Patent Document

BACKGROUND OF THE INVENTION 
   The present invention relates to a casing for an electric motor, and more particularly to an improved casing that reduces or eliminates the potential for water intrusion into the motor. 
   Many electric motors are subjected to conditions where water is present, either through splashing, raining or even being submerged. An example is an all-terrain vehicle (“ATV”) that may be used to cross creeks or streams. In many cases, electric motors of the ATV will be under water. The potential for water intrusion is particularly high when a motor and housing with an elevated temperature is submerged in cold water. If water enters a motor casing, it can have devastating effects on the ability of the motor to operate properly. Thus, there is a need for an improved electric motor and housing to minimize the risk for water intrusion. 
   SUMMARY OF THE INVENTION 
   The present invention is directed to an improved electric motor and housing that reduces the potential for water intrusion. A water-resistant electric motor includes a housing for receiving an electric motor armature therein and an end cap for closing an open end of the housing. The housing includes a drive shaft aperture within a cylindrical recess that receives a journal bearing and a ring seal. The end cap includes a wire access hole for receiving power supply wires. Surrounding the wire access hole is a ridge with cut-outs. A wire cover plate is seated on top of the ridge and includes cut-outs that correspond to the cut-outs in the ridge so that the power supply wires are accommodated therein when the cover plate is secured to the ridge. The wire access hole includes a grommet to seal the hole. 
   These and other embodiments of the present invention will also become readily apparent to those skilled in the art from the following detailed description of the embodiments having reference to the attached figures, the invention not being limited to any particular embodiment(s) disclosed. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded view of an electrical motor incorporating the features of one embodiment of the present invention; 
       FIG. 2 . is a top perspective view of the end cap of the casing according to an embodiment of the present invention; 
       FIG. 3  is a perspective view of the underside of the end cap of the casing according to an embodiment of the present invention; 
       FIG. 4  is a top plan view of the top of the end cap of the casing; 
       FIG. 5  is a perspective view of the side of the end cap showing an exploded view of the wire cover plate assembly; 
       FIGS. 6A  and B are the underside and the top of the wire cover plate; 
       FIG. 7  is a plan view of the underside of the end cap; 
       FIG. 8  is a perspective view of the interior of the housing; and 
       FIG. 9  is a perspective view of the exterior of the housing. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   With reference to  FIGS. 1 through 9  of the drawings, the motor  50  comprises a generally cylindrical housing  1  with an open end for receiving the motor components therein, and an end cap  13  dimensioned to fit the open end housing  1 . The housing  1  opposing end is closed and includes an aperture  4  through which a drive shaft  15  extends. The end cap  13  is configured to have a wire access hole  21  to receive the wires  40  that supply current to the motor  50 . On the outer side of the end cap  13 , surrounding the wire access hole  21  is a ridge  55  with one or more recesses  56   a  in which the wires  40  rest. A wire cover plate  18  is dimensioned to fit snugly upon the ridge  55  and retains the wires  40  in place. Wire cover plate  18  may also be configured with one or more recesses  56   b  corresponding to the one or more recesses  56   a  of the ridge  55  for further securing of the wires  40 . 
   In one embodiment, the wire cover plate  18  is generally unshaped, having an open end to receive the wires  40 . In this embodiment the wires  40  (shown in dashed lines in  FIG. 4 ) rest against the outer surface of the end cap  13  seated within recesses  56   a, b  and are secured by the wire cover plate  18  preferably with a fastener  57 . The wires  40  pass through the hole in the end cap  13  and to the motor  50  to supply power. 
   In another embodiment a grommet  60  ( FIGS. 2 &amp; 3 ) is seated within the wire access hole  21  in the end cap  13 . The grommet  60  includes holes through which the wires  40  pass, which are preferably sized to tightly accommodate the gauge of the wires  40 . Grommet  60  may be of any resilient, pliable, compressible material including without limitation rubber, silicon, or a polymeric substance, and may be dimensioned to be slightly greater in circumference than wire access hole  21 , such that the grommet  60  must be slightly compressed circumferentially to fit within the wire access hole  21  whereupon its resiliency causes it to expand to slightly beyond the circumference of the hole  21 . In height, and the grommet  60  should preferably slightly extend beyond the upper limits of the ridge  55  surrounding wire access hole  21  without compression, when seated within the hole  21 . Thus, in this embodiment, when the wire cover plate  18  is seated on the ridge  55  and secured in place to the end cap  13  with fastener  57 , the grommet  60  is compressed forming a seal within wire access hole  21 . 
   In a further embodiment, the end cap  13  inner surface is configured to have a ridge  71  surrounding the wire access hole  21  that forms a sealant reservoir  70  in which sealant  73  may be deposited. In this configuration, the sealant reservoir  70  provides a place to hold a sealant  73  to close off any remaining voids that may not have been adequately addressed by the wire cover plate mount  55  and grommet  60 . 
   The end cap  13  and the housing  1  may also include corresponding annularly disposed flanges  75 ,  85 , extending outwardly with respect to the interior of the end cap and housing. Each such annular includes a plurality of extensions  76   a - d , corresponding to the extensions  86   a - d  on the opposing flange  75 ,  85 . The extensions  76 ,  86  include one or more apertures that corresponding to one or more apertures within the extensions on the opposing flange for receiving fasteners for securing the end cap  13  to the housing  1 . An O-ring  43  of suitably resilient, compressible, pliable material may be seated between the respective flanges  75 ,  85 . Additionally, the end cap  13  may include an annular rim  37  providing a male extension extending longitudinally toward, and sized to be snugly received within the opening of the housing  1 . The O-ring  43  is then seated along the outer periphery of the annular rim  37 . It will be appreciated by those skilled in the arts that in the alternative the housing  1  could be configured with the annular rim to fit within the end cap  13 . 
   It will also be appreciated that the housing  1  and end cap  13  could be secured in any of the known conventional means, including having the securing means (i.e., a bolt) screwed into threaded holes disposed on the interior of the housing opening. One drawback of this configuration is that it provides an additional point of potential water intrusion. 
   Drive shaft  15  extends through an aperture  4  in the housing  1  end, the drive shaft aperture  4  is positioned co-centric with the longitudinal axis of the housing and thus the motor and is surrounded by a generally cylindrical recess  62  that accommodates a journal bearing  6 , which may be press fit into the recess and sized to tightly fit the drive shaft  15 , and the recess  62 . One embodiment also uses a ring seal  5  about the drive shaft  15  and located intermediate the journal bearing  6  the housing  1  within the recess  62 . Ring seal  5  may have an outside diameter approximately coincident with the outside diameter of the journal bearing  6 , to reduce or eliminate any water from entering the housing  1  even if water passes through the fit of the housing bearing  6 . Again, ring seal is made from a suitable resilient, compressible material, for example, rubber, silicon or a pliable polymeric. 
   The housing  1  may be made in any of the known conventional means, including as a weldment of two or more pieces of rolled sheet metal attached together by a seam. Alternatively, the housing  1  is a one-piece seamless member, formed by casting or by stamping, thereby eliminating potential water intrusion along the seam. In such a case, the only three potential water intrusion points are thus around the drive shaft aperture, between the connection of the housing  1  to the end cap  13 , and the wire access hole  21 . This invention, configured as described above, therefore, reduces, or eliminates the risk of water entry in these areas. 
   Additional means to eliminate or reduce the possibility of water intrusion to sensitive parts of the motor are used along the drive shaft  15  inside the housing. The drive shaft  15  may be formed with one or more grooves  92  disposed circumferentially around the shaft  15  and configured to receive a shaft O-ring  93  and disposed along the shaft to abut the interior housing surface at the drive shaft opening  4  and sized to extend slightly beyond the inner diameter of the drive shaft aperture  4  through which the drive shaft  15  passes. 
   The housing  1  may be made of any conventional metal. Also, the housing  1  is configured to have a bush collar  2  corresponding to the inside diameter of the housing  1  and resting within the housing  1 . The bush collar  2  acts as a flux insulator between the metal housing  1  and the magnets  3 , maintaining an elevated degree of magnetic flux around the magnets. Alternatively, the housing  1  could have an integral flux insulating layer. The magnets  3  are located around the interior diameter of the bush collar  2  and are preferably secured in place by springs or clips, the springs or clips exerting a force urging the magnets  3  apart and against the inner wall of the collar  2  thus holding them apart by tension. Alternatively, the magnets  3  can be secured by means incorporated into the housing  1  (or bush collar  2  if used) or end cap  13 , for example having perpendicular posts (not depicted) projecting from the internal face spaced around the periphery, and having grooves to receive the edges of the magnets. Alternatively, the magnets  3  can be affixed to the housing  1  (or bush collar  2 ) by an adhesive or by integral grooves or clips. Additional magnet supports (not depicted) allocated on the side of the housing  1  closer to the motor shaft  15  can be used to provide further means to keep the magnets secured. 
   This invention may be provided in other specific forms and embodiments without departing from the essential characteristics as described herein. The embodiments described above are to be considered in all aspects as illustrative only and not restrictive in any manner. The following claims rather than the foregoing description indicate the scope of the invention. 
   As described above and shown in the associated drawings, the present invention comprises a water-resistant electric motor. While particular embodiments of the invention have been described, it will be understood, however, that the invention is not limited thereto, since modifications may be made by those skilled in the art, particularly in light of the foregoing teachings. It is, therefore, contemplated by the appended claims to cover any such modifications that incorporate those features or those improvements that embody the spirit and scope of the present invention.

Technology Category: h