JPH04117154A - Ac generator for vehicle - Google Patents

Abstract

PURPOSE:To ensure effective amount of flux in a magnetic path formed between a rotor and a stator and to achieve a sufficient output performance as a vehicle by a constitution wherein the winding space of a bobbin applied with a field coil is enlarged from the inner diameter part toward the outer diameter part. CONSTITUTION:A rotor 14 is provided with a ring type space 15 formed coaxially with a rotary shaft 11, and a bobbin 17 applied with a field coil 16 is arranged in the space 15. One side face of a winding space 171 of the field coil 16 formed in the bobbin 17 is inclined by an angle theta so that the space 171 is enlarged from the inner diameter part toward the outer diameter part. Opposing face of an air gap 20 between the claw part 141 of the rotor 14 and the outer peripheral surface of the bobbin 17 is set substantially equal to the opposing face of an air gap 21 between the boss part 142 of the rotor 14 and the inner peripheral surface of the bobbin 17. Consequently, number of winding of a field coil 16 is increased from the inner peripheral part toward the outer peripheral part.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a brushless vehicular alternator installed, for example, in a passenger car.

[Prior Art] For example, as an alternating current generator mounted on a vehicle such as a passenger car, a structure in which an excitation current is supplied to a field coil through a brush is generally used. However, as vehicles become more versatile, vehicle engine compartments become smaller, and the number of auxiliary equipment increases, the mounting position of the generator tends to be restricted. The generator may be submerged in water (muddy water). If the brush is exposed to water in this way, the brush will not hang properly and the slip ring with which the brush comes into contact will wear out, leading to an increase in the number of failures.

In consideration of these points, consideration has been given to installing brushless alternating current generators, which have been installed in large vehicles such as trucks, in passenger cars as well. However, in a passenger car, the space available for installing a generator is limited, and the passenger car engine that drives this generator can be used up to a high rotation range compared to engines installed in large vehicles. be done. As for the specifications of this generator, it is necessary to have the same size and output performance as the generators installed in current passenger cars.

However, for alternating current generators with brushes,
While the structure has an air gap only between the rotor and stator, in brushless AC generators, there is an air gap between the rotor and stator as well as between the field coil. The structure is such that an air gap is formed between each of both sides and the rotor, increasing the magnetic resistance of the magnetic path formed between the rotor and stator, and reducing the amount of effective magnetic flux. Therefore, it is difficult to secure the same output performance with the same size as an alternator with a brush structure.

[Problems to be Solved by the Invention] This invention was made in view of the above points, and even if the body is miniaturized, the effective magnetic flux of the magnetic path formed between the rotor and the stator The present invention aims to provide a brushless type vehicular alternator which is effective when installed in a passenger car, etc., and which has a sufficient amount of output and has sufficient output performance for a vehicle.

[Means for Solving the Problem] In the brushless vehicular alternator according to the present invention, the winding space of the bobbin on which the field coil is wound extends from the inner diameter portion toward the outer diameter portion. Therefore, it is configured to be enlarged.

[Function] In the vehicle alternator configured in this way, it is possible to easily increase the number of turns of the field coil, and the brushless structure reduces the decrease in output caused by the increased air gap. A complementary ampere turn can be secured.

In addition, since the bobbin on which this field coil is wound can have an area facing the rotor at its outer diameter portion equal to an area facing the rotor at its inner diameter portion, There is virtually no increase in magnetic resistance, sufficient output performance is ensured, and it can be easily applied to passenger cars and the like.

[Embodiments of the invention] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

Figure 1 shows the cross-sectional structure of a vehicle alternator with a brushless structure. The attachment can be set freely, and a pulley 13 is provided coaxially with this rotating shaft 11. The rotation of an automobile engine (not shown) is transmitted to this pulley 13 via a belt, and the rotating shaft 11 of this generator is rotationally driven by the engine. and,
This rotating shaft 11 has a rotor 1 made of magnetic material.
4 are integrally attached, and the rotor 14 is rotated as the rotating shaft 11 rotates.

The rotor 14 has a ring-shaped space 15 formed coaxially with the rotating shaft 11, and a bobbin 17 around which a field coil 16 is wound is set in this space 15. , this bobbin 17 is frame 1
2b.

A stator 18 is disposed on the outer periphery of the rotor 14, and the stator 18 is attached to the inner periphery of the frame 12 at a position surrounding the rotor 14. And rotor 1
4 and the stator 18 is an air gap 191.

192 is formed.

Here, the winding space 1-71 of the field coil 16 formed in the bobbin 17 is formed with one side surface inclined by an angle θ so that it expands from the inner diameter toward the outer diameter. , an air gap 2 formed between the claw portion 141 of the rotor 14 and the outer peripheral surface of the bobbin 17.
The opposing areas of the air gap 21 portion formed between the boss portion 142 of the rotor 14 and the inner circumferential surface of the bobbin 17 are approximately the same. and,
By supplying an excitation current to the field coil 16, the stator 18, bobbin 17,
And a magnetic path 22 is formed in the rotor 14.

That is, when the width of the air gap 20 is Ll, the distance Φ of this gap 20 from the center of rotation is Dl, the width of the air gap 21 is L2, and the distance Φ of this gap 21 from the center of rotation is D2, π・Dl・Ll−π・D2ΦL2.

By configuring in this way, the field coil 1
The number of turns of the field coil 16 is increased from the inner circumference to the outer circumference, and the number of turns of the field coil 16 is significantly increased compared to the case where the inclination angle θ is not set overall. Therefore, by making it brushless, it is possible to secure ampere turns (excitation current x number of turns of the field coil 16) to compensate for the decreased output due to the increase in the air gaps 20 and 21.

In addition, by setting the inclination angle θ to enlarge the winding space 171 of the bobbin 17, the opposing area of the air gap 20 at the outer circumference of the bobbin 17 is
Since the opposing area is equivalent to the opposing area of the gap 21 at the inner circumferential portion of , there is almost no increase in magnetic resistance. Therefore, by making the AC generator brushless, sufficient output characteristics can be ensured without increasing the size, and the alternator can have a long life and improved environmental resistance, and is particularly suitable for passenger cars.

In this embodiment, an angle θ is set in the winding space to expand the outer diameter direction, but as shown in FIG. You can do it like this. In this figure, the same components as those in FIG. 1 are given the same reference numerals, and the explanation thereof will be omitted.

[Effects of the Invention] As described above, according to the vehicle AC generator according to the present invention, sufficient output performance is ensured without increasing the size due to the brushless design, and it is also effective for passenger cars. It is said that it can be installed on. In this case, a brushless effect can be reliably obtained, and reliability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional configuration diagram showing an alternating current generator according to one embodiment of the present invention, and FIG. 2 is a cross-sectional configuration diagram showing another embodiment of the present invention. 11... Rotating shaft, 12a 512b... Frame,
14... Rotor, 16... Bobbin, 17... Field coil, 18... Stator, 20.21... Air gap, 22... Magnetic path. Figure 2

Claims (1)

[Scope of Claims] A rotor made of a magnetic material and attached to a rotating shaft rotatably supported by a bearing on a frame constituting a generator shell; a stator made of a magnetic material, which is opposed to the rotor through an air gap, and is configured to surround the rotor; A bobbin that is set to surround the shaft and has a gap formed between the inner and outer peripheral surfaces of the bobbin and the rotor, and a field that is wound around the bobbin and through which an excitation current is passed. A vehicular alternator comprising: a coil, wherein a winding space of the bobbin around which the field coil is wound is expanded toward the outer circumference.