JP2702154B2 - Brushless alternator rotor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC generator used for, for example, an automobile, a small boat, and the like, and more particularly, to a rotor used for a Rundel type brushless AC generator. .

[Conventional technology]

2. Description of the Related Art In recent years, an AC generator (alternator) used for a car or the like has been increasingly required to have a small size and a high output due to a high-grade car and a high-density mounting in an engine room. In addition, there is also a demand for long life including quality improvement and maintenance-free.

Among them, the small and high output of the AC generator has been achieved by the conventional winding technology of the stator coil (improvement of the space factor in the coil frame).
And improved coil cooling technology. But,
Today, it is geometrically difficult to further increase the space factor of the stator coil. Effective means of doing so are disappearing.
Further, regarding the prolongation of the service life, the wear life of the brush, which is the sliding portion, becomes a problem.

In response to the above requirements, alternators in the future are shifting to high-speed rotating brushless alternators.

This type of brushless alternator is disclosed in
And a pair of rotor cores having a plurality of claw-shaped magnetic poles arranged in a circumferential direction, one of the rotor cores being fixed to a rotor shaft, and the other being one of the rotor cores. The field coil is fixedly arranged in a non-rotating state while being interposed between the claw-shaped magnetic pole and the outer periphery of the center of the rotor core.

Since the field coil is non-rotating, brushless operation is possible, but in order to further increase the speed of this type of brushless alternator, the following points must be improved. Was.

[Problems to be solved by the invention]

That is, in the conventional brushless AC generator, a non-magnetic ring is fixed to the center of the inner peripheral surface of the claw-shaped magnetic poles meshing with each other by welding, and the claw-shaped magnetic poles of the pair of rotor cores are connected to each other. According to the simple structure, since the tip of the claw-shaped magnetic pole of each rotor core is not restrained, high-speed rotation (20,0
(00 rpm or more), the tip of the claw-shaped magnetic pole spreads due to the centrifugal force of its own weight. As a result, a situation occurs in which the claw-shaped magnetic pole comes into contact with the stator core fixed and arranged on the outer peripheral side of the rotor core while maintaining a small gap, thereby causing a spark. In the worst case, the alternator is damaged.

Conventionally, it is necessary to weld the non-magnetic ring and all the claw-shaped magnetic poles from the radial direction, and there is a point to be improved in terms of workability.

Other couplings between claw-shaped magnetic poles are described in
In addition to filling the gap between the claw-shaped magnetic poles with the adhesive as described in Japanese Patent Publication No. 3 (Kokai) No. 3, a technique for filling the claw-shaped magnetic poles with adhesive other than the portion facing the stator core (both outer diameter ends of the claw-shaped magnetic poles) As described in Japanese Utility Model Publication No. 50-25283, hollow discs are applied to both ends in the axial direction of the claw-shaped magnetic pole, and the hollow disc is connected to the claw-shaped magnetic pole through a plurality of holes provided in the hollow disc. A technique of caulking and screwing to both end faces has been proposed.

However, in the adhesive bonding method, the strength of the adhesive is reduced by repeated cooling and heating for the adhesive, and it is not possible to meet the demand for strict high-speed resistance as in recent years. In the caulking and screw fixing method using a hollow disk, the coupling between the claw-shaped magnetic poles can be strengthened, but the leakage magnetic flux from the part of the claw-shaped magnetic pole that does not face the stator core to the side of the stator core increases, resulting in loss of output performance. In addition to the above, the hollow disk causes an increase in rotor weight.

The present invention has been made in view of the above points, and its object is to provide high-speed resistance, to simplify the assembly, to suppress the leakage magnetic flux,
An object of the present invention is to provide a high-output brushless alternator capable of suppressing weight.

[Means for solving the problem]

The present invention has a pair of rotor cores in which a plurality of claw-shaped magnetic poles are arranged in a circumferential direction, the claw-shaped magnetic poles of these rotor cores mesh with each other with a gap therebetween, and one of the rotor cores is provided. In a rotor of a brushless AC generator in which a rotor core is fixed to a rotor shaft and the other rotor core is coupled to a claw-shaped magnetic pole of the one rotor core via non-magnetic coupling means, each claw of the pair of rotor cores The non-stator core-facing portion, which is located on the outer diameter portion of the shaped magnetic pole and on both sides of the portion facing the stator core, has a smaller diameter than the stator core-facing portion, and a non-magnetic metal ring is press-fitted into the non-stator core facing portion. And the rotor cores are connected to each other.

[Action]

According to the above configuration, the outer diameter portion at each tip end of the claw-shaped magnetic poles of the pair of rotor cores is restrained by the nonmagnetic metal ring press-fitted to the outer diameter portion.

As a result, even when a strong centrifugal force acts on the claw-shaped magnetic pole by rotating the rotor at a high speed, the presence of this non-magnetic ring prevents the claw-shaped magnetic pole from spreading outward.

Also, since the portion of the claw-shaped magnetic pole into which the non-magnetic ring is fitted (the portion facing the non-stator core) is smaller in diameter than the outer diameter portion facing the stator core, the distance from the portion facing the non-stator core to the stator core is increased. In addition to suppressing the magnetic flux leakage from the non-stator core-facing portion to the side of the stator core, the non-magnetic ring is press-fitted to a smaller diameter than the outer diameter portion facing the stator core as described above. Even if a ring is attached, the weight of the rotor can be reduced.

Further, since the non-magnetic metal ring is attached to the claw-shaped magnetic pole by press-fitting, troublesome attaching work such as welding is not required, and the assembling work can be simplified.

〔Example〕

 An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention, and FIG. 2 is an exploded perspective view of a rotor core of the present embodiment. The brushless alternator according to the present embodiment is for a motor vehicle.

In the figure, reference numerals 1a and 1b denote a pair of brackets, and brackets 1a and 1b.
A stator core 3 with a stator coil 2 is sandwiched and fixed therebetween.

Reference numeral 4 denotes a rotor which is a main part of the present embodiment, and includes a rotor shaft 5, a pair of rotor cores 6, 7 and two non-magnetic rings 8, 9, and the like.

The rotor shaft 5 is supported by bearings 10 and 11 disposed inside the brackets 1a and 1b, and a pulley 12 for transmitting rotational power is attached to one end thereof. Also, a pair of rotor cores 6,
7 has a plurality of claw-shaped magnetic poles 6a, 7a arranged in the outer peripheral direction. The rotor core 6 has a cylindrical iron core 6b at the center, and a claw-shaped magnetic pole 6a is provided at one end of the cylindrical iron 6b. on the other hand,
As shown in FIG. 2, the rotor core 7 has a claw-shaped magnetic pole 7a disposed at one end of an annular body 7b. In each of the rotor cores 6 and 7, the respective claw-shaped magnetic poles 6a and 7a mesh with each other while maintaining a small gap G therebetween. Among them, the rotor core 6 is press-fitted and fixed to the rotor shaft 5, while the rotor core 7 is The rotor core 6 is coupled and fixed to the claw-shaped magnetic pole 6a via the non-magnetic rings 8,9.

In other words, the coupling between the pair of rotor cores 6 and 7 is such that the non-stator core facing portions located on the outer diameter portions of the claw-shaped magnetic poles 6a and 7a and on both sides of the portion facing the stator core 3 have a smaller diameter than the stator core facing portion. This is performed by press-fitting non-magnetic metal rings 8 and 9 into the non-stator core facing portion.

Here, the details of the connection between the rotor core 6 and the rotor core 7 will be described with reference to FIG.

As shown in FIG. 2, the outer diameter portion on the tip side (hereinafter referred to as the outer periphery of the tip portion) of the claw-shaped magnetic pole 6a of the rotor core 6 and the claw-shaped magnetic pole 7a of the rotor core 7 and the outer diameter portion on the root side (hereinafter, the root). Notches 13, 14 and 15, 16 for ring fitting are formed in the outer periphery. Due to the presence of such a notch, the non-stator core-facing portions located on the outer diameter portions of the claw-shaped magnetic poles 6a and 7a and on both sides of the portion facing the stator core 3 have a smaller diameter than the stator core-facing portion. Then, while engaging the claw-shaped magnetic poles of the pair of rotor cores 6 and 7, the non-magnetic ring 8 is axially pressed into the notch 14 on the outer periphery of the base of the claw-shaped magnetic pole 6a and the notch 15 on the outer periphery of the tip of the claw-shaped magnetic pole 7a. Fixed, meanwhile, claw-shaped magnetic pole
The non-magnetic ring 9 is press-fitted from the axial direction into the notch 13 on the outer periphery of the tip of 6a and the notch 16 on the outer periphery of the base of the claw-shaped magnetic pole 7a. In this way, as shown in FIG. 1, the nonmagnetic rings 8 and 9 are fitted and fixed to both ends of the outer peripheral portions of the claw-shaped magnetic poles 6a and 7a, and the claw-shaped magnetic poles 6a and , 7a are combined. The non-magnetic rings 8, 9 are made of SUS or aluminum.

When the rotor 4 is assembled in the brackets 1a, 1b, the claw-shaped magnetic poles 6a, 7a and the stator core 3 face each other via a minute gap. The pair of rotor cores 6 and 7 are configured to be cantilevered by the rotor shaft 5, and one end of the rotor core 7 is opened. Through this opening, a yoke 18 with a field coil 17 is provided inside the claw-shaped magnetic poles 6a and 7a. It will be decorated in. The yoke 18 is fixed to the bracket 1b with screws 19. By fixing the field coil 17 in a non-rotating state, brushless becomes possible. Claw type magnetic pole
Numerals 6a and 7a are N poles and S poles when the field coil 17 is excited, and N poles and S poles are alternately arranged by meshing with each other to form a rotating field pole.

On the outer wall of the bracket 1b, a diode 20 for full-wave rectification of the three-phase alternating current generated in the stator coil 2 and a regulator 21 for controlling the output voltage to be constant are fixedly arranged. 22,23
Is a cooling fan attached to the back of the rotor cores 6,7.

In the vehicle alternator having such a configuration, the rotational force from the engine is input through the pulley 5, and the rotor cores 6 and 7 rotate integrally with the rotor shaft 5. And
In the present embodiment, each claw-shaped magnetic pole 6a,
Since the outer periphery of the tip of 7a is constrained, even if a strong centrifugal force acts on the claw-shaped magnetic poles 6a, 7a during high-speed rotation, the claw-shaped magnetic poles 6a, 7a do not spread outward, preventing contact with the stator core 3. In addition, it is possible to provide a brushless AC generator having excellent high-speed rotation.

In addition, the coupling between the claw-shaped magnetic poles 6a, 7a is only required to press-fit the non-magnetic rings 8, 9 from the axial direction to both ends of the claw-shaped magnetic pole outer periphery, and the conventional method of welding the non-magnetic ring from the radial direction. The non-magnetic ring can be attached by a very simple method as compared with the above, and the assembling workability of this kind of generator can be improved.

Further, as another effect, since the nonmagnetic rings 8, 9 suppress the rotational runout of the claw-shaped magnetic poles 6a, 7a of the rotor cores 6, 7, so-called magnetic noise can be reduced. Also, 1
By providing the pair of non-magnetic rings 8 and 9 at both ends of the outer peripheral portions of the claw-shaped magnetic poles 6a and 7a, it is possible to contribute to an increase in output as follows.

First, the magnetic flux (arrow A in FIG. 1) which has leaked from the base of the claw-shaped magnetic pole to the side surface of the stator core 3 in the outside diameter portion of the non-magnetic ring press-fitting portion is cut out 13-16 to the outside diameter facing the stator core. Claw-shaped magnetic pole
The effective magnetic flux flowing from 6a, 7a to the inner peripheral side of the stator core 3 can be increased. Secondly, the adoption of the non-magnetic rings 8 and 9 can solve the problem of the spread of the claw-shaped magnetic poles 6a and 7a and the magnetic noise during high-speed rotation, so that the angle α of the claw-shaped magnetic pole can be made large as shown in FIG. In other words, if the angle α is increased, the magnetic pole area can be increased, so that the claw-shaped magnetic pole 6 having the maximum magnetic resistance is obtained.
The magnetic path area of the gap between the a and 7a and the inner circumference of the stator core 3 can also be increased. As a result, the magnetic flux density at the gap can be reduced, and the magnetic resistance can be reduced. Therefore, in addition to the high rotation of the alternator, the output of the brushless alternator can be increased by increasing the effective magnetic flux and decreasing the magnetic resistance.

〔The invention's effect〕

As described above, according to the present invention, it is possible to provide a high-output brushless AC generator that is excellent in high-speed resistance and that can simplify assembly, suppress leakage magnetic flux, and reduce weight.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention, and FIG. 2 is an exploded perspective view of a pair of rotor cores used in the above embodiment. 4 ... rotor, 5 ... rotor shaft, 6, 7 ... rotor core, 6
a, 7a ... claw-shaped magnetic pole, 8,9 ... non-magnetic ring, G ... gap.

Claims (1)

(57) [Claims] 1. A rotor core having a plurality of claw-shaped magnetic poles arranged in a circumferential direction, the claw-shaped magnetic poles of the rotor cores meshing with each other with a gap therebetween, and one of the rotor cores is provided. A rotor core is fixed to a rotor shaft, and the other rotor core is coupled to the claw-shaped magnetic poles of the one rotor core via non-magnetic coupling means, wherein each of the pair of rotor cores Non-stator core facing portions located on both sides of the outer diameter portion of the claw-shaped magnetic pole and the portion facing the stator core are made smaller than the diameter of the stator core facing portion, and a non-magnetic metal ring is pressed into the non-stator core facing portion. A rotor for a brushless alternator, wherein the rotor cores are fitted and connected to each other.