Abstract:
The invention relates to a connection between components of a wind turbine. More specifically, the present invention relates to components for a wind turbine having a diameter of more than 0.5 m, preferably more than 1.0 m, and more preferably more than 1.5 m. The wind turbine includes two components that are connected together, whereby each component has a contact surface. The surface of the contact surface of a first component is softer than the surface of the contact surface of a second component. Further, the surface of the contact surface of the second component is annealed.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to components for a wind turbine. More specifically, the present invention relates to a connection between components for a wind turbine having a diameter of more than 0.5 m, wherein the components each have a contact surface. 
         [0002]    In order to connect large-volume components of a wind turbine during installation, maintenance, or repair, flange connections or screw connections are provided between components, such as between a rotor shaft and a drive input or between the rotor shaft and a rotor hub. 
         [0003]    In addition, screw connections are provided between the connection of a tubular tower and a pivot bearing or between a machine support and other components such as a rotor mount, a gearbox mounting, an axle journal, or a (ring) generator. 
         [0004]    Based on this state of the art, the object of the invention is to improve the connection between large-volume components of a wind turbine, where it should be possible to increase the load bearing capacity of highly stressed screw connections or the like. 
       BRIEF SUMMARY OF THE INVENTION 
       [0005]    The object is solved by providing a connection between components of a wind turbine having a diameter of more than 0.5 m, preferably more than 1.0 m, and more preferably more than 1.5 m, wherein two components to be connected together each have facing contact surfaces and the two components are or become braced together in a connected state, wherein a surface of the contact surface of a first component of the wind turbine is softer than a surface of the contact surface of a second component of the wind turbine, and wherein the surface of the contact surface of the second component is annealed. 
         [0006]    Due to the fact that the surface of the contact surface of the second component is harder than the surface of the contact surface of the first component, a detachable connection of mechanically highly stressed components of a wind turbine are achieved, which has higher friction coefficients than the previously known connections of components of a wind turbine. 
         [0007]    Through corresponding connection elements or screws the like, a preloading is created or formed between the components such that a force-fit connection is achieved between the components. A friction-coefficient-increased coupling of the components is thereby achieved between the two components through the preloading applied via the connection elements based on a micro-plastic deformation of the contact surfaces created during the joining procedure, whereby higher friction coefficients of the connection are achieved. 
         [0008]    This is especially important in the use or installation of wind turbines because the wind turbine is either installed or repaired under very unfavorable installation and repair conditions. Through the connection according to the invention, it is possible to connect extremely heavy, partially dirty or oiled components at heights of up to 120 m in unfavorable weather conditions, such as snow, ice or rain, with a mechanically highly stressed connection between the components, wherein the load-bearing capacity of the components of the connection is or will be increased simultaneously through the formation of a friction-coefficient-increased connection between the contact surfaces. 
         [0009]    Within the framework of the present invention, the characteristic “annealed” or “harder surface” of a component means that a component made of a normalized substance, e.g. heat-treatable steel, is produced with an existing harder surface through production and that a finished component in processing steps in accordance with a preferred annealing process is provided with a harder surface. 
         [0010]    Within the framework of the present invention, a connection is understood to be a flange connection of components. Furthermore, in the framework of the present invention, a component is understood to be a functional group or system group or a functional unit or system unit of a wind turbine, e.g. a rotor hub, a rotor shaft, a gear, which is or becomes mechanically coupled with another functional/system group or functional/system unit of the system via the connection according to the invention, in particular a screw connection or flange connection. The components or functional units or system units are in particular large-volume components with weights of more than 100 kg up to several tons. 
         [0011]    Moreover, the connection is characterized in that the surface of the contact surface of the second component has a higher roughness than the surface of the contact surface of the first component. The micro-plastic deformation in the soft surface of the contact surfaces of the first component is hereby improved. Overall, this increases the frictional connection of the components of a wind turbine that are to be connected. 
         [0012]    In particular, the connection is further characterized in that the frictional connection between the first and the second component is or becomes increased in comparison to a connection of the first and second component where the second component does not have an annealed surface. A detachable connection with high friction coefficients is thereby achieved between the contact surfaces of the components to be connected. Further, in the event that maintenance is performed on the wind turbine or on the components of the wind turbine, the detached connection between the components after dismantling ensures a connection between the components subsequently during reinstallation with a high frictional connection. 
         [0013]    Moreover, it is provided in a further embodiment that the second component is or will be arranged as an intermediate connection part or an intermediate connection component between the first component and a third component. This enables a force-fit connection between the first and the third components with a second component arranged in between. 
         [0014]    It is furthermore provided that the surfaces of the contact surfaces of the second component each have a higher hardness and roughness than the surfaces of the contact surfaces of the first and third component lying opposite the contact surfaces of the second component. 
         [0015]    In particular, it is thereby possible that the frictional connection between the third and the second component is or becomes increased in comparison to a connection of the third and second component where the second component does not have an annealed surface. 
         [0016]    Preferably, the first and the second component are connected with each other by means of a flange connection. Alternatively, the first and the third component are also connected with each other by means of a flange connection. 
         [0017]    Advantageously, the first and the second component are or become preloaded by connection elements, preferably screws or the like, e.g. bolts, so that a force-fit connection is formed between the first and the second component of a wind turbine. Alternatively, the first and the third component are or become preloaded through connection elements, preferably screws, bolts or the like. 
         [0018]    Moreover, it is suggested in a further embodiment that the intermediate connection part or component, which is or will be arranged as the second component between the first and the third component, is or will be penetrated by the connection elements. 
         [0019]    It is hereby preferred if the intermediate connection part or component is made up of or has several in particular plate-like or block-like intermediate connection bodies. For this, it is further provided in one embodiment that the intermediate connection bodies form a type of segmented ring, in particular a segmented annular ring or parts thereof for or through arrangement between the first and the third component. 
         [0020]    Preferably, the intermediate connection bodies are or will be connected with the first and/or the second component mechanically by means of mounting elements, in particular screws or pins or clamps or the like. 
         [0021]    In accordance with another embodiment, the contact surfaces of the first and/or the second component and/or the third component are designed or arranged in a ringlike and/or closed manner. 
         [0022]    Moreover, it is preferred that the connection or the frictional connection between the components has a friction coefficient of more than 0.4, preferably more than 0.5, and in particular more than 0.6. 
         [0023]    In particular, the first component is designed as a rotor shaft. 
         [0024]    Furthermore, it is provided that the second component is designed as a rotor hub or as a gear input shaft. If the connection consists of a rotor shaft (first component) and a rotor hub (third component) and an intermediate connection part (second component) is arranged between the first and the third component, a three-part connection is hereby provided. The third component is hereby designed as a rotor hub or as a gear input shaft. 
         [0025]    In one alternative, the first component is designed as a machine frame or a tubular tower. For this, it is further provided that the second or the third component is designed as a pivot bearing, which is or will be arranged on the tubular tower. 
         [0026]    Advantageously, the connection is designed as a force-fit, in particular detachable, connection, in particular transverse-force-loaded and/or torsion-loaded connection or screw connection. 
         [0027]    Preferably, the first or second or third component is a casting component, preferably with (connection) diameters of 0.5 m to 1 m. 
         [0028]    Moreover, the object is solved through the use or the arrangement of components in the case of at least one connection described above of two or three components of a wind turbine. A two-part or three-part connection is hereby designed. In order to avoid repetitions, we expressly refer to the above embodiments. 
         [0029]    The object is also solved by means of a method for producing a connection of components of a wind turbine, wherein a connection is designed according to one of the above exemplary embodiments. 
         [0030]    The object is also solved by a wind turbine, which is designed with a connection described above. 
         [0031]    The invention is described below in an exemplary manner, without restricting the general intent of the invention, based on exemplary embodiments in reference to the drawings, whereby we expressly refer to the drawings with regard to the disclosure of all details according to the invention that are not explained in greater detail in the text. 
         [0032]    Additional benefits and advantages of the present invention become apparent to those skilled in the art to which it pertains upon a reading and understanding of the following detailed specification. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0033]      FIG. 1  shows the cross-section of the connection of a rotor shaft with a rotor hub and a section of the gear; 
           [0034]      FIG. 2  shows a detailed view of the connection transition of the rotor shaft with the gear; 
           [0035]      FIG. 3   a  shows the flange connection of the rotor hub with the rotor shaft in a detailed view; 
           [0036]      FIG. 3   b  shows the view of a flange connection of the rotor hub with a cut rotor shaft; 
           [0037]      FIG. 4   a - 4   d  show views of circular segment intermediate bodies in view representations and 
           [0038]      FIG. 5  shows a detailed view of the connection transition of the rotor shaft with the gear in accordance with another embodiment. 
       
    
    
       [0039]    The invention may take physical form in certain parts and arrangement of parts, a preferred embodiment of which will be described in detail in this specification and illustrated in the accompanying drawings that form part of the specification. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0040]    In the following figures, for simplicity the same or similar types of elements or corresponding parts are provided with the same reference numbers. 
         [0041]      FIG. 1  shows a cross-section of a connected arrangement of a rotor hub  11  with a rotor shaft  12  and a connection part  13  of a corresponding gear of a wind turbine. The rotor hub  11 , the rotor shaft  12  and the gear (not shown), which has the connection part  13  in the front area, are parts of a schematically indicated wind turbine WEA. 
         [0042]    As shown in  FIG. 2 , the rotor shaft  12  is connected with the connection part  13  of the gear by means of a flange connection  14 . For this, the rotor shaft  12  has a flange ring  15  on the end facing the connection part  13 , which has corresponding bore holes  16  for receiving screws. The bore holes  16  are arranged at regular intervals around the perimeter of the flange ring  15 . The connection part  13  of the gear has corresponding tapped blind holes  17  on the side facing the rotor shaft  12 , which have corresponding threads. From the rotor shaft side, screws  18  with thread are inserted into the bore holes  16  of the rotor shaft  12  and the bore holes  17  of the connection part  13  so that the rotor shaft  12  is connected with the connection part  13  under the formation of preloading. 
         [0043]    Intermediate connection bodies  20 , which are located in a detachable manner between the rotor shaft  12  and the connection part  13 , are arranged between the end of the rotor shaft  12  and the end of the connection part  13 , which is arranged opposite the rotor shaft  12 , in the area of the bore holes  16 ,  17 . In accordance with the invention, the intermediate connection bodies  20  are provided with a harder contact surface than the contact surfaces of the rotor shaft  12  and the connection part  13  on both sides of the rotor shaft  12  and the connection part  13 , such that the friction coefficient and the frictional connection between the rotor shaft  12  and the connection part  13  are or will be increased by pulling the screws  18 . 
         [0044]    In the case of dismantling, i.e. loosening the connection between the rotor shaft  12  and the connection part  13  by unscrewing the screws  18 , it is possible that the intermediate connection bodies  20  on the detachable connection between the two components can be manually removed. The contact surfaces of the rotor shaft  12  and the connection part  13 , which lie opposite each other, are preferably smooth. Typically, the ends of the rotor shaft  12  and the connection part  13  are greater than 0.5 m in diameter. 
         [0045]    Alternatively, the connection of the rotor shaft  12  to the connection part  13  can also be established without intermediate connection bodies. This is available in particular when the connection part  13  is designed as a forged planet carrier with an annealed contact surface. The shaft can then be poured e.g. from EN-GJS 400. Alternatively, the shaft can also be annealed, in particular if it is designed as a forged part. 
         [0046]      FIG. 3   a  also shows a detailed view of a cross-section of the connection between the rotor shaft  12  and the rotor hub  11  (see  FIG. 1 ). For this, the rotor hub  11  has a flange ring  19  on the inside with corresponding bore holes, into which bolts or screws can be inserted and connected with the front side of the rotor shaft  12 . For this, corresponding tapped blind holes are provided on the rotor shaft  12  for receiving the screws or bolts. 
         [0047]    The screws or bolts are inserted from the inside of the rotor hub  11  and connected with the rotor shaft  12 . Furthermore, in order to form an alternating flange connection on the rotor shaft  12 , a flange ring  21  with corresponding bore holes are provided for receiving bolts or screws. The bolts are hereby inserted into the bore holes of the flange ring  21  from the side facing away from the rotor hub  11  such that the bolts or screws penetrate correspondingly formed (tapped blind holes or through) holes on the rotor shaft  11 , whereby the bolts of the outer row of the flange ring  21  are arranged against the bolts of the inner row of the flange ring  19  of the rotor shaft  11 . The hole circle of the bore holes of the flange ring  21  is hereby greater than the hole circle of the bore holes of the flange ring  19 . 
         [0048]    Overall, this enables a double-row screw flange connection of the two mechanically highly stressed components, wherein the assembly takes place in that the rotor hub and the rotor shaft are aligned with each other, then the screw connection of the row of bolts on the outer lying flange ring  21  of the rotor shaft  12  takes place and then the connection elements in the form of bolts or screws are screwed in the inside of the rotor hub  11  on the inner lying flange ring  19 . Then the bolts or screws are preloaded with a predetermined preload force. This enables a robust flange connection of the rotor hub  11  with the rotor shaft  12 . 
         [0049]    Due to casings  25  under the screw heads of the inner screw row, it is possible to use uniform screw lengths for the purpose of standardization. A track  24 , which functions as a contact track for a lightening arrestor (not shown), is arranged on the outer flange ring  21 . 
         [0050]    In order to form a friction-value-increased connection between the rotor hub and the rotor shaft, intermediate connection components  20  are provided in the form of a locking disk. The surfaces of the contact surfaces to rotor hub  11  and rotor shaft  12  are designed harder than the contact surfaces of rotor hub  11  and rotor shaft  12  so that the frictional connection in the case of the preloading of the bolt row on the flange rings  19 ,  21  leads to a better friction coefficient. Alternatively, the flange connection can also be designed without intermediate connection components  20  in that the surface of the contact surface of the rotor shaft  12  is designed harder than the contact surface of the rotor hub  11 . This is offered in particular when the rotor hub  11  is designed as a casting component and the rotor shaft  12  is designed as a forged component made of heat-treatable steel. 
         [0051]    Through the connection according to the invention of large-volume components of a wind turbine with or without intermediate connection components with harder surfaces on both sides of the components to be connected, rotor hub  11  and rotor shaft  12 , an arrangement is achieved for preventing relative movements between the components (rotor hub  11  and rotor shaft  12 ) that are braced against each other and work together in a frictionally engaged manner. 
         [0052]    In particular, the rotor hub  11  is a component made of a cast material, e.g. nodular graphite casting, or made of simple structural steel, wherein the contact surface of the flange ring  20  for the rotor shaft is preferably processed to be mechanically smooth, e.g. RZ 16. 
         [0053]    Moreover, the rotor shaft  12  is designed as a second component as a steel component (structural steel or heat-treatable steel) or as a casting component with a harder surface of the contact surface than the contact surface of the rotor hub  11 . Preferably, the surface of the contact surface is sand-blasted with a sharp-edged shot, e.g. sand-blasted with SA 3 quality, and then annealed through e.g. thermo-physical methods (e.g. flame annealing or induction annealing) or through thermo-chemical methods (e.g. long-term gas-nitro carborizing). For example, a hardness of at least 400 HV (Vickers hardness), preferably greater than 550 HV, is hereby achieved. The density of the hardness layer should be approx. 0.6 mm or greater. 
         [0054]    The preloading applied by the connection elements or bolts between the rotor shaft  12  and the rotor hub  11  should achieve surface pressures on the contact surfaces in the range of 60 to 220 N/mm 2 , preferably between 90 and 200 N/mm 2 . Friction coefficients of the connection from the rotor shaft with the rotor hub above 0.4, preferably above 0.5, are hereby implemented in a very cost-efficient and reliable manner. 
         [0055]    Furthermore,  FIG. 3   b  shows a view of the flange ring  19  of the rotor hub  11 . It can be seen from this that the bore holes of the flange ring  19  are arranged in a circular manner, wherein the connection area of the rotor hub  11  to the rotor shaft on the flange ring  19  has a diameter of more than 0.5 m overall. 
         [0056]      FIGS. 3   a  and  3   b  also show that the intermediate connection bodies  20  can simultaneously be used as a locking disk for a rotor lock. The locking disk is made up of three identical segments, which are designed as intermediate connection bodies  20 . The locking takes place via two locking devices  26 , in which bolts (not shown) are pushed through the bolt receivers  27 . At total of 12 bolt receivers  27  are positioned such that each rotor blade is lockable in a vertical and horizontal position. The three recesses  28  in the locking disk make it possible for maintenance personnel to climb into the rotor hub casing. It is particularly economical when the locking disk is made of remaining pieces of the machine frame production. 
         [0057]    The rotor hub casing (not shown) is preferably fastened to the intermediate elements  20  in order to not interrupt the flow of power in the rotor hub through additional fastenings (gatings). 
         [0058]      FIGS. 4   a  through  4   d  show one view different embodiments of the arrangement of intermediate connection bodies  20  of a component or a flange of a component. The left area of  FIGS. 4   a  through  4   c  each show a circular arrangement of the intermediate connection bodies  20  and the right area of the figures each show a single view of the intermediate connection bodies  20 . 
         [0059]    By means of the contact surfaces of the intermediate connection bodies  20  between the contact surfaces of two components which are harder on one side, preferably harder on both sides, of the contact surfaces of components, in particular the contact surfaces of a flange connection between the components, a type of segmented ring is formed from the intermediate connection bodies  20 . The intermediate connection bodies  20  are designed as a partial segment of a circular arrangement. 
         [0060]    The intermediate connection bodies  20  can have one or more through holes  22 , so that the intermediate connection bodies  20  are penetrated by bolts or screws of a flange connection between two components to be connected. Moreover, the intermediate connection bodies  20  have smaller bore holes  23  so that mounting elements in the form of counter-sunk screws penetrate the bore holes  23 , whereby for example the mounting of the intermediate connection bodies  20  on a flange ring is enabled or simplified. 
         [0061]    The intermediate connection bodies  20  can hereby be mounted on the contact surfaces of the components through the insertion of screws or other mounting elements into the bore holes, wherein the contact surfaces preferably have corresponding tapped blind holes for receiving threads. 
         [0062]    Within the framework of the invention, it is also possible that on the intermediate connection bodies  20  corresponding immobilization devices  20  or positioning devices for the immobilization or arrangement of the intermediate connection bodies  20  are provided on a component or on a flange of a component. 
         [0063]    Due to the fact that a second component ( FIG. 2 ) is provided between a first and a third component ( 11 ,  13 ), which has a higher hardness on its contact surfaces to the first and the third component ( 11 ,  13 ), the second hard component ( 20 ) can be designed in a plate-like manner or like a sort of intermediate element or intermediate connection part with intermediate connection bodies. This minimizes the costs for an annealing of the surfaces of the first and third components ( 11 ,  13 ). Depending on the annealing method, it is hereby advantageous to restrict the size of the intermediate connection bodies through segmentation. In particular in the case of ring flange connections, the intermediate connection bodies are preferably designed as annular ring elements. 
         [0064]      FIG. 5  shows another exemplary embodiment of a connection of a rotor shaft  12  with a gear flange  130  of a gear (not shown further) according to the embodiment shown in  FIG. 2 . A locking disk  30  is hereby arranged between the rotor shaft  13  and the gear flange  130 , which has both contact surfaces to the rotor shaft  12  and the gear flange  130 . 
         [0065]    In order to improve the stability of the connection between the rotor shaft  12  and the locking disk  30  or between the rotor shaft  12  and the drive flange  130 , intermediate connection bodies  20 , which are provided with a coating on the surface, are arranged between the rotor shaft  12  and the locking disk  130 . Furthermore, the locking disk  30  is provided with through holes, so that schematically indicated screws  31 , which are inserted on the gear flange side, a washer  32 , the locking disk  30  and the provided through holes of the intermediate connection bodies  20  penetrate and empty into tapped blind holes of the rotor shaft  12 . The washer  32  ensures better load distribution. 
         [0066]    Furthermore, intermediate connection bodies  20  are arranged between the locking disk  30  and the gear flange  130  so that the gear flange  130  and the locking disk  30  are connected with schematically indicated screws  33 . The intermediate connection bodies  20  are annealed and/or coated intermediate connection bodies  20  according to the invention such that improved force-fit connections with higher frictional connections result. 
         [0067]    The embodiment shown in  FIG. 5  is the multiple combination or a series connection of several connections according to the invention. 
         [0068]    While specific embodiments of the invention have been described and illustrated, it is to be understood that these embodiments are provided by way of example only and that the invention is not to be construed as being limited but only by proper scope of the following claims.