JP2006129640A - Method of manufacturing iron core for electrical appliance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an iron core for an electric appliance for which sticking removal is performed sufficiently and uniformly and that is excellent in iron loss property. <P>SOLUTION: In the method of manufacturing the iron core, which is made of a magnetic steel sheet that is manufactured through the processes of blanking, stacking, forming, and stress-relief annealing, for an electric appliance, the manufacturing method of this invention has a process of impressing ultrasonic waves after the stress-relief annealing process. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method of manufacturing an iron core for electric equipment such as a motor and a transformer used for various industrial uses and consumer uses.

  Conventionally, iron cores of electrical equipment, for example, motors, have a 0.35mm or 0.50mm thickness of thin electromagnetic steel sheet punched into a stator shape or rotor shape using a mold, and then the necessary thickness of the punched electromagnetic steel sheet Manufactured by laminating only. At this time, in order to mold and fix the laminated material as an iron core, caulking, welding, screwing, and the like are often used as this method.

  However, in the iron core manufacturing process, in the punching process, plastic strain and elastic strain due to breakage may remain at the end of the core material, and elastic strain may remain in the entire core. In the caulking step, the laminated material is fixed by locally generating round or V-shaped plastic deformation in the laminating direction, so that plastic strain and elastic strain remain around the caulking. To do. In welding, thermal residual stress is generated at the penetration portion and the periphery thereof, and also in screw fastening, processing distortion due to punching around the screw hole and residual stress when tightened with a screw are generated. Therefore, for the purpose of removing these residual strains, annealing (hereinafter referred to as strain relief annealing) in which annealing is performed after heating to a temperature around 750 ° C. has been conventionally performed.

  However, in the above strain relief annealing, although the strain can be removed, a phenomenon called so-called sticking, in which the laminated steel sheets are somewhat destroyed and burned up in the part where the temperature distribution has occurred, particularly in the high temperature part, is broken. Will happen. Due to this sticking, the iron loss of the laminated iron core is significantly deteriorated compared to the iron loss of the material.

On the other hand, as a method for removing the sticking state, for example, Patent Document 1 describes a technique of applying an impact force such as hammering or dropping from the outside. Patent Document 2 describes a method of sandwiching a rubber sheet between layers from the viewpoint of preventing a short circuit between layers.
JP 50-90901 A JP-A-5-231654

  However, in the method described in Patent Document 1, the effect of removing sticking is not uniform, and the effect of improving iron loss by strain relief annealing is not sufficiently reflected. Furthermore, distortion may be applied by the impact force and the iron loss may deteriorate.

  In Patent Document 2, the space factor decreases, and it is difficult to coexist with strain relief annealing for strain relief.

  The present invention has been made in view of the above points, and provides a method for manufacturing an iron core for electrical equipment that is sufficiently and uniformly removed from sticking and that has excellent iron loss characteristics.

  As a result of studying to solve the above-described problems of the prior art, the present inventors are effective in obtaining an iron core for electrical equipment having excellent iron loss characteristics by performing a process of applying ultrasonic waves after the annealing process. It turns out that there is.

  The present invention has been made based on such findings, and the gist thereof is as follows.

  In the manufacturing method of an iron core for an electric device made of an electromagnetic steel sheet manufactured through the steps of punching, lamination, molding, and strain relief annealing, the method includes the step of applying an ultrasonic wave after the annealing step. It is a manufacturing method of an iron core.

  ADVANTAGE OF THE INVENTION According to this invention, the iron core for electrical devices excellent in the iron loss characteristic can be obtained. In the present invention, sticking is sufficiently and uniformly removed by applying ultrasonic waves after the strain relief annealing process. Therefore, it is possible to apply strain relief annealing and the space factor does not decrease.

  Further, since the iron loss improvement effect by the strain relief annealing is not impaired by the sticking removal, a highly efficient motor can be stably manufactured. Furthermore, compared with the conventional sticking removal method, the application of ultrasonic waves is excellent in terms of reducing man-hours because an effective effect can be obtained by a short time treatment in the production line.

  From the above, the iron core for electric equipment of the present invention is very useful as a material for iron cores such as electric equipment, transformers, reactors and the like.

  Below, the manufacturing method of the iron core for electrical devices of this invention is demonstrated in detail.

  In the present invention, an electromagnetic steel sheet is used. First, the electromagnetic steel sheet is punched into a predetermined shape to obtain a bulk core. At this time, from the viewpoint of productivity, it is desirable to continuously punch a steel plate or a hoop-like electromagnetic steel plate using a press machine.

  Next, a plurality of bulk cores are laminated to form a laminated material. At this time, for example, it can be temporarily restrained or temporarily fixed with a simple pressing jig or the like so that individual punched steel plates do not fall apart.

  Next, the laminated material is molded and fixed. For example, the laminated material is fixed by caulking. At this time, after being restrained by a molding jig, it is possible to fix it by caulking. Further, as a method other than caulking, a method of welding and screwing can be used for fixing the laminated body.

  Next, a strain relief annealing process is performed on the fixed laminated material. For example, an electric furnace or an induction heating furnace can be used for the strain relief annealing. The strain relief annealing treatment at this time is usually preferably performed at about 750 to 850 ° C. for 30 minutes or more.

  Next, after annealing, an ultrasonic wave is applied. This is the most important requirement in the present invention. By including this step, sticking is sufficiently and uniformly removed in the present invention, and an iron core for electrical equipment having excellent iron loss characteristics can be obtained. Hereinafter, the ultrasonic wave application process will be described in detail.

  Prepare 15 motor stator cores (50A350 material applied) after strain relief annealing, 5 remove sticking by the conventional hammering method, and the remaining 10 are immersed in a medium mixed with anti-rust oil. 5 ultrasonic waves were applied for 30 seconds at 50 kHz or 100 kHz, respectively. Next, the core was wound, and the iron loss was measured by a method based on JIS (C 2550). The obtained results are shown in FIG.

  As shown in FIG. 1, by removing the sticking after punching, laminating, caulking, and strain relief annealing of the iron core for electrical equipment, the ultrasonic method that can be applied to the entire core is changed from the conventional method using local impact force. It can be seen that the iron loss improvement effect by the annealing can be fully enjoyed.

  In the present invention, when applying ultrasonic waves, for example, the frequency is preferably 20 kHz to 1 MHz for general reasons. The application time is preferably 30 to 60 seconds for productivity reasons. However, the conditions are not limited to this, and can be appropriately set and adjusted in consideration of the sticking state.

  As a method for applying ultrasonic waves, the simplest method is to put the entire core in a medium in which ultrasonic waves are easy to conduct and apply ultrasonic vibration from the outside. At this time, water is generally used as the ultrasonic conduction medium, but it is also advantageous to use an aqueous medium mixed with a rust preventive agent from the viewpoint of rust formation of the steel sheet. Furthermore, the method of applying ultrasonic waves is not limited to the above, and it is also possible to apply ultrasonic vibration directly to the core by contacting a contactor such as a contact plate that vibrates ultrasonically to the motor core, other than the method using a medium It is.

  In the present invention, the composition of the electrical steel sheet is not particularly limited. For example, steel plates specified by JIS C 2552, steel plates specified by JIS C 2553, and steel plates specified by JIS C 2555 can be targeted. Here, when the characteristics after core forming such as motor core iron loss are taken into consideration, it is preferable to use a non-oriented electrical steel sheet having a Si content of 2 mass% or more from the viewpoint of increasing the efficiency of the motor. There is no special limitation on the plate thickness, but from the viewpoint of increasing the efficiency of the motor, an electromagnetic steel plate having a thickness of 0.35 mm or less is particularly suitable. In the present invention, such a thin steel plate can be used without any problem. it can.

  Using 35A230 material, punching, stacking, and caulking were sequentially performed, followed by strain relief annealing at 750 ° C. for 1 hour to produce 10 stator cores having an outer diameter of 300 mmφ. About five of them, as a comparative example, a uniform impact force was carefully applied with a plastic hammer. On the other hand, as an example of the present invention, for the remaining five, a contact plate curved along the side surface was prepared on the side surface of the laminate, thereby applying a 25 kHz ultrasonic wave to the entire core. Then, iron loss was measured for each stator core by a method in accordance with JIS 2550. The obtained results are shown in FIG.

  FIG. 2 shows that in the example of the present invention, the iron loss after the stress relief annealing is low, and the magnetism is good and stable even after removal of the sticking. On the other hand, in the comparative example, the variation of the iron loss value is large, and stable and good magnetism is not obtained.

  It is very useful as a material for iron cores, transformers, reactors, etc. for electrical equipment.

It is a figure which shows the relationship with the iron loss value by the difference in the sticking removal method. It is a figure which shows the relationship with the iron loss value by the difference in the sticking removal method. (Example 1)

Claims (1)

In the manufacturing method of the iron core for electrical equipment consisting of the electromagnetic steel sheet manufactured through the processes of punching, lamination, molding, strain relief annealing,
The manufacturing method of the iron core for electrical devices characterized by having the process of applying an ultrasonic wave after the said distortion removal annealing process.

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