JP3982415B2 - AC generator for vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle AC generator mounted on a passenger car, a truck, or the like.
[0002]
[Prior art]
In a general vehicle AC generator, a rectifier is built in to rectify the AC induced voltage generated in the stator winding wound around the stator core when the rotor is rotated. Yes. When the stator winding is composed of three phases, a total of six pieces, two for each phase winding, or a total of eight pieces when taking out the neutral point output connecting each phase of the three-phase winding A rectifier including the rectifier element is provided, and three-phase full-wave rectification is performed by this rectifier.
[0003]
2. Description of the Related Art Conventionally, a vehicular AC generator in which a part of a terminal block included in such a rectifier device is extended in the direction of a rotating shaft of a rotor to prevent the occurrence of poor insulation is known (for example, , See Patent Document 1). The rectifier used in this vehicle alternator extends from the terminal block in the direction of the rotor axis even if foreign matter such as water or electrolyte enters the vehicle alternator from the rear side. By forming the drainage channel with the extended part, it is possible to prevent foreign matter such as electrolyte entering the heat sink from staying near the joint between the stator winding and the rectifier. It is possible to reduce insulation defects that occur in the apparatus.
[0004]
[Patent Document 1]
JP 2001-37143 A (page 4-6, FIG. 1-6)
[0005]
[Problems to be solved by the invention]
By the way, the vehicle alternator disclosed in Patent Document 1 described above is for preventing the occurrence of insulation failure in the rectifying device, and since there is no particular measure for the cooling air flow, In order to realize temperature reduction as well as prevention, there is a problem that the cooling air flow may be insufficient.
[0006]
Generally, as a cooling method for the rectifier, the distance between the rear cover and the rectifier is shortened, and the position of the opening of the rear cover is made to correspond to the position of each rectifier of the rectifier, thereby locally cooling each rectifier. A method of improving the cooling performance of the rectifier can be considered, but in this case, the overall cooling air volume decreases due to the increase of the ventilation resistance, and the temperature of the bearing accommodated in the stator winding and the rear frame increases. Inconvenience occurs. In addition, there is a method to increase the number of openings by increasing the rear cover in order to increase the cooling air volume, but the size of the vehicle alternator becomes larger, and it tends to interfere with other parts when mounted on the vehicle. New inconvenience arises.
[0007]
The present invention was created in view of the above points, and an object of the present invention is to provide an automotive alternator capable of preventing the occurrence of poor insulation in the rectifier and increasing the amount of cooling air. Is to provide.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problems, an AC generator for a vehicle according to the present invention rotates a rotor, a stator having a stator winding that induces an AC voltage when the rotor is rotated, and the rotor. A frame that is supported in a possible state; a rectifier that is attached to the outside of the frame and rectifies an AC voltage induced in the stator winding; and a rear cover that covers the rectifier from the outside. Along the outer diameter side end face disposed at a position close to the rotor along the outer diameter side, an outer diameter side end face located farther from the rotor and on the outer diameter side than the inner diameter side end face, and outside the outer diameter side end face. It has an outer diameter side surface covering the diameter side and a step surface disposed between the inner diameter side end surface and the outer diameter side end surface, and a first opening is formed in the step surface. By providing a step surface on the rear cover and forming an opening in the step surface, the amount of cooling air sucked into the AC generator for a vehicle can be increased.
[0009]
In addition, a second opening is formed in each of the inner diameter side end surface and the outer diameter side end surface described above, and the third opening is located on the outer diameter side surface, which is in the ground direction when attached to the vehicle. It is desirable that the part is formed. By forming the third opening on the outer diameter side surface together with the second opening formed on the inner diameter side end surface and the outer diameter side end surface, the amount of cooling air sucked into the vehicle alternator is further increased. It becomes possible to increase. In addition, by forming the third opening at a position in the ground direction on the outer diameter side surface, it is possible to discharge water that has once entered the interior of the rear cover from the first opening or the second opening. Thus, it is possible to prevent the occurrence of insulation failure in the rectifier caused by the ingress of water.
[0010]
The first and third openings described above are preferably arranged on the rear side of the rectifier along the rotation axis. As a result, the water that has entered the rear cover can be discharged from the first opening and the third opening before reaching the rectifier, further preventing the occurrence of insulation failure in the rectifier. It becomes possible.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
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. FIG. 2 is a partial cross-sectional view of the vehicle alternator shown in FIG.
[0012]
The vehicle alternator 1 according to the present embodiment includes a stator 2, a rotor 3, frames 4, 5, a rectifier 6, a brush device 7, a voltage regulator 8, a rear cover 9, and the like.
The stator 2 includes a stator core 22, a three-phase stator winding 23, and an insulator 24 that electrically insulates between the stator core 22 and the stator winding 23.
[0013]
The rotor 3 has a structure in which a field winding 31 in which an insulated copper wire is wound in a cylindrical and concentric manner is sandwiched from both sides through a rotating shaft 33 by a pole core 32 having six claws. have. A cooling fan 35 for discharging the cooling air sucked from the front side in the axial direction and the radial direction is attached to the end face of the pole core 32 on the front side by welding or the like. Similarly, a cooling fan 36 for discharging the cooling air sucked from the rear side in the radial direction is attached to the end surface of the pole core 32 on the rear side by welding or the like. In addition, two slip rings 37 and 38 that are electrically connected to both ends of the field winding 31 are formed in the vicinity of the rear side end portion of the rotating shaft 33, and the slip rings 37 and 38 are interposed through these slip rings 37 and 38. Then, power is supplied from the brush device 7 to the field winding 31.
[0014]
The frames 4 and 5 accommodate the stator 2 and the rotor 3, and the rotor 3 is supported in a state of being rotatable around the rotation shaft 33, and on the outer peripheral side of the pole core 32 of the rotor 3. The stator 2 arranged via a predetermined gap is fixed. These frames 4, 5 have cooling air discharge windows 41, 51 at portions facing the stator windings 23 protruding from the axial end face of the stator core 22, and suction windows 42, 52 at the axial end face. have.
[0015]
The rectifier 6 is for rectifying the three-phase AC voltage generated by the three-phase stator winding 23 to obtain a DC current. The rectifying device 6 includes a negative-side heat radiating plate 62 disposed on the frame 5 side along the rotation axis direction, and a positive-side radiating plate disposed so as to partially overlap the negative-electrode side heat radiating plate 62 at a predetermined interval. 63, a terminal block 61 disposed between them, a plurality of (for example, four) negative-side rectifying elements 65 attached to the negative-side heat radiating plate 62, and a plurality of attached to the positive-side radiating plate 63 (For example, four) positive electrode side rectifying elements 66 are provided.
[0016]
The negative-side heat radiating plate 62 has an arc shape having an outer diameter substantially equal to the inner diameter of the rear cover 9, and negative-electrode-side rectifying elements 65 are attached and fixed by press-fitting at four locations separated from each other along the circumferential direction. Yes. The positive-side heat radiating plate 63 has an arc shape with a smaller outer diameter than the negative-electrode-side heat radiating plate 62, and the positive-side rectifying element 66 is attached by press-fitting at four locations separated from each other along the circumferential direction. It is fixed.
[0017]
The rear cover 9 is a protective member made of metal, and is attached so as to cover the rectifying device 6, the brush device 7 and the voltage regulator 8 attached to the outside of the frame 5, and protects these from foreign matter and external moisture. To do. Details of the rear cover 9 will be described later.
[0018]
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 (not shown) is transmitted to the pulley 20 via a belt or the like. In this state, by applying an excitation voltage from the outside to the field winding 31 of the rotor 3, each claw portion of the pole core 32 is excited, and a three-phase AC voltage can be generated in the stator winding 23. A predetermined direct current is taken out from the output terminal of the rectifier 6.
[0019]
Next, details of the rear cover 9 will be described. FIG. 3 is a plan view of the rear cover 9 as viewed from the rear side (the side opposite to the rectifying device 6). 4 is an enlarged sectional view taken along line IV-IV in FIG. FIG. 5 is an enlarged cross-sectional view taken along line VV in FIG.
As shown in FIGS. 3 to 5, the rear cover 9 includes a rear end surface 91, an inner diameter side end surface 92, an outer diameter side end surface 93, a step surface 94, and an outer diameter side surface 95. .
[0020]
The rear-side peeling portion end surface 91 covers the rear-side end surfaces of the rotating shaft 33 of the rotor 3, the brush device 7, and the voltage regulator 8. A plurality of openings 910 for introducing cooling air into a heat radiating plate (not shown) of the voltage regulator 8 at a portion corresponding to the voltage regulator 8 at a part of the rear end face 91 on the rear side. Is provided.
[0021]
The inner diameter side end surface 92 faces the inner diameter portion of the positive electrode side heat radiating plate 63 disposed on the rear side of the negative electrode side heat radiating plate 62 of the rectifier 6. The inner diameter side end face 92 is formed with openings 912 and 914 arranged in two rows along the rotation direction.
The outer diameter side end surface 93 faces the outer diameter portion of the positive electrode side heat sink 63. The outer diameter side end face 93 is arranged on the rear side (position farther from the frame 5) along the rotation axis direction than the inner diameter side end face 92. The outer diameter side end face 93 is formed with openings 916 and 918 in two rows along the rotation direction.
[0022]
As shown in FIG. 4, a step surface 94 is formed between the inner diameter side end surface 92 and the outer diameter side end surface 93 in a direction substantially perpendicular to these end surfaces. An opening 920 is formed in the step surface 94.
The outer diameter side surface 95 extends from the outer diameter side end portion of the outer diameter side end surface 93 to the outer diameter side end portion of the negative electrode side heat radiation plate 62 of the rectifier 6 and the outer peripheral portion of the rear side end portion of the frame 5. Covering. This outer diameter side surface 95 is a position where the rear end surface of the positive-side heat radiating plate 63 of the rectifier 6 is extended, and the ground direction (the direction of the ground) when the vehicle alternator 1 is mounted on the vehicle. An opening 922 is formed along the rotational direction at a position within a predetermined range corresponding to.
[0023]
In the vehicle alternator 1 of the present embodiment, when rain water or the like is applied from the upper side (the direction opposite to the ground) and the rear cover 9 is flooded, most of the water travels down along the surface of the outer diameter side end surface 93. It flows down (arrow A in FIG. 2). A part of the water flows into the inside of the rear cover 9 through the openings 916 and 918 provided in the outer diameter side end surface 93 (arrows B and C in FIG. 2), and is then provided on the outer diameter side surface 95. It is discharged to the outside of the rear cover 9 through the opening 922.
[0024]
Thus, by providing the rear cover 9 with the step surface 94 and forming the opening 920 in the step surface 94, the amount of cooling air sucked into the vehicle alternator 1 can be increased. In addition, the openings 912, 914, 916, and 918 are provided in the inner diameter side end face 92 and the outer diameter side end face 93 and the outer diameter side face 95 is provided with an opening 922, thereby sucking into the vehicle alternator 1. The cooling air volume can be further increased. Further, by forming the opening 922 at a position in the ground direction of the outer diameter side surface 95, the openings 912 and 914 of the inner diameter side end surface 92, the openings 916 and 918 of the outer diameter side end surface 93, or the step surface 94 are formed. Water that has once entered the interior of the rear cover 9 from the opening 920 can be discharged, and it is possible to prevent the occurrence of insulation failure in the rectifier 6 caused by the intrusion of water. In particular, since the opening 920 of the step surface 94 and the opening 922 of the outer diameter side surface 95 are arranged on the rear side of the rectifying device 6, before the water that has entered the rear cover 9 reaches the rectifying device 6, These openings 920 and 922 can be discharged, and it is possible to further prevent the occurrence of insulation failure in the rectifier 6.
[0025]
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 rectifier 6 in which the negative-side heat radiating plate 62 is arranged on the frame 5 side and the positive-side radiating plate 63 is arranged on the rear side thereof is used. A rectifier having a side heat radiating plate and a negative side heat radiating plate disposed on the rear side may be used.
[0026]
In the above-described embodiment, the metal rear cover 9 is used, but a resin rear cover may be used.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall configuration of an automotive alternator according to an embodiment.
FIG. 2 is a partial cross-sectional view of the vehicle AC generator shown in FIG.
FIG. 3 is a plan view of a single rear cover as seen from the rear side.
4 is an enlarged sectional view taken along line IV-IV in FIG. 3;
5 is an enlarged cross-sectional view taken along line VV in FIG. 3;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Vehicle alternator 2 Stator 3 Rotor 4, 5 Frame 6 Rectifier 7 Brush device 8 Voltage regulator 9 Rear cover 61 Terminal block 62 Negative side heat sink 63 Positive side heat sink 65 Negative side rectifier 66 Positive side rectifier Element 91 Rear side end face 92 Inner diameter side end face 93 Outer diameter side end face 94 Step surface 95 Outer diameter side face 910, 912, 914, 916, 918, 920, 922 Opening

Claims (2)

A rotor, a stator having a stator winding that induces an alternating voltage when the rotor is rotated, a frame that supports the rotor in a rotatable state, and is attached to the outside of the frame In a vehicle AC generator comprising a rectifier that rectifies an AC voltage induced in the stator winding, and a rear cover that covers the rectifier from the outside,
The rear cover has an inner diameter side end surface disposed at a position close to the rotor along the rotation axis, and an outer diameter side end surface disposed at a position farther from the rotor and on the outer diameter side than the inner diameter side end surface. And an outer diameter side surface that covers the outer diameter side than the outer diameter side end surface, and a step surface disposed between the inner diameter side end surface and the outer diameter side end surface,
A first opening is formed in the step surface ;
A second opening is formed in each of the inner diameter side end face and the outer diameter side end face,
An AC generator for a vehicle, wherein a third opening is formed at a position on the outer diameter side surface that becomes a ground direction when attached to the vehicle. In claim 1,
The vehicle alternator according to claim 1, wherein the first and third openings are arranged on the rear side of the rectifier along the rotation axis.

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