Windmill structure for use in wind power apparatus

Abstract

In order to provide a windmill structure capable of preventing a blade from damage based on a strong wind, the windmill structure is for use in a wind power apparatus in which a dynamo-electric generator is driven by a main shaft to which a rotation of the windmill is transmitted. The windmill comprising at least one blade which extends in a radial direction from a blade supporting portion of a main shaft tip in relation to the main shaft. The windmill structure comprises the blade comprising a fixing portion supported on the blade supporting portion and extending to a radial direction, and a moving portion connected to an upper end of the fixing portion. The moving portion is capable of projecting and retreating from the fixing portion to the radial direction. The windmill structure further comprises control means for changing the projection length of the moving portion in accordance with a wind speed.

1 . A windmill structure for use in a wind power apparatus in which a dynamo-electric generator is driven by a main shaft to which a rotation of a windmill is transmitted, said windmill comprising at least one blade which extends in a radial direction from a blade supporting portion of a main shaft tip in relation to said main shaft, wherein said windmill structure comprises: 
 said blade comprising a fixing portion supported on said blade supporting portion and extending to a radial direction, and a moving portion connected to an upper end of said fixing portion, said moving portion being capable of projecting and retreating from said fixing portion to the radial direction; and    control means for changing the projection length of said moving portion in accordance with a wind speed.    
     
     
         2 . A windmill structure for use in a wind power apparatus as claimed in  claim 1 , wherein: 
 said fixing portion comprises a front plate and a rear plate, a cavity portion being formed between said front plate and said rear plate; and    said moving portion being stored in said cavity portion of the fixing portion when said moving portion retreats.    
     
     
         3 . A windmill structure for use in a wind power apparatus as claimed in  claim 1  or  2 , wherein: 
 said control means comprises a male screw rod rotatably supported on said blade supporting portion and extending to the radial direction in said cavity portion of the fixing portion, a sensor for detecting the wind speed, driving means for make said male screw rod rotate in accordance with an output of said sensor, and a female screw plate fixed on said moving portion and screwed into said male screw rod; and    said female screw plate moving along said male screw rod on the basis of the rotation of said male screw rod so that the projection length of said moving portion is changed in accordance with the wind speed.    
     
     
         4 . A windmill structure for use in a wind power apparatus as claimed in any one of  claims 1  to  3 , wherein: 
 said windmill structure comprises a bearing mounted on said fixing portion and a rail mounted on said moving portion, said rail being fitted into said bearing; and    said rail moving with said rail being fitted into said bearing when said moving portion projects and retreats.