Rotor blade arrangement having elastic support elements for a thermal turbomachine

Abstract

A rotor blade arrangement for a turbomachine having a blade carrier, on whose outer circumferential surface there is formed a circumferential T-shaped slot, having a blade ring which has a plurality of blades and spacers, that are inserted in alternation into the T-shaped slot, and having support elements that are braced between the blades and spacers on one hand and a base of the T-shaped slot on the other hand such that the blades and spacers are pressed radially outward, a separate support element being assigned to each spacer and being releasably held thereon, in particular secured in a clamping manner. A method includes assembling a rotor blade arrangement.

Claims

1. A rotor blade arrangement for a turbomachine, comprising: a blade carrier on whose outer circumferential surface there is formed a circumferential T-shaped slot, a blade ring which comprises a plurality of blades and spacers that are inserted in alternation into the T-shaped slot along the circumference of the T-shaped slot, and having support elements that are braced between the blades and spacers on the one hand and a bottom of the T-shaped slot on the other hand such that the blades and spacers are pressed radially outward, and a separate support element which is assigned to each spacer and is releasably held thereon.

2. The rotor blade arrangement as claimed in claim 1, wherein the support elements are designed as elastic spring plates and arranged such that the associated spacers in the T-shaped slot are preloaded radially outward.

3. The rotor blade arrangement as claimed in claim 1, wherein at least one radially outward projecting projection is formed on each of the support elements, which projection comes into engagement with the respective associated spacer in order to secure the support elements on the associated spacers.

4. The rotor blade arrangement as claimed in claim 3, wherein cutouts corresponding to the projections are formed in the spacers, into which cutouts the projections of the support elements engage in a clamping manner.

5. The rotor blade arrangement as claimed in claim 4, wherein the cutouts are arranged axially centrally on the spacers, wherein they have an axial breadth that corresponds to at least 30% of the axial breadth of the spacers.

6. The rotor blade arrangement as claimed in claim 5, wherein the cutouts are arranged axially centrally on the spacers and have an axial breadth that corresponds to at least 50% of the axial breadth of the spacers.

7. The rotor blade arrangement as claimed in claim 5, wherein the axial breadth of the projections of the support elements corresponds at least substantially to the axial breadth of the cutouts.

8. The rotor blade arrangement as claimed in claim 4, wherein on each of the support elements there are formed two projections that are spaced apart in the circumferential direction of the T-shaped slot.

9. The rotor blade arrangement as claimed in claim 8, wherein the two projections are in each case arranged on the support elements such that the associated spacers are clamped between the projections.

10. The rotor blade arrangement as claimed in claim 8, wherein the relevant projections of the support elements are configured such that, when bearing against the respective immediately adjacent blade, they exert a force acting in the circumferential direction.

11. The rotor blade arrangement as claimed in claim 10, wherein the relevant projections are in each case essentially U-shaped and have two elastic limbs which are connected to one another and of which one limb bears against the spacer and the other limb bears against the relevant adjacent blade.

12. The rotor blade arrangement as claimed in claim 8, wherein the two corresponding cutouts are formed on end faces of the spacer that are opposite in the circumferential direction of the T-shaped slot.

13. The rotor blade arrangement as claimed in claim 8, wherein the projections of the support elements are received in the corresponding cutouts of the associated spacers such that the end faces of the spacers come to bear against adjacent blades.

14. The rotor blade arrangement as claimed in claim 8, wherein a wave-shaped spring region is formed in each case between the projections such that the spring region, adjacent to the projections, comes to bear against the bottom of the T-shaped slot, and a central region comes to bear against the associated spacer.

15. The rotor blade arrangement as claimed in claim 1, wherein the support elements are arranged spaced apart from one another in the circumferential direction of the T-shaped slot, and/or each one of the blades in question is pressed radially outward by two adjacent intermediate pieces.

16. The rotor blade arrangement as claimed in claim 1, wherein end regions, opposite one another in the circumferential direction of the T-shaped slot, of the support elements project from the associated spacers such that they engage under adjacent blades.

17. The rotor blade arrangement as claimed in claim 16, wherein each projecting end region is designed such that it preloads the adjacent blade radially outward, and in so doing comes to bear against the adjacent blade and the bottom of the T-shaped slot.

18. The rotor blade arrangement as claimed in claim 17, wherein at least one bead is formed on each end region, which bead comes to bear against the bottom of the T-shaped slot and is positioned in an axially central region of the end region.

19. The rotor blade arrangement as claimed in claim 1, wherein the separate support element is releasably held thereon in a clamping manner.

20. A method for assembling a rotor blade arrangement as claimed in claim 16, comprising the following steps: inserting a blade into the T-shaped slot and shifting the blade in the circumferential direction of the T-shaped slot to its intended position; arranging a support element on a spacer such that the support element is releasably held on the spacer, in a clamping manner; inserting the spacer, with the support element arranged thereon, into the T-shaped slot and shifting the spacer in the circumferential direction of the T-shaped slot such that an end face of the spacer comes to bear against the blade inserted into the T-shaped slot and an end region of the support element engages under the inserted blade; inserting a further blade into the T-shaped slot and shifting the further blade in the circumferential direction of the T-shaped slot such that the further blade comes to bear against the opposite end face of the inserted spacer and the opposite end region of the support element engages under the further blade.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features and advantages of the present invention will become clear from the following description of an embodiment of the rotor blade arrangement according to the invention, with reference to the appended drawing, in which:

(2) FIG. 1 is a cross-sectional view of a portion of a rotor blade arrangement according to one embodiment of the present invention;

(3) FIG. 2 is a perspective view from below of a support element, of the rotor blade arrangement shown in FIG. 1, that is held on a spacer;

(4) FIG. 3 is a side view of the spacer shown in FIG. 2; and

(5) FIG. 4 is a cross-sectional view, along the line IV-IV, of the spacer shown in FIG. 3.

DETAILED DESCRIPTION OF INVENTION

(6) FIGS. 1 to 4 show a rotor blade arrangement 1 for a turbomachine according to one embodiment of the present invention. The rotor blade arrangement 1 comprises a blade carrier 2 on whose outer circumferential surface 3 there is formed a circumferential T-shaped slot 4, and a blade ring 5. The blade ring 5 has a plurality of blades 6 and spacers 8, wherein blade roots 7 of the blades 6 are inserted, in alternation with the spacers 8, into the T-shaped slot 4.

(7) Furthermore, the rotor blade arrangement 1 comprises support elements 9 that are braced between the respective undersides 6a of the blades 6 and the respective undersides 8a of the spacers 8 on the one hand and a bottom 10 of the T-shaped slot 4 on the other hand such that the blades 6 and the spacers 8 are pressed radially outward against shoulder faces of the T-shaped slot. The support elements 9 are designed as elastic spring plates and are arranged spaced apart from one another in the circumferential direction of the T-shaped slot 4. In that context, a separate support element 9, which is releasably fixed, is assigned to each spacer 8.

(8) To that end, two radially outward projecting projections 11 are formed on each of the support elements 9 in the present case. The projections 11 can be designed as portions of the elastic spring plate that are U-shaped in cross section and comprise two limbs 17, 18 that are connected to one another. The projections 11 engage with the respective associated spacer 8 in order to securely clamp the support elements 9 against the associated spacers 8.

(9) Specifically, the spacers 8 have cutouts which correspond to the projections 11 of the associated support elements 9 and which are designed as open depressions in the circumferential-side end faces of the spacers 8. In that context, the depth of the cutouts in the circumferential direction is such that the projections 11 are fully accommodated in the cutouts 12, and the spacer 8 is securely clamped between the projections 11. In that context, the cutouts 12 are arranged axially centrally on the spacers 8, and have an axial breadth that corresponds to approximately 50% of the axial breadth of the spacers 8. Furthermore, the projections 11 of the support elements 9 have an axial breadth that corresponds to the axial breadth of the cutouts 12, so as to ensure that the support elements 9 are positioned and engage approximately axially centrally on the spacers 8.

(10) Advantageously, the two projections 11 of each support element 9, as seen in the circumferential direction, can be configured such that they project slightly from the cutouts 12. Consequently, the inner end of the intermediate piece 8 in question is then resiliently clamped between the two first limbs 17 of the two projections 11, wherein the two other limbs 18 extend outward via those side faces of the intermediate pieces that are oriented toward the adjacent blades 6. Owing to the arcuate connection region between the two limbs 17, 18 of each projection 11, the limbs 17, 18 thereof are able to move elastically with respect to one another. In the assembled state, the limbs 18 bear, preloaded, against the sidewalls of the blades 6 so that the circumferential bracing produced thereby ensures a clearance-free fit of the intermediate pieces 8 and the blades 6.

(11) Alternatively, a support element 9 can also be secured to a spacer 8 by means of a single projection 11 and a single corresponding cutout 12.

(12) A wave-shaped spring region 13 is formed between the two projections 11 and has in each case, adjacent to the two projections 11, wave troughs 13a that come to bear against the bottom 10 of the T-shaped slot 4 and, between the wave troughs 13a, a wave peak 13b that comes to bear against the associated spacer 8.

(13) The support elements 9 also have, opposite one another in the circumferential direction of the T-shaped slot 4, end regions 14 which in the present case are tongue-shaped and which project from the associated spacers 8 in the circumferential direction of the T-shaped slot 4 such that they engage under adjacent blades 6. Each projecting end region is designed such that it preloads the adjacent blade 6 radially outward and presses it against shoulder faces of the T-shaped slot 4, wherein it comes to bear against the adjacent blade 6 and the bottom 10 of the T-shaped slot 4. In that context, a bead 15, which is formed at each projecting end region 14 and projects radially inward from the end region 14, comes to bear against the bottom 10 of the T-shaped slot 4 while the free end of the projecting end region bears against the adjacent blade 6. The bead 15 is positioned in an axially central region of the end region 14 and has an axial breadth that corresponds to approximately 50% of the axial breadth of the end region 14.

(14) In order to assemble a rotor blade arrangement according to the invention, a blade 6 is first inserted into the T-shaped slot 4 and is shifted in the circumferential direction of the T-shaped slot 4 to its intended position. Then a support element 9 is clamped on a spacer 8. In that regard, the support element 9 is fitted onto the spacer 8 from below so that the two projections 11 of the support element 9 come into clamping engagement with the corresponding cutouts 12 of the spacer 8. Then, the spacer 8, with the support element 9 arranged thereon, is inserted into the T-shaped slot 4 and is shifted in the circumferential direction of the T-shaped slot 4 such that an end face of the spacer 8 comes to bear against the blade 6 inserted into the T-shaped slot 4 and an end region 14 of the support element 9 engages under the inserted blade 6. In the case of the above-described support element 9, the spacer 8 inserted into the T-shaped slot 4 is preloaded radially outward by the elastic spring force of the spring region 13. Therefore, for shifting, a radially inward oriented force is exerted on the spacer 8 counter to its outward-oriented elastic return force. Then, a further blade 6 is inserted into the T-shaped slot 4 and is shifted in the circumferential direction of the T-shaped slot 4 such that the further blade 6 comes to bear against the opposite end face of the spacer 8 and the opposite end region 14 of the support element 9 engages under the further blade 6. Both adjacent blades 6 are pressed, by the beads 15 provided in each case on the under-engaging end region 14, radially outward in the T-shaped slot against shoulder faces of the T-shaped slot 4, and are radially immobilized. These method steps are repeated until the blade ring 5apart from a final gapis closed. Finally, a special closing assembly (not shown) is inserted into the remaining gap in order to close the blade ring 5.

(15) An essential advantage of the rotor blade arrangement 1 according to the invention is that the support elements 9 are easily secured on the spacers 8 outside the T-shaped slot 4, and subsequently are handled only together with the associated spacers 8. Thus, assembling a rotor blade arrangement 1 according to the invention requires no special method steps and/or tools for correctly placing the support elements 9 in the T-shaped slot 4, which implies simple assembly of the blade ring 5.

(16) Although the invention has been described and illustrated in detail by way of the preferred exemplary embodiment, the invention is not restricted by the disclosed examples and other variations can be derived herefrom by a person skilled in the art without departing from the scope of protection of the invention.