Induction motor for drum washing machine and drum washing machine using same

Abstract

An induction motor for a drum washing machine and a drum washing machine using the same are disclosed. An induction motor for a drum washing machine includes: a concentrated winding stator with a plurality of teeth that project from a circumference thereof and a coil wounded around each tooth; a rotor frame connected to a shaft directly fixed to a rotatable drum in the drum washing machine, wherein the concentrated winding stator is located in the rotor frame; and a rotor conductor that generates induced currents in closed circuits along a circumferential direction of the rotor frame when electric currents are applied to the coils so that the rotor frame rotates, wherein the closed circuit is skewed.

1 . An induction motor for a drum washing machine comprising: 
 a concentrated winding stator with a plurality of teeth that project from a circumference thereof and a coil wounded around each tooth;    a rotor frame connected to a shaft directly fixed to a rotatable drum in the drum washing machine, wherein the concentrated winding stator is located in the rotor frame; and    a rotor conductor that generates induced currents in closed circuits along a circumferential direction of the rotor frame when electric currents are applied to the coils so that the rotor frame rotates, wherein the closed circuit is skewed.    
   
   
       2 . The induction motor for a drum washing machine of  claim 1 , further comprising a rotor core on the rotor frame to form a magnetic flux path.  
   
   
       3 . The induction motor for a drum washing machine of  claim 2 , wherein the rotor conductor and the rotor core are formed substantially as one body by die-casting.  
   
   
       4 . The induction motor for a drum washing machine of  claim 1 , wherein the rotor conductor is a plate arranged on an inner surface of the rotor frame along a circumferential direction of the rotor frame.  
   
   
       5 . The induction motor for a drum washing machine of  claim 4 , further comprising a rotor core that has a plate shape between the rotor frame and the rotor conductor to form a magnetic flux path.  
   
   
       6 . The induction motor for a drum washing machine of  claim 1 , wherein a skew distance of each closed circuit is about equal to one pitch of the teeth, wherein the pitch of the teeth is the distance between the centers of adjacent teeth of the stator.  
   
   
       7 . The induction motor for a drum washing machine of  claim 1 , wherein each closed circuit is skewed symmetrically with respect to a center thereof, wherein a skew distance of each closed circuit is in the range of about one to two pitches of the teeth, and wherein the pitch of the teeth is the distance between the centers of adjacent teeth of the stator.  
   
   
       8 . The induction motor for a drum washing machine of  claim 1 , wherein the teeth of the stator include a pole shoe at an end of each tooth that has two opposite sides that project in a circumferential direction relative to the stator to partially cover a space between the teeth of the stator and wherein the two opposite ends are thinner than a central portion of the pole shoe.  
   
   
       9 . The induction motor for a drum washing machine of  claim 1 , further comprising a permanent magnet fixed to the shaft to detect the position of the rotor frame and the rotation speed of the rotor frame.  
   
   
       10 . A drum washing machine comprising: 
 a tub that holds washing solution therein;    a drum that rotates within the tub;    a concentrated winding stator with a plurality of teeth that project from a circumference thereof and a coil wounded around each tooth, the concentrated winding stator fixed to a rear wall of the tub;    a shaft directly connected to the drum, passing through the rear wall of the tub;    a rotor frame directly connected to the shaft, wherein the concentrated winding stator is located in the rotor frame; and    a rotor conductor that generates induced currents in closed circuits along a circumferential direction of the rotor frame when electric currents are applied to the coils so that the rotor frame rotates, wherein the closed circuit is skewed.    
   
   
       11 . The induction motor for a drum washing machine of  claim 10 , further comprising a rotor core on the rotor frame to form a magnetic flux path.  
   
   
       12 . The induction motor for a drum washing machine of  claim 11 , wherein the rotor conductor and the rotor core are formed substantially as one body by die-casting.  
   
   
       13 . The induction motor for a drum washing machine of  claim 10 , wherein the rotor conductor is a plate arranged on an inner surface of the rotor frame along a circumferential direction of the rotor frame.  
   
   
       14 . The induction motor for a drum washing machine of  claim 13 , further comprising a rotor core that has a plate shape between the rotor frame and the rotor conductor to form a magnetic flux path.  
   
   
       15 . The induction motor for a drum washing machine of  claim 10 , wherein a skew distance of each closed circuit is about equal to one pitch of the teeth, wherein the pitch of the teeth is the distance between the centers of adjacent teeth of the stator.  
   
   
       16 . The induction motor for a drum washing machine of  claim 10 , wherein each closed circuit is skewed symmetrically with respect to a center thereof, wherein a skew distance of each closed circuit is in the range of about one to two pitches of the teeth, and wherein the pitch of the teeth is the distance between the centers of adjacent teeth of the stator.  
   
   
       17 . The induction motor for a drum washing machine of  claim 10 , wherein the teeth of the stator include a pole shoe at an end of each tooth that has two opposite sides that project in a circumferential direction relative to the stator to partially cover a space between the teeth of the stator and wherein the two opposite ends are thinner than a central portion of the pole shoe.  
   
   
       18 . The induction motor for a drum washing machine of  claim 10 , further comprising a permanent magnet fixed to the shaft to detect the position of the rotor frame and the rotation speed of the rotor frame.