Patent Publication Number: US-2022239167-A1

Title: Motor member, motor, and method for manufacturing motor member

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a U.S. national stage of application No. PCT/JP2020/027205, filed on Jul. 13, 2020, and with priority under 35 U.S.C. § 119(a) and 35 U.S.C. § 365(b) being claimed from Japanese Patent Application No. 2019-140406, filed on Jul. 31, 2019, the entire disclosures of which are hereby incorporated herein by reference. 
    
    
     1. FIELD OF THE INVENTION 
     The present disclosure relates to a motor armature, a motor, and a method for manufacturing a motor armature. 
     2. BACKGROUND 
     Conventional motors have magnetic portions that are each often formed by using a laminated body called a laminated core or the like in which magnetic steel plates or the like are laminated. Examples of the laminated core include a laminated core provided with a coil, a laminated core provided with a permanent magnet attached, and a laminated core provided with no coil and no permanent magnet, being used as a rotor as it is. As a method for fixing the laminated core to a shaft, a case, a holder, or the like at the time of manufacturing, fixing by press-fitting is common. 
     For example, a bearing holder provided with a laminated core fixed to an outer periphery of the bearing holder is conventionally known. 
     However, the magnetic steel plate or the like laminated in the laminated body is a thin and fragile member, and thus may be broken at the uppermost portion or the lowermost portion of the lamination due to press-fitting of the shaft or the like. 
     SUMMARY 
     An example embodiment of a motor armature according to the present disclosure includes a laminated body including a stack of magnetic bodies each having an annular and plate shape, an extended body that opposes an opposing peripheral surface that is at least one of an inner peripheral surface and an outer peripheral surface of the laminated body and extends along a stacking direction of the magnetic bodies, and a holder stacked on the laminated body in the stacking direction to hold the laminated body. The holder includes a plate portion that extends along the laminated body and has higher rigidity than the magnetic bodies, and a sleeve portion that extends in contact with the extended body. The extended body includes a first shoulder surface opposing an extending direction of the extended body and being in contact with the holder to position the extended body in the extending direction, and a second shoulder surface opposing a circumferential direction around the opposing peripheral surface and being in contact with the holder to position the extended body in the circumferential direction. 
     A motor according to another example embodiment of the present disclosure includes the motor armature according to the above-identified example embodiment that defines at least one of a stator and a rotor. 
     A further example embodiment of the present disclosure provides a method of manufacturing a motor armature including a laminated body including a stack of magnetic bodies each having an annular and plate shape, an extended body that opposes an opposing peripheral surface that is at least one of an inner peripheral surface and an outer peripheral surface of the laminated body and extends along a stacking direction of the magnetic bodies, and a holder stacked on the laminated body in the stacking direction to hold the laminated body. The method includes holding the holder including a plate portion that extends along the laminated body and has higher rigidity than the magnetic bodies and a sleeve portion that extends in contact with the extended body while stacking the holder on the laminated body, press-fitting the extended body into the laminated body held by the holder, the extended body including a first shoulder surface opposing an extending direction of the extended body and a second shoulder surface opposing a circumferential direction around the opposing peripheral surface, and positioning the first shoulder surface in the extending direction by bringing the first shoulder surface into contact with the holder and the second shoulder surface in the circumferential direction by bringing the second shoulder surface into contact with the holder. 
     The above and other elements, features, steps, characteristics and advantages of the present disclosure will become more apparent from the following detailed description of the example embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates structure of a motor of an example embodiment of the present disclosure. 
         FIG. 2  is an upper perspective view illustrating structure of a rotor of an example embodiment of the present disclosure. 
         FIG. 3  is a lower perspective view illustrating structure of a rotor of an example embodiment of the present disclosure. 
         FIG. 4  illustrates structure of a laminated core of an example embodiment of the present disclosure. 
         FIG. 5  is an upper perspective view illustrating detailed structure of an upper flange of an example embodiment of the present disclosure. 
         FIG. 6  is a lower perspective view illustrating detailed structure of an upper flange of an example embodiment of the present disclosure. 
         FIG. 7  is an upper perspective view illustrating detailed structure of a lower flange of an example embodiment of the present disclosure. 
         FIG. 8  is a lower perspective view illustrating detailed structure of a lower flange of an example embodiment of the present disclosure. 
         FIG. 9  illustrates detailed structure of a shaft to illustrate an assembling procedure of a rotor of an example embodiment of the present disclosure. 
         FIG. 10  is an enlarged sectional view illustrating a contact portion between an upper flange and a shaft of an example embodiment of the present disclosure. 
         FIG. 11  is an enlarged sectional view illustrating a contact portion between a lower flange and a shaft of an example embodiment of the present disclosure. 
         FIG. 12  illustrates a motor armature of a second example embodiment of the present disclosure. 
         FIG. 13  is an enlarged sectional view of a region R in  FIG. 12 . 
         FIG. 14  illustrates an upper flange, a lower flange, and a laminated core in a rotor of a modification of an example embodiment of the present disclosure. 
         FIG. 15  illustrates a shaft in a modification of an example embodiment of the present disclosure. 
         FIG. 16  illustrates a state in which a shaft of an example embodiment of the present disclosure is press-fitted. 
         FIG. 17  illustrates a modification of a flange of an example embodiment of the present disclosure. 
         FIG. 18  illustrates a state of an example embodiment of the present disclosure after an extended portion is broken. 
         FIG. 19  illustrates a motor with an outer rotor of an example embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, example embodiments of motor armatures, motors, and methods for manufacturing motor armatures of the present disclosure will be described in detail with reference to the accompanying drawings. However, to avoid unnecessarily redundant description below and facilitate understanding by those skilled in the art, unnecessarily detailed description may be eliminated. For example, detailed description of already well-known matters and duplicated description of a substantially identical configuration may be eliminated.  FIG. 1  illustrates structure of a motor  100  of the present example embodiment. 
     The motor  100  of the present example embodiment is, for example, a switched reluctance motor with an inner rotor, and is, for example, a three-phase motor. The motor  100  includes a stator  10  and a rotor  20  inserted inside the stator  10 . The stator  10  generates a rotating magnetic field, and the rotor  20  rotates around the stator  10  using the rotating magnetic field. 
     The stator  10  includes a laminated core  11  and a coil  12 . The laminated core  11  of the stator  10  includes a ring portion in an annular shape and for example, six salient poles  14  protruding from the ring portion  13  toward the rotor  20 . The coil  12  is provided by concentrated winding around a salient pole  14 , and the stator  10  includes, for example, three-phase two-pole magnetic poles. The stator  10  is inserted into and fixed to a case  15  in a cylindrical shape. 
     The rotor  20  includes a laminated core  21  and a shaft  22 . The laminated core  21  includes a cylindrical portion  23  into which the shaft  22  is inserted, and for example, four salient poles  24  protruding from the cylindrical portion  23  toward the stator  10 . 
     The rotor  20  is a motor armature of a first example embodiment of the present disclosure, and a combination of the stator  10  and the case  15  is a motor armature of a second example embodiment of the present disclosure. 
       FIGS. 2 and 3  are each a perspective view illustrating structure of the rotor  20 .  FIG. 2  illustrates an upper perspective view, and  FIG. 3  illustrates a lower perspective view. However, “up” and “down” in the present specification do not mean a gravity direction, and are “up” and “down” for convenience of description. That is, a depth direction in  FIG. 1  is referred to as a vertical direction for convenience, a side mainly illustrated in  FIG. 2  is referred to as an “upper side”, and a side mainly illustrated in  FIG. 3  is referred to as a “lower side”. 
     The shaft  22  of the rotor  20  is press-fitted into the laminated core  21  from the upper side and elongates downward. The laminated core  21  is provided with an upper flange  25  and a lower flange  26  that are stacked on the cylindrical portion  23  to hold the cylindrical portion  23  from above and below, respectively. Each of the upper flange  25  and the lower flange  26  corresponds to an example of a holder according to the present disclosure that is stacked on the laminated body in a stacking direction and holds the laminated body. 
     The upper flange  25  and the lower flange  26  stacked on the laminated core  21  protect the laminated core  21  when the rotor  20  is press-fitted. The upper flange  25  and the lower flange  26  perform positioning of the shaft  22  press-fitted. Specifically, the upper flange  25  and the lower flange  26  perform positioning of the shaft  22  in its extending direction (serve as so-called stoppers or retainers) and positioning of the shaft  22  in its circumferential direction (so-called anti-rotation). 
       FIG. 4  illustrates structure of the laminated core  21 . Description of  FIG. 4  will be with reference to  FIGS. 2 and 3  as appropriate. 
     The laminated core  21  is formed by, for example, stacking vertically a predetermined number of thin steel plates  21   a  each of which has a thickness of 0.02 to 1 mm, and has a surface with a baked insulating varnish or the like and a hole formed at the center of the surface. The steel plates  21   a  are bonded to each other, and the entire laminated core  21  is handled as one part at the time of assembling the rotor  20  or the like. The laminated core  21  corresponds to an example of a laminated body defined by stacking a plurality of magnetic bodies each having an annular and plate shape. The steel plates  21   a  stacked as the laminated core  21  are each thin, and thus are desired to be protected from being peeled or distorted when the shaft  22  is press-fitted. When the steel plate  21   a  has a thickness of 0.35 mm or less, damage is particularly likely to occur, and thus protection is required. The upper flange  25  and the lower flange  26  described above are stacked on the laminated core  21  in the stacking direction of the steel plates  21   a  and hold the laminated core  21 , thereby protecting the laminated core  21 . 
     The cylindrical portion  23  of the laminated core  21  is provided with a through-hole  23   d  into which the shaft  22  is press-fitted. The through-hole  23   d  includes inner peripheral surfaces  23   a  and  23   b , and the inner peripheral surface  23   a  close to an entrance of the through-hole  23   d  has a larger inner diameter than the inner peripheral surface  23   b  of a recessed portion of the through-hole  23   d . The inner diameter of the inner peripheral surface  23   b  of the recessed portion is substantially equal to an outer diameter of the shaft  22 . The inner peripheral surfaces  23   a  and  23   b  of the through-hole  23   d  in the laminated core  21  correspond to an example of an opposing peripheral surface according to the present disclosure. The opposing peripheral surface is at least one of an inner peripheral surface and an outer peripheral surface of the laminated body according to the present disclosure, and corresponds to the inner peripheral surface when the laminated core  21  is provided in the rotor  20 . The shaft  22  corresponds to an example of an extended body according to the present disclosure that extends along a stacking direction of the magnetic bodies in the laminated body according to the present disclosure. 
     The laminated core  21  is provided in its upper and lower surfaces with positioning holes  23   c  formed surrounding the through-hole  23   d . The positioning holes  23   c  each have a depth corresponding to a thickness of several steel plates  21   a , and are each a bottomed hole. 
       FIGS. 5 and 6  each illustrate detailed structure of the upper flange  25 .  FIG. 5  illustrates an upper perspective view, and  FIG. 6  illustrates a lower perspective view. Description of  FIGS. 5 and 6  will be with reference to  FIGS. 2, 3, and 4  as appropriate. 
     The upper flange  25  is made of a magnetic metal or a nonmagnetic metal. The upper flange  25  includes a plate portion  31  having higher rigidity than the steel plate  21   a  of the laminated core  21  and a cylindrical portion  32  extending along the inner peripheral surface  23   a  of the laminated core  21 . The plate portion  31  has a larger plate thickness than the steel plate  21   a , for example, and thus has high rigidity. The plate portion  31  is formed of, for example, a material having higher rigidity than the steel plate  21   a . The cylindrical portion  32  is formed by, for example, burring. 
     The cylindrical portion  32  has an inner diameter that is substantially equal to the outer diameter of the shaft  22  and the inner diameter of the inner peripheral surface  23   b  of the recessed portion of the laminated core  21 . The cylindrical portion  32  has an outer diameter that is substantially equal to the inner diameter of the inner peripheral surface  23   a  of an entrance portion of the laminated core  21 . The cylindrical portion  32  has a length that is substantially equal to a length of the inner peripheral surface  23   a  of the entrance portion of the laminated core  21 . Thus, when the upper flange  25  is stacked on the laminated core  21 , the cylindrical portion  32  of the upper flange  25  is fitted to the inner peripheral surfaces  23   a  and  23   b  of the laminated core  21  to form a continuous inner peripheral surface having a cylindrical shape with no step. The shaft  22  is press-fitted into the inner peripheral surface continuous as described above. 
     The plate portion  31  is connected to the cylindrical portion  32  with an edge portion  33  formed by, for example, half blanking, and the edge portion  33  is positioned below other portions of the plate portion  31  (i.e., positioned close to the laminated core  21 ). As a result, the plate portion  31  includes a shoulder surface  34  in an arc shape that is generated between the edge portion  33  and the other portions. The shoulder surface  34  faces inward. The edge portion  33  corresponds to an example of an adjacent portion of the plate portion that is adjacent to the extended body according to the present disclosure. 
     The edge portion  33  is partially provided with a key portion  35  remaining without being subjected to the half blanking. Processing the key portion  35  simultaneously with the edge portion  33  reduces man-hours. The key portion  35  has a side surface  35   a  that is a shoulder surface opposing a circumferential direction on the inner peripheral surface  23   a  of the laminated core  21 . The side surface  35   a  of the key portion  35  is also a shoulder surface opposing a circumferential direction on an outer peripheral surface of the shaft  22  inserted into the laminated core  21 . The key portion  35  corresponds to an example of a protrusion according to the present disclosure that protrudes from the adjacent portion along the extended body and comes into contact with a second shoulder surface. 
     The plate portion  31  is provided on its lower surface (i.e., a surface close to the laminated core  21 ) with dowels  36  formed by, for example, half blanking. When the upper flange  25  is stacked on the laminated core  21 , the dowels  36  enter the corresponding positioning holes  23   c  formed in the laminated core  21  to position the upper flange  25  with respect to the laminated core  21 . 
       FIGS. 7 and 8  each illustrate detailed structure of the lower flange  26 .  FIG. 7  illustrates an upper perspective view, and  FIG. 8  illustrates a lower perspective view. Description of  FIGS. 7 and 8  will be with reference to  FIGS. 2, 3, and 4  as appropriate. 
     The lower flange  26  is made of a magnetic metal or a nonmagnetic metal. The lower flange  26  includes a plate portion  41  having higher rigidity than the steel plate  21   a  of the laminated core  21  and a cylindrical portion  42  extending along the inner peripheral surface  23   a  of the laminated core  21 . The cylindrical portion  42  is formed by, for example, burring. 
     The plate portion  41  is provided on its upper surface (i.e., a surface close to the laminated core  21 ) with dowels  45  formed by, for example, half blanking. When the lower flange  26  is stacked on the laminated core  21 , the dowels  45  enters the corresponding positioning holes  23   c  formed in the laminated core  21  to position the lower flange  26  with respect to the laminated core  21 . 
     A part of the cylindrical portion  42  extending upward (i.e., toward the inside of the laminated core  21 ) in the circumferential direction is bent downward (i.e., toward a side opposite to the laminated core  21 ). In the example shown here, for example, two portions are bent to form a first protrusion  43  and a second protrusion  44 . The first protrusion  43  is formed by, for example, so-called right-angle bending, but is slightly inclined with respect to immediately below (i.e., an extending direction of the shaft  22 ). The first protrusion  43  has a leading end located closer to the center of the lower flange  26  (i.e., closer to the shaft  22 ) than its root. The second protrusion  44  is formed by, for example, so-called hemming bending. The second protrusion  44  has a root portion extending downward and is folded upward from the middle. In the following description, this folded portion (i.e., a lowermost portion of the second protrusion  44 ) is referred to as a leading end of the second protrusion  44 . 
       FIG. 9  illustrates detailed structure of the shaft  22  to illustrate an assembly procedure of the rotor  20 . 
     The shaft  22  includes a head portion  51  and a body portion  52 . The head portion  51  is thicker (larger in diameter) than the body portion  52 , and the head portion  51  protrudes toward an outer peripheral side from the body portion  52 . As a result, a shoulder surface  53  facing downward (i.e., toward a direction in which the body portion  52  extends) is formed at a boundary between the head portion  51  and the body portion  52 . 
     The head portion  51  has an outer diameter that is substantially equal to an inner diameter of the shoulder surface  34  in an arc shape of the upper flange  25 . The body portion  52  has an outer diameter that is substantially equal to an inner diameter of the cylindrical portion  32  of the upper flange  25 . 
     The head portion  51  includes a key groove  54  recessed at a portion in its circumferential direction and adjacent to the body portion  52 . The key groove  54  forms a step from an outer periphery of the head portion  51 . As a result, the key groove  54  has a shoulder surface  54   a  opposing the circumferential direction. 
     The body portion  52  includes a stop groove  55  for retaining at a portion in its extending direction. The stop groove  55  is circumferentially provided at, for example, two places. The stop groove  55  forms a step from an outer peripheral surface of the body portion  52 , and includes a shoulder surface  55   b  facing upward and a shoulder surface  55   a  facing circumferentially. The shoulder surfaces  55   a  and  55   b  of the stop groove  55  are recessed from the surface of the shaft  22 , and thus do not interfere with press-fitting of the shaft  22  to facilitate the press-fitting. 
     As the assembly procedure of the rotor  20 , first, the upper flange  25  and the lower flange  26  are stacked on upper and lower surfaces of the laminated core  21 , respectively, and the laminated core  21  is held by the upper flange  25  and the lower flange  26 . The cylindrical portions  32  and  42  provided in the upper flange  25  and the lower flange  26 , respectively, are inserted into the through-hole  23   d  (see  FIG. 4 ) of the laminated core  21 , and then the dowels  36  and  45  (see  FIGS. 6 and 7 ) provided on the upper flange  25  and the lower flange  26 , respectively, are inserted into the corresponding positioning holes  23   c  (see  FIG. 4 ) of the laminated core  21 . 
     Next, the shaft  22  is press-fitted in a direction in which the key groove  54  and the key portion  35  of the upper flange  25  are aligned with each other, and then the shaft  22  is press-fitted into the laminated core  21  held by the upper flange  25  and the lower flange  26 . When the shaft  22  is press-fitted, the key portion  35  engages with the key groove  54  to prevent rotation of the shaft  22 , the upper flange  25 , and the laminated core  21 . That is, the shaft  22  comes into contact with the shoulder surface  35   a  of the key portion  35  (i.e., a part of the upper flange  25 ) at the shoulder surface  54   a  (i.e., the shoulder surface opposing the circumferential direction around the inner peripheral surface  23   a  of the laminated core  21 , which is an example of the opposing peripheral surface) of the key groove  54 , and then the shaft  22  is positioned in the circumferential direction. The key portion  35  protrudes from the edge portion  33  along the shaft  22  and comes into contact with the shoulder surface of the key groove  54 , and thus reliably prevents rotation of the shaft  22 . 
       FIG. 10  is an enlarged sectional view illustrating a contact portion between the upper flange  25  and the shaft  22 . 
     When the dowels  36  (i.e., protrusions to be fitted into recesses) of the upper flange  25  are fitted into the corresponding positioning holes  23   c  of the laminated core  21  (i.e., recesses provided in a surface opposing the plate portion  31 ), the upper flange  25  and the laminated core  21  are positioned to each other. 
     As described above, when the key groove  54  of the head portion  51  of the shaft  22  engages with the key portion  35  of the upper flange  25 , the shaft  22  is positioned in the circumferential direction. 
     When the body portion  52  of the shaft  22  is press-fitted into the upper flange  25  and the laminated core  21 , the cylindrical portion  32  of the upper flange  25  is pushed from its inner peripheral side toward its outer peripheral side by the body portion  52 . As a result, an inner peripheral surface of the cylindrical portion  32  is in close contact with the outer peripheral surface of the shaft  22 , and an outer peripheral surface of the cylindrical portion  32  is in close contact with the inner peripheral surface  23   a  of the laminated core  21 . Beyond the cylindrical portion  32  of the upper flange  25 , the outer peripheral surface of the body portion  52  of the shaft  22  comes into close contact with the inner peripheral surface  23   b  of the laminated core  21 . The cylindrical portion  32  corresponds to an example of a sleeve portion according to the present disclosure that expands by coming into contact with the extended body according to the present disclosure. 
     The plate portion  31  of the upper flange  25  extends along the laminated core  21  and has higher rigidity than the steel plates  21   a  of the laminated core  21 . Thus, the plate portion  31  prevents the steel plates  21   a  from peeling or the like when the shaft  22  is press-fitted. The cylindrical portion  32  of the upper flange  25  expands by coming into contact with the shaft  22  and extends from the plate portion  31  toward the laminated core  21 . Thus, the cylindrical portion  32  suppresses distortion or the like of the steel plate  21   a  when the shaft  22  is press-fitted. 
     The shaft  22  is press-fitted until the shoulder surface  53  facing downward formed between the head portion  51  and the body portion  52  comes into contact with the edge portion  33  of the upper flange  25 . As a result, the shaft  22  is positioned in the extending direction by using a so-called stopper. In other words, the shaft  22  is positioned in the extending direction in contact with the upper flange  25  at the shoulder surface  53  opposing the extending direction of the shaft  22 . The shoulder surface  53  is in contact with the edge portion  33  of the plate portion  31  of the upper flange  25 , adjacent to the shaft  22 , so that the shoulder surface for positioning has a simple structure. The shaft  22  is positioned in the extending direction even when the edge portion  33  is flush with other portions of the plate portion  31  without having a step due to half-blanking or the like. 
     When the edge portion  33  has a step from the other portions of the plate portion  31  as illustrated in  FIG. 5 , i.e., when the edge portion  33  is positioned closer to the laminated core  21  than the other portions to form a step between the edge portion  33  and the other portions, an outer peripheral surface of the head portion  51  comes into contact with the shoulder surface  34  in an arc shape facing inward of the upper flange  25  by press fitting of the shaft  22 . This achieves so-called axial alignment of the shaft  22 . 
     As described above, when the shaft  22  is inserted (press-fitted) into the upper flange  25 , the shoulder surface  53  facing downward of the shaft  22  comes into contact with the upper flange  25  to be positioned in the extending direction, and the shoulder surface  54   a  opposing the circumferential direction comes into contact with the upper flange  25  to be positioned in the circumferential direction. That is, the shaft  22  is positioned in both the extending direction and the circumferential direction by press fitting of the shaft  22 . When the shaft  22  is press-fitted into the upper flange  25 , axial alignment of the shaft  22  is also achieved. That is, even a small number of members achieves the protection of the steel plates  21   a  of the laminated core  21  and the positioning of the shaft  22 . 
       FIG. 11  is an enlarged sectional view illustrating a contact portion between the lower flange  26  and the shaft  22 . 
     When the body portion  52  of the shaft  22  is press-fitted into the lower flange  26  and the laminated core  21 , the cylindrical portion  42  of the lower flange  26  is pushed from its inner peripheral side to its outer peripheral side by the body portion  52  to bring an outer peripheral surface of the cylindrical portion  42  into close contact with the inner peripheral surface  23   a  of the laminated core  21 . Then, an inner peripheral surface of the cylindrical portion  42  comes into close contact with the body portion  52  of the shaft  22 . The cylindrical portion  42  corresponds to an example of the sleeve portion according to the present disclosure that expands by coming into contact with the extended body according to the present disclosure. The laminated core  21  is protected by the plate portion  41  and the cylindrical portion  42  of the lower flange  26 , so that peeling or distortion of the steel plates  21   a  does not occur in the laminated core  21  even when the shaft  22  is press-fitted. 
     When the shaft  22  is fully press-fitted as illustrated in  FIG. 10 , each of the stop grooves  55  of the body portion  52  of the shaft  22  reaches the corresponding one of the first protrusion and the second protrusion  44  of the lower flange  26  as illustrated in  FIG. 11 . The leading end of the first protrusion  43  inclined inward is temporarily and elastically expanded by the outer peripheral surface of the body portion  52 . When the shoulder surface  55   b  facing upward of the stop groove  55  reaches the leading end of the first protrusion  43 , the first protrusion  43  is fitted into the stop groove  55  by an elastic force. 
     As a result, the leading end of the first protrusion  43  comes into contact with the shoulder surface  55   b  facing upward of the stop groove  55  to prevent the shaft  22  from coming off, and the shaft  22  is positioned in the extending direction. Then, a side surface of the first protrusion  43  comes into contact with the shoulder surface  55   a  (see  FIG. 9 ) opposing the circumferential direction of the stop groove  55  to prevent rotation of the shaft  22 , and the shaft  22  is positioned in the circumferential direction. As described above, inserting (press-fitting) the shaft  22  into the lower flange  26  facilitates positioning of the shaft  22  in both the extending direction and the circumferential direction. 
     The second protrusion  44  of the lower flange  26  is pushed into the stop groove  55  by crimping after completion of press fitting of the shaft  22 . As a result, the leading end of the second protrusion  44  comes into contact with the shoulder surface  55   b  facing upward of the stop groove  55  to prevent the shaft  22  from coming off. Then, a side surface of the second protrusion  44  comes into contact with the shoulder surface  55   a  (see  FIG. 9 ) opposing the circumferential direction of the stop groove  55  to prevent rotation of the shaft  22 . The second protrusion  44  has a structure folded back by so-called hemming bending, and thus has high strength. 
     Next, a motor armature of a second example embodiment of the present disclosure will be described. 
       FIG. 12  illustrates the motor armature of the second example embodiment of the present disclosure. 
     As described above, the combination of the stator  10  and the case  15  of the motor  100  illustrated in  FIG. 1  is the motor armature of the second example embodiment of the present disclosure. 
     The laminated core  11  of the stator  10  is press-fitted into the cylindrical case  15 , and the upper flange  16  and the lower flange  17  hold the laminated core  11  from above and below, respectively, to protect the laminated core  11 . The case  15  extends vertically along an outer peripheral surface of the laminated core  11 . The motor armature according to the second example embodiment includes the laminated core  11  that corresponds to an example of the laminated body according to the present disclosure. The outer peripheral surface of the laminated core  11  corresponds to an example of the opposing peripheral surface according to the present disclosure, and the case  15  corresponds to an example of the extended body according to the present disclosure. 
       FIG. 13  is an enlarged sectional view of a region R in  FIG. 12 . However,  FIG. 13  illustrates a schematic view, and in particular, steel plates  11   a  constituting the laminated core  11  are each drawn thicker than an actual steel plate. 
     The laminated core  11  of the stator  10  is formed by, for example, stacking vertically the steel plates  11   a  each of which is thin and has a thickness of 0.02 to 1 mm and an annular shape, and has a surface with a baked insulating varnish or the like. The steel plates  21   a  are bonded to each other, and the entire laminated core  21  is handled as one part at the time of assembling the rotor  20  or the like. The laminated core  21  corresponds to an example of the laminated body according to the present disclosure, defined by stacking a plurality of magnetic bodies each having an annular and plate shape. 
     The upper flange  16  and the lower flange  17  are stacked on the laminated core  11  in a stacking direction of the steel plates  11   a  and hold the laminated core  11 , thereby protecting the laminated core  11 . Each of the upper flange  16  and the lower flange  17  corresponds to an example of the holder according to the present disclosure that is stacked on the laminated body in the stacking direction and holds the laminated body. 
     The upper flange  16  includes a plate portion  71  having higher rigidity than the steel plate  11   a  of the laminated core  11  and a cylindrical portion  72  extending along the outer peripheral surface of the laminated core  11 . The lower flange  17  also includes a plate portion  81  having higher rigidity than the steel plate  11   a  of the laminated core  11  and a cylindrical portion  82  extending along the outer peripheral surface of the laminated core  11 . The cylindrical portions  72  and  82  of the upper flange  16  and the lower flange  17  each have an inner diameter that is substantially equal to an outer diameter of the outer peripheral surface of the laminated core  11 . 
     The laminated core  11  is provided in its upper and lower surfaces with positioning holes  62 . The positioning holes  62  are each a bottomed hole. Then, the plate portions  71  and  81  of the upper flange  16  and the lower flange  17  are respectively provided close to the laminated core  11  with dowels  73  and  83 . These dowels are inserted into the respective positioning holes  62  of the laminated core  11  to position the upper flange  16  and the lower flange  17  with respect to the laminated core  11 . 
     The case  15  includes a relatively thick upper portion  91  and a relatively thin lower portion  92 , and a shoulder surface  95  facing downward is formed between the upper portion  91  and the lower portion  92 . The lower portion  92  of the case  15  has an inner diameter that is substantially equal to an outer diameter of each of the cylindrical portions  72  and  82  of the upper flange  16  and the lower flange  17 . 
     Before the laminated core  11  is press-fitted into the case  15 , the laminated core  11  is sandwiched and held by the upper flange  16  and the lower flange  17  from above and below, respectively. 
     Then, the laminated core  11  held by the upper flange  16  and the lower flange  17  is press-fitted into the case  15 . When the laminated core  11  is press-fitted, the cylindrical portions  72  and  82  of the upper flange  16  and the lower flange  17  are pushed inward by an inner peripheral surface of the lower portion  92  of the case  15 . As a result, outer peripheral surfaces of the cylindrical portions  72  and  82  come into close contact with an inner peripheral surface of the case  15 , and inner peripheral surfaces thereof come into close contact with the outer peripheral surface of the laminated core  11 . The cylindrical portions  72  and  82  each correspond to an example of the sleeve portion according to the present disclosure that extends in contact with the extended body according to the present disclosure. 
     The laminated core  11  is sandwiched and protected by the upper flange  16  and the lower flange  17 , so that peeling or distortion of the steel plates  11   a  does not occur in the laminated core  11  even when the laminated core  11  is press-fitted into the case  15 . The laminated core  11  is press-fitted until the plate portion  71  of the upper flange  16  comes into contact with the shoulder surface  95  of the case  15 . The case  15  is positioned in the vertical direction (i.e., an extending direction of the case  15 ) by contact between the plate portion  71  of the upper flange  16  and the shoulder surface  95  of case  15 . The plate portion  71  has a portion in contact with the shoulder surface  95 , the portion corresponding to an example of the adjacent portion according to the present disclosure of the plate portion, the adjacent portion being adjacent to the extended body. 
     The plate portion  71  of the upper flange  16  is partially provided on its outer periphery with a key portion  74  protruding upward. Then, the upper portion  91  of the case  15  is provided with a key groove  93  recessed upward that is formed at a part of a boundary between the upper portion  91  and the lower portion  92 , in the circumferential direction. When the laminated core  11  is press-fitted, the key portion  74  is fitted into the key groove  93  to achieve so-called anti-rotation by contact between a side surface of the key portion  74  and an inner wall of the key groove  93 , and the case  15  is positioned in the circumferential direction. The key portion  74  corresponds to an example of the protrusion according to the present disclosure that protrudes from the adjacent portion along the extended body and comes into contact with the second shoulder surface. 
     The lower flange  17  is provided with a protrusion  84  protruding downward. Then, the lower portion  92  of the case  15  is provided with a stop groove  94  into which the protrusion  84  is fitted. After the laminated core  11  is press-fitted, the protrusion  84  is pushed into the stop groove  94  by, for example, crimping, and a leading end and a side surface of the protrusion  84  come into contact with an inner wall surface facing upward and an inner wall surface opposing a circumferential direction of the stop groove  94 , respectively. The inner wall surfaces of the stop groove  94  are each a shoulder surface with respect to the inner peripheral surface of the lower portion  92 . 
     The contact between the leading end of the protrusion  84  and the inner wall surface of the stop groove  94  achieves so-called retaining, and the case  15  is positioned in the vertical direction (i.e., the extending direction of the case  15 ). Then, the contact between the side surface of the protrusion  84  and the inner wall surface of the stop groove  94  achieves so-called anti-rotation, and the case  15  is positioned in the circumferential direction. 
     As described above, inserting (press-fitting) the laminated core  11  into the case  15  easily achieves positioning in both the extending direction and the circumferential direction of the case  15 . 
     Next, a modification of the rotor  20  described above will be described. 
       FIG. 14  illustrates an upper flange, a lower flange, and a laminated core in a rotor of the modification. 
     Even in the modification, a laminated core  121  defined by stacking steel plates  121   a  is used, and the laminated core  121  is provided in its upper and lower surfaces with positioning holes  121   c . Even in the modification, an upper flange  125  and a lower flange  126  include plate portions  131  and  141 , and cylindrical portions  132  and  142 , respectively. The plate portions  131  and  141  are each provided on its surface close the laminated core  121  with dowels  136  and  145 , respectively, which are formed by half-blanking, for example. 
     The cylindrical portions  132  and  142  of the upper flange  125  and the lower flange  126  of the modification extend toward a side opposite to the laminated core  121 . The laminated core  121  is provided with a through-hole  121   d  that has a constant inner diameter over the entire length. The through-hole  121   d  has an inner diameter that is substantially equal to an inner diameter of each of the cylindrical portions  132  and  142 . 
     Prior to press-fitting of a shaft to be described later, the laminated core  121  is sandwiched and held by the upper flange  125  and the lower flange  126  from above and below, respectively. At this time, the dowels  136  and  145  of the upper flange  125  and the lower flange  126  enter the corresponding positioning holes  121   c  of the laminated core  121  to position the upper flange  125  and the lower flange  126  with respect to the laminated core  121 . 
       FIG. 15  illustrates a shaft in the modification. 
     The shaft  122  in the modification is provided in its outer peripheral surface with a crimping groove  123  extending in a circumferential direction. The crimping groove  123  forms a step with respect to the outer peripheral surface of the shaft  122 , and includes a shoulder surface  125  facing downward and a shoulder surface  126  facing upward as shoulder surfaces opposing an extending direction of the shaft  122 . The crimping groove  123  is partially disconnected to form a shoulder surface  124  opposing the circumferential direction of the shaft  122 . 
       FIG. 16  illustrates a state in which the shaft  122  is press-fitted. However,  FIG. 16  does not illustrate the laminated core  121 , and thus description of  FIG. 16  is also with reference to  FIG. 14 . The description of  FIG. 16  is also with reference to  FIG. 15  without particularly denoting the figure number. 
     When the laminated core  121  is sandwiched between the upper flange  125  and the lower flange  126  as described above, the shaft  122  is then press-fitted into the laminated core  12  held by the upper flange  125  and the lower flange  126 . The laminated core  121  is protected by the plate portions  131  and  141  of the upper flange  125  and the lower flange  126 , so that peeling or distortion of the steel plates  121   a  does not occur even when the shaft  122  is press-fitted. 
     The shaft  122  is press-fitted to a position where crimping grooves  123  overlaps the corresponding cylindrical portions  132  and  142  of the upper flange  125  and the lower flange  126 , and then the cylindrical portions  132  and  142  are crimped and pushed into the corresponding crimping grooves  123 . Then, both the shoulder surface  124  facing circumferentially and the shoulder surfaces  125  and  126  facing vertically of each of the crimping grooves  123  come into close contact with the corresponding one of the cylindrical portions  132  and  142 . As a result, the shaft  122  is positioned in both the extending direction and the circumferential direction. 
     As described above, a rotor is assembled by press-fitting the shaft  122  and crimping the cylindrical portions  132  and  142  in the modification. 
     Next, modifications of the upper flange  25  and the lower flange  26  will be described. 
       FIG. 17  illustrates a modification of a flange. 
     Although  FIG. 17  illustrates application of the modification to the lower flange  26  as an example, this modification is similarly applicable to the upper flange  25 . That is, the lower flange  26  in the modification includes a plate portion  41  that is partially provided with an extended portion  45  extending in a direction away from the shaft  22 . For example, extended portions  45  here extend in four directions. When the lower flange  26  is stacked on the laminated core  21 , the extended portions  45  overlies respective four salient poles  24  provided in the laminated core  21  to protect the salient poles  24 . This protects the salient poles  24  at the time of press-fitting work or the like, and prevents peeling or distortion of the steel plates  21   a.    
     The extended portions  45  are each provided with a breaking groove  45   a  having a V-shape in section, and a leading end portion beyond the breaking groove  45   a  of each of the extended portions  45  is removed after the shaft  22  is press-fitted. 
       FIG. 18  illustrates a state after the extended portions  45  are broken. 
     The presence of the extended portions  45  facilitates handling of the laminated core  21  and the like at the time of press-fitting work and the like, and the extended portions  45  contribute to protection of the laminated core  21 . In contrast, a structure with the laminated core  21  covered with a resin insulator does not need the extended portions  45 . The extended portions  45  may cause an eddy current to deteriorate motor efficiency. 
     Thus, the extended portions  45  are each bent and broken at a location of the breaking groove  45   a  (see  FIG. 17 ), and the leading end portion beyond the breaking groove  45   a  is removed. 
     The plate portion  41  of the lower flange  26  after the removal has a fracture surface  45   b  at a portion of an edge away from the shaft (i.e., a portion at which the leading end portion of each of the extended portions  45  is removed). Each of the extended portions  45  may be broken at its root to remove the entire extended portion  45 . 
     Next, a motor with an outer rotor will be described as an example of a motor to which the structure of motor components according to the first example embodiment or the second example embodiment of the present disclosure is applicable. 
       FIG. 19  illustrates a motor with an outer rotor. 
     A motor  200  with an outer rotor includes a rotor  210  and a stator  220 . The rotor  210  surrounds the stator  220  and rotates around the stator  220 . The rotor  210  includes a laminated core  211  and a case  212 , and the laminated core  211  is press-fitted into the case  212  to integrate the laminated core  211  and the case  212 . 
     The stator  220  includes a laminated core  221 , a coil  222 , and a stator holder  223 , and the stator holder  223  is press-fitted into the laminated core  221  to be integrated with the laminated core  221 . The laminated core  221  includes a plurality of (e.g., here twelve) salient poles  224 , and the coil  222  is wound around each of the salient poles  224  by, for example, concentrated winding. 
     For example, the structure of the second example embodiment illustrated in  FIGS. 12 and 13  is applied to the rotor  210  of the motor  200  illustrated in  FIG. 19 . The structure of the second example embodiment protects the laminated core  211  when the laminated core  211  is press-fitted into the case  212 , and positions the laminated core  211  with respect to the case  212  as the laminated core  211  is press-fitted. 
     For example, the structures of the first example embodiment illustrated in  FIGS. 2 to 11  and the modification illustrated in  FIGS. 14 to 16  are applied to the stator  220  illustrated in  FIG. 19 . The structure of the first example embodiment or the modification protects the laminated core  221  when the stator holder  223  is press-fitted into the laminated core  221 , and positions the stator holder  223  with respect to the laminated core  221  as the stator holder  223  is press-fitted, or press-fitted and crimped. 
     Although in the above description, examples of the application target in the motor armature, the motor, and the method for manufacturing a motor armature of the present disclosure include a reluctance motor, the application target of the motor armature, the motor, and the method for manufacturing a motor armature of the present disclosure is not limited to the above, and those of the present disclosure are applicable to various motors using a laminated core, such as a DC motor, an AC motor, and a stepping motor. 
     Although in the above description, examples of the application target in the motor armature, the motor, and the method for manufacturing a motor armature of the present disclosure include a three-phase motor, the motor armature, the motor, and the method for manufacturing a motor armature of the present disclosure may be applied to a single-phase motor or an n-phase motor other than the three-phase motor. 
     It is to be considered that the example embodiments described above are illustrative in all aspects, and are not restrictive. The scope of the present disclosure is indicated by the scope of claims rather than the example embodiments described above, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims. 
     Features of the above-described example embodiments and the modifications thereof may be combined appropriately as long as no conflict arises. 
     While example embodiments of the present disclosure have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present disclosure. The scope of the present disclosure, therefore, is to be determined solely by the following claims.