JPH07107704A - Ac generator for vehicle - Google Patents

Abstract

PURPOSE:To disperse the degree components of an air sound, and to reduce the dispersion of the components of various orders of the air sound by forming the shell shape of an intake hole in a non-circular shape. CONSTITUTION:A shell shape on a bracket end face of an intake hole 1A formed to the end face of a front-side bracket 1 for a three-phase AC motor for a car is formed in a quadrangle. Consequently, the distribution of the degree of an air sound is dispersed as compared with the case of a circular shape when the shell shape of the intake hole 1A is formed in the quadrangle, thus reducing the air sound. Likewise, the same effect is also obtained in the intake hole of a rear-side bracket. The same effect is also acquired when the shell shape of the intake hole 1A is formed in a polygon except the multiple of three such as a pentagon, a heptagon, an octagon, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alternator used in engines of vehicles such as automobiles.

[0002]

2. Description of the Related Art FIG. 5 is an axial cross-sectional view showing a conventional three-phase AC vehicle alternator disclosed in, for example, Japanese Patent Laid-Open No. 3-7039, and FIG. 6 is a diagram of FIG. 5 viewed from the right.

In the drawing, 1 is a front bracket,
2 is a rear bracket, 3 is a stator, and a stator core 3a
And a stator coil 3b wound around it. Reference numerals 1a and 2a denote intake holes provided on the end faces of the brackets 1 and 2, respectively, and a shape (hereinafter, referred to as an outer shape) surrounding the intake holes 1a or 2a has a circular shape (hatched portion in FIG. 6). ing. Similarly, exhaust holes 1b and 2b are respectively provided on the outer peripheral portions of both brackets 1 and 2, and 4 is fitted with the opening edges of both brackets 1 and 2 to both ends of the outer periphery of stator iron core 3a to fix stator iron core 3a. Bolts 5 for sandwiching and fixing are shafts, and are rotatably supported via bearings 6 and 7 supported by both brackets 1 and 2. Reference numerals 8 and 9 denote magnetic pole cores fixed to the shaft 5 and positioned inside the stator 3, 10 denotes an exciting coil sandwiched between the inner circumferences of the magnetic pole cores 8 and 9, and 11 and 12 denote magnetic pole cores 8 and 9, respectively. A pair of fans fixed to the end faces and rotating with the rotation of the shaft 5, 13 is a slip ring attached to the shaft 5, 14 is the shaft 5, the magnetic pole cores 8 and 9, the exciting coil 10, the fans 11 and 12, and the slip rings. Thirteen
It is a rotor composed of and.

Reference numeral 15 is a current collector for power supply which accommodates a brush 15a which is in sliding contact with the slip ring 13, and 16 is supplied with an exciting current from the brush 15a to the exciting coil 10 through the slip ring 13 so that the exciting coil 10 and A rectifier that rectifies the alternating current induced in the stator coil 3b by rotating the magnetic pole cores 8 and 9 via a pulley 17 by an engine (not shown) and converts the alternating current into a direct current 16
a is a heat sink that radiates the heat generated by the rectifier 16, 18 is a voltage regulator that detects the generator voltage and controls the exciting current to adjust the terminal voltage, and 18a is the voltage regulator 1
8 heat sink.

Next, the operation of the conventional AC generator will be described. As the fans 11 and 12 rotate, cooling air flows in from the intake hole 1a of the front bracket 1 as shown by the arrow 19, and the bearing 6, the magnetic pole core 8, the exciting coil 10, the stator core 3a and the stator coil 3b. Is discharged to the outside through the exhaust hole 1b. Similarly, the cooling air flows in from the intake hole 2a of the rear bracket 2 as shown by the arrow 20, and the bearing 7, the voltage regulator 18, the rectifier 16, the magnetic pole core 9, the exciting coil 10, the stator core 3 are provided.
a, the stator coil 3b is cooled, and is discharged to the outside through the exhaust hole 2b.

[0006]

In the conventional vehicular AC generator, as shown in FIG. 6, since the outer shape of the intake hole 1a is circular, the order dispersion of wind noise is not sufficient, which is why As shown in FIG. 7, there is a problem in that the sound pressure of a specific order, for example, 6th order, 12th order, etc. becomes high and an unpleasant sound is generated. In addition, in other conventional different generators, since the outer shape of the intake hole is circular, the order dispersion of wind noise is not sufficient, and as shown in FIG. However, there is a problem that the sound pressure of is increased and an unpleasant sound is generated.

The present invention has been made in order to solve such a problem, and a vehicle in which the outer shape of the intake hole is made non-circular to disperse the order component of the wind noise and to reduce the wind noise and hence the unpleasant noise. The purpose is to obtain an AC generator for use.

[0008]

In the vehicular AC generator according to the present invention, the outer shape of the intake hole is a non-circular shape.

[0009]

In the present invention, since the outer shape of the intake hole is a non-circular shape, the order components of the wind noise can be dispersed and the wind noise can be reduced.

[0010]

EXAMPLES Example 1. 1 and 2 showing an embodiment of the present invention.
Will be described. Figure 1 is a view from the end of the bracket,
FIG. 2 is an analysis diagram of wind noise frequencies, and the same or corresponding parts as those of the above-described conventional one are designated by the same reference numerals and the description thereof will be omitted. In the figure, 1A is an intake hole provided on the end surface of the front side bracket 1, and as shown in FIG. 1, the outer shape of the bracket end surface (outer shape of the portion shown by hatching in the figure)
Is a quadrangle. The AC generator has 12 poles, 10 front fan blades, and 14 rear fan blades.

When the outer shape of the intake hole 1A is made quadrangular in this way, as compared with the data of the circular intake hole 1a shown in FIG. 7, the dispersion of the order component of the wind noise is shown in FIG. As a result, wind noise is reduced. In the above description, the intake hole 1a of the front bracket 1 is described, but it goes without saying that the same effect can be obtained in the intake hole 2a of the rear bracket 2 as well.

Example 2. Although the outer shape of the intake hole 1A is a quadrangular shape in the first embodiment, the same effect can be obtained by using a polygon other than a multiple of 3, such as a 5, 7, or 8 polygon.
The reason for avoiding a multiple of 3 such as a triangle is to prevent the sixth, ninth, and twelfth order components from being superposed and becoming higher.

Embodiment 3. In this embodiment, the intake hole 1B having a rhombic outer shape is shown, FIG. 3 is a view seen from the end face of the bracket, and FIG. 4 is an analysis diagram of wind noise frequency.
In this way, if the outer shape of the intake hole 1B is rhombic,
Compared with the data shown in FIG. 8, as shown in FIG.
The order component such as the 12th order is reduced, and the overall sound pressure level is lowered. As in the case of the first embodiment, this embodiment is an example in which the number of poles is 12, the number of blades of the front fan is 10, and the number of blades of the rear fan is 14.

[0014]

As described above, according to the present invention, the outer shape of the intake hole is made into a non-circular shape to disperse the order components of the wind noise, and the wind noise can be reduced and unpleasant noise can be reduced. .

[Brief description of drawings]

FIG. 1 is a view showing a first embodiment of the present invention as seen from an end surface of a bracket.

FIG. 2 is an analysis diagram of wind sound frequencies according to the first embodiment of the present invention.

FIG. 3 is a view showing a third embodiment of the present invention as seen from an end surface of a bracket.

FIG. 4 is an analysis diagram of wind noise frequencies according to the third embodiment of the present invention.

FIG. 5 is an axial sectional view showing a conventional one.

FIG. 6 is a diagram of FIG. 5 viewed from the right.

FIG. 7 is an analysis diagram of wind noise frequencies in a conventional device.

FIG. 8 is an analysis diagram of wind sound frequencies in different conventional ones.

[Explanation of symbols]

 1 Front side bracket 1A, 1B, 2a Intake hole 1b, 2b Exhaust hole 3 Stator 3a Stator core 3b Stator coil 5 Shaft 8,9 Magnetic pole core 10 Excitation coil 11,12 Fan 14 Rotor

Claims (3)

[Claims] 1. A magnetic pole iron core fixed to a shaft and excited by an exciting coil, a stator iron core surrounding the magnetic pole iron core and having a stator coil attached thereto, and a bracket for holding the stator iron core and supporting the shaft. A cooling air intake hole provided on an axial end surface of the bracket, a cooling air exhaust hole provided on an outer peripheral surface of the bracket, and a cooling air intake hole attached to an end surface of the magnetic pole core from the intake hole to the inside of the bracket. A vehicle alternator including a fan for introducing cooling air into the vehicle, wherein the outer shape of the intake hole is a non-circular shape. 2. The vehicle AC generator according to claim 1, wherein the vehicle AC generator is a three-phase AC generator, and the outer shape of the intake hole is a polygonal shape except a multiple of 3. . 3. The vehicle AC generator according to claim 2, wherein the outer shape of the intake hole is a quadrangular shape.