JP2000253603A - Stator core for induction motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the efficiency of an induction motor even when the gap between the stator core and rotor core of the motor is reduced. SOLUTION: A stator core 8 for induction motor is formed in a circular- arcuate shape by making the radius of curvature of the core 8 smaller than the inside radius of a stator so that the surface areas of the front end sections of teeth-section cores 5 which become the inner peripheral side of the core 8 which a rotor core 2 faces with a gap 6 in between may be increased and the central one of the magnetic fluxes generated in the cores 5 by the windings wound around the cores 5 may first reach the rotor core 2 and the outermost ones of the magnetic fluxes may last reach the core 2. Therefore, the substantial magnetic flux density in the gap 6 is reduced and the efficiency of an induction motor can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an iron core of an electric motor used for a small condenser motor or the like and capable of improving the motor efficiency.

[0002]

2. Description of the Related Art FIG.
And those shown in FIG. 9 were generally known. Hereinafter, the configuration will be described with reference to FIGS.

As shown in the drawing, a stator core 103 having a plurality of tooth cores 102 in a radial direction inside a yoke core 101, and a gap ( A rotor iron core 105 is provided via an air gap) 104,
The rotor core 105 had a rotor groove 106 for casting a conductor.

[0004] The stator core 103 and the rotor core 105 are each laminated to a predetermined thickness, and a winding (not shown) is wound around the stator core 103 so that the rotor core 1
In the motor 05, a rotor shaft (not shown) is provided after the conductor is cast in the rotor groove 106, and the rotor shaft is rotatably provided inside the stator core 103 via the air gap 104 to constitute a motor.

[0005]

A stator iron core 103 and a rotor iron core 105 which constitute such a conventional motor.
In this case, the gap 104 between the stator core 103 and the rotor core 105 is usually formed to be 0.25 to 0.30 mm, but the efficiency of the motor is still insufficient.

Therefore, in order to improve the motor efficiency, it has been considered that the air gap is set to 0.10 to 0.15 mm. However, the increase in the harmonic torque is often larger than the increase in the torque due to the fundamental wave. There is a problem that the motor efficiency is reduced in most cases, and it is required to improve the motor efficiency.

SUMMARY OF THE INVENTION The present invention is to solve such a conventional problem, and to provide an iron core of a motor which can improve motor efficiency even when a gap between a stator iron core and a rotor iron core is reduced. With the goal.

[0008]

In order to achieve the above object, an iron core of a motor according to the present invention has a stator iron core having a rotor groove for casting a conductor, and a rotor iron core facing through a gap. Increases the surface area of the tip of the tooth core on the inner peripheral side of the core, and of the magnetic flux generated in the tooth core by the winding wound around the tooth core, the magnetic flux in the center part rotates first The radius of curvature is made smaller than the inner radius of the stator so that it reaches the iron core and arrives later toward the end, and is formed in an arc shape. ADVANTAGE OF THE INVENTION According to this invention, the iron core of the electric motor which can improve motor efficiency even if the air gap between a stator iron core and a rotor iron core is made small is obtained.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotor core having a rotor groove for casting a conductor. The radius of curvature is made smaller than the inner radius of the stator so as to increase the surface area, and the iron core of the electric motor is formed in an arc shape. The tip of the tooth core is formed in an arc shape with a smaller radius of curvature. This has the effect of increasing the surface area of the tip end of the toothed iron core facing the rotor iron core, reducing the substantial magnetic flux density and improving motor efficiency.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0011]

(Embodiment 1) As shown in FIGS. 1 to 3, a rotor core 2 in which a plurality of rotor grooves 1 for casting a conductor (not shown) are arranged in a ring shape is formed. Slots 4 into which windings (not shown) are inserted are arranged on the left and right inside the core core 3, a plurality of tooth cores 5 projecting in the inner diameter direction are provided, and the rotor core 2 The tooth tip 7 on the inner peripheral side, which is located on the opposite side, has a smaller radius of curvature than the inner radius of the stator and is formed in an arc shape to form the stator core 8.

The stator core 8 and the rotor core 2
After laminating to a predetermined thickness, a winding is wound around the stator core 8, and the rotor core 2 is provided with a rotating shaft (not shown) after casting a conductor in the rotor groove 1, A motor is configured by being rotatably provided inside the stator iron core 8 via the air gap 6.

In the above configuration, when a current is applied to the winding wound around the tooth core 5 of the stator core 8, the magnetic flux generated in the tooth core 5 is transferred to the rotor core 2 through the air gap 6. To reach. At this time, since the tip 7 of the tooth core 5 is formed in an arc shape so as to be smaller than the radius of curvature, the surface area of the tip 7 is increased as compared with the case where the tip 7 is formed flat. Thus, the magnetic flux is dispersed and the substantial magnetic flux density in the gap 6 is reduced.

In the above configuration, the magnetic flux generated in the tooth core 5 by the winding (not shown) wound around the tooth core 5 is applied to the tip 7 of each tooth core 5 and the rotor iron. Void 6 between cores 2
Reaches the rotor core 2 with a certain phase according to the magnetic flux at the center of the tip 7 of the tooth core 5 of the air gap 6 reaches the rotor core 2 first. The magnetic flux arrives at the rotor core 2 with a delay as the distance from the center of the tip 7 of the tooth core 5 toward the end increases.

The stator core 8 and the rotor core 2
Was laminated to 18 mm, formed into a condenser motor having four-pole windings, installed in a ventilation fan, and tested for performance.

[0016]

[Table 1]

The following characteristic results were obtained.

As described above, according to the motor of the first embodiment, it was possible to achieve an improvement of about 15% when judged comprehensively.

(Embodiment 2) As shown in FIGS. 4 and 5, the tip 7A of the toothed iron core 5A of the stator iron core 8A is formed in an arc shape having a radius of curvature smaller than the inner radius. The stator core 8A is formed by reducing the gap at the end in the leading direction with respect to the rotor rotation direction and increasing the gap at the end in the lag direction.

In the above construction, the magnetic flux density of each tooth of the magnetic flux generated in the tooth core 5A by the winding (not shown) wound around the tooth core 5A is approximately equal to the sine wave. It is formed to be a part.

The stator core 8A and the rotor core 2
Was laminated to 18 mm in the same manner as in Example 1, formed into a condenser motor having windings on four poles, assembled into a ventilation fan, and tested for performance.

[0022]

[Table 2]

The following performance results were obtained. As described above, according to the motor of the second embodiment, it was possible to achieve an improvement of about 10% by judging comprehensively.

(Embodiment 3) As shown in FIGS. 6 and 7, in the tooth iron cores 5B and 5C of the stator iron core 8B, the teeth iron cores 5B at both ends of which the respective poles are surrounded by short windings. Enlarged inner radius and widened gap, tooth core 5C other than both ends
The iron teeth of the stator teeth having different air gaps are alternately formed so as to reduce the inner diameter radius and the air gap.

In the above configuration, the magnetic flux generated in the tooth cores 5B and 5C by the windings 9 wound around the tooth cores 5B of the respective poles is transferred to the tip 7B of the tooth cores 5B and 5C and the rotor iron. Since the magnetic flux reaches the rotor core 2 with a certain phase for each slot according to the gap between the cores 2, the magnetic flux of the tooth core 5 </ b> B, which is wide in the gap, reaches the rotor core 2 first and the gap The magnetic flux of the narrow toothed iron core 5C reaches the rotor iron core 2 with a delay.

The stator core 8B and the rotor core 2
Was laminated to 18 mm in the same manner as in Example 1, formed into a condenser motor having windings on four poles, assembled into a ventilation fan, and tested for performance.

[0027]

[Table 3]

The following performance results were obtained. As described above, according to the motor of the third embodiment, it was possible to achieve an improvement of about 15% when judged comprehensively.

[0029]

As is apparent from the above embodiments, according to the present invention, a rotor core having a rotor groove for casting a conductor is in contact with an inner peripheral side of a stator core facing through a gap. The magnetic flux generated in the tooth core by the winding wound around the tooth core so as to increase the surface area of the tip of the tooth core becomes the rotor magnetic core first. And a smaller radius of curvature than the inner diameter of the stator is formed into an arc shape so as to reach the end with a delay toward the end, so that the substantial magnetic flux density of the air gap is reduced and the motor efficiency is improved. It is possible to provide an iron core of a motor that can be used.

Further, the stator tooth part iron is formed so that the waveform of the magnetic flux generated in the tooth part iron core by energizing the winding wound around the tooth part iron core becomes approximately a part of a sine wave. The leading end of the core is formed in an arc shape having a radius of curvature smaller than the inner radius, and a gap G at the end in the advancing direction with respect to the rotor rotation direction.
a, the gap Gb at the end in the lag direction is increased, and Ga
Since the molding is performed so that the ratio Ga / Gb of Gb and Gb becomes 1.01 to 1.02, the motor efficiency can be improved.

Further, in a stator iron core of a capacitor motor having two teeth having one tooth per phase and one tooth having the same pitch and the same tooth width, tooth cores at both ends surrounding each pole with a short winding. Is increased by about 1/50 to 1/100 from the average inner radius, the gap Gc is increased, the inner diameters other than both ends are narrowed by about 1/50 to 1/100 than the average inner radius, and the gap Gd is reduced. And the ratio Gd / Gc of Gc to Gd is 1.0
Since the molding is performed so as to be 1 to 1.02, the motor efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration of an iron core of an electric motor according to a first embodiment of the present invention.

FIG. 2 is a plan view showing a configuration of an iron core of the electric motor.

FIG. 3 is a schematic diagram showing a relationship between a tooth core of a core of the electric motor and a rotor core.

FIG. 4 is a plan view showing a configuration of an iron core of the electric motor according to the second embodiment of the present invention.

FIG. 5 is a schematic diagram showing a relationship between a tooth core of a core of the electric motor and a rotor core.

FIG. 6 is a plan view showing a configuration of an iron core of a motor according to a third embodiment of the present invention.

FIG. 7 is a schematic diagram showing a relationship between a tooth core of a core of the electric motor and a rotor core.

FIG. 8 is a plan view of a stator core of a conventional motor.

FIG. 9 is a plan view of a rotor core of the electric motor.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 rotor groove 2 rotor iron core 5 tooth iron core 5A tooth iron core 5B tooth iron core 5C tooth iron core 6 gap 7 tip 7A tip 7B tip 8 stator iron 8A stator iron 8B Stator iron core 9 winding

Claims (3)

[Claims] A rotor core having a plurality of annularly arranged rotor grooves on an outer peripheral side of a rotor has a surface area of a tip end portion of a toothed iron core which is an inner peripheral side of a stator iron core opposed through a gap. Of the magnetic flux generated in one tooth core by the winding that is increased and wound around the tooth core, the magnetic flux in the center reaches the rotor iron core first, and arrives later by the end. The stator core of the induction motor is formed into an arc shape with a smaller radius of curvature than the inner radius of the stator. 2. The stator according to claim 1, wherein a current is applied to a winding wound around the tooth core so that a waveform of a magnetic flux generated in the stator tooth core becomes approximately a part of a sine wave. The tip of the toothed iron core is formed in an arc shape having a radius of curvature smaller than the inner radius, the gap Ga at the leading end in the rotor rotation direction is reduced, and the gap Gb at the lagging end is increased. ,
The stator core of the induction motor according to claim 1, wherein the ratio of Ga to Gb is 1.01 to 1.02. 3. A toothed iron core at both ends of a stator iron core of an induction motor having two teeth having a same pitch and a same tooth width per pole per phase, wherein each pole is surrounded by short windings. Of the inner diameter of about 1/50 to 1/100 of the average inner diameter,
The gap Gc is increased, the inner diameter radius other than both ends is narrowed by about 1/50 to 1/100 from the average inner diameter radius, the gap Gd is reduced, and the ratio Gd / Gc of Gc to Gd is 1.01 to 1.
2. The stator core of an induction motor according to claim 1, wherein stator cores having different air gaps are formed alternately so as to be 02.