JP2002151340A - Laminated iron core and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of obtaining a laminated iron core having superior magnetic properties, without using a heating oven and a laminated iron core. SOLUTION: A laminated iron core is manufactured through a method, which comprises a first step of forming an insulating film that displays an adhesive power, while heat and pressure are applied on an electromagnetic steel plate; a second step of punching unit iron cores out of the electromagnetic steel plate; and a third step of laminating a prescribed number of the unit iron cores and forming them in one piece through application of heat and pressure; the laminated iron core is disposed between two or more electrodes of a high-frequency dielectric heating device; an insulating layer is interposed between the electrode and the laminated iron core; the laminated iron core is pressed; and the insulating films of the unit iron cores are subjected to partial dielectric-heating by the high-frequency dielectric heating device, to form the unit iron cores in a single piece.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an iron core such as a motor and a transformer, and an iron core.

[0002]

2. Description of the Related Art In general, when manufacturing laminated iron cores such as motors and transformers using electromagnetic steel sheets, the electromagnetic steel sheets are unitized by shearing or punching and then laminated.
Further, they are fixed by bolting, caulking, welding or bonding. After the laminated iron core is fixed, the transformer is finally assembled through a winding coil assembling step and the like. It is necessary to strongly fix the laminated iron core because the adhesion of the laminated iron core is weak, and if the lamination is displaced or melted into a unit iron core, the efficiency of coil winding work is reduced.

However, in the case of fixing by bolting, it is necessary to provide a through hole for passing a bolt in the laminated iron core. When a through hole is provided in the laminated iron core, the magnetic characteristics of the laminated iron core are reduced. In the same manner, when the laminated iron core is fixed by welding, the magnetic characteristics of the laminated iron core may be deteriorated due to thermal distortion in the welded portion.

In the case of fixing with an adhesive, a liquid adhesive is poured between the steel plates by utilizing a capillary phenomenon and then fixed. However, it is difficult to flow the adhesive uniformly. In addition, there is a problem that it is difficult to treat the adhesive remaining on the laminated cross section of the iron core.

[0005] Therefore, at present, it is common to fix the laminated iron core by crimping, which can fix the laminated iron core simultaneously with the punching.
However, strong fixing is difficult with caulking, and the laminated iron core may be displaced during assembling of the transformer, or magnetic characteristics may be degraded due to caulking.

On the other hand, an electromagnetic steel sheet provided with a so-called adhesive coating, which is an insulating coating having an adhesive property on the surface of the steel sheet, is punched or sheared and then laminated, and the laminated iron core is fixed by heating and pressing. In this case, there is no deterioration in the magnetic properties observed in welding and the like, and the bonding strength between the steel sheets is large, so that a firmly fixed iron core can be obtained. However, in this case, since it is necessary to pressurize in a heating furnace in order to heat and pressurize, there is a problem that a long time is required for the fixing work and the workability is poor. Further, when a heating furnace is used, even when the temperature outside the iron core reaches the set temperature, temperature unevenness such as a low internal temperature occurs, and it is difficult to heat uniformly.

As a method for improving this, Japanese Patent Application Laid-Open No.
187,626 discloses that, using an electromagnetic steel sheet having an adhesive coating, a high-frequency dielectric heating device that uniformly heats the adhesive coating in a short time without using a heating furnace, by uniformly heating the entire adhesive coating, A method for obtaining a firmly fixed laminated iron core is disclosed.

[0008]

However, the conventional method of uniformly heating the entire adhesive coating has a problem that the magnetic properties of the manufactured iron core deteriorate. Furthermore, especially when the size of the iron core is increased, the heating time is long for heating the entire laminated iron core, and thus further improvement in workability has been desired.

The present inventors have conducted intensive studies on a method of manufacturing an iron core using an electromagnetic steel sheet having such an adhesive coating. As a result, the magnetic characteristics of the manufactured laminated iron core were not deteriorated, The present inventors have found a method of efficiently heating an adhesive coating to obtain a laminated iron core having good magnetic properties, and a laminated iron core obtained by the method, and have reached the present invention.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the gist thereof is as follows. (1) A magnetic steel sheet coated with an insulating film that exerts an adhesive property by heating and pressing on the surface is punched into a unit iron core, and a predetermined number of the obtained unit iron cores are laminated, and then heated and pressed to be integrated. In the method for manufacturing a laminated iron core to be converted, a laminated iron core is disposed between two or more pairs of electrodes of a high-frequency dielectric heating device, and the laminated iron core is subjected to dielectric heating of a part of the unit iron core by the high-frequency dielectric heating device. A method for manufacturing a laminated iron core, wherein the laminated iron core is integrated by applying pressure. (2) The method for manufacturing a laminated iron core according to the above (1), wherein an electrical insulating layer is interposed between the electrode and the laminated iron core. (3) The method for manufacturing a laminated iron core according to (1), wherein the laminated iron core is integrated by dielectrically heating an end of the unit iron core. (4) The method for manufacturing a laminated iron core according to the above (3), wherein the laminated iron core is integrated by performing dielectric heating on a tooth tip of the motor core. (5) In a laminated iron core formed by laminating a predetermined number of unit iron cores made of an electromagnetic steel sheet provided with an insulating coating exhibiting an adhesive ability by heating and pressing the surface, a part of the insulating coating layer of the unit iron core is heated. A laminated iron core, wherein a part of the unit iron core is fixed. (6) The laminated iron core according to the above (5), wherein an end of the unit iron core is fixed. (7) The laminated iron core according to the above (5), wherein a tooth tip is fixed to the motor core.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. As the magnetic steel sheet to be provided to the iron core in the present invention, an insulating steel sheet having an adhesive property on its surface that exerts adhesiveness by heating and pressing, that is, an electromagnetic steel sheet having an adhesive coating is used. The adhesive coating does not necessarily have to be applied to the entire surface 12 on both sides of the steel sheet 11 as shown in FIG. 1 (a), and as shown in FIG.
It is sufficient if the adhesive is applied only to the portion 14 to be heated by bonding. Further, the magnetic steel sheet provided for the iron core in the present invention may be a non-oriented magnetic steel sheet or a directional magnetic steel sheet, and a general steel sheet may be used as the magnetic steel sheet. Furthermore, 0.3
It can be used as a thin electromagnetic steel sheet of 5 mm or less.

Although the structure of the adhesive film is not particularly limited, it must be a dielectric because it is used as an insulating film. Specifically, epoxy resin, phenol resin, acrylic resin, acrylonitrile In general, an organic resin such as urethane is used as a main component.

According to the present invention, after the electromagnetic steel sheet having the above-mentioned adhesive coating is processed into a unitary iron core and laminated, the adhesive coating is heated mainly to develop the adhesiveness of the coating and simultaneously pressed. Thereby, the laminated unit iron cores are firmly fixed. In the present invention, as a method of processing the electromagnetic steel sheet into a unit iron core, for example, a method such as punching, mechanical shearing, laser shearing, or the like can be used. Hereinafter, a method of heating the adhesive coating portion of the laminated iron core in the present invention to develop the adhesive ability of the coating having good magnetic properties will be described.

The present inventors have disclosed in Japanese Patent Application Laid-Open No. H11-187626.
The inventors have intensively studied the method disclosed in Japanese Unexamined Patent Publication (Kokai) Publication. In other words, the present inventors have found that a laminated iron core provided for a core of a motor or the like has a very complicated shape in a tooth portion or the like, and it is difficult to uniformly heat and bond the entire laminated iron core. Therefore, a high-frequency dielectric heating method has been used as a heating means. However, the conventional method can uniformly heat the entire laminated iron core, but the magnetic characteristics of the produced laminated iron core are
There is a problem that the magnetic properties of the material are greatly deteriorated. The reason for this is that, during the cooling process after uniform heating, when the adhesive coating is fixed, internal stress is generated due to the difference in linear expansion coefficient between the adhesive coating and the laminated steel sheet, and particularly, as in the case of the teeth of the motor core. It has been found that a portion having an elongated shape and low rigidity is very susceptible to the above-mentioned internal stress.

On the other hand, the present inventors have invented a method of reducing the area to be bonded and reducing the degree of magnetic deterioration due to bonding. For example, an electrode plate of a high-frequency dielectric heating device is provided at a corresponding position in a part where the internal stress is unlikely to occur or a part where the internal stress is easily released during heating and cooling, and an electric insulating layer is formed between the electrode plate and the laminated iron core. It has been found that by providing such a coating, only the adhesive coating in the laminated iron core is partially heated without deteriorating the magnetic properties.

Hereinafter, this point will be specifically described.
As an example, a 10 μm adhesive coating was applied on both sides.
Punches 35mm thick electromagnetic steel sheet into motor core unit iron core,
An experiment was conducted in a case where 200 sheets were stacked and a laminated iron core having a stacking thickness of 100 mm was sandwiched between electrode plates of a high-frequency dielectric heating device, and a voltage of 3 kV was applied to perform high-frequency dielectric heating.

As shown in FIG. 2, the method of fixing the laminated iron core is as follows: (a) when bonding the entire surface uniformly; (b) when bonding the core back portion at six points; The case where the tooth tip was adhered was compared. At this time, when the iron loss of the iron core material was set to 100, the iron loss of the motor laminated iron core was (b) 103 and (c) 102 with respect to (a) 118. Thus, it can be seen that very good iron loss and magnetic properties were obtained by the fixing methods (b) and (c).
For reference, the number of motor cores by the caulking method in the portion indicated by 25 as in the conventional case (d) was 130. In the conventional motor core formed by caulking, there is almost no adhesive force at the teeth portion, and it is considered that the deterioration rate at the portion is large.

FIGS. 3 (a) and 3 (b) show specific electrode structures of the above (b) and (c). In the figure, 31 is a base electrode of the dielectric heating device, 32 is a core back heating electrode column, and 33 is a tooth tip heating electrode ring. According to the method of the present invention, a very good laminated iron core is obtained by arranging two or more electrodes and arranging two or more electrodes and applying an electric field so as to partially heat the adhesive. Is obtained. In other words, the present inventors
When using a magnetic steel sheet with an adhesive coating and stacking unit iron cores whose characteristics are important like a motor core and performing high-frequency dielectric heating, the area caused by the adhesive heating is reduced to reduce distortion due to the difference in linear expansion coefficient. It has been found that the influence of the deterioration of characteristics due to the above can be suppressed. For example, by arranging an electrode in a tooth portion or a core back portion, it is possible to suppress the above-described adverse effect on characteristics.

The basic structure of the electrode is shown in FIG.
As shown in (1), two or more pairs of electrodes may be formed by arranging two or more electrode columns 32 on one base electrode 31 in a branched manner. Further, as shown in FIG. 3B, a configuration in which the electrode ring 33 is arranged in a branched manner is also conceivable.
Further, as shown in FIG.
5. A type in which the electrode ring 56 is embedded is also an example of the present invention.

Although the laminated iron core and the electrode plate can be in direct contact with each other, there is also a method of disposing an electrical insulating layer between the laminated iron core and the electrode plate as disclosed in Japanese Patent Application Laid-Open No. 11-187626. . In the electrical insulating layer, the effective inter-electrode distance can be ensured, and the applied electric field can be suppressed so that even if the electric field concentrates on the protrusion of the laminated iron core, the value does not exceed the discharge generation limit value. In addition, the electric insulating layer referred to in the present invention does not necessarily need to be a normal electric insulator, and there is no problem with a gas or a liquid as long as it is an electric non-conductor, but the peeling property with the adhesive coating is good. When an electrical insulator is selected, the effect of improving the upper and lower surface appearances of the laminated iron core can be obtained.

Further, a part or the whole of the electric insulating layer may be an electric insulator. Specific electrical insulators include so-called plastic plates or sheets such as Teflon (registered trademark), nylon, polyethylene, and bakelite; rubber sheets such as silicon rubber and chloroprene rubber; plywood such as veneer plates; and paper. it can. Ideally, the thickness of the electrical insulator should be the thickness obtained from the following equation (1) in order to reduce spark (dielectric breakdown) when the power supply voltage is large and the total thickness of the adhesive film is small. It is a target. Thickness of electrical insulator: t [mm]> (V-30) / t1 (1) where V: power supply voltage [kV], t1: total thickness of adhesive coating [mm]

The size of the electrical insulator is not particularly limited. However, if the electrical insulator is too thick, the electric field of the electrical insulator itself is greatly reduced, which is not economical. If the electrical insulator is too thin, it may be broken during handling. A thickness of about 100 microns to several centimeters is good. Furthermore, even if it is a surface-treated steel sheet in which the above-mentioned electric insulator is applied to the surface layer, there is no problem as long as the electric insulating layer is sufficiently secured. The size of the electrical insulator is preferably larger than the laminated iron core to be heated, but is appropriately determined depending on the shape of the laminated iron core, ease of handling, and the like.

Further, if there is a non-uniform gap between the unit iron cores constituting the laminated iron core, the adhesive force decreases non-uniformly inside the laminated iron core during high-frequency dielectric heating. For,
A laminated iron core having good magnetic properties may not be obtained. As a basic process, heating and pressing can be separated,
When pressure is applied simultaneously with heating, high-frequency dielectric heating can be performed with almost no gap between the unit iron cores, and the adhesive force inside the laminated iron core decreases unevenly Without doing so, it is possible to obtain an even adhesive force.

In the present invention, the laminated iron core may be pressurized via the electrode plate and the electric insulator, using the electric insulating layer as the above-mentioned electric insulator. In such a case, high-frequency dielectric heating is performed while the laminated iron core is sandwiched between electric insulators and further sandwiched between electrode plates, and the electrode plates are pressed together with a pressure cylinder or the like. Alternatively, a part or all of the electric insulating layer may be an electric insulator, and the laminated iron core may be pressed through the electric insulator. In such a case, the laminated iron core is sandwiched between electric insulators, and high-frequency dielectric heating is performed by an electrode plate disposed outside the electric insulator while pressing the electric insulator together with a pressure cylinder or the like.

Next, the frequency used by the high-frequency dielectric heating device is 3 MHz to 300 MHz. This is 3MH
If it is less than z, the heating efficiency is inferior, and it takes too long to heat to a temperature at which the adhesive ability is exhibited, and 300 MHz
This is because generation of microwaves cannot be neglected in the case of exceeding, and uniform heating becomes difficult. Also, since the required power is proportional to the area to which the electric field is applied, the spot bonding heating as in the present invention requires less power than the full surface bonding heating, and therefore the power supply capacity can be small, thus reducing the equipment cost. be able to.

Example 1 (FIGS. 3 and 4) A non-oriented electrical steel sheet having a thickness of 0.5 mm and a thickness of 8 μm each having an insulating coating mainly composed of an epoxy resin and having an adhesive property on the surface was prepared. , Punched into the unit iron core shape of the motor core,
Sixty-five motor core materials 42 are laminated to a core back six-point electrode 41 (electrode in FIG. 3A) of a high-frequency dielectric heating device.
FIG. 4 (a) shows a state sandwiched between the upper and lower two sheets, and the core back 6 points + teeth tip electrode 43 (electrode in FIG. 3 (b))
FIG. 4B shows a state where the sheets are sandwiched. When a high-frequency electric field is applied between these electrodes, heat is generated by dielectric heating only in the range of the branched electrode, and only that portion can be adhered.

Example 2 (FIG. 5) A non-oriented electrical steel sheet having a thickness of 0.5 mm is punched into a unit iron core shape of a motor core, and the obtained unit iron core bonded portion 24 shown in FIG. An 8 μm-thick insulating coating mainly composed of an epoxy resin and having an adhesive property was applied to one surface of the substrate. A motor core material 52 obtained by laminating 50 obtained unit iron cores is formed by two upper and lower core back six-point electrodes 51 of a high-frequency dielectric heating device composed of an electrode pillar 55 and an electrode ring 56 embedded in an insulator 54. FIG. 5 shows a state in which the electric insulating layer 53 is disposed between the electrode and the laminated iron core for sandwiching and suppressing dielectric breakdown. When a high-frequency electric field is applied between these electrodes, heat is generated by dielectric heating only in the range of the branched electrode, and only that portion can be adhered.

Embodiment 3 (FIG. 6) FIG. 6 shows an embodiment in which the present invention is incorporated in a punching die. A 0.5 mm thick non-oriented electromagnetic steel sheet slit material 60 having an 8 μm thick insulating coating on one surface with an adhesive property mainly composed of epoxy resin is punched into a unit iron core by a punch 61 and laminated. Motor core stacking fixed area 6
50, and then transferred to the laminated motor core dielectric heating area 63, dielectric heating is performed by the method of the first embodiment, and then transferred to the laminated motor core pressurizing / cooling area 64, and pressure bonding is performed. At the same time, the heated core is cooled, transferred to the laminated motor core payout area 65, and the laminated iron core fixed by the laminated motor core transport belt conveyor 66 is discharged.

[0029]

As described above and as shown in the embodiments, the present invention can efficiently fix a unit iron core in a short time and efficiently without deteriorating the magnetic characteristics, and can provide a laminated iron having good magnetic characteristics. You can get a wick.

[Brief description of the drawings]

FIG. 1 shows a state in which an adhesive coating is applied to a unit iron core,
(A) is an example of the entire application of the adhesive coating, and (b) is an example of the partial application of the adhesive coating.

2A and 2B show a state in which an adhesive coating is applied to a motor core, wherein FIG. 2A is an example of full-surface adhesion, FIG. 2B is an example of partial adhesion (core back 6-point adhesion), and FIG. 6
An example of point + tooth tip bonding 1), and (d) is an example of caulking the motor core.

FIG. 3 (a) shows an electrode example of partial adhesion (six core back bonding) on a motor core, and (b) an electrode example of partial adhesion (six core back + teeth tip adhesion) on a motor core.

FIG. 4 (a) is an example of an arrangement of electrodes and laminated iron cores of partial adhesion (six core back bonding) in a motor core, and FIG. 4 (b) is a partial adhesion (six core back + teeth tip bonding) of a motor core. An example of the arrangement of electrodes and laminated iron cores is shown.

FIG. 5A is a development view showing an arrangement relationship between electrodes, electrical insulators, and a laminated iron core of a partial adhesion (six core backs + teeth tip adhesion) in a motor core, and FIG. It is a figure which shows the setting condition of the electrode of adhesion | attachment (6 core backs + tooth tip adhesion | attachment), an electrical insulator, and a laminated iron core.

FIG. 6 is an explanatory view showing an embodiment in which the present invention is incorporated in a punching die.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 Full-surface adhesive coating material 12 Full-surface adhesive coating application part 13 Partial adhesive coating application material 14 Partial adhesive coating application part 21 Motor core 22 Core back 23 Teeth 24 Adhesion part 25 Caulking part 31 Dielectric heating device base electrode 32 Motor core core back Electrode pillar for 6-point heating adhesion 33 Electrode ring for heating tip of motor core 41 Electrode for heating 6 core heating core core 42 Motor core 43 6 heating core core back + heating tip Electrodes for the core 51 Motor core core back 6 points + Teeth tip heating bonding electrode (with electric insulating jig) 52 Motor core 53 Electric insulating layer 54 Electric insulator 55 Motor core core back 6 points Heat bonding electrode post 56 Electrode ring for heating and bonding the tip of the teeth of the motor core 0 electromagnetic steel slit member 61 punched 62 laminated motor core stacking fixed area 63 laminated motor core dielectric heating area 64 laminated motor core pressing and cooling area 65 laminated motor core dispensing area 66 laminated motor core conveyor belt conveyors

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Ikuyo Nomura 1 Fujimachi, Hirohata-ku, Himeji-shi F-term in Nippon Steel Corporation Hirohata Works (reference) 5E062 AA01 AC05 AC13 AC15

Claims (7)

[Claims] 1. An electromagnetic steel sheet provided with an insulating coating exhibiting an adhesive ability by applying heat and pressure to a surface thereof is punched into a unit iron core, and a predetermined number of the obtained unit iron cores are laminated and then heated and pressed. In the method for manufacturing a laminated iron core to be integrated, a laminated iron core is arranged between two or more pairs of electrodes of a high-frequency dielectric heating device, and a part of the unit iron core is dielectrically heated by a high-frequency dielectric heating device and pressed. A method for manufacturing a laminated iron core, comprising: 2. The method for manufacturing a laminated iron core according to claim 1, wherein an electric insulating layer is interposed between the electrode and the laminated iron core. 3. The method for manufacturing a laminated iron core according to claim 1, wherein the laminated iron core is integrated by dielectrically heating the end of the unit iron core. 4. The method for manufacturing a laminated iron core according to claim 3, wherein the laminated iron core is integrated by dielectrically heating the tip end of the teeth in the motor core. 5. A laminated iron core in which a predetermined number of unitary iron cores each made of an electromagnetic steel sheet coated with an insulating coating exhibiting an adhesive ability by heating and pressurizing by high-frequency dielectric heating are laminated on the surface. A laminated iron core, wherein a part of an insulating coating layer of the core is heated and a part of a unit iron core is fixed. 6. The laminated iron core according to claim 5, wherein an end of the unit iron core is fixed. 7. The laminated iron core according to claim 5, wherein a tooth tip portion is fixed to the motor core.