JP2005210817A - Electromagnetic stacked iron core and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a stacked iron core that makes it possible to fix unit iron cores in a short period of time and efficiently without deteriorating magnetic characteristics and that has good magnetic characteristics. <P>SOLUTION: The electromagnetic stacked iron core is manufactured by fixing with heat in a mold the stacked iron core formed by stacking a plurality of sheet-like iron cores 23. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electromagnetic laminated core forming method in which thin plates formed by punching a belt-shaped iron core material with a die are sequentially laminated in a die, and the laminated thin plates are integrated by heating and pressing, and an electromagnetic such as a motor or a transformer. It relates to a laminated iron core.

  In recent years, there has been a demand for miniaturization and high performance of OA equipment, audio and video equipment, and in response to this, the gap between the motor core (also called armature or core) and the magnet is reduced. Or improve. Motors installed in personal digital assistants have been used for vibration generation motors and small motors such as hinge actuator motors. The main size is 6 mm or less in diameter, the members are smaller, and the accuracy of parts is higher. It is coming.

  Products equipped with small cameras in electronic devices such as mobile phones and personal digital assistants are beginning to appear on the market. Most of these small cameras have 110,000 or 350,000 pixels. The number of pixels of small cameras mounted on mobile phones has been increasing year by year, and has taken in the strongholds of the lower pixel count class in the digital camera market. In such a social market environment, images taken with a small camera mounted on a mobile phone have come to be communicated over the Internet, and have begun to spread worldwide. As with digital cameras, mobile phone cameras have begun to request autofocus and optical zoom functions. A zoom motor or a focus motor mounted on a mobile phone camera is required to have a motor diameter of φ4 mm to φ2.5 mm and a height of about 5 mm. The size is about half the size of conventional products. As a zoom or focus drive motor, a small DC motor or a stepping motor is suitable. However, since the size is small, it must be designed so as to output the maximum torque at the desired size.

  When it comes to small-diameter motors, the assembly accuracy and torque characteristics of parts become major problems. Under such circumstances, the conventional method of laminating the motor cores and the conventional pack caulking method have such a point that there is not enough space to form a pack. Therefore, the movement to use the bonding method used before the pack caulking method has started.

  A conventional electromagnetic laminated iron core is obtained by laminating an electromagnetic steel sheet into a sheet-like iron core by shearing or punching, and further fixing by bolting, caulking, welding, adhesion, or the like. The electromagnetic laminated iron core is formed with insulation on the surface after the lamination is fixed, and a coil is wound on the insulation to form a motor iron core or a transformer iron core. The conventional manufacturing method needs to be examined for an electromagnetic laminated iron core of a small motor.

  A common manufacturing method among conventional examples is pack caulking (see, for example, Patent Document 1). Protrusions in the thickness direction were provided on the back of a sheet-shaped iron core formed by continuous punching of a strip-shaped iron core material (magnetic steel plate) supplied in a hoop shape, and punched before the sheet-shaped iron core. The convex part of the projection of the sheet-shaped iron core is press-fitted and fitted into the concave part on the back side of the projection of the previous sheet-shaped iron core. With this pack caulking, it is possible to laminate and fix sheet-like iron cores, but with caulking, it is difficult to strongly fix and the stacking is shifted. In particular, since the iron core is a magnetic circuit component, the deterioration of the magnetic characteristics may not be ignored. Since the protrusion of the crimped portion is formed, the metal composition of the core becomes finer and the magnetic characteristics are deteriorated. In order to prevent deterioration, the core may be annealed, but the surface is easily rusted and the cost is increased, so annealing is not used except in special cases. In pack caulking, a gap is formed between the sheet-like iron cores when the protrusions are press-fitted and the magnetic properties of the electromagnetic laminated iron core are deteriorated.

  Bolt tightening is often used for large laminated iron cores and is not often used for small motors. In bolt tightening, it is necessary to provide a through hole in the laminated iron core to pass the bolt. The magnetic characteristics of the bolt embedded in the through hole of the laminated iron core and the magnetic characteristics of the laminated iron core are different. Or a gap may be formed between the bolt and the laminated iron core. Therefore, when the through hole is provided in the laminated iron core, the magnetic properties of the laminated iron core are deteriorated. On the other hand, since it is a bolt, the fastening is firm.

  Welding has been increasingly used because it does not require caulking projections or the like. When the laminated iron core is fixed by welding, the magnetic properties of the laminated iron core may deteriorate due to thermal distortion in the welded portion. It is used because it has less deterioration in magnetic properties than pack caulking, but there are problems such as an increase in equipment and an increase in the cost of the laminated core. Therefore, recently, a method for forming an iron core by laminating thin plates without gaps and laser welding in a mold has been considered. Because it is in the mold, oil for press etc. is used, it becomes a mist, it becomes dirty of laser welding optical system, etc., and it is difficult to maintain and manage laser welding joints in daily production There is a case. In the case of a small motor, the size of the laminated iron core is small, so the welded part melts into the inside by laser welding, which adds a large thermal strain, and the deterioration of the magnetic properties of the iron core is worse than expected. There is. For this reason, it is important to make the thermal distortion of welding into the minimum range (for example, refer to patent documents 2 and 3).

  In the case of adhesion and fixing with an adhesive, the sheet-like iron core does not have a magnetically deteriorated portion such as a pack caulking portion. Adhesion fixation is a method in which a liquid adhesive is poured and fixed between a sheet-like iron core and a sheet-like iron core using a capillary phenomenon. In the case of adhesive fixation with an adhesive, it is not possible to ensure a certain uniform gap or to harden the adhesive in the middle because it is in a heated state when it is infiltrated into the gap by capillary action while being heated under pressure. It is difficult to evenly pour the adhesive. In particular, the adhesive fixing by the adhesive has a problem that the adhesive remains on the laminated surface of the laminated iron core, and the treatment of the remaining adhesive is particularly difficult in the case of a small motor core.

  Further, when the adhesive is applied to the iron core, the iron cores are laminated, and the adhesive is cured and fixed, it is necessary to control the amount applied. When the amount is large, there is a problem that the adhesive protrudes from the end surfaces of the laminated cores, and the processing of the adhesive is particularly difficult in the case of a small motor core (see, for example, Patent Document 4).

  Hereinafter, a conventional iron core of a motor will be described with reference to the drawings.

  FIG. 7 is a structural diagram of a conventional motor with a brush, and FIG. 8 shows an iron core of the motor. 7 and 8, 33 is an iron core, 34 is a shaft, 35 is an insulator, 36 is a magnet, 37 is a coil, 38 is a frame, 39 and 40 are sintered bearings, 41 is a commutator, and 42 is It is a brush.

  The structure configured as described above will be described below.

  A shaft 34 is press-fitted and fixed in a hole provided in a central portion of a motor core 33 in which silicon steel plates are laminated. Since the shaft pressure input becomes large when the laminated thickness is large, the diameter of the hole provided in the central portion of the iron core 33 is controlled in terms of design dimensions so that the shaft does not bend.

An insulator 35 formed by resin molding into an iron core shape is inserted into the iron core 33 with the shaft press-fitted and fixed from both end surfaces of the iron core 33. The iron core 33 and the resin insulator 35 can be inserted with a minute gap. In order to hold the resin insulator 35 on the iron core 33, a holding portion must be formed. There are usually two cases. One example is a case where a minute projection is provided on the insulator side corresponding to the tooth portion of the iron core 33, and the retaining force is given by the minute projection. In the second example, since the shaft 34 is fixed to the iron core 33, the insulator is held by the shaft fitting portion of the insulator when the iron core is mounted by providing a portion fitted to the shaft 34 on the insulator side. The The iron core 33 has a press burr and the like, and the resin insulator 35 is not in a completely intimate contact state, but is mounted to such an extent that it does not hinder the winding work. In addition, in order to locally reduce the insulator molding thickness on the iron core surface side of the teeth and to ensure the moldability of the insulator, even if the thickness of the outer periphery of the teeth of the iron core is increased, the core and insulator There is a gap for insertion.

  A commutator 41 is press-fitted into a shaft 34 with an iron core 33 fitted with an insulator 35. The commutator 41 includes a commutator holder, a plurality of commutator pieces, and an insulating ring. As the commutator 41 of the small motor, two kinds of assembly commutator and mold commutator are generally used. When the small motor is about the size of a small DC motor used in portable electronic equipment and about 4 mm in diameter, an assembly commutator is generally used frequently.

  Further, the coil 37 is wound around the iron core 33 insulated by the insulator 35, the energized portion of the coil 37 is attached to the terminal portion of the commutator piece, and is made conductive with solder, and the ring-shaped varistor is further connected to the commutator piece. The motor's armature winding assembly is made in a conductive connection with the terminal portion of the motor.

  Next, the curling arc surface of the commutator piece of the amateur winding assembly is lapped to clean the entire amateur winding assembly.

  A sintered bearing 39 is fixed to the center of the bottom of the bottomed cylindrical frame, and a magnet 36 is attached to the inner peripheral side of the outer peripheral hanging portion of the frame 38. The magnet 36 is magnetized. The cleaned armature winding assembly shaft 34 is inserted into the sintered bearing 39, and the bracket with the brush 42 is attached to the frame 38 to assemble the motor.

  The brush 42 usually indicates an assembly of a brush and a brush terminal, but since the brush uses a precious metal member, in order to reduce the material as much as possible, the sliding brush part and the outside of the motor are provided. The member is divided into the lead brush terminal part.

  The thickness of the brush 42 is 0.05 mm to 0.1 mm, and the brush terminal is fixed to the bracket by pressure contact with a brush terminal having a plate thickness larger than that of the brush. Since the brush terminal is thick, it is firmly fixed to the bracket. The brush is made of a grad material using precious metal.

The iron core 33 of the motor shown in FIG. 8 is manufactured by a pack method in which a silicon steel plate is punched out by a press machine, irregularities are formed on the surface of the plate-shaped iron core, and the irregularities are stacked in a mold. The position of the pack 43 is formed in a tooth portion having a substantially central radius of the iron core. However, if the motor is reduced, the tooth width of the iron core is correspondingly reduced and the pack diameter is reduced. In the conventional motor, the pack diameter is about 2 mm to 1.2 mm.
JP 2000-125519 A (page 5-6, FIG. 1, FIG. 2, FIG. 7) JP-A-7-112296 (page 3, FIG. 1) Japanese Patent Laid-Open No. 11-290965 (7th page, FIG. 2) JP-A-7-170699 (2nd page, FIG. 1)

However, as described in the background art, when the motor becomes a small-diameter motor, the assembly accuracy and torque characteristics of the components become serious problems. The problems of the electromagnetic laminated iron core of the motor are as follows.
(1) Packing caulking, welding such as laser welding, and bolting greatly deteriorate the magnetic properties of the core.
(2) In pack caulking, since a core is small in a small motor, the caulking portion cannot be formed.
(3) In a laminated core of a small motor, in welding joints such as laser welding, the welding heat is not conducted to the entire core, so the temperature of the core rises, the joint is not stable, and the internal melting of the joint such as welding burns Occurs and the deterioration becomes significant.
(4) In the penetration fixing of the adhesive, the penetration state of the adhesive varies depending on the location, and the core lamination thickness varies, making it impossible to manage the thickness. Furthermore, it is impossible to remove the adhesive remaining on the cross-sectional surface.

  In view of the above problems, an object of the present invention is to provide an electromagnetic laminated iron core with little deterioration in magnetic characteristics.

  In order to solve the above-described problems, in the present invention, a silicon steel plate used for a motor iron core is punched with a press machine, and plate-like pieces of sheet iron cores are stacked and laminated. Since the pack method shown in the conventional example has a large deterioration in magnetic characteristics, the iron core is heated in a state where the cores are overlapped, and the coated core is adhered to the surface of the plate material, and the laminated core is manufactured.

  According to the first aspect of the present invention, it is possible to obtain a laminated iron core of an electromagnetic steel sheet by fixing the iron cores to each other with an insulating coating that produces an adhesive force coated on the surface of the electromagnetic steel sheet by high-frequency induction heating in a mold. For this reason, the advantageous effect that the unit iron core can be fixed efficiently in a short time without deteriorating the magnetic characteristics and a method for obtaining an electromagnetic laminated iron core with good magnetic characteristics can be established.

  Further, according to the invention of claim 2, the advantageous effect of separating the iron cores by the protrusions can be obtained by fixing the iron cores with the insulating coating that produces the adhesive force coated on the surface of the electromagnetic steel sheet, and the magnetic properties are deteriorated. Therefore, the advantageous effect that the unit core can be fixed efficiently in a short time and an electromagnetic laminated core with good magnetic properties can be obtained.

  According to a third aspect of the invention, the adhesive for fixing the iron cores to each other with an insulating coating that produces an adhesive force coated on the surface of the magnetic steel sheet in the mold is an epoxy thermosetting resin, and the motor An advantageous effect is obtained that it can be used when exposed to high temperatures.

  According to the invention described in claim 4, the adhesive for fixing the iron cores to each other with an insulating coating that produces an adhesive force coated on the surface of the electromagnetic steel sheet in the mold is an acrylic thermoplastic resin, The advantageous effect that it can be used is obtained.

According to the first aspect of the present invention, a magnetic steel sheet having an insulating coating that generates an adhesive force by heating and pressing is punched into a sheet-like iron core, and a predetermined number of the obtained sheet-like iron cores are laminated. In a method of manufacturing a laminated core that is later heated and pressurized to be integrated, the sheet core punched out by the upper die and the lower die is laminated in the lower die, and a die for punching is arranged above the lower die. A high-frequency induction heating device for induction heating is arranged at the center of the lower die, a work holding die is arranged on the lower side of the lower die, and a punching die and a work holding die are arranged above and below the high-frequency induction device. A method for producing an electromagnetic laminated iron core comprising: providing a heat insulating material that cuts off heat conduction to the sheet, and bonding and integrating the laminated sheet-like iron cores heated by the high-frequency induction heating device at the center of the lower mold And Without deteriorating the magnetic properties, it can be fixed in a short time a and efficiently unit iron core, it is possible to obtain satisfactory lamination iron core of the magnetic properties. A laminated iron core of magnetic steel sheets can be obtained by fixing the iron cores with an insulating coating that produces an adhesive force coated on the surface of the magnetic steel sheets by high-frequency induction heating in the mold. A unit iron core can be fixed efficiently in time, and a method for obtaining an electromagnetic laminated iron core with good magnetic properties can be established.

  The invention according to claim 2 of the present invention is characterized in that the laminated iron core is separable by providing protrusions on the sheet-like iron core for every predetermined number of sheets. This is a method, and has an effect of separating the iron cores from each other at the protrusion by fixing the iron cores with an insulating coating that produces an adhesive force coated on the surface of the electromagnetic steel sheet.

  The invention according to claim 3 of the present invention is an electromagnetic laminated iron core produced by the manufacturing method according to claim 1 or 2, wherein the insulating coating is formed of an epoxy thermosetting resin. Yes, an epoxy-type thermosetting resin is used to fix the iron cores to each other with an insulating coating that produces an adhesive force coated on the surface of the magnetic steel sheet in the mold, and is used when the motor is exposed to high temperatures. It has the effect of being able to.

  According to a fourth aspect of the present invention, there is provided an electromagnetic laminated iron core produced by the manufacturing method according to the first or second aspect, wherein the insulating coating is formed of an acrylic thermoplastic resin. The adhesive that adheres the iron cores to each other with an insulating coating that produces an adhesive force coated on the surface of the magnetic steel sheet in the mold is an acrylic thermoplastic resin, and has an effect that it can be used in a general environment.

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

  FIG. 1 is a sectional view of a small motor. The overall configuration of the small-diameter motor in Embodiment 1 will be described.

  As shown in FIG. 1, the small-diameter motor includes a frame 2 in which a drive magnet 1 is attached to an inner peripheral surface, and a rotor 3 disposed in the frame 2. The rotor 3 includes a shaft 4 and an armature 5. The rotor 3 is rotatably supported at both ends by a sintered bearing 6 provided on the frame 2 and a sintered bearing 8 provided on the bracket 7. The frame 2 is formed in a bottomed hollow cylindrical shape. A bracket 7 fitted to the opening is provided in the opening of the frame 2 in which the drive magnet 1 is disposed on the inner periphery of the cylindrical portion. The frame 2 is manufactured by deep drawing a magnetic steel plate. The bracket 7 is also manufactured by press drawing a magnetic steel plate, but is formed integrally with resin molding for mounting the brush portion.

  In the armature 5, a coil 10 is wound around a tooth portion of a laminated core 9 that is press-fitted and fixed to the shaft 4. However, in order to insulate the laminated core 9 from the coil 10, the surface of the core 9 is insulated with an electrodeposition coating 11. The commutator 12 is attached to the shaft 4 and is electrically connected to the coil 10. The commutator 12 has three terminal portions 13 for connecting the coil 10. The commutator is an assembly commutator.

Two brushes 14 are slidably engaged with the commutator 12. The brush 14 is held by a brush holder 15 that is integrally attached to the bracket 7. The brush holder 15 is integrally formed with the metallic bracket 7 by an insulating material such as an insulating synthetic resin or a synthetic resin containing glass fiber. A pair of connection terminals 16 are attached to the brush holder 15. The brush 14 is electrically connected to the connection terminal 16. The end 17 of the connection terminal 16 is inserted into a takeout port 18 (also referred to as a cut hole) provided in the brush holder 15 and protrudes outward from the outer surface of the motor.

  In a small-diameter motor, if a current is passed from the connection terminal 16 through the brush 14 to the coil 10 via the commutator 12, a magnetic field is generated in the iron core 9 and rotated in the magnetic field generated by the drive magnet 1. Since the child 3 is placed, a torque acts on the rotor 3, and the rotor 3 rotates. In order to stabilize the rotation, a current can be continuously supplied to a necessary coil by using a brush and a commutator, and the shaft 4 rotates to obtain an output.

  The shaft 4 protruding from the bottomed side of the frame 2 is the output side of the motor. Depending on the form to be used, the output side of the shaft 4 may be attached with some member such as when knurling the gear portion on the shaft 4 or press-fitting a resin gear.

  The other bearing 8 rotatably supports the non-output side of the shaft 4. In the vicinity of the sintered bearing 8, the end surface of the shaft 4 is processed into a spherical shape so as to receive a thrust direction load, and the end surface is in contact with the thrust plate 19. Since the thrust plate 19 is thin and made of a resin material, in order to receive a thrust load, it is necessary to receive the thrust plate 19 with a material having a little higher strength. In the embodiment, it is received by a metal bracket 7. The sintered bearing 8 is press-fitted and fixed in a recess provided in the bracket 7.

  The bearing configuration on the sintered bearing 8 side is a so-called pivot bearing. The load in the thrust direction is constituted by a pivot bearing of a ball portion at the tip of the shaft and a thrust plate. A low sliding resin material is used for the thrust plate 19.

  The bracket 7 is made of metal in order to have a motor shielding effect. That is, the metal plate material is subjected to drilling or bending by pressing. In a DC motor having a motor of about 1 W, it is often a resin bracket. In a small motor such as a camera lens driving motor of a mobile phone as in the present application, a metal plate is formed from a strength relationship in order to make the bracket as thin as possible. Furthermore, taking into account electric noise and the like, the bracket is formed of a metal plate so as to be clear even when judged from the fact that the application is a communication device. Since the metal plate is naturally conductive, it must be insulated from the place where electricity flows. That is, the brush holder 15 that also serves as an insulation is integrally formed with the bracket 7 by resin molding. The brush holder 15 is formed with a take-out port 18 for leading the electrical wiring to the outside of the motor, and the end 17 is inserted into the take-out port 18 so that the motor can be led out from the inside to the outside. The end portion 17 is formed at one end of the connection terminal 16, and the brush 14 is attached to the other end. The connecting terminal 16 has a mounting portion of the brush 14 and the end portion 17 at a position 90 degrees away from the shaft axis. That is, by soldering the end 17 that is exposed to the outside of the motor and connecting it to a lead wire or a flexible printed board, the resin of the brush holder 15 is melted by soldering heat, the insertion force is reduced, and the brush position is moved. This is to prevent the sliding position of the brush and commutator from shifting and impairing the reliability. In addition, the distance through which the solder heat conducts the connection terminal 16 is increased so that the solder heat is not easily transmitted to the brush 14. Therefore, the connection terminal 16 is large enough to dissipate heat, and further, a terminal portion is formed at a position away from the brush 14. The sintered bearing 8 is press-fitted and fixed to a cylindrical portion obtained by processing the bracket 7 into a recess.

Since it is a direct current motor, as an electrical input, for example, at DC 2.8V, a voltage is applied to the -terminal and the + terminal, that is, 0V is applied to the -terminal and 2.8V is applied to the + terminal. To do. There are basically two connection terminals (a pair). A brush is attached to each connection terminal. Basically, even if there are many commutator pieces of the motor, there are two brushes 14.

  The brush holder 15 is integrally formed on the bracket 7, and after inserting the thrust plate into the concave portion at the center of the bracket 7, the sintered bearing 8 is press-fitted. Next, the connection terminal 16 to which the brush 14 is fixed in advance is inserted into the bracket 7 with the brush holder 15 into the take-out port 18 of the brush holder 15.

  Next, the motor core and the insulation process will be described.

  The motor core 9 is made by punching a silicon steel plate with a press machine, making a core block by superposing a specified number of plate-like core pieces, and pressing the superposed iron core block in the mold. An iron core is manufactured by heating and fixing the coated adhesive layer to the surface of the plate material and laminating it. The adhesive layer coated on the surface of the plate has a thermosetting type and a thermoplastic type, and the fixing method to the member of the iron core is different depending on whether it is thermosetting or thermoplastic. In the case where the shaft and the iron core are fixed as in the present application, one having a thermosetting adhesive layer is used. Although there is no problem with thermoplasticity, thermosetting is preferable when there is a process in which heat is applied to the laminated iron cores.

  The shaft 4 is press-fitted and fixed in a hole provided in the central portion of the motor core 9 laminated with silicon steel plates, and an assembly of the core 9 into which the shaft 4 is press-fitted is manufactured. In the state of the assembly, an insulating treatment film is applied to the iron core 9 and the shaft 4 of the motor. At this time, if the entire shaft 4 is subjected to an insulation treatment, there is a hindrance to the sliding clearance of the bearing portion and the insertion of the commutator. Therefore, an insulation treatment film is partially applied to the shaft 4. That is, the both end sides of the shaft are masked so that no insulation treatment film is attached, and the insulation treatment film is attached to the shaft side of the base portion with the iron core 9. The surface of the iron core 9 is covered with an insulating film over the entire surface.

  In the case of a small-diameter motor, in order to improve torque characteristics, it is necessary to increase the laminated thickness of the iron core. Then, since the total height of the motor is determined, the gap between the commutator 12 and the iron core 9 must be reduced. The gap between the iron core 9 and the commutator 12 is made as small as possible so that the coil can be arranged, so that a space for winding the coil is secured under the commutator holder, and sufficient insulation is secured.

  FIG. 2 is a sectional view of a mold. A description will be given with reference to FIG.

  In order to shear or punch the electromagnetic steel sheet into a sheet-like iron core, a punch 20 and a die 21 are installed on the upper part of the mold, and the strip-shaped electromagnetic steel sheet 22 supplied in a hoop shape is continuously punched to obtain a sheet shape. An iron core 23 is formed. A ring-shaped die 21 is embedded in the center of the lower part of the upper shape, and the punched sheet-shaped iron core 23 remains in the die 21. Subsequently, the punched sheet-shaped iron core 23 moves downward in the die 21 while moving downward by the thickness of the plate. That is, the sheet-shaped iron core is laminated in the die 21.

  A high-frequency heating device is incorporated in an intermediate portion between the upper mold and the lower mold. Since the high-frequency heating device is used to increase the temperature of the product, when it is configured in a mold, heat transfer is suppressed by a heat insulating material so that heat is not transmitted to other members. Under the upper die 21, heat transfer to the upper die is reduced through a heat insulating material 24. When heat is transferred to the upper mold, the punching dimension changes due to thermal expansion, and an iron core with a stable dimension cannot be obtained. In order to reduce heat transfer to the lower mold, a heat insulating material 25 is also installed in the lower mold.

A high-frequency heating device is disposed between the heat insulating materials 24 and 25, but a heating coil 26 of the high-frequency heating device is disposed in the mold. The controller section is near the press controller so that it can be controlled in conjunction with the die punching process. That is, the high frequency heating coil of the high frequency heating device is built in the mold.

  The high-frequency heating coil 26 is a coil spirally wound in a cylindrical shape. When an alternating current is passed through the heating coil 26, a high-density eddy current is generated in the vicinity of the surface of the iron core that is the object to be heated. Heat the surface of the iron core with heat.

  As shown in FIG. 3, a principle explanatory coil diagram of high frequency induction heating is shown. As shown in the figure, when a coil 28 is wound around a round bar-shaped metal (object to be heated) 27 and an alternating current is passed through the heating coil 28, the surface of the object 27 is heated and becomes red. come. This is because the high-frequency magnetic flux generated by the high-frequency current penetrates the object to be heated 27 and induces a very high density eddy current, whereby the surface of the object to be heated 27 is heated. In this way, current is induced in the metal placed off the coil 28 and the metal is heated. In the present invention, a heating coil is disposed in the mold so as to exert this induction heating phenomenon on the iron core in the mold. This eddy current is stronger as it gets closer to the surface of the object to be heated, and becomes weaker exponentially as it goes inside, so the center part of the iron core is suitable because it has a hole due to the position of the motor shaft. Works.

  By installing the coil as described in FIG. 3 in the mold shown in FIG. 2, the iron core can be heated in the mold. In FIG. 2, the sheet-like iron cores in the upper die 21 are stacked and moved into the hole of the core hardening zone at the center. When the iron core moves to the central die 29, the laminated iron core corresponding to the laminated thickness is heated by the heating coil 26, and the coating adhesive layer applied to the surface of the iron core is fixed and laminated. Make the iron core.

  A silicon steel plate is punched with a press machine, and a specified number of sheet-shaped iron cores are overlapped to make a core block. In order to separate such a laminated core, the process of projecting 30 is used as a separation surface. Form. The iron core is separated by the protrusion formed by the protrusion protrusion 30, and even if heated, the iron core is fixed to the protrusion and can be easily separated.

  Further, the laminated and fixed iron core takes the place of the heat insulating material 25 by the upper punching process, and a ring-shaped die 31 is embedded in the center portion of the lower die, and the lower die 31 is perforated. At 32, the iron core is held. The iron core laminated and fixed is taken out from the through-hole 32. It is an iron core with a predetermined number of layers.

  There are methods as shown in FIGS. 4 to 6 depending on the method of forming the protrusions for separating the laminated iron cores. Each separation method will be described.

  Since the insulation coating that generates adhesive force is applied on both sides of the surface of the electromagnetic steel sheet, if there is no ingenuity to separate anything between the laminated iron core blocks, the blocks will be stuck, so separate each block There is a need. A block represents one of the iron cores on which the motors are stacked, and one block is an iron core used for one motor.

  In FIG. 4, a separator 46 is provided between the blocks. A separation protrusion 44 is formed on the surface of the electromagnetic laminated iron core that is the block 45. The protrusions 44 on the surface of the block 45 are provided with a separator 46 so that the blocks do not directly contact each other. Since this separator 46 must pass through the mold, it has the same shape as the outer diameter of the sheet-like iron core. In order to share the mold, the separator 46 is a single sheet-like iron core. The separator 46 is in a sheet state having no protrusions. The protrusion 44 of the block 45 is in contact with the separator 46. Since this separator 46 cannot be used as a laminated iron core, it will be discarded and it can be said that it is a waste.

  The block 45 is made of a laminated core by melting and fixing and fixing an insulating film that generates an adhesive force of the sheet-like iron core by high-frequency induction heating in the mold.

  Since the separator exists in the middle of the block in the block position of FIG. 4, there is no problem even if the protrusion position is the same at the top and bottom of the block.

  In FIG. 5, a separator 47 is provided between the blocks as in FIG. No separation protrusion is formed on the surface of the electromagnetic laminated iron core which is the block 48, and the separation protrusion 49 is formed on the separator side. A separator 47 is provided so that the blocks 48 do not directly contact each other. Since this separator 47 must pass through the mold, it has the same shape as the outer diameter of the sheet-like iron core. In order to share the mold, the separator 47 is a sheet-like iron core. The block 48 is in contact with the protrusion 49 of the separator 47. Since this separator 47 cannot be used as a laminated iron core, it is discarded.

  In the block 48, a laminated core is formed by melting and fixing and fixing an insulating film that generates an adhesive force of the sheet-like core by high frequency induction heating in the mold.

  The protrusion positions of the separator 47 in FIG. 5 are formed at different positions in the vertical direction due to the protrusion process. In FIG. 5, the electromagnetic laminated iron core has no protrusions, which is suitable when the resin core is used to insulate the iron core from the coil.

  In FIG. 6, there is no separator and the blocks directly contact each other. A separation protrusion 51 is formed on the surface of the electromagnetic laminated iron core that is the block 50. The protrusions 51 on the surface of the block 50 can be separated even if the blocks directly contact each other because the contact portion is the tip of the protrusion. Since FIG. 6 does not have a separator as in FIGS. 4 and 5, a laminated iron core can be manufactured without waste.

  The block 50 is made of a laminated core by melting and fixing and fixing an insulating film that generates an adhesive force of the sheet-like iron core by high-frequency induction heating in the mold.

  The adhesive layer coated on the surface of the plate has a thermosetting type and a thermoplastic type, and the fixing method to the member of the iron core is different depending on whether it is thermosetting or thermoplastic. In the case where the shaft and the iron core are fixed as in the embodiment, one having a thermosetting adhesive layer is used. Although there is no problem with thermoplasticity, thermosetting is preferable when there is a process in which heat is applied to the laminated iron cores.

  The surface of the electrical steel sheet has an insulating coating that generates adhesive force. There are thermosetting and thermoplastic materials. If the insulating coating that generates adhesive force is an epoxy-based thermosetting resin, it is a high heat type. However, in order to obtain an electrical steel sheet with an insulating layer that generates an adhesive force with high productivity, it is inexpensive to focus on one product as a whole instead of using it as a product category. The material selection was made. An epoxy thermosetting resin that produces an adhesive force, and has an insulating film thickness of 2 to 6 μm. An insulating film with such a thickness does not melt by high-frequency dielectric and flow out of the iron core, and there is no problem with deterioration of characteristics due to the insulating film. Similarly, the insulating coating that produces the adhesive force applied to the surface of the electrical steel sheet may be an acrylic thermoplastic resin. The film thickness of the acrylic thermoplastic resin is 3 to 7 μm.

  The present invention relates to an electromagnetic laminated core forming method in which thin plates formed by punching a belt-shaped iron core material with a die are sequentially laminated in a die, and the laminated thin plates are integrated by heating and pressing, and an electromagnetic such as a motor or a transformer. It relates to a laminated iron core.

Sectional drawing of the small motor by Example 1 of this invention Mold sectional view of the schematic overall configuration of the mold according to Example 1 of the present invention Principle of high-frequency induction heating Coil diagram Positional relationship diagram of core blocks according to the first embodiment of the present invention Positional relationship diagram of core blocks according to the first embodiment of the present invention Positional relationship diagram of core blocks according to the first embodiment of the present invention Cross-sectional view of conventional motor structure Diagram of conventional motor core

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,36 Drive magnet 2,38 Frame 3 Rotor 4,34 Shaft 5 Armature 6,8,39,40 Sintered bearing 7 Bracket 9,33 Iron core 10,28,37 Coil 11 Electrodeposition coating film 12,41 Rectification Child 13 Terminal portion 14, 42 Brush 15 Brush holder 16 Connection terminal 17 End portion 18 Takeout port 19 Thrust plate 20 Punch 21, 31 Die 22 Electrical steel plate 23 Sheet iron core 24, 25 Heat insulation material 26 Heating coil 27 Heated material 29 Center Die 30 Protruding portion 32 Hole drilled through 35 Insulator 43 Pack 44, 49, 51 Protruding portion 45, 48, 50 Block 46, 47 Separator

Claims (4)

A magnetic steel sheet coated with an insulating coating that produces an adhesive force by heating and pressurizing the surface is punched into a sheet-shaped iron core, and a predetermined number of the obtained sheet-shaped iron cores are laminated and then heated and pressurized to be integrated. In the method of manufacturing a laminated iron core, sheet iron cores punched by the upper die and the lower die are stacked in the lower die, and a die for punching is arranged on the upper side of the lower die. Has a high frequency induction heating device for induction heating, a work holding die is arranged on the lower side of the lower mold, and heat conduction to the punching die and the work holding die is cut off above and below the high frequency induction device. A method for producing an electromagnetic laminated iron core, comprising: providing a heat insulating material and bonding and integrating a sheet-like iron core heated and laminated by a high-frequency induction heating device at a central portion of the lower mold. 2. The method for manufacturing an electromagnetic laminated core according to claim 1, wherein the protrusion is provided on the sheet-like iron core for each predetermined number of sheets so that the laminated iron core can be separated. The electromagnetic laminated iron core according to claim 1 or 2, wherein the insulating coating is formed of an epoxy thermosetting resin. The electromagnetic laminated iron core according to claim 1 or 2, wherein the insulating coating is formed from an acrylic thermoplastic resin.

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