Abstract:
A rotor assembly for an electromechanical device includes a molded wire support. The wire support has a body including a first side spaced from a second side and a hole extending through the sides and configured to receive a shaft. The body includes a wall about the hole extending to the first side. At least one end turn support extends outwardly from the wall and is configured to support wires. A molded pocket extends into the wall from the second side without penetrating through to the first side.

Description:
BACKGROUND 
       [0001]    This disclosure relates to a rotor assembly wire support and a method for manufacturing the wire support. 
         [0002]    Some rotary electromechanical devices, such as an aircraft starter/generator, utilize a rotor assembly. One type of rotor assembly includes spaced apart wire supports mounted on a shaft. Each wire support includes end turns about which one or more wires are wrapped to provide a coil supported on the rotor assembly. Typically, a different wire support is used at each end of the rotor assembly. The wire support may also include cooling features to communicate cooling fluid to desired locations within the rotor assembly. 
         [0003]    Wire supports have been machined from a solid block of TORLON. TORLON is a very expensive plastic material, and machining is a time consuming, costly manufacturing process. 
       SUMMARY 
       [0004]    A rotor assembly for an electromechanical device includes a molded wire support. The wire support has a body including a first side spaced from a second side and a hole extending through the sides and configured to receive a shaft. The body includes a wall about the hole extending to the first side. At least one end turn support extends outwardly from the wall and is configured to support wires. A molded pocket extends into the wall from the second side without penetrating through to the first side. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    The disclosure can be further understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
           [0006]      FIG. 1  is a schematic view of an electromechanical device. 
           [0007]      FIG. 2  is a perspective view of a rotor assembly. 
           [0008]      FIG. 3  is a top elevational view of the rotor assembly shown in  FIG. 2 . 
           [0009]      FIG. 4A  is a top perspective view of one wire support for the rotor assembly having a wire winding schematically depicted. 
           [0010]      FIG. 4B  is a cross-sectional view of the wire support taken along line  4 B- 4 B in  FIG. 4A . 
           [0011]      FIG. 4C  is a cross-sectional view of the wire support shown in  FIG. 4A  illustrated on a shaft of the rotor assembly. 
           [0012]      FIG. 5A  is a cross-sectional view of the wire support taken along line  5 A- 5 A in  FIG. 4A . 
           [0013]      FIG. 5B  is a cross-sectional view of the wire support taken along line  5 B- 5 B in  FIG. 5A . 
           [0014]      FIG. 5C  is a cross-sectional view of the wire support taken along line  5 C- 5 C in  FIG. 5A . 
           [0015]      FIG. 5D  is a bottom elevational view of the wire support shown in  FIG. 5A . 
           [0016]      FIG. 5E  is an enlarged view taken from  FIG. 5D . 
           [0017]      FIG. 6A  is a cross-sectional view of another example wire support similar to the wire support illustrated in  FIG. 4A . 
           [0018]      FIG. 6B  is a cross-sectional view of the wire support taken along line  6 B- 6 B in  FIG. 6A . 
           [0019]      FIG. 6C  is a cross-sectional view of the wire support taken along line  6 C- 6 C in  FIG. 6A . 
           [0020]      FIG. 6D  is a bottom elevational view of the wire support shown in  FIG. 6A . 
           [0021]      FIG. 7  is a schematic view of an injection molding process used in manufacturing the example wire supports. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    An electromechanical (EM) device  10 , such as a starter/generator, is schematically illustrated in  FIG. 1 . The EM device  10  is rotationally coupled to a primary mover  12 , such as an aircraft engine, to receive and/or impart rotation from and to the primary mover  12 . 
         [0023]    The EM device  10  includes a rotor assembly  14  having a shaft  16  rotatable about an axis  18 . A stator  22  is arranged within a housing  20  about the rotor assembly  14 . Wire supports  26 ,  126  are provided on the rotor assembly  14  for supporting wire windings  46  ( FIGS. 1-4B ). The wire windings  46  impart a current in the stator  22  and/or receive rotational input from current in the stator  22 , depending upon the application. The stator  22  may be a wire coil or permanent magnet. 
         [0024]    Referring to  FIGS. 2-4C , the wire supports  26 ,  126  are arranged on opposing portions of the shaft  16 . In the example, a spacer  28  is provided on the shaft  16  to maintain the wire supports  26 ,  126  in a desired axial spacing. Each wire support  26 ,  126  includes four end turn supports  34  circumferentially spaced from one another about the wire support body and circumferentially aligned with the opposing end turn supports  34 . It should be understood, however, that the end turn supports may be configured in a manner other than disclosed and still fall within the claims. 
         [0025]    Wire winding  46  are wrapped around the end turns  34  (shown by dashed lines in  FIGS. 1 and 2 ) to provide a wire coil. In one example, a sleeve  24  is provided on the shaft  16  adjacent to each of the wire supports  26 ,  126 . The wire supports  26 ,  126  also act as cooling manifolds. The shaft  16  includes a cavity  30  that carries a cooling fluid, such as oil. One or more supply holes  32  in the shaft  16  communicate cooling fluid to an annulus  36  recessed from a central hole  31  in the body, which extends through the body from a first side  62  to a second side  64 . A wall  40  extends axially away from the second side  64  to provide the first side  62 . A depression  42  in the wall  40  adjoins a recess  44  in each end turn  34 , for example. An orifice  38  extends from the annulus  36  to the depression  42  for communicating cooling fluid from the cavity  30  to the end turn supports  34  where the cooling fluid can extract heat from the coil. 
         [0026]    The rotor assembly  14  includes laminations  48  extending between spaced apart containment bands  50  surrounding the wire supports  26 ,  126 . Fasteners  52  and tabs  54  thread into the laminations  48  to trap the wire bundles  46  on the wire support  26  in a desired position relative to the shaft  16 . 
         [0027]    The wire support body provides lobes  72  arranged between the end turn supports  34 . Thus, in the example, the body provides four lobes with each lobe  72  arranged between an adjoining pair of end turn supports  34 . The wire support  26  ( FIGS. 4A-5E ) is configured to support wire ends  58 . In the example, each lobe  72  includes a pair of threaded holes  56  that is adapted to receive a fastener  60  used to secure a wire end  58  to the wire support  26 , as shown in  FIGS. 2-4A  and best shown in  FIG. 3 . Multiple holes  56  enable the wire ends  58  to be secured at different locations depending on the method of winding the coil about the end turn supports  34 . The other wire support  126  does not support any free wire ends in the example. As a result, the example rotor assembly  14  uses two different wire supports  26 ,  126  having different dimensions at various locations, which is discussed in more detail subsequently. 
         [0028]    The wire support  26  is shown in more detail in  FIGS. 5A-5E . The wire support  26  includes molded cavities that prevent undesired cracking, wrapage or shrinkage during molding to facilitate molding the wire support  26  from a plastic material, such as TORLON. In the example, first and second pockets  76 ,  78  are provided in the lobes  72  and extend from the second side  64  into the body, but not all the way through to the first side  62  in the example. The wall  40  is bounded by an outer perimeter  70  and the hole  31 . An intermediate wall  74  separates the first and second pockets  76 ,  78 . The intermediate wall  74  has a thickness of approximately 0.200 to 0.240 inch (5.080 to 6.096 mm) in one example, and in one example 0.150 inch (3.810 mm). An example radial thickness of the outer wall  68  is approximately 0.185 to 0.200 inch (4.699 to 5.080 mm). In the example, an orifice  38  is provided at the intermediate wall  74 . Inner and outer walls  66 ,  68  adjoin the intermediate wall  74  and define the shape of the first and second pockets  76 ,  78 , which are symmetrical in the example. An example radial thickness of the inner wall is approximately 0.125 to 0.170 inch (3.175 to 4.318 mm). 
         [0029]    In the example, each of the first and second pockets  76 ,  78  include a base portion  80  and an inner portion  82  that is smaller than the base portion  80 , resulting in a shoulder  92 . The axial thickness of the shoulder  92  to the bottom of the annulus  36  is 0.080 to 0.165 inch (2.032 to 4.191 mm) in one example. The shoulder  92  includes radii  91  where it meets the inner, outer and intermediate walls  66 ,  68 ,  74 . The radii  91  within the first and second pockets  76 ,  78  are around 0.030 to 0.090 inch (0.762 to 2.286 mm), for example. The inner portion  82  is further recessed into the body from the second side  64  than the base portion  80  and extends axially in the direction of the holes  56 . As best seen in  FIG. 5E , the base and inner portions  80 ,  82  share a common intermediate surface  94  that extends in a generally axial direction. As appreciated from the sections, the holes  56  overlap the base portions  80  but do not extend through to the base portions  80 , for example. 
         [0030]    In the example, the base portion  80  has a generally triangular cross-section and includes first, second and third radii  84 ,  86 ,  88  at the vertices. In one example, the first radius  84  is approximately 0.060 to 0.090 inch (1.524 to 2.286 mm) (as indicated in  FIG. 5E ). The second radius  86  is approximately 0.060 to 0.090 inch (1.524 to 2.286 mm), and the third radius  88  is approximately 0.060 to 0.090 inch (1.524 to 2.286 mm), for example. The inner portion  82  is generally quadrangular in shape and includes a fourth radius  90  at its corners that is approximately 0.035 to 0.060 inch (0.889 to 1.524 mm), for example. 
         [0031]    The wire support  126  is shown in more detail in  FIGS. 6A-6D . Like numerals are used to indicate like features within the Figures. The wire support  126  is similar to the wire support  26 . The wire support  126  has a smaller hole  131 , resulting in a larger annulus  136 . In another example of differences, the wire support  126  does not include the wire end attachment features. Thus, the molded cavities in the wire support  126  may be of a different shape and size. 
         [0032]    In the example, first and second pockets  176 ,  178  are provided in the lobes  172  and extend from the second side  164  into the body, but not all the way through to the first side  162  in the example. The wall  140  is bounded by an outer perimeter  170  and the hole  131 . An intermediate wall  174  separates the first and second pockets  176 ,  178 . The intermediate wall  174  has a thickness of approximately 0.200 to 0.240 inch (5.080 to 6.096 mm) in one example. In the example, an orifice  138  is provided at the intermediate wall  174  and communicates cooling fluid to the depression  142  and recess  144  at the perimeter  170 . Inner and outer walls  166 ,  168  adjoin the intermediate wall  174  and define the shape of the first and second pockets  176 ,  178 , which are symmetrical in the example. An example radial thickness of the inner wall is approximately 0.125 to 0.170 inch (3.175 to 4.318 mm). 
         [0033]    In the example, each of the first and second pockets  176 ,  178  include a base portion  180  and an inner portion  182  that is smaller than the base portion  180 , resulting in a shoulder  192 . The axial thickness of the shoulder  192  to the bottom of the annulus  136  is at least 0.124 inch (3.15 mm) in one example. The shoulder  192  includes radii  191  where it meets the inner, outer and intermediate walls  166 ,  168 ,  174 . The  191  radii within the first and second pockets  176 ,  178  are around 0.030 to 0.090 inch (0.762 to 2.286 mm), for example. The inner portion  182  is further recessed into the body from the second side  164  than the base portion  180  and extends axially in the direction of side  126 . As best seen in  FIG. 6D , the base and inner portions  180 ,  182  share a common intermediate surface  194  that extends in a generally axial direction. 
         [0034]    In the example, the base portion  180  has a generally quadrangular cross-section include first, second, third and fourth radii  184 ,  186 ,  188 ,  189  at the corners. In one example, the first radius  184  is approximately 0.060 to 0.090 inch (1.524 to 2.286 mm) (as indicated in  FIG. 6D ). The second radius  186  is approximately 0.060 to 0.090 inch (1.524 to 2.286 mm), and the third radius  188  is approximately 0.060 to 0.090 inch (1.524 to 2.286 mm), for example. The fourth radius  189  is approximately 0.060 to 0.090 inch (1.524 to 2.286 mm). The inner portion  182  is generally triangular in shape and includes fifth and sixth radii  190 ,  196  at its corners that are respectively approximately 0.035 to 0.060 inch (0.889 to 1.524 mm), for example. 
         [0035]    A molding process  100  is schematically shown in  FIG. 7 . In one example, the molding process  100  includes an injector  108  that injects a melt-flowable plastic into a mold cavity  106  provided by first and second molds  102 ,  104 . More or fewer molds may be used. The cavity  106  includes features that are of a complementary shape to the pockets formed in the wire supports. Features such as the annulus, orifices and holes also may be molded or may be later machined, as desired. 
         [0036]    Although an example embodiment has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of the claims. For that reason, the following claims should be studied to determine their true scope and content.