JPH04183244A - Alternator for vehicle - Google Patents

Abstract

PURPOSE:To suppress noise of vehicle by forming at least one blade of a cooling fan, disposed on the end face of a rotor and provided with many blades on the periphery thereof, in different size from other blades thereby suppressing interferential noise between the blades of the cooling fan and the inner wall of frame body. CONSTITUTION:Centrifugal blades 31b, 31c have height L2, from the bottom face of a rotary board 29, equal to the height of mixed flow blades 33a-33f whereas a centrifugal blade 31a has height L1 shorter by a predetermined amount than L2. Consequently, the gap between the end of the centrifugal blade 31a and the inner wall of end frame is larger than the gap between the ends of other blades 31b-33f and the inner wall of the end frame. As a result, interferential noise between a cooling fan 15 and the inner wall of the end frame is distributed over a wide frequency range with nineth components corresponding to the number of blades being suppressed, resulting in total reduction of sensitive noise.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an internal fan type vehicle alternator equipped with a cooling fan inside a frame body.

[Prior Art] This type of vehicle alternator has conventionally been constructed by inserting a rotor with a cooling fan fixed to its end face into a stator formed on the inner wall of a frame body. By blowing cooling air from a cooling fan generated by rotation directly onto the stator windings, heat generation in the stator windings during power generation is suppressed.

[Problem to be solved by the invention] However, in recent years, there has been a demand for smaller and lighter AC generators for vehicles, and with such internal fan type generators (with the smaller size, cooling fans and inner walls of the frame are required). Because of this, the interference noise generated between the blades of the cooling fan and the inner wall of the frame increases, which is one of the causes of vehicle noise.

Therefore, the present invention was made with the object of suppressing vehicle noise by suppressing the interference noise generated between the blades of the air cooling fan and the inner wall of the frame.

[Means for Solving the Problems] The present invention has been made to achieve the above object] A stator in which stator windings are wound along slots provided in a hollow stator core; A rotor that can be inserted into the rotor and has a large number of pole cores protruding around its periphery; a cooling fan that has a large number of blades around a guard 2 disposed on an end face of the rotor; the stator, the rotor, and a frame body surrounding the cooling fan and having a cooling air discharge window formed around the stator winding, wherein at least one blade of the cooling fan, The gist of this invention is an alternator for a vehicle that is characterized by being formed in a size different from other blades.

[Operations] In the vehicle alternator of the present invention configured in this manner, a cooling fan is disposed on the end face of the stator, and as it rotates together with the rotor, it blows cooling air onto the stator windings to generate electricity. This suppresses the heat generated in the stator windings.

At this time, interference noise is generated between the blades of the cooling fan and the frame surrounding them, but since at least one blade of the cooling fan is formed in a different size from the other blades, the interference noise is generated. Among these, the noise component generated decreases in proportion to the number of blades, and the entire interference sound is dispersed over a wide frequency range.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

First, FIG. 2 is a sectional view showing the overall structure of the vehicle alternator according to the embodiment.

As shown in the figure, a pair of end frames 1.2 as frames forming the outer shell of the generator are both formed in a bowl shape, and are fixed to each other by bolts 3 with their openings directly joined. A stator core 5 is fixed to the inner periphery of the end frames 1 and 2, and stator windings 5a are wound along a number of slots (not shown) formed in the stator core 5. Also, inside the end frame 1.2 (Table Bearing 9)
．． A pair of claw-shaped ball cores 13 and 14, each having a rotor winding 2 wound thereon, are positioned inside the stator core 5. It is set up to do so.

Furthermore, cooling fans 15 and 16 are fixed to the side surfaces of each pole core 13 and 14, respectively, and a pulley 18 (not shown) for transmitting engine rotation to the shaft 11 is mounted on the end frame 1 side of the shaft 11. It is attached via a nut 19.

On the other hand, a pair of positive and negative heat sinks 2 have a rectifying element (leftifier) attached to the outside of the end frame 2.
0,21, rotor winding 1 in contact with slip ring 22
2, a brush holder 24 that holds the brush 23, and a connector 2 for an IC regulator (not shown) that is included in the generator and adjusts the output voltage.
6. Various electrical functional parts such as an 8-power terminal 27 connected to the + side heat sink 20 and used to take the output voltage rectified by the rectifying element are provided. It is fixed to frame 2.

In this way, the vehicular alternator of this embodiment (which is configured almost the same as a conventional vehicular alternator)
Next, the configuration of the cooling fan 15, which is the main part related to the present invention, will be explained using FIGS. 1 and 3.

FIG. 1 is a front view showing the configuration of the cooling fan 15. As shown in FIG. As shown in the figure, cooling air is sent in the radial direction of the rotor plate 29 to cool the stator winding 5a around the rotor plate 29, which is welded and fixed to the side surface of the pole core 13 at six welds 29a. The three centrifugal blades 31a to 31c that rotate
Large diagonal flow blades 33a to 33f are installed perpendicularly to the rotor plate 29 and blow cooling air in the axial direction of the shaft 11 to cool the rotor winding]2. It is erected diagonally. Further, ribs 35a to 35a extend from the surface of the rotating plate 29 to the surface of each blade 31a to 33f.
35i are formed respectively, and each blade 31a to 33
f is held at a predetermined angle with respect to the rotating plate 29.

Here, the centrifugal blade 31a whose upper end surface is shown painted black is formed shorter than the other centrifugal blades 31b and 31C. That is, the centrifugal blades 31b, 31cf&
As shown in FIG. 3(B), the height of the rotating plate 29 from the bottom surface is L2, which is equal to the height of the mixed flow blades 33a to 33f, while the centrifugal blade 31
The height of a (as shown in FIG. 3(A) 1; Ll is lower than L2 by a predetermined amount).

Returning to Fig. 2, the cooling fan configured in this way] 5 (
It is driven to rotate integrally with the ball core 13 by the rotation of the pulley 8, and blows cooling air onto the rotor winding 12 and stator winding 5a to suppress heat generated by power generation. In addition, the cooling air that has passed through the rotor winding 12 or the stator winding 5a is discharged from a discharge window 37 formed in the side surface of the end frame 1.

In addition, the height of each centrifugal blade of the cooling fan 16 is 2.
Right configured similarly to cooling fan 15 except that
The rotor winding] 2 and the stator winding 5a are cooled.

In the automotive alternator of the embodiment configured in this way (even if the distance between the tips of each of the blades 31a to 33f of the front cooling fan 15 and the inner wall of the end frame 1 is configured to be very narrow, the height of the centrifugal blade 31a is Saga, other blade 31
Since the height Ll is lower than the height of the centrifugal blades 31a to 33f, the distance between the tip of this centrifugal blade 31a and the inner wall of the end frame 1 is smaller than the distance between the tips of the other blades 31b to 33f and the inner wall of the end frame 1. I hear it.

For this reason, the interference sound (mountain) generated between the blades 31a to 33f of the cooling fan 15 and the inner wall of the end frame 1. noise is suppressed.

Here, when the height Ll of the centrifugal blade 31a is extremely small, the 9th order component of the surface interference sound almost disappears, but the 8th order component of the interference sound increases instead, and the noise suppression effect is insufficient. There are times when I am not able to perform to my full potential. Furthermore, if the height Ll of the centrifugal blade 31a is made too small, the cooling effect of the cooling fan 15 will also be reduced.

Therefore, it is desirable to set the height Ll of the centrifugal blade 31a to a value that does not affect the eighth-order component of friend interference sound or the cooling effect of the cooling fan 75. The ratio of the height Ll of the blade 31a to the height L2 of the other centrifugal blades 31b to 33f is (0,
8: 1. By setting the height Ll of the centrifugal blade 31a so that the height Ll of the centrifugal blade 31a becomes O), the increase in the 8th order component of the interference sound is kept within a negligible range, and the cooling effect of the cooling fan 15 is prevented from decreasing. . In addition, in order to maintain the cooling effect, it is desirable that ILLI/L2 is 0.5 or more.

Next, the noise suppression effect of the automotive alternator of this example will be explained based on FIG. 4.

FIG. 4 shows an automotive alternator according to the embodiment and a conventionally well-known automotive alternator constructed in the same manner as the embodiment except that the height of all cooling fan blades is set to L2. , is a comparison of the noise levels of the ninth-order components generated at various rotation speeds. Note that in the figure, A represents the noise level of the automotive alternator of the embodiment, and 8 represents the noise level of a conventional automotive alternator with blades of equal height.

As shown in the figure, the 9th order component of the interference sound increases as the rotation speed increases in both generators, but at any rotation speed, this example is better than the conventional generator. It can be seen that the noise level is lower than in the example.

In this way, the automotive alternator of this embodiment can reduce the 9th order component of the single-air interference sound and disperse the entire interference sound over a wide frequency range, thereby reducing the perceived vehicle noise as a whole. Can be suppressed.

In this embodiment, only the blade 31a of the cooling fan 15 on the end frame 1 side is replaced with the other blades 31b to 33.
Although it is formed smaller than f, multiple blades may be formed smaller than other blades, and the cooling fans on both sides of the pole core may also be formed like this.Further 1: Inner wall of end frame If there is sufficient space between the cooling fan and the tip of the blade of the cooling fan, at least one blade in the first table may be formed larger than the other blades, and the same effect as in this embodiment can be obtained.

[Effects of the Invention] As detailed above, in the vehicle alternator of the present invention (out of the interference noise generated between the blades of the upper cooling fan and the frame body, the noise generated in accordance with the number of blades) Since the components can be reduced and the entire interference sound can be dispersed over a wide frequency range, the perceived vehicle noise as a whole can be suppressed.

[Brief explanation of drawings]

Figure 1 is a front view showing the configuration of the cooling fan of the embodiment;
The figure is a cross-sectional view showing the overall configuration of a vehicle alternator to which the cooling fan is applied, FIG. 3 is an explanatory diagram showing each blade of the cooling fan, and FIG. 4 is the noise of the vehicle alternator according to the embodiment. This is a graph explaining the suppressing effect. 1.2... End frame 5a... Stator winding 12... Rotor winding 13.14-... Pole core 15.16... Cooling fans 31a-31c... Centrifugal blades 33a-33f・・・Diagonal flow blade

Claims (1)

[Claims] A stator in which stator windings are wound along slots provided in a stator core, and a stator that is rotatably inserted into the stator and has a number of pole cores protruding around its periphery. a rotor; a cooling fan disposed on an end face of the rotor and having a large number of blades formed around the rotor; A frame body having a discharge window formed therein, and an alternator for a vehicle, characterized in that at least one blade of the cooling fan is formed in a size different from that of the other blades. AC generator for vehicles.