JPH1032961A - Rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary electric machine where a cooling efficiency through a cooling fan can be positively increased and the electric machine can be miniaturized and made light satisfactorily. SOLUTION: In an electric motor in a system for cooling by ventilating the outer surface of a housing 1 by a cooling fan 9, a shroud 9A is provided between impeller blades 9B of the cooling fan 9 and the space between the impeller blades 9B is divided in nearly diameter direction, thus creating a plurality of divided air streams as shown by arrows A and B and guiding the air streams to the outer surface of the housing 1 independently by a fan guide 11 and hence increasing a blast efficiency due to the cooling fan 9, at the same time increasing cooling effect since the outer surface of the housing 1 can be cooled while being surrounded by a plurality of air streams, and hence miniaturizing and making light the rotary electric machine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating electric machine of a self-ventilated cooling type provided with a cooling fan, and more particularly to a rotating electric machine suitable for a relatively small-capacity general-purpose induction motor.

[0002]

2. Description of the Related Art As a relatively small-capacity general-purpose induction motor, a squirrel-cage induction motor has been widely used.
Therefore, a conventional example of such an induction motor is shown in FIG.
In the drawing, reference numeral 1 denotes a housing, which is formed in a substantially cylindrical shape by casting an iron-based material such as cast iron or a light metal material such as aluminum, and constitutes a casing of the electric motor. 1a is a radiation fin which is radially arranged on the outer periphery of the housing 1 as a plurality of strips arranged along the axial direction,
It is formed integrally with the housing 1. Reference numerals 2A and 2B denote end brackets, which are attached to the openings on both sides of the housing 1 by fitting them in with spigots.

[0003] Reference numeral 3 denotes a stator, which is wound around a stator core 3A formed by laminating a plurality of electromagnetic steel plates such as silicon steel plates, and a plurality of slots formed on the inner periphery of the stator core 3A. And is inserted into the housing 1 and is fitted and fixed to the inner peripheral portion thereof.

[0004] Reference numeral 5 denotes a rotor having a rotating shaft 6 and having a cage winding composed of an end ring 7 disposed on both end surfaces thereof and a conductor bar (not shown). A squirrel-cage winding composed of the end ring 7 and a conductor bar (not shown) is formed by die casting of aluminum or the like. Further, the end ring 7 has an internal fan (blade blade) for internal cooling. 8 are integrally formed.

[0005] The rotating shaft 6 includes end brackets 2A and 2B.
Are rotatably held by bearings 4A and 4B. One end (the right end in the figure) of the rotating shaft 6 penetrates the end bracket 2B and protrudes outside.
An output shaft is formed, and a cooling fan (outer fan) 9 for external cooling is attached to a portion of the other end (the left end in the figure) of the end bracket 2A that projects through the end bracket 2A.

Reference numeral 10 denotes an end cover for covering the cooling fan 9, which is formed in a short dish-like cylindrical shape having one open side, and a portion corresponding to the bottom surface is provided with an intake port 10a for taking in outside air for cooling. And the open end is the end cover 10
Are formed so that when assembled to the end bracket 2A, a radial gap 10b is formed between the end bracket 2A and the outer diameter of the housing 1.

In this induction motor, the stator 3 is fitted and fixed in advance to the inner peripheral wall of the housing 1, and then the rotor 5 having the rotating shaft 6 is inserted into the stator 3 and rotated. On the shaft 6, bearings 4A in the end brackets 2A and 2B,
The end brackets 4A and 4B are fitted to both ends of the housing 1 by inlay fitting so that the end brackets 4B are fitted to each other, and the end brackets 4A and 4B are attached by a plurality of bolts (not shown).

When the cooling fan 9 is rotated by the rotor 5, outside air is sucked in from the air inlet 10a of the end cover 10 as indicated by an arrow a, and the sucked air flows from the gap 10b to the end cover 10 through the gap 10b. The cooling action is obtained by blowing out to the outside on the other end side and passing through the surfaces of the end bracket 2A, the radiation fins 1a of the housing 1, and the end bracket 2B.

On the other hand, inside the electric motor, when the rotor 5 rotates, the internal fan 8 rotates to generate a flow in the internal air, and the generated air flow is generated by the rotor 5, the end ring 7, and the stator. After passing through the coil 3B and the stator core 3A while cooling, the cooling is performed by passing through the inside of the end brackets 2A and 2B whose temperature rise is relatively lower than that of the housing 1.

As a known example of this type, for example, JP-A-61-251440 can be cited.

[0011]

The prior art described above does not provide sufficient consideration for improving the cooling efficiency, and has a problem in reducing the size and weight of the rotating electric machine. That is, in a general rotating electric machine, miniaturization and weight reduction are always a big proposition, and one of the ways to achieve this is to improve the cooling efficiency.In the conventional technology, a cooling fan is provided. However, since it cannot be said that the ventilation efficiency is improved by this, there is a problem that the size and weight of the rotating electric machine cannot be reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to increase the cooling efficiency of a cooling fan and to achieve a sufficiently small size and light weight. It is to provide an electric machine.

[0013]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rotating electric machine in which a cooling fan is used to cool an outer surface of a housing by cooling the outer surface of the housing by dividing a space between each blade blade of the cooling fan substantially in a radial direction. This is achieved by providing a shroud for forming a plurality of airflows and a fan guide for guiding the plurality of airflows divided by the shroud to an outer surface of the housing in a substantially independent manner.

In the present invention, as described above, the shroud is mounted between the blade blades to form two space portions in which the blade blades are substantially radially divided by the shroud. By making the shape of the shroud warped so that the sucked outside air leads to the housing side, in one space, the wind speed increases from the root side as the back side of the shroud to the rotating electric machine side. As it gradually increases in size, and in the other space, from the tip of the blade blade to the shroud side,
Wind speeds can be increased and air can flow along the shroud.

For this reason, the maximum wind speed in each space between the blade blades is smaller than that when the blade is not divided, but the average wind speed as a whole is larger than the average wind speed when the blade is not divided. And since the air volume between the blade blades is represented by the average air speed x the ventilation area, if the ventilation area is constant, the higher the average wind speed is, the larger the air volume will be. The average wind speed is increased, and the air volume can be increased.

Further, in the present invention, the function of effectively guiding the increased air volume to the housing as described above is obtained by the fan guide. Since the cooling fan according to the present invention has two space portions radially divided by the shroud, the outside air guided by each space portion is provided with the fan guide so that the outside air and the inner circumference side of the fan guide are separated. It is made to pass through two ventilation paths. One of the ventilation paths is formed by a space between the fan guide and the end bracket, and the other ventilation path is formed by a space between the fan guide and the end cover.

The fan guide has a shape that is warped in the opposite direction to the shroud so as to guide the outside air introduced by the cooling fan to the housing side. It is guided to the outer peripheral surface of the housing without mixing with each other.

As for the mounting of the fan guide and the end bracket, the fan guide and the end bracket are mounted so as to have a space between the inner circumference of the fan guide and the outer circumference of the end bracket that is substantially equal to the cross-sectional area of the ventilation path, thereby maintaining the two ventilation paths. It is led to the housing as it is.

The heat generating portion of the rotating electric machine is mainly a stator, which is located on the inner periphery of the housing. Therefore, the outside air cools better when it is passed near the surface of the housing. According to the present invention, the outside air guided by the fan guide has a function of passing air near the housing surface and a function of passing air above the outside air, and the outside air that has passed near the housing surface is heated by the heat and tends to rise. However, the other outside air that passes through the upper part of the outside air is cold and heavy, so that it prevents the rise of the outside air and can cool well by this effect.

According to the present invention, the configuration described above increases the air volume of the cooling fan and effectively ventilates the heat-generating portion, so that the cooling efficiency of the rotating electric machine can be surely increased. Can be miniaturized.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A rotary electric machine according to the present invention will be described below in detail with reference to the illustrated embodiments. FIG. 1 shows an embodiment in which the rotating electric machine according to the present invention is applied to an induction motor. The induction motor shown in FIG.
A so-called self-ventilation cooling system in which outside air is introduced from the intake port 10a of the end cover 10 by the rotation of the cooling fan 9 attached to the housing 1 and the introduced outside air passes through the outer surface of the housing 1 to obtain a cooling function. This is the same as the prior art shown in FIG. 7 in this respect.

In FIG. 1, 9A is a shroud, 9B is a blade blade, 11 is a fan guide, and the others are the same as the conventional example shown in FIG. Therefore, the same or equivalent parts as those in the conventional example of FIG. 7 are denoted by the same reference numerals, and detailed description thereof will be omitted.

First, the shroud 9A as a whole
The brim wide hat has a brim-like shape with only the brim portion cut out in a ring shape, and is made to be attached to the blade blade 9B. At this time, especially in the enlarged view of FIG. 2 and the front view of FIG. As can be clearly seen, a plurality of blade blades 9B extending radially from the center of the cooling fan 9
Between the blades 9B of the shroud 9A at this time.
2, the surface of the blade blade 9B is divided into two portions arranged in a diagonal outer peripheral direction, and two spaces C and D are formed between the blade blades 9B. Position.

Thus, the flow of the outside air sucked from the intake port 10 a of the end cover 10 is reduced by the cooling fan 9.
When passing through the blade blades 9B, the blades 9B are radially divided by the space portions C and D between the blade blades 9B, so that the speed of the airflow passing through these space portions C and D is increased. Like that.

The cross-sectional shape of the shroud 9A in the circumferential direction is, as shown in FIGS. 1 and 2, from the tip side (the intake port 10a side) to the base side (the end bracket 2A side) of the blade blade 9B. It is made into a so-called bellmouth shape that gradually curves outward as it goes toward. Here, the bellmouth is the mouth of a western bell with a widened tail.

Thus, the outside air that has passed through the space of the blade blade 9B flows along the shape of the shroud 9A, thereby giving directionality to the housing 1 side. When the cooling fan 9 is formed by casting or resin, the shroud 9A can be integrally formed as a whole, including the blade blade 9B.

Next, as a whole, the fan guide 11 is formed in such a shape that the bottom of a flat bowl is removed to form a circular opening and only the outer peripheral portion is formed. Inside the cooling fan 9 and end bracket 2
A is attached to the end bracket 2A by the support member 11a so as to be positioned between the end brackets 2A. The support member 11a also serves as a support for the end cover 10.

The mounting position of the fan guide 11 at this time is, as clearly shown in FIG. 1 and particularly FIG. 2, the end of the opening corresponding to the bottom portion of the shroud 9.
A is opposed to the outer peripheral end portion of the end cover 10A, and is slightly apart from each other in a range where the two end portions do not contact each other in the axial direction. The gap 10b is formed so as to reach the gap 10b formed between the gap 10b and the outer diameter of the first gap, and to define the inside of the gap 10b so that another gap 10c is formed.

The fan guide 11 protrudes from the housing 1 toward the cooling fan 9 and warps in the opposite direction to the shroud 9A so as to guide the outside air introduced by the cooling fan 9 to the housing 1. It has a shape.

As a result, the outside air having a direction directed toward the housing 1 is
Since there are two spaces divided in the axial direction by the shroud 9A, the outside air guided by each space is
The fan guide 11 passes through two ventilation passages on the outer peripheral side and the inner peripheral side.

One air passage is a space interposed between the fan guide 11 and the end bracket 2A, and the other air passage is a space interposed between the fan guide 11 and the end cover 10.

The fan guide 11 guides the outside air introduced by the cooling fan 9 to the housing 1 side.
Since the shroud 9A has a shape that is warped in the opposite direction, the two outside airs on the outer peripheral side and the inner peripheral side of the fan guide 11 are guided toward the housing 1 without being mixed with each other.

At this time, the fan guide 11 and the end bracket 2A are mounted by the support member 11a as described above. Here, a ventilation path is provided between the inner circumference of the fan guide 11 and the outer circumference of the end bracket 2. By mounting such that the gaps 10b and 10c having substantially the same cross-sectional area are formed, it is possible to guide the outside air to the housing 1 side while keeping the ventilation passage double.

The main heat generating portion of such an induction motor is the stator 3, which is located on the inner periphery of the housing 1. It is better to let it flow and it will cool down.

By the way, according to this embodiment, as a result of the directionality given by the shroud 9A and the fan guide 11, the outside air taken in from the intake port 10a is converted into the inside air passing near the housing surface indicated by the arrow B. It has a double cooling air configuration divided into a flow and an outside air flow indicated by an arrow A.

The temperature of the inside airflow that has passed near the surface of the housing 1 rises due to the heat generated by the stator 3, the specific gravity decreases, and the airflow tends to move away from the surface of the housing 1.
However, the inner air flow is covered by the outer air flow, and the outer air flow has a large specific gravity because the temperature remains low, and acts to suppress the spread of the inner air flow. As a result, according to the above embodiment, a sufficient cooling effect can be obtained.

Next, the operation of the above-described embodiment and the flow of air associated therewith will be described in comparison with the prior art.
This will be described in more detail. When electric power is supplied to the electric motor and the rotor 5 rotates, the cooling fan 9 also rotates, thereby causing the end cover 10 to rotate as shown in FIGS.
The outside air is sucked from the intake port 10a of the air conditioner, and the sucked air is blown by arrows A,
And as shown by arrow B, it is guided to the housing 1 side.

At this time, when air passes between the blade blades 9B, there is nothing in the blade blades 9 in the prior art, as shown in FIG. Looking at the wind speed distribution, the characteristic curve V
As shown by the arrow, the low wind speed is low on the air inflow side of the blade blade 9, that is, on the intake port 10a side, and gradually increases from there toward the housing 1 side, and reaches the maximum wind speed Vb on the housing 1 side. As a result, the average wind speed in the space E becomes a value indicated by a dashed line.

On the other hand, in the embodiment of FIG. 1, as described above, the space between the blade blades 9B is divided into two spaces C and D by the shroud 9A.
Has a blade section 9B whose sectional shape viewed in the circumferential direction.
End bracket 2 that is the base from the air inflow end side
It is formed in an outwardly curved shape so as to spread toward the position near A.

Therefore, as shown by arrows A and B,
The air flowing along the shroud 9A in the space D
As the wind speed gradually increases from the root side of the shroud 9A to the end bracket 2A side, the space C
However, from the air inflow end side of blade blade 9B, shroud 9
As it reaches the outer peripheral side of A, the wind speed gradually increases.

As a result, as shown in FIG. 4, in each of the space portions C and D, a wind speed distribution as shown by a characteristic curve V ′ and a characteristic curve V ″ is obtained, and these characteristic curves V ′ and V ″ are obtained.
Is the average wind speed indicated by the alternate long and short dash line.

From these figures, it can be seen that the maximum wind speed Va in the above embodiment is smaller than the maximum wind speed Vb in the prior art, but the average wind speed is
It can be seen that the average wind speed of the prior art without the shroud 9A is larger than that.

By the way, the air volume between the blade blades 9B in such a centrifugal fan is represented by an average wind speed × a ventilation area. Therefore, assuming that the ventilation area (corresponding to the axial length of the blade blade in this case) is constant, the higher the average wind speed, the larger the air volume can be obtained.Therefore, the air volume in the above embodiment is smaller than that of the prior art. It turns out that it is obtained more than an air volume.

Therefore, according to this embodiment, by providing the shroud 9A, the average wind speed of the air flow in each of the spaces C and D is increased, and as a result, the amount of cooling air is increased and the cooling effect is ensured. The size and weight of the rotating electric machine can be sufficiently reduced in combination with the improvement of the cooling efficiency by the above-described dual cooling air configuration.

FIG. 5 shows another embodiment of the present invention. In this embodiment, as shown, the outer peripheral portion of the shroud 9A in the embodiment of FIG. 1 is expanded, and FIG. As described above, the shroud 9A is integrated with the fan guide 11 to form a fan guide / shroud 9C.

The shroud 9C, which also serves as a fan guide,
As the name implies, it has both a function as a fan guide and a function as a shroud. Specifically, the space between each blade blade 9B is divided into two spaces C and D, and the cooling fan 9
Acts as a shroud for dividing the outside air introduced into the inside air flow indicated by the arrow B and the outside air flow indicated by the arrow A, and guides these air flows to the housing 1 side without being mixed with each other. It works as a.

Therefore, according to the embodiment shown in FIGS. 5 and 6, the improvement of the cooling efficiency by the increase of the air flow and the improvement of the cooling efficiency by the double cooling air structure are surely obtained. In addition to being able to achieve sufficient weight reduction
According to this embodiment, it is possible to reliably reduce the cost by reducing the number of parts.

In the above embodiment, the shroud 9A disposed between the blade blades 9B is formed so that the space portions C and D have substantially the same volume.
Although an example in which one is provided at an intermediate position in the axial direction of B is shown, a plurality of shrouds are provided depending on the axial length of the blade blade 9B, and the space between the blade blades is formed by the plurality of shrouds. If the average wind speed is increased by forming a plurality in the axial direction and the air volume is further increased, it is possible to further improve the cooling efficiency.

[0049]

According to the present invention, a shroud disposed at an intermediate position in the axial direction is provided between each blade blade of the cooling fan, the shroud increases the average wind speed between each blade blade, and reaches the outer periphery of the housing. By increasing the amount of air and allowing the outside air, which has been given directionality by the fan guide, to flow twice around the outer periphery of the housing, effective cooling of the heat generating part can be obtained. There is an effect that the size can be reliably reduced and the size and weight can be sufficiently reduced.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional side view showing an embodiment in which the present invention is applied to an induction motor.

FIG. 2 is a partially enlarged sectional view of one embodiment of the present invention.

FIG. 3 is a front view showing a cooling fan according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a wind speed distribution between blade blades of a cooling fan in one embodiment of the present invention.

FIG. 5 is a partial cross-sectional side view showing another embodiment of the rotating electric machine according to the present invention.

FIG. 6 is a partially enlarged sectional view of another embodiment of the present invention.

FIG. 7 is a partial cross-sectional side view illustrating an example of a rotating electric machine according to the related art.

FIG. 8 is an explanatory diagram showing a wind speed distribution between blade blades of a cooling fan according to a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 1a Radiation fin 2A, 2B End bracket 3 Stator 3A Stator iron core 3B Stator coil 3C Air gap 4A, 4B Bearing 5 Rotor 6 Rotating shaft 7 End ring 8 Inner fan 9 Cooling fan 9A Shroud 9B Blade blade 9C Fan guide Shroud 10 End cover 10a Inlet 10b, 10c Ventilation outlet 11 Fan guide

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor ▲ Taka ▼ Yoshihiro Tadashi 502, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratory, Hitachi, Ltd. (72) Inventor Asashi Yamada 7-1-1 Higashi Narashino, Narashino-shi, Chiba No. 1 Hitachi, Ltd.Industrial Equipment Division (72) Inventor Hiromitsu Tomiku 71-1 Higashi Narashino, Narashino City, Chiba Prefecture Hitachi, Ltd.Industrial Equipment Division (72) Inventor Tsuneo Sekine Kanda Surugadai, Chiyoda-ku, Tokyo 4-6, Hitachi, Ltd. (72) Izumi Shimizu, Inventor 4-6-6, Kanda Surugadai, Chiyoda-ku, Tokyo Tokyo, Japan (72) Matsushita Ihara 4-6-6-Kanda, Surugadai, Chiyoda-ku, Tokyo Stock (72) Inventor Toshifumi Suzuki 7-1-1 Higashi Narashino, Narashino City, Chiba Prefecture Hitachi, Ltd.Industrial Equipment Division (72) Inventor Yukio Endo 4-6-1 Kanda Surugadai, Chiyoda-ku, Tokyo Hitachi, Ltd. (72) Inventor Kaoru Ogawa 7-1-1, Higashi-Narashino, Narashino-shi, Chiba Co., Ltd. Hitachi, Ltd.Industrial Equipment Division

Claims (2)

[Claims] 1. A rotating electric machine in which the outer surface of a housing is cooled by ventilating an outer surface of a housing with a cooling fan, wherein a space between each blade blade of the cooling fan is divided substantially in a radial direction to form a plurality of air flows. A rotating electric machine, comprising: a shroud; and a fan guide for guiding a plurality of air flows divided by the shroud to an outer surface of a housing in a substantially independent state. 2. The rotating electric machine according to claim 1, wherein the shroud and the fan guide are integrally formed.