Abstract:
The present invention provides increased uniformity in the forming of coils wound onto a dynam-electric machine component core by providing an apparatus having a greater number of forming pushers in the same machine core space. The present invention adopts a space saving mechanism for radially driving and retracting the pushers. Two series of pushers are alternately arranged around a central axis. The first series of pushers is capable of being driven radially outwardly and being retracted radially inwardly by the actuation mechanism, while the second series of pushers is only capable of being driven radially outwardly by that mechanism. The first and second series of pushers are provided with overlapping protrusions and recesses, respectively, which enable the radially inward retraction of the first series of pushers to provide the same radially inward retraction for the second series of pushers.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims priority from U.S. provisional patent application No. 60/328,973, filed Oct. 12, 2001, which is incorporated herein in its entirety. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The present specification concerns solutions for forming coils wound onto certain types of cores for dynamo-electric machines. More particularly, the solutions are useful for definite positioning and compacting of coil portions which extend beyond the axial ends of a dynamo-electric machine core, such as is required, for example, in manufacturing alternator stators.  
           [0003]    This positioning and compacting of the coil portions is generally referred to as forming. According to the prior art, such forming operations are obtained by passing an arbor through the central aperture of the machine core and aligning the pushers of the arbor with the external coil portions. These pushers are capable of moving in a radial direction relative to the circumference of the machine core to push against the external coil portions. In general, the pushers compress the external coil portions against a circular abutment member placed at a predetermined radial position around the external coil portions. The amount of movement of the pushers in the radial direction and the compression against the circular abutment member determines the required forming of the external coil portions.  
           [0004]    The pushers in a conventional forming apparatus are positioned extremely close to each other in an attempt to produce uniform compression against the abutment member. Regardless of such efforts, however, forming may not be uniformly obtained. Particularly, some areas of the external coil portions may not be sufficiently expanded in the radial direction and present the unwanted result of extending toward the central opening of the machine core. Another unwanted result may be a lack of uniformity in the formed thickness of the external coil portions, where some areas are successfully expanded in the radial direction and brought to a desired thickness and other areas are not.  
         SUMMARY OF THE INVENTION  
         [0005]    In view of the foregoing, the present invention proposes to reduce the occurrence of such unwanted results using a forming apparatus having a greater number of pushers to form the coils in a machine core of the same size having coils of the same dimensions. By using a greater number of pushers to form the external coil portions, the present invention improves the uniformity of the compression against the abutment member which surrounds the external coil portions.  
           [0006]    In order to increase the number of pushers operating within the same available machine core space, the present invention adopts a space saving mechanism for radially driving and retracting the pushers. To that end, two series of pushers are alternately arranged around a central axis. The first series of pushers is capable of being driven radially outwardly and being retracted radially inwardly by the actuation mechanism, while the second series of pushers is only capable of being driven radially outwardly by that mechanism. The first and second series of pushers are provided with overlapping protrusions and recesses, respectively, which enable the radially inward retraction of the first series of pushers to provide the same radially inward retraction for the second series of pushers. Therefore, the required number of dual-direction connections to the actuation mechanism is reduced, and a greater number of pushers may be used within the same core space to provide better uniformity in forming. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1 is a perspective view of an illustrative stator core  10  wound with one representative undulated coil C;  
         [0008]    [0008]FIG. 2 is a fragmentary view from direction  2  of FIG. 1 of a stator core having all the required coils in the condition of being definitely positioned in radial direction R with thickness  11  in accordance with an illustrative embodiment of the present invention;  
         [0009]    [0009]FIG. 3 is a view from direction  3 - 3  of FIG. 2 of pushers in a radially innermost condition of operation in accordance with the depicted illustrative embodiment of the invention (FIG. 3 and subsequent FIGS. show the coils on the core in a greatly simplified representation);  
         [0010]    [0010]FIG. 4 is a view similar to FIG. 3 showing pushers that have been moved radially outwardly to press coil portions C′ to a required thickness  11  in accordance with the invention;  
         [0011]    [0011]FIG. 4 a  is a magnified representation of area  4   a  in FIG. 4;  
         [0012]    [0012]FIG. 5 is a partial sectional view (taken generally along the line  5 - 5  in FIG. 4, but prior to full radially outward expansion of the annular array of pushers) showing the mechanism for positioning and moving pushers  31  to simultaneously form the coil portions on both ends of the stator core in accordance with the depicted illustrative embodiment of the invention;  
         [0013]    [0013]FIG. 6 is a sectional view taken generally along the line  6 - 6  in FIG. 5;  
         [0014]    [0014]FIG. 7 is similar to FIG. 5, but after radially outward expansion of the annular array of pushers;  
         [0015]    [0015]FIG. 8 is a partial sectional view taken generally along the line  8 - 8  in FIG. 4, but prior to full radially outward expansion of the annular array of pushers; FIG. 8 is generally like FIG. 5, but for pushers  30 ;  
         [0016]    [0016]FIG. 9 is similar to FIG. 8, but after radially outward expansion of the annular array of pushers; and  
         [0017]    [0017]FIG. 10 is a simplified view from direction  10 - 10  of FIG. 6 of the forming apparatus without the stator core and the abutment member in accordance with the depicted illustrative embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]    With initial reference to FIG. 1, the invention is concerned with positioning external portions C′ of coils in radial direction R, and compacting the same external portions C′ to a predetermined thickness  11 . Thickness  11  is transverse to longitudinal axis  10 ′ of the stator core, as is shown in FIG. 1. For sake of clarity, FIG. 1 shows only one of the undulated coils C in the stator core. In practice, however, the positioning and compacting requirements, described previously in terms of positioning in radial direction R and reaching thickness  11 , need to be accomplished through a single operation for all the coils present in the stator core (see, for example, FIG. 2).  
         [0019]    [0019]FIG. 3 is a view from direction  3 - 3  of FIG. 2, augmented with an illustrative embodiment of the annular array of pushers of the present invention, shown in a certain condition of operation. With reference to FIG. 3, the pushers belong to two series. The pushers of the first series are numbered  30 , while the pushers of the second series are numbered  31 . As shown, pushers  30  of the first series are placed around axis  10 ′ at equal angular distances from each other. Similarly, pushers  31  of the second series are interposed between the pushers of the first series, and are consequently also at equal angular distances from each other. Each pusher  30  or  31  is capable of moving along a respective radial direction R of the stator, like directions R shown in FIGS. 1 and 2. The stage of operation shown in FIG. 3 corresponds to a situation in which the pushers have been inserted into the stator core to become aligned with the external portions C′ of the coils at the end of the stator core. In other words, the pushers have moved into the stator core, are aligned with coil portions C′, and are ready to move in radially outward directions R to perform the forming operation.  
         [0020]    Pushers exactly like those shown in FIG. 3 are simultaneously positioned at the opposite end of the stator core and are also ready to move in radially outward directions R to perform the forming operation of coil portions C′ located on the opposite end of the stator core. As will be more fully explained in the following, the pushers  30  and  31  present on one end of the stator core, like those shown in FIG. 3, are duplicated on the opposite end of the stator core. With reference to FIG. 3, the mechanisms for moving and carrying the pushers  30 / 31  have been omitted for sake of clarity, although they will be represented in later FIGS.  
         [0021]    [0021]FIG. 4 is a view similar to FIG. 3 showing the pushers  30 / 31  in a stage where they have been moved outwardly along radial directions R, and have pressed the coil portions C′ to a required thickness  11 . In both FIGS. 3 and 4, stationary abutment member  32  has been schematically represented around the complete circular extension of the coil portions. The abutment member reacts to the pressing forces with which the pushers  30 / 31  are pressing on the coil portions C′ to accomplish forming. Abutment member  32  has been schematically represented as a single circular member, although its actual configuration may be a combination of sector members individually positioned around the coil portions to form the circular shape shown.  
         [0022]    As shown in FIG. 4 a,  which is a magnified representation of area  4   a  of FIG. 4, the pushers  30 / 31  are configured to fit very close to each other. With reference to FIG. 4 a,  representative pusher  31  is provided with portion  31 ′ which fits into a complementary recess  30 ′ of representative, angularly adjacent pusher  30 . In addition, portion  30 ″ of pusher  30  fits into a complementary recess  31 ″ of pusher  31 . A comparison between FIGS. 3 and 4 shows how these portions and recesses are displaced laterally with respect to each other when the pushers are moved along their respective radial directions R.  
         [0023]    Surface  30   a  of pusher  30  and surface  31   a  of pusher  31 , which extend between the previously described recesses and portions, are inclined and transverse to radial directions R to engage extensively against each other when the pushers are moved inwardly opposite radial directions R (i.e., toward the center of the stator core). More particularly, the engagement of surfaces  31   a  and  30   a  will cause the radially inward movement of pushers  31  to move pushers  30  inwardly toward the center of the stator core along radial directions R after forming of the coil portions C′ has occurred.  
         [0024]    [0024]FIG. 5 is a partial sectional view as seen from direction  5 - 5  of FIG. 4 showing the stage of operation represented in FIG. 3. Furthermore, FIG. 5 shows parts which have been omitted in FIGS. 3 and 4 for sake of clarity. FIG. 5 is particularly relevant for showing the mechanisms for positioning and moving pushers  31  for simultaneously forming the coil portions on both ends of the stator core. More particularly, pushers  31  are portions of a single member  50 . In other words, a single member  50  has two pusher portions  31  to simultaneously form the coil portions C′ on opposite ends of the stator core. FIG. 5 shows the mechanism used for moving pusher portion  31  of one angular sector of the stator core (i.e., for one of the pushers  31  shown in FIGS. 3 and 4). As will be more apparent from the rest of the FIGS., particularly from the combination of FIGS. 5 and 6, each set of pushers  31  in an angular sector of the stator core has a respective moving mechanism identical to that depicted in FIG. 5.  
         [0025]    [0025]FIG. 6 is a section view as seen from direction  6 - 6  of FIG. 5 showing that mechanisms like that shown in FIG. 5 are present for all pushers  31 . With reference to FIGS. 5 and 6, single member  50  is fixed to slide  51  by means of bolt  52 . Slide  51  has an inclined key portion  51 ′ which is received in an inclined keyway  53 ′ of cone member  53 . Slide  51  is supported by ledge  54 ′ of support member  54 . Each slide  51  is capable of moving in an associated radial direction R for forming the coil portions as shown in FIG. 4. Each slide  51  is also capable of moving oppositely to the associated radial direction R in order return to the position shown in FIGS. 3 and 5 after the forming operation has occurred. During these movements, each slide  51  is guided by sides  55 ′ of slits  55  present on support member  54 . Ledge  54 ′ of support member  54  corresponds to a bottom side of slit  55 . Single member  50  is also provided with a pushing member  56  located between pusher portions  31 . The pushing member is fixed in a recess of single member  50  by bolts (shown but not numbered). Pushing member  56  is provided with protrusions  56 ′ capable of passing through slot openings of the stator core to press on portions of the coils present in the stator core slots. FIG. 5 is actually showing the mechanism for moving the pusher portions  31  (shown in the rest position prior to moving, or immediately after starting to move in the radially outward direction) to form coil portions C′.  
         [0026]    [0026]FIG. 7 is a view similar to FIG. 5, although showing pusher portions  31  pressing on coil portions C′ after movement of slide  51  has occurred in radial direction R. Radial movement of slide  51  is caused by movement of cone member  53  in vertical direction V. Movement of cone member  53  in vertical direction V causes the surfaces of keyway  53 ′ to push on the surfaces of key portion  51 ′ in radial direction R, thereby causing pusher portions  31  to move in radial direction R and accomplish forming of coil portions C′. FIG. 7 also shows that protrusions  56 ′ of pushing member  55  are pressing on and compacting the coil portion present within the slots of the stator core as a result of the previously described movement in radial direction R.  
         [0027]    [0027]FIG. 8 is a partial sectional view as seen from direction  8 - 8  of FIG. 4, although showing the operation stage of FIG. 3. Furthermore, FIG. 8 also shows parts which have been omitted in FIGS. 3 and 4 for sake of clarity. FIG. 8 is particularly relevant for illustrating the mechanisms used to position and move pushers  30  in radial direction R. Again, pushers  30  are portions of a single member  70 . In other words, a single member  70  will have two pusher portions  30  to simultaneously form the coil portions C′ on opposite ends of the stator core. FIG. 8 shows the mechanism used for moving pusher portions  30  of one angular sector of the stator core (i.e., for one of the pushers  30  shown in FIGS. 3 and 4). As will be more apparent from the rest of the FIGS., particularly from FIG. 6, each set of pusher portions  30  of an angular sector of the stator core has a respective moving mechanism identical to that depicted in FIG. 8.  
         [0028]    With reference to FIGS. 6 and 8, each single member  70 , related to an associated pair of pushers  30 , is fixed to slide  71  by means of bolt  72 . Slide  71  has an inclined engaging surface  71 ′ which is engaged by an inclined planar surface  53 ″ of cone member  53 . Slide  71  is supported by ledge  74 ′ of support member  54 . Slide  71  is capable of moving in radial direction R for forming the coil portions as shown in FIG. 4. Slide  71  is also capable of moving oppositely to radial direction R in order to return to the position shown in FIG. 9 after the forming operation has occurred. During these movements, slide  71  is guided by sides  75 ′ of a slit  75  present on support member  54 . Ledge  74 ′ of support member  54  corresponds to a bottom side of slit  75 . Each single member  70  is also provided with a pushing member  76 . Pushing member  76  is provided with numerous protrusions  76 ′ capable of passing through respective slot openings of the stator core in order to press on and compact portions of the coils that are present in stator core slots. FIG. 8 shows the mechanism for moving pusher portions  30  in the rest position prior to moving in radial direction R to form coil portions C′, or immediately after starting to move in radial direction R to form coil portions C′.  
         [0029]    [0029]FIG. 9 is a view similar to FIG. 8, although showing pusher portions  30  pressing on coil portions C′ after movement of slide  71  has occurred in radial direction R through movement of cone member  53 ′ in vertical direction V. Movement of cone member  53  in vertical direction V causes planar surface  53 ″ of cone member  53  to push engaging surface  71 ′ of single member  71  in radial direction R, thereby causing pusher portions  31  to move in radial direction R to reach the forming condition shown in FIG. 9. FIG. 9 also shows that protrusions  76 ′ of pushing members  76  are pressing on and compacting the coil portion present within the slots of the stator core as a result of the previously described movement in radial direction R.  
         [0030]    [0030]FIG. 10 shows the forming apparatus from direction  10 - 10  of FIG. 6 without representing the stator core and abutment member  32 . FIG. 10 is particularly relevant for showing the configuration of support member  54  which needs to be inserted into the stator core by movement in direction D. Direction D would be parallel to axis  10 ′ of the stator core and axis X of support member  54  would be aligned with axis  10 ′ of the stator core for the insertion to occur. Head  100  is screwed onto the extremity of support member  54 . If the external portions of the coils are in the way when the support member is being inserted into the stator core, head  100  would push the external portions outward to facilitate insertion of the support member. At the completion of the movement in direction D to insert support member  54  in the stator core, pushers  30  and  31  need to be aligned with the respective coil portions C′. Once this condition of alignment has been reached, core member  53  can be moved in direction V to cause all the pushers to simultaneously move radially outwardly to reach the forming condition shown in FIGS. 4 and 4 a.  This simultaneous movement of the pushers is achieved by the mechanisms described with reference to FIGS.  5 - 9 .  
         [0031]    Once forming has been reached, as shown in FIG. 4, the pushers are returned to the position shown in FIG. 3 by moving cone member  53  opposite to direction V. This opposite movement of the core member will move pushers  31  radially inwardly toward axis  10 ′ of the stator core due to the keyway  53 ′ and key portion  51 ′ connection described with reference to FIGS. 5 and 6. Pushers  30  are simultaneously moved radially inwardly with pushers  31  toward axis  10 ′ of the stator core due to the engagement of surfaces  31   a  and  30   a,  described previously with reference to FIG. 4 a.    
         [0032]    Based on the above principles, it has been possible to limit the connection of pushers  30  to core member  53  to the engagement of planar surface  53 ″ with engaging surface  71 ′, as described previously with reference to FIGS. 6 and 8. The engagement of planar surface  53 ″ with engaging surface  71 ′ is a connection solution which requires extremely reduced space occupancy on cone member  53 , thereby making it possible to include a higher number of pushers within the same available stator core space.  
         [0033]    Thus, systems and methods for increasing uniformity in forming operations are provided. One skilled in the art will appreciate that the present invention can be practiced by other than the described embodiment, which is presented for the purpose of illustration and not of limitation.