A burr-free punching device for chain links with double rounded corners.

Abstract

A burr-free punching device for chain links with double rounded corners, relating to the field of progressive die technology, includes a progressive die body comprising an upper die and a lower die. A strip of material passes between the upper and lower dies. Along the material strip's path, from left to right, are arranged a: a coarse punching station, a first guiding station, a pre-punching station, a fine punching station, a second guiding station, and a blanking station. The pre-punching station is used to punch out a first rounded corner strip at the upper edge of the pre-punched part. The blanking station punches out a second rounded corner strip at the lower edge of the blanked part simultaneously with blanking. This invention provides a burr-free punching device for chain links with double rounded corners, aiming to overcome the technical bias of existing progressive die chain plate punching by designing the chain link contour for two punching operations. The first pre-punching operation pre-punches the material to a certain depth, causing plastic deformation and creating a first rounded corner strip at the cutting edge. The second punching operation, in the opposite direction, completes the second rounded corner strip and blanks the material.

Description

Technical Field

[0001] This invention relates to the field of progressive die technology, specifically to a burr-free punching device for chain segments with double rounded corners. Background Technology

[0002] In the manufacturing process of roller chains, the inner and outer chain links are mostly processed using a punching process. As the carrier parts of the chain, the punching quality of the chain links directly affects the appearance quality of the chain, specifically in the following ways:

[0003] 1. After the roller chain links are stamped, four types of fractures appear sequentially on the cross-section of the chain link profile: rounded corners, bright bands, fracture bands, and burr areas. However, existing progressive die chain link stamping is mostly a one-time blanking process, and the appearance of the part cross-section is improved by adjusting the blanking gap, which cannot fundamentally solve the problems of cross-section defects and burr generation.

[0004] 2. If the surface at the break zone of the punching is uneven or there is secondary tearing, or if there are large burrs on the edge of the part, then appropriate surface treatment is required, which will increase the manufacturing cost of the product.

[0005] 3. Material properties have a significant impact on the cross-section of the parts. Under these circumstances, existing punching technology cannot guarantee the consistency of the chain link cross-section, which affects the chain assembly accuracy. Summary of the Invention

[0006] This invention provides a burr-free punching device for chain links with double rounded corners, aiming to overcome the technical bias of existing progressive die chain plate punching by designing the chain link contour for two punching operations. The first punching operation pre-punches the material to a certain depth, causing plastic deformation and creating a first rounded corner band at the cutting edge. The second punching operation completes the second rounded corner band and removes the material.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] A burr-free punching device for chain links with double rounded corners includes a progressive die body, which comprises an upper die and a lower die. The strip passes between the upper die and the lower die. Along the channel of the strip, from left to right, there are: a coarse punching station, a first guiding station, a pre-punching station, a fine punching station, a second guiding station, and a blanking station. The pre-punching station is used to punch out the first rounded corner strip at the upper edge of the pre-punched part. The blanking station punches out the second rounded corner strip at the lower edge of the blanked part while blanking.

[0009] Preferably, the upper mold includes an upper mold base and a fixing plate connected to the lower end of the upper mold base. From left to right, the lower end of the fixing plate has an upper stripper plate 1, an upper concave mold plate, and an upper stripper plate 2 arranged side-by-side. The lower mold includes a lower mold base, a lower concave mold pad connected to the upper end of the lower mold base, and lower concave mold plates 1, a lower stripper plate, and a lower concave mold plate 2 arranged side-by-side on the upper end of the lower concave mold pad. The lower concave mold plate 1 and the upper stripper plate 1 are vertically opposite each other, and a rough punching station and a guiding station 1 are formed sequentially between the upper stripper plate 1 and the lower concave mold plate 1. The upper concave mold plate and the lower stripper plate are vertically opposite each other, and a pre-punching station is formed between the upper concave mold plate and the lower stripper plate. The upper stripper plate 2 and the lower concave mold plate 2 are vertically opposite each other, and a fine punching station, a guiding station 2, and a blanking station are formed between the upper stripper plate 2 and the lower concave mold plate 2.

[0010] The fixed plate, the upper concave template, and the lower end face of the upper mold base are fixedly connected by bolts. The upper unloading plate one and the upper unloading plate two are respectively connected to the lower mold base 6 through the unloading plate guide post 14 that passes through the lower concave template one 4 or the lower concave template 26 and the lower concave mold pad. The lower unloading plate and the lower concave mold pad are connected by the unloading plate guide post. The lower concave template one, the lower concave template two, and the lower concave mold pad are fixedly connected to the lower mold base by bolts.

[0011] Preferably, a vibration damping and buffering mechanism is further provided between the upper mold and the lower mold. The vibration damping and buffering mechanism includes a support rod, a first mounting groove, a second mounting groove, a first limiting block, a second limiting block, a first spring, and a second spring. The support rod extends longitudinally through either the first or second upper unloading plate. A first limiting block and a second limiting block are provided at the top and bottom of the support rod. The bottom end of the first limiting block is in contact with the upper surface of either the first or second upper unloading plate, and the top end of the second limiting block is in contact with the lower surface of either the first or second upper unloading plate. The first mounting groove extends through the fixing plate and the upper mold base. A first spring is installed in the lower part of the first mounting groove, and the top end of the first limiting block is in contact with the lower surface of either the first or second upper unloading plate. The lower end of the first spring is connected and can partially enter the first mounting groove when the first spring is compressed. The first or second concave template is provided with a second mounting groove at a position perpendicular to the first mounting groove. The second mounting groove passes through the first or second concave template and the concave mold pad. The upper part of the second mounting groove is installed with a second spring. The bottom end of the second limiting block is connected to the top end of the second spring and can partially enter the second mounting groove when the second spring is compressed. The lower part of the support rod is inserted into the second spring. When the first spring and the second spring are in their natural state, the first concave template and the first upper unloading plate are separated from each other; the second concave template and the second upper unloading plate are separated from each other.

[0012] Preferably, the coarse punching station includes a coarse punch pin, the bottom of which is fixedly connected to a fixed plate, and the top of which slides longitudinally through the lower surface of the upper unloading plate; the guiding station includes a guide pin, the bottom of which is fixedly connected to a fixed plate, and the top of which slides longitudinally through the lower surface of the upper unloading plate.

[0013] Preferably, the pre-punching station includes an upper die and a pre-punching punch located on the upper die plate. An ejector is provided inside the upper die, with a slidable through-plate at the top of the ejector connected to a nitrogen spring embedded in the upper die base. The nitrogen spring has a flange at its top, which is bolted to the upper die base. The nitrogen spring is connected to a balancing nitrogen spring via a high-pressure pipeline, forming a management system with the same pressure. The high-pressure pipeline is also connected to a shock-resistant pressure gauge. The balancing nitrogen spring is arranged inside the upper die base, and a set bolt is provided on the outside of the balancing nitrogen spring compression rod. Adjusting the set bolt increases or decreases the system pressure, thus changing the... The nitrogen spring outputs pressure at the top of the ejector; the lower end of the ejector is used to apply pressure and level the pre-punched part; the upper surface of the lower die base is also provided with a first mounting hole, and a rectangular helical spring is provided in the first mounting hole. The top end of the rectangular helical spring is connected to a guide post. The guide post can slide through the lower die pad and is fixedly connected to the lower stripper plate. In the open state, the lower surface of the lower stripper plate is separated from the upper surface of the lower die pad. The lower end of the pre-punch punch is fixedly connected to the upper surface of the lower die pad, and the upper end can slide longitudinally through the upper surface of the lower stripper plate. The cutting edge of the upper die is used to form the first rounded corner strip.

[0014] Preferably, the fine punching station includes a fine punching pin, the bottom of which is fixedly connected to a fixed plate, and the top of which slides longitudinally through the lower surface of the upper unloading plate 2; the guiding station 2 includes a guide pin, the bottom of which is fixedly connected to a fixed plate, and the top of which slides longitudinally through the lower surface of the upper unloading plate 2.

[0015] Preferably, the blanking station includes a blanking punch, the upper end of which is fixedly connected to the lower surface of the fixed plate, and the lower end of which slidably passes through the lower surface of the upper unloading plate II along the longitudinal direction; the lower surface of the upper die base is also provided with a mounting hole II, and a rectangular helical spring II is provided in the mounting hole II. The bottom end of the rectangular helical spring II is connected to a pressure rod, which slidably passes through the fixed plate and is fixedly connected to the upper unloading plate II. In the open die state, the upper surface of the upper unloading plate II is disengaged from the lower surface of the fixed plate; a blanking hole is provided in the lower die below the blanking punch, and the shape and size of the blanking hole match the shape and size of the formed chain piece, and the upper surface of the blanking hole... The end opening is located on the upper surface of the lower concave template two, and the lower end passes through the lower concave die pad and the lower die base, forming a blanking part outlet on the lower surface of the lower die base; the top of the blanking hole is provided with a blanking punch die for use with the blanking punch, the blanking punch has a receiving cavity inside, and the receiving cavity is connected to a cooling and lubricating medium supply device under pressure conditions, and several spray holes are evenly distributed around the axis in the middle of the side wall of the blanking punch. During the blanking process, the supply device pumps the cooling and lubricating medium directly into the cutting edge of the blanking punch die through the spray holes for lubrication and cooling, and at the same time flushes away the blanking material adhering to the blanking punch, the cutting edge of the blanking punch die is used to form the second rounded corner strip.

[0016] The present invention provides a chain link cross-section double-rounded corner burr-free punching device with the following beneficial effects:

[0017] This invention effectively solves the problem of burrs and protrusions on the cross-section of chain link parts during stamping. The chain link holes are designed with both coarse and fine punching to ensure a stable bright band and smooth hole edges. A pre-punching punch is installed inside the die body, which squeezes the material strip and creates a first rounded corner at the cutting edge of the upper die plate. An ejector leveling device is installed above the pre-punching station to ensure the flatness of the chain link parts. At the blanking station, the part is separated from the material by the action of the blanking punch and blanking die, and a second rounded corner is created on the lower edge contour of the blanked part. As described above, this invention solves the problem of inconsistent blanking cross-sections in chain link parts, achieves burr-free blanking, meets the appearance quality requirements of chain link parts, eliminates the surface treatment process, and achieves cost reduction and efficiency improvement in production. Attached Figure Description

[0018] Figure 1 A three-dimensional structural diagram of the present invention;

[0019] Figure 2 A cross-sectional view of the present invention along the AA direction;

[0020] Figure 3 A three-dimensional structural diagram of the present invention;

[0021] Figure 4A partial structural diagram of point B in this invention;

[0022] Figure 5 A partial structural diagram of point C in this invention;

[0023] Figure 6 The chain piece punching layout diagram of the present invention;

[0024] Figure 7 A comparison diagram of the punching effects of existing chain links and the chain links of this invention;

[0025] Figure 8 The diagram below illustrates the working principle of this invention. In the diagram, the upper left part is a schematic diagram of the pre-punching station, the upper right part is a schematic diagram of the blanking station, and the lower part is a schematic diagram of the entire punching process of the strip.

[0026] Figure 9 A schematic diagram of a management system in which the top nitrogen spring is connected to the balancing nitrogen spring through a high-pressure pipeline to form a system with the same pressure.

[0027] 001. Fracture zone; 002. Rounded corner zone; 003. Burr zone; 004. First rounded corner zone; 005. Second rounded corner zone; 006. Displacement direction of pre-punch punch; 007. Displacement direction of blanking punch; 01: Material strip; 02: Rough punching station; 03. Guiding station one; 04: Pre-punch station; 05: Fine punching station; 06: Guiding station two; 07: Blanking station; 1: Upper die base; 2: Fixing plate; 3: Upper stripper plate one; 4: Lower concave die plate one; 5: Lower concave die pad; 6: Lower die base; 7: M30 set bolt; 8: Upper stripper plate two; 9: Lower stripper plate; 10: Upper concave die plate; 11: Anti-vibration pressure gauge; 12: ... 13: Set bolt; 14: Pre-punch punch; 15: Unloading plate guide post; 16: Rough punch pin; 17: Floating pin; 18: Balance nitrogen spring; 19: Ejector nitrogen spring; 20: Ejector; 21: Rectangular helical spring one; 22: Pressure detection sensor; 23: High pressure pipeline; 24: Pre-punch part; 25: Guide post one; 26: Recessed template two; 27: Blanking part; 28: Outer guide post; 29: Second mounting slot; 30: Second spring; 31: Set nut; 32: Support rod; 33: First mounting slot; 34: First spring; 35: Second limit block; 36: First limit block; 37: Blanking punch. Detailed Implementation

[0028] The following description provides a detailed explanation of the embodiments of the present invention in a step-by-step manner. This description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0029] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or a specific orientational structure and operation. Therefore, they should not be construed as limiting this invention.

[0030] For ease of description, this invention uses the direction of the conveyor belt's movement as right and the opposite direction as left.

[0031] Example 1

[0032] A burr-free punching device for chain links with double rounded corners, such as... Figure 1 , 6 As shown, the progressive die body includes an upper die and a lower die. The strip 01 passes between the upper die and the lower die. The channel along the strip is arranged from left to right as follows: a rough punching station 02, a first guiding station 03, a pre-punching station 04, a fine punching station 05, a second guiding station 06, and a blanking station 07. The pre-punching station 04 is used to punch out the first rounded corner strip 004 at the upper edge of the pre-punched part 24. The blanking station 07 is used to punch out the second rounded corner strip 005 at the lower edge of the blanked part 27 while blanking.

[0033] This example provides the most basic structure of the present invention, wherein the coarse punching station and the fine punching station are used to punch holes in the chain plates. Coarse and fine punching improves the brightness of the chain plate holes and suppresses the formation of burrs. The first and second guide stations used in this invention are common methods in the prior art, achieving accurate positioning of the material strip through the cooperation of guide pins and the punched chain plate holes. Contents not described in this invention are solved using existing technical solutions and will not be elaborated upon here.

[0034] The chain link contour punching in this invention is achieved through a pre-punching station and a blanking station, specifically:

[0035] In the pre-punching station, the pre-punching punch 13 applies a punching force from the lower surface of the strip 01, which, combined with the cutting edge contour of the upper die plate 10, causes plastic deformation of the upper surface of the strip 01, generating a first rounded corner strip 004 around the upper edge of the pre-punched part 24. In the blanking station 07, the blanking punch 37 applies a punching force in the opposite direction to the pre-punching station from the upper surface of the strip 01 at the pre-punched part 24, which, combined with the cutting edge contour of the blanking punch die of the lower die plate 26, causes the chain piece to detach from the strip 01. At the same time as the blanking station 07 completes the blanking, the lower surface of the blanked part 27 is also subjected to force to extrude a second rounded corner strip 005.

[0036] This invention improves the contour blanking of the part into a two-step reverse blanking, and uses the two blanking to generate double collapse corners on the top and bottom surfaces of the part, ensuring that the two sides of the part are consistent and suppressing the generation of burrs on the contour of the part. This combination method changes the long-standing technical bias and overcomes the defects of the prior art.

[0037] Example 2

[0038] This implementation is an improvement based on Example 1, specifically as follows:

[0039] like Figure 1-9 As shown, the upper mold includes an upper mold base 1 and a fixing plate 2 connected to the lower end of the upper mold base 1. The lower end of the fixing plate 2 has an upper ejector plate 3, an upper concave mold plate 10, and an upper ejector plate 26 arranged side-by-side in the left-right direction. The lower mold includes a lower mold base 6, a lower concave mold pad 5 connected to the upper end of the lower mold base 6, and lower concave mold plates 4, lower ejector plates 9, and lower concave mold plates 26 arranged side-by-side on the upper end of the lower concave mold pad 5 in the left-right direction. The lower concave mold plates 4 and 8 are... The upper unloading plate 10 and the lower unloading plate 9 are vertically aligned, and a coarse punching station 02 and a guide station 03 are formed sequentially between the upper unloading plate 10 and the lower unloading plate 9; the upper unloading plate 28 and the lower unloading plate 26 are vertically aligned, and a fine punching station 05, a guide station 26, and a blanking station 07 are formed between the upper unloading plate 28 and the lower unloading plate 26;

[0040] The fixed plate 2, the upper concave template 10 and the lower end face of the upper mold base 1 are fixedly connected by bolts. The upper unloading plate 3 and the upper unloading plate 8 are respectively connected to the lower mold base 6 through the unloading plate guide post 14 that passes through the lower concave template 4 or the lower concave template 26 and the lower concave mold pad 5. The lower unloading plate 9 and the lower concave mold pad 5 are connected by the unloading plate guide post 14. The lower concave template 4, the lower concave template 26 and the lower concave mold pad 5 are fixedly connected to the lower mold base by bolts.

[0041] In this embodiment, the progressive die structure is a commonly used technique, and any issues not mentioned are addressed using existing technical solutions.

[0042] Example 3

[0043] This implementation is an improvement based on Example 2, specifically as follows:

[0044] like Figure 1-9As shown, a vibration damping and buffering mechanism is also provided between the upper mold and the lower mold. The vibration damping and buffering mechanism includes a support rod 32, a first mounting groove 33, a second mounting groove 29, a first limiting block 36, a second limiting block 35, a first spring 34, and a second spring 30. The support rod 32 extends longitudinally through the upper unloading plate 1 3 or the upper unloading plate 2 8. A first limiting block 36 and a second limiting block 35 are provided at the upper and lower parts of the support rod 32. The bottom end of the first limiting block 36 is in contact with the upper surface of the upper unloading plate 1 3 or the upper unloading plate 2 8, and the top end of the second limiting block 35 is in contact with the lower surface of the upper unloading plate 1 or the upper unloading plate 2 8. The first mounting groove extends through the fixing plate 2 and the upper mold base 1. A first spring 34 is installed in the lower part of the first mounting groove 33. The top end of the first limiting block 35 is in contact with the lower surface of the first unloading plate 1 or the upper unloading plate 2 8. The first mounting groove 29 extends longitudinally through the upper mold base 1. A first spring 30 is installed in the lower part of the first mounting groove 33. A first limiting block 36 is installed in the lower part of the first mounting groove 39. A first limiting block 30 is installed in the lower part of the first limiting block 39. A first limiting block 30 ... The lower end of spring 34 is connected and can partially enter the first mounting groove 33 when the first spring 34 is compressed. The first recessed template 4 or the second recessed template 26 is provided with a second mounting groove 29 at a position perpendicular to the first mounting groove 33. The second mounting groove 29 passes through the first recessed template 4 or the second recessed template 26 and the recessed mold pad 5. The upper part of the second mounting groove 29 is installed with a second spring 30. The bottom end of the second limiting block 35 is connected to the top end of the second spring 30 and can partially enter the second mounting groove 29 when the second spring is compressed. The lower part of the support rod 32 is inserted into the second spring 30. When the first spring 34 and the second spring 30 are in their natural state, the first recessed template 4 and the first upper unloading plate 3, and the second recessed template 26 and the second upper unloading plate 8 are separated from each other.

[0045] In this embodiment, the vibration damping and buffering mechanism assists the upper blanking plate one or upper blanking plate two in blanking on the one hand, and limits the upper blanking plate one and upper blanking plate two on the other hand. At the same time, it can also buffer the impact force during the mold closing process, which is conducive to the chain link obtaining a better forming effect.

[0046] Example 4

[0047] This implementation is an improvement based on Example 3, specifically as follows:

[0048] like Figure 1-9 As shown, the coarse punching station includes a coarse punching pin 15, the bottom of which is fixedly connected to the fixing plate 2, and the top of which slides longitudinally through the lower surface of the upper unloading plate 3; the guiding station includes a guide pin 17, the bottom of which is fixedly connected to the fixing plate 2, and the top of which slides longitudinally through the lower surface of the upper unloading plate 3.

[0049] Example 5

[0050] This implementation is an improvement based on Example 4, specifically as follows:

[0051] like Figure 1-9As shown, the pre-punching station includes an upper die on the upper die plate 10 and a pre-punching punch 13. An ejector 20 is provided inside the upper die. The top of the ejector 20 is slidably connected to a fixed plate 2 and connected to an ejector nitrogen spring 19 embedded in the upper die base 1. The ejector nitrogen spring 19 has a flange on its top, which is fixedly connected to the upper die base 1 by bolts. The ejector nitrogen spring 19 is connected to a balancing nitrogen spring 18 via a high-pressure pipeline 23, forming a management system with the same pressure. The high-pressure pipeline 23 is also connected to a shock-resistant pressure gauge 11. The balancing nitrogen spring 18 is arranged inside the upper die base 1, and a set bolt 12 is provided on the outside of the compression rod of the balancing nitrogen spring 18. The system pressure is increased or decreased by adjusting the set bolt 12, thereby changing the pressure output of the ejector nitrogen spring 19 at the top of the ejector 20. The lower end of the ejector is used to flatten the upper end of the pre-punched part 24. The upper surface of the lower die base 6 is also provided with a first mounting hole, in which a rectangular helical spring 21 is provided. The top end of the rectangular helical spring is connected to a guide post 25. The guide post slidably passes through the lower die pad and is fixedly connected to the lower stripper plate. In the open state, the lower surface of the lower stripper plate is separated from the upper surface of the lower die pad. The lower end of the pre-punch punch is fixedly connected to the upper surface of the lower die pad, and the upper end slidably passes through the upper surface of the lower stripper plate along the longitudinal direction. A rectangular helical spring and a guide post assist the lower unloading plate in unloading and buffering the impact force. During compression, the guide post moves downward and the rectangular helical spring is compressed and shortened. When the mold opens, the rectangular helical spring lifts the lower unloading plate to drop the material. The cutting edge of the upper die is used to form the first rounded corner band 004.

[0052] In this embodiment, adjustments can be made according to actual usage. A pressure detection sensor 22 is installed in the high-pressure pipeline. The pressure detection sensor 22 is connected to the brake control circuit of the press through a wire. When the system pressure is lower than required, the press stops.

[0053] Example 6

[0054] This implementation is an improvement based on Example 5, specifically as follows:

[0055] like Figure 1-7 As shown, the fine punching station includes a fine punching pin (not shown in the figure), the bottom of which is fixedly connected to the fixed plate 2, and the top of which slides longitudinally through the lower surface of the upper unloading plate 2 8; the guiding station 2 includes a guide pin 17, the bottom of which is fixedly connected to the fixed plate 2, and the top of which slides longitudinally through the lower surface of the upper unloading plate 2 8.

[0056] Example 7

[0057] This implementation is an improvement based on Example 6, specifically as follows:

[0058] like Figure 1-9 As shown, the blanking station includes a blanking punch 37, the upper end of which is fixedly connected to the lower surface of the fixed plate 2, and the lower end of which slides longitudinally through the lower surface of the upper unloading plate 8. The lower surface of the upper die base 1 is also provided with a mounting hole 2, in which a rectangular helical spring 2 is installed. A pressure rod is connected to the bottom end of the rectangular helical spring 2, and the pressure rod slides through the fixed plate and is fixedly connected to the upper unloading plate 8. In the open die state, the upper surface of the upper unloading plate 2 is separated from the lower surface of the fixed plate (the rectangular helical spring 2 and the pressure rod assist the upper unloading plate 2 in unloading and buffer the impact force). A blanking hole (not shown in the figure) is provided in the lower die below the blanking punch 37. The shape and size of the blanking hole match the shape and size of the formed chain piece, and the blanking hole... The upper end opens onto the upper surface of the lower concave template 26, and the lower end penetrates the lower concave die pad and the lower die base 6, forming a blanking part outlet on the lower surface of the lower die base; the top of the blanking hole is provided with a blanking punch die (not shown in the figure) for use with the blanking punch; the blanking punch has a receiving cavity (not shown in the figure) inside, and the receiving cavity is connected to a cooling and lubricating medium supply device under pressure (not shown in the figure); several spray holes (not shown in the figure) are evenly distributed around the axis in the middle of the side wall of the blanking punch; during the blanking process, the supply device pumps the cooling and lubricating medium directly into the cutting edge of the blanking punch die through the spray holes for lubrication and cooling, and at the same time flushes away the blanking material (debris generated by the blanking of the strip) adhering to the blanking punch; the cutting edge of the blanking punch die is used to form the second rounded corner strip 005.

[0059] Example 8

[0060] This implementation is an improvement based on Example 7, specifically as follows:

[0061] The blanking clearance between the cutting edge of the pre-punch punch 13 in the pre-punch station 04 and the cutting edge of the upper die of the upper die plate 10 is as follows: the cutting edge size L1 of the pre-punch punch is greater than the cutting edge size L2 of the upper die, and the relationship satisfies: △L=L1-L2, where △L is 2%-3% of the strip thickness. This design is to reserve allowance for the rounded corners on the lower surface of the part. The cutting edge size L2 of the upper die is greater than the cutting edge size H of the blanking punch die of the lower die plate 26, and the relationship satisfies: L2>H, with a difference of 0.03mm.

Claims

1. A chain link blank profile double-round corner burr-free blanking device, characterized by: The device includes a progressive die body, comprising an upper die and a lower die. The strip passes between the upper and lower dies. Along the strip's path, from left to right, are arranged the following stations: a rough punching station, a first guiding station, a pre-punching station, a fine punching station, a second guiding station, and a blanking station. The cutting edge of the upper die in the pre-punching station is used to punch out the first rounded corner at the upper edge of the pre-punched part. Simultaneously, the blanking station uses the cutting edge of the blanking punch die to punch out the second rounded corner at the lower edge of the blanked part. The punching clearance between the cutting edge of the pre-punching punch and the cutting edge of the upper die in the pre-punching station is such that the cutting edge size L1 of the pre-punching punch is greater than the cutting edge size L2 of the upper die, satisfying the relationship: ΔL = L1 - L2, where △L is 2%-3% of the strip thickness, the cutting edge size L2 of the upper die is greater than the cutting edge size H of the blanking punch die, the relationship satisfies: L2>H, difference: 0.03mm; The pre-punching station includes an upper die and a pre-punching punch located on the upper die plate. An ejector is installed inside the upper die, with a slidable through-plate at its top end connected to an ejector nitrogen spring embedded in the upper die base. The ejector nitrogen spring has a flange at its top, which is bolted to the upper die base. The ejector nitrogen spring is connected to a balancing nitrogen spring via a high-pressure pipeline, forming a management system with the same pressure. The high-pressure pipeline is also connected to a shock-resistant pressure gauge. The balancing nitrogen spring is arranged inside the upper die base, and a set bolt is located on the outside of its compression rod. Adjusting the set bolt increases or decreases the system pressure, thus changing the ejector pressure. The nitrogen spring outputs pressure at the top of the ejector; the lower end of the ejector is used to apply pressure and level the pre-punched part; the upper surface of the lower die base is also provided with a first mounting hole, a rectangular helical spring is provided in the first mounting hole, the top end of the rectangular helical spring is connected to a guide post, the guide post can slide through the lower die pad and is fixedly connected to the lower stripper plate. In the open state, the lower surface of the lower stripper plate is separated from the upper surface of the lower die pad, the lower end of the pre-punch punch is fixedly connected to the upper surface of the lower die pad, and the upper end can slide longitudinally through the upper surface of the lower stripper plate. The cutting edge of the upper die is used to form the first rounded corner strip. The blanking station includes a blanking punch, the upper end of which is fixedly connected to the lower surface of a fixed plate, and the lower end of which slides longitudinally through the lower surface of the upper unloading plate. The lower surface of the upper die base is also provided with a mounting hole, and a rectangular helical spring is installed within the mounting hole. A pressure rod is connected to the bottom end of the rectangular helical spring, and the pressure rod slides through the fixed plate and is fixedly connected to the upper unloading plate. In the open die state, the upper surface of the upper unloading plate is separated from the lower surface of the fixed plate. A blanking hole is provided in the lower die below the blanking punch. The shape and size of the blanking hole match the shape and size of the formed chain link part, and the upper end of the blanking hole is open. The blanking hole is located on the upper surface of the second blanking template, and its lower end penetrates the lower blanking die pad and the lower die base, forming a blanking part outlet on the lower surface of the lower die base. The top of the blanking hole is provided with a blanking punch die for use with the blanking punch. The blanking punch has a receiving cavity inside, which is connected to a cooling and lubricating medium supply device under pressure. Several spray holes are evenly distributed around the axis in the middle of the side wall of the blanking punch. During the blanking process, the supply device pumps the cooling and lubricating medium directly into the cutting edge of the blanking punch die through the spray holes for lubrication and cooling, while flushing away the blanking material adhering to the blanking punch. The cutting edge of the blanking punch die is used to form the second rounded corner strip.

2. A chain link blanking device according to claim 1, wherein: the chain link blank is a double round cornered, burr free blank having a cross section as shown in Fig.

1. The upper mold includes an upper mold base and a fixing plate connected to the lower end of the upper mold base. From left to right, the lower end of the fixing plate has an upper stripper plate 1, an upper concave mold plate, and an upper stripper plate 2 arranged side-by-side. The lower mold includes a lower mold base, a lower concave mold pad connected to the upper end of the lower mold base, and lower concave mold plates 1, a lower stripper plate, and a lower concave mold plate 2 arranged side-by-side on the upper end of the lower concave mold pad. The lower concave mold plate 1 and the upper stripper plate 1 are vertically opposite each other, and a rough punching station and a guiding station 1 are formed sequentially between the upper stripper plate 1 and the lower concave mold plate 1. The upper concave mold plate and the lower stripper plate are vertically opposite each other, and a pre-punching station is formed between the upper concave mold plate and the lower stripper plate. The upper stripper plate 2 and the lower concave mold plate 2 are vertically opposite each other, and a fine punching station, a guiding station 2, and a blanking station are formed between the upper stripper plate 2 and the lower concave mold plate 2. The fixed plate, the upper concave template, and the lower end face of the upper mold base are fixedly connected by bolts. The upper unloading plate one and the upper unloading plate two are respectively connected to the lower mold base by unloading plate guide posts that penetrate the lower concave template one or the lower concave template and the lower concave mold pad. The lower unloading plate and the lower concave mold pad are connected by unloading plate guide posts. The lower concave template one, the lower concave template two, and the lower concave mold pad are fixedly connected to the lower mold base by bolts.

3. The chain link cross-section double-rounded corner burr-free punching device as described in claim 2, characterized in that: A vibration damping and buffering mechanism is also provided between the upper mold and the lower mold. The vibration damping and buffering mechanism includes a support rod, a first mounting groove, a second mounting groove, a first limiting block, a second limiting block, a first spring, and a second spring. The support rod extends longitudinally through either the first or second upper unloading plate. A first limiting block and a second limiting block are provided at the top and bottom of the support rod. The bottom end of the first limiting block is in contact with the upper surface of either the first or second upper unloading plate, and the top end of the second limiting block is in contact with the lower surface of either the first or second upper unloading plate. The first mounting groove extends through the fixing plate and the upper mold base. A first spring is installed in the lower part of the first mounting groove, and the top end of the first limiting block is in contact with the lower surface of the first mold. The lower end of the spring is connected and can partially enter the first mounting groove when the first spring is compressed. The first or second recessed template is provided with a second mounting groove at a position perpendicular to the first mounting groove. The second mounting groove passes through the first or second recessed template and the recessed mold pad. The upper part of the second mounting groove is installed with a second spring. The bottom end of the second limiting block is connected to the top end of the second spring and can partially enter the second mounting groove when the second spring is compressed. The lower part of the support rod is inserted into the second spring. When the first spring and the second spring are in their natural state, the first recessed template and the first upper unloading plate are separated from each other; the second recessed template and the second upper unloading plate are separated from each other.

4. The chain link cross-section double-rounded corner burr-free punching device as described in claim 3, characterized in that: The coarse punching station includes a coarse punch pin, the bottom of which is fixedly connected to a fixed plate, and the top of which slides longitudinally through the lower surface of the upper unloading plate. The guiding station includes a guide pin, the bottom of which is fixedly connected to a fixed plate, and the top of which slides longitudinally through the lower surface of the upper unloading plate.

5. The chain link cross-section double-rounded corner burr-free punching device as described in claim 4, characterized in that: The fine punching station includes a fine punching pin, the bottom of which is fixedly connected to a fixed plate, and the top of which slides longitudinally through the lower surface of the upper unloading plate 2; the guiding station 2 includes a guide pin, the bottom of which is fixedly connected to a fixed plate, and the top of which slides longitudinally through the lower surface of the upper unloading plate 2.

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