Blade row poisitioning device, blade-device combination, method and turbomachine

Abstract

A device such as a drum for positioning at least one guide blade row from a plurality of guide blade groups in a turbomachine, the device on the outer circumferential side including at least one flange for attachment to a housing section of the turbomachine and on the inner circumferential side including a plurality of uniformly distributed receptacles for accommodating holding elements of the guide blade groups and a plurality of recesses, the device having a depth-reduced inner circumferential section, relative to the accommodating grooves, between at least two adjoining receptacles, which extends in each case from the one receptacle to the other receptacle; a blade-device combination; a method for assembling such a blade-device combination; and a turbomachine.

Claims

1. A device for positioning one or more guide blade rows in a turbomachine in a circumferential direction, each of the one or more guide blade rows including guide blade groups, each guide blade group including at least two guide blades and at least two holding elements spaced apart from each other in the circumferential direction for connection to the device, the device comprising: at least one flange on an outer circumferential side for attachment to a housing section of the turbomachine and on an inner circumferential side having a plurality of uniformly distributed receptacles for accommodating the holding elements of a guide blade group of a guide blade row of the one or more guide blade rows and a plurality of recesses, each receptacle including a groove that extends in an axial direction, and at least one depth-reduced inner circumferential section, relative to the receptacles, between at least two adjoining receptacles of the guide blade row, and extending directly from one of the two adjoining receptacles to the other adjoining receptacle.

2. The device as recited in claim 1 wherein the device is a drum for accommodating multiple guide blade rows successively.

3. The device as recited in claim 1 wherein the at least one depth-reduced inner circumference section comprises a plurality of depth-reduced inner circumference sections situated in the circumferential direction alternatingly with the recesses.

4. The device as recited in claim 1 wherein the at least one depth-reduced inner circumference section comprises a plurality of depth-reduced inner circumference sections, and wherein the receptacles, recesses and depth-reduced inner circumference sections are offset in the axial direction and are formed for situating multiple guide blade rows successively.

5. The device as recited in claim 1 wherein the at least one depth-reduced inner circumference section comprises a plurality of depth-reduced inner circumference sections, and wherein the depth-reduced inner circumference sections offset from each other in the axial direction have a similar circumferential position.

6. The device as recited in claim 1 wherein the at least one depth-reduced inner circumference section has a depth=0 relative to an inside radius of the device from which the receptacles extend radially outwardly.

7. A blade-device combination of a turbomachine, comprising the device as recited in claim 1.

8. The blade-device combination as recited in claim 7 wherein the at least one depth-reduced inner circumference section comprises one or more depth-reduced inner circumference sections, and wherein a number of depth-reduced inner circumference sections is smaller than or equal to the number of guide blade groups.

9. A method for assembling a blade-device combination of a turbomachine, including the following steps: providing a device as recited in claim 1; providing the guide blade groups; and inserting the guide blade groups into the device, the guide blade group inserted first being aligned via the at least one depth-reduced inner circumference section.

10. A turbomachine including a blade-device combination as recited in claim 7.

11. The device as recited in claim 1, wherein each holding element comprises an axial rib receivable in the grooves.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Preferred exemplary embodiments of the present invention are described in greater detail hereafter based on schematic illustrations.

(2) FIG. 1 shows an upstream view of a device according to the present invention;

(3) FIG. 2 shows a detailed illustration of the device from FIG. 1;

(4) FIG. 3 shows a setpoint positioning of a guide blade group in the device; and

(5) FIG. 4 shows a prevented malpositioning of a guide blade group in the device.

DETAILED DESCRIPTION

(6) FIG. 1 shows a rear view of a device 1 for positioning at least one guide blade row in a turbomachine. Rear means that the view of the observer is directed upstream or against the flow direction of a hot gas flowing through the turbomachine. The turbomachine is an aircraft engine, for example, and in particular a gas turbine. Device 1 has a thin-walled, drum-shaped body or a drum 2 which, viewed in the flow direction, is radially or conically widened relative to an axial machine axis m. FIG. 1 thus shows a view into device 1 onto its inner circumference, device 1 radially or conically tapering in the viewing direction. Device 1 is preferably situated in the low-pressure turbine of the turbomachine.

(7) Device 1 is used in a housing section of the turbomachine and for this purpose has a flange ring 4 on the outer circumference side of its drum-shaped body 2, the flange ring having a plurality of attachment ears in each of which an axial bore 6 for leading through a respective attachment screw is formed. In the exemplary embodiment shown here, device 1 is used to accommodate four guide blade rows situated successively in the flow direction. For the sake of clarity, hereafter only three guide blade rows are considered. However, the fourth guide blade row not considered is designed analogously to the three considered guide blade rows.

(8) Due to the radial widening of device 1 in the flow direction relative to a central annular land 10 for accommodating a central guide blade row, a front annular land 8 for accommodating a front guide blade row is situated radially on the inside and a rear annular land 12 for accommodating a rear guide blade row is situated radially on the outside. Annular lands 8, 10, 12 and the guide blade rows are thus situated on different inside radii r.sub.i, r.sub.m, r.sub.a.

(9) As is shown in FIG. 2, each annular land, i.e. support ring, 8, 10, 12 has a plurality of uniformly distributed accommodating grooves 14, 16 for fixing the particular guide blade row. Accommodating grooves 14, 16 extend in the axial direction through the particular annular land 8, 10, 12 and are thus open axially and radially on the inside on both sides. In the exemplary embodiment shown here, they have a rectangular cross section having a constant depth t or a radial extension. Depth t is ablated in each case from an annular land inner circumferential surface, which is assigned the particular inside radii r.sub.i, r.sub.m, r.sub.a.

(10) To reduce the weight and/or adjust structural mechanical properties of device 1, at least one recess 18 may be provided between two adjoining accommodating grooves 14, 16, as is illustrated on front annular land 8 and central annular land 10. In the exemplary embodiment shown here, front annular land 8 has a recess 18 and a profile-free section 20 in each case between multiple adjoining accommodating grooves 14, 16. In contrast, central annular land 10 in the exemplary embodiment shown here has two recesses 18, 22 between multiple adjoining accommodating grooves 14, 16, the two recesses being spaced apart from each other via a profile-free or non-contoured section 20. To avoid tension peaks, recesses 18, 22 are concave in the exemplary embodiment shown here, and are thus designed as archings or tub-like contours. Preferably they have a depth which is equal to or even greater than the depth of accommodating grooves 14, 16.

(11) Each annular land 8, 10, 12 includes at least one depth-reduced inner circumference section 24, relative to two adjoining accommodating grooves 14, 16, which extends in each case from one accommodating groove 14 to the other accommodating groove 16. Depth-reduced inner circumference sections 24 of annular lands 8, 10, 12 are almost situated at the same circumferential position and, relative to the particular annular land inner circumferential surface from which accommodating grooves 14, 16 extend radially outwardly, have a depth equal to zero, so that depth-reduced inner circumference sections 24 in the exemplary embodiment shown here are recess-free or trace an original contour of the annular land inner circumferential surface. In the exemplary embodiment shown here, depth-reduced inner circumferential sections 24 thus have a concave surface 26, which is identical to the annular land inner circumferential surface interrupted by accommodating grooves 14, 16 and recesses 18, 22.

(12) As is indicated in FIG. 3 on central annular land 10, each guide blade row includes a plurality of guide blade groups 28, which in turn are composed of a plurality of guide blades 30, 32, 34. In the exemplary embodiment shown here, guide blade group 28 includes three guide blades 30, 32, 34, which in each case are provided with a radially outer holding element 36, 38, 40 for engaging in one of accommodating grooves 14, 16, 42. Of course, only two holding elements 36, 38, 40 are also possible. Holding elements 36, 38, 40 are spaced apart from each other in the circumferential direction and are axial ribs, for example, which cooperate with accommodating grooves 14, 16, 42 in a form-locked manner.

(13) In a method according to the present invention for assembling the blade-device combination indicated in FIG. 3, device 1 is provided first. Then, guide blade groups 28 of the particular guide blade row are provided. Thereafter, guide blade groups 28 are inserted with their holding elements 36, 38, 40 into accommodating grooves 14, 16, 42 of device 1, the guide blade group inserted first being aligned on at least one depth-reduced inner circumference section 24. When at least one of holding elements 36, 38, 40 runs against depth-reduced inner circumference section 24, guide blade group 28 is offset in the circumferential direction and thereby transferred into its setpoint, i.e. desired, position. Thereafter, the next guide blade group is inserted into device 1, the group being aligned on preceding guide blade group 28 and malpositioning being thereby prevented. This is repeated until all guide blade groups 28 of the guide blade row are inserted.

(14) As is shown in FIG. 4, guide blade group 28 is not assembleable since depth-reduced inner circumference section 24 is flatter than accommodating grooves 14, 16, 42. Insertion of guide blade group 28 is prevented by, here left, holding element 36 running against depth-reduced inner circumference section 24. The holding element running against the section thus indicates to an assembler that guide blade group 28 is not in its setpoint position, but in a faulty position on the circumferential side, in which central holding element 38 and right holding element 40 immerse into recesses 18, 44 instead of engaging in accommodating grooves 16, 42. As a result, the assembler offsets guide blade group 28 in the circumferential direction until it is displaceable in the axial direction relative to device 1. According to the illustration of FIG. 3, guide blade group 28 is offset to the left. Guide blade group 28 now engages with its holding elements 36, 38, 40 in each case in one of accommodating grooves 14, 16, 42 and is situated in its setpoint position. Depth-reduced inner circumference section 24 situated between accommodating grooves 14, 16 now does not hinder the assembly since guide blade group 28 is in its setpoint position.

(15) Disclosed is a device such as a drum for positioning at least one guide blade row from a plurality of guide blade groups in a turbomachine, the device on the outer circumferential side including at least one flange for attachment to a housing section of the turbomachine and on the inner circumferential side including a plurality of uniformly distributed receptacles for accommodating holding elements of the guide blade groups and a plurality of recesses, the device having a depth-reduced inner circumferential section, relative to the accommodating grooves, between at least two adjoining receptacles, which extends in each case from the one receptacle to the other receptacle; a blade-device combination; a method for assembling such a blade-device combination; and a turbomachine.

LIST OF REFERENCE NUMERALS

(16) 1 device/drum 2 body 4 flange ring 6 axial bore 8 annular land 10 annular land 12 annular land 14 accommodating groove 16 accommodating groove 18 recess 20 profile-free section 16 recess 22 recess 24 depth-reduced inner circumference section 26 surface 28 guide blade group 30 guide blade 32 guide blade 34 guide blade 36 holding element/rib 38 holding element/rib 40 holding element/rib 42 accommodating groove 44 recess m machine axis r.sub.i inside radius of front annular land r.sub.m inside radius of central annular land r.sub.a inside radius of rear annular land t depth