JP2008259297A - Alternator for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an alternator for vehicle which can improve the coolability of a rectifier in fixing the negative load side heat radiating fin of the rectifier directly to a frame. <P>SOLUTION: The alternator includes a rectifier 7 which has a positive electrode side radiating fin 72 where a positive electrode side rectifying element is fixed and a negative electrode side radiating fin 74 where a negative electrode side rectifying element is fixed, and a rear side frame 5 where the rectifier 7 is attached. The positive electrode side radiating fin 72 is arranged on a side close to the rear side frame 5, and the negative electrode side radiating fin 74 is arranged in a position apart from the rear side frame 5 across the positive electrode side radiating fin 72. Part of the negative electrode side radiating fin 72 and the rear side frame 5 are coupled with each other via a stepped bolt 52, and also a through hole 80 serving as a release part corresponding to a position in which to pass this stepped bolt 52 is provided in the positive electrode side radiating fin 72. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

Conventionally, a vehicular AC generator with a large output current has a structure in which a protruding portion for directly attaching a part of a negative-side radiating fin to the frame is provided in order to reduce the ground resistance of the rectifier. (For example, refer to Patent Document 1). FIG. 5 is a partial cross-sectional view showing a rectifying device provided with a protruding portion and its peripheral structure. As shown in FIG. 5, a cylindrical convex portion 104 is provided on the frame side at a position corresponding to the protruding portion 102 of the negative-side radiating fin 100 of the rectifier, and a bolt is provided in the through hole provided in the protruding portion 102. It is fastened and fixed to the convex portion 104 through 106. The positive-side radiating fin is provided with a relief (concave portion) 110 that does not interfere with the cylindrical convex portion 104 on the frame side.
Japanese Patent Laid-Open No. 9-74727 (page 5-9, FIG. 1-12)

  Incidentally, in the vehicle alternator disclosed in Patent Document 1, it is necessary to increase the relief 110 of the positive-side radiating fin corresponding to the protruding portion 102 of the negative-side radiating fin according to the shape of the convex portion 104. If it is too large, there is a problem that the heat radiation area of the positive-side radiating fin decreases and the cooling performance deteriorates. Also, when the frame is formed by aluminum casting or die casting, the deviation between the center position of the through hole provided in the protruding portion 102 and the center position of the screw hole provided in the convex portion 104 is large. It is necessary to further increase the radiating fin relief 110, and the deterioration of the cooling performance becomes more remarkable.

  The present invention was created in view of the above points, and an object of the present invention is to improve the cooling performance of the rectifier when the negative-side radiating fin of the rectifier is directly fixed to the frame. The purpose is to provide an alternator.

  In order to solve the above-described problems, a vehicle AC generator according to the present invention includes a rectifier including a positive-side radiating fin to which a positive-side rectifying element is fixed and a negative-side radiating fin to which a negative-side rectifying element is fixed; The positive-side radiating fin is disposed on the frame side, the negative-side radiating fin is disposed at a position away from the frame across the positive-side radiating fin, A part and the frame are connected with a bolt interposed therebetween, and a relief portion corresponding to a position through which the bolt passes is provided in the positive-side radiation fin. By connecting the frame and the negative-side radiating fin using a bolt, the diameter of the connecting portion can be made smaller than when connecting using a convex portion with a screw hole on the frame side. Thereby, the escape part provided in the positive electrode side radiation fin can be made small so as not to interfere with this connecting part, and the cooling performance of the positive electrode side radiation fin and the entire rectifier can be improved by expanding the area of the positive electrode side radiation fin. it can.

  Moreover, it is preferable that the above-described relief portion is a through hole that allows the bolt to pass through a predetermined gap. As a result, it is possible to form the relief portion with a minimum area as compared with the case of the notch shape.

  Further, the above-described bolt has a stepped shape including a screw portion in which a male screw groove is formed and a pedestal portion having a diameter larger than that of the screw portion, and a negative-side radiating fin is provided on an end surface in the axial direction of the pedestal portion. The connection between the negative-side radiation fin and the frame may be performed by tightening the other surface of the negative-side radiation fin using a nut that is screwed into the threaded portion while the one surface is in contact. desirable. This facilitates positioning of the negative-side heat dissipating fins and eliminates the need for a separate member when fixing the protruding portion to the bolt using a nut, thereby reducing the number of parts.

  Hereinafter, an automotive alternator as a vehicular rotating electrical machine 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 showing the overall structure of an automotive alternator according to an embodiment. As shown in FIG. 1, the vehicle alternator 1 of this embodiment includes a rotor 2, a stator 3, a front side frame 4, a rear side frame 5, a brush device 6, a rectifier 7, a voltage regulator 8, It includes a pulley 9 and the like.

  The rotor 2 includes a field winding 21 in which an insulated copper wire is wound in a cylindrical and concentric manner, and both sides of the rotor 2 through a rotating shaft 24 by field cores 22 and 23 each having six claws. It has a structure sandwiched between. A cooling fan 25 for discharging the cooling air sucked from the front side in the axial direction and the radial direction is attached and fixed to the end surface of the field core 22 on the front side (pulley 9 side) by welding or the like. Similarly, a cooling fan 26 for discharging the cooling air sucked from the rear side in the radial direction is attached and fixed to the end surface of the rear side field core 23 by welding or the like. The stator 3 includes a stator core 31 and a three-phase stator winding 32.

  The rectifier 7 is for rectifying the three-phase alternating current that is the output voltage of the three-phase stator winding 32 of the stator 3 to obtain a direct current output, and is a positive-side radiation fin fixed at a predetermined interval. And a negative-side radiating fin and a plurality of rectifying elements attached to the respective radiating plates by soldering or the like. Details of the rectifier 7 will be described later.

  The front side frame 4 and the rear side frame 5 accommodate the rotor 2 and the stator 3 described above, and the rotor 2 is supported in a state where the rotor 2 can rotate around the rotation shaft 24. The stator 3 is disposed outside the field cores 22 and 23 via a predetermined gap. The stator 3 is fixed by tightening bolts 34 to four support portions 420 provided at equal intervals along the rotation direction of the rotor 2.

  The voltage regulator 8 is for adjusting the output voltage of the vehicular AC generator 1 by controlling the exciting current that flows through the field winding 21, and the output varies depending on the electric load and the power generation amount. Keep the voltage almost constant. The pulley 9 is for transmitting the rotation of the engine (not shown) to the rotor 2 in the vehicular AC generator 1, and a nut 91 is attached to one end (the side opposite to the slip ring) of the rotating shaft 24. Tightened and fixed. A rear cover 10 that protects the brush device 6, the rectifying device 7, and the voltage regulator 8 is attached. The rear cover 10 is fastened and fixed by a nut 11 to a bolt 51 extending from the rear side frame 5 with the rectifying device 7 interposed therebetween.

  Next, the rectifier 7 and its peripheral structure will be described in detail. FIG. 2 is a partial enlarged cross-sectional view in the vicinity of the rectifier 7. FIG. 3 is a rear view of the rectifier 7 and shows a shape viewed from the rear frame 5 side. FIG. 4 is a plan view showing a partial shape of the negative-side radiating fin included in the rectifier 7, and shows a shape seen from the rear cover side.

  The rectifying device 7 is attached to the positive-side radiating fins 72 and the negative-side radiating fins 74 that are stacked so as to be opposed to each other in the axial direction with the insulating member 71 interposed therebetween, and is attached to the positive-side radiating fins 72 by soldering or the like. Positive electrode side rectifying element 73, negative electrode side rectifying element 75 attached to negative electrode side radiating fin 74 by soldering or the like, and electricity between positive electrode side rectifying element 73 and negative electrode side rectifying element 75 and stator winding 32 And a terminal block 77 having a built-in terminal 76.

  The positive-side radiating fins 72 are arranged on the pulley side (closer to the rear-side frame 5) than the negative-side radiating fins 74, that is, the rear-side frame 5, the positive-side radiating fins 72, and the negative-side radiating fins 74 are arranged in this order. . The inner diameters of the positive-side radiating fin 72 and the negative-side radiating fin 74 are substantially equal, and the negative-side radiating fin 74 has a smaller outer diameter. The negative electrode side heat radiation fin 74 has a protruding portion 78 in which a part of the outer periphery is protruded to the outer diameter side. A through hole 79 is formed in the protruding portion 78. The outer diameter of the protruding portion 78 is substantially equal to the outer diameter of the positive-side radiating fin 72, and the positive-side radiating fin 72 at a position corresponding to the protruding portion 78 has a larger diameter than the through-hole 79 of the protruding portion 78. A hole 80 is provided.

  In addition to the bolts 51 used for fastening the rear cover 10, stepped bolts 52 that extend rearward in the axial direction are attached to the rear frame 5. The stepped bolt 52 includes a screw part 52A at a tip end where a male screw groove is formed, and a cylindrical pedestal part 52B having a diameter larger than that of the screw part 52A. The pedestal 52B is passed through the through hole 80 of the positive-side radiating fin 72 with a gap interposed therebetween, and the screw 52A is passed through the through-hole 79 of the protruding portion 78 to the axial end surface of the pedestal 52B. One surface of the negative-side radiating fin 74 is brought into contact, and the other surface of the negative-side radiating fin 74 is tightened using the nut 12 screwed into the screw portion 52A, whereby the negative-side radiating fin 74 and the rear-side frame 5 are tightened. Is connected via a stepped bolt 52.

  Thus, in the vehicle alternator 1 of this embodiment, the rear side frame 5 and the negative side heat radiation fin 74 are connected by using the stepped bolt 52, so that the connection is made by using the convex portion with the screw hole. Compared with the case where it does, the diameter of this connection part (stepped bolt 52) can be made small. Thereby, the escape part provided in the positive electrode side radiation fin 72 can be made small so that it may not interfere with this connection part, and the cooling property of the positive electrode side radiation fin 72 and the whole rectifier 7 by the area expansion of the positive electrode side radiation fin 72 is improved. Can be improved.

  Further, by providing the escape portion with the through hole 80 that allows the stepped bolt 52 to pass through a predetermined gap, it is possible to form the escape portion with a minimum area as compared with the case of the notch shape. . Further, the use of the stepped bolt 52 facilitates the positioning of the negative side heat dissipating fin 74, and a separate member becomes unnecessary when the protruding portion 78 is fixed to the stepped bolt 52 using the nut 12. The score 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, the stepped bolt 52 is used. However, when an increase in the number of parts is allowed, a tubular member is arranged around the bolt to fix the negative-side radiating fin 74 in the axial direction. Also good. In addition, the positive hole radiating fin 72 is provided with the through hole 80 as a relief portion, but may be a relief portion having a notch shape that is a recess from the outer diameter (or inner diameter).

It is sectional drawing which shows the whole structure of the alternating current generator for vehicles of one Embodiment. It is a partial expanded sectional view of the rectifier vicinity. It is a reverse view of a rectifier. It is a top view which shows the partial shape of the negative electrode side radiation fin contained in a rectifier. It is a fragmentary sectional view of the conventional rectifier and its peripheral structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle alternator 2 Rotor 3 Stator 4 Front side frame 5 Rear side frame 6 Brush device 7 Rectifier 8 Voltage regulator 9 Pulley 10 Rear cover 11, 12 Nut 52 Stepped bolt 52A Screw part 52B Base part 71 Insulation Member 72 Positive-side radiating fin 73 Positive-side rectifying element 74 Negative-side radiating fin 75 Negative-side rectifying element 77 Terminal block 78 Protruding portion 79, 80 Through hole

Claims (3)

In a vehicle AC generator comprising a rectifier having a positive-side radiating fin to which a positive-side rectifying element is fixed and a negative-side radiating fin to which a negative-side rectifying element is fixed, and a frame to which the rectifier is attached,
The positive-side radiating fin is disposed on the frame side, and the negative-side radiating fin is disposed at a position away from the frame across the positive-side radiating fin,
A vehicle AC characterized in that a part of the negative-side radiating fin and the frame are connected via a bolt, and a relief portion corresponding to a position where the bolt is passed is provided in the positive-side radiating fin. Generator. In claim 1,
The vehicle alternator according to claim 1, wherein the relief portion is a through hole that allows the bolt to pass through a predetermined gap. In claim 1 or 2,
The bolt has a stepped shape including a screw portion in which a male screw groove is formed and a pedestal portion having a diameter larger than the screw portion,
By tightening the other surface of the negative electrode side radiation fin using a nut screwed to the screw portion in a state where one surface of the negative electrode side heat radiation fin is in contact with the axial end surface of the pedestal portion, The vehicle alternator is characterized in that the negative-side radiating fin and the frame are connected.

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