JPS6237414Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention mainly relates to an improvement in the structure of a generator used in a vehicle to reduce the noise generated when a cooling fan rotates at high speed. This type of generator rotates in proportion to the rotation of the engine, so if it is operated at high speed, the noise from the cooling fan will increase.

First, a conventional device of this kind will be explained with reference to FIG.

FIG. 1 is a diagram showing a conventional generator of this type. In the figure, 1 is a cooling fan driven by an engine (not shown), 2 is a front bracket provided adjacent to the cooling fan, 3 is a rear bracket, 4 is a stator provided integrally with each of the brackets, and 5 is a stator provided integrally with each of the brackets. 6 is a rectifier, 21 is an air circulation hole in the front bracket 2, and 31 is an air circulation hole in the rear bracket 3. In the configuration shown in the figure, cooling air flows from the outside of the rear bracket 3 as the cooling fan 1 rotates, flows in the direction of arrow a, and cools the rectifier 6, stator 4, and rotor 5. Figure 2 qualitatively shows the output current characteristics, air volume, and stator temperature rise with respect to rotational speed of a conventional general generator for two sizes of distribution holes 21 and 31 (large hole → small hole →). Figure 3 shows the relationship between the air volume and noise with respect to the rotational speed of a conventional general generator, as well as the size of the circulation holes 21 and 31 (large holes→small holes→
) This shows two ways.

That is, in the case of a generator with a conventional structure, the air volume of the cooling fan 1 increases as the rotation of the generator increases, resulting in increased noise. In this case, the air flow holes 21 and 31 of each bracket 2 and 3 were made smaller to reduce the air volume of the cooling fan 1 to reduce noise during high speed rotation. Since the air volume of the cooling fan 1 decreases in the low rotation range of the generator, the temperature rise of the generator in the low rotation range becomes extremely high, causing a problem that impairs the characteristics of the generator.

This idea was created in view of the above-mentioned problem, and since the temperature rise of the generator decreases when the generator exceeds a certain rotation speed, in the rotation range where the temperature rise decreases, the circulation hole of the bracket is The purpose of the present invention is to provide a charging generator for a vehicle that can obtain sufficient power generation characteristics during low speed rotation and reduce noise during high speed rotation by providing a shielding plate that acts to reduce the amount of air generated. There is.

An embodiment of this invention shown in FIGS. 4 to 6 will be described below.

That is, in FIGS. 4 to 6, 7 is a flexible shield plate fixed to the front bracket 2, 71 is a fixed part fixed to the front bracket 2, and 72 is the free end of the shield plate 7. and is interposed within the communication hole 21. 73 is a connecting portion that connects this free end with the fixed portion 71, and 74 is a bent portion where the shielding plate 7 is bent so as to have a constant spring constant.Usually, as shown in FIG. The connecting portion 73 is set at an angle θ with respect to the fixed portion 71.

In this example, the rotation speed of the generator is 7th.
Until the Nrpm shown in the figure is reached, the free end 7 of the shielding plate 7 is
2 receives the pressure of the air flowing through the circulation hole 21, but since the pressure of the air is smaller than the spring force of the bent portion 74 of the shielding plate 7, the shielding plate 7 Since this state is maintained, the amount of air generated by the cooling fan 1 is sufficiently large, effectively suppressing the temperature rise of the generator. Next, when the rotation of the generator increases and exceeds Nrpm shown in FIG. 73, free end 7
2 is instantly pushed upward as shown in FIG. 6, and the opening area of the communication hole 21 is reduced. As a result, the air volume of the cooling fan 1 is instantaneously reduced, lowering the noise level. As mentioned above, the characteristics of the temperature rise, noise level, and air volume of the generator as the rotation of the generator increases are as shown in Figure 7.As is clear from Figure 7, in this example, the shielding plate 7, in the rotation range where the temperature of the generator increases significantly, the air volume of the cooling fan 1 is increased to effectively cool the generator.
Further, in a rotation range where the temperature rise of the generator is small and the noise level of the cooling fan 1 is high, the air volume is reduced by the shielding plate 7, and the problem of noise generation by the cooling fan 1 can be prevented.

In the above description, the shielding plate 7 is provided on the front bracket 2, but it is also possible to provide the shielding plate 7 on the rear bracket 3 so that the amount of air flowing through the circulation hole 31 of the rear bracket 3 is reduced by the shielding plate 7. You can also do this.

As described above, in this invention, noise during high-speed rotation of the generator can be easily suppressed by providing the bracket with a shielding plate that can reduce the amount of air flowing through the cooling fan in response to the wind speed flowing through the circulation holes. It has excellent effects.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional open-type vehicle charging generator, Figure 2 is a typical conventional characteristic curve diagram showing the relationship between output current, cooling air volume, and temperature rise, and Figure 3 is a conventional typical characteristic curve diagram showing the relationship between output current, cooling air volume, and temperature rise. Fig. 4 is a cross-sectional view showing an embodiment of this invention, and Fig. 5 is a characteristic curve diagram showing the relationship between cooling air volume and noise. FIG. 6 is a partial sectional view showing the change in the position of the shielding plate when the rotation speed exceeds a certain number of revolutions in the embodiment shown in FIG. 4 of this invention. FIG. 7 is a noise characteristic diagram showing the effect brought about by the shielding plate of the embodiment shown in FIG. 4 of this invention. In the figure, 1 is a cooling fan, 2 and 3 are brackets, 21 and 31 are circulation holes, 7 is a shielding plate, 71 is its fixed part, 72 is its free end, 73 is a connecting part,
74 is a bent portion. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Scope of utility model registration request] a cooling fan attached to the rotating shaft of the charging generator and driven by the engine; a first bracket having a circulation hole for air drawn into the charging generator by the cooling fan; a second bracket having a circulation hole for discharging to the outside; one end fixed to at least one of the first or second bracket; the other free end placed in the air circulation part of the circulation hole; and a free end connected by a bent portion having a predetermined spring constant, and when the wind speed flowing through the flow hole is equal to or higher than the predetermined wind speed, the spring force of the shield plate is The charging generator for a vehicle is configured to operate the free end against the flow of air to reduce the amount of air flowing through the flow hole.