Abstract:
“The invention relates to a nacelle including releasable attachment means being adapted for suspension of the nacelle between at least two wheel sets as completely or partly self-supporting suspension.”

Description:
[0001]     The present invention relates to a wind turbine nacelle. The invention relates to a vehicle according to claim  1 , a nacelle according to claim  10 , a transportation method according to claim  15  and a loading method according to claim  17 .  
       BACKGROUND OF THE INVENTION  
       [0002]     Typically, wind turbine nacelles are transported to the mounting site by means of large trucks capable of carrying the relevant load.  
       SUMMARY OF THE INVENTION  
       [0003]     The invention relates to a vehicle comprising at least two wheel sets and at least one nacelle, said nacelle being suspended between said at least two wheel sets.  
         [0004]     According to the invention, several advantages may be obtained by suspending a nacelle between at least two wheel sets.  
         [0005]     One advantage is that the complete vertical extension of the vehicle may be reduced compared to traditional nacelle transportation setups due to the fact that the frame structure of the nacelle forms part of the complete vehicle. Moreover, advantageous logistics may be obtained due to the fact that the vehicle may be reduced to comprising two relatively short bogies once a nacelle has been delivered at the delivery site. Therefore, further transportation of the wheel sets may be performed without escort and special route planning.  
         [0006]     When, at least one of said wheel sets forms a trailer, a further advantageous embodiment of the invention has been obtained.  
         [0007]     According to the invention, the vehicle may advantageously comprise standard transportation components, such as trailers suitable for other transportation purposes.  
         [0008]     Typically, the trailers may be pulled by a suitable truck.  
         [0009]     According to an embodiment of the invention, the wheel sets may be self-propelled.  
         [0010]     According to the invention, the at least one wheel set may e.g. be comprised by a truck or the like.  
         [0011]     When at least one of said wheel sets comprises elevation means, a further advantageous embodiment of the invention has been obtained.  
         [0012]     The elevation means may advantageously be comprised in the wheel sets as integrated hydraulic leveling means.  
         [0013]     The elevation means may advantageously be hydraulic.  
         [0014]     When said lifting means is integrated in the wheel sets, a further advantageous embodiment of the invention has been obtained.  
         [0015]     When said vehicle comprises moment-absorbing attachment means, a further advantageous embodiment of the invention has been obtained.  
         [0016]     The moment-absorbing attachment means may e.g. be established for force equalization on the axles of a wheel set, thereby facilitating suspension of even very heavy nacelles between the wheel sets. In other words, the nacelle may be lowered so much that it more or less defines the complete vertical extension of the vehicle, only supplemented by the vertical extension of a small security distance gap between the nacelle and the ground surface.  
         [0017]     The moment-absorbing means may be established as static mechanical structures or advantageously be means of dynamic moment-absorbing means.  
         [0018]     When said moment-absorbing attachment means comprises variable moment-absorbing attachment means, a further advantageous embodiment of the invention has been obtained.  
         [0019]     Examples of such moment-absorbing means may be established by means of hydraulic moment-absorbing means capable of e.g. providing a fixed moment during transport of the nacelle.  
         [0020]     When said moment attachment means comprises the hub of the nacelle, a further advantageous embodiment of the invention has been obtained.  
         [0021]     According to the invention, the hub of a nacelle may advantageously be applied for transferring forces from the nacelle to the wheel set.  
         [0022]     When using at least two vehicles as defined above for transportation of at least one nacelle, a further advantageous embodiment of the invention has been obtained.  
         [0023]     Moreover, the invention relates to a nacelle comprising releasable attachment means, said attachment means being adapted for suspension of said nacelle between at least two wheel sets as completely or partly self-supporting suspension.  
         [0024]     According to the invention, the nacelle may in principle form part of the constructive members of a transportation vehicle. Evidently, such nacelle must necessarily be constructed in a way so that it can absorb the forces affecting the nacelle structure during both transportation, and of course, use at the final destination as a wind turbine nacelle.  
         [0025]     When said nacelle is self-supporting between said attachment means, a further advantageous embodiment of the invention has been obtained.  
         [0026]     When applying a completely self-supporting frame structure to the nacelle, additional frame reinforcement may be avoided during transportation.  
         [0027]     When said attachment means comprises at least two attachment arrangements, a further advantageous embodiment of the invention has been obtained.  
         [0028]     According to the invention, discrete point attachment may be applied. In particular, four-point attachment may be obtained.  
         [0029]     Evidently, several other suitable attachment arrangements may be applied within the scope of the invention as long as they are capable of absorbing the relevant forces, expressed as e.g. vertical and horizontal moment.  
         [0030]     When said attachment means comprises at least one front attachment arrangement and at least one rear attachment arrangement, a further advantageous embodiment of the invention has been obtained.  
         [0031]     When said front attachment comprises at least part of the hub, a further advantageous embodiment of the invention has been obtained.  
         [0032]     According to the invention, the hub of a wind turbine may advantageously be applied as the front attachment arrangement.  
         [0033]     Moreover, the invention relates to a method of transporting at least one wind turbine nacelle provided with at least two wheel sets, and when suspending said at least one wind turbine nacelle between said at least two wheel sets, a further advantageous embodiment of the invention has been obtained.  
         [0034]     When said at least two wheel sets comprise releasable attachment means, and at least one of said releasable attachment means is liftable by means of lifting means, and the at least one wind turbine nacelle is attached to said at least two wheel sets by means of the releasable attachment means, and the nacelle is lifted by means of said at least one attachment arrangement, a further advantageous embodiment of the invention has been obtained.  
         [0035]     Moreover, the invention relates to a method of loading at least one wind turbine nacelle onto a vehicle arrangement comprising at least two wheel sets, and when suspending said at least one wind turbine nacelle between said at least two wheel sets, a further advantageous embodiment of the invention has been obtained.  
     
    
     THE FIGURES  
       [0036]     The invention will be described in detail in the following with reference to the figures, of which  
         [0037]      FIG. 1  illustrates a wind turbine nacelle according to the invention,  
         [0038]      FIGS. 2   a  to  2   d  illustrate the main transportation actions of a nacelle according to the invention,  
         [0039]      FIGS. 3   a  and  3   b  illustrate the details of wind turbine nacelle suspension according to the invention, and  
         [0040]      FIGS. 4   a  to  4   d  illustrate different embodiments of moment-absorbing suspension according to the invention.  
     
    
     DETAILED DESCRIPTION  
       [0041]      FIG. 1  illustrates a cross-section of a wind turbine nacelle according to one embodiment of the invention.  
         [0042]     The illustrated nacelle  20  comprises a basic structure represented by a welded or molded machine frame on which the main structures of the wind turbine are founded or suspended.  
         [0043]     Such main components may e.g. include generator, yaw, rotor shaft, gears, etc.  
         [0044]     According to the invention, the basic structure is provided with at least two mutually displaced engagement arrangements  27  and  71 ,  72 .  
         [0045]     The engagement arrangements  71 ,  72  are either included in or fitted to the basic structure.  
         [0046]      FIGS. 2   a  to  2   d  illustrate the main transport actions demonstrating logistic features of an advantageous embodiment of the invention.  
         [0047]      FIG. 2   a  illustrates two wheel sets according to the invention.  
         [0048]     The wheel sets comprise attachment precautions, which are described below.  
         [0049]     The wheel sets are basically modular trailers  21 ,  22 . The trailers  21 ,  22  comprise means, e.g. hydraulic means (not shown) for lowering or raising the wheels.  
         [0050]     The trailer  21  comprises one attachment arrangement  24  and the trailer  22  comprises another attachment arrangement  25 .  
         [0051]     In  FIG. 2   b , the wheels of the trailers  21 ,  22  have been raised so that the carrier has been lowered. Then, the trailers have been positioned in relation to a nacelle  20 , facilitating fixed attachment of the trailer to the carrier  21 ,  22 .  
         [0052]     In  FIG. 2   c , the trailers have been raised by lowering the wheels of the trailers and the nacelle  20  has been lifted from the ground.  
         [0053]     Subsequently, the trailers  21 ,  22  and the nacelle  20  constitute a combined vehicle, which may be pulled by e.g. a truck  23  or other kinds of suitably powered vehicles.  
         [0054]     Moreover, the illustrated vehicle is mounted with a sub-cover  28  adapted for protecting the sub-portion of the nacelle  20  against scratches etc. during transport.  
         [0055]      FIG. 2   d  illustrates the trailers  21 ,  22  that have now been unloaded, typically by lowering the trailers  21 ,  22 , detaching the nacelle  20  and removing the trailers  21 ,  22  from the nacelle  20 .  
         [0056]     Now the trailers  21 ,  22  may be mutually coupled thereby forming one combined trailer, which may be transported by e.g. truck.  
         [0057]     In other words,  FIG. 2   b  illustrates a trailer made up by two trailers  21 ,  22  and a nacelle  20  in combination, while the trailer in  FIG. 2   d  basically illustrates a new trailer formed by the trailers  21 ,  22 .  
         [0058]     An important aspect of this fact is that the new trailer may now be formed by two relatively short trailers  21 ,  22 . Therefore, the new trailer may typically form part of a vehicle, e.g. including truck having a length of less than e.g.  18  meters. This means that the homebound (return) transportation of the trailers  21 ,  22  may be a simple operation, which may be performed without escort and requirements for numerous different transport applications, permissions etc. by the relevant authorities.  
         [0059]     It should be noted that the above-described preferred embodiment of the invention features an “onboard lift”. Evidently, the loading of the nacelle onto the trailers may be performed by means of a traditional external lift, although the preferred load/unload procedure is performed by means of lifting means integrated in the trailer or trailers.  
         [0060]      FIG. 3   a  illustrates some advantageous features of the above-described embodiment of the invention with respect to force distribution and orientation.  
         [0061]     The illustration illustrates the principle mechanical attachment of the rear part of the nacelle  20  to the trailer  22 .  
         [0062]     Basically, the nacelle  20  comprises a rear attachment arrangement. According to the illustrated embodiment, the rear attachment comprises four attachment members  71 ,  72 , of which only two are shown in a cross-section, one on each side of the rear part of the nacelle  20 . The attachment members  71 ,  72  are fitted to or comprised in the main frame  10  of the nacelle  20 .  
         [0063]     The attachment members facilitate mechanical four-point coupling of the main frame to the attachment arrangement  25  of the trailer  22 , which creates absorption of moment both in the vertical and horizontal direction.  
         [0064]     The trailer  22  comprises an attachment arrangement  301  fitted with attachment fittings  302 ,  303  attachable to the aforementioned attachment means  71 ,  72 .  
         [0065]     A hydraulic arrangement  304  forms part of the attachment arrangement. The hydraulic arrangement  304  is capable of evening out force exercised on the axles of the trailer  22 .  
         [0066]     Moreover, the hydraulic arrangement  304  may advantageously be applied for absorbing moment variation by means of suitable measuring and control equipment not shown.  
         [0067]     In this way, suspension of the nacelle  20  by the above-described attachment arrangement may absorb high moment and be able to transfer force F to the axles of the trailer  22  in such a way that the resulting force F exercised on the axles is relatively uniform.  
         [0068]     Evidently, according to the invention, the main frame  10  of the nacelle  20  should be dimensioned in such a way that it is able to absorb the moment transferred from the attachment arrangement, alone or in combination with other attachment arrangements, e.g. a front attachment arrangement.  
         [0069]      FIG. 3   b  illustrates some advantageous features of the above-described embodiment of the invention with respect to force distribution and orientation.  
         [0070]     The illustration illustrates the principle mechanical attachment of the front part of the nacelle  20  to the trailer  21 .  
         [0071]     Basically, the main functionality of the illustrated suspension is the same as that of the above-described suspension, i.e. to even out force exercised on the axles of the trailer  21  as much as possible.  
         [0072]     However, the illustrated suspension is obtained by suspending the nacelle  20  to an attachment arrangement  24  on the trailer  21 . The attachment arrangement  24  receives an attachment arrangement of the nacelle  20 , here comprised by the hub  27  of the nacelle  20 .  
         [0073]     Again, the hub  27  must be able to absorb the induced moment in combination with the main frame of the nacelle  20 .  
         [0074]     It should be noted that it is a condition, according the above-illustrated embodiment of the invention, that the relevant part of the mechanical structure of the nacelle  20  is self-sustaining.  
         [0075]      FIG. 4  basically illustrates the moment absorbed by suspension according to the invention. Again, the suspension should feature the ability to absorb a suitably high moment in order to even out force F exercised on the trailer axles.  
         [0076]      FIGS. 5   a ,  6   a  and  7   a  illustrate the principles of different preferred suspension arrangements according to the different embodiments of the invention.  
         [0077]      FIGS. 5   b ,  6   b  and  7   b  illustrate different applicable combinations of suspension arrangements according to the invention.  
         [0078]     Evidently, several other combinations may be applied within the scope of the invention than the three-point and four-point suspensions mentioned below.  
         [0079]      FIG. 5   a  illustrates the cross-section of discrete point suspension according to one embodiment of the invention. Here, suspension is supplemented by further discrete point suspension in the plane.  
         [0080]     Basically,  FIG. 5   a  illustrates suspension of a nacelle part  52  to a trailer part  51 .  
         [0081]     The illustrated suspension is established by suspension of discrete points  53 ,  54 ,  55  in one cross-section.  
         [0082]     The force F directed to the points  53 ,  54  is transferred by means of a moment absorbing arrangement, here comprised by a hydraulic cylinder  56 .  
         [0083]      FIG. 5   b  illustrates four-point suspension of a nacelle as illustrated and explained in  FIG. 5   a  seen from above.  
         [0084]     Please note that the illustrated rear suspension principally comprises two of the above-described arrangements.  
         [0085]     Evidently, in this context, four-point suspension refers to suspension in which a nacelle is basically attached to four areas when seen from above (i.e. not necessarily four points exclusively).  
         [0086]     Thus, the illustrated four-point suspension is basically capable of absorbing moment as illustrated in  FIG. 5   a , i.e. a gravity force distribution arrangement. In addition, it is also capable of absorbing moment in the transverse direction, as illustrated in  FIG. 5   b.    
         [0087]      FIG. 6   a  illustrates the cross-section of a rigid moment-absorbing arrangement  63 .  
         [0088]     Here, rigid suspension is established between a nacelle part  62  and a trailer part  61  by means of a rigid mechanical construction  63 .  
         [0089]     Again,  6   b  illustrates suspension of a nacelle as illustrated and explained in  FIG. 6   a  when seen from above, i.e. here by means of two rigid moment-absorbing arrangements  63  capable of absorbing suspension moment in both the vertical and horizontal direction.  
         [0090]     Numerous moment-absorbing suspensions are applicable within the scope of the invention.  
         [0091]      FIG. 7   a  illustrates a further embodiment of the invention, here more or less corresponding to the hub suspension illustrated in  FIGS. 2   a - d  and  FIGS. 3   a - b.    
         [0092]     Here, a nacelle part  72  is suspended to a trailer part  71 .  
         [0093]     The trailer part  71  is mounted with a hub receiving arrangement  74 , to which the hub  73  of a wind turbine nacelle  72  is attached e.g. by bolts in the points  75 .  
         [0094]     When displacing the attachment members mutually  75 , it will be possible to transfer attachment forces via a moment conversion arrangement arranged on the trailer.  
         [0095]     According to the invention, the moment conversion arrangement facilitates distribution of force on the trailer axles in a more homogeneous manner. Hence, force exercised on the axles of a trailer in which the nacelle is suspended may be uniformly or at least relatively uniformly distributed on the axles of the trailer.  
         [0096]      FIG. 7   b  may also be referred to as three-point suspension (with respect to horizontal moment force).  
         [0097]     Basically,  FIG. 7  illustrates a “three-point” suspension, wherein a hub  73  comprises part of a front-moment absorbing arrangement and wherein two hydraulic cylinders  56  comprise part of a rear-moment absorbing arrangement.