Patent Publication Number: US-2006012261-A1

Title: Stator for electrical motor

Description:
TECHNICAL FIELD  
      The present invention relates generally to electrical motors, and more particularly to a stator of such a motor.  
     BACKGROUND  
      Electrical motors have been widely used to transfer electrical energy to mechanical energy in a form of rotational motion. For example, in a heat-dissipating fan, an electrical motor is used to drive fan blades to rotate therewith, thereby generating airflow toward heat-generating components.  
      The electrical motor usually includes a stator and a rotor rotatable with respect to the stator. Referring to  FIG. 4 , such a stator  1 ′ typically includes a stator core  10 ′ having a plurality of winding slots for receiving stator coils (not shown) therein. To avoid the coils to electrically contact the stator core  10 ′, upper and lower insulating frames  12 ′,  14 ′ are used to cover the stator core  1 ′ and electrically insulate the stator coils from the stator core  10 ′.  
      The upper and lower insulating frames  12 ′,  14 ′ respectively form a plurality of flanges  102 ′,  104 ′ extending from edges thereof. These flanges  12 ′,  14 ′ extends into the winding slots to cover the stator core  10 ′. On the other hand, these flanges  102 ′,  104 ′ engage with the stator core  10 ′ at the winding slots, thereby serving as positioning the upper and lower insulating frames  12 ′,  14 ′ to the stator core  10 ′.  
      Since the upper and lower insulating frames  12 ′,  14 ′ are generally made of plastic material and there lacks a reliable mechanism to firmly interconnect the frames  12 ′,  14 ′ with the stator core  10 ′, the insulating frames  12 ′,  14 ′ may deform or separate from the stator core  10 ′ during operation of the motor, and thus fail to completely insulate the stator coils from the stator core  10 ′, which in turn may result in an undesired electrical connection between the stator core  10 ′ and the stator coils. This will be more likely to occur especially when the electrical motor is used in situations where a lot of shocks or vibrations exist. Therefore, a heretofore unaddressed need exists in the industry to address the aforementioned deficiencies and inadequacies.  
     SUMMARY OF THE INVENTION  
      The present invention provides a stator for an electrical motor. The stator comprises a stator core and an insulating member attached to the stator core. The stator core comprises a first engaging structure. The insulating member comprises portions to cover the stator core, thereby insulating the stator core from stator coils, and a first engaging structure other than said portions. The first engaging structure engages with the second engaging structure to interconnect the stator core and the insulating member. According to a preferred embodiment, the first engaging structure comprises a plurality of mounting holes, and the second engaging structure comprises a plurality of mounting protrusions engaged in the mounting holes respectively.  
      Other systems, methods, features and advantages of the present invention will be drawn from the following detailed description of the preferred embodiments of the present invention with attached drawings, in which: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is an isometric, exploded view of a stator according to a preferred embodiment of the present invention;  
       FIG. 2  is similar to  FIG. 1 , but viewed from another aspect;  
       FIG. 3  is an assembled view of the stator of  FIG. 1 ; and  
       FIG. 4  is an isometric, exploded view of a conventional stator. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT  
       FIGS. 1 and 2  show a stator  1  of a motor in accordance with a preferred embodiment of the present invention. The stator  1  comprises a stator core  10 , upper and lower insulating frames  12 ,  14  for being attached to top and bottom sides of the stator core  10  respectively, and a PCB  18  (Printed Circuit Board) for being attached to the lower insulating frame  14 . For the sake of simplicity, the stator coils of the stator  1  are omitted.  
      The stator core  10  may comprise a plurality of laminated silicon steel sheets. The stator core  10  comprises a center portion  102 , and four generally T-shaped pole members  104  extending radially and outwardly from the center portion  102 . Each pole member  104  has an arc-shaped wing  106  formed at its free end. Every two adjacent pole members  104  and a part of the center portion  102  cooperatively form a winding slot  105  therebetween for receiving a corresponding stator coil therein. Alternatively, the stator core  10  may form more than or less than four pole members  104  according to practical needs. A plurality of mounting holes  108  is defined through the stator core  10  around the center portion  102  thereof.  
      The upper insulating frame  12  comprises a center portion  121  corresponding to the center portion  102  of the stator core  10 , and four generally T-shaped extensions  122  formed around the center portion  121  corresponding to the pole members  104  of the stator core  10  respectively. The center portion  121  and the extensions  122  form a plurality of flanges  123  at edges thereof. These flanges  123  extend into the winding slots  105  of the stator core  10 , respectively, when the upper insulating frame  12  is attached to the top side of the stator core  10 .  
      As can be better seen in  FIG. 2 , a plurality of mounting protrusions  124  is formed on a bottom surface of the upper insulating frame  12 , for extending into the mounting holes  108  of the stator core  10  respectively when the upper insulating frame  12  is attached to the topside of the stator core  10 .  
      The lower insulating frame  14  generally has the same configuration as the upper insulating frame  12 . The lower insulating frame  14  also has a center portion  141  and four generally T-shaped extensions  142  formed around the center portion  141 . Flanges  143  extend from edges of the center portion  141  and the T-shaped extensions  142 . The lower insulating frame  14  forms a plurality of mounting protrusions  144 , for extending into the mounting holes  108  of the stator core  10  when the lower insulating frame  14  is attached to the bottom side of the stator core  10 .  
      Each extension  142  forms downwardly toward the PCB  18  a leg  147 . Three positioning pins  16  extend downwardly from the legs  147  toward the PCB  18 , and the PCB  18  defines three positioning holes  180  for receiving the positioning pins  16  therein, thereby attaching the PCB  18  to the lower insulating frame  14 .  
      Referring to  FIG. 3 , in assembly of the stator  1 , the upper insulating frame  12  is placed upon the top side of the stator core  10 , with the mounting protrusions  124  aligned with the mounting holes  108  of the stator core  10  respectively. The upper insulating frame  12  is then pressed against the stator core  10 , so that the mounting protrusions  124  are engagingly received in the mounting holes  108  respectively. The upper insulating frame  12  is thus assembled to the top side of the stator core  10 . Simultaneously, the flanges  123  extend into the winding slots  105  to surround upper portions of the winding slots  105  and cover upper portions of side surfaces of the stator core  10  facing the winding slots  105 .  
      In substantial the same manner, the lower insulating frame  14  is assembled to the bottom side of the stator core  10 , with the mounting protrusions  144  engagingly received in the mounting holes  108  and the flanges  143  covering lower portions of the side surfaces of the stator core  10  facing the winding slots  105 .  
      Finally, the positioning pins  16  of the lower insulating frame  14  are engaged into the positioning holes  180  of the PCB  18  to attach the PCB  18  to the lower insulating frame  14 .  
      In the stator  1  of the preferred embodiment of the present invention, the upper and lower insulating frames  12 ,  14  respectively cover top and bottom portions of the stator core  10 . The upper and lower insulating frames  12 ,  14  form the mounting protrusions  124 ,  144  engaging into the mounting holes  108  of the stator core  10 . This configuration enhances interconnection strength and reliability of the upper and lower insulating frames  12 ,  14  with the stator core  10 . Possibility of deformation of the upper and lower insulating frames  12 ,  14  is reduced and an overall integrity of the stator  1  is thus improved.  
      In the stator  1  according to the preferred embodiment of the present invention, the mounting holes  108  are defined through the stator core  10 , and the mounting protrusions  124 ,  144  extend into the mounting holes  108  respectively from opposite top and bottom ends thereof. Alternatively, a plurality of blind holes may be defined in the stator core  10  at opposite top and bottom sides thereof, for respectively receiving the mounting protrusions  124 ,  144  of the upper and lower insulating frames  12 ,  14 .  
      In addition, in the preferred embodiment of the present invention, the mounting holes  108  are formed in the stator core  10 , and the mounting protrusions  122 ,  144  are formed on the upper and lower insulating frames  12 ,  14 . Alternatively, the mounting holes may be defined in the upper and lower insulating frames, while the mounting protrusions may be formed on the stator core.  
      Further, in the preferred embodiment of the present invention, the mounting protrusions  124 ,  144  are shaped in a form of posts. The mounting protrusions, however, may be embodied in other forms such as, for example, in a form of bumps, clips.  
      It is understood that the invention may be embodied in other forms without departing from the spirit thereof. The above-described examples and embodiments are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given above.