JP5614398B2 - 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, a rectifying device is formed by attaching a rectifying element to a heat dissipating fin extending in a direction perpendicular to the rotating shaft, and the cooling fan attached to the rotor is rotated to be provided on the end surface in the axial direction of the rear cover. 2. Description of the Related Art A vehicular AC generator that cools a rectifier by taking cooling air from an intake window and directing it toward a heat radiation fin along the surface thereof is known (see, for example, Patent Documents 1 and 2). ).

JP 2005-509393 A JP-A-10-56762

  By the way, in the rectifier used in the conventional vehicle alternator, the cooling air taken in from the suction window provided on the axial end surface of the rear cover does not flow entirely along the entire surface of the cooling fin. Therefore, there was a problem that the cooling performance was poor. For example, in the vehicle alternator disclosed in Patent Document 2, the cooling air taken in from the innermost suction port among the plurality of suction windows provided on the end surface in the axial direction of the rear cover is supplied to the surface of the radiating fin. It does not flow along the entire surface, but flows along a part of the surface on the inner diameter side and is then sucked into the frame, so it cannot be said that it contributes sufficiently to cooling of the radiation fins. In addition, if the cooling performance of the rectifying device is poor, the temperature of the rectifying element provided in the rectifying device increases, leading to a reduction in the life of the rectifying device, or by increasing the area of the radiating fins to ensure cooling performance. The overall size of the machine will increase, and the use of a rectifying element with high heat resistance will cause inconveniences such as an increase in component costs.

  This invention is created in view of such a point, The objective is to provide the alternating current generator for vehicles which can improve the cooling property of a rectifier.

In order to solve the above-described problems, an automotive alternator according to the present invention includes a rotor that rotates together with a cooling fan, a stator that is disposed to face the rotor, and a frame that supports the rotor and the stator. In the vehicular AC generator including a rectifier having a radiating fin that is fixed to the frame and cools the rectifying element, and a rear cover that covers an electrical component including the rectifying device, the radiating fin is connected to the rotating shaft of the rotor. A first fin that extends in the radial direction, and a cooling air suction window is provided on a side surface of the rear cover on the outer side in the radial direction of the first fin and on the rear side of the first fin. The cooling fan suction window is not formed on the opposite end surface of the rear cover that corresponds to the heat dissipating fin and is formed from the suction window to the rear cover as the cooling fan rotates. Inside Captured cooling air flows from the radially outward radially inward along the first fin, flowing from further formed ventilated space radially inward of the first fin to the cooling fan side.

  Cooling air introduced from the outside in the radial direction of the rectifier can flow along the surface of the radiating fin, so the entire cooling air contributes to cooling of the radiating fin, improving the cooling performance of the rectifier Can be made. In addition, along with the improved cooling performance of the rectifier, it is possible to extend the life by reducing the temperature of the rectifier, reduce the size of the entire generator by reducing the area of the radiating fins, and reduce component costs by using a rectifier with low heat resistance .

Further, the rear cover described above, the opposing surface corresponding to the radiating fins a axial end face, since the intake window of the cooling air are not formed, it is possible to introduce cooling air only from the outside in the radial direction of the heat radiation fins In addition, the cooling performance of the rectifier can be reliably improved.

  Moreover, it is desirable that the above-described heat dissipating fins have second fins that are formed radially with respect to the rotation axis of the rotor and extend from the first fins to the rear side. Thereby, it becomes possible to enlarge the surface area of a radiation fin, and can further improve the cooling property of a rectifier. Further, when focusing on the two second fins adjacent to each other in the circumferential direction, the distance between them becomes narrower toward the inner side in the radial direction. Therefore, the speed of the cooling air increases toward the inner side in the radial direction, and the cooling efficiency is further increased. be able to.

  Moreover, as for the 2nd fin mentioned above, it is desirable for the rear side edge part along an axial direction to contact | abut to the rear cover. As a result, the cooling air flowing through the gap between the rectifying device and the rear cover can be eliminated and the entire cooling air can be passed through the radiation fins, and the cooling performance of the rectifying device can be further improved without increasing the amount of cooling air. .

  The rear cover described above is preferably formed of a metal material. As a result, heat is transferred from the radiating fins to the rear cover, and the rear cover can be used as a radiating member.

  Moreover, it is desirable that the above-described rear cover has a third fin that protrudes toward the heat radiating fin. Thereby, the heat dissipation effect at the time of utilizing a rear cover as a heat radiating member can further be improved.

  In addition, it is desirable that the above-described radiating fin and the rear cover are integrally molded. Thereby, the cost can be reduced by reducing the number of parts. In addition, the heat transfer from the radiating fin to the rear cover can be improved, and the cooling performance of the rectifier can be further improved.

  In addition, it is desirable to use the axial end face of the frame described above as the first fin. Thereby, the cost can be reduced by reducing the number of parts. In particular, by using a frame having a large heat capacity as a heat radiating fin, it is possible to alleviate the temperature change during the transition of the rectifying element and to reduce the peak temperature.

  The first fins described above are desirably arranged in a plurality of stages along the rotation axis of the rotor. As a result, the surface area of the radiating fin can be further increased, and the cooling performance of the rectifier can be further improved.

  In addition, the axial position of a region that is a part of the axial end surface of the rear cover and that is opposed to the ventilation space formed on the radially inner side of the first fin is inclined toward the cooling fan side as the radial inner side is reached. It is desirable to make it. Accordingly, the cooling air can be prevented from staying in the ventilation space formed on the radially inner side of the heat dissipating fin and the flow can be smoothed, and the cooling performance can be improved by increasing the air volume accompanying the reduction of the ventilation resistance. . Further, when the rear cover is used as a heat radiating member, the heat dissipation of the rear cover can be improved.

It is a fragmentary sectional view of the alternator for vehicles of one embodiment. It is the partial expanded view which looked at the rear cover from the side. It is a figure which shows the example of arrangement | positioning of the electrical component containing the rectifier which has a negative electrode side radiation fin and a positive electrode side radiation fin. It is a fragmentary sectional view around the rectifier which shows a modification. It is a fragmentary sectional view around the rectifier showing a modification in which fins are added to the rear cover side. It is a fragmentary sectional view of the VI-VI line of FIG. FIG. 6 is a partial cross-sectional view of the periphery of a rectifying device showing a modification in which a radiating fin and a rear cover are integrally molded. It is a fragmentary sectional view around the rectifier showing the modification which uses a frame as the 1st fin. It is the partial expanded view which looked at the radiation fin of the modification made into 2 steps | paragraphs from the side surface direction. It is a fragmentary sectional view around the rectifier showing a modification of the rear cover.

  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 partial sectional view of an automotive alternator according to an embodiment, and shows a sectional structure of a rear side portion. The vehicle alternator 1 shown in FIG. 1 includes a stator 2, a rotor 3, a rectifier 4, a frame 5, a rear cover 6, and the like.

  The stator 2 includes a stator core 21 and a stator winding 22 wound around the stator core 21. The rotor 3 has a structure in which a pole core 31 is passed through a rotating shaft 32 and a field winding (not shown) is sandwiched from both sides. A cooling fan 33 is attached to the axial end surface of the pole core 31 by welding or the like, and the rotor 3 rotates together with the cooling fan 33. Further, near the rear end of the rotating shaft 32, power-feeding slip rings 34 and 35 connected to the field windings are arranged. The stator 2 is disposed opposite to the rotor 3. In the above description, the field winding is provided in the rotor 3, but a brushless type configuration fixed to the frame 5 side may be employed.

  The rectifier 4 is for rectifying an AC voltage, which is an output voltage of the stator winding 22, using a rectifier element 41 to obtain a DC output power. The rectifier 4 includes heat radiation fins 42 that cool the rectifier element 41. Have. As the rectifying element 41, a diode may be used, a switching element such as a MOS-FET may be used, or a combination of a diode and a switching element may be considered. Further, the heat radiating fins 42 are formed with a first fin 43 extending in a radial direction (for example, a vertical direction) with respect to the rotation shaft 32, and are formed radially with respect to the rotation shaft 32 and the first fin 43. And a second fin 44 extending toward the rear side.

  The frame 5 accommodates the stator 2 and the rotor 3, supports the rotor 3 in a rotatable state about the rotation shaft 32, and provides a predetermined gap on the outer peripheral side of the pole core 31 of the rotor 3. The stator 2 arranged via is fixed. The frame 5 has a cooling air discharge window 51 at a portion facing the stator winding 22 protruding from the axial end surface of the stator core 21 and a cooling air suction window 52 at the inner diameter side of the axial end surface. Is provided. Specifically, as shown in FIG. 1, a bearing accommodating portion 53 that accommodates a bearing 7 that is used to support the rotor 3 in a rotatable state is formed at the center of the axial end surface of the frame 5. A plurality of suction windows 52 are formed so as to be adjacent to the outer diameter side of the bearing accommodating portion 53.

  The rear cover 6 covers the entire electrical components such as the rectifier 4, the brush device, and the IC regulator that are attached to the outside of the rear side together with the rear end portion of the rotating shaft 32 protruding to the rear side of the frame 5 to protect them. Is to do. The rear cover 6 is made of a resin material or a metal material. Aluminum or iron can be used as the metal material. In addition, as a manufacturing method using a metal material, press molding using a plate material, die casting, or the like can be considered. On the side surface of the rear cover 6, a cooling air suction window 61 is formed at a position radially outside the first fins 43 of the rectifying device 4 and on the rear side of the first fins 43. On the other hand, the rear cover 6 is not formed with a cooling air suction window on the axial end surface thereof and facing the heat dissipating fins 42 (the first fins 43 and the second fins 44).

  FIG. 2 is a partial development view of the rear cover 6 as viewed from the side. As shown in FIG. 2, a plurality of suction windows 61 having a vertically long rectangular shape are formed on the side surface of the rear cover 6 at positions on the rear side of the first fins 43. Note that the size and number of the suction windows 61 can be changed as appropriate from the viewpoint of preventing foreign matter from being mixed and ensuring the air volume.

  By the way, considering a case where a diode is used as the rectifying element 41 and the full-wave rectifying circuit is formed by being attached to the radiating fin 42 without insulation, the radiating fin 42 includes anodes of diodes as a plurality of negative-side rectifying elements 41A. Are attached in common, and negative electrode side radiation fins 42A to which cathodes of diodes as a plurality of positive side rectifying elements 41B are commonly attached are included. Then, an output terminal (not shown) is attached to a part of the positive-side radiating fin 42B.

  FIG. 3 is a diagram illustrating an arrangement example of electrical components including the rectifier 4 having the negative-side radiating fins 42A and the positive-side radiating fins 42B. As shown in FIG. 3, a negative-side heat dissipating fin 42A comprising a first fin 43A having a fan shape and a second fin 44A extending perpendicularly to the first fin 43A, and a first fan having a fan shape. One ends of the positive-side radiating fins 42B including the fins 43B and the second fins 44B extending perpendicularly to the first fins 43B are arranged adjacent to each other with a predetermined gap along the circumferential direction. The brush device 8 and the IC regulator 9 are arranged in a space formed between the other ends of the negative-side radiating fin 42A and the positive-side radiating fin 42B.

  When a diode is used as the rectifying element 41 and attached to the heat radiation fin 42 in an insulated state, the entire heat radiation fin 42 can be at the same potential, and it is not necessary to divide it into two. A structure in which the negative-side radiating fins 42A and the positive-side radiating fins 42B are integrated can be adopted.

  The same applies to the case where an element other than a diode (switching element such as a MOS-FET) is used as the rectifying element 41. When switching elements such as MOS-FETs are modularized and attached to the radiation fins 42, the entire radiation fins 42 may be at the same potential (see, for example, Japanese Patent Application Laid-Open No. 2011-151977). The entire fin 42 can be set to the same potential, and the negative-side radiating fin 42A and the positive-side radiating fin 42B shown in FIG. 3 can be integrated.

  In the vehicle alternator 1 having the above-described structure, the rotor 3 rotates in a predetermined direction when a rotational force from an engine (both not shown) is transmitted to a pulley attached to the rotary shaft 32 via a belt or the like. To do. In this state, by applying an excitation voltage to the field winding of the rotor 3 from the outside, the pole core 31 can be excited and an AC voltage can be generated in the stator winding 22, from the output terminal of the rectifier 4. DC output power is taken out.

  Further, when the cooling fan 33 rotates together with the rotor 3, the inner peripheral side thereof becomes negative pressure, and the cooling air is taken into the inside from the outside of the rear cover 6 through the suction window 61 of the rear cover 6. The cooling air taken into the rear cover 6 from the suction window 61 as the cooling fan 33 rotates in this way flows from the radially outer side to the radially inner side along the first fins 43 (43A, 43B). Further, after flowing to the cooling fan 33 side from the ventilation space 45 (FIG. 3) formed on the radially inner side of the first fin 43, it is pushed radially outward by the cooling fan 33 and from the discharge window 51 of the frame 5. Discharged. The flow of these cooling airs is indicated by an arrow F in FIG.

  As described above, in the vehicle alternator 1 of the present embodiment, the rear cover 6 has the cooling air suction window 61 formed on the side surface, and the cooling air introduced from the radially outer side of the rectifying device 4 is used as the heat radiation fin. Since it can flow along the surface of 42, the whole cooling air will contribute to cooling of the radiation fin 42, and the coolability of the rectifier 4 can be improved. Further, along with the improvement of the cooling performance of the rectifying device 4, the life of the rectifying element 41 is extended by reducing the temperature, the size of the entire generator is reduced by reducing the area of the radiating fin 42, and the cost of parts due to the use of the rectifying element 41 having low heat resistance is increased. Reduction is possible. In particular, since the cooling air suction window is not formed on the opposite end surface of the rear cover 6 corresponding to the radiating fins 42, the cooling air can be introduced only from the radially outer side of the radiating fins 42. The cooling property of the rectifier 4 can be improved reliably.

  Further, the second fins 44 are formed radially with respect to the rotation shaft 32 of the rotor 3 and extend rearward from the first fins 43, thereby increasing the surface area of the heat radiation fins 42. Therefore, the cooling performance of the rectifying device 4 can be further improved. Further, when focusing on the two second fins 44 adjacent to each other in the circumferential direction, the distance between them becomes narrower toward the inner side in the radial direction. Therefore, the wind speed of the cooling air increases toward the inner side in the radial direction, further increasing the cooling efficiency. Can be raised.

  FIG. 4 is a partial cross-sectional view around the rectifying device showing a modification. In the modification shown in FIG. 4, the second fin 44 of the radiating fin 42 constituting the rectifying device 4 has a rear side end portion in contact with the rear cover 6 along the axial direction. This eliminates the cooling air flowing through the gap between the rectifying device 4 and the rear cover 6 and allows the entire cooling air to flow through the radiation fins 42, further improving the cooling performance of the rectifying device 4 without increasing the amount of cooling air. Can be made.

  As shown in FIG. 3, when the radiating fin 42 is composed of the negative-side radiating fin 42 </ b> A and the positive-side radiating fin 42 </ b> B, a slight difference occurs depending on the material of the rear cover 6. For example, when the rear cover 6 is formed of a resin material, these can be brought into contact with the rear cover 6 regardless of the potentials of the second fins 44A and 44B.

  On the other hand, when the rear cover 6 is formed of a metal material, it is necessary to electrically insulate between the second fin 44B having the positive potential and the rear cover 6. This insulation is performed by, for example, insulating coating formed on the surface of the rear cover 6 by application or by inserting an insulating sheet having good thermal conductivity between the second fins 44B and the rear cover 6, It is conceivable to perform these simultaneously.

  Further, when the rectifying element 41 is attached to the radiating fin 42 in an insulated state, and the entire radiating fin 42 can be set to the same potential as the rear cover 6, the rear cover 6 is formed of a metal material. Even so, the entire second fin 44 can be brought into contact with the rear cover 6.

  Further, when the rear cover 6 is formed of a metal material and the end portions of the second fins 44 are in contact with each other, heat is transferred from the second fins 44 to the rear cover 6 so that the rear cover 6 can be used as a heat radiating member. . In this case, the heat dissipation can be further improved by adding fins to the rear cover 6 side.

  FIG. 5 is a partial cross-sectional view around the rectifying device showing a modification in which fins are added to the rear cover 6 side. 6 is a partial cross-sectional view taken along line VI-VI in FIG. In the modification shown in FIG. 4, the third fins 62 are formed integrally with the rear cover 6 so as to be disposed between the two adjacent second fins 44. Since the third fin 62 is cooled by the cooling air taken into the rear cover 6 from the suction window 61, the rear cover 6 serving as a heat radiating member whose temperature has been increased by heat transfer from the second fin 44 is efficiently used. Can be cooled.

  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. For example, in the above-described embodiment, the radiating fins 42 and the rear cover 6 are separate parts, but they may be integrally molded when they have the same potential. FIG. 7 is a partial cross-sectional view of the periphery of the rectifying device showing a modification in which the radiating fins 42 and the rear cover 6 are integrally molded. For example, the case where it shape | molds integrally by die casting can be considered. Thereby, the cost can be reduced by reducing the number of parts. Moreover, the heat transfer property from the radiation fin 42 to the rear cover 6 can be enhanced, and the cooling performance of the rectifying device 4 can be further improved. However, in this case, it is necessary to determine the shape and the like of the suction window 61 in consideration of the mold drawing direction. For example, it is conceivable that the second fin 44 is disposed at an intermediate position between two adjacent suction windows 61 so that the mold can be removed from the suction window 61 radially outward. Further, it is not always necessary to mold the entire radiation fin 42 and the rear cover 6 together. For example, only the negative side radiation fin 42A side shown in FIG. 3 is molded integrally with the rear cover 6, and the positive side radiation fin 42B side is formed. You may make it form with another component.

  In the above-described embodiment, the first fin 43 and the frame 5 are separate components. However, when they are at the same potential, the axial end surface of the frame 5 is used as the first fin 43. Also good. FIG. 8 is a partial cross-sectional view around the rectifying device showing a modification using the frame 5 as the first fins 43. For the attachment of the rectifying element 41 to the frame 5, a method using an adhesive or a method of press-fitting into a mounting hole formed in the frame 5 can be considered. Thereby, the cost can be reduced by reducing the number of parts. In particular, the temperature of the rectifying element 41 can be further lowered by using the frame 5 having a large heat capacity as the heat radiation fins 42. However, it is not always necessary to use the entire first fin 43 and the frame 5. For example, only the first fin 43A of the negative-side radiating fin 42A shown in FIG. The first fins 43 </ b> B of the heat radiating fins 42 </ b> B may be formed by separate parts from the frame 5.

  In the above-described embodiment, the radiating fins 42 are not stacked in the axial direction. However, a plurality of radiating fins 42 are stacked in the axial direction (for example, a two-stage configuration). Good.

  FIG. 9 is a partial development view of the heat dissipating fin 42 of the modified example having a two-stage configuration as viewed from the side. In the case of a two-stage configuration, it is conceivable that the radiation fins 42 having the same potential are overlapped with each other and the radiation fins 42 having different potentials are overlapped. The former is a case where the entire radiating fin 42 has a single potential and the two radiating fins 42 are stacked in two stages. The rectifying element 41 may be attached to only one of the heat radiating fins 42 or may be attached to both of the heat radiating fins 42. The latter is a case where the negative electrode-side heat radiation fin 42A and the positive electrode-side heat radiation fin 42B having a negative electrode potential (or ground potential) are stacked in two stages. Further, in addition to the case where a gap is provided between the heat radiating fins 42 and between the heat radiating fins 42 and the rear cover 6, these may be combined. When fins having different potentials are brought into contact with each other, it is necessary to electrically insulate them using an insulating coating or an insulating sheet.

  In the embodiment described above, the axial end surface of the rear cover 6 is a flat surface. However, the ventilation resistance may be reduced by partially inclining along the flow of the cooling air. FIG. 10 is a partial cross-sectional view around the rectifying device showing a modification of the rear cover 6. As shown in FIG. 10, the rear cover 6 is a part of the axial end surface, and is an axial position of a region facing the ventilation space 45 formed on the radially inner side of the radiating fin 42 (first fin 43). Is inclined toward the cooling fan 33 toward the inner side in the radial direction. The end of the second fin 44 of the heat dissipating fin 42 may be in contact with the rear cover 6, but a gap may be formed between them as shown in FIG. Further, the radiation fins 42 may have a plurality of stages, or the radiation fins 42 and the rear cover 6 may be molded integrally.

  In this way, by inclining a part of the rear cover 6, it is possible to prevent the cooling air from staying in the ventilation space 45 formed on the radially inner side of the radiating fin 42, thereby smoothing the flow. The cooling performance can be improved by increasing the air volume accompanying the reduction. Further, when the rear cover 6 is used as a heat radiating member, the cooling air is directly applied to the inclined portion, so that the heat dissipation of the rear cover 6 can be improved.

  In the above-described embodiment, the case where the second fin 44 is formed on the rear side of the first fin 43 has been described. However, when the amount of heat generated by the rectifying element 41 is small, the first fin The heat radiation fins 42 may be formed only by 43 and the second fins 44 may be omitted.

  As described above, according to the present invention, the cooling air introduced from the outside in the radial direction of the rectifying device 4 can flow along the surface of the radiation fin 42, so that the entire cooling air is cooled by the radiation fin 42. Thus, the cooling performance of the rectifying device 4 can be improved.

DESCRIPTION OF SYMBOLS 1 Vehicle alternator 2 Stator 3 Rotor 4 Rectifier 5 Frame 6 Rear cover 8 Brush device 9 IC regulator 32 Rotating shaft 33 Cooling fan 41 Rectifier element 42 Radiation fin 43 First fin 44 Second fin 45 Ventilation space 51 Discharge window 52 Suction window 61 Suction window

Claims (9)

A rotor that rotates together with the cooling fan; a stator that is disposed opposite to the rotor; a frame that supports the rotor and the stator; and a heat radiation fin that is fixed to the frame and cools the rectifying element. A vehicle alternator comprising a rectifier having a rear cover that covers an electrical component including the rectifier,
The heat dissipation fin has a first fin extending in a radial direction with respect to a rotation axis of the rotor,
On the side surface of the rear cover, a cooling air suction window is formed at a position radially outside the first fin and on the rear side of the first fin, and an axial end surface of the rear cover is formed. And on the facing surface corresponding to the heat radiating fin, a cooling air suction window of the heat radiating fin is not formed,
Cooling air taken into the rear cover from the suction window as the cooling fan rotates flows from the radially outer side to the radially inner side along the first fin, and further the diameter of the first fin. An AC generator for a vehicle, which flows from a ventilation space formed inside in a direction toward the cooling fan. In claim 1,
2. The vehicle alternator according to claim 1, wherein the heat dissipating fin includes a second fin that is formed radially with respect to a rotating shaft of the rotor and extends from the first fin to the rear side. In claim 2,
The second fin has a rear end along the axial direction that is in contact with the rear cover. In claim 3,
The vehicular AC generator is characterized in that the rear cover is made of a metal material. In claim 4,
The vehicular AC generator, wherein the rear cover has a third fin protruding toward the heat radiating fin. In any one of Claims 1-5,
An AC generator for a vehicle, wherein the radiating fin and the rear cover are integrally molded. In any one of Claims 1-5,
An AC generator for a vehicle, wherein an axial end surface of the frame is used as the first fin. In any one of Claims 1-6,
The AC generator for vehicles, wherein the first fins are arranged in a plurality of stages along a rotation axis of the rotor. In any one of Claims 1-8,
A part of the axial end surface of the rear cover, and an axial position of a region facing the ventilation space formed on the radially inner side of the first fin is inclined toward the cooling fan side toward the radially inner side. An AC generator for a vehicle, characterized in that

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