Axially split inner ring segment for a variable guide vane nozzle of an aircraft engine, axially split inner ring, variable guide vane nozzle for an aircraft engine, and aircraft engine

Abstract

The invention relates to an axially split inner ring segment (11) for an adjustable guide vane assembly (2a, 4a) of an aircraft engine (1), an axially split inner ring (10), an adjustable guide vane assembly (2a, 4a) for an aircraft engine (1), and an aircraft engine. The inner ring (10) and the guide vane assembly (2a, 4a) improve the efficiency of the aircraft engine (1) by means of differently designed guide vane receptacles (15, 15') in the inner ring (10).

Description

[0001] The invention relates to an axially split inner ring for an adjustable guide vane ring of an aircraft engine, comprising a plurality of axially split inner ring segments arranged in a circumferential direction, wherein a row of guide vane receptacles is formed in at least one of the inner ring segments. Furthermore, the invention relates to a guide vane ring for an aircraft engine, comprising a group of adjustable guide vanes and an axially split inner ring accommodating the adjustable guide vanes. The inner ring is formed from a plurality of inner ring segments, and at least one, in particular each, of the plurality of inner ring segments has a row of guide vane receptacles for accommodating at least a portion of the group of guide vanes.The inner ring receives the guide vanes at their blade roots, which have at least one outer plate and one blade pin and, in some embodiments, an inner plate.

[0002] The components of an aircraft engine are arranged around or on an engine shaft. To describe the geometries found in aircraft engines, three main axes are defined. The first main axis runs in the direction of the engine's axis of rotation and is also referred to as the longitudinal axis, which runs in the axial direction. The first main axis defines a front and a rear of the respective geometry under consideration, with the flow gas inlet at the front and the outlet at the rear. The second axis runs in a direction perpendicular to the engine's axis of rotation and is also referred to as the radial axis, which runs in the radial direction. The second main axis defines an outside and an inside of the engine, with the engine axis being the inside and the radial direction running outwards from the engine axis.The third principal axis runs circumferentially perpendicular to the other two principal axes. The three principal axes together define three principal planes: meridian planes, which can also be referred to as meridional sections and are spanned by the longitudinal axis and a radial axis; circumferential planes, which lie on a cylindrical surface around the engine's rotational axis; and cross-sectional planes of the engine, which are arranged perpendicular to the engine's rotational axis.

[0003] The inner ring and the adjustable guide vane ring are typically arranged in a core flow channel of the aircraft engine. The core flow channel is defined by an outer casing and an inner casing, with the inner ring, together with the outer vane plates of the guide vanes, forming part of the inner casing. A common function of both the inner ring for the adjustable guide vane ring and the adjustable guide vane ring is to form an inner air seal. The inner ring is held in place by the guide vanes of the guide vane ring and is also formed with a sealing ring. Sealing linings are located on the sealing ring, which interact with corresponding sealing fins on the rotor to form a labyrinth seal to seal a radial gap between the rotor and stator.

[0004] The connection between the inner ring and the blade roots is subject to leakage. To minimize this leakage, two basic designs are known from the state of the art for internal air seals on adjustable guide vanes of a core flow channel.

[0005] The first principle concerns floating, i.e., clearance-affected, inner air seals. The inner ring can consist of two half-ring segments extending 180° in the circumferential direction, which are guided spoke-centered on the sliding surfaces of the inner vane journals of the adjustable guide vanes. The inner ring has guide vane receptacles designed with clearance in the radial direction, so that the adjustable guide vanes arranged in the guide vane receptacles can move at least in the radial direction. In the axial and circumferential directions, the connection is designed with minimal clearance or a precise fit to keep leakage as low as possible. The half-ring segments can be divided into front and rear sections in the axial direction and are usually screwed together or connected by pins. An example of this embodiment is known from EP 2 093 380 A1.The half-ring segments can also be designed as a single piece and mounted to the guide vanes from the inside via elastic deformation. With this design principle, the inner ring can freely expand and move radially, and is radially controlled by its own thermal environment in the rotor cavity.

[0006] The internal air seals with clearance have good guidance of the inner ring due to the almost clearance-free kinematics, but tend to thermally distort ("cording"), which in turn leads to a larger radial gap of the internal air seals and to compression and / or wedging of the end faces of the inner ring segments.

[0007] The second principle concerns so-called vane-tied inner air seals. The guide vanes are guided not only axially and circumferentially, but also radially. In the context of this description, "guiding" or "guiding" means that the connection is designed with minimal play or a precise fit. Typically, inner ring segments with a circumferential extension of well under 180° are selected. The inner ring segments are axially undivided and have a gap-free connection with the sliding surfaces of the inner vane journals of the guide vanes in the radial direction. This connection is usually achieved by means of a connection via pins in a groove of the rotating journal. With this design principle, the guide vanes cannot move freely radially in the inner ring seats.The inner ring segments are moved radially from the outer casing of the core flow channel via the guide vanes, to whose inner journal they are locked. Radial control is achieved via the thermal ambient conditions of the outer casing combined with the longitudinal expansion of the vanes.

[0008] A disadvantage of the known one-piece vane-tied inner air seals is that the segment size is limited by the radial mounting required from the inside to the journals. Due to the circumferentially angled vanes, this mounting also requires a sufficiently large gap between the vane plates and the bores in the inner ring segments, which leads to increased leakage at the plates, which in turn causes aerodynamic loss. The locking via the pins on the rotating vane journals cannot be supported by bushings. The resulting line contact is subject to wear, which directly affects the sealing gap.

[0009] In contrast, the object of the invention is to provide an inner ring and an adjustable guide vane ring with an inner ring for an aircraft engine, which improve the efficiency of the aircraft engine compared to the aforementioned embodiments from the prior art.

[0010] This object is achieved by an inner ring segment having the features of claim 1, an inner ring according to claim 5 and an adjustable guide vane ring having the features of claim 8.

[0011] An axially split inner ring segment according to the invention for a guide vane ring of an aircraft engine - wherein the guide vane ring has a group of adjustable guide vanes, and wherein the guide vanes each have a blade root - comprises a series of guide vane receptacles for receiving the blade roots of the group of adjustable guide vanes. This object is achieved in that the series of guide vane receptacles comprises at least one clearance receptacle and at least one guide receptacle that is different from the at least one clearance receptacle, and in that the at least one guide receptacle is designed differently from the at least one clearance receptacle with regard to a geometry for receiving the blade roots.

[0012] An axially split inner ring according to the invention for a guide vane ring of an aircraft engine - wherein the guide vane ring has a group of adjustable guide vanes, and wherein the guide vanes each have a blade root - comprises a plurality of inner ring segments split in the axial direction, wherein a row of guide vane receptacles is formed in at least one of the inner ring segments for receiving the blade roots of the group of adjustable guide vanes.

[0013] The guide receptacles have a guide, i.e., a closer connection, at least in one direction, to the adjustable guide vanes arranged therein, with less play than the clearance receptacles. The guide receptacles advantageously create a closer connection between the guide receptacles and the guide vanes arranged in the guide receptacles, which essentially leads to a more direct power transmission between the guide receptacles and the corresponding guide vanes, in particular the guide vanes.This allows the inner ring and its inner ring segments to be better adapted to the prevailing temperatures through the clever placement of the guide mounts in the row of guide vane mounts. This reduces temperature fluctuations and the resulting material expansion on the leakage gaps. At the same time, targeted and improved guidance of the inner ring position is achieved, increasing the overall efficiency of the aircraft engine. Furthermore, with an inner ring better adapted in this way, cording is also reduced, which in particular reduces wear between the inner ring segments and thus has a positive impact on service life. It goes without saying that the clearance mounts also have such a small gap to the guide vanes arranged within them that aerodynamic losses are kept to a minimum.

[0014] The inner ring can be designed, in particular, for a stator stage of a compressor. However, it is also conceivable for the inner ring to be designed for a stator stage of a turbine. The inner ring serves—as already described in the introductory section—to create an inner air seal and forms part of an inner casing of a core flow duct of the aircraft engine. The number of guide vane receptacles can be the same in all inner ring segments. The guide vane receptacles are essentially complementary to the corresponding blade roots to be accommodated in them and can preferably be precisely fitted in the axial direction and / or in the circumferential direction. The blade roots of the guide vanes of the guide vane ring can have at least one first outer plate facing the core flow duct and a blade pin arranged radially inwardly therefrom.Accordingly, the guide vane receptacles can be designed with a corresponding outer disk seat and pin seat in a complementary manner. One of the adjustable guide vanes and a guide vane receptacle receiving this guide vane form a sliding pair and are sliding partners. Such a connection formed as a sliding pair, consisting of the guide vanes and the guide vane receptacles, can comprise a sliding device, in particular a sliding bushing and / or sliding coating. The sliding device can be part of one or both sliding partners. At least either the guide vanes or at least the guide vane receptacles, or both sliding partners, can completely or at least partially encompass the sliding device. The inner ring segment can be formed from at least two inner ring segment sections that abut one another in the axial direction.Both the terms "axially split inner ring" and "axially split inner ring segment" also encompass embodiments that, due to the division of the inner ring or the inner ring segment, have contact surfaces that do not extend in the radial direction or only partially extend in the radial direction. Preferably, the row of guide vane receptacles can be evenly distributed along a circumferential extent of the inner ring segment between a first end and a second end of the inner ring segment. In particular, all guide vane receptacles of the inner ring can be evenly distributed in the circumferential direction.

[0015] Further advantages and features emerge from the following description of some preferred embodiments and the dependent claims.

[0016] In an advantageous embodiment of the invention, the row of guide vane receptacles comprises precisely two guide receptacles. The guide vane ring forms a suspension system, with the inner ring suspended from the guide vanes. By arranging precisely two guide receptacles, the guide vane suspension system is completely defined, which advantageously further reduces deflection. Alternatively or additionally, a guide vane ring comprising the inner ring can have precisely two guide vanes, which are arranged with a precise fit in the guide vane receptacles provided for them.

[0017] In a further advantageous embodiment of the invention, the at least one guide receptacle in the row is arranged adjacent to two clearance receptacles. This arrangement allows for even more precise guidance of the inner ring on the guide vanes, while simultaneously providing a clearance that allows for material expansion in a predetermined and thus advantageously largely harmless manner.

[0018] In an advantageous development of the invention, a guide receptacle is arranged at a second location in the row of guide vane receptacles and / or at a second-to-last location in the row of guide vane receptacles. By arranging at least one clearance receptacle circumferentially on the outside in the row of guide vane receptacles, deflection is advantageously and optimally reduced.

[0019] Furthermore, in a further advantageous embodiment of the invention, it can be provided that only guide receptacles in the row of guide vane receptacles have an inner plate seat for an inner plate of the guide vanes. This configuration requires that the group of guide vanes comprises at least one clearance guide vane and at least one guide vane different from the at least one clearance guide vane, and that the at least one guide vane is designed differently from the at least one clearance guide vane with regard to the geometry of the blade roots, and that at least one blade root of the at least one guide vane has an inner plate.This configuration advantageously allows the guide vanes to be arranged closer to one another, since the guide vanes form a guide vane array at an angle to one another in the circumferential direction, and the space used radially inward by the guide vanes in the inner ring represents the limiting factor in this regard. This advantageously allows for the creation of improved guide vane ring geometries. The inner plates, blade pins, and outer plates described herein can be substantially cylindrical, with the blade pin, in particular, having a smaller cylinder diameter than the blade plates, i.e., the corresponding inner plate and outer plate.

[0020] A further advantageous embodiment of the invention requires that the blade roots arranged in the row of guide vane receptacles have at least one first outer plate facing a core flow duct of the aircraft engine and a blade journal located radially inward therefrom, and that the blade roots are each formed with an inner plate arranged radially inward on the blade journal and opposite the outer plate. In the advantageous embodiment, the at least one guide receptacle can then be designed differently from the at least one clearance receptacle with regard to radial gaps between the outer plates and / or the inner plates of the blade roots to be accommodated, on the one hand, and the guide vane receptacles, on the other hand.The differently designed radial gaps allow the thermal displacements occurring along the circumferential extent of the inner ring or the inner ring segment to be compensated even better, since the geometries of the different guide vane mounts can be adapted to the prevailing temperatures or to the thermal stresses occurring in the components.

[0021] In a further advantageous embodiment of the invention, the radial gaps in the guide receptacles are designed to be minimal in terms of radial size and manufacturing tolerances, so that the guide receptacle and a guide vane to be arranged therein are designed to fit each other precisely in the radial direction. This advantageously creates a bearing seat for the adjustable guide vanes on the inner ring that fits precisely in the radial direction, so that any displacement of the inner ring via the guide vanes is guided radially immediately and directly. This greatly reduces cording. The remaining guide vanes are advantageously mounted in the clearance receptacles in a floating manner in the radial direction, so that no radial forces are transmitted via them. This largely compensates for thermal deformation of the inner ring.

[0022] In a preferred embodiment of the invention, the inner ring is formed in the circumferential direction from at least three inner ring segments, in particular from at least four inner ring segments, particularly preferably from at least five or more inner ring segments. The inner ring segments are arranged in a row in the circumferential direction. The division of the inner ring in the circumferential direction advantageously prevents bending of the inner ring. Deflecting and / or other types of bending are advantageously better reduced.

[0023] In a further preferred embodiment of the invention, each inner ring segment has between five and twelve guide vane receptacles in the respective row of guide vane receptacles. Due to the small number of guide vanes, the inner ring segments can be easily mounted to the guide vanes or vice versa. More or fewer guide vane receptacles in an inner ring segment are also conceivable. The inner ring segments can also have different numbers of guide vane receptacles. Preferably, between six and eleven guide vane receptacles are provided in each inner ring segment. Particularly preferably, between eight and ten guide vane receptacles are provided in each inner ring segment.

[0024] In a particularly advantageous embodiment, the inner ring is further developed such that the inner ring further comprises a seal carrier consisting of several seal carrier segments, the seal carrier forms a radially inner stop on one or more of the guide vane receptacles from the row of guide vane receptacles for the blade roots of the guide vanes, and / or the circumferential end faces of the inner ring segments and the circumferential end faces of the seal carrier segments are arranged offset from one another. This further reduces unfavorable curvatures, and the seal carrier and inner ring segment advantageously support each other against bending.

[0025] A second aspect of the invention relates to an adjustable guide vane ring for an aircraft engine, comprising at least one group of adjustable guide vanes with blade roots and an axially split inner ring receiving the blade roots of the adjustable guide vanes, in particular one of the axially split inner rings described above, wherein the inner ring is formed from a plurality of inner ring segments, and wherein at least one, in particular each, of the plurality of inner ring segments has a row of guide vane receptacles for receiving the blade roots of the at least one group of guide vanes.The guide vane stage achieves the object in that the at least one group of guide vanes comprises at least one guide vane which is designed differently from the other guide vanes, in particular the clearance guide vanes, in the group of guide vanes with regard to a geometry forming a connection between the guide vane receptacles and the blade roots, and / or in that the row of guide vane receptacles comprises at least one guide receptacle which is designed differently from the other guide vane receptacles, in particular the clearance receptacles, in the row of guide vane receptacles with regard to the geometry forming the connection between the guide vane receptacles and the blade roots.

[0026] Due to the different connections of the guide vanes and guide vane mounts, the adjustable guide vane ring can respond very well to the thermal conditions, reduces leakage compared to a guide vane ring known from the state of the art and thus improves the efficiency of the aircraft engine.

[0027] In a further advantageous embodiment of the adjustable guide vane ring, it is provided that one of the guide vane receptacles and one of the blade roots form a sliding connection as sliding partners, and that at least one of the sliding partners has a sliding device, in particular a bushing or a coating. A sliding device, in particular a bushing or coating, further improves the sliding properties of the sliding partners and thus, on the one hand, reduces wear, so that the service life increases, and on the other hand, reduces leakage, since closer tolerances can be maintained. Bushings can be provided in a split design. The bushings can be axially split and, during assembly, arranged together with the inner ring segment sections on the blade roots. They can also be provided together with the guide vanes, in which case the inner ring segment sections are arranged around the bushings.

[0028] In the sense of the present invention, the sliding device is considered to be part of the guide vane or the guide vane receptacle, and can accordingly also form part of the fit or the entire fit of the guide vane in the guide receptacle or part of the fit or the entire fit of the guide receptacle around or in the guide vane.

[0029] In a particularly advantageous embodiment of the guide vane ring, the guide receptacles each have an inwardly projecting cantilever flange arranged radially between an inner plate and an outer plate of the guide vane arranged in the respective guide receptacle. A minimal clearance and / or minimal radial gap is formed between the cantilever flange on the one hand and the inner plate and the outer plate on the other hand, in particular with a precise fit. It can be provided that only the guide receptacles have a precisely fitting cantilever flange between the inner plate and the outer plate.It can be provided that the clearance guide vanes also have a cantilever flange which is arranged in the radial direction between an inner plate and an outer plate of the clearance guide vane arranged in the respective clearance receptacle, wherein a clearance and / or gap is formed between the cantilever flange of the clearance receptacle on the one hand and the inner plate and the outer plate of the corresponding clearance guide vane on the other hand.

[0030] In a further preferred embodiment of the guide vane ring, it is provided that the at least one group of guide vanes comprises at least two guide vanes, and / or that in the row of guide vane receptacles at least two clearance guide vanes are arranged adjacent to the at least one guide vane and / or that a guide vane is arranged at a second location in the row of guide vane receptacles and / or at a penultimate location in the row of guide vane receptacles. Due to the specific design of the combinations of guide vanes and guide vane receptacles proposed here, the thermal expansion of the guide vane ring can be advantageously reduced and / or compensated. Furthermore, the inner ring can be better guided on the guide vanes in the radial direction, so that any curvature of the inner ring segments is advantageously reduced.

[0031] A third aspect of the invention relates to an aircraft engine with an adjustable guide vane ring, in particular with an adjustable guide vane ring as described above, and / or with an axially split inner ring as described above.

[0032] The invention is explained in more detail with reference to the following drawings using some preferred embodiments of the invention. Fig. 1 shows a meridian section of an aircraft engine with a first embodiment of a guide vane ring according to the invention with an inner ring according to the invention. Fig. 2 shows a cross section of a second embodiment of a guide vane ring according to the invention with an inner ring according to the invention. Fig. 3 shows a cross section of the second embodiment of the inner ring according to the invention. Fig. 4a shows a meridian section of a guide connection of a fourth embodiment of a guide vane ring according to the invention with an inner ring according to the invention. Fig. 4b shows a meridian section of a clearance connection of the fourth embodiment of a guide vane ring according to the invention with an inner ring according to the invention.

[0033] In Fig. 1An aircraft engine 1 is shown schematically in a meridional section. The aircraft engine 1 has an engine inlet 1a, from which a bypass duct 1b and a core flow duct 1c receive air flow downstream. The bypass duct 1b is used to generate thrust, while the core flow duct 1c is used primarily to generate energy for the components of the aircraft engine 1 and the cabin systems of an aircraft. The main components of the aircraft engine 1, namely a compressor 2, a combustion chamber 3, and a turbine 4, are arranged in sequence in the core flow duct 1c. The aircraft engine 1 has an outer casing 6 surrounding the engine inlet 1a and the bypass duct 1b, and an intermediate casing 7 separating the bypass duct 1b and the core flow duct 1c. A fan 5 for sucking in and initially compressing air is provided in the engine inlet 1a.The fan 5, the compressor 2, and the turbine 4 are mechanically coupled by means of at least one shaft 8 rotating about an engine rotation axis 8a, wherein the fan 5 and optionally also front low-pressure compressor stages (not shown) can be decoupled from the faster-running turbine 4 by a gearbox 9. A portion of the air sucked in and compressed by the fan flows into the core flow channel 1c, where it is highly compressed by the compressor 2 to be mixed with fuel and ignited in the combustion chamber 3 and finally to expand in the turbine 4 to drive the at least one shaft 8.

[0034] The aircraft engine 1 and its components are described in a shaft-fixed cylindrical coordinate system comprising an axial direction Ax, a radial direction R, and a circumferential direction U.

[0035] In Fig. 1Two exemplary embodiments of a guide vane ring 2a, 4a according to the invention are shown, each with a group of guide vanes 20, 20' and an inner ring 10 according to the invention. A first exemplary embodiment is designed as a compressor guide vane ring 2a in the compressor 2, and a second exemplary embodiment is designed as a turbine guide vane ring 4a in the turbine 4. It is understood that the group of guide vanes 20, 20' and the inner rings 10 of the compressor guide vane ring 2a and the turbine guide vane ring 4a differ from one another. In the following description, the invention is described in more detail using a guide vane ring 2a, 4a designed as a compressor guide vane ring 2a.

[0036] In Fig. 2 and Fig. 3The first embodiment of a guide vane ring 2a is schematically illustrated in a cross-section through the guide vane ring 2a and is explained in more detail in the following description. The guide vane ring 2a comprises an inner ring 10 and a group of guide vanes 20, 20'. Fig. 2 only a rear inner ring segment section 13 of a single inner ring segment 11 of the inner ring 10 is shown. The inner ring 10 consists of a plurality of inner ring segments 11 that are arranged in a row in the circumferential direction U. The illustrated inner ring segment 11 has a row of guide vane receptacles 15, 15', in which the group of guide vanes 20, 20' are received with their blade roots 21, 21' and each form a sliding connection, wherein the guide vanes 20, 20' are pivotably and thus adjustablely arranged in the guide vane receptacles 15, 15'.

[0037] The blade roots 20, 20' of all guide vanes in the group of guide vanes 20, 20' are formed with an outer plate 22, 22', which, together with an outer surface of the inner ring segment 11, forms part of an inner casing of the core flow channel 1c. In order to accommodate the outer plates 22, 22', the guide vane receptacles 15, 15' each have an outer plate seat 15a, 15a', which is complementary to the outer plate 22, 22'. A blade pin 23, 23' is arranged radially inwardly on the respective outer plate 22, 22', wherein the blade pin 23, 23' has a smaller diameter than the respective outer plate 22, 22'. The guide vane receptacles 15, 15' have corresponding outer plate seats 15a, 15a' and journal seats 15b, 15b', which form a sliding connection with the blade roots 21, 21', in particular the outer plates 22, 22' and the blade journals 23, 23' as sliding partners.The possible connecting surfaces of the sliding partners are designed with a sliding coating as a sliding device in order to improve the friction and sliding properties of the sliding partners.

[0038] In the present exemplary embodiment, two types of guide vanes and two types of guide vane receptacles are shown, namely clearance guide vanes 20 and guide vanes 20', as well as corresponding clearance receptacles 15 and guide receptacles 15' in the inner ring 10. The clearance guide vanes 20 are suspended in the clearance receptacles 15, meaning that a slight radial movement of the clearance guide vanes 20 is possible. As a result, the inner ring 10 can very well compensate for expansions and displacements due to high temperatures during the operating state of the aircraft engine 1. In contrast to the clearance guide vanes 20, the guide vanes 20' in the present exemplary embodiment additionally have an inner plate 24' radially on the inside of their blade roots 21', which is arranged in a complementarily designed inner plate seat 15c' of the guide receptacle 15'.This means that only guide receptacles 15' have an inner disc seat 15c' for an inner disc 24' of the guide vanes 20'. This design has the additional advantage that the inner ring segments 11 are more stable in the inner radial region and the guide vanes can be arranged closer together on the inside. The outer disc seat 15a' and the inner disc seat 15c' delimit a pin seat 15b' arranged between the disc seats, which protrudes as an inner flange between the discs and forms radial gaps 16', 17' with the discs 22', 24' of the guide vane 20'. The radial gaps are designed to be minimal in terms of their radial size and tolerances, so that radial movement of the guide vane 20' in the guide receptacle 15' is hardly possible, in contrast to the floatingly mounted clearance guide vanes 20 in the clearance receptacles 15.In the event of a radial change in the length of the guide vanes, in particular the guide vanes, or in the event of expansion in the intermediate casing 7 serving as the outer casing of the core flow channel 1c, the guide vanes 20' directly guide the inner ring 10 in operative connection with the guide receptacles 15'. The inner ring segment 11 thus has a tight fit in the radial direction and is guided in the radial direction by the guide vanes 20'.

[0039] As in Fig. 3As shown, exactly two guide receptacles 15' are arranged in the row of guide vane receptacles 15, 15', namely in the second position and (not shown) in the penultimate position of the row. Adjacent to the two guide receptacles 15', clearance receptacles 15 are arranged in the row of guide vane receptacles 15, 15'. This results in the connection of the inner ring to an outer casing, i.e., the intermediate casing 7 of the core flow channel 1c, being statically determined. This advantageously avoids indeterminate, in particular overdetermined, guidance of the inner ring segment 11 on the guide vanes 20, 20'.

[0040] The inner ring segment 11 extends over an angle α, which in the present embodiment is 90°, so that the inner ring 10 is composed of four inner ring segments 11. The inner ring segments 11 can extend over a different angle, for example, over 120° or 60°. The number of inner ring segments can be varied accordingly. The inner ring segments 11 each have a row of eight guide vane receptacles 15, 15'. Accordingly, the group of guide vanes 20, 20' also comprises eight guide vanes 20, 20'.

[0041] Fig. 4a and Fig. 4b show a third embodiment of a guide vane ring 2a according to the invention. Fig. 4a a first meridian section through a guide vane 20' and guide receptacle 15' and in Fig. 4bA second meridian section through a clearance guide vane 20 and a clearance receiver 15 is shown in a schematic representation. The inner ring 10 is formed from a plurality of inner ring segments 11, which are formed from a front inner ring segment section 12 in the axial direction Ax and a rear segment section 13. The segment sections 12, 13 abut one another in the axial direction Ax and are fastened to one another by screws or bolts.

[0042] In contrast to the second embodiment, the clearance guide vanes 20 also have an inner plate 24. This has the advantage that the radial movement of the clearance guide vanes 20 in the clearance receptacles 15 is also limited.

[0043] To form the sliding connection, the blade roots 21, 21' each comprise sliding devices 30, 30' designed as bushings 30, 30', which are arranged between the blade roots 21, 21' and the guide vane receptacles 15, 15'. On the blade roots 21' of the guide vanes 20', the bushings 30' have guide flanges 31', which are arranged with a precise fit in the radial direction R between the outer plates 22' and the inner flange 15d', as well as between the inner flange 15d' and the inner plate 24'. As a result, the guide vane 20' can pivot easily in the guide receptacle 15', since less friction occurs due to the bushing 30', but at the same time a radial relative movement between the guide receptacle 15' and the guide vane 20' is largely prevented, so that the inner ring 10 can be moved directly in the radial direction R by the guide vanes 20'.

[0044] The bushings 30 between the clearance receivers 15 and the clearance guide vanes 20, however, do not have guide flanges and are somewhat shorter in the radial direction R, so that small gaps 16, 17 are formed between the bushing 30 and the blade plates 22, 24 of the clearance guide vane 20. The gaps 16, 17 serve as radial clearance between the blade plates 22, 24 and an inner cantilever flange 15d, so that the clearance guide vanes 20 can move radially in the clearance receiver 15 despite the blade plates 22, 24.

[0045] Furthermore, in the third exemplary embodiment, the inner ring 10 is provided with a seal carrier 14 consisting of a plurality of seal carrier segments 14a, which is inserted radially inward and axially between the two inner ring segment sections 12, 13, and which forms a radially inward stop 14b on the guide vane receptacles 15, 15' for the blade roots 21, 21' of the guide vanes 20, 20'. On the seal carrier 14, run-in linings 14c are formed or fastened radially inward to form a seal with one or more sealing fins (not shown) running into the run-in linings 14c of a radially inward rotating rotor (not shown).

[0046] In the circumferential direction, the seal carriers have an approximately identical circumferential extent as the inner ring segments, but are arranged offset relative to them in the circumferential direction, so that the circumferential end faces of the inner ring segments 11 and the circumferential end faces of the seal carrier segments 14a are arranged offset relative to one another. List of reference symbols

[0047] 1 Aircraft engine 1a Engine inlet 1b Bypass duct 1c Core duct 2 Compressor 2a Compressor vane ring, compressor nozzle ring 3 Combustion chamber 4 Turbine 4a Turbine vane ring, turbine nozzle ring 5 Fan 6 Engine outer casing 7 Intermediate casing 8 Shaft(s) 8a Engine rotation axis 9 Gearbox 10Inner ring 11Inner ring segment 12Front inner ring segment section 13Rear inner ring segment section 14Seal carrier 14aSeal carrier segments 14bInlet seal 14cStop 15Vent vane holder 15'Guide holder 15a, 15a'Outer disc seat 15b, 15b'Tail seat 15c, 15c'Inner disc seat 15d, 15d'Cantilever flange 16Radial gap 16'Radial gap (exact fit) 17Radial gap 17'Radial gap (exact fit) 18'Cantilever flange (exact fit) 20Vent vane, in particular compressor vane 20'Guide vane 21, 21'Blade root 22, 22'Outer disc 23, 23'Blade journal 24, 24' inner plate 30, 30' bushing / coating 31' guide flange 40Inner air seal AxAxial direction RRadial direction UCircumferential direction αAngle

Claims

1. Axially split inner ring segment (11) for an adjustable guide vane ring (2a, 4a) of an aircraft engine (1), wherein the guide vane ring (2a, 4a) has a group of adjustable guide vanes (20, 20'), and wherein the guide vanes (20, 20') each have a blade root (21, 21'), wherein the inner ring segment (11) has a series of guide vane receptacles (15, 15') for receiving the blade roots (21, 21') of the group of adjustable guide vanes (20, 20'), characterized by that the row of guide vane receptacles (15, 15') comprises at least one clearance receptacle (15) and at least one guide receptacle (15') different from the at least one clearance receptacle (15), and that the at least one guide receptacle (15') is designed differently from the at least one play receptacle (15) with regard to a geometry for receiving the blade roots (21, 21').

2. Inner ring segment (11) according to claim 1, characterized by thatthe row of guide vane holders (15, 15') comprises exactly two guide holders (15').

3. Inner ring segment (11) according to one of the preceding claims, characterized by that the at least one guide receptacle (15') is arranged in the row adjacent to two play receptacles (15).

4. Inner ring segment (11) according to one of the preceding claims, characterized by that a guide receptacle (15') is arranged at a second position in the row of guide vane receptacles (15, 15') and / or at a penultimate position in the row of guide vane receptacles (15, 15').

5. Axially split inner ring comprising a plurality of axially split and circumferentially arranged inner ring segments according to one of the preceding claims, characterized by thatthe inner ring (10) is formed in the circumferential direction (U) from at least three inner ring segments (11), in particular from at least four inner ring segments (11), particularly preferably from at least five or more inner ring segments (11).

6. Axially split inner ring according to claim 5, characterized by that each inner ring segment (11) in the row of guide vane receptacles (15, 15') has between five and twelve guide vane receptacles (15, 15').

7. Axially split inner ring according to claim 5 or 6, characterized by that the inner ring (10) further comprises a seal carrier (14) consisting of a plurality of seal carrier segments (14a), that the seal carrier (14) forms a radially inner stop on one or more of the guide vane receptacles (15, 15') from the row of guide vane receptacles (15, 15') for the blade roots (21, 21') of the guide vanes (20, 20'), and / or thatthe circumferential end faces of the inner ring segments (11) and the circumferential end faces of the seal carrier segments (14a) are arranged offset from one another.

8. Adjustable guide vane ring (2a, 4a) for an aircraft engine (1), comprising at least one group of adjustable guide vanes (20, 20') with blade roots (21, 21') and an axially split inner ring (10) receiving the blade roots (21, 21') of the at least one group of adjustable guide vanes (20, 20'), in particular an axially split inner ring (10) according to one of claims 5 to 7, wherein the inner ring (10) is formed from a plurality of inner ring segments (11), wherein at least one, in particular each, of the plurality of inner ring segments (11) has a row of guide vane receptacles (15, 15') for receiving the blade roots (21, 21') of the at least one group of guide vanes (20, 20'), wherein the group of guide vanes (20, 20') has at least one clearance guide vane (20) and at least one guide vane (20') different from the at least one play guide vane (20),wherein the at least one guide vane (20') is designed differently from the at least one clearance guide vane (20) with regard to a geometry of the blade roots (21, 21'), and wherein the blade root (21') of the at least one guide vane (20') has an inner plate (24'), , characterized by that only guide receptacles (15') in the row of guide vane receptacles (15, 15') have an inner plate seat (15c') for an inner plate (24') of the guide vanes (20').

9. Adjustable guide vane ring (2a, 4a) according to claim 8, wherein the blade roots (21, 21') arranged in the row of guide vane receptacles (15, 15') have at least one first outer plate (22, 22') facing a core flow channel (1b) of the aircraft engine (1) and a blade journal (23, 23') located radially inward therefrom, and wherein the blade roots (21, 21') are each formed with an inner plate (24, 24') arranged radially inward on the blade journal (23, 23') and opposite the outer plate (22, 22'), characterized by that the at least one guide receptacle (15') is designed differently from the at least one clearance receptacle (15) with regard to radial gaps (16, 17, 16', 17') between the outer plates (22, 22') and / or the inner plates (24, 24') of the blade roots (21') to be accommodated, on the one hand, and the guide vane receptacles (15, 15') on the other hand.

10. Adjustable guide vane ring (2a, 4a) according to claim 9, characterized by thatthe radial gaps (16', 17') in the at least one guide receptacle (15') are designed to be minimal with respect to a radial extent and with respect to manufacturing tolerances, so that the at least one guide receptacle (15') and a guide vane (20') to be arranged in it are designed to fit one another precisely in the radial direction.

11. Adjustable guide vane ring (2a, 4a) according to one of claims 8 to 10, characterized by that in each case one of the guide vane receptacles (15, 15') and one of the blade roots (21, 21') form a sliding connection as sliding partners and that at least one of the sliding partners has a sliding device (30, 30'), in particular a bushing or a coating.

12. Adjustable guide vane ring (2a, 4a) according to one of claims 8 to 11, characterized by thatthe guide receptacles (15') each have an inwardly projecting cantilever flange (15d') which is formed in the radial direction (R), in particular with a precise fit, between an inner plate (22') and an outer plate (24') of the guide vane (20') arranged in the respective guide receptacle (15'), and that a minimal play and / or minimal gap (16', 17') is formed between the cantilever flange (15d') on the one hand and the outer plate (22') and the inner plate (24') on the other hand.

13. Adjustable guide vane ring (2a, 4a) according to one of claims 8 to 12, characterized by thatthe group of guide vanes (20, 20') comprises at least two guide vanes (20'), and / or in the row of guide vane receptacles (15, 15') at least two play guide vanes (20) are arranged adjacent to the at least one guide vane (20') and / or that a guide vane (20') is arranged at a second position in the row of guide vane receptacles (15, 15') and / or at a penultimate position in the row of guide vane receptacles (15, 15').

14. An aircraft engine (1) having a guide vane ring (2a, 4a) according to claims 8 to 13, an inner ring according to one of claims 5 to 7 and / or having an inner ring segment (10) according to one of claims 1 to 4.

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