JPH03226251A - Ac generator for vehicle - Google Patents

Abstract

PURPOSE:To improve cooling efficiency by a method wherein three pieces of tees are arranged annularly with equal intervals on the inner periphery of a stator core in the circumferential direction per two pitches of magnetic poles of a rotor coil while one phase of stator coil is wound around respective tees. CONSTITUTION:Three pieces of tees 41a, 41b, 41c are arranged annularly with equal intervals on the inner peripheral surface of a stator core 15 in a circumferential direction per two poles 18, 19 of the pole core of a rotor. The stator coil 16(x, y, z) for one phase is wound around respective tees 41a-41c. According to this method, the number of tees of the stator coil for the same magnetic pole number is reduced to a half, noise due to magnetic sound is reduced, the overlap of the coils of respective phases is reduced and the contacting area of cooling air is increased whereby cooling effect is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an alternator for a vehicle, and particularly to a stator coil winding structure for an alternator for a vehicle.

(Prior Art) Vehicle alternators have traditionally been required to have higher output and be smaller in size as the use of vehicle electrical devices and electrical control devices increases and installation space is saved.

Conventional AC generators have been designed to improve cooling efficiency as a means of increasing the output of the alternator. It is known that the cooling efficiency is improved by arranging a cooling fan to face the gap and using the gap as a ventilation path.

(Problem to be Solved by the Invention) However, according to the conventional stator coil winding structure of a vehicle alternator, each of the three-phase coils is Since the phase coils are wound around each of the three teeth of the stator core, the coils of each phase of the three-phase coil overlap, increasing the amount of overlap between the coils. There is a problem that the length increases, the amount of heat generated increases, and the thermal efficiency decreases.

For example, as shown in FIGS. 8 and 9, in the conventional system, a stator 2 is fixed to the inner peripheral wall of a cylindrical frame 1.
Thirty-two teeth 3 having a T-shaped cross section are arranged in an annular manner, and each tooth 3 extends in the axial direction and protrudes radially inward, and each of the coils x, y, z of the X phase, Y phase, and Z phase are wound around three teeth 3 as one unit, and the coils x, y, and Z are wound around the teeth 3 in the winding order of X phase, Y phase, and 2 phases. In any of the winding methods, since the coils x, y, and z have a wrap margin that covers each other at both the axial front end and the axial rear end of the teeth 3, the coil length is extended and the coil The exposed area was reduced, the contact area with the outside air was reduced, and the cooling effect was insufficient. The present invention was made to solve these problems, and it A vehicle alternator that uses a winding structure that reduces the overlap winding allowance of the coil, increasing the exposed surface of the stator coil and increasing the contact area with the outside air, increasing cooling efficiency and achieving high output. The purpose is to provide

(Means for Solving the Problems) To achieve this, the vehicle alternator of the present invention includes a rotatable rotor, a ball core fixed to the rotor, a ball core wound around the ball core, and excited by an exciting current. a stator core fixed at an outer peripheral position facing the rotor coil; a three-phase stator coil wound around the stator core with different phases; The alternator for a vehicle is equipped with an inner fan-type cooling fan for cooling.

On the inner periphery of the stator core, three teeth are arranged in the circumferential direction for every two magnetic pole pitches of the rotor coil, and each tooth has three teeth.
It is characterized in that only one phase stator coil of the phase stator coils is wound.

(Function) In the vehicle alternator of the present invention, the electrical angle 2π (rad)
Since it has a configuration in which three stator teeth are formed inside, the number of teeth is halved from six to three compared to the conventional one, and the coils of each phase are wound around each individual tooth. Therefore, as can be seen by comparing, for example, Figures 1 and 9, the proportion of overlap between the wound coils of each phase is reduced, and the area exposed to the cooling air around the coils increases, increasing the cooling effect. .

(Example) A first example of the vehicle alternator of the present invention will be described based on FIGS. 1 to 4.

First, the structure of the generator will be explained based on FIG. 3, and then the winding structure of the stator coil will be explained in detail.

In FIG. 3, the inner periphery of the front frame 12 and rear frame 13, which are fixed to each other by bolts 10, etc.
As is well known, a stator 14, which is composed of a stator core 15 and a stator coil 16 wound around the stator core 15, is fixed.

A rotor coil 17 for generating an electromotive force in the stator coil 16 by electromagnetic induction is wound around a metal bobbin and fixed between a pair of ball cores 18 and 19 with claws. A shaft 20, which mechanically fixes the ball core 18.19, is rotatably supported by a bearing 21.22. Cylindrical bearing boxes 23 and 24 to which these bearings 21 and 22 are attached are attached to the central portions of the sides of the front frame 12 and rear frame 13, respectively.

A boulege 5 to which rotational driving force from an engine (not shown) is transmitted is fastened to the front end of the shaft 20 with a nut 26 and a washer 27. Slip rings 31 and 32, which are electrically connected to the rotor coil 17 via a conductor 30, are attached to the rear end of the shaft 20 outside the rear frame 13.

On both sides of the ball core 18.19, cooling fans 34.35 having a diameter smaller than the stator inner diameter are arranged concentrically with the shaft axis, and each fan blade is axially forward of the ball core 18.19. They are fixed facing towards the rear. The cooling fans 34 and 35 have a mixed flow shape that is inclined in the rotor rotation direction so as to form a cooling air passage for cooling the rotor coil 17 and the stator coil 16. A suction window 37 for sucking cooling air into the generator is formed near the bearing 22 and at a position facing the cooling fan 35 . Further, a discharge window 38 is formed in the front frame 12 to discharge hot air after cooling.

Next, FIG. 1 shows the winding state of the stator coil 16.
This will be explained based on FIGS. 2 and 4.

The stator core 15 has an annular shape, and a plurality of teeth 41 having a T-shaped cross section protrude from the inner circumferential side of the stator core 15 at predetermined intervals. The stator coil 16 is wound around the inter-teeth groove formed between these adjacent teeth 41. The three-phase coils x, y of the stator coil 16,
z is wound in mutually different inter-teeth grooves, and in each inter-teeth groove, as shown in FIG. 1(b),
The coils of y, 2.2 and X are divided and distributed and wound in two layers. The number of teeth 41 is three teeth 41a, 41b, 41c for every two magnetic pole pitches formed by the rotor coil inside the ball core 18, 19 facing the radially inner side of the teeth 41, and the total number is as follows. Teeth 41 of three times the number are formed in an annular shape.

The stator coil winding method of this embodiment is a lap winding method, and the winding order of the three-phase coils is as follows. First, as shown in FIG. 2, the X-phase coil The winding is repeated in the same manner with the teeth 41b and 41c spaced apart. After winding the X-phase coil
A Y-phase coil y is wound around 1b, and then the Y-phase coil y is wound in a circular manner in the same manner. After winding the Y-phase coil y, the Z-phase coil Z is wound around the teeth 41C, and then the next adjacent tooth 4 is wound with the two teeth 41a and 41b spaced apart.
A Z-phase coil Z is wound around 1c, and the winding is repeated in the same manner.

The stator coil 16 wound in this way is
As shown in figures (a) and (b), teeth 41a and 41
In the groove between the teeth between teeth 41b and 41c, an X-phase coil
A Y-phase coil y is wound in the deep part of the groove and a Z-phase coil Z is wound in the shallow part of the groove between teeth 41c and 41a.
In the groove between the teeth, an X-phase coil X is wound in the deep part of the groove, and a Z-phase coil Z is wound in the shallow part of the groove in two layers.

The X-phase, Y-phase, and Z-phase coils x, y, and z are wound around the individual teeth 41a, 41b, and 41c by overlapping winding.

According to this stator coil winding structure, as shown in FIG. 4, the winding coil front end 16a of the stator coil 16,
gaps A of unequal size between each of the rear end portions 16b;
B is formed. By forming the gaps A and B, the gaps serve as channels for cooling air to pass through, and the cooling effect increases as the exposed area of the coil for contact with the cooling air formed by the gaps is large.

According to the above configuration, three teeth 4 are arranged at equal intervals on the inner circumference of the stator core 15 between the two magnetic pole pitches of the rotor coil.
1a, 41b, 41c are provided, and these teeth 41a
, 41b, 41c are arranged in an annular shape, and the X-phase, Y-phase, and Z-phase windings are sequentially applied to the grooves between adjacent teeth. Generate electricity. In the case of this stator coil winding structure, the winding! Since the pseudo pitch is 2/3 magnetic pole pitch, compared to the conventional stator coil winding structure with 1 magnetic pole pitch, the resistance value of the entire coil length per l is reduced to 2/3, so the same load current The loss that occurs when flowing 2 is reduced to about 67% due to the relationship of (current ■) 2 (resistance R), the amount of heat generated is reduced, and the rate of temperature rise is reduced.

Furthermore, when comparing the conventional example in the case of this lap winding method and this embodiment based on FIG. 5, it is found that in the present embodiment the coil can be wound sectionwise in the circumferential direction, but in the conventional example With this winding method, mutual lap portions L1 are formed between the X phase, Y phase, and two phases. Therefore, in the present embodiment, since basically no wrap portion of the multi-turn coil occurs, the exposed area ratio of cooling air contact per the entire length of the coil increases, and furthermore,
The cooling effect is improved by applying cooling air to both ends of the stator coils by cooling fans 34 and 35 provided on the radially inner sides of the stator coils x, y, and z.

Furthermore, in this embodiment, as shown in FIG. 1, the ball core 18.19 and the teeth 41a of the stator core 15,
Regarding the gap length between core claw central part 1 and 41b and 41c,
Since both core claw end portions 19b are formed in a concave shape than 9a, the gap length is made larger than the gap length C shown in FIG. occurs, improving the cooling performance of the surfaces of the ball cores 18, 19 and stator core 15, and improving ventilation.As the cooling air passage expands, a cooling air relief effect occurs at the front end and rear end of the coil, and the coil The cooling performance of the front end and rear end is also further improved. Since a cooling air passage having both the above-mentioned gaps A and B and the gap length C1 is formed, the ventilation is improved and the wind wave resistance is greatly improved, so the heat dissipation area is large and the cooling effect is large. . Also, since the sizes of gap A and gap B are unequal,
Bitch noise (monochromatic frequency component wind noise) caused by cooling fan wind pressure is also less likely to occur.

It goes without saying that the present invention can be applied to a stator coil winding structure using a wave winding method instead of the lap winding method.

Regarding a wave-wound coil, for example, as shown in FIG. 6, in a conventional example, a wrap portion L2 is formed at both the front end and the rear end of the coil end. However, in the embodiment of the present invention, the rear end side of the coil is connected to the coils x, y, z of each phase.
Since each tooth is divided and wound, no wrap portion is generated. Therefore, even in the wave-wound embodiment of the present invention, no overlapping portion of the wound coils occurs at the front end of the coil, so that the area exposed to cooling air per average unit length of the coil is increased.

As explained above, according to the generator according to the embodiment of the present invention, cooling is performed effectively by increasing the exposed area of the stator coil, and the same number of turns is possible with the coil having a shorter overall length than before, and furthermore, Since the coil is wound in two layers in the groove between the teeth, the number of coil winding leakage points is halved, so the leakage realitance is halved, and output characteristics with a sharp rise from low to medium to high speeds can be obtained. Furthermore, the area ratio of the inner diameter of the stator facing the iron portion is increased, and the air gap force is increased. Furthermore, since the number of teeth is reduced by half compared to the conventional one, the 36th order of the magnetic sound main component is significantly reduced or becomes a low frequency that is not harsh on the ears.

Furthermore, the magnetic flux pulsation frequency on the magnetic pole surface is halved, and the eddy current loss is reduced to 1/4.

In the embodiment shown in FIG. 3, the cooling fans 34 and 35 are located radially inside the stator coil 16, but instead, as in the embodiment shown in FIG. An internal fan type with a cooling fan 50 provided on the side may also be used. That is, the front cooling fan 50 is fixed to the front end side surface of the ball core 18, and the cooling fan mounting position is inside the front diameter of the stator coil 16, and the fan blade tips 50a are located on the front front side of the stator coil 16 and further radially outside. It is extending. This cooling fan 5
0, the cooling air mainly flows in the direction of arrow E.
Coupled with the stator coil winding structure of the stator coil 16 that has a large cooling air contact area as described above, the cooling effect is further increased. Components that are substantially the same are designated by the same reference numerals, and description thereof will be omitted.

(Effects of the Invention) As explained above, according to the vehicle alternator of the present invention, three teeth are provided in the circumferential direction for every two magnetic pole pitches of the magnetic poles generated by the rotor coil.
The number of teeth in the stator coil is halved for the same number of magnetic poles, and the stator coils of each phase are wound around each individual tooth, which reduces the overlap between the coils of each phase and reduces the amount of overlap between the coils of each phase. This has the effect of increasing the contact area, increasing cooling efficiency, and achieving higher output. Additionally, since the number of teeth in the stator is halved compared to the conventional one, noise due to magnetic sound is reduced, which has the secondary effect of increasing efficiency.

[Brief explanation of drawings]

FIG. 1(a) is a schematic configuration diagram showing a part of the winding state of the stator coil according to the embodiment of the present invention, and FIG. 1(b) is a cross-sectional view of the stator coil wound in the groove between the teeth of the stator core. 2 is a coil winding development diagram showing the state of winding of the stator coil; FIG. 3 is a sectional view showing the alternator; FIG. 4 is a partially expanded appearance of the stator shown in FIG. 1. Figure 5 is an explanatory diagram for comparing and explaining the conventional example using the lap winding method and the example according to the embodiment of the present invention, and Figure 6 shows the conventional example using the wave winding method and the example according to the present invention Explanatory diagram for comparing and explaining the 7th
The figure is a partially cutaway sectional view showing an alternator according to another embodiment of the present invention, FIG. 8 is a front view showing a stator according to a conventional example, and FIG. 9 is an enlarged view of the IX portion shown in FIG. 8. . 4 5 6 7 18, 0 Stator, stator core, stator coil, rotor coil, ... ball core, shaft (rotor), a, 41b, 41c) teeth, X-phase stator coil, Y-phase stator coil, Z-phase stator coil .

Claims (1)

[Claims] (1) A freely rotatable rotor, a ball core fixed to this rotor, a rotor coil wound around this ball core and excited by an exciting current, and a stator core fixed at an outer peripheral position facing this rotor coil. A vehicular alternator comprising: a three-phase stator coil wound around the stator core with different phases; and an inner fan-type cooling fan that rotates in synchronization with the rotor to cool the stator coil. , The teeth are arranged in an annular manner and at equal intervals on the inner periphery of the stator core so that three teeth are provided in the circumferential direction for every two magnetic pole pitches of the rotor coil, and each tooth has one of the three-phase stator coils. An alternator for a vehicle, characterized in that only a one-phase stator coil is wound.