an edge section with a radial offset to an adjacent edge section of the same overhang as well as the formation of an edge section whose radial extension in the circumferential direction steadily decreases and thus defines an area of the lower edge of the overhang that runs obliquely to the circumferential direction. On a radially inner lower edge of an overhang, regions are thus formed, for example, which are offset radially with respect to one another and/or run at an angle with respect to one another. A recess is thus defined from the outset, preferably in the area of adjacent overhangs. This can lead to the minimization or avoidance of disruptive turbulence in the area of the securing element, particularly with appropriate dimensioning. Furthermore, a weight reduction can be achieved in this way, as well as a simplification in the assembly and/or disassembly of a rotor blade. The latter in that the at least one recessed edge section can be designed and arranged along the circumferential direction in such a way that at least part of the overhang can be pushed through the fastening groove in the axial direction when the securing element is not yet or no longer fixed to the rotor base part.

At least one of the first and second radially outwardly recessed edge sections may have a smaller extension in the radially inward direction than an adjacent edge section. The overhang thus extends radially inward to a lesser extent in the region of the recessed edge section. At least one of the first and second radially outwardly recessed edge portions is provided at a circumferential end of the overhang in one embodiment. In this way, a defined recess is provided via the recessed edge section in that area at which two mutually adjacent moving blades abut with their blade bases.

In one exemplary embodiment, at least one of the first and second radially outwardly recessed edge sections forms an area on the radially inner lower edge of the overhang, which runs at least partially inclined with respect to the circumferential direction. Consequently, the recessed edge section can not only be set back in stages to an adjoining edge section of the overhang, but also form a setback that is continuously increasing or decreasing at least in sections in the circumferential direction.

It has been shown that for specific applications and in particular speeds of the rotor, a specific minimum size for the radially outwardly directed retraction of the edge section of a rotor blade overhang is advantageous in order to reduce turbulence. In this context, one exemplary embodiment provides that the at least one edge section that is recessed radially outwards extends along the circumferential direction of the rotor with a length that corresponds to at least three times, in one variant at least four times, a height of the height that is recessed radially outwards Edge portion relative to an adjacent edge portion of the overhang (at least) is withdrawn. At a minimum height b, with which the at least one edge section is set back radially outwards compared to an adjacent edge section of the overhang, i.e. radially in the outward-pointing direction, and a length a, with which the at least one set back edge section extends along the circumferential direction extends, this consequently means that: a ≥ 3b.

Alternatively or additionally, the at least one edge section that is set back radially outwards is set back by at least a height of 0.5 mm, in particular at least by a height of 0.8 mm or 1 mm, compared to an adjoining edge section of the rotor blade overhang. A recess is thus formed over the recessed edge section, which has a maximum depth of at least 0.5 mm, 0.8 mm or 1 mm when two adjacent moving blades are nominally aligned.

In one variant, the overhang of a rotor blade of the rotor can have two edge sections, namely a first and a second edge section, which are each set back in a radially outward-pointing direction compared to at least one further third edge section of the overhang, which also encompasses the edge of the securing element. The first edge section and the second edge section are thus spatially separated from one another and spaced apart from one another along the circumferential direction, but each is set back radially outwards relative to at least a third edge section of the moving blade overhang.

In this case, the two recessed edge sections can be recessed to different extents and/or can extend along the circumferential direction with different lengths from one another. The overhang of a moving blade can thus be configured asymmetrically with respect to a radial direction. This enables, for example, a configuration of a recess that is optimized in terms of the direction of rotation, which is formed by two edge sections of two adjacent rotor blades that are adjacent to one another and are each set back radially outwards.

In particular, with a view to such a variant, it can be provided that the first and second edge sections of a rotor blade, which are set back radially outwards, are provided on ends of the associated overhang (and a blade base of the associated rotor blade) that are spaced apart from one another along the circumferential direction. Along the circumference of the rotor, a second edge portion of one (first) blade overhang and a first edge portion of another (second) blade overhang thus adjoin adjacent blades and blade bases. In this way, overhangs can be provided on at least two moving blades of the rotor which are arranged adjacent to one another along the circumferential direction, with edge sections which adjoin one another and are each set back radially outwards. In this way, a radially outwardly directed recess of a defined minimum length and minimum height is then formed in the region of the border sections of two adjacent rotor blades that adjoin one another. At the radial recess, an interruption of a circular course of the edges of the individual overhangs that follow one another along the circumferential direction is thus provided in a targeted manner.

In a variant, at least one of the first and second radially outwardly recessed edge portions is opposite the adjacent third edge portion of the rotor blade overhang is reduced by at least the sum of the shape and position tolerances of this third edge section. A recess is thus formed via a recessed first or second edge section, which has a maximum (radial) depth of at least the sum of the shape and position tolerances of the third edge section when two adjacent moving blades are nominally aligned. A nominal position of the third edge section with respect to the associated fastening groove and/or with respect to an overhang of an adjacent moving blade of the rotor is predetermined via the shape and position tolerances.

A recess defined in the area of the blade bases of two adjacent moving blades is elliptical, trapezoidal or triangular in a view along the axis of rotation, for example.

Along the circumferential direction of the rotor, overhangs with adjacent edge sections that are set back radially outward can be provided on each pair of moving blades arranged adjacent to one another, so that along the circumferential direction in the area of adjoining edge sections of two adjacent moving blades there is a radially outwardly directed recess of a defined minimum length and minimum height is formed. In this variant, the formation of a recess is therefore not limited to individual pairs of moving blades, but is provided continuously in each area of two adjacent moving blades.

At least one of the first and second edge sections set back radially outwards can be produced, for example, by mechanical material removal. This includes production by means of a machining manufacturing process, such as grinding or milling. In such a variant, material can consequently be removed in a targeted manner on the overhang of a rotor blade base, for example ground off, in order to achieve that a radially inner lower edge of the overhang no longer has a straight course.

Alternatively, an edge section set back radially outwards can be produced by thermal material removal. For example, it can be provided in this connection that the production takes place by means of eroding. This includes production by spark erosion, as a result of which a recessed edge section can be produced comparatively easily even subsequently on an overhang made of high-strength material. It can be provided that the (thermal) removal of material on the overhang to produce a recessed edge section in takes place in one operation with the production of specific functional areas on a rotor blade. For example, it is common for a functional area, such as a damper pocket or a blade base area provided with at least one cutout to reduce weight, to be produced on a moving blade in the area of the blade base by eroding. In such a work step, the overhang of a rotor blade can then also be processed accordingly in order to provide an edge section that is set back radially outwards.

In principle, the at least one securing element can be provided for axially securing at least two rotor blades. In this case, a preferably plate-shaped securing element is surrounded at a (radially outer) edge by the overhangs of at least two rotor blades.

The accompanying figures illustrate exemplary possible embodiment variants of the invention.

Figur 1A

ausschnittsweise einen erfindungsgemäß ausgestalteten Rotor mit Blick entlang einer Rotationsachse des Rotors auf zwei abschnittsweise radial nach außen zurückgenommene Überhänge zweier benachbarter Laufschaufeln des Rotors;

Figur 1B

in mit der Figur 1A übereinstimmender Ansicht einen radialen Versatz zwischen zwei Schaufelbasen der benachbarten Laufschaufeln gegenüber der in der Figur 1A dargestellten nominellen Ausrichtung der beiden Laufschaufeln zueinander;

Figur 1C

in mit der Figur 1A übereinstimmender Ansicht den Rotor unter teilweiser Ausblendung eines Sicherungselements zur Veranschaulichung eines Schaufelhalses einer Laufschaufel, der in eine Befestigungsnut eingeschoben ist;

Figur 1D

eine Laufschaufel in Einzeldarstellung;

Figur 2A

in mit den Figuren 1A und 1B übereinstimmender Ansicht eine weitere Ausführungsvariante mit geometrisch unterschiedlich ausgestalteten zurückgenommenen Randabschnitten an zwei Überhängen zweier Laufschaufeln;

Figur 2B

in mit der Figur 1C übereinstimmender Ansicht den Rotor der Figur 2A;

Figur 3

eine Schnittdarstellung längs der Rotationsachse eines erfindungsgemäß ausgestalteten Rotor im eingebauten Zustand in ein Gasturbinentriebwerk;

Figur 4

ausschnittsweise eine entlang einer Schnittlinie parallel zur Rotationsachse des Rotors gewonnene Schnittdarstellung des Rotors;

Figuren 5A - 5D

jeweils ausschnittsweise ein aus dem Stand der Technik bekannter Rotor mit zwei benachbarten Laufschaufeln, deren Überhänge mit einem geradlinig verlaufenden Rand und damit nominell miteinander fluchtenden Unterkanten (Figur 5A) sowie gegebenenfalls toleranzbedingt zueinander versetzten Unterkanten (Figuren 5B und 5C) sowie unter teilweiser Ausblendung eines Sicherungselements (Figur 5D) dargestellt sind;

Figur 6

in Schnittdarstellung schematisch ein Gasturbinentriebwerk, in dem ein erfindungsgemäßer Rotor Verwendung findet.

Show it:

Figure 1A

detail of a rotor designed according to the invention with a view along an axis of rotation of the rotor to two overhangs of two adjacent moving blades of the rotor, which overhangs are recessed radially outwards in sections;

Figure 1B

in with the Figure 1A matching view, a radial offset between two blade bases of the adjacent rotor blades compared to that in FIG Figure 1A illustrated nominal alignment of the two blades to each other;

Figure 1C

in with the Figure 1A matching view of the rotor with partial omission of a securing element to illustrate a blade neck of a rotor blade, which is inserted into a fastening groove;

Figure 1D

a blade in detail;

Figure 2A

in with the Figures 1A and 1B matching view another variant with geometrically differently designed recessed edge sections on two overhangs of two rotor blades;

Figure 2B

in with the Figure 1C agreeing view the rotor of Figure 2A ;

figure 3

a sectional view along the axis of rotation of a rotor designed according to the invention in the installed state in a gas turbine engine;

figure 4

a detail of a sectional view of the rotor obtained along a cutting line parallel to the axis of rotation of the rotor;

Figures 5A - 5D

in each case a detail of a rotor known from the prior art with two adjacent rotor blades, the overhangs of which have an edge running in a straight line and thus lower edges that are nominally aligned with one another ( Figure 5A ) as well as lower edges offset from one another due to tolerances ( Figures 5B and 5C ) and with partial hiding of a security element ( Figure 5D ) are shown;

figure 6

a schematic sectional view of a gas turbine engine in which a rotor according to the invention is used.

the figure 6 FIG. 12 illustrates, schematically and in a sectional view, a (gas turbine) engine T, in which the individual engine components are arranged one behind the other along a central axis or axis of rotation M. At an inlet or intake E of the engine T, air is sucked in along an entry direction E by means of a fan F. This fan F is driven by a shaft, which is rotated by a turbine TT. Here, the turbine TT is connected to a compressor V, which has, for example, a low-pressure compressor 11 and a high-pressure compressor 12, and possibly also a medium-pressure compressor. On the one hand, the fan F supplies air to the compressor V and, on the other hand, to a bypass channel B for generating the thrust. The air conveyed via the compressor V finally reaches a combustion chamber section BK, in which the drive energy for driving the turbine TT is generated. For this purpose, the turbine TT has a high-pressure turbine 13 , a medium-pressure turbine 14 and a low-pressure turbine 15 . The Turbine TT operates via the The energy released during combustion turns on the fan F, in order to then generate the required thrust via the air conveyed into the bypass duct B. The air leaves the bypass channel B in the area of an outlet A at the end of the engine T, where the exhaust gases from the turbine TT flow to the outside. In this case, the outlet A usually has a thrust nozzle.

In particular, in the area of the high-pressure turbine 13, at least one rotor comes with the introduction in connection with the Figures 5A to 5D configuration shown for use. The rotor is arranged and rotatably mounted about the central axis or axis of rotation M in such a way that the individual securing plates 4 provided along the circumferential direction U for axially securing the rotor blades 3a, 3b are arranged on a downstream end face of the rotor 2. The individual securing elements 4 thus face an annular space 5 which is formed in the region of the blade roots 32 of the individual moving blades 3a, 3b between the rotor and a guide blade arrangement 6. As explained in the introduction, the flow arising in this annular space 5 can be undesirably swirled in a configuration of the overhangs 310 of the blade bases 31 used for the connection between the rotor blades 3a, 3b and a securing element 4 if individual overhangs 310 are offset from one another due to tolerances. Individual overhangs 31 then protrude completely into the flow path defined in a circular ring around the axis of rotation along the securing plates 4 or are set back radially outward for this purpose (cf Figures 5B and 5C ).

An improvement can be achieved here with the solution according to the invention. After this, an overhang 310, which is provided for a form-fitting connection with a radially outer edge 43 of a multipart or one-part securing element, such as a securing plate 4, is formed with an edge section of defined geometry and size that is set back in the radially outer direction ra. With the solution according to the invention, even with a nominal arrangement of the individual rotor blades 3a, 3b relative to one another, it can be ruled out that on each pair of adjacent rotor blades 3a, 3b there is a rectilinear or arc-shaped course of the radially inner lower edges of the overhangs 310 that follow one another along the circumferential direction U is. Rather, at least one defined radial recess is provided from the outset, which influences the flow as little as possible, but in any case in a foreseeable manner. A plurality of recesses distributed along the circumferential direction U are preferably provided, in particular on each pair of blade bases 31 arranged adjacent to one another.

In the variant of the Figures 1A to 1C For example, an overhang 310 of a blade base 31 of each rotor blade 3a, 3b fixed to the rotor base part 2 has two edge sections 311a and 311c set back radially outwards. These two radially recessed edge sections 311a and 311c have a smaller extension in the radially inward direction ri than a third edge section 311b formed between them. The length of the third edge section 311b along the circumferential direction U can be at least twice the shape and position tolerances of a gap between the axial securing elements 4 and/or at least half of a minimum width d of a blade neck 320 of the blade root 32 inserted into the associated fastening groove 20 Rotor blade 3a or 3b (cf. the individual representation of a rotor blade 3a of Figure 1D ). The length of the third edge section 311b along the circumferential direction U is less than 60%, optionally less than 50% or even less than 35% of the total length L of an overhang 310 along the circumferential direction U.

A recessed edge section 311a or 311c is provided at the ends of an overhang 310 that are spaced apart from one another along the circumferential direction U. The edge sections 311a and 311c extend with different lengths a1 and a2 in the circumferential direction U. Both recessed edge sections 311a and 311c also form an area of the lower edge of the overhang 310 that runs inclined to the circumferential direction U. Starting from the middle, third edge section 311b, each recessed edge section 311a, 311c runs obliquely outwards towards the respective end, so that a radial extension of the respective recessed edge section 311a or 311c towards the respective lateral edge of the overhang 310 steadily decreases.

The individual edge sections 311a and 311c are each set back up to a height b1 or b2 compared to the central edge section 311b. In the present case, this height b1 or b2 is greater than 0.8 mm and is approximately 1 mm. The extent in the circumferential direction U of the respective recessed edge section 311a, 311c is in turn measured as a—preferably integer—multiple of this height b1 or b2. In the present case, a length a1, a2 corresponds to at least three times a height b1 or b2 of the respective recessed edge section 311a, 311c.

The heights b1 and b2 of the recessed edge sections 311a and 311c are dimensioned such that in the region of mutually adjacent moving blades 3a, 3b and so that adjoining blade bases 31 are formed by two recessed edge sections 311c and 311a running obliquely towards one another in each case a radial recess 33 in the course of the lower edges of a plurality of securing plates 4 following one another in the circumferential direction U. This radial recess 33 is dimensioned via the recessed edge sections 311c and 311a of the individual rotor blades 3a and 3b such that even with a tolerance-related maximum radial offset g of two rotor blades 3a and 3b, a radial depth of the respective recess 33 is greater than the offset g and preferably corresponds to a multiple of the offset g. A (relevant) influence on the flow due to the offset g is thus excluded or minimal (cf Figure 1B ).

Naturally, the recessed edge sections 311a and 311c still provide a sufficient extension of the overhang 310 in the radially inner direction ri, so that there is also a groove 3100 in the area of a recessed edge section 311a or 311c for the surrounded radially outer edge 43 of the securing plate 4. The radially inner edge 42 of a securing plate 4 is accommodated in a groove 2100 of the rotor base part 2, which is formed by an overhang 210 projecting in the radially outer direction ra. In this way, the securing plate 4 ensures that the individual rotor blades 3a, 3b are secured axially on the rotor base part 2 in the region of their respective blade root 32, which is at least partially covered by a securing plate 4 (cf figure 3 ).

In contrast to the solution known from the prior art according to the Figures 5A to 5D (cf. in particular Figure 5D ) is also achieved via the recessed edge sections 311a and 311c that, with the edge section 311b lying in between along the circumferential direction U, the overhang 310 extends further radially inwards only in the area in which the fastening groove 20 is located. In this way, the radially inwardly projecting edge section 311b is dimensioned such that the blade root 32 can be pushed in the axial direction through the fastening groove 20 and the gap thus defined between two webs 22 of the rotor base part 2 if the securing plate 4 is not yet attached or is no longer attached is. This is with an overhang of constant radial extension according to the Figure 5D not possible. Here, the overhang 310 blocks the blade root 32 from being pushed through a fastening groove 20 . The overhang 310 cannot be pushed over the webs 22 of the rotor base part 2 lying opposite one another and bordered laterally by a fastening groove 20 . For complete axial displacement through the fastening groove 30, the radial would have to be here Extension of the blade root 32 and thus the length of a blade neck 320 are increased, so that a lower edge of the overhang 310 consistently runs radially further outwards than the end of the webs 22. But this would be accompanied by an increase in the weight of a moving blade 3a, 3b. In contrast, the additional assembly advantage can be realized in the embodiment variant of a solution according to the invention without a weight disadvantage.

At the one with the Figures 2A and 2 B Illustrated variant is the shape of the recessed edge portions 311a and 311c compared to the variant of FIG Figures 1A to 1C varies. An overhang 310 on a blade base 31 is profiled so that the two edge sections 311a and 311b of a rotor blade 3a or 3b, which are spaced apart from one another along the circumferential direction U, are in the radially outer direction ra opposite the middle, third edge section 311b of the overhang 310 of the respective rotor blade 3a or 3a 3b are designed to be set back radially. The individual recessed edge sections 311a and 311c each have areas of constant radial extension along the circumferential direction U. In other words, each of the recessed edge portions 311a, 311c of a blade Figures 2A and 2 B at least one area in which a height of the respective recessed edge section 311a, 311c does not decrease in the circumferential direction U or in the opposite direction thereto.

In particular, this means that a recess 33 defined in the area of the blade bases 31 of two adjacent moving blades 3a, 3b is visible in the view along the axis of rotation of the figure 2 is trapezoidal, while the recess 33 in the variant of Figures 1A to 1C is triangular. If the course of the lower edges of the recessed edge sections 311a, 311c is more rounded, an elliptical recess can also be formed in a possible development.

A machining manufacturing process or thermal material removal can be provided for the production of the reduced edge sections 311a, 311c on a rotor blade 3a or 3b. For example, the withdrawn edge portions 311a and 311c in the embodiment of Figures 1A to 1C can be made comparatively easily by grinding. A profiled version corresponding to the variant of Figures 2A and 2 B can be produced, for example, by eroding. The recessed edge sections 311a and 311c can be produced in one operation with (not shown here) Damper pockets or other functional areas are made on the blades 3a, 3b, which are usually also made by eroding.

Based on Figure 2B is in accordance with the Figure 1C still partially hiding the securing plate 4, that also in this embodiment variant, the recessed edge sections 311a and 311c of the overhang 310 do not block the blade root 32 from being pushed through a fastening groove 20 in the axial direction. The radially inwardly projecting (middle) edge portion 311b is dimensioned such that it fits through the gap defined between two ridges 22 of the rotor base part 2 at the upper end of the fastening groove 20 .

Based on the partial representation of a longitudinal section according to the figure 4 the design of the locking plate 4 is illustrated separately. The locking plate 4 has a central region 40 lying between the radially inner and radially outer edges 42 and 43 . From the figure 4 shows in particular how a radially outer edge 43 of the locking plate 4 is received in the groove 3100 of the blade base 31 of a moving blade 3b and encompassed by the radially inwardly extending overhang 310, while the central region 40 extends outside of the groove 3100 along the blade root 32 extends.

Reference List

T

gas turbine engine

11

low-pressure compressor

12

high-pressure compressor

13

high pressure turbine

14

medium pressure turbine

15

low pressure turbine

2

rotor base part

20

mounting groove

210

Got over

2100

groove

22

web

30

shovel blade

31

blade base

310

overhang

3100

groove

311

edge

311a, 311b, 311c

edge section

32

blade root

320

shovel neck

33

Radial Return

3a, 3b

blade

4

fuse plate (fuse element)

40

midrange

42

inner rim

43

Outer Rim

5

annular gap

6

guide vane arrangement

A

outlet

a1, a2

length

B

bypass channel

BK

combustion chamber section

b1, b2

Height

c

Broad

i.e

Minimum width of the bucket neck

E

Inlet / Intake

f

fan

G

offset

L

overall length

M

Central axis / axis of rotation

R

entry direction

ra, ri

radial direction

TT

turbine

u

circumferential direction

V

compressor

Claims (13)

1. Rotor for an engine (T), comprising

   - a rotor base part (2) which has fastening grooves (20) for rotor blades (3a, 3b), said fastening grooves being arranged in succession along a circumferential direction (U) about an axis of rotation (M),

   - a plurality of rotor blades (3a, 3b) which are each held in an associated fastening groove (20) in a positively locking manner by way of a blade root (32), and

   - at least one securing element (4) for axially securing, in relation to the axis of rotation (M), at least one of the rotor blades (3a, 3b) to the rotor base part (2),

   wherein the at least one securing element (4) has two peripheries (42, 43) which are spaced apart radially from one another and by way of which the securing element (4) is held, on the one hand, on the rotor base part (2) and, on the other hand, on the at least one rotor blade (3a, 3b) in a positively locking manner, and for the positively locking engagement with the rotor blade (3a, 3b), the one periphery (43) of the securing element (4) is encompassed at least in one region by an overhang (310) of the rotor blade (3a, 3b), said overhang for this purpose extending, with respect to the axis of rotation (M), radially inwardly over the one periphery (43) of the securing element (4) and along the circumferential direction (U),

   wherein a respective gap between two webs (22) of the rotor base part (2) is defined by a fastening groove (20), and

   wherein the overhang (310) has, along its extent in the circumferential direction (U), at least one peripheral portion (311a, 311c) which engages around the periphery (43) of the securing element (4) and which is set back, at a radially inner lower edge of the overhang (310), in a radially outwardly pointing direction (ra) in relation to at least one further peripheral portion (311b) of the overhang (310), said further peripheral portion likewise engaging around the periphery (43) of the securing element (4),

   characterized in that

   the overhang (310) has two, first and second, peripheral portions (311a, 311c) which are each provided at an end of the overhang (310) in relation to the circumferential direction (U) and are each set back in the radially outwardly pointing direction (ra) in relation to at least one further third peripheral portion (311b) of the overhang (310), said further peripheral portion likewise engaging around the periphery (43) of the securing element (4), in such a way that the blade root (32) and a lower edge of the overhang (310) can be pushed through the gaps in the rotor base part (2) when the securing element (4) is not yet attached or is no longer attached.
2. Rotor according to Claim 1, characterized in that at least one of the first and second radially outwardly set-back peripheral portions (311a, 311c) has a smaller extent in the radially inwardly pointing direction (ri).
3. Rotor according to Claim 1 or 2, characterized in that at least one of the first and second radially outwardly set-back peripheral portions (311a, 311c) forms, at the radially inner lower edge, a region that runs in an at least partially inclined manner with respect to the circumferential direction (U).
4. Rotor according to one of the preceding claims, characterized in that at least one of the first and second radially outwardly set-back peripheral portions (311a, 311c) extends, along the circumferential direction (U), with a length (a1, a2) that corresponds to at least three times a height (b1, b2) by which the radially outwardly set-back peripheral portion (311a, 311c) is maximally set back in relation to the adjoining third peripheral portion (311b) of the overhang (310).
5. Rotor according to one of the preceding claims, characterized in that at least one of the first and second radially outwardly set-back peripheral portions (311a, 311c) is set back in relation to the adjoining third peripheral portion (311b) of the overhang (310) at least by a height (b1, b2) of 0.5 mm, in particular at least by a height (b1, b2) of 0.8 mm or 1 mm.
6. Rotor according to one of the preceding claims, characterized in that the two set-back peripheral portions (311a, 311c) are set back to differing extents and/or extend along the circumferential direction (U) with differing lengths (a1, a2).
7. Rotor according to one of the preceding claims, characterized in that the first and second radially outwardly set-back peripheral portions (311a, 311c) are provided at ends of the overhang (310) which are spaced apart from one another along the circumferential direction (U).
8. Rotor according to one of the preceding claims, characterized in that one of the first and second radially outwardly set-back peripheral portions (311a, 311c) are set back in relation to the adjoining third peripheral portion (311b) of the overhang (310) at least by the sum of predefined dimensional and positional tolerances of this third peripheral portion (311b), wherein the dimensional and positional tolerances predefine a nominal position of the third peripheral portion (311b) with respect to the associated fastening groove (20) and/or with respect to an overhang (310) of an adjacent rotor blade (3b, 3a).
9. Rotor according to one of the preceding claims, characterized in that overhangs with mutually adjoining and in each case radially outwardly set-back peripheral portions (311a, 311c) are provided on at least two rotor blades (3a, 3b) of the rotor which are arranged adjacent to one another along the circumferential direction (U), such that a radially outwardly directed recess (33) of defined minimum length and minimum height is formed in the region of the mutually adjoining peripheral portions (311a, 311c) of the two adjacent rotor blades (3a, 3b).
10. Rotor according to Claim 9, characterized in that the recess (33) is elliptical, trapezoidal or triangular in a view along the axis of rotation (M).
11. Rotor according to Claim 9 or 10, characterized in that overhangs with mutually adjoining and in each case radially outwardly set-back peripheral portions (311a, 311c) are provided along the circumferential direction (U) at each pair of mutually adjacently arranged rotor blades (3a, 3b), such that a respective radially outwardly directed recess (33) of defined minimum length and minimum height is formed along the circumferential direction (U) in the region of mutually adjoining peripheral portions (311a, 311c) of two adjacent rotor blades (3a, 3b).
12. Rotor according to one of the preceding claims, characterized in that the at least one radially outwardly set-back peripheral portion (311a, 311c) is produced by mechanical or thermal abrasion of material.
13. Rotor according to one of the preceding claims, characterized in that the at least one securing element (4) is provided for axially securing at least two rotor blades (3a, 3b), and the one periphery (43) of the securing element (4) is thus encompassed by overhangs (310) of at least two rotor blades (3a, 3b).

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