Abstract:
Disclosed is a rotor housing for a motor. The rotor housing has a shaft bushing in the center thereof and includes a plurality of operating holes disposed at a defined position between an outer circumference of the rotor housing and the shaft bushing. The defined position corresponds to the position of a plurality of holes formed in a stator to be coupled to the rotor housing.

Description:
CROSS REFERENCE TO PRIOR APPLICATIONS 
       [0001]    This application is a Divisional Application of U.S. patent application Ser. No. 13/639,670 filed on Oct. 24, 2012 under 35 U.S.C. §121, which is a National Stage Patent Application of PCT International Patent Application No. PCT/KR2011/001597 filed on Mar. 8, 2011 under 35 U.S.C. §371, which claims priority to Korean Patent Application No. 10-2010-0041886 filed on May 4, 2010, which are all hereby incorporated by reference in their entirety. 
     
    
     BACKGROUND 
       [0002]    The present invention relates to a motor. More particularly, the present invention relates to a rotor housing structure and a method for assembling a motor set using the rotor housing structure that makes it easier to assemble a rotor and a stator of a motor set for washing machine on a motor set assembly. 
         [0003]    Generally, motors for driving a tub of a drum type washing machine are outer rotor type DD (Direct Driving) motors. The washing machine with a DD motor is assembled in an orderly manner that a stator is coupled to a motor set assembly of a washer main body, and then a rotor to the exterior of the stator.  FIG. 1  illustrates the assembly procedure of a conventional motor set. 
         [0004]    Referring to  FIG. 1 , a motor set assembly  100  is shown in step (a). In the center of the motor set assembly  100  is formed a shaft  101  for rotating the rotor, with a plurality of stator assembly holes  105  formed around the shaft  101  for fixing a stator  110  to the motor set assembly  100 . In step (b), a plurality of coupling bushings  111  are formed on the inner side of a stator  110 , and each of them has a hole  112 . The holes  112  are arranged in alignment with the stator assembly holes  105  of the motor set assembly  100  so that they are coupled to the stator assembly holes  105  through a plurality of rivets  115 , in step (c). In this way the stator  110  is coupled to the motor set assembly  100 . In step (d), a rotor  120  is applied to embrace the stator  110 . In the center of the rotor  120  is formed a resin-molded shaft bushing  125 , the center of which has a shaft coupling portion  121 . In step (e), a rotor fixing bolt  126  is fitted in the shaft coupling portion  121  to complete the assembly of the motor set. 
         [0005]    The assembly method of the conventional motor set involves applying the stator  110  to the motor set assembly  100  (in steps (b) and (c)) and then the rotor  120  to the motor set assembly  100  (in step (d)). This causes a strong friction between the rotor  120  and the stator  110  as the rotor  120  is applied to embrace the stator  110 , because a plurality of magnets (not shown) coupled to the inner side of the rotor  120  have a strong magnetic attraction towards the outer circumference (i.e., teeth) of the stator  110 . The friction leaves cracks on the magnets and ends up a need of replacing the whole rotor  120 , resulting in a deterioration of productivity. Moreover, the worker who manually applies the rotor to the stator can be seriously injured with his/her hands accidently stuck between the rotor and stator. 
         [0006]    To overcome the above-mentioned problems, the present invention proposes a novel rotor housing structure and a method for assembling a motor set, to improve the operation process. 
       SUMMARY 
       [0007]    Accordingly, the present invention has been made in view of the above-mentioned problems occurring in the prior art, and it is an object of the present invention to provide a novel rotor housing structure that makes it possible to couple both a rotor and a stator to a motor set assembly at the same time. 
         [0008]    It is another object of the present invention to provide a method for assembling a motor set that includes a step of applying both a rotor and a stator to a motor set assembly at the same time, thereby preventing damages on the magnets formed on an inner side of the rotor. 
         [0009]    It is further another object of the present invention to provide a method for assembling a motor set that enhances productivity. 
         [0010]    It is still further another object of the present invention to provide a method for assembling a motor set that prevents potential accidents of workers. 
         [0011]    To achieve the above object, according to the present invention, there is provided a method for assembling a motor set that includes: coupling a rotor housing having a plurality of operating holes to a stator having shaft bushings with holes formed therein through the operating holes, thereby making the holes to be seen through the operating holes; coupling the holes of the stator associated with the rotor housing to stator assembly holes of a motor set assembly, the holes of the stator being aligned with the stator assembly holes of the motor set assembly; and inserting rivets into the holes through the operating holes and coupling the rivets to the stator assembly holes. 
         [0012]    The method for assembling a motor set according to the present invention further includes: coupling a shaft coupling portion disposed in center of the rotor housing to a shaft of the motor set assembly. 
         [0013]    In another aspect of the present invention, there is provided a rotor housing, which has a shaft bushing in the center thereof, the rotor housing including a plurality of operating holes disposed at a defined position between an outer circumference of the rotor housing and the shaft bushing. 
         [0014]    In the rotor housing of the present invention, the defined position corresponds to the position of a plurality of holes formed in a stator to be coupled to the rotor housing. 
         [0015]    The present invention introduces a step of applying both a rotor and a stator to a motor set assembly at the same time, to prevent damages on the magnets disposed on an inner side of the rotor, reducing defectiveness of the product and increasing productivity, and to prevent potential accidents of workers. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a schematic of the assembly procedure according to a conventional method for assembling a motor set; 
           [0017]      FIG. 2  is a perspective showing a rotor housing according to the present invention; and 
           [0018]      FIG. 3  is a schematic showing a method for assembling a motor set according to the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    Hereinafter, an explanation on the preferred embodiments of the present invention will be given in detail with reference to the attached drawings. 
         [0020]      FIG. 2  is a perspective showing a rotor housing  10  according to the present invention. 
         [0021]    In the center of the rotor housing  10  of the present invention is formed a shaft bushing  11 , as shown in  FIG. 2 . The shaft bushing  11  preferably is, but not limited to, a resin-molded portion to be coupled to a shaft of the motor. Otherwise, the shaft bushing  11  may be formed from a separate member other than a resin molding material, or formed in integration with the rotor housing  10  instead of using a separate member, to have a shape suitable for the shaft to be coupled to the center of the rotor housing  10 . 
         [0022]    The center of the shaft bushing  11  has a shaft coupling portion  12  to be coupled to a shaft  101  of a motor set assembly  100 . And a plurality of operating holes  15  are formed between the shaft bushing  11  and the outer circumference of the rotor housing  10 . The operating holes  15  are arranged in alignment with coupling bushings  111  of a stator  110 . Holes  112  of the coupling bushings  111  on the inner side of the stator  110  can be seen through the operating holes  15  so that rivets  115  are fitted in the holes  112  through the operating holes  15 . In other words, the operating holes  15  provide operation spaces for the stator  110  to be coupled to the motor set assembly  100  through the rivets  115 . The number of the operating holes is, but not limited to, six in  FIG. 2  and may depend on the number of the coupling bushings and the holes formed in the stator. 
         [0023]    With a plurality of operating holes  15 , the rotor housing  10  facilitates an assembly of the rivets  115  through the operating holes  15 , thus improving the motor set assembly process. The improved method for assembling a motor set is described below with reference to  FIG. 3 . 
         [0024]      FIG. 3  shows the respective steps of the method for assembling a motor set according to the present invention. 
         [0025]    Referring to  FIG. 3 , the rotor housing  10  is coupled to the stator  110 , in step (a), where the operating holes  15  of the rotor housing  10  are aligned with the holes  112  of the coupling bushings  111 . In other words, the rotor housing  10  is coupled to the stator  110  to make the holes  112  to be seen through the operating holes  15 . This step (a) is the obvious feature that makes the present invention different from the conventional assembly method. As illustrated in  FIG. 1 , the conventional method for assembling a motor set involves applying the stator  110  to the motor set assembly  100  and then the rotor  120  to the stator  110  coupled to the motor set assembly  100 , increasing chances of causing damages on the magnets of the rotor  120  or potential accidents of the worker whose hands accidently get stuck between the rotor and the stator. The present invention, on the other hand, allows the rotor housing  10  to be applied to the stator  110  not coupled to the motor set assembly  100 , providing a space conveniently large enough for the rotor housing  10 . This may prevent such problems concerning damages on the magnets or potential accidents of the worker. 
         [0026]    In step (b), both the rotor housing  10  and stator  110  coupled to each other are applied to the motor set assembly  100 . Here, stator assembly holes  105  of the motor set assembly  100  are aligned with the holes  112  of the shaft bushings  110 . 
         [0027]    In step (c), the rivets  115  are inserted in the holes  112  through the operating holes  15  of the rotor housing  10 . With the rivets  115  in the holes  112 , the stator  110  can be coupled tightly to the motor set assembly  100 . Rotor fixing bolt  16  is then applied to complete the assembly of the motor set, in step (d). If necessary, step (d) may precede step (c). 
         [0028]    While the present invention has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention.