EP3176384A1 - Inner shroud, corresponding inner shroud sector, vane assembly and turbomachine - Google Patents

Abstract

An inventive inner ring 10 for a vane ring of a turbomachine has a radially outer inner ring surface 11 and a plurality of receptacles 12 for each one Leitschaufelteller 21 a of a guide vane 20. The receptacles 12 each have an opening 13 in the outer inner ring surface 11 and a bottom surface 14 located radially opposite the opening. At least two of the receptacles 12 are separated from one another by a partition wall 15 and joined together in an area of their bottom surface 14 by an opening 16. A guide vane ring 100 according to the invention for a turbomachine has an inner ring 10 according to the invention and a plurality of guide vanes 20 inserted into the receptacles 12.

Description

The invention relates to an inner ring for a vane ring, an inner ring sector for an inner ring, a vane ring with an inner ring and a plurality of vanes and a turbomachine with a vane ring.

Turbomachines, such as aircraft engines and stationary gas turbines, often have at least one compressor-side vane row with a plurality of vanes for setting optimum operating conditions. The vane row forms an inner ring with a so-called vane ring. Preferably, the guide vanes are pivotable about their longitudinal axis.

The actuation of the adjustable guide vanes can be effected via radially outwardly mounted adjusting pins of the guide vanes, wherein the adjusting pins can interact with a corresponding adjusting device on the outer housing. On the inner ring, a seal carrier is preferably guided, which is provided with sealing elements or inlet pads, facing the rotor-side sealing ribs.

The inner ring preferably has a plurality of receptacles extending in the radial direction, in each of which a guide plate of a guide vane is or can be inserted. The radially inner end of a vane is stabilized by such a guide plate arranged in the receptacle. The axis of rotation of the Verstellleitschaufel is perpendicular to the central axis of the vane ring or its inner ring. The vane plate may have a journal on its radially inner side, and the receptacle may be configured to receive this journal together with a mating sleeve.

The receptacles in the inner ring are separated from each other in the circumferential direction by respective partitions extending in the axial direction. In the manufacture of the inner ring and in the operation of the vane ring there is a risk that such a partition partially yields and is pressed into an adjacent receptacle, which therefore no longer has its exact shape; this can be a scheduled recording of a Guide vane and / or pivoting of the vane obstruct or at least hinder. Also in operation, the partition can be bent in the direction of an adjacent receptacle and thus affect the pivotability of a guide blade inserted therein.

In order to reduce the risk of such deformation of the recordings, therefore, conventional inner rings are made with a minimum wall thickness for the partitions, which must have these at their thinnest points.

For a given inner ring circumference, the number of slots for the guide paddle (and thus the number of mountable guide blades) is determined by the given paddle sizes and the minimum wall thickness to be maintained. These parameters thus have a restrictive effect on a design of the turbomachine with a large number of pivotable guide vanes or large guide vanes. However, such a design and / or a minimum size of the guide blade plates is often aerodynamically and / or structurally advantageous.

The publication WO 2014/078 121 A1 discloses an arrangement in which the receptacles are not separated from each other by partitions, but the recesses for the guide blade plates are arranged to merge into one another on a radially outer inner ring surface.

This has the disadvantage of increased leakage between the receptacles for and through the vanes. In addition, a centering of the stator blades may be unstable in such an arrangement.

The object of the present invention is to provide an inner ring or an inner ring sector or a turbomachine with stable centering and low leakage, wherein, for a given circumference, the guide vane ring has an aerodynamically and / or structurally improved design.

The object is achieved by an inner ring according to claim 1, by an inner ring sector according to claim 7, by a vane ring according to claim 8 and by a turbomachine according to claim 10. Advantageous embodiments are disclosed in the subclaims, the description and the figures.

An inner ring according to the invention for a vane ring of a turbomachine has a radially outer inner ring surface and a plurality of receptacles for a respective vane plate of a (preferably pivotable) vane; The terms "radial" and "axial" refer in this document - unless otherwise stated - always on a central geometric axis of the inner ring, which is not always specially formulated for readability; The same applies to the term "circulation direction". The receptacles each have an opening in the radially outer inner ring surface and (at least) one of the opening radially opposite bottom surface. At least two of the receptacles are separated (in the direction of rotation) by a partition wall and connected together in an area of the bottom surfaces of the receptacles by an opening; the at least two receptacles are preferably arranged adjacent in the direction of rotation of the inner ring.

The at least one bottom surface of a receptacle of an inner ring according to the invention thus lies radially further inward than the radially outer inner ring surface and radially through the opening faces an environment of the inner ring. When the guide blade plate is not inserted, the bottom surface is visible from the outside when viewed radially (inwards). In particular, such a bottom surface can form a stop for a stator blade to be inserted in the receptacle in the radial direction.

The receptacles may each be adapted to accommodate a Leitschaufelteller to be used with an optionally arranged thereon journal, possibly also a bearing bushing for such a journal. The at least one bottom surface may form a stop surface for the bearing journal or for a bearing bush for the bearing journal to be radially inserted into the receptacle, or at least one bottom surface and / or at least partially delimited by it may be another Opening of a recess may be formed, which may for example be adapted to receive a journal of the guide vane.

An inner ring sector according to the invention (which may, for example, be in the form of a half, a third or a quarter ring) is adapted to be assembled with at least one further inner ring sector to form an inner ring according to the invention according to one of the embodiments disclosed in this document. It comprises at least two receptacles of the (assembled according to the invention) inner ring which are separated from one another by a dividing wall and joined together in an area of their bottom face by an opening.

An inventive vane ring for a turbomachine has an inner ring according to one of the embodiments disclosed in this document and a plurality of guide vanes inserted into the receptacles.

A turbomachine according to the invention comprises a guide vane ring according to the invention.

An inner ring according to the invention, an inner ring sector according to the invention, a guide vane ring according to the invention and a turbomachine according to the invention enable secure, stable centering of the guide blade plates in their respective receptacles with reduced leakage.

In addition, they advantageously enable an arrangement of guide vanes, in which a distance between adjacent guide vanes or bearing bushes minimized and nevertheless the risk of deformation of a receptacle can be avoided: in particular if two adjacent receptacles have circular cylindrical shaped sections, they run radially inwardly toward each other to. In the area of their bottom surfaces they therefore have a minimum distance from each other. According to the present invention, no minimum distance needs to be maintained in this area in order to prevent an excessively thin partition wall from unfavorably deforming in this area. According to the invention, in this narrowest area there is a breakthrough between the receptacles, so that a dividing wall, which could deform, is not there. Radially further out, on the other hand, where the circular cylindrical sections of the receptacles are further apart, they are separated from each other by a partition; This allows a secure and stable storage of used guide vanes or bushings for vanes.

In particular, such an inner ring allows an improvement in the efficiency and durability of a turbomachine.

Preferably, the at least two receptacles each comprise a substantially circular cylindrical portion (e.g., a circular cylindrical bore) in the inner ring which extends radially with respect to the inner ring. Such recordings can record correspondingly shaped guide plate or bearing bushes with a circular cylindrical section, which allows a particularly secure and stable storage and pivoting of the guide vanes.

According to an advantageous embodiment, the at least two seats (in the circumferential direction) along the radially outer inner ring surface (at its or one of its narrowest point (s)) have a distance of at most 3 mm, more preferably at most 2 mm from each other.

Thus, in the receptacles in the inner ring, a large number of vanes of a respective advantageous Leitschaufeltellergröße be used, and the partition is strong enough not to be deformed.

A variant embodiment is advantageous in which the dividing wall between the at least two receptacles extends radially from the radially outer inner ring surface at least 2 mm, more preferably at least 3 mm, into the inner ring.

According to an advantageous embodiment, the aperture between the at least two receptacles has a radial height of at least 2 mm, more preferably at least 3 mm; the radial height is starting from the bottom surface (or from one of the bottom surfaces, if there are several) to measure radially outward.

Thus, for example, in the case of shots with a circular cylindrical section and therefore a tapered from outside to inside partition a minimum thickness of the partition ensured by the radial extent of the partition to the inside (and thus the taper) is limited by the opening.

In the axial direction (relative to a central inner ring axis), the opening preferably has a width of at least 3 mm, more preferably at least 4 mm. In this way, an unfavorably small dividing wall thickness can be avoided laterally of a center of the aperture (for example located in a narrowest area between two receptacles).

The breakthrough may in the direction of rotation (relative to the inner ring) have a substantially triangular, circular section-shaped, circular or arch-shaped cross-section. Thus, the breakthrough can be optimized depending on a shape of the inner ring, for example, its size and / or its surface design. A triangular cross-section can be particularly easy to produce, for example, in the case of an axially split inner ring, because this only has to be beveled on the part rings to be assembled the partition; The same applies to an arched cross-section. In axially undivided inner ring, the production of a kreisabschnitt- or a circular arc-shaped cross-section may be associated with less effort. In addition, the avoidance of a central tip associated with such cross sections can advantageously reduce leakage in this area.

According to an advantageous embodiment, an inner ring according to the invention comprises two inner ring parts (for example partial rings) which are assembled in the axial direction and each have an edge in the axial direction, which limits the plurality of receptacles in sections. The receptacles are thus arranged between the inner ring parts, which together form at least a part of a border for each receptacle.

Such two-part inner rings are particularly useful for inserting the vanes and are also produce relatively little effort. In particular, they facilitate forming the aperture in a partition of a Inner ring according to the invention, because this is particularly well accessible in not yet assembled inner ring parts.

Of the two inner ring parts may have a first (eg in the main flow direction rear) inner ring part on a second (eg front in the main flow direction) inner ring part facing side extending in the axial direction projection with a surface which preferably forms the bottom surface for the recordings, wherein the Projecting on an outer edge engages in an annular, extending in the axial direction of the second groove portion of the second inner ring.

The at least two receptacles of an inner ring according to the invention which are connected through the aperture are preferably so arranged that at least two of the inserted guide vanes in the region of the aperture (eg in the region of the bottom surfaces) have a distance (at their or a narrowest point) of not more than 0.5 mm (in the direction of rotation). It is advantageous if the guide vanes are used without contact in said area, for example, have a distance of at least 0.1 mm.

Accordingly, at least two guide vanes (or their associated guide vanes) of a vane ring according to the invention preferably have a maximum spacing of 0.5 mm in the area of the aperture, more preferably in a range of 0.1 mm to 0.5 mm.

Thus, according to the invention, the guide vanes can be arranged close to one another, so that a large number of guide vanes with a suitable guide plate size can be inserted into the inner ring. The mentioned advantageous minimum distance of 0.1 mm prevents contact of the guide blade plates, otherwise obstructing the insertion and / or in use pivoting of the guide vanes could be impaired.

In embodiments in which the guide vanes have bearing journals which are inserted into bearing bushes and inserted into the receptacles together with them, the bearing bushes in the area of the aperture preferably have a spacing of a maximum of 0.5 mm (in the direction of rotation), more preferably in one area between 0.1 mm to 0.5 mm. Alternatively or additionally, the radial height of the aperture in embodiments with (possibly provided) bearing bushes is preferably at most as large as a shell height or thickness of the bearing bushes (ie at most as large as the extension of the bearing bushes used in - relative to the inner ring - radial direction ). Such height restriction of the aperture reduces leakage on the radially outer side of the bushings.

In the following preferred embodiments of the invention will be explained in more detail with reference to drawings. It is understood that individual elements and components can be combined differently than shown. Reference numerals for corresponding elements are used across figures and may not be rewritten for each figure.

Figur 1:

einen Abschnitt eines Leitschaufelkranzes in perspektivischer Darstellung;

Figur 2:

einen Abschnitt eines exemplarischen erfindungsgemäßen Innenrings mit eingesetzten Lagerbuchsen in einer Schnittdarstellung;

Figur 3:

einen Abschnitt eines Innenrings gemäß einer exemplarischen Ausführungsform der vorliegenden Erfindung;

Figur 4.

einen Abschnitt eines hinteren Teils eines beispielhaften erfindungsgemäßen Innenrings;

Figuren 5a, 5b:

je eine Explosionsdarstellung eines exemplarischen erfindungsgemäßen Innenrings mit Lagerbuchse und Leitschaufel.

They show schematically:

FIG. 1:

a section of a vane ring in perspective view;

FIG. 2:

a section of an exemplary inner ring according to the invention with inserted bushes in a sectional view;

FIG. 3:

a portion of an inner ring according to an exemplary embodiment of the present invention;

FIG. 4.

a portion of a rear portion of an exemplary inner ring according to the invention;

FIGS. 5a, 5b:

each an exploded view of an exemplary inner ring according to the invention with bearing bush and vane.

FIG. 1 shows a perspective view of a portion of a vane ring 100. This includes an inner ring 10 having a radially outer inner ring surface 11 and a plurality of receptacles 12, in each of which a stator blade 21a of a guide vane 20 is inserted; for better understanding, a picture without inserted guide vane is shown at the edge of the illustration. An intended main flow direction R extends axially from the image background through the inner ring 10 into the image foreground; the adverb "axial" is (as well as the adverb "radial") relative to an (abstract) central axis A of the inner ring 10 (and thus of the vane ring 100) to understand.

The vanes 20 include, in addition to the radially inward-positioned stator blade 21a, a radially outer-positioned stator blade 21b, which is intended to be fixed to a housing (not shown). Between the guide vanes 21a and 21b, an airfoil 22 is arranged. On the side facing away from the airfoil 22, the guide vanes 21b positioned radially outward have an adjusting pin 23 extending radially outwards.

Not recognizable in the representation of the FIG. 1 in that, according to the invention, the openings of the receptacles 12 on the inner ring surface 11 are each radially opposite a bottom surface 14, in the region of which at least two receptacles 12 are connected to one another by an opening 16. This is shown in the sectional view of FIG. 2 clear.

The FIG. 2 shows a portion of an inner ring 10 with an inner ring surface 11 and a plurality of receptacles 12 for (not shown) Leitschaufelteller. A bearing bush 30 has a radially inner annular surface 31, a radially outer annular surface 32 and a radially extending bore 33, which connects the two annular surfaces 31 and 32 with each other. In the receptacles 12, the bearing bushes 30 are used for (not shown) bearing journal of the respective stator blade in the example shown. The radially inner annular surface 31 of the bearing bush 30 rests on the radially outwardly facing bottom surface 14.

In the bore 33, the bearing pin 24 integrally formed on the radially inner surface 21c of the stator blade 21a is arranged later, so that the inner surface 21c rests on the radially outer annular surface 32 of the bearing bush 30; this is in the FIGS. 5a, 5b shown.

The receptacles 12 each have an opening 13 on the inner ring surface 11 and a bottom surface 14 which is opposite to the opening radially (relative to the inner ring axis); when not used Leitschaufelteller so the bottom surface is visible from the outside in the radial direction of view. In the illustrated example, the bottom surfaces 14 each form abutment surfaces for the bearing bushes 30. The bottom surfaces 14, the receptacles 12th Completely or partially terminate radially inward; in particular, they may themselves have openings (not shown).

Between each two adjacent receptacles 12, a partition wall 15 is arranged, which separates the recordings from each other; an extension d of the partition wall in the radial direction (relative to the inner ring) is (starting from the inner ring surface) preferably at least 2 mm, more preferably at least 3 mm. In particular, the extent d is preferably at least as great as the thickness (i.e., shell height) of a vane disk to be used (measured without a trunnion) so that it does not protrude from the inner ring surface 11 when inserted.

In an area of their bottom surface, adjacent receptacles 12 are connected to each other by an opening 16.

These openings 16 allow an advantageous arrangement of the bearing bushes (or in the receptacles 12 einzusetzender, in the FIG. 2 not shown Leitschaufelteller) while avoiding an unfavorably thin portion of the partition: As in the FIG. 2 can be seen, the cylindrical shaped receptacles are arranged radially in the inner ring. The distance between each two adjacent receptacles is thus reduced continuously radially inwards. The distance in the radially outer region (on the inner ring surface 11) is designated in the figure with a ₁ , the distance in the radially inner region (on the bottom surface 14) with a ₂ ; As can be seen in the figure, a ₁ > a ₂ . Preferably, a _{1 is} at most 3mm, more preferably at most 2mm. The distance a ₂ is advantageously less than or equal to 0.5 mm, more preferably between 0.1 mm to 0.5 mm.

Even with such a narrow arrangement of recordings, a correspondingly thin and therefore deformation-prone partition can be avoided according to the invention by arranging the opening 16 in the corresponding area. Its radial height h (starting from an adjacent bottom surface 14) is preferably at least 2 mm, more preferably at least 3 mm.

The radial height of the opening is preferably smaller than or equal to a thickness D of the bearing bushes 30 (ie their radial extent relative to the inner ring in the inserted state); As a result, leakage on a radially outer surface of the bushings and through the opening can be prevented or at least reduced.

In FIG. 3 a section of an axially two-part inner ring 10 according to the invention is shown. The inner ring 10 comprises a front inner ring part 10b (in the intended main flow direction) and a rear inner ring part 10a (in the intended main flow direction); This is also in the FIG. 4 shown in another view. The inner ring parts 10a and 10b are each formed as partial rings, ie in particular also as rings.

Front and rear inner ring part each have an edge 12b and 12a, which together enclose a plurality of receptacles and thereby each form a portion of their boundaries.

The edge 12a of the rear inner ring portion 10a has in the example shown in the limiting portion of each receptacle on a chamfer 17; it allows a correspondingly tightly guided on the inner ring pivotable vane.

On the side facing the front inner ring part, the rear inner ring part 10a has an axially extending projection 18, which engages at an outer edge in an annular and axially extending groove 25 of the front inner ring part 10b and has a surface, each having a Bottom surface 14 forms for the recordings. The bottom surfaces 14 are radially opposite the openings 13 of the receptacles 12. In this case, the bottom surface 14 forms the radially outwardly facing surface of the projection 18th

Neighboring receptacles are each separated in the region of the openings of the receptacles (in the inner ring surface) by a partition wall 15, which has a radial height d. In the area of the bottom surfaces 14, adjacent receptacles are connected to each other through an opening 16. The breakthroughs each have a radial height h, which is preferably in a range of 2mm to 3mm. In the example shown the breakthrough has a triangular cross-section. As described above, other cross-sectional shapes are possible, for example, circular section, round or arched. In particular, the breakthrough can be optimized depending on a shape of the inner ring, for example, its size and / or its surface design.

In the embodiment shown, the front and the rear inner ring part can be connected to one another via connecting elements 19.

In different perspectives, the show FIGS. 5a and 5b each an inner ring 10 according to an embodiment of the present invention with a guide vane 20 to be inserted in an exploded view. For an explanation of the individual elements analogous to the above figures, reference is made to their description. As continues in the FIG. 5b is characterized, the opening 16 in the axial direction (relative to a central inner ring axis, not shown) in the region of the bottom surface 16 formed by the projection 18 on a width b; Preferably, this width b is at least 3mm, more preferably at least 4mm. In this way too small a dividing wall thickness can also be avoided laterally of a center of the breakthrough (for example located in a narrowest area between two receptacles).

An inventive inner ring 10 for a vane ring of a turbomachine has a radially outer inner ring surface 11 and a plurality of receptacles 12 for each one Leitschaufelteller 21 a of a guide vane 20. The receptacles 12 each have an opening 13 in the outer inner ring surface 11 and a bottom surface 14 located radially opposite the opening. At least two of the receptacles 12 are separated from one another by a partition wall 15 and joined together in an area of their bottom surface 14 by an opening 16.

A guide vane ring 100 according to the invention for a turbomachine has an inner ring 10 according to the invention and a plurality of guide vanes 20 inserted into the receptacles 12.

reference numeral

10

inner ring

10a, 10b

Inner ring parts

11

Inner ring surface

12

admission

12a, 12b

receiving portion

13

Opening of the recording

14

floor area

15

partition wall

16

breakthrough

17

chamfer

18

head Start

19

connecting element

20

vane

21a, 21b

Leitschaufelteller

21c

radially inner surface

22

airfoil

23

adjustment peg

24

pivot

25

Groove in inner ring part

30

bearing bush

31

radially inner annular surface

32

radially outer annular surface

33

drilling

100

vane ring

A

central axis

D

Thickness of the bearing bush

R

intended main current direction

a ₁

Distance between two adjacent sockets

a ₂

Distance between two adjacent shots on the inner ring surface

b

Width of the aperture (in the axial direction)

d

radial extent of the partition

H

radial height of the breakthrough

Claims (11)

Inner ring (10) for a guide vane ring (100) of a turbomachine, wherein the inner ring has a radially outer inner ring surface (11) and a plurality of receptacles (12) for each one Leitschaufelteller (21 a) of a guide vane (20)
wherein the receptacles each have an opening (13) in the outer inner ring surface and a radially opposite the bottom surface (14), characterized in that
at least two of the receptacles (12) separated by a partition (15) and in an area of their bottom surface (14) by an opening (16) are interconnected. Inner ring according to claim 1, wherein the receptacles (12) each comprise a substantially cylindrical bore in the inner ring (10) which extends radially relative to the inner ring. Inner ring according to one of claims 1 or 2, wherein the at least two receptacles (12) along the radially outer inner ring surface (11) have a distance (a ₁ ) of at most 3mm, more preferably at most 2mm from each other. Inner ring according to any preceding claim, wherein the partition (15) between the at least two seats (12) extends from the radially outer inner ring surface (11) radially to 2mm, more preferably to 3mm into the inner ring (10)
and / or wherein the opening (16) between the at least two receptacles starting from the bottom surface (14) of one of the receptacles has a radial height (h) of at least 2 mm, more preferably at least 3 mm. Inner ring according to one of the preceding claims, wherein the opening (16) in the circumferential direction has a substantially triangular, circular section-shaped, circular or arched cross-section. Inner ring according to one of the preceding claims, comprising two axially formed inner ring parts (10a, 10b), each having an edge in the axial direction, which limits the plurality of receptacles in each case in sections. Inner ring according to claim 6, wherein of the two inner ring parts, a first inner ring part 10a on a side facing the second inner ring part (10b) has an axially extending projection (18) with a surface forming the bottom surface (14) for the receptacles, wherein the projection on an outer edge engages in an annular, axially extending groove (25) of the second inner ring part (10b). Inner ring sector for an inner ring (10) according to one of claims 1 to 7, wherein the inner ring sector at least two of a partition (15) separated from each other and in a region of its bottom surface (14) through an opening (16) interconnected receptacles (12) includes. Guide vane ring (100) for a turbomachine having an inner ring (10) according to one of the preceding claims and a plurality of in the receptacles (12) inserted vanes (20). Guide vane ring according to claim 9, wherein at least two of the inserted guide vanes (20) or used in the receptacles bearing bushes (30) for the guide vanes (20) in the region of the opening (16) have a distance (a ₂ ) of not more than 0.5 mm. Turbomachine with a vane ring (100) according to one of claims 9 or 10.

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