Abstract:
A method of securing a fan member to a rotor assembly of an electric machine. The method includes positioning the fan member adjacent the rotor, aligning at least two mounting members extending radially outwardly of the central hub of the rotor assembly with a corresponding at least two mounting elements extending radially inwardly of a hub portion of the fan member, and securing the at least two mounting members to the corresponding at least two mounting elements.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a divisional of U.S. patent application Ser. No. 14/021,797, which was filed on Sep. 9, 2013. The entire contents of U.S. patent application Ser. No. 14/021,797 are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Exemplary embodiments pertain to the art of electric machines and, more particularly, to a component for an electric machine. 
         [0003]    Many electric machines include a stator and a rotor that are shifted relative to one another to create an electromotive force. In many cases, a fan is mounted relative to the rotor. In operation, the rotor spins the fan which, in turn, provides a cooling airflow to the electric machine. At present, the particular mounting of the fan to the rotor creates limitations on electric machine size. More specifically, mounting the fan to the rotor requires certain mounting structures on both components. As electric machines become smaller, pulleys and other components are mounted closer to the rotor. The particular structure required for mounting the fan limits the distance that the pulley, or other such components, can be mounted relative to the rotor. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0004]    Disclosed is a method of securing a fan member to a rotor assembly of an electric machine. The method includes positioning the fan member adjacent the rotor, aligning at least two mounting members extending radially outwardly of the central hub of the rotor assembly with a corresponding at least two mounting elements extending radially inwardly of a hub portion of the fan member, and securing the at least two mounting members to the corresponding at least two mounting elements. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
           [0006]      FIG. 1  depicts an electric machine including a rotor assembly and a fan member, in accordance with an exemplary embodiment; 
           [0007]      FIG. 2  depicts a partially disassembled perspective view of the rotor assembly and fan member of  FIG. 1 ; 
           [0008]      FIG. 3  depicts an assembled perspective view of the rotor assembly and fan member of  FIG. 2 ; 
           [0009]      FIG. 4  depicts an assembled perspective view of a rotor assembly and fan member, in accordance with another aspect of the exemplary embodiment; and 
           [0010]      FIG. 5  depicts an assembled perspective view of a rotor assembly and fan member, in accordance with yet another aspect of the exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0011]    A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
         [0012]    With reference to  FIGS. 1-3 , an electric machine, constructed in accordance with an exemplary embodiment, is indicated generally at  2 . Electric machine  2  is shown in the form of an alternator  3  and includes a housing  4  within which is arranged a stator  6  and a rotor assembly  8 . Rotor assembly  8  rotates relative to stator  6  and includes a rotor  10  having a body  14 . Body  14  includes a first half or claw pole portion  15  and a second half or claw pole portion  16 . Each claw pole portion  15  and  16  includes a corresponding plurality of pole members, one of which is indicated at  17 , on first claw pole portion  15  and at  18  on second claw pole portion  16 . In the exemplary embodiment shown, the plurality of pole members  17  on first claw pole portion  15  represents half of a total number of pole members for rotor  10  and the plurality of pole members  18  on second claw pole portion  16  represents another half of the total number of pole members of rotor  10 . 
         [0013]    Rotor  10  includes a central hub  20  and a first projection or mounting member  23  and a second projection or mounting member  24 . In the exemplary embodiment shown, first mounting member  23  is arranged substantially directly opposite to second mounting member  24 . As will become more fully evident below, first and second mounting members  23  and  24  extend radially outwardly from central hub  20 . First and second mounting members  23  and  24  project axially outwardly from first claw pole portion  15  and may include curvilinear outer sides  26  and  27  respectively. It should be evident to those skilled in the art that the shape of the mounting members  23  and  24  may take other forms including rectangular, triangular and the like. Mounting members  23  and  24  may also take the form of a slight radial bulge. Mounting members  23  and  24  extend from first claw pole portion  15  and may terminate prior to an outer edge (not separately labeled) of central hub  20 , may extend beyond the outer edge of central hub  20 , or may be coplanar with the outer edge of central hub  20 . 
         [0014]    In the exemplary embodiment shown, curvilinear outer sides  26  and  27  are substantially semi-circular. Rotor  10  is also shown to include a shaft  30  that extends through first and second claw pole portions  15  and  16 . Shaft  30  extends from a first end  34  to a second end  35  through an intermediate portion  36 . Intermediate portion  36  is rotatably supported to housing  4  by first and second bearings  41  and  42 . A sheave or pulley  44  is mounted to first end  34  of shaft  30 . Pulley  44  is configured to drive or be driven by a belt (not shown). Rotor  10  is further shown to include a fan member  50  arranged adjacent first claw pole portion  15  and a fan component  52  arranged adjacent second claw pole portion  16 . Fan member  50  and fan component  52  are configured to generate a cooling air flow through housing  4 . 
         [0015]    In accordance with an exemplary embodiment, fan member  50  includes a body portion  58  having a hub portion  60  that is surrounded by a substantially planar portion  62 . Fan member  50  includes a plurality of fan blades, one of which is indicated at  64 , that projects radially outwardly from body portion  58 . Each fan blade  64  includes a first portion  66  and a second portion  67 . Second portion  67  is angled relative to first portion  66 . Fan member  50  includes a first mounting element  74  and a second mounting element  75 . Mounting elements  74  and  75  take the form of first and second notches  77  and  78  respectively. Each notch  77  and  78  extends radially outwardly from hub portion  60  into substantially planar portion  62 . Each notch  77  and  78  includes a corresponding discontinuous edge  80  and  81  that create respective interruptions (not separately labeled) in hub portion  60 . In the exemplary embodiment shown, first and second discontinuous edges  80  and  80  are curvilinear. In accordance with an aspect of the exemplary embodiment, first and second discontinuous edges  80  and  81  are substantially semi-circular. 
         [0016]    In this manner, fan member  50  is positioned at first claw pole portion  15  such that hub portion  60  registers with central hub  20 . In accordance with an aspect of the exemplary embodiment, a gap  86  is arranged between central hub  20  and hub portion  60  when fan member  50  is in place. Gap  86  establishes a moat that traps any varnish that might be present on rotor  10 . That is, gap  86  inhibits varnish from migrating into central hub  20  or along shaft  30  which could create a loose fit at bearing  42  or at pulley  44 . First and second mounting elements  74  and  75  are receptive of first and second mounting members  23  and  24 . Mounting members  23  and  24  constrain radial movement of fan member  50  relative to first claw pole portion  15 . Once in position, first and second mounting members  23  and  24  are staked by applying a force to the mounting members  23  and  24 . Staking results in an outward expansion of first and second mounting members  23  and  24  that creates a mechanical bond with fan member  50 . The mechanical bond causes the fan member  50  to be axially constrained relative to first claw portion  15 . 
         [0017]    At this point it should be apparent that by forming the mounting members into the central hub, tooling and production costs can be reduced. Further, by forming the mounting members at the central hub, the number and size of connection points can be reduced. It should also be understood that the number and location of mounting members and corresponding mounting elements can vary.  FIG. 4  shows an electric machine with three mounting elements and three mounting members;  FIG. 5  shows an electric machine with four mounting elements and four mounting members. By minimizing the number of connections between the fan member and the rotor, and by eliminating raised portions about the connection zones, the rotor assembly has a shorter axial dimension. The shorter axial dimension enables electric machine  2  to be formed having a more compact form factor. 
         [0018]    While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims.