A hollow skeleton structure of a wind turbine blade

Abstract

A hollow skeleton structure of a wind turbine blade, comprising a blade stem and a blade frame connected to the blade stem; the blade frame and / or the blade stem are formed by interconnecting a plurality of hollow tubes. On the one hand, the present invention can not only greatly increase the contact area with the tube body, thereby increasing the connection strength; and after the first corrugated screw seat is pressed and formed by the plate body, it is a bent structure, which can increase its own strength by bending, so that the plate thickness of the first corrugated screw seat can be made thinner, and the mechanical properties of the structure are better; on the other hand, the longitudinal rods, horizontal trusses and the blade stem can be quickly installed and disassembled, and can be reused after disassembly.

Description

Technical Field

[0001] The invention relates to a wind turbine blade skeleton, in particular to a hollow skeleton structure of a wind turbine blade. Background Art

[0002] The existing wind power generation system is usually connected to the hub by a tower, and then the hub is connected to the wind turbine blades. Most of the existing towers are truss structures made of hollow tubes, while wind turbine blades are usually made of materials such as fiberglass, and the blades are formed by mold processing. On the one hand, the manufacturing process and mold processing costs are high, and the blade shell needs to be designed as a curved surface, which is difficult to design; on the other hand, the fiberglass and other materials are heavy and the size cannot be designed larger, that is, the larger the volume of the blade, the heavier the blade made of fiberglass. The existing blade skeleton usually sets a conical tube in the inner cavity of the blade as a leaf stem, or uses multiple spaced webs as a leaf stem to increase the strength of the blade. However, these two leaf stem structures are still low in strength when the blade encounters strong winds, which can easily cause the blade to break.

[0003] In addition, the present invention has made a completely new improvement to the blades, and the blade body is designed into a sash structure, which can be opened and closed under the action of wind. CN201120352480X discloses a sash-shaped blade combined wind wheel for a vertical axis wind turbine, which also designs a sash blade that can be opened and closed, but the skeleton part is not provided with a blade stem, but the frame is directly installed on the main shaft of the wind wheel. The strength of the main shaft of the wind wheel cannot be guaranteed under the action of strong winds, and the frame is a horizontal main beam, and it is not specified whether it is a solid rod or a hollow rod. Therefore, there is no technical inspiration for the present invention, and its structural strength is also poor. Once encountering strong winds, it is easy to break, and its bending, torsion and fatigue resistance are poor. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art and provide a hollow skeleton structure which has high bending and torsional strength, good fatigue resistance and can be applied to wind turbine blades of any wind force.

[0005] The technical solution of the present invention is: a hollow skeleton structure of a wind turbine blade, comprising a blade stem and a blade frame connected to the blade stem; the blade frame and / or the blade stem are formed by a plurality of hollow tubes connected to each other.

[0006] Furthermore, the leaf frame includes a plurality of horizontal trusses extending horizontally along both sides of the leaf stem and arranged at intervals, and the horizontal trusses include cross bars, diagonal bars and support bars arranged between the cross bars and the diagonal bars.

[0007] Furthermore, the leaf frame also includes a longitudinal rod connected to the horizontal truss; the longitudinal rod, the horizontal truss and the leaf stem are connected to form a whole.

[0008] Furthermore, the longitudinal bars are provided between the cross bars of adjacent horizontal trusses, between the diagonal bars and on the outer sides of all the horizontal trusses.

[0009] Furthermore, one end of the leaf stem is connected to the hub; both ends of the leaf stem extend along the leaf frame.

[0010] Furthermore, the cross-sectional shape of the leaf stem is an N-gon, where N≥4.

[0011] Furthermore, the cross bars and diagonal bars of the horizontal truss are connected to the leaf stem part, and a bent corrugated screw seat is provided on the hollow tube body of the leaf stem part. The corrugated screw seat includes a fitting surface and a connecting surface. The fitting surface is adaptively connected to the tube body. Flange plates are provided on the cross bars and diagonal bars, and are connected and fixed by bolts passing through the flange plate and the connecting surface of the corrugated screw seat.

[0012] Furthermore, the leaf stem portion includes a leaf stem main body and a leaf stem tip portion, the leaf stem tip portion is a polygonal cone structure that gradually forms a tip, and the leaf stem tip portion and the leaf stem main body are flange-connected; and the outer diameter of the hollow tube of the leaf stem tip portion is smaller than the outer diameter of the hollow tube of the leaf stem main body.

[0013] Further, the size of the leaf frame connected to the tip of the leaf stem is smaller than the size of the leaf frame connected to the main body of the leaf stem.

[0014] Furthermore, ropes are connected between the leaf stem and the leaf frame and in the longitudinal direction of the leaf frame to form a hexagonal rope structure, and the ropes are in a tensioned state to form a whole with the leaf stem and the leaf frame.

[0015] Beneficial effects of the present invention:

[0016] (1) The blade skeleton is designed to achieve maximum strength with minimum material and lightest weight, and has strong bending and torsional strength both horizontally and vertically, can withstand strong winds, and is not easy to break;

[0017] (2) By designing the connection structure between the leaf stem and the leaf frame, on the one hand, not only can the contact area with the tube body be greatly increased, thereby improving the connection strength; and after the first corrugated screw seat is pressed and formed by the plate body, it itself is a bent structure, which can improve its own strength by bending, so that the plate thickness of the first corrugated screw seat can be made thinner, and the mechanical properties of the structure are better; on the other hand, the longitudinal rod, the horizontal truss and the leaf stem can be quickly installed and disassembled, and can be reused after disassembly;

[0018] (3) By setting a tightened rope for the entire frame, the stress on the frame is borne by the rope, and the rope is subjected to unidirectional force, thereby eliminating the fatigue effect of the positive and negative forces on the frame, greatly improving the service life of the frame. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of the skeleton structure of Example 1 of the present invention;

[0020] Figure 2 It is a schematic diagram of the reverse structure of the skeleton of Example 1 of the present invention;

[0021] Figure 3 This is a schematic diagram of the connection structure between the leaf stem main body and the leaf stem tip in Example 1 of the present invention;

[0022] Figure 4 Schematic diagram of the connection structure between the horizontal bar and the vertical bar in Example 1 of the present invention;

[0023] Figure 5 This is a schematic diagram of the connection structure between the cross bar and the leaf stem of Example 1 of the present invention;

[0024] Figure 6 This is a schematic diagram of the connection structure between the horizontal truss and the longitudinal rod in Example 1 of the present invention;

[0025] Figure 7 2 is a schematic structural diagram of a first compression screw seat according to Embodiment 1 of the present invention;

[0026] Figure 8 yes Figure 5 An enlarged schematic diagram of the structure of the embodiment 1 in which the cross bar and the leaf stem are connected via the first compression screw seat;

[0027] Fig. 9 yes Figure 6 The illustrated embodiment 1 is an enlarged schematic diagram of the structure in which the cross bar and the longitudinal bar are connected via the second pressed screw seat.

[0028] Description of the accompanying drawings:

[0029] 1. Leaf stem; 2. Leaf frame; 3. Hollow tube; 4. First corrugated screw seat; 5. Second corrugated screw seat; 6. Flange plate; 7. Rope; 11. Leaf stem body; 12. Leaf stem tip; 21. Horizontal truss; 22. Longitudinal rod; 41. Fitting surface; 42. Connecting surface; 43. Connecting hole; 44. Bending edge; 45. Prefabricated nut; 111. Column; 112. Rod body; 211. Crossbar; 212. Diagonal rod; 213. Support rod. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Example 1

[0032] like Figure 1 and Figure 2As shown: a hollow skeleton structure of a wind turbine blade, including a blade stem 1 and a blade frame 2 connected to the blade stem 1; the blade frame 2 and the blade stem 1 are both formed by a plurality of hollow tubes 3 connected to each other.

[0033] The above scheme has the following advantages: the leaf stem and the leaf frame are connected by a hollow tube, which is light in weight and saves materials; on the other hand, since the leaf stem and the leaf frame are used to bear the load, especially when used for wind power generation, once encountering the impact of strong wind, it is more necessary to design the leaf stem and the leaf frame into a skeleton structure with high bending and torsional strength. The present embodiment adopts a hollow tube, and more preferably a hollow tube with a circular cross section, in order to obtain the maximum strength with the least material and the lightest weight. The design concept of the inventor is: combined with the reeds in nature, since the reed stem is hollow, and the reeds have to experience wind, frost, rain and snow in nature, especially wind, which is the most tested strength of the reed stem. If it is blown down by the wind, the reed cannot continue to survive. In the evolution process of the reed, the hollow reed has a strong survival ability and gradually becomes the dominant species in the reed. Therefore, the inventor thinks of using the same principle to design the leaf skeleton and the leaf frame into a hollow tube structure, which can maintain a certain bending and torsional strength even in strong winds.

[0034] Specifically, in the present embodiment, the blade stem 1 adopts a truss structure, and the truss is composed of a hollow tube 3, the cross section of which has good compression and bending and torsional bearing capacity and large rigidity, and is not easily broken by strong wind during the operation of the wind turbine blade. The cross-sectional shape of the blade stem of the present embodiment is an N-gon, N≥4. The inventors found during the experiment that if it is designed as a triangular truss, the bending and torsional performance of the end of the blade stem connected to the hub is poor and it is easy to break. Therefore, it is designed as a polygonal structure with N≥4. The present embodiment is preferably designed as a quadrilateral, which can not only meet the bending and torsional strength requirements, but also save materials and make the structural design simpler.

[0035] like Figure 3 As shown: In this embodiment, the truss structure of the leaf stem portion 1 includes four columns 111 and transverse and oblique rods 112 arranged between the columns. The column can be composed of multiple sections or one section. The column and other rods are directly welded into one body to form a truss. The leaf stem portion 1 includes a leaf stem body 11 and a leaf stem tip 12, and the leaf stem body 11 and the leaf stem tip 12 are both truss structures.

[0036] The leaf stem body 11 can be a cone structure with gradually decreasing size, or a structure with the same size in each cross section. The leaf stem body can be a segmented structure or an integral structure. If a segmented structure is adopted, multiple leaf stem bodies are connected to each other through flanges to form an integral structure. The segmented structure is designed to facilitate the combination of leaf stems of different lengths.

[0037] The tip 12 of the leaf stem is a quadrilateral cone structure that gradually forms a tip, that is, the main cone 11 and the tip 12 of the leaf stem are both prism structures, but the top of the tip of the leaf stem is more pointed. Flanges are provided on the column of the tip of the leaf stem and the main body of the leaf stem, and the two are connected by flange threads. Among them, the outer diameter of the hollow tube of the tip 12 of the leaf stem is smaller than the outer diameter of the hollow tube of the main body 11 of the leaf stem. Since the existing blades are designed as tip structures, the two ends of the leaf stem 1 of the present invention extend along the leaf frame 2, the blades are installed on the leaf frame, and the blades are window sash structures that can be rotated around the leaf frame. When a certain wind force is reached, the window sash can be blown open. Therefore, the leaf stem of the present invention is exposed to the outside. In the design of the leaf stem, if the leaf stem is a cone with a gradually decreasing size, the end connected to the hub has the greatest strength and the largest size, and the size gradually decreases during the transition to the tip of the leaf stem.

[0038] The leaf stem portion of this embodiment has the following advantages: (1) it achieves maximum strength with the lightest weight; and (2) by separately arranging the leaf stem tip and the leaf stem body and connecting them through a flange, the strength of the leaf stem portion can be improved, it is not easy to break, and it is easier to design compared to an overall arrangement.

[0039] In this embodiment, the leaf frame 2 includes a plurality of horizontal trusses 21 arranged at intervals and extending horizontally along both sides of the leaf stem 1, and longitudinal bars 22 connected to the horizontal trusses. The horizontal trusses 21 include a crossbar 211, an oblique bar 212, and a support bar 213 disposed between the crossbar and the oblique bar. Specifically, each horizontal truss 21 includes two crossbars 211, extending along both sides of the leaf stem, the oblique bar is connected between the crossbar and the leaf stem, and a plurality of support bars are connected between the crossbar and the oblique bar, and the crossbar, the oblique bar and the support bar are all hollow tubes 3.

[0040] In this embodiment, a plurality of horizontal trusses 21 arranged at intervals are connected to the leaf stem body 11 of the leaf stem, and a certain length is reserved at both ends of the main cone 11, the end with the largest size is connected to the hub, and the end with the smallest size is connected to the leaf stem tip 12. Horizontal trusses 21 are also extended from both ends of the leaf stem tip, and the length of the horizontal trusses is less than the length of the horizontal trusses connected to the main cone, so that the force between the leaf stem and the leaf frame is uniform.

[0041] In this embodiment, the longitudinal rod 22 is also a hollow tube. Specifically, longitudinal rods 22 are connected between the cross bars and cross bars of adjacent horizontal trusses 21, between the diagonal rods and diagonal rods, and on the outer sides of all horizontal trusses 21 on the leaf stem body 11. Among them, the outer sides of all horizontal trusses 21 on the leaf stem body 11 are connected to a longitudinal rod 22 to form a main frame structure; the horizontal trusses 21 located at the tip 12 of the leaf stem can only connect the cross bars 211 to the longitudinal rod 22, and the diagonal rods may not be connected. By providing the longitudinal rod 22, the bending and torsional strength of the leaf frame can be improved. The longitudinal rod 22, the horizontal trusses 21 and the leaf stem 1 are connected to form a whole, which can greatly improve the strength of the overall skeleton.

[0042] In this embodiment, the hollow tubes 3 of the leaf stem 1 can be directly welded to form an integral truss structure, and the horizontal truss 21 can also be directly welded to form an integral truss structure between the crossbars 211, the diagonal bars 212 and the support bars 213. The connection between the horizontal truss 21 and the leaf stem 1 and the connection between the longitudinal bars 22 and the horizontal truss 21 are preferably threaded, which can achieve quick installation and removal, improve utilization, and have high bolt connection strength.

[0043] like Figure 5 , Figure 7 and Figure 8 As shown: In this embodiment, the horizontal bar 211 and the diagonal bar 212 of the horizontal truss 21 are respectively connected to the adjacent columns 111 of the leaf stem 1. A bent first press-formed screw seat 4 is provided on the tube body of the column 111, and the first press-formed screw seat 4 includes a fitting surface 41 adapted to the tube body and a connecting surface 42 extending along the fitting surface.

[0044] Among them, the fitting surface 41 is an arc-shaped surface, which is compatible with the tube body. The two ends of the fitting surface 41 of the first corrugated screw seat 4 are bent to form a connecting surface 42, and a connecting hole 43 is provided on the connecting surface 42. After the plate body of the first corrugated screw seat 4 is pressed to form the fitting surface 41 and the connecting surface 42, it continues to bend downward along the side of the connecting surface to form a bending edge 44. The lower part of the bending edge 44 is fitted and connected with the tube body, that is, the fitting surface 41 and the bending edge 44 of the first corrugated screw seat 4 are welded and fixed to the tube body. In this way, the contact area can be greatly increased, the force is stable, and the first corrugated screw seat 4 is bent multiple times, which greatly improves its own strength, and the plate thickness of the first corrugated screw seat 4 can be designed to be thinner. A prefabricated nut 45 is provided below the connecting hole of the first corrugated screw seat 4, and the bolt passes through the flange plate 6 and the connecting hole of the first corrugated bolt 4 through a gasket and is threadedly fixed to the prefabricated nut 45.

[0045] like Figure 4As shown: In this embodiment, a first pressed screw seat 4 is also provided on the tube body of each cross bar 211 of all horizontal trusses on the leaf stem body and on the tube body of the outermost longitudinal bar 22, so that the end of the cross bar of the horizontal truss is threadedly connected to the tube body of the outer longitudinal bar, and the end of the longitudinal bar is also threadedly connected to the tube body of the cross bar, so that the outer sides of all horizontal trusses 21 are connected to a longitudinal bar 22 to form a main frame structure.

[0046] like Figure 6 and Fig. 9 As shown: the connection between the longitudinal rod 22 and the adjacent transverse rod 211 and the adjacent diagonal rod 212 is connected by the second corrugated screw seat 5, that is, the second corrugated screw seat is set on the tube body of the transverse rod and the diagonal rod. Since the longitudinal rod connected between the adjacent transverse rods or diagonal rods is not the main force-bearing structure, the difference between the second corrugated screw seat here and the first corrugated screw seat is that no bending edge is set, that is, the second corrugated screw seat includes a fitting surface that matches the tube body of the transverse rod or diagonal rod and a connecting surface extending along the fitting surface. The connecting surface is a horizontal surface and does not need to be bent. A flange plate is provided on the longitudinal rod 22, and the bolt connection method is the same as the first corrugated screw seat mentioned above, which will not be described in detail here.

[0047] In summary, this embodiment achieves maximum strength with minimum material and lightest weight by designing the blade skeleton, and has strong bending and torsional strength both horizontally and vertically, can withstand strong winds, and is not easily broken.

[0048] This embodiment designs the connection structure between the leaf stem and the leaf frame, which not only greatly increases the contact area with the tube body and thus improves the connection strength; moreover, after the first corrugated screw seat is pressed and formed by the plate body, it itself has a bent structure, which can improve its own strength by bending, so that the plate thickness of the first corrugated screw seat can be made thinner and the mechanical properties of the structure are better; on the other hand, the longitudinal rods, horizontal trusses and leaf stems can be quickly installed and disassembled, and can be reused after disassembly.

[0049] Example 2

[0050] like Figure 1 and Figure 2 As shown: On the basis of Example 1, ropes 7 are connected between the leaf stem 1 and the leaf frame 2 and in the longitudinal direction of the leaf frame 2 to form a hexagonal rope structure, and the ropes 7 are in a tensioned state to form a whole with the leaf stem 1 and the leaf frame 2.

[0051] Specifically, the rope 7 is a steel wire rope; there are six ropes 7, namely, two ropes are arranged between the end of the leaf stem main body 11 and the cross bar 211 of the horizontal truss close to the end, two ropes are arranged between the tip of the leaf stem tip 12 and the cross bar of the horizontal truss close to the tip, and two ropes are arranged in the direction of the longitudinal rod commonly connected to the outer sides of all horizontal trusses connected to the leaf stem main body. The six ropes are respectively connected to the connecting parts on the leaf stem and the leaf frame to form a hexagonal structure in a tensioned state.

[0052] In this embodiment, the entire frame is connected to ropes, and the ropes are in a tensioned state, so that the ropes tension the frame through the connecting parts. In this way, the stress on the frame is borne by the ropes, and the ropes are subjected to unidirectional force, thereby eliminating the fatigue effect of the forward and reverse forces on the frame, and greatly improving the service life of the frame.

Claims

1. A hollow skeleton structure of a wind turbine blade, characterized in that: It includes a leaf stem portion and a leaf frame connected to the leaf stem portion; it is characterized in that: the leaf frame and the leaf stem portion are formed by a plurality of hollow tubes connected to each other; the leaf frame includes a plurality of horizontal trusses horizontally extending along both sides of the leaf stem portion and arranged at intervals, and longitudinal rods connected to the horizontal trusses; the longitudinal rods, horizontal trusses and the leaf stem portion are connected to form a whole; the horizontal trusses include cross bars, oblique rods and supporting rods arranged between the cross bars and the oblique rods; the leaf frame is used to install blades, and the blades are window sash structures that can be rotated and connected around the leaf frame, and the window sashes can be blown open when a certain wind force is reached; the leaf stem portion is a truss structure composed of hollow tubes, and the cross-sectional shape of the leaf stem portion is an N-gon, N≥4; one end of the leaf stem portion is connected to a hub.

2. The hollow skeleton structure of a wind turbine blade according to claim 1, characterized in that: The longitudinal bars are arranged between the cross bars and between the diagonal bars of adjacent horizontal trusses and on the outer sides of all the horizontal trusses.

3. The hollow skeleton structure of a wind turbine blade according to claim 1, characterized in that: Both ends of the leaf stem extend along the leaf frame.

4. The hollow skeleton structure of a wind turbine blade according to claim 1, characterized in that: The cross bars and diagonal bars of the horizontal truss are connected to the leaf stem part. The hollow tube body of the leaf stem part is provided with a bent corrugated screw seat. The corrugated screw seat includes a fitting surface and a connecting surface. The fitting surface is adaptively connected to the tube body. Flange plates are provided on the cross bars and diagonal bars, and are connected and fixed by bolts passing through the flange plate and the connecting surface of the corrugated screw seat.

5. The hollow skeleton structure of a wind turbine blade according to claim 1, characterized in that: The leaf stem portion includes a leaf stem main body and a leaf stem tip portion, the leaf stem tip portion is a polygonal cone structure with a gradually formed tip, and the leaf stem tip portion and the leaf stem main body are flange-connected; and the outer diameter of the hollow tube of the leaf stem tip portion is smaller than the outer diameter of the hollow tube of the leaf stem main body.

6. The hollow skeleton structure of a wind turbine blade according to claim 5, characterized in that: The size of the leaf frame connected to the tip of the leaf stem is smaller than the size of the leaf frame connected to the main body of the leaf stem.

7. The hollow skeleton structure of a wind turbine blade according to claim 1, characterized in that: Ropes are connected between the leaf stem and the leaf frame and in the longitudinal direction of the leaf frame to form a hexagonal rope structure. The ropes are in a tensioned state and form a whole with the leaf stem and the leaf frame.

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