EP2696043A1 - Guide vane assembly and turbo engine - Google Patents

Abstract

The guide vane assembly has multiple rotatable guide vanes (2), where each guide vane is provided with an inner blade plate (16) and a bearing pin (18). The bearing pin is extended radially inwards from the inner blade plate and is inserted in an annular groove (32) in a section removed from the inner blade plate. The bearing bushes (8) are arranged between the inner blade plates and the annular grooves. The connecting elements (10) provided as spring rings are inserted in the separate annular grooves in a form-fitting manner. The annular grooves are provided with a tapered groove wall (36).

Description

The invention relates to a guide vane ring according to the preamble of patent claim 1 and a turbomachine.

Turbomachines such as aircraft engines and stationary gas turbines regularly have at least one compressor-side adjustable guide vane row with a large number of guide vanes which can be pivoted around their vertical axis or main axis in order to set optimum operating conditions. The adjustable or variable guide vane row forms a guide vane ring with an inner ring surrounding a rotor section. The inner ring is used for internal stabilization and storage of the guide vanes and has a plurality of radial bearing bores for receiving in each case a blade-side bearing journal. Since the thermal expansions of the vanes and the inner ring behave differently, gaps between the airfoils and the inner ring must be adjusted to avoid collisions between the vanes of the vanes and the inner ring. However, these so-called flag gaps reduce the efficiency of the turbomachine and shift their pumping limit adversely. To reduce the flag gaps, it is therefore customary to mechanically couple at least some vanes with the inner ring in the radial direction. A conventional type of connection provides to introduce in the bearing journal each have a circumferential groove and to engage in this an axial pin which is secured to the inner ring. A disadvantage of this type of connection, however, is that the introduction of force into the guide vanes is not centered, whereby additional moments burden the vanes.

In the European patent application EP 1 586 744 A2 a vane ring is shown, in which the guide vanes are fastened to the inner ring by means of a U-shaped bracket. The U-shaped bracket has two legs, with which it engages in an annular groove of the bearing pin. In addition, enforce the brackets bushings in which the journals are each performed. Although an improved introduction of force into the guide vanes takes place due to the U-shaped clamps, the bearing bushes, due to the lateral penetration of the clamps, have reduced guide surfaces for guiding the bearing journals.

In the US patent US 4,395,195 A a vane ring is shown, whose vanes are each led to several in a socket segment. For fixing the guide vanes in the bushing segments in the radial direction of the guide vane ring an annular groove is introduced in their respective bearing journal, engages in each of which a spring ring. Although the use of the spring rings, a central introduction of force into the guide vanes takes place, so that the generation of additional moments, which could load the guide vanes, is reduced. However, the tailor-made manufacture of the bushing segments is expensive to prevent misalignment of the vanes with each other.

The object of the invention is to provide a guide vane ring for a turbomachine, which eliminates the aforementioned disadvantages and allows a symmetrical and torque-free or virtually torque-free force introduction into the guide vanes. In addition, it is an object of the invention to provide a turbomachine with a high efficiency and a high surge limit.

This object is achieved by a guide vane ring with the features of patent claim 1 and by a turbomachine having the features of patent claim 6.

An inventive vane ring for a turbomachine has a plurality of rotatable vanes, each having an inner blade plate and a journal. The journal extends radially inwardly from the inner paddle and has an annular groove in a portion remote from the inner paddle. In addition, the vane ring has an inner ring for radially inner stabilization of the guide vanes, which has a plurality of radial bearing bores. Further, the vane ring has a plurality of bearing bushes which are arranged in the bearing bores and in which the bearing pins are guided. Furthermore, the vane ring connecting elements for releasably fixing at least individual vanes on the inner ring in the radial direction. According to the invention, the bearing bushes are arranged between the inner blade plates and the annular grooves and the connecting elements are spring rings which are inserted in a form-fitting manner into at least individual annular grooves.

Due to the design of the connecting elements as spring rings, a symmetrical and torque-free force is introduced into the guide vanes. The fact that a single bearing bush is provided for each journal, their production is simplified and component and mounting tolerances of the vane ring can be compensated.

The annular grooves preferably have a conical groove wall and a groove wall pointing in the direction of the inner blade plate, wherein the connecting elements are provided with a conical bearing surface which is substantially complementary to the conical groove wall and with a contact surface which is complementary to the groove wall. Preferably, the groove walls are connected to each other via a rounding, so that notch stresses in the region of the annular grooves are prevented or greatly reduced.

The bushings may each have a radially expanded collar, with which they rest against a radially inner shoulder surface of the openings. By means of the collar, an installation position of the bearing bushes in the openings can be precisely defined.

To create a large-area and flat sliding surface for the inner blade plates may be arranged between these and the bushings each have a washer which rests against a radially outer shoulder surface remote from the radially inner shoulder surface of the bearing bores.

Preferred washers and / or bushings are made of a metallic material or a metallic alloy and their guide or sliding surfaces are provided with a lubricant or lubricant. Due to the metal material, the washers and / or bushings are resistant to abrasion and thus low maintenance. By the lubricant, the guide or storage is friction, so that the blades are adjusted accordingly smoothly. A preferred lubricant is graphite or graphite-based. Alternatively, the washers and / or bushings may consist of a temperature-resistant, mechanically highly resilient and chemically resistant plastic.

A turbomachine according to the invention has at least one guide vane ring according to the invention. Due to optimally set flag columns, such a turbomachine a higher efficiency and a higher surge limit than a turbomachine with a conventional vane ring on.

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

Figur 1

einen Querschnitt durch einen Abschnitt eines erfindungsgemäßen Leitschaufelkranzes,

Figur 2

einen Schnitt durch den Leitschaufelkranz entlang der Linie A-A in Figur 1,

Figur 3

eine Detaildarstellung aus Figur 2,

Figur 4

eine dreidimensionale Darstellung eines bevorzugten Verbindungselement,

Figur 5

eine zweidimensionale Darstellung des Verbindungselement aus Figur 4, und

Figur 6

einen Schnitt durch das Verbindungselement entlang der Linie B-B in Figur 5.

In the following, a preferred embodiment of the invention is explained in more detail with reference to greatly simplified schematic illustrations. Show it:

FIG. 1

a cross section through a portion of a guide vane ring according to the invention,

FIG. 2

a section through the vane ring along the line AA in FIG. 1 .

FIG. 3

a detailed view FIG. 2 .

FIG. 4

a three-dimensional representation of a preferred connecting element,

FIG. 5

a two-dimensional representation of the connecting element FIG. 4 , and

FIG. 6

a section through the connecting element along the line BB in FIG. 5 ,

As shown in FIG. 1 an inventive vane ring 1 a turbomachine such as an aircraft engine, a plurality of vanes 2, an inner ring 4, a seal carrier 6, a plurality of bearing bushes 8, a plurality of fasteners 10 and a plurality of washers 12. The vane ring 1 is the stator side in the compressor Turbomachine arranged and surrounds a rotor portion, not shown, of a rotor which extends around a flow direction x of a main flow and in FIG. 2 sketched machine axis M rotates.

The vanes 2 are adjustable about their main axis H extending radially to the machine axis M and each have an airfoil 14, an inner blade plate 16 and a In addition, the vanes 2 each have an outer blade plate, not shown, and a radially outwardly extending from the outer blade plate adjusting pin, which cooperates with a housing-side adjusting device.

The inner blade plates 16 are, as in FIG. 2 to recognize and for the sake of clarity in FIG. 3 numbered, each arranged in a radial outer countersunk portion 20 of the inner ring 4 radially passing through bearing bore 22. They have a radially inner side and an underside 24 extending along a machine axis M and an upper side 26 opposite the underside 24. The upper side 26 is arranged obliquely to the machine axis M, wherein it extends radially from inside to outside in the flow direction x. It forms with a penetrated by the bearing bore 22 inner ring surface 28 a stepless or nearly stepless radially inner side wall portion of a flowed through by the main flow in FIG. 1 shown annulus 30.

Like also in FIG. 2 to recognize and for the sake of clarity in the detailed representation after FIG. 3 numbered, the bearing pins 18 each have an annular groove 32 for receiving one of the connecting elements 10 in a section remote from the inner blade plates 16. In this way, the bearing pins 18 have a plate-like end portion 34. Preferably, the annular grooves 32 each have a radially tapered from the inner paddles 16 and thus tapered groove wall 36 and the inner blade plates 16 facing and extending transversely to the main axis H groove wall 38th Die Groove walls 36, 38 are each connected to each other via an unnumbered groove base, which is rounded to avoid stress concentrations.

The inner ring 4 serves for the radially inner stabilization or support of the guide vanes 2. It has the bearing bores 22 and the inner ring surface 28 and is spaced from the rotor section via a radial gap. It consists of two half rings each having an arc section of 180 °, which are assembled in the region of a horizontal housing separating plane of the turbomachine to the inner ring 4. Of course, a stronger segmentation of the inner ring 4, for example in four ring segments possible.

The bearing bores 22 pass through the inner ring 4 in the radial direction. They have a sleeve portion 40 with a constant inner diameter, the countersunk portion 20 and an end portion 42. The sleeve portion 40 is disposed between the countersunk portion 20 and the end portion 42 and has a constant inner diameter. The countersunk portion 20 is disposed radially outward of the bushing portion 40. It is radially widened in relation to the bushing section 40 and has thereby and an outer shoulder surface 44. The end section 42 is arranged radially inwards to the bushing section 40. It is radially widened in relation to the bushing section 40 and, as a result, likewise has an inner shoulder surface 46. The shoulder surfaces 44, 46 are oriented opposite to one another or facing away from one another and are of annular design. Preferably, they have a same constant inner diameter.

As in FIG. 2 numbered, the inner ring surface 28 extends downstream of the bearing bores 22 via a rear and obliquely to the machine axis x radially from inside to outside salient axial projection 48 of the inner ring 4. Between the axial projection 48 and the blades 14 is formed in each case a radial so-called flag gap 50, the Achieving a high efficiency of the turbomachine and a high surge limit is minimized.

For receiving the seal carrier 6, the inner ring 4 has a front end-side annular recess 52 and a rear axial annular projection 54, which is arranged radially inwardly of the inner annular surface 28.

The seal carrier 6 is used for positioning of inlet linings 56, 58 for sealing the radial gap between the rotor and the inner ring 4. It is, as in FIG FIG. 2 shown radially inwardly disposed on the inner ring 4. Analogously to the inner ring 4, it preferably has two semicircular carrier segments, which are pushed in the circumferential direction onto the respective half-ring. A carrier segment each consists of a base body 59, on the inner peripheral surfaces of which Einlaufbeläge56, 58 are mounted for engagement of rotor-side sealing webs or sealing fins. The inlet linings 56, 58 are honeycomb seals, for example.

For fixing the seal carrier 6 on the inner ring 4, the base body 59 each have a front hook projection 60 and a rear annular recess 62. With the front hook projection 60 of the seal carrier 6 dips into the front annular recess 62 of the inner ring 4 on. The rear annular recess 62 serves to guide on the rear annular projection 54 of the inner ring 4. In the mounted state, the seal carrier 6 completely covers the inner ring 4 on the inner peripheral side, so that a connecting element 10, for example accidentally broken and fallen from the bearing journal 18, does not penetrate into the annular space 30 and thus not sucked into the turbomachine.

The bushings 8 are, as in FIG. 3 clearly visible, used in the bearing bores 22. They have a T-shaped cross section, each having a guide portion 64 and a relative to the guide portion 64 radially enlarged collar 66. The bearing bushes 8 are with their guide portion 64th arranged in the sleeve portions 40 of the bearing bores 22 and lie with its collar 66 on the radially inner shoulder surface 46 at. Preferably, the guide portions 64 have a same or nearly the same axial length as the bushing portions 40 of the bearing bores 22, so that the bearing bushes 8 do not project beyond the outer shoulder surface 44 with their sleeve portion side annular end surface 68 remote from the collar 66.

The bearing bushes 8 consist in particular of a metallic material or a metal alloy and are coated for friction-free guidance of the bearing pins 18 on their inner peripheral side and fully closed guide surface 70 with a lubricating agent such as graphite.

The connecting elements 10 are, as in the FIGS. 4, 5 and 6 shown, each designed as a spring ring or snap ring and thus self-fixing. They each have a circular opening 72 and are for assembly and disassembly in the respective annular groove 32 along a in FIG. 5 shown dividing plane 74 slotted. The connecting elements 10 engage in a form-fitting manner in the annular grooves 32 and for this purpose have a conical or funnel-shaped contact surface 76 and a contact surface 78 extending transversely to the separating plane 74 opposite the conical contact surface 76. The surfaces 76, 78 are complementary or substantially complementary formed to the groove walls 36, 38. As in FIG. 6 shown, the conical bearing surface 76 may be rounded.

The connecting elements 10 have a constant thickness and an outer diameter which corresponds approximately to the inner diameter of the bearing bush 8. They have a thickness such that they press the collars 66 against the shoulder surface 46 of the respective end portion 42, so that they are respectively clamped between the shoulder surface 46 and the plate-like end portion 34.

To open the connecting elements 10 by means of a tool, for example. A spreading pliers, these each have a lying on the parting plane 74 bore-like tool engagement 80 for attaching the tool. Optionally, the connecting elements 10 on both sides of the parting plane 74 viewed from the tool engagement 80 have two oppositely oriented concave outer peripheral sections 82, 84.

Preferably, the connecting elements 10 each consist of a metallic material or a metal alloy.

The shims 12 have, as in FIG. 3 shown, a bore 86 and a constant thickness. They are thus annular and have an inner diameter which is slightly larger than the outer diameter of the bearing journal 18. Their outer diameter is equal to the diameter of the outer shoulder surface 44. They each have a flat support surface 88 and a sliding surface 90 opposite to this. They are arranged individually in the countersunk sections 20 of the bearing bores 22. They are in each case with their support surface 88 on the outer shoulder surface 44 and extend based on the main axis H radially over the annular end face 68 of the bushings 18. They are thus arranged between the bushings 18 and the inner paddles 16, on the sliding surfaces 90th are guided.

Preferably, the sliding discs 12 each consist of a metallic material or a metal alloy and their sliding surfaces 90 are coated with a lubricant such as graphite.

In the following, a preferred method for mounting the vane ring 1 is explained: The vane ring 1 is thereby mounted per housing half and closed only by the assembly of the two housing halves into a ring. First, the guide vanes 2 used by means of their adjusting pin in corresponding housing-side bearings of the housing halves. The vanes 2 are now oriented like a spoke to each other. Then, the washers 12 are pushed onto the trunnions 18 with their sliding surfaces 90 facing the bottoms 24 of the inner paddles 16. Thereafter, the inner ring 4 or the respective half-ring of the inner ring 4 is positioned on the bearing pin 18. For this purpose, the half rings are arranged with their bearing bores 22 on the bearing pin 18. The half rings are virtually rolled over the bearing pin 18. Then, the connecting elements 10 are inserted into the annular grooves 32. The connecting elements 10 are added self-fixing due to their spring action in the annular grooves 32 and engage around the bearing pin 18 in full. They are clamped with their contact and contact surfaces 76, 78 between the Nutwandungen 36, 38. The guide vanes 2 are now arranged rotatably about their main axis H in the bearing bores 22 and coupled in the radial direction of the vane ring 1 mechanically with the half-rings. Finally, the carrier segments of the seal carrier 6 are pushed onto one of the half rings in the circumferential direction.

Since the bearing pins 18 are fully encompassed by the connecting elements 10, a symmetrical and torque-free force is introduced into the guide vanes 2. In addition, the flag gaps 50 between the axial projection 48 and the blades 14 can be reduced by the mechanical coupling in the radial direction of the vane ring 1, which an improvement in efficiency and an increase in the surge line over conventional turbomachinery leads.

As in FIG. 1 As shown, only some of the blades 2 may be mechanically coupled to the inner ring 4. That is, the connecting elements 10 are not provided on all the guide vanes 2, but are positioned at regular intervals only on a few vanes 2. The guide vanes 2 ', on which the connecting elements 10 are not provided, are preferably formed without a corresponding annular groove 32 and thus have a bearing pin 18', which is axially shortened about the plate-like end portion 34.

Disclosed is a vane ring for a turbomachine whose rotatable vanes are mechanically coupled by means of a spring ring to an inner ring in the radial direction of the vane ring, each guide vane is associated with a bearing bush and the Bearings have a circumferentially closed inner peripheral side guide surface, as well as a turbomachine.

LIST OF REFERENCE NUMBERS

1

vane ring

2, 2 '

vanes

4

inner ring

6

seal carrier

8th

bushings

10

connecting element

12

washer

14

airfoil

16

inner shovel plate

18, 18 '

pivot

20

lowering section

22

bearing bore

24

bottom

26

top

28

Inner ring surface

30

annulus

32

ring groove

34

end

36

tapered groove wall

38

groove wall

40

bushing section

42

end

44

outer shoulder surface

46

inner shoulder surface

48

axial projection

50

flags gap

52

front ring recess

54

rear ring projection

56

inlet lining

58

run-in coating

59

body

60

front hook projection

62

rear ring recess

64

guide section

66

collar

68

Annular face

70

guide surface

72

opening

74

parting plane

76

contact surface

78

contact area

80

drilling

82

concave outer peripheral portion

84

concave outer peripheral portion

86

drilling

88

support surface

90

sliding surface

H

main axis

x

flow direction

z

radial direction

Claims (6)

A vane ring (1) for a turbomachine, comprising a plurality of rotatable vanes (2) each having an inner paddle (16) and a journal (18) extending radially inwardly from the inner paddle (16) and in which an annular groove (32) is introduced in each case in a section remote from the inner blade plate (16), an inner ring (4) for the radially inner stabilization of the guide vanes (2), which has a plurality of radial bearing bores (22), and with a plurality of Bearing bushes (8), wherein the bearing bushes (8) arranged in the bearing bores (28) and the bearing pins (18) in the bearing bushes (8) are guided, and with connecting elements (10) for releasably fixing at least individual guide vanes (2) on the Inner ring (4) in the radial direction of the vane ring (1), characterized in that the bearing bushes (8) between the inner blade plates (16) and the annular grooves (32) are arranged, and that the Ver Binding elements (10) spring rings are that are positively inserted into at least individual annular grooves (32). Guide vane ring according to claim 1, wherein the annular grooves (32) have a conical groove wall (36) and a groove wall (38) facing towards the inner blade plate (16), and wherein the connecting elements (10) are provided with a substantially tapered groove wall (FIG. 36) complementary conical bearing surface (76) and with an axial groove wall (38) complementary contact surface (78) are provided. Guide vane ring according to claim 1 or 2, wherein the bearing bushes (8) each have a radially expanded collar (66), with which they rest against a radially inner shoulder surface (46) of the bearing bores (22). Guide vane ring according to claim 1, 2 or 3, wherein between the inner blade plates (16) and the bearing bushes (8) in each case a sliding disc (12) is arranged, which at one of the radially inner shoulder surface (46) facing away from the radially outer shoulder surface (44) the bearing bores (22) is applied. Guide vane ring according to one of the preceding claims, wherein the bearing bushes (8) and / or the washers (12) metallic and their guide surfaces (70, 90) with a Lubricants are provided. Turbomachine with at least one vane ring (1) according to one of the preceding claims.

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