Progressive die device and method for manufacturing iron core thin plate

Abstract

[Problem] To increase the degree of freedom of the arrangement position of a pilot pin. [Solution] A plurality of pilot holes P are punched for each transfer of a band-shaped thin plate F in intermittent transfer, and a pilot pin 80 is arranged so as to use one of the plurality of pilot holes P in a given processing stage. In one of the other processing stages, the pilot pin 80 is arranged so as to use a pilot hole other than said pilot hole among the plurality of pilot holes P.

Description

Progressive die device and method for manufacturing thin iron core plates

[0001] The present invention relates to a progressive die device for manufacturing thin iron core plates and a method for manufacturing thin iron core plates.

[0002] [Correction pursuant to Rule 91, 26.01.2024] Progressive dies are commonly used to manufacture laminated cores (thin core sheets) for motor cores and other applications. Progressive dies have multiple processing stages in which necessary processing steps are sequentially performed on a strip of thin sheet metal (hoop material). Each processing stage involves punching pilot holes (positioning holes), punching internal shapes (internal shapes such as slots and teeth), forming crimped portions, and applying adhesive, as needed. As a result, the strip of thin sheet metal is transported through the progressive die, and the shapes of each thin sheet metal that constitutes the laminated core are continuously formed. Finally, the outer shapes of the thin core sheets are punched out of the strip of thin sheet metal, and the required number of thin core sheets are stacked and fixed together in the progressive die to complete the laminated core.

[0003] In the manufacture of iron core sheets using a progressive die, a strip of sheet metal is intermittently transferred at a predetermined pitch (hereinafter referred to as the transfer pitch), and pilot pins are engaged with pilot holes formed in the strip of sheet metal to position the strip of sheet metal relative to the progressive die, and while in this position, predetermined processes such as inner and outer shape punching are performed in each processing stage (see, for example, Patent Documents 1 and 2). The progressive die may be provided with movable parts such as a plate cam or a rotary die that changes the effective length of the punch used for crimping for measurement.

[0004] As the first step in the manufacture of iron core thin plates using a progressive die, one pilot hole is drilled on each side edge of the strip thin plate each time the strip thin plate is transferred during intermittent transfer. In this drilling, the pilot holes are aligned in the transfer direction along each side edge of the strip thin plate at intervals equal to the transfer pitch.

[0005] JP 2015-5649 A JP 2021-93908 A

[0006] The pilot holes are spaced at the same interval as the transfer pitch of the strip, leaving little flexibility in their placement. The pilot pins that engage with the pilot holes also have little flexibility in their placement. Therefore, even if the placement positions of the pilot pins are changed as much as possible, it may not be possible to avoid interference between the pilot pins and moving parts such as the plate cam and the rotary die. Avoiding such interference requires the structure of the moving parts to be made more complex, which reduces the strength of the parts and reduces workability and maintainability.

[0007] In view of the above background, an object of the present invention is to increase the degree of freedom in the arrangement position of a pilot pin.

[0008] In order to solve the above problem, one aspect of the present invention is a progressive die device that performs a predetermined processing on a strip-shaped thin plate that is intermittently transported at a predetermined pitch in each of a plurality of processing stages aligned in the transport direction of the strip-shaped thin plate, to produce iron core thin plates of a predetermined shape, the device having a pilot hole forming section that punches out and forms a plurality of pilot holes for each transfer of the strip-shaped thin plate during intermittent transport, and at least one pilot pin that is provided corresponding to each of the processing stages and engages with the corresponding pilot hole to position the strip-shaped thin plate in each processing stage, wherein in one of the processing stages, the pilot pin is positioned so as to engage with one of the plurality of pilot holes, and in another of the processing stages, the pilot pin is positioned so as to engage with one of the plurality of pilot holes other than the one.

[0009] According to this aspect, the degree of freedom in the positioning of the pilot hole with which the pilot pin engages is increased, and therefore the degree of freedom in the positioning of the pilot pin is increased.

[0010] In the above aspect, the pilot hole forming section may be configured so that the plurality of pilot holes are aligned in the transfer direction.

[0011] According to this aspect, the degree of freedom in the position of the pilot pin is increased in relation to the direction of transfer of the strip-shaped thin plate.

[0012] In the above aspect, the pilot hole forming section may be configured so that the plurality of pilot holes are aligned along each of the opposite side edges of the belt-shaped thin plate in the transfer direction.

[0013] According to this aspect, the degree of freedom in the arrangement position of the pilot pin is increased in the transfer direction of the strip-shaped thin plate at the positions corresponding to the side edges of the strip-shaped thin plate.

[0014] In the above aspect, a processing element that performs a predetermined processing on the strip-shaped thin plate is installed on each of the processing stages, and the pilot pin engages with one of the multiple pilot holes formed at multiple locations on each of the processing stages, spaced apart from the processing element in the transport direction, that does not interfere with the processing element.

[0015] According to this aspect, the degree of freedom in the position of the pilot pin is increased in relation to the direction of transfer of the strip-shaped thin plate.

[0016] In the above aspect, one of the processing stages includes a crimping portion forming stage equipped with a crimping portion forming punch and a crimping portion forming die that form a crimping portion in the strip-shaped thin plate, and a cam that increases or decreases the effective length of the crimping portion forming punch, and the processing member that is subject to interference with the pilot pin is the cam.

[0017] According to this aspect, interference between the pilot pin and the cam is avoided.

[0018] In the above aspect, one of the processing stages is an adhesive application stage equipped with an adhesive application device that applies adhesive to the strip-shaped thin plate, and the processing member that is subject to interference with the pilot pin is the adhesive application device.

[0019] According to this aspect, it is possible to prevent the pilot pin from interfering with the adhesive applicator.

[0020] In the above aspect, one of the processing stages includes a punching stage equipped with a punch and a rotary die, and the processing member that is subject to interference with the pilot pin is the rotary die.

[0021] According to this aspect, interference between the pilot pin and the rotary die is avoided.

[0022] In order to solve the above problem, one aspect of the present invention is a manufacturing method for producing iron core thin plates of a predetermined shape by performing a predetermined processing on a strip-shaped thin plate that is intermittently transported at a predetermined pitch in each of a plurality of processing stages set up in alignment in the transport direction of the strip-shaped thin plate by a progressive die device, wherein, with each intermittent transport, a plurality of pilot holes are punched out and formed by a pilot hole forming section, and at least one pilot pin provided corresponding to each of the processing stages engages with the corresponding pilot hole to position the strip-shaped thin plate in each processing stage, and one of the processing stages uses one of the plurality of pilot holes, and another of the processing stages uses one of the plurality of pilot holes other than the one.

[0023] According to this aspect, the degree of freedom in the positioning of the pilot hole with which the pilot pin engages is increased, and therefore the degree of freedom in the positioning of the pilot pin is increased.

[0024] In the above aspect, the plurality of pilot holes may be aligned in the transfer direction.

[0025] According to this aspect, the degree of freedom in the position of the pilot pin is increased in relation to the direction of transfer of the strip-shaped thin plate.

[0026] According to the above aspect, the degree of freedom in the arrangement position of the pilot pin is increased.

[0027] FIG. 3 is a cross-sectional view of the progressive die device of the first embodiment; FIG. 4 is a cross-sectional view of the progressive die device of the first embodiment; FIG. 5 is a cross-sectional view of the progressive die device of the first embodiment; FIG. 6 is a cross-sectional view of the progressive die device of the first embodiment; FIG. 7 is a cross-sectional view of the progressive die device of the second embodiment;

[0028] Hereinafter, an embodiment of the progressive die device and the manufacturing method of the iron core thin plate according to the present invention will be described with reference to the drawings. For the sake of convenience, directions are defined by the arrows in each drawing, indicating up and down, front and rear, and left and right. However, the progressive die according to the present invention and the manufacturing method using the same are not necessarily limited by these directions.

[0029] First Embodiment A first embodiment will be described with reference to FIGS.

[0030] First, a specific example of a core sheet A used in a laminated core will be described with reference to Figure 1. The core sheet A is a press-formed product obtained by punching a strip-shaped sheet (hoop material) F (see Figure 2) into a predetermined shape using a progressive die device 10, which will be described next. The core sheets A are stacked, and in the first embodiment, adjacent sheets are joined together by crimping.

[0031] The core thin plate A has an annular yoke portion B, a plurality of teeth (magnetic pole portions) C extending radially inward from the yoke portion B, and a plurality of crimped portions D formed on the yoke portion B.

[0032] [Correction based on Rule 91 26.01.2024] The manufacturing process of the iron core thin plate A, as shown in Figure 2, involves sequentially carrying out the following steps under the condition that the strip-shaped thin plate F is intermittently transferred at a predetermined pitch T (hereinafter referred to as the transfer pitch T) with each press operation of the progressive die device 10: a pilot hole punching process (I) for punching and forming pilot holes P; a slot punching process (II) for punching and forming slots S between adjacent teeth C; a crimping portion forming process (III) for embossing each crimping portion D; an inner shape punching process (IV) for punching circular inner shapes G to define the tips of the teeth C; and an outer shape punching process (V) for punching and forming the circular outer shape H of the yoke portion B.

[0033] Next, the progressive die device 10 of the first embodiment will be described with reference to Fig. 3. The progressive die device 10 includes an upper die 20 and a lower die 60 arranged to sandwich the strip-shaped thin plate F therebetween.

[0034] The upper die 20 has a plate-shaped upper holder 22 fixed to the underside of the upper ram (not shown) of the press machine. This allows the upper die 20 to move up and down so as to approach and move away from the lower die 60. In the upper die 20, a backing plate 24 and a punch plate 26 are attached to the lower part of the upper holder 22. The punch plate 26 fixes a pilot hole punch 28, a slot punch 30, a crimping portion-forming punch 32, an inner shape punching punch 34, and an outer shape punch 36 to the upper holder 22. The backing plate 24 prevents the processing forces of the punches 28, 30, 32, 34, and 36 from being directly applied to the upper holder 22. A plate cam 38 for metering control, which increases and decreases the effective length of the crimping portion-forming punch 32, is attached to the backing plate 24 at a position corresponding to the crimping portion-forming punch 32 and is movable left and right.

[0035] In the upper mold 20, a stripper 40 is attached below the upper holder 22. The stripper 40 is movable in the vertical direction relative to the upper holder 22. The stripper 40 is suspended by a suspension bolt (not shown) and is set at its lowest position relative to the upper holder 22. The stripper 40 is configured as a joined body of a stripper body 40A and a stripper body 40B, each of which has a plate shape.

[0036] The lower surface of the stripper 40 faces the upper surfaces of a die plate 64 (described later) and the dies 68, 70, 72, 74, and 76. The stripper 40 has punch through-holes 42, 44, 46, 48, and 50 through which the punches 28, 30, 32, 34, and 36 pass.

[0037] The lower die 60 has a plate-shaped lower holder 62 fixed to the upper surface of the lower bolster (not shown) of the press machine. The lower holder 62 is positioned opposite the upper holder 22. In the lower die 60, a plate-shaped die plate 64 is attached to the upper surface of the lower holder 62. Attached to the die plate 64 are a pilot hole punching die 68, a slot punching die 70, a crimping portion forming die 72, an inner shape punching die 74, and an outer shape punching die 76. The outer shape punching die 76 is cylindrical and constitutes a rotary die that is divided and rotated around its own central axis at a predetermined rotation angle. The crimping portion forming punch 32, the plate cam 38, and the slot punching die 70 constitute a crimping portion forming member.

[0038] The punches 28, 30, 32, 34, 36 and the dies 68, 70, 72, 74, 76 correspond to each other and constitute individual processing stages spaced apart from one another in the direction of transport of the strip-shaped thin sheet F. As processing stages, the pilot hole punching punch 28 and the pilot hole punching die 68 constitute a pilot hole punching stage (pilot hole forming section) I, the slot punch 30 and the slot punching die 70 constitute a slot punching stage II, the crimping portion forming punch 32 and the crimping portion forming die 72 constitute a crimping portion forming stage III, the inner shape punching punch 34 and the inner shape punching die 74 constitute an inner shape punching stage IV, and the outer shape punching punch 36 and the outer shape punching die 76 constitute an outer shape punching stage V.

[0039] The slot punching stage II, the crimping portion forming stage III, the inner shape punching stage IV, and the outer shape punching stage V are each processing stages that perform a predetermined process in the progressive die device 10. The punches 28, 30, 32, 34, 36, the dies 68, 70, 72, 74, 76, and the plate cam 38 provided in each of the stages II to V constitute processing members that perform a predetermined process on the strip-shaped thin sheet F in each of the above-mentioned processing stages. In this way, processing members that perform a predetermined process on the strip-shaped thin sheet F are installed in each processing stage.

[0040] In other words, as processing members, the pilot hole punching stage I is equipped with a pilot hole punching punch 28 and a pilot hole punching die 68, the slot punching stage II is equipped with a slot punching punch 30 and a slot punching die 70, a crimping portion forming punch 32, a crimping portion forming die 72 and a plate cam 38, the inner shape punching stage IV is equipped with an inner shape punching punch 34 and an inner shape punching die 74, and the outer shape punching stage V is equipped with an outer shape punching punch 36 and an outer shape punching die 76.

[0041] The progressive die device 10 has an intermediate idle stage I1 between the inner punching stage IV and the outer punching stage V, and a final idle stage I2 on the forward side (downstream side) of the outer punching stage V in the transfer direction. In each of the idle stages I1 and I2, the strip-shaped thin plate F is fed empty.

[0042] As a result, the progressive die device 10 is configured with a pilot hole punching stage I, a slot punching stage II, a crimping portion forming stage III, an inner shape punching stage IV, an intermediate idle stage I1, an outer shape punching stage V, and a final idle stage I2, which are arranged in this order at predetermined intervals in the transport direction of the strip-shaped sheet metal F. The interval between the pilot hole punching stage I and the slot punching stage II is set to 1.5 times the transport pitch T of the strip-shaped sheet metal F, and the interval between adjacent stages is set to a value equal to the transport pitch T of the strip-shaped sheet metal F.

[0043] [Amendment based on Rule 91 26.01.2024] In the pilot hole punching stage I, the pilot hole punching process is carried out using a plurality of pilot hole punching punches 28 and a plurality of pilot hole punching dies 68 corresponding to each pilot hole punching punch 28, and a plurality of circular pilot holes P are punched in the strip sheet F with each press operation, i.e., with each intermittent transfer of the strip sheet F. The pilot holes P are formed along the vicinity of each of the left and right side edges of the strip sheet F, aligned in the transfer direction of the strip sheet F (see FIG. 2).

[0044] In the slot punching stage II, a slot punching process is carried out using a slot punching punch 30 and a slot punching die 70, and a slot S (see FIG. 2) is punched in the strip-shaped sheet F with each press operation. The slots S are arranged at predetermined intervals in the circumferential direction and correspond to the regions between the multiple tooth portions C formed in the strip-shaped sheet F. The slot punching punch 30 and the slot punching die 70 are provided corresponding to each slot S.

[0045] In the crimping portion forming stage III, the crimping portion forming step is carried out using the crimping portion forming punch 32 and the crimping portion forming die 72, and with each press operation, crimping portions D (see FIG. 2) are embossed into the strip-shaped thin plate F. The crimping portions D are arranged at predetermined intervals in the circumferential direction of the yoke portion B. Each crimping portion D has a convex shape on one side of the strip-shaped thin plate F and a concave shape on the opposite side, and in the outline punching stage V described below, adjacent stacked iron core thin plates A are crimped to join them.

[0046] A laminated core is made up of a predetermined number of core thin plates A crimped together. When more than the predetermined number of core thin plates A are manufactured using the progressive die device 10, the plate cam 38 moves in a direction increasing the effective length of the crimp portion-forming punch 32 each time the predetermined number of core thin plates A are manufactured. In other words, when measuring to set the number of laminated core thin plates A, the plate cam 38 moves in a direction increasing the effective length of the crimp portion-forming punch 32, and the effective length of the crimp portion-forming punch 32 increases due to the punching process.

[0047] In this state, the crimping portion forming punch 32 and the crimping portion forming die 72 form through holes instead of embossing in the core thin plates A. As a result, the core thin plates A that are stacked in the outline punching stage V, which will be described later, are not crimped together, and a laminated core in which a predetermined number of core thin plates A are crimped together is continuously manufactured.

[0048] In the inner shape punching stage IV, the inner shape punching step is carried out using the inner shape punching punch 34 and the inner shape punching die 74, and with each press operation, a circular inner shape G (see FIG. 2) is punched out of the strip-shaped thin plate F. As a result, with each press operation, a plurality of teeth C (including portions that define the inner edge) are punched out of the strip-shaped thin plate F.

[0049] In the outer shape punching stage V, an outer shape punching step is carried out by the outer shape punching punch 36 and the outer shape punching die 76, and with each press operation, a circular outer shape H (see FIG. 2) is punched out of the strip-shaped thin plate F. In this way, one iron core thin plate A is punched out of the strip-shaped thin plate F.

[0050] The core thin plates A completed by punching out the outer shape H are pushed into the outer shape punching die 76 by the outer shape punching punch 36, and are stacked in order on top of the previously punched core thin plates A inside the outer shape punching die 76. The multiple core thin plates A stacked inside the outer shape punching die 76 are joined to one another by crimping portions D.

[0051] In the outline punching stage V, when the upper die 20 descends to start punching the outline H, the stripper 40 descends together with the upper die 20. At this time, the strip-shaped sheet F is essentially stopped when not being conveyed (including cases where it is not strictly stopped). The descending stripper 40 presses the upper surface of the strip-shaped sheet F downward with its lower surface. At this time, the strip-shaped sheet F is sandwiched between the lower surface of the stripper 40 and the upper surface of the lower die 60.

[0052] When the upper die 20 rises after punching out the outer shape H, the stripper 40 rises together with the upper die 20. As a result, the stripper 40 is released from pressing the strip-shaped sheet F, and the strip-shaped sheet F is separated from the upper surface of the lower die 60. In this state, the strip-shaped sheet F is transported a predetermined feed amount in the forward feed direction.

[0053] The operation of the stripper 40 is the same in the other stages IV.

[0054] 4, pilot pins 80 are attached to the upper mold 20 at each of the stages II to V, I1, and I2 after stage I. Each pilot pin 80 engages with a corresponding pilot hole P at each of the stages II to V, I1, and I2 to position the belt-shaped thin plate F at each of the stages II to V, I1, and I2.

[0055] 4, a pilot pin 80 is attached to the punch plate 26 for each of the stages I to V, I1, and I2 in a state where it is spring-biased downward by a compression coil spring 82. The pilot pins 80 are provided near the left and right side edges Fa, Fb of the belt-shaped thin plate F. The pilot pins 80 on both the left and right sides of the punch plate 26 corresponding to the pilot holes P pass through pin through holes 84 formed in the stripper 40 and are exposed toward the upper surface of the die plate 64.

[0056] As the upper die 20 descends, the pilot pin 80 passes through the pilot hole P in the strip-shaped sheet F and engages with a pilot pin receiving hole 86 formed in the die plate 64. This engagement positions the strip-shaped sheet F relative to the progressive die device 10.

[0057] Next, the formation of the plurality of pilot holes P in the pilot hole punching stage I and the arrangement of the pilot pins 80 in each of the stages II to V, I1, and I2 after stage I will be described.

[0058] [Correction based on Rule 91 26.01.2024] As shown in Figure 2, the pilot hole punching punches 28 and pilot hole punching dies 68 in the pilot hole punching stage I are provided in pairs, aligned in the direction of transport of the strip of sheet metal F, at positions corresponding to the vicinity of each of the left and right side edges Fa, Fb of the strip of sheet metal F.

[0059] 2, two pilot holes P are formed near each side edge Fa, Fb of the strip sheet F, aligned in the direction of transport of the strip sheet F, for each transport of the strip sheet F. For convenience of explanation, the pilot hole P on the leading side (advancing side) of the two pilot holes P in the transport direction may be referred to as the leading pilot hole Pa, and the pilot hole P on the trailing side (lagging side) of the two pilot holes P in the transport direction may be referred to as the trailing pilot hole Pb.

[0060] The front pilot hole Pa and the rear pilot hole Pb are pilot holes formed for each transfer, and the front pilot holes Pa and the rear pilot holes Pb in the same row are formed at a predetermined interval that is smaller than the transfer pitch T in the transfer direction of the strip-shaped thin plate F. Pairs of the front pilot hole Pa and the rear pilot hole Pb are provided in each of stages II to V, in front of and behind the position of the processing member described above in each of stages II to V. That is, pairs of the front pilot hole Pa and the rear pilot hole Pb are formed in two locations in each of stages II to V, separated from the processing member described above in each of stages II to V in the transfer direction of the strip-shaped thin plate F. The pair of the front pilot hole Pa and the rear pilot hole Pb in front of the position of the processing member is called the front pair, and the pair of the front pilot hole Pa and the rear pilot hole Pb behind the position of the processing member is called the rear pair.

[0061] In one of stages II to V, the pilot pin 80 is arranged to use the front pilot hole Pa of the two pilot holes P, and in another of stages II to V, the pilot pin 80 is arranged to use the rear pilot hole Pb of the two pilot holes P. That is, in one of stages II to V, the pilot pin 80 is arranged to engage with one of the two pilot holes P, and in another of stages II to V, the pilot pin 80 is arranged to engage with one of the two pilot holes P other than the one mentioned above. As a result, in at least one of stages II to V, there is at least one pilot hole P that does not engage with the pilot pin 80.

[0062] This specific example will be described using the strip layout (single row) in Fig. 2. In Fig. 2, the pilot holes P with which the pilot pins 80 engage are indicated by circles with cross marks, and unused pilot holes P with which the pilot pins 80 do not engage are indicated by hollow circles.

[0063] In slot punching stage II, in both the front pair and the rear pair, the pilot pins 80 engage with the rear pilot holes Pb, but do not engage with the front pilot holes Pa. In other words, the front pilot holes Pa are unused.

[0064] From the viewpoint of performing slot punching with high precision, it is preferable that the pilot pin 80 engages with the pilot hole P formed at a position closest to the processing members (the slot punch 30 and the slot punch die 70) without interfering with the processing members. From this viewpoint, it is preferable that in the slot punching stage II, the pilot pin 80 engages with the rear pilot hole Pb in the front pair, and the pilot pin 80 engages with the front pilot hole Pa in the rear pair.

[0065] As an exception, the pilot hole P with which the pilot pin 80 engages immediately after the formation of the pilot hole P is preferably closer to the pilot hole punching stage I, so in this embodiment, in the rear pair in the slot punching stage II, which is the stage next to the pilot hole punching stage I, the pilot pin 80 engages with the rear pilot hole Pb, which is closer to the pilot hole punching stage I than the front pilot hole Pa.

[0066] In the crimping portion forming stage III, the pilot pin 80 engages with a pilot hole located away from the plate cam 38 (processing member) so as not to interfere with the plate cam 38, i.e., the pilot pin 80 engages with the front pilot hole Pa in the front pair, and the pilot pin 80 engages with the rear pilot hole Pb in the rear pair.

[0067] In the internal shape punching stage IV, in order to perform highly accurate internal shape punching, the pilot pin 80 engages with the pilot holes located close to the processing members (the internal shape punching punch 34 and the internal shape punching die 74), that is, in the front pair, the pilot pin 80 engages with the rear pilot hole Pb, and in the rear pair, the pilot pin 80 engages with the front pilot hole Pa.

[0068] In the contour punching stage V, so that the pilot pin 80 does not interfere with the contour punching die 76 (processing member), which is a rotary die, the pilot pin 80 engages with a pilot hole located away from the contour punching die 76, that is, the front pilot hole Pa in the front pair, and the rear pilot hole Pb in the rear pair.

[0069] In the intermediate idle stage I1, the pilot pin 80 engages with the rear pilot hole Pb in both the front pair and the rear pair. In the final idle stage I2, the pilot pin 80 engages with the rear pilot hole Pb in the front pair, and the pilot pin 80 engages with the front pilot hole Pa in the rear pair in the final idle stage I2.

[0070] At each stage, the pilot pin 80 is positioned so that it engages with the front pilot hole Pa or rear pilot hole Pb described above, thereby increasing the degree of freedom in the positioning of the pilot hole P with which the pilot pin 80 engages in relation to the transport direction of the strip-shaped thin plate F, and as a result, increasing the degree of freedom in the positioning of the pilot pin 80 in relation to the transport direction of the strip-shaped thin plate F.

[0071] This allows the pilot pin 80 to be easily positioned at a position where it does not interfere with the plate cam 38 or the outer shape punching die 76, which is a rotary die.

[0072] In other words, even if one of the front pilot hole Pa and the rear pilot hole Pb is formed in a position where it interferes with a processing member of a certain processing stage, such as the plate cam 38 or the contour punching die 76, the pilot pin 80 does not engage with the front pilot hole Pa or the rear pilot hole Pb that is in the interfering position, and the pilot pin 80 engages with the other front pilot hole Pa or the rear pilot hole Pb that is formed in a non-interfering position, so that the role of the pilot hole P is fulfilled in each processing stage without complicating the structure of the plate cam 38 or the contour punching die 76.

[0073] As a result, the strip-shaped thin plate F is properly positioned relative to the progressive die device 10 based on the engagement of the pilot hole P with the pilot pin 80, and high-precision iron core thin plates A can be repeatedly manufactured.

[0074] Figure 5 shows a strip layout for two rows. In two rows, the processing stages shown in Figure 2 are arranged in two rows, left and right. In each stage of the left and right rows, the front pilot holes Pa or rear pilot holes Pb used are biased in the transfer direction, depending on whether they are located on the left side edge Fa or the right side edge Fb of the strip-shaped thin sheet F. Note that in Figure 5 as well, pilot holes that are used when the pilot pins 80 engage are indicated by circles with cross marks, and unused pilot holes that are not engaged by the pilot pins 80 are indicated by hollow circles.

[0075] Therefore, in the case of two rows, as in the case of one row, the pilot pins 80 of each stage are arranged so as to engage with the front pilot holes Pa or rear pilot holes Pb described above in each stage.

[0076] This increases the degree of freedom in the positioning of the pilot holes P with which the pilot pins 80 engage in relation to the transport direction of the strip-shaped thin plate F, even in the case of two-row cutting.

[0077] Second Embodiment A second embodiment will be described with reference to Figures 6 and 7. In the second embodiment, parts that are substantially the same as those in the first embodiment will be denoted by the same reference numerals as those in the first embodiment.

[0078] In embodiment 2, the stacked core thin plates A are joined by adhesive. The core thin plates A used in embodiment 2 do not have the crimped portions D of embodiment 1, and the portions corresponding to the crimped portions D become bonding points J (see FIG. 6). The core thin plates A of embodiment 2 differ from embodiment 1 in the crimped portions D and bonding points J, but other configurations are the same as the core thin plates A of embodiment 1 shown in FIG. 1, so for convenience, they will be described using the same reference numerals as the core thin plates A of embodiment 1.

[0079] [Correction based on Rule 91 26.01.2024] The manufacturing process of the iron core thin plate A, as shown in Figure 6, involves the following steps being carried out in sequence: a pilot hole punching process (I) for punching out pilot holes P; a slot punching process (II) for punching out slots S between adjacent teeth C; an inner shape punching process (III) for punching out circular inner shapes G to define the tips of the teeth C; an adhesive application process (IV) for applying adhesive to each bonding point J of the strip-shaped thin plate F (yoke portion B); and an outer shape punching process (V) for punching out the circular outer shape H of the yoke portion B, while the strip-shaped thin plate F is intermittently transferred at a predetermined pitch T (hereinafter referred to as the transfer pitch T) with each press operation of the progressive die device 10.

[0080] In this embodiment, each adhesive point J is provided on the underside of the strip-shaped sheet F because an adhesive application device 90, which will be described later, is disposed below the strip-shaped sheet F. For this reason, each adhesive point J should be indicated by a hidden line (broken line) in Figure 6 (top view), but is indicated by black paint to make it easier to see the positions where adhesive has been applied.

[0081] Next, the progressive die device 10 of the first embodiment will be described with reference to Fig. 7. The progressive die device 10 includes an upper die 20 and a lower die 60 arranged to sandwich the strip-shaped thin plate F therebetween.

[0082] The upper die 20 has a plate-shaped upper holder 22 that is fixed to the underside of an upper ram (not shown) of the press machine. This allows the upper die 20 to move up and down so as to move toward and away from the lower die 60. In the upper die 20, a backing plate 24 and a punch plate 26 are attached to the lower part of the upper holder 22. The punch plate 26 fixes a pilot hole punch 28, a slot punch 30, an inner shape punch 34, and an outer shape punch 36 to the upper holder 22, respectively.

[0083] In the upper mold 20, a stripper 40 is attached below the upper holder 22. The stripper 40 is movable in the vertical direction relative to the upper holder 22. The stripper 40 is suspended by a suspension bolt (not shown) and is set at its lowest position relative to the upper holder 22. The stripper 40 is configured as a joined body of a stripper body 40A and a stripper body 40B, each of which has a plate shape.

[0084] The lower surface of the stripper 40 faces the upper surfaces of a die plate 64 (described later) and the dies 68, 70, 74, and 76. The stripper 40 has punch through-holes 42, 44, 48, and 50 through which the punches 28, 30, 34, and 36 pass.

[0085] The lower die 60 has a plate-shaped lower holder 62 that is fixed to the upper surface of a lower bolster (not shown) of the press machine. The lower holder 62 is disposed opposite the upper holder 22. In the lower die 60, a plate-shaped die plate 64 is attached to the upper surface of the lower holder 62. Attached to the die plate 64 are a pilot hole punching die 68, a slot punching die 70, an inner shape punching die 74, an adhesive application device 90, and an outer shape punching die 76. The outer shape punching die 76 is cylindrical and constitutes a rotary die that is divided and rotated at a predetermined rotation angle around its own central axis.

[0086] The punches 28, 30, 34, 36 and the dies 68, 70, 74, 76 correspond to each other and constitute individual processing stages spaced apart from one another in the direction of transport of the strip-shaped thin sheet F. As processing stages, the pilot hole punching punch 28 and the pilot hole punching die 68 constitute a pilot hole punching stage (pilot hole forming section) I, the slot punch 30 and the slot punching die 70 constitute a slot punching stage II, the inner shape punching punch 34 and the inner shape punching die 74 constitute an inner shape punching stage III, and the outer shape punching punch 36 and the outer shape punching die 76 constitute an outer shape punching stage V. Between the inner shape punching stage III and the outer shape punching stage V, an adhesive application stage IV is formed by an adhesive application device 90.

[0087] The slot punching stage II, the inner shape punching stage IV, the adhesive application stage IV, and the outer shape punching stage V are each processing stages that perform a predetermined process in the progressive die device 10. The punches 28, 30, 34, 36, dies 68, 70, 74, 76, and adhesive application device 90 provided in each of stages II to V constitute processing members that perform a predetermined process on the strip-shaped thin sheet F in each of the above-mentioned processing stages. In this way, processing members that perform a predetermined process on the strip-shaped thin sheet F are installed in each processing stage.

[0088] In other words, as processing members, the pilot hole punching stage I is equipped with a pilot hole punch 28 and a pilot hole punching die 68, the slot punching stage II is equipped with a slot punch 30 and a slot punching die 70, the inner shape punching stage III is equipped with an inner shape punching punch 34 and an inner shape punching die 74, the adhesive application stage IV is equipped with an adhesive application device 90, and the outer shape punching stage V is equipped with an outer shape punching punch 36 and an outer shape punching die 76.

[0089] The progressive die device 10 has an intermediate idle stage I1 between the adhesive application stage IV and the outer shape punching stage V, and a final idle stage I2 on the forward side (downstream side) of the outer shape punching stage V in the transfer direction. In each of the idle stages I1 and I2, the strip-shaped thin plate F is fed empty.

[0090] As a result, the progressive die device 10 is configured with a pilot hole punching stage I, a slot punching stage II, an inner shape punching stage III, an adhesive application stage IV, an intermediate idle stage I1, an outer shape punching stage V, and a final idle stage I2, which are arranged in this order at predetermined intervals in the transport direction of the strip-shaped sheet metal F. The interval between the pilot hole punching stage I and the slot punching stage II is set to 1.5 times the transport pitch T of the strip-shaped sheet metal F, and the interval between adjacent stages is set to a value equal to the transport pitch T of the strip-shaped sheet metal F.

[0091] [Amendment based on Rule 91 26.01.2024] In the pilot hole punching stage I, the pilot hole punching process is carried out using a plurality of pilot hole punching punches 28 and a plurality of pilot hole punching dies 68 corresponding to each pilot hole punching punch 28, and a plurality of circular pilot holes P are punched in the strip sheet F with each press operation, i.e., with each intermittent transfer of the strip sheet F. The pilot holes P are formed along the vicinity of each of the left and right side edges of the strip sheet F, aligned in the transfer direction of the strip sheet F (see FIG. 6 ).

[0092] In the slot punching stage II, a slot punching process is carried out using a slot punching punch 30 and a slot punching die 70, and a slot S (see FIG. 6) is punched into the strip-shaped sheet metal F with each press operation. The slots S are arranged at predetermined intervals in the circumferential direction and correspond to the regions between the multiple tooth portions C formed in the strip-shaped sheet metal F. The slot punching punch 30 and the slot punching die 70 are provided corresponding to each slot S.

[0093] In the inner shape punching stage III, the inner shape punching step is carried out by the inner shape punching punch 34 and the inner shape punching die 74, and with each press operation, a circular inner shape G (see FIG. 6) is punched out of the strip-shaped thin plate F. As a result, with each press operation, a plurality of teeth C (including portions that define the inner edge) are punched out of the strip-shaped thin plate F.

[0094] In the adhesive application stage IV, adhesive application is carried out by the adhesive application device 90 .

[0095] The adhesive application device 90 has an upper block 92 and a lower block 94 that are integrally joined to each other. The upper block 92 and the lower block 94 cooperate to define an adhesive reservoir chamber 96. Liquid adhesive pressurized to a predetermined pressure is supplied to the adhesive reservoir chamber 96 from an adhesive passage 98 formed in the lower block 94. A plurality of adhesive discharge ports 100 that communicate with the adhesive reservoir chamber 96 are formed through the upper wall of the upper block 92. Each of the plurality of adhesive discharge ports 100 opens into the flat upper surface of the upper block 92. The adhesive supplied to the adhesive reservoir chamber 96 has a predetermined viscosity, so that each adhesive discharge port 100 forms a substantially hemispherical raised portion K that rises upward from the open end relative to the upper surface of the upper block 92.

[0096] The combination of the upper block 92 and the lower block 94 is engaged with block receiving holes 102 formed in the lower holder 62 and the die plate 64 so as to be slidable in the vertical direction. A plate cam 106 including a sawtooth cam portion 104 is provided on the underside of the lower holder 62 so as to be movable in the left-right direction as viewed in Figure 7. A sawtooth cam portion 108 corresponding to the cam portion 104 is formed on the underside of the lower block 94. As the plate cam 106 moves, the combination of the upper block 92 and the lower block 94 moves between an elevated position where the upper surface of the upper block 92 is substantially flush with the upper surface of the die plate 64 or is slightly below the upper surface of the die plate 64, and a lowered position below the elevated position, as shown in Figure 7.

[0097] The combination of the upper block 92 and the lower block 94 is in the raised position except during measurement to set the number of laminated core thin plates A. In this raised position, the adhesive in the raised portion K comes into contact with and is transferred to the underside of the strip-shaped thin plate F as the stripper 40 descends, causing the strip-shaped thin plate F to descend toward the upper surface of the die plate 64. In this way, the adhesive is applied to each bonding point J of the strip-shaped thin plate F. During measurement to set the number of laminated core thin plates A, the combination of the upper block 92 and the lower block 94 is in the lowered position, so that even when the strip-shaped thin plate F descends toward the upper surface of the die plate 64, the adhesive in the raised portion K does not come into contact with the underside of the strip-shaped thin plate F, and adhesive is not applied to the strip-shaped thin plate F.

[0098] In the outer shape punching stage V, an outer shape punching step is carried out by the outer shape punching punch 36 and the outer shape punching die 76, and with each press operation, a circular outer shape H (see FIG. 2) is punched out of the strip-shaped thin plate F. In this way, one iron core thin plate A is punched out of the strip-shaped thin plate F.

[0099] The core thin plates A completed by punching out the outer shape H are pushed into the outer shape punching die 76 by the outer shape punching punch 36, and are stacked in order on top of the previously punched core thin plates A inside the outer shape punching die 76. The multiple core thin plates A stacked inside the outer shape punching die 76 are bonded (joined) to one another by the adhesive at each bonding point J.

[0100] In the outline punching stage V, when the upper die 20 descends to start punching the outline H, the stripper 40 descends together with the upper die 20. At this time, the strip-shaped sheet F is essentially stopped when not being conveyed (including cases where it is not strictly stopped). The descending stripper 40 presses the upper surface of the strip-shaped sheet F downward with its lower surface. At this time, the strip-shaped sheet F is sandwiched between the lower surface of the stripper 40 and the upper surface of the lower die 60.

[0101] When the upper die 20 rises after punching out the outer shape H, the stripper 40 rises together with the upper die 20. As a result, the stripper 40 is released from pressing the strip-shaped sheet F, and the strip-shaped sheet F is separated from the upper surface of the lower die 60. In this state, the strip-shaped sheet F is transported a predetermined feed amount in the forward feed direction.

[0102] The operation of the stripper 40 is the same in the other stages IV.

[0103] 4, pilot pins 80 are attached to the upper mold 20 at each of the stages II to V, I1, and I2 after stage I. Each pilot pin 80 engages with a corresponding pilot hole P at each of the stages II to V, I1, and I2 to position the belt-shaped thin plate F at each of the stages II to V, I1, and I2.

[0104] In the second embodiment, as in the first embodiment, a pilot pin 80 is attached to the punch plate 26 for each of the stages I to V, I1, and I2 in a state in which the pilot pin 80 is spring-biased downward by a compression coil spring 82, as shown in Fig. 4. The pilot pins 80 are provided near the left and right side edges Fa, Fb of the belt-shaped thin plate F. The pilot pins 80 on both the left and right sides of the punch plate 26 corresponding to the pilot holes P pass through pin through holes 84 formed in the stripper 40 and are exposed toward the upper surface of the die plate 64.

[0105] As the upper die 20 descends, the pilot pin 80 passes through the pilot hole P in the strip-shaped sheet F and engages with a pilot pin receiving hole 86 formed in the die plate 64. This engagement positions the strip-shaped sheet F relative to the progressive die device 10.

[0106] Next, the formation of the plurality of pilot holes P in the pilot hole punching stage I and the arrangement of the pilot pins 80 in each of the stages II to V, I1, and I2 after stage I will be described.

[0107] [Correction based on Rule 91 26.01.2024] As shown in Figure 6, the pilot hole punching punches 28 and pilot hole punching dies 68 in the pilot hole punching stage I are provided in pairs, aligned in the direction of transport of the strip of sheet metal F, at positions corresponding to the vicinity of each of the left and right side edges Fa, Fb of the strip of sheet metal F.

[0108] 6, two pilot holes P are formed near each side edge Fa, Fb of the strip sheet F each time the strip sheet F is fed, aligned in the feeding direction of the strip sheet F. For convenience of explanation, even in the second embodiment, the pilot hole P on the leading side (leading side) in the feeding direction of the two pilot holes P may be referred to as the front pilot hole Pa, and the pilot hole P on the trailing side (lagging side) in the feeding direction of the two pilot holes P may be referred to as the rear pilot hole Pb.

[0109] The front pilot hole Pa and the rear pilot hole Pb are pilot holes formed for each transfer, and the front pilot holes Pa and the rear pilot holes Pb in the same row are formed at a predetermined interval that is smaller than the transfer pitch T in the transfer direction of the strip-shaped thin plate F. Pairs of the front pilot hole Pa and the rear pilot hole Pb are provided in each of stages II to V, respectively, in front of and behind the position of the processing member in each of stages II to V. In other words, pairs of the front pilot hole Pa and the rear pilot hole Pb are formed in two locations in each of stages II to V, separated by the processing member in each of stages II to V in the transfer direction of the strip-shaped thin plate F. In embodiment 2 as well, the pair of the front pilot hole Pa and the rear pilot hole Pb in front of the position of the processing member is called the front pair, and the pair of the front pilot hole Pa and the rear pilot hole Pb behind the position of the processing member is called the rear pair.

[0110] [Correction under Rule 91 26.01.2024] In one of Stages II to V, the pilot pin 80 is arranged to use the front pilot hole Pa of the two pilot holes P, and in another of Stages II to V, the pilot pin 80 is arranged to use the rear pilot hole Pb of the two pilot holes P. That is, in one of Stages II to V, the pilot pin 80 is arranged to engage with one of the two pilot holes P, and in another of Stages II to V, the pilot pin 80 is arranged to engage with one of the two pilot holes P other than the one mentioned above. As a result, in at least one of Stages II to V, there is at least one pilot hole P that does not engage with the pilot pin 80.

[0111] This specific example will be described using the strip layout (single row) in Fig. 6. In Fig. 6, the pilot holes P with which the pilot pins 80 engage are indicated by circles with cross marks, and unused pilot holes P with which the pilot pins 80 do not engage are indicated by hollow circles.

[0112] In slot punching stage II, in both the front pair and the rear pair, the pilot pins 80 engage with the rear pilot holes Pb, but do not engage with the front pilot holes Pa. In other words, the front pilot holes Pa are unused.

[0113] In the internal shape punching stage III, in order to perform highly accurate internal shape punching, the pilot pin 80 engages with the pilot hole located close to the processing member (the internal shape punching punch 34 and the internal shape punching die 74), that is, in the front pair, the pilot pin 80 engages with the rear pilot hole Pb, and in the rear pair, the pilot pin 80 engages with the front pilot hole Pa.

[0114] The front pair of slot punching stage II, which is located between slot punching stage II and inner shape punching stage III, constitutes the rear pair of inner shape punching stage III. In the front pair of slot punching stage II, in other words, in the rear pair of inner shape punching stage III, the pilot pins 80 engage with both the front pilot hole Pa and the rear pilot hole Pb.

[0115] In adhesive application stage IV, so that the pilot pin 80 does not interfere with the adhesive application device 90 (processing member), the pilot pin 80 engages with a pilot hole located away from the adhesive application device 90, i.e., the front pilot hole Pa in the front pair, and the pilot pin 80 engages with the rear pilot hole Pb in the rear pair.

[0116] In the contour punching stage V, so that the pilot pin 80 does not interfere with the contour punching die 76 (processing member), which is a rotary die, the pilot pin 80 engages with a pilot hole located away from the contour punching die 76, that is, the front pilot hole Pa in the front pair, and the rear pilot hole Pb in the rear pair.

[0117] In the intermediate idle stage I1 and the final idle stage I2, in order to suppress vibration of the strip-shaped thin plate F due to processing impact, the pilot pin 80 engages with the pilot hole on the side of the front pair and the rear pair where the separation distance in the transport direction of the strip-shaped thin plate F is shorter, that is, the rear pilot hole Pb in the front pair, and the pilot pin 80 engages with the front pilot hole Pa in the rear pair.

[0118] At each stage, the pilot pins 80 are arranged so that they engage with the front pilot holes Pa or rear pilot holes Pb described above, which increases the degree of freedom in the arrangement position of the pilot holes P with which the pilot pins 80 engage in relation to the transport direction of the strip-shaped thin plate F. Accordingly, the degree of freedom in the arrangement position of the pilot pins 80 increases in relation to the transport direction of the strip-shaped thin plate F.

[0119] This allows the pilot pin 80 to be easily positioned at a position where it does not interfere with the adhesive application device 90 or the outer shape punching die 76, which is a rotary die.

[0120] In other words, even if one of the front pilot hole Pa and the rear pilot hole Pb is formed in a position where it interferes with a processing member of a certain processing stage, such as the adhesive application device 90 or the contour punching die 76, the pilot pin 80 does not engage with the front pilot hole Pa or the rear pilot hole Pb that is in the interfering position, and the pilot pin 80 engages with the other front pilot hole Pa or the rear pilot hole Pb that is formed in a non-interfering position, so that the role of the pilot hole P is fulfilled in each processing stage without complicating the structure of the plate cam 38 or the contour punching die 76.

[0121] As a result, in embodiment 2, as in embodiment 1, high-precision iron core thin plates A can be repeatedly manufactured by appropriately positioning the strip-shaped thin plate F relative to the progressive die device 10 based on the engagement between the pilot hole P and the pilot pin 80.

[0122] In the second embodiment, it is possible to apply the two-row arrangement as in the first embodiment.

[0123] While the present invention has been described above in terms of preferred embodiments, it will be readily understood by those skilled in the art that the present invention is not limited to such embodiments and can be modified as appropriate without departing from the spirit of the present invention. For example, the front pilot hole Pa and the rear pilot hole Pb on the same side may be offset from each other in the width direction of the strip-shaped sheet F. The number of pilot holes P in each row punched and formed during each transfer of the strip-shaped sheet F during intermittent transfer is not limited to two, and may be three or more as long as it is within the range of one transfer pitch T.

[0124] The pilot pin 80 and the pilot hole P are not limited to being located near the left and right side edges of the strip-shaped thin plate F, but may be located in a position that does not interfere with the processing member between the left and right side edges. In each processing stage, the pilot hole P with which the pilot pin 80 engages may be different on the left side edge Fa side and the right side edge Fb side of the strip-shaped thin plate F. For example, the side edge Fa side may be the rear pilot hole Pb, and the side edge Fb side may be the front pilot hole Pa.

[0125] 10: Progressive die device 20: Upper die 22: Upper holder 24: Backing plate 26: Punch plate 28: Pilot hole punching punch 30: Slot punching punch 32: Caulking portion forming punch 34: Inner shape punching punch 36: Outer shape punching punch 38: Plate cam 40: Stripper 40A: Stripper body 40B: Stripper 42: Punch through hole 44: Punch through hole 46: Punch through hole 48: Punch through hole 50: Punch through hole 60: Lower die 62: Lower holder 64: Die plate 68: Pilot hole punching die 70: Slot punching die 72: Caulking portion forming die 74: Inner shape punching die 76 : Outer shape punching die 80 : Pilot pin 82 : Compression coil spring 84 : Pin through hole 86 : Pilot pin receiving hole 90 : Adhesive application device 92 : Upper block 94 : Lower block 96 : Adhesive reservoir chamber 98 : Adhesive passage 100 : Adhesive discharge port 102 : Block receiving hole 104 : Cam portion 106 : Plate cam 108 : Cam portion A : Core thin plate B : Yoke portion C : Teeth portion D : Caulking portion F : Strip-shaped thin plate Fa : Side edge Fb : Side edge G : Inner shape H : Outer shape I : Pilot hole punching stage (Embodiments 1 and 2) II : Slot punching stage (Embodiments 1 and 2) III : Caulking portion forming stage (Embodiment 1) III : Inner shape punching stage (Embodiment 2) IV: Inner shape punching stage (Embodiment 1) IV: Adhesive application stage (Embodiment 2) V: Outer shape punching stage (Embodiments 1 and 2) I1: Intermediate idle stage (Embodiments 1 and 2) I2: Final idle stage (Embodiments 1 and 2) J: Bonding point K: Protruding portion P: Pilot hole Pa: Front pilot hole Pb: Rear pilot hole S: Slot T: Transfer pitch

Claims

1. A progressive die device which manufactures iron core sheets of a predetermined shape by performing a predetermined processing on a strip-shaped thin plate which is intermittently transferred at a predetermined pitch in each of a plurality of processing stages which are aligned in the transfer direction of the strip-shaped thin plate, the progressive die device having: a pilot hole forming section which punches out and forms a plurality of pilot holes for each transfer of the strip-shaped thin plate during intermittent transfer; and at least one pilot pin which is provided corresponding to each of the processing stages and engages with the corresponding pilot hole to position the strip-shaped thin plate in each processing stage, wherein in one of the processing stages, the pilot pin is positioned so as to engage with one of the plurality of pilot holes, and in another of the processing stages, the pilot pin is positioned so as to engage with one of the plurality of pilot holes other than the one.

2. The progressive die device according to claim 1, wherein the pilot hole forming section is configured so that the plurality of pilot holes are aligned in the transport direction.

3. A progressive die device according to claim 1, wherein the pilot hole forming section is configured so that the plurality of pilot holes are aligned in the conveying direction along each of the two side edges of the strip-shaped thin plate.

4. A progressive die device as described in any one of claims 1 to 3, wherein a processing member for performing a predetermined processing on the strip-shaped thin plate is installed in each of the processing stages, and the pilot pin engages with one of a plurality of pilot holes formed at a plurality of locations in each of the processing stages, spaced apart from the processing member in the transport direction, that does not interfere with the processing member.

5. A progressive die device as described in claim 4, which has as one of the processing stages a crimped portion forming stage equipped with a crimped portion forming punch and a crimped portion forming die for forming a crimped portion in the strip-shaped thin plate, and a cam for increasing or decreasing the effective length of the crimped portion forming punch, and wherein the processing member that is subject to interference with the pilot pin is the cam.

6. A progressive die apparatus as described in claim 4, wherein one of the processing stages is an adhesive application stage equipped with an adhesive application device for applying adhesive to the strip-shaped thin plate, and the processing member that is subject to interference with the pilot pin is the adhesive application device.

7. A progressive die device as described in claim 4, wherein one of said processing stages is a punching stage equipped with a punch and a rotary die, and said processing member which is subject to interference with said pilot pin is said rotary die.

8. A manufacturing method for manufacturing iron core thin plates of a predetermined shape by performing a predetermined processing on a strip-shaped thin plate that is intermittently transferred at a predetermined pitch in each of a plurality of processing stages that are aligned in the transfer direction of the strip-shaped thin plate using a progressive die device, wherein a pilot hole forming section punches out a plurality of pilot holes each time the strip-shaped thin plate is transferred intermittently, at least one pilot pin is provided corresponding to each of the processing stages and engages with the corresponding pilot hole to position the strip-shaped thin plate in each of the processing stages, and the pilot pin engages with one of the plurality of pilot holes in one of the processing stages, and engages with one of the plurality of pilot holes other than the one in another of the processing stages.

9. The method of claim 8, wherein said plurality of pilot holes are aligned in said transfer direction.

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