Stamping die and stamping forming method

Abstract

The present invention provides a stamping die and a stamping forming method, wherein the stamping die comprises an upper die frame, a lower die frame, a punch and a die, a punch step portion is formed on the punch forming surface, a die step portion is formed on the die forming surface, an inner rounded corner punch cooperates with an inner rounded corner die to form an inner rounded corner, an outer rounded corner punch cooperates with an outer rounded corner die to form an outer rounded corner, the die step portion cooperates with the punch step portion to form an arc-shaped step portion, and the corner width of the punch step portion gradually increases from both sides to the center. The corner width of the punch step portion on the punch of the stamping die of the present application gradually increases from both sides to the center, which will accelerate the flow of the bent product to the center of the corner of the above-mentioned forming space, and can effectively avoid extrusion and stacking of materials, thereby reducing the probability of product deformation caused by local stress caused by extrusion and stacking of materials, reducing product defective rate, and facilitating product assembly.

Description

Technical Field

[0001] The invention relates to the technical field of molds, in particular to a stamping mold for forming a stepped fillet of a sheet metal product and a stamping forming method thereof. Background Art

[0002] At present, some sheet metal products 1, such as the side panel of the outdoor unit of the air conditioner, generally have a step structure a formed on the top edge of the product 1 according to structural requirements in order to meet the requirements of the assembly gap between the side panel and the top cover of the outdoor unit, such as Figures 1 to 4 As shown, according to structural requirements, the step needs to be bent into a fillet, and accordingly, a step-shaped fillet b is formed at the step structure a, and the fillet includes an inner fillet b1 with a smaller bending radius and an outer fillet b2 with a larger bending radius. An arc-shaped step difference portion b3 is formed between the outer fillet b2 and the inner fillet b1, and the arc-shaped step difference portion b3 connects the outer fillet b2 and the inner fillet b1 as a whole. During assembly, the inner fillet b1 is attached to the inner side of the fillet of the top cover to play a matching and fixing role, and the outer fillet b2 is usually an appearance area.

[0003] The rounded corner bending of products with step structure a is different from the rounded corner bending of flat products. Before the rounded corner bending of flat products, since the product is a uniform flat product, there will be no local excess material during the bending process. During the rounded corner bending process, the material in the formed area can be evenly bent and deformed to the final shape. However, the rounded corner bending of products with step structure a has different arc lengths of the inner and outer fillets, and the arc length corresponding to the inner fillet is smaller than the arc length corresponding to the outer fillet. After forming, the inner fillet will bend and wrinkle. The local extrusion and stacking stress will become stronger and cause deformation at the step, resulting in poor forming of the entire bending angle and arc length, which will affect the assembly and appearance of the product.

[0004] In the stamping die industry, the molding control of uneven and irregular structures is a difficult problem in the industry. Irregular structures often cause different expansion coefficients or material flow degrees in connected areas, which in turn affects local extrusion, stacking or thinning, causing products to wrinkle, twist, deform, or even break.

[0005] At present, the commonly used method for rounded corner bending of products with step structure a in the industry is to limit the forming area of ​​the inner fillet, that is, to make it as small as possible, and at the same time to apply strong pressure so that the excess material is forcibly flattened in the stacking area to reduce the impact of material stacking. This method limits the shape of the inner fillet, and there are many defects in the product after forming. The degree of material stacking is uncontrollable, the bending stress at the break is too strong, affecting the bending angle, and defects such as poor fillet forming and deformation are difficult to eliminate. Summary of the invention

[0006] The present invention provides a stamping die and a stamping forming method, which can solve the problems in the prior art that when a product with a step structure is rounded and bent, the inner fillet is easily squeezed out, resulting in poor forming, local stress concentration, resulting in deformation, and affecting product assembly.

[0007] In some embodiments of the present application, a stamping die is provided for bending and forming a stepped fillet on a product, wherein the stepped fillet includes an inner fillet and an outer fillet, and the inner fillet and the outer fillet are connected as a whole by an arc-shaped step difference portion; the stamping die includes:

[0008] An upper mold frame and a lower mold frame are arranged opposite to each other;

[0009] A punch, which is fixed on the upper die frame, comprises an inner rounded corner punch and an outer rounded corner punch arranged adjacent to each other, and a punch step portion is formed on the molding surface of the punch;

[0010] A concave die, which is fixed on the lower die frame, comprises an inner rounded corner concave die and an outer rounded corner concave die arranged adjacent to each other, a concave die step difference portion is formed on the molding surface of the concave die, and the concave die step difference portion is adapted to the convex die step difference portion;

[0011] The inner fillet punch cooperates with the inner fillet die to form the inner fillet, the outer fillet punch cooperates with the outer fillet die to form the outer fillet, the die step portion cooperates with the punch step portion to form the arc-shaped step portion, and the corner width of the punch step portion gradually increases from both sides to the center.

[0012] In some embodiments of the present application, the width value corresponding to the minimum width of the corner of the punch difference portion is W min , the W min It is equal to the step structure width W before the step-shaped fillet bending forming, and the width value corresponding to the maximum corner width of the punch difference part is W max , the W max The difference between the step structure width W corresponding to the step-shaped fillet bending forming and the step structure width W is △W, and △W=0.2W. The width of the straight sides of the punch difference part is equal to the step structure width W corresponding to the step-shaped fillet bending forming and the step structure width W corresponding to the step-shaped fillet bending forming and the step structure width W.

[0013] In some embodiments of the present application, the die also includes a stress adjustment component, which is arranged adjacent to the outer corner die and the inner corner die, and the stress adjustment component is arranged at two locations and corresponds one to one to the straight edges on both sides of the step-shaped fillet. The stress adjustment component includes a first part corresponding to the inner corner and a second part corresponding to the outer corner. The first part protrudes toward the side where the punch is located compared to the second part, and the protruding height is greater than the step structure width W corresponding to the step-shaped fillet before bending and forming. The first part includes a first inclined portion for participating in the forming of the side straight edge of the inner corner and a first planar support portion facing the side where the inner corner punch is located, and the second portion includes a second inclined portion for participating in the forming of the side straight edge of the outer corner and a second planar support portion facing the side where the outer corner punch is located.

[0014] In some embodiments of the present application, the first planar support portion transitions to the first inclined portion in a circular arc, and the second planar support portion transitions to the second inclined portion in a circular arc.

[0015] In some embodiments of the present application, the straight-edge forming surfaces on both sides of the inner rounded corner punch are perpendicular to the punch step portion, the corner forming surface of the inner rounded corner punch is inclined relative to the punch step portion toward the side away from the inner rounded corner die, and the corner forming surface of the inner rounded corner die has a slope that matches the corner forming surface of the inner rounded corner punch.

[0016] In some embodiments of the present application, the outer rounded corner die includes an outer rounded corner die body and an extension section fitted with the outer rounded corner die body, the extension section has an outer rounded corner forming surface adapted to the outer rounded corner die, the die step portion is formed on the inner rounded corner die, the extension section is fixedly connected to the inner rounded corner die as a whole and is located between the outer rounded corner die body and the die step portion.

[0017] In some embodiments of the present application, the width of the extension section is 3-10 mm, and the extension section is integrally formed on the inner fillet die.

[0018] In some embodiments of the present application, the angle between the straight-side forming surfaces on both sides of the inner fillet punch has an over-folding angle, and the inner fillet die has an over-folding angle equal to that of the inner fillet punch.

[0019] In some embodiments of the present application, the outer rounded corner punch is an integral punch structure or is composed of a plurality of outer rounded corner sub-punches arranged along the length direction of the outer rounded corner of the product, and the angle between the straight-edge forming surfaces on both sides thereof has an over-folding angle, and along the length direction of the outer rounded corner of the product, the over-folding angles at both ends of the outer rounded corner punch are smaller than the over-folding angle of the middle section, and at both ends of the outer rounded corner punch, the over-folding angle at the end where the punch difference portion is located is smaller than the over-folding angle at the other end of the outer rounded corner punch; the outer rounded corner concave mold has an over-folding angle equal to that of the outer rounded corner punch.

[0020] In some embodiments of the present application, a stamping forming method based on the above-mentioned stamping die is also proposed, comprising the following steps:

[0021] A product is provided, wherein a step structure is formed on the product, and a flow material filling gap is reserved on the edge of the product portion corresponding to the inner fillet;

[0022] Positioning the product on the die, wherein the step structure corresponds to the step difference portion of the die;

[0023] The upper die frame drives the punch downward, and cooperates with the die to stamp and form the stepped fillet.

[0024] Compared with the prior art, the corner width of the punch section on the punch of the stamping die of the present application gradually increases from both sides to the center, and correspondingly, the corner width of the die section on the die gradually increases from both sides to the center, that is, the corner width of the forming space surrounded by the punch section and the die section for forming the arc-shaped section gradually increases from both sides to the center. When the punch and the die cooperate to form a stepped fillet, the punch section and the die section will cause the material flow of the bent product to accelerate to the center of the corner of the above-mentioned forming space, that is, the lowest corner. Position, when the stamping die of the present application is used to form a stepped fillet on the product, it is only necessary to reserve a flow filling gap on the edge of the part corresponding to the inner fillet corner on the step structure in addition to the step structure required for forming the stepped fillet before forming, so that during the forming process, the punch and die break parts cooperate to guide the excess material flow into the reserved flow filling gap, which can effectively avoid material extrusion and material piling, thereby reducing the probability of product deformation caused by local stress caused by extrusion and material piling, reducing product defective rate, and facilitating product assembly. At the same time, the forming method of bending and forming step-shaped fillets using the stamping die of the present invention is simple and smooth, with high forming efficiency and high forming quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0026] Figure 1 This is a three-dimensional diagram of the product structure before the step-shaped fillet is formed;

[0027] Figure 2 yes Figure 1 A magnified view of the structure of part A;

[0028] Figure 3 This is a three-dimensional diagram of the product structure after step-shaped fillet molding;

[0029] Figure 4 yes Figure 3 A magnified view of the structure of part B;

[0030] Figure 5 It is a schematic diagram of the structure of the stamping die in the embodiment of the present application;

[0031] Figure 6 It is a stereogram of the male mold in the embodiment of the present application;

[0032] Figure 7 yes Figure 6 Enlarged view of part C;

[0033] Figure 8 yes Figure 6 Right view of;

[0034] Fig. 9 It is a stereogram of the concave mold in the embodiment of the present application;

[0035] Fig.10 yes Fig. 9 A magnified view of the D portion;

[0036] Fig.11 is a three-dimensional diagram of the inner fillet concave mold in the embodiment of the present application;

[0037] Fig.12 is a three-dimensional diagram of a stress adjustment component in an embodiment of the present application;

[0038] Fig.13 It is a three-dimensional diagram of the product placed on the stamping die before the step-shaped fillet is formed in the mold opening state in the embodiment of the present application;

[0039] Fig.14 yes Fig.13 Front view of the product on the die before forming the middle step fillet;

[0040] Fig.15 yes Fig.14 A magnified view of part E;

[0041] Fig.16 It is a three-dimensional diagram of the product and the stamping die in the mold-forming state in the embodiment of the present application;

[0042] Fig.17 yes Fig.16 Magnified view of part F;

[0043] Fig.18 yes Fig.16 Right view of;

[0044] Fig.19 yes Fig.18 GG section view;

[0045] Fig. 20 yes Fig.19 Enlarged view of the H part.

[0046] 1-product; a-step structure; a1-flow material filling gap; b-step fillet; b1-inner fillet; b2-outer fillet; b3-arc-shaped break;

[0047] 100-upper mold frame; 200-lower mold frame; 210-product positioning structure; 300-punch; 310-inner rounded corner punch; 311-side straight edge molding surface; 312-corner molding surface; 320-outer rounded corner punch; 330-punch step difference portion; 331-straight edge portion; 332-corner; 400-die; 410-inner rounded corner die; 411-inner rounded corner die corner molding surface; 420-outer rounded corner die; 421-outer rounded corner die body; 422-extension section; 430-die step difference portion; 440-stress adjustment component; 441-first part; 441A-first inclined portion; 441B-first plane support portion; 442-second part; 442A-second inclined portion; 442B-second plane support portion; 443-L-shaped positioning portion. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0049] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0050] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the feature. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0051] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0052] Reference Figures 1 to 20 In this embodiment, a stamping die is used to bend and form a stepped fillet b on a product 1. In this embodiment, the product 1 is Figures 1 to 4 As shown in the outdoor unit side panel, before the step-shaped fillet b is bent and formed, a step structure a has been formed on the product 1 in the previous process, and a flow material filling gap a1 has been formed at the edge of the step structure a. According to structural requirements, the step needs to be bent and formed into a fillet, and accordingly, a step-shaped fillet b is formed at the step structure a. The step-shaped fillet b includes an inner fillet b1 and an outer fillet b2. The bending radius of the inner fillet b1 is smaller than the bending radius of the outer fillet b2, and the inner fillet b1 and the outer fillet b2 are connected as a whole by an arc-shaped step difference portion b3.

[0053] In this embodiment, the stamping die includes an upper die frame 100 and a lower die frame 200 which are arranged relatively to each other, and also includes a punch 300 and a die 400. The punch 300 is fixed on the upper die frame 100 to realize the mold opening and closing actions under the drive of the upper die frame 100. The punch 300 includes an inner rounded corner punch 310 and an outer rounded corner punch 320 which are arranged adjacent to each other. One end face of the inner rounded corner punch 310 is in contact with one end face of the outer rounded corner punch 320. 00 is formed with a punch step portion 330; the die 400 is fixed on the lower die frame 200, and includes an inner rounded corner die 410 and an outer rounded corner die 420 arranged adjacent to each other, and a die step portion 430 is formed on the molding surface of the die 400, and the die step portion 430 is adapted to the punch step portion 330, and a product positioning structure 210 is provided on the lower die frame 200 to position the product 1 when the product 1 is placed on the die 400.

[0054] The inner fillet punch 310 cooperates with the inner fillet die 410 to form the inner fillet b1, the outer fillet punch 320 cooperates with the outer fillet die 420 to form the outer fillet b2, and the die step difference portion 430 cooperates with the punch step difference portion 330 to form the arc step difference portion b3. Figures 6 to 8 As shown, the punch section 330 includes straight edge portions 331 on both sides and a corner portion 332 in the middle, wherein the corner portion 332 ( Figure 8 The width W of the portion within the dotted line frame) gradually increases from both sides to the center (i.e., the lowest position of the corner 332), that is, the width is largest at the lowest position of the corner, and the width on both sides is small; since the die step difference portion 430 is adapted to the punch step difference portion 330, correspondingly, the corner width of the die step difference portion 430 also gradually increases from both sides to the center.

[0055] Since the punch step difference portion 330 and the die step difference portion 430 enclose a forming space for forming the arc-shaped step difference portion b3, correspondingly, the corner width of the forming space is also gradually increased from both sides to the center. When the punch 300 and the die 400 cooperate to form the step-shaped fillet b, the punch step difference portion 330 and the die step difference portion 430 will cause the bent product flow to accelerate to the center of the corner of the forming space, that is, the lowest position of the corner. When the stamping die of this embodiment is used to form the step-shaped fillet b on the product 1, it is only necessary to remove the step required for forming the step-shaped fillet b on the product 1 before forming. In addition to structure a, a flow filling gap a1 is reserved on the edge of the step structure a corresponding to the corner of the inner fillet b1, so that during the molding process, the punch difference portion 330 and the die difference portion 430 cooperate to guide the excess material flow into the reserved flow filling gap a1, so that the flow filling gap a1 on the inner fillet b1 after molding is basically filled with the material flow, and the flow filling gap a1 basically disappears, as shown in the figure, and it cannot be applied for. It can effectively avoid extrusion and stacking of materials, thereby reducing the probability of product deformation caused by local stress caused by extrusion and stacking of materials, reducing product defective rate, and facilitating product assembly.

[0056] The width value corresponding to the minimum width of the corner 332 of the punch section 330 is W min , the maximum width is W max , W min Equal to the width w of the step structure a before the step fillet b is bent, W max The difference between the width w of the step structure a corresponding to the step-shaped fillet b before bending is △W, and △W=0.2w. The width of the straight edge portions 331 on both sides of the punch step difference portion 330 is equal to the width w of the step structure a corresponding to the step-shaped fillet b before bending. Taking the width of the step structure a as 5mm as an example, the width value W corresponding to the smallest width of the corner 332 of the punch step difference portion 330 is min The width of the straight edge portions 331 on both sides of the punch section 330 is also 5 mm. The width of the corner portion 332 of the punch section 330 at the maximum width corresponds to the width value W max If the width of the step structure a is 10 mm, the width value W corresponding to the minimum width of the corner 332 of the punch break portion 330 is min The width of the straight edge portions 331 on both sides of the punch section 330 is also 10 mm. The width of the corner portion 332 of the punch section 330 at the maximum width corresponds to the width value W max It is 12mm.

[0057] When the step-shaped fillet b is formed by stamping and bending, due to the different radii of the inner fillet b1 and the outer fillet b2, the step structure a is bent and deformed along two layers of arc trajectories of different sizes. The inner fillet b1 is located inside the outer fillet b2 and has a small radius. The corresponding part forming stress of the product is greater than the product forming stress of the outer fillet b2. Excessive local stress will easily cause deformation. In order to further avoid deformation caused by excessive local stress at the inner fillet b1, the die 400 in this embodiment also includes a stress adjustment component 440, such as Fig. 9 , Fig.10 and Fig.12As shown, the stress adjustment component 440 is specifically a block structure, which is arranged adjacent to the outer rounded corner die 420 and the inner rounded corner die 410, and is fixedly connected to the outer rounded corner die 420 and the inner rounded corner die 410 as a whole. Two stress adjustment components 440 are provided and correspond one to one with the straight edges of both sides of the stepped fillet b, that is, one is provided on each side of the stepped fillet b, the stress adjustment component 440 includes a first portion 441 corresponding to the inner fillet b1 and a second portion 442 corresponding to the outer fillet b2, the first portion 441 protrudes toward the side where the punch 300 is located compared with the second portion 442, that is, the first portion 441 is higher than the second portion 442, and the protruding height h is greater than the width W of the step structure a corresponding to the stepped fillet b before bending and forming, preferably about 4 mm more than the width W of the step structure a; the first portion 441 includes a first inclined portion 441A for participating in the forming of the side straight edge of the inner fillet b1 and a first planar support portion 441B facing the side where the inner fillet punch 310 is located, and correspondingly, the second portion 442 includes a second inclined portion 442A for participating in the forming of the side straight edge of the outer fillet b2 and a second planar support portion 442B facing the side where the outer fillet punch 320 is located.

[0058] By setting the stress adjustment component 440, since the first part 441 thereof protrudes toward the side where the punch is located compared to the second part 442, and the protruding height is greater than the step structure width W corresponding to the step fillet b before bending and forming, in the initial stage of forming, Figure 1 When the product 1 before the step-shaped fillet b is placed in place on the die 400, as shown in FIG. Figures 13 to 15 As shown, the product part corresponding to the inner fillet b1 is supported on the first plane support part 441B, while the product part corresponding to the outer fillet b2 has not yet contacted the second plane support part 442B, and there is a gap between the two. Then, when the punch 300 moves downward with the upper mold frame 100 to close the mold, the inner fillet punch 310 first contacts the product part corresponding to the inner fillet b1, and the inner fillet punch 310 cooperates with the first part 441 of the stress adjustment block to make the product part corresponding to the inner fillet b1 be force-formed first to release some bending stress, and the product part corresponding to the outer fillet b2 is force-formed later. The stress of the arc-shaped difference part b3 between the inner and outer fillets b2 is balanced by the order of force forming, so that the force is balanced when the product is bent as a whole to prevent deformation caused by excessive local stress.

[0059] Furthermore, the first planar support portion 441B and the first inclined portion 441A have an arc transition, and the second planar support portion 442B and the second inclined portion 442A have an arc transition, so as to avoid the presence of sharp parts that may damage the product surface during bending. Fig.12 , Fig.16 and Fig.17As shown, the stress adjustment component 440 also has an L-shaped positioning portion 443, which is located below the first portion 441 and the second portion 442. When it is installed on the die 400, the L-shaped positioning portion 443 can fit with the top and side surfaces of the die 400, thereby pre-positioning the installation of the stress adjustment component 440 and improving the mold assembly efficiency.

[0060] Since the inner fillet b1 and the outer fillet b2 have straight sides and a corner in the middle, accordingly, the molding surfaces of the inner fillet punch 310 and the inner fillet die 410 include both side straight-side molding surfaces and corner molding surfaces, and the molding surfaces of the outer fillet punch 320 and the outer fillet die 420 also include both side straight-side molding surfaces 311 and corner molding surfaces. The two side straight-side molding surfaces 311 of the inner fillet punch 310 are perpendicular to the punch step 330, and its corner molding surface 312 is inclined relative to the punch step 330 toward the side away from the inner fillet die 410. In this embodiment, it is inclined upward, that is, the corner molding surface 312 of the inner fillet punch 310 is an upwardly inclined inclined surface, such as Figure 7 and Figure 8 As shown, correspondingly, the corner molding surface 411 of the inner fillet die has a slope that matches the corner molding surface 312 of the inner fillet punch 310, so that the corner of the inner fillet b1 has an upward slope after molding, which can serve as an assembly guide when the product 1 is assembled.

[0061] For the die 400, if Figures 9 to 11 As shown, the outer rounded corner die 420 includes an outer rounded corner die body 421 and an extension section 422 fitted with the outer rounded corner die body 421, the extension section 422 has an outer rounded corner forming surface adapted to the outer rounded corner die body 421, and the extension section 422 and the outer rounded corner die body 421 together constitute the outer rounded corner die 420, the die step portion 430 is formed on the inner rounded corner die 410, the extension section 422 is fixedly connected to the inner rounded corner die 410 as a whole and is located between the outer rounded corner die body 421 and the die step portion 430. The extension section 422 extends toward the side where the outer fillet die 420 is located, and participates in the forming of the outer fillet b2 as a part of the outer fillet die 420. At the same time, the extension section 422 is also fixedly connected to the inner fillet die 410 as a whole, so as to protect the root of the stepped fillet b, that is, the root of the inner fillet b1 and the root of the outer fillet b2 connected by the step connection part, so as to avoid uneven forming of the fillet root and affect the stability of the forming size.

[0062] Furthermore, the width of the extension section 422 l The preferred width is 3-10 mm, that is, it covers the outer fillet b2 area with a width of 3-10 mm. The extension section 422 is integrally formed on the inner fillet die 410 , that is, it is an integrally formed structure with the inner fillet die 410 .

[0063] for Figures 6 to 8 The inner fillet punch 310 has an included angle between its two side straight edge forming surfaces 311 which is set as an over-folding angle according to the rebound coefficient of the product 1. The included angle between the two side straight edge forming surfaces 311 of the inner fillet punch 310 has an over-folding angle. Correspondingly, the inner fillet die 410 has an over-folding angle equal to that of the inner fillet punch 310 to ensure that the size of the inner fillet b1 after forming meets the design size.

[0064] for Figure 6 The rounded corner punch 320 in the embodiment can be an integral punch structure or composed of a plurality of rounded corner sub-punches arranged along the length direction of the product's rounded corner b2, wrapping the entire outer arc of the product 1. Similarly, the angle between the straight-edge forming surfaces on both sides of the rounded corner punch 320 is set to an over-folding angle according to the product's rebound coefficient, that is, it has an over-folding angle, and along the length direction of the product's rounded corner b2, the over-folding angle of the angle between the straight-edge forming surfaces on both sides of the rounded corner punch 320 at both ends is smaller than the over-folding angle of the middle section, and the over-folding angle at the end where the punch difference portion 330 is located at both ends of the rounded corner punch 320 is smaller than the over-folding angle at the other end of the rounded corner punch 320, and the different over-folding angles in adjacent areas are evenly transitioned to adapt to the stress rebound in different areas of the long strip product; accordingly, the rounded corner concave mold 420 has an over-folding angle equal to that of the rounded corner punch 320.

[0065] In this embodiment, a stamping forming method based on the above-mentioned stamping die is also proposed, comprising the following steps:

[0066] A product 1 is provided, on which a step structure a has been formed in a previous process, and a gap a1 for filling flow material has been processed and reserved on the edge of the product portion corresponding to the inner fillet b1 after forming;

[0067] The product 1 is placed on the die 400, and the product positioning structure 210 on the lower die frame 200 positions the product so that the position of the step structure a corresponds to the position of the die step difference portion 430, as shown in FIG. Figures 13 to 15 As shown;

[0068] The upper mold frame 100 drives the punch 300 downward, and cooperates with the die 400 to stamp out a step-shaped fillet b on the product 1. Figures 16 to 20 As shown;

[0069] The upper mold frame 100 drives the punch 300 upward to open the mold and take out the product.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A stamping die for bending and forming a stepped fillet on a product, wherein the stepped fillet comprises an inner fillet and an outer fillet, wherein the inner fillet and the outer fillet are connected as a whole by an arc-shaped step difference portion; characterized in that: The stamping die comprises: An upper mold frame and a lower mold frame are arranged opposite to each other; A punch, which is fixed on the upper die frame, comprises an inner rounded corner punch and an outer rounded corner punch arranged adjacent to each other, and a punch step portion is formed on the molding surface of the punch; A concave die, which is fixed on the lower die frame, comprises an inner rounded corner concave die and an outer rounded corner concave die arranged adjacent to each other, a concave die step difference portion is formed on the molding surface of the concave die, and the concave die step difference portion is adapted to the convex die step difference portion; The inner fillet punch cooperates with the inner fillet die to form the inner fillet, the outer fillet punch cooperates with the outer fillet die to form the outer fillet, the die step portion cooperates with the punch step portion to form the arc-shaped step portion, and the corner width of the punch step portion gradually increases from both sides to the center.

2. The stamping die according to claim 1, characterized in that: The width of the corner of the punch section where the width is the smallest is W. min , the W min It is equal to the step structure width W before the step-shaped fillet bending forming, and the width value corresponding to the maximum corner width of the punch difference part is W max , the W max The difference between the step structure width W corresponding to the step-shaped fillet bending forming and the step structure width W is △W, and △W=0.2W. The width of the straight sides of the punch difference part is equal to the step structure width W corresponding to the step-shaped fillet bending forming and the step structure width W corresponding to the step-shaped fillet bending forming and the step structure width W.

3. The stamping die according to claim 1, characterized in that: The die also includes a stress adjustment component, which is arranged at the adjacent parts of the outer fillet die and the inner fillet die. The stress adjustment component is arranged at two places and corresponds one to one with the straight edges on both sides of the step-shaped fillet. The stress adjustment component includes a first part corresponding to the inner fillet and a second part corresponding to the outer fillet. The first part protrudes toward the side where the punch is located compared to the second part, and the protruding height is greater than the corresponding step structure width W before the step-shaped fillet is bent and formed. The first part includes a first inclined portion for participating in the forming of the side straight edges of the inner fillet and a first planar support portion facing the side where the inner fillet punch is located. The second part includes a second inclined portion for participating in the forming of the side straight edges of the outer fillet and a second planar support portion facing the side where the outer fillet punch is located.

4. The stamping die according to claim 3, characterized in that: The first planar support portion transitions to the first inclined portion in an arc shape, and the second planar support portion transitions to the second inclined portion in an arc shape.

5. The stamping die according to claim 1, characterized in that: The straight-edge forming surfaces on both sides of the inner rounded corner punch are perpendicular to the punch step portion, and the corner forming surface of the inner rounded corner punch is inclined relative to the punch step portion toward the side away from the inner rounded corner die, and the corner forming surface of the inner rounded corner die has a slope that matches the corner forming surface of the inner rounded corner punch.

6. The stamping die according to claim 1, characterized in that: The outer rounded corner die comprises an outer rounded corner die body and an extension section fitted with the outer rounded corner die body, the extension section has an outer rounded corner forming surface adapted to the outer rounded corner die, the die step portion is formed on the inner rounded corner die, the extension section is fixedly connected to the inner rounded corner die as a whole and is located between the outer rounded corner die body and the die step portion.

7. The stamping die according to claim 6, characterized in that: The extension section has a width of 3-10 mm and is integrally formed on the fillet die.

8. The stamping die according to claim 1, characterized in that: The angle between the straight-side forming surfaces on both sides of the inner fillet punch has an over-folding angle, and the inner fillet concave mold has an over-folding angle equal to that of the inner fillet punch.

9. The stamping die according to claim 1, characterized in that: The outer rounded corner punch is an integral punch structure or is composed of a plurality of outer rounded corner sub-punches arranged along the length direction of the outer rounded corner of the product. The angle between the straight-edge forming surfaces on both sides has an over-folding angle, and along the length direction of the outer rounded corner of the product, the over-folding angles at both ends of the outer rounded corner punch are smaller than the over-folding angle of the middle section, and at both ends of the outer rounded corner punch, the over-folding angle at the end where the punch difference portion is located is smaller than the over-folding angle at the other end of the outer rounded corner punch; the outer rounded corner concave mold has an over-folding angle equal to that of the outer rounded corner punch.

10. A stamping method based on the stamping die according to any one of claims 1 to 9, characterized in that: The steps include: A product is provided, wherein a step structure is formed on the product, and a flow material filling gap is reserved on the edge of the product portion corresponding to the inner fillet; Positioning the product on the die, wherein the step structure corresponds to the step difference portion of the die; The upper die frame drives the punch downward, and cooperates with the concave die to stamp and form the stepped fillet.

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