JPH0315242A - External fan type rotary electric machine equipped with air cooler - Google Patents

Abstract

PURPOSE:To increase ventilating amount without increasing noise due to an external fan and improve cooling efficiency by a method wherein the ventilating vanes of the centrifugal type external fan are provided on both surfaces of a main plate while cooling air is induced from both side surfaces of the axial direction of a box type external fan cover surrounding the external fan. CONSTITUTION:An air cooler 2, circulating internal air by the effect of an internal fan, is attached to the outer periphery of an electric machine main body 1 while a circulation type external fan 14, surrounded by a box type external fan cover 15, is secured to the end of a rotary shaft 13, projected from the end face of the electric machine main body 1. An air duct 15a for sending cooling air into the casing of the air cooler 2 as shown by arrow signs in a diagram by the effect of an external fan 14 to cool internal air by circulating the cooling air, is provided on the outer periphery of the external fan cover 15. The external fan 14 is formed of ventilating vanes 14a provided radially on both surfaces of a main plate 14b while cooling air is induced from the central part of both axial side surfaces of the external fan cover 15. According to this method, the amount of cooling air may be increased without enlarging the outer diametral size of the external fan whereby noise due to the external fan may be reduced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention improves an external fan-shaped rotating electric machine with an air cooler so that it can be efficiently cooled by increasing the amount of cooling air without increasing the noise caused by the external fan. related to what was done.

[Prior Art] A conventional example of an external fan-shaped rotating electrical machine with an air cooler will be described with reference to FIG. In this figure, a box-shaped air cooler 2 is attached to the upper outer periphery of an electric machine body 1, and a centrifugal outer fan 4 is fixed to the end of a rotating shaft 3 protruding from the end face of the electric machine body 1. The cooler 2 communicates with the inner chamber of the electric machine main body 1, and internal air is circulated within the box due to the rotation of an inner fan (not shown). This cooler 2 is designed to cool the inside air by exchanging heat with the inside air by causing cooling air to flow through an axial heat absorption pipe (not shown) as shown by the dotted arrow by the action of an outside fan 4. The outer fan 4 is
It is surrounded by a box-shaped outer fan cover 5, and the cooling air is sucked in from the center of the outer surface of the outer fan cover 5. A hook-shaped air duct 5a is provided at the upper part of the outer periphery of the outer fan cover 5 for feeding cooling air into the heat absorption tube.

[Problem to be solved by the invention]

The above structure has a drawback in that when the outer diameter of the outer fan 4 increases in order to obtain the required cooling scenery, the noise accompanying the rotation of the outer fan 4 increases.

In order to eliminate the above-mentioned drawbacks, this invention is capable of efficiently cooling by increasing the amount of cooling air without increasing the noise caused by the external fan, and furthermore, the rotating shaft can be rotated in either counterclockwise or clockwise direction. To provide an external fan-shaped rotating electric machine with an air cooler that can perform good cooling even when the air is heated.

[Means to solve the problem]

In order to achieve the above-mentioned object, this group of inventions provides the blowing blades 14a of the centrifugal outer fan 14 on both sides of the main plate 14b, and the shaft of the box-shaped outer fan cover 15 that surrounds the outer fan l4. Cooling air is sucked in from both sides.

Further, invention 2 is the invention 1, in which the exit angle of one of the double-sided air blowing blades is a backward facing blade with respect to counterclockwise rotation, and the exit angle of the other blade is set as a backward facing blade with respect to clockwise rotation.

[Function] In invention 1, since the blower blades 14a of the outer fan 14 are provided on both sides of the main plate 14b, the amount of cooling air can be increased without increasing the outer diameter of the outer fan 14. Noise caused by the outside fan 14 can be reduced.

In invention 2, in addition to the effect of invention 1, since either one of the blower blades 24a, 24c is a backward-facing blade in either direction of rotation A or C, fan efficiency is improved;
Even if the efficiency of the other one decreases, the overall efficiency improves and noise also decreases.

〔Example〕

FIG. 1 shows an example construction, and parts indicated by the same reference numerals as in FIG. 3 are the same parts. In this figure, the electric machine body 1
A box-shaped air cooler 2 is attached to the outer periphery of the machine to circulate the inside air by the action of an internal fan (not shown), and a box-shaped external fan cover 15 surrounds the end of a rotating shaft 13 protruding from the end surface of the electric machine body 1. A centrifugal outer fan 14 is fixed. A hook-shaped air duct 15a is provided on the outer periphery of the outer fan cover 15 for sending cooling air produced by the outer fan l4 into the box body of the cooler 2 as shown by the arrow and flowing through it to cool the inside air. The outer fan l4 has air blowing blades l14a radially provided on both sides of the main plate 14b, and is configured to suck cooling air from the center of both axial side surfaces of the outer fan cover l5.

When the outer diameter of the outer fan 14 is changed, the resulting change L2 in the noise level can generally be expressed as L+>=70log (outer diameter ratio). On the other hand, the cooling air volume Q due to the action of the outside 814 changes with Q factor (outer diameter dimension ratio) 3.

Therefore, if an attempt is made to increase the outer dimensions of the outer fan 14 to obtain the required amount of cooling air, the noise accompanying the rotation of the outer fan 14 will increase. Therefore, the cooling air volume can be increased without increasing the outer diameter of the outer fan 14.
This makes it possible to reduce the noise caused by the external fan l4.

FIG. 2 is a sectional view perpendicular to the axis of the outer fan of the second embodiment, which is used in place of the outer fan 14 of FIG. Blower blades 24a, 24 provided on both sides of the main plate 24b of the outer fan 24
In c, the blade exit angle βa of one of the blower blades 24a is a known backward-facing blade with respect to the counterclockwise rotation A,
The exit angle Be of the other blower blade 24c is rotated clockwise C
It has backward facing feathers.

It is well known that backward facing vanes are more efficient and produce less noise than the radial vanes of Example I. In either rotation direction A or C, one of the blowing blades becomes a forward-facing blade, which is disadvantageous in terms of efficiency and noise. Suitable for things that are not fixed or that use reversible rotation.

[Effects of the Invention] According to this group of inventions, in an external fan-shaped rotating electric machine with an air cooler, the blowing blades of the centrifugal external fan are provided on both sides of the main plate, and the fan blades are provided on both sides in the axial direction of a box-shaped external fan cover that surrounds the external fan. Since the cooling air is sucked in from the surface, the effect of increasing the amount of cooling air and efficiently cooling can be obtained without increasing the noise caused by the external fan.

Further, a configuration in which both of the blowing blades are rearward-facing blades in both rotational directions is effective in improving cooling and noise when used for an item whose rotational direction is not determined or an item that rotates reversibly.

[Brief explanation of drawings]

FIG. 1 is a partial longitudinal sectional view of the first embodiment, FIG. 2 is a sectional view perpendicular to the axis of the outer fan of the second embodiment, and FIG. 3 is a partial vertical sectional view of the conventional example.

Claims (1)

[Claims] 1) A box-shaped air cooler is attached to the outer periphery of the electric machine body to circulate the inside air by the action of an inner fan, and a box-shaped outer fan is attached to the end of the rotating shaft protruding from the end surface of the electric machine body. In a rotating electric machine in which a centrifugal external fan surrounded by a cover is fixed and the cooling air generated by the external fan flows through the box of the air cooler to cool the internal air, the blowing blades of the external fan are attached to the main plate. 1. An external fan-shaped rotating electric machine with an air cooler, characterized in that the cooling air is provided on both sides and the cooling air is taken in from both sides in the axial direction of the external fan cover. 2) In the external fan-shaped rotating electric machine with an air cooler according to claim 1, the exit angle of one of the double-sided air blowing blades is a backward-facing blade with respect to counterclockwise rotation, and the exit angle of the other blade is a backward-facing blade with respect to clockwise rotation. An external fan-shaped rotating electrical machine with an air cooler, which is characterized by: