Method for manufacturing stacked iron core and stacked iron core structure

Abstract

[Problem] To provide a method for manufacturing a stacked iron core and a stacked iron core structure, wherein an ultra-low-viscosity adhesive is applied to a side surface of a stacked body of iron core thin plates that have been punched in an outer-diameter-punching step of a progressive die device, the stacked plates are bonded by capillary action of the adhesive, and the iron core thin plates are caused to firmly adhere to each other in a reliable and stable manner by application of vibration or decompression by suction as necessary. [Solution] In the method for manufacturing the stacked iron core by a progressive die device, the ultra-low-viscosity adhesive is applied to the side surface of the stacked body of iron core thin plates that have been punched in the outer-diameter-punching step of the progressive die device, a curing agent is applied over the adhesive, and the layers of the stacked body are caused to adhere to each other, whereby the stacked iron core is manufactured.

Description

Manufacturing method of laminated iron core and laminated iron core structure

[0001] The present invention relates to a manufacturing method and laminated core structure for use in motor stators, rotors, etc., and more particularly to a manufacturing method and laminated core structure in which an ultra-low viscosity adhesive and a hardener are applied to the sides of the laminate of thin core sheets after the outer diameter punching process, which is the final process in a progressive die machine, and the thin core sheets are firmly fixed together by applying vibration, vacuuming by suction, and applying pressure to the laminate as needed. This method combines strong adhesion between the laminated sheets due to the capillary action of the ultra-low viscosity adhesive with high-speed adhesion due to the application of a hardener to the sides.

[0002] Conventionally, laminated motor cores, which are annular laminated cores formed by stacking multiple core pieces (or thin plates), have been used for motor stators and the like. Laminated cores for motors are generally manufactured using a progressive die machine from electromagnetic steel hoop material (thin steel strip). In the progressive die machine, the hoop material is sequentially punched to form pilot holes, slots, and inner teeth, continuously forming thin core plates. After punching the outer diameter, a predetermined number of thin core plates are stacked and fixed with adhesive to produce the laminated core.

[0003] Figure 1 is a schematic flow chart of the progressive process for manufacturing a laminated iron core 19, Figure 2 is a plan view showing an example of an iron core thin plate 2 after outer diameter punching, which is the final stage of the progressive process, and Figure 3 is a schematic diagram of a typical progressive die device 3.

[0004] In the first half of the punching process shown in Figure 1, the hoop material 1 is punched in the following order: pilot hole P (#1), inner diameter pilot hole d1 and small hole h for the outer groove (#2), slot portion S (#3), inner diameter d (#4), and inner diameter groove (teeth) m (#5), thereby forming the basic shape of the core sheet 2 excluding the outer diameter. During this process, the hoop material 1 is intermittently transferred within the progressive die device 3 shown in Figure 3, and punched sequentially by punches 5 to 9 attached to the upper die 4, which moves vertically. The punching process is performed by lowering a stripper plate 10 attached to the upper die 4 and bringing the hoop material 1 into contact with the upper surface 11a of the lower die 11.

[0005] Once the first half punching steps (#1 to #5) are completed, the adhesive application step (#6) is carried out. At this time, adhesive is applied to the hoop material 1 by an adhesive applicator 12 installed in the upper die 4 of the progressive die device 3. The adhesive is applied in spots to multiple locations (e.g., about six equally spaced locations) corresponding to the magnetic pole portions J and yoke portions Y between the slot portions S shown in Figure 2. The locations to which the adhesive is applied vary depending on the motor structure and manufacturing method, but if greater strength is required, the number of adhesive surfaces (points) can be increased.

[0006] After the adhesive application step (#6) is completed, the outer diameter punching step (#7) is carried out. At this time, the outer diameter punching punch 13 attached to the upper die 4 of the progressive die device 3 punches out the outer shape D to produce the iron core thin plate 2.

[0007] Once the core thin plates 2 are obtained in the outer diameter punching process (#7), the rotary stacking process (#8) is performed by the rotary drive device 17. At this time, as shown in FIG. 3 , the core thin plates 2 are stacked on top of the group of core thin plates 15 that have already been punched and stacked inside the rotary die 14. They are then sequentially pushed into the mold 16 below the rotary die 14. The rotary drive device 17 rotates the rotary die 14, which holds the group of core thin plates 15, by a predetermined angle before the newly punched core thin plates 2 are stacked on top of the group of core thin plates 15. This allows the rotational position of each core thin plate 2 to be changed during stacking, eliminating the effects of minute thickness variations that may occur in the core thin plates 2 and enabling precise control of the thickness of the product (laminated core). The rotary drive device 17 can also stack the core thin plates 2 by dropping them directly below the plate without rotating them.

[0008] Once the rotational stacking step (#8) is completed, a heating step (#9) is carried out by a heating device 18. As shown in FIG. 3, the heating device 18 is provided below the mold 16, and the group of core sheets 15 is heated as it moves downward. After heating by the heating device 18, the group of core sheets 15 is separated at the position of each measuring core sheet, and a laminated core 19 as shown in FIG. 4 is formed, which is made up of a predetermined number of core sheets 2. This laminated core 19 is placed on a belt conveyor 20 located below the lower mold 11, and is transported to the next step as appropriate.

[0009] 4 simply shows the outline of the laminated core 19, and does not correspond to the shape of the core thin plates 2 in FIG.

[0010] Japanese Patent Publication No. 2005-340691 Japanese Patent No. 5276303 Japanese Patent No. 6868719 Japanese Patent Publication No. 2009-124828 Japanese Patent Publication No. 2017-216873

[0011] Conventional methods for bonding and fixing laminated cores can be broadly divided into two types: one is performed in a progressive die apparatus, as shown in Figure 3, and the other is performed by stacking the cores on a formwork and then impregnating them with adhesive. The method of bonding in a progressive die apparatus requires the progressive die apparatus to be equipped with a dedicated adhesive introduction nozzle (discharge port) and adhesive supply device, and bonding is performed in strict synchronization with the operation of the die and press processing device. This results in a complex progressive die apparatus configuration, as well as the need for operation synchronized with the press and dedicated die maintenance, which increases operating costs. Furthermore, the method of impregnating the cores with adhesive after stacking them on a formwork requires impregnation, drying, and removal processes after stacking the cores, which also creates problems in terms of cost and maintenance.

[0012] In addition to the above-mentioned examples, two-component mixing curing techniques are also widely used in progressive die assembly bonding. In this two-component mixing method, the first component (primary component) is applied to the top surface (the upper die side of the progressive die assembly), while the second component (secondary component) is applied in multiple dots from the bottom surface. This results in a large amount of wasted adhesive, resulting in a large amount of wasted adhesive. Specifically, in this two-component mixing method, the primary component (two-component mixing) is applied to the top surface of the material sheet (such as an electromagnetic steel sheet) that is fed into the progressive die assembly, and the secondary component is applied just before pressing within the die. The advantage of this two-component mixing method is that it utilizes press pressure during pressing. Since the secondary component is applied just before the final outer diameter punching press, the primary component is not applied to areas where other forming loads are applied, so there is no hardening and no adverse effects on other processes. This allows the laminated core to be removed from the die without falling apart.

[0013] If this two-component mixing method were to be applied as a single component, the applied adhesive would drip and drag in the feed direction immediately before the final process. If the adhesive were to get on unintended areas and harden, it could cause malfunctions in moving parts or harden scrap material, resulting in processing problems. To avoid these problems, application at the final process is essential. If a slow-acting adhesive were used, depending on the product, the laminate would be ejected from the mold within a few tens of seconds and would not harden, causing the laminate to break apart and fail as a finished product. Fast-acting adhesives, such as Aron Alpha (registered trademark), cannot be used because the process itself is a pressing environment, which would interfere with release from the mold and punch.

[0014] Iron cores are laminated in a progressive die at a high SPM (Shots Per Minute). Individual core sheets (cores) are punched out with a punch and stacked together. Traditionally, crimping was the primary method to prevent loosening. In recent years, the trend toward carbon neutrality has led to a significant shift toward electrification, putting motors in the spotlight as a driving force. Naturally, demand for higher volume, higher efficiency, lighter weight, and more compact motors has grown. There is also a strong desire to reduce manufacturing costs and the amount of material used. This has led to demand for higher speed motors. Coupled with the pursuit of efficiency, the electromagnetic steel sheets used in motor cores are becoming thinner and thinner, a trend that is gaining momentum. Furthermore, new materials, such as amorphous alloys, are now being considered. As the laminates become thinner, crimping structures no longer provide the necessary holding strength, and adhesive bonding is considered a viable alternative. Furthermore, the crimping generates strain at the crimp and its surrounding area, and also accumulates strain in the surrounding area, which primarily increases iron loss and ultimately reduces motor efficiency. Bonding laminated cores is also an effective way to solve this problem.

[0015] However, adhesive bonding increases costs, requires additional equipment for application and drying, and requires synchronization of maintenance and the pressing process, resulting in costs in both raw materials and operating costs. As the need for bonding laminated cores increases, cost reduction is also a major requirement.

[0016] The present invention has been made in light of the above-mentioned circumstances, and its object is to provide a manufacturing method and laminated core structure for a laminated core in which an ultra-low viscosity adhesive is applied to the sides of a laminate of punched thin core plates in the outer diameter punching process of a progressive die device, the laminated plates are bonded together by the capillary action of the adhesive, and if necessary, vibration is applied or the pressure is reduced by suction to ensure strong, reliable bonding.

[0017] The present invention relates to a manufacturing method for manufacturing a laminated core using a progressive die device, and the above-mentioned object of the present invention can be achieved by manufacturing the laminated core by applying an ultra-low viscosity adhesive to the side surfaces of the laminate of thin core plates punched out in the outer diameter punching process of the progressive die device, applying an overlapping application of a curing agent, and bonding the laminations of the laminate; or by stacking the thin core plates punched out in the outer diameter punching process of the progressive die device in a holder, applying an ultra-low viscosity adhesive to the side surfaces of the stacked laminates and allowing it to penetrate into the interior by capillary action, applying a curing agent to the side surfaces of the laminate and fixing it, and bonding the laminations and the side surfaces of the laminate; or by applying an ultra-low viscosity adhesive to the side surfaces of the laminate of thin core plates punched out in the outer diameter punching process of the progressive die device, applying vibration to the laminate, reducing the pressure between the laminations from the inside, pressing the laminate, then applying a curing agent to the application area of ​​the ultra-low viscosity adhesive, and bonding the laminations of the laminate to manufacture the laminated core.

[0018] The present invention also relates to the structure of a laminated iron core, and the above-mentioned object of the present invention is achieved by bonding the layers in a laminate of thin iron core plates with an ultra-low viscosity adhesive, and by bonding the sides of the laminate with a curing agent.

[0019] According to the manufacturing method of the laminated core of the present invention, in the final outer diameter punching process of the progressive die device, an ultra-low viscosity adhesive is applied to the side of the laminate of punched core thin plates, and the laminations are bonded together using the capillary action of the ultra-low viscosity adhesive, so that the structure of the progressive die device can be simplified to manufacture laminated cores. Furthermore, in addition to the capillary action of the ultra-low viscosity adhesive itself, the application of vibration and decompression by suction can further promote capillary action, resulting in stronger bonding.

[0020] Furthermore, since a fast-adhesive curing agent is applied to the side surfaces of the laminate, the laminate can be stabilized and bonded reliably.

[0021] Naturally, the amount of adhesive used can be reduced by eliminating the need to apply the primary agent (adhesive) to the entire surface. Conventionally, although the primary agent does not harden, it remains inside the mold, and special cleaning of the entire mold is required for periodic removal or when disassembling the mold for maintenance. However, with the present invention, such maintenance and cleaning are not necessary.

[0022] Furthermore, according to the present invention, the amount and type of adhesive used (two-component → one-component) can be reduced, which reduces costs and makes management easier.

[0023] FIG. 1 is a schematic flow chart showing an example of a progressive process. FIG. 2 is a plan view of the iron core thin plate after punching. FIG. 3 is a schematic configuration diagram of a progressive die device. FIG. 4 is a perspective view showing an example of a laminated iron core. FIG. 5 is a schematic perspective view showing an example of the operating principle of the present invention. FIG. 6 is a flowchart showing an example of the operation of the present invention. FIG. 7 is a schematic perspective view for explaining an example of the operation of the present invention. FIG. 8 is a schematic cross-sectional view for explaining infiltration (without vibration) of an adhesive example of the present invention. FIG. 9 is a schematic cross-sectional view and a cross-sectional perspective view when suction (decompression) is performed of an adhesive example of the present invention. FIG. 10 is a schematic cross-sectional view for explaining infiltration (with vibration) of an adhesive example of the present invention. FIG. 11 is a perspective view showing another example of a holder.

[0024] The present invention relates to a manufacturing method for a laminated core using a progressive die machine. This method involves applying an ultra-low viscosity adhesive to the side of a laminate of thin core plates punched in the outer diameter punching process of the progressive die machine, and then applying a curing agent in an overlapping manner to firmly bond the laminated layers together. The ultra-low viscosity adhesive used in this invention has a viscosity equivalent to or lower than that of water. When applied to the side of the laminate, it penetrates narrow spaces between the laminations (between the top and bottom surfaces) by capillary action. This penetration of the adhesive into the interior of the laminations ensures reliable bonding and strong adhesion between the laminations. The capillary action is further promoted by the application of vibration and reduced pressure by suction. Furthermore, the overlapping application of the curing agent to the side promotes internal penetration and hardening, resulting in stronger and more stable adhesion, since the curing agent hardens quickly and maintains the shape of the laminate.

[0025] An example of an ultra-low viscosity adhesive that can be used is the instant adhesive "Aron α (registered trademark) 101 / 4000." Although the initial hardening of the curing agent is fast, taking only a few tens of seconds, it takes several hours for the adhesive to fully harden. Therefore, it is not necessary to apply the curing agent immediately after applying the ultra-low viscosity adhesive. Therefore, the curing agent only needs to be applied within the time frame expected for this process. For example, "aa.Setter" can be used as the curing agent.

[0026] FIG. 5 schematically illustrates the manufacturing principle of the present invention. The core laminations 100 punched in the outer diameter punching process are removed and stacked sequentially in a cylindrical holder, forming a laminate 120 in which a predetermined number (or height) of core laminations 100 are stacked. Ultra-low viscosity adhesive 110 is then applied vertically to two opposing sides of the laminate 120, from top to bottom or vice versa, and a lid 150 is placed on top and pressed. A curing agent 111 is then applied over the ultra-low viscosity adhesive 110. The ultra-low viscosity adhesive 110 applied to the sides of the laminate 120 has an ultra-low viscosity, and gradually penetrates inward between the laminations by capillary action, with the penetration accelerated by the pressing action. Furthermore, the application of the curing agent 111 rapidly hardens the sides of the laminate 120, thereby bonding them together, and the adhesive that has penetrated into the interior gradually bonds the laminations together. This makes it possible to obtain a high-quality laminated core that is firmly and stably fixed.

[0027] In FIG. 5, the ultra-low viscosity adhesive 110 and the curing agent 111 are applied to a pair of opposing locations, but they may be applied to two or more pairs of opposing locations, or may be applied to three T-shaped locations as described below.

[0028] FIG. 6 is a flowchart showing an example of a manufacturing method for a laminated core according to the present invention. In the outer diameter punching process using a progressive die, outer diameter punching is performed (step S1). The punched core sheets 100 are then successively dropped and stacked in a holder 140 (step S2) as shown in FIG. 7. The side of the holder 140 has two opposing elongated vertical openings 140A and 140B for applying adhesive 110 and hardener 111. When a predetermined number of core sheets 100 are stacked in the holder 140 (or when a predetermined height H1 is reached) (step S3), ultra-low viscosity adhesive 110 is applied to the side of the stacked volume 120 through the openings 140A and 140B (step S4), as shown in FIG. 7, and then allowed to penetrate between the layers by capillary action (step S5). The cross-sectional view of FIG. 8 shows the penetration of ultra-low viscosity adhesive 110 between the layers by capillary action when applied to the side of the stacked volume 120.

[0029] Once the ultra-low viscosity adhesive 110 has completely penetrated between the layers (step S5), vibration is applied via the holder 140 using a vibrator or the like (step S6). This is shown in the cross-sectional view of Figure 9, and the addition of vibration further promotes penetration. The pressure inside the holder 140 is then reduced by suction using a pump or the like (step S7), and then the lid 150 is placed on top of the holder 140 and presses against the laminate 120 from above (step S8). This pressure enhances the adhesive action between the layers.

[0030] 7, curing agent 111 is applied onto the applied portion of ultra-low viscosity adhesive 110 through openings 140A and 140B (step S9), and laminated body 120 is fixed by the hardening action of ultra-low viscosity adhesive 110 and the rapid hardening of curing agent 111 to produce a laminated core (step S10), which is then transported by a belt conveyor or the like as appropriate for use (step S11). By applying ultra-low viscosity adhesive 110 and curing agent 111 to the side surfaces of laminated body 120 in this manner, a firmly fixed laminated core can be produced.

[0031] In the above example, vibration is applied and then suction is performed to reduce the pressure, but the reverse may be true, or vibration and suction may be performed simultaneously.

[0032] When reducing the pressure by suction from the inside using a pump or the like, a holder 160 and a lid 161 as shown in Figures 10(A) and 10(B) are used. That is, the holder 160 has almost the same structure as the holder 140 described above, but does not have an opening on the side, and a cylindrical suction port 162 is provided in the center of the lid 161. The suction port 162 is connected to a pump or the like, and by suctioning the inside, a force acts from the outer surface of the laminate 120 toward the inside, further promoting the penetration of the ultra-low viscosity adhesive 110. In the example of Figure 10, a vibrator 130 is attached, so that vibration can also be applied.

[0033] Applying vibration to the laminated material creates a pumping action in which the volume changes based on the expansion and contraction of the gaps, thereby increasing the penetration of adhesive into the interior. Furthermore, reducing the pressure inside using a structure such as that shown in Figure 10 further promotes the penetration of adhesive from the outer surface. However, applying vibration (step S6) and reducing the pressure by suction (step S7) are not essential steps in the manufacture of a laminated core, and can be omitted.

[0034] FIG. 11 shows the height H2 of the laminate 120 compared to the specified height H1 of the laminate 120, and by making H2 > H1, it is possible to encourage the gaps to expand further inward, thereby allowing for deeper penetration.

[0035] 12 shows a split T-shaped holder 141 with vertical openings 141A to 141C formed in a T-shape. When using this holder 141, ultra-low viscosity adhesive 110 and hardener 111 are applied to three locations on the side of the laminate through openings 141A to 141C to manufacture the laminated core.

[0036] In the above example, an ultra-low viscosity adhesive is used as the adhesive, and a curing agent is applied in layers. However, if a low-viscosity photo / anaerobic curing adhesive that has both anaerobic and photo-curing properties is used, the side surfaces can be cured by light irradiation without using a curing agent.

[0037] Furthermore, although the laminated core has been described above as having a circular ring shape, it can also be applied to a disk or a rectangle. The material has been described as being an electromagnetic steel sheet, but it can also be applied to an amorphous material, and any soft magnetic material will do.

[0038] REFERENCE SIGNS LIST 1 hoop material 2 iron core thin plate 3 progressive die device 4 upper die 5 to 9 punch 10 stripper plate 11 lower die 12 adhesive application device 13 outer diameter punching punch 14 rotary die 15 iron core thin plate group 16 mold 17 rotary drive device 18 heating device 19 laminated iron core 20 belt conveyor 100 iron core thin plate 110 ultra-low viscosity adhesive 111 hardener 120 laminated body 130 vibrator 140, 141, 160 holder 140A, 140B opening 150, 161 lid

Claims

1. A manufacturing method for manufacturing a laminated iron core using a progressive die device, characterized in that an ultra-low viscosity adhesive is applied to the side of the laminate of thin iron core plates punched out in the outer diameter punching process of the progressive die device, and a hardener is also applied, and the laminated layers of the laminate are bonded together to manufacture the laminated iron core.

2. The method for manufacturing a laminated core according to claim 1, wherein vibration is applied after the application of the ultra-low viscosity adhesive.

3. A method for manufacturing a laminated core according to claim 1 or 2, wherein the pressure between the laminations is reduced from the inside after the application of the ultra-low viscosity adhesive.

4. A method for manufacturing a laminated core according to claim 3, wherein the laminate is pressed after the application of the ultra-low viscosity adhesive.

5. A manufacturing method for manufacturing a laminated iron core using a progressive die device, characterized in that the iron core thin plates punched out in the outer diameter punching process of the progressive die device are stacked in a holder, an ultra-low viscosity adhesive is applied to the sides of the stacked laminates and allowed to penetrate into the interior by capillary action, a hardener is applied to the sides of the stacks to fix them, and the laminated iron core is manufactured by bonding the layers and sides of the stacks.

6. A method for manufacturing a laminated core according to claim 5, wherein the material of said laminated core is a soft magnetic material.

7. A manufacturing method for manufacturing a laminated iron core using a progressive die device, characterized in that an ultra-low viscosity adhesive is applied to the side of a laminate of thin iron core plates punched out in the outer diameter punching process of the progressive die device, vibration is applied to the laminate, the space between the laminates is reduced from the inside, the laminate is pressed, and then a hardener is applied to the applied area of ​​the ultra-low viscosity adhesive, and the laminates of the laminate are bonded together to manufacture the laminated iron core.

8. The method for manufacturing a laminated core according to claim 7, wherein the material of said laminated core is a soft magnetic material.

9. A laminated core structure characterized in that the laminations in a laminate of thin iron core plates are bonded together with an ultra-low viscosity adhesive, and the sides of the laminate are fixed with a hardener.

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