JP2016086483A - Ac generator for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a generated magnetic flux to implement a high voltage/high output AC generator for a vehicle.SOLUTION: A rotor includes: a plurality of salient poles 11 provided so as to outwardly protrude from the rotation center; a plurality of field coils 12 disposed around the plurality of salient poles; and a first slip ring, second slip ring, and common slip ring. The plurality of field coils 12 are divided into two groups; a winding direction of field coils 12 (first field coils) of one group is reverse to that of field coils (second field coils) of the other group. The first field coils and second field coils are alternately disposed around the plurality of salient poles. The first field coils are connected in series; one end of the series is connected to the first slip ring and the other end is connected to the common slip ring. The second field coils are connected in series; one end of the series is connected to the second slip ring and the other end is connected to the common slip ring.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicular AC generator for large vehicles such as trucks (lorries), and more particularly to a rotor field winding thereof.

  An automotive alternator (hereinafter referred to as “alternator”) includes an alternator body and a rectifier that converts alternating current output from the alternating current generator into direct current. The AC generator body is composed of a rotor and a stator. By driving the rotor by the engine, the AC generator body generates power.

  As shown in FIG. 7, the alternator provides an excitation current to the rotor 5 including the rotor coil 50, the stator 24 including the stator core 21 and the stator coil 22, the pulley 6 provided on the shaft of the rotor 5, and the rotor coil 50. And a brush 7 for supply.

  As shown in FIG. 8, the stator 24 includes a stator core 21 and a stator coil 22, and is supported by a front cover 25 and a rear cover 26 (both see FIG. 7). The stator core 21 is formed by superposing thin iron plates, and a plurality of slots (grooves) 23 are provided inside the stator core 21 so that the stator coil 22 can be inserted therein. The stator core 21 is a magnetic flux passage formed so that the magnetic flux emitted from the pole core (magnetic pole) of the rotor 5 effectively intersects the stator coil. Three independent stator coils 22 are wound around the stator core 21, and an alternating voltage is generated as the rotor 5 rotates. The connection of the stator coil 22 is generally a Y connection.

  9 shows a perspective view of the rotor 5 called a claw pole type, and FIG. 10 shows a front view thereof. The rotor 5 includes a rotor coil 50 disposed in the center, two magnetic poles 51 and 51 disposed so as to sandwich the rotor coil 50 from above and below and surround the periphery (circumference) with claw-shaped protrusions, A rotor coil 50 and a shaft 52 penetrating the center of the magnetic poles 51, 51. The magnetic pole 51 has 6 to 8 claws. FIG. 11 shows a perspective view of the rotor coil 50. The rotor coil 50 is formed with a through hole 50a through which the shaft 52 is inserted.

  As shown in FIG. 10, the rotor 5 further includes two slip rings 53, 53 that supply a current for exciting the rotor coil 50. The slip ring 53 is composed of a ring made of copper, brass, stainless steel, or the like, and an insulator provided between the ring and the shaft 52. The brush 7 slides on the circumference of the ring to supply current to the rotor coil 50.

  When a current is supplied to the rotor coil 50, the two magnetic poles 51 and 51 are magnetized to have different polarities. N shown on the claws of the magnetic poles 51 and 51 in FIGS. 9 and 10 indicates the N pole of the magnet, and S indicates the S pole of the magnet. Around the rotor, N and S poles corresponding to the number of claws of the magnetic pole 51 are alternately generated. A pulley 6 provided at the end of the shaft 52 is rotated by receiving power from the engine via a belt, whereby a magnetic field (magnetic flux) penetrating the stator coil is changed, and an electromotive force is generated.

  The voltage output by the alternator changes according to the rotational speed (corresponding to the engine rotational speed). For this reason, a control device called a voltage regulator (not shown) monitors the output voltage and adjusts the output voltage of the alternator. With the voltage regulator, electric power is supplied at a voltage (12 V for a passenger car) at which electric components of the automobile normally operate even under ever-changing driving conditions.

JP 2001-086668 A JP 2002-064950 A JP 2013-183535 A JP 2013-090406 A Japanese Patent No. 4867978

  In recent years, alternators with voltage control and power generation control are used in the passenger car industry, and efforts to improve fuel efficiency by increasing the voltage and output of in-vehicle systems are accelerating.

  Similar technology and efforts are desired for trucks as well as passenger cars, but the operating voltage of trucks is 24V, which is characterized by a higher voltage than passenger cars. Since the magnitude of the electromotive force generated by electromagnetic induction is proportional to the rate of change of the magnetic field, in order to further increase the voltage of the alternator according to the track operating voltage, the current (rotor field current) that flows through the rotor coil 50 is increased. ) And the magnetic flux passing through the stator coil 22 needs to be increased.

  However, with the conventional claw pole type alternator, it is difficult to increase the current flowing through the rotor coil 50. In order to increase the current, it is necessary to increase the voltage applied to the rotor coil 50 (increase the voltage) or decrease the resistance of the rotor coil 50 (reduction in resistance). The operating voltage of the track is 24V, and cannot be increased unconditionally, and it is difficult to cope with higher voltages.

  On the other hand, if the number of coil turns is reduced and the winding resistance is reduced, the current increases, but the generated magnetic field is proportional to the product of the rotor field current and the number of turns of the rotor coil 50. The product of the number of turns does not change and the generated magnetic field does not increase after all. In a claw pole type rotor that allows only a constrained space at the center of the rotor, it is difficult to increase the magnetic flux due to a trade-off relationship between the field current and the number of turns of the rotor coil.

  Further, the conventional alternator has a problem that when the field current is increased, magnetic flux saturation occurs in the rotor itself, which makes it difficult to achieve high voltage and high output. The magnetic pole of the claw pole type rotor is made of cast iron. However, since the saturation magnetic flux density is low, magnetic flux saturation is likely to occur due to an increase in field current, and high voltage and high output cannot be achieved.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an automotive alternator that can increase the magnetic flux generated by the rotor of the alternator, thereby enabling high voltage and high output. To do.

  The vehicle alternator according to the present invention includes a rotating rotor and a stator that is disposed to face the periphery of the rotor. The rotor includes a plurality of salient poles provided so as to protrude from the center of rotation, a plurality of field coils respectively disposed on the plurality of salient poles, a first slip ring connected to the field coil, and a second A slip ring and a common slip ring.

  The plurality of field coils are divided into two groups, and the winding direction of one group of the field coils (first field coil) of these two groups and the field coil (second field) of the other group. The direction of winding of the magnetic coil is the opposite direction. The first field coil and the second field coil are alternately arranged on a plurality of salient poles. The first field coil is connected in series, one end of which is connected to the first slip ring and the other end is connected to the common slip ring. The second field coil is connected in series, with one end connected to the second slip ring and the other end connected to the common slip ring.

  When generating a high voltage, it is only necessary to energize both the first slip ring and the second slip ring. When generating a low voltage, it is necessary to energize either the first slip ring or the second slip ring. Good.

  The salient pole is preferably an electromagnetic steel plate.

  According to the present invention, a rotor having a novel structure in which a field coil is wound for each salient pole (rotor slot) is employed instead of a claw pole type in which a continuous coil concentrated in the center is used, and field coils are connected in parallel. Since the winding resistance has been reduced, the magnetic flux generated by the rotor is increased to achieve higher voltage and higher output of the vehicle alternator (alternator), and the field coils are divided into two groups. Since the current is supplied to each group by the first slip ring, the second slip ring, and the common slip ring, the generated voltage can be switched by turning on and off the current.

It is a front view of the rotor which concerns on one Embodiment of this invention. It is sectional drawing of the rotor which concerns on one Embodiment of this invention. 1 is a perspective view of a rotor assembly according to an embodiment of the present invention. It is a connection diagram at the time of dividing the field coil of the rotor which concerns on one Embodiment of this invention into 2 groups. It is a top view of the rotor which concerns on one Embodiment of this invention (The case where a power supply is connected only to the field coil of one group is shown). It is a top view of the rotor which concerns on one Embodiment of this invention (The case where a power supply is connected to the field coil of both groups is shown). It is a perspective view of an alternator. It is a perspective view of a stator. It is a perspective view of a claw pole type rotor. It is a front view of a claw pole type rotor. It is a perspective view of a rotor coil.

  FIG. 1 shows a front view of a rotor 1 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a rotor according to an embodiment of the present invention. FIG. 2 shows a state of the field coil 12 in a cross section passing through the rotation axis of the shaft 52 and the salient poles 11, but for convenience of illustration, the slip rings 13 a and 13 b are not shown in cross section. FIG. 3 is a perspective view of a rotor assembly (field coil) according to an embodiment of the present invention. Since the structure of the alternator and the stator is the same as that shown in FIGS. 7 and 8, common constituent elements are denoted by the same reference numerals and description thereof is omitted.

  The rotor assembly includes a rotor core 10 provided at the center of rotation, a plurality (16 in the illustrated example) of salient poles 11 provided so as to project from the rotor core 10, and a field coil wound around each of the salient poles 11. 12. The rotor core 10 is provided with a through hole 14 through which the shaft 52 is inserted.

  The field coils 12 are divided into two groups as will be described later. Let the symbol of the field coil belonging to one group L1 be 12-1, and the symbol of the field coil belonging to the other group L2 be 12-2. The field coils 12-1 and 12-2 are alternately arranged, and the field coils 12-1 and 12-2 are always adjacent to each other. The sign of the salient pole where the field coil 12-1 is arranged is 11-1, and the sign of the salient pole where the field coil 12-2 is arranged is 11-2.

  In the rotor according to this embodiment, the winding direction of the field coil 12-1 and the winding direction of the field coil 12-2 are opposite directions, so that the adjacent salient poles 11-1 and 11-2 have opposite polarities. Become.

  The rotor 1 includes three slip rings 13 a, 13 a, and 13 b that supply current for exciting the field coil 12. The slip rings 13 a, 13 a, and 13 b are composed of a ring made of copper, brass, stainless steel, or the like, and an insulator provided between the ring and the shaft 52. The brush 7 slides on the circumference of the ring to supply current to the field coil 12. Note that the number of the brushes 7 of the alternator according to the present embodiment is the same as the number of the slip rings 13.

  The salient pole 11 is configured by laminating electromagnetic steel plates.

  When a current is supplied to the field coil 12, adjacent salient poles 11 are magnetized in opposite polarities. 1 indicated by the salient pole 11 in FIG. 1 indicates the N pole of the magnet, and S indicates the S pole of the magnet. Around the rotor, N poles and S poles corresponding to the number of salient poles 11 are alternately generated. A pulley 6 provided at the end of the shaft 52 is rotated by receiving power from the engine via a belt, whereby a magnetic field (magnetic flux) penetrating the stator coil 22 is changed, and an electromotive force is generated.

  In this embodiment, the field coil 12 is divided into a plurality of groups according to the polarity (N pole, S pole) of the salient poles 11, and the field coils 12 included in the same group are connected in series, and in series. The groups of connected field coils 12 are connected in parallel. FIG. 4 shows an example in which the 16 field coils 12 of FIG. 3 are divided into two groups L1 and L2 of 8 pieces each. Eight field coils 12-1 included in the group L1 are connected in series. One end of the series connection is connected to the slip ring 13a, and the other end is connected to the slip ring 13b. Similarly, the eight field coils 12-1 included in the group L2 are connected in series. One end of the series connection is connected to the slip ring 13a, and the other end is connected to the slip ring 13b.

  5 and 6 are plan views of the rotor 5.

  FIG. 5 shows a state in which only the coil group L1 is energized via one of the two slip rings 13a so as to generate a lower voltage. Eight salient poles 11-1 jumping 1 slot become N poles. The other salient poles 11-2 naturally become other magnetic poles (S poles). Only the coil group L2 may be energized.

  FIG. 6 shows a state in which both of the two slip rings 13a and 13a are energized so that a higher voltage is generated, and a current is passed through both the coil groups L1 and L2. The eight salient poles 11-1 become N poles, and the eight salient poles 11-2 are excited by the field coil 12-2 to become S poles. N pole and S pole appear alternately.

  According to this embodiment, not a claw pole type in which one continuous coil is placed at the center of the rotor, but a structure in which a field coil is wound for each salient pole (rotor slot), and a plurality of field coils obtained by this structure The winding resistance can be reduced by connecting two in parallel. Thereby, the current flowing through the field coil (rotor field current) and the generated magnetic flux can be increased, and the voltage generated in the stator coil can be increased. For example, it is possible to generate a voltage exceeding 60 V, and it is possible to realize a high voltage and high output of the in-vehicle system.

  In the claw pole type rotor, it was difficult to increase the magnetic flux due to the trade-off relationship between the field current and the number of turns of the rotor coil, but according to this embodiment, the winding can be performed without reducing the number of turns of the field coil. Since the resistance is reduced, there is no trade-off problem in the claw pole type.

  In addition, three slip rings are provided (one is common). Only one pair of slip rings and common slip rings is energized, and magnetic flux is generated in half of the salient poles. Will it be a magnetic pole, or if both slip rings and common slip ring are energized to generate magnetic flux in all salient poles? (Adjacent salient poles are excited in opposite polarities, resulting in a strong magnetic field with a synergistic effect) ) Can be selected so that the generated voltage and generated power can be switched.

  In this embodiment, magnetic flux saturation is eliminated by using a salient pole material as an electromagnetic steel plate. Although the magnetic pole of the claw pole type rotor is made of cast iron, its saturation magnetic flux density is low, and magnetic flux saturation is likely to occur due to an increase in field current. However, this embodiment does not have such a problem.

  According to the alternator according to the present embodiment, it is possible to increase the amount of regenerative electric power (battery charge amount) during vehicle braking. The amount of power storage can be increased by increasing the capacity of the battery or using the secondary battery together. The power generation control frequency of the alternator can be increased. Moreover, the fuel consumption of the system can be improved.

  As mentioned above, although the embodiment to which the invention made by the present inventor is applied has been described, the present invention is not limited by the discussion and the drawings that form part of the disclosure of the present invention according to this embodiment. That is, it is needless to say that other embodiments, examples, operation techniques, and the like made by those skilled in the art based on this embodiment are all included in the scope of the present invention.

  The vehicle alternator of the present invention can be used in various vehicles.

10 Rotor core 11 Salient pole (rotor slot)
11-1 Salient pole of first field coil 11-2 Salient pole of second field coil 12 Field coil 12-1 First field coil 12-2 Second field coil 13a Slip ring 13b Common slip ring 14 Through hole L1, L2 Coil group in which a plurality of field coils are connected in series

Claims (3)

A rotating rotor;
A stator disposed oppositely around the rotor,
The rotor includes a plurality of salient poles provided so as to protrude from a rotation center to the periphery, a plurality of field coils respectively disposed on the plurality of salient poles, and a first slip ring connected to the field coil A second slip ring and a common slip ring,
The plurality of field coils are divided into two groups, and the winding direction of the first field coil, which is the field coil of one of the two groups, and the field coil of the other group. A direction opposite to the winding direction of a certain second field coil,
The first field coil and the second field coil are alternately arranged on the plurality of salient poles,
The first field coil is connected in series, one end thereof is connected to the first slip ring, the other end is connected to the common slip ring,
The second field coil is connected in series, one end thereof is connected to the second slip ring, and the other end is connected to the common slip ring. The vehicle alternator according to claim 1,
When generating a high voltage, energize both the first slip ring and the second slip ring,
2. The vehicular AC generator according to claim 1, wherein when a low voltage is generated, either one of the first slip ring and the second slip ring is energized. The vehicle alternator according to claim 1 or 2,
The vehicular AC generator, wherein the salient pole is an electromagnetic steel plate.

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