JPH099532A - Motor - Google Patents

Abstract

PURPOSE: To provide a motor which produces a low magnetic loss and which is small in size and thin in thickness and, further, which has a high efficiency. CONSTITUTION: Stator windings 33b are applied to a stator core 33a having teeth 33c as toroidal windings. Notches 11 are provided in the backside parts of the teeth 33c and fluxes induced by the stator windings 33b are introduced into a rotor through the teeth 33c as shown by arrows 21. With this constitution, the leakage components of the fluxes induced in the stator can be reduced, so that the decline of a torque can be avoided and hence a small and thin motor with a high torque and a high output can be provided. Further, a power- saving-type motor with a high power factor can be provided.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art As a general-purpose induction motor having a relatively small capacity, a structure shown in FIG. 7 has been generally used. In FIG. 7, reference numeral 1 denotes a housing, also called a frame or a frame, which is made of a light alloy material such as cast iron or aluminum and has a substantially cylindrical shape, and constitutes an outer cover of the electric motor. Reference numeral 1a is a heat radiation fin, which is in the form of a strip extending in the axial direction, and is formed radially on the outer periphery of the housing 1 by integrally casting with the housing 1. Reference numerals 2A and 2B denote end brackets, which are also called bearing brackets. The bearings 4A and 4B are housed in the housing 1 and are attached to both ends of the housing 1 by spigot fitting.

A stator 3 is wound around a stator core 3a made of a laminated body of silicon steel plates and a plurality of slots (grooves) provided on the inner circumference of the stator core 3a. It is composed of a stator winding 3b. Reference numeral 5 denotes a rotor, which has a rotary shaft 6, which is end brackets 2A, 2
By being rotatably held by the B bearings 4A and 4B, it is configured to rotate at a predetermined position inside the stator 3 and at a position facing the stator 3. Then, in such a conventional electric motor, the stator 3 is inserted into the housing 1 in advance and attached to the inner peripheral wall thereof, and then the rotor 5 is inserted into the stator 3 and then the rotary shaft. 6, so that the bearings 4A and 4B are fitted to each other, the end brackets 2A and 2B are fitted to both ends of the housing 1, respectively, and a plurality of bolts (not shown)
It is adapted to be fixedly attached to the housing 1 and assembled.

One end (the right end in the figure) of the rotary shaft 6 is inserted through the bearing 4B of the end bracket 2A and protrudes to the outside,
Although forming the output shaft, the other end (left end) is projected from the bearing 4A of the end bracket 2A, and the external cooling fan 9 is attached to that portion. An end cover 10 forms a cover for covering the external cooling fan 9, and the end cover 10 is provided with a ventilation inlet 10a serving as an opening for taking in outside air by the external cooling fan 9. Further, the opposite side of the ventilation inlet 10a is formed into an open cylindrical shape or a deformed cylindrical shape, whereby a radial gap 10b is formed between the end bracket 2A and the outer diameter portion of the housing 1.
A ventilation outlet consisting of is formed. Therefore, when the external cooling fan 9 is rotated by the rotor 5, the outside air is sucked from the ventilation inlet 10a of the end cover 10 and is blown out from the gap 10b, whereby the end bracket 2A, the housing 1 and the end. Outside air is ventilated on the outer surface of the bracket 2B to obtain a cooling effect.

As described above, the rotor 5 is mounted in the housing 1 of the rotary shaft 6 at a position facing the stator 2, and the rotor 5 has a secondary conductor bar (not shown). An end ring 7 is provided, and an internal cooling fan 8 is formed integrally with the end ring 7.

The internal cooling fan 8 is composed of a plurality of blade blades axially projecting from both end faces of the end ring 7, and circulates air inside the electric motor to obtain a cooling action. . That is, the airflow generated by the internal cooling fan 8 flows while cooling both end surfaces of the rotor 5, the end ring 7, the stator winding 3b, and the stator core 3a, and then, relatively to the housing 1. Heat is obtained when passing along the inner surfaces of the end brackets 2A, 2B having a low temperature rise. A known example of this kind is, for example, JP-A-61-251440.
There is an official gazette.

By the way, miniaturization of an electric motor is a big subject, but especially when it is desired to reduce the axial dimension thereof, tooth portions are formed at equal intervals along the circumferential direction of the inner peripheral surface. A toroidal winding type stator in which a substantially cylindrical stator core is used and stator windings are separately wound around the yoke portions between the teeth of the stator core, so-called toroidal winding type stators. An electric motor using is proposed, for example, in Japanese Patent Application Laid-Open No. 55-139062. Therefore, in the prior art of FIG. 7 as well, the toroidal winding type stator is used. Therefore, as shown in FIG. 8, the stator winding 3b includes the teeth (teeth) and teeth of the stator core 3a. In the slot portion (groove portion) between them, the yoke portion is wound in a toroidal shape.

As a result, the stator winding 3b is also wound around the outer peripheral surface of the stator core 3a, so that the stator 3 is fixed to the inside of the housing 1 by avoiding this portion. As described above, a plurality of fixing members 1b are provided on the inner peripheral wall of the housing 1, and the outer peripheral surface of the stator core 3a is fitted and attached to this. By using this toroidal winding type stator, winding crossover at both axial end surfaces of the stator core 3a can be reduced, and the swelling dimension of the coil end can be suppressed. The axial dimension can be reduced, and a so-called thin electric motor can be obtained.

[0009]

Although the above-mentioned prior art can achieve some results in downsizing, particularly thinning of the electric motor, consideration is given to an increase in leakage flux in the toroidal winding type stator. However, there is a problem that the characteristics of the electric motor are deteriorated, such as an increase in exciting current.

That is, in the conventional toroidal winding type stator, in the magnetic flux generated by energizing the winding, a considerably large amount of components leak to the outside of the stator without interlinking with the rotor. The leakage does not contribute to the generation of torque, and therefore deteriorates the characteristics of the electric motor.

An object of the present invention is to reduce the amount of magnetic flux leakage in the toroidal wire wound type stator, thereby suppressing the decrease in torque, achieving high torque, high output, and miniaturization and thinning. To provide the electric motor which did.

[0012]

The above object is to use a substantially cylindrical stator core in which tooth portions are formed at equal intervals along the circumferential direction of the inner peripheral surface, and the above-mentioned teeth of the stator core are used. In a motor provided with a toroidal winding type stator in which stator windings are separately wound around the yoke portion between the two parts, a yoke located on the outer peripheral side of the position where the teeth of the stator core are present. To the department
Providing a notch formed from the outer peripheral surface toward the inner peripheral surface,
The magnetic flux that goes in the circumferential direction along the vicinity of the outer peripheral surface of the yoke section is
This is achieved by being guided to the teeth by this notch. At this time, the notch may be left as it is, a non-magnetic metal material body may be provided therein, or a directional magnetic material may be provided.

[0013]

The cutout portion serves to locally increase the magnetic resistance of the path extending in the circumferential direction along the vicinity of the outer peripheral surface of the yoke portion at the outer peripheral portion of the groove portion. As a result, the magnetic flux is directed from the outer periphery of the iron core toward the teeth, and the saturation phenomenon of the magnetic flux density occurs in the vicinity of the notch, which makes it difficult for the magnetic flux to pass through the notch. It is made to go to the teeth part in the center of the iron core where it is easy to do. As a result, the magnetic flux component leaking to the outside of the stator core is suppressed, and most of the generated magnetic flux flows into the rotor core,
The magnetic flux can be oriented so as to interlink with the rotor windings.

When the material of the cutout portion is made of a non-magnetic material as described in claim 2, the magnetic flux cannot pass through the cutout portion, the same action as that of the cutout portion is produced, and the leakage magnetic flux is generated. Decrease. When the material of the cutout portion is made of a directional magnetic material as in claim 3, the direction in which the magnetic flux passes is restricted to the rotor side, and the direction of the magnetic flux that interlinks with the rotor. Can be attached. As a result, according to the present invention, the leakage of the magnetic flux can be reduced, and the component contributing to the torque generation is increased accordingly, so that the reduction of the torque can be suppressed even if the outer diameter of the stator is reduced. And then
Further miniaturization can be obtained.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An electric motor according to the present invention will be described in detail below with reference to embodiments shown in the drawings. FIG. 1 shows an embodiment in which the present invention is applied to a general-purpose induction motor.
Is a stator, 33a is a stator core made of a laminated body of silicon steel plates, and 33b is a vacant space (slot part) between the teeth provided in the inner periphery of the stator core 33a. The stator winding is wound around the yoke. In addition, this Figure 1
The embodiment of the present invention shown in FIG. 7 looks the same as the conventional example shown in FIG. 7 in this figure, but this is the difference between the embodiment of the present invention and the conventional example. As shown in FIG. 2, the stator core 33a is provided with the cutout portion 11, whereas in the prior art, as is apparent from FIG. 8, the outer peripheral surface of the stator core 3 remains cylindrical. This is because the other configurations are the same as those of the conventional example shown in FIG.

First, referring to FIG. 9, the flow of magnetic flux in the conventional stator core 3a will be described. In FIG. 9, 20 is the magnetic pole at a certain moment of the rotating magnetic field appearing in the stator core. Represents a border. Then,
At the end portion 20 of this magnetic pole, as shown by the arrow 21, a magnetic flux is generated from the peripheral yoke portion of the stator core 3a toward the center, and this becomes the main magnetic flux that contributes to torque generation. At this time, at the end 20 of the magnetic pole, the arrow 22
As shown by, magnetic flux leaks to the outside of the stator core. As a result, in the prior art, the main magnetic flux 2
1 is reduced, and eventually there is a limit in terms of downsizing.

On the other hand, according to the embodiment of the present invention, as shown in FIG. 2, the notch portion 11 is provided, whereby the notch portion 11 is provided.
It is possible to reduce the leakage magnetic flux 22 and make most of the magnetic flux generated in the stator winding 3b the main magnetic flux. FIG.
Shows the details of FIG. 2, and in these figures,
Reference numeral 33c represents a tooth portion (groove portion), 33d represents a bottom portion of the tooth portion 33c, and 11 is a notch portion as described above. The notch portion 11 has a plurality of teeth portions 33c provided on the stator core 33a.
Of the plurality of teeth portions 33c in the portion where the end portion 20 of the magnetic pole appears, the stator core 33a is attached to the outer peripheral yoke side.
From the outer periphery to the center with a length and width larger than the main air gap size of the electric motor.

Next, the function of the cutout portion 11 will be described. Since the cutout portion 11 is provided on the path extending in the circumferential direction of the yoke portion of the stator core 33a, this path is closed, I try to make a detour inside. As a result, the magnetic flux flowing along this path is
Due to the high magnetic resistance appearing in the portion where 1 is present, as shown by the arrow 21, it is oriented toward the tip of the tooth portion 33c and in the direction interlinking with the rotor winding. Further, in the portion where the cutout portion 11 is present, the path of the magnetic flux is narrowed, so that a saturation phenomenon of the magnetic flux occurs. As a result, the magnetic flux becomes difficult to pass in the vicinity of the cutout portion 11. Easy to pass teeth bottom 33d
I will be directed to.

Therefore, according to the embodiments shown in FIGS. 1 to 3, the magnetic flux leaked to the outside of the stator core in the prior art can be prevented, and as a result, the magnetic fluxes shown in FIGS.
As shown by the arrow, most of the magnetic flux generated by the stator winding 33b can be the magnetic flux interlinking with the rotor winding as indicated by the arrow 21, and the characteristic is deteriorated. The size of the electric motor can be sufficiently reduced without being accompanied by the above.

In the above embodiment, the notch 11 has a constant width, that is, the stator core 3
Although the same has been described for the outer circumference and the inner circumference of 3a, it is even more effective if the width is wide at the outer circumference, narrow at the inner circumference, and formed in a tapered shape that widens outward. Also, the corners of the notch may be arcuate.

Next, FIG. 4 shows a second embodiment of the present invention. In the figure, 12 is a non-magnetic member made of, for example, austenitic stainless steel, aluminum or aluminum alloy, Other configurations are
This is the same as the embodiment described with reference to FIGS. This member 1
2 is a notch portion 11 in the embodiment shown in FIGS. 2 and 3.
Since the member 12 is a non-magnetic member, it is difficult for the magnetic flux to pass near the notch 11, so that the magnetic flux is directed toward the tooth bottom 33d which is easy to pass. To be done.

Therefore, according to the embodiment shown in FIG. 4 as well, the magnetic flux leaking to the outside of the stator core can be prevented, and as a result, the motor can be sufficiently miniaturized without deterioration in characteristics. Can be achieved. Even in the case of this embodiment, the shape and dimensions of the non-magnetic material that becomes the member 12 can be the same as those of the embodiment described with reference to FIGS. 2 and 3.

Next, FIGS. 5 and 6 show a third embodiment of the present invention. In the drawings, 13 is a member made of a directional magnetic material, which is made of, for example, a directional silicon steel plate. The magnetizing direction is such that the magnetizing direction is from the outer peripheral side to the inner peripheral side of the stator core 33a, and the magnets are inserted into the divided portions of the stator core 33a as shown in the figure.
In FIG. 6, the arrow 13a indicates the direction of easy magnetization of the member 13, whereby the magnetic flux is induced by the member 13 at the boundary of the magnetic poles of the stator core 33a as indicated by the arrow 21. Therefore, the magnetic flux leaking to the outside of the stator core can be blocked by this embodiment as well, and as a result, the size of the electric motor can be sufficiently reduced without deteriorating the characteristics. You can In addition,
Also in the case of this embodiment, the shape and dimensions of the member 13 can be the same as those of the embodiment described in FIGS. 2 and 3.

Therefore, according to the above-described embodiment, it is possible to reduce the leakage of magnetic flux, and as a result, it is possible to easily provide a small-sized and thin high-torque, high-output electric motor. Further, according to the above-mentioned embodiment, since the leakage magnetic flux can be reduced, the exciting current under the same torque is reduced, and the electric motor having a good power factor can be obtained.

[0025]

According to the present invention, the following effects can be obtained. 1. Since the leakage of the magnetic flux generated in the stator can be reduced,
Therefore, a large torque can be obtained, so that a high torque and high output electric motor can be provided. 2. Since the leakage magnetic flux can be reduced, it is possible to provide a power-saving electric motor with a good power factor.

[Brief description of drawings]

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

FIG. 2 is a partially enlarged perspective view of the stator according to the first embodiment of the present invention.

FIG. 3 is a partially enlarged view of a stator portion according to the first embodiment of the present invention.

FIG. 4 is a partially enlarged perspective view of a stator portion according to a second embodiment of the present invention.

FIG. 5 is a partially enlarged perspective view of a stator portion according to a third embodiment of the present invention.

FIG. 6 is a partially enlarged view of a stator portion according to a third embodiment of the present invention.

FIG. 7 is a partial cross-sectional side view showing a conventional example of an electric motor.

FIG. 8 is a partially enlarged perspective view of a stator portion according to a conventional example.

FIG. 9 is a partially enlarged perspective view of a stator portion according to a conventional example.

[Explanation of reference numerals] 1 housing 1a heat radiation fins 2A, 2B end brackets 3, 33 stators 3a, 33a stator cores 3b, 33b stator windings 33c teeth (grooves) 4A, 4B bearings 5 rotors 6 rotating shafts 7 End ring 8 Internal cooling fan 9 External cooling fan Outside 10 End cover 10a Ventilation port 10b Ventilation outlet 11 Notch 12 Member made of non-magnetic material 13 Member made of directional magnetic material 13a Magnetic flux of member made of directional magnetic material easy Direction 20 Magnetic pole end 21 Arrow indicating main magnetic flux, 22 Arrow indicating leakage magnetic flux

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukio Endo 4-6, Kanda Surugadai, Chiyoda-ku, Tokyo Inside Hitachi, Ltd. (72) Inventor Ryuichi Iwata 4, 6 Kanda, Surugadai, Tokyo Hitachi, Ltd. (72) Inventor Takashi Yasuhara 7-1-1 Higashi Narashino, Narashino City, Chiba Prefecture Hitachi Industrial Co., Ltd. Industrial Equipment Division (72) Asahi Yamada 7-1 Higashi Narashino, Narashino City, Chiba Prefecture Hitachi, Ltd. Industrial Equipment Division

Claims (3)

[Claims] 1. A substantially cylindrical stator core in which teeth are formed at equal intervals along a circumferential direction of an inner peripheral surface, and a yoke portion between the teeth of the stator core is used. In a motor having a toroidal winding type stator in which stator windings are separately wound, in a yoke portion on the outer peripheral side of the position where the tooth portion of the stator core exists, from the outer peripheral surface, A notch portion formed toward the inner peripheral surface is provided, and magnetic flux heading in the circumferential direction along the vicinity of the outer peripheral surface of the yoke portion is guided to the tooth portion by the notch portion. An electric motor characterized by. 2. The electric motor according to claim 1, wherein the cutout portion is provided with a non-magnetic metal material. 3. The invention according to claim 1, wherein a directional magnetic body is provided in the cutout portion, and the direction of easy magnetization of the directional magnetic body is a direction from an outer peripheral side to an inner peripheral side of the stator core. An electric motor characterized by being configured as follows.