ROTOR BLADE, METHOD FOR MANUFACTURING A ROTOR BLADE FOR A WIND ENERGY INSTALLATION, AND A WIND ENERGY INSTALLATION

Abstract

A rotor blade for a wind energy installation includes a blade root, a blade tip, and at least one rotor blade shell extending in a longitudinal direction from the blade root to the blade tip, and having an inner shell region and an outer shell region. The inner shell region includes a first fiber composite with at least two first fiber layers, and the outer shell region includes a second fiber composite with at least two second fiber layers. The first and second fiber layers extend substantially in the longitudinal direction. At least a first fiber layer of the first fiber composite terminates in the region of at least one end position in the longitudinal direction, whereas the remaining first fiber layers extend beyond the end position. At least a second fiber layer of the second fiber composite terminates in the region of the end position in the longitudinal direction, whereas the remaining second fiber layers extend beyond the end position.

Claims

1. A rotor blade (1) for a wind energy installation, wherein the rotor blade (1) comprises a blade root (2), a blade tip (3), and at least one rotor blade shell (4, 5) which extends in a longitudinal direction (L) from the blade root (2) to the blade tip (3) and which comprises an inner shell region (9) and an outer shell region (10), wherein the inner shell region (9) comprises a first fiber composite which comprises at least two first fiber layers (11, 12), and wherein the outer shell region (10) comprises a second fiber composite which comprises at least two second fiber layers (13, 14), and wherein the first and second fiber layers (11-14) extend substantially in the longitudinal direction (L), characterized in that at least a first fiber layer (11) of the first fiber composite terminates at, or in the region (ΔE) of, at least one end position (E) in relation to the longitudinal direction (L), whereas the remaining first fiber layers (12) of the first fiber composite extend beyond the end position (E), and at least a second fiber layer (13) of the second fiber composite terminates at, or in the region (ΔE) of the same end position (E) in relation to the longitudinal direction (L), whereas the remaining second fiber layers (14) of the second fiber composite extend beyond the end position (E).

2-8. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the principles of the invention.

[0020] FIG. 1 depicts an example of a rotor blade in a side view;

[0021] FIG. 2 depicts an example of a cross section through a rotor blade transverse to the longitudinal direction;

[0022] FIG. 3 depicts an example of a cross section through a portion of a rotor blade shell in the longitudinal direction; and

[0023] FIG. 4 depicts an example of a cross section through a rotor blade shell along the length of the blade.

DETAILED DESCRIPTION

[0024] FIG. 1 shows a side view of an example of a rotor blade 1 which extends in a longitudinal direction L from a blade root 2, at which the rotor blade 1 is connected to the hub (not shown) of a wind energy installation, to a blade tip 3.

[0025] FIG. 2 shows an example of a cross section A-A through the rotor blade 1 shown in FIG. 1, perpendicular to the longitudinal direction L. The rotor blade 1 preferably has a first rotor blade shell 4 which is located in the area of the pressure side DS, as it is referred to, of the rotor blade 1, and a second rotor blade shell 5 which is located in the area of the suction side SS, as it is referred to, of the rotor blade 1.

[0026] The two rotor blade shells 4, 5 are connected to each other, for example glued to each other, in each of the area of the nose 6, as it is referred to, and the trailing edge 7, as it is referred to, of the rotor blade 1. Further, one or more spars or webs 8 can be provided, which are bonded to the two rotor blade shells 4, 5, in particular via a respective suction side and pressure side rotor blade chord.

[0027] The rotor blade shells 4, 5 each have an inner shell region 9 and an outer shell region 10, wherein the inner shell region 9 is formed by a first fiber composite of first fiber layers and the outer shell region 10 is formed by a second fiber composite of second fiber layers. This is further illustrated below with reference to FIG. 3.

[0028] FIG. 3 shows an example of a cross section B-B through a portion of a rotor blade shell 4, 5 in the longitudinal direction L, which section is located near the blade tip 3 of the rotor blade 1 (see FIG. 1).

[0029] In the portion shown, the rotor blade shell 4, 5 has an inner shell region 9, which is formed by a first fiber composite, which has two first fiber layers 11, 12 in a left-hand part of this portion, and only one first fiber layer 12 in a right-hand part of this portion. Further, in the portion shown, the rotor blade shell 4, 5 has an outer shell region 10, which is formed by a second fiber composite, which has two second fiber layers 13, 14 in the left-hand part of this portion, and only one second fiber layer 14 in the right-hand part of this portion. The first and second fiber layers 11 to 14 preferably extend substantially in the longitudinal direction L of the rotor blade.

[0030] The neutral fiber N is also illustrated (as a line in which dots alternate with dashes) in the portion of the rotor blade shell 4, 5 shown. The neutral fiber N, which is also referred to as the “neutral axis” or “zero line”, is to be understood as that line, plane or (partial) layer in the cross section of the rotor blade shell 4, 5 whose length does not change when the rotor blade shell 4, 5 is twisted and/or bent, for example. In the region of the neutral fiber N, a load does not cause any tensile or compressive stress. By way of contrast, the tensile or compressive stress increases with the distance from the neutral fiber N in the direction perpendicular thereto, for example in the case of a tensile load on the rotor blade shell during operation of the rotor blade, and is, as a rule, at a maximum at the surface of the inner shell region 9 and the outer shell region 10, respectively.

[0031] In the example shown, a first fiber layer 11 of the first fiber composite of the inner shell region 9 terminates in a region ΔE around an end position E in relation to the longitudinal direction L, whereas the remaining first fiber layer 12 of the first fiber composite extends further in the longitudinal direction L beyond the end position E.

[0032] Further, a second fiber layer 13 of the second fiber composite of the outer shell region 10 terminates in the region ΔE around the same end position E, whereas the remaining second fiber layer 14 of the second fiber composite extends further in the longitudinal direction L beyond the end position E.

[0033] In this way, on the one hand, the wall thickness of the rotor blade shell 4, 5, in particular the sum of the respective thicknesses of the individual layers of the inner shell region 9 and of the outer shell region 10, can be reduced and, on the other hand, a possible jump in the stiffness and/or a possible offset V of the neutral fiber N in the region ΔE around the end position E associated with the reduction in thickness can be kept low.

[0034] For example, the offset V of the neutral fiber N would be greater if, in the present example, a reduction in the thickness by only one fiber layer only in the inner one of the two shell regions 9 had been carried out.

[0035] Further, although the offset V of the neutral fiber N would be of a similar amount if, in the present example, a reduction in the thickness by one fiber layer had been carried out only in the outer one of the two shell regions 10. However, an induced bending load would result, which, when the shell is subjected to a tensile load, leads to an additional tensile stress on the outer side and a compressive stress on the inner side. Since the outer side is generally subjected to higher stresses due to the bending of the rotor blade, the induced compressive stress is additionally detrimental to the construction.

[0036] By keeping an offset V in the neutral fiber N of the rotor blade shell 4, 5 low in this way, the tensile forces acting on the rotor blade shell 4, 5 during bending of the rotor blade generate lower bending moments in the region of the location or locations at which the wall thickness of the rotor blade shell has been reduced in this way, so that compressive stresses on the outer side of the rotor blade shell and/or tensile stresses on the inner side of the rotor blade shell resulting therefrom can be kept low.

[0037] In principle, it is particularly advantageous if the first fiber layer or layers 11 and the second fiber layer or layers 13 terminate as precisely as possible at the same end position E, or at least substantially at the same end position E. However, the advantages of the invention already become noticeable if the first fiber layer or layers 11 and the second fiber layer or layers 13 terminate within a finite area ΔE around the same end position E. The width of the area ΔE around the end position E is preferably of the order of magnitude of the thickness D1 of the terminating first fiber layer or layers 11 and/or the thickness D2 of the terminating second fiber layer or layers 13. For example, the width of the area ΔE in this case is k×D1 or k×D2, where k is between 0.5 and 50, in particular between 1 and 20.

[0038] FIG. 4 shows an example of a cross section through a rotor blade shell 4, 5 over the entire blade length in the longitudinal direction L. In this example, the wall thickness of the rotor blade shell 4, 5 has been reduced at a total of six end positions E1 to E6 analogously to the example explained above in connection with FIG. 3, for example in that, at the first end position E1, each of a first fiber layer of a first fiber composite, for example a first fiber composite which has a total of seven first fiber layers, terminates at the inner shell region 9, and a second fiber layer of a second fiber composite, for example a second fiber composite which has a total of seven second fiber layers, terminates at the outer shell region 10, whereas the respective remaining six first fiber layers and six second fiber layers extend further in the longitudinal direction L beyond the first end position E1.

[0039] In a corresponding manner, the wall thickness of the rotor blade shell 4, 5 can be reduced at the further end positions E2 to E6 by each of one first fiber layer and one second fiber layer, so that only one first fiber layer and one second fiber layer are present in the region of the blade tip.

[0040] Of course, however, a larger and/or a smaller total number of first fiber layers and/or second fiber layers can also be provided. In addition, or as an alternative, the number of first fiber layers and second fiber layers, each of which terminate at one of the end points E1 to E6, can also be greater than 1.

[0041] Preferably, the area between the outer shell laminate and the inner shell laminate 9 and 10, respectively, is formed by a layer of core material.

[0042] In a particularly advantageous manner, the end of the layer of the inner shell laminate and/or of the outer shell laminate 9 and 10, respectively, is located such that it faces towards the neutral fiber N. In other words, the inner shell laminate and/or the outer shell laminate 9 and 10, respectively, preferably always terminates with the respective inner layer. By means of this, a free end at the surface can be avoided.

[0043] While the present invention has been illustrated by a description of various embodiments, and while these embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such de-tail. The various features shown and described herein may be used alone or in any combination. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method, and illustrative example shown and described. Accordingly, departures may be made from such details without departing from the spirit and scope of the general inventive concept.