Abstract:
A component for an electric machine includes a spool having a main body portion provided with a first end portion that extends substantially uninterrupted to a second end portion through an intermediate portion. A plurality of mounting elements are provided on the first end portion. A star member is operatively connected to the spool. The star member includes a main body, a plurality of flap members that extend from the main body and collectively define a central opening, and a plurality of mounting members that extend into the central opening. The plurality of mounting members engage with corresponding ones of the plurality of mounting elements to detachably mount the star member to the first end portion of the spool.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a divisional application of U.S. patent application Ser. No. 12/177,237 filed Jul. 22, 2008, the contents of which are incorporated by reference herein in their entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Exemplary embodiments of the invention relate to the art of electric machines and, more particularly, to a spool assembly for an electric machine. 
         [0003]    Certain electric machines, such as claw-pole alternators, include a rotor formed from a plurality of steel segments, a steel core, magnet wire, and a spool assembly. The spool assembly includes a spool configured to insulate the magnet wire from the steel core, and flaps that are configured to insulate the magnet wire from the steel segments. Prior art spools were formed completely from plastic. The plastic spools were bulky which limited carrying capacity for the magnet wire. 
         [0004]    Newer spool assemblies employ a plastic spool, indicated generally at  2  in  FIG. 1 , and laminate flaps (not shown) formed in a star. The laminate flaps or stars allowed for a spool assembly that was much thinner than the prior art plastic spool assemblies. The thinner design increased carrying capacity for the magnet wire and heat transfer from the spool assembly. While the newer spool assemblies have several advantages over the older completely plastic designs, a disadvantage exists in that the laminate flaps are attached to spool  2  by sonic welding. Not only is sonic welding a difficult and expensive process, sonic welding also requires that spool  2  include thick plastic portions in the form of opposing thick flanges  4  and  5  that provide weld support surfaces, one of which is indicated at  8 . The thick plastic portions or thick flanges  4  and  5  defeat the purpose of the new design. That is, by adding thick flanges  4  and  5  to spool  2 , magnet wire carrying capacity is reduced. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0005]    In accordance with an exemplary embodiment of the invention, a component for an electric machine includes a spool having a main body portion provided with a first end portion that extends substantially uninterrupted to a second end portion through an intermediate portion. A plurality of mounting elements are provided on the first end portion. A star member is operatively connected to the spool. The star member includes a main body, a plurality of flap members that extend from the main body and collectively define a central opening, and a plurality of mounting members that extend into the central opening. The plurality of mounting members engage with corresponding ones of the plurality of mounting elements to detachably mount the star member to the first end portion of the spool. 
         [0006]    In accordance with another exemplary embodiment, a star member for an electric machine includes a main body, a plurality of flap members that extend from the main body and collectively define a central opening, and a plurality of mounting members that extend into the central opening. 
         [0007]    Additional features and advantages are realized through the techniques of exemplary embodiments of the present invention. Other embodiments and aspects of the invention are described in detail herein and are considered a part of the claimed invention. For a better understanding of the invention with advantages and features thereof, refer to the description and to the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a right perspective view of a spool for an electric machine constructed in accordance with the prior art; 
           [0009]      FIG. 2  is a cross-sectional side view of an electric machine including a spool assembly constructed in accordance with an exemplary embodiment of the invention; 
           [0010]      FIG. 3  is a right perspective view of a spool assembly in accordance with an exemplary embodiment of the invention; 
           [0011]      FIG. 4  is a right perspective view of a spool portion of the spool assembly of  FIG. 3 ; 
           [0012]      FIG. 5  is a right perspective view of a star member of the spool assembly of  FIG. 3 ; and 
           [0013]      FIG. 6  is a right perspective view of the star member of  FIG. 5  mounted to the spool of  FIG. 4 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0014]    With initial reference to  FIGS. 2 and 3 , an electric machine, shown in the form of an automotive alternator, constructed in accordance with exemplary embodiments of the invention is indicated generally at  20 . Electric machine  20  includes a housing  22  having a first surface  23  and a second, opposing surface  24 . A plurality of electrical components  25  are mounted to second surface  24  and are provided with a cover  26 . In addition, electric machine  20  is shown to include a stator  29  having a plurality of steel segments (not separately labeled) and a rotor  32 . Rotor  32  includes a shaft  34  operatively coupled to a pulley  36 , and a spool assembly  38 . As will be detailed more fully below, spool assembly  38  includes a spool  40  wrapped with wire  42  and protected by first and second star members  48  and  50 . In accordance with one aspect of the exemplary embodiment, spool  40  is formed from a non-electrically conducting material, such as nylon, and each star member is formed from a non-conducting sheet of insulation material or laminate. Typically, each star member  48  and  50  is stamped or rolled out of the non-conducting sheet or laminate. In operation, rotor  32  spins within housing  22  adjacent to stator  29 . The motion of rotor  32  causes an electrical current to develop in wire  42 . The electrical current is passed to electrical components  25  for processing. The processed electrical current is then utilized to power various electrical devices. 
         [0015]    Reference will now be made to  FIGS. 3-6  in describing spool assembly  38  constructed in accordance with exemplary embodiments of the invention. As shown, star members  48  and  50  are mounted to spool  40  and manipulated (folded) to provide protection for underlying wire (not shown). In accordance with one aspect of the exemplary embodiment, spool  40  is formed from a readily moldable and electrically insulating material such as, but not limited to, plastic. Towards that end, spool  40  includes a main body portion  60  having a first peripheral end portion  62  that extends to a second peripheral end portion  63  through a substantially un-interrupted intermediate portion  65 . That is, spool  40  is constructed without thick flanges in order to maximize wire carrying capacity of spool assembly  38 . Spool  40  is also shown to include a wire tie off post  67  as well as a first plurality of mounting elements, one of which is indicated at  74 , and a second plurality of mounting elements, one of which is indicated at  76 , for retaining star member  48 . Spool  40  also includes a third plurality of mounting elements, one of which is indicated a  80 , and a fourth plurality of mounting elements, one of which is indicated at  82 , for retaining star member  50 . 
         [0016]    As best shown in  FIG. 4 , each of the first and third pluralities of mounting elements  74  and  80  take the form of a projection, such as shown at  84  in connection with mounting elements  74 , and at  85  in connection with mounting elements  80 . Each projection  84  and  85  extends substantially perpendicularly outward from respective ones of first and second end portions  62  and  63  and is arranged in a spaced relationship about main body portion  60 . In addition, projection  84  includes an ear element  87  and a tab element  88 . Likewise, projection  85  includes an ear element  90  and tab element  91 . Also shown in  FIG. 4 , each of the second and fourth plurality of mounting elements  76  and  82  take the form of slots, such as shown at  93  in connection with second plurality of mounting element  76 , and at  94  in connection with fourth plurality of mounting element  82 . Each slot  93  and  94  is arranged in a spaced relationship about respective ones of first and second end portions  62  and  63 . More specifically, projections  84  and slots  93  are staggered about first end portion  62  while projections  85  and slots  94  are staggered about second end portion  63 . By staggered it should be understood that, for example, projection  84  and slot  93  are arranged in an alternating pattern one after the other about a periphery of first end portion  62 . 
         [0017]    At this point it should be understood that each star member  48  and  50  is similarly formed such that a detailed description will follow referencing  FIG. 5  in describing star member  48  with an understanding that star member  50  includes corresponding structure. As shown, star member  48  is formed from a laminate material such as, but not limited to, a Polyester/meta-aramid or Nomex®/Polyester, or Polyimide/meta-aramid or Nomex®/Polyimide or the like. Star member  48  includes a main body  104  having a central opening  105 . Star member  48  includes a plurality of flap members  110 - 116  that radiate outward from a central opening  105  and a plurality of mounting members, one of which is indicated at  130 , and a plurality of mounting components, one of which is indicated at  132 . Each of the plurality of mounting members  130  takes the form of a prong  137  that extends radially into central opening  105  while each of the plurality of mounting components  132  takes the form of a recess  140  formed in main body  104 . 
         [0018]    Reference will now be made to  FIG. 6  in describing an exemplary construction of spool assembly  38 . As shown, each star member  48  and  50  is mounted to corresponding ones of first and second end portions  62  and  63  of spool  40 . Star member  48  is oriented such that each of the plurality of prongs  137  registers with a corresponding one of the second plurality of mounting elements  76 . In this manner, each of the plurality of recesses  140  registers with a corresponding one of the first plurality of mounting elements  74 . First plurality of mounting elements  74  prevent star member  48  from being moved in a direction away from second end portion  63 , and second plurality of mounting elements  76  prevent star member  48  from moving in a direction toward second end portion  63 . 
         [0019]    More specifically, when star member  48  is properly positioned, each of the first plurality of mounting members  74  nests within a corresponding recess  140 . With this construction, ear elements  87  and tab elements  80  not only contribute to establishing a desired orientation but also prevent any axial/rotational movement of star member  48  relative to a central axis (not separately labeled) of spool  40 . Similarly, star member  50  is secured to spool  40  by third pluralities of mounting elements  80  and a fourth plurality of mounting elements  82 . 
         [0020]    Once star members  48  and  50  are properly positioned, prongs  137  on star member  50  are folded over into an interior surface (not separately labeled) of spool  40 . More specifically, a steel ring  146  is inserted into spool  40  folding and locking prongs  137  to slots  93 . Prongs  137  prevent rotation of star member  48  relative to spool  40 . Steel ring  146  includes a split  148  that ensures a tight engagement with spool  40 . After star members  48  and  50  are locked in position, spool  40  is wrapped with wire. After wrapping with wire, spool assembly  38  is inserted onto a rotor segment core (not separately labeled). Segment fingers (not shown) on the segment core cause flaps  110 - 116  on each star member  48  and  50  to fold over. The segment fingers also cause prongs  137  on star member  48  to fold over into corresponding slots (not separately labeled) formed in steel ring  146  to complete spool assembly  38  such as shown in  FIG. 3 . 
         [0021]    At this point it should be understood that the above exemplary embodiments provide a spool assembly and components of a spool assembly having an enhanced wire carrying capacity while simultaneously eliminating the need for costly and difficult welding operations. That is, by eliminating the large, thick flanges required on prior art spools, the spool, in accordance with the exemplary embodiment, holds a larger volume of wire without increasing in size. 
         [0022]    In general, this written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of exemplary embodiments of the present invention if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.