Method and apparatus for manufacturing laminated steel sheet

Abstract

[Problem] To provide a method and an apparatus for manufacturing a laminated steel sheet suitable for manufacturing a laminated steel sheet at high speed. [Solution] Provided is a manufacturing method for a laminated iron core in which an iron core is punched from a belt-shaped thin steel sheet 10 that is intermittently conveyed and the punched iron cores are bonded and stacked sequentially. In this method, an adhesive discharge nozzle 24 is provided for injecting an adhesive from a lower surface of a punch 22 for outer shape punching disposed in an upper mold, the punch 22 is lowered into a die hole formed in a die plate 32 held by a lower mold 30 to punch an iron core from the belt-shaped thin steel sheet 10, and then the punch is raised to be separated from the die hole, and at a timing when a discharge space surrounded by members including the lower surface of the punch 22 and the punched iron core communicates with the atmosphere, the adhesive is injected from the adhesive discharge nozzle 24 to the upper surface of the punched iron core.

Description

Manufacturing method and manufacturing device for laminated steel sheet

[0001] The present invention relates to a method and an apparatus for manufacturing laminated steel sheets (laminated iron cores) used in motors and the like.

[0002] A conventional method for producing laminated cores for use in the stators and rotors of rotating electrical machines involves using a progressive die including a punching die (die set) at multiple locations to punch out cores from an intermittently transported strip-shaped thin steel sheet, stacking the punched cores sequentially in the die, and bonding them together with an adhesive to obtain a laminated core.

[0003] For example, in Patent Document 1, an adhesive applicator is provided facing the underside of the thin steel plate on the upstream side (forward) before the outer shape is punched out by the punch, and adhesive is sprayed from below upward.

[0004] Furthermore, as shown in FIG. 2D of Patent Document 2, a technique is known in which adhesive is dripped onto the thin steel sheet from the lower end of an adhesive discharge means disposed in the outline punch while the stripper plate is pressing the thin steel sheet against the lower die and the lower surface of the outline punch is spaced apart from the upper surface of the thin steel sheet.

[0005] More specifically, an airtight space is formed by the stripper plate, the lower die, the previously punched iron core, and the underside of the outline punch, and adhesive is dripped onto the thin steel plate from the lower end of the adhesive discharge means.

[0006] JP 2001-25218 A Japanese Patent No. 6618203 A

[0007] However, in the method disclosed in Patent Document 1, in order to prevent the discharged adhesive from adhering to the underside of the thin steel sheet and the die surface, a recessed groove is formed in the upper surface of the die corresponding to the outlet of the adhesive applicator. However, because the adhesive application position and the outline punching position are separate, it takes time for feeding the thin steel sheet, and it is difficult to eliminate the possibility of the adhesive adhering to the die surface.

[0008] On the other hand, in the method of Patent Document 2, the adhesive is "dripped" onto the thin steel plate, which takes a long time to "drip" and slows down the processing speed for applying the adhesive onto the thin steel plate, and is therefore considered to be unsuitable for high-speed production of laminated steel plates.

[0009] Therefore, a main object of the present invention is to provide a method and an apparatus for manufacturing laminated steel sheets that are suitable for manufacturing laminated steel sheets at high speeds.

[0010] The above-mentioned problems are solved in the following embodiments: (First Aspect) A method for manufacturing a laminated core in which cores are punched out from an intermittently conveyed strip-shaped thin steel sheet, glued, and laminated in order, the method comprising the steps of: providing an adhesive discharge nozzle that sprays adhesive from the underside of a contour punch arranged in an upper die; the punch descends into a die hole formed in a die held in a lower die to punch out the iron cores from the strip-shaped thin steel sheet; and then the punch rises and separates from the die hole, and adhesive is sprayed from the adhesive discharge nozzle onto the upper surface of the punched iron core at the point when the discharge space surrounded by the underside of the punch and the die members containing the punched iron cores is communicated with the atmosphere.

[0011] (Second aspect) A manufacturing device for laminated iron cores, in which iron cores are punched out from intermittently transported strip-shaped thin steel plate, glued, and stacked in sequence, comprising: an adhesive discharge nozzle that sprays adhesive from the underside of a contour punch arranged in an upper mold; means for lowering the punch into a die hole formed in a die held in a lower mold to punch out iron cores from the strip-shaped thin steel plate; and adhesive spray means that sprays adhesive from the adhesive discharge nozzle onto the top surface of the punched iron core when the punch rises and moves away from the die hole and a discharge space surrounded by the underside of the punch and the die member containing the punched iron core communicates with the atmosphere.

[0012] According to the present invention, it is possible to provide a method and an apparatus for manufacturing laminated steel sheets that are suitable for manufacturing laminated steel sheets (laminated iron cores) at high speed.

[0013] 1 is a schematic diagram of a manufacturing apparatus according to an embodiment in a state before outline punching; FIG. 1 is a schematic diagram of a state in which the position of a thin steel plate is regulated by a stripper plate; FIG. 1 is a schematic diagram of a state in which outline punching is performed; FIG. 2 is a schematic diagram of a state in which an adhesive is sprayed; FIG. 3 is a schematic diagram of an example of the arrangement of a receiving device; FIG. 4 is a schematic diagram of a state in which a punching hand core is held by a receiving device; FIG. 5 is a schematic diagram of a state in which a laminated iron core is carried out; FIG. 6 is an explanatory diagram of the timing of adhesive discharge and spraying; FIG. 7 is an explanatory diagram of the relationship between the punch for outline punching and the iron core; FIG. 8 is a schematic diagram of an example of an accommodation hole for an adhesive discharge nozzle; FIG. 9 is a schematic diagram of an example of up and down movement of the adhesive discharge nozzle; FIG. 10 is a schematic diagram of an example of outward discharge and spraying from the adhesive discharge nozzle; FIG. 11 is a schematic diagram of an example of a laminated iron core being carried out; FIG. 12 is a schematic diagram of an example of an adhesive application area; FIG. 13 is a schematic diagram of an example of an adhesive application area and the underside of a punch for outline punching; (A) is an example of an adhesive application area, and (B) is an explanatory diagram showing the relationship between the example of an adhesive application area and the position of the adhesive discharge nozzle after rotation of the laminated iron core; FIG. 18 is a schematic diagram of an example of the arrangement of a resin sleeve (an enlarged view of a main part of FIG. 17 ).

[0014] Next, embodiments of the present invention will be described in detail below with reference to the drawings.

[0015] (Outline of Manufacturing Apparatus) Figure 1 shows the main parts of the manufacturing apparatus, illustrating the process of punching the outline of an iron core from an intermittently conveyed strip-shaped thin steel sheet (e.g., silicon steel sheet) 10 (the punching of holes in the iron core prior to outline punching is not shown in Figure 1), and also shows the manufacturing equipment for laminated iron cores in which sheets are glued and sequentially laminated, and shows the stages of punching the outline of the iron core from the thin steel sheet 10 and applying adhesive at the same position. In the embodiment, because the outline punching of the iron core and the application of adhesive are carried out at the same position (process), unlike in Patent Document 1, there is no need for intermittent conveyance from the adhesive application station to the outline punching station of the iron core, making it possible to manufacture at high speed.

[0016] In the manufacturing apparatus of the embodiment, an adhesive discharge nozzle 24 is provided inside a punch 22 for punching an outline, which is placed in an upper die 20 that moves up and down, and the adhesive discharge nozzle 24 faces an opening on the lower surface 22a of the punch 22. With the adhesive discharge nozzle 24 facing the opening on the lower surface 22a of the punch 22 for punching an outline, the punch 22 descends into a die hole 32a of a die plate 32 held by a fixed lower die 30, and punches out the outline of the iron core from the strip-shaped thin steel sheet 10.

[0017] A stripper plate 26 is provided below the upper die 20. When a strip-shaped thin steel sheet 10 is transported, before the punch 22 punches out the thin steel sheet 10, the stripper plate 26 is lowered by a biasing member 27 such as a spring, pressing the thin steel sheet 10 against the die plate 32 and regulating the vertical position of the thin steel sheet 10.

[0018] The adhesive discharge nozzle 24 is provided such that, for example, its lower end is located above the underside of the outline punch 22, and the lower end of the adhesive discharge nozzle 24 faces the opening in the underside of the outline punch 22. In the illustrated state, the adhesive discharge nozzle 24 itself is provided, for example, to vertically penetrate the outline punch 22, but the arrangement of the adhesive discharge nozzle 24 and the flow path of the adhesive can be selected as appropriate.

[0019] The embodiment includes an adhesive application device 25, which is composed of an adhesive supply mechanism equipped with a syringe or the like for storing adhesive, an adhesive discharge nozzle 24 provided within the punch 22, and an adhesive spray mechanism including an on-off valve for spraying the adhesive. The adhesive discharge nozzle 24 in the embodiment sprays adhesive liquid downward onto the upper surface of the thin steel sheet 10 in a non-contact manner. For example, a known jet-type dispenser can be selected as the adhesive discharge nozzle 24. The number of adhesive discharge nozzles 24 to be installed is selected to be one, two, or more, depending on the number of bonding locations required, for example, on a circle around the vertical axis of the punch 22.

[0020] The adhesive spraying mechanism for spraying the adhesive includes, for example, a piezoelectric valve actuator, and the timing of starting and stopping the spraying is determined based on a command signal from the control device 50, and the adhesive is pressurized and sprayed, for example, as fine droplets.

[0021] Next, an example of the manufacturing process will be described with reference to Figures 1 to 7. As shown in Figure 1, when a strip-shaped thin steel sheet 10 is transported to the punching station, it is placed above the upper surface of a die plate 32 by a lifter 33 (the die is not shown).

[0022] 2, before the punch 22 punches out the thin steel sheet 10, the stripper plate 26 descends to press the thin steel sheet 10 against the die plate 32, thereby restricting the vertical position of the thin steel sheet 10. In this state, the lower surface of the punch 22 is spaced apart from the upper surface of the thin steel sheet 10, and an enclosed space is formed between the side surface of the through hole in the stripper plate 26 and the thin steel sheet 10. This enclosed space is indicated by the symbol CS. In this embodiment, the tip of the adhesive discharge nozzle 24 is positioned above the lower surface of the punch 22 and faces the enclosed space CS.

[0023] Thereafter, as shown in FIG. 3, with the adhesive discharge nozzle 24 facing the opening on the underside of the punch 22 for punching the outer shape, the punch 22 is lowered into the die hole 32a formed in the die plate 32 held by the lower mold 30, and the outer shape of the iron core is punched out of the thin steel plate 10.

[0024] Next, as shown in FIG. 4, the punch 22 rises and moves away from the die hole 32 a, the upper mold 20 rises, and the stripper plate 26 also rises. As a result, the discharge space surrounded by the underside of the punch 22 and the member including the punched iron core communicates with the atmosphere, that is, when a communication space HS is formed, adhesive is sprayed downward from the adhesive discharge nozzle 24 that passes through the inside of the punch 22 and onto the top surface of the punched iron core.

[0025] Thereafter, the punched core is rotated by a predetermined angle (for example, 90°) as shown in Fig. 5, and at the same time, the thin steel sheet 10 is conveyed downstream. Next, the outline punching is performed at the outline punching station as shown in Fig. 6, followed by adhesive injection as shown in Fig. 4.

[0026] During the outline punching process shown in FIG. 6, the bottom surface of the punch is a flat surface without adhesive discharge nozzles 24, which can crush the adhesive between the previously applied iron cores. This spreads the adhesive evenly, stabilizing the adhesive strength.

[0027] The process shown in FIGS. 1 to 5 is regarded as one unit, and a predetermined number of cores are subjected to punching and adhesive application.

[0028] The punched cores are received by a receiving device 40 shown in Fig. 7, for example, and can be stacked one after the other. The receiving device 40 has a back pressure plate portion 40a at its top and a holding portion 40b that elastically holds the back pressure plate portion 40a. The receiving device 40 is preferably rotatable about a vertical axis and can be retracted below the lower die 30 so that a predetermined number of laminated cores M (see Fig. 7) can be discharged to the destination.

[0029] That is, the die 32A and squeeze ring 41 support the punched core as shown in Fig. 6, and then support the next punched core while rotated by a predetermined angle around the vertical axis as shown in Fig. 5. The cores are received and rotated one by one in sequence, and the receiving device 40 holds the laminated cores in a stacked state. When a predetermined number of cores have been stacked, the receiving device 40 retreats below the lower die 30 as shown in Fig. 7, and the laminated cores M (see Fig. 7) with the predetermined number of cores stacked are discharged to their destination.

[0030] As described above, for example, in Patent Document 1, an adhesive applicator is provided facing the underside of the thin steel sheet on the upstream side (forward) prior to punching the outer shape with a punch, and in a configuration in which adhesive is dispensed from below upward, there is a risk that the dispensed adhesive will adhere to the underside of the thin steel sheet and then to the die or die plate surface. Furthermore, if a lifter is provided, there is a risk that the adhesive will adhere to the lifter and become impossible to remove, necessitating cleaning.

[0031] In contrast, as shown in the embodiment, the punch 22 for punching the outer shape moves down to punch out the core from the strip-shaped thin steel plate, and adhesive is sprayed onto the upper surface of the punched core at the same position as this punching, so it is possible to prevent the adhesive from adhering to the die or die plate surface, lifters, etc. Furthermore, the flat surface without a nozzle on the lower surface 22a of the punch 22 for punching the outer shape presses (applies pressure to) the punched core onto the previously punched and rotated core, so that the adhesive previously applied to the punched core is spread over the punched core, forming a wide bonding surface area, which also brings about the advantage of increasing the adhesive strength.

[0032] In this embodiment, the adhesive is sprayed onto the top surface of the punched iron core, rather than being "dripped" as in Patent Document 2. The method of Patent Document 2 requires a certain amount of time for the "dripping" to be completed, making it unsuitable for high-speed application of adhesive.

[0033] In addition, in the embodiment of Patent Document 2, adhesive is dripped onto the thin steel sheet from the lower end of the adhesive discharge means while the stripper plate presses the thin steel sheet against the lower die and the lower surface of the outline punch is separated from the upper surface of the thin steel sheet, i.e., while forming an enclosed space surrounded by these. The reason for this is unclear, but it is speculated that it is due to the need to apply the adhesive as directly below as possible to avoid the influence of ventilation in the factory when "dripping" the adhesive. According to the embodiment of the present invention, there is a possibility that processing oil applied in advance to prevent die wear may adhere to the surface of the iron core. However, even if processing oil is adhered to the surface of the iron core, there is an advantage that the processing oil can be pushed aside by the spray and the adhesive can be applied.

[0034] According to this embodiment, when punch 22 rises and separates from die hole 32a, and the discharge space surrounded by undersurface 22a of punch 22 and the member including the punched iron core communicates with the atmosphere, that is, when a communicating space HS is formed as shown in Fig. 4, adhesive is sprayed from adhesive discharge nozzle 24 onto the upper surface of the punched iron core. Since the adhesive is sprayed when the communicating space HS shown in Fig. 4 is formed from the sealed space CS shown in Fig. 2, the spray direction of the adhesive is uniformly determined and stable.

[0035] For example, the time when the punch 22 is connected to the atmosphere before the top dead center shown in FIG. 4 can be linked to the press angle signal, and adhesive can be sprayed from the adhesive discharge nozzle 24 onto the top surface of the punched core based on the press angle signal. That is, for example, in a press machine having the crank angle and ram stroke relationship shown in FIG. 8, when the material transfer is completed, the material is pressed down by the stripper plate 26, and punched out as it reaches the bottom dead center of the press. After that, the stripper plate 26 rises, and once the communication space HS is formed, adhesive is sprayed immediately. Material transfer then begins. Linking the timing to the press angle signal allows for accurate and reliable control. Furthermore, since the number of punches can be detected, it is possible to determine whether adhesive spraying is required for each laminated core.

[0036] For example, as shown in Figure 9, an embodiment is provided in which the adhesive discharge nozzle 24 is positioned such that its lower end is above the lower surface 22a of the punch 22 for punching the outer shape, facing the opening in the lower surface 22a of the punch 22 for punching the outer shape. On the other hand, in Japanese Patent No. 7138899, as shown in Figure 18 thereof, the adhesive discharge nozzle is provided to protrude downward from the lower surface of the punch for punching the outer shape. In this embodiment, there is a risk that the lower end of the adhesive discharge nozzle may come into contact with the iron core material, causing a dent and damaging the adhesive discharge nozzle. According to an embodiment in which the lower end of the adhesive discharge nozzle 24 is provided such that it faces the opening in the lower surface 22a of the punch 22 for punching the outer shape, this risk can be avoided.

[0037] 10, for example, a configuration is provided in which the lower end of the accommodation hole 22b of the punch 22 provided with the adhesive discharge nozzle 24 has an enlarged surface 22c that expands toward the lower surface 22a of the punch 22. This configuration is highly effective in preventing adhesion to the opening of the punch 22 used for outer shape punching.

[0038] 11, the adhesive discharge nozzle 24 may be provided so that its vertical position can be adjusted relative to the punch 22. For example, the vertical movement distance is indicated by the symbol S. After a certain number of shots, the punch and die may need to be polished, and the distance between the adhesive discharge nozzle 24 and the target surface can be adjusted to achieve an appropriate adhesive spray state.

[0039] 12, for example, a configuration is also provided in which the adhesive is ejected from the adhesive ejection nozzle 24 in the direction toward the outer periphery of the laminated core. In order to maintain the strength of the punch 22, the adhesive ejection nozzle 24 is positioned a predetermined distance inward from the outer periphery, which solves the problem of applying adhesive to the outer peripheral edge of the core, which is difficult to do.

[0040] As explained above with reference to Fig. 7, the punched cores are received by, for example, a receiving device 40 shown in Fig. 7 and can be stacked one after the other. During this receiving and stacking process, it is desirable that the thin cores 10a be flat and not warped. If the cores are warped and not flat, when the adhesive applied to the top surface of the previously punched core is pressed by the punch 22 to punch the next core, the adhesive will not be able to spread sufficiently around the periphery, or it will flow in an unintended direction, making it difficult to obtain the required adhesive strength between the cores.

[0041] Therefore, it is desirable that the receiving device 40, also shown in FIG. 13 , has a holding portion 40b that elastically holds the upper back pressure plate portion 40a, and that the laminated core be pressed between the punch 22 and the back pressure plate portion 40. It is also desirable to provide a squeeze ring 41 that is continuous with the die hole 32a of the die plate 32, and to press the outer periphery of the laminated core toward the center. One configuration for pressing the outer periphery of the laminated core toward the center is to make the inner diameter of the squeeze ring 41 approximately the same as or smaller than the outer diameter of the punched core. Another example of a configuration for pressing the outer periphery of the laminated core toward the center is to divide the squeeze ring 41 circumferentially and provide biasing means (such as a spring or movable means) 41a that biases each divided squeeze ring 41 toward the center.

[0042] In this case, it is more preferable that the back pressure by the back pressure plate portion 40a and / or the lateral pressure (the biasing force toward the center) of the squeeze ring 41 be adjustable.

[0043] In this embodiment, adhesive is applied by spraying onto the top surface of the punched iron core 10a at a distance from the adhesive discharge nozzle 24. Therefore, when the adhesive applied to the top surface of the previously punched iron core is pressed by the punch 22 to punch the next iron core, it is desirable to press it on a flat surface of the punch that does not have a nozzle opening so that the adhesive can be sufficiently spread (expanded) around the periphery.

[0044] However, even if punch 22 is pressed directly against the top surface of laminated core 10a, as shown in Figure 14, the position of core 10a facing adhesive discharge nozzle 24 has accommodation hole 22b or enlarged surface 22c open, and the flat surface of bottom surface 22a of punch 22 is not in contact with the top surface of core 10a. Furthermore, this embodiment does not discharge adhesive in a state where the adhesive discharge nozzle is positioned to protrude below the bottom surface of the punch used for punching the outline, as in Patent No. 7138899.

[0045] Therefore, when the adhesive applied to the top surface of the previously punched core is pressed by punch 22 to punch the subsequent core, it is desirable that die 32A, squeeze ring 41, etc. rotate as shown in Figure 15 so that the adhesive applied to the top surface of the previously punched core is not located below adhesive discharge nozzle 24, and so that the flat surface on the bottom of punch 22 abuts against the area of ​​the core to which the previously applied adhesive was applied, allowing the adhesive to be sufficiently spread (expanded) around. Note that the rotation of die 32A, squeeze ring 41, etc. is timed after the punch has come out of the die to avoid interference.

[0046] As an example of such a technique, for example, as shown in FIG. 5, a rotary lamination mechanism of an appropriate configuration known to those skilled in the art is used, which rotates the laminated core M around its axis using a die 32A and a squeeze ring 41. As shown in FIG. 15, it is desirable to abut the flat surface of the lower surface 22a of the punch 22 against the area of ​​the iron core 10a where the adhesive was previously applied, thereby sufficiently spreading (expanding) the adhesive around the periphery.

[0047] As a specific example, as shown in Figure 16 (A), when adhesive Ad is applied to an iron core 10a using five adhesive discharge nozzles 24 arranged at an opening angle of 72 degrees from the center of the punch 22, if the laminated iron core M is rotated, for example, 180 degrees around its axis by a receiving device 40 using a rotational stacking mechanism, as shown in Figure 16 (B), the application portion of the previously applied adhesive Ad will be positioned opposite the flat surface of the underside 22a of the punch 22 that does not have the adhesive discharge nozzles 24.As a result, the underside 22a of the punch 22 will abut against the application portion of the previously applied adhesive Ad on the iron core 10a, and the adhesive can be sufficiently spread (expanded) around.

[0048] In this way, it is desirable to have a rotation process in which adhesive is sprayed from an adhesive discharge nozzle onto the top surface of the punched iron core, and then the laminated iron core is rotated a predetermined angle around the axis by a rotary stacking mechanism, and after the laminated iron core is rotated around the axis by the rotation process, the lower surface of the punch applies pressure to the thin steel plate of the laminated iron core during the next outer shape punching.

[0049] By rotating the laminated core around the axis during the rotation process, the advantage is realized that the adhesive can be sufficiently spread (expanded) around the periphery, provided that, in a plan view of the core, at least one of the multiple adhesive injection positions on the top surface of the previously punched-out iron core and the multiple pressure positions on the top surface of the iron core during the next outer shape punching is in a different relationship.

[0050] In the above embodiment, prior to the step of discharging the adhesive from above to below the thin steel plate 10, a step of applying the adhesive from below to above the thin steel plate 10 may be performed, as has been conventionally widely done. This application of the adhesive from below to above the thin steel plate 10 may be performed by spraying the adhesive, in addition to applying the adhesive by coating.

[0051] Furthermore, in this embodiment, the adhesive discharge nozzle 24 is disposed within the punch 22 for outer shape punching. However, a short nozzle may be disposed between the adhesive applicator 25 of the upper die 20 and the punch 22 for outer shape punching, or just before the punch 22. In this case, the adhesive becomes droplets and passes through the punch's accommodation hole (through-hole) before being sprayed from the underside of the punch. As shown in FIG. 17 , the adhesive discharge nozzle 24 is disposed within the adhesive applicator 25, and a resin sleeve 24S forms an adhesive passage through the punch 22. Furthermore, when applying adhesive from below to above the thin steel sheet 10, if there is at least one visible difference between the adhesive application area and the adhesive application area from the adhesive discharge nozzle from above to below the thin steel sheet 10, the adhesive can be sufficiently spread (expanded) around the periphery. In this embodiment, it is not necessary to rotate the laminated core M by a predetermined angle around the axis using a rotary lamination mechanism. In the embodiment (Fig. 1, etc.), the punch 22 for punching the outer shape protrudes downward from the inside of the upper die 20, but it may also protrude downward from the underside of the upper die. A clearance may be provided between the hole in the punch and the nozzle. Furthermore, the adhesive discharge nozzle 24 is long and passes through the hole in the punch 22 for punching the outer shape, but it may be any length and may be short.

[0052] Specifically, the adhesive applicator 25 can be arranged on the upper die 20, for example, in the form shown in Figure 17. The upper die 20 holds the adhesive applicator 25 and also holds the outline punch 22 using a punch fixing member 21. The adhesive applicator 25 has a discharge nozzle 24 and sprays adhesive. The sprayed adhesive passes through a resin sleeve 24S that penetrates the outline punch 22 and an opening on the bottom surface of the punch, and lands on the top surface of the punched iron core held in the lower die 30. The adhesive applicator 25, discharge nozzle 24, resin sleeve 24S, and punch 22 are arranged so that they can rise and fall together with the upper die 20.

[0053] Since vibrations and impacts act on the upper die 20 and the punch 22 for punching the outer shape during the pressing operation, vibrations and impacts also act on the adhesive applicator 25 housed in the upper die 20. Therefore, it is desirable that the adhesive applicator 25 be provided within the space of the upper die 20 via elastic impact absorbing members 60, 60 above and below it.

[0054] 17, an adhesive applicator 25 is placed in a recess 20a formed in an upper mold 20, with a lower impact absorbing member 60 interposed between its lower surface and the lower surface of the recess 20a, and an upper impact absorbing member 60 interposed between its upper surface and a fixing member 20b covering the recess 20a, so that the adhesive applicator 25 is placed. A plan view of the absorbing member 60 is shown in FIG.

[0055] The lower impact absorbing member 60 has flow holes 60a formed at positions corresponding to the resin sleeves 24S of the adhesive discharge nozzles 24 so as to enable fluid connection with the adhesive application device 25 that supplies adhesive into the resin sleeves 24S of the adhesive discharge nozzles 24.

[0056] The material of the shock absorbing member 60 is preferably an elastic material for absorbing vibrations and / or shocks, and is particularly preferably a rubber material with a Shore A hardness of 25 to 50. The Shore A hardness can be measured in an environment of 23°C in accordance with the description of JIS K6253-3:2012. The shock absorbing member 60 can be fixed to the upper mold 20 or the adhesive application device 25 by appropriate means.

[0057] As described above, vibrations and shocks act on the adhesive applicator 25, and the vibrations and shocks can be absorbed by the upper shock absorbing member 60 and the lower shock absorbing member 60. In the embodiment, since the adhesive applicator 25 has a cylindrical shape, the position restricting member 70 can be fixed to the upper mold 20 using fixing members such as fixing bolts 70c in the positioning holes 70b or positioning pins 70d in the positioning holes 70b around the position restricting member 70. A plan view of the position restricting member 70 is shown in Figure 19.

[0058] The adhesive application device 25 is divided into two parts, an upper part and an lower part, and is fixed to the upper mold 20 by sandwiching a position regulating member 70. The position regulating member 70 can be formed with a wiring relief hole 70e, a weight reduction hole 70f, and the like.

[0059] Although the type of adhesive is not necessarily limited, it is desirable to use an anaerobic adhesive in order to quickly secure the laminated thin steel sheets. However, anaerobic adhesives harden in a short time once they are attached to metal. If the anaerobic adhesive sprayed from the adhesive discharge nozzle 24 of the adhesive applicator 25 adheres to the inner peripheral metal surface of the through-hole of the punch 22, the anaerobic adhesive may harden and become impossible to remove.

[0060] Therefore, it is desirable that the metal inner peripheral surface of the punch 22 includes a resin sleeve 24S. The resin sleeve 24S is particularly preferably made of an antistatic material. This can prevent the adhesive from being misaligned due to static electricity when it is sprayed into the resin sleeve 24S and passes through it.

[0061] As a specific example, the resin sleeve 24S can be made of MC nylon (monomer cast nylon). MC nylon is a type of polyamide (PA) resin known as an engineering plastic (ENPLA), a resin whose properties are improved by polymerizing and molding the main raw material, nylon monomer, under atmospheric pressure. This polymerization and molding method is called the cast method, and nylon produced by the cast method has different properties from standard injection-molded or extrusion-molded products, so nylon produced by the cast method is distinguished by the name MC nylon = monomer cast nylon.

[0062] A representative example of the resin sleeve 24S having an antistatic function is MC nylon "MC501CDR6-antistatic grade" manufactured by Mitsubishi Chemical Advanced Materials Corporation. This has an electrical resistance value (volume resistivity) of 10 ８ ~10 １０ It has a resistance of Ω·cm or less, making it a material that is difficult to charge with static electricity.

[0063] DESCRIPTION OF SYMBOLS 10...Thin steel plate 10a...Iron core 20...Upper die 22...Outer shape punching punch 24...Adhesive discharge nozzle 24S...Resin sleeve 25...Adhesive application device 26...Stripper plate 30...Lower die 32...Die plate 32A...Die 32a...Die hole 40...Receiving device 40a...Back pressure plate portion 40b...Holding portion 40b 41...Squeeze ring 50...Control device 60...Impact absorbing member 70...Restricting member CS...Sealed space HS...Communicating space

Claims

1. A method for manufacturing laminated iron cores in which iron cores are punched out from intermittently transported strip-shaped thin steel plate, glued, and stacked in order, the method comprising: providing an adhesive discharge nozzle that sprays adhesive from the underside of a contour punch placed in an upper die; the punch descends into a die hole formed in a die held in a lower die to punch out iron cores from the strip-shaped thin steel plate; the punch then rises and separates from the die hole; and at the point when the discharge space surrounded by the underside of the punch and the die members containing the punched iron cores is connected to the atmosphere, adhesive is sprayed from the adhesive discharge nozzle onto the top surface of the punched iron cores.

2. A method for manufacturing a laminated iron core as set forth in claim 1, further comprising: a stripper plate provided on the upper die for restricting vertical movement of the thin steel plate at its lowest position when the punch is punching out the strip-shaped thin steel plate; the discharge space comprising the underside of the punch, the punched iron core, and the stripper plate; the discharge space being configured to communicate with the atmosphere when the stripper plate separates from the thin steel plate; and adhesive being sprayed from the adhesive discharge nozzle onto the top surface of the punched iron core when the discharge space is communicated with the atmosphere.

3. A method for manufacturing a laminated core according to claim 1 or 2, wherein the point of communication with the atmosphere is linked to a press angle signal, and adhesive is sprayed from the adhesive discharge nozzle onto the top surface of the punched core based on the press angle signal.

4. A method for manufacturing a laminated core as described in claim 1, wherein the adhesive discharge nozzle has its lower end positioned above the lower surface of the punch for punching the outer shape, and the lower end of the adhesive discharge nozzle is positioned facing the opening on the lower surface of the punch for punching the outer shape.

5. A method for manufacturing a laminated core according to claim 1, wherein the lower end of the accommodation hole of the punch in which the adhesive discharge nozzle is provided has an enlarged surface that expands toward the lower surface of the punch.

6. A method for manufacturing a laminated core according to claim 1, wherein the adhesive discharge nozzle is provided so that its vertical position can be adjusted relative to the punch.

7. A method for manufacturing a laminated core according to claim 1, wherein the adhesive is ejected from the adhesive ejection nozzle in a direction toward the outer periphery of the laminated core.

8. A method for manufacturing a laminated core according to claim 1, wherein the laminated core is pressed between the punch and a back pressure plate, and is laterally pressed by a squeeze ring.

9. A method for manufacturing a laminated core according to claim 8, wherein the back pressure of said back pressure plate and the lateral pressure of said squeeze ring are adjustable.

10. A method for manufacturing a laminated core as claimed in claim 1 or 2, comprising a die plate for holding the die and a rotary lamination mechanism for rotating the laminated core around its axis, and a rotation step for rotating the laminated core a predetermined angle around its axis by the rotary lamination mechanism after spraying adhesive from the adhesive discharge nozzle onto the top surface of the punched-out core, and after rotating the laminated core around its axis by the rotation step, pressure is applied to the thin steel plate of the laminated core by the underside of the punch during the next outer shape punching.

11. A method for manufacturing a laminated core as described in claim 10, wherein by rotating the laminated core around its axis in the rotation process, in a plan view of the core, at least one of the multiple adhesive injection positions on the top surface of the previously punched core and the multiple pressure positions on the top surface of the core during the next outline punching is in a different relationship.

12. A laminated iron core manufacturing device in which iron cores are punched out from intermittently transported strip-shaped thin steel plate, glued, and laminated in order, comprising: an adhesive discharge nozzle that sprays adhesive from the underside of a contour punch arranged in an upper mold; means for lowering the punch into a die hole formed in a die held in a lower mold to punch out iron cores from the strip-shaped thin steel plate; and adhesive spraying means for spraying adhesive from the adhesive discharge nozzle onto the upper surface of the punched iron core when the punch rises and separates from the die hole and the discharge space surrounded by the underside of the punch and the die member containing the punched iron core communicates with the atmosphere.

13. A laminated core manufacturing device as set forth in claim 12, wherein an outer shape punch and an adhesive applicator having an adhesive discharge nozzle for spraying adhesive from the underside of the outer shape punch are arranged so as to rise and fall integrally with the upper die, and the adhesive applicator is provided within the space of the upper die via elastic shock absorbing members above and below it.

14. The laminated core manufacturing apparatus of claim 12, wherein the adhesive dispensing nozzle includes a resin sleeve containing an antistatic material.

15. A laminated core manufacturing device as described in claim 12, wherein the punch for punching the outer shape and an adhesive application device having an adhesive discharge nozzle for spraying adhesive from the underside of the punch for punching the outer shape are each arranged to rise and fall integrally with the upper mold, and the adhesive application device provided within the space of the upper mold is fixed to the upper mold within the space of the upper mold by a position control member.

16. The laminated core manufacturing apparatus according to claim 15, wherein the adhesive application device provided within the space of the upper die has an upper shock absorbing member on its upper surface and a lower shock absorbing member on its lower surface.

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