JP2003009465A - Alternating current generator for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an alternating current generator for a vehicle, which can improve coolingness of a diode. SOLUTION: A slip ring 34 is arranged on a rotating shaft 6 between a second bearing 18b on the side of a rear bracket 11 and a rotor 1. A brush 9 is arranged outside the rear bracket 11, where the slip ring 34 slides in contact with the brush 9 via a through hole of the rear bracket 11. The rear bracket 11 faces fan 16 on the side opposite to a pulley 7. A diode minus chill plate 21 is made to be thermally in contact with the rear bracket 11 on the outside of it and is mounted thereon, and a diode plus chill plate 22 is mounted on the outside of the rear bracket 11 while the electrical insulation between the diode minus chill plate and the diode plus chill plate is maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle alternator having a cooling function.

[0002]

2. Description of the Related Art An alternator for a vehicle, commonly called an alternator, is driven by an engine such as an internal combustion engine of the vehicle.
This is for supplying electric power to various electric components in the vehicle. Usually, the belt is driven by a pulley provided on the drive shaft of the internal combustion engine. Although the rotation speed of the internal combustion engine changes variously, the voltage that must be supplied to the electric components is a constant voltage such as 12V, so that the voltage is kept constant by adjusting the energizing current to the exciting coil.

FIG. 7 is an axial sectional view of a conventional vehicular AC generator. The rotor 1 is fixed to the rotor shaft 6 and is excited by the exciting coil 4. The rotor claws 2 generate N and S poles in the rotor circumferential direction according to the number of poles. A direct current is supplied to the exciting coil 4 by a slip ring composed of a brush 9 mainly made of carbon held in a brush holder and a brush ring 34 fixed to the rotating shaft 6. A connecting terminal 7 is placed between the slip ring 34 and the exciting coil 4, and the lead wire from the slip ring 34 and the conducting wire of the exciting coil 4 are connected here to improve the assemblability.

Although not shown, the exciting coil 4 is composed of a bobbin having an electrically insulating property, and a conductive wire having an insulating coating wound around the bobbin many times. The bobbin is made of a material with low thermal resistance to facilitate transfer of heat generated by the exciting coil to the rotor, for example, organic resin such as epoxy with dispersed aluminum oxide powder and improved thermal conductivity, or iron. A composite material in which an insulating paint or resin is coated on the surface of a metal is preferable.

Fans 15 and 16 are provided on both end surfaces of the rotor 1. Ventilation holes are formed in the front bracket 10 and the rear bracket 11 at positions communicating with the suction side and the discharge port of the fan. In the rear bracket 11, the suction side and the discharge side are structurally divided by the fan guide 33. It is necessary to make the ventilation area of both brackets 10 and 11 and fan guide 33 as large as possible so as not to provide ventilation resistance of the fan. The arrows in the figure show the ventilation paths.

The stator 1 is such that a stator coil 31 is embedded in a slot provided in a stator core 8 made of laminated steel plates. The number of slots is three times the number of poles because three-phase alternating current is generated. The stator coil 31 is formed by winding a large number of insulating coated wires, and an insulating sheet is sandwiched between the stator core and the stator core in the slot to perform insulation that also protects the insulation of the conductor. The insulated wire is preferably a square wire in order to increase the conductor wire occupation ratio of the slot. However, round wires are easier to fabricate and wind. In any case, the void in the slot is impregnated with varnish or resin to fix the conductors to each other and to easily transfer the heat generated in the coil to the stator 8. The stator core 8 is sandwiched between the front bracket 10 and the rear bracket 11, and is firmly fixed by a through bolt (not shown).

The rotating shaft 6 is rotatably supported by a bearing 18. A pulley 12 for transmitting power from the engine is provided at an end of the rotating shaft 6 on the front bracket side.
To provide. The front and rear brackets 10 and 11 are provided with support legs for fixing the alternator body to the engine. A voltage regulator 30 for adjusting the current to the exciting coil to keep the generated voltage constant regardless of the number of revolutions and a rectifier for converting the alternating current generated in the stator coil 31 into direct current are fixed to the rear bracket 11. To do.

The rectifier comprises a diode minus cooling plate 21 and a diode plus cooling plate 22 to which diodes are attached, and both cooling plates 21 and 22 are fixed to the rear bracket 11 by a fixing member 24. A thermally conductive grease or the like is applied between the diode minus cooling plate 21 and the rear bracket 11 to reduce the thermal resistance between them. The fixing member 24 fixes the diode cooling plates 21 and 22 via the mold terminal 23 that fixes the diode terminal and the stator coil lead-out portion, and the fixing member 24 and the diode cooling plates 21 and 22.
2 keeps the insulation.

FIG. 8 shows a plan view of the diode cooling plates 21 and 22 and the mold terminal 23. Between the diode minus cooling plate 21 and the diode plus cooling plate 22,
Although not shown, insert an insulating sheet. The insulating sheet is projected from both cooling plates 21 and 22 to maintain the insulation distance between the positive and negative electrodes. This insulating sheet preferably has as high thermal conductivity as possible in order to reduce the thermal resistance between the diode plus cooling plate 22 and the rear bracket 11.

The exciting coil 4, the stator coil 31, the diode 32, and the voltage regulator 30 naturally generate heat because current flows during power generation. Therefore, they must be cooled so that they do not overheat.

Conventionally, in order to remove this heat generation, air cooling is performed by fans 15 and 16 provided at the front and rear of the rotor in the axial direction, but the output of the alternator increases as the power consumption of electrical components increases. The amount of heat generated by the stator coil 31, the diode 32, and the voltage regulator 30 has been increased, which is required.

While the stator coil 4 tends to reduce the temperature relatively easily due to an increase in the fan air volume, etc., the diode 32 has a large dimensional limitation, so that the cooling means that can be used is limited and the temperature cannot be reduced. Have difficulty. Since the voltage regulator originally has a low heat generation density, it is not a thermal problem. Therefore, how to cool the diode is a key point for improving the output of the air-cooled alternator. Therefore, as in Japanese Patent Laid-Open No. 8-126274, a method has been adopted in which the diode fins are brought into thermal contact with the rear bracket to reduce the temperature.

[0013]

However, in the above method, the heat generation of the diode is not sufficiently taken into consideration in transferring the heat to the cooling air flowing around the diode cooling plate, and the diode heat generation due to the increase in the output of the alternator is not considered. There was a problem that could not be removed sufficiently.

An object of the present invention is to provide a vehicle AC generator capable of improving the cooling property of the diode.

[0015]

The present invention has a rotating shaft to which a rotational force is transmitted via a pulley, a rotor fixed to the rotating shaft and excited by an exciting coil, and both ends of the rotor. A fan on the pulley side and a fan on the side opposite to the pulley side, a stator around the rotor on which a stator coil is wound, and the stator is supported from the pulley side of the rotary shaft. A front bracket that supports the rotating shaft via a first bearing, a rear bracket that supports the stator from the side opposite to the pulley, and a rear bracket that supports the rotating shaft via a second bearing, and A slip ring that supplies an exciting current; a brush that makes electrical contact with and slides on the slip ring; a diode negative cooling plate that is electrically connected to the negative terminal of the diode; In a vehicle alternator including at least a diode plus cooling plate electrically connected to the plus terminal, the slip ring is arranged on the rotary shaft between the second bearing on the rear bracket side and the rotor. Then, the brush is arranged outside the rear bracket, and is slid on the slip ring through the through hole of the rear bracket so that the rear bracket faces the fan on the side opposite to the pulley side. The cooling plate is attached to the outside of the rear bracket while being in thermal contact therewith, and the diode plus cooling plate is attached to the outside of the rear bracket while maintaining electrical insulation from the diode minus cooling plate.

The present invention is characterized in that unevenness is provided on a surface of the rear bracket facing the fan on the side opposite to the pulley side.

The present invention is characterized in that a portion of the rear bracket facing the fan on the side opposite to the pulley side is provided with a flow path for communicating the outside and the inside of the portion.

The present invention is characterized in that the diode minus cooling plate is fitted and crimped on the rear bracket.

According to the present invention, at least 2 mm is provided between the diode plus cooling plate and the diode minus cooling plate.
It is characterized in that an interval of is provided.

In the present invention, the diode plus cooling plate is brought into surface contact with the outside of the rear bracket through an insulating sheet or an insulating spacer that maintains electrical insulation, and the diode minus cooling plate is brought into surface contact with the outside of the rear bracket. It is characterized by that.

[0021]

FIG. 1 is an axial sectional view of a first embodiment of a vehicle AC generator of the present invention. In FIG. 1, as in the conventional case, a rotor shaft 6 to which a rotational force is transmitted via a pulley 12 and an exciting coil 4 fixed to the rotor shaft.
And a fan 15 on the pulley side at both ends of the rotor and a fan 1 on the opposite side to the pulley side.
6, the stator core 8 provided on the outer circumference of the rotor and wound with the stator coil 31, and the stator core supported from the pulley side of the rotor shaft and the rotor shaft via the first bearing 18a. A front bracket 10 for supporting, a rear bracket 11 for supporting the stator iron core from the side opposite to the pulley and a rotor shaft via the two bearings 18b, a brush ring for supplying an exciting current to the rotor, and a brush. A brush 34 that is in electrical contact with and slides on the ring, a diode-minus cooling plate 21 electrically connected to the minus terminal of the diode, a diode-plus cooling plate 22 electrically connected to the plus terminal of the diode, and a voltage A regulator 30 is provided.

The difference from the prior art is that the brush ring 34 is arranged on the rotor shaft 6 between the second bearing 18b on the rear bracket 11 side and the rotor 1, and the brush 9 is arranged outside the rear bracket 11 and The rear bracket 11 is made to slide against the brush ring 34 through the through hole of the bracket 11, the rear bracket 11 is opposed to the fan 16 on the side opposite to the pulley 7, and the diode minus cooling plate 21 is brought into thermal contact with the outside of the rear bracket 11. The diode plus cooling plate 22 is attached to the outside of the rear bracket 11 while maintaining electrical insulation from the diode minus cooling plate 21.

According to this structure, the rear bracket 11 can be directly cooled by the flow generated by the fan 16.

The inside of the machine and the outside of the rear bracket 11 are connected by a fan suction port 42. As a result, a flow can be generated on the surfaces of the diode cooling plates 21 and 22, so that the diode cooling plates 21 and 22 can be efficiently cooled. The fan suction port 42 has a sufficiently large area so as not to provide ventilation resistance.

In FIG. 1, the diode plus cooling plate 22 is separated from the diode minus cooling plate 21 attached to the rear bracket 11. This is a diode plus cooling plate 2
2 prevents the fan suction port 42 from being blocked. A cover 43 having a good thermal conductivity such as aluminum is brought into thermal contact with the diode plus cooling plate 22 by an insulating sheet or the like while maintaining insulation. Thereby, the diode plus cooling plate 22 can be cooled efficiently.

In FIG. 1, the brush 9 and the voltage regulator 30 are mounted on the same side as the diode, that is, outside the rear bracket 11. Brush ring 34 and brush 9
Are brought into contact with each other through the through hole of the rear bracket 11.

By disposing the diode cooling plates 21 and 22, the brush 9 and the voltage regulator 30 as described above, it is possible to provide a vehicle AC generator which is excellent in cost and maintainability.

FIG. 2 shows a second embodiment of the vehicle alternator of the present invention.
FIG. 3 is an axial sectional view of the embodiment of FIG. In FIG.
In addition to FIG. 1, unevenness is provided on the fan 16 side of the rear bracket 11, which promotes heat transfer on the surface and further enhances the cooling effect of the fan 16 on the rear bracket 11.

FIG. 3 shows a third embodiment of the vehicle alternator of the present invention.
FIG. 3 is an axial sectional view of the embodiment of FIG. In FIG.
In addition to FIG. 1, the diode minus cooling plate 21 is attached to the mounting surface of the rear bracket 11 outside the rear bracket 11 and the fan 1.
A flow path 45 was provided to connect the suction side of No. 6 with each other. Since the fan suction port 42 is located on the center side of the rotor shaft 6, it is difficult to secure a sufficient ventilation area. Therefore, this channel 4
Compensate for the lack of ventilation area by 5. Since the inner surface of the flow path 45 itself becomes a cooling surface, it also has an effect of providing a cooling area.

FIG. 4 shows a fourth example of the vehicle alternator of the present invention.
FIG. 3 is an axial sectional view of the embodiment of FIG. In FIG.
The diode minus cooling plate 21 in FIG. 1 is fitted to the rear bracket 11. This makes it possible to sufficiently reduce the contact thermal resistance between the two, so that the cooling effect of the rear bracket 11 by the fan 16 can be efficiently transmitted to the diode cooling plates 21 and 22.

The interval δ between the diode plus cooling plate 22 and the diode minus cooling plate 21 shown in FIGS. 1 to 4 above.
Is preferably provided at least 2 mm. This is because if it is less than this dimension, the ventilation resistance of this portion becomes large, and there is a possibility that a sufficient ventilation amount cannot be secured.

FIG. 5 shows a fifth embodiment of the vehicle alternator of the present invention.
6 is an axial sectional view of the embodiment of FIG. 6, and FIG. 6 is a diode-minus cooling plate 21 and a diode-plus cooling plate 2 when viewed from the outside in the axial direction of the rear bracket 11 in FIG.
It is a figure which shows the arrangement of 2. In this embodiment, the diode plus cooling plate 22 is in direct thermal contact with the rear bracket 11. In this case, the diode plus cooling plate 22
Is in surface contact with the outer surface of the rear bracket 11 via an insulating sheet or insulating spacer that maintains electrical insulation. The diode minus cooling plate 21 is also in surface contact with the outer surface of the rear bracket 11.

As a result, the diode plus cooling plate 2
2 can be effectively cooled like the diode minus cooling plate 21. Further, since the diode cooling plate does not have a laminated structure, there is an advantage that it can be easily manufactured. This is possible if the size of the diode used is small. Therefore, when the diode is cooled according to the present invention, the diode to be used should also be selected so that the mounting space is small.

[0034]

According to the present invention, it is possible to obtain a vehicle alternator capable of improving the cooling performance of the diode.

[Brief description of drawings]

FIG. 1 is an axial sectional view of a first embodiment of a vehicle AC generator of the present invention.

FIG. 2 is an axial sectional view of a second embodiment of a vehicle AC generator of the present invention.

FIG. 3 is an axial sectional view of a third embodiment of a vehicle AC generator of the present invention.

FIG. 4 is an axial sectional view of a fourth embodiment of a vehicle AC generator of the present invention.

FIG. 5 is an axial sectional view of a fifth embodiment of a vehicle AC generator of the present invention.

6 is a view showing the arrangement of a diode minus cooling plate and a diode plus cooling plate when viewed from the outside in the axial direction of the rear bracket in FIG.

FIG. 7 is an axial sectional view of a conventional vehicle AC generator.

FIG. 8 is a plan view of a diode cooling plate and a mold terminal.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rotor, 4 ... Excitation coil, 6 ... Rotor shaft, 8 ... Stator core, 9 ... Brush, 10 ... Front bracket, 11 ... Rear bracket, 12 ... Pulley, 15, 16 ... Fan, 18
a, 18b ... Bearing, 21 ... Diode minus cooling plate, 22 ... Diode plus cooling plate, 30 ... Voltage regulator, 31 ... Stator coil, 32 ... Diode element, 34
... Brush ring, 43 ... Cover, 45 ... Flow path.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H02K 5/20 H02K 5/20 5H613 9/06 9/06 C 5H619 11/04 13/00 K 13/00 19/36 A 19/36 11/00 Y (72) Inventor Susumu Sasaki 2520 Takaba, Hitachinaka City, Ibaraki Prefecture Hitachi Ltd. Automotive Equipment Group (72) Inventor Susumu Tajima 2520 Takaba, Hitachinaka City, Ibaraki Prefecture F-terms in the Automotive Equipment Group of Hitachi, Ltd. QQ02 QQ11 QQ23 RR02 RR22 RR58 RR67 RR71 RR73 5H611 AA09 BB02 BB04 TT03 UA04 UB01 5H613 AA00 BB05 BB14 GA02 5H619 AA11 BB02 BB17 PP19 PP20 PP30 PP32

Claims (6)

[Claims] 1. A rotary shaft to which a rotational force is transmitted via a pulley, a rotor fixed to the rotary shaft and excited by an exciting coil, and a fan on the pulley side and pulleys at both ends of the rotor. A fan on the opposite side, a stator around the outer periphery of the rotor, around which a stator coil is wound, the stator is supported from the pulley side of the rotary shaft, and the first bearing is used to support the stator. A front bracket that supports the rotating shaft, a rear bracket that supports the stator from the side opposite to the pulley and also supports the rotating shaft via a second bearing, and a slip ring that supplies an exciting current to the rotor. A brush that makes electrical contact with and slides on the slip ring, a diode negative cooling plate electrically connected to the negative terminal of the diode, and a positive terminal of the diode. In the vehicle alternator including at least the diode plus cooling plate, the slip ring is arranged on the rotary shaft between the second bearing on the rear bracket side and the rotor, and the brush is the rear bracket. And sliding the slip ring through the through hole of the rear bracket so that the rear bracket faces the fan on the side opposite to the pulley side, and the diode minus cooling plate is outside the rear bracket. The vehicle alternator, wherein the diode plus cooling plate is attached to the outside of the rear bracket while maintaining electrical insulation from the diode minus cooling plate. 2. The vehicle alternator according to claim 1, wherein the rear bracket is provided with irregularities on a surface of the rear bracket that faces the fan on the side opposite to the pulley side. 3. The vehicle alternator according to claim 1, wherein a portion of the rear bracket facing the fan on the side opposite to the pulley side is provided with a flow path communicating between the outside and the inside of the portion. An alternator for vehicles, which is characterized in that 4. The vehicle alternator according to claim 1, wherein the diode minus cooling plate is fitted and crimped on the rear bracket. 5. The vehicle alternator according to any one of claims 1 to 4, wherein at least 2 mm is provided between the diode plus cooling plate and the diode minus cooling plate.
An alternating-current generator for vehicles, characterized in that a space is provided. 6. The vehicle alternator according to claim 1, wherein the diode-plus cooling plate is brought into surface contact with the outside of the rear bracket through an insulating sheet or an insulating spacer that maintains electrical insulation, and the diode-minus cooling plate. An alternator for a vehicle, wherein the rear surface of the rear bracket is in surface contact with the rear bracket.