JP4710800B2 - AC generator for vehicles - Google Patents

Description

  The present invention relates to a vehicle AC generator mounted on a passenger car, a truck, or the like.

Conventionally, it has been known that cooling air that has passed through the rear cover of a vehicular AC generator cools the rectifying element by cooling the embossed portion provided on the radiating fin of the rectifying device and then passing through the through-holes around the embossing. (For example, refer to Patent Document 1). With such a structure, the rectifying element is directly cooled by the cooling air passing through the through hole. In addition, a structure is also known in which a large number of rectifying elements are arranged to expand the radiating fins in a horseshoe shape in order to improve the cooling performance (for example, see Patent Document 2).
JP-A-10-56760 (page 3-5, FIG. 1-9) JP 2004-147486 A (page 6-14, FIG. 1-15)

  By the way, in the structure disclosed by patent document 1, since the cooling air which passed the embossed part of the radiation fin is divided into the component which passes the through-hole around an embossed part, and the component which flows through the surface of a radiation fin, it passed the rear cover. There was a problem that the cooling air could not be efficiently guided to the periphery of the rectifying element and the cooling performance was lowered. Further, Patent Document 1 discloses a structure in which a part of the radiating fin is bent or a partition is added. However, a part of the cooling air is passed through the through hole and the rest is passed through the surface of the radiating fin. It is the same, and the rectifying element cannot be efficiently cooled. On the other hand, it is necessary to further reduce the temperature of the rectifier against the temperature rise associated with the increase in the output of the vehicle alternator corresponding to the increase in the electric load for vehicles in recent years, and the cooling air is efficiently used. A method is desired.

  In addition, as disclosed in Patent Document 2, the heat radiation fin expanded in a horseshoe shape for improving the cooling performance is difficult to secure the plane accuracy, and the connection of the rectifying device in a state where the plane accuracy of the heat radiation fin is not ensured. If the terminal portion and the lead wires of the stator and the lead wires of the rectifier elements are connected to form a rectifier circuit, an excessive load may be applied to the leads of the rectifier elements. As a result, the life of the rectifying element may be reduced.

  Moreover, in order to improve the reliability of the electrical connection between the rectifying element and the radiating fin, there is a structure in which the rectifying element is mechanically press-fitted into the radiating fin as shown in Patent Document 2. At this time, in order to stabilize the press-fitting joint, in order to secure a predetermined press-fitting margin, it is common to perform a punching process for press-fitting the rectifying element on the heat radiation fin. If the area of the heat dissipating fins is increased in a horseshoe shape to improve cooling, the rigidity decreases. Therefore, if the above-described drilling process is performed, the dimensional accuracy of the hole may not be ensured due to vibration during the process. As a result, a local mechanical stress is generated in the press-fitted rectifying element, and a problem that the life of the rectifying element is reduced may be considered.

  Furthermore, there is a possibility that a failure may occur due to an impact directly applied to the rectifying element due to dropping or the like during an intermediate process until the rectifying device is assembled or during conveyance.

  The present invention was created in view of the above points, and its purpose is to improve the cooling performance of the rectifier and to reduce the mechanical stress on the rectifier and to improve the reliability of the rectifier. Another object of the present invention is to provide an automotive alternator that can be made to operate.

  In order to solve the above-described problems, an AC generator for a vehicle according to the present invention includes a cooling fan that rotates in conjunction with a rotor, a stator having a stator winding, and an alternating current generated by the stator winding. A rectifier that rectifies electromotive force into direct current and a rear cover that covers the rectifier are provided. The rectifier includes a plurality of rectifier elements, a heat radiation fin to which the plurality of rectifier elements are attached, and a heat radiation fin. A plurality of rectifying elements and a sub fin projecting toward the rear cover so as to surround each of the plurality of rectifying elements, and the heat radiating fin is formed with a through hole leading from the internal space partitioned by the sub fin to the back side of the radiating fin, The rear cover is formed with a cooling air suction hole at a position corresponding to the sub fin. As a result, the cooling air sucked from the suction hole of the rear cover can be guided to the vicinity of the rectifying element through the internal space of the sub fin, so that the rectifying element can be efficiently cooled and the cooling performance of the rectifying device is improved. Is possible. Further, by providing the sub fin so as to surround the periphery of the rectifying element, the strength around the mounting hole of the rectifying element can be increased, so that the roundness of the mounting hole can be improved, and the locality with respect to the rectifying element can be improved. Generation of mechanical stress can be suppressed. Furthermore, it is possible to prevent the flat portion of the rectifying element from being directly subjected to an impact during the intermediate process until the rectifying device is assembled or during conveyance. As described above, the mechanical stress on the rectifying element can be reduced and the reliability of the rectifying element can be improved.

Further, the rectifying element described above has a circular flat surface portion exposed to the internal space defined by the sub fins, and the sub fin has a cylindrical shape in which the flat surface portion is arranged at the center of the bottom surface . Thereby, the rear cover side of the rectifying element can be cooled substantially uniformly.

  In addition, it is desirable that the above-described sub fin is formed with a protruding portion that protrudes toward the internal space. Thereby, the heat dissipation of a subfin can be improved and the cooling property of a rectifier can further be improved.

  Further, it is desirable that the suction hole formed at a position corresponding to the sub fin described above has a shape that is the same as or smaller than the inner peripheral shape of the end portion of the sub fin on the rear cover side. Thereby, all the cooling air taken in from the suction hole corresponding to the sub fin can be efficiently guided to the internal space of the sub fin.

  Hereinafter, an AC generator for a vehicle according to an embodiment to which the present invention is applied will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of an AC generator for a vehicle according to an embodiment. As shown in FIG. 1, the vehicle alternator 1 according to this embodiment includes a rotor 2 that is driven to rotate from an engine via a belt (not shown) and a pulley 10, and a stator winding 41. A rectifier 5 that rectifies an alternating electromotive force generated by the stator 4, the front frame 3a and the rear frame 3b that support the rotor 2 and the stator 4 via a pair of bearings, and the stator winding 41 into a direct current. And a brush device 7 that holds a brush that supplies a field current to the field coil 22 of the rotor 2, a regulator 8 that controls the output voltage, and the rectifier 5, the brush device 7, the regulator 8, and the like. A rear cover 9 attached to the end face of the rear frame 3b is included. The rotor 2 includes a cooling fan 26 as a cooling air generator that sucks cooling air from the outside through the rear cover 9 on the end face in the axial direction of the rotor magnetic pole 24. The cooling fan 26 rotates in conjunction with the rotor 2.

  Next, details of the rectifier 5 will be described. FIG. 2 is a front view of the rectifier 5. The rectifying device 5 of the present embodiment includes a positive-side radiating fin 57 and a negative-side radiating fin 58 that are spaced apart from each other in the axial direction across the terminal block 51. Six positive side rectifying elements 53 are press-fitted and fixed to attachment holes which are through holes with the positive side heat radiating fins 57 facing the frame side, and the respective connection terminals 52 projecting from the terminal block 51. Are joined by TIG welding. In addition, six negative rectifying elements 55 are press-fitted and fixed to attachment holes, which are through holes, with the lead 55 a facing the rear side, and the respective leads 55 a protrude from the terminal block 51. The connection terminal 52 is joined by TIG welding.

  The positive-side radiating fin 57 described above has six cylindrical sub-fins 500 corresponding to each of the six positive-side rectifying elements 53. FIG. 3 is an enlarged plan view of one cylindrical sub fin 500. FIG. 4 is a cross-sectional view taken along line O-IV in FIG. FIG. 4 also shows the positional relationship between the cylindrical sub-fin 500 and the rear cover 9. FIG. 5 is a cross-sectional view taken along the line OV of FIG. FIG. 6 is a perspective view of the cylindrical sub fin 500.

  The cylindrical sub fin 500 is formed integrally with the positive-side radiating fin 57 and protrudes toward the rear cover 9 so as to surround a mounting hole 520 provided for press-fitting the positive-side rectifying element 53. On the inner peripheral side of the cylindrical sub-fin 500 (internal space defined by the cylindrical sub-fin 500), the flat portion 53a on the opposite lead side of the positive-side rectifying element 53 is exposed. 53a has a cylindrical shape arranged at the center of the bottom surface. In addition, the cylindrical sub-fin 500 is connected to each surface smoothly at the boundary by enlarging the outer diameter in the vicinity of the surface of the positive-side radiating fin 57 provided with the mounting hole 520. In this boundary portion, a plurality of through holes 502 penetrating in the plate thickness direction of the positive electrode side radiating fins 57 and in the radial direction of the cylindrical sub fins 500 are provided. The through-holes 502 are formed at, for example, four positions at intervals of 90 °, and a part of the cooling air flowing from the rear cover 9 side to the surface of the positive-side radiating fin 57 along the outer periphery of the cylindrical sub-fin 500 is radiated on the positive-side. It is used to guide the fin 57 to the back side or to guide the cooling air introduced to the inner peripheral side of the cylindrical sub-fin 500 to the outer peripheral side and the back side of the positive-side radiating fin 57.

  As shown in FIG. 4, the rear cover 9 is assembled with a predetermined gap between the rear cover 9 and the tip of the cylindrical sub-fin 500. The rear cover 9 is provided with a plurality of suction holes 91 for taking cooling air from the outside into the rectifier 5 side. At least a part of these suction holes 91 is provided at a position corresponding to the cylindrical sub fin 500 (a position facing an internal space defined by the cylindrical sub fin 500). Therefore, when the cooling air W is sucked into the inside of the rear cover 9 from the outside of the rear cover 9 through the suction hole 91 facing the inner region of the cylindrical sub-fin 500, the cooling air W is positively rectified along the inner peripheral wall of the cylindrical sub-fin 500. The positive electrode side rectifying element 53 is cooled by being guided to the flat portion 53 a of the element 53. When the cooling air W further passes through the through-hole 502, the cooling air W is cooled and guided to the back side.

  As described above, in the vehicle alternator 1 of the present embodiment, the cooling air sucked from the suction hole 91 of the rear cover 9 can be guided to the vicinity of the positive-side rectifying element 53 through the internal space of the cylindrical sub-fin 500. The positive-side rectifying element 53 can be efficiently cooled, and the cooling performance of the rectifying device 5 can be improved.

  The positive-side rectifying element 53 has a circular flat surface portion 53a exposed to the internal space defined by the cylindrical sub-fin 500, and the flat surface portion 53a is disposed at the center of the bottom surface. Therefore, the rear cover 9 side of the positive-side rectifying element 53 can be cooled substantially uniformly.

  FIG. 7 is an enlarged plan view of a modified cylindrical sub-fin. 8 is a cross-sectional view taken along line O-VIII in FIG. 9 is a cross-sectional view taken along line O-IX in FIG. FIG. 10 is a perspective view of a modified cylindrical sub-fin. The cylindrical sub fin 500A of the modification shown in these figures is divided into four divided wall portions 510 by extending the through hole 502 as it is with respect to the cylindrical sub fin 500 shown in FIG. And the direction parallel to the central axis of the cylindrical wall (on the surface of the positive-side radiating fin 57 on the inner peripheral side of the dividing wall portion 510 (inside the inner space defined by the cylindrical sub-fins 500A)) The difference is that convex portions 512 are provided in a direction perpendicular to the above. In the example shown in FIG. 7 and the like, the convex portions 512 are formed only on the three divided wall portions 510, but the convex portions 512 are provided on all the divided wall portions 510, or a plurality of convex portions are provided on each divided wall portion 510. A portion 512 or a recess may be provided.

  Cooling air W is sucked from the outside of the rear cover 9 through the suction hole 91 facing the inner region of the cylindrical wall, even if the cylindrical wall is not completely cylindrical like the cylindrical sub fin 500A of this modification. When this is done, the cooling air W can be guided substantially along the cylindrical wall to the flat portion 53a of the positive-side rectifying element 53, and the rectifying element 53 can be efficiently cooled. Moreover, the surface area of the inner peripheral side of each division wall part 510 can be expanded, and cooling property can further be improved. Moreover, since the convex part 512 which protrudes in the internal space side is formed in the cylindrical subfin 500A, the heat dissipation of the cylindrical subfin 500A can be enhanced, and the cooling performance of the rectifying device 5 can be further improved. .

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention. In the embodiment described above, the cylindrical sub fins 500 and 500 </ b> A are formed in a cylindrical shape. However, a part of the cooling air sucked into the rear cover 9 through the suction hole 91 is positively brought into the vicinity of the flat portion of the positive-side radiating fin 52. Since it only needs to be able to guide, the cylindrical shape may be formed into a polygonal shape (including the case where the wall portion is divided by the through hole as shown in FIG. 10). Also, a cylindrical wall extending from the rear cover 9 side toward the inner diameter side or outer diameter side of the cylindrical sub fins 500 and 500A is provided, and the cooling air sucked from the suction hole 91 of the rear cover 9 is surely positively rectified. You may make it guide | induce to the plane part 53a of the element 53. FIG.

  Further, as shown in FIG. 11, the shape of the suction hole 91 of the rear cover 9 is made to be the same as or smaller than the inner diameter of the cylindrical wall according to the shape of the cylindrical sub-fin 500 (500A may be used). The cooling air sucked through each suction hole 91 corresponding to each of the cylindrical sub-lins 500 may be guided to the flat portion 53 a of the positive-side rectifying element 53. By providing a suction hole 91 having a shape that is the same as or smaller than the inner peripheral shape of the end portion on the rear cover 9 side of the cylindrical sub fin 500 at a position corresponding to the cylindrical sub fin 500, the cylindrical sub fin 500 corresponds to the cylindrical sub fin 500. All of the cooling air taken from the suction hole 91 can be efficiently guided to the internal space of the cylindrical sub fin 500.

  In the embodiment described above, the positive-side radiation fins 57 of the rectifying device 5 are disposed on the side close to the rear cover 9. However, when the negative-side radiation fins 58 are disposed on the side close to the rear cover 9, this negative-side heat dissipation is performed. The cylindrical sub fins 500 and 500 </ b> A may be formed on the fin 58.

  In addition, since the cylindrical sub fin 500 can improve the rigidity of the positive electrode side radiation fin 57 expanded in a horseshoe shape for improving the cooling performance, there is an effect of improving the planar accuracy of the fin alone. Further, since the strength of the ring around the attachment hole 520 of the positive rectifying element 53 is improved, the roundness of the attachment hole 520 of the positive rectifying element 53 is improved, and local stress generation can be suppressed. Furthermore, it is possible to prevent the flat portion of the positive-side rectifying element 53 from being directly subjected to an impact during an intermediate process or assembling until the rectifying device 5 is assembled. As described above, the mechanical stress on the positive rectifier 53 can be reduced and the reliability of the positive rectifier 53 can be improved.

It is sectional drawing of the alternating current generator for vehicles of one Embodiment. It is a front view of a rectifier. It is an enlarged plan view of a cylindrical subfin. It is the O-IV sectional view taken on the line of FIG. It is the OV sectional view taken on the line of FIG. It is a perspective view of a cylindrical subfin. It is an enlarged plan view of the cylindrical subfin of a modification. It is the O-VIII sectional view taken on the line of FIG. It is the O-IX sectional view taken on the line of FIG. It is a perspective view of the cylindrical subfin of a modification. It is a figure which shows the modification of the surrounding structure of a cylindrical subfin.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle alternator 2 Rotor 3a Front frame 3b Rear frame 4 Stator 5 Rectifier 7 Brush device 8 Regulator 9 Rear cover 10 Pulley 26 Cooling fan 51 Terminal block 52 Connection terminal 53 Positive side rectifier 55 Negative side rectifier 57 Positive-side radiating fin 58 Negative-side radiating fin 91 Suction hole 500 Cylindrical sub-fin 502 Through-hole 510 Dividing wall portion 512 Protruding portion 520 Mounting hole

Claims (3)

A cooling fan that rotates in conjunction with the rotor, a stator having a stator winding, a rectifier that rectifies an alternating electromotive force generated in the stator winding into a direct current, and a rear cover that covers the rectifier; In a vehicle alternator comprising:
The rectifier includes a plurality of rectifier elements, a heat radiation fin to which the plurality of rectifier elements are attached, and a heat sink formed integrally with the heat radiation fin and projecting toward the rear cover so as to surround each of the plurality of rectifier elements. A sub-fin,
The heat radiating fin is formed with a through hole leading from the internal space defined by the sub fin to the back side of the heat radiating fin,
The rear cover is formed with a cooling air suction hole at a position corresponding to the sub fin .
The rectifying element has a circular flat portion exposed in an internal space defined by the sub fins,
The Sabufin The vehicle AC generator according to claim Rukoto to have a cylindrical shape wherein the flat portion is arranged in the center of the bottom surface. In claim 1,
The sub-fin is provided with a convex portion that protrudes toward the inner space. In claim 1 or 2,
The vehicle alternator according to claim 1, wherein the suction hole formed at a position corresponding to the sub fin has a shape that is the same as or smaller than an inner peripheral shape of an end portion of the sub fin on the rear cover side.

Images