JP3132273B2 - Rotating electric machine - Google Patents

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 relatively small-capacity general-purpose induction motor using a light alloy or resin for a housing.

[0002]

2. Description of the Related Art As a rotating electric machine such as a general-purpose induction motor having a relatively small capacity, a rotating electric machine having a structure as shown in FIG. 9 has been generally used.

In FIG. 9, reference numeral 1 denotes a housing, which is also called a frame or a frame. The housing 1 is formed in a substantially cylindrical shape by casting an iron-based material such as cast iron, and forms a casing of the rotating electric machine. 1a is a radiation fin which is integrally cast with the housing 1 and is radially formed on the outer periphery thereof.

[0004] Reference numerals 2A and 2B denote end brackets, also referred to as bearing brackets, which are attached to both ends of the housing 1 by spigot fitting.

Reference numeral 3 denotes a stator, which is a stator core 3a made of a laminated body of silicon steel plates, and a stator wound around a plurality of slots provided on an inner peripheral portion of the stator core 3a. And a coil 3b. Reference numeral 5 denotes a rotor, and a rotating shaft 6
And the rotating shaft 6 is rotatably held by the bearings 4A and 4B of the end brackets 2A and 2B.
The rotor 5 located inside is configured to rotate. In such a rotating electric machine, the stator 3 is inserted into the inside of the housing 1 in advance and attached to the inner peripheral wall thereof. Then, the rotor 5 is inserted into the stator 3 and The end brackets 2A and 2B are fitted to both ends of the housing 1 by spigot fitting so that the bearings 4A and 4B are fitted, and are fixedly attached to the housing 1 by a plurality of bolts (not shown). Has become.

The rotating shaft 6 has one end (right side in the figure) inserted through the bearing 4B of the end bracket 2B and protrudes to the outside to form an output shaft, while the other end (left side) has 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. And this end cover 10
The opening 10a for taking in outside air with the outside fan 9
(Hereinafter, referred to as a ventilation inlet). The opposite side of the opening 10a is formed in an open cylindrical shape or an irregular cylindrical shape, so that a radial gap 10b is provided between the end bracket 2A and the outer diameter portion of the housing 1.
Is formed.

Therefore, when the outer fan 9 is rotated by the rotor 5, the outside air is sucked in from the ventilation inlet 10a of the end cover 10 and blown out from the gap 10b, whereby the end bracket 2A and the housing 1
And outside air is passed through the outer surface of the end bracket 2B,
A cooling effect is obtained. The rotor 5 is mounted in the housing 1 of the rotating shaft 6 at a position facing the stator 2. The rotor 5 is provided with a secondary conductor bar (not shown) and an end ring 7. And an internal cooling fan 8 (hereinafter, referred to as an integral part)
(Referred to as an inner fan). Fan 8
Is composed of a plurality of blade blades protruding in the axial direction from both end surfaces of the end ring 7 so as to ventilate inside the electric motor so as to obtain a cooling action.

That is, when the rotor 5 rotates, the inner fan 8 and the outer fan 9 also rotate, and the rotation causes the outside air to flow from the ventilation inlet 10a of the end cover 10 to each end bracket 2A, housing The outside air is passed through the outer surfaces of the first bracket 1 and the end bracket 2B to obtain cooling. Further, inside the electric motor, the air flow generated by the inner fan 8 passes through the rotor 5, the end ring 7, the stator coil 3b, and both end faces of the stator core 3a while cooling, and then the housing 1 In comparison, cooling is performed when passing through the end brackets 2A and 2B where the temperature rise is relatively low.

[0010]

The prior art described above cannot be said to take into consideration the light metalization and non-metalization of the housing, and has the following problems.

In the case where it is strongly demanded to reduce the size and weight of the rotating electric machine, aluminum or aluminum alloy material (having a specific gravity of about 1/3 of steel and having a good thermal conductivity) is used as a material for the housing.
Young's modulus is about 1/3, non-heat is about 2 times, thermal conductivity is about 3
There is a method that uses a light metal such as a double metal and transmits heat generated inside the rotating electric machine to the housing to improve cooling, thereby achieving a small and lightweight rotating electric machine.

On the other hand, there is a method in which a synthetic resin such as phenol or epoxy (the Young's modulus of a simple substance is about 1/100 of steel) or the like is used as a material of the housing to reduce the weight.

However, the use of any material has a problem that the Young's modulus is as small as about 1/3 or less of the iron-based material, and the strength is reduced. Pressing or baking
When the stator core is mounted on the housing by fitting, after mounting
Displacement occurs inside the stator core, causing magnetic noise
There was a problem that sound was generated. The present invention has been made in order to solve the above-mentioned problems, and secures the rigidity of the housing, and can be easily made into a light alloy or nonmetal by using an aluminum alloy or a synthetic resin such as phenol or epoxy. as size and weight reduction can be sufficiently obtained by improving the performance and after mounting the stator core to the housing
The internal noise of the stator core to reduce magnetic noise
The purpose is to provide a rotating electric machine.

A rotating electric machine according to the present invention represented by an induction motor generally transmits power to a load by means of a belt. When the belt is hung, a lateral pull load is applied to the rotating shaft of the rotating electric machine. This lateral pulling load acts on the end bracket and the housing that constitute the rotating electric machine with the bearing mounted on the rotating shaft as a fulcrum. When the state is analyzed by a finite element method or the like, the largest stress acts on the tip of the housing cylindrical portion and the base of the foot of the foot used for installing the rotating electrical machine due to the lateral pulling load. At this time, when an aluminum alloy or a resin is used as a material of the housing, mechanical strength (such as Young's modulus) is lower than that of an iron-based material. On the other hand, since the lateral pulling load is determined by the transmission torque, the stress value acting on each part is constant even if the material of the housing changes. Therefore, when the material of the housing is changed to an aluminum alloy or a synthetic resin such as phenol or epoxy, the displacement increases because the Young's modulus is small. When the displacement increases, there is a possibility that the rotating electric machine cannot be used normally.

In view of the above, the housing according to the present invention is to reduce the displacement to a permissible range by making the Young's modulus of the portion where the stress is highest and the displacement occurs as high as possible with respect to other portions.

[0016]

SUMMARY OF THE INVENTION A housing of a rotating electric machine according to the present invention is a housing of a housing on which a stator core is mounted.
The Young's modulus of the cylinder is smaller than the Young's modulus of the stator core.
And at least the displacement due to the lateral pulling load is within a predetermined range.
The stator core is not installed so that
Of the cylindrical part of the housing and the foot of the foot
Young's modulus of the housing in which the stator core is mounted
The configuration is such that it is larger than the Young's modulus of the cylindrical portion .

Next, the reason for limiting the range for increasing the Young's modulus will be described.

If the cylindrical portion of the housing on which the stator core is mounted has mechanical strength equal to or higher than that of the stator core (laminated silicon steel sheet), the stator core is press-fitted or shrink-fitted. As a result, displacement occurs in the inner diameter portion of the stator core after mounting. The occurrence of this displacement causes magnetic noise.

However, if the strength of the cylindrical portion is lower than that of the stator core, displacement occurs on the outer periphery of the housing and no displacement occurs on the inner diameter portion of the stator core.

Needless to say, the purpose of increasing the Young's modulus of the foot is to improve the strength of the foot.

[0021]

In the housing according to the present invention, the stress is highest and the Young's modulus of the portion where the displacement occurs is made as high as possible with respect to other portions, so that the displacement is reduced to an allowable range.

[0022]

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. In FIG. 1, reference numeral 11 denotes a metal lath, and the other components are the same as those of the conventional example described with reference to FIG.

In this embodiment, the housing 1 is made of an aluminum alloy material having good heat conductivity by die-casting with good productivity. At this time, the metal lath 11 is formed integrally at the same time.

Next, the metal lath 11 in this embodiment will be described.
The housing 1 having the above will be described in more detail with reference to FIGS.

First, the metal lath 11 has a shape shown in FIG. 4 and extends from the end to the tip of the stator core except for a cylindrical portion where the stator core is mounted near the center of the housing 1 as shown in FIG. Insert the cylinder into which the stator core is not mounted. Then, it is formed integrally with the housing 1 by die casting with good productivity. Therefore metal lath 1
In other words, the cylindrical portion on which the stator core is mounted is made of only an aluminum alloy material.

FIG. 3 is an external view of the housing according to the present invention as viewed from the front. The metal lath 11 is inserted between the outer diameter and the inner diameter of the housing 11 as shown in the figure.

Next, an embodiment of the present invention in which a resin is used as a main material of the housing will be described with reference to FIG.

In the figure, the reinforcing fibers 12 are three-dimensionally reinforced reinforcing fiber materials such as carbon fibers. The rest is the same as the conventional example described with reference to FIG.

In this embodiment, the main material of the housing 1 is made of a lightweight synthetic resin such as phenol or epoxy resin and a composite material of a hardening material such as quartz or sand. At this time, the reinforcing fibers 12 are integrally formed at the same time.

Next, the housing 1 having the reinforcing fibers 12 in this embodiment will be described in more detail with reference to FIGS.

First, as the reinforcing fiber 12, for example, carbon fiber reinforced in the shape shown in FIG. 8 in three dimensions in the vertical, horizontal and longitudinal directions is used. As shown in FIG. 6, this reinforcing fiber 12 is inserted into a cylindrical portion of the housing 1 where the stator core from the end to the tip is not mounted, except for the cylindrical portion near the center of the housing 1 where the stator core is mounted. I do.
And it is formed integrally with the housing 1 by injection molding.
Therefore, the cylindrical portion without the reinforcing fiber 12 is composed of only the resin material.

Next, the operation and effect of this embodiment will be described.

The rotating electric machine according to the present invention represented by an induction motor generally transmits power to a load by means of a belt. When the belt is hung, a lateral pulling load is applied to the rotating shaft of the rotating electric machine. This lateral pulling load acts on the end bracket and the housing that constitute the rotating electric machine with the bearing mounted on the rotating shaft as a fulcrum. When the state is analyzed by a finite element method or the like, the largest stress acts on the tip of the housing cylindrical portion and the base of the foot of the foot used for installing the rotating electrical machine due to the lateral pulling load. At this time, if a synthetic resin such as an aluminum alloy or phenol or epoxy is used as the material of the housing, the mechanical strength (such as Young's modulus) is lower than that of an iron-based material such as cast iron. On the other hand, since the lateral pulling load is determined by the transmission torque, the stress value acting on each part is constant even if the material of the housing changes. Therefore, when the material of the housing is changed to aluminum alloy or resin, the displacement increases because the Young's modulus is small. When the displacement increases, there is a possibility that the rotating electric machine cannot operate normally, for example, the stator comes into contact with the rotor.

Therefore, in the housing according to the present embodiment, the Young's modulus of the portion where the displacement occurs is made as high as possible with respect to the other portions so that the strength is improved and the displacement is reduced to an allowable range. That is, when the material constituting the housing is made of a material having a lower strength than an iron-based material such as an aluminum alloy or a synthetic resin such as phenol or epoxy, a measure is taken to improve the strength and rigidity.

Next, the reason for limiting the range for increasing the Young's modulus will be described.

If the cylindrical portion of the housing in which the stator core is mounted has mechanical strength equal to or greater than that of the stator core (laminated silicon steel sheet), the stator core is press-fitted or shrink-fitted. After the mounting, displacement occurs in the inner diameter portion of the stator core due to the press fitting allowance and the shrink fitting allowance of both. When this displacement occurs, the imbalance in the gap between the stator and the rotor increases, and as a result, the load applied to the bearing increases and magnetic noise increases. However, if the strength of the cylindrical portion is lower than that of the stator core, displacement occurs on the outer periphery of the housing and no displacement occurs on the inner diameter portion of the stator core.

The construction as described in the above embodiments not only compensates for the mere strength defect of the material used for the housing, but also makes it compact, lightweight, has high assembly accuracy, low vibration and noise, and has high reliability. A rotating electric machine can be provided.

It is clear that if the above-mentioned method is adopted for the foot portion of the housing, the foot portion can be easily reinforced, and a detailed description thereof will be omitted.

According to this embodiment, the following effects can be obtained.

1. It is possible to make up for the weakness of the strength of the aluminum alloy or the resin, which is weak, by a simple method. As a result, the rigidity of the housing can be improved.

2. A small and lightweight rotating electric machine can be provided.

3. It is possible to provide a rotating electric machine with high assembling accuracy and low vibration and noise.

4. As a result, a highly reliable rotating electric machine can be provided.

[0045]

According to the present invention, a housing for a rotating electric machine is provided.
To the housing cylinder to which the stator core is attached.
Of the stator core relative to the Young's modulus of the stator core, and
Minimize displacement due to lateral pulling load to a specified range
Housing without a stator core
Young's modulus at the tip of the cylinder
The cylindrical part of the housing on which the stator core is mounted
Since it is configured to be larger than's modulus, onto the can compensate the shortcomings of the strength of weak aluminum alloy or resin in a simple manner, it is possible to improve the rigidity of the resulting housing, assembling accuracy Therefore, an effect that a rotating electric machine with low vibration and low noise can be provided can be obtained.

[Brief description of the drawings]

FIG. 1 is an external partial cross-sectional side view of a rotating electric machine showing an embodiment of the present invention.

FIG. 2 is a detailed view of an external partial cross-sectional side view of the rotating electric machine showing one embodiment of the present invention.

FIG. 3 is an external front view of an aluminum alloy housing showing one embodiment of the present invention.

FIG. 4 is an external view of a metal lath showing one embodiment of the present invention.

FIG. 5 is a partial sectional side view showing the appearance of a synthetic resin housing rotating electric machine showing another embodiment of the present invention.

FIG. 6 is a detailed view of an external partial cross-sectional side view of a synthetic resin housing rotating electric machine showing another embodiment of the present invention.

FIG. 7 is an external front view of a synthetic resin housing showing another embodiment of the present invention.

FIG. 8 is an external view of a reinforcing fiber showing another embodiment of the present invention.

FIG. 9 is an external partial cross-sectional side view of a conventional rotating electric machine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Housing, 1a ... Radiation fin, 2A, 2B ... End bracket, 3 ... Stator, 3a ... Stator 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 ... metal lath, 12 ... reinforced fiber,

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Shunichi Ichiyama 7-1-1 Higashi Narashino, Narashino City, Chiba Prefecture Hitachi, Ltd. Industrial Equipment Division (56) References JP-A-55-29263 JP-A-1-275928 (JP, A) JP-A-58-26543 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02K 5/02 H02K 5/04

Claims (1)

(57) [Claims] 1. A substantially cylindrical rotary electric machine constructed by assembling end bracket at each end of the housing, the fixed
Fix the Young's modulus of the cylindrical part of the housing to which the iron core is attached.
Make it smaller than the Young's modulus of Sadako iron core, and at least
Also reduce the displacement due to the horizontal pulling load to a predetermined range.
As shown in the figure, the cylindrical part of the housing without the stator core
Fix the Young's modulus of the tip and foot at the root of the housing
From the Young's modulus of the cylindrical part of the housing on which the iron core is mounted
A rotating electric machine wherein the housing is made larger .