Dc motor type fuel pump

Abstract

A dc motor fuel pump pressurizes and outputs fuel at a pump section ( 20 ) fixed to a yoke ( 3 ) of a motor section ( 10 ) accompanied by drive of a dc motor of mentioned motor section ( 10 ). The yoke ( 3 ) includes a first tubular yoke ( 4 ) provided with a ring-shaped magnet ( 2 ) of rare earths on an inner circumference and a second tubular yoke ( 5 ) provided on an outer circumference of the first tubular yoke ( 4 ) at a position conforming to the magnet. ( 2 ).

1 . A dc motor fuel pump that pressurizes and outputs fuel at a pump section fixed to a yoke of a motor section accompanied by drive of a dc motor of mentioned motor section; the dc motor fuel pump being characterized in that said yoke comprises a first tubular yoke provided with a ring-shaped magnet of rare earths on an inner circumference and a second tubular yoke provided on an outer circumference of said first tubular yoke at a position conforming to said magnet.  
   
   
       2 . The dc motor fuel pump according to  claim 1 , wherein said magnet is formed by injection molding, and a gate portion thereof is formed at an end face of said magnet.  
   
   
       3 . The dc motor fuel pump according to  claim 1 , wherein said magnet is provided with a convex portion or a concave portion at an end face thereof, and said convex portion or concave portion engages with a concave portion or a convex portion of the other member fixed to said yoke.  
   
   
       4 . The dc motor fuel pump according to  claim 3 , wherein the convex portion of said magnet is a gate portion for the injection molding.  
   
   
       5 . The dc motor fuel pump according to  claim 1 , wherein at least one end face of said first tubular yoke and said magnet is on the same plane.  
   
   
       6 . The dc motor fuel pump according to  claim 1 , wherein an axial length of said first tubular yoke is substantially equal to an axial length of said magnet.  
   
   
       7 . The dc motor fuel pump according to  claim 1 , wherein said magnet is formed by injection molding, and said first tubular yoke is 3 mm in thickness.