Method for producing a rotor blade and rotor blade of a wind turbine

Abstract

The invention relates to a method for producing a rotor blade by arranging foam (23, 24) in a semi-finished product, introducing resin into the foam-containing semi-finished product, and curing the introduced resin while heat is dissipated and a curing temperature distribution is obtained, a first foam (23) being arranged in regions of the semi-finished product with a higher curing temperature, and a second foam (24) in regions with a lower curing temperature, and a foam with a higher temperature resistance than the second foam (24) being chosen as the first foam (23).

Claims

1. A method of producing a rotor blade, comprising a foam material (23, 24) arranged in a semi-finished product comprising a plurality of layers laying in a manufacturing mold, resin is introduced into the semi-finished product containing foam material, the resin introduced is hardened during the dissipation of heat and a hardening temperature distribution is produced in this case, characterized in that a first foam material (23) is provided in regions of the semi-finished product in which a first hardening temperature is set and a second foam material (24) is provided in regions in which a second hardening temperature is set, and the first foam material (23) selected is a foam material with a higher temperature resistance than the second foam material (24), and the first hardening temperature is made higher than the second hardening temperature and characterized in that at least one belt (7, 8) is arranged along the semi-finished product of a half shell (1, 2) of a rotor blade with longitudinal sides extending along the half shell (1, 2) of the rotor blade, and the first foam material (23) is arranged in a strip along the longitudinal sides of the at least one belt (7, 8) between the at least one belt (7, 8) and the second foam material (24).

2. A method according to claim 1, characterized in that the first foam material (23) is arranged along adhesion areas and/or along belts (7, 8).

3. A method according to claim 1, characterized in that the first foam material (23) is arranged in a strip directly along a front edge and/or rear edge (4, 6) of the semi-finished product of the half shell (1, 2) of the rotor blade, and is glued by means of an adhesion area along the front edge and/or rear edge (4, 6) to the front edge and/or rear edge (4, 6) of a corresponding half shell of the rotor blade (1, 2) and the second foam material (24) is arranged at a distance from the front edge and/or rear edge (4, 6).

4. A method according to claim 1, characterized in that the first foam material (23) is arranged in a semi-finished product of a web (3) having opposed bases (9, 11) along the web bases (9, 11).

5. A rotor blade comprising a foam material (23, 24) and a resin which is introduced into the foam material (23, 24) and hardens with the dissipation of heat and which forms a hardening temperature distribution, characterized in that a first foam material (23) is provided in regions of the semi-finished product in which a first hardening temperature is set and a second foam material (24) is provided in regions in which a second hardening temperature is set, and the first foam material (23) has a higher temperature resistance than the second foam material (24), and the first hardening temperature is higher than the second hardening temperature and characterized in that the half shell (1, 2) of the rotor blade and the corresponding half shell (1, 2) of the rotor blade have one belt (7, 8) in each case and the first foam material (23) is arranged in the form of a strip along the belts (7, 8) between the belts (7, 8) and the second foam material (24).

6. A rotor blade according to claim 5, characterized by a half shell (1, 2) of a rotor blade and a corresponding half shell (1, 2) of a rotor blade, and in that the first foam material (23) is arranged in the form of a strip along adhesion areas between front edges and/or rear edges (4, 6) of the half shells (1, 2) of the rotor blade in the form of a strip along the half shells (1, 2) of the rotor blade.

7. A rotor blade according to claim 5, characterized by a web (3), and in that the web (3) has opposed bases (9, 11) and the first foam material (23) is arranged in the form of a strip along the web bases (9, 11).

8. A rotor blade according to claim 5, characterized in that the first foam material (23) originates from the group PVC, SAN and PU.

9. A rotor blade according to claim 5, characterized in that the second foam material (24) is a polystyrene.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is described in a figure with reference to an embodiment. In this case FIG. 1 is a section at a right angle to the longitudinal direction of a rotor blade according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(2) FIG. 1 is a cross-section, not to scale, of the rotor blade according to the invention which is provided at a right angle to the longitudinal direction L which in the figure extends at a right angle to the plane of the drawing. Dark areas K represent adhesion areas, the areas A hatched to the right represent regions with first, high-temperature-resistant foam materials and the areas B hatched to the left represent regions with second, low-temperature-resistant foam materials.

(3) The rotor blade comprises a half shell 1 on the under-pressure side and a half shell 2 on the over-pressure side; the half shell 1 of the rotor blade on the under-pressure side is illustrated at the top in the figure and the half shell 2 of the rotor blade on the over-pressure side is illustrated at the bottom in the figure.

(4) The two half shells 1, 2 of the rotor blade are glued to each other on the front edges 4 thereof leading in the direction of rotation of the rotor blade in the assembled state and on the rear edges 6 thereof trailing in the operative state in the direction of rotation. The two half shells 1, 2 of the rotor blade glued to each other form an interior of the rotor blade. In particular, in order to increase the buckling rigidity and bending rigidity of the rotor blade a web 3 is arranged substantially in the portion of the largest internal distance of the two half shells 1, 2 of the rotor blade from each other. The web 3 connects the two inner walls of the half shells 1, 2 of the rotor blade to each other in a fixed manner and keeps them at a constant distance from each other. The web 3 is designed in the form of a single web in FIG. 1, but double webs and/or webs additionally extending along the rear edge 6 are also provided in other embodiments of the rotor blade according to the invention.

(5) The areas between the front edge 4 and the belts 7, 8 and the areas between the rear edge 6 and the belts 7, 8 are formed in a sandwich design which comprises a solid fibre-containing outer layer 21 and a solid fibre-containing inner layer 22 between which lower- and higher-temperature-resistant foam materials 23, 24 are arranged according to the invention.

(6) A high-temperature-resistant foam material 23 is arranged in each case both along an edgetowards the front edgeand an edgetowards the rear edgeof the belt 7 on the under-pressure side and of the belt 8 on the over-pressure side. The high-temperature-resistant foam material 23 extends along the entire edges of the belts 7, 8. The high-temperature-resistant foam material 23 separates the belts 7, 8 from the low-temperature-resistant foam material 24.

(7) In addition, a high-temperature-resistant foam material 23 is provided on the edge of the rotor blade half shell 1 on the under-pressure side extending along the front edge 4 as well as on the edge of the rotor blade half shell 1 on the under-pressure side extending along the rear edge 6. Corresponding remarks apply to the other rotor blade half shell 2 on the over-pressure side.

(8) In this way, starting from the front edge 4, the following sequence of materials is found in the case of the two half shells 1, 2 of the rotor blade along the cross-section in the interior of the shells: high-temperature-resistant foam material, low-temperature-resistant foam material, high-temperature-resistant foam material, belt, high-temperature-resistant foam material, low-temperature-resistant foam material, high-temperature-resistant foam material.

(9) The web 3 is likewise produced in the sandwich design, and it has two outer solid fibre-containing layers of fabric 31, 32 which embrace a low-temperature-resistant foam material 24, the web bases 9, 11 having a high-temperature-resistant foam material 23. The high-temperature-resistant foam material extends along the entire web base 9, 11 in the longitudinal direction L.

(10) In order to produce the rotor blades the two rotor blade half shells 1, 2 are produced separately from each other in production moulds provided therefor in each case. The web 3 is likewise produced separately in its own production mould.

(11) In order to produce the half shells 1, 2 of the rotor blade a plurality of lattice layers are laid one above the other in the respective production mould. The dry structure of the lattice is also referred to as a semi-finished product in this case. The layered structure of the half shells 1, 2 of the rotor blade varies along the cross-section. Belts 7, 8 extending in the longitudinal direction L of the half shells 1, 2 of the rotor blade are provided in the region of the greatest clear internal distance of the two half shells of the rotor blade from each other. The belts have a multiple-layer structure with fibre-containing, partially carbon-containing, lattice layers. The belts 7, 8 are particularly capable of being mechanically loaded.

(12) After the dry fibre-containing semi-finished product in a different consistency in cross-section is positioned on the mould, the semi-finished product is infused with a resin system.

(13) To this end, conventional RIM methods (resin injection moulding) can be used. The RIM method is a type of vacuum infusion method. In vacuum infusion methods a resin system is sucked into a laminate by vacuum pressure. The vacuum infusion method is usually characterized in that the dry fibre-containing semi-finished product inserted into the production mould is covered from the outside with a substantially air-tight vacuum foil and the edges thereof are glued to the production mould. Resin-supply lines extend by way of connections provided at preferably central points of the vacuum-tight foil into the interior which is closed in an air-tight manner and which accommodates the fibre-containing semi-finished product. The interior is surrounded by an annular vacuum line to which a vacuum pump is attached by way of a hose. After the vacuum pump is connected, an under-pressure, which also spreads inside the fibre-containing semi-finished product, is formed in the interior between the support face and the vacuum-tight foil. After that, the connection is opened and the resin system is sucked into the fibre-reinforced semi-finished product through the resin supply line. In this case care is taken in particular to prevent the formation of bubbles and to distribute the resin system uniformly inside the semi-finished product. If the fibre-reinforced semi-finished product is completely impregnated with the resin system, the supply of resin is interrupted and the vacuum pump is switched off.

(14) Resin systems which are generally used comprise a resin component and a hardener. The resin system starts the hardening process automatically while passing through an exothermic peak. The hardening procedure can quite possibly last several hours. Exothermic peaks can have temperatures of 180? C.; there are also resin systems, however, which have a lower exothermic peak at about 40? C. to 120? C.

(15) In order that the resin system should harden completely, the fibre-containing semi-finished product infused with the resin system has to be heated to a process temperature after passing through the exothermic peak. The process temperature has to be maintained over the entire infused area during the entire duration of the hardening.

(16) While passing through the exothermic peak the temperature distribution is different along the shell of the rotor blade of the same resin system used. During the production of the half shells 1, 2 of the rotor blade a higher process temperature occurs along the belts 7, 8 than in the area of the half shells 1, 2 of the rotor blade containing foam material. According to the invention therefore, a high-temperature-resistant foam material 23, which withstands the higher temperature stressing during the hardening procedure without being damaged, is provided in the areas adjacent to the belt, whereas a low-temperature-resistant foam material 24, which is less temperature-resistant, is provided in the other areas of the half shells.

(17) After the individual parts of the rotor blade 1, 2, 3 have been produced separately, they have to be glued to one another.

(18) The web has one base 9, 11 in each case on its narrow sides. During the assembly of the rotor blade the webs 3 are glued with one of their bases 9, 11 to one of the two opposed belts 7, 8 in each case along the belts 7, 8. There adhesion areas K are provided on each of the two web bases 9, 11. The two rotor blade half shells 1, 2 and the web 3 produced are glued to one another to form the rotor blade.

(19) An exothermic reaction also occurs during the adhesion procedure itself. In this case heat is developed in a manner dependent upon the thickness of the layer of adhesive and the geometry tolerances. The thicker the layer of adhesive, the more heat is developed and the hotter the layer of adhesive and the area surrounding it become.

(20) According to the invention a high-temperature-resistant foam material 23, which also withstands the adhesion procedure without being damaged, is likewise provided along the areas of the rotor blade half shells 1, 2 and the web 3 to be glued. The high-temperature-resistant foam material 23 is provided along the front edge 4 of the rotor blade half shells 1, 2 and the rear edge 6 of the rotor blade half shells 1, 2. In addition, the two narrow sides of the webs 3 facing the belts 7, 8, the web bases 9, 11, are completely formed by a high-temperature-resistantfoam material 23 which is also sandwiched by two outer layers in the region of the web bases 9, 11.

(21) The low-temperature-resistant foam material 24 is for example polystyrene, for example Compaxx? 900 of the firm Dow Chemical, with a temperature resistance of ?50? C. to +75? C., whilst the high-temperature-resistant foam material can be either PVC or PET, but it can also be SAN or PU foam materials, the temperature resistance of which is also above 180? C. After the hardening of the laminate is complete, the low-temperature-resistant foam material, in particular, should have the original mechanical properties, in particular the mechanical properties to be achieved by other foam materials, with respect to the rigidity and strength. In addition, during the hardening the foam material should have an adequate degree of rigidity and strength, so that significant deformation does not occur under vacuum pressure. The hardening procedure is also a suitable choice of a combination of the hardening temperature and the duration.

LIST OF REFERENCES

(22) 1 rotor blade half shell on the under-pressure side 2 rotor blade half shell on the over-pressure side 3 web 4 front edges 6 rear edges 7 belt 8 belt 9 web base 11 web base 21 outer position 22 inner position 23 high-temperature-resistant foam material 24 low-temperature-resistant foam material A areas with first, high-temperature-resistant foam materials B areas with second, low-temperature-resistant foam materials K adhesion areas L longitudinal direction