Abstract:
A cowling of the invention includes a cover body and an empennage connected with the cover body. The cover body includes an accommodating space for receiving an impeller, and a first opening serving as an air inlet for the impeller. According to the wind direction, the empennage will adjust the first opening to the proper position to face the wind.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a cowling, and in particular, to a cowling for a wind power generator. 
     2. Description of the Related Art 
     An impeller of a conventional wind power generator is driven by wind to generate electric power. Wind, however, blows in all directions. If the wind does not blow directly on the impeller, the wind power generator can not operate at optimum efficiency. Another impeller of a conventional wind power generator changes direction corresponding to wind direction. When the turbulence occurs, the impeller loads wind force in all directions, the potential damage causes to the wind power generator. 
     The invention provides a cowling applicable to any kind of impeller for wind power generators, capable of effectively solving the described problems. 
     BRIEF SUMMARY OF INVENTION 
     The invention provides a cowling for a wind power generator. The cowling rotates to face the wind according to wind direction, avoiding impeller load due to multidirectional wind force thus protecting the impeller. 
     The cowling of the invention includes a cover body and an empennage connected with the cover body. The cover body includes an accommodating space for receiving an impeller, and a first opening serving as an air inlet for the impeller. According to the wind direction, the empennage will adjust the first opening to the proper position to face the wind. 
     If the wind is a multidirectional and turbulent, the cowling can be positioned to provide a single direction for channeling the multidirectional turbulence through the impeller from the first opening and drive to the impeller. The cover body blocks turbulence from entering the cowling from a direction interfering with the impeller. Thus, the impeller works efficiently and the lifespan of the impeller is prolonged. 
     A detailed description is given in the following embodiments with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
         FIG. 1  shows an embodiment of a cowling of the invention; 
         FIG. 2  is a schematic view in a different view angle of the cowling shown in  FIG. 1 ; 
         FIG. 3  is a front view of a cowling applied to a wind power generator of the invention; 
         FIG. 4  is a cross-sectional view of the cowling shown in  FIG. 3 ; 
         FIGS. 5 to 7  are schematic views to show all kinds of empennages; 
         FIG. 8  is a schematic view of another embodiment of a cowling of the invention; 
         FIG. 9  is a schematic view of another embodiment of a cowling of the invention; 
         FIG. 10  is a schematic view to show a first opening of a cowling facing side of an impeller; 
         FIG. 11  is a front view the cowling shown in  FIG. 10 . 
     
    
    
     DETAILED DESCRIPTION OF INVENTION 
     The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope df the invention is best determined by reference to the appended claims. 
     Referring to  FIGS. 1 to 3 , a cowling  1  of the invention comprises a cover body  10  and an empennage  121  connected to the cover body  10  by the connecting parts  12 . The cover body  10  comprises an accommodating space  101  and a first opening  103 . The accommodating space  101  is communicated to the first opening  103 . An impeller  2  for generating electric power is disposed in the accommodating space  101 . The first opening  103  is located at one side of the cover body  10  and has an air inlet for transmission of the wind. The position of the connecting part  12  is located at the side of the cover body  10  opposite to the first opening  103 . The empennage  121  can be adjusted by the wind so the first opening  103  faces the blowing wind. In this embodiment, the first opening  103  is a rectangle and the empennage  121  is a circle. 
     Referring to  FIG. 4 , in detail, the impeller  2  further comprises a shaft  21  passing through the center of the impeller  2 . The cowling  1  is supported by the shaft  21  via two bearings  22 , thus, when the impeller  2  rotates, the cowling  1  can simultaneously rotate without interference. 
     Note that shape of the empennage  121  is not limited. The empennage  121  may be rhombus, polygon, T-shape of fin shape shown in  FIGS. 5 to 7 . The empennage  121  can be any other shape enabling the cowling  1  to change direction. 
     The cover body  10  of the cowling  1  further comprises a second opening  105  shown in  FIG. 2  opposite to the first opening  103 . After the wind passes through the impeller  2 , airflow exits from an air outlet, e.g. the second opening  105 , to prevent interference between the wind and the airflow. 
     If the wind is multidirectional turbulence, the empennage  121  rotates along one direction of the multidirectional turbulence. Thus, the first opening  103  of the cowling  1  is adjusted to a stable position so that the first opening  103  faces the wind. One direction of the multidirectional turbulence can pass through the impeller  2  from the first opening  103  to drive the impeller  2 . The cover body  10  blocks turbulent wind from other directions entering the cowling  1  and interfering with the impeller  2 . Thus, the impeller  2  works efficiently and the lifespan of the impeller  2  is prolonged. 
       FIG. 8  shows another embodiment of the invention. Compared with  FIG. 1 , the first opening  303  of the cowling  3  is a bell shape for enlarging the area of the air inlet and concentrating the wind to drive the impeller. 
     Referring to  FIG. 9 , the cowling  3  further comprises a plurality of air-guiding elements  305  installed in the first opening  303  shown in  FIG. 8  for adjusting the wind. Thus, the impeller  2  works efficiently. 
     Moreover, the first openings can be located corresponding to one side of the impeller shown in  FIGS. 10 to 11 . Compared with  FIG. 1 , the first opening  403  of the cowling  4  does not correspondingly face the impeller  2 , but faces the side of the impeller  2 . In another word, the first opening  403  faces one side of the blades of the impeller  2 . Thus, after entering the first opening, the wind directly drives the blades, thus increasing efficiency. 
     While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.