AUTOMOTIVE ALTERNATOR

BACKGROUND OF THE INVENTION

[0001]

1. Field of the Invention

The present invention relates to an automotive alternator that is mounted to a motorcycle or a four-wheeled motor vehicle, and particularly relates to an automotive alternator that has: a stator core in which slots are formed at a ratio of one slot per phase per pole; and a stator winding in which phase windings are configured into zigzag windings.

[0002]

2. Description of the Related Art

Conventional automotive alternators include a stator that has: a stator core in which slots are formed at a ratio of two slots per phase per pole; and a stator winding that is made of six winding portions that are mounted into respective slot groups that are constituted by slots that are disposed at intervals of six slots (see Patent Literature 1, for example).

[0003]
In this conventional automotive alternator, each of the winding portions is a full-pitch winding in which a conductor wire is wound into a wave winding in slots that are disposed at intervals of six slots, and the stator winding is configured by alternating-current connecting (AC-connecting), such as wye-connecting, for example, three phase windings that are each configured by connecting in series two winding portions that have a phase difference of 30 electrical degrees to reduce 6f electromagnetic noise. Moreover, the windings that are configured by connecting in series the two winding portions that have a mutual phase difference are zigzag windings.

CITATION LIST PATENT LITERATURE

[0004]
[Patent Literature l] Japanese Patent Laid-Open No. 2002-354736 (Gazette)

[0005]
In conventional automotive alternators, the two winding portions that are connected in series are constituted by full-pitch windings that have a phase difference of 30 electrical degrees from each other. Thus, because the electromagnetic force phases of the two winding portions that are connected in series are offset, resultant electromotive forces from the respective phase windings are smaller than electromotive forces from phase windings that are constituted by full-pitch windings that do not have phase differences. Due to electromagnetic force phase shift in phase windings of this kind, and armature reaction magnitude relationships in the alternator, stator phase currents decrease in a low-speed rotation range in conventional automotive alternators that have a stator winding that is configured by wye-connecting three phase windings that are constituted by zigzag windings compared to general automotive alternators that have a stator winding that is configured by wye-connecting three phase windings that are constituted by full-pitch windings that do not have phase differences, and one problem has been that output decreases.

[0006]
In conventional automotive alternators, because the slots are formed at a ratio of two slots per phase per pole, the outside diameter of the stator core is increased in size. Because the rotor is increased in size with this increase in the size of the stator core, the moment of inertia of the rotor is increased, increasing mechanical loss, and another problem has been that the efficiency of the alternator decreases.

SUMMARY OF THE INVENTION

[0007]
The present invention aims to solve the above problems and an object of the present invention is to provide an automotive alternator that can achieve reductions in stator core size by using a stator core in which slots are formed at a ratio of one slot per phase per pole, and that can suppress decreases in output in a low-speed rotation range that result from zigzag windings.

[0008]
In order to achieve the above object, according to one aspect of the present invention, there is provided an automotive alternator including: a rotor that is rotatably supported by a housing; and a stator including: a cylindrical stator core in which slots are formed at a ratio of one slot per phase per pole; and a stator winding that is configured by alternating-current connecting three phase windings that are mounted into the stator core, the stator being supported by the housing so as to surround the rotor. Each of the phase windings is configured by connecting in series a first winding portion and a second winding portion that have a phase difference that corresponds to an electrical angle of n/6 from each other, the first winding portion is configured by winding a conductor wire into a full-pitch winding, the second winding portion is configured by winding a conductor wire so as to alternate repeatedly between a 2n/3 short-pitch winding and a 4n/3 long-pitch winding, and a turn ratio between the first winding portion and the second winding portion is V2.

[0009]
According to the present invention, the phase windings are each configured by connecting in series a first winding portion and a second winding portion that have a phase difference that corresponds to an electrical angle of n/6 from each other, the first winding portion is formed by winding a conductor wire into a full-pitch winding, the second winding portion is formed by winding a conductor wire so as to alternate repeatedly between a 2n/3 short-pitch winding and a 4n/3 long-pitch winding, and the turn ratio of the first winding portion and the second winding portion is V2. Decreases in output in a low-speed rotation range that result from zigzag windings are thereby suppressed.

Because the slots are formed at a ratio of one slot per phase per pole, increases in the size of the stator core can be suppressed. Thus, reductions in size of the rotor are made possible, moment of inertia of the rotor can be reduced, and mechanical loss can be suppressed, increasing the efficiency of the alternator.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]

Figure 1 is a longitudinal cross section that shows an automotive alternator according to Embodiment 1 of the present invention;

Figure 2 is an electrical circuit diagram of the automotive alternator according to Embodiment 1 of the present invention;

Figure 3 is a table that explains slot groups into which are mounted first winding portions that constitute phase windings in the automotive alternator according to Embodiment 1 of the present invention;

Figure 4 is a table that explains slot groups into which are mounted second winding portions that constitute phase windings in the automotive alternator according to Embodiment 1 of the present invention;

Figures 5A through 5F are developed projections that explain mounted states of winding portions that constitute phase windings in the automotive alternator according to Embodiment 1 of the present invention;

Figure 6 is an output characteristics graph of the automotive alternator according to Embodiment 1 of the present invention;

Figure 7 is a connection diagram that explains configuration of a stator winding in an automotive alternator according to Embodiment 2 of the present invention;

Figure 8 is a table that explains slot groups into which an X phase winding is mounted in the automotive alternator according to Embodiment 2 of the present invention;

Figure 9 is a table that explains slot groups into which a Y phase winding and a Z phase winding are mounted in the automotive alternator according to Embodiment 2 of the present invention;

Figures 10A through 10E are developed projections that explain a mounted state of an X phase winding in the automotive alternator according to Embodiment 2 of the present invention;

Figures 11A through HE are developed projections that explain a mounted state of a Z phase winding in the automotive alternator according to Embodiment 2 of the present invention; and

Figures 12A through 12E are developed projections that explain a mounted state of a Y phase winding in the automotive alternator according to Embodiment 2 of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011]
Preferred embodiments of an automotive alternator according to the present invention will now be explained with reference to the drawings.

[0012] Embodiment 1
Figure 1 is a longitudinal cross section that shows an automotive alternator according to Embodiment 1 of the present invention, Figure 2 is an electrical circuit diagram of the automotive alternator according to Embodiment 1 of the present invention, Figure 3 is a table that explains slot groups into which are mounted first winding portions that constitute phase windings in the automotive alternator according to Embodiment 1 of the present invention, Figure 4 is a table that explains slot groups into which are mounted second winding portions that constitute phase windings in the automotive alternator according to Embodiment 1 of the present invention, Figures 5A through 5F are developed projections that explain mounted states of winding portions that constitute phase windings in the automotive alternator according to Embodiment 1 of the present invention, and Figure 6 is an output characteristics graph of the automotive alternator according to Embodiment 1 of the present invention. Moreover, 1 through 36 in Figure 5 are slot numbers.

[0013]
In Figures 1 and 2, an automotive alternator 1 includes: a housing 4 that is constituted by a front bracket 2 and a rear bracket 3 that are each approximately bowl-shaped and made of aluminum; a shaft 6 that is rotatably supported in the housing 4 by means of bearings 5; a pulley 7 that is fixed to an end portion of the shaft 6 that extends out frontward from the housing 4; a rotor 8 that is fixed to the shaft 6 and that is disposed inside the housing 4; a stator 20 that is fixed to the housing 4 so as to surround the rotor 8; a pair of slip rings 12 that are fixed to a rear end of the shaft 6, and that supply electric current to the rotor 8; a pair of brushes 13 that slide on respective surfaces of the slip rings 12; a brush holder 14 that accommodates the brushes 13; a rectifier 15 that is electrically connected to the stator 20 so as to convert alternating current that is generated by the stator 20 into direct current; and a voltage regulator 16 that is disposed so as to be fixed adhesively to a heatsink 17 that is fitted over the brush holder 14, and that adjusts magnitude of an alternating-current voltage that is generated by the stator 20.

[0014]

The rotor 8 includes: a field coil 9 that generates magnetic flux on passage of an excitation current; a pole core 10 that is disposed so as to cover the field coil 9, and in which twelve magnetic poles are formed by the magnetic flux; and the shaft 6, which is fitted centrally through the pole core 10. Fans 11 are fixed to two axial end surfaces of the pole core 10 by welding, etc.

[0015]
The stator 20 is prepared by laminating magnetic steel plates annularly, for example, and includes: a stator core 21 in which thirty-six slots are arranged so as to have openings on an inner circumferential side at a pitch corresponding to an electrical angle of n/3 (= 60 degrees) circumferentially, and that is disposed so as to be held from two axial ends by the front bracket 2 and the rear bracket 3 and surround the pole core 10 so as to ensure a uniform gap from an outer peripheral surface of the pole core 10 of the rotor 8; and a stator winding 22 that is mounted to the stator core 21.

[0016]
Next, construction of the stator winding 22 will be explained with reference to Figures 2 through 5.
As shown in Figures 3 and 5A, the XI winding portion 26 is formed by winding a single conductor wire 24 that is made of a copper wire that is coated with an insulator for one turn into a wave winding in a forward direction in slots including Slot Numbers 12, 15, 18, 21, etc., through 6, and 9 that are arranged at a pitch that corresponds to an electrical angle of n (= 180 degrees), and then by winding the conductor wire 24 for two turns into a wave winding in a reverse direction in slots including Slot Numbers 6, 3, 36, 33, etc., through 12, and 9. This XI winding portion 26 is a three-turn wave winding that is configured by winding the conductor wire 24 into full-pitch windings in a slot group that is constituted by the slots at Slot Numbers 12, 15, 18, 21, etc., through 6, and 9. Two ends of the XI winding portion 26 extend outward from the slots at Slot Numbers 9 and 12. Moreover, the forward direction is the direction in which the slot numbers increase, and the reverse direction is the direction in which the slot numbers decrease.

[0017]
An X2 winding portion 27 is configured by connecting an X21 winding portion 27a and an X22 winding portion 27b in series. As shown in Figures 4 and 5B, the X21 winding portion 27a is formed by winding a conductor wire 24 for three turns into a wave winding in the forward direction in slots including Slot Numbers 11, 15, 17, 21, etc., through 5, and 9 that are arranged so as to alternately occupy intervals that correspond to electrical angles of 2n/3 (= 120 degrees) and 4n/3 (= 240 degrees). This X21 winding portion 27a is a three-turn wave winding that is configured by winding the conductor wire 24 so as to alternate repeatedly between a 2n/3 short-pitch winding and a 4n/3 long-pitch winding. Two ends of the X21 winding portion 27a extend outward from the slots at Slot Numbers 9 and 11.

[0018]
As shown in Figures 4 and 5B, the X22 winding portion 27b is formed by winding a conductor wire 24 for three turns into a wave winding in the forward direction in slots including Slot Numbers 8, 12, 14, 18, etc., through 2, and 6 that are arranged so as to alternately occupy intervals that correspond to electrical angles of 2n/3 and 4n/3. This X22 winding portion 27b is a three-turn wave winding that is configured by winding the conductor wire 24 so as to alternate repeatedly between a 2n/3 short-pitch winding and a 4n/3 long-pitch winding. Two ends of the X22 winding portion 27b extend outward from the slots at Slot Numbers 6 and 8.

[0019]

The X2 winding portion 27, in which the X21 winding portion 27a and the X22 winding portion 27b are connected in series, is configured by connecting an end portion of the X21 winding portion 27a that extends outward from the slots at Slot Number 9 and an end portion of the X22 winding portion 27b that extends outward from the slots at Slot Number 8. Two ends of the X2 winding portion 27 extend outward from the slots at Slot Numbers 6 and 11. Next, an X phase winding 25 in which the XI winding portion 26 and the X2 winding portion 27 are connected in series is configured by connecting an end portion of the XI winding portion 26 that extends outward from the slots at Slot Number 12 and an end portion of the X2 winding portion 27 that extends outward from the slots at Slot Number 6. Two ends of the X phase winding 25 extend outward from the slots at Slot Numbers 9 and 11.

[0020]
A Y phase winding 28 is configured by connecting in series a Yl winding portion 29 that functions as a first winding portion and a Y2 winding portion 30 that functions as a second winding portion.
As shown in Figures 3 and 5C, the Yl winding portion 29 is formed by winding a conductor wire 24 for one turn into a wave winding in a forward direction in slots including Slot Numbers 5, 8, 11, 14, etc., through 35, and 2 that are arranged at a pitch that corresponds to an electrical angle of n, and then by winding the conductor wire 24 for two turns into a wave winding in the reverse direction in slots including Slot Numbers 35, 32, 29, 26, etc., through 5, and 2. This Yl winding portion 29 is a three-turn wave winding that is configured by winding the conductor wire 24 into full-pitch windings in a slot group that is constituted by the slots at Slot Numbers 2, 5, 8, 11, etc., through 32, and 35. Two ends of the Yl winding portion 29 extend outward from the slots at Slot Numbers 2 and 5.

[0021]

A Y2 winding portion 30 is configured by connecting a Y21 winding portion 30a and a Y22 winding portion 30b in series. As shown in Figures 4 and 5D, the Y21 winding portion 30a is formed by winding a conductor wire 24 for three turns into a wave winding in the forward direction in slots including Slot Numbers 4, 8, 10, 14, etc., through 34, and 2 that are arranged so as to alternately occupy intervals that correspond to electrical angles of 2n/3 and 4n/3. This Y21 winding portion 30a is a three-turn wave winding that is configured by winding the conductor wire 24 so as to alternate repeatedly between a 2n/3 short-pitch winding and a 4n/3 long-pitch winding. Two ends of the Y21 winding portion 30a extend outward from the slots at Slot Numbers 2 and 4.

[0022]
As shown in Figures 4 and 5D, the Y22 winding portion 30b is formed by winding a conductor wire 24 for three turns into a wave winding in the forward direction in slots including Slot Numbers 1, 5, 7, 11, etc., through 31, and 35 that are arranged so as to alternately occupy intervals that correspond to electrical angles of 2n/3 and 4n/3. This Y22 winding portion 30b is a three-turn wave winding that is configured by winding the conductor wire 24 so as to alternate repeatedly between a 2n/3 short-pitch winding and a 4n/3 long-pitch winding. Two ends of the Y22 winding portion 30b extend outward at Slot Numbers 1 and 35.

[0023]
The Y2 winding portion 30, in which the Y21 winding portion 30a and the Y22 winding portion 30b are connected in series, is configured by connecting an end portion of the Y21 winding portion 30a that extends outward from the slots at Slot Number 2 and an end portion of the Y22 winding portion 30b that extends outward from the slots at Slot Number 1. Two ends of the Y2 winding portion 30 extend outward from the slots at Slot Numbers 4 and 35. Next, the Y phase winding 28, in which the Yl winding portion 29 and the Y2 winding portion 30 are connected in series, is configured by connecting an end portion of the Yl winding portion 29 that extends outward from the slots at Slot Number 2 and an end portion of the Y2 winding portion 30 that extends outward from the slots at Slot Number 4. Two ends of the Y phase winding 28 extend outward at Slot Numbers 5 and 35.

[0024]
A Z phase winding 31 is configured by connecting in series a Zl winding portion 32 that functions as a first winding portion and a Z2 winding portion 33 that functions as a second winding portion.
As shown in Figures 3 and 5E, the Zl winding portion 32 is formed by winding a conductor wire 24 for one turn into a wave winding in a forward direction in slots including Slot Numbers 10, 13, 16, 19, etc., through 4, and 7 that are arranged at a pitch that corresponds to an electrical angle of n, and then by winding the conductor wire 24 for two turns into a wave winding in the reverse direction in slots including Slot Numbers 4, 1, 34, etc., through 10, and 7. This Zl winding portion 32 is a three-turn wave winding that is configured by winding the conductor wire 24 into full-pitch windings in a slot group that is constituted by the slots at Slot Numbers 10, 13, 16, 19, etc., through 4, and 7. Two ends of the Zl winding portion 32 extend outward from the slots at Slot Numbers 7 and 10.

[0025]
A Z2 winding portion 33 is configured by connecting a Z21 winding portion 33a and a Z22 winding portion 33b in series. As shown in Figures 4 and 5F, the Z21 winding portion 33a is formed by winding a conductor wire 24 for three turns into a wave winding in the forward direction in slots including Slot Numbers 9, 13, 15, 19, etc., through 3, and 7 that are arranged so as to alternately occupy intervals that correspond to electrical angles of 2n/3 and 4n/3. This Z21 winding portion 33a is a three-turn wave winding that is configured by winding the conductor wire 24 so as to alternate repeatedly between a 2n/3 short-pitch winding and a 4n/3 long-pitch winding. Two ends of the Z21 winding portion 33a extend outward from the slots at Slot Numbers 7 and 9.

[0026]
As shown in Figures 4 and 5F, the Z22 winding portion 33b is formed by winding a conductor wire 24 for three turns into a wave winding in the forward direction in slots including Slot Numbers 6, 10, 12, 16, etc., through 36, and 4 that are arranged so as to alternately occupy intervals that correspond to electrical angles of 2n/3 and 4n/3. This Z22 winding portion 33b is a three-turn wave winding that is configured by winding the conductor wire 24 so as to alternate repeatedly between a 2n/3 short-pitch winding and a 4n/3 long-pitch winding. Two ends of the Z22 winding portion 33b extend outward from the slots at Slot Numbers 4 and 6.

[0027]
The Z2 winding portion 33, in which the Z21 winding portion 33a and the Z22 winding portion 33b are connected in series, is configured by connecting an end portion of the Z21 winding portion 33a that extends outward from the slots at Slot Number 7 and an end portion of the Z22 winding portion 33b that extends outward from the slots at Slot Number 6. Two ends of the Z2 winding portion 33 extend outward from the slots at Slot Numbers 4 and 9. Next, the Z phase winding 31, in which the Zl winding portion 32 and the Z2 winding portion 33 are connected in series, is configured by connecting an end portion of the Zl winding portion 32 that extends outward from the slots at Slot Number 10 and an end portion of the Z2 winding portion 33 that extends outward from the slots at Slot Number 4. Two ends of the Z phase winding 31 extend outward at Slot Numbers 7 and 9.

[0028]
Next, an end portion of the X phase winding 25 that extends outward from the slots at Slot Number 9, an end portion of the Y phase winding 28 that extends outward from the slots at Slot Number 5, and an end portion of the Z phase winding 31 that extends outward from the slots at Slot Number 7 are connected. Thus, a stator winding 22 is formed that is constituted by a three-phase alternating-current winding that is configured by wye-connecting the X phase winding 25, the Y phase winding 28, and the Z phase winding 31.
As shown in Figure 2, output ends of the X phase winding 25, the Y phase winding 28, and the Z phase winding 31 of the stator winding 22 that is configured in this manner are connected to the rectifier 15.

[0029]
Next, operation of the automotive alternator 1 will be explained. Moreover, in the automotive alternator 1, because there are twelve magnetic poles in the rotor 8, and the number of slots is 36, and the stator winding 22 is configured into a three-phase alternating-current winding, the slots are formed at a ratio of one slot per phase per pole.

[0030]
In the automotive alternator 1, an electric current is first supplied from a battery (not shown) through the brushes 13 and the slip rings 12 to the field coil 9 of the rotor 8 to generate magnetic flux. North-seeking (N) poles and South-seeking (S) poles are formed so as to alternate circumferentially on an outer circumferential surface of the pole core 10 by this magnetic flux. At the same time, rotational torque from an engine is transmitted from the output shaft of the engine to the shaft 6 by means of a belt and the pulley 7 to rotate the rotor 8. Thus, rotating magnetic fields are applied to the stator winding 22 in the stator 20 to generate electromotive forces in the stator winding 22. The alternating currents that are generated by these electromotive forces are rectified by the rectifier 15, to charge the battery, or be supplied to an electrical load. Magnitude of the alternating-current voltage that is generated in the stator 20 is adjusted by the voltage regulator 16.

[0031]
Now, voltage waveforms ei through e3 that are generated in the XI winding portion 26, the Yl winding portion 29, and the Zl winding portion
32 are expressed by Expressions (l) through (3).
e1(t) = 2sinωt ... Expression (l)
e2(t) = 2sin(ωt + n/3) ... Expression (2) e3(t) = 2sin(ωt + 2n/3) ... Expression (3)

Next, voltage waveforms e4 through eG that are generated in the X2 winding portion 27, the Y2 winding portion 30, and the Z2 winding portion
33 are expressed by Expressions (4) through (6).
e4(t) = 2sin(5n/6)sin(ωt + n/6) ... Expression (4)
es(t) = 2sin(5n/6)sin(ωt + n/2) ... Expression (5)
ee(t) = 2sin(5n/6)sin(ωt + 5n/6)... Expression (6)

[0032]
From Expressions (l) and (4), it can be seen that a phase difference 6 between the XI winding portion 26 and the X2 winding portion 27 is n/6 (= 30 degrees). Similarly, it can be seen from Expressions (2) and (5) that a phase difference 0 between the Yl winding portion 29 and the Y2 winding portion 30 is n/6, and from Expressions (3) and (6) that a phase difference 0 between the Zl winding portion 32 and the Z2 winding portion 33 is n/6.

[0033]
Next, results when an automotive alternator 1 that was configured in this manner was operated for forty minutes at 6,000 rpm, and then the rotational frequency was gradually increased from 0, and output current was measured are shown in Figure 6. Moreover, in Figure 6, a dotted chain line represents the output current in a comparative automotive alternator. The automotive alternator that functioned as the comparative example used a stator winding that was configured by wye-connecting an X phase winding, a Y phase winding, and a Z phase winding that were each formed by winding a conductor wire 24 into a full-pitch winding for nine turns instead of the stator winding 22.

[0034]
From Figure 6, it has been confirmed that the automotive alternator 1 can achieve higher output than the comparative automotive alternator in a low-speed rotation range of 1,800 to 4,000 rpm.

[0035]
According to Embodiment 1, the X phase winding 25, the Y phase winding 28 and the Z phase winding 31 that constitute the stator winding 22 are each constituted by a zigzag winding in which a first winding portion and a second winding portion that have a phase difference of 30 electrical degrees from each other are connected in series, the first winding portion is formed by winding a conductor wire 24 into a full-pitch winding, the second winding portion is formed by winding a conductor wire 24 so as to alternate repeatedly between a 2n/3 short-pitch winding and a 4n/3 long-pitch winding, and the turn ratio of the first winding portion and the second winding portion is 1:2. Thus, as can be seen from Figure 6, the phase current of the stator 20 is increased in a low-speed rotation range in this automotive alternator 1 compared to general automotive alternators that have a stator winding that is configured by wye-connecting three phase windings that are constituted by full-pitch windings that do not have phase differences, enabling output to be increased.

[0036]
Increased output compared to general automotive alternators that have a stator winding that is configured by wye-connecting three phase windings that are constituted by full-pitch windings that do not have phase differences can also be achieved without increasing the turn count of the X phase winding 25, the Y phase winding 28, and the Z phase winding 31. Thus, excessive temperature increases in the stator winding 22 are suppressed.

Because the slots are formed at a ratio of one slot per phase per pole, increases in the size of the outside diameter of the stator core 21 can be suppressed. Thus, the rotor 8 can be reduced in size, reducing the moment of inertia of the rotor 8, and mechanical loss is suppressed, enabling alternator efficiency to be increased.

[0037] Embodiment 2
Figure 7 is a connection diagram that explains configuration of a stator winding in an automotive alternator according to Embodiment 2 of the present invention, Figure 8 is a table that explains slot groups into which an X phase winding is mounted in the automotive alternator according to Embodiment 2 of the present invention, Figure 9 is a table that explains slot groups into which a Y phase winding and a Z phase winding are mounted in the automotive alternator according to Embodiment 2 of the present invention, Figures 10A through 10E are developed projections that explain a mounted state of an X phase winding in the automotive alternator according to Embodiment 2 of the present invention, Figures 11A through HE are developed projections that explain a mounted state of a Z phase winding in the automotive alternator according to Embodiment 2 of the present invention, and Figures 12A through 12E are developed projections that explain a mounted state of a Y phase winding in the automotive alternator according to Embodiment 2 of the present invention.

[0038]

In Figure 7, a stator winding 40 is a three-phase alternating-current winding that is formed by wye-connecting an X phase winding 41, a Y phase winding 44, and a Z phase winding 47 that have phase differences of that correspond to an electrical angle of 2n/3 (= 120 degrees) from with each other. The X phase winding 41 is configured by connecting in series an XI winding portion 42 that functions as a first winding portion and an X2 winding portion 43 that functions as a second winding portion that have a phase difference 9 that corresponds to an electrical angle of n/6 from each other. The Y phase winding 44 is configured by connecting in series a Yl winding portion 45 that functions as a first winding portion and a Y2 winding portion 46 that functions as a second winding portion that have a phase difference 8 that corresponds to an electrical angle of n/6 from each other. The Z phase winding 47 is configured by connecting in series a Zl winding portion 48 that functions as a first winding portion and a Z2 winding portion 49 that functions as a second winding portion that have a phase difference 9 that corresponds to an electrical angle of n/6 from each other. The X phase winding 41 is formed using a single conductor wire 24, and the Y phase winding 44 and the Z phase winding 47 are formed using a single conductor wire 24.

[0039]
Moreover, Embodiment 2 is configured in a similar manner to Embodiment 1 above except for the fact that the stator winding 40 is used instead of the stator winding 22.

[0040]
Next, the method for mounting the X phase winding 41 will be explained with reference to Figures 8 and 10.

[0041]
First, as shown in Figures 8 and 10A, an X21 winding portion 43a is formed by winding a single conductor wire 24 for three turns into a wave winding in the forward direction in slots including Slot Numbers 11, 15, 17, 21, etc., through 5, and 9 that are arranged so as to alternately occupy intervals that correspond to electrical angles of 2n/3 and 4n/3. Next, as shown in Figures 8 and 10B, the X22 winding portion 43b is formed by winding the conductor wire 24 that extends outward from the slots at Slot Number 9 for three turns into a wave winding in the forward direction in slots including Slot Numbers 8, 12, 14, 18, etc., through 2, and 6 that are arranged so as to alternately occupy intervals that correspond to electrical angles of 2n/3 and 4n/3. The X2 winding portion 43, in which the X21 winding portion 43a and the X22 winding portion 43b are connected in series, is configured thereby. This X2 winding portion 43 is a six-turn wave winding that is configured by winding the conductor wire 24 so as to alternate repeatedly between a 2n/3 short-pitch winding and a 4n/3 long-pitch winding.

[0042]
Next, as shown in Figures 8 and IOC, the conductor wire 24 that extends outward from the slots at Slot Number 6 is wound for two turns into a wave winding in the forward direction in slots including Slot Numbers 12, 15, 18, 21, etc., through 6, and 9 that are arranged at a pitch that that corresponds to an electrical angle of n. Then, as shown in Figure 10D, the conductor wire 24 that extends outward from the slots at Slot Number 9 is wound for one turn into a wave winding in the reverse direction in slots including Slot Numbers 6, 3, 36, 33, etc., through 12, and 9 to produce the XI winding portion 42. This XI winding portion 42 is a three-turn wave winding that is configured by winding the conductor wire 24 into full-pitch windings in a slot group that is constituted by the slots at Slot Numbers 12, 15, 18, etc., through 6, and 9.

[0043]

Thus, as shown in Figure 10E, the X phase winding 41, in which the XI winding portion 42 and the X2 winding portion 43 are connected in series, is made of a single conductor wire 24. Two ends of the X phase winding 41 extend outward from the slots at Slot Numbers 9 and 11.

[0044]
Next, the method for mounting the Y phase winding 44 and the Z phase winding 47 will be explained with reference to Figures 9, 11, and 12.

[0045]
First, as shown in Figures 9 and 11 A, a Z21 winding portion 49a is formed by winding a single conductor wire 24 for three turns into a wave winding in the forward direction in slots including Slot Numbers 9, 13, 15, 19, etc., through 3, and 7 that are arranged so as to alternately occupy intervals that correspond to electrical angles of 2n/3 and 4n/3. Next, as shown in Figures 9 and 11B, the Z22 winding portion 49b is formed by winding the conductor wire 24 that extends outward from the slots at Slot Number 7 for three turns into a wave winding in the forward direction in slots including Slot Numbers 6, 10, 12, 16, etc., through 36, and 4 that are arranged so as to alternately occupy intervals that correspond to electrical angles of 2n/3 and 4n/3. The Z2 winding portion 49, in which the Z21 winding portion 49a and the Z22 winding portion 49b are connected in series, is configured thereby. This Z2 winding portion 49 is a six-turn wave winding that is configured by winding the conductor wire 24 so as to alternate repeatedly between a 2n/3 short-pitch winding and a 4n/3 long-pitch winding.

[0046]
Next, as shown in Figures 9 and 11C, the conductor wire 24 that extends outward from the slots at Slot Number 4 is wound for two turns into a wave winding in the forward direction in slots including Slot Numbers 10, 13, 16, 19, etc., through 4, and 7 that are arranged at a pitch that that corresponds to an electrical angle of n. Then, as shown in Figure 11D, the conductor wire 24 that extends outward from the slots at Slot Number 7 is wound for one turn into a wave winding in the reverse direction in slots including Slot Numbers 4, 1, 34, 31, etc., through 10, and 7 to produce the Zl winding portion 48. This Zl winding portion 48 is a three-turn wave winding that is configured by winding the conductor wire 24 into full-pitch windings in a slot group that is constituted by the slots at Slot Numbers 10, 13, 16, 19, etc., through 4, and 7.

[0047]
Thus, as shown in Figure HE, the Z phase winding 47, in which the Zl winding portion 48 and the Z2 winding portion 49 are connected in series, is made of a single conductor wire 24. Two ends of the Z phase winding 47 extend outward from the slots at Slot Numbers 9 and 7.

[0048]
Next, as shown in Figures 9 and 12A, the conductor wire 24 that extends outward from the slots at Slot Number 7 is wound for two turns into a wave winding in the reverse direction in slots including Slot Numbers 5, 2, 35, 32, etc., through 11, and 8 that are arranged at a pitch that that corresponds to an electrical angle of n. Then, as shown in Figure 12B, the conductor wire 24 that extends outward from the slots at Slot Number 8 is wound for one turn into a wave winding in the forward direction in slots including Slot Numbers 5, 8, 11, 14, etc., through 35, and 2 to produce the Yl winding portion 45. This Yl winding portion 45 is a three-turn wave winding that is configured by winding the conductor wire 24 into full-pitch windings in a slot group that is constituted by the slots at Slot Numbers 2, 5, 8, etc., through 32, and 35.

[0049]
Next, as shown in Figures 9 and 12C, the Y21 winding portion 46a is formed by winding the single conductor wire 24 that extends outward from the slots at Slot Number 2 for three turns into a wave winding in the forward direction in slots including Slot Numbers 4, 8, 10, 14, etc., through 34, and 2 that are arranged so as to alternately occupy intervals that correspond to electrical angles of 2n/3 and 4n/3. Next, as shown in Figures 9 and 12D, the Y22 winding portion 46b is formed by winding the conductor wire 24 that extends outward from the slots at Slot Number 2 for three turns into a wave winding in the forward direction in slots including Slot Numbers 1, 5, 7, 11, etc., through 31, and 35 that are arranged so as to alternately occupy intervals that correspond to electrical angles of 2n/3 and 4n/3. The Y2 winding portion 46, in which the Y21 winding portion 46a and the Y22 winding portion 46b are connected in series, is configured thereby. This Y2 winding portion 46 is a six-turn wave winding that is configured by winding the conductor wire 24 so as to alternate repeatedly between a 2n/3 short-pitch winding and a 4n/3 long-pitch winding.

[0050]
Thus, as shown in Figure 12E, the Y phase winding 44, in which the Yl winding portion 45 and the Y2 winding portion 46 are connected in series, is made of a single conductor wire 24. Two ends of the Y phase winding 44 extend outward from the slots at Slot Numbers 5 and 35.

[0051]
Thus, the Y phase winding 44 and the Z phase winding 47 are formed by a single conductor wire 24. A portion of the conductor wire 24 that extends outward from the slots at Slot Number 7 and enters the slots at Slot Number 5 becomes a crossover portion 50 that connects the Y phase winding 44 and the Z phase winding 47.

The insulating coating of the crossover portion 50 is peeled off, and the end portion of the X phase winding 41 that extends outward from the slots at Slot Number 9 is connected to the crossover portion 50 from which the insulating coating is removed. The X phase winding 41, the Y phase winding 44, and the Z phase winding 47 are thereby wye-connected to form the stator winding 40.

[0052]
Now, the slot groups into which the conductor wires 24 of the XI winding portion 42, the X2 winding portion 43, the Yl winding portion 45, the Y2 winding portion 46, the Zl winding portion 48, and the Z2 winding portion 49 are mounted are identical to the slot groups into which the conductor wires of the XI winding portion 26, the X2 winding portion 27, the Yl winding portion 29, the Y2 winding portion 30, the Zl winding portion 32, and the Z2 winding portion 33, respectively, are mounted in Embodiment 1.

Consequently, the stator winding 40 that is configured in this manner forms an equivalent electrical circuit to the stator winding 22 according to Embodiment 1. The phase difference 0 between the XI winding portion 42 and the X2 winding portion 43 is n/6, the phase difference 0 between the Yl winding portion 45 and the Y2 winding portion 46 is n/6, and the phase difference 0 between the Zl winding portion 48 and the Z2 winding portion 49 is n/6.

[0053]
Consequently, similar effects to those in Embodiment 1 above can also be achieved in Embodiment 2.

According to Embodiment 2, because the X phase winding 41 is formed using a single conductor wire 24, and the Y phase winding 44 and the Z phase winding 47 are formed using a single conductor wire 24, the connection point for forming the stator winding 40 is a single position, facilitating the manufacturing of the stator winding 40.

[0054]
Moreover, in each of the above embodiments, the stator windings are configured by wye-connecting an X phase winding, a Y phase winding, and a Z phase winding, but the alternating-current connection that connects the X phase winding, the Y phase winding, and the Z phase winding is not limited to a wye connection, and may also be a delta connection, for example.

WE CLAIM:

1. An automotive alternator comprising:

a rotor (8) that is rotatably supported by a housing (4); and a stator (20) comprising-'

a cylindrical stator core (21) in which slots are formed at a ratio of one slot per phase per pole; and

a stator winding (22, 40) that is configured by alternating-current connecting three phase windings (25, 28, 31, 41, 44, 47) that are mounted into said stator core (21),

said stator (20) being supported by said housing (4) so as to surround said rotor (8), said automotive alternator being characterized in that: each of said phase windings (25, 28, 31, 41, 44, 47) is configured by connecting in series a first winding portion (26, 29, 32, 42, 45, 48) and a second winding portion (27, 30, 33, 43, 46, 49) that have a phase difference that corresponds to an electrical angle of n/6 from each other;

said first winding portion (26, 29, 32, 42, 45, 48) is configured by winding a conductor wire into a full-pitch winding;

said second winding portion (27, 30, 33, 43, 46, 49) is configured by winding a conductor wire so as to alternate repeatedly between a 2n/3 short-pitch winding and a 4n/3 long-pitch winding; and

a turn ratio between said first winding portion (26, 29, 32, 42, 45, 48) and said second winding portion (27, 30, 33, 43, 46, 49) is 1:2.

2. An automotive alternator according to Claim 1, characterized in that two phase windings (44, 47) among said three phase windings (41, 44, 47) are configured by winding a single conductor wire continuously, and a remaining single phase winding (41) is configured by winding a single conductor wire continuously.