Abstract:
An apparatus and method for winding dynamoelectric machine field windings including a winding tool supported for longitudinal and rotational movement relative to a stator supported by a stator nest assembly. Upper and lower wire holders are supported on the winding, tool and are slidably movable relative to the winding tool. The upper and lower wire holders are located on opposite sides of a stator to be wound and are biased by compression springs in a direction toward a respective end of the stator. As the winding tool reciprocates in a longitudinal direction, the upper and lower wire holders alternately engage the upper and lower ends of the stator to alternately clamp upper and lower end loops of field windings being formed by the apparatus.

Description:
RELATED APPLICATION 
     This Application claims the benefit of U.S. Provisional Application Ser. No. 60/127,025, filed Mar. 31, 1999, which application is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to an apparatus for winding dynamoelectric machine field windings and, more particularly, to such an apparatus including a mechanism for preventing the field windings from moving out of a desired position on a stator during a winding operation. 
     2. Related Prior Art 
     Stator coil winding, machines are well known that use a moving wire dispensing element for dispensing wire into stator core slots from end to end of the stator core, passing over the end of the core and to an appropriate return slot, returning axially to the opposite core end, and continuing this motion until the coil is completed. One recognized shortcoming of such winding operations is the tendency of the wire forming the coil to move out of the slots of the stator core radially inwardly toward the interior of the stator core, such as may result from tension applied to the wire as the dispensing element is moved between the stator core ends to position the wire in a slot, which may interfere with the proper performance of the winding operation, result in misformed coils, as well as reduced slot fill. 
     The prior art has proposed various mechanisms for overcoming the problem associated with movement of the wire windings during the winding operation. For example. U.S. Pat. No. 3,414,204 to Friedrich discloses providing wire guiding fingers located adjacent end faces of a stator being wound. In operation, wire is wound over the fingers whereby the wire is held in a desired position as the stator is being wound. 
     In an alternative approach, shroud members are provided on either end of a stator wherein the shroud members define guiding surfaces for guiding wire into the stator core slots and for preventing the wire from falling to the interior of the stator core, such as is disclosed in U.S. Pat. No. 3,648,938 to Dryburgh. 
     U.S. Pat. No. 4,498,636 to Boesewetter discloses a further approach to maintaining the field windings within the stator core slot wherein a cylindrical winding tool is formed to closely fit within the interior of the stator core and includes opposing ends extending beyond the ends of the stator core such that the winding tool effectively closes off the slot openings to prevent wire from exiting into the interior of the stator core during the winding operation. However, this approach does not control movement of wire in the stator core slots to prevent displacement toward the central portion of the stator which can result in reduced slot fill. 
     Accordingly, in spite of the above described mechanisms for improving the operation of forming dynamoelectric field windings, there is a continuing need for a simple and effective mechanism for maintaining the field windings immovably in place on the stator core during the winding operation. 
     SUMMARY OF THE INVENTION 
     The present invention provides an apparatus for winding dynamoelectric machine field windings including a stator support for engaging and supporting a stator and a winding tool supported for reciprocating movement relative to the stator support. As the winding tool is reciprocated through a stator mounted on the stator support, wire is fed from a wire feed aperture in the side of the winding tool and into slots defined by radially inwardly extending teeth of the stator. 
     The winding tool is further supported for rotating or oscillating movement about a longitudinal axis of the winding tool. At each end of the reciprocating stroke of the winding tool, the winding tool is rotated to align the wire feed aperture with a different slot of the stator wherein the rotating movement of the winding tool corresponds to the formation of an end turn of the field winding or coil being formed within the stator. 
     A pair of wire holders or wire clamps are provided supported on the winding tool for reciprocating movement relative to the stator. A spring associated with each of the wire clamps biases each respective wire clamp toward the stator, and each wire clamp includes a surface extending substantially perpendicular to the longitudinal axis of the winding tool for engaging an end of the stator. 
     In operation, the wire clamps are alternately engaged with and disengaged from respective ends of the stator. In particular, as the winding tool is reciprocated to move the wire feed aperture along an internal slot of the stator core. and away from one end of the stator, a wire clamp is engaged with the end turns of field windings associated with the end of the stator from which the wire feed aperture is moving. The spring associated with the wire clamp permits the winding tool to move relative to the wire clamp while resiliently biasing the wire clamp against the end of the stator, and thus prevent radial inward movement of the wire as tension is applied to the wire. 
     Therefore, it is an object of the present invention to provide an apparatus for winding dynamoelectric machine field windings including providing a mechanism for engaging an end portion of a stator in cyclical engagement in order to hold the end turns of field windings in place. 
     It is a further object of the invention to provide such an apparatus wherein the means for engaging the ends of the stator include wire clamps mounted for reciprocating movement with a winding tool for the apparatus. 
     It is yet another object of the invention to provide a pair of winding clamps for alternately engaging with and disengaging from respective ends of a stator to facilitate maintaining field windings in place. 
     Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a winding tool incorporating the wire winding clamp of the present invention; 
     FIG. 2 is an exploded perspective view of the wire winding clamp of the present invention; 
     FIG. 3 is a side elevation view in partial cross-section illustrating a lower wire clamp in engagement with a stator during upward movement of the winding tool; 
     FIG. 4 is a side elevation view in partial cross-section showing a position of the winding tool at which the upper wire clamp transitions into engagement with the stator during, downward movement of the winding tool; and 
     FIG. 5 is a side elevation view in partial cross-section showing, the winding tool at its lowermost position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring, to FIG. 1, the wire winding, clamp  10  of the present invention is shown in combination with a winding tool  12  to which the wire winding clamp  10  is mounted. The wire winding clamp  10  includes an upper or first wire clamp  14  and a lower or second wire clamp  16 , the first and second wire clamps  14 ,  16  including respective proximal facing surfaces  18 ,  20  positioned in facing relationship to each other for engagement with opposing ends of a stator  24 , as will be described further below. 
     Referring to FIG. 2, each of the first and second wire clamps  14 ,  16  is formed as an annular cylindrical member positioned in sliding engagement over the winding tool  12 , and adapted for longitudinal sliding movement parallel to the axis of the winding tool  12 . The first wire clamp  14  is illustrated with a plurality of contact pads  26 , and in particular is illustrated with three contact pads  26 , and the second wire clamp  16  is provided with a corresponding number of contact pads  28 . The contact pads  26  are paired with the contact pads  28  and extend axially from the respective facing surfaces  18 ,  20  of the wire clamps  14 ,  16 , and are preferably, formed of a resilient material such as rubber. The number of pairs of contact pads  26 ,  28  provided to the wire clamps  14 ,  16  is dependent on the number of wire coils being formed simultaneously wherein in the preferred embodiment, from one to three pairs of contact pads  26 ,  28  may be provided to facilitate winding operations which wind one, two or three coils onto a stator core  24 . However, it should be understood that any number of pairs of pads  26 ,  28  may be provided depending on the number of wire coils being simultaneously wound during a given winding, operation. 
     The contact pads  26 ,  28  are defined as circumferentially spaced discrete members whereby the pads  26 ,  28  may individually engage the end loops or end turns of different coils being formed during a winding operation. The resilient engagement between the pads  26 ,  28  and the wire of the coil end loops ensures that the coil wire is not damaged as a result of engagement with the pads  26 ,  28 . Further. the provision of individual or discrete pads  26 ,  28  permits the pads to individually accommodate minor height variations between the coil end loops being engaged during the winding operation. 
     The wire winding clamp  10  further includes first and second coil springs  30 ,  32  attached to respective distal ends  34 ,  36  of the first and second wire clamps  14 ,  16  by fasteners  38 ,  40  affixed to the wire clamps  14 ,  16 . Outer ends  42 ,  82  of the springs  30 ,  32  distal from the wire clamps  14 ,  16  are each affixed in stationary relationship relative to the winding tool  12 . In the preferred embodiment, the outer end  42  of the spring  30  is detachably connected to the winding tool  12  to permit quick release and removal of the first wire clamp  14  for installation and removal of a stator  24  in between winding operations. As best seen in FIG. 2, the outer end  42  of the first spring  30  is attached to a cap member  44  by a bolt  45 , and the cap member  44  is detachably mounted to the winding tool  12 . 
     In the illustrated embodiment, a tool extension  46  is mounted to the end of the winding tool  12  and is held in place by a set screw  48 . A pin or stud  50  is mounted in a central aperture  52  of the tool extension  46  and is held in place by a fastener  54 . The cap  44  is provided with an aperture  56  which receives the stud  50  when the cap  44  is positioned on the end of the winding tool  12 . The cap  44  is provided with a cap extension  58  including a groove  60  receiving a spring wire latch member  62 . The latch member  62  includes a first end  64  received in an aperture  66  of the cap  44 , and an axially outwardly extending handle portion  68  located at an opposite, second end of the latch member  62 . The latch member  62  extends around a pivot bearing  70  held in place on the cap member by a fastener  72  wherein the pivot bearing  70  biases a central portion  74  of the latch member  62  within the groove toward the aperture  56  for engagement with a groove  76  defined in the stud  50  to hold the cap  44  in place. Thus, actuation of the handle  68  to move the central portion of the latch member  62  radially outwardly will result in disengagement from the groove  76  and thereby permit removal of the cap member  44  and associated first spring  30  and first wire clamp  14  from the winding tool  12 . 
     In addition, a pin  78  is provided extending through the cap extension  58  and passing through the groove  60  to limit the radial outward movement of the latch member  62 . An additional pin  80  may also be provided in the winding tool extension  46  to engage a cooperating aperture in the cap  44  and thereby provide circumferential alignment of the cap  44  and associated wire clamp  14  on the winding tool  12 . 
     The outer end  82  of the second spring  32  is fastened to the winding tool  12  by means of a collar  84  which is clamped to the winding tool  12  by means of a tightening fastener  86 . In addition, the end  82  of the spring  32  is attached to the outside of the collar  84  by means of a fastener  88 . In operation of the second clamp  16 , it is generally not necessary to remove the second clamp  16  since the stator  24  will be mounted for winding by positioning over the opposing end of the winding tool  12 . Accordingly, a relatively permanent mounting, such as that provided by collar  84  may be incorporated for positioning the outer end  82  of the spring  32 . 
     It should be apparent that the springs  30 ,  32  operate to bias the first and second wire clamps  14 ,  16  toward each other, and toward opposing faces of a stator  24  positioned therebetween. As will be described further below, movement of the winding tool  12  in a longitudinal direction will operate to alternately, or cyclically, position the wire clamps  14 ,  16  in engagement with the opposing faces of the stator  24  during a winding operation. Referring to FIGS. 3-5, a winding operation incorporating the wire clamp  10  of the present invention will now be described in greater detail. 
     The wire winding clamp  10  is designed to be incorporated into a winding machine  90  including a stator nest assembly having a platform  92  and a stator nest  94 . The stator nest  94  is adapted to detachably engage and support a stator  24  to be wound by the winding apparatus  90 . As illustrated in the present embodiment, the winding tool  12  extends upwardly through the platform  92  and is supported by a hollow spindle shaft  96  for driving the winding tool  12  in reciprocating and rotating or oscillating movement in a manner similar to that disclosed in U.S. Pat. No. 5,964,429, which patent is commonly assigned with the present application, and is incorporated herein by reference. 
     As described in the above noted patent, the spindle shaft  96  defines a wire passage which opens into a wire passage in the winding tool  12 , and extends to a wire feed aperture or apertures  98 . Wire W is fed through the apertures  98  at a predetermined controlled rate, and the winding tool  12  directs the wire W into slots of the stator  24  in a coil winding operation, as is more fully described in the above referenced U.S. Pat. No. 5,964,429. It should be noted that in the present embodiment, three wire feed apertures are disclosed for simultaneously feeding three wires W (only two shown) from the winding tool  12 , however, the present invention may be configured to accommodate a single wire aperture  98  feeding a single wire W, or alternatively may be configured to feed any number of a plurality of wires W wherein the wire clamps  14 ,  16  are provided with a number of pairs of contact pads  26 ,  28  corresponding to the number of wires W being fed from the winding tool  12 , and each of the contact pads  26 ,  28  including a contact surface extending substantially perpendicular to the longitudinal axis of the winding tool for engaging and holding in place the end turns of a wire coil being formed on the stator  24 . 
     As may be understood from the above referenced U.S. Pat. No. 5,964,429, the winding tool  12  is moved longitudinally to feed wire W from the apertures  98  and into slots defined in the stator  24 . At the end of its longitudinal movement, either upwardly or downwardly, the winding tool  12  is rotated to align the wire apertures  98  with different slots in the stator  24  and the winding tool  12  is moved longitudinally in an opposite direction from the previous longitudinal movement to again feed wire W through slots in the stator  24 . During the rotating movement of the winding tool  20 , a loop or end turn of the wire W is formed extending from the first slot to the second slot across the end of the stator  24 . As seen in FIG. 3, the winding tool  12  has reached an upper end of its longitudinal stroke wherein the lower or second wire clamp  16  is positioned in engagement with the lower end of the stator  24 , and the compression spring  32  has compressed to accommodate upward movement of the winding tool  12  relative to the second wire clamp  16  and thereby maintain a clamping force on the lower end turns of the wire coils being formed as the winding tool  12  moves upwardly. 
     After the winding tool  12  has rotated to align each of the wire apertures  98  with a further or a second slot, the winding tool  12  begins a downward longitudinal movement, carrying the upper or first wile holder  14  toward engagement with the upper end of the stator  24 . FIG. 4 illustrates the position of the wire winding clamp  10  after engagement of the first wire clamp  14  with the upper end of the stator  24 , and as the wire apertures  98  are moving downwardly between the ends of the stator  24 . It can be seen that both of the wire clamps  14 ,  16  are positioned in engagement with the opposing ends of the stator  24  during this portion of movement of the winding tool  12 . It can also be seen that the first wire clamp  14  will hold the upper end turns of the wire coils in place against any movement in response to tension applied to the wires W as they are pulled downwardly and inserted in the slots. 
     FIG. 5 illustrates the lowermost position of the winding tool  12  wherein the upper or first wire holder  14  is engaged with the upper end of the stator  24 , and the lower or second wire holder  16  is disengaged from the stator  24  for permitting rotation of the winding tool  12  to form a loop in the wire W across the lower end of the stator  24  prior to upward movement of the winding tool  12  to insert wire into the initial or first slot during upward movement of the winding tool  12 . In the position illustrated in FIG. 5, it can be seen that the first spring  30  has been compressed permitting the downward movement of the winding spindle  12  while maintaining a pressure on the upper end turns of the wire coils. 
     In addition, it should be noted that in the transition between the position shown in FIG.  4  and the position shown in FIG. 5, the second wire clamp  16  remains in engagement with the lower end of the stator  24  until just before the wire apertures  98  pass below the lower end of the stator  24 . Similarly, the first wire clamp  14  will remain in contact with the upper surface of the stator  24  until just before the wire apertures  98  pass above the stator  24  during upward movement of the winding tool  12 . 
     Thus, it should be apparent from the above description that the wire clamps  14 ,  16  are supported on the winding tool  12  for cyclically engaging opposing ends of the stator  24  in an alternating manner to clamp the wire coil windings being formed on the stator  24  without interfering with the efficient operation of the winding, tool as it distributes wire into the slots of the stator  24 . In particulars the wire clamps  14 ,  16  are supported for movement with the winding tool  12  while also permitting relative movement between the winding tool  12  and the wire clamps  14 ,  16  when either of the wire clamps  14 ,  16  is engaged with an end of the stator  24 . Further, the present winding wire clamp  10  provides means for quickly installing and removing a stator to and from a winding machine. Specifically, the present invention provides a quick release cap structure for removal of the upper or first wire clamp  14  to facilitate placement of a stator in the stator nest  94 . 
     Also, the design of the contact pads  26 ,  28  on the wire clamps  14 ,  16  is such that the contact pads do not extend the entire circumference of the stator, and provide spaced, discrete pads for localized contact with the end turns of the wire coils being formed. In this manner, contact pressure on the wire coil end turns is assured to ensure that the wire end turns are not permitted to move during the winding operation. 
     While the form of apparatus herein described constitutes a preferred embodiment of this invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.