Abstract:
A method of manufacturing a rotor includes steps of providing a rotor casing and a bearing, wherein the rotor casing has an axial hole; disposing the bearing in the axial hole; and using a laser to weld an inner edge of the axial hole and an outer edge of the bearing, so as to fix the bearing with the axial hole.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to a method of manufacturing a rotor and, more particularly, to a method using a laser to weld a bearing with a rotor casing. 
         [0003]    2. Description of the Prior Art 
         [0004]    A motor is a driving device widely used in daily life. The motor can convert electrical energy into mechanical energy and then generate kinetic energy through mechanical energy, so as to drive other devices. The motor essentially consists of a rotor, a stator, a bearing and so on. In the prior art, the bearing is disposed in an axial tube of the stator and an axle of the rotor is inserted into the bearing. When the motor is activated, the stator is immovable and the rotor rotates on the axle with respect to the bearing. In general, the bearing is fixed in the axial tube of the stator in a tight-fitting manner. When the rotor is rotating, the bearing may come off the axial tube of the stator due to vibration resulted from high speed rotation, such that the motor may fail or other components may be damaged. 
       SUMMARY OF THE INVENTION 
       [0005]    The invention provides a method using a laser to weld a bearing with a rotor casing, so as to solve the aforesaid problems. 
         [0006]    According to an embodiment of the invention, a method of manufacturing a rotor comprises steps of providing a rotor casing and a bearing, wherein the rotor casing has an axial hole; disposing the bearing in the axial hole; and using a laser to weld an inner edge of the axial hole and an outer edge of the bearing, so as to fix the bearing with the axial hole. 
         [0007]    As mentioned in the above, the invention uses the laser to weld the bearing with the rotor casing and the laser welding process can form good connection strength between the bearing and the axial hole of the rotor casing. Accordingly, when the rotor is rotating, the bearing will not come off the axial hole of the rotor casing due to vibration resulted from high speed rotation. Therefore, the useful life of a motor can be improved effectively. 
         [0008]    These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a perspective view illustrating a rotor according to an embodiment of the invention. 
           [0010]      FIG. 2  is a perspective view illustrating the rotor shown in  FIG. 1  from another viewing angle. 
           [0011]      FIG. 3  is a flowchart illustrating a method of manufacturing the rotor shown in  FIG. 1 . 
           [0012]      FIG. 4  is a schematic view illustrating the process associated with the method shown in  FIG. 3 . 
           [0013]      FIG. 5  is a perspective view illustrating a rotor according to another embodiment of the invention. 
           [0014]      FIG. 6  is a perspective view illustrating a rotor according to another embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Referring to  FIGS. 1 to 4 ,  FIG. 1  is a perspective view illustrating a rotor  1  according to an embodiment of the invention,  FIG. 2  is a perspective view illustrating the rotor  1  shown in  FIG. 1  from another viewing angle,  FIG. 3  is a flowchart illustrating a method of manufacturing the rotor  1  shown in  FIG. 1 , and  FIG. 4  is a schematic view illustrating the process associated with the method shown in  FIG. 3 . 
         [0016]    The rotor  1  of the invention is adapted to a motor, a fan or other driving devices. The rotor  1  can cooperate with a stator to convert electrical energy into mechanical energy and then generate kinetic energy through mechanical energy. To manufacture the rotor  1 , first of all, step S 10  is performed to provide a rotor casing  10  and a bearing  12 , wherein the rotor casing  10  has an axial hole  100 . Afterward, step S 12  is performed to dispose the bearing  12  in the axial hole  100 . Then, step S 14  is performed to use a laser  14  to weld an inner edge  102  of the axial hole  100  and an outer edge  120  of the bearing  12 , so as to fix the bearing  12  with the axial hole  100 . 
         [0017]    The laser welding process can form good connection strength between the bearing  12  and the axial hole  100  of the rotor casing  10 . Accordingly, when the rotor  1  is rotating, the bearing  12  will not come off the axial hole  100  of the rotor casing  10  due to vibration resulted from high speed rotation. Therefore, the useful life of a motor can be improved effectively. In this embodiment, the laser  14  may be a non-contact laser. If the bearing  12  and the axial hole  100  of the rotor casing  10  are welded by the non-contact laser, the connection strength between the bearing  12  and the axial hole  100  of the rotor casing  10  may be better. 
         [0018]    In this embodiment, the bearing  12  may be a ball bearing. Before using the laser  14  to weld the inner edge  102  of the axial hole  100  and the outer edge  120  of the bearing  12 , a gap may exist between the inner edge  102  of the axial hole  100  and the outer edge  120  of the bearing  12 . In other words, before using the laser  14  to weld the inner edge  102  of the axial hole  100  and the outer edge  120  of the bearing  12 , the inner edge  102  of the axial hole  100  and the outer edge  120  of the bearing  12  cannot be set in a tight-fitting manner, such that the laser  14  will not damage the balls of the bearing  12 . However, if the gap between the inner edge  102  of the axial hole  100  and the outer edge  120  of the bearing  12  is too big, the laser welding effect will not be good and the connection strength between the bearing  12  and the axial hole  100  of the rotor casing  10  will be insufficient. Accordingly, the gap between the inner edge  102  of the axial hole  100  and the outer edge  120  of the bearing  12  may be preferably smaller than or equal to 0.02 mm, so as to ensure that the connection strength between the bearing  12  and the axial hole  100  of the rotor casing  10  can be kept good. 
         [0019]    Referring to  FIG. 5 ,  FIG. 5  is a perspective view illustrating a rotor  3  according to another embodiment of the invention. The difference between the rotor  3  and the aforesaid rotor  1  is that after manufacturing the rotor  1 , the invention may further form a plurality of fan blades  30  on an outer edge  104  of the rotor casing  10  by an injection molding process, so as to manufacture the rotor  3  shown in  FIG. 5 . At this time, the rotor  3  can be used as a fan wheel. 
         [0020]    Referring to  FIG. 6 ,  FIG. 6  is a perspective view illustrating a rotor  5  according to another embodiment of the invention. The difference between the rotor  5  and the aforesaid rotor  1  is that the rotor  5  further comprises a plurality of fan blades  50 , wherein the fan blades  50  extend from an outer edge  104  of the rotor casing  10  and are formed with the rotor casing  10  integrally, as shown in  FIG. 6 . At this time, the rotor  5  can be used as a fan wheel. 
         [0021]    As mentioned in the above, the invention uses the laser to weld the bearing with the rotor casing and the laser welding process can form good connection strength between the bearing and the axial hole of the rotor casing. Accordingly, when the rotor is rotating, the bearing will not come off the axial hole of the rotor casing due to vibration resulted from high speed rotation. Therefore, the useful life of a motor can be improved effectively. 
         [0022]    Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.