CN219774256U - Truss type wind turbine blade supporting girder and wind turbine blade - Google Patents

Abstract

The utility model belongs to the technical field of wind generating sets, and discloses a truss type wind turbine blade supporting girder and a wind turbine blade, wherein the supporting girder is of a multi-section structure and comprises a plurality of sections which are sequentially connected along the radial direction of the wind turbine, any section is of a quadrangular prism structure, and any section comprises four chord members which are arranged along the radial direction and web members which are connected between two adjacent chord members. The utility model sets the support girder to be a sectional structure, the manufacturing cost and the manufacturing difficulty are reduced by the support girder sections which can be manufactured independently, the transportation cost and the damage probability in the transportation process of the blade are reduced, the design of the blade is not limited by the manufacturing and transportation conditions, the sectional girder structure is convenient for replacement and maintenance operation, the service life of the blade is prolonged, meanwhile, the lattice type section structure is convenient for recycling, the whole service period of the fan is prolonged by phase change, and the load response stability in the operation process can be enhanced by connecting the sections of the quadrangular structure to form the lattice type support girder.

Description

Truss type wind turbine blade supporting girder and wind turbine blade

Technical Field

The utility model belongs to the technical field related to wind generating sets, and particularly relates to a truss type wind turbine blade supporting girder and a wind turbine blade.

Background

The wind generating set is used for converting wind energy into electric energy. With the development of wind turbines and the continuous improvement of the power generation, the diameters of the wind turbine blades are gradually increased, and higher requirements are provided for the overall benefits of manufacturing, transporting, maintaining and recycling the blades. Conventional blades currently used on wind turbines are typically formed by manually laying a composite layup of carbon or glass fibers and other materials in a full-scale mold, with the spar being positioned over the layup.

Conventional integral vanes suffer from a number of disadvantages: the large blade size causes high manufacturing cost, great difficulty, many limiting conditions and easy internal defect generation; the transportation cost is high, and the blades are easy to damage in the transportation process; the maintenance is difficult, the technical requirements on maintenance personnel are high, and the performance of the blade after maintenance is lost; after the blade is in service, the blade is difficult to effectively recycle. How to change the existing problems of the wind turbine blade becomes a problem to be solved urgently by the person skilled in the art and the related scientific researchers.

Disclosure of Invention

Aiming at the defects or improvement demands of the prior art, the utility model provides a truss type wind turbine blade supporting girder and a wind turbine blade, which solve the problems of high manufacturing and transportation difficulty, difficult maintenance and difficult effective recycling of the traditional blade.

In order to achieve the above object, according to one aspect of the present utility model, there is provided a truss type wind turbine blade support girder, the support girder having a multi-section structure, the support girder including a plurality of sections sequentially connected in a radial direction of a wind turbine, any one of the sections having a quadrangular prism structure, and any one of the sections including four chords disposed in the radial direction and web members connected between two adjacent chords.

According to the truss type wind turbine blade supporting main beam provided by the utility model, the web members are connected to the tail parts of the chords; any one of the segments further includes a chord reinforcement connected between the two chords, and a web reinforcement connected diagonally between the web members.

According to the truss type wind turbine blade supporting main beam provided by the utility model, the four chords of any section comprise two first chords oppositely arranged along a first direction and two second chords oppositely arranged along a second direction, and the first direction is perpendicular to the second direction;

the chord reinforcing rods comprise outer reinforcing rods and inner reinforcing rods, the outer reinforcing rods are connected between any one first chord member and the adjacent second chord member, and the inner reinforcing rods are connected between the two first chord members or between the two second chord members.

According to the truss type wind turbine blade supporting main beam provided by the utility model, the root parts of two outer reinforcing rods between any one first chord member and two adjacent second chord members are simultaneously connected with the first chord member or the tail parts are simultaneously connected with the first chord members.

According to the truss type wind turbine blade supporting main beam provided by the utility model, when the roots of the chord reinforcing rods are connected with the same chord, the roots of the chord reinforcing rods are connected with different parts of the same chord; when the tail parts of the chord reinforcing rods are connected with the same chord, the tail parts of the reinforcing rods are connected with different parts of the chord.

According to the truss type wind turbine blade supporting main beam provided by the utility model, the distance between the two first chords is different from the distance between the two second chords.

According to the truss type wind turbine blade supporting main beam provided by the utility model, the diameter of the chord member is the same as that of the web member reinforcing member, and the diameter of the chord member is larger than that of the chord member reinforcing member.

According to the truss type wind turbine blade supporting main beam provided by the utility model, a space is reserved between the root of the chord member reinforcing rod and the root of the chord member, and a space is reserved between the tail of the chord member reinforcing rod and the tail of the chord member.

According to another aspect of the present utility model there is provided a wind turbine blade comprising a support spar, the support spar being a truss wind turbine blade support spar as defined in any of the above.

The wind turbine blade provided by the utility model further comprises a skin, wherein the skin is arranged outside the section, close to the tail, of the support girder.

In general, compared with the prior art, the truss type wind turbine blade supporting girder and the wind turbine blade provided by the utility model have the technical scheme that the truss type wind turbine blade supporting girder and the wind turbine blade are designed by the utility model:

1. the supporting girder is of a sectional structure, each section can be manufactured and transported independently, manufacturing cost and manufacturing difficulty are reduced by the supporting girder sections which can be manufactured independently, quality of finished products is guaranteed, meanwhile, transportation cost of the blades and damage probability in the transportation process are reduced, the design of the blades is not limited by manufacturing and transportation conditions, maintenance difficulty of the blades is reduced by the sectional girder structure, replacement and maintenance operation are facilitated, service life of the blades is prolonged, recycling of the sectional structure of a lattice type is facilitated, overall service period of the fan is prolonged by phase change, and load response stability of the structural supporting girder of a quadrangular prism can be enhanced by connecting the sections of the structural supporting girder;

2. the chord member reinforcing rods and the web member reinforcing rods are arranged to strengthen the strength and the rigidity of the lattice type supporting main beam of the wind turbine blade, so that the supporting main beam can meet the use requirement of the blade in structural performance;

3. the provided blade uses the supporting girder to replace the area outside the tail of the traditional blade, only the skin is reserved at the tail, the lattice type supporting girder can reduce wind resistance in the area outside the tail, and the power generation efficiency of the blade is guaranteed at the tail skin.

Drawings

FIG. 1 is a first schematic view of a segment in a truss type wind turbine blade support spar provided by the present utility model;

FIG. 2 is a second schematic view of a segment in a truss type wind turbine blade support spar provided by the present utility model;

FIG. 3 is a schematic cross-sectional view of a segment in a truss type wind turbine blade support spar provided by the present utility model;

FIG. 4 is a schematic view of a wind turbine blade provided by the present utility model;

the same reference numbers are used throughout the drawings to reference like elements or structures, wherein:

1: supporting a main girder; 10: segments; 11: a first chord; 12: a second chord; 2: a web member; 31: an outer reinforcing rod; 32: an inner reinforcing rod; 4: web member reinforcing bars; 5: and (5) covering.

Detailed Description

The present utility model will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present utility model more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model. In addition, the technical features of the embodiments of the present utility model described below may be combined with each other as long as they do not collide with each other.

Referring to fig. 1 and 4, the present utility model provides a truss-type wind turbine blade support girder 1, where the support girder 1 has a multi-section structure, the support girder 1 includes a plurality of sections 10 sequentially connected along a radial direction of a wind turbine, any section 10 has a quadrangular prism structure, and any section 10 includes four chords disposed along the radial direction and a web member 2 connected between two adjacent chords.

The truss type wind turbine blade supporting main beam 1 is of a multi-section structure and is formed by sequentially connecting a plurality of sections 10, so that a sectional wind turbine blade structure is formed. The radial direction of the wind turbine, i.e. the direction of the blade from root to tail. Each section 10 of the support girder 1 can be manufactured and transported separately, avoiding the problem of limited manufacturing sites, and the transportation of the individual sections 10 is relatively simple, avoiding the problems of large transportation load, large length and difficult turning of the conventional blade. The conventional blade is difficult to develop in large scale due to difficult manufacture and transportation, and the sectional manufacture and transportation of the support girder 1 make the design of the blade not limited by the conditions of manufacture and transportation. And the integral support girder 1 is formed by the segments 10, so that the fault segment 10 can be replaced and repaired, the maintenance difficulty is reduced, and the integral service life of the blade is prolonged.

Further, each section 10 of the supporting girder 1 is a quadrangular frame structure, which is formed by four chord members to form sides of a quadrangular column, and then the web members 2 are connected between the adjacent chord members to connect the four chord members together, and to play a role of reinforcing the chord members. Referring to fig. 1, in the circumferential direction of the quadrangular prism, one web member 2 is connected between any two adjacent string members, and four web members 2 are connected between the four string members of any one section 10, thereby connecting the four string members. The supporting main beam 1 forms a wind turbine blade lattice type supporting main beam 1 section 10 by using a rod structure, and the recycling space of the rod structure is large and is convenient for recycling, so that the problems that the traditional blade is difficult to recycle after being abandoned and the material performance of recycled products is reduced are avoided, and the service cycle of a fan and the engineering benefit of the blade are improved by phase change. And the structure of any section 10 quadrangular prism of the supporting girder 1 can also strengthen the load response stability of the lattice type girder of the wind turbine blade during operation.

According to the truss type wind turbine blade supporting girder 1, the supporting girder 1 is provided to be of a sectional structure, each section 10 can be manufactured and transported independently, the manufacturing cost and the manufacturing difficulty of the supporting girder 1 sections 10 which can be manufactured independently are reduced, the quality of finished products is guaranteed, meanwhile, the transportation cost and the damage probability in the transportation process of the blade are reduced, the blade design is not limited by the manufacturing and transportation conditions, the maintenance difficulty of the blade is reduced by the sectional girder structure, the replacement and maintenance operation are facilitated, the service life of the blade is prolonged, meanwhile, the lattice type section 10 structure is convenient to recycle, the whole service period of the fan is prolonged by phase transformation, and the load response stability in the operation process can be enhanced by connecting the sections 10 of the quadrangular structure to form the lattice type supporting girder 1.

Further, referring to fig. 1, the web member 2 is connected to the tail of the chord member; any one of the segments 10 further comprises a chord reinforcement connected between two of the chords, and a web reinforcement 4 diagonally arranged between the web members 2. Chord reinforcement bars are connected between the two chord bars, and web reinforcement bars 4 may be connected between two opposite corners of the four web bars 2. The chord reinforcing rods and the web reinforcing rods 4 are arranged to strengthen the strength and rigidity of the lattice type supporting main beam 1 of the wind turbine blade, so that the supporting main beam 1 can meet the use requirement of the blade in terms of structural performance. The web member 2 is connected to the tail of the chord member, so that the chord member reinforcing member and the web member reinforcing member 4 can be conveniently arranged, and interference caused by positions is avoided.

In other embodiments, in any of the segments 10, the web member 2 may be attached to other portions of the chord, such as to the root of the chord or between the root and the tail; the web reinforcement 4 and the chord reinforcement can be flexibly installed according to the specific installation site of the web 2, and the specific installation site of the web 2 is not limited in order to prevent positional interference and to enhance rigidity and strength. The root part is the part close to the hub in the wind turbine, and the tail part is the part far away from the hub.

Further, the four chords of any one of the segments 10 include two first chords 11 disposed opposite in a first direction and two second chords 12 disposed opposite in a second direction, the first direction being perpendicular to the second direction. Any segment 10 may have a diamond shape in cross-section, as shown in fig. 1 and 3. The lattice type supporting main beam 1 formed by the quadrangular prism structure with the diamond-shaped section can strengthen the load response stability during operation.

Further, the chord reinforcing rod includes an outer reinforcing rod 31 and an inner reinforcing rod 32, the outer reinforcing rod 31 is connected between any one of the first chords 11 and the adjacent second chord 12, and the inner reinforcing rod 32 is connected between the two first chords 11 or between the two second chords 12. In the embodiment, the chord reinforcing rod connected between two chords is specifically divided into an outer reinforcing rod 31 and an inner reinforcing rod 32, wherein the outer reinforcing rod 31 is connected between the adjacent first chord 11 and second chord 12, and one outer reinforcing rod 31 is connected between any adjacent first chord 11 and second chord 12, namely four outer reinforcing rods 31 are arranged in total; while the inner reinforcing rod 32 is connected between the two first chords 11 or between the two second chords 12, one inner reinforcing rod 32 may be provided; therefore, the segments 10 can be firmly reinforced by fewer chord reinforcing rods, and the rigidity and the strength of the segments 10 can be ensured to meet the use requirement.

Further, the chord reinforcing rods are obliquely arranged relative to the radial direction; the root of the chord member reinforcing rod can be close to the root of the chord member, and the tail of the chord member reinforcing rod can be close to the tail of the chord member, so that the reinforcement effect can be better realized.

Further, the root portions of the two outer reinforcing rods 31 between any one of the first chords 11 and the adjacent two of the second chords 12 are simultaneously connected to the first chord 11 or the tail portions are simultaneously connected to the first chords 11.

Namely, there are two arrangements of the outer reinforcing rods 31 in this embodiment: first, referring to fig. 1, the outer reinforcement 31 connects two adjacent chords, the root portions of the outer reinforcement 31 are all disposed on the second chord 12, i.e., the horizontal chord in fig. 1, and the tail portions of the outer reinforcement 31 are all disposed on the first chord 11, i.e., the vertical chord in fig. 1. Second, referring to fig. 2, the outer reinforcement 31 connects two adjacent chords, the root portions of the outer reinforcement 31 are disposed on the first chord 11, i.e., the vertical chord in fig. 2, and the tail portions of the outer reinforcement 31 are disposed on the second chord 12, i.e., the horizontal chord in fig. 2. This arrangement makes the stage of supporting the main beam 1 form a lattice structure, and the arrangement of the inner reinforcing rods 32 and the outer reinforcing rods 31 can acquire optimal structural performance with the minimum number of arrangements, which is beneficial to ensuring the strength and rigidity of the main beam 1 and reducing the material consumption.

Further, referring to fig. 2, when the root portions of the two outer reinforcement bars 31 between any one of the first chords 11 and the adjacent two of the second chords 12 are simultaneously connected to the first chords 11, the inner reinforcement bar 32 may be connected between the two first chords 11. Referring to fig. 1, when the tail portions of two outer reinforcing rods 31 between any one of the first chords 11 and two adjacent second chords 12 are simultaneously connected to the first chords 11, an inner reinforcing rod 32 may be connected between the two second chords 12.

Further, the spacing between the two first chords 11 is different from the spacing between the two second chords 12. The diamond section structure is more uniform in stress in the section under the working condition of the fan blade, so that the load response stability of the supporting main beam 1 can be better enhanced during operation. The geometric shape of the diamond section is also more convenient for arranging the blade skin. The web reinforcement 4 may be connected between two opposing chords at a smaller distance.

Further, when the roots of the chord reinforcing rods are connected to the same chord, the roots of the chord reinforcing rods are connected to different positions of the same chord; the roots of the chord reinforcing rods are not connected to the same point, so that the connection firmness is improved. When the tail parts of the chord reinforcing rods are connected with the same chord, the tail parts of the reinforcing rods are connected with different parts of the chord. The tail parts of the chord reinforcing rods are not connected to the same point, so that the connection firmness is improved.

Further, for any segment 10, the web members 2 connected between the two chord members lie on the same plane, and the plane is perpendicular to the radial direction. Web members 2 and web member reinforcement members 4 lie in the same plane perpendicular to the radial direction. The root parts of the plurality of chord bar reinforcing rods are positioned on the same plane vertical to the radial direction; the tail parts of the string reinforcing rods are also positioned on the same plane perpendicular to the radial direction.

Further, a space is provided between the root of the chord reinforcement and the root of the chord, and a space is provided between the tail of the chord reinforcement and the tail of the chord. Facilitating the connection between adjacent segments 10. There may be a spacing between the tail of the chord reinforcement and the web member 2.

Further, for any one segment 10, the diameter of the chord member, the diameter of the web member 2, is the same as the diameter of the web member reinforcement 4, the diameter of the chord member being greater than the diameter of the chord member reinforcement. That is, the segmented inner chord, web member 2 and web member reinforcement 4 are the same size, and the outer reinforcement 31 and inner reinforcement 32 are the same size. The chord cross-sectional dimension is greater than the chord stiffener cross-sectional dimension.

Further, the chord member and the web member 2, the web member 2 and the web member reinforcement member 4, and the chord member reinforcement member may be connected by welding, respectively. The adjacent segments 10 may be joined by welding, for example, the adjacent segments 10 may be joined by chord-wise welding. In other embodiments, the connection may be other, and the purpose of the connection between the chord and the web member 2, between the web member 2 and the web reinforcement 4, between the chord and the web reinforcement, and between the adjacent segments 10 is not specifically limited.

Further, the utility model also provides a wind turbine blade, which comprises a supporting girder 1, wherein the supporting girder 1 is the truss type wind turbine blade supporting girder 1.

Further, the wind turbine blade provided by the utility model further comprises a skin 5, wherein the skin 5 is arranged outside the section 10 of the support girder 1 near the tail. In the embodiment, the traditional wind turbine blade has the advantages that the tail part provides most of wind energy capturing effect during operation, and the rest part has low efficiency and is subjected to a large amount of wind resistance, so that the operation benefit of the blade is reduced. Based on the above, the wind turbine blade provided by the utility model uses the lattice type supporting girder 1 of the wind turbine blade to replace the area outside the tail of the traditional blade, and only the tail reserved skin 5 is arranged, so that the wind resistance of the area outside the tail can be reduced by the lattice type supporting girder 1, and the power generation efficiency of the blade is ensured by the tail skin 5, as shown in fig. 4. The skin 5 is arranged outside at least one section 10 supporting the tail of the girder 1.

Furthermore, the wind turbine blade provided by the utility model uses metal to manufacture the supporting main beam 1, and only carries out the blade skin at the tail part, so that the use of composite materials such as carbon fiber or glass fiber can be reduced, and the integral recoverability of the blade can be enhanced.

Furthermore, in order to solve the defects existing in the use process of the existing wind turbine blade, the utility model provides the diamond lattice type supporting girder 1 of the segmented wind turbine blade and the structural arrangement form thereof, so that the wind turbine blade girder which is simple to manufacture, stable in transportation, easy to maintain and convenient to recycle is manufactured.

The segments 10 of the lattice type supporting main beam 1 of the wind turbine blade are of a quadrangular prism structure, and each segment, namely the segments 10, is provided with four chords, a plurality of web members 2 and reinforcing rods. The chords are uniformly distributed on four vertexes of the sectional diamond-shaped section, and the chords are divided into a horizontal chord member, namely a second chord member 12, and a vertical chord member, namely a first chord member 11, wherein the distance between the two horizontal chord members is smaller than that between the two vertical chord members. The individual segments are interconnected between the inner chords using web members 2 and chord reinforcement members, the different segments being interconnected by welded chords. The web members 2 are distributed at the ends of the segments, i.e. the tail parts, and connect the ends of the four chord members together. Web reinforcement 4 is arranged at the end of the segments connecting the horizontal chord tails.

Further, referring to FIG. 1, four outer reinforcing rods 31 may each connect a horizontal chord root with an adjacent vertical chord tail. The inner reinforcement 32 connects the root and tail of the two horizontal chords. Four web members 2 are distributed at the tail parts of the sections, and each web member 2 is respectively connected with the tail parts of the adjacent horizontal chords and the tail parts of the vertical chords. The web member reinforcing rods 4 are distributed at the tail parts of the sections and are connected with the tail parts of the two horizontal chords. The root parts of the outer reinforcing rod 31 and the inner reinforcing rod 32 are all distributed on the same vertical plane, the tail parts of the outer reinforcing rod 31 and the inner reinforcing rod 32 are all distributed on the same vertical plane, and the web members 2 and 4 are all distributed on the same vertical plane. The vertical planes of the web members 2 and 4 are staggered with the vertical plane of the tail of the outer reinforcing member 31 and the tail of the inner reinforcing member 32.

In the arrangement of fig. 1, the roots of two adjacent outer reinforcing rods 31 and the roots of two adjacent inner reinforcing rods 32 are distributed in a staggered manner on the same horizontal chord, namely, are not arranged in a common point, and the tails of two adjacent outer reinforcing rods 31 are distributed in a staggered manner on the same vertical chord, namely, are not arranged in a common point. In the arrangement of fig. 2, the root parts of two adjacent outer reinforcing rods 31 and the root parts of the inner reinforcing rods 32 are distributed in a staggered manner on the same vertical chord, namely, are not arranged in a common point, and the tail parts of two adjacent outer reinforcing rods 31 are distributed in a staggered manner on the same horizontal chord, namely, are not arranged in a common point. The single segmented inner chord member, the web member 2 and the reinforcing rod are connected in a welding mode. The description of horizontal and vertical directions in the above description, that is, directions based on corresponding illustrated directions, is for convenience of direction understanding, and does not limit the setting directions in practical applications.

Further, the chord, web member 2, chord stiffener and web stiffener 4 may be steel pipes.

The utility model has the advantages that: each section 10 of the main girder is composed of circular metal steel pipes with different sizes, and the strength, rigidity and stability of each direction are small in difference, and the structural performance of the main girder is similar to that of a traditional blade made of composite materials. The wind turbine blade lattice type supporting girder 1 is used for replacing the area except the tail part of the traditional blade, the girder segments 10 can be manufactured independently, the problem of limited manufacturing sites is avoided, and meanwhile, the structural defects possibly occurring in manual manufacturing are reduced; the single segment 10 is relatively simple to transport, and the problems of large transportation load, large length and difficult turning of the traditional blade are avoided; the conventional blade is difficult to develop in large scale due to difficult manufacture and transportation, and the sectional manufacture and transportation of the support girder 1 make the design of the blade not limited by the conditions of manufacture and transportation. The integral beam is composed of the metal subsection 10, so that the fault subsection can be replaced and repaired, the maintenance difficulty is reduced, and the integral service life of the blade is prolonged; the lattice type supporting girder 1 segment 10 of the wind turbine blade is manufactured by using metal, so that the problems that the traditional blade is difficult to recover after being abandoned and the material performance of recovered products is reduced are solved, and the service cycle of the wind turbine and the engineering benefit of the blade are improved by phase change. The cross section size of the chord member is larger than that of the chord member reinforcing rod, so that the whole strength and rigidity are ensured, and meanwhile, the use of materials is reduced. The chords in segment 10 are disposed at the vertices of the diamond with a horizontal distance less than a vertical distance. The strength and rigidity of the segment 10 after loading are enhanced, and the structural response anisotropy after loading in different directions is reduced, so that the segment is more suitable for the loading condition of the fan blade. The supporting main beam 1 and the blade provided by the utility model also have the advantages of simple and compact structure and low manufacturing cost.

It will be readily appreciated by those skilled in the art that the foregoing description is merely a preferred embodiment of the utility model and is not intended to limit the utility model, but any modifications, equivalents, improvements or alternatives falling within the spirit and principles of the utility model are intended to be included within the scope of the utility model.

Claims (10)

1. The truss type wind turbine blade supporting main beam is characterized in that the supporting main beam (1) is of a multi-section structure, the supporting main beam (1) comprises a plurality of sections (10) which are sequentially connected along the radial direction of a wind turbine, any section (10) is of a quadrangular prism structure, and any section (10) comprises four chord members which are arranged along the radial direction and web members (2) connected between the adjacent chord members.

2. Truss-like wind turbine blade support girder according to claim 1, characterized in that the web members (2) are connected to the tail of the chord members; any one of the segments (10) further comprises a chord reinforcement connected between two of the chords, and a web reinforcement (4) diagonally arranged between the web members (2).

3. Truss-like wind turbine blade support girder according to claim 2, wherein the four chords of any one of said segments (10) comprise two first chords (11) arranged opposite in a first direction and two second chords (12) arranged opposite in a second direction, said first direction and said second direction being perpendicular;

the chord reinforcing rod comprises an outer reinforcing rod (31) and an inner reinforcing rod (32), wherein the outer reinforcing rod (31) is connected between any one first chord (11) and the adjacent second chord (12), and the inner reinforcing rod (32) is connected between the two first chords (11) or between the two second chords (12).

4. A truss-like wind turbine blade support girder according to claim 3, wherein the root portions of two outer stiffening rods (31) between any one of said first chords (11) and two adjacent second chords (12) are connected to said first chord (11) at the same time or the tail portions are connected to said first chord (11) at the same time.

5. The truss type wind turbine blade support spar of any of claims 2-4, wherein when the root portions of a plurality of said chord stiffeners are connected to a same said chord, the root portions of a plurality of said chord stiffeners are connected to different portions of the same said chord; when the tail parts of the chord reinforcing rods are connected with the same chord, the tail parts of the reinforcing rods are connected with different parts of the chord.

6. A truss-like wind turbine blade support girder according to claim 3, characterised in that the spacing between two of said first chords (11) is different from the spacing between two of said second chords (12).

7. Truss type wind turbine blade support girder according to any of the claims 2-4, wherein the diameter of the chord members, the diameter of the web members (2) being the same as the diameter of the web reinforcement members (4), the diameter of the chord members being larger than the diameter of the chord reinforcement members.

8. The truss type wind turbine blade support spar of any of claims 2-4, wherein there is a spacing between the root of the chord stiffener and the root of the chord, and a spacing between the tail of the chord stiffener and the tail of the chord.

9. A wind turbine blade, comprising a support girder (1), the support girder (1) being a truss-like wind turbine blade support girder according to any of the preceding claims 1-8.

10. A wind turbine blade according to claim 9, further comprising a skin (5), said skin (5) being provided outside said section of said support spar (1) near the tail.