Abstract:
To provide a stator of a motor having an insulating structure achieving insulation easily and reliably. A stator ( 1 ) of a motor comprises: a teeth unit ( 11 ) with a circular cylindrical part ( 111 ) having a circular cylindrical shape and multiple projection parts ( 112 ) spaced uniformly along an outer circumference of the circular cylindrical part ( 111 ) in a circumferential direction of the circular cylindrical part ( 111 ), the projection parts ( 112 ) projecting radially outwardly from the circular cylindrical part ( 111 ); multiple bobbins ( 13 ) having cylindrical shapes with hollow sections ( 133 ) through which the projection parts ( 112 ) of the teeth unit ( 11 ) are passed to be fitted in the hollow sections ( 133 ), the bobbins ( 13 ) having outer peripheries around which windings ( 14 ) are wound; a cylindrical external unit ( 12 ) arranged radially outside the teeth unit ( 11 ) and fitted to an outer circumference of the teeth unit ( 11 ) and the outer peripheries of the bobbins ( 13 ); and multiple first insulating parts ( 15 ) arranged to fill gaps between the circular cylindrical part ( 111 ) of the teeth unit ( 11 ) and the bobbins ( 13 ) and electrically insulating the teeth unit ( 11 ) and the windings ( 14 ).

Description:
[0001]    This application is based on and claims the benefit of priority from Japanese Patent Application No. 2016-080873, filed on 14 Apr. 2016, the content of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
     Field of the Invention 
       [0002]    The present invention relates to a stator of a motor having an insulating structure. 
       Related Art 
       [0003]    In motors used in various industrial devices in recent years, windings attached to stators have been arranged more densely for purposes of further size reduction and higher performance. However, densely arranging the windings causes the risk of contact of a winding with a teeth unit, or contact between adjacent windings of different phases. 
         [0004]    Hence, a stator has been required to have improved insulating properties in terms of safety. In this regard, various stators having insulating structures have been suggested (see patent document 1 and patent document 2, for example). Patent documents 1 and 2 recite that the insulating properties of a stator can be improved by inserting insulating paper or an insulating plate between a winding and a teeth unit, or between the phases of windings. 
         [0005]    Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2000-333399 
         [0006]    Patent Document 2: Japanese Patent No. 5297364 
       SUMMARY OF THE INVENTION 
       [0007]    However, a conventional stator has a required troublesome process of inserting insulating paper or an insulating plate between a winding and a teeth unit or between the phases of windings requires a large amount man-hours. 
         [0008]    A molded stator split into a teeth unit and an external unit covering the outer periphery of the teeth unit is manufactured by injection molding. This has caused a problem in the conventional stator in that application of injection pressure during injection molding moves a winding to deviate the winding from its position, or deforms insulating paper, for example. This causes the risk of insulation failure due to contact between a winding and the teeth unit, or contact between windings of different phases. 
         [0009]    The present invention has been made in view of the above-described circumstances. The present invention is intended to provide a stator of a motor having an insulating structure, achieving insulation easily and reliably. 
         [0010]    (1) A stator (a stator  1  described later, for example) of a motor according to the present invention comprises: a teeth unit (a teeth unit  11  described later, for example) with a circular cylindrical part (a circular cylindrical part  111  described later, for example) having a circular cylindrical shape and multiple projection parts (projection parts  112  described later, for example) spaced uniformly along an outer circumference of the circular cylindrical part in a circumferential direction of the circular cylindrical part, the projection parts projecting radially outwardly from the circular cylindrical part; multiple bobbins (bobbins  13  described later, for example) having cylindrical shapes with hollow sections (hollow sections  133  described later, for example) through which the projection parts of the teeth unit are passed to be fitted in the hollow sections, the bobbins having outer peripheries around which windings (windings  14  described later, for example) are wound; a cylindrical external unit (an external unit  12  described later, for example) arranged radially outside the teeth unit, and fitted to an outer circumference of the teeth unit and the outer peripheries of the bobbins; and multiple first insulating parts (first insulating parts  15  described later, for example) arranged to fill gaps between the circular cylindrical part of the teeth unit and the bobbins, and electrically insulating the teeth unit and the windings. 
         [0011]    (2) In the stator of a motor described in (1), the multiple first insulating parts may be integrated with the teeth unit. 
         [0012]    (3) In the stator of a motor described in (1) or (2), the stator may further comprise multiple second insulating parts (interphase insulating parts  161  described later, for example) each arranged to be fitted in a gap (a gap C, Ca, or Cb described later, for example) formed between adjacent ones of the bobbins, and electrically insulating windings of different phases wound around the adjacent bobbins. 
         [0013]    (4) In the stator of a motor described in (3), the multiple second insulating parts may be integrated. 
         [0014]    The present invention is capable of providing a stator of a motor having an insulating structure achieving insulation easily and reliably. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a radially-taken sectional view of a stator according to a first embodiment; 
           [0016]      FIG. 2  is a perspective view of a teeth unit of the stator according to the first embodiment; 
           [0017]      FIG. 3  is an exploded perspective view of the stator according to the first embodiment; 
           [0018]      FIG. 4  explains the working effect achieved by the stator according to the first embodiment; 
           [0019]      FIG. 5  is a radially-taken sectional view of a stator according to a second embodiment; 
           [0020]      FIG. 6  is a perspective view of a second insulating part of the stator according to the second embodiment; 
           [0021]      FIG. 7  explains the working effect achieved by the stator according to the second embodiment; 
           [0022]      FIG. 8  explains a stator according to a first conventional example; 
           [0023]      FIG. 9  explains a stator according to a second conventional example; 
           [0024]      FIG. 10  explains a stator according to a third conventional example; and 
           [0025]      FIG. 11  explains the stator according to the third conventional example. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    Embodiments of the present invention will be described below in detail by referring to the drawings. In the description of a second embodiment, configurations common to those of a first embodiment will be given the same signs and explanations of such configurations will be omitted. 
       First Embodiment 
       [0027]      FIG. 1  is a radially-taken sectional view of a stator  1  according to the first embodiment of the present invention.  FIG. 2  is a perspective view of a teeth unit  11  of the stator  1  according to the first embodiment.  FIG. 3  is an exploded perspective view of the stator  1  according to the first embodiment. Illustration of an external unit  12  is omitted from  FIG. 3 . 
         [0028]    Both the stator  1  according to this embodiment and a rotor not shown in the drawings are components of a motor. As shown in  FIGS. 1 to 3 , the stator  1  of the motor according to this embodiment is a molded stator split into the teeth unit  11  and the external unit  12 . 
         [0029]    The teeth unit  11  is formed by laminating multiple magnetic steel plates in the axis direction of the stator  1 . The teeth unit  11  includes a circular cylindrical part  111  and multiple projection parts  112 . By the presence of the circular cylindrical part  111  and the projection parts  112 , multiple slots  113  are formed in a circumferential direction. 
         [0030]    The circular cylindrical part  111  has a circular cylindrical shape and is arranged at a radially inside position of the stator  1 . The rotor not shown in the drawings is rotatably arranged in a hollow section of the circular cylindrical part  111 . The projection part  112  is formed to project radially outwardly from the circular cylindrical part  111 . The projection part  112  includes multiple projection parts  112  spaced uniformly in the circumferential direction of the circular cylindrical part  111 . All the projection parts  112  extend from one end toward an opposite end of the stator  1  in the axis direction of the stator  1 . The projection part  112  has a shape to be fitted in a hollow section of a bobbin  13  described later. 
         [0031]    The external unit  12  is provided to cover the outer circumference of the teeth unit  11 . The external unit  12  forms an external section of the stator  1 . Like the teeth unit  11 , the external unit  12  is formed by laminating multiple magnetic steel plates in the axis direction of the stator  1 . As described above, the stator  1  according to this embodiment is a molded stator. Resin is poured into the slot  113  surrounded by the external unit  12  and the teeth unit  11  from the axis direction of the stator  1 . As shown in  FIG. 1 , the external unit  12  according to this embodiment has a substantially square shape in a radially-taken sectional view, with all the corners cut out into semi-circular shapes. However, this is not the only shape of the external unit  12 . 
         [0032]    The stator  1  includes the bobbin  13 , a winding  14 , and a first insulating part  15 . 
         [0033]    The bobbin  13  includes a rectangular cylindrical part  131  of a substantially rectangular cylindrical shape, and a pair of rectangular plate parts  132  like flanges provided at opposite ends of the rectangular cylindrical part  131 , and extending in the axis direction of the rectangular cylindrical part  131 . The projection part  112  of the teeth unit  11  is passed through the hollow section  133  of the rectangular cylindrical part  131  to be fitted in the hollow section  133 . In this way, multiple bobbins  13  are arranged on the outer circumference of the teeth unit  11 . A radially-extending gap C is formed between bobbins  13  adjacent to each other in the circumferential direction. 
         [0034]    The pair of rectangular plate parts  132  includes an inner rectangular plate part  132   a  arranged at a radially inside position, and an outer rectangular plate part  132   b  arranged at a radially outside position. Each of the inner rectangular plate part  132   a  and the outer rectangular plate part  132   b  has a substantially rectangular annular shape. The outer rectangular plate part  132   b  is formed into a width dimension larger than that of the inner rectangular plate part  132   a . In this way, the bobbins  13  are allowed to be arranged densely in the circumferential direction along the outer circumference of the teeth unit  11 . The gap C between adjacent bobbins  13  is defined by a gap Ca formed between adjacent inner rectangular plate parts  132   a , and a gap Cb formed between adjacent outer rectangular plate parts  132   b.    
         [0035]    As described above, the projection part  112  of the teeth unit  11  is passed through the hollow section  133  of the rectangular cylindrical part  131  to be fitted in the hollow section  133 . The winding  14  is wound a given number of turns along the outer periphery of the rectangular cylindrical part  131 . In this way, the winding  14  is arranged in the slot  113 . 
         [0036]    The winding  14  wound along the outer periphery of the rectangular cylindrical part  131  of the bobbin  13  is arranged to extend in the axis direction of the stator  1 . Windings  14  adjacent to each other in the circumferential direction have different phases. The winding  14  has one end connected to one end of a different winding  14 , and an opposite end routed to a wiring board connected to a power connector not shown in the drawings, thereby forming a three-phase connection. 
         [0037]    The first insulating part  15  is arranged to fill a gap between the circular cylindrical part  111  of the teeth unit  11  and the bobbin  13 . In a conventional stator, a gap is formed between a circular cylindrical part of a teeth unit and a bobbin. By contrast, according to this embodiment, the first insulating part  15  is arranged to fill this gap. In this way, the first insulating part  15  is fitted between the circular cylindrical part  111  of the teeth unit  11  and the bobbin  13 . 
         [0038]    The first insulating part  15  is formed of an electrically-insulating member. This forms electrical insulation between the teeth unit  11  and the winding  14 . According to this embodiment, the first insulating part  15  has a substantially rhombic shape in a radially-taken section view, and extends in the axis direction of the stator  1 . 
         [0039]    The first insulating part  15  according to this embodiment is formed integrally with the teeth unit  11  by insert molding of the teeth unit  11  during injection molding. Specifically, the first insulating part  15  is formed by injection molding. 
         [0040]    The following describes the working effect achieved by the stator  1  according to this embodiment in detail by making comparison to conventional stators. 
         [0041]      FIG. 8  explains a stator  7  according to a first conventional example. More specifically,  FIG. 8  shows the winding  14  and its surrounding in a radially-taken sectional view of the stator  7 . As shown in  FIG. 8 , in the stator  7  according to the first conventional example, the gap C formed between bobbins  73 ,  73  adjacent to each other in the circumferential direction extends to the circular cylindrical part  111  of the teeth unit  11 . Specifically, a radially inside surface of the bobbin  73  abuts on the outer circumferential surface of the circular cylindrical part  111 . An insulating member such as insulating paper is not arranged between the radially inside surface of the bobbin  73  and the outer circumferential surface of the circular cylindrical part  111 . In the stator  7 , resin is poured in under high injection pressure during injection molding from a wide gap (gap Cb) at a radially outside position toward a narrow gap (gap Ca) at a radially inside position, as shown by arrows in  FIG. 8 . Then, the winding  14  is moved toward the gap Ca at the radially inside position by the resin poured in to pass through the gap Ca, thereby causing the risk of contact of the resin with the circular cylindrical part  111  of the teeth unit  11 . 
         [0042]      FIG. 9  explains a stator  8  according to a second conventional example. More specifically,  FIG. 9  shows the winding  14  and its surrounding in a radially-taken sectional view of the stator  8 . As shown in  FIG. 9 , in the stator  8  according to the second conventional example, a gap is formed between a radially inside surface of a bobbin  83  and the outer circumferential surface of the circular cylindrical part  111  of the teeth unit  11 . Insulating paper  17  is arranged in the gap to extend along the outer circumferential surface of the circular cylindrical part  111 . Thus, even if the winding  14  is moved to the gap Ca by application of injection pressure, the presence of the insulating paper  17  prevents the winding  14  from reaching the circular cylindrical part  111  of the teeth unit  11 , thereby ensuring insulating properties. 
         [0043]    However, when using the stator  8  according to the second conventional example, the low rigidity of the insulating paper  17  causes the insertion of the insulating paper  17  into the gap to become a difficult and complicated process. This creates a problem in that a large amount of man-hours are required. Additionally, difficulty in inserting the insulating paper  17  causes the risk of failing to arrange the insulating paper  17  at a proper position. In this case, insulation failure might occur. 
         [0044]      FIGS. 10 and 11  explain a stator  9  according to a third conventional example. More specifically,  FIGS. 10 and 11  show the winding  14  and its surrounding in a radially-taken sectional view of the stator  9 .  FIG. 10  shows a state before injection molding.  FIG. 11  shows a state during injection molding. As shown in  FIG. 10 , in the stator  9  according to the third conventional example, the gap C is formed between the bobbins  73 ,  73  to extend to the circular cylindrical part  111  of the teeth unit  11 , like in the above-described first conventional example. Radially-extending insulating paper  18  is arranged in the gap C. The insulating paper  18  extends from the outer circumferential surface of the circular cylindrical part  111  to an outer rectangular plate part  732   b  of the bobbin  73 . 
         [0045]    Like in the above-described second conventional example, the stator  9  according to the third conventional example encounters a problem in that large man-hours are required for manufacture. As shown by arrows in  FIG. 11 , if resin is poured in radially inwardly from the gap Cb at a radially outside position under high injection pressure during injection molding, the insulating paper  18  and the winding  14  are together moved radially inwardly. This causes deformation such as folding of the insulating paper  18 , and the deformed insulating paper  18  is shifted toward the circular cylindrical part  111 . This causes the risk of insulation failure. 
         [0046]    As described above, sufficient insulating properties cannot actually be ensured by any of the conventional examples 1, 2, and 3. By contrast, sufficient insulating properties are ensured in the stator  1  according to this embodiment.  FIG. 4  explains the working effect achieved by the stator  1  according to this embodiment. More specifically,  FIG. 4  shows the winding  14  and its surrounding in the radially-taken sectional view of the stator  1  shown in  FIG. 1 . 
         [0047]    As shown by arrows in  FIG. 4 , resin is also poured in radially inwardly from the gap Cb at the radially outside position under high injection pressure during injection molding. Meanwhile, the first insulating part  15  is arranged to be fitted in the gap between a radially inside surface of the bobbin  13  and the outer circumferential surface of the circular cylindrical part  111  of the teeth unit  11  so as to fill this gap. Thus, even if the winding  14  is moved toward the circular cylindrical part  111  by application of the injection pressure, the winding  14  is blocked by the first insulating part  15  and does not reach the teeth unit  11  accordingly. A gap is not formed between the radially inside surface of the bobbin  13  and the outer circumferential surface of the circular cylindrical part  111  of the teeth unit  11 . This naturally reduces the amount of resin to be poured into the gap C between the bobbins  13 . This also restricts move of the winding  14  to reduce the probability of contact between the windings  14 . As a result, high insulating properties are achieved in the stator  1  according to this embodiment. 
         [0048]    This embodiment achieves the following effects. According to this embodiment, in the stator  1  including the teeth unit  11  and the external unit  12  as split units, the first insulating part  15  for electrically insulating the teeth unit  11  and the winding  14  is arranged so as to fill the gap between the circular cylindrical part  111  of the teeth unit  11  and the bobbin  13 . Thus, as described above, the presence of the first insulating part  15  prevents the winding  14  from contacting the outer circumferential surface of the circular cylindrical part  111  of the teeth unit  11 . At the same time, the probability of contact between adjacent windings  14  of different phases is reduced. Thus, the stator  1  according to this embodiment achieves an insulating structure with rigidity having resistance to injection pressure, thereby preventing insulation failure. 
         [0049]    According to this embodiment, the multiple first insulating parts  15  are formed integrally with the teeth unit  11 . This eliminates the need for insertion of the first insulating parts  15  to achieve significant reduction in man-hours. In particular, the first insulating parts  15  and the teeth unit  11  are integrally formed by insert molding of the teeth unit  11  using injection molding. This achieves the above-described effect more reliably. 
       Second Embodiment 
       [0050]      FIG. 5  is a radially-taken sectional view of a stator  2  according to the second embodiment. As shown in  FIG. 5 , the stator  2  according to this embodiment has the same configuration as the stator  1  according to the first embodiment, except that the stator  2  further includes a second insulating member  16 . 
         [0051]      FIG. 6  is a perspective view of the second insulating member of the stator  2  according to this embodiment. As shown in  FIG. 6 , the second insulating member  16  includes multiple interphase insulating parts  161  and a coupling part  162 . The multiple interphase insulating parts  161  are each fitted in the gap C between adjacent windings  14  of different phases. The interphase insulating part  161  has an elongated rectangular shape in a radially-taken sectional view and extends in the radial direction of the stator  2 . The interphase insulating part  161  extends from one end toward an opposite end of the stator  2  in the axis direction of the stator  2 . The second insulating member  16  is formed of an electrically-insulating member and forms electrical insulation between windings  14  of different phases. 
         [0052]    The coupling part  162  is arranged at one end of the interphase insulating part  161 . The coupling part  162  has an annular shape. The multiple interphase insulating parts  161  are coupled to be integrated by the coupling part  162 . 
         [0053]      FIG. 7  explains the working effect achieved by the stator  2  according to the second embodiment. As shown in  FIG. 7 , the presence of the second insulating member  16  (interphase insulating part  161 ) restricts move of the winding  14  to reduce the probability of contact between windings  14  of different phases during injection molding of the stator  2 . 
         [0054]    This embodiment achieves the following effect in addition to the above-described effects achieved by the first embodiment. According to this embodiment, the multiple interphase insulating parts  161  are further provided. Each of the interphase insulating parts  161  is fitted in a gap formed between adjacent bobbins  13  and electrically insulates windings  14  of different phases wound around the adjacent bobbins  13 . Thus, as described above, move of the winding  14  to be caused by application of injection pressure is restricted to further reduce the probability of contact between the windings  14  of different phases. 
         [0055]    According to this embodiment, the multiple interphase insulating parts  161  are formed as an integrated part. Thus, the interphase insulating parts  161  can be inserted in a single process, thereby achieving reduction in man-hours. 
         [0056]    The present invention is not limited to the above-described embodiments, and modifications, improvements, etc. can be covered by the present invention as long as such modifications, improvements, etc. are in a range that achieves the purpose of the present invention. 
       EXPLANATION OF REFERENCE NUMERALS 
       [0000]    
       
         
           
               1 ,  2  Stator 
               11  Teeth unit 
               12  External unit 
               13  Bobbin 
               14  Winding 
               15  First insulating part 
               16  Second insulating member 
               111  Circular cylindrical part 
               112  Projection part 
               133  Hollow section 
               161  Interphase insulating part (second insulating part) 
             C, Ca, Cb Gap