JP2021089965A5 - - Google Patents

Description

A manufacturing method for manufacturing an iron core in which electromagnetic steel sheets are bonded to each other through bonding of fine particles made of magnesium oxide or aluminum oxide deposited in the gaps between the laminated electromagnetic steel sheets.

The present invention relates to a method for manufacturing an iron core used in an electric device such as an electric motor or a transformer, and the electromagnetic steel sheets are joined together with fine particles made of magnesium oxide or aluminum oxide deposited in the gaps between the laminated electromagnetic steel sheets. It is a manufacturing method for manufacturing an iron core in which the steel cores are bonded. Since magnesium oxide or aluminum oxide has higher heat resistance, hardness, and compression strength than electromagnetic steel plates, the electromagnetic steel plates are bonded to each other through the bonding of fine particles made of magnesium oxide or aluminum oxide. Can be done. In addition, the electromagnetic steel sheet is an iron plate with improved magnetic properties by adding silicon to iron in order to control the alignment of crystal orientation and the width of the magnetic zone, and it was called a silicon steel sheet because it contains silicon. Since there are electromagnetic steel sheets that do not contain silicon, they are now called electromagnetic steel sheets.

For iron cores used in electrical equipment such as motors and transformers, electromagnetic steel sheets with an insulating coating are laminated, and the electrical steel sheets are fixed to each other by welding or caulking, or adhesive is applied to the electrical steel sheets with an insulating coating. Then, the electromagnetic steel sheets are bonded to each other, and finally, the laminated electromagnetic steel sheets are cut into the shape of an iron core, and a large number of iron cores are manufactured from the laminated electromagnetic steel sheets. Since a large number of cores are continuously manufactured from laminated electromagnetic steel sheets, the manufactured cores are inexpensive.
That is, since the electromagnetic steel sheet is manufactured in the rolling process, the flatness of the surface is remarkably superior to the flatness of the surface of the soft magnetic powder represented by the iron powder manufactured by the atomizing method. Therefore, the bonding force based on the anchor effect between the insulating film formed on the electrical steel sheet and the electrical steel sheet is extremely small. Therefore, the insulating film is easily peeled off from the surface of the electrical steel sheet due to the impact when punching the laminated electrical steel sheet. Therefore, a process for fixing the laminated electromagnetic steel sheets is required. Therefore, it is different from the manufacturing method in which a collection of insulated soft magnetic powder is filled in a mold and further compressed to produce a dust core in the mold.
On the other hand, if the iron loss of the manufactured iron core is within the allowable range, the iron core is incorporated into the electric equipment and used. If the magnitude of the iron loss is unacceptable, the core is magnetically annealed to reduce the hysteresis loss of the core. The energy loss generated when the iron core is electromagnetically converted consists of an eddy current loss and a hysteresis loss, and both are collectively referred to as an iron loss. This iron loss causes the iron core to generate heat. In order to reduce the iron loss, the insulating property of the electromagnetic steel sheets is improved, and the eddy current flowing through the gaps between the electromagnetic steel sheets is reduced. Alternatively, the iron core is magnetically annealed to eliminate the machining strain of the electrical steel sheet, restore the holding force of the electrical steel sheet, and reduce the hysteresis loss. The annealing process may be referred to as strain-removing annealing that removes the machining strain of the electrical steel sheet, but in the present invention, it is expressed as magnetic annealing that restores the holding force of the electrical steel sheet.

On the other hand, the conventional method for manufacturing an iron core causes various problems when fixing the laminated electromagnetic steel sheets. For example, when the end portions of the laminated electromagnetic steel sheets are fixed by welding, thermal strain occurs in the electromagnetic steel sheets during welding, and the hysteresis loss of the electromagnetic steel sheets increases. In addition, substances vaporized from the insulating layer during welding or scattered substances attack the insulating layer and form pinholes in the insulating layer. Further, when the magnetic steel sheets laminated by caulking are fixed, distortion occurs due to the load applied at the time of caulking, and the hysteresis loss of the electrical steel sheets increases. Further, when the area of the laminated electromagnetic steel sheets is large, the caulking strength varies, and a portion where the fixing strength is insufficient is generated. Alternatively, if the thickness of the electrical steel sheet is thin, sufficient caulking strength cannot be obtained. Further, when the electromagnetic steel sheets are bonded to each other by an adhesive, the workability of applying the adhesive to the electromagnetic steel sheets having an insulating film and laminating the electromagnetic steel sheets one by one is poor. Further, when the area of the magnetic steel sheet is large, the thickness of the adhesive varies, and a portion where the adhesive strength is insufficient is generated. Further, the heat resistance of the adhesive is low, and the adhesive is thermally decomposed by magnetic annealing of the iron core, and the insulating property of the gap between the electromagnetic steel sheets is lowered. As described above, various problems occur when the laminated electromagnetic steel sheets are fixed.
That is, since the surface of the electrical steel sheet is flat, the bonding force based on the anchor effect between the insulating film formed on the electrical steel sheet and the electrical steel sheet is extremely small. Therefore, when the laminated electromagnetic steel sheets are punched out, an impact is applied to the insulating coating, and the insulating coating is easily peeled off or dropped from the gaps between the electromagnetic steel sheets, and the insulation between the gaps between the electromagnetic steel sheets is lost. Therefore, in the conventional method for manufacturing an iron core, a process of fixing the laminated electromagnetic steel sheets is indispensable. Therefore, the problem that occurs when the laminated electromagnetic steel sheets are fixed cannot be solved unless the fixing method is changed. However, the means for easily fixing the electromagnetic steel sheets made of metal to each other are limited to the above-mentioned three means. Therefore, if a new method for manufacturing an iron core, which eliminates the need for the process of fixing the laminated electromagnetic steel sheets, can be found, this problem can be fundamentally solved.

Further, in the conventional method for manufacturing an iron core, thermal strain is generated at the time of welding, machining strain is generated at the caulked portion at the time of caulking, and further, machining strain is generated at the time of punching the electromagnetic steel sheet. Due to such various strains, the holding force of the electrical steel sheet is increased, and the hysteresis loss of the iron core is increased. Therefore, the iron core is incorporated into the electrical equipment after magnetic annealing to reduce hysteresis loss. On the other hand, magnetic annealing is performed at a temperature of 750-820 ° C. in a reducing atmosphere in which the electrical steel sheet is not oxidized. Therefore, conventionally, a chromium compound having high heat resistance has been used for the insulating film of the electrical steel sheet. However, the RoHS Directive (Hazardous Substance Restriction Directive) for electrical products for Europe and the Domestic Green Purchasing Law (Act on Promotion of Procurement of Environmental Goods by the Government) restrict the use of heavy metals, which are environmentally hazardous substances. There is a need for an insulating coating that does not contain chromium compounds.

Various proposals have been made to solve various problems and problems related to such an insulating layer.
For example, in Patent Document 1, a surface treatment agent containing a silane compound, a silane coupling agent, and silica particles is used, and an insulating film is formed on a surface having a surface roughness curve with a skewness Rsk of 1 or less. A technique has been proposed in which a chrome-free insulating film having excellent insulation, tension pad resistance, and punching property is formed by forming the insulating film. Here, the skewness Rsk represents the symmetry between the peaks and valleys when the average line between the peaks and valleys of the surface roughness is centered, and if Rsk is positive, it is below the average line. Since it means that the surface roughness curve is biased to the side, the volume of the valley part is larger than that of the mountain part in the surface roughness. Further, the tension pad resistance is a felt-shaped tension pad, and represents the difficulty of peeling of the insulating film when rubbing the surface of the electromagnetic steel sheet with an insulating film.
However, the coefficient of thermal expansion of this insulating coating is nearly an order of magnitude smaller than the coefficient of thermal expansion of the magnetic steel sheet. Therefore, due to a sudden temperature change such as magnetic annealing, the stripped film is peeled from the electromagnetic steel sheet, and the peeled insulating film does not have corrosion resistance and oil resistance. On the other hand, when manufacturing an iron core, the electromagnetic steel sheets having the main insulating film formed are laminated, the laminated electromagnetic steel sheets are fixed, and then the laminated electromagnetic steel sheets are punched out. Since the electrical steel sheet is subjected to machining strain, magnetic annealing is required, and the above-mentioned problems occur during magnetic annealing.

Further, in Patent Document 2, an insulating layer made of a phosphoric acid compound is formed by using nitric acid and metal nitrate, which are strongly acidic and have strong etching properties, and a metal phosphate and a chelating agent, and whitening and storage immediately after production. A technique for forming a chrome-free insulating film in which whitening during time and deterioration of adhesion after brewing treatment are suppressed has been proposed. Here, whitening means that when an electromagnetic steel sheet is etched with an acidic etching solution, iron in the electromagnetic steel sheet elutes and reacts with a phosphate in a treatment liquid that forms an insulating film to form iron phosphate. Alternatively, it means that when the electrical steel sheet is stored in a hot and humid environment for a long period of time, hydroxide is formed on the surface of the electrical steel sheet due to dew condensation, which discolors the electrical steel sheet. In addition, when processing a cut or punched electrical steel sheet into a motor or transformer, the steel sheet is oxidized to the extent that the surface exhibits an interference color in order to suppress short-circuiting of the end face and improve the rust prevention of the cut or punched end face. Is also called brewing process). When such a bluing treatment is performed, the adhesion of the insulating film deteriorates.
However, the properties required for the electrical steel sheet on which the insulating film is formed are not limited to whitening prevention and adhesion of the insulating film. For example, it has punching property. Since sufficient punching property cannot be obtained by this technology alone, there is a description that an aqueous synthetic resin is added. However, the water-based synthetic resin does not have heat resistance in magnetic annealing. Therefore, punching property and magnetic annealing are not compatible with each other. In addition, there is an insulating property of the insulating film. Since sufficient insulation resistance cannot be obtained by this technology alone, there is a description that colloidal silica is added. However, since the coefficient of thermal expansion of colloidal silica is nearly an order of magnitude smaller than the coefficient of thermal expansion of electrical steel sheets, the insulating film is peeled off by a sudden temperature change such as magnetic annealing. Further, since a strongly acidic etching solution is used, sufficient cleaning is required after the formation of the insulating film, and the waste liquid treatment is costly due to the environmental aspect. This increases the production cost.

On the other hand, the insulating layer is required to have various properties described below not only for insulating resistance but also for manufacturing an iron core and for long-term use of an electric device incorporating an iron core.
The first property is related to the continuous punching property of the laminated magnetic steel sheets. In other words, if an insulating material made of an inorganic material is used to improve the heat resistance of the insulating material, the hardness of the inorganic material is high when the laminated electromagnetic steel sheet on which the insulating film is formed is continuously punched by a press machine. , The wear of the cutter blade progresses. Therefore, it is desirable that the cutter blade is not attacked, the heat resistance is high, and the insulating property is high. The second property is related to the weldability of the laminated electrical steel sheets. That is, when welding the end faces of the laminated electrical steel sheets, it is easy to weld, and the substance vaporized from the insulating layer or the scattered substance attacks the insulating layer and insulates the pinhole. It is necessary not to form a layer. The third property is that when the electrical steel sheets are laminated or punched, the insulating layer needs to have an adhesion strength that does not fall off or peel off from the flat surface of the electrical steel sheets. The fourth property requires heat resistance to withstand magnetic annealing. The fifth property is that it is necessary to prevent seizure between electrical steel sheets called sticking during magnetic annealing. The sixth property is that heat resistance is required so that the insulating layer does not crack and the insulating layer does not peel off even with a sudden temperature change such as magnetic annealing. The seventh property is that when the iron core is immersed in hot water or salt water, it needs to have corrosion resistance to withstand hot water or salt water. The eighth property is that when the iron core is immersed in high-temperature insulating oil for a long time, it is necessary that the insulation resistance and the adhesion strength between the electromagnetic steel sheets do not change even if they are immersed in high-temperature insulating oil for a long time. Become.
However, the above eight properties are incompatible with conventional insulating materials. For example, many of the insulators made of inorganic materials have high heat resistance and high hardness, so that they satisfy the fourth and sixth properties, but not the first property. Further, if the adhesion strength between the insulating layer and the electrical steel sheet is high, the third property is satisfied, but since the fourth to eighth properties are different from the adhesion strength, the fourth to eighth properties are not always satisfied. No. Therefore, it is difficult to realize an insulating layer satisfying all eight properties.
By the way, all of the above eight properties are not caused by the material of the insulating layer. That is, since the first property is a problem that occurs when the laminated electromagnetic steel sheets are punched out, the first property becomes unnecessary unless the laminated electromagnetic steel sheets are punched out. Further, since the second property is a problem that occurs when the laminated electromagnetic steel sheets are fixed by welding, the second property becomes unnecessary unless the laminated electromagnetic steel sheets are welded. Further, since the third property is a problem that occurs when the laminated electromagnetic steel sheets are laminated or punched out, the third property becomes unnecessary unless the laminated electromagnetic steel sheets are punched out.
Therefore, in order to realize all eight properties required for the insulating layer, the iron core is manufactured by a new manufacturing method that does not require the first to third properties, and new materials and new materials are used. There is no choice but to find a way to form an insulating layer that satisfies the fourth to eighth properties depending on the material structure. Further, the problem that occurs when the laminated electromagnetic steel sheets are fixed as described in paragraph 3 can be solved by finding a new method for manufacturing an iron core that does not require the process of fixing the laminated electromagnetic steel sheets. As described above, there is a demand for a manufacturing method for manufacturing an iron core by a new manufacturing method.

Japanese Unexamined Patent Publication No. 2015-10242 Japanese Unexamined Patent Publication No. 2013-249486

As explained in paragraph 3, various problems occur when fixing laminated electromagnetic steel sheets, and the problem cannot be solved unless a new method for manufacturing an iron core is found, which eliminates the need for the process of fixing the laminated electromagnetic steel sheets. .. Further, the eight properties required for the insulating layer described in paragraph 7 eliminate the need for the first to third properties, that is, the process of fixing the laminated electromagnetic steel sheets, which is a new manufacturing method. It can be solved by finding out. Further, the fourth to eighth properties can be realized by finding a method for forming an insulating layer composed of a new material and a new material structure.
Therefore, the problems to be solved by the present invention are, firstly, to find a new method for manufacturing an iron core that eliminates the need for a process of fixing laminated electromagnetic steel plates, and secondly, to use a new material and a new material structure. , Found a method for forming an insulating layer satisfying the properties of the fourth to eighth, and thirdly, the above two methods use an inexpensive raw material and consist of an extremely simple treatment, and an iron core based on a conventional manufacturing method. Similarly, it is to find a manufacturing method of an iron core, which is a manufacturing method for manufacturing an inexpensive iron core.

A plurality of electromagnetic steel plates cut in the shape of the core, are laminated through the collection of fine particles of magnesium oxide or aluminum oxide, compressing the electromagnetic steel sheets the stacking, said fine particles of said magnesium oxide or the aluminum oxide It is composed of bonding to the surface of an electromagnetic steel plate, bonding fine particles made of magnesium oxide or aluminum oxide to each other, and bonding the electromagnetic steel plates to each other through a collection of fine particles made of magnesium oxide or aluminum oxide. manufacturing method of the core to produce the iron core,
The first property of dispersing a metal compound that precipitates magnesium oxide or aluminum oxide by thermal decomposition in methanol, filling a container with a methanol dispersion of the metal compound, and dissolving or mixing in methanol, and the viscosity are higher than the viscosity of methanol. An organic compound having both a high second property and a third property having a boiling point higher than that of methanol and lower than the thermal decomposition temperature of the metal compound is mixed with the methanol dispersion of the metal compound, and the organic compound is mixed. A mixed solution of the compound and the methanol dispersion of the metal compound is prepared, and then a plurality of electromagnetic steel plates cut into the shape of an iron core are immersed in the mixed solution, and further, the plurality of electromagnetic waves are obtained from the mixed solution. The steel sheets are taken out, the temperature of the plurality of electromagnetic steel sheets is raised to the boiling point of methanol, and a film composed of a suspension in which a collection of fine crystals of the metal compound is deposited in the organic compound is formed on the plurality of electromagnetic steel sheets. The first step, which consists of the process of adsorbing to each electromagnetic steel plate,
Of the plurality of electromagnetic steel plates to which the film of the suspended material is adsorbed, a plurality of the electromagnetic steel plates constituting the iron core are laminated in a mold having the shape of the iron core, and then the metal is laminated. The mold is raised to the thermal decomposition temperature of the metal compound, a collection of fine particles made of magnesium oxide or aluminum oxide is deposited on each of the laminated electromagnetic steel sheets, and a pressurizing pressure gradually increased by a press machine is applied. The fine particles made of magnesium oxide or aluminum oxide are bonded to the surface of the electromagnetic steel plate, and the fine particles made of magnesium oxide or aluminum oxide are bonded to each other by adding the fine particles to the laminated electromagnetic steel plate. A second step in which the laminated electromagnetic steel plates are bonded to each other through joining to each other, and an iron core having a structure in which the laminated electromagnetic steel plates are bonded to each other is manufactured in the mold.
It consists of a third step of removing the iron core from the mold and magnetically annealing the iron core in a reducing atmosphere at a temperature of 750-820 ° C.
By continuously carrying out these three steps, an iron core having a structure in which laminated electromagnetic steel sheets are bonded to each other through bonding of fine particles made of magnesium oxide or aluminum oxide is produced, which is a method for manufacturing an iron core. ..

The method for manufacturing an iron core in the present invention has the following five features.
The first feature is that an electromagnetic steel sheet cut into the shape of an iron core is laminated in a mold, and the laminated electromagnetic steel sheet is further compressed to manufacture an iron core in the mold. This eliminates the need for the process of fixing the laminated electromagnetic steel sheets, and solves the first problem of the present invention described in paragraph 8.
The second feature is that an insulating layer is formed by a collection of fine particles made of magnesium oxide or aluminum oxide. This insulating layer has the properties of the fourth to eighth required for the insulating layer described in paragraph 7, and the second problem of the present invention described in paragraph 8 is solved. Further, since the insulation resistance of the insulating layer is two orders of magnitude higher than that of the conventional insulating layer, the eddy current flowing through the gap between the electromagnetic steel sheets is extremely small. The action and effect of the insulating layer will be described later.
The third feature is that the insulating layer is firmly bonded to the electromagnetic steel sheet and the laminated electromagnetic steel sheets are firmly bonded to each other. That is, since the electromagnetic steel sheet is manufactured in the rolling process, the flatness of the surface is excellent. Therefore, the bonding force based on the anchor effect between the conventional insulating layer formed on the electrical steel sheet and the electrical steel sheet is extremely small. However, fine particles made of magnesium oxide or aluminum oxide are directly bonded to the electrical steel sheet by frictional heat, and the fine particles are firmly bonded to each other by frictional heat, so that the insulating layer is firmly bonded to the electrical steel sheet. , Electromagnetic steel sheets are also firmly bonded to each other.
The fourth feature is that all the distortion of the electrical steel sheet is eliminated by one magnetic annealing. That is, the processing strain of the electrical steel sheet generated when a plurality of electrical steel sheets are stacked and cut into the shape of an iron core, and the fine particles made of magnesium oxide or aluminum oxide are bonded to the electrical steel sheet by frictional heat. Various strains such as stress strains of electrical steel sheets are eliminated by one magnetic annealing, and the holding power of electrical steel sheets is restored. This reduces the hysteresis loss of the iron core. Since the heat resistance of magnesium oxide or aluminum oxide is higher than that of the electrical steel sheet, there is no restriction on the temperature of magnetic annealing, so that all the strains of the electrical steel sheet can be eliminated by one magnetic annealing.
That is, in the method of manufacturing the iron core of the present invention, the planes of the electromagnetic steel sheets cut into the shape of the iron core are laminated in a mold, and fine particles made of magnesium oxide or aluminum oxide stacked on the entire surface of the electromagnetic steel sheet are formed. This is a manufacturing method in which an aggregate is deposited, the laminated electromagnetic steel sheet is compressed, and an iron core is manufactured in a mold. That is, as the pressure for pressurizing the laminated electromagnetic steel sheets increases, the following phenomenon occurs, and an iron core is manufactured in the mold. The fine particles of magnesium oxide or aluminum oxide that are deposited all at once by the thermal decomposition of the fine crystals of the metal compound are in contact with each other, but the contact portion is a weak bond based on the intramolecular force. Therefore, when a pressurized pressure is applied to the laminated electromagnetic steel sheets, the laminated structure of the accumulated fine particles is easily broken first. When the pressurizing pressure is further increased, the fine particles have a size of 40-60 nm, so that the fine particles have voids existing in the gaps between the electromagnetic steel sheets and voids existing in the gaps between the laminated electromagnetic steel sheets and the mold. Move to fill. When the pressurizing pressure is further increased, the voids disappear and the fine particles come into contact with each other. When the pressurizing pressure is further increased, the hardness of the fine particles is high, the heat resistance is high, and the compressive strength is high, so that the fine particles are not destroyed, the fine particles come into contact with each other, and frictional heat is generated at the contact portion. As a result, impurities in the contact portion between the fine particles and the contact portion between the fine particles and the electromagnetic steel sheet are vaporized, and the cleaned contact portion is firmly bonded by frictional heat. Further, when the pressurizing pressure is increased, both the compressive strength of magnesium oxide and the compressive strength of aluminum oxide are larger than the compressive strength of the electromagnetic steel plate. The repulsive force against the machine increases, and the pressurization by the press machine does not proceed. At this point, the pressurization by the press machine is stopped. If the repulsive force against the press is ignored and the pressing force is continuously increased, the magnetic steel sheet will eventually break. Therefore, there is no substantial restriction on the magnitude of the pressing force applied to the laminated electromagnetic steel sheets when the electromagnetic steel sheets are bonded to each other, and the pressing force can be applied to the laminated electromagnetic steel sheets according to the required strength of the iron core. can. As a result, the planes of the electrical steel sheets are firmly bonded to each other by the bonding between the fine particles. On the other hand, the fine particles also move to the voids between the side surface of the laminated magnetic steel sheet and the wall surface of the mold, the voids are filled with a collection of fine particles, and the fine particles are frictionally bonded to each other. As a result, the entire surface of the laminated electrical steel sheets, that is, the entire surface of the iron core is covered with a collection of friction-bonded fine particles.
The fifth feature is that all the materials used are inexpensive materials, and all three steps consist of extremely simple processing, so that the iron core can be manufactured at low cost. Further, by the first step, a coating film made of a suspended material can be simultaneously formed on a large number of electrical steel sheets. By the third step, a large number of iron cores can be magnetically annealed at the same time. The second step consists of three treatments, in which the three treatments are continuously carried out to manufacture the iron core in the mold. Therefore, if the dies are arranged on a belt made of steel at regular intervals, three processes are performed on each die, and the dies after each process are sequentially moved, the dies are continuous. The iron core is manufactured. Therefore, the iron core manufactured by this manufacturing method is inexpensive. This solves the third problem of the present invention described in paragraph 8. In the method for manufacturing the main iron core, magnetic annealing is performed in the third step, so that various processing strains applied to the electrical steel sheet are completely eliminated by one magnetic annealing.
Here, the action and effect of the fine particles of magnesium oxide and aluminum oxide forming the insulating layer will be described. _{Tin oxide SnO 2} is an insulating metal oxide having a hardness higher than that of magnesium oxide. However, in the tin oxide precipitated by the thermal decomposition of the metal compound, _{SnO X} deviating from the composition of _{SnO 2} is deposited at the same time, and the insulating property of _{SnO X} is significantly inferior to _{that of SnO 2.} Therefore, tin oxide precipitated by thermal decomposition of the metal compound cannot be used as fine particles forming an insulating layer.
The volume resistivity of magnesium oxide is 10 ¹⁷ Ω · cm, which is the most excellent insulating property among metal oxides and has a double-digit volume resistivity higher than that of synthetic resin. On the other hand, the magnesium oxide precipitated by the thermal decomposition of the magnesium compound is granular fine particles having a size of 40-60 nm, and the aggregates of the granular fine particles are piled up to insulate the magnetic steel sheet. Since the fine particles are granular, the volume is smaller than that of the fine particles, but there are many pores adjacent to the fine particles, which are close to the number of fine particles. These pores are occupied by air having a volume resistivity exceeding the volume resistivity of magnesium oxide. Therefore, the insulation resistance formed by the accumulated collection of magnesium oxide fine particles is such that the resistor made of magnesium oxide fine particles and the resistor made of air are connected in series to form an insulating resistance. Furthermore, the number of magnesium oxide fine particles and pores is extremely large. Therefore, the insulation resistance that insulates the electrical steel sheet is an order of magnitude higher than the insulation resistance formed by ^{the bulk magnesium oxide based on the volume resistivity of 10 17 Ω · cm.} Therefore, the eddy current flowing through the gap between the laminated electromagnetic steel sheets is extremely small.
In addition, it has a melting point of 2852 ° C. and is superior in heat resistance to electrical steel sheets. In addition, the Mohs hardness is as high as 5.5, which is harder than that of electrical steel sheets. Further, the compressive strength is as high as 1372 MPa, which is higher than the compressive strength of the magnetic steel sheet. Therefore, when the electromagnetic steel sheets covered with fine particles of magnesium oxide are laminated and the laminated electromagnetic steel sheets are compressed, there are gaps in the gaps between the magnetic steel sheets, and there are gaps between the laminated electromagnetic steel sheets and the mold. If there is, magnesium oxide fine particles move to fill the voids. When the voids disappear, the magnesium oxide fine particles come into contact with each other. Further pressurization generates excessive frictional heat in the contact portion. Since magnesium oxide has high heat resistance, high hardness, and high compressive strength, the magnesium oxide fine particles are bonded to each other by frictional heat without destroying the magnesium oxide fine particles. Similarly, when the voids disappear, the magnesium oxide fine particles come into contact with the surface of the magnetic steel sheet, and excessive frictional heat is generated at the contact portion. Since magnesium oxide has high heat resistance and high hardness, magnesium oxide fine particles are not destroyed and are bonded to electrical steel sheets by frictional heat. When further pressurized, the compressive strength of magnesium oxide is higher than the compressive strength of the electromagnetic steel plate, so that the repulsive force against the pressurization by the press increases and the pressurization by the press does not proceed. At this point, pressurization is stopped. As a result, in the mold, the insulating layer made of a collection of magnesium oxide fine particles bonded to each other is bonded to the electromagnetic steel sheet, and the electromagnetic steel sheets are bonded to each other via the insulating layer. Further, on the surface of the electromagnetic steel sheet laminated on the top and the surface of the electromagnetic steel sheet laminated on the bottom, magnesium oxide fine particles are bonded to the surfaces of both electromagnetic steel sheets by frictional heat, and the magnesium oxide fine particles rub against each other. Join with heat. Further, since the magnesium oxide fine particles are fine particles having a size of 40-60 nm, they also move to the side surface of the electromagnetic steel plate, and the collection of magnesium oxide fine particles moved to the side surface is compressed by contacting each other in the mold. Magnesium oxide fine particles are bonded to the electromagnetic steel plate on the side surface of the iron core by frictional heat, and magnesium oxide fine particles are bonded to each other by frictional heat. For this reason, a collection of magnesium oxide fine particles is laminated and bonded to the entire surface of the iron core, so that all liquids such as hot water, salt water, and high-temperature insulating oil are blocked by the collection of magnesium oxide fine particles, and the laminated electromagnetic waves are formed. The steel plate does not come into contact with the liquid. As a result, the iron core is provided with corrosion resistance and chemical resistance.
The coefficient of thermal expansion is 13.5 × 10 ^-6 / ° C, which is close to the coefficient of thermal expansion of electrical steel sheets of 11.2 × 10 ^{-6 / ° C.} On the other hand, since the magnesium oxide fine particles have a size of 40-60 nm, the thermal expansion and contraction of the magnesium oxide fine particles are extremely small. In addition, an extremely large number of granular magnesium oxide fine particles are evenly bonded to the surface of the electromagnetic steel plate, and the thermal expansion and contraction of the electromagnetic steel plate are constrained by the bonded magnesium oxide fine particles, and the bonded magnesium oxide fine particles are next to each other. The electromagnetic steel plate thermally expands or contracts at intervals of 40-60 nm. Therefore, the thermal expansion and contraction of the electrical steel sheet are extremely small. Therefore, even if a sudden temperature change such as magnetic annealing occurs, the fine particles of magnesium oxide that have been friction-bonded are not damaged. In addition, it is insoluble in liquids other than dilute hydrochloric acid, has corrosion resistance excluding dilute hydrochloric acid, and does not react with hot water, salt water, or high-temperature insulating oil. Furthermore, since it has extremely high heat resistance, it does not chemically change during magnetic annealing and does not cause seizure between electrical steel sheets.
Therefore, the magnesium oxide fine particles have the fourth to eighth properties described in paragraph 7.
Next, the volume resistivity of aluminum oxide is 10 ¹⁵ Ω · cm, which has the same insulating property as synthetic resin. On the other hand, the aluminum oxide precipitated by the thermal decomposition of the aluminum compound is granular fine particles having a size of 40-60 nm, and the aggregates of the granular fine particles are piled up to insulate the electrical steel sheet. Since the fine particles are granular, the volume is smaller than that of the fine particles, but there are many pores adjacent to the fine particles, which are close to the number of fine particles. These pores are occupied by air exceeding ^{10 17} Ω · cm, which has a volume resistivity that is two orders of magnitude larger than the volume resistivity of aluminum oxide. Therefore, the insulation resistance formed by the accumulated collection of aluminum oxide fine particles is such that the resistor made of aluminum oxide fine particles and the resistor made of air are connected in series to form an insulating resistance. Furthermore, the number of aluminum oxide fine particles and pores is extremely large. Therefore, the insulation resistance of the insulation of the electrical steel sheet, aluminum oxide consisting of the bulk volume resistivity of 3 orders of magnitude increases from insulation resistance to form on the basis of 10 ¹⁵ Ω · cm. Therefore, the eddy current flowing through the gap between the magnetic steel sheets is extremely small.
Further, it has a melting point of 2072 ° C. and is superior in heat resistance to an electromagnetic steel sheet. In addition, it has a Mohs hardness of 9, which is the highest among metal oxides, and is harder than electrical steel sheets. Further, the compressive strength is as high as 2910 MPa, which is higher than the compressive strength of the magnetic steel sheet. Therefore, when the electromagnetic steel sheets covered with the aluminum oxide fine particles are laminated and the laminated electromagnetic steel sheets are compressed, if there are voids in the gaps between the electromagnetic steel sheets, the aluminum oxide fine particles move to fill the voids. When the voids disappear, the aluminum oxide fine particles come into contact with each other, and excessive frictional heat is generated at the contact portion. Since aluminum oxide has high heat resistance and high hardness, the aluminum oxide fine particles are bonded to each other by frictional heat without destroying the aluminum oxide fine particles. Further, when the voids disappear, the aluminum oxide fine particles come into contact with the surface of the electromagnetic steel sheet, and excessive frictional heat is generated at the contact portion. Since aluminum oxide has high heat resistance and high hardness, aluminum oxide fine particles are not destroyed but are bonded to electrical steel sheets by frictional heat. When further compressed, the compressive strength of aluminum oxide is higher than the compressive strength of the electromagnetic steel plate, so that the repulsive force against the pressurization by the press increases and the pressurization by the press does not proceed. At this point, pressurization is stopped. As a result, in the mold, the insulating layer made of a collection of bonded aluminum oxide fine particles is bonded to the electromagnetic steel sheet, and the electromagnetic steel sheets are bonded to each other via the insulating layer. Further, on the surface of the electromagnetic steel sheet laminated on the top and the surface of the electromagnetic steel sheet laminated on the bottom, the aluminum oxide fine particles are bonded to the surfaces of both electromagnetic steel sheets by frictional heat, and the aluminum oxide fine particles rub against each other. Join with heat. Further, since the aluminum oxide fine particles are fine particles having a size of 40-60 nm, they also move to the side surface of the electromagnetic steel plate, and the collection of the aluminum oxide fine particles moved to the side surface is compressed by contacting each other in the mold. Aluminum oxide fine particles are bonded to the electromagnetic steel plate on the side surface of the iron core by frictional heat, and aluminum oxide fine particles are bonded to each other by frictional heat. For this reason, a collection of aluminum oxide fine particles is laminated and bonded to the entire surface of the iron core, so that all liquids such as hot water, salt water, and high-temperature insulating oil are blocked by the collection of aluminum oxide fine particles, and the laminated electromagnetic waves are formed. The steel plate does not come into contact with the liquid. As a result, the iron core is provided with corrosion resistance and chemical resistance.
The coefficient of thermal expansion is 7.2 × 10 ^-6 / ° C, which is close to the coefficient of thermal expansion of electrical steel sheets of 11.2 × 10 ^{-6 / ° C.} On the other hand, since the aluminum oxide fine particles have a size of 40-60 nm, the thermal expansion and contraction of the aluminum oxide fine particles are extremely small. In addition, an extremely large number of granular aluminum oxide fine particles are evenly bonded to the surface of the electromagnetic steel plate, and the thermal expansion and contraction of the electromagnetic steel plate are constrained by the bonded aluminum oxide fine particles, and the bonded aluminum oxide fine particles are next to each other. The electromagnetic steel plate thermally expands or contracts at intervals of 40-60 nm. Therefore, the thermal expansion and contraction of the electrical steel sheet are extremely small. Therefore, even if a sudden temperature change such as magnetic annealing occurs, the fine particles of magnesium oxide that have been friction-bonded are not damaged. In addition, it is an extremely stable metal oxide that is not affected by all acids and alkalis and has corrosion resistance that does not react with hot water, salt water, or high-temperature insulating oil. Furthermore, since it has extremely high heat resistance, it does not chemically change during magnetic annealing and does not cause seizure between electrical steel sheets.
Therefore, the aluminum oxide fine particles have the fourth to eighth properties described in paragraph 7.
Here, the method for manufacturing the iron core of the present invention will be described in detail. The manufacturing method for manufacturing the dust core comprises the following eight processes.
The raw material is inexpensive, and magnesium oxide or aluminum oxide is precipitated by a simple process of thermal decomposition, and the thermal decomposition temperature is as low as about 300 ° C. A metal compound having these three properties can be used as a raw material for magnesium oxide or aluminum oxide. Used as. On the other hand, in order to cover the electromagnetic steel plate with a collection of magnesium oxide fine particles or aluminum oxide fine particles, the first treatment disperses the metal compound in methanol and makes the metal compound into a liquid phase as a molecular state.
Next, in order to cover the electrical steel sheet with a collection of magnesium oxide fine particles or aluminum oxide fine particles, it is necessary to attach a methanol dispersion of a metal compound to the surface of the electrical steel sheet. Therefore, in the second treatment, the first property of dissolving or mixing in methanol, the second property of having a viscosity higher than that of methanol, and the boiling point of which is higher than the boiling point of methanol and lower than the thermal decomposition temperature of the metal compound. An organic compound having the three properties is mixed with a methanol dispersion to prepare a mixed solution. Most organic compounds are insulating liquids, except for extremely rare organic compounds. Further, in the third treatment, the electromagnetic steel sheets cut into the shape of a plurality of iron cores are immersed in the mixed liquid, and further, the plurality of electromagnetic steel sheets are taken out from the mixed liquid. In the fourth treatment, the temperature of a plurality of electrical steel sheets is raised to the boiling point of methanol, and a film composed of a suspension in which a collection of fine crystals of a metal compound is deposited in an organic compound is formed on each of the plurality of electrical steel sheets. It is attracted to the surface of the electrical steel sheet book. The vaporized methanol is recovered and reused.
Next, an iron core made of laminated magnetic steel sheets is manufactured in a mold. Therefore, in the fifth treatment, each of the plurality of electrical steel sheets adsorbed by the suspension as a film is laminated in a mold having the shape of an iron core. In the sixth treatment, the mold is heated to the thermal decomposition temperature of the metal compound, and a collection of fine particles made of magnesium oxide or aluminum oxide is deposited in the gaps between the laminated electromagnetic steel plates. The vaporized organic compound is recovered and reused. In the seventh treatment, a compressive load is applied to the laminated electromagnetic steel sheets, fine particles made of magnesium oxide or aluminum oxide are bonded to the surface of the electromagnetic steel sheets, and fine particles made of magnesium oxide or aluminum oxide are bonded to each other, and the fine particles are bonded to each other. The laminated electromagnetic steel sheets are bonded to each other through joining to each other, and an iron core is manufactured in a mold.
Finally, the processing strain of the electromagnetic steel sheet constituting the iron core is removed. In the eighth treatment, the iron core is removed from the mold, and the iron core is magnetically annealed in a reducing atmosphere at a temperature of 750-820 ° C. As the number of electrical steel sheets constituting the iron core increases, the compressive load applied to the electrical steel sheets increases and the compressive strain increases. Therefore, the temperature of magnetic annealing is increased according to the number of laminated electrical steel sheets.
The iron core manufactured by the above-mentioned manufacturing method has the following effects.
First, since the laminated electromagnetic steel sheets are bonded to each other through the bonding of fine particles made of magnesium oxide or aluminum oxide, the conventional process of fixing the laminated electromagnetic steel sheets becomes unnecessary. Therefore, the conventional problem that occurs when the laminated electromagnetic steel sheets are fixed does not occur at all. That is, since the electromagnetic steel sheet is manufactured by the rolling process, the flatness of the surface is excellent. Therefore, the bonding force based on the anchor effect between the conventional insulating film formed on the electrical steel sheet and the electrical steel sheet is extremely small. Therefore, in the method of manufacturing a conventional iron core, the conventional insulating film is easily peeled off from the surface of the electromagnetic steel sheet due to the impact when punching the laminated electromagnetic steel sheet, so that a process of fixing the laminated electromagnetic steel sheet is required. became. On the other hand, magnesium oxide or aluminum oxide in the present invention has three properties of high heat resistance, high hardness, and high compressive strength, and therefore, through frictional bonding between fine particles made of magnesium oxide or aluminum oxide. Electromagnetic steel plates can be bonded to each other.
Secondly, since the insulating layer made of a collection of fine particles made of magnesium oxide or aluminum oxide is formed by a collection of fine particles having high insulating properties and a collection of pores having high insulating properties, a bulk of magnesium oxide or aluminum oxide is formed. Since the insulation resistance is one digit or more higher than the insulation resistance made of aluminum, the eddy current flowing through the gaps between the electromagnetic steel plates is extremely small.
Thirdly, magnesium oxide or aluminum oxide has all the properties required for the insulating layer of the iron core as well as the insulating resistance.
Fourth, since all eight processes are simple processes using inexpensive materials, an inexpensive iron core can be manufactured. That is, the metal compound and the organic compound are general-purpose industrial chemicals. Further, the temperature at which the metal compound is thermally decomposed is as low as about 300 ° C., and the heat treatment cost is low. Furthermore, the iron core can be continuously manufactured. Therefore, the iron core can be manufactured at a processing cost close to the processing cost of the iron core manufactured by the conventional manufacturing method.
Fifth, since the electrical steel sheet cut into the shape of the iron core is laminated in the mold to manufacture the iron core, there are no restrictions on the shape and area of the electrical steel sheet and the number of laminated sheets. Further, since the compressive strength of the fine particles is higher than the compressive strength of the magnetic steel sheet, there is no restriction on the magnitude of the pressing force applied to the laminated electromagnetic steel sheet, and the pressing force is applied to the laminated electromagnetic steel sheet according to the required strength of the iron core. Add. Therefore, this manufacturing method is a general-purpose iron core manufacturing method.
Sixth, since the iron core is magnetically annealed after it is manufactured in the mold, all the processing strains of the electrical steel sheet can be efficiently removed by one magnetic annealing. Further, since the heat resistance of the fine particles is superior to that of the electrical steel sheet, there is no restriction on the temperature of magnetic annealing, and the holding force of the electrical steel sheet can be returned to the holding force of the electrical steel sheet before processing.
As described above, the method for producing the main iron core brings about the above-mentioned six functions and effects that are not found in the conventional method for producing the iron core.

In the method for producing an iron core described in paragraph 9, the metal compound is any magnesium compound made of magnesium octanate or magnesium naphthenate, or any aluminum compound made of aluminum benzoate or aluminum naphthenate. Yes, the organic compound is one kind of organic compound belonging to any one of carboxylic acid esters, glycols or glycol ethers, or a liquid monomer composed of a styrene monomer, and these three kinds of substances are used in paragraph 9. It is the method of manufacturing the iron core described in paragraph 9, wherein the iron core is manufactured according to the method of manufacturing the iron core described in 1.

As a metal compound that precipitates a metal oxide by thermal decomposition, there is a carboxylic acid metal compound. Among the carboxylic acid metal compounds, there is a carboxylic acid metal compound in which an oxygen ion constituting a carboxyl group serves as a ligand and approaches a metal ion to coordinate bond. In this carboxylic acid metal compound, the metal ion, which is the largest ion, approaches the oxygen ion and is coordinated, so that the distance between the two is shortened. As a result, the oxygen ion coordinate-bonded to the metal ion has the longest distance from the ion covalently bonded on the opposite side of the metal ion. When the carboxylic acid metal compound having such molecular structural characteristics exceeds the boiling point of the carboxylic acid constituting the carboxylic acid metal compound, the oxygen ion constituting the carboxyl group is covalently bonded to the ion on the opposite side of the metal ion. The bond is first split and decomposed into metal oxides and carboxylic acids. When the temperature is further raised, the carboxylic acid takes away the heat of vaporization and vaporizes, and after the vaporization of the carboxylic acid is completed, the metal oxide precipitates. Among these carboxylic acid metal compounds, as the carboxylic acid metal compound whose thermal decomposition is completed at a relatively low temperature of about 300 ° C., the metal acetate compound, the octanate metal compound, and the benzoate metal compound are in ascending order of the boiling point of the carboxylic acid. , There are metal naphthenate compounds. Therefore, the metal acetate compound, the metal octanoate compound, the metal benzoate compound and the metal naphthenate compound are metal compounds that precipitate metal oxides by thermal decomposition at a relatively low temperature.
On the other hand, the carboxylic acid metal compound in which the carboxylate anion is covalently bonded to the metal ion has the longest bond between the oxygen ion and the metal ion among the bonds between the ions, so that the metal is precipitated by thermal decomposition.
Among the carboxylic acid the magnesium compound, magnesium acetate, magnesium acetate tetrahydrate _Mg (CH 3 _COOH) is commercially available as ₂ · 4H 2 O. In the thermal decomposition of magnesium acetate tetrahydrate, the separation of crystalline water is completed at around 150 ° C., the anhydride is thermally decomposed at around 300 ° C., the thermal decomposition is completed at 450 ° C., and magnesium oxide MgO is precipitated. Further, magnesium benzoate, magnesium benzoate tetrahydrate _{Mg (C} 6 H 5 _COOH) commercially available as ₂ · 4H 2 O. Similar to the above magnesium acetate tetrahydrate, after the water of crystallization is separated, the anhydride is thermally decomposed, the thermal decomposition of the anhydrous is completed, and magnesium oxide is precipitated. The temperature at which magnesium oxide precipitates due to the thermal decomposition of the magnesium carboxylate compound is higher than the temperature at which the magnesium carboxylate compound decomposes into carboxylic acid and magnesium oxide at the boiling point of the carboxylic acid, and magnesium oxide precipitates after the carboxylic acid is vaporized. expensive. Therefore, as the magnesium carboxylate compound, magnesium octanoate Mg (C ₇ H ₁₅ COOH) ₂ and magnesium naphthenate Mg (C _n H _2n-1 COOH) ₂ are preferable. The boiling point of octanoic acid is 240 ° C., and magnesium octanoate is thermally decomposed at 300 ° C. in the atmospheric atmosphere to precipitate magnesium oxide. Further, in the thermal decomposition of the magnesium carboxylate compound, the temperature at which the thermal decomposition is completed is 50-60 ° C. lower in the atmospheric atmosphere than in the nitrogen atmosphere, and the heat treatment in the atmospheric atmosphere requires less heat treatment cost.
Among the aluminum carboxylate compounds, aluminum acetate precipitates atypical alumina by thermal decomposition. Further, aluminum octanate is commercially available as aluminum hydroxide octanate Al (C ₇ H ₁₅ COOH) ₂ (OH). Therefore, the carboxylic acid aluminum compound is decomposed into the carboxylic acid and aluminum oxide at the boiling point of the carboxylic acid, as the carboxylic acid aluminum compound aluminum oxide after the carboxylic acid vaporized is precipitated, aluminum benzoate Al (C ₆ H ₅ COOH) ₃ and naphthenate of aluminum _{Al (C n H 2n-1} COOH) 3 is preferred. The boiling point of benzoic acid is 249 ° C, and aluminum benzoate is thermally decomposed at 310 ° C in the air atmosphere to precipitate aluminum oxide. Further, in the thermal decomposition of the aluminum carboxylate compound, the temperature at which the thermal decomposition is completed is 50-60 ° C. lower in the atmospheric atmosphere than in the nitrogen atmosphere, and the heat treatment in the atmospheric atmosphere requires less heat treatment cost.
Incidentally, naphthenic acid, the main component is a carboxylic acid _C n _H 2n-1 COOH with carbon five-membered saturated ring, molecular weight Oyobi to 180-350, with a mixture of saturated fatty acids having a boiling point up to 140-370 ° C. be. Magnesium naphthenate _{Mg (C n H 2n-1} COOH) 2 or naphthenate of aluminum _Al a _{(C n H 2n-1 COOH} ) 3, the temperature was raised to 370 ° C., the boiling point of the high boiling component of naphthenic acid, furthermore, The temperature is raised to 430 ° C. to complete the vaporization of naphthenic acid, and magnesium oxide or aluminum oxide is precipitated.
Next, an organic compound having a first property of being soluble or miscible in methanol, a second property having a viscosity higher than that of methanol, and a third property having a boiling point higher than 65 ° C. and lower than 300 ° C. Used as the organic compound described in paragraph 9.
As such an organic compound, one kind of organic compound belonging to any one of carboxylic acid vinyl esters, acrylic acid esters, any ester consisting of methacrylic acid esters, glycols, glycol ethers, or styrene. There is a liquid monomer consisting of a monomer. Therefore, in the method for producing an iron core described in paragraph 9, any of these organic compounds is used as the organic compound. Most of the organic compounds are insulating except for extremely rare organic compounds.
Therefore, as the metal compound described in paragraph 9, any magnesium compound composed of magnesium octanate or magnesium naphthenate, or any aluminum compound composed of aluminum benzoate or aluminum naphthenate is used and described in paragraph 9. As the organic compound, one kind of organic compound belonging to any one of carboxylic acid esters, glycols or glycol ethers, or a liquid monomer composed of a styrene monomer is used to produce an iron core according to the production method described in paragraph 9. , The iron core is manufactured in the mold.

It is a figure which schematically illustrated the state which the electromagnetic steel sheets were bonded by the collection of the granular fine particles of magnesium oxide which were friction-bonded.

Embodiment 1
This embodiment relates to an organic compound in the method for producing an iron core described in paragraph 10 , and the organic compound has a first property of being soluble or miscible in methanol, a second property of having a viscosity higher than that of methanol, and a boiling point. Combines the third property of being higher than 65 ° C and lower than 300 ° C.
As such an organic compound, one kind of organic compound belonging to any one of carboxylic acid vinyl esters, acrylic acid esters, any ester consisting of methacrylic acid esters, glycols, glycol ethers, or styrene. There is a liquid monomer consisting of a monomer.
Carboxylic acid vinyl esters include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, vinyl myristate, vinyl palmitate, vinyl stearate, vinyl pipariate, and octyl. It is a vinyl carboxylate composed of vinyl acid acid, vinyl monochloroacetate, vinyl adipate, vinyl crotonate, vinyl benzoate and the like.
_{For example, vinyl acetate CH 3} COO-CH = CH ₂ is a carboxylic acid vinyl ester having a low boiling point, is soluble in methanol, has a higher viscosity than methanol, and has a boiling point of 72.7 ° C. Vinyl acetate is an ester obtained by reacting acetic acid with vinyl alcohol, is a raw material used for the synthesis of polyvinyl acetate, and is an inexpensive organic compound. Since vinyl acetate is easily polymerized by light or heat, a trace amount of a polymerization inhibitor (also referred to as a polymerization inhibitor) is added.
Further, monochloroacetic acid vinyl acetate Cl-CH ₂ COO-CH = CH ₂ is dissolved in methanol, has a higher viscosity than methanol, and has a boiling point of 136 ° C. Monomonochlorovinyl acetate is an inexpensive organic compound used as a cross-linking site for acrylic rubber.
Further, the acrylate esters are acrylate esters composed of methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate and the like.
For example, acrylates having a low boiling point include methyl acrylate CH ₂ = CH-COOCH _3, which is soluble in methanol, has a higher viscosity than methanol, and has a boiling point of 80 ° C. Methyl acrylate is an inexpensive organic compound used as a raw material for acrylic resins. Since methyl acrylate is a substance that easily polymerizes, a small amount of stabilizer is added.
Further, butyl acrylate CH ₂ = CH-COOC ₄ H ₉ is soluble in methanol, has a higher viscosity than methanol, and has a boiling point of 148 ° C. Butyl acrylate is an ester obtained by reacting acrylic acid with n-butanol, and is an inexpensive organic compound used as a raw material for fiber treatment agents, adhesives, paints, synthetic resins, acrylic rubbers, and emulsions. Methyl acrylate is a substance that easily polymerizes, and a trace amount of stabilizer is added.
The methacrylic acid esters are methacrylic acid esters composed of ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, alkyl methacrylate, tridecyl methacrylate, stearyl methacrylate and the like. ..
For example, methacrylic acid esters having a low boiling point include ethyl methacrylate H ₂ C = C (CH ₃ ) COOC ₂ H _5, which is soluble in methanol, has a higher viscosity than methanol, and has a boiling point of 117 ° C. Ethyl methacrylate is an inexpensive organic compound used as a raw material for pigments, paints, adhesives, fiber treatment agents, molding materials, and dental materials. Ethyl methacrylate is a substance that easily polymerizes, and a trace amount of stabilizer is added.
Further, nbutyl methacrylate CH ₂ C (CH ₃ ) COO (CH ₂ ) ₃ CH ₃ is dissolved in methanol, has a higher viscosity than methanol, and has a boiling point of 163.5 ° C. Butyl methacrylate is an inexpensive organic compound used as a raw material for paints, dispersants, and fiber treatment agents. Since n-butyl methacrylate is easily polymerized by light or heat, a small amount of a polymerization inhibitor is added.
Glycols are a kind of alcohol, and are compounds having a structure in which a hydroxy group is substituted for each of two carbon atoms of a chain aliphatic hydrocarbon. _{Ethylene glycol C 2} H ₄ (OH) ₂ is one of the glycols having a low boiling point, which is miscible with methanol, has a higher viscosity than methanol, and has a boiling point of 197.3 ° C. Ethylene glycol is an inexpensive organic compound widely used as a solvent, antifreeze solution, synthetic raw material and the like.
Further, diethylene glycol O (CH ₂ CH ₂ OH) ₂ is miscible with methanol, has a higher viscosity than methanol, and has a boiling point of 244.3 ° C. In addition to antifreeze, diethylene glycol is an inexpensive organic compound used in brake fluids, lubricants, inks, fabric softeners, fabric softeners, cork plasticizers, adhesives, paper, packaging materials, paints, etc. be.
Propylene glycol CH ₃ CHOHCH ₂ OH is miscible with methanol, has a higher viscosity than methanol, and has a boiling point of 188.2 ° C. Propylene glycol is used as a moisturizer, lubricant, emulsifier, antifreeze, intermediate material for plastics, solvent, etc., and also has excellent moisturizing and antifungal properties, so it improves the quality of pharmaceuticals, cosmetics, noodles, rice balls, etc. It is an inexpensive organic compound used in a wide range such as agents.
Further, dipropylene glycol [CH ₃ CH (OH) CH ₂ ] ₂ O is miscible with methanol, has a higher viscosity than methanol, and has a boiling point of 232.2 ° C. Dipropylene glycol is an inexpensive organic compound used as an intermediate raw material for polyester resins, hydraulic oils for hydraulic equipment, antifreeze, raw materials for printing inks, and the like.
Further, tripropylene glycol [CH ₃ CH (OH) CH ₂ ] ₂ O is miscible with methanol, has a higher viscosity than methanol, and has a boiling point of 265 ° C. Tripropylene glycol is used as a raw material for lubricating oils and cutting oils, raw materials for polyurethane / acrylic acid ester intermediates, paint / ink solvents, antifreezes, feed additives, intermediate raw materials for polyester resins, solvents for water-soluble oils, etc. It is an inexpensive organic compound.
Furthermore, glycol ethers have both an ether group and a hydroxyl group in one molecule, and are water, many organic solvents, and a solvent having high solubility of the resin, and most of the glycol ethers are dissolved in methanol. There are the following three types of glycol ethers. Ethylene glycol-based ethers and propylene glycol-based ethers are inexpensive materials used in paints, inks, dyes, photocopying liquids, cleaning agents, electrolytic solutions, soluble oils, hydraulic fluids, brake fluids, refrigerants, antifreeze agents, etc. Organic compound. Further, the dialkyl glycol is an inexpensive organic compound used in a reaction solvent, a separation extractant, a polymerization solvent, a decomposition prevention and stabilizer, an electrolytic solution of a battery or a capacitor, and the like.
For example, ethylene glycol-based ether having a low boiling point includes ethylene glycol monomethyl ether CH ₃ O- (CH ₂ CH ₂ O) -H, which is soluble in methanol, has a higher viscosity than methanol, and has a boiling point of 124.5 ° C. be. Further, ethylene glycol monoisopropyl ether (CH ₃ ) ₂ CHO- (CH ₂ CH ₂ O) -H is dissolved in methanol, has a higher viscosity than methanol, and has a boiling point of 141.8 ° C.
Ethylene glycol-based ethers with a high boiling point include triethylene glycol monobutyl ether C ₄ H ₉ O- (CH ₂ CH ₂ O) _3- H, which dissolves in methanol, has a higher viscosity than methanol, and has a boiling point of 271. .2 ° C. Diethylene glycol mono 2-ethylhexyl ether C ₂ H _5- C ₄ H ₉ CHCH ₂ O- (CH ₂ CH ₂ O) _2- H is dissolved in methanol, has a higher viscosity than methanol, and has a boiling point of 272 ° C. be.
Furthermore, propylene glycol-based ethers with a low boiling point include propylene glycol monomethyl ether CH _3- CH ₃ O- (CH ₂ CHO) _2- H, which dissolves in methanol, has a higher viscosity than methanol, and has a boiling point of 121 ° C. be.
Moreover, the high boiling point of propylene glycol ether, tripropylene glycol monobutyl ether _CH 3 _-C 4 _H 9 _- There are (CH 2 _CHO) 3 -H, dissolved in methanol, having a higher methanol viscosity, boiling point 274 ℃.
Further, the low boiling point dialkyl glycol, there are ethylene glycol dimethyl ether _{CH 3 O- (CH 2 CHO)} -CH 3, was dissolved in methanol, having a higher methanol viscosity, boiling point of 85.2 ° C..
In addition, diethylene glycol dibutyl ether C ₄ H ₉ O- (CH ₂ CH ₂ O) _2- C ₄ H ₉ has a high boiling point, is dissolved in methanol, has a higher viscosity than methanol, and has a boiling point of 274 ° C. Is.
Further, the styrene monomer C ₆ H ₅ CH = CH ₂ is a liquid monomer miscible with methanol, having a viscosity higher than that of methanol, and having a boiling point of 145 ° C. Styrene monomer is an inexpensive organic compound that can be used as a raw material for synthetic resin materials such as expanded polystyrene, acrylonitrile / styrene, acrylonitrile / butadiene / styrene, and unsaturated polyester, including polystyrene. Since the styrene monomer is easily polymerized, a small amount of a polymerization inhibitor is added.
As described above, the above-mentioned three properties of an organic compound belonging to any of carboxylic acid vinyl esters, acrylic acid esters, and any ester consisting of methacrylic acid esters, glycols, and glycol ethers have the above-mentioned three properties. There is an organic compound that also has. Further, the styrene monomer has the above-mentioned three properties. Therefore, these organic compounds are used as organic compounds in the method for producing an iron core described in paragraph 9.

Example 1
This embodiment is an example of manufacturing an iron core in which electromagnetic steel sheets are bonded to each other by joining fine particles of magnesium oxide to each other. As the electrical steel sheet, a non-oriented electrical steel sheet (for example, 35H210, which is a product of Nippon Steel Corporation and has a thickness of 0.35 mm) was used. Non-oriented electrical steel sheets are widely used as iron cores of transformers except large transformers and distribution transformers and iron cores of various rotating machines. The direction of magnetization of the electrical steel sheet and the magnitude of iron loss are properties peculiar to the electrical steel sheet, and any electrical steel sheet can be used. Magnesium octanate (for example, a product of Fuji Film Wako Pure Chemical Industries, Ltd.) was used as the magnesium compound. Further, as the organic compound, ethylene glycol having a boiling point of 197 ° C. and a viscosity of 20 ° C. of 20 mPas corresponding to 34 times the viscosity of methanol (for example, a product of Nippon Shokubai Co., Ltd.) was used.
The non-oriented electrical steel sheet was cut into a disk having a diameter of 4.9 cm to prepare 40 disks. Next, 14 g (corresponding to 0.1 mol) of magnesium octanate was dispersed in 1 liter of methanol, and the dispersion was filled in a container. Further, 300 cc of ethylene glycol was mixed in the container to prepare a mixed solution having a viscosity 19 times the viscosity of methanol. Forty discs were immersed in this mixed solution, and then the 40 discs were picked up and heated to 65 ° C. to vaporize methanol. Next, 20 discs vaporized with methanol were laminated on a cylinder having an inner diameter of 5 cm and a wall thickness of 2 cm and made of alumina that could be divided into four parts. Further, the mold is heated to 240 ° C. at a heating rate of 20 ° C./min, further heated to 300 ° C. at a heating rate of 40 ° C./min, left at 300 ° C. for 1 minute, and then at room temperature. Cooled down to. After that, an alumina disk was placed on the laminated disk, and a weight of 100 kg was further placed (pressurization pressure ^{corresponds to 5 kg / mm 2} ), and the mixture was left for 1 minute. After this, the mold was divided, the alumina disk was removed, and the sample was taken out. Finally, the sample was left in a heat treatment apparatus having a nitrogen atmosphere at 750 ° C. for 1 hour, and then slowly cooled. Two such samples were prepared.
First, the surface insulation resistance was measured with an insulation resistance tester. Since it exceeded 20 MΩ, it was found that the insulation resistance of the surface was high.
Next, the iron loss was measured with a simple iron loss measuring instrument manufactured by Toei Kogyo Co., Ltd. The iron loss of the sample at a magnetic flux density of 1.6 T was only 2.3 W / kg. According to the manufacturer's catalog, the iron loss of the electromagnetic steel sheet was 2.10 W / kg or less, so that the iron loss was close to that of the electromagnetic steel sheet. Therefore, the insulating property of the collection of fine particles of magnesium oxide is extremely high, and the eddy current flowing through the gap between the magnetic steel sheets is small. It can also be seen that the holding force of the electrical steel sheet was restored by magnetic annealing.
Further, the sample was subjected to thermal shock by the air tank thermal shock tester which gives a temperature change from -30 ° C to 120 ° C, but the appearance of the sample did not change.
Next, the sample was immersed in 5% salt water for 1 hour, but the appearance of the sample did not change.
Further, a sample obtained by continuously performing a thermal shock test and a salt water immersion test was dropped from a height of 2 m onto the floor, but the sample was not damaged.
Furthermore, the sample was cut in the thickness direction, and a plurality of parts on both the surface and the cut surface were observed with an electron microscope. As the electron microscope, an extremely low acceleration voltage SEM manufactured by JFE Techno Research Co., Ltd. was used. This device can observe the surface with an extremely low acceleration voltage from 100 V, and has the feature that the surface of the sample can be directly observed without forming a conductive film on the sample.
First, the secondary electron beam between 900 and 1000 V of the backscattered electron beam was taken out and image-processed, and the surface and the cross section were observed. Granular fine particles having a size of 40-60 nm were evenly deposited on the surface, and the fine particles were bonded to each other. In the cross section, 15 to 20 fine particles overlapped and joined to fill the gap between the electrical steel sheets. Next, the energy and its intensity of the characteristic X-rays were image-processed, and the types of elements constituting the granular fine particles and their distribution states were analyzed. Since both magnesium atoms and oxygen atoms were uniformly present and no uneven distribution was observed, the particles were granular particles made of magnesium oxide. The results are schematically shown in FIG. 1 is an electromagnetic steel sheet, and 2 is granular fine particles of magnesium oxide.

Example 2
This embodiment is an example of manufacturing an iron core in which electromagnetic steel sheets are bonded to each other by joining fine particles of aluminum oxide to each other. As the electrical steel sheet, the same non-oriented electrical steel sheet as in Example 1 was used. Aluminum benzoate (for example, a product of Mitsuwa Chemical Co., Ltd.) was used as the aluminum compound. Further, as the organic compound, the same ethylene glycol as in Example 1 was used.
The non-oriented electrical steel sheet was cut into discs having a diameter of 4.9 cm in the same manner as in Example 1, and 40 discs were prepared. Next, 39 g (corresponding to 0.1 mol) of aluminum benzoate was dispersed in 1 liter of methanol, and the dispersion was filled in a container. Further, 300 cc of ethylene glycol was mixed in the container to prepare a mixed solution. Forty discs were immersed in this mixed solution, and then the 40 discs were picked up and heated to 65 ° C. to vaporize methanol. Next, 20 discs vaporized with methanol were laminated on the same mold made of alumina as in Example 1. Further, the mold is heated to 250 ° C. at a heating rate of 20 ° C./min, further heated to 310 ° C. at a heating rate of 40 ° C./min, left at 310 ° C. for 1 minute, and then at room temperature. Cooled down to. After that, an alumina disk was placed on the laminated disk, a weight of 100 kg was further placed, and the mixture was left for 1 minute. After this, the mold was divided, the alumina disk was removed, and the sample was taken out. Finally, the sample was left in a heat treatment apparatus at 750 ° C. in a nitrogen atmosphere for 1 hour, after which the sample was slowly cooled. Two such samples were prepared.
First, the surface insulation resistance was measured with an insulation resistance tester. As in Example 1, since it exceeded 20 MΩ, it was found that the insulation resistance on the surface was high.
Next, the iron loss was measured in the same manner as in Example 1. The iron loss of the sample at a magnetic flux density of 1.6 T was only 2.3 W / kg. From this result, the insulating property of the collection of fine particles of aluminum oxide is extremely high, and the eddy current flowing through the gap of the electromagnetic steel sheet is small. It can also be seen that the holding force of the electrical steel sheet was restored by magnetic annealing.
Further, the sample was subjected to thermal shock by the air tank thermal shock tester which gives a temperature change from -30 ° C to 120 ° C, but the appearance of the sample did not change.
Next, the sample was immersed in 5% salt water for 1 hour, but the appearance of the sample did not change.
Further, a sample obtained by continuously performing a thermal shock test and a salt water immersion test was dropped from a height of 2 m onto the floor, but the sample was not damaged.
Finally, as in Example 1, both the surface and the cut surface of the sample were observed with an electron microscope. Granular fine particles having a size of 40-60 nm were evenly deposited on the surface, and the fine particles were bonded to each other. In the cross section, 15 to 20 fine particles overlapped and joined to fill the gap between the electrical steel sheets. Next, the types of elements constituting the granular fine particles and their distribution states were analyzed. Since both aluminum atoms and oxygen atoms were uniformly present and no uneven distribution was observed, the particles were granular fine particles made of aluminum oxide.

As explained above, the iron loss of the iron core is close to that of the electrical steel sheet. From this result, a collection of fine particles made of magnesium oxide or aluminum oxide formed extremely high insulation resistance in the gaps between the electrical steel sheets. Further, by magnetic annealing, all the processing strains in the electrical steel sheet were eliminated, and the holding force of the electrical steel sheet was restored. Since the electromagnetic steel sheets were firmly bonded by joining the fine particles to each other, they had thermal impact resistance. Further, since the iron core is covered with a collection of fine particles in which fine particles are bonded to each other, it has corrosion resistance to salt water. Iron cores with such excellent performance are manufactured continuously by continuous processing using inexpensive raw materials. Therefore, according to the method for manufacturing an iron core of the present invention, an iron core having superior performance to that of a conventional iron core can be manufactured at a low cost as in the conventional iron core.

1 Electrical steel sheet 2 Granular fine particles of magnesium oxide

Claims (2)

A plurality of electromagnetic steel plates cut in the shape of the core, are laminated through a collection of particles comprising a magnesium oxide or aluminum oxide, compresses magnetic steel sheets and the stacking, said fine particles of said magnesium oxide or the aluminum oxide It is composed of bonding to the surface of an electromagnetic steel plate, bonding fine particles made of magnesium oxide or aluminum oxide to each other, and bonding the electromagnetic steel plates to each other through a collection of fine particles made of magnesium oxide or aluminum oxide. manufacturing method of the core to produce the iron core,
The first property of dispersing a metal compound that precipitates magnesium oxide or aluminum oxide by thermal decomposition in methanol, filling a container with a methanol dispersion of the metal compound, and dissolving or mixing in methanol, and the viscosity are higher than the viscosity of methanol. An organic compound having both a high second property and a third property having a boiling point higher than that of methanol and lower than the thermal decomposition temperature of the metal compound is mixed with the methanol dispersion of the metal compound, and the organic compound is mixed. A mixed solution of the compound and the methanol dispersion of the metal compound is prepared, and then a plurality of electromagnetic steel plates cut into the shape of an iron core are immersed in the mixed solution, and further, the plurality of electromagnetic waves are obtained from the mixed solution. The steel sheets are taken out, the temperature of the plurality of electromagnetic steel sheets is raised to the boiling point of methanol, and a film composed of a suspension in which a collection of fine crystals of the metal compound is deposited in the organic compound is formed on the plurality of electromagnetic steel sheets. The first step, which consists of the process of adsorbing to each electromagnetic steel plate,
Of the plurality of electromagnetic steel plates to which the film of the suspended material is adsorbed, a plurality of the electromagnetic steel plates constituting the iron core are laminated in a mold having the shape of the iron core, and then the metal is laminated. The mold is raised to the thermal decomposition temperature of the metal compound, a collection of fine particles made of magnesium oxide or aluminum oxide is deposited on each of the laminated electromagnetic steel sheets, and a pressurizing pressure gradually increased by a press machine is applied. The fine particles made of magnesium oxide or aluminum oxide are bonded to the surface of the electromagnetic steel plate, and the fine particles made of magnesium oxide or aluminum oxide are bonded to each other by adding the fine particles to the laminated electromagnetic steel plate. A second step in which the laminated electromagnetic steel plates are bonded to each other through joining to each other, and an iron core having a structure in which the laminated electromagnetic steel plates are bonded to each other is manufactured in the mold.
It consists of a third step of removing the iron core from the mold and magnetically annealing the iron core in a reducing atmosphere at a temperature of 750-820 ° C.
A method for manufacturing an iron core, which comprises a structure in which electromagnetic steel sheets laminated through bonding of fine particles made of magnesium oxide or aluminum oxide are bonded to each other by continuously carrying out these three steps. In the method for producing an iron core according to claim 1, the metal compound is any magnesium compound made of magnesium octanate or magnesium naphthenate, or any aluminum compound made of aluminum benzoate or aluminum naphthenate. The organic compound is a liquid monomer composed of one kind of organic compound belonging to any one of carboxylic acid esters, glycols or glycol ethers, or a styrene monomer, and these three kinds of substances are used for claiming. The method for manufacturing an iron core according to claim 1, wherein the iron core is manufactured according to the method for manufacturing an iron core according to item 1.