JP2003324916A - Ac generator for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable AC generator for a vehicle, which can achieve high output while suppressing the occurrence of eddy voltage. <P>SOLUTION: The magnetic clearance δ between a rotor 5 and a stator 6 is set to 0.55-0.65 mm, using a permanent magnet 17, 1.0 (T) or over in residual magnetic flux density. Consequently, even if the rotor 5 is rotated at high speed in case that the magnitude of stationary electric load connected is small, voltage more excessive than objective regulation voltage is not generated by the magnetic flux leaked from the permanent magnet 17, so excessive voltage more than specified is never applied to electric load or a battery mounted on the vehicle. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle AC generator for generating electric power for driving an electric load mounted on a vehicle and electric power for charging a storage battery.

[0002]

2. Description of the Related Art An alternator for a vehicle is provided with a rotor having a pair of Landel-type iron cores having a plurality of claw-shaped magnetic poles, and the rotor is rotated at a high speed to generate electric power. Recently, as the electric load on a vehicle increases, there is a strong market need for high-output AC generators for vehicles.

As a conventional vehicular AC generator for improving the power generation output, for example, one disclosed in Japanese Patent Laid-Open No. 61-85045 is known. In the vehicle alternator disclosed in this publication, a permanent magnet is arranged between the claw-shaped magnetic poles of the rotor to reduce the leakage magnetic flux between the claw-shaped magnetic poles and increase the effective magnetic flux that contributes to power generation. The output of the AC generator is improved.

[0004]

However, in the conventional vehicular AC generator, when the size of the steady-state electric load to be connected is small, when the rotor is rotated at high speed, the permanent magnets built in the rotor generate electric power. No consideration has been given to the fact that an excessive voltage higher than the target adjustment voltage is generated due to the leakage magnetic flux, and an excessive voltage exceeding a specified value is applied to an electric load or a battery mounted on the vehicle.

[0005]

SUMMARY OF THE INVENTION The present invention provides a highly reliable vehicle alternator capable of achieving high output while suppressing the occurrence of overvoltage.

For this reason, one representative example of the present invention has a polarity that reduces the leakage magnetic flux between the claw-shaped magnetic poles adjacent in the circumferential direction of the iron core between the claw-shaped magnetic poles adjacent in the circumferential direction of the iron core. With a residual magnetic flux density of 1.0 [T] or more, and a magnetic gap between the stator and the rotor arranged facing the rotor is 0.55 to 0.65 [. mm].

According to a typical one of the present invention having such a configuration, even if the rotor is rotated at a high speed when the connected steady use electric load is small, the leakage magnetic flux from the magnet is generated. Does not generate a voltage higher than the target adjustment voltage. Therefore, an excessive voltage exceeding the regulation is not applied to the electric load and the battery mounted on the vehicle.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows the overall configuration of the vehicle alternator of this embodiment. 2, FIG. 4 to FIG. 6 show the structure of the rotor of the vehicle alternator of this embodiment. 3 and 7 show
The structure of the permanent magnet holder used for the rotor of the vehicle AC generator of this embodiment is shown. FIG. 8 shows the structure of a permanent magnet used in the rotor of the vehicle AC generator of this embodiment.
FIG. 9 shows the relationship between the magnetic gap δ between the stator and the rotor, the non-excitation generated voltage, and the output current in the vehicle AC generator of this embodiment.

The vehicle alternator of this embodiment receives the field current and receives the rotational driving force of the engine, which is the internal combustion engine of the automobile, to rotate the rotor and generate AC power in the stator. Then, the generated AC power is rectified by a rectifier to obtain DC power (power for driving an electric load mounted on the vehicle and power for charging a storage battery). In the vehicle AC generator of this embodiment, the cooling water is circulated in the machine to cool the heating element such as the stator. It is a so-called water-cooled synchronous generator, and may be called an alternator or a vehicle charging generator. The cooling water is used for cooling the engine of the automobile and also for branching a part of the cooling water cooled by the radiator attached to the engine.

In the figure, 1 is a front bracket. 2 is a rear bracket. Front bracket 1
Is an aluminum annular member, and holds the bearing device on the inner peripheral side thereof. The rear bracket 2 is a container member made of aluminum, and includes a substantially cylindrical peripheral wall 2a and a side wall 2b that closes the side of the peripheral wall 2a opposite to the front bracket 1 side. Side wall 2b of rear bracket 2
Has a central portion projecting to the side opposite to the front bracket 1 side. A bearing device is held on the inner peripheral side of the tip of the protruding portion of the side wall 2b. Inside the peripheral wall 2a, a cooling water passage 2c for cooling water circulation, which is open at an end on the side of the front bracket 1
Are formed. Front bracket 1 is cooling water channel 2
The open end of c is blocked.

A stator 6 is held on the inner peripheral side of the peripheral wall 2a. The stator 6 has a stator core 19 and a stator coil 20. The stator core 19 is a cylindrical magnetic member and has a plurality of slots formed on the inner peripheral portion thereof. The stator coils 20 are inserted into the plurality of slots of the stator core 19. The stator coil 20 is u
The coils of the respective phases constituting the three phases of the v-phase, the v-phase, and the w-phase are inserted and connected in the corresponding slots, and the alternating-current power is generated by the change in the magnetic flux generated in the rotor coil 13 as the rotor 5 rotates. To occur.

On the inner peripheral side of the stator 6, a Lundell type rotor 5 is arranged to face the stator 6 with a magnetic gap.
Are rotatably arranged. A magnetic gap between the stator 6 and the rotor 5, specifically, the inner peripheral surface of the stator core 19 and the claw-shaped magnetic poles 14a and 15 of the pole cores 14 and 15.
The magnetic gap with the outer peripheral surface of a is set to 0.55 to 0.65 mm.

The rotor 5 has iron pole cores 14 and 15. A plurality of claw-shaped magnetic poles 14a are formed on the pole core 14 in the circumferential direction. The pole core 15 has a claw-shaped magnetic pole 15
A plurality of a are formed in the circumferential direction. Pole core 14,1
5 is fixed on the shaft 4 so as to face each other in the axial direction of the rotating shaft so that the claw-shaped magnetic poles 14a and the claw-shaped magnetic poles 15a are alternately arranged in the circumferential direction.

A rotor coil 13 wound around a bobbin and subjected to an insulation treatment is provided at a portion facing the inner peripheral surfaces of the claw-shaped magnetic poles 14a and 15a. A magnetic body 16 is mounted between the claw-shaped magnetic poles 14a and 15a adjacent to each other in the circumferential direction so as to cover the rotor coil 13. The magnetic body 16 is a resin molded body in which the entire circumference of the permanent magnet 17 is covered with resin, and is composed of a support portion 21 and a magnetic portion 23.

The support portion 21 is a cylindrical resin molding portion which has elasticity and can be displaced in the radial direction.
It has a step portion that comes into contact with a step portion formed on the back side of a, 15a. The magnetic part 23 is a resin molding part provided so as to meander on the circumference of the support part 21, and is composed of a rectangular permanent magnet 17 and a cover part 18 that covers the entire circumference of the permanent magnet 17, and the magnetic part 23 is arranged in the circumferential direction. Is mounted between the side surfaces of the claw-shaped magnetic poles 14a and 15a adjacent to each other. Here, “providing meandering on the circumference of the support part 21” means that the magnetic part is arranged on the circumference of the support part 21 so as to draw a path that goes in a zigzag manner on the circumference of the support part 21. It means that 23 is provided. From another point of view, it means that the magnetic portions 23 are provided on the circumference of the support portion 21 so that the adjacent magnetic portions 23 draw the letter “C” on the circumference of the support portion 21.

The permanent magnet 17 is made of cobalt, neodymium,
It is made of a rare earth material such as boron and has a residual magnetic flux density of 1.0 (T) or more. Further, the permanent magnet 17 includes the claw-shaped magnetic poles 14a, 15 having the magnetic portions 23 adjacent to each other.
When mounted between a, the N pole surface of the permanent magnet 17 faces the claw-shaped magnetic pole magnetized to the N pole, and the S pole surface of the permanent magnet 17 faces the claw-shaped magnetic pole magnetized to the S pole. That is, it is arranged so as to have a polarity that reduces the leakage magnetic flux between the claw-shaped magnetic poles 14a and 15a adjacent to each other in the circumferential direction. Cover 18
Is formed with a thickness λ between the claw-shaped magnetic poles 14a and 15a and the permanent magnet 17 which are adjacent to each other in the circumferential direction.

The magnetic body 16 is molded by injecting a polyamide resin into the mold with the permanent magnet 17 arranged in the mold. Thereby, the support portion 21 and the magnetic portion 2
3 is integrally molded.

The shaft 4 extends in the axial direction of the central axis of the peripheral wall 2a. One end of the shaft 4 is rotatably supported by a bearing device held by the front bracket 1. The other end of the shaft 4 is rotatably supported by a bearing device held by the side wall 2b. One end of the shaft 4 extends outside the front bracket 1. The pulley 3 is fixed to the tip of one end of the shaft 4. The pulley 3 is mechanically connected to a pulley provided on a crankshaft of an engine of an automobile through a chain or a belt which is a driving force transmission means, and receives a rotational driving force from the engine.

A slip ring 7 is fixed to the other end of the shaft 4 on the side opposite to the front bracket 1 side of the side wall 2b. The slip ring 7 is a conductive annular member, and is electrically connected to the rotor coil 13. A brush 8 is in sliding contact with the slip ring 7. A field current is supplied to the slip ring 7 via the brush 8. The brush 8 is held by a brush holder 9 fixed to the side wall 1b on the side opposite to the front bracket 1 side. A spring, which is an elastic body, is provided in the brush holder 9. The spring presses the brush 8 to bring the brush 8 into sliding contact with the slip ring 7.

A rectifier 10 that is electrically connected to the stator coil 20 and that rectifies the AC voltage generated in the stator coil 20 into a DC voltage is fixed to the side wall 1B opposite to the front bracket 1 side. A heat sink 11 is attached to the brush holder 9. The heat sink 11 is equipped with a regulator 12 that adjusts the magnitude of the AC voltage generated in the stator coil 20. The side of the side wall 1B opposite to the side of the front bracket 1 (the side to which the rectifier 10, the regulator 12 and the brush holder 9 are fixed) is covered with a cover 22.

In the vehicular AC generator configured as described above, current is supplied from the battery to the rotor coil 13 via the brush 8 and the slip ring 7. This allows
Magnetic flux is generated, and the claw-shaped magnetic pole 14a of the pole core 14 is magnetized to the N pole and the claw-shaped magnetic pole 15a of the pole core 15 is magnetized to the S pole. On the other hand, when the pulley 3 is driven by the engine which is the internal combustion engine of the automobile to rotate the shaft 4 and the rotor 5 rotates, a rotating magnetic field is applied to the stator coil 20. As a result, an alternating electromotive force is generated in the stator coil 20. The AC electromotive force is rectified into a direct current through the rectifier 10, and the magnitude thereof is adjusted by the regulator 12 to charge the battery. Alternatively, it is supplied to an electric load mounted on the automobile.

Next, a method of mounting the magnetic body 16 on the rotor 5 will be described. The magnetic body 16 is attached to the rotor 5 by
With the rotor coil 13 housed in the support portion of the rotor 5 in advance, the claw-shaped magnetic poles 14a from both sides in the axial direction of the central axis of the magnetic body 16 are sandwiched between the magnetic portions 23 that meander.
15a is pushed in. At this time, the covering portion 1 is provided between the permanent magnet 17 and the claw-shaped magnetic poles 14a and 15a that are adjacent to each other in the circumferential direction.
8 is formed with a thickness λ, the claw-shaped magnetic poles 14a, 1
When the 5a is pushed, the claw-shaped magnetic poles 14a and 15a do not collide with the permanent magnet 17 and the permanent magnet 17 is not damaged.

As the rotor 5 rotates, the claw-shaped magnetic pole 14
A centrifugal force acts on a, 15a and the permanent magnet 17. However, since the permanent magnet 17 is mainly supported by the cylindrical support portion 21, the load of centrifugal force is not applied to the permanent magnet 17, and the permanent magnet 17 can be prevented from being damaged by the centrifugal force.

When the rotor 5 is assembled, the cover 18 is pushed inward by the claw-shaped magnetic poles 14a and 15a, so that the support 21 is slightly displaced radially inward. However, when the rotor 5 rotates, the supporting portion 21 is displaced radially outward by the centrifugal force, so that the residual stress generated in the cover portion 18 when the rotor 5 is assembled is reduced.

Next, the relationship between the magnetic gap δ between the stator and the rotor, the non-excitation generated voltage, and the output current in the vehicle AC generator of this embodiment will be described. FIG. 9 shows a magnetic field between the rotor 5 and the stator 6 under the condition that the rotation speed of the rotor 5 is 5000 r / min using the permanent magnet 17 having a residual magnetic flux density of 1.0 (T) or more. FIG. 6 is a characteristic diagram when a non-excitation generated voltage and an output current (vertical axis) are actually measured with a gap δ (air gap) as a parameter (horizontal axis).

As can be seen from FIG. 9, δ = 0.55-0.
At 65 mm, a change point of the decrease gradient of the non-excitation generated voltage is found, and beyond this change point, the decrease of the non-excitation generated voltage decreases at an accelerating rate. Note that, although FIG. 9 shows the actual measurement data performed under the condition that the rotation speed of the rotor 5 is 5000 r / min, the inventors of the present application also performed actual measurement when the rotation speed was changed. As a result, the value of the non-excitation generated voltage only changed in proportion to the rotation speed, and the position of the inflection point was almost constant.

From the above, the inventors of the present application used the permanent magnet 17 having a residual magnetic flux density of 1.0 (T) or more, and used the magnetic gap δ (air gap) between the rotor 5 and the stator 6.
If the vehicle alternator is designed so that the distance is 0.55 to 0.65 mm, the value of the non-excitation generated voltage of the generator can be kept within an appropriate value range. With the increase in output, it has been found that an excessive voltage exceeding the regulation of the electric load and the battery mounted on the vehicle is not applied.

According to this embodiment described above, the permanent magnet 17 having a residual magnetic flux density of 1.0 (T) or more is used, and the rotor 5
And the magnetic gap δ between the stator 6 and the stator 6 is 0.55 to 0.65.
Since the value is set to mm, even if the rotor 5 is rotated at a high speed when the size of the connected steady-use electric load is small, the leakage magnetic flux from the permanent magnet 17 may cause an excessive voltage higher than the target adjustment voltage. In addition, an excessive voltage exceeding the regulation is not applied to the electric load and the battery mounted on the vehicle. Therefore, according to this embodiment, it is possible to provide a highly reliable vehicle alternator capable of achieving high output while suppressing the occurrence of overvoltage.

Further, according to the present embodiment, the magnetic portion 23 is formed by covering the entire circumference of the permanent magnet 17 with the cover portion 18,
Since it is provided so as to meander on the circumference of the support portion 21, the centrifugal force applied to the permanent magnet 17 can be supported by the entire magnetic body 16, and damage to the permanent magnet 17 due to the centrifugal force can be prevented.

Further, according to the present embodiment, the claw-shaped magnetic pole 14
Since a covering portion 18 having a thickness is formed between the a and 15a and the permanent magnet 17, it is permanent while the claw-shaped magnetic poles 14a and 15a are being incorporated from both sides in the axial direction of the central axis of the magnetic body 16. It is possible to prevent the permanent magnet 17 from being damaged by the claw-shaped magnetic poles 14a and 15a colliding with the magnet 17. Further, according to the assembling method as in this embodiment, high accuracy is not required in the circumferential dimension of the claw-shaped magnetic poles 14a and 15a, so that the claw-shaped magnetic poles 14a and 15a can be easily formed.

Further, according to the present embodiment, the claw-shaped magnetic pole 14
Since the cover portion 18 is supported by the cylindrical support portion 21 inside the a and 15a, the centrifugal force resistance strength of the magnetic body 16 can be significantly improved.

Further, according to this embodiment, since the support portion 21 has elasticity, the magnetic body 16 and the claw-shaped magnetic poles 14a, 15a are provided.
Even if there is a manufacturing dimensional error, the error is absorbed, and the claw-shaped magnetic poles 14a, 1 are inserted from both sides in the axial direction of the central axis of the magnetic body 16.
5a can be incorporated.

Further, according to this embodiment, since the magnetic portion 23 and the supporting portion 21 are integrally molded by insert molding, the magnetic portion 23 and the supporting portion 21 can be easily integrated.

Further, according to this embodiment, since the magnetic body 16 is made of a resin molded body of polyamide resin, it is possible to obtain the magnetic body 16 excellent in elasticity and insulating property at low cost.

[0035]

According to the present invention described above, an excessive voltage exceeding a specified value is not applied to an electric load or a battery mounted on a vehicle. Therefore, according to the present invention, it is possible to provide a highly reliable vehicle alternator capable of achieving high output while suppressing the occurrence of overvoltage.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the overall configuration of a vehicle AC generator that is an embodiment of the present invention.

FIG. 2 is a perspective view showing an external configuration of a rotor of the vehicle AC generator of FIG.

3 is a perspective view showing the configuration of a magnetic body mounted on the rotor of the vehicle alternator of FIG.

FIG. 4 is a cross-sectional view showing an internal configuration of a rotor of the vehicle AC generator of FIG.

5 is a partial cross-sectional view showing a partial configuration of a rotor of the vehicle alternator of FIG.

6 is a perspective view showing a configuration of a pole core of a rotor of the vehicle alternator of FIG.

7 is a front view showing the configuration of a magnetic body mounted on the rotor of the vehicle AC generator of FIG.

8 is a perspective view showing a configuration of a permanent magnet embedded in a magnetic body mounted on the rotor of the vehicle AC generator of FIG.

FIG. 9 is a characteristic diagram showing a relationship between a magnetic gap δ between a stator and a rotor, a non-excitation generated voltage, and an output current in the vehicle AC generator of this embodiment.

[Explanation of symbols]

1 ... Front bracket, 2 ... Rear bracket, 3 ... Pulley, 4 ... Shaft, 5 ... Rotor, 6 ... Stator, 7 ...
Slip ring, 8 ... Brush, 9 ... Brush holder, 10
… Rectifier, 11… Heat sink, 12… Regulator,
13 ... Rotor coil, 14, 15 ... Pole core, 16 ...
Magnetic material, 17 ... Permanent magnet, 18 ... Covering portion, 19 ... Stator core, 20 ... Stator coil, 21 ... Supporting portion, 22 ...
Cover, 23 ... Magnetic part.

Continued front page    (72) Inventor Yuichiro Baba             Hitachinaka City, Ibaraki Prefecture 2520 Takaba             Ceremony Company Hitachi Ltd. Automotive equipment group (72) Inventor Kazuo Horioka             Hitachinaka City, Ibaraki Prefecture 2520 Takaba             Ceremony Company Hitachi Ltd. Automotive equipment group (72) Inventor Yama-saki Shinji             Hitachinaka City, Ibaraki Prefecture 2520 Takaba             Ceremony Company Hitachi Ltd. Automotive equipment group (72) Shinji Kikawa             2477 Takaba, Hitachinaka City, Ibaraki Prefecture Stock Association             Inside Hitachi Car Engineering F-term (reference) 5H619 AA01 BB02 BB10 BB17 PP08                       PP13                 5H622 AA03 CA07 CB04 DD02 PP03                       PP20 QA08

Claims (6)

[Claims] 1. A pair of Lundell-type iron cores having a plurality of claw-shaped magnetic poles, and claw-shaped magnetic poles disposed between the claw-shaped magnetic poles adjacent to each other in the circumferential direction of the iron cores and adjacent to each other in the circumferential direction of the iron core. A rotor having a magnet having a polarity that reduces leakage flux between the rotor, the residual magnetic flux density of the magnet is 1.0 [T] or more, and the stator and the rotor arranged to face the rotor. An alternating current generator for vehicles, characterized in that the magnetic gap between and is set to 0.55 to 0.65 [mm]. 2. The vehicle alternator according to claim 1, wherein the magnet is covered by a cover portion. 3. The vehicular AC generator according to claim 2, wherein the covering member is supported by a cylindrical support portion inside the claw-shaped magnetic pole. . 4. The vehicle alternator according to claim 3, wherein the support portion has elasticity. 5. The vehicle alternator according to claim 3 or 4, wherein the cover portion and the support portion are integrally formed by molding. 6. The vehicle alternator according to claim 5, wherein the cover portion and the support portion are made of polyamide resin.