Punching device and lift stage

Abstract

Provided is a punching device having a simplified structure. This punching device comprises an adhesive application stage 15, a punching stage 13, and a lift stage 17. The lift stage 17 includes a fixed-side receiving surface 18, a relief portion 20, and a lifter 29. The fixed-side receiving surface 18 receives a lower surface WL of a steel sheet W when a punching target region R is punched on the punching stage 13. The relief portion 20 avoids contact between the fixed-side receiving surface 18 and an adhesive G applied to the lower surface WL of an upstream punching target region Ru. The lifter 29 protrudes so as to be retractable with respect to the fixed-side receiving surface 18. When protruded, the lifter 29 supports the lower surface WL of the upstream punching target region Ru at a position in the feed direction of the steel sheet W that does not overlap with the adhesive G. When retracted, the lifter 29 allows the steel sheet W to be received on the fixed-side receiving surface 18.

Description

Punching device and lift stage

[0001] The present invention relates to a punching device for punching core pieces used in laminated cores for rotating electrical machines, and a lift stage used therefor.

[0002] A conventional punching device, as disclosed in Patent Document 1, applies adhesive to a strip-shaped steel plate using an adhesive applicator, and then punches core pieces from the steel plate in a die and stacks them.

[0003] This punching device has guide pins that guide the feed of the strip-shaped steel sheet from the adhesive applicator to the die. The guide pins support the underside of both widthwise ends of the steel sheet. The punching device also has holders across the feed direction that hold the entire widthwise steel sheet from the underside.

[0004] In such a punching device, the steel plate is pushed up above the holder by the guide pins to feed the steel plate, and even if the steel plate sags at the center in the width direction, it is held by the holder.

[0005] However, conventional punching devices have a complex structure, as they use guide pins to push up the steel plate at both widthwise ends, and separately use a holder to hold the steel plate hanging down between the widthwise guide pins.

[0006] Patent No. 6742492

[0007] The problem to be solved is that the punching device has a complicated structure.

[0008] The present invention provides a punching device comprising: an adhesive application stage that sequentially applies dots of adhesive to the underside of multiple punching areas having a circumferential outer shape of a strip-shaped steel sheet; a punching stage that sequentially punches the multiple punching areas as the steel sheet is fed to laminate multiple punched pieces with the adhesive; and a lift stage that is provided between the adhesive application stage and the punching stage and that supports the steel sheet from the underside while avoiding the adhesive as it is fed and that keeps an upstream punching area, which is a planned punching area located upstream of the planned punching area, waiting when the planned punching area is punched in the punching stage. The lift stage comprises a fixed receiving surface that receives the underside of the steel sheet when the planned punching area is punched in the punching stage, a relief portion that prevents contact between the fixed receiving surface and the adhesive applied to the underside of the upstream planned punching area, and a lifter that protrudes and can be retracted from the fixed receiving surface. The lifter supports the lower surface of the upstream punching range at a position that does not overlap with the adhesive in the feed direction of the steel plate by protruding, and enables the steel plate to be received by the fixed side receiving surface by retracting.

[0009] The present invention also provides a lift stage for holding an upstream planned punching range, which is a planned punching range located upstream of a planned punching range that has a circular outer shape and has a circular dotted adhesive applied to its underside, when punching from a strip-shaped steel sheet in the planned punching range. This lift stage includes a fixed receiving surface that receives the underside of the steel sheet when punching the planned punching range, a relief portion that prevents contact between the fixed receiving surface and the adhesive applied to the underside of the upstream planned punching range, and a lifter that protrudes and can be retracted from the fixed receiving surface. The protrusion of the lifter supports the underside of the upstream planned punching range at a position that does not overlap with the adhesive in the feed direction of the steel sheet, and the retraction allows the steel sheet to be received by the fixed receiving surface.

[0010] In the present invention, the structure of the punching device can be simplified.

[0011] FIG. 1 is a schematic cross-sectional view showing a portion of a punching device according to a first embodiment of the present invention. FIG. 2 is a schematic plan view showing a portion of the punching device of FIG. 1. FIG. 3 is a schematic cross-sectional view taken along III-III in FIG. 2, showing the lift stage when the lifter is raised. FIG. 4 is a schematic cross-sectional view taken along III-III in FIG. 2, showing the lift stage when the lifter is lowered. FIG. 5 is a schematic cross-sectional view taken along V-V in FIG. 2, showing the lift stage when the lifter is raised. FIG. 6 is a block diagram showing the processing flow of the punching device of FIG. 1. FIG. 7 is a plan view showing a steel plate punched by the punching device of FIG. 1, together with the adhesive application position. FIG. 8 is a schematic plan view showing a modified lifter. FIG. 9 is a schematic plan view showing another modified lifter. FIG. 10 is a schematic cross-sectional view showing yet another modified lifter. FIG. 11 is a schematic cross-sectional view showing yet another modified lifter.

[0012] The punching device 1 of one embodiment includes an adhesive application stage 15, a punching stage 13, and a lift stage 17. The adhesive application stage 15 sequentially applies adhesive G in dots to the underside of a plurality of planned punching areas R, each having a circular outer shape, of a strip-shaped steel sheet W. The punching stage 13 sequentially punches out the plurality of planned punching areas R in accordance with the feed of the steel sheet W, and stacks the plurality of punched pieces 2 with the adhesive G. The lift stage 17 is provided between the adhesive application stage 15 and the punching stage 13, and supports the steel sheet W from the underside WL while avoiding the adhesive G when the steel sheet W is fed, and also allows an upstream planned punching area Ru, which is a planned punching area R located upstream of the planned punching area R, to wait when the planned punching area R is punched by the punching stage 13.

[0013] The lift stage 17 includes a fixed-side receiving surface 18, a recess 20, and a lifter 29. The fixed-side receiving surface 18 receives the underside WL of the steel sheet W when the planned punching range R is punched on the punching stage 13. The recess 20 prevents contact between the fixed-side receiving surface 18 and the adhesive G applied to the underside WL of the planned upstream punching range Ru. The lifter 29 protrudes so as to be retractable relative to the fixed-side receiving surface 18. By protruding, the lifter 29 supports the underside WL of the planned upstream punching range Ru at a position that does not overlap with the adhesive G in the feed direction of the steel sheet W, and by retracting, it allows the fixed-side receiving surface 18 to receive the steel sheet W.

[0014] The lifter 29 can be formed in any suitable form, and may, for example, have a plurality of convex rib portions 29aa and 29ab along the feed direction that support the lower surface WL of the upstream punching range Ru, and a concave rib portion 29b that avoids adhesive G between the convex rib portions 29aa and 29ab.

[0015] The lifter 29 can be disposed at any suitable position, and may be disposed, for example, at the center side of the upstream planned punching range Ru where the lifter 29 waits in the width direction of the steel sheet W. In this case, the escape portion 20 may be provided with an escape recess 27 that allows the adhesive G to escape outside the lifter 29 in the width direction.

[0016] The planned punching range R may include an inner peripheral punching portion 36, and the lifter 29 may support the lower surface WL of the upstream planned punching range Ru so as to cross over to the inner peripheral punching portion 36 in the feed direction.

[0017] The lifter 29 may be longer in the feed direction than the diameter of the inner peripheral punched portion 36 .

[0018] The lift stage 17 may be adjacent to the adhesive application stage 15 downstream in the feed direction and the punching stage 13 upstream in the feed direction.

[0019] [Punching device] Fig. 1 is a schematic cross-sectional view showing a part of a punching device according to Example 1 of the present invention. Fig. 2 is a schematic plan view of the punching device of Fig. 1. In the following description, the Z direction means the up-down direction of the punching device, the X direction means the feed direction of the strip-shaped steel plate, and the Y direction means the width direction of the steel plate.

[0020] 1 and 2 , a strip-shaped steel sheet W is fed in the X direction into the punching device 1 to punch out core pieces 2. In this embodiment, the steel sheet W is an electromagnetic steel sheet. The core pieces 2 are annular plates, and a plurality of core pieces 2 are stacked to form a stator 4 of a rotating electric machine. Note that the punching device 1 may also be used to punch out disc-shaped rotor core pieces used in the rotor of a rotating electric machine.

[0021] The punching device 1 of this embodiment includes an inner peripheral punching stage 11, an outer peripheral punching stage 13, an adhesive application stage 15, and a lift stage 17. Between the inner peripheral punching stage 11 and the outer peripheral punching stage 13, the adhesive application stage 15 and the lift stage 17 are arranged in this order in the X direction.

[0022] That is, the lift stage 17 is provided between the adhesive application stage 15 and the outer periphery punching stage 13, which serves as the punching stage in this embodiment, and is adjacent to the adhesive application stage 15 downstream in the X direction and the outer periphery punching stage 13 upstream in the X direction. Note that a shape punching stage such as the inner periphery punching stage 13 or a slot 35 (see FIG. 7 ), which will be described later, may be disposed between the lift stage 17 and the adhesive application stage 15. Furthermore, when a shape punching stage is disposed downstream of the adhesive application stage 15, the shape punching stage may be the lift stage 17.

[0023] The inner peripheral punching stage 11 forms slots 35 in the core pieces 2 by inner peripheral punching. The slots 35 are punched out in advance into a closed planar shape by shape punching in the shape punching stage, and are then formed with an open inner peripheral side by inner peripheral punching in the inner peripheral punching stage 11. The outer peripheral punching stage 13 sequentially punches out a plurality of planned punching ranges R in accordance with the feed of the steel sheet W, and laminates the plurality of core pieces 2 with adhesive G (see FIG. 7 ).

[0024] This punching device 1 is equipped with an upper die 3 and a lower die 5. The upper die 3 is attached to a press ram 7, and the lower die 5 is attached to a bolster 9. The upper die 3 is common to the inner peripheral punching stage 11 and the outer peripheral punching stage 13, and is equipped with punches 19 and 21 for the inner peripheral punching stage 11 and the outer peripheral punching stage 13. A stripper 22 is provided at the tip of the punches 19 and 21.

[0025] The lower die 5 includes lower dies 11 a, 13 a, and 17 a corresponding to the inner peripheral punching stage 11 , the outer peripheral punching stage 13 , and the lift stage 17 .

[0026] The lower die 11a of the inner peripheral punching stage 11 has a die 12, and the lower die 13a of the outer peripheral punching stage 13 has a die 14a and a squeeze die 14b connected thereto. The lower die 17a of the lift stage 17 is integrally formed with the lower die 13a of the outer peripheral punching stage 13.

[0027] The lower dies 13a and 17a have continuous upper surfaces 18, which form a fixed-side receiving surface. In this embodiment, the fixed-side receiving surface is the receiving surface of the lower die 17a, which is the fixed side. This receiving surface is the surface that receives the steel sheet W on the lift stage 17 at least during outer periphery punching in the outer periphery punching stage 13. The upper surfaces 18 of the lower dies 13a and 17a are flush, but a step may be provided between them as long as the steel sheet W can be received thereon.

[0028] The adhesive application stage 15 sequentially applies adhesive G in dots to the underside WL of a plurality of intended punching areas R (see FIG. 7 ) having a circular outer shape of the steel sheet W. Dot application means that the adhesive G is applied in circular dots spaced apart in a plan view. However, as long as there is a space between the applied adhesive G, the shape of the adhesive G in a plan view, etc., is free.

[0029] The adhesive application stage 15 is equipped with an adhesive application device 23. At least an application section 24 of the adhesive application device 23 for applying adhesive G is disposed between the lower die 11a of the inner peripheral punching stage 11 and the lower die 17a of the lift stage 17. Although not shown, a portion of the adhesive application device 23 is located within the lower die 17a of the lift stage 17.

[0030] A plurality of discharge holes 24a are arranged circumferentially in the application section 24 of the adhesive application device 23. In this embodiment, the plurality of discharge holes 24a are arranged circumferentially at regular intervals. The adhesive G stored in a tank (not shown) is delivered to the discharge holes 24a at a predetermined pressure, and the adhesive G held thereby is brought into contact with the steel sheet W to be applied.

[0031] Fig. 3 is a schematic cross-sectional view taken along III-III in Fig. 2, showing the lift stage 17 when the lifter 29 is raised. Fig. 4 is a schematic cross-sectional view taken along III-III in Fig. 2, showing the lift stage 17 when the lifter 29 is lowered. Fig. 5 is a schematic cross-sectional view taken along VV in Fig. 2, showing the lift stage 17 when the lifter 29 is raised.

[0032] 1 to 5, the lift stage 17 supports the steel sheet W from the lower surface WL while avoiding the adhesive G when feeding the steel sheet W. Furthermore, when punching the planned punching range R in the outer peripheral punching stage 13, the lift stage 17 causes the upstream planned punching range Ru, which is the planned punching range R located upstream of this planned punching range R, to wait. "Waiting" here means that the feeding of the steel sheet W is temporarily stopped and the planned upstream punching range Ru is positioned above the lift stage 17. When the lift stage 17 is configured by a shape punching stage, the waiting of the upstream planned punching range Ru means that the upstream planned punching range Ru is positioned above the shape punching stage.

[0033] The lift stage 17 includes an upper surface 18 that is a fixed receiving surface, a recess 20 , and a lifter 29 .

[0034] The relief portion 20 prevents contact between the upper surface 18 and the adhesive G applied to the lower surface WL of the upstream planned punching range Ru, and in this embodiment has a plurality of relief recesses 27. The plurality of relief recesses 27 are arranged in a circumferential shape so as to separately receive the adhesive G in the upstream planned punching range Ru waiting on the lift stage 17. However, by making the relief recesses 27 as small as possible, for example by arranging them only in the portions corresponding to the adhesive G, the contact area between the steel sheet W and the upper surface 18 increases, and the steel sheet W can be held stably.

[0035] The relief recess 27 may be formed as a single recess that is continuous in an annular shape. Alternatively, several relief recesses 27 may be combined to form an arc-shaped recess in a plan view. Furthermore, the relief recess 27 may be a single recess that is circular, rectangular, or the like in a plan view, in which the lifter 29 can also be disposed.

[0036] The relief recess 27 in this embodiment is provided on the outer side in the Y direction relative to the lifter 29. On the lifter 29, a groove 29b, which will be described later, functions as the relief portion 20.

[0037] The lifter 29 is disposed in the accommodation recess 25. The accommodation recess 25 is provided in the center in the Y direction of the lower mold 17a in the lift stage 17. The accommodation recess 25 is formed in a rectangular shape in plan view on the upper surface 18 of the lower mold 17a.

[0038] The width in the Y direction and the length in the X direction of the accommodating recess 25 are set in accordance with the lifter 29. However, the accommodating recess 25 can also be formed larger in the Y direction than the lifter 29 so that it also serves as a relief recess.

[0039] The depth of the accommodation recess 25 in the Z direction is formed to be deeper than the thickness of the lifter 29 in the Z direction, so that the upper surface of the lifter 29 can be retracted relative to the upper surface 18 of the lower mold 17a.

[0040] The lifter 29 of this embodiment has a plurality of ridges 29a and recesses 29b. Two ridges 29aa are arranged on the central side of the lifter 29 in the Y direction, which is the width direction of the electromagnetic steel sheet W. The ridges 29ab are arranged on both edges of the lifter 29 in the Y direction. The ridges 29aa on the central side of the lifter 29 are thicker in the Y direction than the ridges 29ab on both sides.

[0041] With this configuration, the upstream planned punching area Ru can be supported from the underside WL by the convex rib portion 29aa at locations where the distance in the Y direction between adjacent adhesives G is wide among the adhesives G that are applied and arranged in a circumferential shape. On the other hand, the upstream planned punching area Ru can be supported from the underside WL by the convex rib portion 29ab at locations where the distance in the Y direction between adjacent adhesives G is relatively narrow.

[0042] The thickness of the protruding rib portion 29aa in the Y direction can improve the support rigidity of the steel plate W by the lifter 29. In addition, by making the height of the protruding rib portions 29aa and 29ab in the Z direction as low as possible, the support rigidity of the steel plate W by the lifter 29 can also be increased.

[0043] The protruding portions 29aa and 29ab are provided so as to protrude in a rectangular shape in cross section along the Y direction, and are formed along the X direction, which is the feed direction, over the entire length of the lifter 29. The upper surfaces of the protruding portions 29aa and 29ab support the lower surface WL of the upstream planned punching range Ru, avoiding the adhesive G applied to the steel plate W.

[0044] The planned punching range R, where the adhesive G is applied, includes an inner peripheral punching portion 36 (described later) punched by the inner peripheral punching stage 11, and the lifter 29 supports the lower surface WL of the planned upstream punching range Ru so as to cross over the inner peripheral punching portion 36 in the X direction. The lifter 29 in this embodiment is formed to have a larger diameter than the inner peripheral punching portion 36. The diameter of the inner peripheral punching portion 36 here is defined by an imaginary circle that passes through the bottom of the concave slot 35 in a plan view.

[0045] Note that the lifter 29 only needs to span the inner peripheral cutout portion 36 in the X direction, and may span between the tips of the teeth 38. The lifter 29 may also be positioned offset in the Y direction relative to this embodiment, and the number of ridge portions 29aa and 29ab may be changed. For example, the lifter 29 may have a single ridge portion 29aa or 29ab. In this case, the lifter 29 may be shaped to span in the X direction between multiple teeth 38 located at the ends in the Y direction.

[0046] The recessed streak portion 29b is formed between the adjacent protruding streak portions 29aa and 29ab in the Y direction. The recessed streak portion 29b has a width and depth sufficient to avoid the adhesive G, and penetrates the lifter 29 in the X direction.

[0047] The lifter 29 protrudes retractably from the upper surface 18. In this embodiment, the lifter 29 is supported by a post 31 at the bottom of the accommodating recess 25. An elastic member 33 is attached to the post 31 and is interposed between the lifter 29 and the accommodating recess 25. The elastic member 33 is formed of, for example, a coil spring.

[0048] The lifter 29 protrudes retractably from the upper surface 18 due to the biasing force of the elastic member 33, that is, the upper surfaces 30 of the ridge portions 29aa and 29ab protrude from the flush state with the upper surface 18 as shown in Fig. 4 as shown in Fig. 3 and Fig. 5. When the upper surfaces of the ridge portions 29aa and 29ab protrude from the upper surface 18 of the lower mold 17a, contact between the adhesive G and the upper surface 18 is avoided as shown in Fig. 3.

[0049] 3 and 5, the lifter 29 rises from the lower die 17a of the lift stage 17 to support the lower surface WL of the upstream planned punching range Ru of the steel sheet W, thereby allowing the steel sheet W to be fed. This feeding allows the upstream planned punching range Ru to be positioned above the die 14a of the outer periphery punching stage 13.

[0050] Furthermore, the lifter 29 is pressed by the stripper 22 and retreats to the lower die 17a of the lift stage 17 against the biasing force of the elastic member 33. This retreat causes the steel sheet W to descend onto the upper surfaces 18 on the lower dies 17a and 13a of the lift stage 17 and the outer peripheral punching stage 13, respectively, as shown in FIG.

[0051] Therefore, when the upper die 3 descends while the steel sheet W is fed sequentially in the X direction, the punches 19 and 21 on the inner peripheral punching stage 11 and the outer peripheral punching stage 13 of the punching device 1 both descend in the Z direction. This descent causes the stripper 22 on the upper die 3 side to press down on the steel sheet W, and then the punches 19 and 21 begin to function. In the adhesive application stage 15, the adhesive application device 23 begins to function, and in the lift stage 17, the lifter 29 descends against the biasing force of the elastic member 33. As a result, core pieces 2 are continuously punched out of the strip-shaped steel sheet W and are stacked sequentially.

[0052] [Operation etc.] Fig. 6 is a block diagram showing the flow of the punching device of Fig. 1. Fig. 7 is a plan view showing a steel plate punched by the punching device of Fig. 1 together with the application position of adhesive.

[0053] In the punching device 1, the upper die 3 descends while the steel sheet W is fed sequentially in the X direction, and the inner peripheral punching stage 11, adhesive application stage 15, and outer peripheral punching stage 13 function. The lift stage 17 functions when the steel sheet W is fed in the X direction, and the lifter 29 rises as described above, enabling feeding that avoids the adhesive G.

[0054] 1, 2, and 6, inner peripheral punching is performed by a punch 19 in the inner peripheral punching stage 7, and slots 35 and the like are formed as inner peripheral punched portions 36 within the planned punching range R as shown in Fig. 7. The inner peripheral punched portions 36 refer to the inner peripheral punched portions within the planned punching range R, including the slots 35.

[0055] At the adhesive application stage 15, an adhesive application operation is performed, and adhesive G is applied in dots circumferentially by an adhesive application device 23 within the circular planned punching range R of the fed strip-shaped steel sheet W, as shown in Figure 7. This application results in adhesive G being arranged at equal intervals circumferentially near the base of each tooth 38. Note that adhesive G may also be applied to the tip of the tooth 38.

[0056] The lift stage 17 is idled. That is, the planned punching range R waits on the lift stage 17 as the planned upstream punching range Ru. When the planned upstream punching range Ru moves onto the lift stage 17, a lifter 29 is raised so as to be retractable from the lower die 17a of the lift stage 17. The steel sheet W slides on this lifter 29. At this time, the adhesive G in the planned upstream punching range Ru is avoided by the groove portion 29b of the lifter 29.

[0057] Meanwhile, the downstream planned punching range R, which was waiting in advance on the lift stage 17, is positioned on the die 14a of the outer peripheral punching stage 13 as the steel plate W slides on the lifter 29 of the steel plate W.

[0058] When the steel sheet W is fed, the adhesive G passes between the grooves 29b as shown in FIG. 3, so that the steel sheet W is allowed to be fed on the lifter 29.

[0059] When the steel sheet W is fed so that the downstream planned punching range R is positioned above the die 14a of the outer peripheral punching stage 13, the upper die 3 descends. At this time, as the stripper 22 presses down the steel sheet W, the lifter 29 descends against the biasing force of the elastic member 33.

[0060] When the lifter 29 is allowed to descend, the steel sheet W descends onto the upper surfaces 18 of the lower dies 17a and 13a of the lift stage 17 and the outer periphery punching stage 13, as shown in FIG.

[0061] At this time, in the lift stage 17, the adhesive G in the upstream planned punching range Ru is allowed to escape into the relief recess 27 as shown in Figure 4, while the steel sheet W is received on the upper surface 18. In this state, the upstream planned punching range Ru waits until the next feeding.

[0062] In the outer periphery punching stage 13, outer periphery punching is performed by a punch 21. That is, the intended punching range R is punched out as a core piece 2 (punched piece), and is held in a squeeze 14b as shown in Figure 1. Through this holding, a plurality of core pieces 2 are stacked while being bonded with adhesive G. At this time, the steel sheet W is also received on the upper surface 18 of the adjacent lift stage 17, so punching can be performed with high precision.

[0063] As described above, in the punching device 1 of this embodiment, the upstream planned punching range Ru of the steel plate W is supported on the lift stage 17 by a lifter 29 that protrudes retractably from the upper surface 18, which is a fixed side receiving surface having an escape portion 20 for the adhesive G.

[0064] Therefore, the punching device 1 can suppress sagging of the upstream planned punching area Ru. Therefore, there is no need to provide a separate member for receiving the upstream planned punching area Ru to which the adhesive G is applied in the punching device 1, and the structure of the punching device 1 can be simplified. In addition, since the lifter 29 is retractably protruded from the upper surface 18 of the lower die 17a, the structure of the punching device 1 can be further simplified. During punching at the outer peripheral punching stage 13, the steel sheet W can be reliably received on the upper surface 18 of the adjacent lift stage 17 while the adhesive G escapes, improving punching accuracy.

[0065] In this embodiment, the lifters 29 support the vicinity of the center of the intended punching range R, where the spacing of the adhesive G in the Y direction is relatively wide. Therefore, even if the adhesive G is applied evenly in the circumferential direction, the lifters 29 can be prevented from interfering. As a result, the adhesive strength between the core pieces 2 can be made uniform in the circumferential direction.

[0066] Furthermore, by the lifter 29 supporting the vicinity of the center of the intended punching range R, sagging of the intended punching range R can be more reliably suppressed.

[0067] Furthermore, the planned punching range R has an inner peripheral punching portion 36, and the lifter 29 supports the lower surface WL of the upstream planned punching range Ru so that it crosses in the feed direction to the inner peripheral punching portion 36. Therefore, the punching device 1 of this embodiment can reliably support the lower surface WL and suppress sagging even in the planned punching range R having the inner peripheral punching portion 36.

[0068] The lifter 29 is longer in the X direction than the diameter of the inner peripheral cutout 36. Therefore, the lifter 29 reliably supports the lower surface WL near the center of the intended punching range R where the inner peripheral cutout 36 is located, thereby preventing sagging.

[0069] [Modifications] Fig. 8 is a schematic plan view showing a modification of the lifter. Fig. 9 is a schematic plan view showing another modification of the lifter. The basic configuration of the modification is the same as that of the above-described embodiment, and the configuration of the modification that is the same as or corresponds to that of the embodiment is indicated by the same reference numeral, and redundant explanations will be omitted.

[0070] 8, both end portions 29c of the lifter 29 in the X direction are formed in a convex arc shape that convex outward in the X direction in a plan view. Accordingly, both end portions of the installation recess 25 of the lower mold 17a in the X direction are also formed in a convex arc shape in a plan view. However, both end portions of the installation recess 25 in the X direction do not necessarily need to be formed in a convex arc shape, and may have any shape that allows the lifter 29 to be raised and lowered.

[0071] The convex arc shape of the lifter 29 in the X direction allows the support range of the steel sheet W to be set relatively longer than that of a rectangular lifter 29 .

[0072] 9, both end portions 29c in the X direction of the lifter 29 and the accommodating recess 25 are formed in a concave arc shape that is concave inward in the X direction in a plan view. However, both end portions in the X direction of the accommodating recess 25 of the lower mold 17a do not necessarily need to be set in a concave arc shape.

[0073] The concave arc shape of the lifter 29 in the X direction makes it possible to avoid interference with members upstream and downstream in the X direction, or to eliminate the need for additional clearance for the mating members.

[0074] Instead of the convex or concave arc shapes of both end portions 29c of the lifter 29, one end portion in the X direction may be set to a convex or concave arc shape. In this case, the other end portion of the lifter 29 may be configured to be linear as in Example 1. Also, one end portion of the lifter 29 in the X direction may be set to a convex arc shape, and the other end portion may be set to a concave arc shape.

[0075] Furthermore, a gradient may be set across the upper surface of the upstream end of the lifter 29 in the X direction. In this case, a guide structure may be provided to prevent the upstream end of the lifter 29 in the X direction from interfering with the slot 35 cut out in the shape of the intended punching range R when the steel sheet W is fed.

[0076] Fig. 10 is a schematic cross-sectional view showing yet another modified example of the lifter. Fig. 11 is a schematic cross-sectional view showing yet another modified example of the lifter. The basic configuration of the modified example is the same as that of the above embodiment, and the same or corresponding configuration of the modified example is indicated by the same reference numeral, and redundant explanations will be omitted.

[0077] In the modification shown in Fig. 10, the Y-direction side surfaces of the protruding ribs 29aa and 29ab of the lifter 29 are formed in a stepped shape in which the width in the Y direction gradually decreases toward the tip in the Z direction. In the modification shown in Fig. 11, the bases of both Y-direction side surfaces of the protruding ribs 29aa and 29ab of the lifter 29 are provided with a gradient in which the width in the Y direction gradually decreases toward the tip in the Z direction.

[0078] 10 and 11, one of the protruding strips 29ab is omitted.

[0079] In this modified example, the width in the Y direction at the Z-direction tips 30 of the ridge portions 29aa and 29ab can be reduced in accordance with the Y-direction dimension between the adhesive G. Moreover, the support rigidity of the ridge portions 29aa and 29ab and the entire lifter 29 can be maintained.

[0080] 2 Core piece (punched piece) 13 Outer peripheral punching stage (punching stage) 15 Adhesive application stage 17 Lift stage 20 Relief portion 23 Adhesive application device 27 Relief recess 29 Lifter 29a Convex ridge portion 29b Concave ridge portion 36 Inner peripheral punching portion G Adhesive R Planned punching range Ru Planned upstream punching range W Steel plate

Claims

1. An adhesive application stage that sequentially applies dots of adhesive to the underside of a plurality of planned punching areas having a circular outer shape of a strip-shaped steel plate; a punching stage that sequentially punches out the plurality of planned punching areas in accordance with the feed of the steel plate to laminate a plurality of punched pieces with the adhesive; and a lift stage that is provided between the adhesive application stage and the punching stage, that supports the steel plate from the underside while avoiding the adhesive when the steel plate is fed, and that keeps an upstream planned punching area, which is a planned punching area located upstream of the planned punching area, on standby when the planned punching area is punched out at the punching stage, wherein the lift stage comprises: a fixed-side receiving surface that receives the underside of the steel plate when the planned punching area is punched out at the punching stage; an escape section that escapes contact between the fixed-side receiving surface and the adhesive applied to the underside of the upstream planned punching area; and a lifter that protrudes so as to be able to retreat relative to the fixed-side receiving surface. the lifter supports the lower surface of the upstream intended punching range by protruding at a position that does not overlap with the adhesive in the feed direction of the steel plate, and enables the steel plate to be received by the fixed-side receiving surface by retracting.

2. A punching device according to claim 1, wherein the lifter is provided with a plurality of convex ridges along the feed direction that support the lower surface of the upstream intended punching range, and concave ridges that avoid the adhesive between the convex ridges.

3. A punching device according to claim 1 or 2, wherein the lifter is arranged on the central side of the upstream intended punching range in the width direction of the steel plate, and the escape portion has an escape recess that allows the adhesive to escape on the outer side of the lifter in the width direction.

4. A punching device according to claim 1 or 2, wherein the intended punching range comprises an inner peripheral punching section, and the lifter supports the underside of the upstream intended punching range so as to cross over to the inner peripheral punching section in the feed direction.

5. A punching device according to claim 4, wherein the lifter is longer in the feed direction than the diameter of the inner peripheral punching portion.

6. A punching device according to claim 1 or 2, wherein the lift stage is adjacent to the adhesive application stage downstream in the feed direction and adjacent to the punching stage upstream in the feed direction.

7. A lift stage for holding an upstream planned punching range, which is a planned punching range located upstream of a planned punching range, when punching from a strip-shaped steel plate in a planned punching range having a circular outer shape and a circular dotted application of adhesive on the underside, the lift stage comprising: a fixed-side receiving surface that receives the underside of the steel plate when punching the planned punching range; an escape section that avoids contact between the fixed-side receiving surface and the adhesive applied to the underside of the upstream planned punching range; and a lifter that protrudes and can be retracted from the fixed-side receiving surface, wherein the lifter supports the underside of the upstream planned punching range at a position that does not overlap with the adhesive in the feed direction of the steel plate by protruding, and enables the steel plate to be received by the fixed-side receiving surface by retracting.

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