Lattice type tower and wind turbine generator

Abstract

The invention discloses a lattice type tower and a wind turbine generator. The supporting frame is composed of at least three main supporting legs, a first supporting piece and a second supporting piece. Between any two adjacent main supporting legs, any first supporting piece is intersected and connected with at least two second supporting pieces at the middle part; meanwhile, the middle of any second supporting piece is intersected and connected with at least two first supporting pieces. The two sets of supporting pieces can form a complete metal structure through two schemes, the reliability of the structure is improved, and the possibility of connection failure or the problem of large maintenance workload in welding and bolt connection is reduced. The connection structure of all the nodes is greatly simplified, the supporting pieces are matched with the main supporting legs, the torsional rigidity of the tower is improved, and meanwhile the material cost and the manufacturing cost can be controlled. And meanwhile, the first supporting piece and the second supporting piece are mutually connected for multiple times in the middle, and the torsion resistance, the bending resistance and the like of the lattice type tower are enhanced through mutual supporting.

Description

Technical Field

[0001] The present invention belongs to the technical field of wind power generation, and particularly relates to a lattice tower and a wind turbine unit. Background Art

[0002] Wind power is the most valuable power generation method for large-scale development and commercial development prospects in the field of renewable energy. The exploitable wind energy is widely distributed and has huge reserves globally.

[0003] The tower is an important component in a wind turbine unit. It supports the nacelle and impeller parts of the wind turbine unit at a relatively high position, ensuring a safe distance between the tip of the impeller and the ground when the impeller rotates. At the same time, due to the wind shear effect, the impeller can also obtain a higher wind speed and much more electrical energy output at a higher position.

[0004] Another more important function of the tower is to transfer the loads formed in the nacelle and impeller to the foundation and the ground. Conventional wind turbine towers adopt the structural form of a steel cylinder. In addition, there is also a technical solution of a lattice tower. The greatest advantage of the lattice tower is that the amount of material used is less than that of the steel cylinder tower, so that the total cost of the tower part of the wind turbine unit can be reduced.

[0005] The lattice tower in the prior art is composed of several chord members and web members, and the two ends of the web members are connected to adjacent chord members. And in the existing technology, the structural form of the lattice tower has no obvious difference from the classical space truss or lattice structure form. This way of connecting the compression web members and tension web members at the ends through nodes or connecting them to the chord members is widely used in high-voltage power towers, signal towers, and the civil engineering industry (such as tower cranes). In fact, in these application fields, the lattice structure mainly needs to provide appropriate bending resistance to cope with the action of external loads (including gravity loads, wind loads, etc.). Therefore, in terms of bending stiffness, the lattice tower is not inferior to the steel round tower. However, the lattice tower or the lattice structure has an obvious disadvantage - relatively poor torsional resistance. And the wind turbine unit is one of the few engineering application examples in the world that will bring torsional direction loads to the lattice tower, and its magnitude cannot be ignored.

[0006] Therefore, the insufficient torsional resistance of the lattice tower has become an important factor that cannot be ignored in tower selection, and it is also one of the disadvantages of the lattice tower in the application in the field of wind power generation. When the wind turbine unit adopts the horizontal axis form, the torsional direction load borne by the lattice tower mainly comes from the additional combined moment of the hub caused by the load imbalance of multiple blades during the operation of the unit. The magnitude of this additional combined moment is huge. When the wind turbine unit adopts the vertical axis form, the torsional direction load borne by the lattice tower mainly comes from the reverse moment (Newton's third law) caused by the electromagnetic torque when the vertical axis wind turbine generator generates electric energy. The magnitude of this torque is also not negligible.

[0007] To make up for the insufficient torsional resistance of the lattice tower, the existing technical solutions have to use higher-specification web members (larger cross-sections or thicker wall thicknesses). On the one hand, it improves the torsional stiffness of the entire tower, and on the other hand, it also meets the regulations regarding stress ratio and slenderness ratio in the steel structure design standards. However, this approach will inevitably lead to an increase in steel consumption and material costs, thereby reducing the advantages of using lattice towers, which also runs counter to the original intention of choosing lattice towers instead of steel cylindrical towers to reduce the total cost.

[0008] In addition, the lattice tower does not have a continuous material distribution. Therefore, during the manufacturing process, it involves a large number of connections between chord members and web members, and even the staggered connections between web members, that is, the node connections in the steel structure. In many embodiments, due to the selection of the shapes of web members and chord members or the types of steel (such as the connection between round tubes in a tower crane), the node connections of the lattice tower have to adopt welding. At the same time, welding is also used to reduce the maintenance workload and connection costs. For example, for a lattice tower made of flat steel or angle iron, although the cost of the steel is low, if bolt connections are used, on the one hand, the cost of the connectors cannot be ignored, and on the other hand, the number of bolt connections will also cause a large amount of maintenance costs in the later stage. These problems are all that the lattice tower must face in common engineering applications such as high-voltage power towers and signal towers.

[0009] When a wind turbine adopts a lattice tower, the challenges it faces are more than those in general engineering fields. The main reason is that in addition to supporting the nacelle and impeller of the wind turbine to a certain height (such as 100 meters above the ground) and bearing the gravity loads of the nacelle and impeller, the lattice tower also needs to face various alternating loads brought about by the continuous and irregular operation of the wind turbine, such as thrust loads and additional bending moment loads, etc. And these alternating loads will inevitably cause fatigue problems on the lattice tower, that is, the fatigue loads that the tower needs to check in the wind power field. In addition, the load magnitude of the wind turbine tower is much higher than that in other general engineering applications. Therefore, the way of node connection will be more complex (for example, general penetrant welding may not be applicable). If bolt connections are used for the node connections of the lattice tower, the influence of fatigue loads will inevitably require maintenance of the bolt connections. And the frequency of this kind of maintenance will definitely far exceed that of engineering applications with almost no influence of fatigue loads (such as signal towers). If the node connections of the lattice tower adopt welding, then the fatigue loads in the wind turbine put forward higher requirements for the welding process and the final quality, and try to avoid problems such as weld cracking as much as possible. And these higher welding processes and welding qualities will ultimately be reflected in the manufacturing cost of the lattice tower.

[0010] Therefore, lattice towers have a long history and have been widely used in many engineering fields due to their high cost performance and other advantages. However, after years of development, they have never become the mainstream technical solution for wind turbine towers.

[0011] In summary, the current use of lattice towers in wind turbines still faces the following technical problems: 1) Different from other engineering applications, wind turbines (whether horizontal-axis or vertical-axis) will cause torsional loads at the top of the lattice tower. The magnitude of this torsional load cannot be ignored. However, due to characteristics such as material distribution, the stiffness of the lattice tower in the torsional direction (the torsional direction around the tower axis) is significantly insufficient compared to that of a steel cylindrical tower. The deformation formed by the lattice tower under torsional loads needs to be controlled to avoid excessive deformation and generate other additional loads. Existing technical solutions can only supplement the torsional stiffness by increasing the specifications of the web members (such as increasing the wall thickness or pipe diameter, etc.) and improving the ability of the web members to withstand compressive stress (to avoid stress overrun), and this solution will inevitably lead to an increase in the cost of the lattice tower. This forms a paradox: the use of a lattice tower in a wind turbine is to reduce the cost of the tower, but due to the special nature of the wind turbine loads and the characteristics of the lattice tower itself, it is necessary to increase the use of materials, resulting in an increase in the tower cost.

[0012] 2) The fabrication of lattice towers involves a large number of node connections (connections between web members and chord members, and even between web members). Due to the shape or type of the chord members and web members, the node structure becomes complex, and welding or bolt connections have to be selected. On the one hand, the cost of the node structure (including material cost and manufacturing cost) increases, and on the other hand, a large number of bolt connections will cause excessive maintenance work, increasing the maintenance cost. If welding is selected, the working characteristics of the wind turbine will put higher requirements on the welding process and quality, resulting in an increase in the production and manufacturing cost. Summary of the Invention

[0013] To solve at least one of the technical problems mentioned above, in a first aspect, a lattice tower is provided, which is composed of main legs, a first support member, and a second support member; there are at least three main legs, and the upper ends of all the main legs are located at the top of the tower, and the top of the tower is horizontally arranged; the lower ends of all the main legs are located at the bottom of the tower, and the bottom of the tower is connected to the foundation; Among any two adjacent main legs, a plurality of first nodes are provided on one of the main legs, and a plurality of second nodes are provided on the other main leg; wherein, for any one of the first nodes, a second node on the same horizontal plane can be found, and this horizontal plane is the node horizontal plane; Each of the first nodes is connected to at least one of the first supports or at least one of the second supports, or is simultaneously connected to one of the first supports and the second support; each of the second nodes is connected to at least one of the first supports or at least one of the second supports, or is simultaneously connected to one of the first supports and the second support; both the first support and the second support are straight rods. Any one of the first supports starts from one of the first nodes and extends to any one of the second nodes below the node horizontal plane where this first node is located. Any one of the second supports starts from one of the second nodes and extends to one of the first nodes below the node horizontal plane where this second node is located, and the second support passes through at least one node horizontal plane. Any one of the first supports intersects and is connected to at least two of the second supports in the middle thereof; simultaneously, any one of the second supports intersects and is connected to at least two of the first supports in the middle thereof.

[0014] In a further technical solution, only one set of the first nodes or one set of the second nodes is provided on each of the main legs.

[0015] The first support and the second support are made of profiled steel.

[0016] The first support and the second support intersect at the first node or the second node on the main leg to form a node connection, and are connected to the main leg by bolt connection, welding or riveting.

[0017] The first way to make the first support or the second support is: between two adjacent main legs, the first support and the second support connected by the first node or the second node are made by bending a complete profile. The second way to make the first support or the second support is: when making the first support, multiple first supports connected by the first node or the second node are made by bending a complete profile towards the bottom of the tower; when making the second support, multiple second supports connected by the first node or the second node are made by bending a complete profile towards the bottom of the tower.

[0018] The connection mode between the middle part of the first support and the second support is lapping; the connection mode between the middle part of the second support and the first support is lapping.

[0019] The main leg is made of metal profile, metal pipe or metal plate.

[0020] The lap joint between the first support member and the second support is connected by bolts, welding or riveting.

[0021] In a second aspect, a wind turbine is provided, which is characterized by including a lattice tower as described above.

[0022] The beneficial effects of the present invention are as follows: A new connection form of the lattice tower is formed by connecting the main leg and two groups of support members. First, the two groups of support members bear tensile and compressive loads by using opposite setting directions, covering two directions where torque loads may be formed, and at the same time being compatible with the torsional direction load-bearing requirements in horizontal-axis and vertical-axis wind turbines. The two types of support members are set differently in the length direction, which can better cope with the situation where obvious torque loads appear in a single direction (such as a vertical-axis wind turbine). Secondly, different from the existing structural form, the two types of support members intersect and connect at least twice in the middle, and the multiple connections of the support members increase the load-bearing capacity of the bending moment load and torsional load of the entire structure. Thirdly, the tower is mainly made of two complete profiled steel bent parts, rather than the support structure composed of multiple sections of web members connected by welding or bolts in the prior art. The integrity of the metal greatly improves the reliability and stability of the structure, and reduces the problems of connection failure caused by fatigue loads in welding and bolt connections or a large amount of maintenance work. Finally, the structure of all node connections is greatly simplified. While the torsional stiffness of the tower is improved, the material and manufacturing costs of the lattice tower can be controlled. Description of the Drawings

[0023] Figure 1 Schematic diagram of a lattice tower structure according to an embodiment of the present invention; Figure 2 Schematic diagram of the setting of the main leg at the bottom of a lattice tower according to an embodiment of the present invention; Figure 3 Schematic diagram of the setting of the first node and the second node of a lattice tower according to an embodiment of the present invention; Figure 4 Schematic diagram of the setting of the first support member and the second support member of a lattice tower according to an embodiment of the present invention; Figure 5 Schematic diagram of the comparison between the lattice tower according to an embodiment of the present invention and the prior art structure; Figure 6 Schematic diagram of the first support member of a lattice tower according to an embodiment of the present invention; Figure 7 Schematic diagram of the first scheme of the first support member of a lattice tower extending in a spiral shape according to an embodiment of the present invention; Figure 8 Schematic diagram of the spiral direction of the first support member and the second support member of the first scheme of a lattice tower according to an embodiment of the present invention; Figure 9 Schematic diagram of the continuous bending extension of the first support member and the second support member of the lattice tower in the second solution according to the embodiment of the present invention.

[0024] Figure 10 Schematic diagram of the continuous bending extension of multiple groups of the first support member and the second support member of the lattice tower in the second solution according to the embodiment of the present invention.

[0025] Figure 11 Schematic diagram of the intersection connection of the first support member and the second support member of the lattice tower according to the embodiment of the present invention.

[0026] Explanation of the reference numerals in the drawings: 1, main leg; 1.1, upper end of the main leg; 1.2, lower end of the main leg; 2, first support member; 3, second support member; 4, first node; 5, second node; 6, node horizontal plane; 7, lap joint.

[0027] It should be noted that the above drawings are used to illustrate the features of the present invention, and are not intended to show any actual structure or reflect details such as the dimensions and relative proportions of various components. In order to more clearly show the principle of the present invention and to avoid unnecessary details from obscuring the principle of the present invention, the examples in each figure have been simplified. These drawings will not cause inconvenience to those skilled in the relevant art when understanding this patent, and the actual embodiments may include more modules or components. Detailed implementation manners

[0028] For the purpose of making the objectives and technical solutions of the embodiments of the present invention clearer, the following will describe the embodiments of the present invention in a complete manner in combination with the relevant drawings of the embodiments of the present invention. This patent only describes a part of the embodiments, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0029] I. Related technical problems of the existing lattice towers of wind turbines The structural forms adopted by the existing lattice towers in wind turbines are very similar to those in other engineering applications: The lattice tower is composed of chord members and web members. The chord members have relatively large pipe diameters and wall thicknesses and mainly play the role of compressive support. At the same time, together with the web members, they provide flexural support. In addition, the web members need to be connected to the chord members to jointly provide torsional support. The ends of the web members are connected together, and adjacent web members are not arranged in parallel to achieve the effect of mutual support between the web members. In some engineering applications using angle irons (such as in power transmission towers and signal towers), a single cross-connection setting between the web members may be used. These structural forms may have a certain effect in resisting bending moment loads, but their ability to withstand torsional loads (or torsional loads) is relatively poor. This is also related to the fact that general engineering applications do not need to withstand torsional loads. Directly applying the existing technology to wind turbines, the torsional load will cause the web members to bear a large compressive stress. The most conventional methods are to add more web members (that is, reduce the length of the web members) or increase the specifications of the web members (wall thickness and cross-sectional area). Both of these methods will undoubtedly increase the material cost. Therefore, a new structural form is needed to better resist the impact of torsional loads.

[0030] In addition, the web members need to intersect and be connected to other web members and chord members at the same time, making the node structure for realizing the connection between the web members and chord members relatively complex. This complexity includes both the selection of the structural form and related engineering calculations, as well as the manufacturing process. Further, the operating characteristics of wind turbines are significantly different from those of other engineering applications: They operate continuously and irregularly for a long time. In addition to the gravitational load caused by their own weight, various complex loads of relatively high magnitudes are accompanied during power generation, such as thrust loads, torsional loads around the impeller shaft, combined bending moment loads and derived additional bending moment loads, and torsional loads around the tower axis, etc., and these loads are all alternating. Therefore, when using a lattice tower, on the one hand, the load-bearing capacity of the web members faces higher requirements, and on the other hand, the requirement for the reliability of the node connection makes the general node solutions not directly applicable to wind turbines. If bolt connections are used, although the connection is more reliable, the node structure will be more complex, and more maintenance work will be required in the later stage to maintain a reliable connection. If welding is used, the node structure may be simplified, but the improvement of the process requirements makes the manufacturing cost significantly higher than that of general welding processes. In addition, the relatively small number of suppliers who can provide processes meeting the requirements will also cause an increase in costs.

[0031] II. Core technical features of this patent The core technical features of the blade support proposed in this patent can be summarized into the following two points: 1) The first support member starts from a first node and extends to any second node below the node horizontal plane where it is located. At the same time, the second support member starts from a second node and extends to a first node below the node horizontal plane where it is located, and the second support member needs to pass through at least one node horizontal plane. That is to say, the extending directions of the second support member and the first support member are opposite, and generally the length of the second support member is longer.

[0032] 2) The first support member intersects and connects with at least two second support members in the middle thereof. At the same time, any second support member intersects and connects with at least two first support members in the middle thereof.

[0033] III. An embodiment of a lattice tower As Figure 1 shown, a lattice tower mainly consists of three types of components: main legs (1), first support members (2), and second support members (3). There are at least three main legs (1). In this embodiment, the number of main legs (1) is four. The main legs (1) are made of metal profiles, metal pipes, or metal plates. In this embodiment, the main legs (1) are made of angle irons, and the four main legs (1) are evenly distributed around the axis of the tower, that is, the cross-section of the tower can be approximately considered a square. In other embodiments, the arrangement of the main legs (1) can be adjusted according to specific requirements. For example, for a lattice tower with four main legs (1), its cross-section can also be rectangular.

[0034] The main legs (1) generally include upper ends and lower ends. The upper ends (1.1) of all the main legs are located at the top of the tower. The top of the tower is horizontally arranged, that is, the upper end surfaces (1.1) of all the main legs are at the same height, which is convenient for connection with the upper nacelle, etc. Correspondingly, the lower ends (1.2) of all the main legs are located at the bottom of the tower. Generally, the angles between the main legs (1) and the foundation installation plane are equal, as Figure 2 shown in this embodiment, and the lengths of the main legs (1) themselves are also equal. In other embodiments, the angle between each leg and the foundation installation plane or the length of the leg can be adjusted according to specific conditions.

[0035] As Figure 3 shown, among any two adjacent main legs (1), multiple first nodes (4) are provided on one main leg (1), and multiple second nodes (5) are provided on the other main leg (1). As in Figure 2In the present embodiment shown, the first node (4) is provided on the main leg (1) on the left, and the second node is provided on the main leg (1) on the right. In actual applications, the positions of the first node (4) and the second node (5) can be completely exchanged, that is, the second node (5) is provided on the main leg (1) on the left, and the first node is provided on the main leg (1) on the right, which does not affect the technical features and universality of the present invention.

[0036] For any first node (4), a second node (5) on the same horizontal plane can be found, and this horizontal plane is the node horizontal plane (6). That is to say, the number of first nodes (4) (or second nodes (5)) is the same as the number of node horizontal planes (6). Figure 3 Only 5 node horizontal planes (6) are shown.

[0037] Each first node (4) is connected to at least one first support member (2) or at least one second support member (3) or simultaneously connected to a first support member (2) and a second support member (3). Similarly, each second node (5) is connected to at least one first support member (2) or at least one second support member (3) or simultaneously connected to a first support member (2) and a second support member (3). The first support member (2) and the second support member (3) are both straight rods.

[0038] Any first support member (2) starts from a first node (4) and extends to any second node (5) below the node horizontal plane (6) where this first node (4) is located. Any second support member (3) starts from a second node (5) and extends to a first node (4) below the node horizontal plane (6) where this second node (5) is located. That is to say, both ends of the first support member (2) and the second support member (3) are respectively connected to the first node (4) and the second node (5), but the setting directions are opposite, so that the first support member (2) and the first support member (2) will necessarily intersect in the middle.

[0039] Different from the first support member (2), the second support member (3) must pass through at least one node horizontal plane (6). As Figure 4As shown, the first support member (2) connects the first node (4) and the nearest second node (5) below the node plane where it is located, while the second support member (3) connects the first node (4) and the second first node (4) below the node plane where it is located. This setting makes the length of the first support member (2) less than the length of the second support member (3); and only this setting can achieve the following technical feature: the first support member (2) intersects and connects with two second support members (3) in its middle. Similarly, the second support member (3) intersects and connects with two first support members (2) in its middle. As the length of the second support member (3) increases (i.e., the number of node planes passed through by the second support member (3) increases), the number of intersections and connections between the first support member (2) and the second support member (3) gradually increases, and can reach more than two in some embodiments. As Figure 5 shown, it can be seen that the setting method ( Figure 5 a, that is, the left figure) proposed in the present invention is significantly different from the existing structural forms ( Figure 5 b and Figure 5 c, that is, the middle figure and the right figure).

[0040] It should be noted that only one set of first nodes (4) or one set of second nodes (5) is provided on each main leg (1). That is to say, according to the foregoing content, each main leg (1) does not have multiple sets of nodes. There is only one set of nodes on each main leg (1), which is either the first node (4) or the second node (5). It is impossible to have two sets of first nodes (4) (or second nodes (5)), nor is it possible to set one set of first nodes (4) and one set of second nodes (5) at the same time.

[0041] As Figure 6 shown, each first support member closest to the upper end of the tower is only connected to the upper end (1.1) of a different main leg. In this embodiment, the connection position is close to the upper end face of the tower, and other embodiments can be adjusted according to actual needs. In this embodiment, actually four first support members (2) and the upper ends (1.1) of four main legs form four sets of connections. The actual connection position of the first support member (2) and the main leg (1) can be selected according to the actual situation, either on the outside or inside of the tower.

[0042] The first implementation manner of the first support member (2) and the second support member (3): As Figure 7As shown, the first support member (2) starts from the upper end (1.1) of the main leg and spirals along all the main legs (1) close to the tower towards the bottom of the tower. Structurally, the first support member (2) extends as a whole from the upper end (1.1) of one main leg along all the main legs (1) in the tower. The extending trajectory of the first support member (2) is similar to a helix, except that since the cross-section of the tower is polygonal (square in this embodiment), the trajectory of the first support member (2) is not as smooth as a helix, but the extending trend is similar. Further, in this embodiment, at the position where the first support member (2) is close to the main leg (1) or where it intersects with the main leg (1), the first support member (2) can be bent or similar operations can be performed so that the extension of the first support member (2) can continue. And, the first support member (2) closest to the bottom of the tower is connected to the lower end (1.2) of one main leg. The first support member (2) closest to the bottom of the tower may be connected to the lower end (1.2) of one main leg nearby due to the actual length of the main leg (1).

[0043] Similar to the setting of the first support member (2): Each second support member (3) closest to the upper end of the tower is only connected to the upper end (1.1) of a different main leg. Similarly, in this embodiment, as Figure 5 shown, in fact, four first support members (2) and four second support members (3) together form four sets of connections with the upper ends (1.1) of the four main legs. In each set of connections, the upper end (1.1) of any one main leg is connected to a first support member (2) and a second support member (3).

[0044] The second support member (3) starts from the upper end (1.1) of the main leg and spirals along all the main legs (1) close to the lower end (1.2) of the main leg, and the second support member (3) closest to the bottom of the tower is connected to the lower end (1.2) of one main leg.

[0045] As Figure 8 shown, the direction in which the first support member (2) spirals along all the main legs (1) towards the bottom of the tower (or the lower end of the main leg) is opposite to the direction in which the second support member (3) spirals along all the main legs (1) towards the bottom of the tower. When observing from the top of the tower towards the bottom of the tower, for the extending directions of the first support member (2) and the second support member (3), one of them can be approximately regarded as extending clockwise towards the bottom of the tower, while the other can be approximately regarded as extending counterclockwise towards the bottom of the tower.

[0046] The second implementation manner of the first support member (2) and the second support member (3): As Figure 9As shown, between any two adjacent main legs (1), the first support member (2) and the second support member (3) with their ends connected to each other are made by bending a complete section steel (such as bending a steel bar or flat steel), forming a complete part. This complete part is "broken line-shaped" in structure. In this way, between two adjacent main legs (1), there are several such parts (in this embodiment, there are three such parts, as Figure 10 shown), and they are respectively connected to the two main legs (1) at the first node (4) and the second node (5), and are connected to each other at their respective midparts. This implementation method enables the first support member (2) and the second support member (3) between two adjacent main legs (1) to also maintain a high structural integrity. And when the first support member (2) and the second support member (3) are connected to the two main legs (1), the structure of the nodes can also be simplified.

[0047] The first support member (2) and the second support member (3) exactly meet at the main leg (1) to form a node connection. It should be particularly noted that the "node" here is not a simple "point" in the geometric sense. In fact, the first support member (2), the second support member (3), and the main leg (1) are all metal parts with actual cross-sectional areas, thicknesses, widths, etc. parameters, and it is impossible to form only a geometric "point" after meeting. The "node" here refers to the node in the steel structure. The node not only connects the first support member (2), the second support member (3), and the main leg (1) together, but also realizes the function of transmitting loads.

[0048] The first support member (2) and the second support member (3) are made of section steel. That is, in a specific implementation, the first support member (2) and the second support member (3) are made of round steel (similar to a steel bar), or flat steel and other steel materials. Since the first support member (2) and the second support member (3) need to maintain structural integrity, and more importantly, they need to be spirally arranged close to all main legs (1), the first support member (2) and the second support member (3) can select section steel with a simple cross-section and a relatively small cross-sectional area. In this embodiment, the first support member (2) and the second support member (3) are both made of round steel, which is easy to bend and is also relatively convenient to form connections.

[0049] As Figure 11 shown, between two adjacent main legs (1), the first support member (2) and the second support member (3) meet and are connected at the midpart, and the specific connection method is lapping (7). Further, the actual lapping (7) adopts bolt connection, welding or riveting.

[0050] Similarly, the connections between the first support member (2), the second support member (3) and the main leg (1) (i.e., the connections at the first node (4) or the second node (5)) are also made by bolt connection, welding or riveting.

[0051] The novelty and advantages of the above technical solution are as follows: a) Taking the main leg (1) as the main part, two types of support members are provided, namely the first support member (2) and the second support member (3). The first support member (2) and the second support member (3) are respectively connected to the upper end (1.1) of the main leg (which is one end at the top of the tower), and extend downward in two ways, namely, spiraling downward or bending unidirectionally, and finally form a connection with the lower end (1.2) of the main leg (which is one end at the bottom of the tower). This not only realizes the complete structural combination of the three components of the first support member (2), the second support member (3) and the main leg (1) into a lattice tower, but also maintains a large range of structural integrity of the first support member (2) and the second support member (3) themselves. This forms a sharp contrast with the existing solutions: the existing solutions include a large number of segmented components, that is, web members, which need to be connected to chord members and at the same time the connections between web members. The solution proposed in the present invention maximizes the use of complete components (the main leg (1), the first support member (2) and the second support member (3)), reduces the number of mechanical connections, increases the structural reliability, and at the same time saves the design, materials, fabrication and maintenance costs of the joints.

[0052] b) The first support member (2) and the second support member (3) are arranged in opposite directions between any two main legs (1), and at the same time, the lengths of the first support member (2) and the second support member (3) are set differently, so that the first support member (2) and the second support member (3) form two or more intersecting connections in the middle. In the existing technology, the connections are only provided at the ends of the web members (corresponding to the first support member (2) or the second support member (3) in this embodiment), or the lengths of the web members are equal and only form one intersecting connection. The solution proposed in the present invention enables more mutual support between the first support member (2) and the second support member (3) of the present invention, thereby improving the support stiffness of the structure, especially the torsional stiffness, and solving the problem that the lattice tower for wind turbines has poor resistance to torsional loads at present.

[0053] c) The first support member (2) and the second support member (3) extend in opposite directions. Regardless of the direction of the torsional load transmitted from the top of the lattice tower (counterclockwise or clockwise), the load can be transmitted downward along either the first support member (2) or the second support member (judged according to the direction) until it reaches the foundation. The force transmission path is simple and direct. Moreover, the first support member (2) and the second support member (3) located between two adjacent main legs (1) form a lap joint (7) and are fixed by means such as riveting or bolt connection. This simplifies the connection structure and saves the connection cost.

[0054] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "upper, lower, front, rear, left and right" is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0055] Unless otherwise clearly defined and limited in the present invention, the terms "installation, connection, and coupling" shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can also be a mechanical connection, an electrical connection, or a direct connection, and can also be indirectly connected through an intermediate medium, or can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0056] Although the present invention has been described with reference to the preferred embodiments, various improvements can be made to it and components therein can be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present invention is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A lattice tower, characterized in that, the lattice tower is composed of main legs (1), first supports (2) and second supports (3); there are at least three main legs (1), and the upper ends (1.1) of all the main legs are located at the top of the tower, and the top of the tower is horizontally arranged; the lower ends (1.2) of all the main legs are located at the bottom of the tower, and the bottom of the tower is connected to the foundation; among any two adjacent main legs (1), multiple first nodes (4) are arranged on one of the main legs (1), and multiple second nodes (5) are arranged on the other main leg (1); wherein, for any one of the first nodes (4), a second node (5) on the same horizontal plane can be found, and this horizontal plane is the node horizontal plane (6); each first node (4) is connected to at least one of the first supports (2) or at least one of the second supports (3) or simultaneously connected to one first support (2) and the second support (3); each second node (5) is connected to at least one of the first supports (2) or at least one of the second supports (3) or simultaneously connected to one first support (2) and the second support (3); the first supports (2) and the second supports (3) are both straight rods; any one of the first supports (2) starts from one of the first nodes (4) and extends to any one of the second nodes (5) below the node horizontal plane (6) where this first node (4) is located; any one of the second supports (3) starts from one of the second nodes (5) and extends to one of the first nodes (4) below the node horizontal plane (6) where this second node (5) is located, and the second support (3) passes through at least one node horizontal plane (6); any one of the first supports (2) intersects and is connected to at least two of the second supports (3) in the middle; at the same time, any one of the second supports (3) intersects and is connected to at least two of the first supports (2) in the middle.

2. The lattice tower according to claim 1, characterized in that, Only one set of the first nodes (4) or one set of the second nodes (5) is arranged on each main leg (1).

3. A lattice tower according to claim 1, characterized in that, The first supports (2) and the second supports (3) are made of section steel.

4. The lattice tower according to claim 1, characterized in that, The first supports (2) and the second supports (3) intersect at the first nodes (4) or the second nodes (5) on the main legs (1) to form node connections, and are connected to the main legs (1) by bolt connection, welding or riveting.

5. A lattice tower according to claim 1, characterized in that, The first way to make the first support (2) or the second support (3) is: between two adjacent main legs (1), the first support (2) and the second support (3) connected by the first node (4) or the second node (5) are made by bending a complete section steel.

6. The lattice tower according to claim 1, characterized in that, The second way to fabricate the first support member (2) or the second support member (3) is as follows: when fabricating the first support member (2), a plurality of the first support members (2) connected through the first node (4) or the second node (5) are made by bending a complete profile towards the bottom of the tower; when fabricating the second support member (3), a plurality of the second support members (3) connected through the first node (4) or the second node (5) are made by bending a complete profile towards the bottom of the tower.

7. A lattice tower according to claim 1, characterized in that, The connection mode between the middle part of the first support member (2) and the second support member (3) is lapping (6); the connection mode between the middle part of the second support member (3) and the first support member (2) is lapping (6).

8. A lattice tower according to claim 1, characterized in that, The main leg (1) is made of metal profile, metal pipe or metal plate.

9. The lattice tower according to claim 1, characterized in that, The lapping (6) between the first support member (2) and the second support is connected by bolts, welding or riveting.

10. A wind turbine, characterized in that, Comprising a lattice tower according to any one of claims 2-9.

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