JP3368605B2 - Stator of vehicle alternator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stator for an automotive alternator. 2. Description of the Related Art Along with an increase in vehicle load and a reduction in space for mounting auxiliary equipment, there is an increasing demand for downsizing and high output of an AC generator for a vehicle. One of the hindrance factors for increasing the output of an automotive alternator is the problem of an increase in the temperature of the stator windings. An alternator for a vehicle in which this measure is taken is disclosed in JP-A-3-226251. The stator winding structure of this automotive alternator is shown in FIG. 6 and is generally referred to as (2/3) π short-section lap winding. In this winding structure, the winding is shorter than that of all windings with respect to the magnetic pole pitch, and coils a, b, and c of each of the three phases of the stator coil are provided.
Are overlapped and the overlapping area is reduced and the contact area of the cooling air is increased, so that the temperature rise of the stator coil can be suppressed. However, in the above winding structure, as shown in FIG. 7, the reaction magnetomotive force generated from the stator coil at the time of power generation contains many harmonic components and causes the magnetic noise. Becomes The Fourier development diagram of FIG. 7 is obtained by synthesizing the reaction magnetomotive forces of the three phases. In particular, the second and fourth harmonics having large amplitudes become the 18th-order fluctuations (harmonics in which one period changes with the rotation of the rotor at an electrical angle of (2/3) π (radian)), which is the main component of the magnetic sound. Component. An object of the present invention is to provide a stator of an automotive alternator that can reduce the above-mentioned magnetic noise. In order to achieve the above object, a stator of an automotive alternator according to the present invention is formed by short winding the teeth of a stator core with respect to the magnetic pole pitch of a rotor. A first three-phase connection coil in which three stator coils are connected in a three-phase connection, and the stator coils of the first three-phase connection coil are shifted by π / 3 (radian) in electrical angle with respect to the stator coils, respectively. The three stator coils are wound around the teeth in a short-pitch manner, and a winding structure including the first three-phase connection coil and a second three-phase connection coil connected in the same connection manner is provided. . [0005] The stator of the automotive alternator having the above-described structure has first and second triple windings wound around the teeth of the stator core in a short interval with respect to the magnetic pole pitch of the rotor. Each of the three stator coils of the phase connection coil is connected by an electrical angle of π /
Since the winding structure is shifted by 3 (radian), harmonic components included in the reaction magnetomotive force generated from the stator coil at the time of power generation can be canceled, and the magnetic noise generated at the time of power generation can be reduced. FIG. 1 is a perspective view of a stator according to an embodiment of the present invention; FIG.
Will be described. Six teeth are formed at equal angular intervals per two magnetic pole pitches on the inner periphery of the stator core 5a. The stator coil 6a is wound around two adjacent teeth 35a and 35b in an overlapping manner, and then wound around the teeth 35g and 35h that jump over the four teeth 35c to 35f following the tooth 35b. Further, the stator coil 6b includes two teeth 35c, 35c.
d, and then wrapped around the four teeth 35e-3
It is wound around the teeth 35i and 35j that have jumped over 5h. Similarly, the stator coil 6c has two teeth 3
5e, 35f, and two teeth 35k, 3 jumping over four teeth 35g-35j after being wound around.
Wound around 5 l. Then, the above-described winding pattern is sequentially repeated to obtain three stator coils 6a, 6b and 6c.
Is wound around the teeth of the stator core 5a. Further, the stator coil 6d is wound around the stator coil 6a by an electrical angle of π / 3 (radian), that is, one tooth, in the winding direction. After overlapping and winding around two adjacent teeth 35b and 35c, the teeth 35h and 35 jumped over the four teeth 35d to 35g following the tooth 35c.
It is wound around i. The stator coils 6e and 6f are also deflected by π / 3 (radian) in electrical angle with respect to the stator coils 6b and 6c in the winding direction by an amount corresponding to one tooth 35, respectively. The coils are sequentially wound around the teeth of the stator core 5a in a similar winding pattern. Then, as shown in FIG. 3, the stator coils 6a, 6b and 6c are connected to the rectifier 22 as a first three-phase connection coil by performing Y connection. The stator coil 6
Similarly, d, 6e and 6f are Y-connected to form a second three-phase connection coil, which is connected to the rectifier 23. The structure of the automotive alternator incorporating the stator 5 constructed as described above will be described with reference to FIG. The drive frame 1, which forms the outer shell of the vehicle alternator, has a substantially bowl-like shape, and the opening on the rear end side is provided with a cooling air vent 2
Aluminum die-cast rear end frame 3
Are connected by fastening means such as end frame connecting bolts 4 or the like. The stator 5 is incorporated and fixed inside the drive frame 1 by a method such as press fitting. A cylindrical bearing 1a is formed at the center of the side surface of the drive frame 1 on the drive end side.
Is installed. The rear end frame 3
A cylindrical bearing portion 3a is formed in the center of the bearing, and a bearing 8 is attached thereto. The shaft 9 is rotatably supported by these bearings 7 and 8. A pair of pawl-equipped pole cores 10a and 10b are firmly fitted to the shaft 9 so as to be located inside the stator 5, and each pawl is inserted between the other pawls. A coil bobbin 12 around which a field winding 11 is wound is provided at the center of the pole cores 10a and 10b.
Are externally fitted and fixed. The shaft 9 and the pole core 1
0a, 10b and the coil bobbin 12, etc.
Is configured. Cooling fans 14a and 14b are mounted on the side end surfaces of the pole cores 10a and 10b adjacent to the side surfaces of the drive frame 1 and the rear end frame 3, respectively. A plurality of air inlets 15a and air outlets 15b are formed on the drive end side of the drive frame 1, and a plurality of air outlets 15c are formed on the rear end side. A pulley 16 is fastened to an end on the drive end side of the shaft 9 by a nut 17.
Tell On the rear end side of the other end of the shaft 9,
A slip ring 18 is fitted on the outside of the rear end frame 3. A brush holder 20 that slides on the slip ring 18 and holds a brush 19 that supplies an exciting current to the field winding 11 therein is provided. A rectifier 22, 2 is provided between the rear end frame 3 and a rear end cover 21 that covers the rear end frame 3.
The rectifier 24 provided with 3 is mounted. The rear end cover 21 has a plurality of air inlets 25 for taking in cooling air and a ventilation hole 26 for passing cooling air to the rectifier 24. The operation of the automotive alternator in which the winding structure of the stator 5 is as described above will be described. When current is supplied to the field winding 11 via the brush 19 and the slip ring 18 and the shaft 9 is rotated by the engine (not shown) via the pulley 16 to rotate the rotor 13, the first three-phase connection coil Three-phase alternating current is induced in the stator coils 6a to 6c and the stator coils 6d to 6f of the second three-phase connection coil. The induced AC current is rectified by the rectifiers 22 and 23 of the rectifier 24 and output to the load, and further charges the battery. Further, the cooling fans 14a and 14b rotate with the rotation of the shaft 9, and on the drive end side of the drive frame 1, cooling air flows from the air inlet 15a to the air outlet 15b by the cooling fan 14a.
Further, cooling air is forcibly taken in from the air introduction port 25 and the ventilation port 26 formed in the rear end cover 21 by the cooling fan 14b. The air taken in from the air inlet 25 generates cooling air discharged from the air outlet 15c through the ventilation port 2 of the rear end frame 3 to cool the stator 5, the pole cores 10a, 10b, and the like. According to the automotive alternator incorporating the stator 5 having the above-described winding structure, the second and fourth large amplitudes included in the reaction magnetomotive force generated from the stator coil during power generation.
It is possible to cancel out the harmonic whose harmonic is the 18th rotation fluctuation with respect to the rotation of the rotor 13, and (2/3) π shown in FIG.
As shown in FIG. 5, the noise level due to the generation of magnetic sound can be significantly reduced as compared with the case of the conventional winding structure called short-section lap winding.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of a main part of a stator. FIG. 2 is an explanatory diagram showing a winding structure. FIG. 3 is an explanatory diagram showing connection of stator coils. FIG. 4 is a side view of the vehicle alternator, showing the upper half and a part of the rear side in cross section. FIG. 5 is a characteristic diagram showing a relationship between a noise level and a rotation speed of a generator. FIG. 6 is a front view of a main part of a stator showing a conventional winding structure. FIG. 7 is a development diagram of a conventional reaction magnetomotive force Fourier. [Description of References] 5 ... Stator 5a ... Stator cores 6a to 6c ... Stator coil (first three-phase connection coil) 6d to 6f ... Stator coil (second three-phase connection) 13) Rotors 35a, 35b, 35c ... teeth

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02K 3/28 H02K 19/22

Claims (1)

(57) [Claims 1] A first three-phase connection coil in which three stator coils wound in short pitches around teeth of a stator core are connected in three-phase with respect to the magnetic pole pitch of the rotor. And an electrical angle of π / with respect to each of the stator coils of the first three-phase connection coil.
A winding composed of three stator coils wound shortly on the teeth, shifted by 3 (radians), and a second three-phase connection coil connected in the same connection mode as the first three-phase connection coil. A stator for a vehicular alternator having a wire structure.