JP2008228488A - Ac generator for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an AC generator for vehicle, capable of enhancing the cooling performance of a rectifier, without causing increase in its size. <P>SOLUTION: In the AC generator for vehicle equipped with a rotor, a stator disposed so as to face the rotor, a frame for supporting the rotor and the stator, a rectifier 24, having a cooling fin 40 secured to the frame for cooling the rectifier and electric connection, and a cooling wind generator for suction of the cooling air on the rotor side via the cooling fin 40. The cooling fin 40 has a wall surface tilted to the rotary shaft of the rotor, along the flow of the cooling wind generated by the cooling wind generator. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

2. Description of the Related Art Conventionally, a vehicular AC generator including a rectifier including a cooling fin in which a through hole is formed in a direction parallel to a rotation axis of a rotor is known (see, for example, Patent Document 1). When the cooling fan mounted on the rotor rotates, the cooling air is sucked through the through hole, so that the cooling fins can be efficiently cooled.
Japanese Patent Laying-Open No. 2004-282937 (page 4-7, FIG. 1-10)

  Incidentally, in the vehicle alternator disclosed in Patent Document 1, the cooling air sucked by the rotation of the cooling fan mounted on the rotor is inclined along the rotation direction of the cooling fan. Since the provided through hole is formed in parallel with the rotation axis, there is a problem that the ventilation resistance increases, the wind speed decreases, and the cooling performance deteriorates. By increasing the length of the cooling fin along the rotation axis, it is possible to increase the area in contact with the cooling air, so that it is possible to improve the cooling performance, but the overall size of the vehicle alternator increases. This is contrary to the recent demands for miniaturization and weight reduction and is difficult to adopt.

  The present invention was created in view of the above points, and an object of the present invention is to provide an automotive alternator that can improve the cooling performance of a rectifier without causing an increase in physique. .

  In order to solve the above-described problems, an AC generator for a vehicle according to the present invention is fixed to a rotor, a stator disposed opposite to the rotor, a frame that supports the rotor and the stator, and the frame. A rectifier having cooling fins for cooling and electrically connecting the rectifying elements and a cooling air generator for sucking cooling air to the rotor side via the cooling fins. It has a wall surface inclined with respect to the rotation axis of the rotor along the flow of cooling air generated by the apparatus. By inclining the direction of the wall surface of the cooling fin of the rectifier according to the direction in which the cooling air is sucked, the ventilation resistance of the cooling air can be reduced. Thereby, the cooling property of a rectifier can be improved, without causing the increase in the length of the rectifier along a rotating shaft, ie, the physique of the vehicle AC generator.

  In addition, the cooling fin described above preferably includes a through hole having an opening along a plane perpendicular to the rotation axis, and the inclined wall surface is preferably a surface defining the through hole. In particular, the inclined wall surface is desirably a surface that partitions the through hole along the rotation direction of the rotor. By passing the cooling air through the inclined through hole having the wall surface inclined with respect to the rotation axis in this way, it is possible to reduce the ventilation resistance of the cooling air and increase the area of the wall surface in contact with the cooling air. Coolability can be improved.

  Moreover, it is desirable that the cooling air generator described above is a centrifugal cooling fan that rotates together with the rotor. Thereby, the air volume of the cooling air drawn into the inner fan type vehicle AC generator can be increased, and the temperature of the entire vehicle AC generator can be reduced.

  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 diagram showing an overall configuration of an automotive alternator according to an embodiment. A vehicle alternator 100 shown in FIG. 1 includes a front frame 1, a rear frame 2, a stator 4, a rotor 10, a rectifier 24, a voltage controller 25, a brush device 26, a rear cover 27, and the like. ing.

  Both the front side frame 1 and the rear side frame 2 have a bowl shape, and are fixed to each other by a plurality of bolts 3 with the stators 4 sandwiched between the openings. . The rotor 10 and the stator 4 are supported by the front side frame 1 and the rear side frame 2. A cylindrical bearing box 7 is formed integrally with the front side frame 1, and an iron bearing box 8 is attached to the rear side frame 2 with bolts 9 having knurling.

  The stator 4 is disposed to face the rotor 10 and includes a stator core 5 and a stator winding 6. The rotor 10 includes a field winding 11, pole cores 12 and 13, a rotation shaft 14, and the like, and is rotatably held by a pair of bearings 15 and 16 fixed to the bearing boxes 7 and 8. Centrifugal cooling fans 17 and 18 are attached to the axial end surfaces of the pole cores 12 and 13. The cooling fan 17 on the front side is a mixed flow type in which the blades are inclined forward with respect to the rotation direction of the rotor 10 in order to generate cooling air to the field winding 11. A pulley 19 is coupled to the front end of the rotating shaft 14 by a nut 20 and is driven to rotate by a vehicle engine (not shown). Further, a pair of slip rings 21 and 22 are provided at the rear end of the rotating shaft 14 located outside the rear side frame 2 and are electrically connected to the field winding 11.

  So-called electrical components such as the rectifier 24, the voltage control device 25, and the brush device 26 are fixed to the axial end face of the rear side frame 2 by fixing means such as bolts 9. The rectifier 24 rectifies a three-phase AC voltage, which is an output voltage of the three-phase stator winding 6, for example, and converts it into a DC output voltage. The voltage control device 25 controls the output voltage of the vehicle AC generator 100 by adjusting the excitation current flowing through the field winding 11. The brush device 26 is for passing an exciting current from the rectifier 24 to the field winding 11 of the rotor 10, and is a brush that presses each of the slip rings 21 and 22 formed on the rotating shaft 14 of the rotor 10. Is equipped.

  The rear cover 27 is a protective cover as an outer shell made of resin (for example, nylon) and covers electrical components such as a rectifier 24, a voltage control device 25, and a brush device 26 that are attached to the outside of the rear side frame 2. Protect these. The rear cover 27 is fastened and fixed to a bolt 9 extending from the rear frame 2 by a nut 28 with the rectifier 24 sandwiched therebetween.

  The rear side frame 2 has a cooling air discharge window 30 at a position facing the stator winding 6 protruding from the axial end face of the stator core 5 to the rear side (slip rings 21 and 22 side), and is axially A cooling air suction window 31 is provided on the end face. The rear cover 27 has a cooling air suction window (not shown) on the axial end surface thereof.

  In the vehicular AC generator 100 having the above-described structure, when the rotational force from the vehicle engine is transmitted to the pulley 19 via a belt or the like, the rotor 10 rotates in a predetermined direction. In this state, by applying an excitation voltage from the outside to the field winding 11 of the rotor 10, the claw portions of the pole cores 12 and 13 are excited to generate a three-phase AC voltage in the stator winding 6. A predetermined direct current is taken out from an output terminal provided in the rectifier 24. When the cooling fan 18 rotates with the rotation of the rotor 10, cooling air is sucked into the interior through the suction window of the rear cover 27. After cooling the rectifier 24 and the voltage control device 25, the cooling air is introduced into the vicinity of the cooling fan 18 through the suction window 31 of the rear frame 2 and is discharged through the discharge window 30.

  Next, details of the cooling fins provided in the rectifier 24 will be described. FIG. 2 is a perspective view showing the shape of the cooling fin provided in the rectifier 24. The cooling fin 40 provided in the rectifier 24 is fixed to the rear frame 2 for cooling and electrically connecting the rectifying element 50, and is a rotating shaft when assembled to the vehicle AC generator 100. 14 has a cylindrical shape that surrounds the periphery of 14, and includes an inner peripheral portion 41, an outer peripheral portion 42, a skewed portion 43, and a mounting portion 44.

  The inner peripheral part 41 and the outer peripheral part 42 are cylindrical members arranged concentrically with the rotary shaft 14, and a plurality of (for example, six) attachment parts 44 and skew parts so as to connect them radially. 43 is arranged. Each attachment portion 44 is formed with an attachment hole 45 used for attaching the rectifying element 50. By press-fitting the rectifying element 50 into the mounting hole 45, mechanical attachment and electrical connection of the rectifying element 50 to the attachment portion 44 are performed. Further, the skew feeding portion 43 is arranged in an inclined direction with respect to the rotating shaft 14.

  FIG. 3 is a cross-sectional view of the attachment portion 44 and the skew portion 43 along the circumferential direction, and shows a cross section of one attachment portion 44 and two skew portions 43 disposed on both sides thereof. As shown in FIG. 3, a through hole 46 having an opening along a plane perpendicular to the rotation shaft 14 is provided between the attachment portion 44 and the skew portion 43 adjacent thereto. The through hole 46 is defined by an outer peripheral surface of the inner peripheral portion 41, an inner peripheral surface of the outer peripheral portion 42, a circumferential (rotational direction) side surface 44A of the mounting portion 44, and a circumferential (rotational direction) side surface 43A of the skew portion 43. Has been.

  In these section screens, the circumferential side surface 44A of the mounting portion 44 and the circumferential side surface 43A of the skewed portion 43 form a wall surface inclined in the same direction, and the entire through hole 46 is connected to the rotating shaft 14. It is inclined in the circumferential direction with respect to the parallel direction. This inclination angle is made to coincide with the direction along the flow of the cooling air. In other words, the cooling air generated by the centrifugal cooling fan 18 serving as the cooling air generator generates the cooling air at an angle inclined with respect to the direction parallel to the rotation shaft 14 unless there is an obstacle that obstructs the flow. Inhale. In the present embodiment, the inclination angle of the through hole 46 is set so as to match (or approach) this natural suction angle.

  Thus, in the vehicle alternator 100 of the present embodiment, the direction of the wall surface of the cooling fin 40 of the rectifier 24 is inclined according to the direction in which the cooling air is sucked. Specifically, the cooling fin 24 includes a through hole 46 having an opening along a plane perpendicular to the rotation shaft 14, and a surface that partitions the through hole 46 (particularly, the through hole 46 along the rotation direction). The surface that divides the surface is inclined. Thereby, the ventilation resistance of the cooling air can be reduced, and the cooling performance of the rectifier 24 is improved without increasing the length of the rectifier 24 along the rotating shaft 14, that is, the physique of the vehicle AC generator 100. Can be made. In addition, a centrifugal cooling fan 18 is used as a cooling air generator, and the amount of cooling air sucked into the inner fan type vehicle AC generator 100 is increased to increase the overall volume of the AC generator 100 for the vehicle. The temperature can be reduced.

  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 above-described embodiment, whether the cooling fin 40 is a positive-side cooling fin or a negative-side cooling fin of the rectifier 24 is not particularly limited, but both cooling fins are illustrated from the viewpoint of improving cooling performance. The structure shown in 2 is desirable. However, any one of the cooling fins may have the structure shown in FIG.

It is a figure showing the whole composition of the alternator for vehicles of one embodiment. It is a perspective view which shows the shape of the cooling fin with which the rectifier was equipped. It is sectional drawing along the circumferential direction of an attaching part and a skew part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front side frame 2 Rear side frame 4 Stator 10 Rotor 24 Rectifier 25 Voltage control device 26 Brush device 27 Rear cover 40 Cooling fin 41 Inner peripheral portion 42 Outer peripheral portion 43 Skew portion 44 Mounting portion 45 Mounting hole 46 Through hole

Claims (4)

A rotor, a stator disposed opposite to the rotor, a frame that supports the rotor and the stator, and a cooling fin that is fixed to the frame and cools and electrically connects the rectifying element. In a vehicle AC generator comprising a rectifier and a cooling air generating device that sucks cooling air into the rotor side via the cooling fins,
The vehicular AC generator, wherein the cooling fin has a wall surface inclined with respect to a rotation axis of the rotor along a flow of cooling air generated by the cooling air generator. In claim 1,
The cooling fin includes a through hole having an opening along a plane perpendicular to the rotation axis,
The vehicle alternator according to claim 1, wherein the inclined wall surface is a surface defining the through hole. In claim 2,
The vehicle alternator according to claim 1, wherein the inclined wall surface is a surface that partitions the through hole along a rotation direction of the rotor. In any one of Claims 1-3,
The vehicle alternator according to claim 1, wherein the cooling air generator is a centrifugal cooling fan that rotates together with the rotor.

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