Brushless motor pump

Abstract

A brushless motor pump includes a case; a motor disposed in the case, and including a rotor and a stator; a rotary blade assembly connected to one end of the rotor; a blade housing mounted to the case and encompassing the rotary blade assembly; an excitation unit for energizing the stator; and a control unit for generating an operating frequency which increases gradually from an initial low value to a constant high value so that the rotor starts to operate at a low speed and continues its operation to a high constant speed.

1 . A brushless motor pump, comprising: 
 a case;    a motor disposed in said case, and including a rotor and a coil unit;    a rotary blade assembly connected to one end of said rotor;    a blade housing mounted to said case and encompassing said rotary blade assembly;    an excitation unit for energizing said coil unit; and    a control unit for generating signals of differing frequencies which increase gradually from an initial low frequency level to a high frequency level so that said rotor starts to operate at a low speed and continues its operation to a high constant speed.    
   
   
       2 . The brushless motor pump of  claim 1 , further comprising a magnetism detector connected to said control unit for producing signals indicative of angular positions of said rotor.  
   
   
       3 . The brushless motor pump of  claim 1 , wherein said stator includes a core of a substantially U-shaped cross-section, said core including two opposite inner walls confining a channel that receives said rotor, said inner walls having opposite recessed surfaces confronting said rotor, each of said recessed surfaces having a shallow region and a deep region, the distance between said shallow region and said rotor being smaller than that between said deep region and said rotor, said shallow regions of said recessed surfaces being arranged substantially at two diametrically opposed positions relative to said rotor, and said deep regions of said recessed surfaces being arranged substantially at two diametrically opposed positions relative to said rotor.  
   
   
       4 . The brushless motor pump of  claim 1 , wherein said rotary blade assembly is mounted on said rotor substantially in a coaxial position.  
   
   
       5 . The brushless motor pump of  claim 4 , wherein said rotary blade assembly is turnable relative to said rotor by an angle of substantially 270 degrees.