ROTOR BLADE FOR WIND TURBINES

Abstract

The invention relates to a segmented rotor blade for wind turbines, the segmented rotor blade having spar elements which can be telescoped into one another. According to the invention, in order to screw the telescoped spar elements together, one of the bushes is designed as a slide bush to achieve a better connection of the segmented rotor blades.

Claims

1. A segmented rotor blade for wind turbines, comprising: at least two blade segments which extend in opposite directions from a junction, wherein each blade segment comprises at least one spar element which forms a structural element of the rotor blade; a spar connector extending from a first spar element of a first blade segment in a direction of a second blade segment and into a connection section of a second spar element of the second blade segment and connecting the first and second blade segments of the at least two blade segments to one another via the first and second spar elements, wherein openings in the spar connector and the second spar element of the second blade segment include one or more bushings for receiving at least one connection bolt, wherein the connection bolt passes through the one or more bushings and connects the spar connector to the second spar element of the second blade segment, wherein at least one of the one or more bushings is a slide bushing which can move axially in the opening in the spar connector and/or the second spar element.

2. The rotor blade as claimed in claim 1, wherein the first and second spar elements each have two opposing web sections which are connected to one another by two opposing flange sections, wherein the flange sections lie in a plane of rotation of the rotor blade, and wherein the openings are provided in the web sections of the first and second spar element.

3. The rotor blade as claimed in claim 1, wherein the second spar element of the second blade segment has, at least in a connection section, a cavity into which the spar connector extends in the assembled state of the at least two blade segments, wherein at least one bushing of the second spar element of the second blade segment is the a slide bushing.

4. The rotor blade as claimed in claim 3, wherein the slide bushing the second spar element of the second blade segment bears with a force fit against the bushing of the spar connector when the spar connector (20) is connected to the second spar element of the second blade segment by the connection bolt.

5. The rotor blade as claimed in claim 1, wherein the spar connector extends into a connection section of the second spar element of the second blade segment.

6. The rotor blade as claimed in claim 1, wherein the spar connector narrows in a direction of an extending connection section.

7. The rotor blade as claimed in claim 1, wherein at least one of the openings has a clamping bushing which has a passage into which another bushing is inserted.

8. The rotor blade as claimed in claim 7, wherein the slide bushing is inserted into the clamping bushing such that, when connecting the at least two blade segments, the slide bushing is held in the clamping bushing so that it can move axially, and such that, once the at least two blade segments are connected by the connection bolt, the slide bushing is seated with a force fit in the clamping bushing.

9. The rotor blade as claimed in claim 1 wherein the slide bushing is held so as to be able to move axially in a flanged bushing inserted the opening in the spar connector and/or the second spar element.

10. The rotor blade as claimed in claim 1 wherein at least one of the bushings has teeth which engage with teeth of a mating bushing.

11. A wind turbine with a multi-blade rotor having at least one rotor blade as claimed in claim 1.

Description

[0033] There follows an exemplary explanation of the invention with reference to the appended figures, in which:

[0034] FIG. 1—is a schematic illustration of the segmented rotor blade;

[0035] FIG. 2—shows a cross section of the screw connection in a first embodiment;

[0036] FIG. 3—shows a cross section of the screw connection in a second embodiment;

[0037] FIG. 4—shows a cross section of the screw connection in a third embodiment;

[0038] FIG. 5—shows a cross section of the screw connection in a fourth embodiment.

[0039] FIG. 1 shows, schematically and in a plan view, the segmented rotor blade 10 which has a first blade segment 11 and a second blade segment 12. Both blade segments 11 and 12 each have a respective spar element, 21 and 22, which together form a structural element of the rotor blade 10. A trailing edge strip 16, which stabilizes the rear portion of the rotor blade 10, can be provided at the trailing edge 13 of the rotor blade 10.

[0040] In that context, the two blade segments 11 and 12 are joined to one another at a junction 14, wherein the spar element 21 of the first blade segment 11 extends beyond the junction 14 in the direction of the second blade segment 12. The spar element 22 of the second blade segment 12 has a cavity 24 into which the spar element 21 of the first blade segment 11 extends. The spar element 21 of the first blade segment 11 extends into the connection region 23 of the second blade segment 12, in which the spar element 21 of the first blade segment 11 is connected to the spar element 22 of the second blade segment 12 by means of a screw connection 30.

[0041] FIGS. 2 to 4 now explain the screw connection 30 of FIG. 1 in the cross section A-A. FIG. 2 shows, in the cross section of the screw connection 30, the inner spar element 21 of the first blade segment 11 which is inserted into the cavity of the outer spar element 22 of the second blade segment 12. Both the inner spar element 21 and the outer spar element 22 are formed of opposing web sections that are connected to one another by flange sections. Thus, the outer spar element 22 has an upper flange section 40a and a lower flange section 40b which connects the two web sections 41a and 41b to one another. The inner spar element 21 is formed in a corresponding manner. In that context, the web section 41a is oriented toward the leading edge 15 while the web section 41b is oriented toward the rotor blade trailing edge 13. The flange sections 40a and 40b lie in the plane of rotation of the rotor blade.

[0042] In the web sections 41a, 41b, 43a, 43b of the spar elements 21, 22, openings are provided in the region of the screw connection, into which openings are inserted, according to the invention, bushings of which at least one is a slide bushing.

[0043] In the exemplary embodiment of FIG. 2, a flanged bushing 50 is first provided in the openings in the web sections 41a, 41b of the spar element 22 (the outer spar element), which flanged bushing 50 is designed to receive the slide bushing 51. In the spar element 21 (the inner spar element) there is provided, in the openings of the web sections 43a, 43b, a through-bushing 52 which is axially aligned with the opening of the slide bushing 51 of the outer spar element 22. This axial alignment now permits the passage of a connection bolt 53 which is for example designed as a screw. On one side, the screw has a screw head 54 and, at the other end, a thread onto which a nut 55 is screwed.

[0044] Owing to the fact that the slide bushing 51 is guided such that it can move axially in the flanged bushing 50, establishing the screw connection with the nut 55 exerts a force in the direction of the inner spar element 21, which presses the slide bushing 51 against the through-bushing 52 of the inner spar element 21. Thus, the outer bushings 51 of the outer spar element are pressed against the inner through-bushing 52, producing a force-fitting connection between the slide bushings 51 and the through-bushing 52 at this point.

[0045] The slide bushings are fixed axially by means of a threaded ring 56 which is screwed onto both slide bushings 51, in order to thus be able to absorb forces in the Y-direction.

[0046] FIG. 3 shows an exemplary embodiment in which only the bushing of that web section 41a of the spar element 22 that is oriented toward the blade leading edge 15 is designed as a slide bushing 51. At the opposite web section 41b, which is oriented toward the blade trailing edge 13, a flanged bushing 57 with an internal thread is introduced into the web section 41b such that it is possible to dispense with the screw head 54 of FIG. 2. Thus, when connecting the two blade segments, the screw 53 is screwed into the flanged bushing 57, wherein tightening the nut 55 then causes a force to act in the direction of the flanged bushing 57, whereby the slide bushing 51 is pressed against the through-bushing 52. Thus, the inner spar element 21 with a through-bushing 52 is also pressed against the flanged bushing 57 with the internal thread, thus ultimately producing a force-fitting connection between the respective bushings.

[0047] In both variants of FIG. 2 and FIG. 3, the fit between the slide bushing and the flanged bushing is a snug clearance fit, e.g. h7/h6, such that a changing impact bending moment gives rise to only a very small movement in the Z-direction. This play can possibly be eliminated entirely by firm tightening of the threaded ring.

[0048] The variant of FIG. 2 has the advantage that the screw connection has more play since all of the bushings have through-bores. Thus, any errors can be better intercepted. Furthermore, assembly is simpler if the connection is accessible and visible from both sides.

[0049] The variant of FIG. 3 has the advantage that the rotor blade shell at the trailing edge is no longer simply interrupted. In particular, the trailing edge strip contained therein experiences relatively high loads which thus do not have to be transmitted multiple times.

[0050] FIG. 4 shows an exemplary embodiment in which the slide bushing 51 and the through-bushing 52 of the inner spar element 21 are guided in a clamping bushing 60, 61. Another particular feature of the exemplary embodiment of FIG. 4 is that the slide bushing 58 has an internal thread at the trailing edge 13, such that the connection bolt or the connection screw 53 can be screwed into this slide bushing with the internal thread 58.

[0051] The provision of clamping bushings 60, 61 has the advantage that the slide bushings 51, and/or the through-bushing 52, are/is axially variable such that in particular production errors can be much better compensated for. This is because the clamping bushings 60, 61 make it possible to bring about two states, namely on one hand the state in which the respective bushings can move axially in the clamping bushings, and on the other hand the second state in which the clamping bushings are clamped in a force-fitting manner with the respective bushings therein.

[0052] It is however also conceivable, in a simplified embodiment, that only one of the bushings is guided in a clamping bushing, such that, once the force-fitting connection between the bushings has been established, with the aid of the clamping bushing 60, the corresponding slide bushing can be connected in a force-fitting manner.

[0053] Furthermore, the exemplary embodiment of FIG. 5 provides that the bushings have teeth 70 that engage with respectively matching teeth of the adjacent bushing such that, in addition to the force-fitting clamping, the bushings are also connected in a form-fitting manner. This additionally secures against the blade segments moving with respect to one another in the Z-direction. Thus, in the exemplary embodiment of FIG. 5, it is provided that the slide bushing 51 of the web section 41a has teeth 70 which engage with teeth of the through-bushing 52, the flanged bushing 57 of the web section 41b also having teeth 70 which engage with the teeth of the through-bushing 52 on that side.

[0054] The flanged bushings 50 can for example be adhesively bonded in the web sections 41a, 41b in order to thus permit a solid connection. Furthermore, the through-bushing 52 of the inner spar element 21 can also be adhesively bonded in the respective web sections 43a, 43b.

[0055] In order to achieve as high a weight-saving potential as possible, it is advantageous if both blade segments are made of a fiber-reinforced composite material, or at least comprise such a material.

LIST OF REFERENCE SIGNS

[0056] 10 segmented rotor blade [0057] 11 first blade segment [0058] 12 second blade segment [0059] 13 trailing edge [0060] 14 junction [0061] 15 leading edge [0062] 16 trailing edge strip [0063] 20 spar connector [0064] 21 spar element of the first blade segment [0065] 22 spar element of the second blade segment [0066] 23 connection region [0067] 24 cavity of spar element 22 [0068] 30 screw connection [0069] 40a, 40b—flange section of spar element 22 [0070] 41a, 41b—web section of spar element 22 [0071] 42a, 42b—flange section of spar element 21 [0072] 43a, 43b—web section of spar element 21 [0073] 50 flanged bushing [0074] 51 slide bushing [0075] 52 through-bushing [0076] 53 connection bolt/screw [0077] 54 screw head [0078] 55 nut [0079] 56 threaded ring [0080] 57 flanged bushing with internal thread [0081] 58 slide bushing with internal thread [0082] 60, 61 clamping bushing [0083] 70 teeth