Patent Publication Number: US-2009230799-A1

Title: Fixing strcture of motor spindle

Description:
FIELD OF THE INVENTION 
     The present invention relates to a fixing structure of motor spindle, and more particularly to a practical structure capable of preventing a snap ring from disengaging and avoiding to generate noise out of abrasion. 
     BACKGROUND OF THE INVENTION 
     As shown in  FIG. 1 , a motor structure applied in a cooling fan includes a stator  10  and a rotor  20 , in which the stator  10  is fixedly disposed on a shaft tube seat  30 , a shaft tube  31  is centrally fixed in the shaft tube seat  30 , a bearing  32  is disposed inside the shaft tube  31 , the rotor  20  is integrally combined and fixed with a hub  21 , the hub  21  caps and envelops the stator  10  so that an air gap is exactly maintained between the rotor  20  and the stator  10  and correspondingly located over an inner side of the stator  10 . 
     Moreover, a spindle  22  is centrally disposed in the hub  21 ; after being inserted in an oil seal  33  and a gasket  34 , the spindle  33  can then pass through the bore of the bearing  32 ; an outer end of the spindle  22  stretching beyond the bearing  32  sequentially penetrate through an oil seal  35 , a washer  36  and a gasket  37 , and a snap ring  41  is fixedly retained in a snap slot on the end portion of the spindle  22 ; lastly, an end cap  38  is used to fully seal the bottom portion of the shaft tube  31 . 
     Together with the illustration of  FIG. 2 , when the snap ring  41  of the conventional structure is fixedly retained in the snap slot  23  on the end portion of the spindle  22 , the outer diameter of the snap slot is greater than the inner diameter of the snap ring  41  and the outer diameter of the spindle  22  is greater than the outer diameter of the snap slot  23  so that a seamless and tight fitting is present between the snap ring  41  and the snap slot  23  and easily results in deformation of the entire snap ring  41  and functional loss of the snap ring  41 . As a result, when the spindle  22  is rotating, the snap ring surely rotates with the spindle  22 , making that the snap ring  41  collides with the oil seal  35 , the washer  36 , the gasket  37  and so on to generate noise. Meanwhile, the snap ring  41  is positioned in an unstably rotating condition for long while and is easier to disengage from the snap slot  23 . 
     SUMMARY OF THE INVENTION 
     The main object of the present invention is to provide a fixing structure of motor spindle, which maintains a gap between the hole of a snap ring and an outer diameter of the snap slot to prevent the snap ring from rotating with the spindle in generation of noise out of abrasion and from disengaging. 
     The fixing structure of motor spindle of the present invention includes a spindle whose one end has a snap slot with a smaller outer diameter; a snap ring retained in the snap slot on the spindle whose inner hole is slightly larger than the maximum outer diameter of the snap slot on the spindle, so that a gap being the difference of radii thereof is maintained in size of less than or equivalent to 0.37 mm between the hole of the snap ring and the snap slot of the spindle. 
     Therefore, when an end of the spindle is pushed in the snap ring, it is easily retained by the snap ring without giving rise to deformation of the snap ring. At the same time, the rotor is stably positioned to rotate, getting rid off the requirement of oil ring, washer and gasket. Besides, when the spindle is rotating, the snap ring of the present invention won&#39;t rotate with the spindle as a result of the holding effect of a bearing and a bottom cap, not only stably holding and fixing the spindle to prevent it from disengaging but also generating no issue of noise out of abrasion for sake of attainting the demand for cost reduction and reliable quality. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view showing a conventional structure; 
         FIG. 2  is a partially enlarged schematic view showing a conventional structure; 
         FIG. 3  is a cross-sectional view of the present invention; and 
         FIG. 4  is a partially enlarged view of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention relates to a fixing structure of motor spindle, as shown in  FIG. 3 , which includes a stator  10  fixedly disposed on a shaft tube seat  30 , in which a shaft tube  31  is centrally fixed in the shaft tube seat  30  and a bearing  32  is disposed inside the shaft tube  31 , a rotor  20  integrally combined and fixed with a hub  21 , in which the hub  21  can cap and envelop the stator  10  and an air gap is maintained between the rotor  20  and the stator  10 . 
     Moreover, the hub  21  has a spindle  22  centrally; an outer end of the spindle  22  has a snap slot  23  with a reduced outer diameter; after the spindle passes through the bore of the bearing  22 , a snap ring  42  is used to hold and position the snap slot  23  of its end portion; lastly, the bottom portion of the shaft tube  31  is sealed with a bottom cap  39 . 
     Further in combination with the illustration of  FIG. 4 , the inner hole of the snap ring  42  shall be slightly greater than the maximum outer diameter of the snap slot  23  on the spindle  22  in the present invention. After the snap ring  42  is retained in the snap slot  23 , a gap of the radius difference for the inner hole of the snap ring  42  and the snap slot in size of less than or equivalent to 0.37 mm is reserved. 
     In view of a gap  43  maintained between the inner hole of the snap ring  42  and the outer diameter of the snap slot  23  in the present invention and the periphery of the snap ring  42  held and fixed by the bearing  32  and the bottom cap  39 , the rotor  20  held and positioned by the snap ring  42  won&#39;t require additional oil seal, washer and gasket. When the spindle  22  is rotating, the snap ring  42  of the present invention won&#39;t rotate with the spindle  22 , won&#39;t generate noise due to abrasion with the spindle  22  either and is free of the deformation concern of the snap ring  42 . 
     In sum, not only can the snap ring  42  of the present invention stably hold and position the spindle  22  to prevent from disengaging, but also it is free of the issue of noise out of abrasion and the mounting of oil seal, washer and gasket. From the above-mentioned characteristics those features not only have a novelty among similar products and a progressiveness but also have an industry utility. 
     While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the circular disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.