Patent Publication Number: US-2023143083-A1

Title: Coil forming apparatus and coil forming method

Description:
This application is based on and claims the benefit of priority from Japanese Patent Application No. 2021-184359, filed on 11 Nov. 2021, the content of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a coil forming apparatus and a coil forming method. 
     Related Art 
     The stator of a rotary electric machine has a band-shaped coil in a wound state. The band-shaped coil is formed in advance in a substantially cylindrical wound state having a smaller diameter than the inside diameter of the stator core, and is inserted inside of the stator core. The band-shaped coil in the wound state is expanded in diameter inside of the stator coil, and is mounted by inserting the straight portion of the band-shaped coil into a slot of the stator core. 
     Conventionally, it has been known to mold the band-shaped coil into a wound state of substantially cylindrical shape by winding on a coil winding jig, while feeding by one pitch at a time on the columnar coil winding jig (for example, refer to Patent Document 1), 
     Patent Document 1: Japanese Patent No.4953032 
     SUMMARY OF THE INVENTION 
     When forming the coil into the wound state by winding the coil, it is important that a plurality of straight portions are wound accurately without displacing. In the above prior art, by inserting a preliminary alignment member between adjacent straight portions in a position immediately preceding the coil winding jig on the conveying path of the band-shaped coil, the superposition of the immediately preceding straight portion to be wound in the coil winding jig is aligned. 
     However, in the above prior art, there is no specific disclosure of how the coil winding jig is configured to wind the band-shaped coil, and the problem of the winding posture in the coil winding jig being disturbed by spring back of the band-shaped coil is not mentioned therein. If the winding posture of the band-shaped coil is disturbed, it will lead to poor quality. A decline in yield due to poor quality leads to material loss and an increase in electrical consumption due to lengthening the equipment operating time. 
     The present invention has been made taking account of the aforementioned such situation, and has an object of providing a coil forming apparatus and a coil forming method capable of easily forming a band-shaped coil in a wound state, without, the winding posture in the coil winding jig being disturbed by spring back of the band-shaped coil. In addition, it is consequently an object of reduce the adverse effects on the global environment, by decreasing the material resources and energy cost. 
     A coil forming apparatus (for example, the coil forming apparatus  1  as described later) according to a first aspect of the present invention forms a band-shaped coil (for example, the band-shaped coil  100  described later) in a wound state, the band-shaped coil including a plurality of straight portions (for example, the straight portions  102  described later) and side ends (for. example, the side ends  103  described later) provided on both ends of the plurality of straight portions, the coil forming apparatus including: a coil winding jig (for example, the coil winding jig  2  described later) that winds the band-shaped coil, the coil winding jig including a plurality of comb-shaped grooves (for example, the comb-shaped grooves  23  described later) on an outer periphery thereof, each of which can hold a respective one of the plurality of straight portions therein; a coil conveying mechanism (for example, the coil conveying mechanism unit  3  described later) that pivotally conveys the band-shaped coil along at least a portion of the outer periphery of the coil winding jig; and guide members (for example, the guide member  4  described later) that are provided in a vicinity of both ends of the coil winding jig in an axial direction, and guide the band-shaped coil In an arc shape to insert in a respective one of the plurality of comb-shaped grooves while being in contact with the side end, in which the guide members include a diameter-reducing guide part (for example, the diameter-reducing guide part  41   r  described later) provided to gradually reduce in diameter in a second half portion of pivot conveying of the band-shaped coil along a path of the pivot conveying, and an extension guide part (for example, the extension guide part  41   m  described later) which links to an end edge (for example, the end edge  4   b  described later) of the diameter-reducing guide part arid extends a predetermined length by maintaining a diameter according to curvature of the end edge. 
     According to a second aspect of the present invention, in the coil forming apparatus as described in the first aspect, the extension guide part may have an extension length capable of abutting at least a pair of the straight portions linking to the same side end of the band-shaped coil. 
     A coil forming method according to a third aspect of the present invention forms a band-shaped coil (for example, the band-shaped coil  100  described later) in a wound state, the band-shaped coil including a plurality of straight portions (for example, the straight portions  102  described later) and side ends (for example, the side ends  103  described later) provided on both ends of the plurality of straight portions, the method including: a coil conveying step of pivotally conveying the banc-shaped coil along at least a portion of an outer periphery of a coil winding jig (for example, the coil winding jig  2  described later), the coil winding jig including a plurality of comb-shaped grooves (for example, the comb-shaped grooves  23  described later) on an outer periphery thereof, each of which can hold a respective one of the plurality of straight portions therein, and being configured to wind the band-shaped coil, and a guiding step of providing guide members (for example, the guide member  4  described later) in a vicinity of both ends of the coil winding jig in an axial direction, guiding the band-shaped coil so as to be in an arc shape while bringing the guide member into contact with the side end so as to insert into a respective one of the plurality of comb-shaped grooves, in which the guiding step includes: a diameter-reducing guide step of guiding the band-shaped coil so as to gradually reduce in diameter at a second half portion of the pivot conveying along a path of the pivot conveying, and an extension guide step, immediately following the diameter-reducing guide step, of guiding the band-shaped coil to extend a predetermined length by maintaining a diameter according to a curvature immediately following the diameter-reducing guide step. 
     According to a fourth aspect of the present invention, in the coil forming method as described in the third aspect, the extension guide step may maintain guidance over, an extension length capable of abutting at least a pair of the straight portions linking to the same side end of the band-shaped coil. 
     According to the coil forming apparatus as described in the first aspect, the band-shaped coil is gradually reduced in diameter by the diameter-reducing guide part at the second half portion of pivot conveying, and spring back is suppressed by the extension guide part linking to the end edge, even when reaching the end edge of the diameter-reducing guide part. For this reason, the winding posture being distorted in the coil winding jig by spring back of the band-shaped coil is avoided. In addition, consequently, by reducing material loss causing a decline in yield due to poor quality and an increase in electrical energy consumption due to lengthening the equipment operating time, it is possible to reduce the adverse effects on the global environment. 
     According to the coil forming apparatus as described in the second aspect, the extension guide part has the extension length capable of abutting at least a pair of the straight portions linking to the same side end of the band-shaped coil; therefore, spring back of the band-shaped coil is effectively inhibited. 
     According to the coil forming method as described in the third aspect, the guiding step of guiding the band-shaped coil in an arc shape to insert into a respective one of the comb teeth-shaped grooves includes the diameter-reducing guide step and the extension guide step. In other words, immediately after the diameter-reducing guide step of guiding the band-shaped coil so as to gradually reduce in diameter, it advances to the extension guide step immediately following of guiding by maintaining the diameter from the curvature to extend the band-shaped coil by a predetermined length. Therefore, spring back of the band-shaped coil is suppressed. For this reason, in the band-shaped coil, the winding posture being disturbed by spring back thereof is avoided. 
     According to the coil forming method as described in the fourth aspect, since guidance is maintained over the extension length capable of abutting at least the pair of straight portions linking to the same side end of the band-shaped ceil, spring back of the band-shaped coil is effectively inhibited. 
     In addition, the coil forming apparatus as described in the first and second aspects, and the coil forming method as described in the third and fourth aspects are collectively premised on using material made into a series of band-shaped coils in advance, as the coils set in the stator. Upon setting the coil into the slot of the stator, the current mainstream technique is a technique which divides and forms the coil into a plurality of segments, and after inserting into the slots, welds the coil ends. In this general technique, it is necessary to use high purity copper in the coil so as to be able to withstand the thermal processing at the weld location. In contrast, since coping with the thermal processing is unnecessary with the present invention, it is possible to use recycled copper wire containing impurities, which can contribute to the realization of the recycling of resources. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a side view showing an embodiment of a coil forming apparatus of the present invention; 
         FIG.  2    is a drawing viewing the coil forming apparatus shown in  FIG.  1    from the A direction in  FIG.  1   ; 
         FIG.  3    is a drawing viewing the coil forming apparatus shown in  FIG.  1    from the B direction in  FIG.  1   ; 
         FIG.  4    is a perspective view showing an embodiment of a coil wincing jig; 
         FIG.  5    is a perspective view showing a piece member of a grip portion of a coil conveying mechanism unit; 
         FIG.  6    is a perspective view showing an aspect viewing the piece member of the grip portion of the coil conveying mechanism unit from the opposite side of  FIG.  5   ; 
         FIG.  7    is a perspective view showing a state connecting two piece members; 
         FIG.  8    is an enlarged view of a portion E in  FIG.  1   ; 
         FIG.  9    is an enlarged view of a portion C in  FIG.  1   ; 
         FIG.  10    is a cross-sectional view showing an aspect of the band-shaped coil being guided into an arc shape in the coil winding jig by a guide member; 
         FIG.  11    is an enlarged cross-sectional view of a portion D in  FIG.  1   ; 
         FIG.  12    is a partial enlarged view showing an aspect of the band-shaped coil being wound multiply on the coil winding jig; and 
         FIG.  13    is a perspective view showing a state in which the band-shaped coil is molded in a wound state on the coil winding jig. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, an embodiment of the present invention will be explained. As shown in  FIG.  1   , a coil forming apparatus  1  of the present embodiment includes: a coil winding jig  2 ; a coil conveying mechanism unit  3  which causes a hand-shaped coil  100  which is a so-called wave-winding band-shaped coil to convey along the outer circumference of the coil winding jig  2 ; and a pair of guide members A which guide the band-shaped coil  100  conveyed by the coil conveying mechanism unit  3  so as to be wound on the coil winding jig  2 . 
     Band-shaped Coil 
     As shown in  FIG.  3   , the band-shaped coil  100  is molded into an elongated corrugated band-shape by rectangular conductor wires  101  having a substantially rectangular cross-sectional shape. The rectangular conductor wires  101  are formed from a metal having high conductivity such as copper or aluminum, for example. 
     The band-shaped coil  100  has a plurality of straight portions  102  and a plurality of side ends  103 . The straight portions  102  are parts to be inserted in a slot provided in the inner circumference of a stator core which is not illustrated, and are arranged In parallel at a predetermined interval to extend substantially linearly in the same direction, respectively. The side ends  203  are respectively arranged at a position closer to the side end of the band-shaped coil  100  than the straight portion  102 , i.e. at both ends in the extending direction of the straight portion  102 . The side ends  103  couple adjacent straight portions  102  at one end portion and the other end portion alternately in a mountain shape, and constitute coil end parts, each projecting in an axial direction of the stator core from the stator, upon the band-shaped coil  100  being mounted to the stator of the stator core. 
     The band-shaped coil  100  of the present embodiment is provided in an elongated band shape by arranging six rectangular conductor wires  101  in a manner in which the plurality of straight portions  102  are provided in parallel to each other at a constant interval, and the plurality of side ends  103  are shifted by the pitch of the straight portions  102  to be stacked. The six rectangular conductor wires  101  are provided by folding the plurality of straight portions  102  and the plurality of side ends  103  respectively in a corrugated shape. The straight portions  102  of the band-shaped coil  100  are stacked in the thickness direction (the vertical direction relative to the paper plane of  FIG.  3   ) of the band-shaped coil  100  by folding back the rectangular conductor wire  101  in the middle. The band-shaped coil  100  of the present embodiment has a length that is wound four times around the coil winding jig  2  to be described later. 
     Coil Winding Jig 
     As shown in  FIG.  4   , the coil winding jig  2  includes: a substantially cylindrical jig main body  21 ; a plurality of comb teeth  22  protruding radially to the outer circumference of the jig main body  21 , a plurality of comb teeth-shaped grooves  23  provided between the adjacent comb teeth  22 ,  22  in the circumferential direction, and an axial hole  24  opened at the center of the jig main body  21 . The comb teeth  22  and comb teeth-shaped groove  22  are respectively provided at both ends in the axial direction of the jig main body  21 . The phases of the comb teeth  22  and comb teeth-shaped groove  23  at one end of the jig main body  21  and the comb teeth  22  and comb teeth-shaped groove  23  at the other end are aligned. The coil winding jig  2  of the present embodiment has  72  comb teeth-shaped grooves  23  respectively at both ends in the axial direction of the jig main body  21 . The number of these comb teeth-shaped grooves  23  matches the number of slots in the stator core in which the band-shaped coils  100  are mounted. 
     The interval distance between the comb teeth  22  and comb teeth-shaped groove  23  at one end of the jig main body  21  and the comb teeth  22  and comb teeth-shaped groove  23  at the other end is substantially equal to the length in the extending direction of the straight portion  102  of the band-shaped coil  100 . Therefore, the straight portion  102  of the band-shaped coil  100  can be accommodated over the comb-shaped groove  23  at one end and the comb-shaped groove  23  at the other end of the jig main body  21 . 
     The coil wincing jig  2  is formed so that the outside diameter of the coil winding jig  2  defined by the position of the leading end of the comb teeth  22  is no more than the inside diameter of the stator core, so that it becomes possible to insert inside of the stator core. The coil winding jig  2  is arranged at a predetermined site of the coil forming apparatus  1 , and is provided to be rotatable in the dl direction shown by the arrow in  FIG.  1   , centered around the axial hole  24  by driving of a motor which is not illustrated. 
     Coil Conveying Mechanism Unit 
     The coil conveying mechanism unit  3  pivotally conveys the band-shaped coil IOC along at least part of the outer circumference of the coil winding jig  2 . More specifically, the coil conveying mechanism unit  3  has a pair of conveying rails  31  constituting a conveying path of the band-shaped coil  100 , and a conveyor  32  which grips the band-shaped coil  100  and conveys along the conveying rails  31 , as shown in  FIGS.  1  and  2   . 
     The conveying rails  31  are formed in a band-shaped plate made of metal, and arranged in parallel to each other with substantially equal intervals to the length of the straight portion  102  of the band-shaped coil  100 , in the width direction of the coil forming apparatus  1 . The interval of the pair of conveying rails  31  is substantially equal to the interval distance in the axial direction of the comb teeth  22  and comb-shaped groove  23  of the coil winding jig  2 , as shewn in  FIG.  2   . 
     The conveying rails  31  includes a pair of upper and lower parallel linear conveying parts  311 ,  312  forming a linear conveying path, and a pivot conveying unit  313  which connects the ends or. the linear conveying parts  311 ,  312  in an arc shape, thereby forming a lateral U-shaped conveying path. The conveying rails  31  are provided so as to surround the coil winding jig  2  by arranging on the inner side of the U-shaped portion, so that the pivot conveying unit  313  follows the outer circumference of the coil winding jig  2 . As shown in  FIG.  2   , pairs of guide grooves  314  spanning the entire length of the conveying rail  31  are respectively provided to the faces on which the pair of conveying rails  31  are opposing each other. The guide groove  314  forms a travel path of a conveyor  32  described later. 
     In the present embodiment, the pivot conveying unit  313  of the coil conveying mechanism unit  3  is formed along a range approximately ½ of the outer circumference of the coil winding jig  2 . The pivot conveying unit  313  includes a first half portion  313   a  on the introducing side of the band-shaped coil  100  and a second half portion  313   b  on the discharging side of the band-shaped coil  100 . The first half portion  313   a  is formed over a range of approximately ½ the first half of the pivot conveying unit  313 . The second half portion  313   b  is provided over a range of approximately ½ the second half of the pivot conveying unit.  313 . However:, the pivot conveying unit  313  may be configured to be able to pivotally convey the band-shaped coil.  100  along at least a portion of the outer periphery of the coil winding jig  2 . 
     The conveyor  32  extends long along the conveying rail  31  and can move along the conveying rail  31  between the pair of conveying rails  31 . The conveyor  32  has a length corresponding to at least the total length of the band-shaped coil  100 , and moves along the conveying rail  31  in a state of holding the straight portions  102  of the band-shaped coil  100  on the upper surface, thereby pivotally conveying the band-shaped coil  100  along the outer periphery of the coil winding jig  2 . 
     As shown in  FIGS.  1  and  3   , the conveyor  32  includes a plurality of piece members  33  of the same structure arranged in a multilayer shape along the length direction of the band-shaped coil  100 . As shown in  FIGS.  5 ,  6  and  7   , the piece members  33  each include a piece member body  331  having a substantially rectangular plate-like shape made of metal, and a pair of guide projections  332 , each projecting laterally from both ends in the width direction at the lower end of the piece member body  331 . The guide projections  332  of the present embodiment each include a rotatable roller; however, they may be simple projections. In addition, regarding the directions of the piece member  33 , in  FIGS.  5 ,  6 , and  7   , the X direction is defined as the width direction, the Y direction is defined as the thickness direction, and the Z direction is defined as the height direction. In the height direction, the upper direction in the drawings is defined as “up”, and the lower direction is defined as “down”. 
     The piece member body  331  has a thickness substantially equal to the gap between adjacent straight portions  102  and  102  in the length direction of the band-shaped coil  100 . The piece member body  331  has an upper end surface  331   a,  and the upper end surface  331   a  includes a pair of first gripping claws  333 , each projecting in the height direction. The first gripping claw  333  has a thickness of approximately ½ the thickness of the piece member body  331 . The thickness of the first gripping claw  333  is substantially equal to the gap between the adjacent straight portions  102  and  102  of the band-shaped coil  100 . The first gripping claw  333  is provided at a position in the vicinity of one end in the thickness direction of the piece member body  331  on the upper end surface  331   a.  The pair of first gripping claws  333  are disposed apart from each other on both end sides in the width direction of the piece member body  331  with a predetermined interval therebetween. 
     The first gripping claws  333  each have an upper end surface, anti the upper end surface includes a meshing groove  333   a  that meshes with a tip of the comb tooth  22  of the coil winding jig  2 . More specifically, as shown in  FIG.  4   , the tip of the comb tooth  22  of the coil winding jig  2  has an engaging portion  22   a.  The meshing groove  333   a  has a position and a shape capable of meshing with the engaging portion  22   a  of the coil winding jig  2 . 
     The first gripping claws  333  each have a tapered surface  333   b  on the side opposite to the side on which the upper end surface  331   a  is provided. The tapered surface  333   b  allows the first gripping claw  333  to be formed in a slightly tapered shape as it moves away from the piece member body  331 . 
     The pair of first gripping claws  333  has a rectangular recess  334  along the height direction of the piece member body  331  provided therebetween. The recess  334  is provided to span from the upper end surface  331   a  to the portion approximately ½ the height of the piece member body  331 . The depth of the recess  334  along the thickness direction of the piece member body  331  has a depth of approximately ½ the thickness of the piece member body  331 , similarly to the first gripping claw  333 . 
     The piece member body  331  includes a rectangular protrusion  335  provided on one side surface  331   b.  The protrusion  335  is provided to protrude, in the thickness direction of the piece member body  331 , in a block shape toward a direction perpendicular to the side surface  331   b  from the side surface  331   b  which is opposite to the side where the first gripping claw  333  is provided. The protrusion  335  is provided above a site which is approximately ½ the height of the piece member body  331  in the height direction. The height of the protrusion  335  along the height direction of the piece member body  331  is substantially equal to the height of the recess  334 . The thickness of the protrusion  335  along the thickness direction of the piece member body  331  is substantially equal to the depth of the recess  334 . 
     The protrusion  335  includes a second gripping claw  336  provided at an upper end portion thereof. Similarly to the first gripping claws  333 , the second gripping claw  336  projects upward from the upper end surface  331   a  of the piece member body  331 . Similarly to the first gripping claws  333 , the thickness of the second gripping claw  336  is substantially equal to the gap between the adjacent straight: portions  102  and  102  of the band-shaped coil  100 . Since the second gripping claw  336  has the same width as the protrusion  335 , as shown in  FIG.  7   , when the two piece members  33  and  33  are stacked with their directions aligned with each other, the second gripping claw  336  of the one piece member  33  is disposed between the pair of first gripping claws  333  and  333  of the other piece member  33 . 
     The second gripping claw  336  has tapered surfaces  336   a  on both the side on which the upper end surface  331   a  is provided and the opposite side thereto. These tapered surfaces  336   a  allow the second gripping claw  336  to be formed in a slightly tapered shape as it moves away from the piece member body  331 . 
     As shown in  FIG.  7   , the plurality of piece members  33  are aligned such that the first gripping claws  333  and the second gripping claws  336  are oriented in the same direction, and the protrusions  335  of the piece member  33  are stacked so as to be accommodated in the recess  334  of the adjacent piece member  33 . As a result, the adjacent piece members  33  and  33  are in close contact with each other and stacked. 
     The piece member  33  includes a through hole  337   a  extending in the width direction of the piece member  33  at a portion in the vicinity of the root of the first gripping claw  333  and substantially at the same height as the upper end surface  331   a  of the piece member body  331 . In addition, the protrusion  335  includes a through hole  337   b  extending in the width direction of the protrusion  335  at a portion in the vicinity of the root of the second gripping claw  336  and substantially at the sane height as the upper end surface  331   a  of the piece member body  331 . As shown in  FIG.  7   , after the two piece members  33  and  33  are stacked, a shaft member  338  is inserted to span the through hole  337   a  arid the through hole  337   b  which are in communication with each other. Thus, with the shaft member  338  as a rotation axis, the lower end sides of the plurality of pieces members  33  where the guide projections  332  are provided are coupled with each other in a rotatable (swingable) manner in the length direction of the conveyor  32 , thereby forming an elongated conveyor  32 . 
     As shown in  FIGS.  3 ,  7 ,  8 , and  9   , in the conveyor  32 , gripping grooves  321  each gripping the straight portion  102  of the band-shaped coil  100  is provided between the first gripping claws  333  and  333 , and between the second gripping claws  336  and  336  of the adjacent piece members  33 ,  33 . The upper end surface  331   a  of the piece member body  331  is provided at the bottom of the gripping groove  321 . The gripping grooves  321  each have a groove width capable of accommodating the straight portion  102  of the band-shaped coil  100 . The groove width of the gripping groove  321  is substantially equal to the groove width along the circumferential direction of the comb-shaped groove  23  of the coil winding jig  2 . The arrangement pitch of the gripping grooves  321  along the length direction of the conveyor  32  is substantially equal to the arrangement pitch of the comb-shaped groove  23  along the circumferential direction of the coil winding jig  2 . Therefore, when the meshing groove  333   a  and the engaging portion  22   a  are engaged with each other, as shown in  FIG.  8   , the gripping groove  321  of the conveyor  32  and the comb-shaped groove  23  of the coil winding jig  2  are in communication with each other in the radial direction of the coil winding jig  2 . 
     In the conveyor  32 , each guide projection  332  of the piece member  33  is slidably accommodated in the guide groove  314  of the conveying rail  31 , and protrudes toward the inside of the U-shaped conveying rail  31 . Furthermore, as shown in  FIG.  8   , the meshing groove  333   a  of the piece member  33  meshes with the engaging portion  22   a  of the coil winding jig  2  at the location immediately below the coil winding jig  2 , such that the conveyor  32  is in synchronization with the rotation of the coil winding jig  2  by the rotation of the coil winding jig  2  in the direction d 1  so as to be movable in the direction d 2 . When the conveyor  32  moves in an arc shape along the pivot conveying unit  313  of the conveying rail  31 , the guide projections  332  of the piece members  33  and  33  adjacent to each other rotate by means of the shaft member  338  so as to be isolated with the portions of the first gripping claw  333  and the second gripping claw  336  which are sites for gripping the straight portions  102  as references, such that the conveyor  32  is smoothly movable. 
     As shown in  FIGS.  3 ,  8 , and  9   , in the conveyor  32  which is slidably disposed on the conveying rail  31 , the first gripping claw  333  and the second gripping claw  336  are inserted into the gap between the straight portions  102  and  102  adjacent to each other, in the length direction of the band-shaped coil  100 , and the straight portions  102  are accommodated in the respective gripping grooves  321 , whereby the band-shaped cell  100  is gripped. Therefore, it is possible for the conveyor  32  to convey the band-shaped coil  100  in a state of holding the straight portions  102  at regular intervals without displacing the straight portions. As shown in  FIGS.  2  and  3   , the side ends  103  of the band-shaped coil  100  protrude laterally on both sides in the moving direction of the conveyor  32 . It should be noted that, in  FIG.  1   , the band-shaped coil  100  to be gripped by the conveyor  32  is not shown. 
     Guide Member 
     As shown in  FIG.  3   , the guide members A are made from a metal band-shaped plate material, and provided in a substantially U-shape laterally along the pivot conveying unit  313  of the conveying rail  21 . In the guide members  4 , the inside of the U-shaped portion is provided so as to face the direction of the coil winding jig  2  in the vicinity of the both ends of the coil winding jig  2  in the axial direction (the vertical direction relative to the paper plane of  FIG.  1   , and the left-right direction in  FIG.  2   ) so as to sandwich the coil winding jig  2 , and is fixed to the conveying rail  31 . 
     The guide member A guides the side end  103  of the band-shaped coil  100  conveyed by the conveyor  32  along its own inner wall surface  41  from the introduction end  4   a  over to the discharge end  4   bb . The inner wall surface  41  of the guide member  4  is formed, by a curved surface which smoothly curves continuously so as to follow approximately ½ the range of the outer circumference of the coil winding jig  2 , from the introduction end  4   a  to the discharge end  4   bb . Approximately ½ the range of the outer circumference of the coil winding jig  2  corresponds to the range shown as the second half portion  313   b  of the pivot conveying unit  313  in  FIG.  10   . The guide member  4  smoothly guides in an arc shape so that the entirety of the band-shaped coil  100  follows the outer circumference of the coil winding jig  2 , by bringing the side end  103  introduced from the introduction end  4   a  into contact with the inner wall surface  41 , while being pivotally conveyed by the pivot conveying unit  313 . 
     As easily understood by referencing  FIG.  10   , the path curved from the introduction end  4   a  to the discharge end  4   bb  of the guide member  4  includes a diameter-reducing guide part  41   r  corresponding to the second half portion  313   b  of the pivot conveying unit  323 , and an extension guide part  41   m  connecting to this. The diameter-reducing guide part  41   r  is a guide part formed in the second half portion of pivot conveying of the band-shaped coil  100 , i.e. portion corresponding to the second half portion  313   b  of the pivot conveying unit  313 , so that the radius of curvature increases along the path of this pivot conveying and gradually reduces in diameter. The starting edge of the second half portion  313   b  of the pivot conveying unit  313  substantially corresponds to the starting edge of the diameter-reducing guide part  41   r,  and the end edge of the second half portion  313   b  of the pivot conveying unit  313  corresponds to the end edge  4   b  of the diameter-reducing guide part  41   r . The extension guide part  41   m  is a guide part linking to the end edge  4   b  of the diameter-reducing guide part  41   b  and extending a predetermined length maintaining the diameter by the curvature of this end edge  4   b.    FIG.  10    notes this extending length as an extension portion  313   e  linking to the end edge of the second half portion  313   b  of the pivot conveying unit  313 . This extension length is set; to a length which can abut, at least a pair of the straight portions  102  connected to the same side end  103  of the band-shaped coil  100 . 
     As shown in  FIG.  10   , the inner wall surface  41  of the introduction end  4   a  of the guide member  4  is arranged somewhat more to the outer side in the radial direction than the outer circumference of the coil winding jig  2 . However, the inner wall surface  41  gradually reduces in diameter smoothly as approaching the end edge  4   b  of the diameter-reducing guide part  41   r  from the introduction end  4   a.  The inner wall surface  41  at the end edge  4   b  of the diameter-reducing guide part  41   r  is arranged more to the inner side in the radial direction than the outer circumference of the coil winding jig  2 . For this reason, the inner wall surface  41  of the diameter-reducing guide part  41   r  of the guide member  4  guides the band-shaped coil  100  so as to gradually round into an arc of a smaller diameter than the outside diameter of the coil winding jig  2 , while contacting the side end  103  of the band-shaped coil  100 , as the band-shaped coil  100  enters the second half portion  313   b  from the first half portion  313   a  of the pivot conveying unit  313 . 
     The band-shaped coil  100  is gradually pressed toward the coil winding jig  2 , by being guided to the inner wall surface  41  of the diameter-reducing guide part  41   r  of the guide member  4 , as approaching the second half portion  313   b  from the first half portion  313   a  of the pivot conveying unit  313 . The straight portion  102  gripped by the conveyor  32  thereby forcibly separates from the gripping groove  321  so as to lift up, and gradually moves towards the inside of the comb teeth-shaped groove  23  of the coil winding jig  2 . The inner wall surface  41  of the diameter-reducing guide part  41   r  of the guide member  4  is arranged more to the inner side in the radial direction than the outer circumference of the coil winding jig  2 ; therefore, the straight portion  102  is completely inserted into the comb teeth-shaped groove  23  of the coil winding jig  2 . 
     Immediately following the end edge  4   b  of the diameter-reducing guide part  41   r,  the band-shaped coil  100  is further regulated until reaching the discharge end  4   bb , so that, the shape reduced in diameter in the course of reaching the end edge  4   b  does not spring back by the extension guide part  41   m . For this reason, the band-shaped coil  100  maintains a fixed diameter (curvature) reduced in diameter in the course of reaching the end edge  4   b,  detaches from the guide member  4  at the discharge end  4   bb , and is wound on the coil winding jig  2  by rotation of the coil winding jig  2 . It should be noted that, in  FIGS.  10  and  12   , the conveyor  32  is omitted from illustration, and the band-shaped coil  100  is shown to be simplified. In this case, the path length of the extension guide part  41   m  is set to a length capable of abutting at least a pair of the straight portions  102  linking to the same side end  103  of the band-shaped coil  100 ; therefore, spring back is effectively inhibited. 
     It should be noted the guide member  4  is not limited to a structure having the inner wail surface  41  which is continuous over the entirety of the pivot conveying unit  313  as in the present embodiment. The guide member  4 , although not illustrated, may be a structure arranging a plurality of guide rollers so as to follow the pivot conveying unit  313 , for example. However, in the viewpoint of configuring so as to be able to continuously guide the band-shaped coil  100  to the comb teeth-shaped groove  23  of the coil winding jig  2 , and be able to smoothly insert the straight portion . 102  into the comb teeth-shaped groove  23 , the guide member  4  preferably has the inner wall surface  41  contacting at the wall surface with the side end  103  at the second half portion  313   b  of the pivot conveying unit  313 . In the viewpoint of configuring so as to be able to smoothly guide the band-shaped coil  100  into an arc shape over the entirety of the pivot conveying unit  313 , and be able to smoothly insert the straight portion  102  into the comb teeth-shaped groove  23  of the coil winding jig  2 , the guide member  4  preferably has the inner wall surface  41  contacting at the wall surface with the side end  103  in the entirety of the pivot conveying unit  313  as in the present embodiment. 
     As shown in  FIGS.  1  and  2   , the guide member  4  has, at the side of: the introduction end  4   a  thereof, the pair of reforming portions  42  for causing the band-shaped coil  100  introduced to the pivot conveying unit  313  to forcibly deform and reform so as to curve into an arc shape along the outer circumference of the coil winding jig  2 . In the guide member  4 , the range in which the reforming portion  42  is provided is within the range of the first half portion  313   a  of the pivot conveying unit  313 . More specifically, the reforming portion  42 , for example, can be provided from the introduction end  4   a  of the guide member  4  over a range of approximately ½ to approximately ¾ of the first half portion  313   a  of the pivot conveying unit  313 . 
     The reforming portion  42  is configured by the inner wall surface  41  of the guide member  4  and guide plates  421 . The guide plates  421  are formed so as to smoothly curve in an arc shape along the curvature of the inner wall surface  41  of the guide member  4 . The guide plates  421 , similarly to the guide member  4 , are respectively arranged so as to sandwich the coil winding jig  2  from both end sides in the axial direction, and are fixed to the guide member  4 . In the reforming portion  42 , a reforming groove  422  pinching the side end  103  is formed between the inner wall surface  41  and guide plate  421 . The inner wall surface  41  of the reforming portion  42  contacts and supports the surface on the outer side in the radial direction of the side end  103  of the band-shaped coil  100 , and the guide plates  423  contact and support the surface on the inner side in the radial direction of the side end  103  of the band-shaped coil  100 . 
     The reforming portion  42  causes the side end  103  of the band-shaped coil  100  introduced to the introduction end  4   a  of the guide member  4  to forcibly deform so as to curve into an arc shape, by conveying while being accepted and clamped in the reforming groove  422 . The band-shaped coil  100  is reformed into an arc shape, at an early stage of introduction of the pivot conveying unit  313  before winding on the coil winding jig  2 , and the force trying to elastically recover to a flat shape while guided to an arc shape by the inner wall surface  41  of the guide member  4  subsequently is suppressed. Therefore, the band-shaped coil  100  is smoothly and precisely molded into the substantially cylindrical wound shape, in combination with being guided into the arc shape by the guide member  4 . 
     Coil Forming Method 
     Next, a method of forming the band-shaped coil  100  into a substantially cylindrical wound state by the coil forming apparatus  1  will be described. 
     First, the coil winding jig  2  is provided to be rotatable by the driving of a motor (not shown) inside the U-shaped portion of the conveying rail  31  of the coil forming apparatus  1 . After the coil winding jig  2  is provided in the coil forming apparatus  1 , the band-shaped coil  100  which is formed in advance in a long corrugated band shape is supplied to the conveyor  32  which is provided in the straight conveying unit  311  on the lower side of the conveying rail  31  by a coil feeding device or an operator (not shown). The band-shaped coil  100  is gripped by the conveyor  32  by inserting the first gripping claws  333  and the second gripping claws  336  of the respective piece members  33  of the conveyor  32  into the gaps between the adjacent straight portions  102  and  102 , and by accommodating the straight portions  102  in the gripping grooves  321 , respectively. 
     Thereafter, the conveyor  32  gripping the base-shaped coil  100  is pressed by a conveyer pressing device (not shown) or an operator, and the straight conveying unit  311  is moved toward the coil winding jig  2  so that the meshing groove  333   a  of the piece member  33  and the engaging portion  22   a  of the coil winding jig  2  are engaged with each other. When the coil winding jig  2  is rotationally driven in the direction d 1  after the meshing groove  333   a  and the engaging portion  22   a  are meshed with each other immediately below the coil winding jig  2 , the conveyor  32  moves the conveying rail  31  along the direction d 2  in synchronization with the rotation of the ceil winding jig  2 , and pivotally conveys the band-shaped coil  100  along the outer periphery of the coil winding jig  2  (coil conveying step). 
     When the conveyor  32  reaches the pivot conveying unit  313 , the side end  103  of the band-shaped coil  100  is first introduced into the reforming groove  422  of the reforming portion  42  from the introduction end  4   a  of the guide member  4 , and is pivotally conveyed while being sandwiched between the inner wall surface  41  and the guide plate  421 . Thus, the band-shaped coil IOC is forcibly deformed and reformed so as to be curved in an arc shape along the reforming groove  422  (reforming step). 
     The band-shaped coil  100  passing through the reforming portion  42  is guided so as to be gradually rounded in an arc shape while being pivotally conveyed along at least a portion of the cuter periphery of the coil winding jig  2  along the inner wall surface  41  of the guide member  4 , i.e., a range of approximately ½ the outer periphery of the coil winding jig  2 , accompanying the rotation of the coil winding jig  2 . 
     Since the curvature of the inner wall surface  41  of the guide member  4  gradually increases from the first half portion  313   a  to the second half portion  313   b  of the pivot conveying unit  313 , the side end  103  of the band-shaped coil  100  is pressed by the inner wall surface  41  so as to gradually decrease the diameter inwardly in the radial direction. Thus, the banc-shaped coil  100  is rounded to have a smaller diameter than the outer diameter of the coil winding jig  2 . The side end  103  which is pressed against the inner wall surface  41  gradually separates the straight portions  102  from the gripping grooves  321  toward the comb-shaped groove  23  of the coil winding jig  2  as the band-shaped coil  100  approaches the discharge end  4   bb  of the guide member  4 . As shown in  FIG.  10   , the straight, portions  102  completely detached from the gripping grooves  321  are inserted into the respective comb-shaped grooves  23  of the coil winding jig  2  in communication with the grapping grooves  321 , while being pressed against the inner wall surface  41  of the guide member  4  (guiding step). 
     The guiding step includes a diameter-reducing guide step and an extension guide step. In the diameter-reducing guide step, the band-shaped coil  100  is guided so as to gradually reduce in diameter accompanying pivoting, until the end edge  4   b  of the diameter-reducing guide part  41   r , in the second half portion of this pivot conveying. In the extension guide step, the band-shaped coil  100  is regulated so as to maintain the diameter by a fixed curvature until reaching the discharge end  4   bb  in the extension guide part  41   m , so that the shape reduced in diameter in the course of reaching the end edge  4   b  does net spring back. The path length of the extension guide part  41   m  is set to a length capable of abutting at least a pair of the straight portions  102  linking to the same side end  103  of the band-shaped coil  100 ; therefore, spring back is effectively inhibited. Subsequently, the band-shaped coil  100  is discharged from the discharge end  4   bb  of the guide member  4 , while being wound in the coil winding jig  2 , accompanying rotation of the coil winding jig  2 . 
     If the entirety of the conveyor  32  finishes moving along the conveying rails  31 , the band-shaped coil  100  is wound four, times around the coil winding jig  2  to be multiply wound, as shown in  FIG.  12   , by the straight portions  102  being introduced into the comb teeth-shaped grooves  23  in a layered manner. The band-shaped coil  100  is thereby easily molded into a substantially cylindrical wound state, as shown in  FIG.  13   . Since the straight portions  102  of the band-shaped coil  100  in the wound state is accommodated within the comb teeth-shaped grooves  23 , there is no concern of displacing. Therefore, the band-shaped coil  100  can stably hold the substantially cylindrical wound state. It should be noted that the band-shaped coil is not limited to being multiply wound on the coil winding jig  2 . 
     According to the above explained coil forming apparatus  1 , the following effects are exerted. That is, the coil forming apparatus I forms the band-shaped coil  100  in a wound state, and the banc-shaped coil  100  includes the plurality of straight portions  102  and the side ends  103  provided on both ends of the plurality of straight portions  102 . The coil forming apparatus  1  includes: the coil winding jig  2  that winds the band-shaped coil  100 , the coil winding jig  2  including the plurality of comb-shaped grooves  23  on the outer periphery thereof, each of which can hold a respective one of the plurality of straight portions  102  therein; the coil conveying mechanism unit  3  that pivotally conveys the band-shaped coil  100  along at. least a portion of the outer periphery of the coil winding jig  2 ; and the guide members  4  that are respectively provided in the vicinity of both ends of the coil winding jig  2  in the axial direction, and respectively guide the band-shaped coil  100  into an arc shape to insert into the plurality of comb-shaped grooves  23  while being in contact with the side ends  103 . The guide member  4  includes the diameter-reducing guide part  41   r  formed so as to gradually reduce in diameter accompanying pivoting at the second half portion of pivot conveying of the band-shaped coil  100 , and the extension guide part  41   m  linking to the end edge  4   b  of the diameter-reducing guide part  41  and extending a predetermined length maintaining the diameter by the curvature of the end edge  4   b.  Accordingly, the band-shaped coil  100  is gradually reduced in diameter by the diameter-reducing guide part  41   r  at the second half portion of pivot conveying, and spring back is suppressed by the extension guide part  41   m  linking to the end edge  4   b,  even when reaching the end edge  4   b  of the diameter-reducing guide part  41   r.  For this reason, the winding posture being distorted in the coil winding jig by spring back of the band-shaped coil is avoided. Therefore, it is possible to continuously insert the straight portion  102  of the band-shaped ceil  100  into the comb-shaped grooves  23  of the coil winding jig  2  and orderly wind In the coil winding jig  2 . It is thereby possible to mold the band-shaped coil  100  easily into the wound state without the straight portions  102  displacing. 
     In the guide member  4  of the present embodiment, the extension guide part.  41   m  has an extension length capable of abutting at least the pair of straight portions  102  linking to the same side end of the band-shaped coil  100 . Accordingly, spring back of the band-shaped coil  100  is effectively inhibited. 
     The coil forming method described above has the following advantageous effects. More specifically, the coil forming method according to the present embodiment forms the band-shaped coil  100  in a wound state, and the band-shaped coil  100  includes the plurality of straight portions  102  and the side ends  103  provided on both ends of the plurality of straight portions  102 , The coil forming method includes the coil conveying step of pivotally conveying the band-shaped coil  100  along at least a portion of the outer periphery of the coil winding jig  2 , the coil winding jig  2  including the plurality of comb-shaped grooves  23  on the outer periphery thereof, into which a respective one of the plurality of straight portions  102  can be inserted in the outer periphery, and being configured to wind the band-shaped coil  100 ; and the guiding step of guiding the band-shaped coil in an arc shape to respectively insert into the plurality of comb-shaped grooves, while providing each of the guide members  4  in the vicinity of both ends of the coil winding jig  2  in the axial direction, and contacting the guide member A with the side end  103 , in which the guiding step includes: the diameter-reducing guide step of guiding the band-shaped coil  100  so as to gradually reduce in diameter along the path of the pivot conveying at the second half portion of pivot conveying; and the extension guide step of guiding, immediately after diameter-reducing guide step, by extending the band-shaped coil by a predetermined length to maintain the diameter according to the curvature immediately following. Accordingly, immediately after the diameter-reducing guide step of guiding the band-shaped coil  100  so as to gradually reduce in diameter, it advances to the extension guide step immediately following of guiding by maintaining the diameter from the curvature to extend the band-shaped coil by a predetermined length. Therefore, the band-shaped coil  100  is suppressed from spring back. For this reason, in the band-shaped coil  100 , the winding posture being disturbed by spring back is avoided. 
     The extension guide step in the guiding step of the present embodiment maintains guidance over the extension length capable of abutting at least the pair of straight portions  102  linking to the same side end  103  of the band-shaped coil  100 . Accordingly, spring back of the band-shaped coil  100  is effectively inhibited. 
     EXPLANATION OF REFERENCE NUMERALS 
       1  coil forming apparatus 
       2  coil winding jag 
       23  comb teeth-shaped groove 
       3  coil conveying mechanism unit 
       313  pivot conveying unit 
       313   b  second half portion 
       313   e  extension region 
       4  guide member 
       4   b  end edge 
       4   bb  discharge end 
       41  inner wall surface 
       4   m  extension guide part 
       41   r  diameter-reducing guide part 
       100  band-shaped coil 
       102  straight portion 
       103  side end