Forming die for making a plug-in melt from a strip with a narrow path and method thereof

Abstract

The invention relates to a forming die for producing a strip with a web into a plug-in melt, comprising a lower die holder, an upper die holder, a forming die head designed to successively perform a web-pressing operation on the web of the strip with a web, a bending operation on the body and a folding operation on the ends of the strip, in lengthwise direction from a central pressing punch, during the lowering of the upper die holder relative to the lower die holder. The forming die according to the invention allows a forming operation on the strip with a web, compared to the prior art. The invention also relates to a method for producing a strip with a web into a plug-in melt using the forming die.

Description

Technical Field

[0001] This invention relates to the field of machining, and in particular to a forming mold for making a plug-in molten material from a strip with a narrow diameter, and a method for manufacturing the molten material of a plug-in fuse using the forming mold to process the strip with a narrow diameter. Background Technology

[0002] A fuse is a simple and effective protective electrical appliance, mainly used for overload and short-circuit protection. A fuse primarily consists of a fusible element and an insulating tube that houses the element. In use, the fusible element is connected in series with the circuit being protected. When a short-circuit fault occurs, the fusible element melts instantaneously, breaking the circuit and providing protection. The manufacturing process of the fusible element typically involves several steps in its formation, such as feeding, cutting, and unloading. However, in existing technologies, the fusible element forming process is usually performed separately in separate devices. This results in drawbacks such as large space requirements and low production efficiency due to the disordered distribution of these devices and the material handling between them.

[0003] As a solution, the inventors of this application have disclosed a forming mold for forming molten strip into a molten material for a fuse in Chinese Utility Model Patent CN 219899913U. This forming mold includes a lower mold base located below a lower die plate and an upper mold base located above a stripper back plate. The lower mold base has external guide posts extending vertically into the upper mold base on both sides. The upper mold base is configured to be guided vertically downward and upward relative to the lower mold base by means of external guide sleeves fixedly connected to it and fitted around the outer periphery of the external guide posts. The upper surface of the lower mold base also includes a pair of positioning elements, each positioned, for example, on either side of two cutting edges, to ensure that the molten strip is positioned on the upper surface of the lower mold base. Subsequently, the molten strip can be fed to the paired positioning members and ensured to be adapted to the positioning members in the width direction. The upper die base is guided by the outer guide post to press down and rise vertically relative to the lower die base, which will realize the sequential bending, trimming, folding and punching of the molten strip positioned by the paired positioning members. During the pressing, the predetermined gap between the fixed plate and the stripping back plate is gradually reduced by overcoming the elastic force of the pressure spring, and the sequential forming process of the molten strip can be realized, for example, by means of the combined action of the pressure spring housed in the pressure spring hole and the ejector spring located in the upper die base.

[0004] The inventors of this application have discovered that although the above-described molding die can integrate multiple sequential operation steps of forming molten strip into a molten body into a single die, thereby allowing the forming of molten strip into a molten body for fuses to be achieved using a single die, in practice, it has been found that the molding die using the above-described patented technology still has the following shortcomings:

[0005] 1. The processing object of the above-mentioned forming mold is a slender solid melt strip, which requires the forming mold to integrate multiple process steps such as bending, trimming, folding and punching narrow diameter operations in sequence. This makes the design of the forming mold itself complicated, the manufacturing process cumbersome and the cost still high.

[0006] 2. Traditional fuses mostly use bolt connections, thus limiting the degree of bending on both sides. With the development of the fuse industry, plug-in fuses have been proposed for different application environments. In this type of fuse, the fusible element includes a body and prongs bent outwards from both sides of the body for a considerable length. These paired prongs are then used for welding installation. The aforementioned forming mold cannot be used to manufacture this type of plug-in fuse with prongs.

[0007] Therefore, there is a technical need in the related technical field to provide a molding die with a simplified structure and wide applicability, which can improve manufacturing efficiency and reduce manufacturing costs. Summary of the Invention

[0008] Therefore, the objective of this invention is to provide a molding die and method that at least partially overcomes the disadvantages of the prior art.

[0009] According to one aspect of the invention, a forming die is provided for forming a plug-in melt from a strip with a narrow diameter, wherein the strip with the narrow diameter includes a plurality of narrow diameter portions spaced apart from each other between its opposite ends and a body portion located at adjacent narrow diameter portions, comprising: a lower die base, wherein the lower die base holds a die cavity, wherein the die cavity includes a top surface located at the uppermost position in a vertical direction and a plurality of bending grooves arranged alternately with these top surfaces; and an upper die base disposed vertically above the lower die base. The upper die base is configured to be guided vertically downward and upward relative to the lower die base via multiple outer guide posts biased by return springs; the forming die head located above the die cavity includes: a fixed plate fixedly connected to the upper die base; multiple blanking punches disposed therein, which are movable relative to the fixed plate in the height direction, wherein the blanking punches are designed to be at least partially aligned with the top surface in the height direction; multiple bending punches arranged alternately with these blanking punches, wherein the bending punches are designed to be at least partially aligned with the bending groove in the height direction; and a bending punch located on the outermost side; wherein the forming die is designed to, during the downward movement of the upper die base relative to the lower die base, successively perform blanking operations on the narrow portion of the narrow strip, bending operations on the body portion, and bending operations on both ends of the strip in the length direction from the central blanking punch to both sides.

[0010] Compared with the prior art, the molding die structure according to the present invention is significantly simplified and allows for molding operations on strips with narrow diameter sections. During molding, the pressing punch and the bending punch arranged alternately thereto are allowed to work sequentially to complete pressing and bending, ensuring that the narrow diameter section of the strip is not adversely affected during the molding operation, and ensuring that the quality of the resulting plug-in melt meets the technical requirements of the fuse.

[0011] According to a preferred aspect of the invention, the number of the blanking punches is the same as the number of top surfaces in the die, and the number of the bending punches is the same as the number of bending grooves.

[0012] According to a preferred aspect of the invention, it includes a centrally located first pressing punch that is closest to the top surface in the height direction and second, third, fourth, fifth and sixth pressing punches that are spaced apart in the length direction, wherein the distance of these pressing punches from the top surface gradually increases.

[0013] According to a preferred aspect of the invention, the invention further includes pairs of bending punches located on both sides of the first pressing punch along the length direction, wherein the height of the bending punches along the height direction is less than that of the first pressing punch, and pairs of bending punches respectively assigned to the second, third, fourth, fifth and sixth pressing punches along the length direction, wherein the height of these pairs of bending punches along the height direction is less than that of the second, third, fourth, fifth and sixth pressing punches to which they are assigned.

[0014] According to a preferred aspect of the invention, a spring fixing seat is further provided on the side of the upper die base facing away from the fixing plate, wherein the spring fixing seat is provided with a plurality of spring fixing holes, wherein a group of compression springs and pressure rods are provided in the spring fixing holes, wherein the group of compression springs and pressure rods are associated with the pressing punch, bending punch and folding punch.

[0015] According to a preferred aspect of the invention, the pair of bending punches are arranged at an angle relative to the pressing punch located therebetween, such that the pointed portion of the bending punch has a gap relative to the lowermost end of the pressing punch.

[0016] According to a preferred aspect of the invention, the bending groove is designed to have a depth and a side length, wherein the distance between the bending punch and the pressing punch is designed to be 0.9 to 1.1 times the side length of the bending groove to which it is attached.

[0017] According to a preferred aspect of the invention, the longitudinal axis of the bending punch is designed to have an angle of 3 to 5 degrees relative to the longitudinal axis of the pressing punch located therebetween.

[0018] According to another aspect of the present invention, a method for forming a plug-in melt from a strip with a narrow diameter using a forming die is also provided, wherein the forming die is the forming die described above, comprising the following steps: Step 1. Adjusting the position of the die along the length direction according to a strip with a narrow diameter of a selected length, such that the position of the narrow diameter portion of the strip with the narrow diameter corresponds one-to-one with the position of the top surface of the die, and wherein a plurality of body portions correspond one-to-one with the position of the bending groove of the die; Step 2. Moving the upper die holder and the forming die head downward, so that the centrally arranged pressure punch contacts the narrow diameter portion first and presses it against the top surface of the die; Step 3. Bending punches located on both sides of the centrally arranged pressure punch bend the body portions located at the bending groove of the die to form a V-shaped bend of the plug-in melt; Step 4. The second, third, fourth, fifth, and sixth blanking punches are successively used to contact the corresponding narrow sections and press them against the top surface of the die. Simultaneously, pairs of bending punches associated with the second, third, fourth, fifth, and sixth blanking punches are used to bend the body section located at the bending groove of the die to form multiple V-shaped bends of the plug-in melt; Step 5. The bending punch outside the sixth blanking punch forms the paired bends of the plug-in melt; Step 6. The return spring automatically moves the upper die holder upward and resets the fixed plate to automatically return to the position ready for the next forming operation.

[0019] According to a preferred aspect of the invention, step 3 further includes: during the downward movement of the upper die holder, the bending punch abuts against the body portion of the strip and, under the combined action of force and bending groove, deflects toward the pressing punch located therebetween, until the body portion of the strip located between the bending punch and the bending groove is substantially entirely pressed against the side length of the bending groove.

[0020] Other features and advantages of the present invention will partly become apparent to those skilled in the art upon reading this application, and partly will be described in conjunction with the accompanying drawings in the detailed description below. Attached Figure Description

[0021] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings, wherein:

[0022] Figure 1 It is a plan view of a strip with a narrow diameter that can be used in the molding die of the present invention;

[0023] Figure 2 It is by Figure 1 The image shows a plug-in melt made from a narrow strip.

[0024] Figure 3 This is a front view of a molding die according to the invention, wherein the molding die is in the open position to allow insertion of a strip with a narrow diameter;

[0025] Figure 4 yes Figure 3 A three-dimensional view of the molding die;

[0026] Figure 5 yes Figure 3 A three-dimensional view of the molding die, taken from another perspective;

[0027] Figure 6 yes Figure 3 A three-dimensional view of the molding die, taken from yet another perspective;

[0028] Figure 7 yes Figure 3 Top view of the molding die;

[0029] Figure 8 This is a front view of the molding die according to the present invention, wherein some parts have been removed to better show the internal structure and details;

[0030] Figure 9 yes Figure 8 A top view of the molding die;

[0031] Figure 10 yes Figure 8 A three-dimensional view of the molding die;

[0032] Figure 11 This is a perspective view of a molding die according to the present invention, wherein more parts have been removed to better show the internal structure and details;

[0033] Figure 12 yes Figure 11 A top view of the molding die;

[0034] Figure 13 yes Figure 11 The front view of the molding die;

[0035] Figure 14 yes Figure 11 A three-dimensional view of the molding die from another perspective;

[0036] Figure 15 yes Figure 3 The diagram shows the state of the forming die in the open position, with a partial schematic representation of the initial state of the bending punch.

[0037] Figure 16 yes Figure 15 A magnified view of a partial schematic section, showing more details;

[0038] Figure 17 yes Figure 3 The diagram shows the state of the forming die in the bending position, with a partial schematic showing the bending punch in operation.

[0039] Explanation of reference numerals in the attached figures:

[0040] 10. Narrow-diameter strip; 11. Body section; 12. Narrow-diameter section; 20. Insert-type melt;

[0041] 21. Bending section; 100. Forming mold; 101. Spring retainer; 101A. Compression spring;

[0042] 101B. Pressure bar; 102. Upper mold base; 103. Fixing plate; 103A. Guide groove;

[0043] 104A. First clamping punch; 104B. Second clamping punch; 104C. Third clamping punch;

[0044] 104D. Fourth blanking punch; 104E. Fifth blanking punch; 104F. Sixth blanking punch;

[0045] 105A. First turning punch; 105B. Second turning punch; 105C. Third turning punch;

[0046] 105D. Fourth cornering punch; 105E. Fifth cornering punch;

[0047] 106. Die cavity; 106A. Top surface; 106B. Bending groove;

[0048] 107. Lower mold base; 108. Outer guide pillar; 108A. Outer sleeve;

[0049] 109. Support; 110. Bending punch; 200. Forming die;

[0050] X. Length direction; Y. Width direction; Z. Height direction;

[0051] D. Depth of the bending groove; L. Side length of the bending groove; d. Spacing. Detailed Implementation

[0052] The schematic embodiments of the molding die disclosed in this invention will now be described in detail with reference to the accompanying drawings. Although the drawings are provided to illustrate some embodiments of the invention, they are not necessarily drawn to the dimensions of the specific embodiments, and certain features may be enlarged, removed, or partially sectioned to better illustrate and explain the disclosure of the invention. Some components in the drawings may be repositioned according to actual needs without affecting the technical effect. The phrase "in the drawings" or similar expressions appearing in the specification do not necessarily refer to all drawings or examples.

[0053] Certain directional terms used in the description of the accompanying drawings below, such as “inner,” “outer,” “above,” “below,” and other directional terms, will be understood to have their normal meaning and refer to those directions as normally viewed in the accompanying drawings. Unless otherwise specified, the directional terms used in this specification are generally in accordance with the conventional directions understood by those skilled in the art.

[0054] The terms “first,” “first,” “second,” “second,” and similar terms used in this invention do not indicate any order, quantity, or importance, but are used to distinguish one component from others.

[0055] exist Figure 1 The diagram shows a narrow strip 10 that can be used in the molding die 100 of the present invention, wherein the strip 10 is generally designed as a plate made of a material such as copper or a copper-silver alloy with good ductility and conductivity, wherein the thickness of the plate ranges, for example, from 0.1 mm to 2 mm.

[0056] The known material strip used to manufacture fuse elements is generally designed as a long, solid structure. This strip is typically first shaped and bent in a forming die, and then a narrow-diameter punch is used to punch a predetermined diameter onto the bent strip. This avoids the bending process negatively impacting the size of the punched diameter, which in turn affects the current-carrying capacity or breaking current of the resulting fuse element. While this manufacturing process and forming die are feasible in production, they also lead to drawbacks such as complex die design, limited melt fabrication, cumbersome manufacturing process, and relatively high costs.

[0057] Unlike known elongated solid strips, the strip 10 with narrow diameters used in the molding die 100 of the present invention includes multiple sets of narrow diameter portions 12 spaced apart from each other between its opposite ends, wherein these narrow diameter portions 12 are pre-fabricated before the strip 10 is placed into the molding die 100 for subsequent molding processing. Figure 1 As shown, as an example, in Figure 1 The narrow strip 10 shown in the figure comes from... Figure 1Ten sets of narrow sections 12 (highlighted by dashed lines) are arranged at equal intervals from the leftmost to the rightmost end, with adjacent narrow sections 12 connected by the body section 11 that has not been punched. This design allows for a larger narrow diameter of the melt 20 formed from the narrow strip 10, meaning the ratio of narrow diameter to hole size can be smaller. This effectively increases the current-carrying capacity of the melt 20. Furthermore, the reduction in contact resistance allows for a certain increase in the design current density of the melt 20, thus meeting the low-current protection requirements of automotive fuses, especially in the 1.5kA to 3kA fault current range. This design also better meets the performance matching requirements of automotive fuses and relays.

[0058] It should be pointed out that, although in Figure 1 The diagram shows a narrow section 12 with 10 sets of circular through holes. However, those skilled in the art will know that the narrow section 12 can be designed into various narrow structures as needed, such as having several diamond-shaped holes, other irregularly shaped holes, or combinations of various holes spaced apart. At the same time, the size or distance between the body sections 11 of adjacent narrow sections 12 can also be flexibly set.

[0059] exist Figure 2 The diagram shows a plug-in melt 20 prepared according to the present invention. Wherein, as... Figure 2 Clearly shown, compared to the narrow-diameter strip 10 before forming, the corresponding portions of the body portion 11 in the insert-type melt 20 have been bent into multiple (in this case, nine) V-shaped bends, wherein these V-shaped bends are symmetrically distributed about the central V-shaped bend, and preferably, the angles of each of the multiple (in this case, nine) V-shaped bends are formed at approximately 85-100 degrees. The 10 sets of narrow-diameter portions 12 in the insert-type melt 20 remain substantially unchanged or unaffected during the bending or forming process. Simultaneously, the insert-type melt 20 also includes bends 21 connected to its two ends, which are bent outwards to a certain height perpendicular to the length direction.

[0060] In use, the aforementioned plug-in fusible element 20 can be housed in a fusible tube (not shown), for example, containing an insulating material such as quartz sand. The bent portions 21 at both ends extend from both ends of the fusible tube and form pins for subsequent welding or insertion with electrical components by means of the bent portions 21 bending outwards at a certain height perpendicular to the length direction. Here, the fusible tube can be made of high-strength ceramic. In other embodiments, the fusible tube can also be made of glass, reinforced resin, or other insulating materials. Thus, unlike the bolted connections used in the prior art, the fuse with the plug-in fusible element 20 according to the present invention can be detachably installed by plugging in the bent portions 21 at both ends, simplifying operation and facilitating installation. Furthermore, since the extending direction of the bent portions 21 at both ends intersects with the length direction of the fusible tube or fusible element 20, this saves space in the length direction of the fusible tube extension.

[0061] It should be noted that the fuse with the above-mentioned plug-in fuse element 20 according to the present invention can be used not only in the field of new energy vehicles, but also in traditional power generation, power transmission and distribution, metallurgy, mining, electrochemical industry, communications, new energy wind and solar power generation and energy storage, rail transit, ships and other fields.

[0062] exist Figures 3 to 14 The molding die 100 according to the present invention is shown as an example.

[0063] like Figures 3 to 14 As shown, the molding die 100 includes, from bottom to top: a lower die base 107, generally designed as a long plate with partially chamfered corners, preferably made of stainless steel, wherein the lower die base 107 serves as a base for accommodating the die cavity 106 and supports 109 symmetrically arranged on both sides of the die cavity 106 along the X direction. Figure 3 and Figure 5 As clearly shown, the die 106 includes a top surface 106A located at the uppermost point in the vertical direction and a plurality of bending grooves 106B arranged alternately with these top surfaces 106A. The top surfaces 106A are used in the pressing operation detailed below to press and protect the narrow diameter portion 12 of the strip 10, and the bending grooves 106B are used in the bending operation detailed below to shape or bend the body portion 11 of the strip 10 into the shape described below. Figure 2 The V-shaped bend shown has an included angle of approximately 85-100 degrees. Meanwhile, the supports 109 located on both sides of the die 106 are used to lay the strip 10 of a predetermined length flat on the die 106 in a preset position and to ensure that it does not shift along the length direction (i.e., the X direction) during the molding operation.

[0064] Furthermore, four parallel outer guide posts 108 extending vertically along the height direction (Z direction) are respectively provided at the four corners of the lower mold base 107. An outer sleeve 108A is fitted onto the upper end of the outer guide posts 108 along the height direction, and an upper mold base 102 located vertically above the lower mold base 107 is fixedly connected to the top of the outer sleeve 108A. The upper mold base 102 is substantially the same size and shape as the lower mold base 107, and a pneumatic or electric actuation cylinder (not shown) is provided on the side of the upper mold base 102 facing away from the lower mold base 107 for pressing it towards the lower mold base 107 along the height direction (Z direction). When the actuation cylinder is activated, the upper mold base 102 is guided by the cooperation of the four outer guide posts 108 and the matching outer sleeve 108A along the height direction (Z direction)... Figure 3 The upper mold base 102 is pressed down towards the lower mold base 107 in the Z direction. Thus, during the pressing down of the upper mold base 102, by means of the outer guide post 108 and the outer sleeve 108A which is shaped to match it and also extends along the height direction (Z direction), only the outer guide post 108 and the upper mold base 102 which is fixedly connected to the outer sleeve 108A are allowed to descend or subsequently reset along the height direction (Z direction).

[0065] To achieve the reset of the upper mold base 102, a return spring (not shown) is provided in the vertically extending outer sleeve 108A for storing bias energy during pressing. This return spring can, for example, be sleeved on the outside of the vertically extending outer guide post 108 and sandwiched between the outer sleeve 108A and the lower mold base 107. Thus, after the pressing operation is completed, the upper mold base 102 can be automatically reset to its initial position by means of the elastic potential energy stored in the return spring. That is, the upper mold base 102 can be reset via... Figure 3 The four outer guide posts 108 shown can be guided vertically downward and upward relative to the lower mold base 107 by being biased by a reset spring.

[0066] like Figure 3-5 As shown, the molding die 100 of the present invention also includes a molding die head 200 disposed directly above the die cavity 106. This molding die head 200 includes a fixing plate 103 fixedly connected to the upper die base 102 directly above the die cavity 106, and a plurality of blanking punches disposed therein, which are movable relative to the fixing plate 103 in the height direction; a plurality of bending punches arranged interleaved with these blanking punches; and a bending punch 110 located on the outermost side. Specifically, in Figure 3 The forming die 200 shown has a number of blanking punches that match the number of the top surface 106A of the die cavity 106 (which also matches the number of groups of the narrow diameter portion 12, here being 10) (where reference numerals 104A to 104F only partially indicate these blanking punches). It should be noted that since both the blanking punches and the bending punches are arranged symmetrically about the length direction X, therefore... Figure 3Only the multiple blanking punches and bending punches located on the left side are shown in the image; those skilled in the art will understand that... Figure 3 Correspondingly on the right side, there are also multiple blanking punches and bending punches arranged in an alternating pattern, and their arrangement is similar to... Figure 3 The arrangement shown on the left is consistent or symmetrical.

[0067] Among them, Figure 3 Along the length direction, a first blanking punch 104A, closest to the top surface 106A in the height direction (Z direction), is arranged at the center of the forming die head 200. Pairs of first bending punches 105A, subsequently used to form V-shaped bends, are arranged on both sides of the first blanking punch 104A in the length direction (X direction). The height of these pairs of first bending punches 105A in the height direction (Z direction) is slightly less than that of the first blanking punch 104A and is at least partially aligned with the bending groove 106B located below it. Figure 3 Along the length direction X, a second pressing punch 104B is arranged adjacent to the first bending punch 105A. The second pressing punch 104B is slightly smaller in height than the first bending punch 105A and is designed to cooperate with the top surface 106A to press against the corresponding narrow section 12 of the strip 10 with a narrow diameter. On both sides of the second pressing punch 104B, there are pairs of second bending punches 105B arranged for forming V-shaped bends. The height of these pairs of second bending punches 105B is slightly smaller than that of the second pressing punch 104B in the height direction and is at least partially aligned with the bending groove 106B located below it.

[0068] like Figure 3 As shown, following the same arrangement, along Figure 3The third pressing punch 104C, the fourth pressing punch 104D, the fifth pressing punch 104E and the sixth pressing punch 104F are arranged outward along the length direction. The distance of these pressing punches from the top surface 106A along the height direction Z gradually increases. Furthermore, as pairs of bending punches associated with the second pressing punch 104B, the third pressing punch 104C, the fourth pressing punch 104D, the fifth pressing punch 104E, and the sixth pressing punch 104F, multiple pairs of third bending punches 105C, fourth bending punches 105D, and fifth bending punches 105E are alternately arranged between the third pressing punch 104C, the fourth pressing punch 104D, the fifth pressing punch 104E, and the sixth pressing punch 104F. The height of each of these pairs of third bending punches 105C, fourth bending punches 105D, and fifth bending punches 105E in the height direction is less than that of the third pressing punch 104C, the fourth pressing punch 104D, the fifth pressing punch 104E, and the sixth pressing punch 104F. Finally, two bending punches 110 are symmetrically arranged on the outermost side of the forming die head 200 along the length direction (X direction) for bending the strip 10 with a narrow diameter.

[0069] exist Figures 7 to 10 The diagram shows the arrangement of the blanking punches in the forming die 200, a plurality of bending punches arranged interlaced with these blanking punches, and the outermost bending punch 110 in the fixed plate 103. The fixed plate 103 has a plurality of guide grooves 103A extending along the height direction corresponding to the positions of these punches, thereby allowing the punches to be displaceably accommodated within the fixed plate 103 relative to the height direction. In particular, as shown in... Figure 8 and 10 As clearly shown, for each punch located in the guide groove 103A of the fixed plate 103, each punch is equipped with a corresponding pressure bar 101B, which will be put into operation sequentially in the bending operation below, thereby allowing the material strip 10 with narrow diameter to be pressed, bent and folded in sequence, while ensuring that the narrow diameter portion 12 of the material strip 10 with narrow diameter is not adversely affected during the forming operation.

[0070] like Figures 3 to 6 As shown, in order to accommodate the pressure bar 101B located on the back side of these punches, a spring retainer 101 is also provided on the side of the upper die holder 102 facing away from the fixed plate 103, wherein preferably as follows: Figure 7As shown, the spring fixing seat 101 is provided with a plurality of spring fixing holes corresponding to the positions of the pressure rod 101B on the back side of the punch. These spring fixing holes can be designed as blind holes with one side open, wherein one end of the pressure rod 101B is located at the closed end of the blind hole, and the other end is connected to the punch to which it is attached by means of the open side or end of the blind hole.

[0071] exist Figure 15 and 16 As shown, a compression spring 101A is provided in the spring fixing hole corresponding to the position of the pressure rod 101B in the spring fixing seat 101. That is, each pressure punch and the bending punch arranged therewith are respectively equipped with a pressure rod 101B and a compression spring 101A connected thereto. This allows the pressure punch or bending punch that has already abutted against the top surface 106A or bending groove 106B in the die 106 during the pressing down of the forming die head 200 to not affect the continued pressing down of the pressure punch or bending punch that has not yet abutted. This allows the pressure punch and the bending punch arranged therewith to work in sequence to complete the pressing and bending, and ensures that the narrow diameter portion 12 of the narrow diameter strip 10 will not be adversely affected during the forming operation.

[0072] Especially Figure 15 and 16 As shown in the diagram, taking the centrally located first pressing punch 104A and the first bending punches 105A located on either side of it as examples, the generally V-shaped or triangular bending groove 106B located below it has a... Figure 15 The depth is indicated by D, and the side length is indicated by L. Correspondingly, such as... Figure 16 As shown, when the forming die head 200 is in Figure 15 In the initial or non-pressed position shown, unlike the molds in the prior art, the first bending punches 105A located on both sides of the first pressing punch 104A are arranged at an angle relative to the first pressing punch 104A, such that the bending tip of the first bending punch 105A has a distance d relative to the lowest point of the first pressing punch 104A in, for example, the height direction Z direction. This distance d is designed to be, for example, 0.9 to 1.1 times the side length L of the bending groove 106B. As a result, the longitudinal axis of the first bending punches 105A located on both sides of the first pressing punch 104A has an angle of, for example, about 3-5 degrees, preferably 4 degrees, relative to the longitudinal axis of the first pressing punch 104A.

[0073] The inventors of this invention discovered that when bending a narrow-diameter strip 10, if multiple bending punches without height differences are simultaneously engaged with the bending groove 106B for bending, insufficient lateral stretching deformation of the strip 10 occurs due to multiple body sections 11 simultaneously, thereby increasing the probability of defective products. Simultaneously, when the bending punches bend the body section 11, the bending force inevitably travels from the body section 11 to the narrow-diameter section 12 of the strip 10, thus substantially affecting the pre-formed narrow-diameter section 12.

[0074] Without adhering to theoretical limitations, the inventors believe that a pre-pressing operation can be performed on the narrow diameter portion 12 near the main body 11 before bending it. This is achieved by using a pressing punch and the top surface 106A to immovably protect the narrow diameter portion 12 along its length, effectively blocking the force transmission from the bent main body 11 to the pressed narrow diameter portion 12, thus ensuring that the narrow diameter portion 12 near the main body 11 is protected from the bending operation. Furthermore, by first pressing and protecting the narrow diameter portion 10 at its center position using a first pressing punch 104A, and then sequentially bending multiple main body portions 11 of the narrow diameter portion 10 from the inside out, the inventors avoid simultaneously applying lateral stretching deformation operations to multiple main body portions 11 of the narrow diameter portion 10, which would increase the scrap rate. This effectively ensures a high yield of the finished product without affecting production efficiency.

[0075] Furthermore, the inventors discovered that by means of the first pressing punch 104A and the first bending punch 105A located on either side of it being arranged at an angle relative to each other, compared to the prior art where the two are usually designed with no included angle or parallel longitudinal axes, this design allows the first bending punch 105A to contact first. Figure 1 As the forming die head 200 continues to descend, the body portion 11 of the strip 10, located between the first bending punch 105A and the bending groove 106B, will approach the first pressing punch 104A from the first bending punch 105A and thus adhere from top to bottom to the side length of the bending groove 106B. Here, since the distance d between the bending tip of the first bending punch 105A and the first pressing punch 104A is designed to be, for example, 0.9 to 1.1 times the side length L of the bending groove 106B, this ensures that the tip of the first bending punch 105A... Figure 17 When the material strip 10 reaches the lowest point of the bending groove 106B as shown, the body portion 11 of the strip 10 located between the first bending punch 105A and the bending groove 106B is almost entirely pressed against the side length L of the bending groove 106B, thereby forming Figure 2 The V-shaped bend is shown in the image.

[0076] It is believed that, compared with the prior art, the V-shaped bend formed in this way significantly reduces the tension or stress on the strip 10, thereby reducing the impact of the bending operation on the narrow section 12 near the body section 11 to a smaller extent.

[0077] Next, combine Figures 8 to 13 To describe the use of the molding die 100 of the present invention Figure 1 The narrow strip 10 is used for forming operations to produce... Figure 2 The manufacturing method of the plug-in melt 20 shown in the figure:

[0078] When it is necessary to produce a plug-in fuse 20 of a certain predetermined length, taking a low-voltage fuse as an example, for instance, it is necessary to manufacture a strip 10 with a narrow diameter approximately 100 mm in length, wherein, for example... Figure 1 As shown, the narrow strip 10 has 10 sets of narrow sections 12 and multiple body sections 11 arranged alternately therewith, which will be bent by a bending punch.

[0079] First, in step 1, the position of the supports 109 located on both sides of the die 106 in the X direction of the extension direction is adjusted according to the selected length of the narrow strip 10. This is to ensure that the positions of the 10 sets of narrow sections 12 of the narrow strip 10 placed on the two supports 109 correspond one-to-one with the positions of the top surface 106A on the die 106, and that the positions of the multiple body sections 11 correspond one-to-one with the positions of the bending grooves 106B in the die 106.

[0080] Then proceed to step 2, and then activate the actuation cylinder located on the back side of the upper mold base 102 of the forming mold 100 to drive the upper mold base 102 and the forming mold head 200 with the fixing plate 103 fixedly connected thereto to descend in a controlled manner under the guidance of the outer guide post 108, which in turn causes the multiple pressing punches connected to the forming mold head 200 to descend as well.

[0081] Since the first blanking punch 104A, located at the center of the forming die head 200, is at the bottom in the height direction Z (here, as an example, the first blanking punch 104A extends about 0.1-1.5 mm beyond the first bending punch 105A in the height direction), during the pressing down of the upper die holder 102 and the forming die head 200, the first blanking punch 104A, located at the center of the forming die head 200, first contacts the corresponding narrow portion 12 of the narrow strip 10 and presses it against the top surface 106A of the die cavity 106.

[0082] Next, proceeding to step 3, as the upper die holder 102 and the forming die head 200 continue to descend, the first bending punches 105A located on both sides of the first pressing punch 104A in the forming die head 200 along the length direction come into contact with the body portion 11 of the narrow strip 10 located at the corresponding bending groove 106B in the die cavity 106 to perform a bending operation to form Figure 2 The V-shaped bend of the plug-in melt 20 is shown in the image. (Example) Figure 16 and 17 As shown, before the first bending punches 105A on both sides contact the body portion 11 of the strip 10, the first bending punches 105A have a certain distance d relative to the first pressing punches 104A, wherein the distance d is designed to be, for example, 0.9 to 1.1 times the side length L of the bending groove 106B. As the forming die head 200 continues to descend, the first bending punches 105A will abut against the body portion 11 of the strip 10 and thus, under the combined action of force and the bending groove 106B, move along... Figure 16 The arrow shown deflects towards the first pressing punch 104A located therebetween. As a result, the body portion 11 of the strip 10 located between the first bending punch 105A and the bending groove 106B will, with this deflection, adhere from top to bottom to the side length L of the bending groove 106B, and thus the tip of the first bending punch 105A, as... Figure 17 When the material strip 10 reaches the lowest point of the bending groove 106B as shown, the body portion 11 of the strip 10 located between the first bending punch 105A and the bending groove 106B is almost entirely pressed against the side length L of the bending groove 106B, thereby forming Figure 2 The V-shaped bend is shown in the figure. During this period, since the corresponding narrow section 12 of the narrow strip 10 located between the two first bending punches 105A has been pressed between the first pressing punch 104A and the top surface 106A, the narrow section 12 located between the two body sections 11 is basically unaffected by the lateral tension.

[0083] Next, proceeding to step 4, the pressure bar 101B and compression spring 101A located behind the first bending punch 105A are compressed and retracted, so that the first bending punch 105A, which is already abutting against the bending groove 106B, does not obstruct the downward movement of the adjacent second pressing punch 104B. As a result, the narrow section 12 on one side of the already bent V-shape is then pressed between the second pressing punch 104B and its corresponding top surface 106A, and is ready for the subsequent bending operation of the body section 11 located on its outer side. Next, by means of the second bending punch 105B located outside the second pressing punch 104B, the body section 11 of the narrow strip 10 on the bending groove 106B is bent to form more V-shapes in the plug-in melt 20. During the bending operation, since the corresponding narrow section 12 of the narrow strip 10 located between the first bending punch 105A and the second bending punch 105B has been pressed between the second pressing punch 104B and the top surface 106A, the narrow section 12 located between the two body sections 11 is basically unaffected by the lateral tension.

[0084] Then, step 4 is repeated, and the third pressing punch 104C, the third bending punch 105C, the fourth pressing punch 104D, the fourth bending punch 105D, the fifth pressing punch 104E, and the fifth bending punch 105E are used alternately to bend the body portion 11 of the narrow strip 10, thereby forming more V-shaped bends. During this period, thanks to the arrangement of the pressure bar 101B, the operation of these pressing punches and bending punches does not affect or interfere with each other, and reliably ensures that the narrow portion 12 near the body portion 11 is protected from lateral tension before bending the body portion 11.

[0085] Then, proceeding to step 5, the narrow strip 10 is pressed against the die 106 by the sixth blanking punch 104F, and immediately thereafter, the bending punch 110 outside the sixth blanking punch 104F forms the paired bent portions 21 of the plug-in melt 20. At this point, the forming die 200 will come into contact with the limiting member (not shown), thus reaching the lower stop of its downward stroke and being unable to continue moving downward. Thus, Figure 2 All molding operations of the plug-in melt 20 shown in the figure have been completed.

[0086] After the plug-in melt 20 is formed, the spring sleeved on the outside of the outer guide post 108 automatically moves the upper mold base 102 and the forming die head 200 with the fixing plate 103 upwards to the initial position. At this time, the operator can take out the formed plug-in melt 20. Alternatively, the formed plug-in melt 20 can be blown out or picked up by air blowing or a robotic arm, and then the next strip 10 with a narrow diameter to be formed can be placed in. In short, after the pressing and forming is completed, the forming die 100 automatically returns to a state where it can perform the next forming operation without any intervention from the operator.

[0087] It should be understood that although this specification describes various embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0088] The above description is merely an illustrative embodiment of the present invention and is not intended to limit the scope of the invention. Any equivalent changes, modifications, and combinations made by those skilled in the art without departing from the concept and principles of the present invention should fall within the scope of protection of the present invention.

Claims

1. A molding die for forming a strip with narrow diameters into an insert-type melt, wherein the strip with narrow diameters comprises a plurality of narrow diameter portions spaced apart from each other between its opposite ends and a body portion located at adjacent narrow diameter portions, characterized in that... ,include: A lower mold base, wherein a die cavity is placed on the lower mold base, wherein the die cavity includes a top surface arranged at the uppermost position in the vertical direction and a plurality of bending grooves arranged alternately with these top surfaces; An upper mold base is disposed vertically above the lower mold base, wherein the upper mold base is configured to be guided vertically downward and upward relative to the lower mold base via multiple outer guide posts biased by return springs; The forming die head located above the cavity die includes: A fixing plate that is fixedly connected to the upper mold base; A plurality of pressing punches are disposed therein, which can be displaced relative to a fixed plate in the height direction, wherein the pressing punches are designed to be at least partially aligned with a top surface in the height direction, and wherein the plurality of pressing punches includes a centrally arranged first pressing punch that is closest to the top surface in the height direction. A plurality of bending punches are arranged interleaved with these blanking punches, wherein the bending punches are designed to be at least partially aligned with the bending grooves along the height direction, and wherein the plurality of bending punches include pairs of bending punches located on both sides of the first blanking punch along the length direction; and The outermost bending punch; The forming mold is designed to perform pressing, bending of the body and bending of both ends of the strip along the length direction from the central pressing punch to both sides during the lowering of the upper mold base relative to the lower mold base. The pair of bending punches are arranged at an angle relative to the pressing punch located between them, such that the pointed part of the bending punch is spaced apart from the bottom of the pressing punch. The longitudinal axis of the bending punch is designed to have an angle of 3 to 5 degrees relative to the longitudinal axis of the pressing punch located therebetween.

2. The molding die as described in claim 1, characterized in that: The number of the blanking punches is the same as the number of the top surfaces in the die, and the number of the bending punches is the same as the number of the bending grooves.

3. The molding die as described in claim 2, characterized in that: It also includes second, third, fourth, fifth and sixth pressing punches arranged at intervals along the length direction, wherein the distance of these pressing punches from the top surface gradually increases.

4. The molding die as described in claim 3, characterized in that: It also includes pairs of bending punches that are respectively assigned to the second, third, fourth, fifth and sixth pressing punches along the length direction, wherein the height of these pairs of bending punches along the height direction is less than that of the second, third, fourth, fifth and sixth pressing punches to which they are assigned.

5. The molding die as described in claim 1, characterized in that... It also includes a spring fixing seat arranged on the side of the upper mold base facing away from the fixed plate, wherein the spring fixing seat is provided with a plurality of spring fixing holes, wherein the spring fixing holes are provided with a group of compression springs and pressure rods, wherein the group of compression springs and pressure rods are associated with the pressing punch, bending punch and folding punch.

6. The molding die as described in claim 5, characterized in that... The bending groove is designed to have depth and side length, and the distance between the bending punch and the pressing punch is designed to be 0.9 to 1.1 times the side length of the bending groove to which it is attached.

7. A method for forming a strip with a narrow diameter into an interlocking melt using a forming die, wherein the forming die is a forming die as described in any one of claims 1 to 6, characterized in that... Includes the following steps: Step 1. Adjust the position of the die along the length direction according to the selected length of the narrow strip, so that the position of the narrow part in the narrow strip corresponds one-to-one with the position of the top surface of the die, and the position of multiple body parts corresponds one-to-one with the position of the bending groove of the die. Step 2. Move the upper die holder and forming die head downwards, so that the centrally located blanking punch contacts the narrow section first and presses it against the top surface of the die cavity; Step 3. The bending punches on both sides of the centrally located blanking punch bend the body part located in the bending groove of the die to form a V-shaped bend of the plug-in melt. Step 4. The second, third, fourth, fifth and sixth blanking punches are used in succession to contact the corresponding narrow section and press it against the top surface of the die. At the same time, the pairs of bending punches associated with the second, third, fourth, fifth and sixth blanking punches are used to bend the body section located at the bending groove of the die to form multiple V-shaped bends of the plug-in melt. Step 5. Using the bending punch on the outside of the sixth pressing punch, form the paired bent portions of the plug-in melt; Step 6. The return spring automatically moves the upper mold base upward and resets the fixing plate, so as to automatically return to the position ready for the next molding operation; Step 3 further includes: during the downward movement of the upper die holder, the bending punch abuts against the body of the strip and, under the combined action of force and bending groove, deflects toward the pressing punch located therein, until the body of the strip located between the bending punch and the bending groove is basically completely pressed against the side length of the bending groove.

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