JPH04289752A - Ac generator for vehicle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a structure around brushes of a vehicle alternator that supplies current to a field coil through brushes, and in particular, the present invention relates to a structure around the brushes of a vehicle alternator that supplies current to a field coil through the brushes, and in particular, the abrasion powder of the brushes is efficiently discharged to the outside of the slip ring cover. Regarding structure.

0002

[Prior Art] The structure around the brushes of a conventional vehicle alternator is as described in Utility Model Application No. 61-108069.
The space surrounded by the slip ring and the slip ring cover is usually almost sealed. A labyrinth seal is formed between the slightly recessed part of the outer circumference of the slip ring and the slip ring cover, and slipping occurs only when there is a breathing effect with air through the labyrinth part and with the outside of the slip ring cover. It is possible to create air circulation between the space inside the ring and the space outside the ring.

0003

[Problems to be Solved by the Invention] In the above-mentioned prior art, the brush abrasion powder generated when the brush slides on the slip ring passes through the labyrinth space formed by the recess on the outer periphery of the slip ring and the slip ring cover. , only when there is a breathing effect inside and outside the slip ring cover due to the rotation of the fan, it will be discharged to the outside of the slip ring cover. Normally, a vehicle is operated while repeatedly accelerating and decelerating, so the generator that rotates with the engine also repeats acceleration and deceleration. At this time, due to the pressure difference in the cooling air created by the rotation of the fan in the generator, a breathing action occurs between the inside and outside of the slip ring cover, and the abrasion powder of the brushes is discharged to the outside of the slip ring cover. However, when driving at a constant speed, the pressure difference of the cooling air is weak, so the wear powder of the brushes is not discharged outside the slip ring cover, but accumulates in the recess on the outer periphery of the slip ring and the labyrinth section surrounded by the slip ring cover. or build up inside the slip ring cover. If the above-mentioned phenomenon is repeated, the labyrinth section will eventually become blocked with brush abrasion powder, or the brush abrasion powder accumulated in the slip ring cover will come into contact with the pair of slip rings. When the labyrinth part is blocked, the sliding part of the brush and slip ring becomes sealed, the temperature of the sliding part rises rapidly, and the wear of the brush is significantly accelerated.
The design life cannot be achieved. On the other hand, if the pair of slip rings becomes electrically conductive with the brush abrasion powder, the generated voltage may become uncontrollable, or the regulator (voltage regulator) built into the generator may be damaged, and in either case, the vehicle may be damaged. Cause serious damage.

[0004] In order to solve the problems of the prior art described above, an object of the present invention is to provide a vehicle for use in which air is actively supplied to the sliding parts of the slip ring and the brush, and brush abrasion powder can be discharged to the outside of the slip ring cover. Our purpose is to provide alternating current generators.

[0005]

[Means for solving the problem] In order to achieve the above object, the shaft is made hollow, one end surface of the shaft is partially crushed, and a cylindrical portion with a diameter smaller than the inner diameter of the shaft is created by machining or the like on the crushed inner diameter surface. . A second shaft to which a slip ring is fixed is fixed to the cylindrical portion. With the above configuration, the inner diameter portion of the shaft and the brush sliding portion are spatially connected. On the other hand, one side of the end face of the slip ring cover provided on the outer circumference of the slip ring is sealed and the other side has a maze-like structure, so that the spaces inside and outside the slip ring cover are spatially connected.

[0006]

[Operation] Cooling air is introduced into the generator by the rotation of a pair of cooling fans fixed to both sides of the rotor core. At this time, the pressure of the cooling air generated by the rotation of the fan on the slip ring side creates negative pressure in the space surrounded by the slip ring and the slip ring cover. Since the inside of the slip ring cover becomes negative pressure, the air inside the slip ring cover tries to escape to the outside of the slip ring cover through the labyrinth section formed on one end surface of the slip ring cover. Conventionally, there is no air to be replenished, so the air inside the slip ring cover does not move, but with the above configuration, air flows in from the middle of the shaft, and the rotation of the fan constantly pushes the air inside the slip ring cover out of the slip ring cover. is discharged to. Riding this air flow, the brush abrasion powder generated by the sliding of the slip ring and brush is constantly discharged to the outside of the slip ring cover without stagnation.

[0007]

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. In FIG. 1, a pair of buckets 1 and 2 forming the outer shell of the generator are connected to a stator core 4 around which a stator coil 3 is wound.
It is fixed via a plurality of bolts (not shown). Cylindrical bearing boxes 11 and 21 that protrude inside the generator are formed near the centers of the end faces of both brackets 1 and 2, and bearings 6 and 7 are attached to these bearing boxes 11 and 21, respectively. A shaft 8 is rotatably supported by bearings 6 and 7.

A pair of rotor cores 91, each having an even number of claw-shaped magnetic poles, are provided with a small gap inside the stator core 4.
92 is fixed to the shaft 8 with the field coil 10 sandwiched therein. Resin fans 31 and 32 are coaxially fixed to both side surfaces of the rotor cores 91 and 92. A pulley 43 is fixed to the tip of the shaft 8, and the blades of the fan 31 on the side of the pulley 43 face the side surface of the bracket 1 with an appropriate gap between them.
The blade portion also faces the side surface of the other bracket 2 with an appropriate gap in between.

A slip ring 51 that protrudes from the bracket 2 and is smaller than the inner diameter of the bearing 7 is fixed on the same axis of the shaft 8. A brush 61 slides on a pair of rings 52 and 53, and a brush 61 slides on the inner diameter side of the rings 52 and 53. The other ends of the leads 54 and 55 electrically fixed to are electrically connected to the lead wire drawn out from the field coil 10. The leads 54 and 55 of the slip ring 51 are covered with resin and embedded in a recess 81 formed by partially pressing the hollow shaft 8. Since the recessed portion 81 of the hollow shaft 8 is formed by partially pressing, the inner diameter surface has a contour formed by the original inner diameter portion 82 before pressing and the deformed portion after pressing. The deformed part is machined to a diameter smaller than the original inner diameter 82, and the slip ring shaft 56 is mechanically fixed to the machined part. As described above, the space between the shaft hollow portion 83 and the outer shape side of the slip ring 51 is connected. A substantially cylindrical slip ring cover 65 is provided on the outer side of the slip ring 51 to protect the slip ring 51 from the outside.

A diode 40 for rectifying the alternating current output induced in the stator coil 3 and a regulator 42 for controlling the output voltage to a constant level are fixed to the rear end of the bracket 2.
A cover 46 is fixed to further protect them. The cover 46 and the rear end of the slip ring cover 65 form a labyrinth 85 so as to engage with each other in the circumferential direction, thereby protecting the slip ring 51 from the outside and pneumatically connecting the inside and outside of the slip ring cover 65. ing.

With the above configuration, the pulley 4 fixed to the tip of the shaft 8 is driven by an engine (not shown) or the like.
When the rotation is transmitted to the rotor cores 91 and 92, the rotation of the fans 31 and 32 provided on the side surfaces of the rotor cores 91 and 92 causes cooling air to be sucked in through the intake windows and flow along the fans 31 and 32.
After the stator coil 3 is cooled, it is discharged from the bracket discharge window. At this time, the inside of the slip ring cover 65 becomes negative pressure due to the rotation of the fan 32. Due to the force of this negative pressure, air flows in from the pulley 43 side of the shaft hollow part 83, and the shaft inner diameter 82 and slip ring shaft fitting part 8
4 into the slip ring cover 65, where the air flows into the slip ring cover 65 together with the abrasion powder of the brush 61 generated by the rotation of the slip ring 51.
It passes through the labyrinth section 85 formed by the rear end and the cover 46 and is smoothly discharged to the outside of the slip ring cover 65.

According to the above operation, as long as the fan 32 is rotating, the abrasion powder of the brush 61 generated by the rotation of the slip ring 51 does not stay inside the slip ring cover 65 and is smoothly discharged to the outside of the slip ring cover 65. effective. Furthermore, since the cooling air passes through the shaft hollow portion 83, cooling of the field coil 10 is also promoted. In other words, this leads to an increase in the output of the generator, making it possible to improve efficiency and further downsize the generator.

[0013]

According to the present invention, when the slip ring rotates and brush abrasion powder is generated, the fan is always rotating as well, so the slip ring cover is removed from the shaft hollow part due to the negative pressure generated by the rotation of the fan. The effect is that air flows in, entrains the brush abrasion powder, and smoothly discharges the brush abrasion powder to the outside of the slip ring cover through the labyrinth formed by the slip ring cover and the cover.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a vehicle alternator showing one embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a brush and its surroundings showing an embodiment of the present invention.

FIG. 3 is a sectional view taken along line CC in FIG. 2, showing an embodiment of the present invention.

[Explanation of symbols]

1, 2... Bracket, 6, 7... Bearing, 8... Shaft, 10... Field coil, 31, 32... Fan, 46... Cover, 51... Slip ring, 53... Slip ring cover, 61... Brush, 91, 92 ...rotor core.

Claims (1)

[Claims] 1. A shaft to which a pair of rotor cores, each having a field coil sandwiched therebetween and a fan arranged on each side thereof, is fixed, a slip ring coaxially fixed to an end surface of the shaft, and the shaft. a pair of bearings that rotatably support the bearings, a pair of brackets that enclose the bearings on the inner diameter side of their end faces, a pair of brushes that slide on the slip ring, and a substantially cylindrical shape that covers the outer circumferential side of the slip ring. In a vehicle alternator comprising a slip ring cover and a cover that covers the end face of the slip ring and the slip ring cover from the axial direction, the shaft is hollow and the hollow space, the slip ring and the slip ring cover are An alternator for a vehicle, characterized in that the space surrounded by the slip ring and the slip ring cover are connected to each other, and the space surrounded by the slip ring and the slip ring cover is spatially connected to the outer peripheral side of the slip ring cover. .