Rotor with overhang on rotor blades for a securing element

Abstract

The present invention relates to a rotor for a drive unit (T), comprising: - a rotor base part (2) having mounting grooves (20) arranged one behind the other along a circumferential direction (U) about an axis of rotation (M) for rotor blades (3a, 3b), - several rotor blades (3a, 3b) each held in a positive-locking manner in an associated mounting groove (20) via a blade root (32), and - at least one locking element (4) for axially securing at least one of the rotor blades (3a, 3b) to the rotor base part (2) with respect to the axis of rotation (M), wherein the at least one locking element (4) has two radially spaced edges (42, 43) by means of which the locking element (4) is positively locked on the rotor base part (2) on one side and on the other side to the at least one rotor blade (3a, 3b) and is responsible for the positive locking with the rotor blade (3a, 3b).3b) one edge (43) of the locking element (4) is encompassed at least in a region by an overhang (310) of the guide vane (3a, 3b), which for this purpose extends radially inwards with respect to the axis of rotation (M) over one edge (43) of the locking element (4) and along the circumferential direction (U). According to the invention, the overhang (310) has at least one edge section (311a, 311c) encompassing the edge (43) of the locking element (4) along its circumferential extension (U), which is reduced in a radially outward direction (ra) at a radially inner lower edge of the overhang (310) compared to at least one further edge section (311b) of the overhang (310) that also encompasses the edge (43) of the locking element (4).

Description

[0001] The invention relates to a rotor for an engine, in particular a gas turbine engine according to the preamble of claim 1.

[0002] EP 2 873 807 A1 and EP 2 860 350 A1 disclose known rotors according to the preamble of claim 1. A rotor of this type, known, for example, from US 5,256,035, has a rotor base part that has mounting points for rotor blades arranged one behind the other along a circumferential direction about an axis of rotation. The individual rotor blades are each positively locked in a corresponding mounting groove by means of a blade root. For axial locking with respect to the axis of rotation, a one-piece or multi-piece locking element is provided, which is positively locked to at least one of the rotor blades at a radially outer edge and positively locked to the rotor base part at a radially inner edge.

[0003] US Patent 5,256,035, for example, describes a multi-part locking element consisting of several plate segments and a retaining ring. A radially inner edge of each plate segment is positively engaged in a groove of the rotor base, such that a radially outward-extending overhang of the rotor base engages the radially inner edge of each plate segment. The retaining ring is, in turn, received in a groove formed at the base of a rotor blade. A radially inward-extending overhang of the blade base engages the radially outer edge of the retaining ring, thereby securing a plate segment located adjacent to and axially beside the retaining ring.

[0004] However, considering the individual overhangs of the multiple rotor blades connected to the rotor base, undesirable turbulence can occur during rotor operation in the area of ​​two adjacent overhangs, particularly in a high-speed, highly loaded rotor such as those used in a gas turbine engine, for example in the high-pressure compressor or the high-pressure turbine. This can be seen from the Figures 5A , 5B , 5C and 5D illustrated in more detail, showing a section of a rotor known from the prior art.

[0005] The rotor comprises a rotor base part in the form of a rotor disk 2 with several mounting grooves 20 spaced apart from each other along a circumferential direction U. A blade root 32 of a rotor blade 3a, 3b is received in each mounting groove 20. Of the multiple rotor blades arranged one behind the other along the circumference of the rotor (for example, 20 pieces), the following are located in the Figures 5A , 5B , 5C and 5D Only two sections are shown, viewed along the rotational axis of the rotor. Each rotor blade 3a, 3b comprises a blade base 31, from which a blade 30 projects radially. The blade root 32 extends from the blade base 31 in a radially inward direction ri.

[0006] The blade base 31 of a rotor blade 3a or 3b each forms a radially inwardly extending overhang 310, i.e., extending along the radial direction ri pointing towards it. A radially outer edge 43 of a retaining plate 4 is encompassed by this overhang 310. Several (at least two) rotor blades 3a and 3b are axially secured to the rotor base part 2 in the area of ​​the mounting grooves 20 by this retaining plate 4. For this purpose, the retaining plate 4 is connected not only to the rotor blades 3a and 3b, but also to the rotor base part 2. A positive locking mechanism between the rotor base part 2 and the retaining plate 4 engages within the Figures 5A to 5CThe not shown projection of the rotor base part 2 forms a radially inner edge 42 of the locking plate 4. The longitudinally extended locking plate 4, which extends circumferentially, is thus held both at its radially outer edge 43 and at its radially inner edge 42 and is received in a groove formed by a rotor blade 3a, 3b or the rotor base part 2.

[0007] As particularly evident from the Figure 5AAs can be seen, a rotor blade 3a, 3b known from the prior art each forms an overhang 310 to encompass the radially outer edge 43 of the retaining plate 4, which forms a continuous straight or arc-shaped edge 311 over a total length L along the circumferential direction U. Along the circumferential direction U, the respective overhangs 310 of adjacent edges 311 of a pair of rotor blades 3a and 3b should thus be aligned with each other, 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.

[0008] However, this is often not the case in practice, as the Figures 5B and 5C To illustrate this, due to permissible tolerances, the individual overhangs 310 of adjacent running blades 3a, 3b may be radially offset from each other. Figures 5B and5C Here, an offset g of the two guide vanes 3a and 3b in the area of ​​their overhangs 310 is shown as an example. In the variant of Figure 5B The one (left) rotor blade 3b is offset radially inwards relative to the adjacent (right) rotor blade 3a. With respect to a rotational axis of the rotor around the rotational axis M along the circumferential direction, the overhang 310 of the one rotor blade 3b thus projects into an annular gap flow in the circumferential direction U (offset "into 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 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.

[0009] In practice, the offset g observed for both cases is only in the range of 0.2 mm to 0.4 mm for a rotor. However, especially with high-speed rotors for a gas turbine engine, for example in the rotor of a high-pressure turbine or a high-pressure compressor, this can lead to undesirable turbulence in the area of ​​adjacent blade bases 31 and thus adjacent overhangs 310.

[0010] The invention is based on the objective of improving a rotor in this respect.

[0011] This problem is solved with a rotor of claim 1.

[0012] According to the invention, a rotor with a specially designed overhang on at least one rotor blade is proposed, positively connected to the rotor base part. The overhang has two, first and second, edge sections along its circumferential extent, each of which is provided at one end of the overhang relative to the circumferential direction and is set back in a radially outward direction relative to at least one further third edge section of the overhang, which also encompasses the edge of the locking element, such that the blade root and a lower edge of the overhang can be pushed through the gap in the rotor base part when the locking element is not yet or no longer attached.At least two rotor blades arranged adjacent to each other along the circumferential direction feature overhangs with adjacent, radially outwardly recessed edge sections. This creates a radially outward-facing recess of defined minimum length and height in the area of ​​the adjacent edge sections of two neighboring rotor blades. This radial recess thus intentionally interrupts the circular path of the successive edges of the individual overhangs along the circumferential direction.

[0013] Consequently, the overhang of at least one rotor blade in a rotor according to the invention is reduced or set back at a lower edge of the overhang in a radially outward direction such that the overhang does not have a straight or arc-shaped profile along the circumferential direction at a radially inner lower edge. 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 extent decreases continuously in the circumferential direction and thus defines a region of the lower edge of the overhang that runs obliquely to the circumferential direction. Thus, for example, radially offset and / or angled regions are formed at a radially inner lower edge of an overhang.A recess is thus defined from the outset, preferably in the area of ​​adjacent overhangs. This can, particularly with appropriate dimensioning, minimize or eliminate disruptive turbulence in the area of ​​the locking element. Furthermore, this allows for weight reduction and simplification of the assembly and / or disassembly of a rotor blade. The latter is achieved by designing and arranging the at least one recessed edge section along the circumferential direction in such a way that at least part of the overhang can be pushed axially through the mounting groove when the locking element is not yet, or no longer, fixed to the rotor base.

[0014] At least one of the first and second radially outwardly recessed edge sections can have a smaller radially inward extension than an adjacent edge section. The overhang thus extends less radially inward in the area of ​​the recessed edge section. In one embodiment, at least one of the first and second radially outwardly recessed edge sections is provided at a circumferential end of the overhang. In this way, a defined recess is provided via the recessed edge section in the area where the bases of two adjacent rotor blades meet.

[0015] In one embodiment, at least one of the first and second radially outwardly recessed edge sections forms a region at the radially inner lower edge of the overhang that is at least partially inclined in the circumferential direction. Thus, the recessed edge section can not only be designed to recede in steps to an adjacent edge section of the overhang, but can also form a recess that continuously increases or decreases, at least in sections, in the circumferential direction.

[0016] It has been shown that for certain applications and especially rotor speeds, a specific minimum size for the radially outward projection of the edge section of a rotor blade overhang is advantageous in order to reduce turbulence. In this context, one embodiment provides that the at least one radially outward projection extends along the circumferential direction of the rotor with a length that is at least three times, and in one variant at least four times, the height by which the radially outward projection is projected relative to an adjacent edge section of the overhang. With a minimum height b by which the at least one edge section projects radially outward relative to an adjacent edge section of the overhang, i.e.,, is radially recessed in an outward-pointing direction, and has a length a with which the at least one recessed edge section extends along the circumferential direction, this consequently means that: a ≥ 3b.

[0017] Alternatively or additionally, at least one radially outwardly recessed edge section is set back by a height of at least 0.5 mm, and in particular by a height of at least 0.8 mm or 1 mm, relative to an adjacent edge section of the rotor blade overhang. A recess is thus formed over the recessed edge section, which, with the nominal alignment of two adjacent rotor blades, has a maximum depth of at least 0.5 mm, 0.8 mm, or 1 mm.

[0018] In one variant, the overhang of a rotor blade can have two edge sections, namely a first and a second edge section, each of which is set back in a radially outward direction relative to at least one further third edge section of the overhang that also encompasses the edge of the securing element. The first and second edge sections are thus spatially separated and spaced apart along the circumferential direction, but each is set back radially outward relative to at least one third edge section of the blade overhang.

[0019] The two recessed edge sections can be recessed to different degrees and / or extend along the circumference with different lengths relative to each other. The overhang of a rotor blade can thus be asymmetrical with respect to a radial direction. This allows, for example, a rotation-direction-optimized design of a recess formed by two adjacent edge sections of two neighboring rotor blades, each recessed radially outwards.

[0020] Particularly with regard to such a variant, it can be provided that the first and second radially outwardly recessed edge sections of a rotor blade are located at the ends of the associated overhang (and a blade base of the associated rotor blade) that are spaced apart along the circumference. Thus, along the circumference of the rotor, a second edge section of one (first) rotor blade overhang and a first edge section of another (second) rotor blade overhang abut each other when adjacent rotor blades and their respective blade bases are connected.

[0021] In one variant, at least one of the first and second radially outwardly recessed edge sections is set back relative to the adjacent third edge section of the rotor blade overhang by at least the sum of the form and position tolerances of this third edge section. A recessed first or second edge section thus forms a step which, with two adjacent rotor blades in nominal alignment, has a maximum (radial) depth of at least the sum of the form and position tolerances of the third edge section. The form and position tolerances define a nominal position of the third edge section with respect to the associated mounting groove and / or with respect to an overhang of an adjacent rotor blade.

[0022] A setback defined in the area of ​​the blade bases of two adjacent running blades is, for example, elliptical, trapezoidal or triangular in a view along the axis of rotation.

[0023] Along the circumference of the rotor, overhangs with adjacent and radially outwardly recessed edge sections can be provided on each pair of adjacent rotor blades, so that a radially outwardly directed recess of defined minimum length and minimum height is formed along the circumference in the area of ​​adjacent edge sections of two neighboring rotor blades. In this variant, the formation of a recess is therefore not limited to individual rotor blade pairs, but is provided continuously in every area of ​​two adjacent rotor blades.

[0024] At least one of the first and second radially outward recessed edge sections can be produced, for example, by mechanical material removal. This includes manufacturing by a subtractive process such as grinding or milling. In such a variant, material can therefore be selectively removed, for example, ground off, from the overhang of a blade base to ensure that the radially inward lower edge of the overhang no longer has a straight profile.

[0025] Alternatively, a radially recessed edge section can be produced by thermal material removal. For example, this can be achieved by electrical discharge machining (EDM). This includes spark EDM, which allows for the relatively simple production of a recessed edge section, even on a subsequent overhang made of high-strength material. The (thermal) material removal from the overhang to create the recessed edge section can be performed in a single operation along with the production of specific functional areas on a rotor blade. For instance, it is common practice to produce a functional area, such as a damper pocket or a blade base area with at least one cutout for weight reduction, on a rotor blade by EDM in the blade base region.In such a work step, the overhang of a running blade can also be machined accordingly in order to provide a radially outwardly recessed edge section.

[0026] In principle, at least one locking element can be provided for the axial securing of at least two rotor blades. In this case, a locking element, preferably plate-shaped, is encompassed at one (radially outer) edge by the overhangs of at least two rotor blades.

[0027] The accompanying figures illustrate possible embodiments of the invention.

[0028] They show: Figure 1A shows a partial view of a rotor designed according to the invention, looking along an axis of rotation of the rotor at two radially outwardly recessed overhangs of two adjacent rotor blades; Figure 1B shows the Figure 1AAccording to a consensus, there is a radial offset between two blade bases of adjacent rotor blades compared to the one in the Figure 1A The nominal orientation of the two blades relative to each other is shown; Figure 1Cin with the Figure 1A In agreement, the rotor is shown with a locking element partially obscured to illustrate a blade neck of a rotor blade inserted into a mounting groove; Figure 1: Rotor blade in detail; Figure 2: Rotor blade with the Figures 1A and 1B According to a consensus, another design variant features geometrically different recessed edge sections on two overhangs of two running blades; Figure 2Bin with the Figure 1C unanimous opinion the rotor of the Figure 2AFigure 3 shows 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 shows a partial sectional view of the rotor obtained along a section line parallel to the axis of rotation of the rotor; Figures 5A - 5D each show a partial view of a rotor known from the prior art with two adjacent rotor blades, the overhangs of which have a straight edge and thus nominally aligned lower edges ( Figure 5A ) and, if applicable, lower edges offset from each other due to tolerances ( Figures 5B and 5C ) as well as partially hiding a safety element ( 5D Figure ) are shown; Figure 6 in sectional view schematically shows a gas turbine engine in which a rotor according to the invention is used.

[0029] The Figure 6Figure 1 schematically illustrates a (gas turbine) engine T in which the individual engine components are arranged one behind the other along a central or rotational axis M. Air is drawn in at an inlet E of the engine T along an entry direction E by means of a fan F. This fan F is driven by a shaft that is set in rotation by a turbine TT. The turbine TT is connected to a compressor V, which, for example, has a low-pressure compressor 11 and a high-pressure compressor 12, and optionally also an intermediate-pressure compressor. The fan F supplies air to the compressor V on one side and to a bypass channel B for generating thrust on the other. The air delivered by the compressor V finally enters a combustion chamber section BK, where the drive energy for the turbine TT is generated.The turbine TT comprises a high-pressure turbine 13, a medium-pressure turbine 14, and a low-pressure turbine 15. The energy released during combustion in the turbine TT drives the fan F, which then generates the required thrust via the air conveyed into the bypass channel B. The air exits the bypass channel B at an outlet A at the end of the engine T, where the exhaust gases from the turbine TT flow outwards. The outlet A typically features a thrust nozzle.

[0030] Particularly in the area of ​​high-pressure turbine 13, at least one rotor comes into contact with the introductory section. Figures 5A to 5DThe illustrated configuration is used for application. Here, the rotor is arranged and rotatably mounted about the central axis or axis of rotation M such that the individual locking 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 locking elements 4 thus face an annular space 5, which is formed in the region of the blade roots 32 of the individual rotor blades 3a, 3b between the rotor and a guide vane assembly 6. As explained in the introduction, the flow generated in this annular space 5 can become undesirably turbulent if the overhangs 310 of the blade bases 31, used for the connection between the rotor blades 3a, 3b and a locking element 4, are misaligned due to tolerances.Then individual overhangs 31 project completely into the annular flow path defined around the axis of rotation along the retaining plates 4 or are set back radially outwards for this purpose (compare . Figures 5B and 5C ).

[0031] The solution according to the invention offers an improvement in this respect. According to this invention, an overhang 310, which is provided for a positive-locking connection with a radially outer edge 43 of a multi-part or one-piece locking element, such as a locking plate 4, is designed with a radially outward recessed edge section of defined geometry and size. With the solution according to the invention, even with the nominal arrangement of the individual impeller blades 3a, 3b relative to each other, it can be prevented that the radially inner lower edges of the overhangs 310, which are successive along the circumferential direction U, have a straight or arc-shaped course on each pair of adjacent impeller blades 3a, 3b. Instead, at least one defined radial recess is provided from the outset, which influences the flow as little as possible, but in any case predictably.Preferably several recesses distributed along the circumferential direction U are provided, in particular at each pair of mutually adjacent blade bases 31.

[0032] In the version of the Figures 1A to 1CFor example, an overhang 310 of a blade base 31 of each rotor blade 3a, 3b fixed to the rotor base part 2 has two radially outwardly recessed edge sections 311a and 311c. These two radially recessed edge sections 311a and 311c have a shorter 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 form and position tolerances of a gap between the axial locking elements 4 and / or at least half of a minimum width d of a blade neck 320 of the blade root 32 of a rotor blade 3a or 3b inserted into the associated mounting groove 20 (see the detailed illustration of a rotor blade 3a of the Figure 1D). The length of the third edge section 311b along the circumferential direction U is less than 60%, possibly less than 50% or even less than 35% of the total length L of an overhang 310 along the circumferential direction U.

[0033] At the ends of an overhang 310, spaced apart from each other along the circumferential direction U, a recessed edge section 311a or 311c is provided. The edge sections 311a and 311c extend along the circumferential direction U with different lengths a1 and a2. Both recessed edge sections 311a and 311c also form a region of the lower edge of the overhang 310 that slopes towards the circumferential direction U. Each recessed edge section 311a, 311c extends obliquely outwards from the central, third edge section 311b towards its respective end, such that the radial extent of each recessed edge section 311a or 311c decreases continuously towards the respective lateral edge of the overhang 310.

[0034] Here, the individual edge sections 311a and 311c are each set back from the central edge section 311b to a height b1 or b2. This height b1 or b2 is greater than 0.8 mm and is approximately 1 mm. The circumferential extent U of the respective set-back edge section 311a, 311c is measured as a multiple – preferably an integer – of this height b1 or b2. In this case, a length a1, a2 corresponds to at least three times the height b1 or b2 of the respective set-back edge section 311a, 311c.

[0035] The heights b1 and b2 of the recessed edge sections 311a and 311c are dimensioned such that, in the area of ​​adjacent guide vanes 3a, 3b and thus adjacent vane bases 31, a radial recess 33 is formed by two obliquely converging recessed edge sections 311c and 311a along the circumferentially U-directed lower edges of several retaining plates 4. This radial recess 33 is dimensioned via the recessed edge sections 311c and 311a of the individual guide vanes 3a and 3b such that, even with a tolerance-related maximum radial offset g between two guide vanes 3a and 3b, the radial depth of the respective recess 33 is greater than the offset g and preferably corresponds to a multiple of the offset g. This means that any (relevant) influence on the flow due to the offset g is either excluded or minimal (compare Figure 1B ).

[0036] The recessed edge sections 311a and 311c naturally still provide sufficient extension of the overhang 310 in the radially inner direction ri, so that even in the area of ​​a recessed edge section 311a or 311c, a groove 3100 is present for the encompassed radially outer edge 43 of the locking plate 4. The radially inner edge 42 of a locking plate 4 is received in a groove 2100 of the rotor base part 2, which is formed by a projection 210 extending in the radially outer direction ra. In this way, the locking plate 4 ensures that the individual rotor blades 3a, 3b are axially secured to the rotor base part 2 in the area of ​​their respective blade root 32, which a locking plate 4 at least partially covers (see also Figure 3 ).

[0037] In contrast to the solution known from the prior art according to the Figures 5A to 5D (see in particular) 5D FigureThe recessed edge sections 311a and 311c further ensure that the overhang 310 extends radially inwards only in the area where the mounting groove 20 is located, with the intermediate edge section 311b lying along the circumferential direction U. The radially inwardly projecting edge section 311b is thus dimensioned so that the blade root 32 can be pushed axially through the mounting groove 20 and the gap defined therein between two webs 22 of the rotor base part 2, even if the locking plate 4 is not yet or no longer attached. This is achieved with an overhang of constant radial extent according to the 5D FigureThis is not possible. Here, the overhang 310 blocks the blade root from passing through a fastening groove 20. The overhang 310 cannot be pushed over the opposing webs 22 of the rotor base part 2, which are laterally bounded by a fastening groove 20. For complete axial movement through the fastening groove 30, the radial extent of the blade root 32, and thus the length of a blade neck 320, would have to be increased so that a lower edge of the overhang 310 extends radially further outwards than the ends of the webs 22. However, this would result in an increase in the weight of a rotor blade 3a, 3b. In contrast, the additional assembly advantage of the illustrated embodiment of a solution according to the invention can be realized without any weight disadvantage.

[0038] In the with the Figures 2A and 2BThe illustrated variant is the shape of the withdrawn border sections 311a and 311c compared to the variant of Figures 1A to 1C The overhang 310 at a blade base 31 is profiled such that the two edge sections 311a and 311b of a rotor blade 3a or 3b, spaced apart from each other along the circumferential direction U, are radially recessed in the outer direction ra relative to the middle, third edge section 311b of the overhang 310 of the respective rotor blade 3a or 3b. The individual recessed edge sections 311a and 311c each have areas of constant radial extent along the circumferential direction U. In other words, each of the recessed edge sections 311a, 311c of a rotor blade has Figures 2A and 2B at least one area where the height of the respective recessed edge section 311a, 311c does not decrease in the circumferential direction U or in the opposite direction.

[0039] In particular, this ensures that a setback 33 defined in the area of ​​the blade bases 31 of two adjacent running blades 3a, 3b is visible in the view along the axis of rotation of the Figure 2 is trapezoidal, while the return step 33 in the variant of the Figures 1A to 1C It is triangular in shape. With a more rounded shape of the lower edges of the recessed edge sections 311a, 311c, an elliptical recess may also be formed in a possible further development.

[0040] For the production of the recessed edge sections 311a, 311c on a rotor blade 3a or 3b, a machining process or thermal material removal can be used. For example, the recessed edge sections 311a and 311c in the embodiment of Figures 1A to 1C They can be produced relatively easily by grinding. A profiled version corresponding to the variant of Figures 2A and 2BThis can be produced, for example, by electrical discharge machining (EDM). The production of the recessed edge sections 311a and 311c can be carried out in a single operation together with (not shown here) damper pockets or other functional areas on the rotor blades 3a, 3b, which are also usually produced by EDM.

[0041] Based on the Figure 2B is in accordance with the Figure 1C Even with the locking plate 4 partially obscured, it is illustrated that in this embodiment, the recessed edge sections 311a and 311c ensure that the overhang 310 does not block the axial insertion of the blade root 32 through a fastening groove 20. The radially inwardly projecting (middle) edge section 311b is dimensioned such that it fits through the gap defined between two webs 22 of the rotor base part 2 at the upper end of the fastening groove 20.

[0042] 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 area 40 located between the radially inner and radially outer edges 42 and 43. From the Figure 4 It is particularly evident how a radially outer edge 43 of the locking plate 4 is received in the groove 3100 of the blade base 31 of a running blade 3b and is encompassed by the radially inwardly extending overhang 310, while the central area 40 extends outside the groove 3100 along the blade root 32. Reference symbol list

[0043] 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 section 20 Mounting groove 210 Overhang 2100 Groove 22 Web 30 Blade 31 Blade base 310 Overhang 3100 Groove 311 Edge 311a, 311b, 311c Edge section 32 Blade root 320 Blade neck 33 Radial recess 3a, 3b Rotor blade 4 Locking plate (locking element) 40 Center section 42 Inner edge 43 Outer edge 5 Annular gap 6 Guide vane arrangement A Outlet a1, a2 Length B Bypass channel BK Combustion chamber section b1, b2 Height c Width d Minimum width of blade neck E Inlet / Intake FFan gOffset LTotal length MCentral axis / Rotation axis REInlet direction ra, riRadial direction TTTurbine UCircular direction VCompressor

Claims

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, and 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).

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 the recess (33) is elliptical, trapezoidal or triangular in a view along the axis of rotation (M).

10. 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 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).

11. 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.

12. 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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