JP3041884B2 - AC generator for vehicles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an automotive alternator.

2. Description of the Related Art As a vehicle AC generator, there is a vehicle AC generator in which a rotor having a field winding is arranged inside a stator having a multi-phase winding.

In this case, a plurality of sets of claw-shaped magnetic poles are provided on the outer periphery of the rotor to increase the number of magnetic poles formed by the field winding, and a plurality of slots (grooves) are provided in the stator.
Are formed at a rate of one per phase and one pole according to the number of phases of the windings and the number of magnetic poles of the rotor. The above-mentioned windings are arranged in these grooves, and between each groove, a toothed iron core is formed. ing.

[Problems to be Solved by the Invention] However, in the automotive alternator provided with the above-described claw-shaped magnetic poles, the slots are formed at a ratio of one per phase and one pole, so that each magnetic pole of the rotor is provided. When the stators 101 and 102 and the stator core 103 of the stator are at a relative position as shown in FIG.
3 has time to leak.

The leakage of the magnetic flux not only reduces the effective magnetic flux but also generates a pulsation of the magnetic flux, which disturbs the generated voltage and disturbs the output waveform, and causes a ripple when rectified to DC.

In recent years, such ripples have become electronic,
There is a demand for further reduction in IC power supply for vehicles, and a high-quality DC power supply with less noise such as ripple and voltage fluctuation is required.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce a ripple when a DC is rectified by reducing a leakage magnetic flux in an automotive alternator.

[Means for Solving the Problems] In order to achieve the above object, according to the first aspect of the present invention, a plurality of grooves for accommodating a multi-phase stator winding and a plurality of toothed cores located between the grooves. , A plurality of magnetic poles facing the plurality of toothed iron cores of the stator are formed, a rotor driven to rotate, and a field winding for supplying a field to the rotor In a vehicle alternator comprising:
The magnetic poles of the rotor are arranged such that a single toothed core of the stator is located over two tapered magnetic poles adjacent in the direction of rotation of the rotor;
The number of the plurality of toothed iron cores is set to 2 per phase and the number of poles of the stator winding and the number of poles of the magnetic pole, and the stator winding is a multi-phase first coil. It is a technical means to provide a group and a multi-phase second coil group which is arranged with an electrical angle shifted so that an output does not overlap with each phase coil of the first coil group.

According to the second aspect of the present invention, in the first aspect, the first coil group and the second coil group have three phases, and the phase coils of both coil groups are shifted by π / 6 from each other to the stator core. The winding means is a technical means.

According to the third aspect of the present invention, a plurality of grooves in the axial direction are formed in the inner periphery, and a polyphase stator winding is arranged in the plurality of grooves, and a plurality of grooves are provided between the plurality of grooves. A stator having a toothed core, a field winding having a field winding, rotatably disposed inside the stator, and having a plurality of magnetic poles facing the plurality of toothed cores provided on an outer periphery thereof. And a magnetic pole of the rotor, wherein a single toothed iron core of the stator is positioned on two tapered magnetic poles adjacent to each other in the rotation direction of the rotor. And the number of the toothed iron cores is one for the number of phases of the stator winding and the number of the magnetic poles.
The fixed winding is a three-phase first winding.
A coil group and a three-phase second coil group, wherein each phase coil of the second coil group is shifted by π / 6 radian in electrical angle with respect to each phase coil of the first coil group, and the stator core is Is a technical means.

According to a fourth aspect of the present invention, in any of the first to third aspects, the first coil group and the second coil group are star-connected.

According to a fifth aspect of the present invention, the technical means according to the fourth aspect, wherein neutral points obtained by star-shaped connection of the first coil group and the second coil group are not connected to each other.

According to claim 6, in claim 5, a first rectifier for rectifying a polyphase AC output from the first coil group and a second rectifier for rectifying a polyphase AC output from the second coil group are provided. The technical means is that the outputs of both rectifiers are connected in parallel.

According to the first aspect, the magnetic poles of the rotor are arranged such that a single toothed core of the stator is located over two tapered magnetic poles adjacent to each other in the rotational direction of the rotor. The number of the plurality of toothed iron cores is set to two per phase for the number of stator winding phases and the number of magnetic poles of the rotor, and a groove between these toothed iron cores is provided. The stator winding accommodated in the first coil group includes a polyphase first coil group, and a polyphase second coil group arranged with an electrical angle shifted such that the output does not overlap with each phase coil of the first coil group. Since the magnetic flux formed between the adjacent magnetic poles of the rotor is less likely to be formed through the same tooth core, the time during which the magnetic flux leaks from the tooth core is reduced. Become. Therefore, the amount of decrease in the effective magnetic flux with respect to the stator winding caused by the leakage magnetic flux is reduced, and pulsation of the magnetic flux is less likely to occur. For this reason, the fluctuation of the generated voltage and the disturbance of the output waveform are reduced, and a stable voltage can be obtained when the voltage is rectified to DC.

According to the second aspect of the present invention, the above-described effects can be obtained in a practical three-phase vehicular alternator due to restrictions in the manufacturing process or demands for output characteristics.

According to the third aspect of the present invention, a stator having a substantially cylindrical shape and having a plurality of axial grooves formed on an inner periphery thereof, and a plurality of magnetic poles arranged rotatably inside the stator. The above-mentioned effects can be obtained in a practical three-phase vehicle alternator due to limitations in the manufacturing process or demands for output characteristics.

In the embodiment described later, the number of phases of the stator winding and the number of magnetic poles are set to 2 per phase, and the teeth 31 of the first three-phase coil group in the embodiment described later. A pair of toothed iron cores (21a, 22a), (23a, 24a), (25a, 26a) formed between the equally-spaced grooves 21, 23, 25 accommodating 32, 33, and a second three-phase The toothed core 21 is divided by equally spaced grooves 22, 24, and 26 for accommodating the coils 34, 35, and 36 of the coil group.
a, 22a, 23a, 24a, 25a, 26a.

In addition, the first coil group and the second coil group can adopt the configurations described in claims 4 and 5.
Rectification can be achieved with the described configuration.

[Example] Next, an automotive alternator according to the present invention will be described based on an example.

FIG. 1 shows an alternator 1 of the present embodiment.
A rotor (rotor) 10 rotatably supported by the frame 2 by bearings 3 and 4 is disposed inside the frame 2, and a substantially cylindrical rotor disposed so as to surround the rotor 10 is disposed outside the rotor 2. A stator (stator) 20 is provided.

2, a rotor coil 14 as a field coil is wound around rotor cores 12 and 13 to which a rotating shaft 11 driven by an engine is fitted via a belt (not shown). On the outer circumference of 12, 13,
Each of the rotor cores 12 and 13 is provided with six claw-shaped magnetic poles 12a and 13a integrally formed on the rotor cores 12 and 13, respectively.
They are alternately arranged on the outer periphery of the rotor 10.

On the other hand, as shown in FIG. 3, the stator core 20 is formed by bending a plate-like core obtained by punching out portions corresponding to the slots (grooves) 21 to 26 and overlapping and winding it into a substantially cylindrical shape.
The toothed iron cores 21a to 26a are formed between the slots 21 to 26, and the stator coils 30 are arranged in the slots 21 to 26.

In the present embodiment, in order to obtain two sets of three-phase alternating current for the twelve magnetic poles of the rotor 10, the stator core
Each of the 20a has 72 slots and a toothed iron core. Here, as shown in FIG. 4, the slots 21, 23, and 25 each have a three-phase main coil as the stator coil 30.
31, 32, and 33, and slots 22, 24, and 26 are provided with three-phase slave coils 34, 35, and 36 with a phase difference of 60 ° in electrical angle, respectively. Each of the main coils 31, 32, and 33 has a phase difference of 30 ° in electrical angle with respect to each of the main coils 31, 32, and 33.

When the stator core 20a is viewed through the rotor 10, for example, as shown in FIG. 5, even if the relative positions of the toothed cores 21a with respect to the magnetic poles 12a and 13a of the rotor 10 overlap with each other, as shown in FIG. And the overlap between the magnetic poles 12a and 13a becomes very small.

For this reason, at this time, the magnetic flux between the magnetic poles 12a and 13a formed via the toothed iron core 21a becomes very small, and the leakage magnetic flux can be suppressed.

As a result, the disturbance of the magnetic flux linked to each of the main coils 31 to 33 can be suppressed.

Such leakage magnetic flux is similarly reduced for the other toothed iron cores 22a to 26a, so that disturbance of the magnetic flux linking the subordinate coils 34 to 36 can also be suppressed.

In the alternator 1 of the present embodiment having the above configuration,
Each stator coil 30, as shown in FIG.
Three-phase full-wave rectification is performed by rectifiers 5 and 6 each of which is Y-connected to each of 31 to 33 and subordinate coils 34 to 36 and includes six diodes.
In addition, the voltage is supplied to the vehicle load 8, and is supplied to a voltage adjusting device 9 that controls the energization of the rotor coil 14 in accordance with the terminal voltage of the vehicle battery 7 to keep the terminal voltage of the vehicle battery 7 constant.

The alternator 1 having the above configuration generates electric power according to the vehicle load 8 when the rotor 10 is driven with the start of the engine.

At this time, the output voltage waveforms of the main coils 31 to 33 and the slave coils 34 to 36 of the stator coil 30 appear as shown by the solid line A and the broken line B in FIG.
Since a phase difference of 30 ° in electrical angle is given to the main coils 31 to 33, the waveform of the combined voltage V that has been three-phase full-wave rectified by the rectifiers 5 and 6 respectively is as shown by a solid line C. Appear, the main coil 31-33 and the slave coil 34-
This combined voltage waveform due to the main coil 31
The difference between the maximum voltage value and the minimum voltage value becomes smaller as compared with the single voltage waveform in the case where only .about.33 is rectified.

Here, the difference between the maximum value Vmax and the minimum value Vmin of the composite voltage V
Veq (= Vmax-Vmin) is (E is the maximum value of the sine wave generated in the stator coil 30.) The average value of the composite voltage V is Here, when the ripple rate Veq / is obtained, Veq / = 0.034.

On the other hand, as shown by the broken line D, in a conventional vehicle AC generator provided with one slot per pole per phase and not having a dependent coil, only one set of three-phase coils is used as a stator coil. A difference v eq (= v max−v min) between the maximum value v max and the minimum value v min of the combined voltage v
Is (Where E is the maximum value of the sine wave generated in the stator coil 30), and the average value of the resultant voltage v is Here, when the ripple rate v eq / is obtained, v eq / = 0.14.

Therefore, according to the present embodiment, the ripple rate can be significantly reduced as compared with the conventional one.

As described above, in the present invention, the number of the toothed cores of the stator core is two per phase and the number of the magnetic poles of the rotor for the number of phases of the stator coil and the number of magnetic poles of the rotor. And the disturbance of the magnetic flux to each stator coil is reduced.

As a result, the ripple of the rectified output voltage is reduced, and a high-quality DC power supply with less voltage fluctuation can be provided.

In this embodiment, the three-phase AC generator is shown, but the present invention can be applied to five-phase and seven-phase.

[Brief description of the drawings]

FIG. 1 is a sectional view of an alternator showing an embodiment of the present invention,
FIG. 2 is a perspective view showing the rotor of this embodiment, FIG. 3 is a side elevational view showing the stator core of this embodiment, FIG. 4 is a schematic diagram for explaining the stator, and FIG. FIG. 6 is a circuit diagram showing a power supply circuit of a vehicle using the alternator of the present embodiment,
FIG. 7 is a waveform diagram showing an output voltage waveform of the alternator of the present embodiment, and FIG. 8 is a developed plan view for explaining the relationship between a conventional stator and magnetic poles. In the figure, 1 ... alternator (vehicle alternator), 10 ...
... rotor (rotor), 12a, 13a ... magnetic pole (claw-shaped magnetic pole), 14 ... rotor coil, 20 ... stator (stator), 21, 23, 25 ... slot (multiple grooves), 22 ,twenty four,
26 ... slots (a plurality of grooves), 21a to 26a ... toothed iron cores, 31 to 33 ... main coils (polyphase stator windings).

Claims (6)

(57) [Claims] A plurality of grooves for accommodating a multi-phase stator winding;
A stator formed with a plurality of toothed cores located between the grooves, a rotor formed with a plurality of magnetic poles opposed to the plurality of toothed cores of the stator, and driven to rotate; and the rotor A field winding for supplying a field to the rotor, wherein the magnetic pole of the rotor is such that the single toothed iron core of the stator is adjacent to the rotor in the rotational direction of the rotor. The plurality of toothed cores are arranged so as to be located over the two tapered magnetic poles, and the number of the plurality of toothed cores is 2 per phase per pole with respect to the number of phases of the stator winding and the number of poles of the magnetic pole. Wherein the stator windings include a polyphase first coil group, and a polyphase second coil group arranged at staggered electrical angles so that the output of each phase coil of the first coil group does not overlap. An alternator for a vehicle, comprising: 2. The method according to claim 1, wherein the first coil group and the second coil group have three phases, and the respective phase coils of both coil groups are wound around the stator core while being shifted from each other by π / 6. The alternator for a vehicle according to claim 1, wherein: 3. A plurality of grooves in the axial direction are formed in the inner periphery of the cylinder. A plurality of grooves are provided with a plurality of stator windings, and a plurality of toothed cores are formed between the plurality of grooves. And a rotor having a field winding, rotatably disposed inside the stator, and having a plurality of magnetic poles provided on an outer periphery thereof opposed to the plurality of tooth-shaped cores. In the vehicle alternator, the magnetic poles of the rotor are arranged such that a single toothed core of the stator is positioned over two tapered magnetic poles adjacent to each other in a rotation direction of the rotor. The number of the plurality of toothed iron cores is set to 2 per phase per pole with respect to the number of phases of the stator winding and the number of poles of the magnetic pole. First coil group and three-phase second coil group
A coil group, and each phase coil of the second coil group is wound around the stator core at an electrical angle of π / 6 radian with respect to each phase coil of the first coil group. Vehicle alternator. 4. The automotive alternator according to claim 1, wherein said first coil group and said second coil group are star-connected. 5. The alternator for a vehicle according to claim 4, wherein the neutral points obtained by the star-shaped connection between the first coil group and the second coil group are not connected to each other. 6. A rectifier comprising: a first rectifier for rectifying a polyphase AC output from the first coil group; and a second rectifier for rectifying a polyphase AC output from the second coil group. The alternator for a vehicle according to any one of claims 1 to 5, wherein the outputs are connected in parallel.