Blade root receptacle for receiving a rotor blade

Abstract

Blade root receptacle for receiving a blade root of a rotor blade of a turbomachine. The blade root receptacle, for radially bearing in a form-fitting manner on the blade root, has a supporting flank which, in terms of a rotation axis, at least in proportions faces radially inward, wherein the supporting flank is provided with a convexity which, when viewed in an axially perpendicular section, at least in portions has a convex shape and, also when viewed in an axially parallel section, at least in portions has a convex shape.

Claims

1. A blade root receptacle, wherein the receptacle is suitable for receiving a blade root of a rotor blade of a turbomachine and the blade root receptacle, for radially bearing in a form-fitting manner on the blade root, comprises a supporting flank which in terms of a rotation axis at least in proportions faces radially inward, the supporting flank being provided with two or more convexities which, when viewed in an axially perpendicular section, at least in portions have a convex shape, and also, when viewed in an axially parallel section, at least in portions have a convex shape, at least some of the two or more convexities being separated in axial direction.

2. The blade root receptacle of claim 1, wherein, when viewed in the axially parallel section, the convex shape of the supporting flank transitions to a concave profile toward a first axial end of the supporting flank.

3. The blade root receptacle of claim 2, wherein, when viewed in the axially parallel section, a point at which the supporting flank transitions from the convex shape to the concave profile is spaced apart from the first axial end by at least 5% of an axial length of the supporting flank.

4. The blade root receptacle of claim 3, wherein, when viewed in the axially parallel section, the supporting flank runs in a rectilinear manner into the first end.

5. The blade root receptacle of claim 2, wherein, when viewed in the axially parallel section, the convex shape transitions to a concave profile also toward a second axial end of the supporting flank, opposite the first axial end of the supporting flank.

6. The blade root receptacle of claim 1, wherein, when viewed in the axially perpendicular section, the convex shape transitions to a concave profile.

7. The blade root receptacle of claim 1, wherein a convexity in each section perpendicular to the supporting flank through the convexity has a profile which is free of spikes, jumps and/or edges.

8. The blade root receptacle of claim 1, wherein for at least one of the two or more convexities a ratio of height to smallest transverse dimension of the convexity ranges from 1:2 to 1:500.

9. The blade root receptacle of claim 1, wherein for at least one of the two or more convexities a ratio of height to smallest transverse dimension of the convexity ranges from 1:10 to 1:200.

10. The blade root receptacle of claim 1, wherein for at least one of the two or more convexities a ratio of height to smallest transverse dimension of the convexity ranges from 1:100 to 1:500.

11. The blade root receptacle of claim 1, wherein at least some of the two or more convexities are mutually axially offset.

12. The blade root receptacle of claim 1, wherein at least some of the two or more convexities are mutually offset by a radial component and/or an encircling component.

13. The blade root receptacle of claim 1, wherein three convexities are formed in the supporting flank.

14. A blade assembly, wherein the assembly comprises the blade root receptacle of claim 1 and a rotor blade whose blade root is disposed in the blade root receptacle and bears on the supporting flank.

15. A rotor disk, wherein the rotor disk is suitable for a rotor blade assembly of a turbomachine and comprises a plurality of blade root receptacles according to claim 1.

16. A method for producing the blade root receptacle of claim 1, wherein the method comprises machining the supporting flank of the blade root receptacle in each case by electrochemical machining from a solid material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be explained in more detail hereunder by means of an exemplary embodiment, wherein the individual features in the context of the independent claims may also be relevant to the invention in another combination, and a detailed distinction between the different categories of claims is furthermore also not made.

(2) In the drawings:

(3) FIG. 1 shows a turbomachine, specifically a turbofan engine, in an axial section;

(4) FIG. 2 shows a blade root receptacle in a schematic axial view;

(5) FIG. 3 shows a supporting flank of the blade root receptacle according to FIG. 2 in an axially perpendicular section;

(6) FIG. 4 shows the supporting flank according to FIG. 3 in an axially parallel section; and

(7) FIG. 5 shows a supporting flank of an alternative design in a schematic plan view.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

(8) The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description in combination with the drawings making apparent to those of skill in the art how the several forms of the present invention may be embodied in practice.

(9) FIG. 1 shows a turbomachine 1, specifically a turbofan engine, in an axial section. The turbomachine 1 in functional terms is made up of a compressor 1a, a combustion chamber 1b and a turbine 1c. The compressor 1a as well as the turbine 1c are in each case constructed from a plurality of stages. Each one of the stages is composed of a guide vane assembly and a rotor blade assembly. For the sake of clarity, the guide vane assembly 3 and the associated rotor blade assembly 4 for only one of the stages of the turbine 1c are provided with reference signs. The inducted air is compressed in the compressor 1a and in the downstream combustion chamber 1b is combusted together with added kerosine. The hot gas flows through the hot gas duct and in the process drives the rotor blade assemblies that rotate about the rotation axis 2. The rotor blade assembly 4 comprises a rotor disk 4.1 in which a plurality of rotor blades 4.2 are inserted so as to be distributed in an encircling manner.

(10) FIG. 2 shows a fragment of the rotor disk 4.1 in an axial view, thus in a view onto said rotor disk 2 along the rotation axis 2. A blade root receptacle 20 which is incorporated in the form of a profiled groove that axially penetrates the rotor disk 4.1 is provided in the rotor disk 4.1. A blade root 21 of the respective rotor blade 4.2 is inserted into the blade root receptacle 20, said blade root being only schematically indicated and in terms of the radial direction 22 being held in a form-fitting manner in said blade root receptacle 20. During operation said blade root 21 is pressed against supporting flanks 25 of the blade root receptacle, only one of said supporting flanks 25 being provided with a reference sign and being discussed in more detail here.

(11) The supporting flank 25 extends between a convex curvature portion 26 and a concave curvature portion 27, the breadth 28 of said supporting flank 25 to be seen in the illustration according to FIG. 2. The supporting flank 25 has the longitudinal extent thereof perpendicularly thereto, thus in the axial direction 32. Said supporting flank 25 presently is oriented in such a manner that said supporting flank 25 in proportions runs in the radial direction 22 and also in the encircling direction 33.

(12) FIG. 3 shows the supporting flank 25 in a detailed view, specifically in a section perpendicular to the axial direction 32. Said section allows a convexity 40 of a convex shape 41 to be seen. The convex shape 41 on both sides transitions to a concave profile 42.

(13) FIG. 4 shows the convexity 40 in a section plane perpendicular thereto, specifically in an axially parallel section A-A (cf. FIG. 2 with respect to the position of the section plane). The convexity 40 also has a convex shape 51 in this section, said convex shape 51 in the present example in the direction of a first axial end 61 as well as in the direction of a second axial end 62 transitioning in each case first to a concave profile 52 and thereafter to a rectilinear profile 53. In terms of an axial length 55 of the supporting flank 25, a transition 56 between a convex/concave extent in this example is approximately at a distance of 30% from the first axial end 61 (this laterally reversed also applying to the other transition and the second axial end 62).

(14) FIG. 5 shows a supporting flank 25 in a schematic plan view in which, in addition to the (first) convexity 40, a further convexity 70, which is axially and also in an encircling or radial manner, respectively, offset in relation to the first convexity 40, is provided. A total of three convexities 71, which conjointly form a defined bearing face, are provided in the supporting flank 25.

LIST OF REFERENCE SIGNS

(15) Turbomachine 1 Compressor 1a Combustion chamber 1b Turbine 1c Rotation axis/Longitudinal axis 2 Guide vane assembly 3 Rotor blade assembly 4 Rotor disk 4.1 Plurality of rotor blades 4.2 Blade root receptacle 20 Blade root 21 Radial direction 22 Supporting flanks 25 Convex curvature portion 26 Concave curvature portion 27 Breadth 28 Axial direction 32 Encircling direction 33 First convexity 40 Convex shape 41 Axially parallel section A-A Convex shape 51 Concave profile 52 Rectilinear profile 53 Axial length 55 Transition 56 First axial end 61 Second axial end 62 Further convexity 70 Three convexities 71