JPS5914338A - Vent cooler for rotary electric machine - Google Patents

Abstract

PURPOSE:To enhance the intrinsic vibration frequency of a centrifugal fan by securing the outside disk of the fan to a rotational shaft via a blade and spokes. CONSTITUTION:A blade 7 is secured with rivets 11 between an inside annular disk 6 engaged with a rotational shaft 1 and an opposed outside annular disk 5, and strip spokes 8 which extend radially from the inner peripheral side of the disc 5 toward an axial center are provided circumferentially at an equal interval. Thus, the disk 5 is heretofore secured and supported only by the blade 7. Since the disk 5 is however secrued and supported by the blade 7 and the spokes 8 to the shaft 1, the circumferential intrinsic vibration frequency of the blade 7 and the disk 5 can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a ventilation cooling device for a single rotary cylinder, and particularly to an improvement of a centrifugal fan fixed to a rotor.

[Technical background of the invention and its problems]

Generally, a centrifugal fan is made of a thin steel plate with a thickness of about 3 to 9 mm. This centrifugal fan is widely used in self-backflow type rotating electric machines. As is well known, an AC motor has a vibration frequency that is twice the frequency of the C power supply at the time of starting. In particular, the salient pole type four-stage turtle V1 machine generates a stronger pulsating torque than its salient pole type. For example, if the power source is 601 (2), there will be a pulsating torque of 0 to 120 Hz at startup. Therefore, it is desirable to set the natural frequency of the members that make up the rotor to avoid resonance with the above-mentioned torsional vibration. As mentioned above, centrifugal fans are made of steel plates, so their natural frequency is low and resonance can cause fatigue failure of the fan.

As a countermeasure, the blades and the annular outer disk that supports the outside of the blades are made thicker to increase their rigidity, but this not only increases the weight but also makes it difficult to bend the blades. :When welding the base of the blade, which has the disadvantage of easily generating hair cracks due to bending, there is an undercut in the welded part, and the repeated fatigue strength of the welded part is reduced by 42% compared to the base material. do.

Furthermore, when the blade is fixed with rivets, its natural frequency is set in advance, but it is extremely difficult to obtain a predetermined natural frequency due to variations in the tightness of the rivets.

[Purpose of the invention]

The present invention has been made in consideration of the above-mentioned circumstances, and an object of the present invention is to provide a ventilation cooling device for a rotating electrical machine equipped with a centrifugal fan made of thin steel plate and having a high natural frequency of L7.

[Summary of the invention]

The ventilation cooling device for a rotating electric machine of the present invention achieves the above object by fixing the outer disk of a centrifugal fan having opposing disks attached to the rotor to the rotor via a plurality of supporting members. It is.

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to the drawings. In FIGS. 2 and 3, a centrifugal fan 4 is fixed to a rotating shaft 1 of a rotor. This centrifugal fan 4 includes an annular inner disk 6 fitted onto a rotating shaft 1 and an annular outer disk 5 facing opposite to each other.
The blade 7 is fixed with a rivet 11 between. Four band-shaped spokes 8 are provided at equal intervals in the circumferential direction, extending radially from the inner peripheral side of the outer disk 5 toward the axis.

The cross-sectional shape of the spokes 8 is set to strengthen the acting force in the circumferential direction (2).In other words, in this embodiment, the cross section is rectangular, and the longitudinal direction of the lever is oriented in the circumferential direction. .

One end side is fixed to the rotating shaft 1 by tightening bolts 9 (two screws) on the surface of the rotating shaft 1 through adjustment plates 12, respectively.

In addition, 2 is a salient magnetic pole on the rotating shaft, a 3-barged stator, and 10 is a stationary side I: an attached air guide cover that covers the outside of the fan.

Explain the action. In the conventional structure, the outer disk 5 was fixedly supported only by the blades 7, but since it is fixedly supported on the rotating shaft 1 by the blades 7 and spokes 8, the circumferential direction of the blades 7 and the outer disk 5 system is The natural frequency can be increased. [7 Therefore, for example, to exceed the maximum forced torsional vibration frequency of 120H2 that occurs when starting an AC motor, that is, to avoid resonance, this can be easily achieved even with a thin steel plate by adopting the above structure. Can be done.

Furthermore, since the centrifugal fan can be constructed from the thin steel plate f2, it is possible not only to reduce the weight of the rotor but also to obtain a low inertia electric motor.

In particular, in the case of the parallelogram-shaped blade shown in Figure 1m, the sides of the blade are long. Therefore, it is effective in compensating for the disadvantage in mechanical strength in supporting the inertia of the outer disk 5.

In another embodiment shown in FIG. 3, the spokes 8 are prepared separately and fixed to the outer disk 5 by rivets. Such a structure not only achieves the same effect as the above-mentioned embodiment, but also can be installed in an existing rotating electric machine.
This has the effect of improving old fans with simple work.

In the case of this embodiment, if the spokes 8 are manufactured from pipes, the rigidity of the centrifugal fan not only in the circumferential direction but also in the axial direction can be dramatically increased.

Furthermore, another embodiment shown in FIG. 4 is a ventilation cooling device for a rotor in the form of a rotary tube, in which a centrifugal fan is mounted on a holding plate 14 that clamps a cylindrical iron core 13 fixed to a rotating shaft 1. 4 are installed.

Spokes 8 of a band plate are fixed at the first several positions between the outer disk 5 and the inner disk 6 in the circumferential direction. In a case where the centrifugal fan 4 has a relatively large outer diameter as in this embodiment, the spokes 8 are fixed to the inner disk 6I. By substantially fixing the scale to the rotor, the scale can be easily assembled, rather than having the same functions and effects as the previous embodiment.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to easily obtain a centrifugal fan with a high frequency f1 made of a thin steel plate, and there is an effect of providing a ventilation cooling device for a rotating electric machine with high mechanical quality. .

[Brief explanation of drawings]

1 "Figure 1 is a longitudinal cross-sectional view showing an embodiment of the ventilation cooling device for 15 rotating machines according to the present invention, and Figure 2 is a side view of Figure 1, and Figure 3 is a side view of Figure 1.
The figure is a sectional view of a main part showing another embodiment, and FIG. 4 is a longitudinal sectional view of a ventilation cooling device showing still another embodiment. 1... Rotation axis 2... Salient magnetic pole... Centrifugal fan 5... Outer disk (second disk) 6... Inner disk (first disk) 7. ...Blade 8...Spoke 9...Bolt 11...Rivet 14...
Holding board (7317) Agent Patent attorney Noriyuki Chika (and 1 other person) No. 1g 219- No. 211

Claims (1)

[Claims] A centrifugal fan configured by fixing two blades C between the opposing disc 10 and the second disc, the first disc of this centrifugal fan is fixed to the rotor C2 and cooled by rotation C2. In order to supply wind (2L5), install the ventilation cooling device C2 for the rotating electric machine,
A ventilation cooling device for a rotating electric machine, characterized in that a second disc of a centrifugal fan is fixed to a rotor via a rotor support member.