JP2000295825A - Cage rotor and method of manufacturing the same - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a stable, high-efficiency cage rotor with low loss at low cost. SOLUTION: After a pretreatment step of degreasing a rotor core 1 in which silicon steel sheets provided with a plurality of slot portions 2 are laminated, a first insulating film 3 covering the surface of the rotor core 1 is formed,
After forming the first insulating film 3, a second insulating film 4 covering the inner peripheral surface of the slot portion 2 is formed. After forming the second insulating film 4, a third insulating film 5 covering the inner peripheral surface of the slot portion 2 is formed. Forming a third insulating film 5, and forming a conductor bar by connecting an inner peripheral portion of the slot of the rotor core and both end surfaces of the core with aluminum to form a conductor bar.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cage rotor, and more particularly to an improvement in stray load loss.

[0002]

2. Description of the Related Art In recent years, there has been a strong demand for higher efficiency and energy saving in cage type induction motors widely used in various industrial equipments from an environmental point of view, and there is an urgent need to improve various losses.

[0003] Conventionally, the rotor of a cage induction motor made of aluminum die-casting has no insulation between the conductor and the iron core, causing eddy current loss and stray load loss of the rotor, thereby reducing the efficiency of the motor. As a countermeasure against this problem, a method of forming an insulating film on the rotor core with an oxide film or a method of obtaining an insulating film between the conductor bar and the iron core with a heat-resistant paint have been proposed as countermeasures.

The present applicant has also proposed a method of forming an insulating film on a rotor core using a zinc phosphate film and one kind of heat-resistant paint.

[0005]

However, in the method of treating the zinc phosphate film and the heat-resistant paint applied previously, the adhesion of the heat-resistant paint to the slot surface is not sufficient, and the insulating film is damaged at the time of aluminum die casting. Stable insulation performance could not be obtained.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a stable, high-efficiency squirrel-cage rotor with low loss at low cost.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a pre-treatment step of degreasing a rotor core laminated with a plurality of silicon steel sheets provided with a plurality of slots, and a pre-treatment step. After the first insulating film forming step of covering the rotor core surface later, after forming the first insulating film, after forming a second insulating film to improve the adhesion of a third insulating film described below, after the formation of the slot inner peripheral surface A cage-type rotor comprising: a third insulating film forming step to cover; and a die-casting step of forming a conductor bar by connecting the inner peripheral portion of the slot of the rotor core and both end faces of the core with aluminum after the third insulating film forming step. It is.

[0008] Accordingly, the stray load loss of the cage rotor can be reduced, so that the efficiency of the cage induction motor can be improved and stable efficiency can be obtained.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to solve the above-mentioned problems, the present invention provides a rotor core comprising a plurality of laminated silicon steel sheets provided with a plurality of slots, and a first insulating member provided on the surface of the rotor core. A coating, a second and a third insulating coating provided on an inner periphery of the rotor core slot portion, and a conductor bar having an inner peripheral portion of the rotor core connected to both end surfaces of the core with aluminum, The cage rotor is characterized in that the first insulating film is zinc phosphate and the second and third insulating films are heat-resistant paint.

A pretreatment step of degreasing a rotor core laminated with silicon steel sheets provided with a plurality of slots,
A first insulating film forming step of covering the rotor core surface after the pretreatment step, a second insulating film forming step of covering the slot inner peripheral surface after the first insulating film is formed, and after the second insulating film is formed. A third insulating film forming step of covering the inner surface of the slot, and a die casting step of connecting the inner surface of the slot of the rotor core and both end surfaces of the core with aluminum after the third insulating film forming step to form a conductor bar. And a method of manufacturing a cage rotor.

Further, a heat-resistant coating material containing 55 to 65% by weight of an inorganic pigment as a main component is used for the first insulating film and the second insulating film using a weak alkaline powder degreasing agent for the degreasing treatment. Special silica compound 10 for the third insulating film
3. The method for manufacturing a cage rotor according to claim 2, wherein a heat-resistant paint mainly containing -15% by weight and 25-30% by weight of an inorganic pigment is used as a main component.

As described above, since a good insulating film can be obtained between the cage rotor core and the conductor bar, stray load loss of the induction motor using the cage rotor can be reduced.

Further, after the degreasing treatment and the first insulating film are formed on the entire rotor core, an insulating film is further formed on the inner peripheral portion of the slot with second and third heat-resistant paints to withstand the high temperature of aluminum die casting. An insulating film can be obtained.

Further, after degreasing with a weakly alkaline powder,
By using a heat-resistant paint that is familiar with the first insulating film and the third insulating film as the second insulating film, an insulating film having good adhesion and heat resistance can be obtained.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, the rotor core 1 is formed by laminating silicon steel sheets having a plurality of slots 2 disposed on the outer periphery thereof, and then degreasing the entire rotor core 1 with a weak alkaline powder degreasing agent. . Next, a first insulating film 3 is formed on the surface of the degreased rotor core 1 with zinc phosphate. Next, a portion other than the slot portion 2 of the rotor core 1 on which the first insulating film 3 is formed is masked and covered, and the second insulating film 4 is formed only on the slot portion 2.

The first insulating film 3 improves the adhesion of the rotor core 1 to the second insulating film 4, especially on the fractured surface.

The second insulating film 4 is made of an inorganic pigment 5
Kneading a synthetic resin paint containing 5 to 65% by weight as a main component,
It is obtained by applying or dipping using a heat-resistant paint diluted with an alcohol-based mixed solvent and then naturally drying for about 15 minutes to volatilize the solvent.

The second insulating film 4 contains an inorganic pigment and has an appropriate thickness and surface roughness, and has adhesion to both the first insulating film 3 and the third insulating film 5. It is thought that it can be improved.

The third insulating film 5 is composed of 10 to 15% by weight of a special silica compound and 25 to 30% by weight of an inorganic pigment.
After kneading a synthetic resin paint containing as the main component, apply or dipped using a heat-resistant paint diluted with an alcohol-based mixed solvent,
Air-dry to evaporate the solvent, and then 160 ° C2
It is obtained by curing in 0 minutes.

As a result, an insulating film as thin as about 20 μm as a whole and hard to peel off can be obtained.

Thereafter, in the same manner as in a normal aluminum die casting process, a rotor core provided with the third insulating film 5 is set on a die casting machine, and molten aluminum at a temperature of 720 ° C. is cast to form a conductor bar 6. A cage rotor is obtained.

The cage rotor thus obtained is
Having good three insulating layers between the conductor bar 6 and the rotor core 1, when incorporated in a squirrel-cage induction motor,
The stray load loss of the rotor can be reduced, the efficiency of the electric motor can be improved, and stable efficiency can be obtained.

In the experiment, a method of obtaining an insulating film with a zinc phosphate film and one kind of heat-resistant paint using a 1.5 kW cage-type induction motor and a cage rotor of the present invention were incorporated. As a result of a characteristic test, the variance of the efficiency of the motor incorporating the cage rotor of the present invention can be reduced from 1% to 0.5% as compared with that of the prior application.

[0025]

As is apparent from the above embodiment, according to the present invention, a cage rotor having a stable insulating layer which is thin and hard to peel off between the conductor bar and the rotor core can be obtained.

By using the cage rotor, stray load loss can be reduced as compared with the conventional cage induction motor.
Efficiency can be improved and stable efficiency can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a cage rotor according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a rotor core according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotor core 2 Slot part 3 First insulating film 4 Second insulating film 5 Third insulating film 6 Conductor bar

Claims (3)

[Claims] 1. A rotor core in which silicon steel sheets provided with a plurality of slots are laminated, a first insulating film provided on a surface of the rotor core, and an inner periphery of the rotor core slot. Second and third insulating films, and a conductor bar in which the inner peripheral portion of the slot of the rotor iron core and both end surfaces of the iron core are connected by aluminum, wherein the first insulating film is zinc phosphate, A cage rotor, wherein the third insulating film is a heat-resistant paint. 2. A pretreatment step of degreasing a rotor core laminated with silicon steel sheets provided with a plurality of slot portions, a first insulating film forming step of covering the rotor core surface after the pretreatment step, A second insulating film forming step of covering the inner peripheral surface of the slot after forming the first insulating film, a third insulating film forming step of covering the inner peripheral surface of the slot after forming the second insulating film, A die-casting step of forming a conductor bar by connecting the inner peripheral portion of the slot of the rotor core and both end faces of the core with aluminum after the step of forming the insulating film. 3. A degreasing treatment using a weakly alkaline powder degreasing agent, a first insulating film as a zinc phosphate film, a second insulating film as a heat-resistant paint containing 55 to 65% by weight of an inorganic pigment as a main component, 3. The method for manufacturing a cage rotor according to claim 2, wherein a heat-resistant paint containing 10 to 15% by weight of a special silica compound and 25 to 30% by weight of an inorganic pigment as main components is used for the insulating film.