CONNECTION BETWEEN LONGITUDINAL SEGMENTS OF A ROTOR BLADE OF A WIND TURBINE ROTOR

Description

[0001] The invention relates to a connection between sections of a rotor blade of a wind turbine, divided transversely to its longitudinal axis, wherein the rotor blade has a hollow airfoil profile with a low-pressure side wall shell and a high-pressure side wall shell, and a spar extending in the cavity between the wall shells in the longitudinal direction of the blade, which is connected to the wall shells via chord parts of the spar facing the wall shells, wherein the chord parts of the spar of the rotor blade sections are widened in a connection area to form opposing butt surfaces, such that recesses for receiving connecting elements projecting from the opposite butt surface open in at least one of the butt surfaces, which are only open in the butt surfaces for receiving connecting elements projecting from the opposite butt surface, and that the connecting elements are anchored in the receiving recesses in a material-locking manner.

[0002] Such a connection is known from WO 2010 / 086297 A1.

[0003] Further connections are shown from EP 1 761 702 B1, EP 2 815 861 A1, EP 2 881 580 A1 and EP 3 064 768 A1.

[0004] As rotor blade length increases, cross-sectioning offers advantages in terms of transport and manufacturing. Rotor blades consisting of rotor blade sections are known, for example, from EP 1 761 702 B1, US 9,506,452 B2, EP 2 740 583 B1 and EP 2 264 310 B1.

[0005] The present invention provides a new connection between sections of a rotor blade of the type mentioned above, characterized in that the connecting elements are furthermore positively anchored in the receiving recesses and the receiving recesses are undercut.

[0006] While the wall shells largely contain filler material without load-bearing function, the spar is primarily responsible for the strength of the rotor blade. According to the invention, its flange sections, which are widened in the connection area, are incorporated into the connection in such a way that they serve as carriers for a multitude of connecting elements, by which the butt ends of the rotor blade sections are held together. The rotor blade according to the invention can thus be subjected to tensile and compressive stresses in the same way as a continuous rotor blade.

[0007] In one embodiment of the invention, the connecting elements are integrally connected to the belt section forming the other impact surface. Alternatively, the connecting elements are separate parts that extend into receiving recesses that are aligned in pairs and open in both impact surfaces.

[0008] Advantageously, in the latter embodiment, the connecting elements are designed as pin connecting elements with a preferably circular cross-section, which can engage in bores with a corresponding cross-section forming the receiving recesses.

[0009] For practical purposes, connecting elements that are integrally connected to one of the belt parts have a flat cross-section and engage in receiving recesses that are designed as narrow pockets.

[0010] The connecting elements, which are integrally connected to one of the belt parts, can be formed, for example, by laminate layers that protrude from the belt part to which they are connected.

[0011] In another embodiment, the connecting element can be deformed, for example, to allow it to be inserted into the receiving recess.

[0012] In a further embodiment of the invention, at least one of the widened belt parts is formed by a prefabricated component that is completely bonded to the rest of the spar.

[0013] The thickness of the wall panels is advantageously reduced in the area of ​​the connection with the flange section, so that, with respect to its thickness, the flange section partially takes over the function of the wall panel in this area. In extreme cases, the thickness of the wall panel in this area can approach zero.

[0014] It is advantageous to arrange the aforementioned boreholes close to the wall shell in the widened belt sections in a line running parallel to the cross-sectional contour of the respective wall shell.

[0015] The support surfaces for the belt parts forming the wall shells can be widened in width and / or thickness, with the bores being arranged, for example, not only in one, but in several rows parallel to the outer contour of the wall shell in question.

[0016] In one embodiment, the chord sections of the spar are widened by a laminate structure that is bonded to an end piece of the remaining chord section, preferably an end piece that tapers by scarf jointing. The laminate structure forming the widening is then scarf-jointed in the opposite direction.

[0017] The thickness of an end area of ​​the widening can decrease slightly towards the impact surface if the scarf joint is reversed again.

[0018] The spar expediently features a double-T profile and / or a box profile. The chord sections are then formed by the T-legs of the double-T profile or opposing legs of the box profile.

[0019] In the connection area, the widened belt sections, parallel to the wall shells, can be supported by connecting parts opposite the rest of the beam, which absorb additional shear forces.

[0020] The opposing butt surfaces can abut each other and, if necessary, be bonded together, sealing the rotor blade interior. Preferably, however, a small gap is formed between the butt surfaces so that the flared belt sections and, in particular, the end faces of the wall shells cannot interact at the joint. The gap at the joint can be closed by a thin cover that wraps around the rotor blade.

[0021] In a further embodiment of the invention, the pin connecting element has a thickening, wherein, in particular, the opposing butt surfaces in the connection area are arranged in the region of this thickening. The thickening ensures increased tensile and shear strength with low mass of the pin connecting elements.

[0022] Preferably, the thickening of the pin connecting elements is conically shaped, avoiding stepped sections at the ends.

[0023] The thickening can be formed by at least one sleeve placed on a pin body and, in particular, secured by adhesive bonding. Pin bodies and sleeve material are available as finished products. Accordingly, the effort required to manufacture such pin connectors is minimal.

[0024] In a further embodiment, channels opening towards the inside or outside of the sheet lead into the blind bores for injecting adhesive compound, as well as channels for checking the filling of a gap between the pin connecting element and the bore wall. Preferably, the control channels are grooves formed in the mating surfaces.

[0025] Alternatively, sufficient quantities of adhesive can be poured into the receiving recesses that open in the butt surfaces for bonding.

[0026] Radial spacers can protrude from the pin connecting element to center the pin element within the bore.

[0027] The connecting elements and receiving recesses within a connection can differ in shape, dimensions and material.

[0028] The connecting element, the stiffening belt including the flares and / or the wall shells are preferably made of fiber composite material. In particular, the flared belt sections and, if applicable, the wall shells are each a fiber composite structure.

[0029] The rotor blade sections preferably comprise a section comprising the free end of the rotor blade and a section comprising the blade root of the rotor blade. However, at least one of the sections described above could also be connected at both ends to another rotor blade section.

[0030] In another embodiment, the rotor blade sections can each have a cover at the connection end that protects the interior of the rotor blade section.

[0031] The invention is further explained below with reference to exemplary embodiments and the accompanying drawings relating to these exemplary embodiments. The drawings show: Fig. 1 shows a section of a rotor blade made of rotor blade sections connected according to the invention, Fig. 2 shows a connecting end of one of the Fig. 1 The rotor blade sections shown in plan view, Fig. 3 a cross-section according to section plane II of the rotor blade of Fig. 1Fig. 4 shows an embodiment of a connection using a pin connecting element in a detail, Fig. 5 shows a connection of Fig. 4 pin connecting element used, Figs. 6 and 7 details of a further embodiment for a connection, Figs. 8 and 9 an embodiment for a belt part of a rotor blade section widened according to the invention in different views, Figs. 10 and 11 further embodiments for connections, and Fig. 12 a further embodiment for a connection according to the invention.

[0032] A in Fig. 1 The partially shown rotor blade 1 of the rotor of a wind turbine (not otherwise shown) is divided transversely and, in this example, has two rotor blade sections 2 and 3, one of which comprises the blade root and the other the free blade tip (blade root and tip not visible). At point 4, a connection area is formed between rotor blade sections 2 and 3.

[0033] Rotor blade sections 2 and 3 have a hollow shape, in Fig. 3 The cross-sectional view shows a wing profile with a wall shell 5 on the negative pressure side and a wall shell 6 on the positive pressure side. Fig. 1 shows the respective underprinted sides in a top view.

[0034] Between the wall shells 5, 6 extends a spar 7, which crosses the cavity of the wing profile and runs in the longitudinal direction of the blade. The in Fig. 3 The cross-section of the beam 7 shows a double-T profile with flange sections 8, 9 parallel to the wall panels 5, 6. The flange sections 8, 9 engage in recesses in the wall panels 5, 6 and are bonded to the wall panels 5, 6 over their entire surface. In this example, the vertical leg of the double-T profile is formed by two webs 10.

[0035] In the connection area 4, the belt sections 8, 9 are widened towards the connection end of the rotor blade sections 2, 3 and, if necessary, thickened section by section. At the respective connection end, the widened belt sections 8, 9, connected to the wall shells 5, 6, each form a butt surface 11 or 12.

[0036] In the butt surfaces 11, 12 of the rotor blade sections 2, 3, which are mirror images of each other in the connection, bores 13 open, which are arranged according to a line running along the contour of the wall shells 5, 6, as Fig. 2 This can be seen. At the connection point between rotor blade sections 2 and 3, the relevant bores 13 of rotor blade section 2 are axially aligned opposite the corresponding bores 13 of rotor blade section 3.

[0037] Each of the aligned bores 13 is fitted with a pin connecting element 14, in the example shown approximately half its length. The pin connecting elements 14 are fixed in the bores 13 by a material-fit connection.

[0038] In addition to the webs 10 of the spar 7, which preferably extend in a straight line into the connection area 4, the following could deviate from Fig. 2 Additional shear-absorbing connections must be made between the widened belt sections 8,9, as shown in dashed lines 24 in Fig. 2 to suggest.

[0039] In the described example, both the pin connecting elements 14 and all parts of the rotor blade sections 2,3 shown are preferably made of fiber composite material, including carbon fiber composite material, wherein in particular the spar 7 including expansions is designed as a fiber composite structure.

[0040] The in Fig. 1The schematically represented pin connecting elements 14 can have a thickening according to Fig. 4 and Fig. 5 exhibiting. The thickening 15, arranged in the longitudinal center of the pin connection element 14 in the example, is arranged symmetrically to the joint between the connected rotor blade sections 2, 3. According to Fig. 4 The pin connecting element 14 is fixed in the mirror-image bores 13 by a hardened adhesive layer 16. In this example, an adhesive layer 17 is also formed between the abutting surfaces 11, 12, in which the mirror-image bores 13 open to receive the pin connecting elements 14.

[0041] The thickening 15 of the in Fig. 4The pin connecting element 14 shown in the example is formed by a sleeve 19 that is pushed onto a pin body 18 and fixed by adhesive bonding. At each of its ends, the sleeve 19 has a conical taper 20. The cross-sectional area of ​​the pin connecting element 14 is completely circular.

[0042] The bore 13, widened according to the thickening 15, can advantageously be produced in a single operation using a correspondingly shaped drilling tool.

[0043] According to Fig. 6A channel 22 leading to the outside of rotor blade section 2, 3 can open into the bore 13, which receives the pin connecting element 14. Adhesive compound can be injected through this channel into a gap between the pin connecting element 14 and the wall of the bore 13. Advantageously, the channel 22 opens at the closed end of the bore 13. At least one inspection channel leading to the outside of rotor blade section 2 or 3 can open into the bore 13 at the open end. Advantageously, a groove 23 formed in the butt surface 11 or 12 serves as the inspection channel. It is understood that the channel 22 or the groove 23 can also open towards the inside of the rotor blade.

[0044] According to Fig. 7For example, four such grooves 23 can open into the bore 13 at points distributed around the circumference of the bore 13. Adhesive material 16 emerging from the groove channels 23 indicates that the adhesive gap between the pin connecting element 14 and the bore wall is completely filled with adhesive.

[0045] For example, radially projecting spacers can be attached to the pin connecting element 14 from a support ring, which center the pin connecting element 14 within the bore 13 and ensure a sufficient gap thickness all around for the absorption of adhesive.

[0046] Figures 8 and 9Figure 1 shows an embodiment for an expansion area 21 of the belt section 8 or 9. In the expansion area 21, the remaining area of ​​the belt section, which has a constant cross-sectional area, transitions into an end section 25 with decreasing thickness. The reduction in thickness is achieved by progressively reducing the number of laminate layers, a process known as scarfing.

[0047] The scarfed end section 25 is connected to a reverse scarfed laminate structure 26, through which the belt section 8 or 9 increases in both thickness and width up to an end region 27 having the butt joint 11 or 12. Placeholder fillings 29, e.g., made of foam or balsa, are located next to the end section 25 between layers of the laminate structure 26.

[0048] The end section 27 again has a scarf joint like the end section 25, i.e. its thickness decreases slightly towards the butt surface 11 or 12.

[0049] In the example shown, the width of belt section 8 or 9 increases from 0.7 m to 1 m and the thickness from 23 mm to 100 mm.

[0050] The widening area 21 could also be completely prefabricated and glued to the spar as a whole.

[0051] It will now be referred to as Figures 10 to 12 Reference is made where identical or equivalent parts are designated with the same reference number as in the preceding figures and the letter a or b is added to the respective reference numbers.

[0052] One in the Figures 10 and 11 The embodiment shown uses pin-like connecting elements 14a instead of pin connecting elements, which are integrally connected to flared belt parts 8a and 9a of a spar 7a.

[0053] How Fig. 11As can be seen, the pin-like connecting elements 14a have a flat cross-section and engage in slot-shaped receiving recesses 13a in correspondingly widened strap sections of a spar 7a' of the rotor blade section 2a. The connecting elements 14a are anchored in the receiving recesses 13a by previously applied and cured adhesive.

[0054] The tenon-like, flat-section connecting elements 14a consist of laminate layer sections that protrude from the expanded strap section, which itself is formed from laminate layers. The slot-shaped receiving recesses 13a are formed, for example, by cores that were removed after the respective strap sections were laminated.

[0055] At a Fig. 12In the partially illustrated embodiment, slot-shaped receiving recesses 13b are undercut, and deformable, pin-like connecting elements 14b engage in the receiving recesses for insertion. The deformability of the connecting elements 14b results from a wedge-shaped cut 30 with a widening at the closed end. The cut 30 forms compressible legs that spread open again after the connecting element 14b is inserted into the receiving recess 13b. Fig. 12 As can be seen, the wedge-shaped cutout is filled with hardened adhesive compound 16b.

Claims

1. Connection between portions (2, 3) of a rotor blade (1) of the rotor of a wind turbine, said rotor blade being split transversely to its longitudinal axis, wherein the rotor blade (1) has a hollow aerofoil profile, with a negative-pressure-side wall shell (5) and a positive-pressure-side wall shell (6), and has a spar (7) which extends in the cavity between the wall shells (5, 6) in the blade longitudinal direction and which is connected to the wall shells (5, 6) via cap parts (8, 9) of the spar (7), said cap parts being directed towards the wall shells (5, 6), wherein the cap parts (8, 9) of the spar (7) of the rotor-blade portions (2, 3) are widened in a connecting region (4) such that mutually oppositely situated abutment surfaces (11, 12) are formed, in that, in at least one of the abutment surfaces (11, 12), there open cutouts (13) for receiving connecting elements (14) projecting from the oppositely situated abutment surface, said cutouts being open only in the abutment surfaces (11, 12) for receiving connecting elements (14b) projecting from the oppositely situated abutment surface, and in that the connecting elements (14) are anchored in a materially bonded manner in the receiving cutouts (13), characterized in that the connecting elements (14b) are furthermore anchored in a form-fitting manner in the receiving cutouts (13b) and the receiving cutouts (13b) are undercut.

2. Connection according to Claim 1, characterized in that the connecting elements (14, 14a) are connected in one piece to the cap part forming the oppositely situated abutment surface or extend into receiving cutouts (13) aligned with one another in pairs in both mutually oppositely situated cap parts.

3. Connection according to Claim 1 or 2, characterized in that the connecting elements (14) are pin-type connecting elements having a preferably circular cross section, and the receiving cutouts are bores (13), in particular blind bores, having a cross section preferably in the form of a circle.

4. Connection according to one of Claims 1 to 3, characterized in that the connecting elements (14a) have a flat cross section, and the receiving cutouts are in the form of correspondingly narrow pockets (13a).

5. Connection according to one of Claims 2 to 4, characterized in that the connecting elements (14a) connected in one piece to the oppositely situated abutment surface are formed by portions of laminate layers projecting from the respective cap part.

6. Connection according to one of Claims 1 to 5, characterized in that the connecting elements (14b) are deformable for introduction into the receiving cutouts.

7. Connection according to one of Claims 1 to 6, characterized in that an end portion having at least one of the widened cap parts (8,9) is completely prefabricated and is adhesively bonded to the rest of the spar (7).

8. Connection according to one of Claims 1 to 7, characterized in that the cap parts (8,9) are widened in width.

9. Connection according to Claim 8, characterized in that the cap parts (8,9) are widened in thickness.

10. Connection according to one of Claims 1 to 9, characterized in that the cap parts (8,9) are widened by way of a laminate structure (26) which is connected to an end piece of the rest of the cap part, in particular to a tapering end piece (25).

11. Connection according to one of Claims 1 to 10, characterized in that the pin-type connecting element (14) has a thickened portion (15), and in particular the abutment surfaces (11,12) abutting against one another in the connecting region (4) are arranged in the region of the thickened portion (15), wherein the pin-type connecting element (14) preferably comprises conical widened portions (20) for forming the thickened portion (15).

12. Connection according to Claim 11, characterized in that the thickened portion (15) is formed by at least one sleeve (19) which is placed onto a pin main body (18) and is fastened in particular by adhesive bonding.

13. Connection according to one of Claims 1 to 12, characterized in that channels (22) opening in each case to the blade outer side and serving for injection of adhesive compound and such channels (23) for checking the filling of a gap between the pin-type connecting element (14) and the bore wall open out into the blind bores (13), wherein preferably the checking channels are formed by groove channels (23) formed in the abutting surfaces (11,12).

14. Connection according to one of Claims 1 to 13, characterized in that the pin-type connecting element (14), the spar (7), with the widened portions included, and / or the wall shells (5,6) consist(s) of fibre composite material, and in particular the spar (7), with its widened portions included, and possibly the wall shells have a fibre composite structure.

15. Connection according to one of Claims 1 to 14, characterized in that the rotor-blade portions (2,3) have at the connecting end in each case one cover which protects the interior space of the rotor-blade portion and which is connected fixedly or releasably to the rotor-blade portion.