Abstract:
An apparatus for shaping coil ends of a generator&#39;s stator having a plurality of sets of U-shaped large and small conductor segments. The apparatus includes four twister cylinders holding connection ends of the large and small conductor segments in four radial layers at an axial end of the stator, a rotating mechanism rotating the twister cylinders alternately in opposite directions, an elevating mechanism moving the twister cylinders in the axial direction of the stator, and a controller synchronously controlling the rotating mechanism and elevating mechanism.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]    The present application is based on and claims priority from Japanese Patent Application Hei 10-258783, filed Sep. 11, 1999, the contents of which are incorporated herein by reference. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to an apparatus and a method for manufacturing a stator of a rotary electric machine and, particularly, a method and an apparatus for shaping conductor members of a stator of an AC generator for a vehicle.  
           [0004]    2. Description of the Related Art  
           [0005]    Recently, an AC generator&#39;s stator for a vehicle is equipped with a plurality of U-shaped conductor segments to satisfy the demand for increase in power supply.  
           [0006]    PCT application 92/06527 discloses a method of manufacturing such a stator. Conductor members in radially outside and inside layers of the slots of a generator&#39;s stator are bent by a bending tool in circumferential directions first and, subsequently, bent in radial directions to connect each of the conductor members in the outside layer to one of the inside layer. Because the conductor members are not held by the tool after the bending rotation, the coil-ends of the stator winding can not be formed as compact as possible.  
           [0007]    Although JP-A-60-241748 discloses an apparatus which bends the conductor members in both circumferential and radial directions. However, this apparatus has a projection member for forming electrical insulation spaces between the conductor members, and this may cause damage to the surface of the conductor members.  
         SUMMARY OF THE INVENTION  
         [0008]    A main object of the invention is to provide an improved apparatus for shaping the conductor members of a rotary-electric-machine stator.  
           [0009]    Another object of the invention is to provide a new apparatus of shaping the conductor members without causing damage to the conductor members.  
           [0010]    Another object of the invention is to provide a new apparatus of shaping the conductor members that is applicable various types of the stator.  
           [0011]    According to a preferred embodiment of the invention an apparatus for shaping a plurality of conductor members of a rotary-electric-machine stator including first means for holding the conductor members, second means for moving the first means in the circumferential direction of the stator, and third means for moving the first means in the axial direction of the stator. The first means preferably includes a pair of twister cylinders coaxially disposed with each other. Each of the pair of twister cylinders rotates in a direction opposite to each other. Each of the pair of twister cylinders has a plurality of holes disposed circumferentially at equal intervals, and the plurality of holes of one of the twister cylinder is radially spaced apart from the plurality of holes of the other at a first distance.  
           [0012]    Another object of the invention is to provide an improved method for shaping the conductor members of a rotary-electric-machine stator.  
           [0013]    According to a preferred embodiment of the invention, a method for manufacturing a rotary-electric-machine-stator including steps of inserting a plurality of a set of U-shaped large and small conductor segments into stator&#39;s slots in four radial layers, holding each end of the conductor segments in four circumferential layers, circumferentially and radially moving each end of the conductor segments so that the length of the conductor segments extending from the stator can be maintained constant to position each pair of ends of the large and small conductor segments in outer two of the circumferential layers side by side and each pair of ends of the large and small conductor segments in inner two of the circumferential layers side by side, and welding each end of the conductor members positioned side by side. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    Other objects, features and characteristics of the present invention as well as the functions of related parts of the present invention will become clear from a study of the following detailed description, the appended claims and the drawings. In the drawings:  
         [0015]    [0015]FIG. 1 is a perspective view illustrating a stator core and a set of conductor segments to be inserted into a pair of slots;  
         [0016]    [0016]FIG. 2 is a fragmentary cross-sectional view of the stator core having conductor members disposed in the slots thereof;  
         [0017]    [0017]FIG. 3 is a schematic diagram illustrating a shaping apparatus according to a preferred embodiment of the invention;  
         [0018]    [0018]FIG. 4 is a schematic diagram illustrating a set of twister cylinders of the shaping apparatus illustrated in FIG. 4;  
         [0019]    [0019]FIG. 5 is a graph showing motion of the twister cylinder;  
         [0020]    [0020]FIG. 6 is a perspective view of a set of conductor segments after being shaped; and  
         [0021]    [0021]FIG. 7 is a fragmentary perspective view of coil-ends of the stator. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0022]    As shown in FIG. 1, stator core  1  has thirty six slots  2 , and a set  3  of U-shaped large and small conductor segments  31  and  32  is inserted into each pair of the slots  2  spaced apart from each other by one pole-pitch (or three slots in this case) to form a three-phase stator winding.  
         [0023]    As shown in FIG. 2, in-slot portions  31   a ,  32   a  of one set  3  are inserted into two inside layers of a slot  2 , and in-slot portions  32   a′ ,  31   a′  of another set  3  are inserted into two outside layers of the same slot. Insulation film  4  surrounds all in-slot portions  31   a ,  32   a ,  32   b′ ,  31   b′  in four layers to insulate the same from stator core  1 .  
         [0024]    After all sets  3  of segments  31 ,  32  are inserted into thirty six slots of stator core  1 , the straight portions of segments  31 ,  32  extending from stator core  1  are shaped by shaping apparatus  5  shown in FIG. 3. Shaping apparatus includes work support  51 , holder  52 , presser  53 , shaping unit  54 , elevating shaft  54   a , elevating mechanism  54   b , rotating mechanisms  541   a ,  542   a ,  543   a ,  544   a , and controller  54   b.    
         [0025]    Work support  51  supports the peripheral corner of stator core  1 , holder  52  holds the outer periphery of stator core  1 , presser  53  presses and hold down stator core  1 , twisting unit  54  holds connection ends  31   d ,  31   e ,  32   d ,  32   e  of large and small segments  31 ,  32 , elevating shaft  54   a  and elevating mechanism  54   b  move twisting unit  54  up or down, rotating mechanisms  541   a - 544   a  rotate twisting unit  54 , and controller  54   b  controls elevating mechanism  54   b  and rotating mechanisms  541   a - 544   a.    
         [0026]    Twisting unit  54  is composed of four twister cylinders  541 ,  542 ,  543  and  544  coaxially disposed to be telescopically coupled with each other, so that each twister cylinder can rotate separately about the same axis. Each twister cylinder has an annular flange engaged with one of rotating mechanisms  541   a - 544   a . Upper ends of twister cylinders  541 - 544  are leveled with one another, and respectively have a plurality of circumferentially equal-spaced catch holes  541   b ,  542   b ,  543   b    544   b , which are respectively located to correspond to connection ends  31   e ,  32   e ,  32   d  and  31   d.    
         [0027]    Outer connection ends  31   e  of large segments  31  extending from the outermost layer of slots  2  are inserted into catch holes  541   b  of twister cylinder  541 , outer connection ends  32   e  of the small segments  32  extending from the layer adjacent to the outermost layer are inserted into catch holes  542   b  of twister cylinder  542 , inner connection end  32   d  of small segments  32  extending from the layer adjacent to the innermost layer are inserted into catch holes  543   b  of twister cylinder  543 , and inner connection end  31   d  of large segments  31  extending from the innermost layer are inserted into catch holes  544   b  of twister cylinder  544 .  
         [0028]    As shown in FIGS. 4 and 7, each of catch holes  542   b  of twister cylinder  542  adjacent to outermost twister cylinder  541  is radially spaced apart from any of catch holes  541   b  at a distance d 1  which is suitable to weld the adjacent connection ends  31   e′  and  32   e , each of catch holes  543   b  of twister cylinder  543  adjacent to twister cylinder  542  is radially spaced apart from any of catch holes  542   b  at a distance d 2  which is suitable to insulate the adjacent connection ends  32   e  and  32   d , each of catch holes  544   b  of innermost twister cylinder  544  adjacent to twister cylinder  543  is radially spaced apart from any of catch holes  543   b  at a distance d 3  which is suitable to weld the adjacent connection ends  32   d  and  31   d ′, and, naturally, distance d 2  is larger than distance d 1  or distance d 3 .  
         [0029]    Stator core  1  with all the segments inserted into the slots is placed on support  51  and held tightly by holder  52 . Then, stator core  1  is pressed by presser  53  on the upper peripheral corner thereof and the top of turn portions  31   c  of large segments  31 .  
         [0030]    Subsequently, elevating shaft  54   a  elevates twisting unit  54  to a suitable position to insert the chamfered connection ends  31   d ,  31   e ,  32   d , or  32   e  into the catch holes as described above.  
         [0031]    Then, elevating shaft  54   a  is controlled by controller  55  to moved up and down in synchronism with rotation of the twister cylinders as illustrated in FIG. 5, so that the length of the conductor members extending from the slots can be maintained constant. Twister cylinder  541  that holds connection ends  3 l e  extending from the outermost layer and twister cylinder  543  that holds connection end  32   d  extending from the layer next to the innermost layer rotate counterclockwise as indicated by an arrow al in FIG. 4. At the same time, twister cylinder  542  that holds connection ends  32   e  extending from the layer next the outermost layer and twister cylinder  544  that holds connection end  31   d  extending from the innermost layer rotate clockwise in FIG. 4.  
         [0032]    As shown in FIG. 5, while each twister cylinder rotates within an angle θ1, elevation shaft  54   a  and each twister cylinder does not move up significantly. Elevation shaft  54   a  moves up to a position of height H 2  that corresponds to the height of the coil ends when each twister cylinder rotates by angle θ3 that corresponds to a half pole-pitch position and to a top position of height H 1  that is higher the position H 2  when each twister cylinder rotates farther to a position of an angle θ2. Each twister cylinder returns from the position of angle θ2 to the position of angle θ3 after each twister cylinder is elevated to the top position Hi to take out connection ends  31   d ,  31   e ,  32   d ,  32   e  from twister cylinders  541 - 544 . This step prevents spring back of the bent portions of the segments and moves each of connection ends  31   d ,  31   e ,  32   d ,  32   e  along a circular locus, thereby providing a stator winding with small coil ends. Although the twister cylinders are elevated beyond the height of the coil ends, the segments do not fall out from the stator core because they are elevated after they are bent to cling onto the stator core.  
         [0033]    Thus, each set  3  of large and small segments  31  and  32  is formed as shown in FIG. 6: large segment  31  has in-slot portion  31   a , turn portion  31   c , and chamfered connection ends  31   d ,  31   e  formed at the opposite ends thereof; small segment  31  also has in-slot portion  32   a , turn portion  32   c , and chamfered connection ends  32   d ,  32   e  formed at the opposite ends thereof; turn portion  32   c  of small segment  32  is surrounded by turn portion  31   c  of large segment  31 .  
         [0034]    Thereafter, twisting unit  54  is returned to the original position, and holder  52  is removed to unload the stator core with the shaped segments as shown FIG. 7 is unloaded from the shaping apparatus.  
         [0035]    Accordingly, no projection member forming electrical insulation spaces stated before, which otherwise, causes damage to the surface of the conductor members is necessary.  
         [0036]    The shaping apparatus can be applied to various types of stators only by changing the twister cylinders.  
         [0037]    Subsequently, connection ends  31   d ,  31   e ,  32   d ,  32   e  adjacent to each other are welded to form the three-phase stator winding.  
         [0038]    In the foregoing description of the present invention, the invention has been disclosed with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes may be made to the specific embodiments of the present invention without departing from the broader spirit and scope of the invention as set forth in the appended claims. Accordingly, the description of the present invention in this document is to be regarded in an illustrative, rather than restrictive, sense.