JP2000069714A - Ac generator for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the rib of a cooling window provided in the tubular housing of an AC generator for a vehicle so that the cooling wind may pass easily and that it may reduce noise. SOLUTION: A cooling window W is made in a tubular housing 11, and it is demarcated into individual windows by ribs 12. Stators 4 and 3, rotors 7 and 6, etc., and blow fans 8 and 9 to be cooled are arranged within the cooling window W. The discharge wind having cooled the interior by the cooling fans 8 and 9 is discharged to the outside from the cooling window W, namely, along the smooth flank 12a of the rib 12. The smooth flank 12a of the rib 12 is convex, with its center in thickness direction from inside the rib 12 to outside bulged, so the fluid resistance that the discharge wind receives, etc., becomes small by the rib 12, and the favorable cooling capacity and the reduction of noise level can be contrived.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alternator for a vehicle, and more particularly, to an improved alternator for defining a cooling window formed in a housing of the alternator.

[0002]

2. Description of the Related Art Japanese Patent Laying-Open No. 7-079543 discloses a vehicle alternator characterized by a cooling window structure opened in a housing constituting the generator. As shown in FIG. 10, this generator has a plurality of cooling windows W in a circumferential direction, a cylindrical housing 1 in which a rib 2 is formed between adjacent cooling windows W, and an electronic device fixed in the housing 1. A stator consisting of a coil 4 and an armature core 3, a rotor composed of a Landel-type field core 6 and a field coil 7 held on a rotating shaft 5 supported by the housing 1, A blower fan 8 positioned on the end face side and fixed to the rotating shaft 5 and blowing air from the inside of the housing 1 to the outside toward the cooling window W;
9 is a vehicle alternator.

In this generator, as shown in FIG. 11, the inclination angle θ (θ1, θ2...) Of the rib 2 with respect to the centripetal direction is set large near the front end a in the rotation direction of the support portion 10, and 10 is reduced near the rear end b in the rotation direction. Then, the circumferential width H of the cooling window W (H1, H
2 ...) are narrow in the vicinity of the support portion 10 and the support portion 10
It is set wide at a distance between them. Further, the length of the cooling window W in the centripetal direction is gradually formed from the vicinity of the support portion 10 to the intermediate region of the support portion. That is, when the cooling air protrudes from the housing 1, the flow path resistance of the support portion 10 is made smaller.

[0004]

However, FIG.
As shown in the figure, the cross section of the rib 2 in the conventional generator is
Because of die-cutting or the like, the end portion having a large flow path resistance has a rectangular shape or the like with a corner. Therefore, the cooling air tends to be a vortex or a turbulent flow which causes noise and noise, which hinders the improvement of the cooling air flow.

In recent years, there has been a demand for downsizing of generators due to an increase in the number of parts associated with stricter exhaust gas regulations and higher output and a more compact engine room. The downsizing of the generator is not preferable in terms of its cooling effect, and if the cooling effect is not improved, the power generation capacity is reduced. or,
As described above, since the excess space in the engine room is small, the ambient temperature is also increased, which is disadvantageous in cooling the generator. In addition, power consumption due to the increase in electric accessories has also increased. For this reason, there is a strong demand for further improvement in cooling performance and accompanying improvement in power generation capacity.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides an AC generator for a vehicle which further improves the power generation capacity by further improving the cooling effect and reduces noise.

[0007]

SUMMARY OF THE INVENTION The inventor of the present invention has disclosed that cooling air blown from a cooling fan of a vehicle alternator passes through a rib defining a cooling window located at an end of a cylindrical housing. In doing so, they paid attention to the fact that they had the greatest hindrance and had a negative effect on the noise generation and cooling effect during passage, and came to the idea of forming the ribs into a shape with less fluid resistance.

[0008] That is, the automotive alternator of the present invention has a plurality of cooling windows in the circumferential direction, a cylindrical housing having a rib between adjacent cooling windows, and a stator fixed in the housing. A rotor rotatably held by the housing, and a blower fan fixed to an end face of the rotor and blowing air from the inside of the housing toward the outside toward the cooling window to partition the cooling window. The ribs are characterized in that the side surfaces of the ribs are convex at the center in the thickness direction from the inside to the outside of the ribs.

In the vehicle alternator according to the present invention, it is preferable that the convex surface on the side surface of the rib is a convex curved surface.
In the vehicle alternator according to the present invention, it is preferable that a cross section of the rib is circular, elliptical, or streamlined. In the vehicle alternator according to the present invention, the housing may have a dome shape in which an outer peripheral diameter decreases as one end of the housing approaches the end, and the rib may be located at the one end of the dome. .

In the AC generator for a vehicle according to the present invention, the housing is formed by die-cutting with a mold having an outer peripheral type defining an outer peripheral surface and an inner peripheral type defining an inner peripheral surface. It is preferable that the parting line of the inner circumference and the inner circumference be a line connecting the tops of the convex surfaces.

[0011]

In the vehicle alternator according to the present invention, the discharge air flowing from the inside to the outside of the cooling window opened in the housing flows along the side surface of the rib. The rib of the present invention
Since the central portion of the side surface along the flow is a convex surface, the fluid resistance at the rib head is small, and behind the central portion, the pressure on the rear surface of the rib side surface is small, and the flow of discharge wind And the cooling efficiency can be increased. Further, since the flow of the discharge air is smooth, noise can be reduced.

By making the side surfaces of the ribs convex, the flow of the discharge air becomes smoother. By making the cross section of the rib circular, elliptical, or streamlined, the flow of the discharge air is also smooth. The housing has a dome shape whose outer diameter decreases as one end of the housing approaches the end, and the ribs are located at the one end of the dome so that air in the housing is easily discharged.

The housing is formed by die-cutting with a die having an outer peripheral die defining an outer peripheral surface and an inner peripheral die defining an inner peripheral surface. By forming a line connecting the tops of the convex surfaces, even in the case where the center part of the side surface has a rib having a convex surface, it is punched out in the axial direction with a split mold of an outer peripheral type and an inner peripheral type of a cylindrical housing,
A rib having a convex surface at the center can be easily formed.

That is, the housing is manufactured by molding, but in order to form a rib having a convex surface at the center of the side surface as in the case of the cooling window of the present invention, taking into account die-cutting,
The rib cross-sectional shape was restricted. In particular, since a cylindrical housing requires die cutting in the axial direction, the cross-sectional shape of the rib that defines the cooling window has a shape corresponding to die cutting in the axial direction. It had to be shaped.

[0015] For this reason, a vortex which causes noise or the like is easily generated in the flow of the discharge wind, which causes noise and a decrease in air volume. Therefore, in the case where the ribs of the present invention in which the eddy current is reduced and the noise and the air volume are prevented from being reduced are formed by the inner peripheral die and the outer peripheral die for forming the cylindrical housing, the outer peripheral die and the inner peripheral die are divided. Is made coincident with the line connecting the tops of the convex surfaces, the mold can be removed simply by removing the inner peripheral die and the outer peripheral die in the axial direction, and the production becomes easy.

The side surfaces of the rib defining the cooling window are present on both sides, and the convex surface in which the central portion in the thickness direction from the inside to the outside of the rib is a convex surface is restricted by manufacturing restrictions. For one side only.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) As shown in FIG. 1, a vehicle alternator according to the present invention has a rib for partitioning a cooling window W located at an end of a cylindrical housing 11 constituting the generator. 12
Except for the above, the configuration is the same as that of the related art, and the same reference numerals are given.

That is, the vehicle alternator of the present invention comprises:
A rotor composed of a rundle type field iron core 6 and a field coil 7 is held on a rotating shaft 2 supported by a housing 11, and an armature field iron core 3 and an armature coil 4 are provided on the inner peripheral surface of the housing 11. Is fixed so as to surround the rotor. The housing 11 includes a cylindrical front housing 11a and a cylindrical rear housing 11b fastened by the support portions 10.
1b, a cover 13 is mounted on the rear end face.
3 and the rear housing 11b form an electric component room S containing a rectifier, a brush or a regulator.

With the above basic configuration, when the rotating shaft 5 is driven by the rotation of the engine and the field coil 7 is energized and excited, the three-phase AC voltage generated in the armature coil 4 is rectified by the rectifier. Output. The configuration of the characteristic portion of the present invention is the ribs 12 of the cooling window W provided in the front housing 11a or the rear housing 11b in a large number in the circumferential direction. The cooling window W allows the cooling air to flow from the inside of the housing 1 to the outside along a smooth side surface 12 a of the rib 12, which will be described later.

In the following description, the front housing 11
A description will be given by taking the rib 12 of the cooling window W formed at a as an example. However, a similar cooling window W is provided in the rear housing 11b.
In addition, a rib 12 for partitioning the cooling window W may be formed.
FIGS. 2 to 4 show one rib 12 which is enlarged in the circle of FIG.
FIG. The front housing 11a on which the ribs 12 are formed has a cylindrical shape at the peripheral side and a dome-shaped end at the end. The rib 12 is formed at an end of the front housing 11a, and has a smooth side surface 12 suitable for air flow as follows.

As shown in FIG. 3, the rib 12 has a cross section at the boundary position (position AA in FIG. 2) with the peripheral side of the front housing 11a. The surfaces are substantially the same, and the outer side is a tapered portion 120 narrowed toward the outer diameter region. As shown in FIG. 4, the rib 12 has a small-diameter inner arc-shaped portion 121 at a portion where the front housing 11a starts to bend toward the inner diameter side (a position taken along line BB in FIG. 2). A similar tapered portion 122 is connected to the outer diameter region.

Further, the rib 12 is provided on the front housing 1.
1a is near the end portion where it has been bent toward the inner diameter side (CC in FIG. 2).
As shown in FIG. 5, the cross-sectional shape at (line position) is a combination of a large-diameter inner arc-shaped portion 123 and a tapered portion 124 similar to FIG. . To summarize the rib shape, on the side surface of the rib 12,
Arc-shaped portions 121 and 123 and tapered portions 120 and 122
And 124 are formed, and the central ridge portion is a convex portion having a maximum thickness at a central portion from the inside to the outside of the rib 12. Further, the side surface of the rib 12 forms a smooth convex curved surface along the discharge air flow direction D by a spherical surface formed by the arc portions 121 and 123 and a curved surface formed by the tapered portions 120, 122 and 124. Present.

By the way, inside the cooling window W defined by the ribs 12 having the above-mentioned shape, cooling fans 8, 9 located on the end face of the field core 9 and fixed to the rotating shaft 5 are provided.
According to the automotive alternator having the ribs 12 of the cooling window W, the outside air is sucked by the cooling fan 8 from the opening 13 (FIG. 1) in front of the housing 1, and the outside air is discharged from the cooling window W as discharge air. When releasing to the outside, the rotor and the stator are cooled.

The discharge air passing through the cooling window W flows as shown by arrow D in FIG. Due to the cross-sectional shapes of the ribs 12 shown in FIGS. 3 to 5, the flow of the discharged air is smoother and faster than in the case of a blunt head such as a rectangle. Therefore, the cooling efficiency is improved, and the problem of noise can be reduced. FIG. 6 shows the result of measuring the noise level. As a measurement environment, the generator was placed in an anechoic room, and a microphone was installed at a position 45 to 30 cm behind the rear end of the generator to measure a noise level under no load. The dotted line shows the characteristic in the case of a conventional rib having a rectangular cross section, and the solid line shows the characteristic in the case of the rib shape of the first embodiment. As is clear from this characteristic diagram, the noise level is particularly improved in the high rotation range where the air volume increases.

As described above, the smooth flow of the discharge air is caused by the leading spherical portion formed by the arc portions 121 and 123 and the tail portion of the curved surface formed by the tapered portions 120, 122 and 124. The effect is based on The longer the tail is, the better the streamline is, so that the flow of the discharge air can be further smoothed. By the way, the front housing 11a can be easily formed by cutting an outer peripheral die for defining the outer peripheral surface and an inner peripheral die for defining the inner peripheral surface in the axial direction E (FIG. 2).

That is, the rib 12 may be formed such that the central ridge line G where the arc-shaped portions 121 and 123 and the tapered portions 120, 122 and 124 are joined is a parting line. Central ridge line G
Consists of a straight line 14 parallel to the axial direction E and a curved line 15 at the dome-shaped end. Intersection point P between straight line 14 and curve 15
Corresponds to the inner peripheral surface position of the peripheral side portion of the front housing 11a. Therefore, the arc-shaped portions 121 and 123 are of the inner circumference type.
And the outer peripheral mold is used to form the tapered portions 120, 122, 12
By molding 4, both molds can be removed in the axial direction E.

The first embodiment is suitable for the case where the cooling window W cannot be elongated in the axial direction. (Second Embodiment) In a second embodiment of the present invention, as shown in FIG. 8, the cooling window W is long in the axial direction, and the rib 16 is also large in the axial direction. Thus, the rib 16 having a long axial portion
Cannot be made spherical by the arc-shaped portion 121 as in the first embodiment. This is because if the outer peripheral surface of the inner peripheral mold is divided by a circumferential surface, a connecting portion between the spherical surface and the circumferential surface is formed, and the axial portion is interrupted.

Therefore, as shown in FIGS. 7 and 9, the rib 16 of this embodiment has a concave arcuate surface 161 opposite to the inner peripheral outer peripheral cylindrical surface 18 (the inner peripheral surface of the front housing 11a). An arc-shaped portion 162 on the front surface, a tapered portion 163 similar to that of the first embodiment, and an arc-shaped portion 162 'connected to the front housing 11a at an axial end position. The rib 16 shown in FIG. 9 shows a cross-sectional shape at the position of line FF in FIG.

With the rib 16 having the above-described structure, a smooth flow of the discharge air and a reduction in noise can be expected as in the first embodiment. In particular, in the case of this embodiment, the tapered portion 16
3 may be lengthened. Also, the center ridge line G of the rib 16
Can be a straight line in the axial direction, and the die can be removed in the axial direction by aligning the parting line with the inner wall surface of the front housing 11a.

The ribs 12 and 16 include relatively thin ribs for defining the cooling window W and, for example, four support ribs provided for fixing the front housing 11a and the rear housing 11b with bolts. 1. It can be formed by the second embodiment. In the second embodiment, the leading arc surface 161 may be flat.

[Brief description of the drawings]

FIG. 1 is a sectional view of an automotive alternator according to a first embodiment. It is a side view of the rib which divides the cooling window located in the edge part of a housing.

FIG. 2 is an explanatory view illustrating a shape of a rib by enlarging a cooling window in a circle in FIG. 1;

FIG. 3 is a sectional view of a rib taken along a line AA in FIG. 2;

FIG. 4 is a cross-sectional view of a rib taken along a line BB in FIG. 2;

FIG. 5 is a cross-sectional view of a rib taken along a line CC in FIG. 2;

FIG. 6 is a characteristic diagram showing a measurement result of a noise level comparing the present invention with a conventional product.

FIG. 7 is an explanatory diagram illustrating the shape of a rib according to a second embodiment.

FIG. 8 is a front view of the generator according to the second embodiment, centered on ribs, as viewed from the front side.

FIG. 9 is a cross-sectional view of a rib taken along a line FF in FIG. 8;

FIG. 10 is a sectional view showing a conventional vehicle alternator.

FIG. 11 is an explanatory diagram illustrating characteristics of a conventional rib.

FIG. 12 is an explanatory diagram illustrating the operation of a conventional rib.

[Explanation of symbols]

W: cooling window, 8, 9: blower fan, 11: housing,
11a front housing, 11b rear housing, 12, 16 rib, 12a rib side surface, 120,
122, 124: tapered portion, 121, 123: arc portion, 14, 15: parting line, G: central portion (central ridge line).

Claims (5)

[Claims] 1. A cylindrical housing having a plurality of cooling windows in a circumferential direction and having a rib between adjacent cooling windows, a stator fixed in the housing, and rotatably held by the housing. A rotor, and a blower fan fixed to an end face of the rotor and blowing air from inside to outside of the housing toward the cooling window, wherein the rib defining the cooling window is provided. The alternator for a vehicle, characterized in that a side surface of the rib is a convex surface in which a central portion in the thickness direction from the inside to the outside of the rib is convex. 2. The alternator for a vehicle according to claim 1, wherein the convex surface on the side surface of the rib is a convex curved surface. 3. The alternator according to claim 2, wherein the cross section of the rib is circular, elliptical, or streamlined. 4. The alternating current for a vehicle according to claim 1, wherein the housing has a dome shape in which an outer peripheral diameter decreases as one end of the housing approaches the end, and the rib is located at the one end of the dome. Generator. 5. The housing is formed by die-cutting with a mold having an outer peripheral die for defining an outer peripheral surface thereof and an inner peripheral die for defining an inner peripheral surface thereof. 5. The alternator for a vehicle according to claim 4, wherein a line is a line connecting the tops of the convex surfaces.