Fan motor

Abstract

A fan motor may include a rotor part having a drive magnet, and a stator part having a drive coil and rotatably holding the rotor part. The rotor part may include a rotor yoke to which the drive magnet is fixed on an inner peripheral side of the rotor yoke, an impeller which is provided with a plurality of blades and which is disposed on an outer peripheral side of the rotor yoke, and a hub for fixing the impeller. The impeller is provided with a held part which is sandwiched between and held by the rotor yoke and the hub in an axial direction. The held part is abutted with an upper face of a bottom part of the rotor yoke and a lower face of a plate part of the hub, and the held part is held by the rotor yoke and the hub in the axial direction

1 . A fan motor comprising:
 a rotor part which includes a drive magnet; and   a stator part which includes a drive coil and which rotatably holds the rotor part;   wherein the rotor part comprises;
 a rotor yoke to which the drive magnet is fixed on an inner peripheral side of the rotor yoke; 
 an impeller which is provided with a plurality of blades and which is disposed on an outer peripheral side of the rotor yoke; and 
 a hub for fixing the impeller; 
 wherein the impeller is provided with a held part which is sandwiched between and held by the rotor yoke and the hub in an axial direction. 
   
     
     
         2 . The fan motor according to  claim 1 , wherein
 the rotor yoke is formed in a bottomed cylindrical shape having a bottom part,   the hub is provided with a plate part, and   the held part is abutted with an upper face of the bottom part of the rotor yoke and a lower face of the plate part of the hub, and the held part is sandwiched between and held by the rotor yoke and the hub in the axial direction.   
     
     
         3 . The fan motor according to  claim 2 , wherein the held part is formed in a flat shape substantially perpendicular to the axial direction. 
     
     
         4 . The fan motor according to  claim 3 , wherein
 the impeller is formed in a bottomed cylindrical shape having a bottom part,   a step-shaped circular hole which is structured of a large diameter hole that is located on an upper side in the axial direction and a small diameter hole whose diameter is smaller than the large diameter hole and that is located on a lower side in the axial direction is formed at a center of the bottom part of the impeller so as to penetrate in the axial direction, and   the held part is a flat part which is formed between a peripheral face of the large diameter hole and a peripheral face of the small diameter hole and which is sandwiched between and held by the rotor yoke and the hub in a state that an upper face of the bottom part of the rotor yoke is abutted with a lower face of the flat part and a lower face of the plate part of the hub is abutted with an upper face of the flat part.   
     
     
         5 . The fan motor according to  claim 1 , wherein
 the hub is formed with a protruded part protruding toward the rotor yoke in the axial direction,   the held part is formed with an arrangement hole in which the protruded part is disposed,   the rotor yoke is formed with an engaging hole with which the protruded part is engaged,   a tip end of the protruded part which is disposed at an edge of the engaging hole is protruded in the axial direction with respect to the engaging hole and formed as a caulking fixed part with which the hub and the rotor yoke are fixed to each other by caulking, and   the caulking fixed part is fixed to the rotor yoke by caulking.   
     
     
         6 . The fan motor according to  claim 5 , wherein
 the hub is formed with an abutting part which is abutted with the stator part to restrict movement of the rotor part in the axial direction, and   the abutting part is protruded in same direction as the protruded part and protruded in the axial direction with respect to the protruded part.   
     
     
         7 . The fan motor according to  claim 5 , wherein the tip end of the protruded part is a projecting part which is formed in a cylindrical shape and a tip end of the projecting part is used as the caulking fixed part. 
     
     
         8 . The fan motor according to  claim 1 , wherein
 the rotor yoke is formed in a bottomed cylindrical shape,   a protruded part which is formed in a substantially cylindrical shape is formed at a center of the hub so as to protrude in the axial direction toward the rotor yoke,   a center of the held part is formed with a circular arrangement hole in which the protruded part is disposed,   a center of a bottom part of the rotor yoke is formed with a circular engaging hole with which the protruded part is engaged,   the protruded part is press-fitted to the engaging hole and abutted with a peripheral face of the engaging hole, and   the rotor yoke and the hub are positioned with an outer peripheral face of the protruded part and a peripheral face of the engaging hole as reference.   
     
     
         9 . The fan motor according to  claim 8 , wherein
 the circular arrangement hole and the circular engaging hole are formed in same diameter, and   the protruded part is press-fitted to the circular arrangement hole and abutted with a peripheral face of the circular arrangement hole.   
     
     
         10 . The fan motor according to  claim 1 , wherein the hub is formed of metal, and a rotation shaft structuring the rotor part is press-fitted and fixed to the hub. 
     
     
         11 . The fan motor according to  claim 1 , further comprising a plurality of ribs which are protruded from at least one of an inner peripheral face of the impeller and an outer peripheral face of the rotor in a radial direction with a predetermined interval,
 wherein the rotor yoke is press-fitted to the impeller so that one of the inner peripheral face of the impeller and the outer peripheral face of the rotor yoke is abutted with end parts in the radial direction of the ribs, and   wherein a gap space is formed between the inner peripheral face of the impeller and the outer peripheral face of the rotor yoke.   
     
     
         12 . The fan motor according to  claim 11 , wherein
 the impeller is formed of resin and formed in a bottomed cylindrical shape,   the rotor yoke is formed in a bottomed cylindrical shape having a bottom part which is abutted with a bottom part of the impeller, and   the rib is formed on the inner peripheral face of the impeller so as to reach at least to a boundary portion between the bottom part of the impeller and the inner peripheral face of the impeller.   
     
     
         13 . The fan motor according to  claim 12 , wherein
 the bottom part of the impeller is formed with radial ribs extending from end parts of the ribs toward a center of the bottom part of the impeller so as to protrude in the axial direction, and   the bottom part of the rotor yoke is abutted with the radial ribs.