Abstract:
In a rotating electrical machine for vehicle, at least one of a rectifier device, a voltage regulator, and a brush holder includes an external terminal connection portion provided with an insert terminal inserted into resin and an insert nut inserted into the resin and superimposed on the insert terminal. The insert terminal includes a contact portion on a surface on a side opposing the insert nut and the insert terminal and the insert nut are superimposed via the contact portion and inserted into the resin. It thus becomes possible to provide a rotating electrical machine for vehicle provided with constituent components that are free from an inconvenience caused by a variance over time.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a rotating electrical machine for vehicle, such as an AC generator for vehicle mounted on a vehicle or the like, and more particularly, to a structure of constituent components thereof. 
         [0003]    2. Background Art 
         [0004]    Insert nuts to bury metal nuts in screw attachment portions are used for resin molded articles forming automobile components. As a configuration example of a component using the insert nut in the related art, for example, Patent Document 1 discloses a configuration in which a nut is placed on a bottom surface side of an exposed portion of an external connection electrode plate and the nut together with the external connection electrode plate is buried into a resin (for example, PPS) case by transfer molding. 
         [0005]    The resin molded articles in the related art are manufactured as is disclosed, for example, in Patent Document 1. That is, a cylindrical pin having a diameter slightly smaller than a diameter of a screw hole of a nut is provided to a tip end of a convex portion of a lower die and the nut to be inserted is placed so as to encircle the pin. A length of the pin is set to a length long enough to slightly protrude from an end face of the nut in a state where the nut encircles the pin. The convex portion of the lower die serves as a portion on which to mount the nut. The convex portion has a cylindrical base portion having a diameter larger than the diameter of the screw hole of the nut and smaller than an outside diameter of the nut. Then, by closing an upper die and the lower die, the nut is fixed as it is sandwiched between the cylindrical base portion and the external connection electrode plate. In this state, molten resin is poured into the dies and resin encapsulation is completed. A resin molded article provided with an insert nut is thus manufactured. 
         [0006]    The resin molded article manufactured as above eliminates a need to fix a nut using a tool when a bolt is fastened because the nut is inserted into the resin and therefore makes it easier to fasten a bolt. 
       CITATION LIST 
     Patent Document 
       [0000]    
       
         Patent Document 1: Japanese Patent No. 4540884 
       
     
         [0008]    During the manufacturing of the resin molded article in the related art disclosed in Patent Document 1, because the nut is sandwiched between the base portion of the lower die and the external connection electrode plate, mold resin is thought to be prevented from coming to an inner side of the nut. However, the nut is a part having a screw portion on the inner side and it is normal that a surface of the nut orthogonal to a direction of a shaft center of the nut is formed without aiming at a high degree of dimensional accuracy. Hence, even when the nut is sandwiched firmly between the base portion of the lower die and the external connection electrode plate, in a case where molten resin is poured into the dies at a high pressure by merely superimposing the surface of the nut that is relatively rough at a not-so-high degree of dimensional accuracy on the external connection electrode plate, because the nut and the external connection electrode plate are not fixed firmly by fixing means, such as caulking, not a little amount of resin may possibly come into a superimposed surface of the surface of the nut and the external connection electrode plate due to a high resin pressure during integral molding. 
         [0009]    As is known, the rotating electrical machine, such as an AC generator mounted on a vehicle, is provided with a rectifying device that converts an AC to a DC. The rotating electrical machine for vehicle is used in various severe environments and exposed to high temperature, high humidity, dry air and the like over a long period and resin used for the constituent components deteriorates with time. Hence, with the rotating electrical machine for vehicle in the related art provided with constituent components using resin molded articles formed as above, because unwanted resin is present in the superimposed portion of the insert nut and the external connection electrode plate, a dimension of the superimposed portion of the insert nut and the external connection electrode plate varies with deterioration of the resin. Consequently, the nut is loosened and the loosened nut causes an inconvenience that an electrical connection of the external connection electrode plate cannot be secured. Further, in the case of the resin molded articles in the related art as above, the nut is loosened by vibrations of the AC generator for vehicle. Then, the components can no longer maintain an assembled state and a failure may possibly occur in the rotating generator for vehicle. 
       SUMMARY OF THE INVENTION 
       [0010]    The invention is devised to solve the problems discussed above in the rotating electrical machine for vehicle in the related art and has an object to provide a rotating electrical machine for vehicle provided with constituent components that are free from an inconvenience caused by a variance over time. 
         [0011]    A rotating electrical machine for vehicle according to an aspect of the invention includes: a stator provided with a stator winding; a rotor provided with a field winding that generates a flux interlinked with the stator winding and inducing an AC electromotive force in the stator winding when driven to rotate; a rectifier device converting the AC electromotive force to DC power; a voltage regulator regulating magnitude of the induced AC power; and a brush holder holding a brush that supplies a rotor winding of the rotor with a current. At least one of the rectifier device, the voltage regulator, and the brush holder includes an external terminal connection portion provided with an insert terminal inserted into resin and an insert nut inserted into the resin and superimposed on the insert terminal. The insert terminal includes a contact portion on a surface on a side opposing the insert nut and the insert terminal and the insert nut are superimposed via the contact portion and inserted into the resin. 
         [0012]    In the rotating electrical machine for vehicle configured as above, at least one of the rectifier device, the voltage regulator, and the brush holder includes the external terminal connection portion provided with the insert terminal inserted into resin and the insert nut inserted into the resin and superimposed on the insert terminal. Also, the insert terminal includes the contact portion on the surface on a side opposing the insert nut and the insert terminal and the insert nut are superimposed via the contact portion and inserted into the resin. Hence, it becomes possible to maintain a contact state of the insert terminal and the insert nut even when the resin deteriorates. Accordingly, because a superimposed dimension of the insert terminal and the insert nut does not vary, there occurs no inconvenience, such as the insert nut becomes loose. 
         [0013]    The foregoing and other objects features, aspects, and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a sectional side view of a rotating electrical machine for vehicle according to a first embodiment of the invention; 
           [0015]      FIG. 2  is a plan view of the rotating electrical machine for vehicle according to the first embodiment of the invention showing one end in an axial direction in a state where a rear cover is removed; 
           [0016]      FIG. 3  is a plan view showing a circuit board of a rectifier device in the rotating electrical machine for vehicle according to the first embodiment of the invention; 
           [0017]      FIG. 4A  and  FIG. 4B  are cross sections used to describe an external terminal connection portion of the circuit board in the rotating electrical machine for vehicle according to the first embodiment of the invention; 
           [0018]      FIG. 5A ,  FIG. 5B , and  FIG. 5C  are views showing a disassembled state and used to describe the external terminal connection portion of the circuit board in the rotating electrical machine for vehicle according to the first embodiment of the invention; 
           [0019]      FIG. 6A ,  FIG. 6B , and  FIG. 6C  are views showing a disassembled state and used to describe an external terminal connection portion of a circuit board in a rotating electrical machine for vehicle according to a second embodiment of the invention; 
           [0020]      FIG. 7  is a plan view of a voltage regulator applicable to the rotating electrical machine of the invention; and 
           [0021]      FIG. 8  is a plan view of a brush holder applicable to the rotating electrical machine of the invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     First Embodiment 
       [0022]    Hereinafter, a rotating electrical machine for vehicle according to a first embodiment of the invention will be described. The rotating electrical machine for vehicle according to the first embodiment of the invention described below is formed as a three-phase AC generator for vehicle.  FIG. 1  is a sectional side view of the rotating electrical machine for vehicle according to the first embodiment of the invention.  FIG. 2  is a plan view of the rotating electrical machine for vehicle according to the first embodiment of the invention showing one end in an axial direction in a state where a rear cover is removed. 
         [0023]    Referring to  FIG. 1  and  FIG. 2 , an AC generator  1  for vehicle includes a casing  4  formed of a front bracket  2  and a rear bracket  3  each shaped like substantially a bowl and made of aluminum, a shaft  6  supported on the casing  4  in a rotatable manner via a pair of bearings  5 , a pulley  7  firmly fixed to the shaft  6  at one axial end protruding toward a front side of the casing  4 , a rotor  8  fixed to the shaft  6  and provided inside the casing  4 , a pair of fans  11  fixed to respective axial end faces of the rotor  8 , and a stator  12  fixed to the casing  4  so as to surround the rotor  8 . 
         [0024]    The rotating electrical machine for vehicle according to the first embodiment of the invention further includes a pair of slip rings  15  fixed to the shaft  6  in an extended portion extending toward a rear side of the casing  4  and supplying the rotor  8  with a current, a pair of brushes  16  in sliding contact with surfaces of the respective slip rings  15 , a brush holder  17  in which to house these brushes  16 , a voltage regulator  19  attached to a heat sink  18  provided on an outer diameter side of the rear bracket  3  with respect to the brush holder  17  and regulating magnitude of an AC voltage generated in a stator winding  14  provided to the stator  12  and described below, a connector  20  molded integrally with an attachment portion of the heat sink  18  and outputting a signal from the voltage regulator  19  to an outside device (not shown), such as a battery, and inputting a signal from the latter into the former, a rectifier device  21  provided on a rear side of the rear bracket  3  and converting an AC electromotive force generated in the stator  12  to a DC output voltage, and a protection cover  25  attached to the rear bracket  3  so as to cover the brush holder  17 , the voltage regulator  19 , and the rectifier device  21 . 
         [0025]    The rotor  8  is a Lundell-type rotor and includes a field winding  9  that generates a flux when an excitation current is flown and a pole core  10  provided so as to cover the field winding  9  and forming a magnetic pole with the flux. The stator  12  includes a cylindrical stator iron core  13  and a stator winding  14  wound around the stator iron core  13  and inducing an AC electromotive force due to a variance of the flux from the field winding  9  in association with rotations of the rotor  8 . The stator winding  14  is formed of first and second three-phase stator windings that are two independent windings out of phase by 30 [deg]. The stator iron core  13  of the stator  12  provided so as to surround the rotor  8  is sandwiched between opening ends of the front bracket  2  and the rear bracket  3  and fastened by a plurality of bolts from both axial ends via the front bracket  2  and the rear bracket  3 . The stator iron core  13  is therefore pinched by the front bracket  2  and the rear bracket  3 . 
         [0026]    The rectifier device  21  includes, as will be described below, a substantially C-shaped positive-electrode-side heat sink  22  on which are mounted six positive-electrode-side rectifier elements  22   a , a substantially C-shaped negative-electrode-side heat sink  23  on which are mounted six negative-electrode-side rectifier elements  23   a , and a substantially C-shaped circuit board  24 . The positive-electrode-side heat sink  22  and the negative-electrode-side heat sink  23  are placed one on top of the other with the circuit board  24  in between and, as is shown in  FIG. 2 , provided on the periphery of the shaft  6  so that both open ends of the C shape are positioned on the upper side of  FIG. 2  and fixed to the rear bracket  3 . 
         [0027]    The positive-electrode-side rectifier elements  22   a  are disposed on the positive-electrode-side heat sink  22  shown in  FIG. 2 . The negative-electrode-side rectifier elements  23   a  are disposed on the negative-electrode-side heat sink  23  shown in  FIG. 2 . The positive-electrode-side rectifier elements  22   a  and the negative-electrode-side rectifier elements  23   a  are connected so as to form two three-phase bridge circuits via the circuit board  24 . AC-side terminal of the three-phase bridge circuits are connected to leads line of the three-phase stator windings. 
         [0028]    Positive-electrode-side DC terminals of the two three-phase bridge circuits are connected commonly via the positive-electrode-side heat sink  22  and connected to a positive-electrode-side terminal of an in-vehicle battery (not shown). 
         [0029]    The rectifier device  21  configured as above is disposed about the shaft  6  on a plane orthogonal to the shaft center of the shaft  6  on an outer circumferential side of the slip rings  15 . The positive-electrode-side heat sink  22 , the circuit board  24 , and the negative-electrode-side heat sink  23  forming the rectifier device  21  are placed one on top of another to form a single piece that is fixedly fastened to an outer end face of the rear bracket  3  with three screws  40 . The lead line  14   a  of the three-phase stator winding forming the stator winding  14  is pulled out from the rear bracket  3  and connected to six winding lead line connection terminals  240  described below and provided to the circuit board  24  in an outer peripheral portion. 
         [0030]    The lead lines of the three-phase stator windings are connected to the three-phase bridge circuits at respective predetermined positions via a conductor inserted into the circuit board  24 . 
         [0031]    The brush holder  17  is disposed between open tip ends of the substantially C-shaped rectifier device  21  and fixedly fastened to the outer end face of the rear bracket  3  with screws  41 . A pair of brush connection conductors  17   a  and  17   b  provided to the brush holder  17  is electrically connected to a pair of the brushes  16 . The voltage regulator  19  is disposed between open tip ends of the substantially C-shaped rectifier device  21  on the outer diameter side of the rear bracket  3  with respect to the brush holder  17  and fixedly fastened to the outer end face of the rear bracket  3  with two screws  42 . A positive-electrode-side terminal of the voltage regulator  19  is connected to an external terminal connection portion  244  of the circuit board  24  as will be described below. 
         [0032]    The circuit board  24  will now be described.  FIG. 3  is a plan view showing the circuit board of the rectifier device in the rotating electric machine for vehicle according to the first embodiment of the invention. As is shown in  FIG. 3 , the circuit board  24  is shaped like substantially a capital C as with the positive-electrode-side heat sink  22  and the negative-electrode-side heat sink  23 , and as has been described above, interposed between the positive-electrode-side heat sink  22  and the negative-electrode-side heat sink  23 . The circuit board  24  includes the external terminal connection portion  244  having an insert terminal  26  inserted into an insulating board  241  molded from resin and an insert nut  27  inserted into the insulating board  241 . 
         [0033]    Also, the circuit board  24  includes the six winding lead line connection terminals  240  provided to the outer peripheral portion, six positive-electrode-side rectifier element connection terminals  245  connected to the respective six positive-electrode-side rectifier elements  22   a  described above, six negative-electrode-side rectifier element connection terminals  246  connected to the respective six negative-electrode rectifier elements  23   a  described above, and three screw through-holes  247  to let the respective three screws  40  pass through. 
         [0034]    The external terminal connection portion  244  of the circuit board  24  will now be described.  FIGS. 4A and 4B  are cross sections used to describe the external terminal connection portion of the circuit board in the rotating electric machine for vehicle according to the first embodiment of the invention.  FIG. 4A  is a cross section used to describe the external terminal connection portion of the circuit board and  FIG. 4B  is a cross section used to describe a state where an external electrode is connected to the external terminal connection portion of the circuit board. As is shown in  FIG. 4A , the external terminal connection portion  244  of the circuit board  24  includes the insert terminal  26  inserted into the insulating board  241  and the insert nut  27  inserted into the insulating board  241  below the insert terminal  26 . 
         [0035]    As is shown in  FIG. 4B , a positive-electrode-side terminal  191  of the voltage regulator  19  is superimposed on the insert terminal  26  in the external terminal connection portion  244  of the circuit board  24  and electrically and mechanically connected to the insert terminal  26  by a screw  43  threaded into the insert nut  27 . 
         [0036]      FIGS. 5A through 5C  are views showing a disassembled state and used to describe the external terminal connection portion of the circuit board in the rotating electrical machine for vehicle according to the first embodiment of the invention.  FIG. 5A  is a plan view of the insert terminal.  FIG. 5B  is a cross section of the insert terminal taken on the line A-A of  FIG. 5A .  FIG. 5C  is a cross section of the insert nut. As are shown in  FIGS. 5A and 5B , the insert terminal  26  is provided with a through-hole  26   c  to let the screw  43  pass through and three spherical contact portions  26   a  formed apart from one another on the periphery of the through-hole  26   c.    
         [0037]    The contact portions  26   a  are formed, for example, by pressing work so as to protrude from the surface of the insert terminal  26  on the side opposing the surface of the insert nut  27 . In a case where the contact portions  26   a  are provided to the insert terminal  26  by pressing work, concave portions  26   b  as a result of punching out the contact portions  26   a  by pressing are formed in the insert terminal  26 . The contact portions  26   a  of a protruding shape can be formed by press molding at the same time as a step of punching out the insert terminal  26  from a plate-like conductor. Hence, the contact portions  26   a  can be formed without any extra cost. 
         [0038]    It should be appreciated that the contact portions  26   a  are not limited to the configuration shown in  FIGS. 5A  through  5 C. Contact portions of a protruding shape alone may be provided by omitting the concave portions  26   b . Alternatively, other configurations, such as a convex shape other than a spherical shape and a toroidal shape, may be selected suitably. Also, it goes without saying that the number and locations of the contact portions  26   a  are not limited to those specified above. 
         [0039]    By integrally molding the contact portions  26   a  provided to the insert terminal  26  with resin when the circuit board  24  is molded from resin by sandwiching the superimposed insert terminal  26  and insert nut  27  between unillustrated upper and lower molding dies and by actively pressing the contact portions  26   a  provided to the insert terminal  26  against the surface of the insert nut  27 , the contact portions  26   a  ensure contact between the insert terminal  26  and the insert nut  27  and determine a final superimposed dimension of the insert terminal  26  and the insert nut  27 . 
         [0040]    As has been described, the positive-electrode-side terminal  191  of the voltage regulator  19  is, as is shown in  FIG. 4B , placed on the insert terminal  26  exposed in the external terminal connection portion  244  of the circuit board and integrally connected to the insert terminal  26  electrically and mechanically with the screw  43  threaded into the insert nut  27 . 
       Second Embodiment 
       [0041]      FIGS. 6A through 6C  are views showing a disassembled state and used to describe an external terminal connection portion of a circuit board in a rotating electrical machine for vehicle according to a second embodiment of the invention.  FIG. 6A  is a plan view of an insert terminal.  FIG. 6B  is a cross section of the insert terminal taken on the line A-A of  FIG. 6A .  FIG. 6C  is a cross section of an insert nut. The second embodiment shown in  FIGS. 6A through 6C  is configured in such a manner that the insert terminal  26  is provided with a contact portion  26   d  formed along a peripheral rim portion of the through-hole  26   c  to let the screw  43  pass through. The contact portion  26   d  is formed of a burr provided as a result of punching out the through-hole  26   c  in the insert terminal  26 . Hence, there is no need for an extra step of forming the contact portion  26   d.    
         [0042]    Although the contact portion  26   d  shown in  FIG. 6B  is enlarged, it is only necessary for the contact portion  26   d  to protrude like a burr and the contact portion  26   d  is not necessarily shaped like a ring. As has been described above, by integrally molding the contact portion  26   d  with resin during the resin molding by sandwiching the superimposed insert terminal  26  and insert nut  27  between the upper and lower molding dies and by actively pressing the contact portion  26   d  against the surface of the insert nut  27 , the contact portion  26   d  ensures contact between the insert terminal  26  and the insert nut  27  and determines a final superimposed dimension of the insert terminal  26  and the insert nut  27 . 
         [0043]    The first and second embodiments of the invention above have described the rotating electrical machine for vehicle particularly in a case where the rotating electrical machine for vehicle is applied to the external terminal connection portion of the rectifier device. However, it goes without saying that the rotating electrical machine for vehicle of the invention can be also applied to external terminal connection portions  191  and  192  of the voltage regulator  19  as a constituent component of an AC generator for vehicle shown in  FIG. 7  and to an external terminal connection portion  171  of the brush holder  17  as a constituent component of an AC generator for vehicle shown in  FIG. 8 . 
         [0044]    Various modifications and alterations of this invention will be apparent to those skilled in the art without departing from the scope and spirit of this invention, and it should be understood that this is not limited to the illustrative embodiments set forth herein.