Abstract:
Using a single bobbin, this invention makes the respective turn counts of windings in an axial-air-gap rotating electric machine the same and minimizes the lengths of connecting wires between continuous windings regardless of the continuous turn count, the direction in which each winding is wound, and whether the number of stages is odd or even. The aforementioned bobbin, which has a tubular shape that substantially matches the exterior shape of a core, is provided with flanges that extend outwards from near the respective openings in the bobbin. One of said flanges has two first notches, and the other flange has at least one second notch. The axial positions of the starting ends and finishing ends of coils on adjacent stator cores are the same, and the flanges containing the notches through which the ends of said coils are run are on the same side with respect to the abovementioned openings.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to an axial-air-gap rotating electric machine, and more particularly to an axial-air-gap rotating electric machine provided with a stator bobbin (insulator). 
       BACKGROUND ART 
       [0002]    An axial-air-gap rotating electric machine has been attracting attention because it has a configuration effective for size reduction and efficiency improvement of a thin rotating electric machine. The rotating electric machine has a structure in which a tubular stator and a disk-shaped rotor are arranged so that the faces of the stator and the rotor face each other via a predetermined air gap in the rotation axis radial direction. Also, a member (core member) is known which is configured by a plurality of cores arranged in the circumferential direction, a coil wound around each of the cores, and a bobbin (insulator) which insulates between the cores and the coil. 
         [0003]    Here, the bobbin is formed by a tubular section having the coil wound therearound, and a flange located at each of both ends of the tubular section and protruding on the outer peripheral side. There are various techniques about the shape of the bobbin, because the shape of the bobbin greatly influences the characteristics and workability of the rotating electric machine. 
         [0004]    For example, Patent Literature 1 discloses an axial-air-gap motor having core members in each of which an insulator flange (flange) is provided with a notch groove for leading out the coil so that the coil is lead out from the notch groove to the periphery of the flange. 
         [0005]    Further, for example, Patent Literature 2 discloses an axial-air-gap motor in which insulators, each having a core mounted thereto, are arranged in series so that a coil is wound continuously around the insulators. The insulator of Patent Literature 2 is configured such that, in order to prevent that the coil is damaged by the edge of the core when, during the winding, the coil is extended over the core to the adjoining insulator, a thin plate-like rib is provided at the end surface of the outer peripheral surface of the core so that the edge and the coil are prevented from being brought into direct contact with each other. 
       CITATION LIST 
     Patent Literature 
     PATENT LITERATURE 1: JP-A-2008-118833 
     PATENT LITERATURE 2: JP-A-2007-14146 
     SUMMARY OF INVENTION 
     Technical Problem 
       [0006]    Meanwhile, in a rotating electric machine, there is a case where coils, each having a different wire diameter and a different number of turns, are arranged in the same coil arrangement spaces. In this case, the winding start position and the winding end position in the winding coil of even number stages are opposite to the winding start position and the winding end position in the winding coil of odd number stages in the winding axis. Further, when the same phase coils are arranged in series to be continuously wound, the distance between the continuous coils and the winding direction between the continuous coils are different according to the slot combination. 
         [0007]    In Patent Literature 1, a lead-out line section is provided at only one of the flanges (flange-shaped protruding portions) respectively provided at both ends of the insulator (bobbin). Therefore, when the winding end of a specific core member is located on the side opposite to the side of the lead-out line section, it is necessary that the coil be extended over the outer periphery of the adjacent core member coil and transferred to the lead-out line section. In this configuration, the cost loss and productivity are significantly affected by the extra crossover wire. 
         [0008]    It should be noted that, in Patent Literature 2, there is no disclosure about the lead-out line section of the coil which is lead out from each of the core members in the case where the core members are annularly arranged. 
         [0009]    There is desired a bobbin which can flexibly cope with the change in the winding specification, and can contribute to productivity improvement, cost reduction, and performance improvement. 
       Solution to Problem 
       [0010]    In order to solve the above-described problems, for example, the invention described in the claims is applied. That is, the invention provides an axial-air-gap rotating electric machine including: a stator configured by annularly arranging, about the rotation axis of the machine, a plurality of stator cores each including a core having an approximately columnar shape having end surfaces and an outer peripheral surface, a coil wound on the outer peripheral surface of the core, and a bobbin arranged between the core and the coil; and at least one rotor, a surface of which faces the end surface on each of the rotation axis radial directions via a predetermined air gap. The axial-air-gap rotating electric machine is characterized in that the bobbin is formed in a tubular shape having an inner peripheral shape approximately coincident with the outer peripheral shape of the core, and has a flange extended by a predetermined length to the outer peripheral side from the vicinity of each of both openings of the bobbin, in that one of the two flanges has two first notches, in that the other of the two flanges has at least a second notch, and in that the axial direction positions of the winding start and the winding end of the coil are the same between the stator cores adjacent to each other, and the flanges, each having the notch through which the coil is led out, are located on the same opening side. 
       Advantageous Effects of Invention 
       [0011]    The present invention provides the effect that, by using the same bobbin, it is possible that the number of turns of each of windings is the same, and the length of the crossover wire between the continuously wound wires is minimized, and the shortening of the manufacture period and the reduction of the manufacturing cost can be achieved without deteriorating the characteristics of the rotating electric machine and without regard to the winding specification change. 
         [0012]    Other objects and advantages of the invention will become apparent from the following description. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0013]      FIG. 1  is a perspective view showing a configuration of a main part of an armature of an axial-air-gap motor according to a first embodiment to which the present invention is applied. 
           [0014]      FIG. 2  is a perspective view showing individual characteristics of a bobbin according to the first embodiment. 
           [0015]      FIG. 3  is a view showing one end portion of the bobbin shown in  FIG. 2 . 
           [0016]      FIG. 4( a )  and  FIG. 4( b )  are schematic views each showing a connection state of a 10-pole 12-slot motor according to the first embodiment. 
           [0017]      FIG. 5( a )  is a schematic view showing a state of continuous winding of bobbins according to the first embodiment, and  FIG. 5( b )  is a schematic view showing a state of a coil crossover wire portion after coil winding. 
           [0018]      FIG. 6( a )  is a schematic view showing a state of another continuous winding of bobbins according to the first embodiment, and  FIG. 6( b )  is a schematic view showing a state of a coil crossover wire portion after coil winding. 
           [0019]      FIG. 7  is a perspective view showing the arrangement relationship of the stator and the housing according to a second embodiment. 
           [0020]      FIG. 8  is a perspective view showing a configuration of a stator core according to the second embodiment. 
           [0021]      FIG. 9  is a perspective view showing a configuration of the stator core (without conductive member) according to the second embodiment. 
           [0022]      FIG. 10  is a perspective view showing another configuration of the stator core (without conductive member) according to the second embodiment. 
           [0023]      FIG. 11( a )  is a sectional view of a stator of an 8-pole 12-slot motor as another embodiment of the present embodiment, and  FIG. 11( b )  is a schematic view showing the wiring relationship of the 8-pole 12-slot motor. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0024]    In the following, embodiments according to the present invention will be described with reference to the accompanying drawings. 
       First Embodiment 
       [0025]      FIG. 1  shows a main configuration of an armature portion of a double-rotor type axial-air-gap permanent magnet synchronous motor  1  (hereinafter simply referred to as “motor  1 ”) to which the present invention is applied. 
         [0026]    The motor  1  has a configuration in which a stator  19  having a plurality of stator cores  20  arranged annularly about a rotation axis, and two rotors  30  respectively having surfaces, which respectively face both axial-direction end surfaces of the stator  19 , are arranged via a predetermined air gap to be aligned in the rotation axis radial direction. The stator  19  is fixed to the inner peripheral surface of a housing  40  having a tubular-shaped inner tube. End brackets are connected respectively on both opening sides of the housing  40  to rotatably support a shaft (not shown) fixed to the rotor  30  via bearings (not shown). 
         [0027]    The stator core  20  is configured by at least a laminated core  21  having end surfaces of approximately trapezoidal shape or fan-shape, a bobbin  23  having an inner tubular shape approximately the same as the core  21 , and a coil  22  wound on the outer tubular portion of the bobbin  23 . The core  21  is obtained by laminating, in the axial diameter direction, thin plate-like members, each of which includes a magnetic body (amorphous in the present embodiment) and is cut to have the width increasing toward the housing side in the axial diameter. The core  21  may be a dust core and a cast core. 
         [0028]    It should be noted that, although not shown, the stator core  20  is molded integrally with the housing  40  by resin molding to be simultaneously fixed to the housing  40 . It should be noted that the stator cores  20  may also be configured such that the stators  40  are mutually connected in an annular shape to be fixed to the housing by bolts, or the like, or such that only the stators  20  are formed integrally with each other by resin molding to be fixed to the housing  40  by bolts. In the case where only the stator cores  20  are resin-molded, it can be expected that the strength and durability are improved. 
         [0029]    The rotor  30  is configured such that approximately fan-shaped permanent magnets  31  are arranged on a yoke  32  in the rotation direction so that the magnetic poles of the permanent magnets adjacent to each other are different from each other. It should be noted that, although a double-rotor type is exemplified in the present embodiment, the present invention is limited to this, and a single-rotor type, a triple-rotor type, or the like, may also be used. Further, a terminal box is provided at one of the side surfaces of the housing  40 , and the primary side electric wire and the secondary side wire are electrically connected to each other via the terminal block. The crossover wire led out from the winding  22  is connected to the secondary side wire. 
         [0030]      FIG. 2  and  FIG. 3  show a configuration of the bobbin  23 . As shown in  FIG. 2 , the bobbin  23  has a tubular section  23   a  around which the coil  22  is wound, and a flange  23   b  located at each of the ends of the tubular section  23   a  and protruded by a predetermined width to the outer peripheral side. In  FIG. 2 , first notches  10   a  and  10   b  are provided at the outer diameter side of the upper flange (the side of the housing  40 ), and a second notch  10   c  is provided at the outer diameter side of the lower flange. 
         [0031]    As shown by  FIG. 10 c   , it is preferable that the edge (inner edge corner) of each of the notches be chamfered. In the present embodiment, each of the flanges is formed so that the inner edge corner becomes a curvature radius R 11  which is large rather than the diameter of the coil. As shown in  FIG. 3 , each of the three notches is provided in the vicinity of the extension line from both ends of a bottom portion of the core  21  (approximately coincident with both ends of a bottom portion of the tubular section  23   a ) to the side of the housing  40 . In other words, the extension line is on the line obtained by projecting the core  21  from the notch  10   a,  and the like. More preferably, the outer side of the inner edge of each of the notches  10   a,    10   b  and  10   c  is located on each of the extension lines corresponding to the notches. This is because the coil  22  can be guided to a starting position without difficulty. 
         [0032]      FIG. 4( a )  and  FIG. 4( b )  schematically show a configuration of the coils of the motor  1 . Here, the description is given by taking as an example a 10-pole 12-slot 3-phase configuration. 
         [0033]    It is assumed that the coils  22  are connected as the delta connection having the two series and two parallel connection, and continuous windings of the same phase are connected in series. It should be noted that, as the winding method, there are two methods of an odd number of stages and of an even number of stages. Here, the plus and minus in each of the figures represent the winding directions of the coil. As shown in  FIG. 4( b ) , in the 10-pole 12-slot motor, windings of the same phase, which have different winding directions, are arranged adjacent to each other. Further, as shown in  FIG. 4( b ) , a delta connection, which is configured by connecting the six coils of U 1 + to W 1 − so that the windings of the same phase are connected in series, is connected in parallel with a delta connection, which is configured by connecting the six coils of U 2 − to W 2 + so that the windings of the same phase are connected in parallel. 
         [0034]    Next, the winding method of the coil  22  will be described.  FIG. 5  shows an example using the coil  22  having two wires in an odd number of winding stages. The two wires are connected in parallel at end portions. As compared with a coil having one wire, the coil having two wires has an advantage that the wire diameter can be reduced while maintaining the same direct-current resistance. Thereby, the influence of the skin effect of the wire is reduced, and hence, resistance to AC components can be reduced. Although not shown, the bobbin  23  is fixed to a winding jig at the time of winding. At this time, the flanges  23   b  whose notch shapes are the same are arranged so that the end surfaces of the flanges  23   b  face each other in the axial direction. That is, the bobbin is rolled in the winding direction in the state where the coil end on the left side in the figure is entwined and fixed to a winding jig, or the like. At the same time, a nozzle which supports the coil is moved in the horizontal direction so that the coil is wound around the tubular section of the coil. 
         [0035]    In the present embodiment, after the nozzle is reciprocated 2N−1 (N: integer) times between the flanges  23   c,  the coil  22  is made to pass through the notch  10   c,  and is then made to pass through the same notch  10   c  of the bobbin facing the bobbin on which the wire is wound. Thereafter, also for the right side bobbin, the coil  22  is wound by rotating the bobbin 2N−1 (N: integer) times, and then, the coil  22  is led out to the outside through the notch  10   b  corresponded with the winding start position. As shown in  FIG. 5( b ) , after the winding, a connecting wire  22   b  between the continuous windings is removed from the notch  10   c,  and then, the both bobbins are rotated so that the connecting wire  22   b  passes through the outer diameter side of the winding of the left side bobbin. Thereby, the continuous coils having different winding directions D are completed. 
         [0036]    Then,  FIG. 6( a )  and  FIG. 6( b )  shows an example using the coil  22  having two wires in an even number of winding stages. In this case, the bobbins  23  are arranged so that the flanges  23   b  each having two notches  10   a  and  10   b  face each other. In this state, the winding is started from the notch  10   b  of the left side bobbin in  FIG. 6( a ) . In the even number of winding stages, the nozzle supporting the coil is located on the winding start side when the last stage of winding is ended. Then, the winding is led out from the other notch  10   a  to the notch  10   a  of the adjacent bobbin, and the winding is performed similarly. After the winding, the coil  22  is removed from each of the notches  10   b,  and then, the bobbin is rotated so that the connecting wire  22   b  between the continuous windings passes through the outer periphery of the right side coil. Thereby, as shown in  FIG. 6( b ) , the continuous windings having different winding directions D are completed. 
         [0037]    According to the first embodiment, the continuous windings having different winding directions can be wound by using the same bobbins. In addition, at the time of an odd number of stages or at the time of an even number of stages, the winding can be performed by using the same bobbins. Further, the horizontal position in the rotation axis direction at each of the winding start and the winding end is the same for the coils  22  adjacent to each other, and the position at which the coil is led out from each of the stator cores  20  can also be the same as the position of each of the notches. 
         [0038]    It should be noted that, when the winding directions of the continuous windings are the same, the coil can be wound similarly by changing winding directions of the first and second bobbins. 
         [0039]    Further, the winding start and the winding end of the first bobbin are coincident with the winding start and the winding end of the second bobbin, and hence, the difference between the number of windings does not cause a problem. Therefore, electromagnetic imbalance due to the difference between the number of windings does not occur. The connecting wire  22   b  between the continuous windings can be formed to have a necessary minimum length by appropriately setting the distance between the flanges  23  of the bobbins facing each other. For this reason, there is no possibility that the resistance is increased by the extra connecting wire  22   c,  and also there is no possibility that the slackened connecting wire  22   c  becomes too close to the housing  40  and is short-circuited with the housing  40 . 
         [0040]    Further, each of the notches  10   a  to  10   c  is located on the extension line of each of the legs of the tubular section  23   a,  and hence, when the connecting wire  22   b  is pulled to the notches  10   a  to  10   c,  and the like, it is not necessary to forcibly deform the connecting wire  22   c.  In this regard, the same effect is obtained in the shape of the connecting wire between the continuous windings, which is obliquely pulled out in the figure. 
         [0041]    Further, since the edge of each of the notches  10   a  to  10   c  is chamfered into a curvature radius R 11 , it is suppressed that the coil is bent to have a curvature radius R smaller than the wire diameter, and it is suppressed that the insulating layer of the coil surface is damaged. Preferably, when the curvature radius R is set to about twice the wire diameter, it is possible to more sufficiently obtain the above-described effect. Further, the coil winding machine only needs to have: a one-axis rotating mechanism which rotates at least the bobbin; a nozzle mechanism which moves the coil in the horizontal direction; and a tension mechanism which applies tension to the coil when the coil is moved in the horizontal direction. Therefore, the winding is manufactured with a simple coil winding machine, and hence, the manufacturing cost can be reduced. 
       Second Embodiment 
       [0042]    As one of the features, the motor  1  according to the second embodiment includes a conductive member  50  on the bobbin flange  23   c.  In the following, the second embodiment is described with reference to the accompanying drawings, but portions that are the same as those in the first embodiment are denoted by the same reference numerals and characters, and the explanation thereof is omitted. 
         [0043]      FIG. 7  shows a state where the stator  19 , which is configured by the stator cores  20  each having the conductive member  50  arranged at the flange  23   c,  is arranged in the housing  40 . As shown in  FIG. 8 , the conductive member is arranged on the flange  23   c  and on the side of the housing  40 , and is formed by a members, such as metal, which has a platy shape. The end portion of the conductive member  50  in the direction of rotation about the rotation axis has a length longer than the housing side length of the flange  23   c  and protrudes from the flange  23   c.  An opening  50   a  is provided in the protruding portion of the conductive member  50 . The conductive member  50  is configured such that the opening  50   a  of one end portion of the conductive member of the stator core  20 , and the opening  50   a  of one end portion of the conductive member of the adjacent stator core  20  can be connected to each other by a fastening members  60 , such as a rivet. It should be noted that the conductive members  50  may be in a structural relationship such that a concave portion of the conductive member of the stator core  20 , and a convex portion of the conductive member of the adjacent stator core  20  are connected to each other by adhesion, or the like. 
         [0044]    Further, as shown in the figures, the conductive member is configured to be in contact with the housing-side outer peripheral surface of the core  21  whose top portion protrudes from the bobbin  23 , and is configured such that the end surface of the conductive member, which surface is located on the side opposite to the contact surface, is in contact with the inner peripheral surface of the housing  40 . Therefore, the conductive member has a function that the electrostatic capacitance between the rotor  30  and the stator  19  with respect to ground is reduced, and thereby, the shaft voltage around the bearings is reduced to prevent the electrolytic corrosion of the shaft. Further, the conductive member also functions as a plate for cooling the core, and the like. 
         [0045]    Further, the conductive member is configured to have notches  50   b  at (two) portions thereof which respectively face the notches  10   a,    10   b  and  10   c  of the bobbin  23 , and is configured such that the conductive member does not cover the notch  10   a,  and the like, when being placed on the flange  23   c.    
         [0046]      FIG. 9  shows a state where the conductive member  50  is removed from the stator core  20  of the second embodiment. In the second embodiment, the inner edge of each of the notches  10   a  to  10   e  of the flange  23  of the bobbin has a protruding section  50   c  extending by a predetermined distance in the axial direction A. The protruding section  50   c  is formed such that the outer periphery of the protruding section  50   c  is fitted with the inner edge of the notch  50  of the conductive member. 
         [0047]    According to the second embodiment, the conductive member  50  is fitted to the protruding section  12  of the bobbin  23 , and the twelve conductive members are fastened to the bobbin  23 , to thereby position the bobbin  23 . That is, since the bobbin  23  is firmly fixed in the circumferential direction and the radial direction, it is possible that the bobbin  23  is positionally displaced by the injection pressure of the resin when the bobbin  23  is integrally formed by resin molding. Further, the conductive member  50  has thermal conductivity several tens to several thousand times the resin material, and hence also contributes to the cooling. 
         [0048]    Further, since the inner edge of the notch  10   a,  and the like, of the bobbin  23  is protruded in the rotation axis direction, the curvature radius R 11  of the corner portion, which is formed between the side surface of the notch  10 , and the like, and the bottom surface of the flange  23   c,  which surface faces the coil, can be increased, and also, the thickness of the flange can be reduced (for example, the thickness of about ½ of the curvature radius R 11 ). When the thickness of the flange  23   c  is reduced, the axial direction length of the stator core  20  can be reduced. Generally, in the axial-air-gap rotating electric machine, the reduction of the axial direction length of the core reduces the magnetic resistance and loss, and thereby, the motor characteristics are improved. Also, the reduction of the axial direction length of the core reduces the material cost. The protruding section  50   b  also contributes to securing the creepage distance between the conductive member  50  and the connecting wire  22   b.    
         [0049]    It should be noted that the second embodiment shows an example in which the protruding section of the inner edge of the notch  10   a,  and the like, is fitted with the notch of the conductive member  50 , but another mechanism having a function of positioning these may also be provided. For example, a tubular protruding section may be provided between the notches  10   a,  and the like, so that an opening of the conductive member  50 , which opening is provided to correspond to the tubular protruding section, is positioned with the tubular protruding section. 
         [0050]    Further, the shape of the notch of the bobbin flange  23   c  may be another shape. 
         [0051]      FIG. 10  shows a shape in which the notch of the flange  23   a  is divided into two regions by a partition section  13 . When the notch  10   a,  or the like, is formed to correspond to the number of wires of the coil in this way, the alignment of the coil  22  can be easily secured, so that the workability is improved. 
         [0052]    [Manufacturing Method of Bobbin] 
         [0053]    The bobbin  23   c  of the present embodiment is formed by insulating resin and is manufactured by resin molding. However, the present invention is not limited to this, and the bobbin can also be manufactured by a three-dimensional modeling machine, or the like, as described below. That is, the bobbin  23  can be obtained not only by the method in which the bobbin itself is manufactured by the three-dimensional modeling machine, but also by the method in which a metallic mold for resin molding is formed by laminate molding with the three-dimensional modeling machine or by cutting processing with a cutting RP apparatus. 
         [0054]    As the laminate molding, it is possible to apply an optical modeling method, a selective laser sintering method, an ink jet method, a resin dissolution lamination method, a gypsum powder method, a sheet forming method, a film transfer image lamination method, a metal optical shaping composite processing method, and the like. 
         [0055]    The data for the laminate molding or the cutting processing is generated in such a manner that 3D data generated by CAD, CG software, a 3D scanner, or the like, is processed into NC data by CAM. The data are inputted into the three-dimensional modeling machine or the cutting RP apparatus, and thereby, 3D modeling is performed. It should be noted that NC data may be generated directly from 3D data by CAD/CAM software. 
         [0056]    Further, the bobbin  23  and a resin injection molding mold for the bobbin  23  can be manufactured by a method in which a data provider or a servicer, which has created 3D data or NC data, can delivered, via a communication lines, such as the Internet, the 3D data or NC data converted into a predetermined file format, and in which a user downloads the delivered data to a 3D modeling machine, a computer controlling the 3D modeling machine, or the like, or accesses the data as cloud-based services, and thereby, the 3D modeling machine performs the shaping and outputs the result of the shaping to manufacture the bobbin  7 . It should be noted that the method, in which the data provider records the 3D data or the NC data in a nonvolatile recording medium to provide the data to the user, can also be used. 
         [0057]    An aspect of the manufacturing method of the bobbin  23  according to the present embodiment as described above provides a manufacturing method of a bobbin arranged between a core having an approximately columnar shape having end surfaces and an outer peripheral surface, and a coil wound around the outer peripheral surface of the core. The manufacturing method is characterized in that the bobbin is manufactured by the 3D modeling machine on the basis of the three dimensional data, the bobbin including: an inner tubular portion having an inner peripheral shape approximately coincident with the outer peripheral shape of the core; an outer tubular portion around which the coil is wound; and a flange which is extended, by a predetermined length, from the vicinity of each of both openings of the outer tubular portion in the direction perpendicular to the tubular portion, and which includes two first notches provided on one side of the flange, and at least a second notch provided on the other side of the flange and facing one of the first notches. 
         [0058]    Further, another aspect of the manufacturing method of the bobbin  23  as described above provides a manufacturing method of a bobbin arranged between a core having an approximately columnar shape having an end surface and an outer peripheral surface, and a coil wound around the outer peripheral surface. The manufacturing method is characterized in that data for the three-dimensional modeling machine for manufacturing the bobbin are transmitted and delivered via a communication line, the bobbin including: an inner tubular portion having an inner peripheral shape approximately coincident with the outer peripheral shape of the core; an outer tubular portion around which the coil is wound; and a flange which is extended, by a predetermined length, from the vicinity of each of both openings of the outer tubular portion in the direction perpendicular to the tubular portion, and which includes two first notches provided on one side of the flange, and at least a second notch provided on the other side of the flange and facing one of the first notches. 
         [0059]    In the above, the embodiments for carrying out the present invention are described, but the present invention is not limited to these. For example, each of the above-described embodiments is configured such that the flange  23   b  has the notches at two places on the same surface, and the winding is lead out from one of the notches. Thereby, the notch, at which the connecting wire  22   b  is not provided, is formed at one place of each of the upper and lower flanges  23   b.  Thereby, a path, through which resin is moved in the axial direction at the time of resin molding, can be formed. A resin injection port can be provided at this position. 
         [0060]    Further, in the embodiments, the double-rotor type axial-air-gap motor is used as an example, but a synchronous reluctance motor, a switched reluctance motor, an induction motor, or the like, in each of which no permanent magnet is provided, may also be used. Further, other the motor, a generator may also be used. Further, in the rotor, a back yoke may be provided between the permanent magnet and the yoke. 
         [0061]    The winding specifications are not limited to those described above.  FIGS. 11( a ) and 11( b )  show a connection diagram assuming an 8-pole 12-slot motor. Here, an example is shown in which three windings, each formed by connecting four coils in series, are star-connected. In this case, the winding directions of all the coils are the same. Therefore, the four continuous coils can be manufactured in such a manner that four bobbins are arranges in series in the axial direction, and that the winding direction of the coil is alternately reversed. The number of wires of the coil can be arbitrarily set. 
         [0062]    The shape of the notch is also not limited to the present embodiments. As described above, it is only necessary that at least three notches be provided, and three or more notches may also be provided. Further, in the present embodiments, the shape of the notch is the rectangular shape parallel to the lower base of the trapezoidal shaped core, but the shape of the notch may also be a rectangular shape, a trapezoidal shape, a semicircular state, or the like, which are parallel to the radial direction. 
       REFERENCE SIGNS LIST 
       [0063]      1  Double-rotor type axial-air-gap permanent magnet synchronous motor 
         10   a,    10   b,    10   c,  and  10   d  Notch 
       [0064]      11  Curvature radius R 
         19  Stator 
       [0065]      20  Stator core 
         21  Core 
       22  Coil 
       [0066]      22   a  Lead-out section
   22   b  Connecting wire
 
         23  Bobbin 
       [0067]      23   a  Cylindrical section 
         23   b  Flange 
       30  Rotor 
       [0068]      31  Permanent magnet 
         32  Yoke 
       40  Housing 
       [0069]      50  Conductive member 
         50   a  Opening 
       50   b  Notch 
       [0070]      50   c  Step portion
   60  Fastening member
 
D Winding direction