JPH0731090A - Rotating electric machine - Google Patents

Abstract

PURPOSE:To provide a small-sized, light-weight rotting electric machine in which a light metal such as aluminum alloy, etc., of a housing is employed and which is easily manufactured and has a sufficient strength. CONSTITUTION:A thinned space 12 is provided in a housing 11 of aluminum alloy, and a heat dissipating fin 1a, an outer peripheral wall 11a, an inner peripheral wall 11b and a partition wall 11c can be formed in uniform thicknesses. Thus, a fear of a shrinkage cavity, a defect of a cold shut is eliminated, and a small-sized, light-weight rotary electric machine in which a housing by a light metal die-casting can be manufactured and which has no irregularity in performance can be easily provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary electric machine such as an induction motor, and more particularly to a rotary electric machine suitable for a general-purpose induction motor having a relatively small capacity using a light metal for a housing.

[0002]

2. Description of the Related Art As a rotary electric machine such as a general-purpose induction motor having a relatively small capacity, a rotary electric machine having a structure shown in FIG. 6 has been generally used. In FIG. 6, reference numeral 1 denotes a housing, which is also called a frame or a frame, and is formed into a substantially cylindrical shape by casting an iron-based material such as cast iron, and constitutes a casing of a rotating electric machine. A heat radiation fin 1a is integrally cast with the housing 1 and is radially formed on the outer periphery thereof.

2A and 2B are end brackets, which are also called bearing brackets, which are attached to both ends of the housing 1 by means of spigot fittings.

Reference numeral 3 denotes a stator, which is a stator core 3a made of a laminated body of silicon steel plates, and this stator core 3a.
And a stator coil 3b wound around a slot portion provided in a large number on the inner peripheral portion.

Reference numeral 5 denotes a rotor, which is a rotating shaft.
6, bearings 4A, 4 of end brackets 2A, 2B
The rotary shaft 6 is rotatably held by B, so that the rotor 5 located in the stator 3 is rotated.

In such a rotary electric machine, the stator 3 is previously inserted into the housing 1 and attached to the inner peripheral wall thereof, and then the rotor 5 is inserted into the stator 3 to rotate the rotor. The shafts 6 are fitted with the bearings 4A and 4B, and the end brackets 2 are respectively attached to both ends of the housing 1.
A and 2B are spigot-fitted (fitted and joined) and fixedly attached to the housing 1 by a plurality of bolts (not shown).

One end side (right side in the figure) of the rotary shaft 6 is inserted through the bearing 4B of the end bracket 2B and protrudes to the outside to form an output shaft, but the other end side (left side) of the rotary shaft 6 is the end bracket 2A. An external cooling fan 9 (hereinafter, referred to as an external fan) is attached to a portion protruding from the bearing 4A. Reference numeral 10 denotes an end cover, which forms a cover for covering the outer fan 9. The end cover 10 is provided with an opening 10a (hereinafter referred to as a ventilation inlet) for taking in outside air with the external fan 9. Further, the opposite side of the opening 10a is formed into an open cylindrical shape or a deformed cylindrical shape, so that a ventilation outlet including a radial gap portion 1b is formed between the end bracket 2A and the outer diameter portion of the housing 1. To be formed.

Therefore, when the outer fan 9 is rotated by the rotor 5, the outside air is sucked from the ventilation inlet 10a of the end cover 10 and blown out from the gap 1b, whereby the end bracket 2A and Housing 1
And ventilating the outside air to the outer surface of the end bracket 2B,
It is designed to provide a cooling effect.

The rotor 5 is mounted in the housing 1 of the rotary shaft 6 at a position facing the stator 2. The rotor 5 has a secondary conductor bar (not shown) and an end ring 7. An internal cooling fan 8 (hereinafter referred to as an inner fan) is formed integrally with the end ring 7. The inner fan 8 is composed of a plurality of blade blades axially projecting from both end surfaces of the end ring 7 so as to ventilate the inside of the electric motor and obtain a cooling action.

That is, when the rotor 5 rotates, the inner fan 8 and the outer fan 9 also rotate with the rotation of the rotor 5, so that the outside air flows from the ventilation inlet 10a of the end cover 10 to the respective end brackets 2A and housings as indicated by arrows a. 1 and the outer surfaces of the end brackets 2B are ventilated to the outside air to obtain cooling. In addition, inside the electric motor, the air flow caused by the inner fan 8 passes through the rotor 5, the end ring 7, the stator coil 3b, and the stator core 3a while being cooled, and then passes through the housing 1. In comparison, the cooling is to be performed when passing through the portions of the end brackets 2A and 2B having a relatively low temperature rise.

[0011]

In the above-mentioned prior art, it cannot be said that consideration is given to making the housing light metal, and there are the following problems. When there is a strong demand for downsizing and weight reduction of rotating electrical machines, aluminum and aluminum alloy materials that are light and have good thermal conductivity (specific gravity is about 1/3 that of steel, specific heat is about 2 times, thermal conductivity is about There is a method of using a light metal such as (3 times) to well transfer the heat generated inside the rotating electric machine to the housing to improve the cooling, thereby making it possible to reduce the size and weight of the rotating electric machine.

As a method of manufacturing the housing in such a case, die-casting with high productivity is desirable, but since the housing of the rotating electric machine has not only a simple cylindrical portion but also a portion such as a rib, it is thick. Has many different parts. However, in die casting, this is likely to cause defects in casting, such as shrinkage cavities due to the difference in solidification rate of molten metal (molten metal), bubble entrapment cavities at the boundary of the molten metal, and so on. The conventional technology has a problem in that the characteristics of the housing made of a light metal such as an aluminum alloy material cannot be utilized.

The present invention has been made in order to solve the problems involved in making the housing of a rotary electric machine into a light metal.
An object of the present invention is to provide a rotating electric machine that does not have a risk of defects caused by die casting and can easily be made of a light metal such as an aluminum alloy material for a housing, and can be sufficiently reduced in size and weight by improving cooling performance. Is.

[0014]

SUMMARY OF THE INVENTION The above object is to provide a rotary electric machine constituted by assembling bearing brackets at both ends of a substantially cylindrical housing, and between the outer peripheral surface and the inner peripheral surface of the cylindrical portion of the housing. Is formed by forming a plurality of hollow spaces extending from one end of the housing to the other end.

[0015]

The plurality of lightening space portions formed in the housing work so as to make the wall thickness of each portion constituting the housing uniform. Therefore, the occurrence of casting defects in die casting can be prevented. Further, the space portion works to reduce the weight without reducing the strength of the cylindrical portion of the housing. Therefore, the size and weight can be reduced.

Further, since it is possible to use aluminum alloy or the like, the heat generated in the stator is well transmitted to the housing, and the temperature rise of the rotating electric machine can be sufficiently suppressed.

[0017]

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 present invention is applied to a general-purpose induction motor.
11 is a housing, 12 is a lightening space, and others are
This is the same as the conventional example described in FIG.

In this embodiment, the housing 11 is made of an aluminum alloy material having good thermal conductivity and is die-cast with good productivity. At this time, the hollow space 12 is formed at the same time. In addition, the radiation fins 1a for cooling are also integrally formed.

Next, the housing 11 having the lightening space 12 in this embodiment will be described in more detail with reference to FIGS. First, this lightening space 1
As shown in FIG. 2, 2 is formed in a substantially quadrangular (square) cross-sectional shape, and one end of the housing 11 is provided between the outer peripheral surface and the inner peripheral surface of the member forming the cylindrical portion of the housing 11. From the other end toward the other end in the axial direction. Therefore, as a result, the members forming the cylindrical portion of the housing 11 include the outer wall portion 11a and the inner wall portion 1
1b will be formed. At this time, the length of the lightening space 12 in the axial direction may be shorter than the length of the housing 11, but is preferably the same as the entire length.

Next, as shown in FIG. 3, a plurality of the lightening spaces 12 are arranged in a line along the circumferential direction of the member forming the cylindrical portion of the housing 11 over substantially the entire circumference. It is provided individually. Therefore, as a result, a part of the housing 1 is enlarged and shown in FIG.
The partition wall portion 11c is formed in addition to the outer peripheral wall portion 11a and the inner peripheral wall portion 11b in the member forming the cylindrical portion of No. 1, but at this time, in this embodiment, in the drawings, it is not so accurate. Although not shown, the dimension of the lightening space 12 is set to a predetermined value so that the outer peripheral wall 11a and the inner peripheral wall 11 are
b, and the thickness (wall pressure) of each wall portion of the partition wall portion 11c is set to be substantially the same, and the thickness of the heat radiation fin 1a is also set to be substantially the same.

Next, FIG. 5 shows another embodiment of the present invention.
In this embodiment, the inner peripheral wall portion 11b of the housing 11 is provided with a notch 11d which opens toward the center of the housing 11, and the other points are the same as those in the embodiments of FIGS.

Next, the function and effect of this embodiment will be described. As described above, the housing 11 shown in FIGS. 1 to 5 is manufactured by die-casting with high productivity using an aluminum alloy material having good thermal conductivity. At this time, the housing 11 according to this embodiment is used. According to the above, the thickness of the cylindrical portion and the radiation fins 1a is uniform, and as a result, shrinkage cavities due to the difference in the solidification rate of the hot water, bubble entanglement in the hot water boundary, etc. are suppressed,
It is possible to prevent the occurrence of defects that cause a decrease in strength.

In general, in die casting, high pressure is applied to the molten metal, so that the casting speed is high, and thus defects in which air bubbles are entrained are likely to occur. Therefore, as a preventive measure, usually, an optimal gate (injection port for hot water) is designed in accordance with the mold by a hot water flow simulation. It is more effective to improve the castability by devising the shape of the object. Therefore, according to this embodiment, the occurrence of bubble entrapment defects can be sufficiently suppressed, and the die-cast casting ensures a defect-free housing. Can be easily obtained.

By the way, in a rotary electric machine such as a general-purpose induction motor having a relatively small capacity, a method of manufacturing the light metal housing may be an extrusion method. In this case as well, the thickness of each part of the product is If it is uniform,
Since manufacturing of the mold and extrusion molding are facilitated, according to this embodiment, the precise housing 11 can be easily prepared by extrusion molding instead of die casting as described above.

Further, according to this embodiment, the housing 1
Since the thinned-out space 12 is provided in 1, it is possible to provide the same strength as that of the conventional technique while being thin, and thus it is possible to easily achieve the reduction in size and weight.

Next, the operation and effect of the embodiment shown in FIG. 5 will be described. As is conventionally known, in a rotary electric machine such as a general-purpose induction motor having a relatively small capacity, a press-fitting method is often used to mount the stator on the housing. In this case, however, the outer diameter of the stator core is made larger than the inner diameter of the housing by a predetermined value so as to give a crimp, and as a result, the housing is deformed by press fitting of the stator.

For this reason, in the prior art, it is necessary to process the spigot portion of the housing after press-fitting the stator into the housing. For this reason, cutting chips are formed in the inner stator, particularly near the stator coil. However, it has become difficult to prevent the entry of foreign matter such as.

However, in the embodiment shown in FIG. 5, the inner peripheral wall portion 11b of the housing 11 is provided with the notch 11e opening toward the center of the housing 11, and as a result, the stator 3 is placed inside the housing 11. When press-fitted into the housing 11, the stress applied to the inner peripheral wall portion 11b of the housing 11 is dissipated by deforming the notch 11d, and does not affect other parts of the housing 11.

Therefore, according to this embodiment, the risk of deformation of the housing 11 due to the press-fitting of the stator 3 can be eliminated, and as a result, the spigot portions are previously formed on both end surfaces of the housing 11. Also, the end brackets 2A, 2B will not be misaligned when mounted, and there is no fear of deterioration of reliability due to deterioration of insulation due to mixing of chips or the like, and there is no fear of variation in performance. It is possible to easily provide a lightweight electric motor.

In the above embodiment, the lightening space 1
Although the case where the cross-sectional shape of 2 is a square has been described, the object of the present invention can be achieved for the time being, for example, if a polygon other than a round shape and a square shape is used.

[0031]

According to the present invention, since the housing can be manufactured by die-cast casting with a light metal, the following effects can be obtained.

1. It is easy to manufacture, and there is no risk of shrinkage cavities or defects in the hot water, and a precise housing can be easily obtained.

2. It is possible to provide a small and lightweight rotating electric machine with the same strength as the conventional technology (it is possible to reduce the volume by about 30%).

3. The temperature rise of the rotating electric machine can be reduced.

4. Since there is no deformation of the housing after press-fitting the stator, it is possible to easily provide a rotating electric machine with uniform performance without deterioration in assembly accuracy.

[Brief description of drawings]

FIG. 1 is a side view with a partial cross section showing an embodiment of a rotating electric machine according to the present invention.

FIG. 2 is a side view with a partial cross section of a housing according to an embodiment of the present invention.

FIG. 3 is a front view of the housing according to the embodiment of the present invention.

FIG. 4 is a partially enlarged front view of the housing according to the embodiment of the present invention.

FIG. 5 is a partially enlarged front view of a housing according to another embodiment of the present invention.

FIG. 6 is a side view with a partial cross section showing a conventional example of a rotating electric machine.

[Explanation of abbreviations]

 1 Housing 1a Radiating fins 2A, 2B End bracket 3 Stator 3a Stator iron core 3b Stator coil 4A, 4B Bearing 5 Rotor 6 Rotating shaft 7 End ring 8 Inner fan 9 Outer fan 10 End cover 10a Vent 11 Housing 11a Outer periphery Wall part 11b Inner peripheral wall part 11c Partition wall part 12 Thinned space part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshinori Narige 7-1-1 Higashi Narashino, Narashino City, Chiba Prefecture Hitachi Narashino Factory

Claims (3)

[Claims] 1. A rotary electric machine configured by assembling end brackets at both ends of a substantially cylindrical housing, wherein one end of the housing is provided between an outer peripheral surface and an inner peripheral surface of the cylindrical portion of the housing. A plurality of lightening space portions extending from one portion to the other end portion are formed. 2. The rotary electric machine according to claim 1, wherein a cutout portion is formed in a wall portion located on the inner peripheral surface of the lightening space portion. 3. In the invention of claim 1 or 2,
A rotary electric machine characterized in that the cross-sectional shape of the lightening space portion is formed into a substantially rectangular shape, and the wall portion forming the lightening space portion is formed to have a substantially uniform thickness in all portions. .