JPH07298585A - Alternator for vehicle - Google Patents

Abstract

PURPOSE:To decrease the leakage magnetic flux of a alternator for a vehicle by using permanent magnet, to improve output power, to prevent the accumulation of the heat in a field coil caused by the arrangement of the permanent magnet, to improve the cooling of the permanent magnet and to improve the assembling and the centrifugal-force resisting strength of the permanent magnet. CONSTITUTION:The magnetic flux generated from a permanent magnet 3, arranged between Randall pawl-shaped magnetic poles 1 and the magnetic flux generated by the energization of a field coil 2 are synthesized. A ventilating space 9 for obtaining the heat dissipation effect for the field coil is formed between the permanent magnet 3 and the field coil 2. A second ventilating space 9' is formed between the outer surface of the permanent magnet 3 and the pawl-shaped magnetic pole 1. The respective permanent magnets 3 are linked circumferentially with linking members 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle alternator, and more particularly to a vehicle alternator having a claw-shaped magnetic pole as a field rotor.

[0002]

2. Description of the Related Art Conventionally, in a vehicle alternator using a Lundell-type claw-shaped magnetic pole as a field rotor, one means for improving the output of the generator is to use the claw-shaped magnetic poles between the claw-shaped magnetic pole side facing portions and the claw-shaped magnetic poles. Paying attention to the fact that there is a large amount of leakage magnetic flux with the field coil, filling this part with an adhesive containing a magnetic material such as iron powder, and magnetizing in the opposite direction to the leakage magnetic flux reduces the leakage magnetic flux. A technique for reducing the power and improving the output of the generator is proposed in, for example, Japanese Patent Laid-Open No. 54-116610.

[0003]

SUMMARY OF THE INVENTION In the above-mentioned prior art, there is a drawback that the pressure resistance is significantly deteriorated due to the adhesion of a conductive substance such as iron powder in the vicinity of the winding, and a large amount of adhesion is required to obtain a sufficient fixing force. Since it is necessary to mix the agents, it is difficult to obtain the minimum anti-magnetism characteristics that can oppose the fully energized winding electromagnet, and it is not easy to uniformly fill the adhesive.

Although the magnetic flux leaking between the claw-shaped magnetic poles is somewhat attenuated by the adhesive kneading magnetic material, the field coil is covered with the adhesive and heat is trapped, resulting in a large decrease in the exciting force. As a result, there is a problem that almost no improvement in output can be expected, and the magnetomotive force of the permanent magnet is also reduced by the heat, so that the ability to reduce leakage magnetic flux is reduced. Therefore, the present invention effectively reduces the leakage magnetic flux, combines the magnetic fluxes of the field coil and the permanent magnet to improve the output, and eliminates the heat of the field coil to improve the cooling performance. The purpose of the invention is to prevent the decrease of the exciting force of the field coil and the magnetomotive force of the permanent magnet due to the sawdust, and to further improve the assembling property of the permanent magnet between the claw-shaped magnetic poles and the centrifugal resistance strength. is there.

[0005]

In order to achieve the above object, the vehicular AC generator of the present invention is arranged on the inner peripheral side of an armature core around which an output coil is wound, and has a Randell claw shape. AC power generation for a vehicle including a magnetic pole and a rotor having a field coil wound around the outer circumference of a cylindrical portion provided around the rotary shaft so as to be surrounded by the magnetic pole on the inner circumference side of the magnetic pole. In the machine, a winding field magnetic circuit that magnetizes the claw-shaped magnetic pole by supplying an exciting current to the field coil, and a permanent magnet disposed between the adjacent claw-shaped magnetic poles causes the claw-shaped magnetic pole to move the claw-shaped magnetic pole. A permanent magnet magnetic circuit that magnetizes in the opposite polarity direction, and the permanent magnet and the field coil are arranged between the permanent magnet and the field coil disposed on the inner peripheral side of the permanent magnet. There is a ventilation space that is separated by a radial gap. Adopts a configuration having a connecting member connecting the permanent magnet at an outer peripheral portion of the ventilation space. The second ventilation space may be formed such that the outer peripheral surface of the permanent magnet is located inside the outer peripheral surface of the claw-shaped magnetic pole.

[0006]

When the exciting current is applied, the magnetic flux generated by the field coil and the magnetic flux of the permanent magnet are combined to improve the output of the armature coil. The ventilation space formed between the field coil and the permanent magnet eliminates the heat buildup of the field coil, suppresses the heat of the field coil from being transferred to the permanent magnet, and Improves heat dissipation. In particular, the cooling air passing through this ventilation space cools the permanent magnet while swirling, and the centrifugal force increases the wind speed toward the outer periphery of the permanent magnet, so that not only the heat transfer from the field coil to the permanent magnet is blocked. The permanent magnet is sufficiently cooled, and the deterioration of the magnet characteristics is almost eliminated. Moreover, since the connecting member holds the permanent magnets by connecting them, a plurality of permanent magnets can be assembled at the same time, and the centrifugal force resistance is increased.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. In the present invention, the basic configuration of the vehicle alternator is the same as that of the conventional generator, so the configuration characteristic of the present invention will be described below. First, FIG. 1 is a partial sectional view in the circumferential direction of a claw-shaped magnetic pole portion showing a configuration in which a permanent magnet, which is a prerequisite for a vehicle AC generator according to the present invention, is individually arranged between each claw-shaped magnetic pole, and FIG. 1 is a schematic top view seen from the direction of arrow A in FIG. 3, FIG. 3 is a partial vertical cross-sectional side view showing a rotor of the vehicle AC generator of FIG. 1, and FIG. It is a characteristic diagram. In these figures, substantially collar-shaped protrusions 5 are formed on both sides of the claw-shaped magnetic pole 1, and the outer diameter surface of the collar-shaped protrusion is flush with the outer diameter surface of the rotor. Has a permanent magnet engaging portion 5'on the inner diameter side of the portion 5,
The permanent magnet 3 is engaged and fixed to the engaging portion 5'and the claw-shaped magnetic pole side surface portion 4 with an adhesive. The permanent magnet 3 is provided so as not to project to the outer diameter side from the rotor outer diameter surface and to project to the inner diameter side from the claw-shaped magnetic pole inner diameter surface 1 ', and the claw-shaped magnetic pole tip in the axial direction as well. It is arranged without overhanging. As shown in FIG. 3, a ventilation space 9 having a predetermined gap in the radial direction is provided between the permanent magnet 3 and the field coil 2. When the permanent magnet 3 is provided, the ventilation space 9 is muffled. The heat is easily dissipated easily to cool the permanent magnet 3 and the field coil 2 sufficiently. In addition,
The field coil 2 is a cylindrical portion 10 provided around the rotating shaft 8.
It is wound around the outside of. Further, as shown in FIG. 1, a second ventilation space 9 extending in the rotational axis direction is provided by arranging the permanent magnet 3 in a stepwise manner so that the outer peripheral surface of the permanent magnet 3 is located inside the outer peripheral surface of the claw-shaped magnetic pole 1. ′ Is formed, and the permanent magnet is cooled well even on the outer peripheral side. Further, the permanent magnet 3 has anisotropy such that it has an easy axis of magnetization in the circumferential direction and a hard axis of magnetization in the radial direction with respect to the rotation axis, and has a strong magnetic directionality in the circumferential direction, as shown in FIG. As described above, the claw-shaped magnetic poles are alternately set to the north and south poles so that the same polarity as the magnetic pole property generated by the original winding appears. Further, the above-mentioned brim-shaped projection 5 with which the permanent magnet 3 is engaged and the permanent magnet 3 have a coarse dimensional accuracy that can be easily manufactured, and are bonded and fixed to each other with the adhesive 6. Further, regarding the magnetic force of the permanent magnet 3, when the exciting current of the field coil 2 is set to zero and only the permanent magnet is excited to obtain the maximum output at the maximum rotation speed of the generator, the normal load of the vehicle (during vehicle operation) The load is almost equal to the demand value of the load connected to the generator, and its exciting force is adjusted so as not to exceed it.

When the exciting current of the field coil 2 is zero and the exciting force of the rotor is only the exciting of the permanent magnet 3, most of the magnetic flux of the permanent magnet is inside the rotor by using the claw-shaped magnetic pole 1 as a short circuit. A small amount of magnetic flux that circulates and cannot circulate toward the armature iron core, thereby generating electricity. The generated output current characteristic at this time is as shown by the solid line in FIG. 4, and most of the vehicle regular load I _L can be covered by the output current I _M in the generator operating rotation range, so when the load is only the regular load. Exciting current may be small. Further, since the generator output by only the permanent magnet does not exceed the vehicle normal load demand value, the storage battery voltage also does not rise above the predetermined value that can be established by the excitation current control. A dedicated regulator capable of reversible excitation that weakens the residual magnetic flux due to the magnet becomes unnecessary. The characteristic of FIG. 4 is that the output voltage is 1
When the voltage is constant at 3.5 V, the dotted line shows the generator output current characteristic due to the addition of the magnetic flux from the field coil 2 and the magnetic flux from the permanent magnet 3. When the coil excitation is applied, the magnetic flux of the permanent magnet cannot circulate in the iron core, and is added to the magnetic flux of the rotor iron core toward the armature. That is, the magnetic fluxes of both the permanent magnet 3 and the winding field coil 2 are added to act on power generation, and the cooling performance of the permanent magnet 3 and the field coil 2 is not deteriorated, and a large output increase effect is recognized. . For example, FIG. 10 shows an example of a test in which an anisotropic ferrite magnet is interposed between the claw-shaped magnetic poles of a 100 A class vehicle alternator, and an output up effect of about 2 times is recognized at around 1500 rpm.

5 to 8 are circumferential partial longitudinal sectional views of the claw-shaped magnetic pole portions showing other shapes of the permanent magnet 3 of FIG. 1 or a top view of an essential part. In FIG. 5, the permanent magnet 3 is a claw. The permanent magnets 3 which are not arranged between the upper magnetic pole side surfaces are elastic magnets and are supported and fixed between the claw-shaped magnetic pole side surfaces by a reaction force due to a predetermined tightening margin and deformation amount. ing. Figure 6
FIG. 3 is a partial top view of the claw-shaped magnetic pole portion, in which the sizes of the permanent magnets 3 sandwiched and fixed between the side surfaces of the claw-shaped magnetic poles are made different between the side surfaces. These are performed by adjusting the exciting force of the permanent magnets 3 depending on the number of the permanent magnets 3 and the way of providing them.

In FIG. 7, the side surface of the claw-shaped magnetic pole is formed in a concave shape to form a brim-shaped projection 5. Further, FIG. 8 shows that θ> 0 ° so that the claw-shaped magnetic pole side surface portion 4 substantially forms the collar-shaped protrusion portion 5.
The anisotropic permanent magnet 3 is formed so as to have arcuate magnetic field forming anisotropy indicated by reference numeral 7. The anisotropic permanent magnet 3 may be made of resin.

Next, a part of the embodiment of the present invention different from the above-described presupposed structure will be described. Figure 9
(A), (b) is the fragmentary sectional view, and each permanent magnet 3 arrange | positioned between the side surfaces of the claw-shaped magnetic pole 1 is a belt-shaped connecting member 31.
Are connected in the circumferential direction of the rotor. Further, the connecting member 31 is arranged so as to abut on the radially inner side of each claw-shaped magnetic pole 1, and connects and holds each permanent magnet.

With this construction, even if a large centrifugal force is applied to each permanent magnet 3 due to the rotation of the rotor, the centrifugal force strength is increased by the holding action of the connecting member 31. Moreover, when assembling each permanent magnet between the claw-shaped magnetic poles, a plurality of permanent magnets can be assembled at the same time. Also in this embodiment, a ventilation space 9 is provided between the field coil 2 and the permanent magnet 3.
Are provided to effectively cool the permanent magnet 3.

[0013]

In the vehicular AC generator of the present invention configured as described above, the permanent magnets are arranged between the adjacent claw-shaped magnetic poles, whereby the leakage magnetic flux generated between the claw-shaped magnetic poles is effectively reduced. The power generation output can be improved, and since the permanent magnet is arranged apart from the field coil via the ventilation space, the field coil can be prevented from remaining warm. Further, it has an excellent effect that the cooling property of the permanent magnet can be improved, the excitation force of the field coil and the magnetomotive force of the permanent magnet can be prevented from lowering due to heat, and a stable power generation output can be obtained. In addition, by connecting the permanent magnets by the connecting member, it is possible to remarkably improve the assembling workability and improve the centrifugal resistance strength of the permanent magnets as compared with the case where the magnets are arranged one by one between the claws. Have the effect.

Further, by forming the second ventilation space on the outer circumference of the permanent magnet, the cooling performance of the permanent magnet can be further improved.

[Brief description of drawings]

FIG. 1 is a partial longitudinal cross-sectional view in the circumferential direction of a claw-shaped magnetic pole showing the configuration of a vehicle AC generator that is a premise of the present invention.

FIG. 2 is a schematic top view seen from the direction of arrow A in FIG.

3 is a partial cross-sectional side view of the vehicle AC generator shown in FIG.

4 is a characteristic diagram illustrating characteristics of the vehicle alternator shown in FIG. 1. FIG.

5 is a partial vertical cross-sectional view showing another permanent magnet of the vehicle AC generator shown in FIG. 1. FIG.

FIG. 6 is a top view of relevant parts showing still another permanent magnet of the vehicle AC generator shown in FIG. 1.

FIG. 7 is a longitudinal sectional view of a main part showing still another permanent magnet of the vehicle alternator in FIG. 1.

FIG. 8 is a longitudinal sectional view of a main part showing still another permanent magnet of the vehicle alternator in FIG. 1.

9A and 9B show an embodiment of a vehicle AC generator according to the present invention, in which FIG. 9A is a longitudinal sectional view of a main part, and FIG. 9B is a sectional side view.

FIG. 10 is a characteristic diagram showing an example of power generation characteristics of the vehicle AC generator shown in FIG.

[Explanation of symbols]

 1 Claw-shaped magnetic pole 2 Field coil 3 Permanent magnet 9 Ventilation space 9'Second ventilation space 10 Cylindrical part 31 Connecting member

Claims (1)

[Claims] 1. An output coil is arranged on the inner circumference side of an armature core around which the output coil is wound, and is surrounded by a Lundell-shaped claw-shaped magnetic pole and the magnetic pole on the inner circumference side of the magnetic pole. In a vehicular AC generator including a rotor having a field coil wound around the outer periphery of a provided cylindrical portion, a winding for magnetizing the claw-shaped magnetic pole by passing an exciting current through the field coil. A permanent magnet magnetic circuit for magnetizing the claw-shaped magnetic poles in a direction opposite to the winding field magnetic circuit by a permanent magnet arranged between the adjacent claw-shaped magnetic poles; A ventilation space that separates the inner circumferential surface of the permanent magnet from the outer circumferential surface of the field coil with a predetermined radial gap is provided between the field coil and the field coil disposed on the inner circumferential side. And the permanent magnets are formed on the outer peripheral portion of the ventilation space. Automotive alternator, characterized in that it comprises a connecting member connecting Te. 2. A second ventilation space is formed by arranging the permanent magnet so that an outer peripheral surface of the permanent magnet is located inward of the outer peripheral surface of the claw-shaped magnetic pole in the radial direction. The vehicle alternator according to claim 1.