JP2005340706A - Laminated adhesion core and its production process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated adhesion core excellent in dimensional precision by preventing adhesive from remaining on the lamination surface, and to provide its production process. <P>SOLUTION: When the laminated adhesion core is produced through a step for punching a soft magnetic steel plate and laminating a plurality punched soft magnetic steel plates, a step for impregnating the laminate with thermosetting adhesive, a step for forming the laminate by constraining it with a forming jig, and a step for drying and baking the laminate, drying and baking are carried out such that the end face of the laminate does not touch a peripheral device. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a laminated adhesive core and a method for manufacturing the same.

  As for a punching method of a thin steel strip that becomes an iron core of an electric device or the like, a so-called caulking method is performed in which two strip-shaped electric iron plates are overlapped, and both the iron plates are crimped and integrated at the same time. In this method, since the method of punching iron cores one by one is inefficient, a plurality of electric iron plates as iron core materials are stacked and punched at the same time.

  However, the above method has a problem that a thin material having a plate thickness of 0.15 mm or less cannot be sufficiently caulked because the crimping strength of the caulking portion is weak.

  Therefore, as a method for manufacturing a laminated core that solves the above-described problems of the technology, for example, as described in Patent Document 1, a method of laminating a press core, impregnating an adhesive, and drying and curing is performed.

  However, after the adhesive is heated (dried) and cured, the adhesive remains around the core lamination surface, and this adhesive may cause irregularities, which may deteriorate the dimensional accuracy. Also, in applications such as reactors, a combination of multiple cores, a gap material is sandwiched between the joint surfaces of the cores, and the core and the gap material are fixed with an adhesive. If the adhesive remains in the adhesive, there is a problem that sufficient core strength cannot be obtained when the adhesive for adhering and fixing to the gap material is dried and solidified.

For this, align and fix the core impregnated with adhesive on the bonding jig, and lightly wipe the adhesive on the surface of the core with waste cloth, paper towel, liquid absorbent material, etc. before drying and baking. It is a commonly practiced method to take or scrape lightly with a solid piece having a rubber piece, plastic piece, wood piece, metal piece, or other straight portion.
JP2003-257761A

  However, in the above method, the adhesive around the core lamination surface cannot be removed sufficiently, and there are still problems such as deterioration of dimensional accuracy and deterioration of core strength due to the remaining adhesive.

  The present invention has been made in view of the above points, and provides a laminated adhesive core excellent in dimensional accuracy by preventing the adhesive on the laminated surface from remaining and a manufacturing method thereof.

  The present inventors have studied to solve the above-described problems of the prior art. As a result, the adhesive remaining around the core lamination surface is remarkably recognized on the surface that comes into contact with peripheral devices such as molding jigs, release materials, etc., and no adhesive remains on the non-contact surface. It was found that this tendency varies depending on how the laminate is placed in the molding jig.

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

  [1] A step of punching a soft magnetic steel sheet and laminating a plurality of sheets, a step of impregnating the laminate with a thermosetting adhesive, and a laminate after the step are restrained by a molding jig When the laminated adhesive core is manufactured by the step of molding by this and the step of drying and baking the laminated body constrained by the molding jig, the laminated end face of the laminated body at the time of the drying and baking treatment is A method for manufacturing a laminated adhesive core, which is not in contact with a peripheral device.

  [2] A step of forming a laminate by constraining a plurality of punched soft magnetic steel plates with a molding jig, and a thermosetting adhesive for the laminate constrained by the molding jig When the laminated adhesive core is manufactured by the impregnation step and the step of drying and baking the laminated body after the step, the laminated end surface of the laminated body at the time of the drying and baking treatment is not in contact with the peripheral device. A method for producing a laminated adhesive core, comprising:

  [3] A laminated adhesive core produced by the method for producing a laminated adhesive core according to [1] or [2].

  According to the present invention, a laminated adhesive core having excellent dimensional accuracy can be obtained. Since it is possible to sufficiently remove the adhesive around the core lamination surface, it is possible to omit conventional processes such as wiping and scraping with a solid material, thereby improving production efficiency. Furthermore, since the laminated adhesive core of the present invention has good product properties such as core dimensions, core strength, and magnetic properties, it is very useful as a material for iron cores, transformers, reactors and the like of electrical equipment.

  Below, the manufacturing method of the lamination | stacking adhesive core of this invention is demonstrated in detail.

  In the present invention, a soft magnetic steel plate is used, and first, the soft magnetic steel plate is punched into a predetermined shape to obtain a pressed loose core. At this time, from the viewpoint of productivity, it is desirable to continuously punch a steel strip or a hoop-shaped soft magnetic steel sheet using a press machine.

  Next, a plurality of press bulk cores are laminated to form a laminate. At this time, for example, it is preferable to form a predetermined number of laminated bodies by temporarily restraining and temporarily fixing with a simple pressing jig, rubber band or the like so that individual punched steel plates do not fall apart. The temporary restraining and temporary fixing do not need to be strongly pressed and stopped because the adhesive is infiltrated between the laminated layers by impregnation, and may not be dissociated.

  Thus, by performing temporary fixing, it becomes difficult to be affected by the surface tension due to the adhesive impregnation in the molding process with the molding jig later, and the dimensional accuracy is improved. This temporary fixing is not essential and can be appropriately selected according to the use conditions of the laminated adhesive core.

  Next, the laminate is impregnated with a thermosetting adhesive. At this time, the adhesive used is a thermosetting adhesive. In particular, a thermosetting adhesive of acrylic resin or epoxy resin is preferable. For example, when used in automotive parts, etc., since it is used while undergoing a heat cycle from below zero to about 150 ° C, it must have adhesive strength against temperature changes, and as a one-component acrylic system as an adhesive It is preferable to use an adhesive or an epoxy adhesive.

  As a method for impregnating the laminate in the adhesive, there are a) a method of vacuum impregnation, a) a method of impregnation at normal pressure (atmospheric pressure), and any of them may be used. However, when the laminate is put into the adhesive and impregnated, the laminate and the adhesive are put in a tray or the like, and a) by vacuum impregnation, the laminate needs to be completely immersed in the adhesive. is there. Also, in the method of a) impregnation under normal pressure, when using the capillary phenomenon, the laminated surface of the core is aligned so that it protrudes upward, and the liquid level of the adhesive is 2 with respect to the height of the core. 1 to 1/10. When immersed in an adhesive so as to cover the entire laminate, the adhesive penetrates from all sides, and air accumulates in the central portion of the laminate, adversely affecting the core strength, such as variations in the strength of the product core. Therefore, it is important to set the liquid level of the adhesive so that the adhesive rises from below the laminated adhesive core and pushes air between the laminated cores upward.

  Next, after the impregnation, it is preferable to recover excess adhesive from the impregnated core in order to effectively use the thermosetting adhesive used at the time of impregnation again. As a collection method, forcibly collecting by air blow or the like in addition to natural fall.

  Next, the laminated body is taken out from the impregnated body, and after excess adhesive is dropped from the laminated body, the laminated body is molded by restraining it with a molding jig. At this time, it is preferable to use a release material, and a fluororesin coating plate can be used as the release material. By using a fluororesin coating plate as a mold release material, it is more rigid than a single mold release material that is not coated with fluororesin, and the dimensional accuracy is improved. Moreover, compared with the release material which was used by applying a release agent (liquid) to an iron plate or the like, drying and baking each time, it is possible to increase production efficiency. Furthermore, it can be used multiple times and is very effective in maintaining the accuracy of the core, while at the same time reducing costs.

  The material of the molding jig body is not particularly limited, but it is an important component that determines dimensional accuracy, so it can be used repeatedly with metal, has the desired hardness and rigidity, and ensures the perpendicularity of the product core. It is desirable to have a material with sufficient accuracy to do so. It is preferable that the fluororesin coating plate has the same shape as the core shape because it facilitates alignment when set on a jig. Further, the release material is preferably used so as to be sandwiched between the laminate and the molding jig on all surfaces where the molding jig is in contact with the laminate.

  Next, the laminated body restrained by the forming jig is dried and baked to obtain a laminated adhesive core in which the soft magnetic steel plates are completely bonded. At this time, it is assumed that the stack end face of the stack is not in contact with the peripheral device. This is a feature of the present invention and is the most important requirement. This will be described in detail below.

  As described above, the adhesive remaining around the core lamination surface is markedly left on the surface in contact with the molding jig, mold release material, drying furnace inner wall, etc. It was found that no adhesive remained, and that this tendency was different depending on how the laminate was placed in the molding jig. The present invention is obtained based on the above knowledge, and it is important that the laminated end face of the laminate is not in contact with the peripheral device, and the adhesive is obtained by making the laminated end face and the peripheral device non-contact. It is intended to prevent the remaining. The peripheral device is a device used for performing drying and baking processes, and examples thereof include a drying furnace, a molding jig, and a release material. And not being in contact with these means that the laminated end faces of the laminate are not completely in contact with each other, including surface contact and point contact.

  FIG. 1 shows an embodiment of the present invention. FIG. 1 shows a state of a molding jig 2 installed in a drying furnace and a laminated body 1 fixed in the jig during drying and baking processes. In FIG. 1, the laminate 1 is constrained by the molding jig 2 when the lamination surface A (two upper and lower surfaces) comes into contact with the molding jig. It is placed vertically in the drying oven so that According to FIG. 1, the laminated end faces B1 and B2 are not in contact with any surface of the molding jig, so that drying and baking can be performed with the laminated end face in contact with the surface of the molding jig. When performed, the surface tension prevents the adhesive from remaining on the contact portion and drying and solidifying. That is, the adhesive generally shrinks when dried and solidified. By utilizing this shrinkage phenomenon caused by non-contact, it is possible to prevent the adhesive from remaining on the surface of the core laminate, and it is possible to obtain a laminate adhesive core having excellent dimensional accuracy.

  FIG. 2 shows another embodiment of the present invention. As in FIG. 1, this shows the state of the molding jig 2 installed in the drying furnace during the drying and baking process and the laminated body 1 fixed in the jig, and an adhesive is applied to the laminated end face B1. Used when In FIG. 2, the laminate 1 is constrained by the molding jig 2 when the lamination surface A (two upper and lower surfaces) comes into contact with the molding jig. The molding jig has the lamination surface A perpendicular to the drying furnace bottom surface. It is placed horizontally in the drying furnace with the shaft 3 as a support. According to FIG. 2, the laminated end faces B1 and B2 are not in contact with any surface of the molding jig, so that the laminated end face is in contact with the molding jig surface for drying and baking. When performed, it is possible to prevent the adhesive from remaining on the contact portion due to surface tension and to dry and solidify, and to obtain a laminated adhesive core having excellent dimensional accuracy. Moreover, since the laminated body 1 is installed so that the lamination | stacking end surface B1 may become horizontal with the drying furnace bottom face, the adhesion nonuniformity in the lamination | stacking end surface B1 can be prevented.

  Moreover, for example, an electric furnace, a hot air drying furnace, an induction heating furnace, or the like can be used for the drying and baking treatment. The drying and baking treatment at this time is usually preferably performed at 100 to 200 ° C. for 10 minutes or longer. However, the present invention is not limited to this, and the conditions for drying the adhesive are appropriately selected so that the temperature and holding time of the core itself satisfy the conditions necessary for curing the adhesive.

  After the drying and baking treatment, when excess adhesive is attached around the core, it is preferable to remove the excess adhesive around the core using a cutter knife or the like in order to improve the dimensional accuracy of the core. .

  The laminated adhesive core of this invention is obtained by the above. In addition, there is no limitation in particular about the order of an above-described process, For example, it is also possible to replace an impregnation process and a shaping | molding process and to perform an impregnation after shaping | molding.

  In the present invention, the composition of the soft magnetic steel sheet is not particularly limited. However, considering the properties after core forming such as magnetic properties, it is preferable to use a high silicon steel plate or amorphous thin steel plate having a Si content of 2.5 mass% or more. In addition, even a soft magnetic steel sheet having an insulating film, for example, a soft magnetic steel sheet without an insulating film such as amorphous is the target steel sheet of the present invention. Further, there is no special limitation on the plate thickness, but it is particularly suitable for a soft magnetic steel plate having a thickness of 0.15 mm or less, which is difficult to be caulked. In the present invention, such a very thin steel plate can be used without any problem. .

Invention Example A 6.5% silicon steel plate having a thickness of 0.1 mm and a width of 50 mm was used, and punching was performed by shearing with a press at a punching length (cutting length) of 20 mm. Next, it is laminated so as to have a rectangular parallelepiped core shape with a stacking thickness of 30 mm, and an acrylic thermosetting adhesive is used as the thermosetting adhesive for the obtained laminate, and the pressure is 0.05 atm or less in a vacuum impregnation apparatus. A thermosetting adhesive was impregnated under the conditions. Next, the laminated body was molded by restraining it with a molding jig to produce a laminated adhesive core. At this time, a fluororesin coated steel sheet having a thickness of 0.3 mm was used as a release material, and the jig was sandwiched to provide sufficient rigidity and accuracy. Then, as shown in FIG. 1, before charging the drying furnace, the laminated adhesive core is restrained in such a way that it is fixed so that only two places on the laminated surface are in contact with the surface of the jig, and the laminated surface is perpendicular to the bottom surface of the drying furnace. Then, they were fixed and aligned so as to be, and then dried and baked at 120 ° C. for 45 minutes.

Comparative Example In the same manner as in the inventive example, punching, lamination, adhesive impregnation and molding were performed to produce a laminated adhesive core. Then, as shown in FIG. 3, before the drying furnace is charged, the laminated adhesive core is constrained so that only two places on the laminated surface are in contact with the surface of the jig, and the laminated surface sandwiches the release material. It was fixed and aligned so as to be horizontal with the bottom of the drying furnace, and then dried and baked at 120 ° C. for 45 minutes.

  With respect to the laminated adhesive cores of the present invention example and comparative example obtained as described above, 100 cores were manufactured and the dimensional accuracy was compared. As for dimensional accuracy, first, the dimension was measured with calipers, and then the error was calculated. The results obtained are as follows.

Example size error of the present invention: +0.06 to +0.18
Comparative example dimensional error: +0.3 to +0.8
From the above, it can be seen that a laminated adhesive core having excellent dimensional accuracy is obtained in the present invention.

  On the other hand, in the comparative example, since the adhesive remained in the contact portion and dried and solidified, the dimensions varied.

  Very useful as a material for iron cores, transformers, reactors, etc.

It is a figure which shows the embodiment of the laminated body fixed in the jig | tool for shaping | molding installed in the drying furnace at the time of the drying and baking process of this invention, and a jig | tool. It is a figure which shows the other embodiment of the laminated body fixed in the jig | tool for shaping | molding installed in the drying furnace at the time of the drying and baking process of this invention, and a jig | tool. It is a figure which shows the embodiment of the laminated body fixed in the jig | tool for shaping | molding installed in the drying furnace at the time of the conventional drying and baking process, and a jig | tool.

Explanation of symbols

1 Laminate
2 Molding jig
3-axis
4Releasing material A Laminated surface B1, B2 Laminated end surface

Claims (3)

A process of stacking a plurality of soft magnetic steel sheets after punching,
Impregnating the laminate with a thermosetting adhesive;
A step of molding the laminate through the step by restraining with a molding jig;
When manufacturing a laminated adhesive core by a process of drying and baking the laminated body constrained by the molding jig,
A method for producing a laminated adhesive core, wherein a laminated end face of the laminated body at the time of drying and baking is not in contact with a peripheral device. A step of molding a laminate by restraining a plurality of punched soft magnetic steel plates with a molding jig;
Impregnating a laminate constrained by the molding jig with a thermosetting adhesive;
When producing a laminated adhesive core by a process of drying and baking treatment on the laminated body that has undergone the process,
A method for producing a laminated adhesive core, wherein a laminated end face of the laminated body at the time of drying and baking is not in contact with a peripheral device.   A laminated adhesive core manufactured by the method for producing a laminated adhesive core according to claim 1 or 2.

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