Patent Publication Number: US-2009218905-A1

Title: Coil fixing member and electric rotary machine

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is related to and claims priority from Japanese Patent Application No. 2008-49922 filed on Feb. 29, 2008, the contents of which are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the invention 
     The present invention relates to coil fixing members capable of suppressing a displacement between the stator core and the stator coil of an electric rotary machine, and also relates to electric rotary machines having the stator core, the stator coil, and one or more coil fixing members assembled between the stator core and the stator coil. 
     2. Description of the Related Art 
     Recently, there is a strong demand to provide electric rotary machines such as electric motors and alternators with an improved quality, a high electric power, and a small size. For example, the electric rotary machine with a high electric power is assembled in the engine compartment. The area of the engine compartment of the vehicle tends to be reduced according to the above recent demand. Thus, there is the strong demand to improve the reliability of the electric rotary machine. 
     Japanese patent laid open publication No. JP 2000-166158 has disclosed a conventional technique of the electric rotary machine equipped with insulation spacers. Those insulation spacers are placed between the stator core and the stator coil of the electric rotary machine. However, those insulation spacers are only placed between them in the electric rotary machine without being supported by the stator core and the stator coil. This conventional structure of the electric rotary machine often causes shifting of the insulation spacers between the stator core and the stator coil. The insulation spacers finally fall away or release from the stator core by vibration, thermal stress, or mechanical stress caused when the electric rotary machine is rotating. 
     Falling away of the insulation spacers from the stator core causes the electrical contact between the stator core and the stator coil. This causes the deterioration of the insulating function of the stator winding wound on the stator core. The deterioration of the stator winding and the stress by the vibration causes damage to the stator winding. As a result, the damage to the stator core reduces the reliability of the electric rotary machine. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide coil fixing members, and an electric rotary machine with the coil fixing members. In particular, each coil fixing member, to be placed between the stator coil and the stator core of the electric rotary machine, is hard to slip or shift, and finally fall away from the stator core. 
     To achieve the above purposes, the present invention provides a coil fixing member to be inserted and placed between a stator coil and at least one end surface of a stator core in an electric rotary machine having a rotor with a plurality of magnetic north and south poles alternately placed along the circumferential direction thereof. Each coil fixing member suppresses a displacement between the stator core and the stator coil and fixing them together. The stator core has a plurality of slots formed along the circumferential direction of the stator core. The direction in depth of each slot is equal to the diameter direction of the stator core. The slots face together at the inside or the outside. The stator coil has stator windings. Each stator winding has connection parts. Each connection part connects the stator windings in slot accommodation parts together at the outside of the slots. The slot accommodation parts are placed in different slots in the circumferential direction of the stator core. Each coil fixing member has a primary fixing member and a secondary fixing member. The primary fixing member has a wedge-plate shape and has a support part at one side of the circumferential direction of the stator core. The primary fixing member is inserted from the outer side of the diameter direction of the stator core toward the inner side thereof between the end surface of the stator core and the connection parts of the windings of the stator coil. The support part is capable of supporting the connection part of the winding of the stator core. The secondary fixing member of a rod shape is placed at the other side of the primary fixing member. The secondary fixing member is inserted from the inner side of the diameter direction of the stator core toward the outer side thereof between the connection parts of the windings of the stator coil and the end surface of the stator core. 
     The coil fixing member according to the present invention is composed of the primary fixing member and the secondary fixing member which are inserted respectively from opposite directions in the diameter direction of the stator core. The structure of the coil fixing member suppresses the first fixing member and the second fixing member from shifting to each other. One or more coil fixing members are placed between the stator coil and the stator core in order to also suppress the stator coil from shifting to the stator core. This structure prevents the coil fixing members placed between the stator coil from falling away from the stator coil and the stator core in the electric rotary machine even if vibration, heat energy, and mechanical stress are applied to the electric rotary machine. Therefore assembling the coil fixing members according to the present invention into the electric rotary machine suppresses deterioration of the function of the electric rotary machine. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A preferred, non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which: 
         FIG. 1  is a perspective view of the structure of a coil fixing member to be assembled into the stator coil and the stator core of an electric rotary machine according to the embodiment of the present invention; 
         FIG. 2  is a perspective view of a primary fixing member of the coil fixing member according to the embodiment of the present invention; 
         FIG. 3  is a perspective view of a secondary fixing member of the coil fixing member according to the embodiment of the present invention; 
         FIG. 4  is an enlarged view of an assembled state of the stator coil and the stator core in the electric rotary machine according to the embodiment of the present invention; 
         FIG. 5  is an enlarged view of an assembled state of the primary coil fixing member in the coil fixing member between the stator coil and the stator core of the electric rotary machine according to the embodiment of the present invention; 
         FIG. 6  is an enlarged view of an assembled state of the primary coil fixing member and the secondary coil fixing member of the coil fixing member between the stator coil and the stator core in the electric rotary machine according to the embodiment of the present invention; 
         FIG. 7  is a cross section of the electric rotary machine to which the coil fixing members according to the embodiment of the present invention are assembled; 
         FIG. 8A  and  FIG. 8B  each shows a cross section of each phase winding that forms the stator coil of the electric rotary machine according to the embodiment of the present invention; and 
         FIG. 9  is a view showing a star connection (Y-connection) of three phase (U, V, and W phases) windings in the electric rotary machine according to the embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, various embodiments of the present invention will be described with reference to the accompanying drawings. In the following description of the various embodiments, like reference characters or numerals designate like or equivalent component parts throughout the several diagrams. 
     Embodiment 
     A description will be given of the coil fixing member according to an embodiment of the present invention with reference to  FIG. 1  to  FIG. 9 . 
     The coil fixing members according to the embodiment of the present invention are applied to the electric rotary machine  1  with the rotor  2  and the stator  3 . The stator  3  has the stator coil  4  and the stator core  30 . 
       FIG. 1  is a perspective view of a structure of the coil fixing member  5  to be assembled between the stator coil  4  and the stator core  30  of an electric rotary machine  1  according to the embodiment of the present invention.  FIG. 2  is a perspective view of a primary fixing member  51  of the coil fixing member  5  according to the embodiment.  FIG. 3  is a perspective view of a secondary fixing member  52  of the coil fixing member  5  according to the embodiment. As shown in  FIG. 1  to  FIG. 3 , the coil fixing member  5  is comprised of the primary coil fixing member  51  and the secondary coil fixing member  52 . 
     The surface of each corner of the primary coil fixing member  51  and the secondary coil fixing member  52 , which is the opposite side to the stator core  30  when it is placed between the stator coil  4  and the stator core  30 , has a smoothly tapered and rounded shape. 
     As shown in  FIG. 2 , the primary coil fixing member  51  is composed of a main body part  510  of a wedge-plate shape and a stopper part  511 . The main body part  510  and the stopper part  511  are assembled together. The stopper part  511  is formed at an end part of the main body part  510  of the wedge shape. Thus, the stopper part  511  projects toward a wide direction of the main body part  511 . 
     A support part  512  is formed at the side surface of the main body part  510  in the wide direction thereof. The support part  512  supports the windings  40  forming connection parts  45  of the stator coil  4 . The support part  512  is the surface of the main body part  510  and has concave and convex parts which approximately correspond to the windings  40  which form the connection parts  45 . 
     As shown in  FIG. 3 , the primary coil fixing member  51  is a bar member composed of a base end part  520 , a thin thickness part  521 , and a claw part (or a lock part)  522 . 
     The base end part  520  is a member, the cross section of which has a fan shape. The base end part  520  is to be placed at the inner side of the diameter direction of the stator core  30  between the stator coil  4  and the stator core  30 . 
     The thin thickness part  521  and the base end part  520  are assembled together. The thin thickness part  521  is a plate member extending from the base end part  520  toward the diameter direction of the stator core  30 . The thin thickness part  521  is to be placed to form a gap between the thin thickness part  521  and the end surface of the stator core  30 . 
     The claw part  522  is formed at the front end part of the thin thickness part  521  to project toward the opposite direction of the stator core  30 . The claw part  522  is contacted with the connection part  45  of the winding  40  of the stator coil  4  when the secondary coil fixing member  52  is placed between the stator coil  4  and the stator core  30 . The claw part  522  is locked by the connection part  45  of the winding  40  of the stator coil  4 . This structure prevents the secondary coil fixing member  52  from releasing and falling away toward the diameter direction of the stator core  30 . 
       FIG. 4  is an enlarged view of an assembled state of the stator coil  4  and the stator core  30  in the electric rotary machine  1  according to the embodiment of the present invention.  FIG. 5  is an enlarged view of an assembled state of the primary coil fixing member  51  in the coil fixing member  5  between the stator coil  4  and the stator core  30  of the electric rotary machine  1  according to the embodiment of the present invention.  FIG. 6  is an enlarged view of an assembled state of the primary coil fixing member  51  and the secondary coil fixing member  52  of the coil fixing member  5  between the stator coil  4  and the stator core  30  in the electric rotary machine  1  according to the embodiment of the present invention. 
     As shown in  FIG. 47  the coil fixing member  5  of the embodiment is used as a fixing member to be inserted into a gap between the end surface of the stator core  30  and the connection parts  45  of the windings  40  of the stator coil  4 . 
     That is, the primary coil fixing member  51  is inserted from the outside of the diameter direction toward the inside thereof into the gap between the end surface of the stator core  30  and the connection parts  45  of the windings  40  of the stator coil  4 . This insertion of the primary coil fixing member  51  is performed so that the primary coil fixing member  51  is inserted into a central part between a pair of slots  31  shown in  FIG. 4 . 
     When the primary coil fixing member  51  is correctly placed at a predetermined position between the connection parts  45  and the stator coil  30 , the primary coil fixing member  51  is shifted toward the other side of the wide direction of the main body part  510  in order to engage it with the connection parts  45  of the winding  40  of the stator coil  4 . 
     As shown in  FIG. 5 , after the support part  512  engages with the connection parts  45 , the primary coil fixing member  51  is fixed in the gap formed between the connection parts  45  of the windings  40  of the stator coil  4  and the stator core  30 . This structure limits the windings  40  with the connection parts  45  contacted with the support part  512  of the main body part  510  to shift toward the axial direction of the stator core  30   
     After the above assembling of the primary coil fixing member  51  into the connection parts  45  and the stator core  30 , the secondary coil fixing member  52  is inserted, from the inside of the diameter direction of the stator core  30  toward the outside thereof into the gap between the connection parts  45  of the windings  40  of the stator core  4  and the end surface of the stator core  30  at the one side of the main body part  510  of the primary coil fixing member  51 . When the secondary coil fixing member  52  is inserted into this gap, the front end part of the thin thickness part  521  is bent toward the direction of the stator coil  30 , and the claw part  522  is pushed, so that the claw part  522  does not influence the connection parts  45  of the windings  40  of the stator coil  4  when the secondary coil fixing member  52  is inserted into the gap. 
     After the secondary coil fixing member  52  is inserted into the gap, when the claw part  522  reaches to the outer periphery side of the stator core  30  in the diameter direction of the stator core  30 , the thin thickness part  521  of the secondary coil fixing member  52 , which is bent toward the direction of the stator core  30  side, is returned to its original shape, namely, to the plate shape from the bent shape. The position of the claw part  522  in the axial direction of the stator core  30  overlaps the connection part  45  of the winding  40  of the stator coil  4 , and the claw part  522  is locked by the connection part  45  shown in  FIG. 6 . At this time, the side surface of the claw part  522  is contacted with the outer periphery of the connection part  45 . As a result, the secondary coil fixing member  52  does not shift toward the diameter direction of the stator core  30  because the claw part  522  is locked by the connection part  45  of the winding  40  of the stator coil  4 . 
     Because the stopper part  511  of the primary coil fixing member  51  is positioned at the outside of the inserted secondary coil fixing member  52  toward the diameter direction of the stator core  30 , the primary coil fixing member  51  limits the secondary coil fixing member  52  to shift toward the outside of the diameter direction of the stator core  30 . 
     As shown in  FIG. 6 , the main body part  510  of the primary coil fixing member  51  and the base end part  520  of the secondary coil fixing member  52  limit the connection parts  45  of the windings  40  of the stator coil  4  to shift toward the circumferential direction of the stator coil  4 . 
     As a result, the coil fixing member  5  according to the embodiment of the present invention avoids the drawback caused by the presence of the gap formed between the connection parts  45  of the windings  40  of the stator coil  4  and the end surface of the stator core  30 , and to tightly fix the stator coil  4  to the stator core  30 . 
     A description will now be given of the electric rotary machine  1  having the stator coil  4  and the stator core  30  to which the coil fixing members  5  are assembled. 
       FIG. 7  is a cross section of the electric rotary machine  1  having the stator core  30  and the stator coil  4  to which the coil fixing members  5  are assembled. 
     As shown in  FIG. 7 , the electric rotary machine  1  is comprised of the housing  10 , the rotor  2 , and the stator  3 . The housing  10  has a pair of housing members  100  and  101  of a cylindrical shape having one bottom base. The housing members  100  and  101  are joined together through opening parts thereof and tightly fixed to each other. The rotor  2  is fixed to the rotary shaft  20  that is supported by the housing  10  through bearings  110  and  111 . The stator  3  is fixed to the housing  10  at the position of the rotor  2  accommodated by the housing  10 . 
     The rotor  2  has a plurality of permanent magnets which are alternately placed along the outer periphery of the rotor  2  in its circumferential direction in order to form different magnetic poles, north (N) pole and south (S) pole. Those magnetic poles face the inner circumferential side of the stator  3 . However, the number of the magnetic poles of the rotor  2  is not limited because the electric rotary machines have different number of the magnetic poles according to applications. The structure of the electric rotary machine  1  shown in  FIG. 7  has the stator of eight magnetic poles (four N poles and four S poles). 
     The stator  3  has the stator core  30 , the three phase coil  4  composed of phase windings, and insulating sheets (not shown) placed between the stator core  30  and the stator coil  4 . 
     The stator core  30  has a circular ring shape in which a plurality of slots  31  (see  FIG. 4 ) is formed along the inner circumference thereof. each slot  31  is formed so that its depth direction is equal to its diameter direction of the stator core  30 . The number of the slots  31  formed in the stator core  30  is two per each phase of the coil  4 . That is, the total number of the slots  31  is forty eight (eight poles×three phases×2=48). 
     The stator core  30  has a predetermined number of divided cores placed along the circumferential direction thereof. In the structure of the electric rotary machine  1  according to the embodiment, its number is twenty four. Each divided core divides one slot  31 . That is, the adjacent divided cores observed along the circumferential direction of the stator core  30  forms one slot  31 . Each divided core is composed of a teeth part extending toward the inner diameter direction and a back core part where the teeth part is formed. 
     The stator core  30  is made of four hundred and ten magnetic steel sheets which are laminated. Each magnetic steel sheet has 0.3 mm thickness. The insulation thin film is formed between the adjacent magnetic steel sheets which are laminated. It is also possible to form the stator core  30  using available metal thin-plates and insulation films instead of the above laminated magnetic steel sheets. 
       FIG. 8A  and  FIG. 8B  each shows a cross section of each phase winding that forms the stator coil  4  of the electric rotary machine  1  according to the embodiment of the present invention; 
     The stator coil  4  is formed by winding a plurality of windings  40  in a predetermined direction. As shown in  FIG. 8A , each winding  40  forming the stator coil  4  is composed of a conductor  41  made of copper and an insulation film  42 . The insulation film  42  is composed of an inner layer  420  and an outer layer  421 . The outer periphery of the conductor  41  is covered with the inner layer  420 . Thus, the inner layer  420  insulates the conductor  41  from the outer layer  421 . 
     The total thickness of the insulation film  42  composed of the inner layer  420  and the outer layer  421  has a thickness within a range of 100 μm to 200 μm. 
     Because the insulation film  42  composed of the inner layer  420  and the outer layer  421  is thick, it is not necessary to insulate the winding  40  from the adjacent winding  40  by an insulator such as an insulation paper between the adjacent windings  40 . However, it is possible to use the insulation paper between the adjacent windings  40  or between the stator core  30  and the windings  40 . 
     The outer layer  421  is made of insulator such as thermoplastic resin or polyamideimide having a higher glass transition temperature rather than that of the outer layer  421 . Using of the above outer layer  421  causes faster softening of the outer layer  421  rather than the inner layer  420  by heat energy generated in the electric rotary machine  1 . The heat energy from the electric rotary machine  1  melts the outer layers  421  of the windings  40  placed in the same slot  31  and the outer layers  421  of the windings  40  in the same slot  31  thermally adhere together. The melted outer layers  421  make the single rigid wire composed of the assembled windings  40 . As a result, because this increases the mechanical strength of the windings  40  placed in each slot  31 , and because the outer layer  421  is firstly separated from the inner layer  420  rather than that the inner layer  420  is separated from the conductor  41  by excess vibration, it is possible to maintain the adhesion force between the inner layer  420  and the conductor  41  in each winding  40 , and to maintain the electrical insulation between the conductor  41 . 
     Still further, as shown in  FIG. 8A  and  FIG. 8B , it is possible to cover the outer periphery of the insulation film  42  composed of the inner layer  420  and the outer layer  421  with melting material  43  such as epoxy resin. 
     Because this structure melts the melting material  43  by heat energy generated in the electric rotary machine  1  faster than the insulation film  42 , the plurality of windings  40  placed in the same slot  31  is melted and adhered to each other. This makes the single rigid wire composed of the assembled windings  40 . As a result, because this increases the mechanical strength of the windings  40  placed in each slot  31 . 
     Still further, it is possible to use the insulation film  42  made of polyphenylenesulfide (PPS) for the windings  40  forming the stator coil  4 . 
       FIG. 9  is a view showing a star connection (Y-connection) of the three phase (U, V, and W phases) windings in the electric rotary machine  1  according to the embodiment of the present invention. 
     As shown in  FIG. 9 , the stator coil  4  consists of the three phase windings. Each phase winding is composed of two components such as U 1  and U 2 , V 1  and V 2 , and W 1  and W 2 . 
     The stator coil  4  consists of the plurality of windings  40  wound in a predetermined loop shape. The windings  40  forming the stator coil  4  are wound at the inner periphery of the stator core  30  along the circumferential direction. The stator core  4  has slot accommodation parts  44  and connection parts  45 . Each slot accommodation part  44  has a straight shape and is placed in the slot  31  formed in the stator core  30 . Each connection part  45  connects the adjacent slot accommodation parts  44  together. 
     Each slot accommodation part  44  is accommodated in the slot  31  every predetermined slot number. In the structure of the embodiment, the predetermined slot number is six (three phases×two=six). 
     Each connection part  45  is projected from the end surface of the stator core  30  in the axial direction of the electric rotary machine  1 . 
     As shown in  FIG. 4 ,  FIG. 5 , and  FIG. 6 , the stator coil  4  consists of the plurality of windings  40  formed along the circumferential direction of the stator core  30  so that one end of each winding  40  projects from the end surface of the stator core  30  and has a wave form. 
     The windings  40  of the stator coil  4  are wound from the outside toward the inside direction of the diameter of the stator core  30 . 
     The end part of each winding  40  projects at the inner circumferential surface from the end surface of the stator coil  4 . 
     The method of winding up the windings  40  of the stator coil  4  is specifically limited. 
     It is possible to make one phase of the stator coil  4  using two windings  40  which are wound in different direction and have a wave form along the circumferential direction of the stator core  30 , and which are connected together at the returning point  46  shown in  FIG. 4 ,  FIG. 5 , and  FIG. 6 . That is, it is acceptable for the winding  40  to consist of the primary winding  40  and the secondary winding  40  electrically connected together. Both the slot accommodation parts  44  for the primary and secondary windings are accommodated in the same slot  31 . The slot accommodation part  44  for the primary winding  40  and the slot accommodation part  44  for the secondary winding  40  are alternately placed in the depth direction of the slot  31 . Because this structure avoids the end part of the winding  40  at the inmost periphery side of the stator coil  4 , and the end part of each winding  40  is not thereby over the end surface of the stator coil  4 , it is possible to reduce the entire size of the stator coil  4 . 
     The end parts of the primary and secondary windings  40  at the inmost periphery side in the stator coil  4  are electrically connected so that both the primary and secondary windings  40  form one phase. The six pairs of the primary and secondary windings  40  form the stator coil  4  of the three phase (U, V, and W)×two slots. That is, the stator coil  4  uses two windings  40  (primary and secondary windings  40 )×three phases (U, V, and W)×two slots=12 (windings in total). 
     In the embodiment of the present invention, the winding  40  is wound four-times to form the stator coil  4 . That is, the stator coil  4  has the four layer structure in the circumferential direction. In other words, the eight slot accommodation parts  44  are placed in one slot  31 . 
     The connection parts  45  of the windings  40  are placed at both sides of the stator core  30  in the axial direction. It is so formed that a central part of the connection part  45  has a crank shape without twisting. The connection part  45  has a crank shape observed along the circumferential direction of the stator core  30 . The shift amount of the connection part  45  having the crank shape is approximately equal to a width of the winding  40 . Because this structure avoids any interference between the connection parts  45  of the adjacent windings  40  in the diameter direction of the stator core  3 , it is possible to closely wind up the connection parts  45  in the stator coil  4 . 
     As a result, because the width of the coil end projected from the end surface of the stator core  30  is reduced, it is possible to avoid the winding  40  forming the stator coil  4  extending toward the outside in the diameter direction of the stator core  30 . 
     The connection part  45  projected from the slot  31  toward the outside of the stator core  30  has a step shape from the end surface of the stator core  30  toward the axial direction of the stator core  30 . Having the step shape of the connection part  45  avoids the interference to the winding  40  projecting from the slot which is adjacent to the connection part  45  along the circumferential direction. This structure prevents the height of the coil end projecting from the end surface of the stator core  30  or the width of the coil end in the diameter direction becoming large in order to eliminate interference between windings together projecting from the slots adjacent along the circumferential direction. As a result, because the height of the coil ends of the stator coil  4  can be decreased, and the width of the coil end of the stator coil  4  in the diameter direction of the stator core  30  becomes small, it is possible to prevent the stator coil  4  from projecting toward the diameter direction of the stator core  30 . 
     The connection part  45  has the four step shape, and the height of one step of the connection part  45  is approximately equal to the width (or height) of the winding  40 . It is thereby possible to overlap the connection parts  45  without any gap when the connection parts  45  are laminated in the axial direction of the stator core  30 . This structure of the connection parts  45  allows the connection parts  45  to be closely wound. 
     The top part (or the highest part) of the step-shaped connection part  45  has a crank-shaped part. Therefore both sides of the connection part  45  of the winding  40  have the step shape toward both sides observed from the crank-shaped part. 
     There is a gap between the bottom part of the connection part  45  of a step shape and the end surface of the stator core  30 . The bottom part of the connection part  45  is a part extending approximately in parallel along the end surface of the stator core  30 . The gap relaxes the stress applied to the stator windings  40  when the windings  40  are processed, the stator coil  4  and the stator core  30  are assembled. The presence of the gap also prevents deterioration of the insulation function, and also the stator core  30  from being deformed. 
     In the stator coil  4 , the connection parts  45  project within the height of the coil end projected from the stator core  30 , and the end part of the assembled body of each winding  40  forming the stator coil  4  projects toward the outside of the diameter direction of the stator core  30 . The end part of each assembled phase winding  40 , that is, the end part of the neutral node of the stator coil  4  projects toward the outside in the diameter direction rather than the end part of the other windings. 
     The present invention does not limit the number of the coil fixing members  5  to be assembled in the electric rotary machine  1 . It is acceptable to fix the coil fixing members  5  at not less than a pair of symmetric positions along the circumferential direction of the stator core  30 . The most preferable number thereof is three. 
     Still further, it is sufficient to fix the coil fixing members  5  onto at least one end surface of the stator core  30  in the electric rotary machine  1 . It is more preferable to fix the coil fixing members  5  onto both the end surface of the stator core  30  in the electric rotary machine  1 . 
     (Other Features and Effects of the Present Invention) 
     In the coil fixing member as another aspect of the present invention the secondary fixing member has a lock part. The lock part locks the outermost peripheral surface of the connection part of the winding of the stator coil in the diameter direction. The secondary fixing member is also locked by the connection part of the winding of the stator coil. This prevents the secondary fixing member from shifting toward the diameter direction of the stator core. 
     In the coil fixing member as another aspect of the present invention, the primary fixing member suppresses the secondary fixing member from shifting toward the outside of the diameter direction of the stator core. The stopper part of the primary fixing member prevents the secondary fixing member from shifting toward the outside of the diameter direction of the stator core. 
     In accordance with another aspect of the present invention, an electric rotary machine has a rotor, a stator, a stator coil, and coil fixing members. The rotor has a plurality of magnetic north and south poles, alternately placed along the circumferential direction thereof. The stator core has a plurality of slots formed on at least one end surface thereof along the circumferential direction. The stator coil has stator windings. Each stator winding has connection parts. Each connection part connects slot accommodation parts together at the outside of the slot. The slot accommodation parts are placed in different slots in the circumferential direction. A plurality of coil fixing members are placed between the stator coil and at least one end surface of the stator core in order to suppress a displacement between the stator coil and the stator core. Each coil fixing member has a primary fixing member and a secondary fixing member. The primary fixing member of a wedge-plate shape has a support part at one side of the circumferential direction of the stator core. The primary fixing member is inserted from the outer side of the diameter direction of the stator core toward the inner side thereof between the connection parts of the windings of the stator coil and the end surface of the stator core. The support part is capable of supporting the connection part of the winding of the stator core. The secondary fixing member of a rod shape is placed at the other side of the primary fixing member The secondary fixing member is inserted from the inner side of the diameter direction of the stator core toward the outer side thereof between the connection parts of the windings of the stator coil and the end surface of the stator core. 
     The coil fixing members make it hard to fall away of or release the stator core even if various types of stress such as mechanical stress, heat stress, and vibration are applied to the coil fixing members and those stresses deform the coil fixing members placed between the stator coil and the end surface of the stator core. That is, the electric rotary machine with the coil fixing members has the improved feature to avoid decreasing of the performance caused by falling away of the coil fixing members from the stator core. 
     While specific embodiments of the present invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limited to the scope of the present invention which is to be given the full breadth of the following claims and all equivalent thereof.