JPS5854858Y2 - Cooling structure of rotating electrical machines - Google Patents

Description

[Detailed description of the invention] The present invention relates to a cooling structure for a rotating electric machine, and is intended to improve the cooling effect by increasing the air blowing effect by a radial fan attached to the end of the rotating shaft in a completely enclosed fan-shaped machine. .

Rotating electrical machinery can be classified from a mechanical perspective: (1) classification by frame shape (open type or fully enclosed type), (2) classification by protection method (unprotected type, dust-proof type, explosion-proof type, etc.); 3) The type is determined by the combination of the above three elements, classified by ventilation method (self-ventilation, external ventilation).

A fully enclosed external fan-shaped rotating electric machine has a completely closed frame, and has a structure in which the frame 3 is cooled by a fan 2 attached to the end of a rotating shaft 1, as shown in the conventional example shown in FIG.

The frames of conventional totally enclosed external fan-shaped rotating electrical machines include those using cast metal frames and those using steel plate frames.

Steel plate frames are easy to manufacture, but the temperature rise in the windings is not acceptable to customers as a replacement for cast frames because the frame temperature increases even if a product that satisfies the standard values is created. is the current situation.

The main reason for this is that the ventilation path 4 of the fully enclosed steel plate frame motor is not provided with any ventilation rectifying plate at all, but instead runs along the axis.
The air passage 4 is not provided with a rectifier plate such as a rib, and even if it is provided, it is integrated with the frame 5 side and is provided only in a short range of the frame surface.

Therefore, most of the cooling air has a tangential component with respect to the frame, and a small axial component at the outlet of the air passage 4, and most of the wind coming out of the blades has a wind velocity component, which makes it difficult to shift to an axial component.

Therefore, there was a drawback that a sufficient cooling effect could not be obtained.

In this case, the angle of the wind coming out of the fan cover 6 was 40' or more with respect to the axis.

By the way, if the wind speed near the entrance of the ventilation passage 4 is 100%, it decreases to about 20% at the exit.

The curve diagram in FIG. 12 shows the degree of decrease in wind speed.

On the other hand, in order to improve the cooling effect, the diameter of the fan was increased and the ventilation passages were narrowed, which resulted in increased noise, and this method also had its flaws.

As described above, the maximum output of rotating electric machines with fully enclosed steel plate frames is not economically advantageous compared to conventional cast ribbed frame products, which has become a problem.

In view of these deficiencies, the present invention aims to improve the cooling effect of the frame, make it smaller and lighter, reduce the amount of iron core and winding used, and reduce the basic dimensions of the parts so that it can be used even in open types. The aim is to standardize the system and also to achieve lower noise levels.

In short, the idea of this invention is that the wind coming out of a radial fan necessarily has a tangential component in addition to the axial component, so the wind cools only the area near the fan cover of the cylindrical frame without ribs and moves away from the frame. Taking note of the drawbacks, the present invention aims to improve the manufacturing method and installation of a rectifier plate that rectifies the flow in the axial direction at the outlet of the fan cover.

The rectifying plate is formed by providing an L-shaped or U-shaped notch in a band-shaped plate and bending it at an almost right angle. This is done by fixing it to the inside of the fan cover.

The configuration will be explained in detail below based on FIGS. 2 to 11.

FIG. 2 is a cutaway sectional view of the main parts of the rotating electric machine. A frame 5 provided on the winding side is cooled by a fan 2 attached to the rotating shaft, and the fan 2 is provided with a fan cover 6. .

A gap 4 extending in the axial direction between one side end of the fan cover 6 or a cylindrical jacket welded thereto and the frame 5
(ventilation ducts) are provided.

As shown in FIGS. 4 to 11, which are attached to the inner circumferential surface of the frame 3, the unfolded plane is composed of a band-shaped iron plate 7, and the collar has a length 8 corresponding to the gap size of the ventilation passage 4. A rectifying plate 8 is provided by punching out and bending an iron plate 8' portion so that the portion thereof stands up.

This current plate 8 is made to have a required dimension in the axial direction.

Thus, the strip iron plate 7 is formed into a cylindrical shape, and the rectifier plate 8 is provided in the ventilation passage 4 close to the fan.

FIGS. 4, 5, 8, and 9 show different embodiments of the shape and manufacturing method of the current plate, respectively.

The cooling air emitted from the fan 2 can be functionally expressed as a three-dimensional vector, as is well known.

In this case, what can be effectively used as the cooling air is the air near the surface of the frame 5, that is, the axial component.

However, when the air comes out from the fan 2, most of the air is composed of radial components and fan circumferential speed components, and the fan circumferential speed component is larger.

By the way, the function of the fan cover 6 is so formed that it can convert a radial component into an axial component.

This alone cannot greatly change the circumferential speed component into the axial component, and there is significant wind diffusion in the tangential direction.

The function of the baffle plate 8 is to reduce the wind escaping in the tangential direction, so that the circumferential velocity component can be changed more in the axial direction, that is, in the axial direction of the frame 5.

Therefore, the cooling air is effectively increased in the axial direction. Incidentally, the 13th
The figure shows the results of measuring the wind speed at the fan outlet and the decrease in wind speed at the end of the frame 5, that is, the ventilation passage 4, in the case a without the current plate 8 and in the case with the current plate 8.

According to the curve diagram, when the baffle plate 8 was provided, the wind speed in the axial direction was approximately doubled at the end of the frame on the side opposite to the fan.

As a result, we were able to significantly reduce the temperature rise in the frame.

The size of the gap between the ventilation channels and the length of the current plate in the axial direction are determined by the capacity of the rotating electrical machine, the rotational speed, the size of the fan, the air volume, etc. Since it is attached to the inner surface of the fan cover to guide the circumferential component of the wind in the axial direction, the degree of freedom in design increases, and it can be used in all fields where air flows in the axial direction. It can be applied to

In particular, the cooling effect on rotating electric machines such as induction machines, DC machines, and synchronous machines is remarkable.

[Brief explanation of drawings]

Fig. 1 is a schematic structural diagram for explaining a conventional fully enclosed external fan-shaped rotating electrical machine, Fig. 2 is a longitudinal cross-sectional view of essential parts of an embodiment of a completely enclosed external sector-shaped rotating electrical machine based on the present invention, and Fig. 3 is a rectifier. 4.5 and 8.9 are developed plan views of the rectifying plates of different embodiments, 6 and 10 are longitudinal sectional front views, and 7 and 11 are longitudinal sectional views showing the mounting structure of the plate. Side view, Figure 12 and Figure 1
FIG. 3 is a wind speed reduction curve diagram for explanation. 1 is the rotating shaft, 2 is the fan, 4 is the ventilation path, 5 is the frame,
6 is a fan cover, and 8 is a rectifier plate.

Claims (1)

[Scope of utility model registration request] In an external fan-shaped rotating electrical machine having a radial fan that rotates outside the machine, a fan cover that covers one end of the frame and the second radial fan, and the frame having a substantially cylindrical shape without fins, A plurality of ventilation passages formed between the inside of the ventilation outlet side end of the fan cover covering one end and the outside of the frame extend in the axial direction and are spaced apart in the circumferential direction. A rectifying plate is provided, and this rectifying plate is formed by providing an L-shaped or U-shaped notch in a band-shaped plate and bending it at an approximately right angle,
A cooling structure for a rotating electrical machine, characterized in that the band-shaped plate having an arc shape with the bent portion facing inside is fixed to an inner surface of the fan cover.