Abstract:
An assembling apparatus for assembling rotating electrical machines having permanent magnets and armatures cores. The apparatus holds the armature core while the permanent magnets are assembled on to it thus avoiding hand labor. At all times, the rotor is supported so that it cannot cant relative to the stator and its permanent magnets and thus, no damage to the magnets or any coating thereon or to the armature will occur.

Description:
BACKGROUND OF INVENTION  
         [0001]    This invention relates to an assembling apparatus for a rotating electrical machine having permanently magnetized field magnets and more particularly to an improved mechanism for assembly such machines with a minimum of hand operation.  
           [0002]    Many types of rotating electrical machines include a stator, which has affixed to its inner shell a plurality of circumferentially spaced permanent magnets. These permanent magnets cooperate with windings that are formed on a rotor that is juxtaposed to and rotates within the stator case. Obviously, the permanent magnets have a fairly large magnetic flux and this makes manual assembly of the stator case around the rotor difficult. The reason for this is that as the armatures of the rotor move into proximity with the permanent magnets of the stator case, they will be attracted and cause physical contact. This requires considerable strength of the assembler&#39;s hands in order to prevent such contact or the permanent magnets and/or rotor could be damaged.  
           [0003]    It has been the practiced to provide a rust proof surface treatment on the magnets;  
           [0004]    particularly in the use of neodymium-iron-boron magnets and any contact will cause this coating to be displaced. This can result in deterioration of the rust proofing quantities of the device.  
           [0005]    It is, therefore, a principal object to this invention to provide an improved apparatus for assembling such rotation machines wherein the operator need not hold the components in spaced relationship when they are axially moved into registry with each other and so that the components will be held against engagement with each other during this assembling technique.  
         SUMMARY OF INVENTION  
         [0006]    This invention is adapted to be embodied in an assembling apparatus for permanent magnet rotating electrical machines. The electrical machine includes a generally cylindrical stator case having permanent field magnets secured to an inside surface of the stator case and a rotor that is journalled by paired front and rear end closures attached to the stator case. The assembling apparatus comprises a jig for assembling and holding one end of the rotor and one of the end closures. A rotor holder smaller than the internal diameter of the stator is provided for holding the other end of the rotor in alignment with the rotational axis of the rotor. A stator case holder holds the stator case and is supported for movement along the rotor axis while holding the stator case. A driver is provided for assembling the stator case to the one end closure by relatively moving the stator case along the rotor axis while holding the other end of the rotor with the rotor holder. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0007]    [0007]FIG. 1 is a side elevational view of a rotating electrical machine of the type, which can be assembled by the assembling apparatus hereof, with a portion broken away and shown in section.  
         [0008]    [0008]FIG. 2 is an end view of the machine looking in the direction of the arrow  2  in FIG. 1.  
         [0009]    [0009]FIG. 3 is a cross sectional view taken through the stator case sharing the attached permanent magnets.  
         [0010]    [0010]FIG. 4 is a cross sectional view taken along the line  4 - 4  of FIG. 3.  
         [0011]    [0011]FIG. 5 is a side elevational view of the assembling apparatus showing in solid lines the condition prior to assembly of the stator case onto a supported rotor and associated end closure and intermediate positions in phantom.  
         [0012]    [0012]FIG. 6 is a view looking generally in a direction perpendicular to that of FIG. 5 and shows the assembling apparatus partially broken away to indicate the relation of the components to each other.  
         [0013]    [0013]FIG. 7 is a cross sectional view taken along the line  7 - 7  of FIG. 5.  
         [0014]    [0014]FIG. 8 is a view looking generally in the same direction as FIG. 6 and shows the first step in the assembling procedure.  
         [0015]    [0015]FIG. 9 is a view, in part similar to FIG. 8, and shows the second step in the assembly operation.  
         [0016]    [0016]FIG. 10 is a view, in part similar to FIGS. 8 and 9, and shows the final step in the assembly operation of the stator case to the one end cap. 
     
    
     DETAILED DESCRIPTION  
       [0017]    Referring now in details to the drawings and initially primarily to FIGS. 1 and 2, a starter motor that is assembled by a method and apparatus embodying the invention is indicated generally by the reference numeral  21 . The starter motor is adapted to provide electrical starting of an associated internal combustion engine (not shown). Although the invention is described in conjunction with the starter motor, from the foregoing description, it should be apparent that the invention may also be utilized with other types of rotating electrical machines such as electrical generators or alternators.  
         [0018]    The starter motor  21  includes a cylindrical housing  22  which also forms a magnet carrier, as will become apparent. To this end, permanent magnets  23  are affixed by adhesive bonding in circumferentially spaced locations around a cylindrical inner surface portion of the outer housing  22 . (See also FIGS. 3 and 4) The permanent magnets are formed from a magnetic material having a high flux density such as neodymium-iron-boron. Preferably the method described in the copending application entitled “ROTATING ELECTRICAL MACHINE WITH PERMANENT MAGNETS AND METHOD OF MAKING SAME”, Ser. No. ______, filed Feb. 22, 2001 and assigned to the assignee hereof may be used for this purpose, although other methods are possible.  
         [0019]    The outer housing  22  is closed at opposite ends by means of end plates or closures 24  and  25 . The end plates  24  and  25  are fixed to the cylindrical housing  22  by means of a pair of elongated bolts or threaded fasteners  26 , which are threaded into lugs formed on the end plate  25 .  
         [0020]    A rotor, indicated generally by the reference numeral  27  is journalled in the starter motor housing by means of bearings  28  and  29  carried by the end plates  24  and  25 , respectively.  
         [0021]    An oil seal  31  is disposed adjacent the front bearing  29  while the rear bearing  28  is provided in a blind bore in the end plate  24 .  
         [0022]    The rear end plate  24  has a pair of lugs  32  that are formed with openings so as to receive fasteners for affixing it to the associated engine or body of the associated vehicle.  
         [0023]    The rotor  27  is provided with a plurality of coil windings  33  that cooperate with the permanent magnets  23 . Electrical current is fed to these windings by means of a commutator  34  that is fixed forwardly of the windings  33  and which cooperates with brushes mounted on a brush holder  35  as is known in the art. The rotor  27  has a portion  36  that protrudes from the front end plate  25  for cooperation with a flywheel starter gear (not shown) of the associated engine for its starting in a well known manner.  
         [0024]    The front end plate  25  is provided with an electrical fitting  37  for passing an electrical cable  38  that supplies electrical current to the windings  33  of the rotor  27  through the brushes. A terminal post  39  provides one of these electrical connections through a conductor  41  that is insulated from the stator case outer housing  22  by an insulating sleeve  42 . The conductor  41  supplies electrical power to the brushes (not shown) from a terminal plate  43 . The other connection is provided by grounding of the housing  32  to the vehicle body or engine, in a manner well known in this art.  
         [0025]    The apparatus for practicing the invention is shown in detail in FIGS. 5 through 10 and will now be referred to with respect to those figures. This apparatus is indicated generally by the reference numeral  44  and includes a pair of transversely spaced vertically extending guide rods  45  that are mounted on a table mechanism  46  at one side of a conveyor mechanism  47 .  
         [0026]    The table mechanism  46  is moveable as shown by the arrows in FIG. 5 toward and away from the conveyor mechanism  47 , which has a path movement indicated by the arrows in FIG. 6 that extends transversely to the direction of reciprocation of the table mechanism  46 .  
         [0027]    A pair of tubular cylinders  48  are slidably supported upon the guide rods  45  as shown by the arrows in FIG. 5 and are connected to a pair of transversely extending support arms  49  and  51  which extend toward and above the conveyor  47  in the loading position as seen in FIGS. 5 and 6 as well as FIGS. 8 through 10.  
         [0028]    The support plate  49  carries at its outer end a guide bushing  52  through which a support rod  53  extends. The support rod  53  depends downwardly toward the conveyor  47 .  
         [0029]    The lower support plate  51  carries a gripping jaw mechanism, indicated generally by the reference numeral  54 , which is shown in most detail in FIG. 7 comprised of a cylinder  55  having a pair of oppositely extending piston rods  56  which are connected to gripping jaws  57  for moving the gripping jaws  57  as shown by the arrows in FIG. 7 between an opened position as shown in solid lines to a closed position.  
         [0030]    In this closed position, circumferential bearing surfaces  58  of the gripping jaws  57  are received in a groove  59  that is formed in the cylindrical stator casing  22  at a position axially spaced from the magnets  23 .  
         [0031]    As seen in FIG. 6, the top support plate  49  has attached to it, between the posts  45 , an actuating rod  61  of a pneumatic cylinder  62 . This pneumatic cylinder  62  is, in turn, mounted on a cross piece  63  that is fixed to the tops of the support rods  45 . Hence, when the piston rod  61  is extended, the support plates  49  and  51  and the mechanism carried by them will move upwardly and downwardly relative to the conveyor  47  in a direction as indicated by the arrows in FIGS. 5 and 8 through  10 .  
         [0032]    The guide rod  53 , which is journalled within the bearing  52  of the upper plate  49 , carries at its lower end a fixture  64 , which, in turn, supports a rotor support  65 . The rotor support  65  is formed from a plastic material and has a cylindrical outer surface that is of a larger diameter than the inner diameter of the permanent magnets  23 . A lower end  66  of the rotor support  64  is formed with a shape complementary to one of the end plates and particularly the first end plate  24  of the starter motor  21 .