Abstract:
The invention provides a rotating electrical machine provided with stable rotation characteristics for enabling each core to be reliably fixed in arranging a plurality of cores annularly around the rotor even when the dimensional error occurs in manufacturing accuracy of each core, causing each division core itself to enhance the cooling property, and resolving instability of magnetic reluctance between division cores, where the rotating electrical machine has a plurality of stator cores obtained by laminating electromagnetic steel plates, winding coils wound around the stator cores via insulators, a pair of first and second bracket members that hold the plurality of stator cores from the front and back in the rotary shaft direction of the magnet rotor, and a fastening member that couples the first and second bracket members, in the first bracket member is formed a first contact surface for striking one end face of each of the stator cores to regulate so as to arrange the plurality of stator cores annularly, in the second bracket is formed a second contact surface for striking the other end faces of the stator cores to regulate, the first contact surface constitutes a reference plane to align one end faces of the plurality of stator cores on the same plane, the second contact surface is formed of a deformation surface deformable to follow the other end faces of the plurality of stator cores, and at least one of the pair of first and second brackets is formed of a ring-shaped magnetic material for magnetically coupling between the division cores.

Description:
RELATED APPLICATIONS 
     The present application is based on, and claims priorities from, Japanese Applications No. JP2009-070694, filed Mar. 23, 2009 and No. 2009-270901, filed Nov. 30, 2009, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to a stator structure of electromagnetic motors, generators, etc. and rotating electrical machines using the stator structure, and more particularly, to improvements in a fixing structure of a stator provided with coils. 
     Generally, a rotating electrical machine such as a DC motor and generator is comprised of a rotor provided with a rotary shaft and a stator, and in inner rotor type rotating electrical machines, such a structure is widely known that a magneto rotor is rotatably supported axially by a housing and that stator coils are arranged in the shape of a ring around the periphery of the rotor. 
     As shown in  FIG. 10A , a rotating electrical machine is generally known which has an appearance such that a stator core C is nipped in a sandwich form between a pair of end brackets E 1 , E 2  made of die-cast aluminum and that a rotary shaft R 1  protrudes through the center. For example, the stator core C has a shape as shown in  FIG. 10B  as disclosed in Patent Document 1 (Japanese Unexamined Utility Model Publication No. H06-60284). 
     This stator core C is fabricated by layering the necessary number of magnetic plates each obtained by forming a portion to accommodate a rotor R to be rotatable in the center portion, magnetic pole portion C 1 , and a portion where stator coils are wound and arranged in a thin plate material C 2  made of a magnetic material by press working with die-cutting. In addition, the rotor R is comprised of a magnetic rotor R 2  and rotary shaft R 1 . 
     Further, in recent years, for example, Patent Document 2 (Japanese Unexamined Patent Publication No. 2004-266982) discloses an inner rotor type rotating electrical machine where the rotary shaft of the rotor is axially supported by a pair of front and rear cup-shaped brackets, magnets are disposed in the rotor to form NS magnetic poles in the rotation circumference direction, and stator coils are arranged in the shape of a circular ring around the periphery of the rotor. In the Document, a stator coil is wound around each of a plurality of divided cores via an insulator, the plurality of stator coils is held by a pair of cup-shaped brackets from the front and back of the rotary shaft, and circular magnetic teeth are formed. Then, each of a plurality of divided cores annularly arranged is fabricated by press-forming an electromagnetic steel plate, for example, a silicon steel plate into a desired shape, and layering the core pieces in a laminate form, and each stator core is thus prepared. The stator core is covered with an insulator and wound with the core, adjacent cores are fitted in a concavo-convex manner, and annular stator coils are formed. 
     Thus formed ring-shaped stator coils are fixed by a pair of cup-shaped brackets axially supporting the magnet rotor, and a structure of the rotating electrical machine is formed. By axially supporting the rotor rotary shaft by a pair of brackets, the magnet rotor is positioned, a plurality of stator cores is nipped by the pair of brackets, and ring-shaped stator coils are thereby arranged around the periphery of the rotor. 
     As described above, each of a plurality of magnetic pole portions protrudes toward the center in the stator core comprised of a single magnetic plate obtained by performing press working with die-cutting on a thin plate material made of a magnetic material as described previously. Accordingly, it is very difficult to wind the stator coil that is wound around the plurality of magnetic pole portions, and the automatic winding machine for automatically winding the coil is complicated and considerably expensive. 
     Therefore, in order to enable ordinary automatic winding machines to wind the stator coil with ease, each magnetic pole portion of the stator core is formed of a division core that is divided from one another, the stator coil is wound around each division core, and then, division cores are combined to form a single stator core. 
     However, when a stator core is formed of a plurality of division cores, the magnetic reluctance is high in the junction between division cores, a magnetic circuit is hard to form, and magnetic instability thereby occurs and becomes a factor of fluctuations in rotation. 
     Further, in arranging the stator coils around the magnet rotor in the shape of a ring as described previously, for the stator coils, it is general to prepare a plurality of stator cores corresponding to the magnetic teeth to arrange in the shape of a ring. For example, the number of stator cores is defined such that magnetic teeth corresponding to a multiple of 4 are formed in three-phase motors, each stator core is formed such that electromagnetic steel plates such as silicon steel plates are layered in a laminate form, the coil is wound around the periphery via an insulator, and end portions of the stator cores are coupled, for example, in a concavo-convex fit. 
     In the case of such a structure where a plurality of stator cores is coupled annularly to prepare the stator coils, and is sandwiched by a pair of brackets from the front and back of the rotary shaft, the thickness shape of each core becomes a problem. Referring to  FIG. 7 , since each stator core is configured by laminating a plurality of electromagnetic steel plates, it is extremely difficult to manufacture the stator core in a uniform thickness shape. In other words, as shown in  FIG. 9 , assuming that the laminate thickness of a first stator core  91   a  is t 1  and that the laminate thickness of a second stator core  91   b  is t 2 , when the laminate thickness t 1  and laminate thickness t 2  are different from each other, a gap occurs in the struck surface  95   a  of the first bracket and the struck surface  96   a  of the second bracket. When the magnet rotor (not shown) rotates, each stator core rattles back and forth in the shaft direction due to the gap g, and noise and vibrations arise. Concurrently therewith, the magnetic forces of the magnetic teeth formed around the periphery of the rotor change, thereby resulting in a cause of fluctuations in rotation. 
     Therefore, conventionally, when such a plurality of stator cores is prepared, the thickness of the material plate of the electromagnetic steel plate, press-die structure, etc. are devised to uniform the thickness shape of each core, and the uniform thickness is thus secured. For example, when the rolled steel plate undergoes press die-cutting, die-cutting is performed along the rolling direction where fluctuations in material thickness are small, and its manufacturing is thus difficult and becomes a factor of high cost. 
     The present invention was made in view of the above-mentioned problems, and it is a first object of the invention to provide a stator structure and rotating electrical machine without generating noise and vibrations in action for enabling each core to be reliably fixed in arranging a plurality of cores annularly around the rotor to configure a stator even when the dimensional error occurs in manufacturing accuracy of each core. 
     Further, it is a second object of the invention to provide a stator structure and rotating electrical machine for enabling a plurality of cores to be fixed in a precise annular shape in alignment with one another in the shaft direction of the rotary shaft. 
     Furthermore, with attention directed toward a pair of end brackets nipping a stator core in a sandwich form in a rotating electrical machine such that a plurality of division cores is assembled and formed as a single stator core, it is a third object of the invention to provide a rotating electrical machine provided with stable rotation characteristics without fluctuations in rotation, by connecting magnetically division cores to one another using the end brackets and thereby eliminating magnetic instability. 
     BRIEF SUMMARY OF THE INVENTION 
     To attain the above-mentioned objects, in a rotating electrical machine of the invention, a plurality of stator cores each of a predetermined shape obtained by laminating electromagnetic steel plates is prepared corresponding to magnetic teeth, and the cores are nipped by a pair of first and second brackets arranged in the front and back in the rotary shaft direction. At this point, the first bracket member is provided with a first contact surface for striking one end face of a core to regulate, and the second bracket member is provided with a second contact surface for striking the other end face of the core to regulate. Then, the first contact surface constitutes a reference plane for aligning one end faces of a plurality of cores on the same plane, while the second contact surface is formed of a deformation surface deformable to follow the other end faces of the plurality of cores. By this means, the plurality of cores is aligned in their one end faces on the same plane (that is the plane perpendicular to the rotary shaft), while being pressed and supported in the other end faces by the deformation surface that deforms to follow the core dimension (thickness dimension), and is fixed reliably without rattling. The configuration will specifically be described below. 
     In a stator structure of a rotating electrical machine in which a plurality of magnetic teeth is formed around a magnet rotor, provided are a plurality of stator cores each obtained by laminating electromagnetic steel plates, winding coils wound around the stator cores via insulators, respectively, a pair of first and second bracket members that hold the plurality of stator cores from the front and back in the rotary shaft direction of the magnet rotor, and a fastening member that couples the first and second bracket members. In the first bracket member is formed a first contact surface for striking one end face of each of the stator cores to regulate so as to arrange the plurality of stator cores annularly, and in the second bracket is formed a second contact surface for striking the other end face of each of the stator cores to regulate. The first contact surface, constitutes a reference plane to align one end faces of the plurality of stator cores on the same plane, and the second contact surface is formed of a deformation surface deformable to follow the other end faces of the plurality of stator cores. 
     As the aforementioned deformation surface, for example, the second bracket member is formed of a material softer than the electromagnetic steel plates forming the stator cores, and the deformation surface is configured to cause elastic and plastic deformation by a fastening force for fastening the first and second bracket members using the fastening member. 
     Further, the first contact surface is formed in a plane shape coming into surface-contact with the end faces of cores, the second contact surface is formed in an inclined surface coming into line-contact with the end faces of cores, and thus, in fastening the first and second bracket members using the fastening member, the second contact surface deforms and is suited to the thickness shapes of the cores without the first contact surface deforms. 
     Furthermore, the above-mentioned rotating electrical machine has a pair of first and second bracket members opposed to each other, a magnet rotor having a rotary shaft axially supported by the pair of brackets, a stator supported by the pair of brackets to form a plurality of magnetic teeth around the periphery of the magnet rotor, and a fastening member that couples the pair of brackets, where the stator is comprised of a plurality of division cores, each obtained by laminating electromagnetic steel plates, arranged annularly around the magnet rotor, and winding coils wound around the division cores via insulators, respectively, and at least one of the pair of first and second brackets is formed of an annular magnetic material for magnetically coupling between division cores. 
     Still furthermore, outside ends of the plurality of division cores form an external wall of the machine, and part of each of the outside ends protrudes to form a cooling fin. 
     As described above, in the invention, in arranging a plurality of stator cores around the rotor annularly between the first and second bracket members to fix, one end face of each of the stator cores is positioned with reference to the first contact surface formed in the first bracket member, the other end face of each of the cores is fixed by the deformation surface formed in the second bracket that deforms to suit to the core dimension, and therefore, the invention has the effects as described below. 
     In a plurality of stator cores formed by laminating electromagnetic steel plates, their one end faces are regulated in position by the first contact surface and arranged in alignment with one another on the reference plane in the rotary shaft direction, and the other end faces are held by the second contact surface. At this point, the second contact surface deforms in accordance with the core dimension by the fastening force of the fastening member for coupling the first and second bracket members. By this means, the plurality of stator cores is aligned in their one end faces on the reference plane, and is pressed and supported in the other end faces by the deformation surface deforming corresponding to fluctuations in dimensional accuracy. Accordingly, a plurality of stator cores arranged annularly around the magnet rotor is reliably secured and supported between the first and second brackets, and each stator core does not rattle, and eliminates the fear of occurrence of noise and/or vibrations under action. 
     Further, in the invention, the second bracket member forming the deformation surface is made of a material softer than the stator core formed from electromagnetic steel plates, the deformation surface deforms to follow the core dimension by the fastening force of the fastening member, and it is thus possible to reliably fix a plurality of stator cores having dimensional differences without requiring specific processing. 
     Furthermore, the deformation surface is formed in the shape of an inclined positive-cone curbed surface, the vertex of the cone curbed surface is formed in the shape substantially in agreement with the shaft center of the rotary shaft, and it is thereby possible to arrange a plurality of stator cores in the shape of a positive cone with reference to the shaft center of the rotary shaft of the stator core. It is thus possible to bring shaft centers of the rotor and stator cores into agreement with each other. 
     Still furthermore, the invention is capable of providing a rotating electrical machine which is formed as a single stator core by combing a plurality of division cores, where at least one of a pair of end brackets nipping the stator core in a sandwich shape is formed of an annular magnetic material for coupling magnetically between division cores, and the division cores are magnetically connected to one another and thereby resolve magnetic instability, and which has stable rotation characteristics without fluctuations in rotation. 
     Moreover, as a result of coupling between division cores magnetically using the end bracket, the need is eliminated of wrapping and enclosing the division core with a yoke case, and the end faces of the division cores can be configured as an external wall of the machine. Then, by forming a cooling fin partially protruding through the outside end, heat generated inside the machine is spontaneously released with efficiency, and it is possible to reduce a heat loss and increase rotation efficiency. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1A  is an explanatory view of a rotating electrical machine according to the invention and shows a longitudinal cross section; 
         FIG. 1B  is another explanatory view of the rotating electrical machine according to the invention and is a perspective view of a core member; 
         FIG. 1C  is still another explanatory view of the rotating electrical machine according to the invention and is a structural view of a core piece; 
         FIG. 2  is a structural explanatory view of a stator as shown in  FIG. 1 ; 
         FIG. 3A  is an explanatory view showing a structure of a division core and shows a coupling state of the division cores; 
         FIG. 3B  is another explanatory view showing the structure of the division core and is an explanatory view of an angle reference plane of the division core; 
         FIG. 3C  is still another explanatory view showing the structure of the division core and is a positioning configuration view by a first bracket in the division core; 
         FIG. 4A  is an enlarged view of the division core laminate chain-shape bracket support as shown in  FIG. 1A ; 
         FIG. 4B  is another enlarged view of the division core laminate chain-shape bracket support as shown in  FIG. 1A ; 
         FIG. 5A  is an explanatory view showing Embodiment 1 of a second bracket in  FIG. 4B  and shows a longitudinal cross section of the second bracket; 
         FIG. 5B  is another explanatory view showing Embodiment 1 of the second bracket in  FIG. 4B  and is an enlarged view of a second contact surface of the second bracket; 
         FIG. 6  is an explanatory view showing Embodiment 2 of the second bracket different from  FIG. 5B ; 
         FIG. 7A  contains an explanatory view of a magnetic circuit configuration by division cores and brackets; 
         FIG. 7B  contains another explanatory view of a magnetic circuit configuration by division cores and brackets; 
         FIG. 8  is a graph showing characteristic comparison of the rotating electrical machine of the invention; 
         FIG. 9  is an explanatory view showing a conventional fixing structure of a stator core; 
         FIG. 10A  is a perspective view of a conventional rotating electrical machine; and 
         FIG. 10B  is a sectional plan view of the conventional rotating electrical machine. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will specifically be described below based on preferred Embodiments. Described first is a configuration of a rotating electrical machine according to the invention. As shown in  FIG. 1A , a rotating electrical machine (hereinafter, referred to as a motor) M is comprised of a rotor  10 , stator  20 , first bracket  30 , second bracket  40 , and external casing (not shown). The rotating electrical machine M shown in  FIG. 1A  indicates a brushless three-phase DG motor, and the invention will be described below according to the structure. 
     [Rotor Configuration] 
     The rotor  10  is comprised of a rotary shaft  11 , a rotor core  12  integrally formed in the rotary shaft  11 , and magnets  13  formed around the periphery of the rotor core  12 . The rotary shaft  11  is comprised of a rod made of a metal material or the like with strength enduring a rotation load. For example, the rotor core  12  is configured by die-molding ferromagnetic metal powder such as iron powder, and is formed integrally in the rotary shaft  11 . The magnets  13  are embedded around the periphery of the rotor core  12 , and in the rotor shown in the figure, magnetic poles corresponding to a multiple of 3 are formed. As the magnetic poles, N-S poles are arranged alternately at regular intervals around the periphery of the rotor. The magnet  13  is formed from neodymium, ferrite, rare-earth cobalt or the like, and eight poles are arranged at regular intervals (45-degree intervals) around the rotor core  12  with the N poles and S poles alternately arranged. 
     [Stator Configuration] 
     The stator  20  is arranged annularly to surround the periphery of the rotor, and is formed by annularly coupling a plurality of division cores  21  ( 21   a  to  21   l ). Each of division cores  21   a  to  21   l  is wound with a winding coil  23  via an insulator  22 . As described later, the division core  21  is formed by layering electromagnetic steel plates, for example, silicon steel plates obtained by adding silicon to iron, in a laminate form. Generally, a rolling steel plate subjected to rolling processing is cut and formed into a predetermined shape using a press die, and a core piece  21   x  is prepared. Then, a plurality of (for example, 50) core pieces  21   x  is layered in a laminate form to form a core member, the core member is fitted with the insulator  22 , and the winding coil  23  is wound around the core member. The number of turns of the winding coil  23  is beforehand determined from a design value. 
     In this Embodiment as shown in the figure (see  FIG. 2 ), the number of the above-mentioned division cores  21  is “12” (a multiple of 4 from the relationship with the three-phase DC motor), the cores are arranged annularly at 30-degree intervals, and each core piece  21   x  is wound with the winding coil  23   a,    23   b,  . . . , or  23 I via the insulator  22 . In the 12 division cores  21 , mutually opposed winding coils  23  with the same phase are coupled and connected, and three-phase division cores  21   a,    21   e  and  21   i  are connected to input terminals T 1 , T 2  and T 3 , respectively (see  FIG. 2 ). Accordingly, the three-phase division cores  21   a,    21   e  and  21   i  are required to be positioned in precise angle positions at 120-degree intervals around the rotor  10 . 
     [Bracket Configuration] 
     The above-mentioned rotor  10  and stator  20  are fixed by a pair of first bracket  30  and second bracket  40 . This pair of first and second brackets  30  and  40  are coupled to each other by fastening members (coupling belts in the  FIG. 50  as shown in  FIG. 1A , and fix the rotor  10  and stator  20  as described below. First, the rotary shaft  11  of the rotor  10  is supported, in two front and back portions spaced a predetermined distance (distance L), rotatably by a bearing  31  provided in the first bracket  30  and a bearing  41  of the second bracket. Concurrently therewith, the bearings  31  and  41  are provided with steps  32  and  42 , and the steps  32  and  42  regulate in position a positioning step (E-ring)  11   e  formed in the rotary shaft  11 . By this means, the rotor  10  is regulated in position in the radial direction and thrust direction by the first and second brackets  30  and  40 . 
     The above-mentioned first and second brackets  30  and  40  fix the stator  20  as described below. Described first is the structure of the stator  20 . As described previously, the stator  20  is comprised of a plurality of division cores  21   a  to  21   l  (twelve in this Embodiment of the three-phase motor shown in the figure) and each division core is configured by forming an electromagnetic steel plate (for example, silicon steel plate) into an appropriate shape by die-cutting using a press die, and layering core pieces  21   x  in a laminate form. As shown in  FIG. 1C , each of the core pieces  21   x  is formed in cross section in a substantially sector shape, and a plurality of (several tens of) pieces is layered in a laminate form and forms a single division core  21 . 
     Then, a concave portion  21   y  and a convex portion  21   z  are formed in portions adjacent to each other, are fitted with each other, and are thus coupled in the shape of a chain. The core piece  21   x  is provided with a coil winding portion  21   w  and fringe portion  21   v,  and the winding coil  23  is wound around the winding portion  21   w  with the insulator  22  existing therebetween. Further, the fringe portion  21   v  is fixed to the first and second brackets  30  and  40 . 
     Further, in the core piece as shown in the figure, an angle reference plane  21   u  is formed in the core piece  21   x  as shown in  FIG. 3C . The angle reference plane  21   u  shown in the figure is provided in the convex portion formed in the fringe portion  21   v  of the core piece  21   x,  and engages with a positioning protrusion  34  formed in a first contact surface  33  of the first bracket  30  described later. By this means, a plurality of division cores  21   a  to  21   l  mutually coupled in the shape of a circular ring is positioned in angle positions defined by the first bracket  30  described later. 
     Furthermore, the above-mentioned division cores  21  are fixed to the first and second brackets  30  and  40  as described below. In one of the brackets (first bracket  30 ) is formed first contact surfaces  33  each for striking and regulating one end face (Sra shown in  FIG. 4B ) of the division core  21  obtained by layering the core pieces  21  in a laminate form. The first contact surfaces  33  are formed radially in the ring-shaped (circular) first bracket  30  corresponding to the number of division cores  21 . Then, the first contact surface  33  is formed of a plane coming into surface-contact with one end face Sra of the division core  21 . 
     In addition, each fringe portion  21   v,  which forms the convex portion protruding outward from each core piece  21   x,  protrudes from the external wall of the machine, thereby exerts the effect as a cooling fin, and is intended to spontaneously release heat generated inside the machine with efficiency, reduce a heat loss, and increase rotation efficiency. 
     Further, the first bracket  30  is provided with the positioning protrusion  34  for defining in position the angle position (that is the angle position in the rotor rotation direction) of the division core  21 . The positioning protrusion  34  is provided in three portions at 120-degree regular intervals from the relationship that the apparatus shown in the figure is a three-phase motor, and this position is aligned with the angle reference plane  21   u  of the division core  21  as described previously. 
     Meanwhile, in the other bracket (second bracket  40 ) are formed second contact surfaces  43  each for striking and regulating the other end face (Srb shown in  FIG. 4B ) of the division core  21 . The second contact surfaces  43  are also formed radially in the second bracket  40  of annular cross section corresponding to the number of division Cores  21 . With respect to the second contact surfaces  43 , Embodiment 1 is shown in  FIGS. 5A and 5B , and Embodiment 2 is shown in  FIG. 6 . 
     [Configurations of the First and Second Brackets] 
     First, as shown in  FIG. 5A , the first bracket  30  is comprised of a structure such that a bracket cover  30   a  formed by aluminum die-cast is fitted with an annular ring body (first magnetic member)  30   b  made of a magnetic material coming into contact with the bottoms of the division cores  21  to hold. The annular ring body  30   b  forms magnetic loops with the division cores  21  to form the machine external wall portion so as to obtain the cooling effect, thereby intending magnetic stabilization of the division cores  21 . Similarly, the second bracket  40  is comprised of a structure such that a bracket cover  40   a  formed by aluminum die-cast is fitted with an annular ring body (second magnetic member)  40   b  made of a magnetic material in a position facing the tops of the division cores  21 . This annular ring body  40   b  is spaced a distance apart from the division cores  21  in a position which does not undergo the effect of fluctuations in dimension among the division cores  21  to form the machine external wall portion so as to obtain the cooling effect in machine assembly and which undergoes the magnetic action, and forms a magnetic loop with each division core  21 , thereby intending magnetic stabilization of the division cores  21 . In addition, the first and second bracket covers  30   a  and  40   a  and the annular ring bodies (first and second magnetic members)  30   b  and  40   b  are formed separately, respectively, but may be formed from integral members made of a magnetic material. Alternately, depending on to the magnetic action, one of the first and second bracket covers  30   a  and  40   a  may be provided with a magnetic body or an annular ring body made of or a magnetic material. 
     [Magnetic Action of the First and Second Brackets] 
     By thus forming each of the first bracket  30  and second bracket  40  using the magnetic material, in the case of three-phase driving, as shown in  FIG. 7A , the current is supplied to winding coils  23  of two adjacent division cores  21 , each division core  21  is excited, and as a result, the rotor  10  is pulled by excited magnetic poles and rotates in the arrow direction. In a state as shown in the figure, for example, the S pole is excited in the face facing the rotor  10  of the division core  21   l , the N pole is excited in the external wall face thereof, while the N pole is excited in the face facing the rotor  10  of the adjacent division core  21   a  and the S pole is excited in the external wall face thereof, and a first magnetic loop G 1  is formed. At the same time, as shown in  FIG. 7B , a magnetic flux coming out of the division core  21   l  enters the division core  21   a  through the annular ring body  30   b  that is the magnetic material of the first bracket  30 , the magnetic flux coming out of the division core  21   a  returns to the division core  21   l  through the rotor  10 , and a second magnetic loop G 2  is thus formed. Similarly, a magnetic flux coming out of the division core  21   l  enters the division core  21   a  through the annular ring body  40   b  that is the magnetic material of the second bracket  40 , the magnetic flux coming out of the division core  21   a  returns to the division core  21   l  through the rotor  10 , and a third magnetic loop G 3  is thus formed. As described above, as compared with the case of generally forming the magnetic loop only using the magnetic loop G 1 , in this configuration, the magnetic loop G 2  and third magnetic loop G 3  are formed, the magnetic path increases, and as a result, a magnetic flux leaking outside the machine remarkably decreases. Accordingly, it is possible to resolve magnetic instability and rotate the rotor  10  smoothly. 
     [Performance and Characteristics by the Magnetic Brackets] 
     Actually, as indicated in the characteristic graph shown in  FIG. 8 , as compared with the case where the first and second brackets  30  and  40  are made of a nonmagnetic material, a change in current passed through the division core  21  is of an almost linear characteristic, and a linear area width of rotation torque is also wider. 
     [Embodiment 1 of the Second Bracket] 
     Further, with respect to the second bracket  40 , the second contact surfaces  43  are formed in the second bracket  40  as shown in  FIG. 5A  as described below. The second contact surface  43  is formed in the shape of a ring in an inclined surface in line-contact with the other end face Srb of the division core  21 . In other words, the edge of the other end face Srb of the division core  21  comes into contact, in an acute angle, with the inclined surface in the shape of a circular truncated cone formed in the bracket. Concurrently therewith, in contrast to the division cores  21  formed of electromagnetic steel plates (silicon steels, etc.) as described previously, the second contact surfaces  43  are made of a soft metal material or resin material (aluminum alloy in the figure). Thus, the second contact surfaces  43  formed in the second bracket  40  are made of a material which undergoes the fastening force of fastening members  50  described later, and thereby deforms to be crushed to the edge portion of the division core  21 . 
     As described above, the second contact surface  43  is formed in the shape of a ring in the inclined surface, and is radially arranged such that the inclined surface shown in the figure has the shape of a positive circular truncated cone as shown in  FIG. 5A , and that the vertex O coincides with the shaft center x-x of the rotary shaft  11  supported by the bearing  41 . The reason is to prevent magnetic teeth from been biased when a plurality of division cores  21   a  to  21   l  are pressed by the contact surfaces  43  of the second bracket  40  as described later, by arranging the division cores equidistantly around the shaft center x-x of the rotary shaft as the center. 
     [Embodiment 2 of the Second Bracket] 
     Further, the second contact surfaces  43  are formed in the second bracket  40  as shown in  FIG. 6  as described below. The second contact surface  43  is formed of a spacer member  45  attached to the second bracket (metal material)  40 , and the spacer member  45  comes into surface-contact with the other end face Srb of the division core  21 . Then, the spacer member  45  is made of a resin material provided with magnetic characteristics which is obtained by adding a magnetic material and which deforms with ease by the fastening force of the fastening members  50  acted on the other end face Srb of the division core  21 . Accordingly, by forming the magnetic loop by the magnetic characteristics, it is possible to resolve magnetic instability due to the division cores  21 , and even when dimensional fluctuations occur in a plurality of division cores  21   a  to  21   l  annularly arranged, due to the characteristics of being de formable with ease, the contact surface deforms to follow the core end face, and does not cause a gap therebetween. 
     As described above, the first and second brackets  30  and  40  for merging the rotor  10  and stator  20  are integrated by the fastening members (coupling belts)  50 , and the distance L is determined by the thickness dimension of the division core  21 . Then, a cylindrical yoke not shown is used to wrap, and the housing of the rotating electrical machine is thus formed. 
     The action of the invention is described next. As shown in  FIG. 1A , the rotor  10  is comprised of the rotary shaft  11  and magnets  13  as described previously, and magnetic poles of the N poles and S poles are alternately arranged around the periphery of the rotor core  12 . In the rotor  10 , the rotary shaft  11  is supported rotatably by the bearings  31  and  41  of the first and second brackets  30  and  40  integrated by the fastening members  50 . By this means, the rotor  10  is supported to rotate the magnetic poles formed from the magnets  13  of the rotor  10  in a predetermined circular locus. Concurrently therewith, the shaft-direction (thrust-direction) position of the rotor  10  is positioned and supported by the E-ring  11   e  in the steps  32  and  42  of the rotary shaft  11 . 
     The above-mentioned stator  20  is comprised of a plurality of division cores  21   a  to  21   l  as shown in  FIG. 2 , and the division cores  21   a  to  21   l  are annularly coupled by fitting and coupling the concave portions  21   y  and convex portions  21   z  formed in the core pieces  21   x . Then, as shown in  FIGS. 4B and 5A , the division cores  21   a  to  21   l  are annularly arranged in their one end faces Sa with reference to the first contact surfaces  33  of the (annular ring body (first magnetic member)  30   b ) first bracket  30 . At this point, in the chained division cores  21 , the angle reference planes  21   u  are matched with the positioning protrusions  34  of the first bracket  30 . By this means, it is possible to position and arrange a plurality of division cores  21   a  to  21   l  so that the end faces Sra are aligned on the same plane, and concurrently, it is possible to locate angle positions of a plurality of annularly chained division cores  21  in predetermined positions. 
     Further, as shown in  FIG. 5A , the other end faces Srb of the above-mentioned division cores  21  are pressed and supported by the second contact surfaces  43  of the second bracket  40 . At this point, since the second contact surface  43  is formed of the inclined surface (Embodiment 1) or the spacer member (Embodiment 2), and is made of the material softer than the electromagnetic steel plates forming the division cores  21 , even when fluctuations occur in the thickness dimension among a plurality of division cores  21   a  to  21   l , the second contact surface  43  deforms, and neither a gap nor rattle arises between the surface  43  and the other end face Srb of the division core  21 . 
     Furthermore, the second contact surface  43  is formed of the inclined surface, and the inclined surface is in the shape of a positive cone where the vertex O coincides with the shaft center x-x of the rotary shaft  11 . By this means, it is possible to arrange a plurality of division cores  21   a  to  21   l  radially around the shaft center x-x of the rotary shaft  11  as the center. This arrangement is automatically aligned by fastening a pair of the first and second brackets  30  and  40  using the fastening members  50 . 
     The present invention relates to a stator structure of electromagnetic motors, generators, etc. and rotating electrical machines using the stator structure, and to improvements in a fixing structure of a stator provided with coils, and has industrial applicability. 
     In addition, this application claims priority from Japanese Patent Applications No. 2009-070694 and No. 2009-270901 incorporated herein by reference.