Abstract:
A winding device for producing a field coil including a double-layer multiple-circuit winding for an electric motor includes a drive. The drive is configured to operate upon a winding mandrel with multiple lamellas arranged to be swung radially outwardly and inwardly by the drive in order to produce the double-layer multiple-circuit winding as a plurality of winding stacks that are arranged in separate slots and electrically connected in series, in parallel or both. At least two axially-separated winding stacks can be produced at the same time by the drive.

Description:
SUMMARY OF THE INVENTION 
     The present invention is based on a winding device for a field coil, processing equipment, and an electric. 
     In the production of three-phase machines such as motors or generators, the problem arises that, in order to attain uniform coil positioning and, therefore, maximum efficiency, the three phase coils of the stator winding must be inserted individually and in succession in the slots of the stator iron core such that they overlap in the manner of roof shingles. The known method, i.e., wind a phase angle for each pole, distribute its conductive wire in a continual manner, form a wire crossover with the second conductive wire and wind its phase coil, then repeat the entire procedure for the third phase coil, is not economical for series production. Plug-in windings, in the case of which individual conductor loops are connected after they are inserted into slots, are not an option when larger numbers of conductors and/or poles are involved, because too many connection points for electrical contacts result. Winding techniques in which winding is carried out separately and the individual phases designed as winding stacks are subsequently joined have disadvantages—due to the non-uniformity of the winding and the nearly unavoidable conductor crossovers—that affect the output, efficiency, and service life of the machine. 
     SUMMARY OF THE INVENTION 
     The present invention is based on a winding device for producing a field coil for an electric machine, particularly a field coil, with a double-layer multiple-circuit winding, in the case of which the field coil is formed by a plurality of winding stacks that are connected in series and/or in parallel. 
     According to the present invention, a winding mandrel is provided, on which at least two axially separated winding stacks can be produced simultaneously. 
     The present invention makes it possible to simultaneously—quasi-continually, in particular—produce a three-phase field coil using a continuous method, thereby making it economical to use in series production. Any number of poles and conductors is possible, and the distribution of conductors in individual winding stacks can be symmetrical or asymmetrical. It is therefore possible to produce a wide variety of different field coils, e.g., for an entire family of motors or generators. 
     In a favorable embodiment, the winding mandrel includes laminations that can be swung radially outwardly, and one winding stack can be fit in a slot between two laminations. With the laminations swung outward, the winding stack being wound currently is fixed in position axially on the winding mandrel. When the laminations are swung back into place, the winding stacks can be displaced axially along the longitudinal axis of the winding mandrel. 
     In a favorable embodiment, a wire feed unit is provided such that wires fed to the winding mandrel can be swiveled around at least two axes. The wire feed unit is preferably displaceable perpendicularly to the longitudinal axis of the winding mandrel. The wire feed can therefore be angled, displaced and transposed such that winding stacks or groups of winding stacks can be wound in different directions of rotation. Initially, a winding stack or a group of winding stacks can be wound in a first direction of rotation, then a winding stack or a group of winding stacks can be wound in the opposite direction of rotation. The two, opposing directions of rotation in which the winding stacks are wound result in a north pole and a south pole, respectively, when current is applied to the field coil. 
     In a favorable embodiment, the wire feed unit is movable perpendicularly to a longitudinal axis of the winding mandrel. The wire feed unit and winding mandrel are located in a fixed axial arrangement. Advantageously, fully wound winding stacks are moved out of this region, to create space for new winding stacks, while the wire feed unit and winding mandrel remain in their positions. The design and operation of the winding device are simplified, and fewer mechanically moved parts are required. 
     In a favorable embodiment, a fixing device for fixing the wires in position is movably located on the winding mandrel. To start winding a new winding stack, a particular wire can be reliably retained on the winding mandrel until it comes back to rest where it started, thereby securing itself against slipping. It is therefore possible to wind the wire reliably and securely. 
     In a favorable embodiment, the wound winding stacks are axially displaceable in order to wind further winding stacks. The winding stacks can be wound simultaneously in groups and removed from the winding area in order to create space for the next group of winding stacks. In this manner, any number of winding stacks or groups of winding stacks can be produced in a quasi-continual manner. Favorably, an advancing device for gripping and axially displacing the winding stacks is provided. It is advantageous that the winding stacks remain in their positions relative to each other and in the formation in which they are produced. The winding stacks can be produced at precisely defined spacial intervals and in dimensions as will be subsequently required in the field coil. 
     In a favorable embodiment, a guide device that is radially distanced from the winding mandrel is provided in order to fix the wires in position when the winding stacks are displaced axially. Advantageously, a retaining device is provided to secure the wires leading to the winding stacks when they are displaced axially, preferably in the form of bars that are oriented perpendicularly to the wires. The wires can therefore be fixed in an exactly defined position on one side of the winding mandrel, and/or they can be redirected, and the wire feed device can be moved from one side of the winding mandrel to the other side, in order to create a defined winding start for a winding stack or a group of winding stacks that is wound in the opposite direction. It is particularly favorable that the guide device can be operatively connected with the wire feed such that the wires can trade places. When wires are guided in parallel, in particular, at least two outer wires can trade places, while an inner wire remains in its position. A phase reversal of the wires can thereby be attained in an automated manner by changing the withdrawal plane by 180° using the wire feed, which can move along two axes. A position of the winding stacks with the correct phase can therefore be attained, since the three-phase coils are produced with alternating left and right directions of rotation. 
     A resultant loop of the wires from one group of winding stacks to the next can be inserted by a bending device into a slot between the laminations, thereby enabling winding to be carried out on top of the loops when the next group of winding stacks is wound. A loop bending device of this type is advantageously provided on each side of the winding mandrel. The quasi-endless loop formation with phase reversal makes it possible to produce any number of groups in an automated manner, with simultaneous production of winding stacks. 
     In a favorable embodiment, the guide device and the advancing device are located on the same feed carriage. The fact that one feed carriage is used ensures that the bending and transposition of the winding wires can be carried out in exactly defined dimensions relative to the winding mandrel and the axial displacement. 
     In a favorable embodiment, the length of the winding mandrel corresponds to a complete field coil and a single leading winding and a single lagging winding for each pole. In the stretched state, the single winding can be guided out of the field coil and used as a lead. Between the two single windings, the winding stacks of a first field coil can be separated from winding stacks of the next field coil. The field coil preferably includes three phase coils—with two poles each—located in individual winding stacks. The field coil can be used in a three-phase machine. 
     With inventive processing equipment with an inventive winding device, a transposition tool is provided, into which the winding stacks can be inserted in the order required per the winding mandrel. The distances between the winding stacks and their spacial arrangement are retained. The winding stacks can be tilted in a defined manner such that they overlap in the manner of roof shingles. In this configuration, the field coil can be joined, e.g., in corresponding slots of a flat laminated core, which is then bent in a round shape to form a hollow cylindrical stator. 
     The winding and transposition of the field coil can be applied in series production, and they make it possible to produce large quantities of identical field coils without an excessive amount of manual intervention. 
     With an inventive electrical machine, a field coil is provided that is produced using an inventive winding device described above. 
    
    
     
       DESCRIPTION OF THE DRAWING FIGURES 
       Further embodiments, aspects and advantages of the present invention also result independently of their wording in the claims, without limitation to generality, from exemplary embodiments of the present invention presented below with reference to the drawing. 
         FIG. 1  shows a view of a preferred winding device in an exploded-type depiction; 
         FIG. 2  shows a field coil before and after winding stacks are transposed; 
         FIG. 3  shows winding stacks of a field coil with a displacement device; and 
         FIGS. 4   a - e  show the steps that winding wires go through when a north pole is wound (a), and upon crossover to a winding of a south pole, with transposed placement (b), when bent and transposed by 180° (c), when bent and transposed by 45° (d), and at the beginning of the process to wind the south pole (e). 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Detailed Description of the Exemplary Embodiment 
       FIG. 1  is an exploded-type depiction of a preferred winding device for producing a field coil  30  for an electrical machine.  FIG. 2  shows field coil  30  with enumerated winding stacks  31   a ,  32   a ,  33   a  through  31   j ,  32   j ,  33   j , which can be produced simultaneously. Windings stacks  31   a  . . .  31   j  result in a first phase coil  31 , winding stacks  32   a  . . .  32   j  result in a second phase coil  32 , and winding stacks  33   a  . . .  33   j  result in a third phase coil  33 .  FIGS. 4   a - 4   e  depict the wire guiding steps described below. 
     A winding mandrel  10  with a longitudinal axis x has a rectangular cross section that defines the dimensions of the winding stacks of field coil  30  to be produced. It is possible to produce at least two axially separated winding stacks  31   a ,  32   a ,  33   a  on winding mandrel  10  simultaneously. Winding mandrel  10  is provided with swingable, compartment-shaped laminations  11  on its edges, which can be actuated from the inside using not-shown shafts. Via their separating shape, laminations  11  convert the otherwise smooth surface of winding mandrel  10  into an annular slot stack with slots  12  between laminations  11 . For simplicity, only a few of these elements are labeled with reference numerals in the figure and serve as examples. In slots  12  formed in this manner, wires u, v, w of the phase coil wires are wound simultaneously, thereby forming a first group of three winding stacks  31   a ,  32   a ,  33   a  in each slot  12 . 
     This procedure is carried out in the clockwise direction, e.g., to wind a north pole N, then a south pole S is wound in the opposite direction. To accomplish this, winding mandrel  10  is rotatable from one side around its longitudinal axis x using a suitable servo drive, which is not described in greater detail. Servo drive  29  makes it possible to provide any number of windings in the group of simultaneously wound winding stacks  31   a ,  32   a ,  33   a . It is also possible to produce an asymmetrical number of conductors, by using a different number of windings and by rotating in one direction and then in the other direction. 
     Wires u, v, w are fed to winding mandrel  10  through nozzles  20 ,  21 ,  22  using a wire feed unit  18  designed as a triple wire nozzle. A shaded region  17  indicates the actual position of wire feed unit  18 , which, for simplicity, is shown some distance away from winding mandrel  10  and its actual position. Wire feed unit  18  and winding mandrel  10  are located in a fixed axial arrangement. In its actual position, wire feed unit  18  is located above the winding mandrel in the vicinity of a clamping device  13  that includes two triple wire clamps. 
     To wind in the clockwise direction, wire feed unit  18  is moved with a carriage  19  perpendicularly to longitudinal axis x of winding mandrel  10  into a position that is, e.g., to the left (in the figure) of winding mandrel  10 , and it is moved to the right-hand side in order to wind in the opposite direction. It is thereby ensured that, when the winding direction is switched, fed wires u, v, w are under tension. After the three winding stacks  31   a ,  32   a ,  33   a  are wound, e.g., in the clockwise direction, the three winding stacks  31   b ,  32   b ,  33   b  are wound in the counterclockwise direction. 
     Clamping device  13  is movably mounted on winding mandrel  10 ; it includes two triple wire clamps (only one is shown), which are offset by 180°. To start a three-fold parallel winding of three winding stacks  31   a ,  32   a ,  33   a , first triple wire clamp  27  securely holds wires u, v, w up to an angle of rotation of 180°, then it hands off to the second, not-shown triple wire clamp and releases wires u, v, w. The first winding is completed using the adjacent, second triple wire clamp. Wires u, v, w are then also released from the second triple wire clamp, and the desired number of further windings can be wound using the stiction of the first winding. 
     When three simultaneous winding stacks  31   a ,  32   a ,  33   a , i.e., a three-phase pole coil, are completed, the rotation of winding mandrel  10  is halted and, depending on the current position of wire feed unit  18 , i.e., to the left or right of winding mandrel  10 , a guide device  15  designed as a guide block is raised from a lowered position ( FIG. 4   a ). A similar guide device  15  is located on both sides of winding mandrel  10 . As a result, retaining devices and/or shaped blocks  15   a ,  15   b ,  15   c —which are offset in a stepped manner and are designed as guide pins—are positioned behind the three wires u, v, w. 
     Wire feed unit  18  is rotatable and swivels the plane formed by the three adjacent wires u, v, w by −45° around the z axis. Simultaneously, nozzles  20 ,  21 ,  22  are swiveled by −45° around the y axis. Wires u, v, w now stretch across a plane that lies on the spacial diagonal ( FIG. 4   b ). Retaining devices  15   a ,  15   b ,  15   c  are located in corresponding positions. Each of the retaining devices  15   a ,  15   b ,  15   c  therefore retains the wire assigned to it, i.e., wire U, v or w. 
     An advancing device  23  is now moved toward winding mandrel  10 . Advancing device  23  includes, e.g., an upper feed comb  24  and a lower feed comb  25  offset by 180° relative thereto. Feed combs  24 ,  25  serve to maintain the orientation of winding stacks  31   a ,  32   a ,  33   a  that have already been wound. When feed combs  24 ,  25  have assumed the same orientation as the coils, laminations  11  are swung back into winding mandrel  10 . Winding mandrel  10  then has a smooth surface. A feed carriage  26  can now be moved; it carries first guide device  15  and a second guide device  16 —for which there is also a corresponding, not-shown guide device on the other side of winding mandrel  10 . In the meantime, winding mandrel  10  and wire feed unit  18  remain in their positions. 
     The shift forward extends for the width of three winding stacks  31   a ,  32   a ,  33   a , i.e., three pole coils and their intermediate spaces created by laminations  11 . Wires u, v, w are redirected into the x direction by guide device  15  ( FIG. 4   c ). 
     After the forward motion, laminations  11  are swung out of winding mandrel  10 , and advancing device  23  is retracted. Field coil  30  is now shifted to the right in the x direction on winding mandrel  11 , along the distance equal to a pole coil “triplet” composed of winding stacks  31   a ,  32   a ,  33   a . Guide devices  15 ,  16 , which are also mounted on feed carriage  26 , are moved in a synchronous manner with the forward motion. While the forward motion is being carried out, wire feed unit  18  changes its orientation around the z axis from −45° to +45°, and around the y axis, also from −45° to +45°. In conjunction with the forward motion in the x direction, therefore, wires u, v, w change positions, i.e., wire u located at the front in the x direction while the north pole coil is being wound remains in this position when the south pole coil is wound. This is accomplished by the fact that wire v of the middle phase remains in its position, and the two outer wires u, w trade positions by crossing over each other ( FIG. 4   c ). At the end of the forward motion, second guide device  16  is raised—after wires u, v, w have passed its position in the pulling and forward-motion direction—then wires u, v, w change direction again, from the x direction to the y direction, by carriage  19  moving to the left ( FIG. 4   d ). 
     While carriage  19  moves with wire feed unit  18  over winding mandrel  10 , wire feed unit  18  and nozzles  20 ,  21 ,  22  are swiveled back to their neutral position, by +45° along the particular axis. Wires u, v, w, which extend flat across winding mandrel  10  in slots  12  formed via swung-out laminations  11 , are fixed in position once more with upper triple wire clamp of fixing device  13 . Both guide devices  15 ,  16  are subsequently lowered once more. 
     In summary, after the winding of one group of winding stacks  31   a ,  32   a ,  33   a  is completed, guide device  15  is raised, then the three wires u, v, w—which have been swiveled by 45° on the y axis—are moved past it. Finally, and simultaneously with the forward motion of winding stacks  31   a ,  32   a ,  33   a —which have already been wound—the three wires u, v, w are pulled out of wire feed unit  18  in the x direction. A phase reversal of the withdrawal plane of wires u, v, w by 180° takes place, brought about by wire feed unit  18 , which is movable along two axes. The middle wire v remains in its position, while wires u and v trade positions. After the forward motion and phase-reversal motion, guide device  16  is raised, and the same procedure as took place with guide device  15  is carried out in reverse sequence. This is the only way to attain an in-phase arrangement of winding stacks  31   a ,  32   a ,  33   a , because the three-phase coils are created in the left and right winding direction in an alternating manner. 
     Using a not-shown bending tool, the three U-shaped loops  39  are distributed on winding mandrel  10 —in the same axis of motion—from the first coil triplet to second coil triplet  31   a ,  32   a ,  33   a ,  31   b ,  32   b ,  33   b , and the conductors are switched in the y direction. The shape of loops  39  and/or outwardly-swung laminations  11  and/or the bending tool make it possible to carry out this procedure. The position that is thereby attained corresponds exactly—apart from the wire feed side and the opposite winding direction now required—to the situation that existed when the winding of the first three winding stacks  31   a ,  32   a ,  33   a  was started ( FIG. 4   e ). The winding and clamping of the coil, and all of the other details also remain the same, apart from the fact that the nozzles are swiveled in the opposite directions. The next winding stacks  31   b ,  32   b ,  33   b  are wound over loops  39 , which are already in place. 
     If the aim is to create asymmetric numbers of conductors, all that has to be done is to adjust the number of windings differently forward/backward. 
     During the actual winding procedure, feed carriage  26  is returned to its starting position. In this manner, an endless field coil  30  is created quasi-continually. 
     Since the aim is to produce field coils  30  with a defined number of poles without having to redraw wires u, v, w after a field coil  30  has been completed, a three-fold single winding is wound before the first winding stack or the first group of winding stacks  31   a ,  32   a ,  33   a , so that two single-fold windings situated one behind the other are located between two complete field coils  30 . Winding mandrel  10  is designed such that there is enough space in slots  12  formed by laminations  11  and provided by feed combs  24 ,  25  for a complete field coil  30  and three single-fold windings. This means that, e.g., for each 16-pole, three-phase field coil  30  and the three single-fold windings mentioned, the number of slots that must be provided is N=57 slots (N=16×3+3×3). 
     When a field coil  30  is created with the leading and lagging single-fold windings, wire loops  39  for the next single-fold winding have been created, and wires u, v, w have been fixed in position once more on winding mandrel using fixing device  13 , a not-shown transfer device—designed as a pair of transfer combs, e.g., similar to feed comb pair  24 ,  25  but lying parallel to the xy-plane—is moved into position. The wire bridges between the single-fold windings can now be cut using a not-shown cutting device. Laminations  11  are swung inwardly, and separated field coil  30  can be pulled off of the winding mandrel in the x direction. Laminations  11  are then swung outwardly once more, and the winding procedure can be continued. 
     Separated field coil  30  is inserted in a transposition tool, as indicated in  FIG. 2 , by guiding the upper and lower coil conductors into not-shown slots. The slots are closed using not-shown swivel seals, to ensure that the conductors remain in their positions. The transfer combs are then retracted. 
     The two leading and lagging single-fold windings are withdrawn from the coil core using a drawing device, and they form the subsequent connecting lines. The 16-pole, three-phase field coil  30  is now transposed into a skewed position, and the 48 individual coils now overlap each other in the manner of roof shingles (lower part of  FIG. 2 ). A double-layer multiple-circuit winding is therefore formed, which can be joined, e.g., in slots of a flat laminated core. The laminated core can then be bent round into the shape of a hollow cylinder to form a stator of a preferred electrical three-phase machine. 
       FIG. 3  shows winding stacks  31   a ,  32   a ,  33   a  . . .  31   e ,  32   e ,  33   e  of a field coil  30  wound in opposing winding directions in an alternating manner. This results in the formation of alternating north poles N and south poles S in field coil  30 . A section of a feed comb  25  is also shown; it is provided to displace winding stacks  31   a ,  32   a ,  33   a  . . .  31   e ,  32   e ,  33   e . Its teeth that face winding stacks  31   a ,  32   a ,  33   a  . . .  31   e ,  32   e ,  33   e  line up with the gaps between winding stacks  31   a ,  32   a ,  33   a  . . .  31   e ,  32   e ,  33   e . Toward the back of the figure, it is shown how wires u, v, w are already in place at the start of a procedure to wind winding stacks  31   f ,  32   f ,  33   f . Small arrows indicate the direction of rotation in which the particular group of winding stacks  31   a ,  32   a ,  33   a  . . .  31   e ,  32   e ,  33   e  have been wound. 
       FIGS. 4   a  through  4   e  illustrate how the wires are guided when field coil  30  and carriage  19  of wire feed unit  18  are displaced, as described above in conjunction with the procedure described with reference to  FIG. 1 .  FIGS. 4   b  through  4   e  only show the details of how the wires are guided.  FIG. 4   a  also shows a drive  40  for swinging laminations  11  outwardly and inwardly. Drive  40  is driven using not-shown gears and shafts at each edge of winding mandrel  11 . An output wheel  35  is non-rotatably connected with the winding mandrel and drives an axle  38  via driving means  36 , e.g., a chain or belt. Numeral  27  labels an element of one of the guide devices on the other side of winding mandrel  10  that functions in a manner analogous to that of guide devices  15 ,  16 . It is also connected in a driving manner via driving means  37  with a hollow cylinder  24  that rotates three-fold clamps  13   a  and  13   b  in a synchronous manner with winding mandrel  10 . A shaded region  41  near laminations  11  and slots  12  (only a few of the large number of similar elements are shown) indicates the actual position of three-fold wire clamps  13   a ,  13   b . Three-fold clamps  13   a ,  13   b  are located on the inner circumference of hollow cylinder  14  such that they are offset by 180°, and they extend axially beyond hollow cylinder  24  so far that hollow cylinder  14  does not collide with the wire feed.