Abstract:
Conductors comprising a U-phase coil, a V-phase coil and a W-phase coil are arranged in multiple slots in a stator forming a rotating electric machine. These U-phase coils, V-phase coils and W-phase coils are equipped with wave-wound parts, which have bridging parts on one end-face side of the stator core, and lap-wound parts, which are adjacent to the wave-wound parts and are formed so as to encircle the one end face and the other end face of the stator core. The wave-wound parts and the lap-wound parts are arranged so as to alternate in the winding direction of the conductors.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a rotary electric machine, which is operated as an electric motor or an electricity generator, having coils accommodated in slots of a stator for generating a rotating magnetic field. 
       BACKGROUND ART 
       [0002]    Heretofore, a rotary electric machine has been known having a stator formed in an annular shape, and a rotor that is inserted rotatably in a center portion of the stator, and in which a rotating magnetic field is generated by plural coils that are wound in slots of the stator for causing the rotor to rotate. 
         [0003]    As a method for winding such coils in plural slots, a general wave winding method is known. The wave winding method involves winding the coils alternately to crossover one end and another end of the stator. Further, in the aforementioned wave winding, a two-layer type of winding is known by which coils of different phases are arranged with respect to the same slots. With such two-layer windings, for example, as disclosed in Japanese Laid-Open Patent Publication No. 2005-110431, when plural coils are arranged in the same slots, since coils of different phases are arranged in the slots, it is possible to generate magnetic fields smoothly and stably. 
       SUMMARY OF INVENTION 
       [0004]    Recently, there has been a demand for a rotary electric machine that is smaller in size. For example, as one countermeasure for reducing the size in the axial direction, it has been considered to shorten the crossover regions at which coils cross from certain ones of the slots to other ones of the slots, whereby the crossover heights of the coils with respect to the stator can be reduced. 
         [0005]    However, in a rotary electric machine in which a two-layer winding structure is adopted as described above, in the event that a measure is taken to shorten the lengths of the crossover regions, although it is required to shorten the pitch at which the coils are arranged in two of the slots, upon shortening the aforementioned pitch, the coil pitch becomes shifted or offset with respect to the pitch of the magnetic poles of the rotor disposed in the interior of the stator, so that it becomes difficult to drive the rotary electric machine smoothly. 
         [0006]    A general object of the present invention is to provide a rotary electric machine in which, by suppressing a crossover height at which the coils crossover the stator core, the rotary electric machine can be made smaller in size in the axial direction, and the rotary electric machine can be driven smoothly and stably. 
         [0007]    The present invention is characterized by a rotary electric machine equipped with coils disposed in slots of a core, wherein the coils comprise: 
         [0008]    wave windings, which are wound with respect to the slots at a first slot pitch; and 
         [0009]    lap windings, which are wound adjacent to the wave windings at a second slot pitch, 
         [0010]    wherein the wave windings and the lap windings are arranged alternately in a direction of the first and second slot pitches, and in at least a portion of the slots among the slots, respective windings of different phases are arranged together. 
         [0011]    According to the present invention, a two-layer winding configuration is adopted, in which, in the coils, wave windings, which are wound with respect to the slots at a first slot pitch, are provided, and lap windings, which are wound adjacent to the wave windings at a second slot pitch, are provided. The wave windings and the lap windings are arranged alternately in a direction of the first and second slot pitches, and in at least a portion of the slots, respective windings of different phases are arranged together. Accordingly, compared to the two-layer configuration of the conventional technique, the distance in the pitch direction (winding direction) of the coils can be shortened, while additionally, a shift or offset between the pitch of the coils and the pitch of the magnetic poles of the rotating body that rotates with respect to the core can be prevented. As a result, the crossover height at which the coils crossover the ends of the core can be suppressed, along with enabling the rotary electric machine to be made smaller in size in the axial direction, and to be driven smoothly and stably. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0012]      FIG. 1  is an exterior perspective view showing a condition, in a rotary electric machine according to an embodiment of the present invention, in which conductors thereof are taken out; 
           [0013]      FIG. 2  is a circuit diagram of conductors that constitute the rotary electric machine of  FIG. 1 ; 
           [0014]      FIG. 3  is a schematic cross sectional view showing an arrangement of U-phase coils and V-phase coils of conductors, which are arranged in slots of a stator of  FIG. 2 ; 
           [0015]      FIG. 4  is a plan view, with partial omission of the stator, showing a condition in which the conductors of  FIG. 3  are arranged in respective slots; and 
           [0016]      FIG. 5  is a schematic cross sectional view showing an arrangement of first and second coils of the U-phase coils of the conductors, according to a modification. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0017]    As shown in  FIG. 1 , a rotary electric machine  10 , for example, is a 3-phase AC brushless motor, which includes an annular stator  12 . A non-illustrated rotor is inserted rotatably in the interior of the stator  12 . In the rotary electric machine  10 , the rotor is driven rotatably based on electric power, which is supplied from a non-illustrated power source through terminals including a U-phase terminal  14 , a V-phase terminal  16 , and a W-phase terminal  18 , respectively, as shown in  FIG. 2 . 
         [0018]    The stator  12  is constituted from an annular stator core (core)  20 , teeth  22 , which are formed to project radially inward from the stator core  20 , and plural conductors (coils)  26 , which are installed in slots  24  that are disposed on outer circumferential sides with respect to the teeth  22 . 
         [0019]    The slots  24  are formed in plurality in the stator core  20  and are separated mutually by equal distances. The stator core  20  is formed with the slots  24  extending from one end surface  20   a  to another end surface  20   b  in the axial direction (the directions of the arrow A) of the stator core  20 . The one end surface  20   a  and the other end surface  20   b  of the stator core  20  are formed substantially parallel to one another. 
         [0020]    The conductors  26 , for example, are made up from divided conductors  28 , which are substantially U-shaped, for example, by bending rectangular conductive plates, which are rectangularly shaped in cross section, including respective pairs of straight line portions  30   a ,  30   b , and respective top portions  32  where the ends of the straight line portions  30   a ,  30   b  are connected to each other. In addition, the divided conductors  28  are connected to any one of a U-phase terminal  14 , a V-phase terminal  16 , and a W-phase terminal  18 , respectively, to thereby form the same phases (e.g., a U-phase, a V-phase, or a W-phase). More specifically, the distal ends of the straight line portions  30   a ,  30   b  of the divided conductors  28  are of an open shape, whereas the proximal ends thereof are connected together in a closed shape to thereby form the top portions  32 . 
         [0021]    Further, as shown in  FIG. 2 , the conductors  26  are composed of a U-phase coil  34 , a V-phase coil  36 , and a W-phase coil  38  in three phases. The U-phase coil  34 , to which the U-phase terminal  14  is connected, is composed of first and second coils U 1 , U 2 , which are connected in series from one end portion connected to the U-phase terminal  14  to another end portion. The V-phase coil  36 , to which the V-phase terminal  16  is connected, is composed of first and second coils V 1 , V 2 , which are connected in series from one end portion connected to the V-phase terminal  16  to another end portion. Furthermore, the W-phase coil  38 , to which the W-phase terminal  18  is connected, is composed of first and second coils W 1 , W 2 , which are connected in series from one end portion connected to the W-phase terminal  18  to another end portion. 
         [0022]    On the other hand, the other end ports of the U-phase coil  34 , the V-phase coil  36 , and the W-phase coil  38  are connected respectively to a neutral point  40 . More specifically, the U-phase coil  34 , the V-phase coil  36 , and the W-phase coil  38  of the conductors  26  form a Y-shaped connection together mutually. 
         [0023]    In addition, in the U-phase coil  34 , the V-phase coil  36 , and the W-phase coil  38 , the voltages of first coils U 1 , V 1 , W 1  thereof, which are arranged on sides of the U-phase terminal  14 , the V-phase terminal  16 , and the W-phase terminal  18 , to which power is supplied, are comparatively high, whereas the voltages of the second coils U 2 , V 2 , W 2  on the side of the neutral point  40  are relatively lower. 
         [0024]    For the above-described conductors  26 , instead of using the divided conductors  28 , coil windings or the like may also be used. 
         [0025]    Next, a description will be given with reference to  FIG. 3  concerning the arrangement of the conductors  26  in the respective slots of the stator  12 . In the following description, among the 3-phase coils that make up the conductors  26 , the arrangement of the U-phase coil  34  and the V-phase coil  36  will be described in detail, whereas a description concerning the arrangement of the W-phase coils  38  will be omitted. Further,  FIG. 3 , is a schematic illustration in which a cross-sectional surface perpendicular to the axial direction (in the directions of the arrow A) of the stator  12  is laid out, and with reference to  FIG. 3 , a case will be described in which plural slots  24  are disposed from a left side to a right side of the figure (in the direction of the arrow B), and the conductors  26  are wound sequentially in a winding direction toward the right side. 
         [0026]    The arrows that point upwardly and downwardly in the central lower portion of the figure illustrate the positions and orientations of magnetic poles  42   a  to  42   d  in a non-illustrated rotor. The U-phase coils  34  are shown by the dashed line, whereas the V-phase coils  36  are shown by the solid line. 
         [0027]    At first, as shown in  FIG. 3 , the U-phase coil  34  (shown by the dashed line in  FIG. 3 ) is inserted into the first slot  24   a  from the other end surface  20   b  side of the stator core  20 , and after being inserted therethrough to the one end surface  20   a  side of the stator core  20 , the U-phase coil  34  skips over five adjacent ones of the slots  24  in the winding direction (the direction of the arrow B) with respect to the first slot  24   a  along the one end surface  20   a  side, is inserted into the third slot  24   c , and passes therethrough to the other end surface  20   b  side. More specifically, the U-phase coil  34  is inserted into the first and third slots  24   a ,  24   c , and a substantially U-shaped wave winding  46  is constituted thereby, including a crossover region  44  that crosses over the one end surface  20   a  side of the stator core  20 . 
         [0028]    Next, the U-phase coil  34  skips over six adjacent ones of the slots  24  in the winding direction (the direction of the arrow B) with respect to the third slot  24   c , is inserted into the sixth slot  24   f , and passes therethrough to the one end surface  20   a  side. Thereafter, the U-phase coil  34  skips over five of the slots  24  in an opposite direction (the direction of the arrow C) to the winding direction (the direction of the arrow B), and is inserted into the fourth slot  24   d.    
         [0029]    In addition, the U-phase coil  34  skips over six of the slots  24  again in the winding direction (the direction of the arrow B) from the other end surface  20   b  side of the fourth slot  24   d , and is inserted into the seventh slot  24   g  adjacent to the sixth slot  24   f . More specifically, concerning the U-phase coil  34 , a lap winding  48  is constituted thereby, which is wound by one turn in covering relation to the one end surface  20   a  and the other end surface  20   b  of the stator core  20 . In the lap winding  48 , a pair of crossover regions  50   a ,  50   b  is formed respectively on the one end surface  20   a  and the other end surface  20   b  of the stator core  20 . 
         [0030]    Further, the U-phase coil  34 , which is inserted into the seventh slot  24   g , skips over five of the slots  24  again in the winding direction (the direction of the arrow B) on the one end surface  20   a  side of the stator core  20 , is inserted into the ninth slot  24   i , and after being inserted therethrough to the other end surface  20   b , the U-phase coil  34  skips over six adjacent ones of the slots  24  in the winding direction (the direction of the arrow B) and is inserted into another non-illustrated slot. 
         [0031]    In the foregoing manner, in the U-phase coil  34 , wave windings  46 , in which the coil is wound across five adjacent ones of the slots  24  on the one end surface  20   a  side of the stator core  20 , and lap windings  48  adjacent to the wave windings  46 , in which the coil is wound around the one end surface  20   a  and the other end surface  20   b  of the stator core  20 , and with respect to the slots  24  of the adjacent wave windings  46 , the coil is wound across five of the slots  24  on the one end surface  20   a  side and is wound across six of the slots  24  on the other end surface  20   b  side, are arranged alternately along the winding direction (in the direction of the arrow B). 
         [0032]    Stated otherwise, the wave windings  46  of the U-phase coil  34  are wound at a 5-slot pitch along the winding direction (the direction of the arrow B) on the stator core  20 , whereas the lap windings  48  are wound at a 5-slot pitch on the one end surface  20   a  side of the stator core  20 , and at a 6-slot pitch on the other end surface  20   b  side of the stator core  20 . 
         [0033]    On the other hand, the V-phase coil  36  (shown by the solid line in  FIG. 3 ) is inserted, from the other end surface  20   b  side of the stator core  20 , into the second slot  24   b , which lies adjacently in the winding direction (the direction of the arrow B) with respect to the first slot  24   a  in which the U-phase coil  34  is arranged, and after being inserted therethrough to the one end surface  20   a  side of the stator core  20 , the V-phase coil  36  skips over five adjacent ones of the slots  24  in the winding direction (the direction of the arrow B) with respect to the second slot  24   b  along the one end surface  20   a  side, is inserted into the fourth slot  24   d , and passes therethrough to the other end surface  20   b  side. 
         [0034]    More specifically, the V-phase coil  36  is inserted into the second and fourth slots  24   b ,  24   d , and a substantially U-shaped wave winding  54  is constituted thereby, including a crossover region  52  that crosses over the one end surface  20   a  side of the stator core  20 . 
         [0035]    Next, the V-phase coil  36  skips over six adjacent ones of the slots  24  in the winding direction (the direction of the arrow B) with respect to the fourth slot  24   d , is inserted into the seventh slot  24   g  and passes therethrough to the one end surface  20   a  side, and thereafter, the V-phase coil  36  skips over five of the slots  24  in an opposite direction (the direction of the arrow C) to the winding direction (the direction of the arrow B), and is inserted into the fifth slot  24   e . In addition, the V-phase coil  36  skips over six of the slots  24  again in the winding direction (the direction of the arrow B) from the other end surface  20   b  side of the fifth slot  24   e , and is inserted into the eighth slot  24   h.    
         [0036]    More specifically, concerning the V-phase coil  36 , a lap winding  56  is constituted thereby, which is wound by one turn in covering relation to the one end surface  20   a  and the other end surface  20   b  of the stator core  20 . In the lap winding  56 , a pair of crossover regions  58   a ,  58   b  is formed respectively on the one end surface  20   a  and the other end surface  20   b  of the stator core  20 . 
         [0037]    Further, the V-phase coil  36 , which is inserted into the eighth slot  24   h , skips over five of the slots  24  again in the winding direction (the direction of the arrow B) on the one end surface  20   a  side of the stator core  20 , is inserted into the tenth slot  24   j , and after being inserted therethrough to the other end surface  20   b , the V-phase coil  36  skips over six adjacent ones of the slots  24  in the winding direction (the direction of the arrow B) and is inserted into another non-illustrated slot. 
         [0038]    In the foregoing manner, in the V-phase coil  36 , wave windings  54 , in which the coil is wound across five adjacent ones of the slots  24  on the one end surface  20   a  side of the stator core  20 , and lap windings  56  adjacent to the wave windings  54 , in which the coil is wound around the one end surface  20   a  and the other end surface  20   b  of the stator core  20 , and with respect to the slots  24  of the adjacent wave windings  54 , the coil is wound across five of the slots  24  on the one end surface  20   a  side and is wound across six of the slots  24  on the other end surface  20   b  side, are arranged alternately along the winding direction (in the direction of the arrow B). 
         [0039]    Stated otherwise, wave windings  54  of the V-phase coil  36  are wound at a 5-slot pitch along the winding direction (the direction of the arrow B) on the stator core  20 , whereas the lap windings  56  are wound at a 5-slot pitch on the one end surface  20   a  side of the stator core  20 , and at a 6-slot pitch on the other end surface  20   b  side of the stator core  20 . 
         [0040]    Further, in the fourth slot  24   d  and the seventh slot  24   g , both the U-phase coil  34  and the V-phase coil  36 , which are of different phases, are arranged together therein, thereby providing a two-layer winding configuration. 
         [0041]    Similar to the cases of the U-phase coil  34  and the V-phase coil  36 , for example, a W-phase coil  38  is provided in the slot adjacent to the second slot  24   b , and wave windings, lap windings, and wave windings again are arranged alternately along the winding direction (the direction of the arrow B). 
         [0042]    Further, in the above description, a configuration has been described in which, in the wave windings  46 ,  54 , crossover regions  44 ,  52  are formed on the one end surface  20   a  side of the stator core  20 . However, a configuration may also be provided in which such crossover regions are formed on the other end surface  20   b  side of the stator core  20 . 
         [0043]    Furthermore, in the above description, a case has been described in which, concerning the arrangement of the U-phase coil  34  and the V-phase coil  36 , coils are utilized as the conductors  26 . However, instead of such coils, in the event that divided conductors  28  are used as the conductors  26 , the crossover regions  44 ,  50   a ,  52 ,  58   a  on the one end surface  20   a  and the other end surface  20   b  of the stator core  20  may be arranged so as to form the top portions  32  of the divided conductors  28 , and regions that are inserted through the respective slots  24  may constitute the straight line portions  30   a ,  30   b , and ends of the respective divided conductors  28 , which are arranged adjacently, may be connected together electrically. 
         [0044]    The winding direction (the direction of the arrow B) of the conductors  26  in the aforementioned stator  12  is in the same direction as the pitch direction of the slots  24 . 
         [0045]    Further, as shown in  FIG. 4 , in the first, the fourth, the seventh, and the tenth slots  24   a ,  24   d ,  24   g ,  24   j  of the stator  12 , the U-phase coil  34  and the V-phase coil  36 , which are of different phases, are arranged together in the same slots. In this case, in the U-phase coil  34  and the V-phase coil  36 , second coils U 2 , V 2 , which are disposed on the side of the neutral point  40 , are arranged together respectively, and the second coil V 2  is disposed inside of the slots  24  on an outer circumferential side with respect to the second coil U 2 . 
         [0046]    On the other hand, in the third, the sixth, and the ninth slots  24   c ,  24   f ,  24   i , only the U-phase coil  34  is arranged therein, and in this case, only the first coil U 1 , which is disposed on the side of the U-phase terminal  14 , is arranged in the U-phase coil  34 . Further, in the second, the fifth, the eighth, and the eleventh slots  24   b ,  24   e ,  24   h ,  24   k  only the V-phase coil  36  is arranged therein, and in this case, only the first coil V 1 , which is disposed on the side of the V-phase terminal  16 , is arranged in the V-phase coil  36 . 
         [0047]    In the foregoing manner, according to the present embodiment, when the conductors  26  are installed with respect to the plural slots  24  that are formed in the stator core  20 , the U-phase coil  34 , the V-phase coil  36 , and the W-phase coil  38 , which are of different phases, are inserted and wound initially in mutually different adjacent slots  24 . Together therewith, wave windings  46 ,  54  having crossover regions  44 ,  52  only on the one end surface  20   a  side of the stator core  20 , and lap windings  48 ,  56 , in which pairs of crossover regions  50   a ,  50   b ,  58   a ,  58   b  are formed by being wound, respectively, on the one end surface  20   a  and the other end surface  20   b  of the stator core  20 , are arranged in the circumferential direction of the stator core  20 , and more specifically, are arranged alternately along the winding direction (in the direction of the arrow B) of the U-phase coil  34 , the V-phase coil  36 , and the W-phase coil  38 . 
         [0048]    Consequently, windings can be provided in which, on the one end surface  20   a  side of the stator core  20 , the pitch of the conductors  26  (i.e., the distance along the winding direction) is shorter than on the other end surface  20   b  side. Therefore, the conductors  26  are wound alternately in a positive direction and a reverse direction with respect to the winding direction (the direction of the arrow B) of the conductors  26 , and together therewith, the occurrence of shifting or offset between the pitch of the conductors  26  and the pitch of the magnetic poles  42   a  to  42   d  is prevented. 
         [0049]    More specifically, compared to the two-layer winding structure of the rotary electric machine according to the conventional technology, even in the event that the winding pitch of the conductors  26  is shortened, shifting or offset of the winding pitch with respect to the pitch of the magnetic poles  42   a  to  42   d  can be prevented, and the rotary electric machine  10  can be driven smoothly to obtain a desired output. 
         [0050]    Further, by shortening the pitch of the conductors  26 , the height H (see  FIG. 3 ) can be suppressed in the crossover regions  44 ,  50   a ,  50   b ,  52 ,  58   a ,  58   b  on the one end surface  20   a  and the other end surface  20   b  of the stator core  20 , and the dimension in the axial directions of the arrow A of the rotary electric machine  10  including the stator core  20  can be minimized. 
         [0051]    Furthermore, when any two of the U-phase coil  34 , the V-phase coil  36 , and the W-phase coil  38  are arranged with respect to the same slot, as is the case in the fourth, the seventh, and the tenth slots  24   d ,  24   g ,  24   j  in the stator core  20 , the second coils U 2 , V 2 , W 2 , which are of a low voltage and are arranged on the side of the neutral point  40  in  FIG. 2 , may be disposed adjacently alongside one another. Accordingly, the insulation compensation level of the insulating members disposed between coils of different phases can be suppressed. 
         [0052]    Further still, by utilizing the divided conductors  28  as the conductors  26 , the straight line portions  30   a ,  30   b  on open sides thereof can be assembled easily with respect to the stator  12  simply by being inserted into respective slots  24 . In addition, since the top portions  32  can be configured as the crossover regions  44 ,  50   a ,  52 ,  58   a  without requiring any changes thereto, ease of assembly of the conductors  26  can be enhanced. 
         [0053]    Further, the conductors  26  are not limited to the above-described case in which the U-phase coil  34  and the V-phase coil  36  of different phases are wound with a 1-slot offset therebetween in adjacent slots  24  along the winding direction (the direction of the arrows B). For example, as in a stator  100  shown in  FIG. 5 , the second coils U 2 , which are of the same phase, may be arranged on the inner side of the first coils U 1  of the U-phase coil  34 . In  FIG. 5 , the first coils U 1  are illustrated by solid lines, and the second coils U 2  are illustrated by dashed lines. 
         [0054]    At first, in the stator core  20 , the first coil U 1  (shown by the solid line in  FIG. 5 ) is inserted into the first slot  24   a , and after being inserted therethrough from the other end surface  20   b  to the one end surface  20   a  side of the stator core  20 , the first coil U 1  skips over six adjacent ones of the slots  24  in the winding direction (the direction of the arrow B) with respect to the first slot  24   a  along the one end surface  20   a  side, is inserted into the fourth slot  24   d , and passes therethrough to the other end surface  20   b  side. 
         [0055]    More specifically, the first coil U 1  is inserted into the first and fourth slots  24   a ,  24   d , and a first wave winding  104  is constituted thereby including a crossover region  102  that crosses over the one end surface  20   a  side of the stator core  20 . 
         [0056]    The first coil U 1  skips over six adjacent ones of the slots  24  in the winding direction (the direction of the arrow B) the other end surface  20   b  side with respect to the fourth slot  24   d  on the fourth slot  24   d  side, is inserted into the seventh slot  24   g , and passes therethrough to the one end surface  20   a  side, and thereafter, the first coil U 1  skips over six of the slots  24  in an opposite direction (the direction of the arrow C) to the winding direction (the direction of the arrow B), and is inserted into the fourth slot  24   d.    
         [0057]    In addition, the first coil U 1  skips over six of the slots  24  again in the winding direction (the direction of the arrow B) from the other end surface  20   b  side of the fourth slot  24   d , and is inserted into the seventh slot  24   g . More specifically, concerning the first coil U 1 , a first lap winding  106  is constituted thereby, which is wound by one turn in covering relation to the one end surface  20   a  and the other end surface  20   b  of the stator core  20 . 
         [0058]    Further, the first coil U 1 , which is inserted into the seventh slot  24   g , skips over six of the slots  24  again in the winding direction (the direction of the arrow B) on the one end surface  20   a  side of the stator core  20 , is inserted into the tenth slot  24   j , and after having made another first wave winding  104  by being inserted therethrough to the other end surface  20   b , the first coil U 1  skips over six adjacent ones of the slots  24  in the winding direction (the direction of the arrow B), is inserted into another non-illustrated slot, and another first lap winding  106  is made. 
         [0059]    In the foregoing manner, in the first coil U 1 , first wave windings  104 , in which the coil is wound across six adjacent ones of the slots  24  on the one end surface  20   a  side of the stator core  20 , and first lap windings  106  adjacent to the first wave windings  104 , in which the coil is wound around the one end surface  20   a  and the other end surface  20   b  of the stator core  20 , and with respect to the slots  24  of the adjacent first wave windings  104 , the coil is wound across six of the slots  24  on the one end surface  20   a  side and is wound across six of the slots  24  on the other end surface  20   b  side, are arranged alternately along the winding direction (in the direction of the arrow B). The first lap winding  106  includes a pair of crossover regions  108   a ,  108   b.    
         [0060]    More specifically, the first coil U 1  is wound on the stator core  20  at a 6-slot pitch along the winding direction (in the direction of the arrow B). 
         [0061]    On the other hand, the second coil U 2  is inserted, from the other end surface  20   b  side of the stator  100 , into the second slot  24   b , which lies adjacently in the winding direction (the direction of the arrow B) with respect to the first slot  24   a  in which the first coil U 1  is arranged, and after being inserted therethrough to the one end surface  20   a  side of the stator  100 , the second coil U 2  skips over four adjacent ones of the slots  24  in the winding direction (the direction of the arrow B) with respect to the second slot  24   b  along the one end surface  20   a  side, is inserted into the third slot  24   c , and passes therethrough to the other end surface  20   b  side. More specifically, the second coil U 2  is inserted into the second and third slots  24   b ,  24   c , and a second wave winding  112  is constituted thereby, including a crossover region  110  that crosses over the one end surface  20   a  side of the stator  100 . In addition, the slot pitch of the second wave winding  112  is formed with a 4-slot pitch, which is smaller than that of the first wave winding  104 , which is formed with a 6-slot pitch. 
         [0062]    Stated otherwise, the second wave windings  112  are arranged inside of the first wave windings  104 . 
         [0063]    Next, the second coil U 2  skips over six adjacent ones of the slots  24  in the winding direction (the direction of the arrow B) with respect to the third slot  24   c , is inserted into the sixth slot  24   f  and passes therethrough to the one end surface  20   a  side, and thereafter, the second coil U 2  skips over four of the slots  24  in an opposite direction (the direction of the arrow C) to the winding direction (the direction of the arrow B), and is inserted into the fifth slot  24   e . In addition, the second coil U 2  skips over six of the slots  24  again in the winding direction (the direction of the arrow B) from the other end surface  20   b  side of the fifth slot  24   e , and is inserted into the adjacent eighth slot  24   h . More specifically, concerning the second coil U 2 , a second lap winding  114  is constituted thereby, which is wound by one turn in covering relation to the one end surface  20   a  and the other end surface  20   b  of the stator  100 . 
         [0064]    The second lap winding  114  is formed with a 4-slot pitch, which is smaller than that of the first lap winding  106  that is formed with a 6-slot pitch, and the second lap winding  114  includes a pair of crossover regions  116   a ,  116   b , both of which are arranged inside of the first lap winding  106 . 
         [0065]    Further, the second coil U 2 , which is inserted into the eighth slot  24   h , skips over four of the slots  24  again in the winding direction (the direction of the arrow B) on the one end surface  20   a  side of the stator core  20 , is inserted into the ninth slot  24   i , and after having made another second wave winding  112  by being inserted therethrough to the other end surface  20   b , the second coil U 2  skips over six adjacent ones of the slots  24  in the winding direction (the direction of the arrow B), is inserted into another non-illustrated slot, and another second lap winding  114  is made. 
         [0066]    In the foregoing manner, in the second coil U 2 , second wave windings  112 , in which the coil is wound across four adjacent ones of the slots  24  on the one end surface  20   a  side of the stator core  20 , and second lap windings  114  adjacent to the second wave windings  112 , in which the coil is wound around the one end surface  20   a  and the other end surface  20   b  of the stator core  20 , and with respect to the slots  24  of the adjacent second wave windings  112 , the coil is wound across four of the slots  24  on the one end surface  20   a  side and is wound across six of the slots  24  on the other end surface  20   b  side, are arranged alternately along the winding direction (in the direction of the arrow B). 
         [0067]    Further, although with the fourth, the seventh, and the tenth slots  24   d ,  24   g ,  24   j , respective first coils U 1  of a high voltage are disposed together, since the first coils U 1  are of the same phase, there is no need to provide an insulating material therebetween. On the other hand, with respect to slots in which only the second coils U 2  are arranged, as in the case of the second, the third, the fifth, the sixth, the eighth, the ninth, and the eleventh slots  24   b ,  24   c ,  24   e ,  24   f ,  24   h ,  24   i ,  24   k , two-layer windings are provided therein in which the second coils V 2 , W 2  of different phases are arranged. At this time, even though the second coils U 2  of different phases are disposed together in the same slots, since the voltages of the second coils U 2 , V 2 , W 2  are lower than those of the first coils U 1 , V 1 , W 1 , the insulation compensation level of the insulating material provided between the second coils U 2  of one phase and the second coils V 2 , W 2  of other phases can be suppressed. 
         [0068]    Further, although in the above description, a case has been described in which the U-phase coil  34  is arranged from among the three phases, since the same arrangements also apply to the cases of the V-phase coil  36  and the W-phase coil  38 , detailed descriptions of such cases are omitted. 
         [0069]    With the stator  100  according to the modification, since among the U-phase coil  34 , the V-phase coil  36 , and the W-phase coil  38 , which are of the same phase, the second coils U 2  (V 2 , W 2 ) can be arranged in proximity on the inner side of the first coils U 1  (V 1 , W 1 ), compared to the rotary electric machine  10  of the aforementioned main embodiment, the crossover height H (see  FIG. 5 ) of the conductors  26  on the side of the one end surface  20   a  of the stator  100  can be further suppressed, the axial dimension of the rotary electric machine  10  including the stator  100  is reduced, and the rotary electric machine  10  can be made still smaller in size. 
         [0070]    The rotary electric machine according to the present invention is not limited to the above embodiment, and various additional or modified structures may be adopted therein without departing from the scope and essence of the invention as set forth in the appended claims.