Rotor of brushless direct-current motor

Abstract

A permanent magnet rotor of a brushless direct current (BLDC) motor, in which cogging torque ripple and electromagnetic vibration noise transferred to the permanent magnet rotor can be blocked and a motor's power-to-weight ratio can be improved. A conventional BLDC motor has to use an electric steel sheet core so as to maintain the maximum magnetic flux density of the permanent magnet rotor and to minimize a rotating electric field loss. As a result, cogging torque vibration is unavoidably transferred to a load side through the motor rotary shaft. However, the rotor can enable stable driving of the BLDC motor by innovatively blocking the cogging torque vibration and the electromagnetic vibration noise and can greatly reduce the motor's weight by using a plastic or non-magnetic material instead of an electric steel sheet core.

1 . A rotor of a BLDC (brushless direct current) motor, comprising:
 a polar anisotropic permanent magnet for allowing a magnetized magnetic path to run therethrough;   a high-strength core portion mounted on the inner side of the polar anisotropic permanent magnet; and   a sound-absorbing resin portion mounted on the inner side of the high-strength core portion.   
   
   
       2 . The rotor of the BLDC motor according to  claim 1 , wherein the thickness of the high-strength core portion is 40-100% of that of the polar anisotropic permanent magnet. 
   
   
       3 . The rotor of the BLDC motor according to  claim 1 , wherein the high-strength core portion is formed of any one of non-magnetic metal, aluminum having a low thermal expansion coefficient, alloy, or high-strength engineering plastic. 
   
   
       4 . The rotor of the BLDC motor according to  claim 1 , wherein the sound-absorbing resin is made of a rubber or a silicon resin. 
   
   
       5 . The rotor of the BLDC motor according to  claim 1 , wherein the polar anisotropic permanent magnetic is formed in a single body. 
   
   
       6 . The rotor of the BLDC motor according to  claim 1 , wherein the polar anisotropic permanent magnetic is cylindrical shape. 
   
   
       7 . A rotor of a BLDC (brushless direct current) motor, comprising:
 a cylindrical permanent magnet for allowing a magnetized magnetic path to run therethrough;   a high-strength core portion mounted on the inner side of the cylindrical permanent magnet; and   a sound-absorbing resin portion mounted on the inner side of the high-strength core portion.   
   
   
       8 . The rotator of a BLDC motor, wherein the cylindrical permanent-magnetic is a polar anisotropic permanent-magnetic. 
   
   
       9 . The rotator of a BLDC motor, wherein the high-strength core portion is formed of any one of non-magnetic metal, aluminum having a low thermal expansion coefficient, alloy, or high-strength engineering plastic 
   
   
       10 . The rotator of a BLDC motor, wherein the sound-absorbing resin portion is made of any one of a rubber and a silicon resin. 
   
   
       11 . A brushless direct current (BLDC) motor, the motor comprises the rotor of  claim 1 . 
   
   
       12 . A brushless direct current (BLDC) motor, the motor comprises the rotor of  claim 7 . 
   
   
       13 . A rotor of a brushless direct current motor, comprising:
 a magnet with rotor flux flow completely inside the magnet; and   a vibration blocking core.