Marine propeller applicable to all speed ranges

Abstract

An all speed range propeller includes a propeller hub and plural propeller blades having their shafts symmetrically connected with the propeller hub. Each propeller blade is divided into a first region and a second region from the propeller hub to an outer end. The first region and the second region are different in wing structure, and the wing cross-sectional area of the second region is smaller than that of the first region. Thus, in speed ranges that common ships navigate most frequently, the all speed range propeller of this invention can lower the influence of cavitation produced because of different speed ranges, able to maintain high efficiency in use and prevent the efficiency of the propeller from lowered exceedingly.

What is claimed is: 
     
         1 . An all speed range propeller comprising a propeller hub and a plurality of propeller blades, said propeller blades having their shafts symmetrically connected with said propeller hub, each said propeller blade having an upper surface and a lower surface, said upper surface and said lower surface having a junction of their front half section formed into a wing front edge, said upper surface and said lower surface having a junction of their rear half section formed into a wing rear edge; and characterized by,
 each said propeller blade divided into a first region and a second region in a direction from said propeller hub to an outer end, said first region and said second region different in wing structure and said each said propeller blade radially combined on said propeller hub, wing cross-sectional area of said second region smaller than that of said first region, in speed ranges that common ships navigate most frequently said all speed range propeller able to lower influence of cavitation produced due to different speed ranges, said all speed range propeller able to maintain high efficiency in use when operated in different speed ranges.   
     
     
         2 . The all speed range propeller as claimed in  claim 1 , wherein said upper surface of said first region is formed with an upper convex portion extending from said wing front edge to said wing rear edge while a rear half section of said lower surface of said first region is formed with a lower convex portion stretching toward said wing rear edge, and said upper surface and said lower surface of said second region are formed with at least one concave portion. 
     
     
         3 . The all speed range propeller as claimed in  claim 1 , wherein a front half section of said upper surface of said second region is formed with an upper even-smooth portion and a rear half section is formed with an upper concave portion extending toward said wing rear edge, a front half section of said lower surface of said second region formed with a lower even-smooth portion, a rear half section of said lower surface of said second region formed with a lower convex portion extending toward said wing rear edge. 
     
     
         4 . The all speed range propeller as claimed in  claim 2 , wherein a rear half section of said upper surface of said second region is formed with an upper concave portion stretching toward said wing rear edge and a front half section of said lower surface of said second region is formed with a lower concave portion extending toward said wing rear edge, letting said second region generally formed into a S-shaped wing structure. 
     
     
         5 . The all speed range propeller as claimed in  claim 1 , wherein each said propeller blade is further formed with a central region having an upper surface and a lower surface connected between said first region and said second region with great curvature change. 
     
     
         6 . An all speed range propeller comprising a propeller hub and plural propeller blades having their shafts symmetrically connected with said propeller hub, each said propeller blade having an upper surface and a lower surface, said upper surface and said lower surface having a junction location of their front half section formed into a wing front edge, said upper surface and said lower surface having a junction location of their rear half section formed into a wing rear edge; and characterized by,
 each said propeller blade divided into a first region and a second region from said propeller hub to an outer end, said first region and said second region different in wing structure, said propeller blades radially combined with said propeller hub, wing cross-sectional area of said second region being smaller than that of said first region, said upper surface of said first region of said all speed range propeller having a location adjacent to said wing rear edge defined to be an upper apex, said lower surface of said first region having a location adjacent to said wing rear edge defined to be a lower apex, cavitation bubbles formed at said upper apex and said lower apex of said first region when said all speed range propeller is rotated at intermediate and high speed ranges, said cavitation bubbles formed into a cavitation bubble area stretching toward said wing rear edge, said upper surface of said second region having a location adjacent to said wing rear edge defined to be a lower convex surface where cavitation bubbles are formed, said cavitation bubbles formed into a cavitation bubble area stretching toward said wing rear edge.   
     
     
         7 . An all speed range propeller comprising a propeller hub and plural propeller blades that have their shafts symmetrically connected with said propeller hub, each said propeller blade having an upper surface and a lower surface, said upper surface and said lower surface having a junction of their front half section formed into a wing front edge, said upper surface and said lower surface having a junction location of their rear half section formed into a wing rear edge; and characterized by,
 each said propeller blade divided into a first region and a second region from said propeller hub to an outer end, said first region and said second region different in wing structure, said propeller blades radially combined with said propeller hub, wing cross-sectional area of said second region smaller than that of said first region, lift coefficient of a unit area of each said propeller blade becoming great when said all speed range propeller is rotated at low and intermediate speed ranges, able to lessen area of each said propeller blade.