Brushless DC motor in washing machine

Abstract

Brushless motor in a washing machine including a stator having a coil coupled to an upper frame, and a rotor having a lower frame entirely formed of a metal to cover an outer circumference and a bottom of the stator, a plurality of magnets fitted to an inside wall of the lower frame at fixed intervals opposite to the coil of the stator, and a support member formed as one unit with, and at a central portion of the lower frame coupled to a washing water shaft for transmission of a rotating force of the lower frame to the washing water shaft, thereby permitting smooth heat dissipation and drainage from the motor, and shortening a fabrication process and time period.

1. A brushless motor in a washing machine, comprising:
 a stator having a coil, the stator coupled to an upper frame; and 
 a rotor having a lower frame entirely formed of a metal to cover an outer circumference and a bottom of the stator, a plurality of magnets fitted to an inside wall of the lower frame at fixed intervals opposite to the coil of the stator, and a support member formed as a single piece with the lower frame at a central portion thereof and coupled to a washing water shaft for transmission of rotating force of the lower frame to the washing water shaft, wherein the lower frame includes a plurality of grooves formed in a bottom surface thereof at fixed intervals along an inside circumference of the bottom surface, each having a drain hole in a bottom of the groove. 
 
     
     
       2. The brushless motor as claimed in  claim 1 , wherein the lower frame further includes a cooling fin between the grooves in the lower frame for dissipation of heat from the stator. 
     
     
       3. The brushless motor as claimed in  claim 1 , wherein the lower frame further includes projections on an inside circumference of the lower frame for fixing intervals of the magnets. 
     
     
       4. The brushless motor as claimed in  claim 1 , wherein a bottom surface of the support member and a surface of the lower frame have a plurality of fastening holes for fastening the support member and the lower frame with fastening means. 
     
     
       5. The brushless motor as claimed in  claim 4 , wherein the fastening means comprise bolts or rivets. 
     
     
       6. The brushless motor as claimed in  claim 1 , wherein the rotor having the lower surface entirely formed of a metal and configured such that the outer circumference of the rotor covers the plurality of magnets fitted to an inside wall thereof serves as the yoke. 
     
     
       7. A brushless motor in a washing machine, comprising:
 a stator having a coil, the stator coupled to an upper frame; and 
 a rotor having a lower frame entirely formed of a metal to cover an outer circumference and a bottom of the stator, a plurality of magnets fitted to an inside wall of the lower frame at fixed intervals opposite to the coil of the stator, and a support member formed as a single piece with the lower frame at a central portion thereof and coupled to a washing water shaft for transmission of rotating force of the lower frame to the washing water shaft, wherein the lower frame includes a plurality of grooves formed in a bottom surface thereof at fixed intervals along an inside circumference of the bottom surface, each having a drain hole in a bottom of the groove, wherein the lower frame her further includes a cooling fin between the grooves in the lower frame for dissipation of heat from the stator, and wherein the cooling fin is formed by lancing the lower frame, which forms a hole which is used as a draft hole. 
 
     
     
       8. A brushless motor in a washing machine, comprising:
 a stator having a coil, the stator coupled to an upper frame; and 
 a rotor having a lower frame entirely formed of a metal to cover an outer circumference and a bottom of the stator, a plurality of magnets fitted to an inside wall of the lower frame at fixed intervals opposite to the coil of the stator, and a support member formed of a single material and as a separate piece from the lower frame, and configured to be attached to the lower frame at a central portion thereof and directly coupled to a washing water shaft for transmission of rotating force of the lower frame to the washing water shaft, wherein the support member is formed of an insulating material that insulates it from the lower frame, and includes:
 a circular rib; 
 radial ribs and reinforcing ribs extending from a circumference of the circular rib for reinforcing the lower frame; and 
 a female serration for coupling the support member with the shaft, wherein the support member includes a plurality of downward coupling projections on a bottom surface thereof, and the lower frame includes a plurality of coupling holes opposite to the coupling projections for accepting the coupling projections on the support member, for coupling the support member and the lower frame. 
 
 
     
     
       9. A brushless motor in a washing machine, comprising:
 a stator having a coil, the stator coupled to an upper frame; and 
 a rotor having a lower frame entirely formed of a metal to cover an outer circumference and a bottom of the stator, a plurality of magnets fitted to an inside wall of the lower frame at fixed intervals opposite to the coil of the stator, and a support member formed at a central portion of the lower frame coupled to a washing water shaft for transmission of rotating force of the lower frame to the washing water shaft, wherein the lower frame further includes a cooling fin between grooves in the lower frame for dissipation of heat from the stator and wherein the cooling fin is formed by lancing the lower frame which forms a hole which is used as a draft hole. 
 
     
     
       10. A brushless motor in a washing machine, comprising:
 a stator having a coil, the stator coupled to an upper frame; and 
 a rotor having a lower frame entirely formed of a metal to cover an outer circumference and a bottom of the stator, a plurality of magnets fitted to an inside wall of the lower frame at fixed intervals opposite to the coil of the stator, and a support member formed at a central portion of the lower frame coupled to a washing water shaft for transmission of rotating force of the lower frame to the washing water shaft, wherein the support member is formed of an insulating material that insulates it from the lower frame, and includes:
 a circular rib; 
 radial ribs and reinforcing ribs extending from a circumference of the circular rib for reinforcing the lower frame; and 
 a female serration for coupling the support member with the shaft, wherein the support member includes a plurality of downward coupling projections on a bottom surface thereof, and the lower frame includes a plurality of coupling holes opposite to the coupling projections for accepting the coupling projections on the support member, for coupling the support member and the lower frame. 
 
 
     
     
       11. A brushless motor in a washing machine, comprising:
 a stator having a coil and coupled to an upper frame; and 
 a rotor having a lower frame entirely formed of metal to cover an outer circumference and a bottom of the stator, and a plurality of magnets fitted to an inside wall of the lower frame at fixed intervals opposite to the coil of the stator, wherein the lower frame further includes a cooling fin formed as a single piece with the rotor for dissipation of heat from the stator and wherein the cooling fin is formed by lancing and bending the lower frame which forms a hole which is used as a draft hole. 
 
     
     
       12. The brushless motor as claimed in  claim 11 , wherein the rotor has a support member formed at a central portion of the lower frame adjacent to the washing water shaft, wherein the lower frame further includes a plurality of grooves formed in a bottom surface of the lower frame at fixed intervals along an inside circumference of the bottom surface. 
     
     
       13. A brushless motor in a washing machine, comprising:
 a stator having a coil, and coupled to an upper frame; and 
 a rotator having a lower frame entirely formed of a metal to cover an outer circumference and a bottom of the stator, and a plurality of magnets fitted to an inside wall of the lower frame at fixed intervals opposite to the coil of the stator, and a plurality of grooves formed in a bottom surface of the lower frame at fixed intervals along an inside circumference of the bottom surface, wherein the grooves are formed in a radial direction of the lower frame, wherein the grooves are formed by pressing the lower frame, and a drain hole provided in a bottom of at least one of the grooves. 
 
     
     
       14. A motor for a washing machine, comprising: a drive shaft;   a stator;   a rotor comprising a frame formed entirely of steel and configured to cover at least a portion of the stator, the rotor having a plurality of magnets positioned adjacent to a sidewall of the rotor and a bottom surface adjacent the sidewall, wherein a center portion of the rotor protrudes toward the stator and comprises a plurality of coupling holes and at least one fastening hole; and   a support member configured to connect the rotor to the drive shaft, wherein the support member comprises a plurality of fastening holes and at least one coupling projection configured to be inserted into a corresponding coupling hole of the rotor.   
     
     
       15. A motor for a washing machine, comprising:
 a drive shaft;   a stator;   a rotor comprising a frame formed entirely of steel and configured to cover at least a portion of the stator, the rotor having a plurality of magnets positioned adjacent to a sidewall of the rotor and a bottom surface adjacent the sidewall, wherein a center portion of the rotor protrudes toward the stator and includes a central opening having a projecting lip; and   a support member configured to connect the rotor to the drive shaft and having an opening for receiving therein the drive shaft, wherein corresponding projections and recesses are formed on mating portions of the drive shaft and the opening of the support member, and wherein the projecting lip of the rotor is configured to bear against and support the support member.   
     
     
       16. The motor of claim 15, wherein the support member comprises at least one reinforcing rib. 
     
     
       17. The motor of claim 16, wherein the at least one reinforcing rib comprises at least one circular rib. 
     
     
       18. The motor of claim 15, wherein the projecting lip extends substantially perpendicular to the bottom surface of the rotor, and then curves inward. 
     
     
       19. A washing machine, comprising:
 an outer tub;   an inner tub rotatably mounted within the outer tub; and   a motor comprising:
 drive shaft connected to the inner tub; 
 a single stator comprising a coil; and 
 a rotor comprising a frame formed entirely of steel and configured to cover at least a portion of the stator and to be connected to the drive shaft, the rotor having a plurality of magnets positioned adjacent to a sidewall of the rotor, a bottom surface adjacent the sidewall, and a plurality of cooling fins configured to project from the bottom surface of the rotor, wherein the sidewall comprises an extending lip at an end of the sidewall opposite the bottom surface of the rotor, and wherein the lip comprises a first portion that extends substantially perpendicular to the sidewall of the rotor, and a second portion that extends substantially perpendicular to the first portion.