Patent Publication Number: US-2020287436-A1

Title: Armature

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application is based on Japanese Patent Application No. 2019-39285 filed on Mar. 5, 2019, the disclosure of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to an armature. 
     BACKGROUND 
     Conventionally, in a stator that is an armature of a motor, a core constituent member includes a tooth extending inward in a radial direction and a pair of core outer extension portions extending in a circumferential direction from an outer end in the radial direction of the teeth. A plurality of core constituent members are arranged side by side in a circumferential direction. Coils are wound around the tooth via an insulator. 
     SUMMARY 
     An object of the present disclosure is to provide an armature in which the position of the innermost diameter of the coil can be arranged on the outer side relative to the inner side in the radial direction. 
     The armature includes a wound member and a coil wound around the wound portion. The wound member includes a wound portion extending in a radial direction and a pair of outer extension portions extending from an outer end in the radial direction of the wound portion to both sides in a circumferential direction. On an inner side in the radial direction of a base portion of the outer extension portions, a concave portion is recessed radially outward from a winding outermost diameter position. The winding outermost diameter position is a virtual straight line that contacts radially inner ends at circumferential tip ends of the pair of outer extension portions when viewed from the axial direction. A first layer of the coil includes a first coil, a center of which is positioned radially inward from the winding outermost diameter position and in a range between 0.5 times a coil wire diameter and 1.5 times the coil wire diameter with respect to the winding outermost diameter position, and a second coil, at least a part of which is disposed in the concave portion on the radially outer side of the first coil. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic configuration diagram of an electric brake system including a motor according to an embodiment; 
         FIG. 2  is a schematic plan view of a stator in the same embodiment; 
         FIG. 3  is a perspective view of the stator in the same embodiment; 
         FIG. 4  is a perspective view of a core unit of the stator in the same embodiment; 
         FIG. 5  is a plan view of the core unit of the stator in the same embodiment; and 
         FIG. 6  is a partial plan view of the core unit of the stator in the same embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, an embodiment of a motor including a stator as an armature will be described with reference to the drawings. In the drawings, for convenience of explanation, part of the configuration may be shown exaggerated or simplified. Also, the dimensional ratio of each part may be different from the actual one. 
     As shown in  FIG. 1 , a motor  10  is used for an electric brake system. The electric brake system includes a hydro unit  11  that adjusts a hydraulic pressure of a brake fluid, the motor  10  that is connected to the hydro unit  11  and drives the hydro unit  11 , and an EDU (ELECTRIC DRIVER UNIT)  12  that controls a drive of the motor  10 . In the brake system of the present embodiment, the hydro unit  11  is interposed between the EDU  12  and the motor  10 . The motor  10  and the EDU  12  are electrically connected through a through hole  11   b  provided in a housing  11   a  of the hydro unit  11 . 
     The motor  10  of the present embodiment includes a rotor  20  and a stator  30 . 
     As shown in  FIG. 1 , the rotor  20  is provided on an inner side in a radial direction of the stator  30 , and has a rotor core  21 , magnets (not shown) provided on the rotor core  21 , and a rotation shaft  22  provided at the radial center of the rotor core  21 . One end in the axial direction of the rotation shaft  22  is directly or indirectly connected to a gear  11   c  in the hydro unit  11 . As a result, when the rotation shaft  22  is rotationally driven, the gear  11   c  in the hydro unit  11  is driven to adjust the hydraulic pressure of the brake fluid. 
     As shown in  FIGS. 2 and 3 , the stator  30  includes a stator core  31 , an insulator  32  (not shown in  FIG. 2 ) of the stator core  31 , and coils  33 . The stator core  31  has a substantially annular portion  31   a  and a plurality of teeth  31   b  extending radially inward from the annular portion  31   a . In the present embodiment, for example, twelve teeth  31   b  are provided. The coils  33  are wound around each of teeth  31   b  with the insulator  32  located in therebetween. The coils  33  are wound in, for example, a concentrated manner. 
     The coils  33  include a first three-phase winding  40  which is electrically connected to a first inverter circuit  12   a  provided in the EDU  12 , and a second three-phase winding  50  which is electrically connected to a second inverter circuit  12   b  provided in the EDU  12 . That is, in the present embodiment, first and second inverter circuits  12   a  and  12   b  constituting two systems (plurality of systems) in EDU  12  are provided, and the first and second inverter circuits  12   a  and  12   b  are supplied current to each of the three-phase windings  40  and  50 . 
     As shown in  FIG. 2 , the first three-phase winding  40  has a plurality of three-phase windings  41   a  to  41   f  to which a three-phase alternating current having a phase difference of 120 degrees is supplied from the first inverter circuit  12   a . The plurality of three-phase windings  41   a  to  41   f  includes U+phase winding  41   a , U-phase winding  41   b , V+phase winding  41   c , V-phase winding  41   d , W+phase winding  41   e , and W-phase winding  41   f.    
     As shown in  FIG. 2 , the second three-phase winding  50  has a plurality of three-phase windings  51   a  to  51   f  to which a three-phase alternating current having a phase difference of 120 degrees is supplied from the second inverter circuit  12   b . The plurality of three-phase windings  51   a  to  51   f  include X+phase winding  51   a , X-phase winding  51   b , Y+phase winding  51   c , Y-phase winding  51   d , Z+phase winding  51   e , and Z-phase winding  51   f.    
     The coil  33  of the present embodiment is wound, for example, in the order of W-phase winding  41   f , V+phase winding  41   c , Y+phase winding  51   c , X-phase winding  51   b , U-phase winding  41   b , W+phase winding  41   e , Z+phase winding  51   e , Y-phase winding  51   d , V-phase winding  41   d , U+phase winding  41   a , X+phase winding  51   a , Z-phase winding  51   f , for each tooth  31   b . Thus, all the coils  33  of the present embodiment have different phases from the coils  33  adjacent in the circumferential direction. 
     Here, the winding directions in which the U+phase winding  41   a  and the U-phase winding  41   b  are wound around the teeth  31   b  are the same. The winding directions in which the V+phase winding  41   c  and the V-phase winding  41   d  are wound around the teeth  31   b  are the same. Further, the winding directions in which the W+phase winding  41   e  and the W-phase winding  41   f  are wound around the teeth  31   b  are the same. The U+phase winding  41   a  and the U-phase winding  41   b  are wound around teeth  31   b  provided at positions different by 150 degrees in the circumferential direction. The V+phase winding  41   c  and the V-phase winding  41   d  are wound around teeth  31   b  provided at positions different by 150 degrees in the circumferential direction. The teeth  31   b  around the W+phase winding  41   e  is wound and the teeth  31   b  around the W-phase winding  41   f  is wound are provided at positions different by 150 degrees in the circumferential direction. 
     Furthermore, the winding directions in which the X+phase winding  51   a  and the X-phase winding  51   b  are wound around the teeth  31   b  are the same. The winding directions in which the Y+phase winding  51   c  and the Y-phase winding  51   d  are wound around the teeth  31   b  are the same. Further, the winding directions in which the Z+phase winding  51   e  and the Z-phase winding  51   f  are wound around the teeth  31   b  are the same. The teeth  31   b  around the X+phase winding  51   a  is wound and the teeth  31   b  around the X-phase winding  51   b  is wound are provided at positions different by 150 degrees in the circumferential direction. The teeth  31   b  around which the Y+phase winding  51   c  is wound and the teeth  31   b  around which the Y-phase winding  51   d  is wound are provided at positions different by 150 degrees in the circumferential direction. The teeth  31   b  around the Z+phase winding  51   e  is wound and the teeth  31   b  around the Z-phase winding  51   f  is wound are provided at positions different by 150 degrees in the circumferential direction. 
     The U+phase winding  41   a  and the U-phase winding  41   b  are connected by a jumper wire  41   g . The V+phase winding  41   c  and the V-phase winding  41   d  are connected by a jumper wire  41   h . The W+phase winding  41   e  and the W-phase winding  41   f  are connected by a jumper wire  41   j . The X+phase winding  51   a  and the X-phase winding  51   b  are connected by a jumper wire  51   g . The Y+phase winding  51   c  and the Y-phase winding  51   d  are connected by a jumper wire  51   h . The Z+phase winding  51   e  and the Z-phase winding  51   f  are connected by a jumper wire  51   j . The jumper wires  41   g ,  41   h ,  41   j ,  51   g ,  51   h ,  51   j  are provided on the other end side in the axial direction of the stator core  31  and on the side not facing the hydro unit  11  (lower side in  FIG. 1 ). As shown schematically in  FIG. 2 , those jumper wires are provided by being guided by a guide portion  32   a  (see  FIG. 4 ) to be described later connecting the insulators  32 . The jumper wire  41   j  connecting the W+phase winding  41   e  and the W-phase winding  41   f  and the jumper wire  51   j  connecting the Z+phase winding  51   e  and the Z-phase winding  51   f  are routed outward in the radial direction with respect to the other jumper wires  41   g ,  41   h ,  51   g ,  51   h , and thus are longer than the other jumper wires  41   g ,  41   h ,  51   g ,  51   h.    
     The first three-phase winding  40  of the present embodiment is connected to the first inverter circuit  12   a  by a delta connection. The second three-phase winding  50  is connected to the second inverter circuit  12   b  by a delta connection. 
     More specifically, a terminal line  33   a  of the U+phase winding  41   a  is connected to an U terminal of the first inverter circuit  12   a  together with a terminal line  33   a  of the W-phase winding  41   f . A terminal line  33   a  of the U-phase winding  41   b  is connected to a V terminal of the first inverter circuit  12   a  together with a terminal line  33   a  of the V+phase winding  41   c . A terminal line  33   a  of the W+phase winding  41   e  is connected to a W terminal of the first inverter circuit  12   a  together with a terminal line  33   a  of the V-phase winding  41   d.    
     A terminal line  33   a  of the X+phase winding  51   a  is connected to a X terminal of the second inverter circuit  12   b  together with a terminal line  33   a  of the Z-phase winding  51   f . A terminal line  33   a  of the X-phase winding  51   b  is connected to a Y terminal of the second inverter circuit  12   b  together with a terminal line  33   a  of the Y+phase winding  51   c . A terminal line  33   a  of the Z+phase winding  51   e  is connected to a Z terminal of the second inverter circuit  12   b  together with a terminal line  33   a  of the Y-phase winding  51   d . In addition, the jumper wires  41   g ,  41   h ,  41   j ,  51   g ,  51   h ,  51   j  connect the ends of the coil  33  on the opposite side to the above terminal line  33   a  for each phase. 
     As shown in  FIG. 1 , in the stator  30 , a guide member  60  is provided on the side of the hydro unit  11 , which is one side in the axial direction of the stator core  31 . 
     The guide member  60  guides the terminal lines  33   a  of the coils  33  which is drawn from the coil  33  to one side in the axial direction, and further guides them to the EDU  12 . The guide member  60  includes a guide body  61  and a pullout guide  62  for pulling out. 
     As shown in  FIG. 3 , the guide body  61  is formed in a substantially disk shape having a plurality of steps in the axial direction, and includes a plurality of notches  63  extending from the radially outer side to the radially inner side and penetrating in the axial direction. The terminal line  33   a  of the coil  33  passes through the notch  63  in the axial direction, is led out to one side in the axial direction of the guide body  61 , is bent in the circumferential direction, and extends along the step of the guide body  61 . The terminal line  33   a  is guided in the circumferential direction up to a part of the guide body  61  in the circumferential direction. 
     A pullout guide  62  is configured to have a long column shape in the axial direction, and is fixed to a part in the circumferential direction of the guide body  61 . Then, the terminal lines  33   a  guided to a part in the circumferential direction of the guide body  61  passes through an inside of the pullout guide  62  and is led out to one side in the axial direction. As described above, the terminal lines  33   a  are connected to the first and second inverter circuits  12   a ,  12   b.    
     Here, the stator core  31  of the present embodiment has a configuration in which the annular portion  31   a  is divided for each tooth  31   b . The core constituent member  31   d  includes a tooth  31   b  extending radially inward and a pair of core outer extension portions  31   c  extending circumferentially from radially outer ends on both sides of the tooth  31   b . A plurality of the core constituent members  31   d  are arranged side by side in the circumferential direction. Specifically, in the present embodiment, the core outer extension portions  31   c  of the twelve core constituent members  31   d  are arranged in the circumferential direction so as to form an annular shape, and the core outer extension portions  31   c  adjacent to each other in the circumferential direction are welded to form the stator core  31 . 
     Further, as shown in  FIGS. 5 and 6 , in the teeth  31   b  of the present embodiment, a width of a tip portion around which the coil  33  is not wound and a width of an intermediate portion around which the coil  33  is wound, as viewed from the axial direction, are the same. The width of the tip portion is set so as not to be larger than the width of the intermediate portion. Further, the core outer extension portion  31   c  is formed in an arc shape on both the radially outer surface and the radially inner surface when viewed from the axial direction. The coils  33  are wound around the teeth  31   b  via the insulator  32  in a state before the core constituent members  31   d  are arranged side by side in the circumferential direction. 
     As shown in  FIG. 4 , the insulator  32  of the present embodiment includes a first insulator  71  which is assembled from one axial side of the core constituent member  31   d  (the lower side in  FIG. 4 ), and a second insulator  72  which is assembled from the other axial side of the core constituent member  31   d  (the upper side in  FIG. 4 ). A pair of second insulators  72  are connected to each other by the guide portion  32   a , the second insulators  72  constitute a connecting insulator member  73 . The guide portion  32   a  connects the second insulators  72  separated by 150 degrees in the circumferential direction. The guide portion  32   a  includes inner extension parts  73   a  extending from a radially inner side of the second insulator  72  to an inner side in the radial direction, and an arc connection part  73   b  connecting the inner extension parts  73   a . The arc connection part  73   b  is formed in an arc shape when viewed from the axial direction. An arc wall part  73   c  protruding in the axial direction is formed on the radially inner side of the arc connection part  73   b , and the jumper wires  41   g ,  41   h ,  41   j ,  51   g ,  51   h ,  51   j  are guided along an outer surface in the radial direction of the arc wall part  73   c . As shown in  FIGS. 4 and 5 , one core unit  74  having two sets of core constituent members  31   d  separated by 150 degrees. The stator  30  of the present embodiment has three core units  74 , and the positions of the guide portions  32   a  of the respective core units are slightly shifted in the axial direction and in the radial direction so that the guide portions  32   a  do not collide with each other when the core units  74  are assembled (not shown). 
     The insulator  32  that corresponds to the first insulator  71  and the second insulator  72  has a tooth covering portion  32   b . The tooth covering portion  32   b  covers an axial end surface of the tooth  31   b  and a part of a circumferential end surface that is bent from the axial end surface. The insulator  32  has an outer covering portion  32   c  that extends from the radially outer side of the tooth covering portion  32   b  so as to cover a radially inner side surface and a part of an axial end surface of the core outer extension portion  31   c.    
     In the present embodiment, the tooth  31   b  and the tooth covering portion  32   b  extending in the radial direction constitute a wound portion  75  around which the coil  33  is wound. The core outer extension portion  31   c  and the outer covering portion  32   c  constitute a pair of outer extension portions  76  which extends from the radially outer end of the wound portion  75  in both the circumferential directions. The wound portion  75  and the outer extension portion  76  constitute a wound member  77 . 
     As shown in  FIG. 6 , a winding outermost diameter position A 1  is a virtual straight line that contacts the radially inner ends at circumferential tip ends of the pair of outer extension portions  76  when viewed from the axial direction. On an inner side in the radial direction of a base portion of the outer extension portions  76 , a concave portion  78  is recessed radially outward from the winding outermost diameter position A 1 . In the present embodiment, the coil  33  is wound so as to turn around the wound portion  75  by using a flyer device (not shown) that moves circularly. Therefore, a position where the wire S can be guided by using the flyer device is radially inward from the winding outermost diameter position A 1 , which is a position where the wire S does not collide with the outer extension portion  76 . The core outer extension portion  31   c  of the present embodiment has a radially inner surface formed in an arc shape when viewed from the axial direction, and the outer covering portion  32   c  has covered the radially inner surface with uniform thickness. Therefore, a concave portion  78  is provided on the radially inner side at the base portion of the outer extension portion  76  so as to be recessed radially outward from the winding outermost diameter position A 1 . 
     A first layer of the coil  33  wound so as to be in direct contact with the wound portion  75  includes a first coil  79 . A center B of the first coil  79  is positioned radially inward from the winding outermost diameter position A 1  and in a range between 0.5 times a coil wire diameter L and 1.5 times the coil wire diameter L with respect to the winding outermost diameter position A 1 . In other words, the first coil  79  has a radially outer position that is radially inner than the winding outermost diameter position A 1  and the first coil  79  is disposed radially outward from a position separated from the winding outermost diameter position A 1  by the coil wire diameter L. That is, a radial position A 2  of the center B of the first coil  79  is set so that a distance from the winding outermost diameter position A 1  to the radial position A 2  is larger than 0.5 times the coil wire diameter L and smaller than 1.5 times the coil wire diameter L. Specifically, the center B of the first coil  79  of the present embodiment is disposed radially inward from the winding outermost diameter position A 1  by about 0.8 times the coil wire diameter L. The first layer of the coil  33  has a second coil  80  partially disposed in the concave portion  78  on the radially outer side of the first coil  79 . 
     The insulator  32  includes a first convex portion  81  that restricts the movement of the first coil  79  inward in the radial direction. The first convex portion  81  is formed such that a radial width gradually decreases toward a top, and the top is curved. The protruding amount of the first convex portion  81  is set to about ⅕ of the coil wire diameter L. The insulator  32  includes a second convex portion  82  that restricts the movement of the first coil  79  outward in the radial direction. The second convex portion  82  is formed such that a radial width gradually decreases toward a top, and the top is curved. The protruding amount of the first convex portion  81  is set to about ⅕ of the coil wire diameter L. Further, a position of the top of the second convex portion  82  is arranged radially inside the winding outermost diameter position A 1  and within 0.5 times the coil wire diameter L. That is, a radial position A 3  of the top of the second convex portion  82  is set so that a distance from the winding outermost diameter position A 1  to the radial portion A 3  is smaller than 0.5 times the coil wire diameter L. 
     Thereby, the coil  33  is wound from the radial inside of the wound portion  75  by using the flyer device. When the first coil  79  is wound, if the coil  33  is wound substantially along the winding outermost diameter position A 1 , the coil  33  is guided to the top of the second convex portion  82 . Therefore, since the center B of the first coil  79  is larger than 0.5 times the coil wire diameter L, the first coil  79  is disposed radially inward from the winding outermost diameter position A 1 . Further, after the first coil  79  is wound, the second coil  80  is wound along the winding outermost diameter position A 1 . The second coil  80  is guided to the outer peripheral surface of the first coil  79 , and the second coil  80  is disposed outside the first coil  79  in the radial direction and in the concave portion  78 . In  FIG. 6 , when the coil  33  is wound along the winding outermost diameter position A 1 , the position of the wire S of the coil  33  is indicated by a two-dot chain line. 
     Further, as shown in  FIG. 5 , the coil  33  of the present embodiment is continuously wound around a pair of wound portions  75  connected by the guide portion  32   a  of the connecting insulator member  73 . A winding start of the coil  33  is set on the radially inner side of the wound portion  75 , and the winding start constitutes the terminal line  33   a  drawn from the radially inner side of the coil  33  to one side in the axial direction. As described above, the coil  33  includes a terminal inner coil  83  in which the terminal line  33   a  is drawn from the radially inner side to one side in the axial direction. 
     The insulator  32  covers the teeth  31   b  that are circumferentially adjacent to the teeth  31   b  around which the terminal inner coil  83  is wound, and the insulator  32  has a restriction portion  84  that restricts the movement of the terminal line  33   a  of the terminal inner coil  83 . 
     Specifically, as shown in  FIG. 6 , first, the insulator  32  that covers the tooth  31   b  around which the terminal inner coil  83  is wound has a radial direction restriction portion  85  that restricts the radial movement of the terminal line  33   a  of the terminal inner coil  83 . A pair of the radial direction restriction portions  85  are provided in the radial direction, and are formed so as to protrude in the direction orthogonal to the radial direction and open in the same direction when viewed from the axial direction. In the radial direction restriction portion  85 , the wire S of the coil  33  can be inserted into the inside of the radial direction restriction portion  85  from the direction orthogonal to the radial direction, and the wire S is disposed inside by the flyer device. In addition, an opening part of the radial direction restriction portion  85  of the present embodiment is formed so that a width of the opening part is slightly smaller than the coil wire diameter L, and the wire S becomes difficult to come off, when the wire S is inserted in the inside. The restriction portion  84  is formed to protrude from the insulator  32  in a direction orthogonal to the radial direction so as to substantially cover the opening part of the radial direction restriction portion  85 . Therefore, the restriction portion  84  restricts the movement of the terminal line  33   a  of the terminal inner coil  83  in the circumferential direction. The insulator  32  covers the tooth  31   b  and the tooth  31   b  adjacent to the tooth  31   b  in the circumferential direction, around which the terminal inner coil  83  is wound. The restriction portion  84  is set so that the distance from the tip of the radial direction restriction portion  85  is smaller than the coil wire diameter L, and the coil  33  disposed inside the radial direction restriction portion  85  is set so as not to jump out from the radial direction restriction portion  85 . 
     The core outer extension portion  31   c  is formed such that its radially inner surface is formed in an arc shape when viewed from the axial direction. However, the radially inner surface may have a concave shape other than the arc shape. The gap between the concave shape and the first coil  79  is set larger than the coil wire diameter L. 
     Next, a method for manufacturing the stator  30  configured as mentioned above and its function will be described. 
     First, as shown in  FIG. 6 , the insulator  32  is assembled to the core constituent member  31   d  to manufacture the wound member  77 , and the coil  33 , that is specifically the terminal inner coil  83 , is wound the on the wound portion  75  including the tooth  31   b  and the tooth covering portion  32   b  by using the flyer device. 
     At this time, the winding start of the coil  33  is first inserted into the radial direction restriction portion  85 , and the coil  33  of the first layer is sequentially wound from the radially inner side toward the radially outer side. At this time, the first coil  79  and the second coil  80  are sequentially wound on the outer side in the radial direction on the wound portion  75 , and the second coil  80  is guided to the outer peripheral surface of the first coil  79  so as to be disposed on the outer side in the radial direction of the first coil  79  and in the concave portion  78 . 
     Thereafter, the coils that become the second layer and later layers are sequentially wound toward the inner side in the radial direction or the outer side in the radial direction, and the jumper wires  41   g ,  41   h ,  41   j ,  51   g ,  51   h ,  51   j  are formed along the guide portion  32   a . Thereafter, the coil  33  separated by 150 degrees is wound around the wound portion  75  connected by the guide portion  32   a.    
     Then, as shown in  FIGS. 4 and 5 , a core unit  74  is manufactured by arranging two sets of subassemblies that include coils  33  wound in the same manner side by side in the circumferential direction. At this time, the restriction portion  84  is disposed so as to substantially cover the opening part of the radial direction restriction portion  85 , so that the coil  33  disposed inside the radial direction restriction portion  85  is prevented from jumping out to the outside. Therefore, the movement of the terminal line  33   a  is prevented. 
     Three core units  74  having substantially the same configuration are assembled in the circumferential direction, and then the core outer extension portions  31   c  adjacent in the circumferential direction are welded together so as to manufacture the stator core  31 . 
     Then, as shown in  FIG. 3 , the guide body  61  of the guide member  60  is assembled to one side of the stator core  31  in the axial direction. The terminal line  33   a  of the coil  33  is led out from the notch  63  to one side in the axial direction. Further, the terminal line  33   a  is bent in the circumferential direction and led out from one part in the circumferential direction to one side in the axial direction of the pullout guide  62  through the pullout guide  62 . Then, the manufacture of the stator  30  is completed. 
     Next, the effects of the present embodiment are described below. 
     (1) On the inner side in the radial direction of the base portion of the outer extension portion  76 , the concave portion  78  that is recessed radially outward from a winding outermost diameter position A 1  is provided. The winding outermost diameter position A 1  is a virtual straight line that contacts radially inner ends at circumferential tip ends of the pair of outer extension portion  76  when viewed from the axial direction. Therefore, a space for arranging the coil  33  radially outside is ensured as compared with the case where the concave portion  78  is not provided. The first layer of the coil  33  includes a first coil  79 , a center B of which is positioned radially inward from the winding outermost diameter position A 1  and in a range between 0.5 times a coil wire diameter L and 1.5 times the coil wire diameter L with respect to the winding outermost diameter position A 1 , and a second coil  80  in which at least a part is disposed in the concave portion  78  on the radially outer side of the first coil  79 . Therefore, the coil  33  can be easily disposed in the concave portion  78 . That is, if the second coil  80  is wound along the winding outermost diameter position A 1  after the first coil  79  is wound, the second coil  80  is guided to an outer peripheral surface of the first coil  79  so that the second coil  80  can arrange radially outside the first coil  79 , and in the concave portion  78 . Therefore, the coil  33  can be easily arrange in the concave portion  78 . As a result, for example, the position of the innermost diameter of the coil  33  can be arranged on the outer side relative to the inner side in the radial direction as compared with the case where no concave portion  78  is provided, and a large space for arranging another configuration including a rotor  20  and its bearings, etc. on the inner side of the coil  33  in the radial direction can be secured. 
     (2) The insulator  32  has the first convex portion  81  that restricts the movement of the first coil  79  inward in the radial direction. Therefore, when the second coil  80  is wound after the first coil  79  is wound and the second coil  80  is guided to the outer peripheral surface of the first coil  79 , the first coil  79  is restricted from moving radially inward. Therefore, the second coil  80  can be disposed in the concave portion  78  more reliably. 
     (3) The insulator  32  has a second convex portion  82  that restricts the movement of the first coil  79  outward in the radial direction. For example, the first coil  79  is restricted from moving radially outward after the first coil  79  is wound and before the second coil  80  is wound. Therefore, the second coil  80  can be disposed in the concave portion  78  more reliably. 
     (4) The position of the top of the second convex portion  82  is arranged radially inside the winding outermost diameter position A 1  and within 0.5 times the coil wire diameter L. Therefore, if the first coil  79  is wound substantially along the winding outermost diameter position A 1 , the first coil  79  is guided to the top of the second convex portion  82 . Therefore, since the center B of the first coil  79  is larger than 0.5 times the coil wire diameter L, the first coil  79  is disposed radially inward from the winding outermost diameter position A 1 . Therefore, for example, if the first coil  79  and the second coil  80  are sequentially wound along the winding outermost diameter position A 1 , the second coil  80  can be disposed in the concave portion  78 . 
     The above described embodiments may be modified as follows. The above described embodiments and the following modifications can be implemented in combination with one another as long as there is no technical contradiction. 
     In the above embodiment, the insulator  32  has the first convex portion  81  that restricts the movement of the first coil  79  inward in the radial direction. However, if the first convex portion  81  has the same function, the shape of the first convex portion  81  may be modified. Further, the first convex portion  81  may be omitted. 
     In the above embodiment, the insulator  32  has the second convex portion  82  that restricts the movement of the first coil  79  outward in the radial direction. However, if the second convex portion  82  has the same function, the shape of the second convex portion  82  may be modified. Further, the second convex portion  82  may be omitted. 
     In the above embodiment, the center B of the first coil  79  of the present embodiment is disposed radially inward from the winding outermost diameter position A 1  by about 0.8 times the coil wire diameter L. Under the condition that the center B is disposed radially inward from the winding outermost diameter position A 1  in the range between 0.5 times a coil wire diameter L and 1.5 times the coil wire diameter L with respect to the winding outermost diameter position A 1 , the position of the center B of the first coil  79  may be changed. 
     In the above embodiment, the insulator  32  has the outer covering portion  32   c  that covers the core outer extension portion  31   c . However, the outer covering portion  32   c  may be omitted. In the above configuration, the outer extension portion  76  is constituted only by the core outer extension portion  31   c.    
     In above embodiment, although the stator  30  which has twelve teeth  31   b  is disclosed, the stators having other than the number of the teeth  31   b  may be employed. 
     In the above embodiment, the stator  30  is embodied as an armature in the inner rotor type brushless motor. However, the wound member  77  that includes the wound portion  75  extending in the radial direction and is wound with the coil  33 , and a pair of outer extension portions  76  which extend in the circumferential direction from the radially outer end portion of the wound portion  75  may be applied to armatures other than the said use. For example, the present disclosure may be embodied in a stator as an armature in an outer rotor type brushless motor or a rotor as an armature in a brushed motor. 
     Conventionally, in an assumable stator that is an armature of a motor, a core constituent member includes a tooth extending inward in a radial direction and a pair of core outer extension portions extending in a circumferential direction from an outer end in the radial direction of the teeth. A plurality of core constituent members are arranged side by side in a circumferential direction. Coils are wound around the tooth via an insulator. In such a stator, a flyer device moves in a circular motion to swivel around the tooth so as to wind the coils in a state before the core constituent members are arranged side by side in the circumferential direction. By using the flyer device, when winding the coils, the teeth of the core constituent members that are adjacent in the circumferential direction do not become an obstacle, and the coils can be easily wound. 
     By the way, in the stator as described above, it is necessary to dispose the flyer device radially inward with respect to a virtual straight line that contacts a radially inner end of the pair of core outer extension portions in the circumferential direction. Therefore, it is difficult to wind the coil radially outward with respect to the virtual straight line, and an outermost diameter of the coil becomes a position radially inward of the virtual straight line. This causes a position of an innermost diameter of the coil to move closer to the inner side in the radial direction, and it becomes impossible to secure a large space for arranging another configuration on the inner side in the radial direction of the coil. 
     The present disclosure has been made to solve the above-described problems, and an object of the present disclosure is to provide an armature in which the position of the innermost diameter of the coil can be arranged on the outer side relative to the inner side in the radial direction. 
     In order to solve the above problems, the armature includes a wound member ( 77 ) and a coil ( 33 ) wound around the wound portion. The wound member includes a wound portion ( 75 ) extending in a radial direction and a pair of outer extension portions ( 76 ) extending from an outer end in the radial direction of the wound portion to both sides in a circumferential direction. On an inner side in the radial direction of a base portion of the outer extension portions, a concave portion ( 78 ) is recessed radially outward from a winding outermost diameter position (A 1 ). The winding outermost diameter position (A 1 ) is a virtual straight line that contacts radially inner ends at circumferential tip ends of the pair of outer extension portions when viewed from the axial direction. A first layer of the coil includes a first coil ( 79 ), a center (B) of which is positioned radially inward from the winding outermost diameter position and in a range between 0.5 times a coil wire diameter (L) and 1.5 times the coil wire diameter with respect to the winding outermost diameter position, and a second coil ( 80 ) in which at least a part is disposed in the concave portion on the radially outer side of the first coil. 
     According to the above configuration, the concave portion that is recessed radially outward from the winding outermost diameter position is provided on the radially inner side of the base portion of the outer extension portion. Therefore, a space for arranging the coil on the radially outer side is ensured as compared with the case where no concave portion is provided. A first layer of the coil includes a first coil ( 79 ), a center (B) of which is positioned radially inward from the winding outermost diameter position and in a range between 0.5 times a coil wire diameter (L) and 1.5 times the coil wire diameter with respect to the winding outermost diameter position, and a second coil ( 80 ) in which at least a part is disposed in the concave portion on the radially outer side of the first coil. Therefore, the coil can be easily disposed in the concave portion. That is, if the second coil is wound along the winding outermost diameter position after the first coil is wound, the second coil is guided to an outer peripheral surface of the first coil so that the second coil can arrange radially outside the first coil, and in the concave portion. Therefore, the coil can be easily arrange in the concave portion. As a result, for example, the position of the innermost diameter of the coil can be arranged on the outer side relative to the inner side in the radial direction as compared with the case where no concave portion is provided, and a large space for arranging another configuration on the inner side of the coil in the radial direction can be secured.