METHOD FOR MANUFACTURING A ROOT SEGMENT OF A ROTOR BLADE OF A WIND TURBINE

Abstract

A method for manufacturing a root segment of a rotor blade of a wind turbine includes the steps of: providing multiple root segment sections of the root segment to be manufactured; drilling first holes into each one of the provided root segment sections to obtain drilled root segment sections; arranging the multiple drilled root segment sections in a mold; and casting the multiple drilled root segment sections arranged in the mold to obtain the root segment.

Claims

1. A method for manufacturing a root segment of a rotor blade of a wind turbine, the method comprising: providing multiple root segment sections of the root segment to be manufactured; drilling first holes into each one of the provided root segment sections to obtain drilled root segment sections; arranging the multiple drilled root segment sections in a mold; and casting the multiple drilled root segment sections arranged in the mold to obtain the root segment.

2. The method according to claim 1, wherein the first holes are being drilled substantially perpendicular to connection face portions of the root segment sections.

3. The method according to claim 1, further comprising the step of placing each one of the multiple root segment sections in a predetermined position on a first fixture such that the step of drilling the first holes is performed in the predetermined position.

4. The method according to claim 1, wherein the step of drilling the first holes comprises usage of a first drilling jig.

5. The method according to claim 3, when the first drilling jig is provided at the first fixture.

6. The method according to claim 1, further comprising the step of attaching the drilled root segment sections to the mold by fastening the drilled root segment sections to the mold via bolts and/or pins inserted into the first holes of the drilled root segment sections.

7. The method according to claim 1, further comprising drilling second holes transverse to and at least partially through the first holes in the root segment.

8. The method according to claim 7, wherein the drilling of the second holes comprises usage of a second fixture having a second drilling jig.

9. The method according to claim 8, wherein the second fixture comprises a mounting arrangement mounting the second fixture on the root segment.

10. The method according to claim 9, wherein the mounting arrangement comprises alignment pins, the alignment pins being spaced apart from the second drilling jig and from one another, and the alignment pins being configured for being inserted into the first holes.

11. A fixture for assisting in a method for manufacturing a root segment of a rotor blade of a wind turbine, wherein the fixture is configured for supporting at least one root segment section of the root segment to be manufactured in a predetermined position, or the fixture comprises a mounting arrangement configured for being mounted onto the root segment, and wherein the fixture comprises a drilling jig for drilling holes into the root segment sections, or the root segment or the fixture comprise a root plate with holes for fastening the at least one drilled root segment section to the root plate via bolts and/or pins inserted through the holes of the root plate and holes inside of the at least one drilled root segment section.

12. The fixture according to claim 11, wherein the fixture is configured for supporting a root segment section of the root segment to be manufactured in a predetermined position, and whereby the drilling jig on the fixture is configured such that the drilling jig of the fixture is aligned with the root segment section placed in the predetermined position of the fixture for drilling first holes into the root segment section to obtain a drilled root segment section.

13. The fixture according to claim 11, wherein the fixture is a mold configured for supporting multiple root segment sections of the root segment to be manufactured in predetermined positions, in which the multiple root segment sections form at least part of the root segment, and whereby the mold comprises a root plate with holes for fastening the root segment sections to the root plate via bolts and/or pins inserted through the holes of the root plate and holes inside of the root segment sections.

14. The fixture according to claim 11, wherein the mounting arrangement comprises alignment pins, the alignment pins being spaced apart from the drilling jig; and from one another, and the alignment pins being configured for being inserted into the first holes.

15. A set comprising at least two different fixtures according to claim 11.

Description

[0035] Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

[0036] FIG. 1 shows a perspective view on a root segment of a rotor blade of a wind turbine;

[0037] FIG. 2 shows a method of drilling holes into the root segment of the rotor blade of FIG. 1 according to the prior art;

[0038] FIG. 3 shows a perspective view on the root segment of the rotor blade of FIG. 1 having holes drilled therein;

[0039] FIG. 4 shows a perspective view on a connection means for attaching the root segment of the rotor blade of FIG. 3 to a hub of a wind turbine;

[0040] FIG. 5 shows a perspective view on the root segment of the rotor blade of FIG. 3 having installed therein the connection means of FIG. 4:

[0041] FIG. 6 shows a perspective view on a root segment section of a root segment of a rotor blade to be manufactured;

[0042] FIG. 7 shows a perspective view on the root segment section placed in a predetermined position on a first fixture;

[0043] FIG. 8 shows a perspective view on the root segment of FIG. 6 having first holes drilled therein;

[0044] FIG. 9 shows a cross-section of the drilled root segment of FIG. 8 together with a drilled second hole,

[0045] FIG. 10 shows an arrangement of multiple of drilled root segments according to FIG. 9 in a partial mold;

[0046] FIG. 11 shows an arrangement of multiple of drilled root segments according to FIG. 9 in a full mold;

[0047] FIG. 12 shows a root segment casted from the arrangement of FIG. 11;

[0048] FIG. 13 shows a perspective view of a second fixture for drilling second holes inside of the casted root segment of FIG. 12;

[0049] FIG. 14 shows a perspective view of the second fixture of FIG. 13 being mounted on the root segment of FIG. 12; and

[0050] FIG. 15 shows a schematic representation of the steps of a method for manufacturing the root segment of the rotor blade of FIG. 3.

DETAILED DESCRIPTION

[0051] FIG. 1 shows a portion of a rotor blade 1 for a wind turbine (not shown). The rotor blade 1 comprises a blade segment 2 extending from a root segment 3 to a tip (not shown) of the rotor blade 1, which is only shown partially in FIG. 1. At the root, the rotor blade 1 comprises the root section 3. The root section 3 has a cylindrical shape. The root section 3 has a connection face 4 with which it may be attached to a hub (not shown) of the wind turbine.

[0052] FIG. 1 shows the root segment 3 with no attachment means for attaching it to the hub. Typically, holes are drilled into the root segment 3 for later inserting barrel nuts and bolts therein for the connection with the hub as will be explained later.

[0053] FIG. 2 shows the method of how the holes 5 are drilled into the root segment 3 in the prior art. An automated drilling root machine 6 is used in the prior art solution for drilling the hole 5. However, the semi-automated or automated drilling root machine 6 is expensive and inflexible.

[0054] FIG. 3 shows the rotor blade 1 of FIG. 1 with first holes 5 and second holes 7. The first holes 5 extend along the length or, in other words, lengthwise of the rotor blade 1. In particular, the first holes 5 extend substantially perpendicular to connection face portions 9 (see FIG. 6) of the multiple drilled root segment sections 8b, from which the root segment 3 is composed or manufactured and which, taken all together, form the connection face 4.

[0055] The second holes 7 extend perpendicular to the length or, in other words, to the lengthwise direction of the rotor blade 1. As may also be seen in FIG. 9, the second holes 7 extend substantially perpendicular to the first holes 5 and partially through one another or, in other words, such that both, the first holes 5 and the second holes 7, are connected with each other.

[0056] FIG. 4 shows the attachment means 10 consisting of barrel nut 11 and bolt 12 connected with one another as previously mentioned. The attachment means 10 serves the purpose of enabling the connection of the root segment 3 and thereby the rotor blade 1 to the hub of the wind turbine.

[0057] FIG. 5 shows how the barrel nuts 11 are inserted into the second holes 7 and connected via internal threads (not shown) of the barrel nuts 11 to external threads (not shown) of the bolts 12 inserted into the first holes 5. The free ends of the bolts 12 may serve for connecting them to the hub of the wind turbine.

[0058] FIG. 6 shows a single root segment section 8a with its connection face portion 9 as it is provided for casting the entire root segment 3 shown in FIG. 3. The root segment section 8a has a curved or partially circular shape. The root segment section 8a further is tapered in a direction away from the connection face portion 9.

[0059] FIG. 7 shows how the root segment section 8 is being placed in a predetermined single or, in other words, unique position on a first fixture 20. The first fixture 20 has connection beams 21 holding together a set of legs 22 by means of which the fixture 20 is rested on a ground. The legs 22 are arranged at a distance from one another corresponding to a width of the root segment section 8a such that the root segment section 8a may exactly fit onto the first fixture 20 in the shown position. A first drilling jig 23 or, in other words, drilling template, is attached to the first fixture 20. The first drilling jig 23 is attached to the first fixture 20 by means of bolts 25.

[0060] The first drilling jig 23 has a row of holes 24 for drilling the first holes 5 into the root segment section 8a. The holes 24 of the first drilling jig 23 are spaced apart from one another and sized corresponding to the design position of the first holes 5 to be drilled inside of the root segment section 8a. The connection face portion 9 of the root segment section 8a is in a predetermined position opposite of the first drilling jig 23 for accurately drilling the first holes 5 in the desired locations of the root segment section 8a.

[0061] FIG. 8 shows the root segment section 8a as a drilled root segment section 8b having the first holes 5 after the drilling operation has been conducted while the root segment section 8a was placed in the predetermined position on the first fixture 20 of FIG. 7.

[0062] FIG. 9 shows the already mentioned orientation of a first hole 5 being perpendicular to a second hole 7 in extension. The first hole 5 is drilled as previously explained with reference to FIGS. 6 to 8, and the shown second hole 7 is only drilled later and as shown with reference to FIG. 14. The first hole 5 extends from the connection face portion 9 to the second hole 7 or inside of the second hole 7.

[0063] FIG. 10 shows multiple of the drilled root segment sections 8b of FIG. 8 secured to a mold 30. The mold 30 has connection beams 31 and a set of legs 32 similar to the first fixture 20 of FIG. 7. Beam 31 and legs 32 can be removed or folded once the drilled root segment sections 8b are secured to mold 30 and assembled to the mold 30.

[0064] The mold 30 comprises a root plate 33 having multiple holes 34 corresponding in position to or, in other words, being aligned with the first holes 5 of the drilled root segment sections 8b when these are being placed on the mold 30 as seen in FIG. 10. The root plate 35 is secured to the mold 30 by means of bolts 36.

[0065] To keep the drilled root segment sections 8b in an accurate predetermined position without risking that the first holes 5 are misaligned during casting of the root segment 3, the root plate 33 is bolted through holes 34 and inside of the first holes 5 to the drilled root segment sections 8b by using bolts and/or pins 35, which may be press-fit.

[0066] FIG. 10 shows a mold 30 for half of the root segment 3 to be manufactured. In FIG. 11, another half of the root segment 3 having the root segment sections 8 attached thereto is being placed on top of the mold 30 of FIG. 10. Now, both molds 30 together enable the casting of the root segment 3. The casting may be done separately from the blade segment 2 or together with the blade segment 2, as shown in FIG. 11. Also, the casting can be single shot in case of an integral rotor blade 1. Casting can also be done by casting two halves in case of a bonded blade.

[0067] FIG. 12 shows the result of casting the rotor blade 1 shown in FIG. 11. The rotor blade 1 is provided as one part having the first holes 5 but not yet the second holes 7.

[0068] FIG. 13 shows a second fixture 40 for enabling accurate drilling of the second holes 7 inside of the casted root segment 3 such that the second holes 7 are oriented perpendicular to the first holes 5 and connect with them.

[0069] The second fixture 40 is not supported on the ground as is the case with the first fixture 20. Instead, the second fixture 40 is mounted on the root segment 3 as shown in FIG. 14, and the second holes 7 are drilled through the holes 44 provided in a second drilling jig 43 of the second fixture 40.

[0070] The second fixture 40 comprises a plate 41 at which the second drilling jig 43 is provided, in this exemplary case integrally formed. A number of alignment pins 45 is extending from the plate 41. The alignment pins 45 are designed to fit in the first holes 5 of the root segment 3. Accordingly, the pins 45 are sized to fit the first holes 5, and they have a distance from one another corresponding to the distance of the first holes 5 from one another. Moreover, the row of pins 45 follows a curved line corresponding to the curvature or circular shape of the root segment sections 8 and the first holes 5 provided therein.

[0071] The second fixture 40 is further provided with clamps 42. FIG. 13 shows four clamps 42, however, less or more than four clamps 42 may be used. Using at least four clamps 42 however is advantageous. It is possible to provide some of the clamps 42 on the second drilling jig 43 or extending therefrom, as seen in FIG. 13, and some of the clamps 42 on the plate 41 or extending therefrom. Accordingly, the clamps 42 on the second drilling jig 43 may secure the second fixture 40 from outside of the root segment 3 or on top of it, and the clamps 42 at the plate 41 may secure the second fixture 40 from inside of the root segment 3, as may be seen in FIG. 14.

[0072] The alignment pins 45 have a length shorter than the length of the first holes 5 such that the second holes 7 may be drilled in the root segment 3 without drilling through the alignment pins 45. The alignments pin 45 are aligned with the holes 44 in the second drilling jig 43 such that each central axis of an alignment pin 45 is perpendicular to a central axis of the hole 44.

[0073] FIG. 15 schematically shows the steps 101-106 of a method 100 for manufacturing the root segment 3 of the rotor blade 1 as shown in FIG. 3 and as previously explained with reference to FIGS. 4-14.

[0074] In the first step 101, multiple root segment sections 8a (see FIG. 6) of the root segment 3 to be manufactured are being provided.

[0075] In the second step 102, each one of the root segment sections 8a is consecutively placed on the first fixture 20 (see FIG. 7), and the first holes 5 are drilled inside of each of them.

[0076] Then, in the third step 103, the multiple drilled root segment sections 8b obtained in the previous step 102 are being arranged in the molds 30 (FIGS. 10 and 11). For this purpose, the drilled root segment sections 8b are being connected to the molds 30 via bolts 35 as previously explained.

[0077] Then, in the fourth step 104, the drilled root segment sections 8b attached to the mold 30 are casted together with the blade segment 2 to obtain the rotor blade 1.

[0078] In the fifth step 105, the second holes 7 are drilled into the root segment 3 of the rotor blade 1 as previously explained with reference to FIGS. 12-14.

[0079] Finally, in the sixth step 106, the attachment means 10 (FIG. 4) are provided inside of the first holes 5 and the second holes 7. Thereby, the rotor blade 1 is manufactured in a way such that it may now securely be connected to the hub of the wind turbine.

[0080] Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

[0081] For the sake of clarity, it is to be understood that the use of a or an throughout this application does not exclude a plurality, and comprising does not exclude other steps or elements.