JP2008035660A - Rectifying device of alternator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rectifying device of an alternator with which assembly work is facilitated while reliability is secured. <P>SOLUTION: An arcuate notch 61a whose diameter is equal to an outer diameter of a lower arm-side diode 64 is arranged at a peripheral edge of a +fin 61 close to a negative lead 64a of the lower arm-side diode 64 fixed to a -fin 62 of a rear frame 1-side. A barrier between the negative lead 64a and the +fin 61 is omitted from a resin cover 5 which is conventionally installed. Thus, electric insulation and reliability can be improved, and assembly work becomes simple. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rectifier for a vehicle AC generator mounted on a passenger car, a truck, and the like, and more particularly, to an improvement in the shape of a cooling fin.

  The AC generator rectifier of a vehicle is equipped with positive and negative heat sinks (hereinafter also referred to as + fins and -fins) that extend in the radial direction at predetermined intervals in the axial direction in a posture facing the frame end face. is doing. The upper arm side diode is attached to the + fin, and the lower arm side diode is attached to the − fin so as to face each other. Since the frame is at ground potential, the −fin is usually disposed on the end face side of the axial direction frame, and the + fin is disposed on the resin cover (also referred to as a rear cover) covering the rectifier. The fin is usually fixed to the frame end surface of the same potential, but the lower arm side diode is also directly fixed to the frame end surface also serving as the fin.

  Each diode includes a bottomed cylindrical electrode terminal, a diode element having a bottom electrode surface fixed to the bottom of the bottomed cylindrical electrode terminal, and a bottom cylindrical electrode terminal fixed to the top electrode surface of the diode element. The lead electrode terminal protrudes along the central axis on the opening side, and a necessary portion is filled with a resin for insulation protection and integration. Hereinafter, this type of diode structure is referred to as a one-side lead structure.

  As is well known, the + fin and the −fin are each made of a substantially horseshoe-shaped (substantially U-shaped plate) and a highly conductive metal plate extending around the rotation axis. A regulator is arranged. That is, the + fin and the -fin are designed to occupy as much as possible a space where no other electrical component exists (hereinafter also referred to as an electrical component chamber) at a position overlapping with the other electrical component in the axial direction. . This is to increase the heat radiation area of the + fin and −fin in order to reduce the temperature of the diode element, which is a power semiconductor element, as much as possible.

  In view of the necessity of increasing the heat radiation area, the + fin is normally disposed so as to overlap the lower arm side diode fixed to the −fin as viewed in the axial direction. However, if the overlap between the + fin and the lower arm side diode in the radial direction is too large, there is a risk that the + fin will short-circuit with the lead of the lower arm diode that protrudes toward the + fin side. A radial clearance between the arm-side diode leads must be ensured. For this reason, conventionally, a partition wall portion is projected in the axial direction from the resin cover between the peripheral portion of the + fin and the lead of the lower arm side diode. Hereinafter, this structure is referred to as a partition wall insertion structure. This partition wall insertion prevents the peripheral edge of the + fin and the lower arm side diode lead from coming into contact with each other even if an impact or water droplet intrusion occurs.

  However, the present inventors have found that such a partition wall-inserting structure using the resin cover with a partition wall includes the following problems. That is, the assembling work of the resin cover with a partition wall portion is as follows. After the rectifier is assembled to the frame end surface, the resin cover with the partition wall portion is fitted in the axial direction, and then the resin cover with the partition wall portion is fastened to the frame end surface. Made.

  However, when the partition of the resin cover is fitted between the peripheral edge of the fin and the lead of the lower arm side diode, the tip of the thin partition wall collides with a waterproof soft rubber material covering the lower arm side diode. It has been found that there is a possibility of damaging it and thereby deteriorating its waterproofness. Further, it was found that the thin partition wall portion may come into contact with the bend portion of the lead of the lower arm side diode at the time of fitting, and hinder movement such as displacement absorption due to thermal expansion. Further, it has been found that such an interposition of the partition wall deteriorates the flow of the cooling air flow in the vicinity of the lower arm side diode.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a rectifier for a vehicle alternator that can facilitate assembly work while ensuring reliability.

  In the present invention for solving the above-mentioned problems, the peripheral portion of the + fin is an arc-shaped notch that bypasses the negative lead around the negative lead with a radius of curvature substantially equal to the outer circumference of the lower arm side diode. And the resin cover does not include a partition wall protruding between the notch and the negative lead. In addition, the curvature radius of substantially equal diameter said here shall be the range of 0.8 to 1.2 times the outer diameter of a lower arm side diode.

  That is, the rectifying device of the present invention is characterized in that the + fin has an arc-shaped notch that bypasses the lead of the lower arm side diode. In this way, since the distance from the negative lead to each part of the notch is substantially equal, the peripheral edge of the + fin and the negative lead are avoided from being abnormally close to each other in the vicinity of the negative lead. + Fins can be extended. As a result, the partition area is not provided between the + fin and the negative lead while securing the required area of the + fin, so that the soft rubber for protecting the lower arm side diode may be damaged during the partition section installation work. Necessary and sufficient electrical insulation performance between the two can be ensured while preventing the negative lead from contacting the bend portion and hindering its movement. Furthermore, the cooling air flow at this portion can be remarkably improved, and the cooling performance of the lower arm side diode and the + fin can be improved.

  In a preferred embodiment, the diode includes a bottomed cylindrical fin fixed side electrode, a diode element having a first electrode surface fixed to the fin fixed side electrode, and a second electrode surface fixed to the diode element. A lead electrode that protrudes along the axis of the fin fixing side electrode; an insulating resin portion that seals the diode element and secures a predetermined radial insulation distance dx between the fin fixing side electrode and the lead electrode; The radial insulation distance d between the notch and the negative lead is separated from the surface of the negative lead by 1 to 1.2 times the radial insulation distance dx in the radial direction. In the state, the negative lead is bypassed over at least 1/3 of the entire circumference of the lower arm side diode. In this way, the cutout portion sufficiently surrounds the lower arm side diode and extends in the radial direction, so that the area of the + fin can be increased and its cooling performance can be improved.

  More specifically, the negative lead is connected to the lead wire of the stator coil through the relay electrode body. Therefore, the notch portion of the + fin can surround the negative lead as much as possible in an arc shape within a range in which an insulation distance with respect to the relay electrode body connected to the negative lead can be secured. Specifically, it is preferable that the arc-shaped notch is arranged in a range of 1/3 to 2/3 of the entire circumference of the lower arm side diode lead. Also, the electrical insulation performance between the + fin notch and the negative lead should be equal to or greater than the electrical insulation performance (when the diode is off) between the negative lead and the fin fixed side electrode of the lower arm diode. Therefore, the partition wall can be omitted without any problem. In addition, since the radial insulation distance between the notch and the negative lead is equal to or greater than the radial insulation distance dx between the negative lead and the fin fixing side electrode of the lower arm side diode, tolerance in manufacturing and assembly is reduced. It can be ensured, and manufacturing assembly becomes easy.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a rectifier for a vehicle AC generator according to the invention will be described with reference to the drawings.

(Embodiment 1)
The vehicle alternator of Embodiment 1 will be described below.

(overall structure)
First, a vehicular AC generator equipped with the rectifier of this embodiment will be briefly described with reference to a schematic sectional view in the axial direction shown in FIG.

  1 is a bowl-shaped rear frame, and 2 is a bowl-shaped front frame, which are fastened by through bolts to sandwich the stator 3 in the axial direction. The rear frame 1 and the front frame 2 support the rotation shaft of the Landel rotor 4 via bearings. A resin cover 5 is fixed to the rear frame 1, and the resin cover 5 surrounds the rear end surface of the rear frame 1 and forms an electrical component chamber therein.

  A rectifier 6, a brush 7, and a regulator 8 are arranged in the electrical component chamber. The brush 7 is positioned immediately above the rotation shaft and fixed to the rear frame 1 and is in sliding contact with a slip ring fixed to the rotation shaft. The regulator 8 is positioned above the brush 7 and is fixed to the rectifier 6. .

  The rectifying device 6 is fixed to the rear frame 1 at a position overlapping the brush 7 and the regulator 8 in the axial direction, and extends into a horseshoe-shaped space not occupied by the brush 7 and the regulator 8 in the electrical component chamber. ing. The rectifier 6 includes a + fin (positive heat radiating plate) 61, a −fin (negative heat radiating plate) 62, an upper arm side diode 63, a lower arm side diode 64, and a terminal block 65.

  Since the operation itself of the vehicle alternator described above is already known, the description thereof is omitted.

(Rectifier 6)
The basic structure of the rectifier 6 will be described with reference to FIGS. 2 is an axial cross-sectional view in which a portion near the rectifying device 6 in FIG. 1 is enlarged, and FIG. 3 is a front view showing the rectifying device 6 viewed from the axial rear side.

  The upper arm side diode 63 is press-fitted into the diode press-fitting hole of the + fin 61, the lower arm side diode 64 is press-fitted into the diode press-fitting hole of the −fin 62, and the + fin 61, −fin 62 and the resin cover 5 are inserted into the rear frame 1. It is concluded. However, the -fin 62 is fastened to the rear frame 1 so as to be conductive, but the + fin 61 is fastened by being electrically insulated from the rear frame 1 by a known electrically insulating fastening mechanism such as an insulating sleeve. Reference numeral 66 denotes an electrically insulating cylinder portion for securing an axial distance between the + fin 61 and the resin cover 5.

  The upper arm side diode 63 has a lead electrode terminal 63a that forms a cathode, and the lead electrode terminal 63a extends forward in the axial direction. The leading end portion of the lead electrode terminal 63a reaches the intake hole 1a of the rear frame 1 over the −fin 62 in the axial direction. The lower arm side diode 64 has a lead electrode terminal 64a forming an anode, and the lead electrode terminal 64a extends rearward in the axial direction. The tip end portion of the lead electrode terminal 64a reaches the vicinity of the inner end face of the resin cover 5 beyond the + fin 61 in the axial direction. 63b is a bend portion of the lead electrode terminal 63a, and 63c is an insulating rubber portion made of silicon rubber that covers the end surface of the upper arm side diode 63 on the lead electrode side. 64b is a bend portion of the lead electrode terminal 64a, and 64c is an insulating rubber portion made of silicon rubber that covers the end surface of the lower arm side diode 64 on the lead electrode side. As is well known, the anode of the upper arm side diode 63 for three phases is fixed to the + fin 61, and the cathode of the lower arm side diode 64 for three phases is fixed to the -fin 62. 61 is connected to the positive side of the battery, and -fin 62 is connected to the negative side of the battery. The lead electrode terminal 63a of the upper arm side diode 63 and the lead electrode terminal 64a of the lower arm side diode 64, which are in phase with each other, are connected to the in-phase axial lead wire of the stator coil through the relay electrode plate, and the three-phase full wave A rectifier is configured. Since the other configuration and operation of the rectifier 6 that constitutes the three-phase full-wave rectifier are the same as in the past, the description thereof is omitted.

  As shown in FIG. 3, horseshoe-shaped + fins 61 and −fins 62 overlap each other at a predetermined interval when viewed in the axial direction at the same position in the circumferential direction. 3, 67 is an output terminal (B terminal) fixed to one end of the + fin 61, 68 is a through-hole through which a fastening bolt 69 for fastening the + fin 61 and the −fin 62 to the rear frame 1 is inserted, Reference numeral 70 denotes an air flow hole for allowing the cooling air flow to penetrate in the axial direction. The three upper arm side diodes 63 press-fitted into the + fins 61 and the three lower arm side diodes 64 press-fitted into the −fins 62 are distributed at different positions in the circumferential direction.

  The diode 100 used as the upper arm side diode 63 and the lower arm side diode 64 will be described with reference to FIG. FIG. 4 is a schematic axial sectional view of the diode 100. The diode 100 includes a bottomed cylindrical fin fixed side electrode 101, a diode element 103 having a first electrode surface fixed to the fin fixed side electrode 101 through a buffer metal plate 102, and a second electrode surface fixed to the diode element 103. The lead (lead electrode) 104 protruding along the axial center of the fin fixed side electrode 101 and the diode element 103 are sealed, and a predetermined radial insulation distance dx is provided between the fin fixed side electrode 101 and the lead 104. And an insulating resin portion 105 for ensuring the above.

(Spatial relationship between lead electrode terminal 64a and peripheral edge of fin 61)
Next, the spatial relationship between the lead electrode terminal 64a and the peripheral edge of the + fin 61, which are characteristic features of this embodiment, will be described with reference to FIG. FIG. 5A is a schematic enlarged front view of the vicinity of the lower arm side diode 64 showing that of this embodiment viewed from the axial rear side, and FIG. 5B is a conventional lower arm side diode shown for comparison. It is the model expansion front view which looked at 64 vicinity from the axial direction rear side. In this specification, the lead electrode terminal 64a of the lower arm side diode 64 may be abbreviated as a negative lead.

  In FIG. 5A, the peripheral edge of the + fin 61 is an arcuate cut that bypasses the negative lead 64a around the negative lead 64a with a radius of curvature d substantially equal to the outer peripheral surface 64d of the lower arm side diode 64. It has a notch 61a. The arc-shaped notch 61a is disposed around the negative lead 64a along the outer peripheral surface 64d of the lower arm side diode 64 by an angle θ about the negative lead 64a. The angle θ is 120 to 240 degrees.

(effect)
The advantages of the arcuate cutout 61a of this embodiment will be described below.

  For comparison, the shape of the peripheral edge portion 61b of the + fin 61 in the vicinity of the conventional negative lead 64a is shown in FIGS. In the conventional rectifier 60, as shown in FIG. 5B, the peripheral edge portion 61b of the + fin 61 in the vicinity of the negative lead 64a has a linear shape. This is to simplify the work of inserting the electrically insulating partition wall 5a between the negative lead 64a and the peripheral edge 61b of the + fin 61. A conventional rectifier 60 having the structure of FIG. 5B is shown in FIGS. FIG. 8 is a schematic axial sectional view of the vicinity of a rectifier 60 of a conventional vehicle alternator, and FIG. 9 is a front view of the conventional rectifier 60 as viewed from the axial rear side.

  As apparent from these drawings, conventionally, a linear partition wall portion 5a is projected from the inner end surface of the resin cover 5 to the front side in the axial direction. In FIG. 9, the partition wall 5a is not shown. The partition wall portion 5a is inserted between the negative lead 64a and the peripheral edge portion 61b of the + fin 61, and its tip reaches the vicinity of the bend portion 64b of the negative lead 64a. The arrangement of the partition wall 5a can improve the electrical insulation between the negative lead 64a and the peripheral edge 61b of the + fin 61, and the lower arm side diode 64 and the + fin only by the area shown by hatching in FIG. 61 can be overlapped with each other in the radial cross section, and the cooling area of the + fin 61 can be gained.

  On the other hand, in this embodiment shown in FIG. 5A, an arc-shaped notch 61a having a diameter substantially equal to the outer diameter of the lower arm side diode 64 is provided at the peripheral portion of the + fin 61. However, the partition wall portion 5a shown in FIG. As a result, a necessary and sufficient electrical insulation performance can be ensured between the + fin 61 and the negative lead 64a, and the partition wall portion 5a of the resin cover 5 can be made narrower as in the conventional case by the peripheral edges of the negative lead 64a and the + fin 61. Since it is not necessary to insert between these parts, the mounting operation of the resin cover 5 can be greatly simplified. Further, when the operator attaches the resin cover 5, the tip of the partition wall 5a is accidentally collided with the bend portion 64b of the negative lead 64a, the insulating rubber portion 64c for sealing, and the like, and the above-described obstacles are given to these functions. There is nothing.

  However, if the arc-shaped cutout portion 61a shown in FIG. 5A is provided, there is a problem that the cooling area of the + fin 61 is reduced by that amount. In this embodiment, FIG. Since the area of the + fin 61 shown by hatching increases compared to FIG. 5B, it has been found that the decrease in the cooling area of the + fin 61 is practically negligible.

  Next, it will be further described that the necessary and sufficient electrical insulation performance can be ensured between the + fin 61 and the negative lead 64a only by forming the arc-shaped notch 61a. The voltage between the + fin 61 and each negative lead 64a is equal to the voltage when the upper arm side diode 63 is off. As shown in FIG. 4, the distance dx between the cylindrical electrode terminal 101 with the bottom of the diode 100 and the lead 104 is set to withstand the voltage between them. Therefore, by making the diameter d of the arc-shaped cutout portion 61a substantially equal to the outer diameter r of the lower arm side diode 64, the necessary electrical insulation performance between them can be ensured. More specifically, the distance dx is equal to the radial distance between the inner diameter of the bottomed cylindrical electrode terminal 101 and the outer diameter of the negative lead 64a and is smaller than the outer diameter of the lower arm side diode 64.

  Preferably, the radial insulation distance d between the arcuate notch 61a and the negative lead 64a is 1 to 1.2 times the radial insulation distance dx. is there.

(Embodiment 2)
The vehicle alternator of Embodiment 2 will be described below with reference to FIG.

  The + fin of this embodiment shown in FIG. 6 has a peripheral portion 61b having the same shape as the peripheral portion 61b of the conventional + fin 61 shown in FIG. 5 (b). However, in this embodiment, the insulating resin film 200 is applied to the area shown by hatching in FIG. The insulating resin film 200 is preferably formed on the side surface, upper surface, and lower surface in the vicinity of the peripheral edge portion 61b of the + fin 61, and may be formed by coating or may be formed by film adhesion. The insulating resin film 200 exhibits an electrical insulating function equivalent to that of the partition wall portion 5a due to its excellent electrical insulation.

  The shape of the peripheral edge portion 61b of the + fin 61 is not required to be a linear shape but is arbitrary, but it is necessary to provide an arc-shaped notch portion 61a as in the first embodiment shown in FIG. There is no.

(Embodiment 3)
The vehicle alternator of Embodiment 3 will be described below with reference to FIG.

  The + fin of this embodiment shown in FIG. 7 has a peripheral portion 61b having the same shape as the peripheral portion 61b of the conventional + fin 61 shown in FIG. 5 (b). However, in this embodiment, an insulating resin molded body 300 having a U-shaped cross section is fitted and bonded to a portion of the peripheral edge portion 61b of the + fin 61 that is close to the negative lead 64a. If it does in this way, the electrical insulation function equivalent to the partition part 5a can be show | played by the excellent electrical insulation of the insulating resin molding 300. FIG.

(Modification)
When the insulating resin film 200 and the insulating resin molded body 300 are attached to the arc-shaped notch 61a having the shape shown in FIG. 5A, the distance between the arc-shaped notch 61a and the negative lead 64a is set. Further reduction can be achieved.

FIG. 3 is a schematic cross-sectional view in the axial direction of the vehicle alternator of Embodiment 1. FIG. 2 is an axial sectional view in which a portion near the rectifier in FIG. 1 is enlarged. It is a front view which shows the state which looked at the rectifier of FIG. 1 from the axial direction rear side. It is a model axial sectional view of a diode. It is a figure which shows the spatial relationship between the lead electrode terminal of a lower arm side diode, and the periphery of + fin, FIG.5 (a) is the model enlarged front view which looked at the lower arm side diode vicinity of this Example from the axial direction rear side. FIG. 5 (b) is a schematic enlarged front view of the vicinity of the conventional lower arm side diode shown for comparison from the rear side in the axial direction. 6 is a schematic enlarged front view of the vicinity of a lower arm side diode of Embodiment 2 as viewed from the axial rear side. FIG. 6 is a schematic enlarged axial sectional view in the vicinity of a lower arm side diode of Embodiment 3. FIG. It is a typical axial sectional view near the rectifier of the conventional vehicle alternator. It is the front view which looked at the conventional rectifier from the axial direction rear side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a Air intake hole 1 Rear frame 2 Front frame 3 Stator 4 Landel type rotor 5 Resin cover 5a Bulkhead part 6 Rectifier 7 Brush 8 Regulator 60 Rectifier 61 + Fin 61a Notch 61b Peripheral part 62-Fin 63 Upper arm side diode 63a Lead electrode terminal 64 Lower arm side diode 64a Lead electrode terminal (negative lead)
65 Terminal Block 69 Fastening Bolt 100 Diode 101 Fin Fixed Side Electrode 102 Buffer Metal Plate 103 Diode Element 104 Lead 105 Insulating Resin Part 200 Insulating Resin Film 300 Insulating Resin Molded Body

Claims (2)

An approximately horseshoe-shaped + fin and −fin extending in a radial direction at predetermined intervals in the axial direction along the end face of the frame, an upper arm side diode fixed to the + fin, and the −fin A rectifier having a lower arm side diode fixed;
A bowl-shaped resin cover fixed to the frame and surrounding the rectifier while facing the + fin;
With
In the vehicle alternator in which the positive lead that is the lead electrode of the upper arm side diode extends in the axial direction −fin direction, and the negative lead that is the lead electrode of the lower arm side diode extends in the axial direction + fin direction,
The peripheral edge of the + fin has an arc-shaped notch that bypasses the negative lead around the negative lead with a radius of curvature substantially equal to the outer periphery of the lower arm diode,
The vehicle alternator according to claim 1, wherein the resin cover does not include a partition wall protruding between the notch and the negative lead. In the vehicle alternator according to claim 1,
The diode includes a bottomed cylindrical fin fixed side electrode, a diode element having a first electrode surface fixed to the fin fixed side electrode, and a fin fixed side electrode fixed to the second electrode surface of the diode element. A lead electrode that protrudes along the axis of the electrode, and an insulating resin portion that seals the diode element and secures a predetermined radial insulation distance dx between the fin fixing side electrode and the lead electrode,
The radial insulation distance d between the notch and the negative lead is 1 to 1.2 times as long as the radial insulation distance dx and is separated from the surface of the negative lead in the radial direction. An automotive alternator that bypasses the negative lead over at least 1/3 or more of the entire circumference of the lower arm side diode.

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