Abstract:
A rotating electrical machine such as electrical starter motor and more particularly to an improved method and apparatus for winding the armature coils of a rotating electrical machine. The winding apparatus and method is particularly adapted for use with large diameter wires and permits winding without a winding needle having to pass into the slot between the pole teeth. This is accomplished by introducing some slack in the wire by moving the wire in a circumferential direction when the winding needle is not disposed in proximity to the slot and then returning the winding needle to registry with the slot.

Description:
BACKGROUND OF INVENTION 
     This invention relates to rotary electrical machines and more particularly to an improved winding method and apparatus for the armature coils for such machines. 
     Rotating electrical machines have been proposed for many applications. For example they may be used as a starter motor for an internal combustion engine. In such an application, a DC electric motor is powered from a battery for starting the engine. The starter motor generally comprises a stator comprising a cylindrical yoke with a plurality of magnets circumferentially bonded to an inner surface of the yoke. An armature (rotor) having coils arranged opposite the magnets and supplied with electrical current for driving a rotating shaft of the armature forming a output shaft of the starter motor. The motor output shaft drives a crankshaft of the engine via a reduction gear, an overrunning clutch for starting the engine in a well known manner. 
     The magnets may be ordinary magnets obtained by magnetizing a ferrite type magnetic material. The coils are formed by winding a wire (in general, a thin wire having a diameter of 0.9 mm or less) on each of a plurality of radially arrayed magnetic pole teeth of the armature. These pole teeth have a general T-shape. At this time, the core pole teeth are covered with insulators around which the wire is wound. 
     However, if this thick wire is used in a conventional winding device, tension in winding becomes larger because of the wire thickness. As a result the wound wire does not slide smoothly along the guide plate and fails to enter the slots easily. Also the curvature of the wire during winding becomes larger to prevent smooth winding. 
     However, if the nozzle is simply moved on the outside of the slots along rectangular magnetic teeth in a looping fashion, the thick wire with a large curvature interferes with edges of the magnetic pole teeth. This prevents smooth winding because the wire is stretched around the coil end portions with a large pressing force and reaction from the curvature of the thick wire results in a high tension. Thus, the wound wire is not allowed to freely move into the entrances from the coil end portions, preventing formation of stable and uniform coils. 
     SUMMARY OF INVENTION 
     A first feature of this invention is adapted to be embodied in a winding method for an armature for rotary electric machines having a core with a plurality of radially extending magnetic pole teeth and wherein the pole teeth are circumferentially spaced to form with slots between adjacent magnetic pole teeth. The method comprising the steps of introducing a wire into a slot moving a strand of wire in a looping fashion around at least one magnetic pole teeth to form a coil continuously along the magnetic pole tooth nozzle on the outside circumferential side of the core. The looping comprising in succession an axial forward motion from one side face of the armature to the other side face of the armature when in registry with a first slot at one circumferential side of the pole tooth, a circumferential forward motion on the other side face of the of the armature to registry with a second slot, an axial return motion from the other side face of the armature to the one side face of the armature and a circumferential return motion to the first slot. In accordance with the invention, at least one of the circumferential motions extends past the registry with the respective slot and then back to registry therewith for introducing slack in the wire being wound. 
     Another feature of the invention is adapted to be embodied in a winding device for simultaneously winding a plurality of coils on the radially extending poles of an armature. The winding device comprises an annular needle ring having a shape complimentary to the armature. A plurality of needle openings pass radially through the needle ring for delivering a plurality of wires for winding around the pole teeth. A drive effects relative rotation and axial movement between the needle ring and an armature for looping the plurality of wires around the pole teeth. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a cross sectional view taken generally along the axis of rotation of an electrical starter motor constructed in accordance with the invention. 
     FIG. 2 is a cross sectional view taken along the line  2 — 2  of FIG.  1 . 
     FIG. 3 is a cross sectional view taken along the line  3 — 3  of FIG.  1  and shows the brush carrier arrangement of the motor. 
     FIG. 4 is a developed view the winding pattern for one of the coils. 
     FIG. 5 is an end elevational view showing the armature as shown in FIG. 2 with the winding apparatus disposed around it. 
     FIG. 6 is a view looking in the same direction as FIG. 5 but shows in more detail the winding apparatus. 
     FIG. 7 is a side elevational view of the apparatus as shown in FIG.  6 . 
     FIG. 8 is a partial enlarged top plan view showing the winding apparatus. 
     FIG. 9 is a cross sectional view taken through the portion of the mechanism shown in FIG.  8 . 
     FIG. 10 is a view, in part similar to FIG. 4, but shows the winding pattern. 
     FIG. 11 is a perspective view again showing the winding pattern. 
     FIGS. 12 ( 1 ),  12  ( 2 ) and  12  ( 3 ) show the positions of the winding apparatus at the steps shown as ( 1 ), ( 2 ) and ( 3 ) during the movement from the point A to the point B as shown in FIG.  11 . 
     FIGS. 12 ( 4 ),  12  ( 5 ) and  12  ( 6 ) show the positions of the winding apparatus during the movement from the point B to the point C and then to the point D indicated at the steps ( 4 ), ( 5 ) and ( 6 ) in FIG.  11 . 
     FIGS. 12 ( 7 ),  12  ( 8 ) and  12  ( 9 ) show the positions of the apparatus during the movement from the point D to the point E and then the point F shown by the steps ( 7 ), ( 8 ) and ( 9 ) in FIG.  11 . 
     FIGS. 12 ( 10 ),  12  ( 11 ) and  12  ( 12 ) show the positions of the apparatus when moving from the point A to the point D at the steps ( 10 ), ( 11 ) and ( 12 ) in FIG.  11 . 
     FIGS. 12 ( 13 ),  12  ( 14 ) and  12  ( 15 ) show the positions of the apparatus during the movement from the point D to the point C and then to the point F as shown in the steps ( 13 ), ( 14 ) and ( 15 ) in FIG.  11 . 
     FIGS. 13 through 23 are side elevations views with portions shown in cross section of the winding apparatus during the various steps of winding. 
    
    
     DETAILED DESCRIPTION 
     Referring now in detail to the drawings and initially to FIGS. 1 through 3, a starter motor for an internal combustion engine is indicated generally by the reference numeral  51 . The starter motor  51  is shown as an embodiment of the invention and although this specific application is illustrated, it should be readily apparent to those skilled in the art that the invention can be utilized with other types of rotating electrical machines. 
     The starter motor  51  is comprised of an outer housing assembly, indicated generally by the reference numeral  52 , which includes a cylindrical yoke portion, indicated generally by the reference numeral  53 . The yoke portion  53  is comprised of a cylindrical shell  54  on the inner surface of which are bonded a plurality of circumferentially spaced permanent magnets  55 . In the illustrated embodiment, there are four such permanent magnets  55  and they are arranged with alternating plurality in a circumferential direction. Preferably, these permanent magnets  55  are formed from a neodymium type material that provides a high energy permanent magnet. 
     The housing  52  is completed by means of a front end cap  56  and rear end cap  57  that are affixed in any suitable manner to the ends of the yoke shell  54  to define an enclosed space in which a rotor in the form of an armature, indicated generally by the reference numeral  58  is journal led. The rear end cap  57  is formed with a mounting bracket  59  so as to permit attachment to the body of the associated engine. 
     The rotor or armature  58  is comprised of an armature shaft  61 , the forward end of which carries a starter gear  62  for associated with the starter gear on the flywheel of the associated internal combustion engine. The end cap  57  has a projecting end in which an O-ring seal  63  is received so as to provide a good seal around the starter gear. This end of the armature shaft  61  is journaled in the end cap  57  by an anti-friction bearing  64 . An oil seal  65  is disposed immediately to the rear of the bearing  64 . In a like manner, the rear end of the armature shaft  61  is journaled in an anti-friction bearing  66  carried by the end cap  57 . 
     The armature  58  is comprised of a core, indicated generally by the reference numeral  67 , and which has a construction as best shown in FIG.  2 . This is comprised of a laminated core having a plurality of radially extending pole teeth  68  which have enlarged head portions  69 . These pole teeth  68  are circumferentially spaced from each other to define slots  71  therebetween. The enlarged head portions  69  leave a narrow mouth  72  therebetween opening into the slots  71 . 
     Although not shown in details in FIGS. 1 through 3, individual coil windings are formed around the pole teeth  68  in the manner to be described shortly. The ends of these windings are connected, in a manner also to be described shortly, to a commutator, indicated generally by the reference numeral  73  and specifically to the contact strips  74  thereof. 
     As best seen in FIG. 3, brushes  75  are carried by brush carriers  76  mounted on a commutator plate or brush holder  77 . These brushes  75  are urged into engagement with the commutator strips  74  by springs  78 . 
     The electrical current for energizing the windings is delivered through a terminal box  79  carried on the rear end cap  57 . The electrical current is supplied to the brushes  75  from terminals  81 . This electrical arrangement is of a type well known in the art and, for that reason; a detailed description of it is not believed to be necessary. Again, since the generally construction of the starter motor  51  is of the type well known in the art, its details of construction except for the except for the way in which the coil windings are formed may be of any type known in the art. 
     The method and apparatus by which the coil windings are formed will now be described. First, the method of winding a single coil will be described by reference to FIG.  4 . In forming the coils, a wire  80  is wound around each set of a given number (four in the illustrated example) of magnetic pole teeth  68  twice to form a coil having two turns. One coil for each set of the four magnetic pole teeth is formed successively by changing the starting point of winding in a tooth by tooth pattern. 
     To do this, a starting end of a wire  80  of each coil is secured to a commutator strip  74  of one of middle two magnetic pole teeth  68  among the four magnetic pole teeth, and the terminating end thereof to the next commutator strip  74 , as shown in FIG.  4 . This terminal commutator strip  74  constitutes a starting end of the next coil. Thus, the wire  80  is secured to a commutator strip  74  corresponding to a magnetic pole tooth  68  located centrally of the given number of magnetic pole teeth  68  around which is wound the wire  80 , therefore the coil is configured such that a wire  80  is led obliquely from the starting and terminating two commutator strips  74  for winding. This winding action of the wire  80  is repeated (or winding actions are performed simultaneously), and coils are formed successively with respect to all the commutator strips  74 , one for each set of four magnetic pole teeth  68 . 
     In this winding action, when a thick wire (1 mm. diameter or greater) is used, a nozzle supplying the wire makes two looping motions outside slots as shown in the figure to introduce a coil into the slots so as to form a coil around the magnetic pole teeth. In this invention, the same number of nozzles as the radial magnetic pole teeth  68  are provided, corresponding thereto, at the outside circumferential side of the core, and the same number of coils as the magnetic pole teeth are formed with respect to all the magnetic pole teeth  68  simultaneously from the outside circumferential side of the core  67 . 
     FIG. 5 is a schematic view of a winding device for carrying out the foregoing simultaneous winding according to this invention, with a rotor set thereon. As has been noted, slots  71  are formed between radial magnetic pole teeth  68  armature  67 . A nozzle ring  82  is mounted in surrounding relation to the armature  67 . The nozzle ring  82  is provided with a number of nozzles  83  corresponding in number to the slots  71  (fourteen in this figure), that is, as many nozzles  83  as there are slots  71 . 
     Each nozzle  83  extends radially through the nozzle ring  82 . The inside circumferential side end of the nozzle  83  constitutes an outlet of for the wire  80  is chamfered or rounded at the corner for protection of the insulating coating of the wire. The wire supplied from the nozzle  83  and inserted into a slot  71  through the respective slot entrance  72 . 
     Then, one or both of the nozzle ring  82  and the core  67  is rotated and moved axially, causing each nozzle  83  to make a looping motion relative to the magnetic pole teeth  68 , so that the wire is wound around the magnetic pole teeth  68  to form a coil. This motion will be described in more detail later by reference to FIGS. 10 and 11. 
     As shown in FIGS. 6 and 7, in this example the nozzle ring  82  is provided with twenty-one nozzles  83  each corresponding to the respective twenty-one slots  71  of the armature  67 . The nozzle hole  83  passing radially through the nozzle ring  82 , has a large diameter portion at the outer circumferential side, which constitutes a guide hole  84  (FIG.  6 ). The guide hole  84  serves as a guide for a wire to be inserted, and has a large diameter for easy insertion. A wire  80  of a given length corresponding to the length of one coil is passed through the guide hole  84  and inserted into the corresponding slot  71 . 
     Referring now to FIGS. 8 and 9, the nozzle ring  82  is mounted on a rotatable turntable  85 . A pipe  86  is provided on the turntable  85  at the outside of each nozzle hole  83 . Each pipe  86  is formed, at its radially outer end, with a cutout  87  on the upper side. A stopper  88  pivotally mounted on a shaft  89  at each of the cutouts  87 . The stopper  88  serves as a means of preventing the wire inserted in the pipe  86  from slipping out. 
     The armature  58  is positioned centrally of the nozzle ring  82 . The wire passes through the pipe  86  to be supplied from the nozzle  83  in the nozzle ring  82  into a slot  71  of the armature  58 . Over and under the turntable  85  are provided blade-driving cylinders  91  for use in wire winding to be described later. 
     The winding pattern and method will now be described by reference to FIGS. 10 and 11. As shown in these figures, when wire winding action is performed on four magnetic pole teeth  68 , a nozzle opening  83  makes a looping motion through the path indicated at A→B→C→D→E→F→A. That is, the nozzle moves along one slot entrance  72  from position A to position B beyond one core tooth  68 , and then circumferentially to position C beyond the slot entrance  72  at the end of the core tooth group being wound. Then is returned at D to this end slot entrance  72 . 
     Then, the nozzle  83  returns along the coil slot entrance  72  to position E beyond the other coil slot entrance  72 . Then the nozzle  83  moves circumferentially to the position F beyond the initial slot entrance  72 . It then returns along the coil end to the position A. This motion is repeated and a wire is wound around the magnetic pole teeth  68  to form a further coil. 
     The actual positioning of the nozzle ring  82  and the armature  58  during this operation is shown in more detail in FIG. 12 ( 1 ) through FIG. 12 ( 15 ), these figure numbers correspond to the marked points in FIG.  11 . In these figures, only a single nozzle opening  83  is illustrated, but it should be readily apparent that each of the nozzle openings  83  is functioning in the same manner simultaneously during this winding operation. 
     These motions are described by reference to the various sub-figures of FIG. 12 as follows: 
     FIG.  12 ( 1 ) The end of the wire  80  is clamped with a clamping mechanism (not shown) and pulled out from a nozzle opening  83 . 
     FIG.  12 ( 2 ) The nozzle ring  82  with the wire  80  clamped is raised as shown by arrow a. 
     FIG.  12 ( 3 ) Raising of the nozzle ring  82  is paused for a moment and the rotor shaft  61  is rotated in the direction of arrow b with the end of the wire  80  being held, to offset the end of the wire  80  circumferentially. With the end of the wire offset, the end of the wire  80  is pushed into a groove (not shown) of a wire holding section  92  of the commutator  73  by the blade driving cylinder  91 . Thus, the slot entrance corresponding to the contact strip  74  of the starting end of the coil is offset circumferentially, as illustrated in FIG.  4 . 
     FIG.  12 ( 4 ) The nozzle ring  82  is then raised to point B of FIG. 11 beyond a coil end portion. 
     FIG.  12 ( 5 ) While the nozzle ring  82  is lowered in the direction of arrow c the rotor shaft  61  is rotated in the direction of arrow d, to move the nozzle ring  82  to point C of FIG. 11 where there is a circumferential overrun. 
     FIG.  12 ( 6 ) The rotor shaft  61  is rotated in the direction opposite to that in the step shown in FIG.  12 ( 5 ) (direction of the arrow e), and thus move the nozzle from point C of FIG. 11 to point D corresponding to the next entrance to a slot  71 . 
     FIG.  12 ( 7 ) The nozzle ring  82  is lowered in the direction indicated by the arrow f to move it to point E of FIG. 11 where it is overrun below the coil end portion. 
     FIG.  12 ( 8 ) The nozzle ring  82  is raised in the direction shown by the arrow g so as to return it by the downward overrun, the rotor shaft  61  is rotated in the direction of arrow h to move the nozzle opening  83  to point F of FIG. 11 where it is overrun circumferentially from the initial slot position. 
     FIG.  12 ( 9 ) The rotor shaft  61  is rotated in the direction of arrow i, to return the nozzle opening  83  from point F to point A of FIG.  11 . Thus, coil winding action for the first turn is completed. 
     FIG.  12 ( 10 ) The nozzle ring  82  is raised in the direction of arrow j to start the winding action for the second turn. This moves the nozzle opening  83  to point B where it is overrun upwardly, as in the step shown in FIG.  12 ( 4 ). 
     FIG.  12 ( 11 ) While lowering the nozzle ring  82  in the direction of arrow k so as to return it by the overrun, the rotor shaft  61  is rotated in the direction of arrow l, to move the nozzle opening  83  to point C where it is overrun circumferentially, as in the step shown in FIG.  12 ( 5 ). 
     FIG.  12 ( 12 ) The rotor shaft  61  is rotated in the direction of arrow m so as to return the nozzle by the overrun, move the nozzle to point D, as in the step shown in FIG. 12 ( 6 ). 
     FIG.  12 ( 13 ) The nozzle ring  82  is lowered in the direction of the arrow n, and moved to point E where it is overrun downwardly, as in the step shown in FIG.  12 ( 7 ). 
     FIG.  12 ( 14 ) The nozzle ring  82  is lowered further so that the terminating end of the wire  80  of a given length (length for two turns in this example) comes out from the nozzle opening  83 . 
     FIG.  12 ( 15 ) The terminating end of the wire is pushed by one of the blade driving cylinder  91  into a groove (not shown) of the wire holding section  92  of the commutator  73  to be held. The groove for the terminating end of the wire  80  is a groove adjacent to that for the starting end of the wire. 
     Then, the end portions of the wire protruded downwardly from the wire holding section  92  are trimmed and the starting and terminating ends of the wire are more positively affixed to the wire holding section  92  by hot caulking. 
     Thus, one coil of two turns is formed over, for example, four magnetic pole teeth (FIG.  10 ). Such coiling action is performed with respect to all the magnetic pole teeth using the foregoing nozzle ring  82  (FIG.  5  and FIG. 6) simultaneously, and all coils are formed simultaneously in one coil forming process. 
     FIGS. 13-23 are more detailed schematic views showing the apparatus and method, in step by step order during the procedure of winding according to this invention. 
     As shown in FIG. 13, an armature  58  held by a holder  93  such as a carrier robot hand is carried above a winding device  94 , and the upper part of the rotor shaft  61  is gripped with a chuck  95  on the winding device. The winding device  94  has a clamp  96  for holding the armature  58 , an upper movable blade  97 , the nozzle ring  32  below the upper movable blade  97 , a fixed blade  98  and a lower movable blade  99  below the nozzle ring  82 . 
     The clamp  96  is movable vertically with respect to a pedestal  101  for mounting the armature  58 . On the pedestal  101  are provided pairs of guide blades  102  corresponding radially to the slot entrances  72  of the armature  58 , one pair for each entrance. 
     The upper movable blade  97  enters a gap between blades of the guide blade  102 , and pushes a wire  80  into the slot  71 . To this end, the wire  80  is passed through the nozzle opening  83 , and the tip end of the wire is brought into contact with or close to the clamp  96 . At this time, the wire  80  passes through a pair of blades of the guide blade  102  as seen in FIG.  13 . 
     Then, as shown in FIG. 14, the armature  58  released from the holder  93  (FIG.  13 ), gripped by the chuck  95 , is lowered and placed on the pedestal  101 . Then, the clamp  96  is lowered in the direction of arrow p to clamp the end of the wire  80 . 
     Then, as shown in FIG. 15, the armature  58  is lowered (or the movable blades  99 ,  97 , fixed blade  98 , and nozzle opening  83  are raised) to start the upward stroke of the wire  80 . The wire  80  is raised while placed between the blades of the guide blade  102 . 
     Then, as shown in FIG. 16, clamping of the end of the wire  80  by the clamp  96  is released in the middle of the upward stroke of the wire  80  and the upward stroke is stopped for a moment. Then, the guide blade  102  is rotated in the direction of arrow q with respect to the armature  58  to twist the starting end of the wire  80  (this motion corresponds to the step of FIG.  12 ( 3 ). With the wire  80  twisted slightly, the lower movable blade  99  is moved in the direction of arrow r, and the starting end of the wire  80  is pushed into a groove (not shown) of the wire holding section  92  of the commutator  73  through a gap between the guide blades  102 . 
     Then, as shown in FIG. 17, the nozzle opening  83  is raised (or the armature  58  lowered) and the wire  80  is stretched. 
     FIG. 18 is a view showing an armature  58  on which a wire  80  is wound around magnetic pole teeth  68  by a given number of repeated winding action of looping motions overrunning axially and circumferentially as shown in FIG.  10  and FIG.  11 . 
     After completion of the winding action, the armature  58  is removed from the device and held again with a holder  93  (FIG. 13) to be transferred as shown in FIG. 19 to another winding device  103 . There a positioning blade  104  moves in the direction of arrow s and enters a slot entrance  72  (not shown) of the core, for positioning in the rotational direction. 
     Then, as shown in FIG. 20, a movable blade  105  consisting of a pair of blades, advances in the direction of arrow t to a position near the wire holding section  92  of the commutator  73  with the terminating end of the wire  80  held between its blades. 
     Then, as shown in FIG. 21, the armature  58  is rotated in the direction of arrow u, and the terminating end of the wire  80  is twisted circumferentially. The object of this process is to offset the terminating end of the wire for connection to the contact strip  74 , as shown in FIG.  4 . As a result, the terminating end of the wire  80  faces a groove (not shown) of the wire holding section adjacent to that for the starting end of the wire. 
     Then, as shown in FIG. 22, a pushing blade  106  advances in the direction of arrow v through a gap between the movable blades  105 , and pushes the terminating end of the wire  80  into the groove (not shown) of the wire holding section  92  of the commutator  73 . 
     Then, as shown in FIG. 23, the armature  58  is lowered to a position near a cutter  107  disposed downwardly of the winding device  103 . The cutter  107  is advanced in the direction of arrow w, and the wire ends protruding downwardly from the wire holding section  92  is trimmed. 
     According to this invention as described above, in one looping motion of the nozzle, the nozzle overruns a coil end portion, for example, at an axial upward stroke end; it moves, for example, circumferentially while returning by the overrun; it overruns a given position or a slot entrance, at the circumferential stroke end; and it transfers to an axial downward stroke after having returned by the circumferential overrun. Thus, the nozzle is overrun at the axial and circumferential stroke ends and makes subsequent stroke motions while returning or after having returned by the overrun, so that allowance in wire length is produced and smooth winding action is effected when coil winding on the magnetic pole teeth is performed without inserting a nozzle in a slot and by inserting only a wire in the slot. In particular, since circumferential overrun of the nozzle is returned, a tension exerted on the wire at core edges during winding of the coil ends is released, which prevents uneven height of the coil ends or irregular winding due to variation in tension, effecting formation of stable and uniform coil ends. Of course, the foregoing description is that of preferred embodiments of the invention and various changes and modifications may be made without departing from the spirit and scope of the invention, as defined by the appended claims.