Abstract:
A motor with an oil seal. The oil seal includes a first storage wall disposed in a position corresponding to a recess of a shaft. The oil seal receives lubricant and prevents leakage of the lubricant, enhancing self-lubrication of the motor. A bottom storage tank with a specific sloped surface is provided in the motor. During rotation of the shaft, the bottom storage tank increases usage of the lubricant, thereby enhancing self-lubrication of the motor.

Description:
BACKGROUND  
       [0001]     The invention relates to a motor and in particular to a motor providing self-lubrication function.  
         [0002]     Motors, which have a simplified structure and low cost, are widely used to serve as power sources. For example, a motor can be employed in a fan, a compressor, or other devices requiring mechanical operation.  
         [0003]     A conventional motor with self-lubricating function can have a long lifespan. As shown in  FIG. 1 , a motor  1 , such as a fan motor, comprises a base  10 , a rotor  12 , multiple blades  18 , and a driving device  16 . The base  10  comprises an axial hole  101  in which a bearing  13  is disposed. The rotor  12  is connected to a shaft  14 . The shaft  14  fits in the bearing  13 . The driving device  16  is located between the rotor  12  and the base  10  and comprises a coil  161  and a magnet  162 . The coil  161  is above the base  10  while the magnet  162  is on the rotor  12  and corresponds to the coil  161 . The coil  161  and magnet  162  are not limited to the aforementioned positions. Namely, the positions of the coil  161  and magnet  162  can be exchanged to provide the same operation. When the coil  161  is loaded with electric currents, a magnetic field induced by the coil  161  interacts with the magnet  162  to turn the rotor  12 . The rotor  12  rotates with respect to the base  10  by means of the shaft  14 . The blades  18  rotate with rotor  12 , providing functions of heat dissipation. Further, the base  10  can be connected to an outer frame  19  to improve the flow field generated by rotation of the blades  18 . The heat dissipation performance of the motor  1  can thus be enhanced. Moreover, to enable free rotation of the shaft  14  with respect to the bearing  13  and to prolong the lifespan of the shaft  14  and bearing  13 , lubricant is filled between the shaft  14  and the bearing  13 , reducing friction therebetween. Additionally, the base  10  comprises a storage tank  100  disposed near one end of the shaft  14 . Please refer  FIG. 1 . The storage tank  100  is often closed and receives the lubricant overflowing from the connection between the bearing  13  and the shaft  14 .  
         [0004]     Accordingly, when the shaft  14  rotates with respect to the bearing  13 , the amount of lubricant carried by the shaft  14  is quite limited. The lubricant is carried by using pumping effect provided by the bearing  13  in chief. The lubricant in the internal grooves of the bearing  13  is drawn to the interface of the shaft  14  and bearing  13 , providing lubrication therebetween. Specifically, a portion of the lubricant returns to the internal grooves of the bearing  13 . Another portion of the lubricant vaporizes due to a high temperature resulting from the friction between the shaft  14  and the bearing  13 . Yet another portion of the lubricant spreads out from the interface of the shaft  14  and bearing  13  and is received in the storage tank  100 . Furthermore, after the motor  1  operates for a long time, most of the lubricant is received in the storage tank  100 , this portion of lubricant received in the storage tank  100  cannot re-enter the bearing  13 . The lubrication effect between the shaft  14  and the bearing  13  is thus decreased. Moreover, when the shaft  14  rotates with respect to the bearing  13 , the lubricant may be drawn upward to the exterior of the shaft  14  and bearing  13 . At this point, the lubricant is lost and may be spread to the driving device  16 , causing damage to the driving device  16 .  
       SUMMARY  
       [0005]     The invention provides a motor having an oil seal. The oil seal receives and prevents leakage of lubricant, enhancing self-lubrication of the motor.  
         [0006]     The invention provides a motor having a bottom storage tank with a specific sloped surface. The bottom storage tank can increase usage of the lubricant, thereby enhancing self-lubrication of the motor.  
         [0007]     Accordingly, an exemplary embodiment of the invention provides a motor comprising a base, a bearing, an oil seal, a rotor, and a driving device. The bearing is disposed in the base. Preferably, the bearing is disposed in an axial hole of the base. The oil seal is disposed in the base. The rotor comprises a shaft sequentially penetrating the oil seal and bearing. Lubricant is filled between the shaft and the bearing, providing lubrication during rotation of the rotor. The oil seal comprises a first storage wall disposed in a position corresponding to a recess of the shaft. The driving device is disposed between the rotor and the base to drive the rotor with respect to the base.  
         [0008]     In some embodiments of the motor, the first storage wall is extended from the oil seal. A first storage tank is disposed between the inner surface of the first storage wall and the bearing to receive lubricant overflowing from the connection between the shaft and the bearing. The first storage wall is bent after extending from the oil seal to the shaft, and the end of the first storage wall faces the base.  
         [0009]     In some embodiments of the motor, the outer surface of the first storage wall is in the recess of the shaft. A first gap exists between the outer surface of the first storage wall and the recess of the shaft.  
         [0010]     In some embodiments of the motor, the rotor further comprises a second storage wall disposed on the connection between the rotor and the shaft. A second storage tank is disposed between the second storage wall and the shaft to receive lubricant overflowing from the first gap.  
         [0011]     In some embodiments of the motor, the oil seal further comprises a fixing portion, and the fixing portion fixes the oil seal to the base.  
         [0012]     In some embodiments of the motor, the oil seal further comprises an extending portion. A second gap exists between the extending portion and the rotor to dissipate surplus lubricant.  
         [0013]     In some embodiments of the motor, the motor can be a fan motor comprising a plurality of blades connected to the exterior of the rotor. The blades rotate when the motor operates.  
         [0014]     In some embodiments of the motor, the motor further comprises an outer frame connected to the base and covering the blades.  
         [0015]     In some embodiments of the motor, the driving device further comprises a coil and a magnet corresponding to the coil. The coil and magnet are respectively disposed on the base and rotor. The motor can operate when the coil is loaded with electric currents.  
         [0016]     In some embodiments of the motor, the motor further comprises a bottom storage tank disposed on one end of the shaft to receive the lubricant. The bottom storage tank comprises a sloped surface enclosing the shaft.  
         [0017]     In some embodiments of the motor, the sloped surface comprises a curvedly extended sloped surface or a radially extended sloded surface.  
         [0018]     In some embodiments of the motor, the bottom storage tank and base are integrally formed.  
         [0019]     In some embodiments of the motor, the bottom storage tank is connected to the end of the shaft to rotate with the shaft. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0020]     The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:  
         [0021]      FIG. 1  is a schematic cross section of a conventional fan motor;  
         [0022]      FIG. 2  is a schematic cross section of the fan motor of the invention;  
         [0023]      FIG. 3  is a schematic perspective view of the oil seal of the fan motor of the invention;  
         [0024]      FIG. 4  is a partial enlarged view of  FIG. 2 ;  
         [0025]      FIG. 5  is a schematic perspective view of a curvedly extended sloped surface of the bottom storage tank of the motor of the invention; and  
         [0026]      FIG. 6  is a schematic perspective view of a radially extended sloped surface of the bottom storage tank of the motor of the invention. 
     
    
     DETAILED DESCRIPTION  
       [0027]     Referring to  FIG. 2 , the motor may be a fan motor  2  comprising a base  20 , a rotor  22 , a plurality of blades  28 , and a driving device  26 . The driving device  26  comprises a coil  261  and a magnet  262  corresponding to the coil  261 . The coil  261  and magnet  262  are disposed on the base  20  and rotor  22 , respectively. The fan motor  2  further comprises an oil seal  25  disposed in the upper portion of an axial hole  201  of the base  20 . A shaft  24  sequentially penetrates the oil seal  25  and bearing  23 . The rotor  22  can rotate with respect to the base  20  by means of the shaft  24 . The blades  28  can rotate with the rotor  22 , thereby providing a heat dissipation function. Moreover, the base  20  is connected to an outer frame  29  to improve the flow field generated by rotation of the blades  28 . Performance of heat dissipation of the fan motor  2  is thus enhanced.  
         [0028]     Referring to  FIG. 3  and  FIG. 4 , the oil seal  25  is annular and comprises a first storage wall  251 , a fixing portion  250 , and an extending portion  254 . The oil seal  25  further comprises a through hole  255  through which the shaft  24  passes. The fixing portion  250  fixes the oil seal  25  to the upper portion of the axial hole  201  of the base  20 . As shown in  FIG. 4 , the first storage wall  251  of the oil seal  25  is bent after extending from the oil seal  25  to the shaft  24 , and the end of the first storage wall  251  faces the base  20 . A first storage tank  252  is disposed between the inner surface of the first storage wall  251  and the bearing  23  to receive the lubricant overflowing from the connection between the shaft  24  and the bearing  23 . Additionally, the first storage wall  251  is disposed in a position corresponding to a recess  240  of the shaft  240 . Namely, the outside surface of the first storage wall  251  is extended in the recess  240 . When the lubricant overflows from the connection between the shaft  24  and the bearing  23 , most of the lubricant is guided into the first storage tank  252  by the first storage wall  251 . The lubricant then re-enters the connection between the shaft  24  and the bearing  23 , as indicated by arrow A in  FIG. 4 . Accordingly, loss of the lubricant can be prevented and self-lubrication of the fan motor  2  is thus not adversely affected. Moreover, a first gap  31  exists between the outer surface of the first storage wall  251  of the oil seal  25  and the recess  240  of the shaft  24 . The lubricant which is not received by the first storage tank  252  overflows via the first gap  31 . The rotor  22  further comprises a second storage wall  241  disposed near the connection between the rotor  22  and the shaft  24 . A second storage tank  242  is disposed between the second storage wall  241  and the shaft  24  to receive the lubricant overflowing from the first gap  31 . When the amount of the lubricant in the first storage tank  252  or between the shaft  24  and the bearing  23  is insufficient, the lubricant received by the second storage tank  242  can be fed back to the connection between the shaft  24  and the bearing  23 , to again provide self-lubrication. Additionally, a second gap  32  exists between the extending portion  254  and the rotor  22 . Since the second gap  32  has a zigzag structure, unnecessary dissipation of the lubricant, as indicated by arrow B in  FIG. 4 , can be retarded.  
         [0029]     Because of the structures of the oil seal  25 , recess  240  of the shaft  24 , and rotor  22 , most of the lubricant can be retrieved. Namely, dissipation of the lubricant can be reduced and malfunctioning of the self-lubrication of the fan motor  2  can be prevented.  
         [0030]     As shown in  FIG. 2 , the base  20  of the fan motor  2  further comprises a bottom storage tank  200  disposed on one end of the shaft  24  to receive the lubricant. To enhance retrieval usage of the lubricant, the bottom storage tank  200  comprises a sloped surface. When the shaft  24  rotates, the lubricant can be drawn up by the sloped surface and enter the connection between the shaft  24  and the bearing  23 , providing lubrication to the fan motor  2 . As shown in  FIG. 5 , the sloped surface of the bottom storage tank  200  may be a curvedly extended sloped surface  205 . Namely, the curvedly extended sloped surface  205  is a sloped surface gradually ascending in a curved manner. When the shaft  24  rotates, the lubricant can be drawn by the curvedly extended sloped surface  205  and rotate around the shaft  24 . The lubricant can ascend along the curvedly extended sloped surface  205  to the connection between the shaft  24  and the bearing  23 . Moreover, as shown in  FIG. 6 , the sloped surface of the bottom storage tank  200  may be a radially extended sloped surface  206 . Namely, the radially extended sloped surface  206  is a sloped surface gradually and outward ascending from the shaft  24 . When the shaft  24  rotates, the lubricant can be drawn by the radially extended sloped surface  206  and rotate around the shaft  24 . A centrifugal force is thus generated in the lubricant. The lubricant can ascend along the radially extended sloped surface  206  to the connection between the shaft  24  and the bearing  23 , providing lubrication to the fan motor  2 . Additionally, the curvedly extended sloped surface  205  or radially extended sloped surface  206  can be integrally formed with the base  20 , thereby reducing manufacturing costs of the fan motor  2 .  
         [0031]     The base  20  has the aforementioned sloped surface. When the shaft  24  rotates, the lubricant is drawn up by viscosity thereof along the sloped surface. The lubricant then enters the connection between the shaft  24  and the bearing  23 . In another aspect, the sloped surface (curvedly extended sloped surface  205  or radially extended sloped surface  206 ) may be formed with the shaft  24 . Thus, the sloped surface can rotate with the shaft  24 . Namely, the shaft  24  and sloped surface (curvedly extended sloped surface  205  or radially extended sloped surface  206 ) rotate synchronously. The lubricant can also ascend to the connection between the shaft  24  and the bearing  23 , providing lubrication to the fan motor  2 .  
         [0032]     Accordingly, the lubricant in the bottom storage tank  200  can be fully utilized. Thus, usage of the lubricant is increased, self-lubrication of the fan motor  2  is enhanced, and the lifespan of the fan motor  2  is prolonged.  
         [0033]     Additionally, the aforementioned structure of this embodiment is not limited to a fan motor. Namely, the aforementioned structure can also be employed in other motors requiring self-lubrication.  
         [0034]     While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.