Abstract:
The invention relates to a rotor for a wind turbine of the type having a rotor hub ( 8 ) and a set of rotor blades ( 9 ). Each rotor blade ( 9 ) is rotatably mounted on the rotor hub ( 8 ) for rotation about a blade axis ( 11 ). A threaded spindle mechanism ( 13 ) interconnects the rotor blade ( 9 ) and the rotor hub ( 8 ). The threaded spindle mechanism ( 13 ) includes a spindle nut ( 32 ), a threaded spindle ( 31 ) and a drive ( 21 ) mounted on the rotor blade ( 9 ) adjacent a transition between the rotor hub ( 8 ) and the rotor blade ( 9 ). The drive ( 21 ) is rotatable together with the rotor blade ( 9 ) about the blade axis ( 11 ) relative to the rotor hub ( 8 ) by actuation of the threaded spindle mechanism ( 13 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a 371 U.S. National Stage of International Application No. PCT/EP2010/066556, filed Nov. 1, 2010, and claims priority to German Patent Application No. 10 2009 044 667.2 filed Nov. 26, 2009, the disclosures of which are herein incorporated by reference in their entirety. 
     FIELD 
     The invention relates to wind turbines, and more particularly to a rotor for a wind turbine, with a rotor hub, at least one rotor blade rotatably mounted about a blade axis on the rotor hub, and at least one threaded spindle mechanism which is installed between the rotor hub and the rotor blade and is connected to both the rotor hub and the rotor blade, and is rotatable about the blade axis relative to the rotor hub by actuation of the threaded spindle mechanism, which comprises a spindle nut, a threaded spindle and a drive. 
     BACKGROUND 
     Such a rotor is described in German Patent Applications 10 2008 055 473.1 and 10 2009 045 467.5. In previous constructions the drive of the threaded spindle mechanism mounted on the rotor hub is located at a relatively large distance from the rotor blade, so that access to the drive is difficult for service staff. In some cases the drive is even arranged outside the interior of the rotor hub, so that apart from a further complication as regards accessibility, measures also have to be taken against lightning strikes and other meteorological influences. 
     SUMMARY 
     Against this background the object of the invention is to improve the accessibility of the drive of the threaded spindle mechanism in a rotor of the type mentioned in the introduction. 
     This object is achieved according to the invention with a rotor according to the present disclosure. 
     The rotor according to the invention for a wind turbine comprises a rotor hub, at least one rotor blade rotatably mounted about a blade axis on the rotor hub, and at least one threaded spindle mechanism which is installed between the rotor hub and the rotor blade and is connected to both the rotor hub and the rotor blade, and is rotatable about the blade axis relative to the rotor hub by actuation of the threaded spindle mechanism, which comprises a spindle nut, a threaded spindle and a drive, which is mounted on the rotor blade in the region of the transition between the rotor hub and the rotor blade, and can rotate together with this about the blade axis. 
     Due to the arrangement of the drive, the latter is readily accessible to service staff and is simple to maintain. In particular, the drive is arranged in the handling area of the rotor hub so that it is easily within arm&#39;s reach of a service person working in the rotor hub. 
     The spindle nut is connected in particular via a screw connection to the threaded spindles. Preferably the spindle nut is screwed onto the threaded spindle. The rotor hub includes in particular an inner chamber. In addition the rotor blade includes in particular an inner chamber, which is preferably adjacent to the inner chamber of the rotor hub. In particular the inner chamber of the rotor blade is joined to the inner chamber of the rotor hub. Preferably the inner chamber of the rotor blade transforms into the inner chamber of the rotor hub. 
     According to a first variant of the invention the drive projects into the inner chamber of the rotor hub and/or the drive is arranged in the inner chamber of the rotor hub. The drive is in this case particularly easily accessible, but also takes up installation space in the interior of the rotor hub. According to a second variant of the invention the drive projects into the inner chamber of the rotor blade and/or the drive is arranged in the inner chamber of the rotor blade. In this way the installation space taken up by the threaded spindle mechanism in the inner chamber of the rotor blade can be reduced. Furthermore access to the drive is only slightly more difficult compared to the first variant, and its accessibility is still acceptable. 
     A wall element is preferably secured to the end of the rotor blade facing towards the rotor hub, and serves in particular to stabilise the rotor blade. The wall element is preferably arranged on the front face of the rotor blade and separates in particular the inner chamber of the rotor blade from the inner chamber of the rotor hub. Preferably the wall element extends transverse to the blade axis. Preferably the wall element traverses or spans, in particular completely or at least partly, the inner chamber of the rotor blade or the opening of the rotor blade facing towards the rotor hub transverse to the blade axis. Furthermore the wall element can be installed in the inner chamber of the rotor blade. Preferably the wall element covers, in particular completely or partly, the inner chamber of the rotor blade. The wall element is preferably rigidly connected to the rotor blade and/or is connected in a torque-resistant manner with respect to a rotation about the rotor blade, so that it can rotate together with the rotor blade about the blade axis. Preferably a window-like opening is provided in the wall element, through which access to the inner chamber of the rotor blade can be gained from the inner chamber of the rotor hub. According to a modification of the invention the drive is mounted on the wall element. 
     The drive can be rigidly secured to the rotor blade and/or to the wall element. Preferably however the drive is rotatably mounted on the rotor blade and/or the wall element about a blade-side swivel axis, which runs in particular in the direction of the blade axis and is preferably spaced from the latter. Accordingly, the threaded spindle mechanism can, for example, be prefabricated as a module and can preferably be mounted as a whole unit. 
     The threaded spindle together with the spindle nut preferably forms a sub-assembly. According to a modification of the invention the sub-assembly formed from the threaded spindle and the spindle nut is rotatably mounted on the rotor hub about a hub-side swivel axis, which runs in particular in the direction of the blade axis and is preferably spaced therefrom. The threaded spindle is preferably coupled to the drive and can be rotated by this about its longitudinal axis, the spindle nut being mounted on the rotor hub. In particular the spindle nut is mounted on the rotor hub so as to be able to swivel about the hub-side swivel axis. 
     According to a development of the invention the threaded spindle mechanism comprises an actuating member coupled to the spindle nut, by means of which the spindle nut is mounted on the rotor hub. In particular the actuating member is mounted on the rotor hub so as to be able to swivel about the hub-side swivel axis. 
     According to a modification of the invention the threaded spindle is detachably coupled to the drive. Preferably the actuating member is also detachably coupled to the spindle nut. Thus, the sub-assembly formed from the threaded spindle and spindle nut can be separated from the threaded spindle mechanism. Since this sub-assembly is subject to a relatively high level of wear, the fact that it can be detached facilitates the maintenance of the threaded spindle mechanism. In particular the sub-assembly can be replaced without having to dismantle the whole threaded spindle mechanism. The threaded spindle is preferably coupled to the drive via the interconnection of a coupling shaft, to which the threaded spindle is detachably secured by at least one securement means. The coupling shaft is coupled to the drive and can be rotated by the latter. The sub-assembly is preferably connected between the coupling shaft and the actuating member. 
     According to a development of the invention the threaded spindle mechanism comprises a transmission, the threaded spindle being coupled to the drive via the interconnection of the transmission. The threaded spindle is arranged in particular outside the drive. The transmission is formed for example as a gear mechanism, as a belt drive or as a planetary gear mechanism. Accordingly, conventional drives can be used so that cost savings can be made. According to a modification of the invention the transmission is connected between the drive and the coupling shaft. Furthermore, the coupling shaft can form an output or take-off shaft of the transmission. Preferably the drive is mounted via the transmission and/or its transmission housing on the rotor blade and/or on the wall element. 
     The drive comprises in particular a drive shaft, which is coupled preferably directly or indirectly, for example via the transmission, to the threaded spindle. A rotation of the threaded spindle about its longitudinal axis can thus be produced by a rotation of the drive shaft about its longitudinal axis. The coupling shaft can be formed for example by the drive shaft, by the output shaft of the transmission, or by another shaft that is connected between the threaded spindle and the drive and/or the transmission. Preferably the drive comprises at least one motor with a motor shaft, so that the drive shaft is formed in particular by the motor shaft or is coupled thereto. The drive is in particular an electric drive. The motor is preferably an electric motor. 
     The drive together with the rotor blade can rotate about the blade axis relative to the rotor hub. This rotatability has to be taken into account when installing connecting lines, via which the drive is supplied. This additional effort and expenditure is however more than compensated by the easier accessibility of the drive and the lower maintenance costs associated therewith. In the case of an electric drive the connecting lines are electrical connecting lines, via which the drive is supplied with electric current. 
     According to a first alternative of the invention the drive shaft of the drive coupled to the threaded spindle runs transverse to the longitudinal axis of the threaded spindle. With this arrangement the drive can in some cases be subjected to relatively high gyroscopic loads. According to a second alternative of the invention the drive shaft of the drive coupled to the threaded spindle therefore runs parallel to the longitudinal axis of the threaded spindle. The threaded spindle mechanism can thus be designed more compactly as regards the drive, so that gyroscopic loads of the drive can be reduced. 
     The invention furthermore relates to a wind turbine with a nacelle, a rotor rotatably mounted about a rotor axis on the nacelle and which can be rotated about the rotor axis by the wind, and a generator mechanically coupled to the rotor. The generator can be electrically driven by the rotor, wherein the rotor is a rotor according to the invention and can be developed in accordance with all modifications described in this connection. In particular the blade axis runs transverse or substantially transverse to the rotor axis. By means of the threaded spindle mechanism the rotor blade can rotate about its blade axis relative to the rotor hub, whereby preferably the rotational speed of the rotor and thus also the rotational speed of the generator can be varied. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The invention is described hereinafter with the aid of preferred exemplary embodiments and with reference to the drawings, in which: 
         FIG. 1  is a schematic representation of a wind turbine with a rotor according to a first embodiment of the invention, 
         FIG. 2  is an internal view of the rotor hub visible in  FIG. 1 , 
         FIG. 3  is a schematic and partly sectional plan view of one of the blade angle adjustment drives according to  FIG. 2 , 
         FIG. 4  is a schematic side view of a part of the blade angle adjustment drive according to  FIG. 3 , 
         FIG. 5  is a schematic and partly sectional side view of another part of the blade angle adjustment drive according to  FIG. 3 , 
         FIG. 6  is a schematic and partly sectional view of the transmission visible in  FIG. 3 , 
         FIG. 7  is a schematic and partly sectional view of a transmission according to a second embodiment of the invention, and 
         FIG. 8  is a schematic and partly sectional side view of a blade angle adjustment drive according to a third embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     A wind turbine  1  is shown in  FIG. 1 , in which a tower  3  standing on a foundation  2  is connected at its end remote from the foundation  2  to a machine house  4 . The machine house  4  comprises a nacelle  5 , on which a rotor  6  is rotatably mounted about a rotor axis  7 , said rotor comprising a rotor hub  8  and rotor blades  9  and  10  connected thereto, which are respectively rotatable about their blade axis  11  and  12  relative to the rotor hub  8 . The rotor blades  9  and  10  are respectively mechanically coupled to a blade angle adjustment drive  13  and  14 , by means of which the respective rotor blade can be rotated about the associated blade axis. The rotor  6  can be rotated about the rotor axis  7  by the wind  15  and is mechanically coupled to an electric generator  16 , which is secured to the nacelle  5  and in particular is arranged in the machine house  4 . A wind turbine control unit  17  is provided for the controlled operation of the wind turbine  1 , by means of which inter alia the blade angle adjustment drives  13  and can be controlled. Although only two rotor blades are shown, the rotor can also comprise three or more rotor blades. 
     An inner view of the rotor hub  8  is shown in  FIG. 2 , in which the rotor blade  9  has an inner chamber  18  and is closed on the front by a wall element  19  at its end facing towards the rotor hub  8 . The wall element  19  serves to stabilise the rotor blade  9  and separates the inner chamber  18  of the rotor blade  9  from the inner chamber  45  of the rotor hub  8 . The wall element  19  is provided with a window-like opening  20 , through which access to the inner chamber  18  can be gained. The blade angle adjustment drive  13  engages with the wall element  19  and has a drive  21  formed by an electric motor, a transmission  22  and a linear adjustment member  23 , which is mounted on the rotor hub  8  on its side facing away from the rotor blade  9 . The drive  21  is connected to electrical connecting lines  24  and can be supplied by the latter with electric current. The connecting lines  24  are routed by means of cable holders  25  in the rotor hub  8  in such a way that they can follow a movement of the drive  21  relative to the rotor hub  8 . 
     The rotor blade  10  comprises an inner chamber  26  and is closed at the front by a wall element  27  at its end facing towards the rotor hub  8 . The wall element  27  serves to stabilise the rotor blade  10  and separates the inner chamber  26  of the rotor blade  10  from the inner chamber  45  of the rotor hub  8 . Furthermore the wall element  27  comprises a window-like opening  28 , through which the inner chamber  26  of the rotor blade  10  can be accessed from the rotor hub  8 . The blade angle adjustment drive  14  engages on the wall element  27 , and is of identical construction to the blade angle adjustment drive  13 , so that hereinafter the blade angle adjustment drives will be described in more detail with reference to the blade angle adjustment drive  13 . 
     The blade angle adjustment drive  13  is illustrated in  FIG. 3 , in which the motor  21  is coupled via its motor shaft  29  to the drive side of the transmission  22 , whose drive side is coupled in turn to a coupling shaft  30 . The coupling shaft  30  is connected in a torque-resistant manner to a threaded spindle  31 , onto which a spindle nut  32  is screwed. The spindle nut  32  is securely connected to an actuating member  33 , which is rotatably mounted on the rotor hub  8  at its end  34  facing away from the spindle nut  32 . The linear adjustment member  23  thus comprises the threaded spindle  31 , the spindle nut  32  and the actuating member  33 . The coupling shaft  30  is preferably also included in the adjustment member  23 . 
     The threaded spindle  31  is detachably connected to the coupling shaft  30  via fastening means  35 , which are formed in this case as bolts. Furthermore the spindle nut  32  is detachably connected to the actuating member  33  via a fastening means  36 , which is formed in this case as a bolt. The sub-assembly formed by the threaded spindle  31  and the spindle nut  32  can thus be replaced without having to dismantle the whole angle adjustment drive  13  or relatively large parts thereof. 
     The threaded spindle  31  and the spindle nut  32  are arranged in a housing  37 , on which the actuating member  33  can be displaceably guided in the direction of the longitudinal axis  38  of the threaded spindle  31 . Furthermore the coupling shaft  30  is rotatably mound on the housing  37  about the longitudinal axis  38 . The housing  37 , which overall is formed as a closed unit, comprises a removable cover  39  (see  FIG. 2 ), by means of which an access opening to the inner chamber of the housing  37  can be exposed, so that the sub-assembly formed from the threaded spindle  31  and the spindle nut  32  can be accessed. The housing  37  is in particular counted as part of the adjustment member  23 . 
     The blade angle adjustment drive  13  is formed as a threaded spindle mechanism, which on the one hand is linked via the end  34  of the actuating member  33  to the rotor hub  8  and on the other hand is linked via the housing  40  of the transmission  22  to the wall element  19 . By rotating the threaded spindle  31  about its longitudinal axis  38  the threaded spindle  31  is moved in the direction of or in the opposite direction to the arrow  46  relative to the actuating member  33 . Together with the threaded spindle  31 , the transmission  22  and the drive  21  thus also move in the direction of or in the opposite direction to the arrow  46 . Since the wall element  19  is connected in a torque-resistant manner to the rotor blade  9 , as a result of this movement the rotor blade  9  is rotated relative to the rotor hub  8  about its blade axis  11  in the direction of or in the opposite direction to the arrow  47 . 
     A partial side view of the blade angle adjustment drive  13  is shown in  FIG. 4 , in which the end  34  of the actuating member  33  is mounted by means of a linkage  41  on the rotor hub  8 . The linkage  41  allows a swivelling movement of the actuating member  33  about a swivel axis  42 , which runs parallel to the blade axis  11 . The linkage  41  is formed for example as a pivot joint, as a universal or Cardan joint, as a ball-and-socket joint or as an elastomeric bearing. Since the adjustment member  23  on account of its length passes through the wall of the rotor hub  8  and is mounted outside the rotor hub  8  on this, the wall of the rotor hub  8  has a longitudinal slit  48  (see  FIG. 2 ) through which the adjustment member  23  extends. The longitudinal slit  48  permits a swivelling of the adjustment member  23  about the swivel axis  42 . 
     Another partial side view of the blade angle adjustment drive is shown in  FIG. 5 , in which the housing  40  of the transmission  22  is rotatably mounted on the wall element  19  about a swivel axis  50  by means of a linkage  49 . The swivel axis  50  runs parallel to the blade axis  11 . Although the linkage  49  in this case forms an elastomeric bearing, the linkage  49  can also be formed as a pivot joint, a universal joint or as a ball-and-socket joint. 
     A partial sectional view of the transmission  22  is shown in  FIG. 6 , in which the motor shaft  29  is connected in a torque-resistant manner to a toothed gear  43 , which meshes with a toothed gear  44  that is connected in a torque-resistant manner to the coupling shaft  30 . In this case the motor shaft  29  runs parallel to the coupling shaft  30  and to the threaded spindle  31 . 
     Further embodiments of the invention are shown in  FIGS. 7 and 8 , in which features identical or similar to those of the first embodiment are identified by the same reference numerals as in the first embodiment. 
       FIG. 7  shows a partial sectional view of a transmission  22  according to a second embodiment of the invention, in which the motor shaft  29  runs perpendicular to the coupling shaft  30  and to the threaded spindle  31 , and in which the two toothed gears  43  and  44  are respectively formed as a bevel gear. Due to this configuration of the transmission  22  another arrangement of the electric motor  21  relative to the adjustment member  23  is also provided. Apart from these differences the second embodiment is however substantially identical to the first embodiment, so that as regards the further description of the second embodiment reference will be made to the description of the first embodiment. 
     A partial sectional representation of a blade angle adjustment drive  13  according to a third embodiment of the invention is shown in  FIG. 8 , in which the transmission  22  and the drive  21  are arranged on different sides of the wall element  19 . In particular the drive  21  is installed in the inner chamber  18  of the rotor blade  9 . Apart from these differences the third embodiment is however substantially identical to the second embodiment, so that as regards the further description of the third embodiment reference will be made to the description of the previous embodiments.