JPH104663A - Ac generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent breakage or deterioration of a magnet held between pawl parts. SOLUTION: A plurality of permanent magnets 41 are disposed respectively between a plurality of pawl parts 12 and 22, forming opposite poles of a rotor. These permanent magnets 41 are so magnetized as to prevent a leakage flux, passing directly between the pawls. The permanent magnets 41 are protected by a nonmagnetic ring. Particularly, the nonmagnetic ring is interposed between the permanent magnets 41 and the pawl parts 12 and 22 and thereby a stress which the permanent magnets 41 receive from the pawl parts 12 and 22 is relaxed, while transfer of heat from the pawl parts 12 and 22 to the permanent magnets 41 is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC generator equipped with a magnet, and is particularly suitable for an AC generator for a vehicle.

[0002]

2. Description of the Related Art In recent years, low noise and high output have been demanded as social needs for vehicle alternators. Here, as a technique for improving the output of the vehicle alternator, for example, a technology disclosed in Japanese Patent Application Laid-Open No. 61-85045, “Vehicle Alternator” is known.

[0003]

In the rotor of the automotive alternator disclosed in the above publication, an effective magnetic flux contributing to power generation is generated by a permanent magnet as an auxiliary magnet provided between the claw portions of a pole core serving as claw-shaped magnetic poles. In addition, the output can be improved, the physique can be reduced in size, and the like. However, in the related art, since the permanent magnet is held in direct contact with the pole core, the permanent magnet receives an external force from the pole core and is easily damaged. For example, in order to clamp a permanent magnet, stress will be applied to the permanent magnet, and since it is given at a contact portion with a hard pole core, stress concentration will occur, causing cracking of the permanent magnet There is a risk.

[0004] Further, the rotor becomes high temperature due to eddy current loss and the like. However, in the prior art in which the permanent magnet is brought into direct contact with the pole core, heat is directly transmitted to the permanent magnet, which may adversely affect the permanent magnet thermally. was there. Such mechanical external force or thermal deterioration causes deterioration of the magnetic properties of the magnet, resulting in deterioration of the power generation performance, and makes it difficult to maintain the power generation performance.

[0005] The present invention has been made to solve the problems of the prior art. The present invention provides an AC generator that can reliably exhibit required power generation performance by mechanically or thermally protecting the magnet in an AC generator using a magnet in combination, and can maintain the power generation performance. The purpose is to:

[0006]

The present invention employs the following means to achieve the above object. According to the first aspect of the present invention, in an AC generator that excites a rotor core with a field coil, a magnet that increases a magnetic flux that contributes to power generation is provided, and the magnet is applied between the magnet and the core. A technical means called an alternator characterized by interposing a buffer layer for reducing a mechanical external force is adopted.

According to the present invention, since the buffer layer for alleviating the mechanical external force is interposed between the magnet and the core, the magnet can be protected from the mechanical external force, and the magnet may be damaged, for example, cracked or damaged. It is possible to prevent chipping and further decrease in magnetic performance due to the chipping. As a result, required power generation performance can be exhibited, and the power generation performance can be maintained.

According to the present invention, in an AC generator in which a rotor core is excited by a field coil, a magnet for increasing magnetic flux contributing to power generation is provided, and the magnet is provided between the magnet and the core. A technical means called an alternator characterized by interposing a buffer layer for relaxing heat conduction to the magnet is adopted. According to the present invention, since the buffer layer that alleviates heat conduction is interposed between the magnet and the core, the magnet can be protected thermally, and damage to the magnet caused by heat, and furthermore, magnetic damage caused by the heat can be prevented. Of the target performance can be prevented. As a result, required power generation performance can be exhibited, and the power generation performance can be maintained.

In the invention according to claim 3, the buffer layer is
Technical means of including a non-magnetic material interposed between the magnet and the core is employed. According to the present invention, the buffer layer can be obtained without affecting the magnetic characteristics of the rotor of the AC generator. According to a fourth aspect of the present invention, the buffer layer employs a technical means in which the magnet includes a resin formed by insert molding.

According to the present invention, the buffer layer can be obtained by the resin obtained by insert molding the magnet. Claim 5
In the invention described above, a technical means is adopted in which the buffer layer includes a connecting member that connects the plurality of magnets provided on the rotor. According to the present invention, the buffer layer can be obtained by the connecting member that connects the plurality of magnets, and the handling of the plurality of magnets can be facilitated.

[0011] In the invention according to claim 6, the buffer layer comprises:
Further, a technical means of including a buffer member or an adhesive interposed between the connecting member and the magnet is employed. According to the present invention, the material of the connecting member can be selected from a wide range. For example, the magnet can be protected mechanically or thermally even if metal is adopted. According to a seventh aspect of the present invention, a technical means is adopted in which the magnet is separated from the core by the buffer layer.

According to the present invention, it is possible to prevent the magnet from being directly adversely affected mechanically or thermally by the core. In the invention according to claim 8, in an AC generator that excites a rotor core with a field coil, a magnet formed to be smaller than a gap between magnetic poles of the core that is excited by the field coil is attached to the core. Technical means of an alternating current generator characterized by being held in the gap between the magnetic poles by a fixed holding member is employed.

According to the present invention, the magnet can be securely held by the holding member, and the magnet can be held smaller than the gap between the magnetic poles that cannot be sandwiched between the magnetic poles. Such a small magnet can be held by the holding member directly in a large area without making strong contact with the magnetic pole. In particular, since the magnet and the magnetic pole surface can be arranged apart from the magnetic pole without being sandwiched between the magnetic poles, the magnet and the surface of the magnetic pole are wide, and there is a problem of a stress applied to the magnet from the magnetic pole due to strong contact, and a problem from the magnetic pole to the magnet Can be solved, and effects such as reduction of stress applied to the magnet from the magnetic pole and reduction of the temperature of the magnet can be obtained.

According to a ninth aspect of the present invention, in the AC generator in which the rotor core is excited by the field coil, the leakage magnetic flux path of the core excited by the field coil includes:
A technical means called an AC generator, wherein a magnet in a direction for preventing leakage magnetic flux is held apart from the core by a holding member fixed to the core, is adopted.

According to the present invention, the magnet can be securely held by the holding member and can be arranged away from the magnetic pole, so that the magnet is not directly in contact with the magnetic pole over a wide area and strongly. , Especially since it is not sandwiched between magnetic poles, the magnet and the magnetic pole surface are wide,
In addition, it is possible to solve the problem of stress applied to the magnet from the magnetic pole due to strong contact and the problem of heat transfer from the magnetic pole to the magnet, and obtain an effect of reducing the stress applied to the magnet from the magnetic pole and reducing the temperature of the magnet. be able to.

According to a tenth aspect of the present invention, there is adopted a technical means in which the rotor has a pole core combined with claws facing each other, and the magnet is arranged between the claws. You. According to the present invention, in a so-called Landel type rotor structure, it is possible to obtain an improvement in power generation performance due to an increase in effective magnetic flux and an effect of protecting a magnet.

According to the eleventh aspect of the present invention, the technical means that the magnet includes a permanent magnet is employed. According to the present invention, a generally fragile permanent magnet can be employed.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on some examples. First, a first embodiment will be described. FIG. 1 is a longitudinal sectional view showing a configuration of a rotor of an automotive alternator according to the present invention, and FIG. 2 is a view showing a state where a pair of pole cores, a non-magnetic ring and a permanent magnet are assembled. It is a perspective view. FIG. 3 is a partial perspective view showing a nonmagnetic ring in which permanent magnets are disposed on the inner surface,
FIG. 4 is a partial vertical sectional view taken along the line IV-IV of FIG.

The rotor 10 of the automotive alternator mainly includes pole cores 11 and 21 as iron cores, a non-magnetic ring 31, a permanent magnet 41 as an auxiliary magnet, and electromagnetic excitation means. Field coil 45 and shaft 4
6 and fans 48 and 49. The pole cores 11 and 21 are respectively formed with a plurality of claw portions 12 and 22 that are claw-shaped magnetic poles protruding in the axial direction on the outer peripheral side. The pole cores 11 and 21 are combined with the claw portions 12 and 22 facing each other so as to be alternately positioned in the circumferential direction. The field coils 45 are sandwiched in an internal space formed therein, and the knurls provided on the shaft 46 are provided. And are integrally assembled.

As shown in FIG. 4, the nonmagnetic ring 31 has a side surface 32 in contact with the side surfaces 13 and 23 of the pawl portions 12 and 22 of the pole cores 11 and 21 and a bottom portion 33 thereof. , 22 are formed so as to be in contact with the inner side surfaces 14, 24, and to fill the space between the opposing claw portions 12, 22 and have the same outer diameter surface as the outer diameter surface of the claw portions 12, 22. .

On the inner surface 35 of the outer peripheral portion 34 of the nonmagnetic ring 31, a permanent magnet 41 is provided with a field coil 45.
And a gap. The permanent magnet 41 is magnetized so as to prevent a leakage magnetic flux between the magnetic poles of the claw portions 12 and 22 of the pole cores 11 and 21. As described above, the permanent magnet 41 is arranged between the claw portions 12 and 22 as the magnetic poles excited by the field coil 45, that is, in the leakage flux path of the magnetic flux supplied by the field coil 45.

On the surface of the permanent magnet 41, a plate-shaped non-magnetic ring 31 is arranged.
A side surface portion 32 of the non-magnetic ring 31 is disposed between the non-magnetic ring 31 and the claw portions 12 and 22, and an outer peripheral portion 34 of the non-magnetic ring 31 is disposed radially outside of the permanent magnet 41. 41 covers the outer surface in the radial direction. In addition, the nonmagnetic ring 31 is arranged such that the bottom 33 is in contact with the inner side surfaces 14, 24 of the claws 12, 22.
It is fixed to. For this reason, the outer peripheral portion 34 of the nonmagnetic ring 31 is disposed between the claws 12 and 22 and covers the radially outer side of the gap between the claws 12 and 22. The permanent magnet 41 is arranged radially inside the outer peripheral portion 34. For this reason, the outer peripheral portion 34 protects the permanent magnet 41 by preventing the permanent magnet 41 from being exposed to the outside in the radial direction, and furthermore, even if the permanent magnet 41 is cracked, the fragments are directed outward in the radial direction. Prevents scattering.

Further, in this embodiment, the permanent magnet 41 is wrapped radially outward and circumferentially by the non-magnetic ring 31. When the permanent magnet 41 is assembled to the pole cores 11 and 21, the outer peripheral portion 34 of the non-magnetic ring 31 is provided. The movement of the permanent magnet 41 to the outside in the radial direction is regulated by this. Therefore,
The permanent magnet 41 is fixed to the pole cores 11 and 21 via the non-magnetic ring 31.

Next, the operation will be described. Field coil 4
5 is supplied to a stator (not shown) disposed close to the outer peripheral surfaces of the pole cores 11 and 21 through the pole cores 11 and 21. 22 also flows as leakage magnetic flux.

Here, the claw portions 1 of the pole cores 11 and 21
Since the permanent magnet 41 is provided between the second and the second 22, the leakage magnetic flux can be reduced, and a part of the leakage magnetic flux can be used as an effective magnetic flux. As a result, as shown in FIG. 5, the output current with respect to the rotation speed can be increased as compared with the case where the permanent magnet 41 is not disposed between the claw portions 12 and 22 of the pole cores 11 and 21.

As described above, the non-magnetic ring 3
1 is the side surface 1 of the pawl portions 12 and 22 of the pole cores 11 and 21
Fill the gaps between 3 and 23 and the outer peripheral portion 3
4 is formed so as to be the same as the outer diameter of the claw portions 12 and 22. Therefore, the rotor 10 of this vehicle alternator is
Are claw portions 12, 2 of the pole cores 11, 21 even if they rotate at a high speed.
No wind noise occurs because there is no centrifugal fan effect due to 2.

Further, a gap is provided between the non-magnetic ring 31 and the field coil 45 over the entire circumference, and the ventilation inside the pole cores 11 and 21 is not impaired. Does not adversely affect cooling. Further, since the nonmagnetic ring 31 covers the outside of the permanent magnet 41 in the radial direction, the permanent magnet 41 is protected from the outside in the radial direction. Further, since the non-magnetic ring 31 as a connecting member for connecting the plurality of permanent magnets 41 is disposed between the permanent magnet 41 and the claw portions 12 and 22, the permanent magnet 41 is separated from the claw portions 12 and 22. The permanent magnets 41 are separated from each other and are also protected from the claw portions 12 and 22.

In particular, the nonmagnetic ring 31 includes
2 to form a buffer layer for alleviating the mechanical stress applied to the permanent magnet 41, and also form a buffer layer for mitigating the heat transfer from the claws 12, 22 to the permanent magnet 41.
It functions as a buffer member. Thus, the permanent magnet 41
Is protected by the non-magnetic ring 31, and the non-magnetic ring 31 functions as a plate-shaped protection member.

Further, the nonmagnetic ring 31 is fixed to the pole cores 11 and 21 and holds a plurality of permanent magnets 41.
It also functions as a holding member for fixing. The permanent magnet 41 having a size smaller than the gap between the claw portions 12 and 22 as the magnetic poles is held and fixed by the nonmagnetic ring 31 as the holding member.
The permanent magnets 41 are arranged away from the claws 12 and 22 without directly contacting the permanent magnets 2 and 22, and the permanent magnet 41 is protected from mechanical stress and thermal heat conduction.

Further, by using a plastic magnet for the permanent magnet 41, peeling and breakage of the magnet during and after assembly can be prevented. FIG.
FIG. 7 is a partial perspective view showing a second embodiment of the nonmagnetic ring and the like according to the present invention, and FIG. 7 is a partial longitudinal sectional view corresponding to FIG. 4 using the nonmagnetic ring of FIG. The components having the same functions as those of the above-described embodiment will be described with the same reference numerals.

The non-magnetic ring 31 is formed of resin, and the permanent magnet 41 is insert-molded. That is, in this embodiment, all surfaces of the permanent magnet 41 are covered and protected by the nonmagnetic ring 31. here,
The pole cores 11 and 2 are attached to the outer peripheral portion 34 of the nonmagnetic ring 31.
When there is a portion larger than the outer diameter surface of the claw portions 12 and 22, the portion is cut or the like to minimize irregularities, and the outer diameter surface of the claw portions 12 and 22 is made substantially the same as the outer diameter surface. Thereby, the effect of reducing wind noise can be increased.

FIG. 8 is a partial vertical sectional view showing a third embodiment of the nonmagnetic ring and the like according to the present invention. When the non-magnetic ring 31 is formed of a non-magnetic metal body and the permanent magnet 41 is formed of a metal magnet, the outer peripheral surface of the permanent magnet 41 disposed on the inner surface 35 side of the non-magnetic ring 31 By integrally forming at least a part of the contact surface with the non-magnetic ring 31 with the buffer member 42 or an adhesive interposed therebetween, the interference between the non-magnetic ring 31 and the permanent magnet 41 is eliminated, and An effect similar to that of the embodiment can be obtained. Thus, the effect of protecting the magnet can be improved by interposing a buffer member or an adhesive in addition to the non-magnetic ring 31.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a configuration of a rotor of an automotive alternator according to a specific embodiment of the present invention.

FIG. 2 is a partial perspective view showing a state where a pair of pole cores, a nonmagnetic ring, and a permanent magnet are assembled.

FIG. 3 is a partial perspective view showing a nonmagnetic ring in which a permanent magnet is provided on an inner surface.

FIG. 4 is a partial longitudinal sectional view taken along the line IV-IV in FIG. 2;

FIG. 5 is an explanatory diagram showing a relationship between a rotation speed and an output current depending on the presence or absence of a permanent magnet.

FIG. 6 shows a second example of the nonmagnetic ring or the like according to the present invention.
FIG. 3 is a partial perspective view showing the embodiment of FIG.

FIG. 7 is a partial longitudinal sectional view corresponding to FIG. 4 using the nonmagnetic ring of FIG. 6;

FIG. 8 is a third view of a non-magnetic ring or the like according to the present invention;
FIG. 4 is a partial longitudinal sectional view showing the example of FIG.

[Explanation of symbols]

 Reference Signs List 10 Rotor of vehicle alternator 11, 21 Pole core 12, 22 Claw (magnetic pole) 31 Nonmagnetic ring 41 Permanent magnet 45 Field coil 46 Shaft 48, 49 Fan

Claims (11)

[Claims] 1. An alternating current generator that excites a rotor core by a field coil, comprising: a magnet for increasing a magnetic flux contributing to power generation; and a mechanical force applied to the magnet between the magnet and the core. An alternator characterized by interposing a buffer layer for reducing external force. 2. An AC generator for exciting a rotor core with a field coil, comprising a magnet for increasing a magnetic flux contributing to power generation, wherein a heat transfer to the magnet is provided between the magnet and the core. An alternator characterized by having a buffer layer for relaxation. 3. The alternator according to claim 1, wherein the buffer layer includes a non-magnetic material interposed between the magnet and the core. 4. The alternator according to claim 1, wherein the buffer layer includes a resin in which the magnet is insert-molded. 5. The alternator according to claim 1, wherein the buffer layer includes a connecting member that connects the plurality of magnets provided on the rotor. 6. The alternator according to claim 5, wherein the buffer layer further includes a buffer member or an adhesive interposed between the connecting member and the magnet. 7. The alternator according to claim 1, wherein the magnet is separated from the core by the buffer layer. 8. An AC generator for exciting a rotor core by a field coil, wherein a magnet formed to be smaller than a gap between magnetic poles of the core excited by the field coil is fixed to the core. An alternator, wherein the generator is separated from the magnetic poles by a holding member and held in a gap between the magnetic poles. 9. An AC generator that excites a rotor core with a field coil, wherein a magnet in a leakage flux path of the core that is excited by the field coil is provided with a magnet in a direction that prevents leakage flux. An alternator characterized by being held apart from the core by a fixed holding member. 10. The rotor according to claim 1, wherein the rotor has a pole core combined with claws facing each other, and the magnet is arranged between the claws. The alternator as described. 11. The alternator according to claim 1, wherein the magnet includes a permanent magnet.