Manufacturing apparatus and method for laminated iron cores

Abstract

Ensure that the adhesive is applied accurately to the surface to which it will be applied. [Solution] A guide member 100 is provided to guide the movement of the strip-shaped thin steel sheet F along the intermittent transport direction of the strip-shaped thin steel sheet F and to restrict its upward movement, and an adhesive application device 50 is provided to apply adhesive to the adhesive application surface of the portion corresponding to the iron core thin sheet A(W).

Description

Technical Field

[0001] The present invention relates to an apparatus and a method for manufacturing a laminated core, and more particularly to an apparatus and a method for manufacturing an adhesive-type laminated core formed by adhering a plurality of laminated thin iron cores with an adhesive.

Background Art

[0002] As a laminated core used for a stator or a rotor of a rotating electrical machine, thin iron cores punched in a progressive die including a plurality of punching dies (die sets) of a punch and a die from a intermittently transferred strip-shaped thin steel sheet are sequentially laminated in a die and adhered with an adhesive such as an epoxy resin-based adhesive. An adhesive-type laminated core is known (Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The application of the adhesive to the adhesive application surface of the thin iron core (strip-shaped thin steel sheet) needs to be accurately performed at a predetermined position on the adhesive application surface so that the adhesive strength as designed can be obtained and there is no dripping of the adhesive to the outside. Also, it is required that the adhesive on the adhesive application surface does not spread or scatter around due to vibration of the thin iron core (strip-shaped thin steel sheet) during its movement.

[0005] The problem to be solved by the present invention is to accurately apply the adhesive to the adhesive application surface.

Means for Solving the Problems

[0006] The laminated core manufacturing apparatus according to the present invention is a laminated core manufacturing apparatus that laminates and bonds core sheets punched out into a predetermined shape from a strip of thin steel sheet, and comprises an upper holder and a lower holder, a plurality of punches and dies provided on the upper holder and the lower holder respectively to sequentially punch out core sheets from a strip of thin steel sheet that is intermittently transported, a guide member provided on the lower holder to guide the transport of the strip of thin steel sheet along the intermittent transport direction and to restrict the upward movement of the strip of thin steel sheet, and an adhesive application device provided on at least one of the upper holder and the lower holder to apply adhesive to the adhesive application surface of the strip of thin steel sheet corresponding to the core sheet.

[0007] With this configuration, the adhesive is applied to the adhesive-coated surface of the strip-shaped thin steel sheet while its upward movement is restricted by the guide member, thus ensuring accurate application of the adhesive to the adhesive-coated surface.

[0008] The guide member has a structure that restricts the upward movement of the strip-shaped thin steel plate by contacting it, as well as a structure that restricts the lateral movement of the strip-shaped thin steel plate by contacting it, thereby guiding the intermittent transport of the strip-shaped thin steel plate.

[0009] In this case, the adhesive is applied to the adhesive-coated surface of the strip-shaped thin steel sheet while its movement in the left-right direction is restricted in addition to its upward movement, thus ensuring more accurate application of the adhesive to the adhesive-coated surface.

[0010] The manufacturing apparatus for laminated iron cores according to the present invention preferably further includes a pilot pin provided in the upper holder and inserted into a pilot hole formed in the strip of thin steel sheet in order to position the strip of thin steel sheet at each transfer position.

[0011] With this configuration, the pilot pin is inserted into a pilot hole formed in the strip of thin steel sheet, and the adhesive is applied to the adhesive-coated surface while the adhesive is being applied. This ensures that the adhesive is applied accurately to the adhesive-coated surface.

[0012] The manufacturing apparatus for laminated iron cores according to the present invention preferably further comprises a stripper plate provided on the upper holder so as to be displaceable in the vertical direction and having a lower surface facing the upper surface of the die.

[0013] With this configuration, the stripper plate can restrict the vertical movement of the thin steel strip, ensuring that the adhesive is applied accurately to the adhesive-coated surface.

[0014] The manufacturing apparatus for laminated iron cores according to the present invention preferably further includes a stripper spring that biases the stripper plate toward the lower holder, and the stripper plate is configured to press the strip-shaped thin steel sheet against the upper surface of the die by the spring force of the stripper spring.

[0015] With this configuration, the adhesive can be applied to the adhesive application surface when the strip-shaped thin steel sheet is pressed against the die by the stripper plate, or while it is pressed against the die, ensuring accurate application of the adhesive to the adhesive application surface.

[0016] In the manufacturing apparatus for laminated iron cores according to the present invention, the stripper plate is preferably configured to press the strip of thin steel sheet against the upper surface of the die until the punch is removed from the die, and more preferably until the punch is removed from the strip of thin steel sheet.

[0017] With this configuration, during the upward movement of the upper holder after punching, the strip of thin steel sheet is kept pressed against the upper surface of the die by the stripper plate until the punch is removed from the die or until the punch is removed from the strip of thin steel sheet. This suppresses the vibration of the strip of thin steel sheet during the upward movement of the upper holder and prevents the adhesive applied to the strip of thin steel sheet from scattering.

[0018] In the manufacturing apparatus for laminated iron cores according to the present invention, preferably, the pilot pin includes a straight shaft portion, and the straight shaft portion is positioned to protrude below the lower surface of the stripper plate when the stripper plate is in its lowest position relative to the upper holder due to the biasing force of the stripper spring.

[0019] With this configuration, during the descent process of the upper holder, the straight shaft portion of the pilot pin enters the pilot hole before the lower surface of the stripper plate comes into contact with the strip of thin steel sheet. Therefore, the positioning of the strip of thin steel sheet is performed smoothly without being hindered by the restraint of the strip of thin steel sheet by the stripper plate.

[0020] The manufacturing apparatus for laminated iron cores according to the present invention preferably further includes a plurality of lifters provided on the lower holder so as to be displaceable in the vertical direction, which contact the lower surface of the strip-shaped thin steel sheet to separate the strip-shaped thin steel sheet from the upper surface of the die.

[0021] With this configuration, the strip of thin steel sheet can be lifted from the top surface of the die during intermittent transfer, and even if the adhesive application surface is on the underside of the strip of thin steel sheet, the adhesive applied to the adhesive application surface will not be rubbed off by the top surface of the die.

[0022] The manufacturing apparatus for a laminated core according to the present invention preferably further includes a plurality of lifters provided on the lower holder so as to be vertically displaceable, which abut against the lower surface of the strip-shaped thin steel plate to separate the strip-shaped thin steel plate from the upper surface of the die, and a plurality of springs for lifters which bias each of the lifters upward to separate the strip-shaped thin steel plate from the upper surface of the die in a state where the stripper plate abuts against the upper surface of the strip-shaped thin steel plate and each of the lifters abuts against the lower surface of the strip-shaped thin steel plate when the stripper plate ascends.

[0023] According to this configuration, after the application of the adhesive, the core thin plate is lifted up (separated state) while being supported from above and below by the lifters and the stripper plate, so that the strip-shaped thin steel plate is prevented from swaying during the lifting-up process, and the adhesive applied to the strip-shaped thin steel plate is prevented from scattering.

[0024] The manufacturing apparatus for a laminated core according to the present invention preferably has each of the lifters also serving as the guide member.

[0025] According to this configuration, the number of parts can be reduced.

[0026] When the lifter also serves as the guide member, the lifter may be constituted by a lifter pin having a circumferential groove on its upper outer periphery, and the left and right side edges of the strip-shaped thin steel plate may enter the circumferential groove. In this case, when the strip-shaped thin steel plate is lifted up by the lifter, the strip-shaped thin steel plate is restricted from moving upward and downward according to the vertical width of the circumferential groove, and the fluttering of the strip-shaped thin steel plate during intermittent transfer is suppressed.

[0027] The manufacturing apparatus for a laminated core according to the present invention preferably has the adhesive application device of a transfer type including a plurality of discharge holes for discharging the adhesive toward the adhesive application surface in order to transfer the adhesive to each of a plurality of predetermined positions on the adhesive application surface.

[0028] According to this configuration, the adhesive is accurately applied to the adhesive application surface by transfer.

[0029] The manufacturing apparatus for laminated iron cores according to the present invention preferably includes an adhesive application apparatus which comprises an adhesive supply apparatus that supplies the adhesive to each of the discharge holes at a predetermined pressure, and a reciprocating drive apparatus that moves each of the discharge holes between a transfer position where the adhesive can be transferred to the adhesive application surface and a non-transfer position where the adhesive cannot be transferred by retracting from the transfer position.

[0030] With this configuration, by selectively setting the position of the discharge hole to either a transfer position or a non-transfer position, the transfer and non-transfer of the adhesive to the adhesive-coated surface can be selectively set.

[0031] The laminated core manufacturing apparatus according to the present invention is a laminated core manufacturing apparatus that laminates and bonds core sheets punched into a predetermined shape from a strip of thin steel sheet, comprising an upper holder and a lower holder, a plurality of punches and dies provided on the upper holder and the lower holder for sequentially punching core sheets from a strip of thin steel sheet that is intermittently transported, a pilot pin provided on the upper holder and fitted into a pilot hole formed in the strip of thin steel sheet to position the strip of thin steel sheet at each transport position, a stripper plate provided on the upper holder so as to be displaceable in the vertical direction and having a lower surface facing the upper surface of the die, and the stripper plate The device includes a stripper spring that biases toward the lower holder, a plurality of lifters provided on the lower holder so as to be displaceable in the vertical direction and in contact with the lower surface of the strip-shaped thin steel plate, a plurality of lifter springs that bias each lifter upward to lift the strip-shaped thin steel plate above the upper surface of the die when the stripper plate rises and the stripper plate is in contact with the upper surface of the strip-shaped thin steel plate and each lifter is in contact with the lower surface of the strip-shaped thin steel plate, and an adhesive application device provided on at least one of the upper holder and the lower holder for applying adhesive to the adhesive application surface of the strip-shaped thin steel plate corresponding to the iron core thin plate.

[0032] With this configuration, the pilot pin is inserted into the pilot hole of the strip of thin steel sheet, and the adhesive can be applied to the adhesive application surface when the strip of thin steel sheet is pressed against the upper surface of the die by the stripper plate, or while it is pressed against the die, thus ensuring accurate application of the adhesive to the adhesive application surface. Moreover, after the adhesive is applied, the strip of thin steel sheet is returned to the lifted state while being supported from above and below by the lifter and stripper plate, so that the strip of thin steel sheet does not shake during the lifting process and the scattering of the adhesive applied to the strip of thin steel sheet is suppressed.

[0033] The present invention relates to a method for manufacturing a laminated iron core, comprising laminating and bonding iron core sheets punched out into a predetermined shape from a strip of thin steel sheet using a press device having an upper holder and a lower holder, the method comprising: a transfer step of intermittently transferring the strip of thin steel sheet while restricting its upward movement with a guide member provided on the lower holder and guiding its transfer along the intermittent transfer direction; a punching step of punching out the outer shape of the iron core sheet with a punch and die provided on the upper holder and the lower holder as the upper holder is lowered; and a coating step of applying an adhesive to the adhesive application surface of the strip of thin steel sheet using an adhesive application device provided on at least one of the upper holder and the lower holder before the punching step.

[0034] According to this manufacturing method, the intermittent transport of the strip-shaped thin steel sheet is guided by a guide member, and the upward movement of the strip-shaped thin steel sheet is restricted by the guide member. With this in place, the adhesive is applied to the adhesive-coated surface, ensuring accurate application of the adhesive to the adhesive-coated surface.

[0035] In the manufacturing method of laminated iron core according to the present invention, preferably, the transfer step involves intermittently transferring the strip-shaped thin steel sheet in a lifted state away from the upper surface of the die provided on the lower holder, using a lifter that is vertically movable on the lower holder and biased upward by a lifter spring, while the upper holder is in a raised state.

[0036] According to this manufacturing method, even if the adhesive-coated surface is the underside of a strip of thin steel sheet, the adhesive applied to the adhesive-coated surface will not be rubbed off by the upper surface of the die.

[0037] The method for manufacturing a laminated iron core according to the present invention preferably further includes a pilot insertion step in which a pilot pin provided on the upper holder is inserted into a pilot hole formed in the strip-shaped thin steel sheet while the upper holder is descending after the completion of the transfer step.

[0038] According to this manufacturing method, the strip-shaped thin steel sheet is precisely positioned, and therefore the adhesive is applied precisely to the adhesive-coated surface.

[0039] The method for manufacturing a laminated iron core according to the present invention preferably further includes a pressing step in which, while the upper holder is descending after the completion of the pilot insertion step, the strip-shaped thin steel plate is pressed against the upper surface of a die provided on the lower holder, accompanied by the downward movement of the lifter.

[0040] According to this manufacturing method, the strip of thin steel is pressed against the upper surface of the die after the pilot insertion process is completed. In other words, the pilot pin is inserted into the pilot hole of the strip of thin steel before the strip is pressed against the upper surface of the die and restrained. This ensures that the insertion of the pilot pin into the pilot hole is smooth.

[0041] The method for manufacturing a laminated iron core according to the present invention preferably involves the coating step of applying adhesive when the pilot pin is inserted into the pilot hole and the strip-shaped thin steel sheet is pressed against the upper surface of the die by the stripper plate as the lifter moves downward, or while the sheet is pressed against the die, and after the application of the adhesive is completed, the upper holder rises, causing the lifter to move upward as the lifter contacts the lower surface of the strip-shaped thin steel sheet and the stripper plate contacts the upper surface of the strip-shaped thin steel sheet, thereby returning the strip-shaped thin steel sheet to the lifted state.

[0042] According to this manufacturing method, the adhesive is applied to the adhesive-coated surface when the strip-shaped thin steel sheet is pressed against the die by the stripper plate, or while it is pressed against the die, thus ensuring accurate application of the adhesive to the adhesive-coated surface. Furthermore, the vibration of the strip-shaped thin steel sheet is suppressed during the upward movement of the upper holder, and the scattering of the adhesive applied to the strip-shaped thin steel sheet is suppressed.

[0043] The present invention relates to a method for manufacturing a laminated iron core, comprising laminating and bonding iron core thin sheets punched into a predetermined shape from a strip of thin steel sheet using a press device having an upper holder and a lower holder, wherein, when the upper holder is raised, the strip of thin steel sheet is intermittently transported in a lifted state away from the upper surface of a die provided on the lower holder by a lifter that is vertically movable and biased upward by a lifter spring, and is biased upward by a lifter spring. The process includes: inserting a pilot pin provided on the upper holder into a pilot hole formed in the strip-shaped thin steel plate while the upper holder is descending after the completion of the transfer process; pressing a stripper plate suspended from the upper holder by a stripper spring against the upper surface of a die provided on the lower holder while the upper holder is descending after the completion of the pilot insertion process, accompanied by the downward movement of the lifter; and multiple pins set in a line at intervals in the intermittent transfer direction. At each pressing position, after the pressing process is completed, the upper holder is lowered further to punch out the inner and outer shapes of the strip-shaped thin steel sheet sequentially using a set of molds consisting of punches and dies provided on the upper and lower holders. Between the pressing position for punching out the inner shape and the pressing position for punching out the outer shape, an adhesive application device is set in a line with these pressing positions and is provided on at least one of the upper and lower holders to apply adhesive to the adhesive application surface of the strip-shaped thin steel sheet. The process comprises the steps of: applying adhesive when the pilot pin is inserted into the pilot hole and the strip of thin steel sheet is pressed against the upper surface of the die by the stripper plate as the lifter moves downward, or while the strip of thin steel sheet is pressed against the die; and returning the strip of thin steel sheet to the lifted state as the upper holder rises after the application of adhesive is complete, with the lifter moving upward as the lifter contacts the lower surface of the thin steel sheet and the stripper plate contacts the upper surface of the thin steel sheet.

[0044] According to this manufacturing method, the pilot pin is inserted into the pilot hole of the strip-shaped thin steel sheet, and the adhesive is applied to the adhesive application surface when the strip-shaped thin steel sheet is pressed against the upper surface of the die by the stripper plate, or while it is pressed against the die, thus ensuring accurate application of the adhesive to the adhesive application surface. Furthermore, after the adhesive is applied, the strip-shaped thin steel sheet is returned to the lifted state while being supported from above and below by the lifter and the stripper plate, so that the strip-shaped thin steel sheet does not shake during the lifting process, and the scattering of the adhesive applied to the strip-shaped thin steel sheet is suppressed.

[0045] The method for manufacturing a laminated iron core according to the present invention preferably includes a coating step of discharging an adhesive from each of a plurality of discharge holes toward the adhesive coating surface and transferring the adhesive to each of a plurality of predetermined positions on the adhesive coating surface.

[0046] According to this manufacturing method, the adhesive is applied to the adhesive-coated surface in a fine and precise manner by transfer.

[0047] The present invention relates to a method for manufacturing a laminated iron core, wherein the iron core thin sheet includes a plurality of teeth portions, and each teeth portion has at least one of the coating points.

[0048] According to this manufacturing method, the bonding of adjacent iron core thin sheets is also performed at the teeth portion, resulting in the production of laminated iron cores with high adhesive strength. [Effects of the Invention]

[0049] According to the manufacturing apparatus and manufacturing method for laminated iron cores of the present invention, the adhesive is applied accurately to the adhesive-coated surface. [Brief explanation of the drawing]

[0050] [Figure 1] Plan view showing an example of a thin iron core plate used in the stator of a stepping motor. [Figure 2] Figure 1 is an explanatory diagram showing the strip layout in a progressive die machine used for manufacturing thin iron core sheets. [Figure 3] Plan view showing a schematic representation of a thin iron core sheet manufactured by the laminated iron core manufacturing apparatus and manufacturing method according to the present invention. [Figure 4] Figure 3 is an explanatory diagram showing one embodiment of a strip layout in a progressive die machine used for manufacturing laminated iron cores. [Figure 5] A schematic diagram showing one embodiment of the manufacturing apparatus for laminated iron cores according to the present invention. [Figure 6] Cross-sectional view showing the adhesive device used in the laminated iron core manufacturing apparatus according to this embodiment. [Figure 7] Enlarged cross-sectional view of the main part of the adhesive device according to this embodiment. [Figure 8A] Cross-sectional view of the internal punching station of the manufacturing apparatus according to this embodiment at top dead center. [Figure 8B] Cross-sectional view of the adhesive application station of the manufacturing apparatus according to this embodiment in the top dead center position. [Figure 9A] Cross-sectional view of the internal die-cutting station of the manufacturing apparatus according to this embodiment during the descent process 1. [Figure 9B] Cross-sectional view of the adhesive application station of the manufacturing apparatus according to this embodiment during the descent process 1. [Figure 10A] Cross-sectional view of the internal die-cutting station of the manufacturing apparatus according to this embodiment during the descent process 2. [Figure 10B] Cross-sectional view of the adhesive application station of the manufacturing apparatus according to this embodiment during the descent process 2. [Figure 11A] Cross-sectional view of the internal die-cutting station of the manufacturing apparatus according to this embodiment during the descent process 3. [Figure 11B] Cross-sectional view of the adhesive application station of the manufacturing apparatus according to this embodiment during the descent process 3. [Figure 12A] Cross-sectional view of the internal punching station of the manufacturing apparatus according to this embodiment in the bottom dead center position. [Figure 12B] Cross-sectional view of the adhesive application station of the manufacturing apparatus according to this embodiment in the bottom dead center position. [Figure 13A] Cross-sectional view of the internal die-cutting station of the manufacturing apparatus according to this embodiment during the lifting process 1. [Figure 13B] Cross-sectional view of the adhesive application station of the manufacturing apparatus according to this embodiment during the lifting process 1. [Figure 14A] Cross-sectional view of the internal die-cutting station of the manufacturing apparatus according to this embodiment during the lifting process 2. [Figure 14B] Cross-sectional view of the adhesive application station of the manufacturing apparatus according to this embodiment during the lifting process 2. [Figure 15A] Cross-sectional view of the internal die-cutting station of the manufacturing apparatus according to this embodiment during the lifting process 3. [Figure 15B] Cross-sectional view of the adhesive application station of the manufacturing apparatus according to this embodiment during the lifting process 3. [Figure 16] Enlarged cross-sectional view of the lift-up section in the top dead center position of the manufacturing apparatus according to this embodiment. [Figure 17] Enlarged cross-sectional view of the lift-up section during the lowering process 2 of the manufacturing apparatus according to this embodiment. [Figure 18] Enlarged cross-sectional view of the lift-up section in the bottom dead center position of the manufacturing apparatus according to this embodiment. [Figure 19] Enlarged cross-sectional view of the lift-up section during the lifting process 1 of the manufacturing apparatus according to this embodiment. [Figure 20] Figure 3 is an explanatory diagram showing another embodiment of the strip layout in a progressive die machine used for manufacturing laminated iron cores. [Figure 21] Figure 3 is an explanatory diagram showing another embodiment of the strip layout in a progressive die machine used for manufacturing laminated iron cores. [Figure 22A] Cross-sectional view of the internal punching station of a manufacturing apparatus in the top dead center position according to another embodiment. [Figure 22B] Cross-sectional view of the adhesive application station of a manufacturing apparatus according to another embodiment, in the top dead center position. [Modes for carrying out the invention]

[0051] Preferred embodiments of the present invention will be described with reference to the accompanying drawings.

[0052] First, as a specific example of a laminated core, we will explain the laminated core used in the stator of a stepping motor with reference to Figure 1.

[0053] The laminated iron core is made by laminating multiple iron core sheets A of the same shape. The iron core sheets A are made by punching out strip-shaped thin steel sheets, i.e., hoop material F, into a predetermined shape using a progressive die press. They have an annular yoke portion B formed by outer punching, multiple teeth portions (magnetic pole portions) C formed by inner punching that protrude radially inward from the yoke portion B, and multiple through holes D formed by punching in the yoke portion B. Adjacent pieces are bonded together by adhesive applied in a dotted pattern to multiple application points E1, E2 on one surface (adhesive application surface) of the yoke portion B and teeth portion C.

[0054] Adhesives used here include anaerobic adhesives (adhesive + curing accelerator), one-component epoxy resin adhesives, two-component epoxy resin adhesives (first adhesive component + second adhesive component or main component + initiator), thermosetting adhesives such as acrylic resin adhesives, and moisture-curing adhesives.

[0055] Note that in Figure 1, for the sake of explanation, the application points E1 and E2 are shown on the upper surface of the iron core sheet A. However, in reality, the application points E1 and E2 are set on the lower surface of the iron core sheet A so that the adhesive is applied to the lower surface (adhesive application surface) of the iron core sheet A.

[0056] The manufacturing process for the laminated iron core involves intermittent transfer of the hoop material F in a progressive die device (laminated iron core manufacturing device), and as shown in Figure 2, it sequentially includes the first half punching process 1-5, adhesive application process 6, outer shape punching process 7, rotary lamination process 8, and heating process 9.

[0057] In the first half of the punching process, the following processes are carried out sequentially using die sets (not shown) with punches and dies of shapes corresponding to each punching operation: punching 1 of pilot holes P in the hoop material F, punching 2 of internal pilot holes d1 and through holes D, punching 3 of slot sections S1, punching 4 of internal shapes d2, and punching 5 of inter-tooth slits S2 and tooth tip groove sections m. This forms the basic shape of the iron core sheet A, excluding the punching of the outer shape.

[0058] The adhesive application process 6 is performed after the first half punching processes 1 to 5. The adhesive is applied to the hoop material F in a circular dot pattern at multiple application points E1, which are set on the yoke section B at positions corresponding to each slot section S1, and at two application points E2 on each tooth section C, as detailed in Figure 1. A known anaerobic adhesive is used as the adhesive. Also, in Figure 2, for the sake of explanation, each application point E1 and E2 is shown on the upper side of the iron core sheet A, but in reality, each application point E1 and E2 is set on the lower side of the iron core sheet A.

[0059] The outer shape punching process 7 is performed after the completion of the adhesive application process 6. The outer shape punching process 7 is performed by a die set (not shown) consisting of a punch and die with a shape corresponding to the outer shape d3 of the iron core sheet A.

[0060] The rotary lamination process 8 is performed following the outer shape punching process 7. The die used in the outer shape punching process 7 is a rotary die, which rotates around its central axis by a predetermined angle, for example, 90 degrees, each time an outer shape of one iron core sheet A is punched out. As a result, the iron core sheets A punched out in the outer shape punching process 7 are sequentially stacked on top of the group of iron core sheets G that have already been punched and are stacked inside the rotary die, while changing their position around the central axis. This rotary lamination eliminates the effects of minute thickness deviations that may occur in each iron core sheet A, allowing for precise control of the stacking thickness of the product (laminated iron core). The group of iron core sheets G are then sequentially pushed into a squeeze ring (not shown) located below the rotary die.

[0061] When a newly punched iron core sheet A is laminated onto the iron core sheet group G, the lower surface of the newly punched iron core sheet A comes into close contact with the upper surface of the iron core sheet A located in the uppermost layer of the iron core sheet group G. As a result, the adhesive applied in a circular dot pattern to application points E1 and E2 on the lower surface of the newly punched iron core sheet A mixes with the curing accelerator that has been pre-applied to the upper surface of the iron core sheet A located in the uppermost layer.

[0062] The heating process 9 is performed after the completion of the rotary lamination process 8. A heating device (not shown) is provided at the bottom of the squeeze ring, and the iron core sheet group G is heated by this heating device as it moves downward. This allows the adhesive between each iron core sheet A to harden through heating, thereby increasing the adhesive strength. As such an adhesive heating device, for example, a heater device that blows hot air onto the iron core sheet group G can be used. After heating by the heating device, the iron core sheet group G is separated at the position of each iron core sheet A for weighing, and a laminated iron core M consisting of a predetermined number of iron core sheets A is completed.

[0063] Next, one embodiment of the laminated iron core manufacturing apparatus 10 will be described with reference to Figures 4 and 5. For the sake of simplicity, the following description will describe an iron core sheet W that is schematically represented in an annular shape, as shown in Figure 3. The iron core sheet W is formed by punching out a circular inner shape IS and a circular outer shape OS, and adhesive is applied in a dotted manner to each of the multiple application points E set in the circumferential direction of the lower surface (adhesive application surface) of the annular portion R obtained by these punchings.

[0064] The manufacturing apparatus 10 uses a progressive die system and, as shown in Figures 4 and 5, has a pilot hole punching station I, an internal die punching station II, an idle station III, an adhesive application station IV, an idle station V, an external die punching station VI, and an idle station VII in the progressive direction. Stations I, II, IV, and VI, excluding idle stations III, V, and VII, perform their respective processes under the intermittent transfer of the hoop material F in the progressive direction. The punching sections performed at pilot hole punching station I, internal die punching station II, and external die punching station VI are indicated by diagonal lines. Idle stations III, V, and VII perform idle feeding of the hoop material F.

[0065] The manufacturing apparatus 10 includes a plate-shaped upper holder 12 fixed to the lower surface of the upper ram (not shown) of the press machine, and a plate-shaped lower holder 14 fixed to the upper surface of the lower table (not shown) of the press machine, facing the upper holder 12.

[0066] At the lower part of the upper holder 12, a backing plate 16 and a punch plate 18 are attached to the pilot hole punching punch 20, the inner shape punching punch 22, and the outer shape punching punch 24, respectively, at positions corresponding to stations I, II, and VI.

[0067] A stripper 28 is mounted below the upper holder 12 by suspension bolts (not shown) so as to be displaceable in the vertical direction. The stripper 28's lowest position relative to the upper holder 12 is set by suspension support by the suspension bolts (not shown). The stripper 28 is composed of a joint between a plate-shaped stripper body 30 and a stripper plate 32, with the lower surface 33 of the stripper plate 32 facing the upper surface 47 of the die plate 40 and each die 42, 44, 46, which will be described later. In other words, the stripper plate 32 has a lower surface 33 that faces the upper surface 47 of the die plate 40 and each die 42, 44, 46. Punch insertion holes 34, 36, and 38 are formed in the stripper plate 32 through which each punch 20, 22, 24 passes.

[0068] A plate-shaped die plate 40 is attached to the upper surface of the lower holder 14. On the die plate 40, a pilot hole punching die 42, an internal shape punching die 44, and an external shape punching die 46 are attached at positions corresponding to each punching station I, II, and VI. The pilot hole punching punch 20 and the pilot hole punching die 42, the internal shape punching punch 22 and the internal shape punching die 44, and the external shape punching punch 24 and the external shape punching die 46 correspond to each other and each forms a die set.

[0069] Furthermore, since the upper surfaces of the die plate 40 and each die 42, die 44, and die 46 are flush, these upper surfaces will collectively be referred to as the upper surface 47 of the die plate 40.

[0070] An adhesive application device 50 is provided at a position on the die plate 40 corresponding to the adhesive application station IV. The adhesive application device 50 moves up and down by a cam mechanism 52 driven by a drive device 54, and when in the raised position, it applies (transfers) adhesive in a dotted manner to multiple locations (application points E) on the underside of the hoop material F with each press operation, except during weighing to set the number of stacked iron core thin plates W.

[0071] At the pilot hole punching station I, a pilot hole P (see Figure 4) is punched into the hoop material F with each press operation, or in other words, with each intermittent transfer of the hoop material F, using a pilot hole punching punch 20 and a pilot hole punching die 42. The pilot holes P are provided near the edges on both sides (left and right) in the direction of intermittent transfer (forward feeding) of the hoop material F.

[0072] In the internal die punching station II, the internal die punch 22 and the internal die punch 44 punch out an internal shape IS (see Figure 4) into the hoop material F with each intermittent transfer of the hoop material F.

[0073] At adhesive application station IV, adhesive is applied in a circular dot pattern to application points E on the underside of the hoop material F by the adhesive application device 50, which is located in an elevated position. During weighing, which sets the number of stacked iron core plates W that occur with each predetermined intermittent transfer, the adhesive application device 50 is lowered to the lowered position, and the application of adhesive to the hoop material F is paused.

[0074] The outer shape punching station VI punches an outer shape OS (see Figure 4) out of the hoop material F using an outer shape punching punch 24 and an outer shape punching die 46. This punching completes the iron core sheet W, which then descends and is sequentially stacked inside the outer shape punching die 46. The iron core sheets W stacked inside the outer shape punching die 46 are bonded together by the adhesive at application point E, except for those used for weighing and for which adhesive has not been applied, as they overlap each other vertically.

[0075] The laminate of iron core thin sheets W is removed downward and outward from the discharge hole 48 formed in the lower holder 14 at the outer shape punching station VI, and is transported to a post-treatment process for heat curing of the adhesive as needed.

[0076] Next, the details of the adhesive application apparatus 50 will be described with reference to Figures 6 and 7.

[0077] The adhesive application device 50 is of the transfer type and has an application stage 60 formed by a connection between an upper block 58 and a lower block 59. The application stage 60 is fitted into a holding hole 56 formed in the lower holder 14 and the die plate 40 so as to be able to move up and down.

[0078] A cam mechanism 52 is provided at the bottom of the coating table 60. The cam mechanism 52 includes a fixed cam 74, which is a plate cam fixed to the bottom of the lower block 59, and a movable cam 76, which is a plate cam movably provided at the bottom of the lower block 59. The movable cam 76 is connected to a drive device 54 and is driven by the drive device 54 to reciprocate in the left-right direction as seen in Figure 6. The fixed cam 74 includes a sawtooth-shaped portion on its lower surface, which has alternating sawtooth peaks 74A and sawtooth valleys 74B in the left-right direction, and the movable cam 76 includes a sawtooth-shaped portion on its upper surface, which has alternating sawtooth peaks 76A and sawtooth valleys 76B.

[0079] As shown in the diagram, when the movable cam 76 is positioned so that the sawtooth ridges 74A of the fixed cam 74 and the sawtooth ridges 76A of the movable cam 76 are aligned, the coating table 60 is in the raised position (transfer position). In the raised position, the upper surface 61 of the upper block 58 is located below the upper surface 47 of the die plate 40 by a step α.

[0080] When the movable cam 76 is driven to the left in Figure 6 by the drive unit 54, and the movable cam 76 is positioned so that the sawtooth valleys 74B of the fixed cam 74 and the sawtooth peaks 76A of the movable cam 76 are aligned with each other, the coating table 60 and the fixed cam 74 descend (retract downwards), and the coating table 60 is positioned in the lowered position. In this lowered position (non-transfer position), the upper surface 61 of the upper block 58 is positioned below the upper surface 47 of the die plate 40 with a large step difference exceeding the step difference α.

[0081] The upper block 58 has an adhesive reservoir 62 formed by an annular groove, and a plurality of discharge holes 64 that extend vertically from the adhesive reservoir 62 to the horizontal upper surface 61 of the upper block 58 and open onto the upper surface 61. Each discharge hole 64 is positioned to correspond to each application point E of the hoop material F (thin iron core plate W) located at the adhesive application station IV.

[0082] An internal block 66 is installed inside the upper block 58. The internal block 66 has an adhesive supply passage 68 formed therein for supplying adhesive to the adhesive reservoir 62. A flexible adhesive supply tube 70 is connected to the adhesive supply passage 68. The adhesive supply tube 70 is connected to an adhesive supply device 72. The adhesive supply device 72 pressurizes the adhesive to a predetermined pressure, measures the pressurized adhesive, and supplies it to the adhesive reservoir 62 at a predetermined flow rate via the adhesive supply tube 70 and the adhesive supply passage 68. As a result, adhesive is constantly supplied to each discharge hole 64 from the adhesive reservoir 62 at a predetermined pressure.

[0083] In this embodiment, two adhesive supply tubes 70 and two adhesive supply passages 68 are provided, supplying adhesive to two locations 180 degrees apart in the circumferential direction of the adhesive reservoir 62. However, this is not essential; the number and supply locations should be as many as necessary to ensure the supply amount of adhesive required to maintain the adhesive pressure at an appropriate level throughout the entire adhesive reservoir 62. The appropriate pressure of the adhesive is determined by the size and number of discharge holes 64 and their arrangement.

[0084] The adhesive in the adhesive reservoir 62 is discharged from each discharge hole 64 onto the application stand 60. As the pressure of the adhesive in the adhesive reservoir 62 is maintained at a predetermined value and the adhesive has a predetermined viscosity, the adhesive discharged to the outside from each discharge hole 64 constantly forms a roughly hemispherical raised portion N above the upper surface 61 of the upper block 58, as shown in Figure 7. Because the height of the raised portion N is slightly greater than the step α, when the application stand 60 is in the raised position (transfer position) and the hoop material F descends to a position where the lower surface of the hoop material F contacts the upper surface 47 of the die plate 40, the raised portion N of the adhesive at each discharge hole 64 comes into contact with the lower surface of the hoop material F, and the adhesive is transferred to each application point E in a round dot shape.

[0085] If the adhesive application device 50 intermittently forms the raised portion N, the timing is set so that the raised portion N is formed when the lower surface of the hoop material F is in contact with the upper surface 47 of the die plate 40. As a result, the adhesive is transferred in a circular dot shape to each application point E while the lower surface of the hoop material F is in contact with the upper surface 47 of the die plate 40.

[0086] The amount of adhesive transferred to each application point E can be controlled by the size (volume) of the step α and the raised portion N. Since the size of the raised portion N is quantitatively determined by the pressure of the adhesive in the adhesive reservoir 62, the viscosity of the adhesive, the inner diameter of the discharge hole 64, etc., the amount of adhesive transferred to each application point E can be set to an optimal value by optimally setting these parameters.

[0087] In the application of a transfer-type adhesive using such discharge holes 64, the minimum pitch of application points E can be set to a dimension slightly larger than the inner diameter of the discharge holes 64 by reducing the pitch between adjacent discharge holes 64. This allows application points E to be set at multiple locations on the teeth portion C, even if the teeth portion C is small. This contributes to improving the adhesive strength of the teeth portion C in the lamination bonding of multiple iron core thin plates W.

[0088] When the coating stand 60 is in the lowered position (non-transfer position), the upper surface 61 of the upper block 58 is positioned below the upper surface 47 of the die plate 40 with a step greater than the step α. Therefore, the specified size of the adhesive mound N does not come into contact with the lower surface of the hoop material F, and the adhesive is not transferred to the lower surface of the hoop material F. Consequently, when weighing to set the number of layers of iron core thin plate W, it is sufficient to move the coating stand 60 to the lowered position.

[0089] A knockout 26 is attached to the upper holder 12, as shown in Figures 8A and 8B. Figure 8A shows the internal die-cutting station II, which is representative of each die-cutting station, and Figure 8B shows the adhesive application station IV.

[0090] The knockout 26 has a lower end 26A that abuts against the upper part of the stripper body 30, a shaft portion 26C that is fitted vertically to a through hole 13 formed in the upper holder 12 so as to be movable up and down, and an upper end flange 26B located within a spring chamber 15 formed in the upper holder 12. The upper part of the spring chamber 15 is closed by a plug 17 fixed to the upper holder 12. A stripper spring (knockout spring) 29 made of a compression coil spring is provided between the plug 17 and the upper end flange 26B. The stripper spring 29 biases the knockout 26 downward.

[0091] The lowest position (bottom dead center) of the upper holder 12 is determined at the bottom dead center of the upper ram (not shown) of the press machine, as shown in Figures 12A and 12B, by the lower surface of the upper holder 12 contacting the upper surfaces of the stoppers 82 provided on both the left and right sides of the lower holder 14. When the upper holder 12 is in the lowest position, the stripper plate 32 contacts the hoop material F and, with the compression deformation of the stripper spring 29, is displaced downward relative to the upper holder 12, pressing the hoop material F against the upper surface 47 of the die plate 40.

[0092] The vertical relative displacement stroke of the stripper 28 with respect to the upper holder 12 is greater than the entry stroke of each punch 20, 22, 24 into each die 42, 44, 46. The entry stroke is the amount of entry that each punch 20, 22, 24 has into each die 42, 44, 46 when the upper holder 12 is in its lowest position, as shown in Figure 12A.

[0093] In other words, the stroke of the stripper 28, including the stripper plate 32, between its lowest position relative to the upper holder 12 and the position where the stripper 28 moves relative to the upper holder 12 with elastic deformation of the stripper spring 29 and presses the hoop material F against the upper surface 47 of the die plate 40 of the lower holder 14 is greater than the maximum entry stroke of the punches 20, 22, and 24 into the respective dies 42, 44, and 46.

[0094] With this stroke setting, during the upward movement of the upper holder 12 after punching, the stripper 28 rises together with the upper holder 12 after each punch 20, 22, and 24 has emerged from each die 42, 44, and 46 and the hoop material F, releasing the pressure on the hoop material F by the stripper 28. As a result, the hoop material F remains pressed against the upper surface 47 of the die plate 40 by the stripper 28 until each punch 20, 22, and 24 has emerged from each die 42, 44, and 46.

[0095] Each station II to VII, except for the pilot hole punching station I, is provided with a pilot pin 84 that can enter the pilot hole P of the hoop material F, as shown in Figure 8A. Note that the pilot pin 84 provided at the adhesive application station IV is not shown in Figure 8B.

[0096] Each pilot pin 84 has an upper flange 84A, a straight shaft portion 84B, and a lower tapered shaft portion 84C in that order along the axial direction. Each pilot pin 84 is inserted into a mounting hole 86 formed in the upper holder 12 and slides vertically through through holes 88 formed in the backing plate 16 and punch plate 18, and through holes 90 formed in the stripper 28. In addition to the lower tapered shaft portion 84C, the lower side of the straight shaft portion 84B protrudes below the lower surface 33 of the stripper plate 32, which is in its lowest position relative to the upper holder.

[0097] With this setting, during the descent process of the upper holder 12, before the lower surface 33 of the stripper plate 32 contacts the hoop material F, the straight shaft portion 84B of each pilot pin 84 enters the corresponding pilot hole P, and positioning is performed on the upper surface 47 of the die plate 40 in a direction perpendicular to the forward feeding direction of the hoop material F, i.e., in the left-right direction.

[0098] Each pilot pin 84 is set to its lowest position (lowest limit position) when the lower surface of the upper end flange 84A abuts against the upper surface of the backing plate 16 which forms the bottom surface of the mounting hole 86, and is biased downward by the spring force of a compression coil spring 94 provided between the plug 92 fixed to the upper holder 12 to close the top of the mounting hole 86 and the upper end flange 84A. This spring biasing structure is a relief structure that prevents damage to the pilot pin 84 if the pilot pin 84 does not enter the pilot hole P correctly. A pin relief hole 41 into which the pilot pin 84 enters is formed in the die plate 40.

[0099] Next, the feed guide structure and lift-up structure for the hoop material F will be described with reference to Figures 4, 8A, and 8B. On the lower holder 14, and on the die plate 40 fixed to the lower holder 14 in the illustrated embodiment, left and right guide members 100 are symmetrically mounted on the die plate 40 which is fixed to the lower holder 14, to guide the movement of the hoop material F of the thin steel plate in the direction along the intermittent transport direction (forward feed direction) of the hoop material F. The left and right guide members 100 are each long strip-shaped in the direction of the forward feed of the hoop material F, and as shown in Figure 4, they are intermittently provided in the direction of the forward feed of the hoop material F, except for the areas corresponding to stations II, IV, and VI.

[0100] As shown in Figure 16, the left and right guide members 100 have a lower surface 102 with horizontal walls that face the upper surface 47 of the die plate 40 from above at a predetermined distance T, and side surfaces 103 with vertical walls that face the left and right end faces of the hoop material F at a predetermined gap, with the sides facing each other having a hook-shaped cross-section. The lower surface 102 and side surfaces 103 of the guide members 100 and the upper surface 47 of the die plate 40 cooperate with each other to define the left and right guide grooves 104 of the inner opening with a rectangular cross-section that extends in the forward feeding direction of the hoop material F.

[0101] As the left and right side edges of the hoop material F each fit into the left and right guide grooves 104, each guide member 100 restricts the lateral movement of the hoop material F with its side surface 103 and restricts the upward movement of the hoop material F with its bottom surface 102, thereby guiding the intermittent transport of the hoop material F.

[0102] This prevents the hoop material F from shifting left-right and up-down during intermittent transport, and also restricts the hoop material F from moving left-right and upward from the upper surface 47 of the die plate 40 when adhesive is applied to the adhesive application surface (bottom surface) of the hoop material F. This ensures that the adhesive is applied accurately to the adhesive application surface. Furthermore, the hoop material F is restricted (prevented) from moving downward by being placed on the upper surface 47 of the die plate 40, or by being lifted up by the lifter pin 110 described later.

[0103] The predetermined interval T mentioned above is greater than the sum of the amount L of the hoop material F lifted up by the lifter pin 110 (described later) and the thickness of the hoop material F. With this setting, even when the hoop material F is lifted up by the lifter pin 110, the hoop material F does not come into contact with the lower surface 102 of the guide member 100. As a result, the upper surface of the hoop material F does not slide against the lower surface 102 of the guide member 100 during intermittent transport of the hoop material F, and the guide member 100 does not increase the frictional resistance during intermittent transport of the hoop material F.

[0104] As shown in Figure 4, lifter pins 110 are provided on both the left and right sides of the die plate 40 at predetermined intervals in the forward feeding direction of the hoop material F. The positions of each lifter pin 110 coincide with the positions of each guide member 100 in a plan view.

[0105] Each lifter pin 110 is provided so as to be vertically displaceable in a lifter pin hole 112 formed in the die plate 40 and the lower holder 14, opening to the upper surface 47 of the die plate 40, as shown in Figures 8A and 8B, with its upper end exposed on the upper surface 47 of the die plate 40. A lifter spring 114, made of a compression coil spring, is provided between each lifter pin 110 and the bottom of each lifter pin hole 112. Each lifter spring 114 biases the corresponding lifter pin 110 upward.

[0106] Approximately half of the upper end surface of each lifter pin 110 abuts against the lower surface of the hoop material F, and the remaining half is capable of abutting against the stopper surface 106 formed on the guide member 100. As a result, as shown in Figures 8A, 8B, and 16, when the hoop material F is not being pushed down by the stripper 28, each lifter pin 110 is positioned in an elevated position where its upper end surface abuts against the stopper surface 106 due to the spring biasing force of the lifter spring 114, causing the hoop material F to float (lift up) above the upper surface 47 of the die plate 40. When the hoop material F is pushed down by the stripper 28, each lifter pin 110 descends against the spring force of each lifter spring 114 due to the hoop material F, as shown in Figures 11A, 11B, and 18, and the entire pin sinks into each lifter pin hole 112.

[0107] The amount L of the lift-up of the hoop material F by the lifter pin 110 is determined by the contact of the upper surface of the lifter pin 110 with the downward stopper surface 106 of the guide member 100, as shown in Figure 16. This lift-up amount L is set to a value greater than the thickness (maximum thickness) of the adhesive applied to the lower surface of the hoop material F.

[0108] Next, the operation of the manufacturing apparatus 10 with the above configuration will be explained with reference to Figures 8A, 8B to 15A, 15B, and 16 to 19. Figures 8A to 15A show the operation of the internal die-cutting station II as representative of each die-cutting station, and Figures 8B to 15B show the operation of the adhesive application station IV. The operation of the pilot hole die-cutting station I and the external die-cutting station VI is substantially the same as the operation of the internal die-cutting station II, so their operation will be omitted.

[0109] Figures 8A and 8B show the press start state, where the upper ram (not shown) of the press machine is at top dead center and the upper holder 12 is at its highest position (top dead center position). In this press start state, the internal punching punch 22, stripper 28, and pilot pin 84 are spaced apart above the die plate 40. The hoop material F is in a floating position (lifted up) separated from the upper surface 47 of the die plate 40 by the lifter pin 110 (see Figure 16). In the lifted up state, the hoop material F is intermittently transported in predetermined amounts in the forward direction by an intermittent feed device (not shown) without its lower surface sliding against the upper surface 47 of the die plate 40.

[0110] Once an intermittent transfer is completed, or during the intermittent transfer process, the upper holder 12 begins to descend from the top dead center position, as shown in Figures 9A and 9B. As the upper holder 12 descends, the straight shaft portion 84B of each pilot pin 84 enters the pilot hole P of the hoop material F, following the tapered shaft portion 84C of the lower end of each pilot pin 84, before the stripper 28 presses the hoop material F against the upper surface 47 of the die plate 40, as shown in Figures 10A and 10B. This positions the hoop material F in the transfer direction (forward feed direction) and left-right direction relative to the manufacturing apparatus 10.

[0111] Since this positioning is performed with the hoop material F lifted up from the upper surface 47 of the die plate 40, the movement of the hoop material F in the transfer direction and left-right direction relative to the manufacturing apparatus 10 for positioning is performed with low frictional resistance.

[0112] As the upper holder 12 descends further, the lower surface 33 of the stripper plate 32 comes into contact with the upper surface of the hoop material F, as shown in Figures 11A and 11B (see Figure 17), and the stripper 28, together with the lifter pin 110, pushes down the hoop material F against the upper surface 47 of the die plate 40, resisting the spring force of the lifter spring 114 (see Figure 18). At this time, the combined spring force setting of the stripper spring 29 and the lifter spring 114 prevents the stripper spring 29 from being compressed and deformed, and the stripper 28 maintains its lowest position relative to the upper holder 12.

[0113] As the upper holder 12 descends further, as shown in Figures 12A and 12B, the stripper spring 29 compresses and deforms as the upper holder 12 descends relative to the stripper 28, reaching a bottom dead center where the lower surface of the upper holder 12 contacts the upper surface of the stopper 82. As a result, in the internal die-cutting station II, as shown in Figure 12A, the internal die-cutting punch 22 enters the internal die-cutting die 44 with the hoop material F clamped against the upper surface 47 of the die plate 40 by the spring-biased stripper 28, and the internal die IS is cut. In addition, in the adhesive application station IV, when the hoop material F is pressed against the upper surface 47 of the die plate 40 by the spring-biased stripper 28, the raised portion N of the adhesive discharged from each discharge hole 64 is transferred to the corresponding application point E on the lower surface of the hoop material F (see Figure 7).

[0114] The transfer of this adhesive is performed with the lateral movement of the hoop material F restricted by the guide member 100 and the upward movement of the hoop material F restricted, and the positioning of the hoop material F is performed by the pilot pin 84. Therefore, even if the application points E are small, the transfer of the adhesive to each application point E is performed accurately with high positional precision.

[0115] Furthermore, since the adhesive transfer is performed when the lower surface of the hoop material F is pressed against the upper surface 47 of the die plate 40, and the hoop material F is unable to vibrate, even if the punching of the inner shape IS and the transfer of the adhesive are performed simultaneously, the transfer of the adhesive does not occur while the hoop material F is vibrating due to the punching impact at the inner shape punching station II, and the adhesive is accurately transferred to each application point E. This also ensures that even if the application points E are small, the adhesive is accurately transferred to each application point E with good positional accuracy.

[0116] Once the punching of the internal shape IS and the transfer of the adhesive are complete, the upper holder 12 begins to rise from the bottom dead center, as shown in Figures 13A and 13B. As the upper holder 12 rises from the bottom dead center, the internal shape punching punch 22 first exits the internal shape punching die 44 upward. As described above, the stroke by which the stripper 28 moves relative to the upper holder 12 is greater than the maximum entry stroke by which the internal shape punching punch 22 enters the internal shape punching die 44. Therefore, the hoop material F is kept pressed against the upper surface 47 of the die plate 40 by the stripper 28 until the internal shape punching punch 22 has exited the internal shape punching die 44.

[0117] As a result, even if vibration occurs due to friction when the internal die 44 and hoop material F are removed from the punched opening, the vibration is not transmitted to the hoop material F at the adhesive application station IV, and the transferred shape of the adhesive transferred to the application point E of the hoop material F is not disrupted or scattered.

[0118] As the upper holder 12 rises, the stripper 28 rises along with the upper holder 12, as shown in Figures 14A and 14B, and each lifter pin 110 rises due to the spring force of the lifter spring 114, lifting the hoop material F. As each lifter pin 110 comes into contact with the stopper surface 106, the hoop material F returns to a floating position (lifted up state) away from the upper surface 47 of the die plate 40.

[0119] As shown in Figure 19, the lifting of the hoop material F is performed with the guide member 100 preventing the hoop material F from shifting in the left-right direction, and with the stripper 28 in contact with the upper surface of the hoop material F and the lifter pin 110 in contact with the lower surface of the hoop material F, so that the hoop material F is supported from above and below by the stripper 28 and the lifter pin 110. This suppresses the swaying of the hoop material F during the lifting process. As a result, the transfer shape of the adhesive transferred to the application point E of the hoop material F is prevented from collapsing or scattering during the lifting process of the hoop material F.

[0120] As the upper holder 12 rises further, the pilot pin 84 exits the pilot hole P upward, as shown in Figures 15A and 15B, and then the upper holder 12 returns to the top dead center position shown in Figures 8A and 8B. Intermittent transfer of the hoop material F begins when the pilot pin 84 exits the pilot hole P. This intermittent transfer is performed with the hoop material F lifted up by the lifter pin 110 so that its lower surface is lifted up by a lift amount L (see Figure 16) away from the upper surface 47 of the die plate 40. Therefore, the adhesive transferred to the application point E on the lower surface of the hoop material F is not rubbed off by the upper surface 47 of the die plate 40.

[0121] This intermittent transfer is performed with the guide member 100 restricting the upward movement of the hoop material F and preventing it from shifting laterally. As a result, the transfer shape of the adhesive applied to the application point E of the hoop material F does not collapse or scatter during the transfer process. The intermittent transfer is completed before the next punching process begins.

[0122] As a result, the adhesive is applied accurately to the adhesive-coated surface of the iron core sheet W, and the adhesive applied to the adhesive-coated surface of the iron core sheet W does not diffuse into the surrounding area, causing the transferred shape to collapse or scatter. This enables the stable production of high-quality laminated iron cores, even in small sizes.

[0123] In another embodiment, as shown in Figure 20, the pilot hole P may be formed at a position corresponding to directly below the pilot pin guide hole 108 formed through the guide member 100. In this case, the pilot pin 84 can be inserted into the pilot hole P with high precision while suppressing the flapping of the hoop material F. Furthermore, since the pilot pin 84 (see Figure 8A) penetrates the pilot pin guide hole 108 and enters the pilot hole P, the positioning accuracy of the hoop material F by the pilot pin 84 is improved.

[0124] Next, other embodiments of the laminated iron core manufacturing apparatus 10 will be described with reference to Figures 21, 22A, and 22B. In Figures 21, 21A, and 21B, parts corresponding to Figures 4, 8A, and 8B are given the same reference numerals as those used in Figures 4, 8A, and 8B, and their descriptions are omitted.

[0125] In this embodiment, as shown in Figure 21, the guide member 100 is omitted, and the lifter pin 120 also serves as the guide member for the hoop material F. The lifter pins 120 are provided on both the left and right sides of the die plate 40, with lifter pins 110 each provided at predetermined intervals in the forward feeding direction of the hoop material F.

[0126] Each lifter pin 120 is provided so as to be vertically displaceable in a lifter pin hole 122 formed in the die plate 40 and the lower holder 14, opening onto the upper surface 47 of the die plate 40, as shown in Figures 22A and 22B, with its upper end protruding above the upper surface 47 of the die plate 40. A lifter spring 124, consisting of a compression coil spring, is provided between each lifter pin 120 and the bottom of each lifter pin hole 122. Each lifter spring 124 biases the corresponding lifter pin 110 upward. Each lifter pin 120 is positioned in an elevated position when the hoop material F is not being pushed down by the stripper 28, due to the spring biasing force of the lifter spring 124, so that the stepped portion 120A abuts against the shoulder portion 116 provided at the joint between the die plate 40 and the lower holder 14. When the hoop material F is being pushed down by the stripper 28, each lifter pin 120 is positioned in a lowered position, having been lowered by the hoop material F against the spring force of each lifter spring 114.

[0127] Each lifter pin 120 has a circumferential groove 126 on the outer circumference of the portion that protrudes above the upper surface 47 of the die plate 40. Each circumferential groove 126 has a rectangular cross-sectional shape, similar to the guide groove 104 in the above-described embodiment. The left and right side edges of the hoop material F fit into the circumferential groove 126, causing the hoop material F to float (lift up) above the upper surface 47 of the die plate 40 in the raised position, and to place the hoop material F on the upper surface 47 of the die plate 40 in the lowered position. Furthermore, the left and right side edges of the hoop material F fit into the circumferential grooves 126 of each of the left and right lifter pins 120, thereby restricting the lateral movement of the hoop material F and guiding the intermittent transport of the hoop material F. In addition to restricting the upward movement of the hoop material F during the lift-up position, the lifter pins 120 also restrict the downward movement of the hoop material F.

[0128] This restricts the lateral movement and upward and downward movement of the hoop material F during intermittent transport and adhesive application to the adhesive application surface. This restriction suppresses flapping of the hoop material F, ensuring accurate application of adhesive to the adhesive application surface.

[0129] This embodiment is substantially the same as the previously described embodiment except for the lift-up structure of the hoop material F by the lifter pin 120 described above, so the effects and advantages of the previously described embodiment can also be obtained in this embodiment.

[0130] In this embodiment, the lifter pin 120 also serves as a guide member for the hoop material F, thus reducing the number of parts.

[0131] Other embodiments of the laminated iron core manufacturing apparatus according to the present invention include the following:

[0132] (1) A manufacturing apparatus for laminated iron cores, comprising lamination and bonding of iron core sheets punched out into a predetermined shape from a strip of thin steel sheet, the apparatus comprising an upper holder and a lower holder, a plurality of punches and dies provided on the upper holder and the lower holder respectively for sequentially punching out iron core sheets from a strip of thin steel sheet that is intermittently transported, a pilot pin provided on the upper holder and fitted into a pilot hole formed in the strip of thin steel sheet to position the strip of thin steel sheet at each transport position, and an adhesive application device provided on at least one of the upper holder and the lower holder for applying adhesive to the adhesive application surface of the strip of thin steel sheet corresponding to the iron core sheet.

[0133] (2) A manufacturing apparatus for a laminated iron core, comprising lamination and bonding of iron core sheets punched out into a predetermined shape from a strip of thin steel sheet, the apparatus comprising an upper holder and a lower holder, a plurality of punches and dies provided on the upper holder and the lower holder respectively to sequentially punch out iron core sheets from a strip of thin steel sheet that is intermittently transported, a stripper plate provided on the upper holder so as to be displaceable in the vertical direction and having a lower surface facing the upper surface of the die, and an adhesive application device provided on at least one of the upper holder and the lower holder to apply adhesive to the adhesive application surface of the strip of thin steel sheet corresponding to the iron core sheet. In this case, the manufacturing apparatus for a laminated iron core further comprises a stripper spring that biases the stripper plate toward the lower holder, and the stripper plate may be configured such that its lower surface presses the strip of thin steel sheet toward the upper surface of the die by the spring force of the stripper spring. Furthermore, the stripper plate may be configured such that its lower surface presses the strip-shaped thin steel plate against the upper surface of the die until the punch disengages from the die.

[0134] (3) A manufacturing apparatus for laminated iron cores, comprising laminating and bonding iron core sheets punched out into a predetermined shape from a strip of thin steel sheet, the apparatus comprising an upper holder and a lower holder, a plurality of punches and dies provided on the upper holder and the lower holder respectively to sequentially punch out iron core sheets from a strip of thin steel sheet that is intermittently transported, a plurality of lifters provided on the lower holder so as to be displaceable in the vertical direction and to contact the lower surface of the strip of thin steel sheet to separate the strip of thin steel sheet from the upper surface of the die, and an adhesive application device provided on at least one of the upper holder and the lower holder to apply adhesive to the adhesive application surface of the strip of thin steel sheet corresponding to the iron core sheet. In this case, the device may further include a plurality of lifter springs that bias each lifter upward in order to separate the strip-shaped thin steel plate from the upper surface of the die, while the stripper plate and each lifter support the strip-shaped thin steel plate from above and below when the stripper plate rises.

[0135] Although the present invention has been described above in terms of preferred embodiments, as will be easily understood by those skilled in the art, the present invention is not limited to these embodiments and can be modified as appropriate without departing from the spirit of the invention.

[0136] For example, the adhesive application stand 60 (adhesive liquid 1) may not only be lowered during weighing, but may also repeatedly lower and raise in synchronization with the press operation. The curing accelerator or initiator (adhesive liquid 2) may be applied continuously, or only when the hoop material F is stopped. The curing accelerator or initiator (adhesive liquid 2) may be applied to the entire hoop material F, or only to a portion of it. In addition, multiple adhesive reservoirs 62 may be provided, and adhesive may be supplied from each adhesive reservoir 62 to the discharge holes 64 for each area. The supply of adhesive to the adhesive reservoirs 62 may be continuous, or intermittent in synchronization with the press operation. The application of adhesive is not limited to transfer, but may also be spray application using a jet method. The adhesive may be applied to the top surface or both the bottom and top surfaces of the hoop material F. The shape of the adhesive application is not limited to round dots, but may be annular, triangular, square, or other irregular shapes.

[0137] Depending on the type of laminated core, internal punching may not be necessary, in which case internal punching can be omitted. Also, the pilot pin 84 is not essential. In addition to annular and circular shapes, the planar shape of the laminated core can be square, T-shaped, U-shaped, etc.

[0138] It is not essential that the stripper plate 32 presses the hoop material F against the upper surfaces of the die plate 40, dies 44, 42, 46, and the coating table 60. The stripper plate 32 may simply restrict the vertical displacement of the hoop material F between the die plate 40, dies 44, 46, and the upper surfaces of the coating table 60 until the punches 22, 24 disengage from the dies 44, 46.

[0139] The stripper plate 32 and the lifter pin 110 may be arranged in a configuration that is offset from each other in the left-right direction and does not overlap in a plan view, or they may be arranged in a configuration that overlaps each other in a plan view in order to sandwich the hoop material F from above and below. The lifter pin 110 may also be positioned in the middle of the hoop material F in the left-right direction.

[0140] Adhesive application by the adhesive application device 50 is preferably performed immediately before the outer diameter punching process, considering that it shortens the transport distance of the hoop material F after adhesive application, but it is not necessarily required to be performed immediately before the outer diameter punching process. Heating and rotary lamination processes are not essential.

[0141] Furthermore, not all of the components shown in the above embodiments are necessarily essential, and they can be appropriately selected and omitted as long as they do not deviate from the spirit of the present invention. For example, the pilot pin, guide member, and stripper structure are not essential and may be omitted. [Explanation of symbols]

[0142] 10: Manufacturing equipment 12: Upper holder 13: Through hole 14: Lower holder 15: Spring chamber 16: Backing Plate 17: Plug 18: Punch Plate 20: Punch for punching pilot holes 22: Punch for punching out internal shapes 24: Punch for cutting out external shapes 26: Knockout 26A: Bottom end 26B: Upper flange 26C: Shaft 28: Stripper 29: Spring for stripper 30: Stripper body 32: Stripper Plate 33: Bottom surface 34: Punch insertion hole 36: Punch insertion hole 38: Punch insertion hole 40: Die plate 41: Pin escape hole 42: Die for punching pilot holes 44: Die for punching out internal shapes 46: Die for punching out external shapes 47:Top surface 48: Discharge hole 50: Adhesive application device 52: Cam mechanism 54: Drive unit 56: Holding hole 58: Upper block 59: Lower block 60: Application stand 61:Top surface 62: Adhesive accumulation area 64:Discharge hole 66: Internal Block 68: Adhesive supply channel 70: Adhesive supply tube 72: Adhesive supply device 74: Fixed cam 74A: Sawtooth Mountains 74B: Sawtooth Valley 76: Mobile Camera 76A: Sawtooth Mountain Section 76B: Sawtooth Valley 82: Stopper 84: Pilot pin 84A: Upper flange 84B: Straight shaft section 84C: Lower end tapered shaft section 86: Mounting hole 88: Through hole 90: Through hole 92: Plug 94: Compression coil spring 100: Guide member 102: Bottom surface 103: Side view 104: Guide groove 106: Stopper surface 108: Pilot pin guide hole 110: Lifter pin 112: Lifter pin hole 114: Spring for lifter 116:Shoulder 120: Lifter pin 120A: Stepped section 122: Lifter pin hole 124: Spring for lifter 126: Peripheral groove I: Pilot hole punching station II: Internal die-cutting station III: Idol Station IV: Adhesive application station V: Idol Station VI: Outer shape punching station VII: Idol Station T: Predetermined interval L: Lift-up amount A: Thin iron core W: Thin iron core M: Laminated iron core F: Hoop material (thin strip steel sheet) E: Application point E1: Application point E2: Application point G: Iron core thin sheet group

Claims

1. A manufacturing apparatus for laminated iron cores, which involves laminating and bonding iron core thin sheets that are punched into a predetermined shape from intermittently transported strip-shaped thin steel sheets, Upper holder and lower holder, A plurality of punching stations each include a punch attached to the upper holder and a die attached to the lower holder, and each punches out shapes corresponding to each punching operation in order to punch out the intermittently transported strip of thin steel sheet into a predetermined shape, An adhesive application station includes an adhesive application device provided on at least one of the upper holder and the lower holder, which applies adhesive to the adhesive application surface of the portion of the strip-shaped thin steel sheet corresponding to the iron core sheet that is intermittently transported, Multiple guide members are provided on the lower holder to guide the intermittent transfer of the strip-shaped thin steel plate and to restrict the upward movement of the strip-shaped thin steel plate, It has, Each of the aforementioned plurality of guide members is a strip-shaped member that is long in the direction of the intermittent transfer of the strip-shaped thin steel plate, and includes multiple pairs of left and right guide members. A laminated steel core manufacturing apparatus, wherein two of the multiple pairs of left and right guide members, corresponding to the adhesive application station, are positioned upstream and downstream of the region corresponding to the adhesive application station in the intermittent transfer direction of the strip-shaped thin steel plate, so as to sandwich the region excluding that region.

2. The die plate provided on the lower holder, A stripper plate is provided on the upper holder so as to be displaceable in the vertical direction and has a lower surface facing the upper surface of the die plate, and presses the strip-shaped thin steel plate, which is in the adhesive application position by the adhesive application device, against the upper surface of the die plate, A manufacturing apparatus for laminated iron cores according to claim 1, having the following features.

3. The apparatus for manufacturing a laminated iron core according to claim 1 or claim 2, further comprising an apparatus for applying a hardening accelerator for the adhesive to the upper surface of the strip-shaped thin steel plate.

4. The apparatus for applying the hardening accelerator is a apparatus for manufacturing a laminated iron core according to claim 3, wherein the apparatus for applying the hardening accelerator is a apparatus for continuously applying the hardening accelerator to the strip-shaped thin steel sheet.

5. The apparatus for applying the hardening accelerator is configured to apply the hardening accelerator to the strip of thin steel sheet only when the strip of thin steel sheet is stopped during the intermittent transfer, as described in claim 3.

6. A method for manufacturing a laminated iron core, comprising laminating and bonding iron core thin sheets that have been punched out into a predetermined shape from a strip of thin steel sheet using a press device having an upper holder and a lower holder, A transfer process in which the strip of thin steel sheet is intermittently transferred while the upward movement of the strip of thin steel sheet is restricted by a plurality of guide members provided on the lower holder and the transfer of the strip of thin steel sheet is guided along the intermittent transfer direction of the strip of thin steel sheet, The process involves a punching step in which the outer shape of the iron core thin sheet is punched out by the punch and die provided on the upper holder and the lower holder as the upper holder is lowered, The process includes, before the punching step, an adhesive application step in which an adhesive is applied to the adhesive application surface of the strip-shaped thin steel sheet using an adhesive application device provided on at least one of the upper holder and the lower holder, Each of the aforementioned plurality of guide members is a strip-shaped member that is long in the direction of the intermittent transfer of the strip-shaped thin steel plate, and includes multiple pairs of left and right guide members. Of the multiple pairs of left and right guide members, two pairs provided corresponding to the adhesive application station where the adhesive application process is carried out are arranged on the upstream and downstream sides of the region corresponding to the adhesive application station in the intermittent transport direction of the strip-shaped thin steel plate, respectively, so as to sandwich the region excluding that region. A method for manufacturing a laminated steel core, wherein, in the adhesive application step, the movement of the strip-shaped thin steel plate in the left-right direction and upward is restricted by the pair of left and right guide members.

7. The method for manufacturing a laminated iron core according to claim 6, further comprising a curing accelerator application step of applying the curing accelerator for the adhesive to the upper surface of the strip-shaped thin steel plate.

8. The method for manufacturing a laminated iron core according to claim 7, wherein in the step of applying the hardening accelerator, the hardening accelerator is continuously applied to the strip-shaped thin steel sheet.

9. The method for manufacturing a laminated iron core according to claim 7, wherein in the hardening accelerator application step, the hardening accelerator is applied to the strip-shaped thin steel sheet only when the strip-shaped thin steel sheet is stopped during the intermittent transfer.

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