Patent Publication Number: US-8534590-B2

Title: Coil winding system and method for fabricating molded coil

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of patent application Ser. No. 12/230,505, filed on Aug. 29, 2008 (herein incorporated by reference), which claims the foreign priority benefit under Title 35, United States Code, §119(a)-(d) of Japanese Patent Application Nos. 2007-260860 and 2007-260861, filed on Oct. 4, 2007, 2007-278948 and 2007-278949, filed on Oct. 26, 2007 and 2008-14550, filed on Jan. 25, 2008 in the Japan Patent Office, the disclosures of which are herein incorporated by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a coil winding system for fabricating a wound coil having a coil (solenoid) to be assembled into electromagnetic devices such as an electromagnetic valve and an electromagnetic actuator for example and to a method for fabricating a molded coil. 
     2. Description of Related Art 
     Heretofore, there have been known electromagnetic devices such as an electromagnetic valve that actuates a valve by attracting a movable core to a stationary core side by electromagnetic force generated by exciting a wound coil that composes a solenoid for example. Electrical insulation (isolation) of such electromagnetic devices has been maintained by coating an outer surface of the wound coil by a resin material by means of molding and the like. 
     Then, the present applicants have proposed a method of fabricating a bobbinless coil assembly by integrally molding a coil cover (coil coating member) made of a synthetic resin on an outer peripheral surface and both end surfaces in an axial direction, except of an inner surface, of a cylindrical bobbinless coil as shown in Japanese Patent Application Laid-open No. 2007-67090. 
     The present invention has been made in connection with this proposal and generally seeks to provide a coil winding device capable of stably disposing upper and lower plates above and under a claw section in preferably obtaining a bobbinless wound coil. 
     The present invention also seeks to provide a coil winding method capable of readily forming a bobbinless coil by winding a wire rod and of steadily securing isolation of the wound coil and to provide the wound coil. 
     The invention also seeks to provide a method for molding a solenoid by resin capable of assuring a favorable fluidity by fully filling the molten resin into a cavity for forming a thin portion on an outer end surface along an axial direction of a molded resin and to provide the molded resin. 
     The invention also seeks to provide a coil winding system that allows such a wound coil composed of the bobbinless coil to be readily and efficiently fabricated. 
     The invention primarily seeks to provide a method that allows a molded coil containing the wound coil composed of the bobbinless coil to be readily and efficiently fabricated. 
     SUMMARY OF THE INVENTION 
     In order to attain the aforementioned objects, the invention provides a coil winding system for winding a coil as a wound coil, including a coil winding device provided with an upper jig to which an upper plate is attached and a lower jig to which a lower plate is attached in such a manner that the upper and lower jigs are relatively displaceable, a wire rod supplying means for supplying a wire rod to be wound around the coil winding device as the coil and a tension device for applying predetermined tension to the wire rod supplied to the coil winding device, wherein the coil winding device has a claw section as a wire winding section around which the wire rod is wound between the upper and the lower plates and the claw section contains a plurality of split claws that slide in a radial direction when the upper jig is assembled coaxially with the lower jig. 
     According to the invention described above, the upper and lower plates are held while being separated by a predetermined distance when the upper jig to which the upper plate is attached is assembled with the lower jig to which the lower plate is attached by relatively displacing from each other. In succession, the wire rod is supplied from the wire rod supplying means to the coil winding device while applying the predetermined tension to the wire by the tension device, so that the wire rod is wound around the wire winding section provided on a peripheral surface of the claw section of the coil winding device. 
     As a result, according to the invention, the wound coil composed of the bobbinless coil may be formed readily and efficiently by holding the upper and lower plates separated by the predetermined distance by the upper and lower jigs and by winding the wire rod around the wire winding section on the peripheral surface of the claw section provided between the upper and lower plate. 
     In this case, the wound coil has a stacked coil having the coil stacked into a plurality of levels by the wire rod wound between the upper and lower plates and a weaving wire for holding the upper and lower plates by alternately weaving projections formed around an outer periphery of the upper and lower plates. Accordingly, the bobbinless coil in which no cylindrical coil bobbin is provided on the inner peripheral surface of the stacked coil may be held stably by the weaving wire without loosening the stacked coil. 
     Uniform holding force may be also generated in the peripheral direction by weaving the weaving wire around the side peripheral surface of the stacked coil and the uniform holding force can suitably hold the stacked coil composed of the bobbinless coil. 
     Still more, the invention allows a molded coil to be formed through steps of forming the stacked coil having the coil stacked into a plurality of levels by winding the wire rod between the upper and lower plates, forming the wound coil composed of the bobbinless coil by holding the upper and lower plates by the weaving wire by alternately weaving the projections formed around the outer periphery of the upper and lower plates and then loading the wound coil into a cavity of a die assembly and coating the wound coil by molten resin. 
     Thus, the invention allows the molded coil containing the wound coil composed of the bobbinless coil to be readily and efficiently formed by implementing the molding step of coating the wound coil by the molten resin after forming the stacked coil and forming the wound coil by holding the upper and lower plates of the stacked coil by the weaving wire. 
     Accordingly, the invention provides the coil winding system that allows the wound coil composed of the bobbinless coil to be readily and efficiently fabricated. The invention also provides the method that allows the molded coil containing the wound coil composed of the bobbinless coil to be readily and efficiently fabricated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an enlarged perspective view of a wound coil fabricated by means of a coil winding system according to an embodiment of the invention; 
         FIG. 2  is a longitudinal section view of the wound coil shown in  FIG. 1 ; 
         FIG. 3  is a plan view when an upper plate composing the wound coil described above is seen from above thereof; 
         FIG. 4  is a longitudinal section view of the wound coil seen along a line IV-IV in  FIG. 1 ; 
         FIG. 5  is a bottom view showing an under surface of a lower plate composing the wound coil; 
         FIG. 6  is a partially enlarged perspective view showing a guide slope provided on an upper surface of the lower plate; 
         FIG. 7  is a schematic structural perspective view of the coil winding system according to the embodiment of the invention; 
         FIG. 8  is a partially omitted exploded perspective view of a coil winding device composing the coil winding system; 
         FIG. 9  is an exploded perspective view of the coil winding device; 
         FIG. 10  is an exploded perspective view of an upper jig composing the coil winding device; 
         FIG. 11  is an exploded perspective view of a lower jig composing the coil winding device; 
         FIG. 12  is a partially sectional plan view of the lower jig from which an attachment plate is omitted; 
         FIG. 13  is a longitudinal section view showing a state before the upper jig is inserted into the lower jig; 
         FIG. 14  is a longitudinal section view showing a state during when the upper jig is inserted into the lower jig; 
         FIG. 15  is a longitudinal section view showing a state after when the upper jig has been inserted into the lower jig; 
         FIG. 16  is an enlarged longitudinal section view of a region denoted by a reference character P in  FIG. 15 ; 
         FIG. 17  is an enlarged longitudinal section view of a region denoted by a reference character Q in  FIG. 15 ; 
         FIG. 18  shows a state laid out in a peripheral direction in which a wire rod is wound around claws; 
         FIGS. 19A through 19C  are partially omitted perspective views showing a sequence how the wire rod is wound around the claw section provided between the upper and lower plates; 
         FIG. 20  is a partially cut-away side view showing a state when the wire rod is wound around first through third split claws composing the claw section by representing peripheral faces of the first through third split claws in flat for convenience sake; 
         FIG. 21  is a partially longitudinal section view showing a state in which the wire rod is folded back and is stacked; 
         FIG. 22  is a perspective view showing states of weaving circular arc projections formed respectively around an outer peripheral portion of the upper and lower plates by a weaving wire in an elapsed time-series manner; 
         FIG. 23  is a schematic structural longitudinal section view of a die assembly for carrying out a method of molding the wound coil; 
         FIG. 24  is a schematic structural longitudinal section view of the die assembly shown in  FIG. 23  that is clamped after loading a form-to-be-molded into a cavity of the assembly; 
         FIG. 25  is a schematic structural longitudinal section view of the die assembly in a state of injecting molten resin from gates in the clamped state; 
         FIG. 26  is a schematic structural longitudinal section view of the die assembly opened to take out the molded resin; 
         FIG. 27  is a plan view of the die assembly showing positional relationship among the projections and the gates of a first plate; 
         FIG. 28  is a partially enlarged longitudinal section view showing a state in which a flow of the molten resin injected from the gate to a thin molding airspace portion is urged by the projection; 
         FIG. 29A  is a perspective view showing the coil-to-be-molded and  FIG. 29B  shows a perspective view of the molded resin; and 
         FIG. 30  is a block diagram showing steps of fabricating the molded coil. 
     
    
    
     PREFERRED EMBODIMENTS OF THE INVENTION 
     Next, preferred embodiments of the invention will be explained below with reference to the appended drawings.  FIG. 1  is an enlarged perspective view of a wound coil fabricated by means of a coil winding system according to an embodiment of the present invention,  FIG. 2  is a longitudinal section view of the wound coil shown in  FIG. 1 ,  FIG. 3  is a plan view when an upper plate composing the wound coil described above is seen from above thereof,  FIG. 4  is a longitudinal section view of the wound coil seen a line IV-IV in  FIG. 1 ,  FIG. 5  is a bottom view showing an under surface of a lower plate composing the wound coil,  FIG. 6  is a partially enlarged perspective view showing a guide slope provided on an upper surface of the lower plate and  FIG. 7  is a schematic structural perspective view of the coil winding system according to the embodiment of the invention. 
     At first, the wound coil  100  in which a wire rod  106  is wound by means of the coil winding system  10  shown in  FIG. 7  will be explained. It is noted that in a step of winding the wire rod  106  described below, an axial direction will be defined as a column direction of the wire rod  106  and a radial direction as a level direction. 
     As shown in  FIGS. 1 and 2 , the wound coil  100  includes an upper plate  102  (the upper plate  102  has an upper surface  102   a  and an under surface  102   b ) made of a resin material and having a through hole  101  through which an upper jig  12  of the coil winding system  10  is inserted and a lower plate  104  (the lower plate  104  has an upper surface  104   a  and an under surface  104   b ) made of a resin material and having a through hole  103 . 
     The wound coil  100  also includes a stacked coil  108  having a coil formed by winding and stacking a wire rod (conductive wire) into a plurality of levels and by sandwiching between the upper and lower plates  102  and  104 , and a weaving wire  116  for holding the upper and lower plates  102  and  104  by alternately weaving circular arc projections  114   a  and  114   b  of the upper and lower plates  102  and  104  disposed in zigzag without being superimposed in a vertical direction. It is noted that no core member such as a coil bobbin is provided within a coil inner peripheral surface  120  of the stacked coil  108  and the surface  120  is exposed to the outside. 
     The circular arc projections  114   a  and  114   b  protruding in a radial outward direction from the outer peripheral portions of the upper and lower plates  102  and  104  have first guide grooves  122  formed so as to guide the weaving wire  116  in weaving the weaving wire  116  (see  FIGS. 3 and 5 ). As shown in  FIG. 4 , a bottom inner wall of the first guide groove  122  is formed so as to have a curved face  123  whose center part is slightly raised when seen longitudinally in section, so that the weaving wire  116  may be readily woven to the circular arc projections  114   a  and  114   b  and the weaving wire  116  is kept to have adequate tensile force. 
     It is noted that the circular arc projections  114   a  are provided at five places of the upper plate  102  (see  FIG. 3 ) and the circular arc projections  114   b  are provided at six places of the lower plate  104  (see  FIG. 5 ). The first guide groove  122  provided on the circular arc projection  114   a  of the upper plate  102  is formed so as to open upward and the first guide groove  122  provided on the circular arc projection  114   b  of the lower plate  104  is formed so as to open downward respectively to suitably hold the weaving wire  116 . 
     As shown in  FIG. 1 , the upper surface  102   a  of the upper plate  102  is provided with a pin hole  119   a  into which a first pin  17   a  of the upper jig  12  described later (see  FIGS. 9 and 10 ) is inserted to position the upper plate  102  at predetermined position with respect to the upper jig  12  by inserting the first pin  17   a  into the pin hole  119   a.    
     Further, as shown in  FIG. 5 , the under surface  104   b  of the lower plate  104  is provided with a pin hole  119   b  into which a second pin  17   b  of the lower jig  14  described later (see  FIGS. 9 and 11 ) is inserted to position the lower plate  104  at predetermined position with respect to the lower jig  14  by inserting the second pin  17   b  into the pin hole  119   b . It is noted that the pin holes  119   a  and  119   b  are formed so as not penetrate through the upper plate  102  or the lower plate  104  and so as to close on their way. It suitably prevents an outer surface of the stacked coil  108  sandwiched between the upper and lower plates  102  and  104  from being damaged. 
     As shown in  FIG. 5 , the lower plate  104  is provided with a first winding securing section  110   a  having substantially a shape of L in transverse section and protruding in the radial outward direction to wind and secure a winding beginning portion of the wire rod  106  and a second winding securing section  110   b  having substantially a shape of L in transverse section to wind and secure a winding ending portion of the wire rod  106 . It is noted that the first and second winding securing sections  110   a  and  110   b  are caulked respectively with a pair of terminals  152   a  and  152   b  (see  FIG. 29 ) in a next process to electrically connect the winding beginning portion of the wire rod  106  with the winding ending portion thereof. 
     Further, as shown in  FIG. 5 , a rectangular plate portion  124  is integrally formed between the outer peripheral surface of the lower plate  104  and the first and second winding securing sections  110   a  and  110   b . The plate portion  124  of the under surface  104   b  of the lower plate  104  is provided with a curved second guide groove  126  formed so as to guide the winding beginning portion of the wire rod  106  secured to the first winding securing section  110   a  from the first winding securing section  110   a  toward an outer peripheral part of the lower plate  104 . 
     Still more, as shown in  FIGS. 2 ,  5  and  6 , an inner peripheral portion of the lower plate  104  is provided with a cylindrical projection  128  formed so as to slightly extend in the axial direction (at the upper and lower faces  104   a  and  104   b  of the lower plate  104 ). Further, as shown in  FIG. 6 , the upper surface  104   a  of the lower plate  104  is provided with a guide slope  130  formed as a concave groove in section that extends in a tangent direction of the cylindrical projection  128  to guide the winding beginning portion of the wire rod  106  from the outer peripheral portion of the lower plate  104  to the inner peripheral portion thereof. As shown in  FIG. 20 , the guide slope  130  is formed so as to have a slope (groove bottom) inclined by a predetermined angle so that a depth thereof is shallow on the inner peripheral side and is gradually deepened on the outer peripheral side. 
     One side wall  132  of the guide slope  130  substantially orthogonal to the slope described above is provided with two ribs  134  for example which are separated by a predetermined distance and bulge in a horizontal direction toward the slope as shown in  FIG. 6 . These ribs  134  abut the wire rod  106  guided along the guide slope  130  to block molten resin from being filled into the guide slope  130  along the wire rod  106  when the wound coil is molded in the following process. As a result, it becomes possible to suitably prevent the molten resin from entering the coil inner peripheral surface  120 . It is noted that the number of the ribs  134  is not limited to be a plural number and may be one or more. 
     Still more, as shown in  FIG. 5 , the circular arc projection  114   b  of the lower plate  104  is provided with a notch  136  formed so as to anchor a weaving beginning portion of the weaving wire  116  and the other circular arc projection  114   b  is provided with another notch  136  formed so as to anchor a weaving ending portion of the weaving wire  116 . 
     As shown in  FIG. 21 , the under surface  102   b  of the upper plate  102  facing the lower plate  104  is provided with third guide grooves  138 , i.e., a plurality of grooves each having a circular arc in longitudinal section juncturally formed. The third guide groove  138  exhibits its function of guiding and aligning the wire rod  106  when the wire rod  106  is folded and is laminated into a plurality of levels. 
     Next, the coil winding system  10  of the present embodiment will be explained with reference to  FIGS. 7 and 8 .  FIG. 8  is a partially omitted exploded perspective view of a coil winding device composing the coil winding system. 
     This coil winding system  10  includes a coil winding device  15  composed of the upper jig  12  provided liftably along the vertical direction by means of an elevation mechanism not shown and a lower jig  14  supported on a base not shown rotatably along a direction of an arrow under a rotating and driving action of a motor M. 
     The coil winding system  10  also includes a nozzle  30  for feeding the wire rod  106  supplied from a wire rod supplying source  17  to the coil winding device  15 , a triaxial actuator mechanism  32  composed of a plurality of assembled linear actuators to displace the nozzle  30  in triaxial directions of XYZ orthogonal from each other under a guiding action of a guide rail not shown and a tension device  34  for applying an adequate tension to the wire rod  106  fed from the nozzle  30 . It is noted that the nozzle  30 , the triaxial actuator mechanism  32  and the wire rod supplying source  17  function as a wire rod feeding means. 
       FIG. 9  is an exploded perspective view of the coil winding device,  FIG. 10  is an exploded perspective view of the upper jig composing the coil winding device,  FIG. 11  is an exploded perspective view of the lower jig composing the coil winding device and  FIG. 12  is a partially sectional plan view of the lower jig from which an attachment plate is omitted. As shown in  FIGS. 9 and 10 , the upper jig  12  is composed of a upper jig body  210  for attaching and latching the upper plate  102  and a tapered portion  220  that is inserted into an opening of a claw section  240  of the lower jig  14  described later to expand the claw section  240  (split claws). 
     As shown in  FIG. 10 , the upper jig body  210  has a thick disk-like attachment seat  211  having a attachment surface  211   a  (see  FIGS. 13 through 15 ) formed so as to accommodate the upper surface  102   a  of the upper plate  102  and a insertion rod portion  215  extending downward perpendicularly from a center of the attachment seat  211 . 
     The attachment seat  211  is liftably linked by means of the elevation mechanism not shown, is provided with the attachment surface  211   a  that abuts the upper surface  102   a  of the upper plate  102  at the under surface thereof and is provided with the first pin  17   a  protruding downward to relatively position the upper plate  102  fitted to the attaching surface  211   a . It is noted that the upper plate  102  is attached to the attaching surface  211   a  of the attachment seat  211  by means of opening claws  213  (see  FIG. 13 ) that open in the radial direction. 
     The insertion rod portion  215  is substantially a cylindrical column to be inserted into the claw section  240  of the lower jig  14  described later and has a ringed tapered surface  216  at a lower end thereof formed so as to be readily inserted. 
     The insertion rod portion  215  is also provided with a key groove  217  formed at the lower part thereof along the perpendicular direction so that a key  231  (see  FIGS. 14 and 15 ) provided in the lower jig  14  is to be inserted therein. Thereby, relative position in the peripheral direction of the insertion rod portion  215  (the upper jig  12 ) and the lower jig  14  is determined. 
     Still more, the insertion rod portion  215  is provided with a locking groove  218  around the lower part thereof so that a locking piece  232  of the lower jig  14  is inserted into the locking groove  218  when the upper jig  12  is inserted into the lower jig  14  (see  FIG. 15 ). It prevents the upper jig  12  from slipping out after inserting the upper jig  12  into the lower jig  14 . It is noted that the locking piece  232  is provided with a cylinder not shown at an underside thereof and the locked state is released when a piston rod of the cylinder presses a lower part of the locking piece  232  and the locking piece  232  separates from the locking groove  218 . 
     The tapered portion  220  is formed substantially into an inverted truncated cone so as to be inserted into the claw section  240  in succession after inserting the lower part of the insertion rod portion  215  into the claw section  240  and has a tapered surface  221  around a surface thereof. The tapered portion  220  is provided with an insertion hole  222  that penetrates through the tapered portion  220  in the axial direction and the insertion rod portion  215  is inserted through the insertion hole  222 . 
     There are also provided with two threaded rods  223  above the tapered portion  220 . The two threaded rods  223  are to be screwed into the two screw holes  214  of the attachment seat  211 . They are arranged such that position of lower ends of the two threaded rods  223  may be controlled by fastening nuts  224  to upper ends of the respective threaded rods  223  and by locking the nuts  224  to the attachment seat  211 . 
     The lower ends of the threaded rods  223  butt an upper surface of the tapered portion  220 , so that the tapered portion  220  is set at predetermined level controlled by height of the threaded rods  223  with respect to the attachment seat  211 . It is noted that a key not shown guides the tapered portion  220  with respect to the body  210  of the upper jig in the perpendicular direction and holds the tapered portion  220  so as not to slip out of the body  210 . 
     A compression coil spring  225  is interposed between the tapered portion  220  and the attachment seat  211  so that the tapered surface  221  of the tapered portion  220  suitably butts the tapered surface  240   a  of the claw section  240  (see  FIG. 13 ) when the upper jig  12  is inserted into the claw section  240 . 
     As shown in  FIGS. 8 and 11 , the lower jig  14  has a substantially cylindrical body  230  of the lower jig, a pedestal  230   a  provided on the lower jig body  230  described above and is composed of a flange whose diameter is enlarged, a ringed plate  261  inserted within a circular concave portion formed in the pedestal  230   a , the claw section  240  having the first through third split claws  241   a  through  241   c  displaceably supported along the radial direction of the ringed plate  261  and whose diameter is enlarged along the radial outward direction when the tapered portion  220  of the upper jig  12  is inserted and a pair of latching sections  212  that protrude in directions orthogonal to an axial line of the lower jig body  230  for latching one winding starting end portion of the wire rod  106  and the weaving wire  116 . 
     The lower jig  14  also has three radial springs  251  that press the first through third split claws  241   a  through  241   c  of the claw section  240  in radial inner directions by their spring force and six thrust springs  265  that press the claw section  240  upward by their spring force as shown in  FIG. 11 . 
     The lower jig body  230  is arranged so that it is appropriately rotated by the motor M. The lower jig body  230  is provided with the key  231  that is inserted into the key groove  217  of the upper jig  12  and the locking piece  232  that engages with the locking groove  218  of the upper jig  12  (see  FIG. 15 ). 
       FIGS. 13 ,  14  and  15  are longitudinal section views showing states before the upper jig is inserted into the lower jig, during when the upper jig is inserted into the lower jig and after when the upper jig has been inserted into the lower jig. Although the claw section  240  is cylindrical when it is closed, it has the first through third split claws  241   a  through  241   c  whose horizontal section is circular arc when it is split in the peripheral direction. Each of the first through third split claws  241   a  through  241   c  is arranged to be slidable along the radial direction and is pressed toward the radial inner direction by the radial spring  251 . 
     That is, when the upper jig  12  is not inserted into the claw section  240 , each of the first through third split claws  241   a  through  241   c  is pressed toward the radial inner direction by the spring force of the radial spring  251  and the claw section  240  is closed like a cylinder with its diameter reduced. When the upper jig  12  is inserted into the claw section  240  on the other hand, each of the first through third split claws  241   a  through  241   c  is displaced in the radial outer direction by going against the spring force o f the radial spring  251  and the claw section  240  is opened with its diameter enlarged. 
     An inner peripheral surface of each of the first through third split claws  241   a  through  241   c  is formed to be a tapered surface  240   a  whose diameter is gradually reduced on the lower side as shown in  FIG. 13 . An inner peripheral surface  240   b  whose inner diameter is constant is formed below the tapered surface  240   a.    
     Each of the first through third split claws  241   a  through  241   c  is provided with a peripheral groove  242  along the peripheral direction on the lower side of the outer peripheral surface thereof as shown in  FIG. 11 . A narrow and constricted peripheral groove  242  is also provided at the part where the peripheral groove  242  of each of the first through third split claws  241   a  through  241   c  is formed such that a pair of protrusions  252   a  of a guide member  252  described later slidably pinch the neck portion  247 . The neck portion  247  is also provided with a spring hole  242   a  by an outer side face thereof so that the radial spring  251  is fitted into the spring hole  242   a  to position the guide member  252 . 
     Each of the first through third split claws  241   a  through  241   c  is provided with a first stepped portion  243  that extends in the peripheral direction on an upper part of the outer peripheral surface thereof and a second stepped portion  244  that extends in the peripheral direction on a lower part of the outer peripheral surface thereof. The first and second stepped portions  243  and  244  are provided respectively at positions separated by a predetermined distance along the axial direction of the claw section  240 . Here, the first stepped portion  243  is arranged so as to butt an inner lower face  140  of the upper plate  102  as shown in  FIG. 16  and the second stepped portion  244  is arranged so as to butt an inner upper surface  142  of the lower plate  104  as shown in  FIG. 17 , respectively, when the claw section  240  is opened.  FIGS. 16 and 17  are enlarged longitudinal section views of regions denoted by reference characters P and Q, respectively, in  FIG. 15 . 
     Each of the first through third split claws  241   a  through  241   c  is provided with a latching flange  245  formed into a circular arc when seen horizontally in section at the lower end portion thereof. The latching flange  245  is arranged so as to be latched by a raised portion  262  of the ringed plate  261  when the claw section  240  is closed (see  FIG. 13 ). 
     As shown in  FIG. 7 , a peripheral surface of the claw section  240  that functions as a wired section to be wound by the wire rod  106  is provided so as to be exposed between the upper and lower plates  102  and  104  separated by the predetermined distance along the vertical direction when the upper jig  12  is coaxially assembled with the lower jig  14 . This peripheral surface of the claw section  240  is formed by the peripheral surfaces of the first through third split claws  241   a  through  241   c  separated with clearances of a predetermined angle in the peripheral direction. 
     Here, a plurality of chases  246  that extends in parallel along the horizontal direction and that guides the wire rod  106  wound around the peripheral surface is formed around the peripheral surface of the first and second split claws  241   a  and  241   b  as shown in  FIG. 18 . The peripheral surface of the third split claw  241   c  is a smoothly-shaped flat surface  248  around which no irregularity is formed. This smoothly-shaped flat surface  248  achieves a smooth shift of the wire rod  106  wound around the peripheral surface in transferring to a next row. 
     As shown in  FIG. 12 , the three radial springs  251  are arranged so as to be attached on the upper surface of the pedestal  230   a  of the lower jig body  230  through the guide members  252 , when seen horizontally, by being separated equiangularly (every) 120° in the peripheral direction and to be guided along the radial direction by the guide members  252 . 
     The guide member  252  is provided, at one end portion thereof along the axial direction, with the pair of protrusions  252   a  that protrude substantially in parallel toward the first through third split claws  241   a  through  241   c . The pair of protrusions  252   a  is arranged so as to be inserted into the peripheral groove  242  of each of the first through third split claws  241   a  through  241   c  and to slidably sandwich the neck portion  247  of each of the first through third split claws  241   a  through  241   c . Thereby, each of the first through third split claws  241   a  through  241   c  is provided slidably on the upper part of the lower jig body  230  along the radial direction. 
     As shown in  FIG. 11 , a ringed attachment plate  253  on which the lower plate  104  is fitted is fixed on the guide member  252 . This attachment plate  253  is provided, on an upper surface thereof, with a second pin  17   b  for positioning the lower plate  104  at predetermined position with respect to the lower jig  14  and with rectangular concave portions  254  into which the guide members  252  are fitted. 
     As shown in  FIG. 12 , the six thrust springs  265  are compression coil springs for example and are arranged so as to be fitted into spring holes formed within the circular concave portion of the pedestal  230   a  of the lower jig body  230  and so as to be separated equiangularly (every 60°) along the peripheral direction. 
     As shown in  FIGS. 11 and 13 , the ringed plate  261  is disposed on and is uniformly supported by the six thrust springs  265 . The claw section  240  is disposed on the upper surface of the ringed plate  261 . That is, the six thrust springs  265  are arranged so as to press the claw section  240  upward through the ringed plate  261 . 
     The ringed plate  261  is provided, at an inner peripheral portion thereof, with the raised portion  262  thickly formed as compared to an outer peripheral portion thereof. That is, the raised portion  262  is provided so that it butts and latches the latching flange  245  of each of the first through third split claws  241   a  through  241   c  when the upper jig  12  is not inserted into the claw section  240  and the claw section  240  is closed. That is, the raised portion  262  functions as a stopper for controlling the displacement of the first through third split claws  241   a  through  241   c  in the radial inner direction when the claw section  240  is closed. 
     The coil winding system  10  of the present embodiment is constructed basically as described above. Next, operations of the coil winding system  10  will be explained below. 
     A preliminary process carried out before winding the wire rod  106  will be briefly explained at first. The upper jig  12  attached with the upper plate  102  and coaxially separated from the lower jig  14  attached with the lower plate  104  as shown in  FIG. 8  is lowered toward the lower jig  14  by means of the elevation mechanism not shown to assemble the upper jig  12  with the lower jig  14 . 
     Here, the tapered portion  220  of the upper jig  12  is inserted into the claw section  240  and presses the first through third split claws  241   a  through  241   c  in the radial outward direction. Then, the first through third split claws  241   a  through  241   c  slide in the radial outward direction and the upper jig  12  is assembled with the lower jig  14 . When the upper and lower jigs  12  and  14  are assembled, the upper and lower plates  102  and  104  are held while separating from each other by a predetermined distance. Thus, the preliminary process for winding the wire rod  106  around the peripheral surface (wound section) of the claw section  240  is completed. 
     Operations for assembling the upper jig  12  with the lower jig  14  will be explained in detail below with reference to  FIGS. 13 through 17 . 
     As shown in  FIG. 13 , the upper plate  102  is attached to the under surface (the attaching surface  211   a ) of the attachment seat  211  of the upper jig  12  while aligning the first pin  17   a  with the pin hole  119   a . Meanwhile, the lower plate  104  is attached to the upper surface  253   a  of the attachment plate  253  of the lower jig  14  while aligning the second pin  17   b  with the pin hole  119   b.    
     After attaching the upper and lower plates  102  and  104  respectively to the upper and lower jigs  12  and  14 , the upper jig  12  is lowered by the elevation mechanism not shown while aligning the key  231  of the lower jig  14  with the key groove  217  of the upper jig  12  to insert the insertion rod portion  215  of the upper jig  12  into the opening of the claw section  240  of the lower jig  14 . 
     When the insertion rod portion  215  butts the inner peripheral surface  240   b  of the first through third split claws  241   a  through  241   c  after that, the claw section  240  starts open because the first through third split claws  241   a  through  241   c  slide in the radial outward direction by going against the spring force of the radial spring  251 . 
     When the tapered surface  221  of the tapered portion  220  is lowered further while butting the tapered surface  240   a  of the first through third split claws  241   a  through  241   c , each of the first through third split claws  241   a  through  241   c  slides further in the radial outward direction. Then, when the latching flange  245  of each of the first through third split claws  241   a  through  241   c  butts an inner peripheral surface  253   b  of the attachment plate  253  as shown in  FIG. 15 , the sliding movement of each of the first through third split claws  241   a  through  241   c  in the radial outward direction is restricted. 
     Here, the first through third split claws  241   a  through  241   c  are pressed by the respective thrust springs  265  through the ringed plate  261 , so that they may be pressed upward uniformly and a gap G is created between the second stepped portion  244  on the lower side of the first through third split claws  241   a  through  241   c  and the inner peripheral upper end surface  142  of the lower plate  104  as shown in  FIGS. 13 and 14 . 
     When the upper jig  12  is lowered further and the under surface  261   a  of the ringed plate  261  butts the upper surface  230   a  of the lower jig body  230 , the upper jig  12  stops from being lowered. At this time, each of the first through third split claws  241   a  through  241   c  slides downward along with the lowering movement of the upper jig  12  by going against the pressing force of each thrust spring  265 . 
     Here, the inner peripheral lower end surface  140  of the upper plate  102  butts the first stepped portion  243  on the upper side of the first through third split claws  241   a  through  241   c  as shown in  FIG. 16  in the upper region P of the first through third split claws  241   a  through  241   c . Meanwhile, the inner peripheral upper end surface  142  of the lower plate  104  butts the second stepped portion  244  on the lower side of the first through third split claws  241   a  through  241   c  as shown in  FIG. 17  in the lower region Q of the first through third split claws  241   a  through  241   c.    
     Specifically, because each of the first through third split claws  241   a  through  241   c  is pressed upward in advance by the spring force of the thrust spring  265  and the gap G is created as shown in  FIGS. 13 and 14 , the second stepped portion  244  on the lower side butts the inner peripheral upper end surface  142  of the lower plate  104  after when the inner peripheral upper end surface  142  of the lower plate  104  is positioned right under the second stepped portion  244  of the lower side of each of the first through third split claws  241   a  through  241   c  in the lower region Q. 
     As a result, it becomes possible to prevent such a trouble that an outer peripheral surface of a split claw not shown that has no thrust spring  265  and slides only in the radial outward direction otherwise butts an inner peripheral surface  103   a  of the lower plate  104  (see  FIG. 17 ) for example. 
     Thus the upper jig  12  is coaxially assembled with the lower jig  14  and is locked by the locking piece  232  of the lower jig  14  that engages with the locking groove  218 . 
     In the state when the upper jig  12  is thus assembled with the lower jig  14 , an axial length L between the under surface (the attaching surface  211   a ) of the attachment seat  211  in the upper jig  12  and the upper surface  253   a  of the attachment plate  253  in the lower jig  14  is at a predetermined value as shown in  FIG. 15 . Position of enlarged outer periphery of each of the first through third split claws  241   a  through  241   c , i.e., a radial length D, is also set at a predetermined value. 
     Here, respective levels in the axial direction of the first stepped portion  243  formed on the upper side and of the second stepped portion  244  formed on the lower side of the first through third split claws  241   a  through  241   c  are set at position where compression load is applied respectively by the inner peripheral lower end surface  140  of the upper plate  102  and the inner peripheral upper end surface  142  of the lower plate  104 . 
     As a result, the upper plate  102  is sandwiched at the predetermined position, i.e., restrained, between the under surface (the attaching surface  211   a ) of the attachment seat  211  and the first stepped portion  243  of the first through third split claws  241   a  through  241   c  and the lower plate  104  is restrained between the upper surface  253   a  of the attachment plate  253  and the second stepped portion  244  of the first through third split claws  241   a  through  241   c.    
     More specifically, the upper plate  102  receives pressure A 2  that perpendicularly presses down the upper surface of the upper plate  102  from the under surface (the attaching surface  211   a ) of the attachment seat  211  (see  FIG. 15 ) and in the same time, receives a compression load (pressure A 3 : see  FIGS. 15 and 16 ) that presses the inner peripheral lower end surface  140  of the upper plate  102  upward in the axial direction from the first stepped portion  243  of the first through third split claws  241   a  through  241   c.    
     Still more, the lower plate  104  receives pressure A 6  that perpendicularly presses up the under surface of the lower plate  104  from the upper surface  253   a  of the attachment plate  253  (see  FIG. 15 ) and in the same time, receives a compression load (pressure A 5 : see  FIGS. 15 and 17 ) that presses the inner peripheral upper end surface  142  of the lower plate  104  downward in the axial direction from the second stepped portion  244  of the first through third split claws  241   a  through  241   c . Then, a predetermined clearance is formed between the first through third split claws  241   a  through  241   c  and the through hole  103  of the lower plate  104  as shown in  FIG. 17 . 
     In the state in which the upper jig  12  is thus assembled with the lower jig  14 , the upper and lower plates  102  and  104  are restrained at the predetermined position with respect to the opened claw section  240  and the distance between the upper and lower plates  102  and  104  is set at a predetermined width. 
     In other words, because the outer peripheral surface of the claw section  240  becomes a core, the upper plate  102  becomes an upper flange and the lower plate  104  becomes a lower flange, it becomes possible to form a structure similar to a bobbin having upper and lower flanges, i.e., an imaginary bobbin, and to readily wind the wire rod  106 . Thereby, it becomes possible to wind the wire rod  106  neatly between the upper and lower plates  102  and  104  and to obtain the stacked coil  108  whose winding formation is not distorted, i.e., in which the wire rods  106  are well arrayed in the axial direction. 
     In succession, a method for winding the wire rod  106  between the upper and lower plates  102  and  104  held by the upper and lower jigs  12  and  14  as described above will be explained.  FIG. 18  shows a state laid out in the peripheral direction in which the wire rod is wound around claws,  FIGS. 19A through 19C  are partially omitted perspective views showing a sequence how the wire rod is wound around the claw section provided between the upper and lower plates and  FIG. 20  is a partially cut-away side view showing a state when the wire rod is wound around the first through third split claws composing the claw section by representing peripheral surfaces of the first through third split claws in flat for convenience sake. 
     First, in the state in which the motor M is powerless and the upper and lower jigs  12  and  14  coaxially assembled are at rest, the nozzle  30  is displaced under the driving action of the triaxial actuator mechanism  32  to latch one winding starting end of the wire rod  106  fed from the nozzle  30  to the latching section  212  of the lower jig body  230 . Then, as shown in  FIG. 19A , the wire rod  106  is wound once around an outer peripheral surface of a first winding securing section  110   a  provided on the left side of the lower plate  104  from the lower side thereof clockwise as shown by arrows a 1  and a 2  in the figure. It is noted that the wire rod  106  fed from the nozzle  30  is tensioned adequately by the tension device  34 , so that it is possible to suitably prevent the wound wire rod  106  from becoming loose. 
     Next, the nozzle  30  is displaced along the horizontal direction under the driving action of the triaxial actuator mechanism  32  to insert the wire rod  106  along a second guide groove  126  formed at an under surface of a second winding securing section  110   b  on the right side of the lower plate  104  as shown in a partial perspective view in  FIG. 19A . Then, the wire rod  106  is guided from the outer peripheral portion to the inner peripheral portion of the lower plate  104  so that it is guided along the guide slope  130  formed on the upper surface  104   a  of the lower plate  104 . 
     When the wire rod  106  is guided along the slope of the guide slope  130  and reaches a lowest part of the flat surface  248  of the third split claw  241   c , the motor M is actuated to rotate the upper and lower jigs  12  and  14  integrally in a direction of an arrow A. Thereby, the wire rod  106  is guided by the groove  246  of the first and second split claws  241   a  and  241   b  and reaches again the flat surface  248  of the third split claw  241   c  as shown in  FIG. 20 . At this time, because the peripheral surface of the third split claw  241   c  is formed by the flat surface  248  and does not restrain the winding direction of the wire rod  106  at all, it can shift the wire rod  106  to a next row smoothly. 
     The nozzle  30  is also displaced upward and the wire rod  106  is wound by plural times along the direction of rows of the peripheral surfaces of the first through third split claws  241   a  through  241   c  (axial direction) as indicated by an arrow a 4  (see  FIG. 19B ). Because the nozzle  30  reciprocates along the axial direction, the wire rod  106  is sequentially laminated in the radial direction of the peripheral surface of the claw section  240  as shown in  FIG. 19   c.    
     After forming the stacked coil  108  composed of a plurality of levels of the wire rod  106  fed by rotating the upper and lower jigs  12  and  14  in a body and reciprocating the nozzle  30  by a plurality of times between the lower plate  104  and the upper plate  102 , the winding ending portion of the wire rod  106  is guided from the inner peripheral portion to the outer peripheral portion of the upper surface  104   a  of the lower plate  104  and is wound once an outer peripheral surface of the second winding securing section  110   b  on the right side of the lower plate  104  from above clockwise as indicated by arrows a 5  through a 7  in  FIG. 19C  in the state when the rotation of the upper and lower jigs  12  and  14  is stopped. Then, the winding ending portion of the wire rod  106  is cut by a cutter means not shown. 
     Thus, in the state in which the upper and lower jigs  12  and  14  are coaxially assembled and the upper and lower plates  102  and  104  are separated by the predetermined distance on the claw section  240 , the stacked coil  108  in which the wire rod  106  is neatly wound and is arrayed in the axial direction may be obtained between the upper and lower plates  102  and  104  that are set to have the predetermined width (see a block E in  FIG. 30 ). 
     Still more, because the winding beginning and ending portions of the stacked coil  108  exposed to the outside are secured respectively by the adjoining first and second winding securing sections  110   a  and  110   b  and are disposed in cross by being separated respectively at the upper and lower surfaces of the plate portion  124  of the lower plate  104 , it becomes possible to secure isolation quality of the stacked coil  108  including the winding beginning and ending portions. 
     Next, a method for weaving the weaving wire  116  for vertically holding the stacked coil  108  composed of the bobbinless coil will be explained below with reference to  FIG. 22 . It is noted that how one weaving beginning end of the weaving wire  116  is secured to the latching section  212  is the same with the case of forming the stacked coil  108  by winding the wire rod  106 , its explanation will be omitted here. Still more, although the following explanation will be made by using the wire rod  106  (conductive line) fed from the nozzle  30 , the invention is not limited to that and another wire rod beside the conductive line may be used. 
     As indicated by arrows c 1  through c 3  in  FIG. 22 , the weaving beginning portion of the weaving wire  116  is wound once around the outer peripheral surface of the circular arc projection  114   b  of the lower plate  104  from the lower side clockwise and then the weaving wire  116  is engaged with the first guide groove  122  (see  FIG. 3 ) of the circular arc projection  114   a  of the upper plate  102 . Because the circular arc projection  114   b  of the lower plate  104  is provided with a notch portion  136  formed so as to secure the weaving beginning portion of the weaving wire  116 , the notch portion  136  smoothly secures the weaving beginning portion of the weaving wire  116  at this time. 
     Next, the weaving wire  116  is woven sequentially along the first guide groove  122  of the circular arc projection  114   b  of the lower plate  104  and the first guide groove  122  of the circular arc projection  114   b  of the upper plate  102  that are disposed alternately along the peripheral direction so as not to be superimposed in the vertical direction as indicated by arrows c 4  through c 17  while reciprocating the nozzle  30  in the vertical direction in the state in which the upper and lower jigs  12  and  14  are rotated in a body along the peripheral direction under the driving action of the motor M. It is noted that the motor M is controlled by a controller not shown and is normally and inversely rotated appropriately to adequately tension the weaving wire  116  woven along the circular arc projections  114   a  and  114   b  of the upper and lower plates  102  and  104 . 
     Here, because the circular arc projection  114   a  of the upper plate  102  and the circular arc projection  114   b  of the lower plate  104 , i.e., the portions where the weaving wire  116  engages, are disposed alternately from each other in zigzag in the peripheral direction, it is possible to suitably prevent the upper and lower plates  102  and  104  from being dislocated with respect to the rotating direction thereof. 
     The weaving wire  116  woven between the upper and lower plates  102  and  104  extends substantially in parallel with the axial direction of the stacked coil  108 . Therefore, it is possible to obtain a good molded resin (see  FIG. 29A ) while maintaining the state of the stacked coil  108  held by the weaving wire  116  in molding the outer surface of the wound coil  100  by molten resin in a next process for example because the molten resin applies no excessive load to the weaving wire  116  by setting directions for filling the molten resin injected from gates of a die assembly described later. 
     After weaving the circular arc projections  114   a  and  114   b  of the upper and lower plates  102  and  104  by the weaving wire  116  alternately along the vertical direction, drawing the weaving wire  116  along the peripheral direction of the upper and lower plates  102  and  104  and winding the weaving wire  116  once around an outer peripheral surface of another circular arc projection clockwise as indicated by arrows c 18  through c 20 , the weaving ending portion of the weaving wire  116  is cut by the cutter means not shown. At this time, because the other circular arc projection of the lower plate  104  is provided with the notch portion  136  formed so as to secure the weaving ending portion of the weaving wire  116 , the notch portion  136  smoothly secures the weaving ending portion of the weaving wire  116 . 
     After constructing the wound coil  100  in which the weaving wire  116  is thus woven around the outer peripheral surfaces of the upper and lower plates  102  and  104 , the wound coil  100  is taken out by separating the upper jig  12  from the lower jig  14  by the elevation mechanism not shown and is conveyed to the next process. 
     Thus, according to the present embodiment, the wound coil  100  composed of the bobbinless coil may be formed readily and efficiently by holding the upper and lower plates  102  and  104  disposed separately by the predetermined distance by the upper and lower jigs  12  and  14  and by winding the wire rod  106  around the peripheral surface of the claw section  240  provided in the lower jig  14  (see a block E in  FIG. 30 ). 
     Further, according to the present embodiment, the isolation quality of the stacked coil  108  may be steadily secured by winding the winding beginning and ending portions of the stacked coil  108  exposed to the outside respectively to the first and second winding securing sections  110   a  and  110   b  separated in the left and right directions and by drawing those portions in cross by separating to the upper and lower surfaces of the plate portion  124 , in addition to that the isolation quality of the stacked coil  108  arrayed between the upper and lower plates  102  and  104  is suitably maintained. 
     In other words, the present embodiment allows the isolation quality to be steadily maintained by drawing the winding beginning portion of the stacked coil  108  along the under surface  104   b  of the plate portion  124  of the lower plate  104  made of resin via the second guide groove  126 , by drawing the winding ending portion of the stacked coil  108  so as to cross with the winding beginning portion along the upper surface  104   a  of the plate portion  124  of the lower plate  104  and by interposing the plate portion  124  made of a resin material between the winding beginning portion and the winding ending portion to keep a non-contact state. 
     While one embodiment of the invention has been described above, the invention is not limited to the embodiment described above and may be modified within a scope of the gist of the invention as follows for example. 
     Although the claw section  240  has been arranged to have the first through third split claws  241   a  through  241   c  in the embodiment described above, the number of split claws is not limited to be three and may be two or four or more. Still more, the number of the radial springs  251  and the thrust springs  265  may be adequately changed. 
     Although the arrangement in which the thrust spring  265  is a compression coil spring has been exemplified in the embodiment described above, it may be a rubber material formed by adequate rubber for example. The same applies also to the radial spring  251 . 
     Although the upper jig  12  has been provided with the tapered portion  220  and the lower jig  14  has been provided with the claw section  240  in the embodiment described above, the function of the upper jig  12  may be reversed with the function of the lower jig  14 . That is, the upper jig  12  may be provided with the claw section  240  and the lower jig  14  may be provided with the tapered portion  220 . 
     Next, a process of acquiring the molded coil by molding the wound coil  100  formed in the previously described process with the resin material will be explained below.  FIG. 23  is a schematic structural longitudinal section view of the die assembly for molding the wound coil and  FIG. 24  is a schematic structural longitudinal section view of the die assembly shown in  FIG. 23  that is clamped after loading the form-to-be-molded into a cavity of the assembly. 
     First, the coil-to-be-molded  300  whose outer surface, except of its inner surface, is to be coated (molded) by the resin material will be explained. As shown in  FIG. 29A , the coil-to-be-molded  300  has the wound coil  100  sandwiched between the first plate (the lower plate)  104  on an upper side in the figure and the second plate (the upper plate)  102  on a lower side in the figure respectively made of the resin material and having the coil stacked by the wire rod  106  into the plurality of levels, a terminal section  150  connected with the pair of winding securing sections  110   a  and  110   b  protruding in the radial outward direction of the first plate  104  and is electrically connected with the coil and the weaving wire  116  for holding the first and second plates  104  and  102  by weaving the circular arc projections  114   a  and  114   b  of the first and second plates  104  and the second plate  102  disposed distant by the predetermined distance in the vertical direction. 
     It is noted that the coil-to-be-molded  300  is arranged such that the lower plate  104  composing the wound coil  100  shown in  FIG. 1  becomes the first plate  104  on the upper side and the upper plate  102  becomes the second plate  102  on the lower side. That is, the coil-to-be-molded  300  is disposed such that the wound coil  100  is vertically turned over. Beside them, the same or corresponding structural elements will be explained below by denoting the same reference numerals. 
     The terminal section  150  has a terminal  152   a  electrically connected with the winding beginning portion of the wire rod  106  and a terminal  152   b  electrically connected with the winding ending portion of the wire rod  106 . Still more, no core material such as a coil bobbin is provided in the coil inner peripheral surface  120  of the wound coil  100  and the coil inner peripheral surface  120  is exposed to the outside. 
     The first plate  104  is provided with three projections  154  that project by a predetermined length in the radial outward direction from the coil outer peripheral surface  121  (see  FIG. 23 ) and are distant equiangularly along the peripheral direction between the neighboring circular arc projections  114   b . As shown in  FIG. 28 , each of these projections  154  functions as a molten resin receiving section positioned right under a terminal portion of each gate when the molten resin is injected into a cavity  430  from a plurality of gates of an upper die  412  as described below and promotes a flow of the molten resin so that the molten resin received by the projection  154  is filled into a thin portion molding airspace  444  described below. 
     As shown in  FIG. 23 , the die assembly  410  includes the upper die  412  liftably provided by a elevation mechanism not shown, a lower die  414  fixed on a base not shown and a pair of split dies  420   a  and  420   b  movably provided in the horizontal direction through a displacement mechanism not shown and provided with a projection that functions as a nesting for forming a hollow coupler section  502  described later (see  FIG. 29B ). It is noted that the pair of split dies  420   a  and  420   b  may be constructed in a body without splitting them. 
     Still more, the die assembly  410  has a first die member  424  fitted into a hole of the upper die  412  and having a ringed projection  422  bulgingly formed to butt the upper surface in a vicinity of an inner peripheral edge portion of the first plate  104  on the upper side and to press and seal the wound coil  100  downward, a second die member  428  fitted into a hole of the lower die  414  and having a ringed projection  426  bulgingly formed so as to face the under surface of the second plate  102  on the lower side to form a ringed groove (not shown) for seal-fitting to a bottom surface of the molded resin  500  (see  FIG. 29B ) and a core member  432  fitted into the second die member  428  for forming a cavity  430  between wall surfaces of the upper and lower dies  412  and  414  (see  FIG. 24 ). It is noted that the die assembly  410  is provided with a degassing passage not shown communicating with the cavity  430 . 
     The upper die  412  is provided with a plurality of gates connected to a molten resin supplier not shown including a plastic injection molding machine for example to discharge (inject) the molten resin to the cavity  430 . As shown in  FIG. 27 , the plurality of gates is disposed by being separated equiangularly in the peripheral direction of the wound coil  100  and includes first through third gates  434   a  through  434   c  that form a sealing resin  504  (see  FIG. 29B ) that coats the outer peripheral surface and the both end surfaces in the axial direction of the wound coil  100  and a fourth gate  434   d  that forms the coupler section  502  formed of a housing storing the first and second terminals  152   a  and  152   b.    
     Here, the first through third gates  434   a  through  434   c  are disposed at positions corresponding to the projections  154  of the upper die  412  i.e., right above or substantially right above the projections  154 , when the dies are clamped as shown in  FIGS. 24 and 27 . It is noted that  FIG. 27  is a plan view of the clamped die assembly  410  when seen from above and shows the projections  154  of the first plate  104  disposed within the cavity  430  by solid lines for convenience to clarify the positional relationship in the vertical direction between the first through third gates  434   a  through  434   c  and the projections  154  of the first plate  104 . 
     The lower die  414  is provided with a plurality of ejector pins  436  (see  FIG. 26 ) for taking out the molded resin  500  out of the cavity  430  by pressing the molded resin  500  whose molten resin is solidified upward. The ejector pins  436  are provided so as to be displaceable in the vertical direction by a driving action of an actuator not shown. 
     As shown in  FIG. 23 , the core member  432  is provided with a columnar section  438  that contacts the inner peripheral surface  160  of the first plate  104  and performs positioning and sealing functions with the inner peripheral surface  160  of the first plate  104 , a broad base portion  440  composed of a ringed enlarged portion that contacts the inner peripheral surface  162  of the second plate  102  and performs positioning and sealing functions with the inner peripheral surface  162  of the second plate  102  and a ringed stepped portion  439  formed closely to the second die member  428  under the broad base portion  440  to press the under surface in the vicinity of the curved portion of the second plate  102  upward. 
     A diameter (outer diameter) D 1  of the columnar section  438  of the core member  432  that faces to the coil inner peripheral surface  120  between the first plate  104  and the second plate  102  in the vertical direction is set to be smaller than an inner diameter D 2  of the coil inner peripheral surface  120  (D 1 &lt;D 2 ). Accordingly, when the coil-to-be-molded  300  is loaded into the cavity  430  and the die assembly is clamed, the core member  432  is kept in a non-contact state with the coil and a clearance  442  is created between the outer peripheral surface of the columnar section  438  of the core member  432  and the coil inner peripheral surface  120  as shown in  FIG. 24 . 
     It is noted that although the upper die  412  is provided liftably with respect to the lower die  414  in the present embodiment, the invention is not limited to that and it will do if the upper die  412  and the lower die  414  are provided relatively separably. 
     The die assembly  410  for carrying out the molding is constructed basically as described above. Next, its actions and effects will be explained. 
     At first, after loading the coil-to-be-molded  300  (see  FIG. 29A ) into the cavity  430  of the die assembly  410 , the upper die  412  and the first die member  424  are lowered in a body by means of the elevation mechanism not shown and the pair of split dies  420   a  and  420   b  are displaced by the displacement mechanism not shown to clamp the die assembly as shown in  FIG. 23 . 
     In the clamped state, the terminal portions  446  of the first through third gates  434   a  through  434   c  are positioned so as to correspond to the projections  154  of the first plate  104  in the vertical direction. That is, the terminal portions  446  of the first through third gates  434   a  through  434   c  come at the positions right above or substantially right above the projections  154 . Still more, in the clamped state described above, the ringed airspace for molding thin portion  444  whose vertical size is small and radial size is narrow is formed between a bottom wall of the upper die  412  and the upper surface of the first plate  104 . It is noted that the thin portion molding airspace  444  composes a part of the cavity  430  and forms a thin portion  512  that composes a bottom surface of a ringed concave portion  506  formed on an outer end surface (upper surface) of the molded resin  500  described later. 
     After claming the dies, the molten resin supplying source not shown is urged to inject the molten resin from the first through fourth gates  434   a  through  434   d  (see  FIG. 25 ). The molten resin discharged out of the terminal portions  446  of the first through third gates  434   a  through  434   c  is received by the projections  154  of the first plate  104  that function as the molten resin receiving sections, is promoted to flow into and to smoothly fill the thin portion molding airspace  444  formed between the bottom wall of the upper die  412  and the upper surface of the first plate  104  and is also flown downward along the cavity  430  formed between the outer peripheral surface of the coil-to-be-molded  300  and the side wall of the lower die  414  (see  FIG. 28 ). It is noted that a direction in which the molten resin is filled is supposed to be parallel with the axial direction of the wound coil  100  and to be gradually filled from the lower part to the upper part of the cavity  430 . 
     In other words, if no projection  154  is provided right under the terminal portions  446  of the first through third gates  434   a  through  434   c , there is nothing that receives the molten resin discharged out of the terminal portions  446  of the first through third gates  434   a  through  434   c , so that the molten resin flows only downward along the cavity  430 . Accordingly, the molten resin hardly flows into the thin portion molding airspace  444  that extends in the horizontal direction (the direction orthogonal to the discharge direction of the molten resin) from the terminal portions  446  of the first through third gates  434   a  through  434   c  and there is a possibility of causing short molding due to an insufficient amount of the molten resin to be filled into the thin portion molding airspace  444 . 
     However, because the projection  154  that functions as the molten resin receiving section is provided so as to project by the predetermined length in the radial outward direction at the outer periphery of the first plate  104  so that it is positioned right under each of the first through third gates  434   a  through  434   c  and the projection  154  changes the flow direction of the molten resin such that the molten resin can flow in the horizontal direction from the terminal portion  446  of each gate, the present embodiment can suitably prevent the short molding described above from occurring by smoothly filling the molten resin into the thin portion molding airspace  444 . 
     At this time, the ringed projection  422  of the first die member  424  butts the upper surface near the inner peripheral portion of the first plate  104  and presses down the coil-to-be-molded  300 , so that it may suitably prevents such a phenomena that the first and second plates  104  and  102  are lifted up from otherwise occurring when the molten resin is filled along the cavity  430 . 
     Further, the inner peripheral surface  160  of the first plate  104  contacts the outer peripheral surface of the columnar section  438  of the core member  432 , thus forming a first sealing section, and the inner peripheral surface  162  of the second plate  102  contacts the broad base portion  440  of the core member  432 , thus forming a second sealing section. Still more, because the first plate  104  on the upper side and the second plate  102  on the lower side are positioned respectively at predetermined positions by the columnar section  438  and the broad base portion  440  of the core member  432 , coaxiality (coaxial precision) of the coil-to-be-molded  300  is improved. Accordingly, when the molten resin is filled along the cavity  430 , the first and second sealing sections formed by the inner peripheral surfaces  160  and  162  of the first and second plates  104  and  102  suitably prevent the molten resin from entering the coil inner peripheral surface  120  and allow the molten resin to be filled favorably into the coil-to-be-molded  300  while assuring the coaxiality. 
     Still more, the clearance  442  is formed between the outer peripheral surface of the columnar section  438  of the core member  432  and the coil inner peripheral surface  120  as described above. As a result, the wire rod  106  stacked on the coil inner peripheral surface  120  is suitably protected without being damaged in loading into the cavity  430  or by the flow of the molten resin. 
     The sealing function may be improved further in the present embodiment in cooperation with the sealing action of the first sealing section by providing the first die member  424  having the ringed projection  422  that presses down the vicinity of the inner peripheral surface of the first plate  104 . The sealing function may be also improved further in the present embodiment in cooperation with the sealing action of the second sealing section by providing the ringed stepped portion  439  that presses up the under surface in the vicinity of the bend portion of the second plate  102  in the core member  432 . 
     When the molten resin is solidified after competing the injection of the molten resin into the cavity  430  from the first through fourth gates  434   a  through  434   d , the molded resin (molded coil)  500  in which the both end surfaces in the axial direction and the outer peripheral surface of the wound coil  100 , except of the coil inner peripheral surface  120 , are molded by the resin material is formed (see a block E 3  in  FIG. 30 ). Then, the molded resin  500  may be readily taken out of the cavity  430  of the die assembly  410  and may be transferred to a next step by raising the plurality of ejector pins  436  under the driving action of the actuator not shown and by pressing the molded resin  500  upward. 
     As shown in  FIG. 29B , the molded resin  500  is provided, at the upper surface thereof (the outer end surface along the axial direction), with a ringed concave portion  506  formed so as to attach a sealing member not shown and a plurality of traces of gates  510  having substantially a shape of a small circle are formed on a ringed convex edge portion  508  located in the radial outward direction from the ringed concave portion  506 . Accordingly, no gate trace is formed within the ringed concave portion  506  that becomes the sealing surface, so that the sealing surface composed of a flat surface having no irregularity exhibits the sealing function suitably. 
     In other words, the traces of gates  510  are formed on the outer peripheral side of the thin portion  512  of the molded resin  500  formed by the thin portion molding airspace  444  by disposing The first through third gates  434   a  through  4343  in the radial outward direction more than the thin portion molding airspace  444 . Accordingly, because no traces  510  are formed on the thin portion  512  that becomes the sealing surface, the sealing surface composed of the flat surface having no irregularity exhibits the sealing function suitably. 
     Still more, the thin portion  512  composing the bottom surface of the ringed concave portion  506  is formed on the outer side surface along the axial direction of the molded resin  500 . The thin portion  512  is formed by the molten resin filled into the thin portion molding airspace  444  that is a part of the cavity  430  is solidified, so that a good molded surface may be formed from which any short molding and sink are suitably prevented as described above. 
     It is noted that although the mode described above is the best mode for carrying out the invention, it is not intended to limit the invention to such mode. Accordingly, the mode for carrying out the invention may be variously modified within a scope in which the subject matter of the invention is not changed.