Cold heading device for special-shaped bolt

Abstract

The utility model relates to a cold heading device for a special-shaped bolt. The cold heading device comprises a cutting mechanism, an ejection mechanism, a conveying mechanism and five dies, the conveying mechanism moves between the ejection mechanism and the six molds for feeding; the first upsetting die is used for enabling an initial blank to form an upper section and a lower section, and the diameter of the upper section is larger than that of the lower section; the second upsetting die is used for primarily flattening the upper section of the first blank and enabling the upper end of the upper section to form a conical top; the three-upsetting die is used for enabling the upper section of the second blank to form a head which is further flattened and provided with a conical top at the upper end, and octagonal forming; the four-upsetting die is used for enabling the upper end of the flattened head of the third blank to form a hexagonal top with a conical top, enabling the middle end of the head to form a disc, enabling the lower end of the head to form a flat circular-truncated-cone-shaped positioning step, and keeping octagonal; the cutting die is used for cutting off redundant materials of the fourth blank disc; each of the six molds comprises a lower mold and an upper mold, the lower mold comprises a lower mold shell and a lower mold core, the lower mold core is arranged in the lower mold shell, and a main mold cavity is formed in the lower mold core.

Description

Technical Field

[0001] This utility model belongs to the field of cold heading technology for bolts, and specifically relates to a cold heading device for irregularly shaped bolts. Background Technology

[0002] In existing technologies, electrical connections in battery packs often employ a bolt assembly integrating welding and wiring functions. The bolt head is designed with a conical apex structure for easy welding and fixing; the head also features a hexagonal structure for wrench assembly; and the connection between the bolt and the head is an octagonal structure for engaging with the wiring coil. In the assembly process, the bolt and matching nut are typically assembled into a unit, then welded to the designated location on the battery pack housing. Following this, an overall electrophoretic coating is applied to form an insulating layer on the component's surface. During wiring, the nut is removed, and the coil is fitted onto the octagonal structure. However, this existing technology has the following significant drawbacks: the diagonals of the traditionally molded octagonal and hexagonal structures are often quite rounded, directly leading to two core problems: poor contact due to slippage during octagonal wiring, and reduced efficiency due to slippage during hexagonal pre-assembly. Utility Model Content

[0003] In summary, to overcome the shortcomings of the prior art, this utility model provides a cold heading device for irregularly shaped bolts.

[0004] To achieve the above objectives, this utility model provides the following technical solution: a cold heading device for irregularly shaped bolts, comprising a cutting mechanism, an ejection mechanism, a conveying mechanism, and five molds, wherein the cutting mechanism cuts the blank, the ejection mechanism lifts the blank, and the conveying mechanism moves between the ejection mechanism and the six molds to feed material; the five molds include: a first heading mold for forming an initial blank into upper and lower segments with the upper segment diameter larger than the lower segment diameter; a second heading mold for initially flattening the upper segment of the first blank and forming a conical apex at the upper end of the upper segment; and so on. A three-die mold for further flattening the upper section of the second blank into a head with a conical top and an octagonal shape; a four-die mold for flattening the third blank into a head with a hexagonal top with a conical top, a disc in the middle of the head, and a flat frustum-shaped positioning step at the lower end of the head while maintaining the octagonal shape; and a cutting die for removing excess material from the disc of the fourth blank; each of the six dies includes a lower die and an upper die. The lower die includes a lower die shell, a lower die core, and a lower die punch. The lower die core is located inside the lower die shell and has a main mold cavity inside.

[0005] By adopting the above technical solution, in the existing cold heading process, when forming an octagon, the material mainly comes from the lower rod. The mold squeezes and expands the rod material with a smaller diameter upwards to fill the mold cavity of the octagon, especially the pointed areas at the opposite corners. This is because the material is transferred from a local area (rod diameter) to a large area (octagon). Due to the inherent flow characteristics of metals, especially given the long flow distance and high resistance, material often fails to fully fill the sharp corners of the octagon, resulting in a rounded, uneven shape after forming. In this invention, the first upsetting die shapes the initial blank into a first blank with a significantly larger upper diameter than the lower diameter. This ensures sufficient, even excessive, material in the upper section for forming the head and octagons. This "larger at the top, smaller at the bottom" structure provides a solid volume foundation for the subsequent "head pressing" process, ensuring ample material for forming. The second upsetting die initially forms the head cone, while the third and fourth upsetting dies gradually shape the shape, resulting in more uniform metal flow. The third upsetting die, after the head of the blank has been initially flattened, performs the final forming of the octagonal structure. Because the upper section has ample material, it ensures the sharpness and definition of the octagonal edges after forming. The new technology features clear, precise dimensions and sharp outlines. It eliminates the problem of rounded octagonal corners caused by "material extrusion and insufficient flow filling" in the old process. The octagons formed in this technology are full and sharp, and can achieve tight, slip-free contact with the connecting coil, improving the reliability and safety of electrical connections. After the head of the third blank is flattened by the four-upsetting mold and formed into a hexagonal top with a conical apex, the excess material forms a disc between the hexagon and the octagon (a non-standard disc is formed during the four-upsetting mold, and it is disc-shaped when the material is finally cut and formed, that is, only the thickness of the forming is controlled but the outer circumference of the remaining material is not controlled, and it is referred to as "disc" for convenience). This ensures that the edges and corners of the hexagon are clear and the outline is distinct. This allows the wrench or socket to be firmly engaged when tightening, and eliminates tool slippage during pre-assembly or later maintenance.

[0006] The present invention further comprises: the main mold cavity of the upsetting mold includes an upper forming cavity for forming the upper section of the first blank and a lower forming cavity for forming the lower section of the first blank; a transition cavity with a larger upper section and a smaller lower section is provided between the upper forming cavity and the lower forming cavity; and the upper end of the lower die punch of the upsetting mold extends into the lower forming cavity.

[0007] By adopting the above technical solution, two independent cavities precisely control the diameter and volume of the upper section and the diameter of the lower section. The diameter of the upper cavity is significantly larger than that of the lower cavity, which ensures that sufficient material volume is precisely pre-positioned at the head position during the initial molding. This "larger at the top and smaller at the bottom" initial blank structure lays a solid volume foundation for the subsequent "head pressing" process, ensuring sufficient material for molding. The transition cavity is located in the transition area between the upper and lower molding cavities. The "larger at the top and smaller at the bottom" conical or arc-shaped transition can smoothly guide the metal to flow from the upper section to the lower section during deformation, avoiding severe shearing and stress concentration caused by abrupt changes in cross-section. This makes the metal fiber flow more continuous, reduces the risk of internal defects such as folds and cracks, and improves the internal quality and mechanical strength of the blank. The smooth transition reduces the impact and wear of metal on the sharp corners of the mold cavity, which is beneficial to extending the service life of the mold.

[0008] The present invention further comprises: the main mold cavity of the two upsetting mold includes an upper forming cavity for forming a truncated cone with a larger upper part and a smaller lower part at the lower end of the upper section of the second blank, and a lower forming cavity for forming the rod part of the second blank. The upper end of the lower die punch of the two upsetting mold extends into the lower forming cavity of the two mold. The upper mold of the two upsetting mold includes an upper die core. The lower end of the upper die core is provided with a top cavity for forming a truncated cone with a smaller upper part and a larger lower part at the upper end of the upper section of the second blank.

[0009] By adopting the above technical solution, the first blank formed in one upsetting is an upper cylinder, a middle transition frustum, and a lower rod. The upper forming cavity of the second mold forms the upper cylinder and frustum into a frustum with a larger upper part and a smaller lower part. The top cavity of the second mold forms the top of the upper cylinder into a frustum with a conical apex, which is smaller at the top and larger at the bottom. Through the two upper and lower cavities of the second upsetting mold, the upper material of the first blank is formed into two frustums with opposite conical shapes in advance, which are used for the subsequent forming of the conical apex, hexagon, and disc and octagon. In the same process, but through different cavity areas, the process is completed separately, which significantly reduces the complexity of metal deformation and local stress in the mold, optimizes the internal metal flow lines and structure, lays the foundation for full forming, reduces the difficulty of single forming and stress concentration, and improves quality and mold life.

[0010] The present invention further comprises: the upper mold of the three-die mold includes a three-die upper mold core, the lower end of the three-die upper mold core is provided with a three-die top cavity for forming a three-die top cavity with a cone top and a smaller upper and larger lower truncated cone at the upper end of the upper section of the third blank, the cone top height of the three-die top cavity is less than the cone top height of the two-die top cavity, and the lower end diameter of the three-die top cavity is greater than the lower end diameter of the two-die top cavity.

[0011] By adopting the above technical solution, the uppermost conical apex of the blank head is further flattened, reducing its axial height. Excess material in the upper conical apex area is then "spread" downwards and laterally, filling the area of ​​the truncated cone (smaller at the top, larger at the bottom). This is equivalent to a crucial "pre-compression" and "volume redistribution" of the material in the main body of the head before the hexagon is formally formed, making it thicker and larger in diameter, laying a sufficient volume foundation for the subsequent hexagonal forming. The top cavity of the third mold also refines and shapes the conical apex pre-formed in the second upsetting process. Step-by-step forming achieves higher shape accuracy, better corner clarity, and more stable surface quality than single-stage direct forming, ensuring the uniformity and connection strength of the weld during subsequent welding. It also optimizes the internal structure, making the material in the conical apex area denser, eliminating the risk of internal defects, and thus enhancing the structural strength of this critical load-bearing component. Simultaneously, it disperses forming stress and deformation, reducing mold wear and improving stability, extending mold life.

[0012] The present invention further comprises: the main mold cavity of the three-die mold includes, from bottom to top, a three-die lower forming cavity for forming the rod part of the third blank, a three-die octagonal forming cavity for forming the octagon of the third blank, and a three-die upper residual material cavity for accommodating the lower end of the head of the third blank and the octagonal material cutting. The minimum diameter of the three-die upper residual material cavity is greater than the maximum diameter of the two-die upper forming cavity. The upper end of the lower die punch of the three-die mold extends into the three-die lower forming cavity.

[0013] By adopting the above technical solution, the lower forming cavity of the three molds precisely constrains the dimensions of the rod, while the upper end of the lower mold punch extends into it, providing rigid support and precise axial positioning for the entire blank from bottom to top; the octagonal forming cavity of the three molds enables the precise forming of the octagon of the third blank. Since there is a material surplus cavity of the upper mold above, it provides space for material flow and redistribution, allowing excess material to enter the material surplus cavity of the upper mold, avoiding the material from being trapped or folded in the octagonal cavity of the three molds due to having nowhere to go. This ensures that the octagonal cavity, especially the diagonal tips, can be filled with a continuous, stable, and sufficient flow of material, ultimately forming a full-edged octagon. The material surplus cavity of the upper mold plays the role of "pressure relief" and "guidance".

[0014] This utility model further includes the following: the upper mold of the four-die upsetting mold includes an upper die core and an upper die punch. The upper die core includes a forming through hole for cutting the third blank with a cone-shaped top (small upper, large lower) into a hexagon. The lower end of the upper die punch has a conical cavity for protecting the cone-shaped top of the fourth blank. The lower end of the upper die punch extends into the forming through hole. The main mold cavity of the four-die upsetting mold includes, from bottom to top, a lower receiving cavity for accommodating the rod of the fourth blank, a middle receiving cavity for accommodating the octagon and the upper end of the rod of the fourth blank, and a forming cavity for forming a positioning step. The diameter of the middle receiving cavity is larger than the diameter of the octagonal forming cavity. A forming gap for forming the remaining material is provided between the upper and lower molds of the four-die upsetting mold.

[0015] By adopting the above technical solution, the cooperation between the forming through hole on the four-die upper mold and the upper mold punch enables cold heading and simultaneous edge trimming of the upper part of the blank head material, directly forming a hexagon. Compared with machining, this is not only highly efficient, but also improves the surface hardness and strength of the hexagonal part, making it more wear-resistant and anti-slip during twisting. The tapered cavity at the lower end of the upper mold punch accurately accommodates and protects the formed cone tip during stamping, preventing deformation or damage when subjected to huge cutting force, ensuring the integrity of the welding functional surface. The forming cavity on the four-die upper mold forms a flat frustum-shaped positioning step at the lower end of the head, facilitating the positioning of the subsequent disc cutting and avoiding the cutting edge being smaller than the positioning step (if the cutting edge is smaller than the positioning step, the electrophoretic paint will penetrate in the subsequent electrophoretic process, leading to...). The bolt support surface has an insulating layer (non-conductive), resulting in higher precision and stability, and better product molding quality. The diameter of the middle cavity is larger than that of the three-mold octagonal molding cavity, providing a spacious and interference-free space for the already formed octagon, effectively preventing the octagon from being deformed by accidental compression, and perfectly protecting the sharp octagonal shape and dimensional accuracy obtained in the previous processes. The molding gap between the upper and lower molds is used to accommodate excess material during the hexagonal cutting and positioning step molding process. The excess material forms a "disc" in the molding gap. The thickness of the "disc" is controlled by setting the height of the molding gap, but the burrs of the "disc" are removed in the next process. Four-up forming results in high precision and good stability.

[0016] The present invention further comprises: the lower end inner cavity of the forming through hole on the four molds is hexagonal prism-shaped; the upper end diameter of the forming through hole on the four molds is larger at the top and smaller at the bottom; and the lower end diameter of the upper mold punch is smaller than the minimum diameter of the forming through hole on the four molds.

[0017] By adopting the above technical solution, the hexagonal columnar portion of the lower end cavity of the upper forming through hole determines key dimensions such as the distance between opposite sides and the diagonal. By precisely limiting this area to the lower end and ensuring its machining accuracy, the dimensions of the formed hexagon strictly conform to the design, thereby solving the problem of slippage during twisting. The upper diameter of the upper forming through hole is designed in a flared shape with a larger diameter at the top and a smaller diameter at the bottom, which serves to avoid air gaps. The contact area between the inner wall of the mold and the hexagonal columnar surface of the workpiece is limited to the very short forming area at the bottom, which significantly reduces the risk of the hexagonal surface of the workpiece being scratched by the inner wall of the mold and also reduces the wear of the mold cavity, thereby improving the surface quality of the product and the service life of the mold. The lower diameter of the upper die punch is smaller than the minimum diameter of the upper forming through hole of the four dies, which facilitates material discharge and ensures high stability.

[0018] The present invention further comprises: the upper mold of the cutting mold includes an upper mold shell and a cutting upper cutting die core for cutting off excess material along the outer periphery of the positioning step to form a disc; the cutting upper cutting die core is hollow and has a discharge through hole; the diameter of the discharge through hole is larger than the diameter of the forming cavity of the upper mold; and the upper mold shell is provided with a discharge channel adapted to the discharge through hole.

[0019] By adopting the above technical solution, the upper cutting die core cuts downwards along the outer periphery of the "flat frustum-shaped positioning step" that has been initially formed on the fourth blank, removing excess material from the "disc". This results in a precisely sized and clearly defined disc. Through the precise guidance and cutting of the upper cutting die core, it is ensured that the cutting action only acts on the excess material that needs to be removed, without scratching or squeezing the already precision-machined hexagonal, octagonal, conical apex, and rod parts, thus perfectly protecting all the forming results of the previous four stages. The diameter of the discharge through hole is larger than the diameter of the forming cavity on the fourth die, and the upper die shell is equipped with a discharge channel that matches the discharge through hole, allowing the workpiece to be discharged smoothly and without obstruction. The material is convenient to discharge, and the cutting and discharge are achieved in the same die, resulting in high production efficiency.

[0020] The present invention further comprises: a sliding mold core is provided inside the main mold cavity of the cutting mold; the lower end of the sliding mold core is located outside the main mold cavity of the cutting mold and an operating part is provided on its outer periphery; a first spring is provided between the operating part and the lower mold core of the cutting mold; an outer push rod is provided below the sliding mold core for pushing the sliding mold core to move; the sliding mold core is provided with an octagonal and rod-shaped receiving channel for accommodating the fifth blank; an active cavity for accommodating the second spring and the inner push rod is provided inside the outer push rod; the inner push rod includes a push head located in the active cavity and a push rod part connected to the push head at one end and located in the receiving channel at the other end; the second spring is located at the other end of the push head opposite the sliding mold core.

[0021] By adopting the above technical solution, the receiving channel of the sliding mold core precisely matches the octagonal and rod shapes of the fifth blank, firmly positioning and protecting the workpiece during the cutting process. This ensures that the cutting force only acts on the flash to be removed (the remaining material on the outer periphery of the disc), without causing any extrusion deformation or scratches on the precision-formed octagonal, hexagonal, or other parts. First, the upper and lower molds close to clamp the disc. Then, the outer push rod overcomes the resistance of the first spring, pushing the sliding mold core to move and eject the workpiece into the discharge through hole. This causes relative displacement between the disc and the cutting mold core, completing the flash removal. The finished workpiece enters the through hole. After cutting is complete, the inner push rod loses its limit, and the compressed second spring resets, driving the inner push rod to push the workpiece into the discharge channel for ejection. After ejection, the outer push rod retracts, and the sliding mold core automatically resets to its initial position under the action of the first spring, ready for the next work cycle. The entire ejection and reset process requires no manual intervention and is precise and reliable.

[0022] The embodiments describe specific implementations of this utility model. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the step-by-step cold heading process of the blank in an embodiment of this utility model.

[0024] Figure 2 This is a schematic diagram of the workpiece according to an embodiment of the present utility model.

[0025] Figure 3 This is a cross-sectional view of the cold heading device according to an embodiment of the present invention.

[0026] Figure 4 for Figure 3 Enlarged view of part A.

[0027] Figure 5 for Figure 3 Enlarged view of part B.

[0028] Figure 6 for Figure 3 Enlarged view of part C.

[0029] Figure 7 This is a cross-sectional view of the cutting die according to an embodiment of the present invention.

[0030] Figure 8 This is a schematic diagram showing the changes in the mold closing mechanism of the cutting mold according to an embodiment of this utility model.

[0031] Reference numerals: 1. First upsetting mold; 11. Main mold cavity of the first upsetting mold; 111. Upper forming cavity of the first mold; 112. Transition cavity; 113. Lower forming cavity of the first mold; 2. Second upsetting mold; 21. Lower mold of the second upsetting mold; 211. Lower mold shell of the second upsetting mold; 212. Main mold cavity of the second upsetting mold; 2121. Upper forming cavity of the second mold; 2122. Lower forming cavity of the second mold; 212. Lower die punch of the second upsetting mold; 22. Upper die of the second upsetting mold; 221. Upper die core of the second mold; 2211. Second... 3. Three-upsetting mold, 31. Lower mold of the three-upsetting mold, 311. Lower mold shell of the three-upsetting mold, 312. Main mold cavity of the three-upsetting mold, 3121. Lower forming cavity of the three-upsetting mold, 3122. Octagonal forming cavity of the three-upsetting mold, 3123. Upper material cavity of the three-upsetting mold, 32. Upper mold of the three-upsetting mold, 321. Upper mold core of the three-upsetting mold, 3211. Top cavity of the three-upsetting mold; 4. Four-upsetting mold, 41. Lower mold of the four-upsetting mold, 411. Lower mold shell of the four-upsetting mold, 412. Main mold cavity of the four-upsetting mold. 4121. Lower receiving cavity; 4122. Middle receiving cavity; 4123. Upper forming cavity of the fourth die; 42. Upper die of the fourth upsetting die; 421. Upper cutting die core of the fourth die; 4211. Forming through hole of the fourth die; 422. Upper die punch; 4221. Conical cavity; 43. Forming gap; 5. Cutting die; 51. Lower die of the cutting die; 511. Lower die shell of the cutting die; 512. Lower die core of the cutting die; 5121. Main mold cavity of the cutting die; 513. Sliding die core; 5131 5132. Operating section; 514. Receiving channel; 515. First spring; 516. Outer push rod; 517. Movable cavity; 518. Inner push rod; 519. Push head; 5102. Push rod section; 511. Second spring; 52. Upper die of cutting mold; 521. Upper die shell; 5211. Discharge channel; 522. Upper cutting die core; 5221. Discharge through hole; 6. Blank; 61. Conical apex; 62. Hexagon; 63. Disc; 64. Positioning step; 65. Octagon; 66. Rod section. Detailed Implementation

[0032] This specific embodiment is merely an explanation of the present utility model and is not intended to limit the present utility model. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present utility model, they are protected by patent law.

[0033] See appendix Figure 1-8This embodiment discloses a cold heading device for irregularly shaped bolts, including a cutting mechanism, an ejection mechanism, a conveying mechanism, and five molds. The cutting mechanism cuts the blank, and the ejection mechanism lifts the blank. The conveying mechanism moves between the ejection mechanism and the six molds to feed the blank. The five molds include: a first heading mold 1 for forming an initial blank into upper and lower segments with the upper segment diameter larger than the lower segment diameter; a second heading mold 2 for initially flattening the upper segment of the first blank and forming a conical apex at the upper end of the upper segment; and a third heading mold 2 for forming a second blank... The upper section forms a head with a conical top for further flattening and an octagonal three-upsetting mold; the upper end of the head for flattening the third blank forms a hexagonal top with a conical top, the middle end of the head forms a disc, and the lower end of the head forms a flat frustum-shaped positioning step while maintaining the octagonal shape; a cutting mold for removing excess material from the fourth blank disc; all six molds include a lower mold and an upper mold, the lower mold includes a lower mold shell, a lower mold core and a lower mold punch, the lower mold core is located inside the lower mold shell, and the lower mold core has a main mold cavity.

[0034] This embodiment further includes the following configuration: the main mold cavity 11 of the upsetting mold includes an upper forming cavity 111 for forming the upper section of the first blank and a lower forming cavity 113 for forming the lower section of the first blank. A transition cavity 112 with a larger upper section and a smaller lower section is provided between the upper forming cavity 111 and the lower forming cavity 113. The upper end of the lower die punch of the upsetting mold extends into the lower forming cavity 113.

[0035] This embodiment further includes the following configuration: the main mold cavity 212 of the second upsetting mold includes an upper forming cavity 2121 for forming a truncated cone with a larger upper part and a smaller lower part at the lower end of the upper section of the second blank, and a lower forming cavity 2122 for forming the rod part of the second blank. The upper end of the lower die punch of the second upsetting mold 2 extends into the lower forming cavity 2122. The upper mold 22 of the second upsetting mold includes an upper die core 221. The lower end of the upper die core 221 is provided with a top cavity 2211 for forming a truncated cone with a smaller upper part and a larger lower part at the upper end of the upper section of the second blank.

[0036] This embodiment further includes the following configuration: the upper mold 32 of the three-die mold includes a three-die upper mold core 321. The lower end of the three-die upper mold core 321 is provided with a three-die top cavity 3211 for forming a truncated cone with a smaller upper cone and a larger lower cone at the upper end of the upper section of the third blank. The cone height of the three-die top cavity 3211 is less than the cone height of the two-die top cavity 2211, and the lower diameter of the three-die top cavity 3211 is greater than the lower diameter of the two-die top cavity 2211.

[0037] This embodiment further includes the following configuration: the main mold cavity 312 of the three-die mold includes, from bottom to top, a three-die lower forming cavity 3121 for forming the rod part of the third blank, a three-die octagonal forming cavity 3122 for forming the octagon of the third blank, and a three-die upper waste material cavity 3123 for accommodating the lower end of the head of the third blank and the octagonal material cutting. The minimum diameter of the three-die upper waste material cavity 3123 is greater than the maximum diameter of the two-die upper forming cavity 2121. The upper end of the lower die punch of the three-die mold 3 extends into the three-die lower forming cavity 3121.

[0038] This embodiment further includes the following configuration: the upper die 42 of the four-die upsetting mold comprises a four-die upper cutting die core 421 and an upper die punch 422. The four-die upper cutting die core 421 includes a four-die upper forming through hole 4211 for cutting the third blank with a conical top (smaller upper and larger lower truncated cone) into a hexagon. The lower end of the upper die punch 422 is provided with a conical cavity 4221 for protecting the conical top of the fourth blank. The lower end of the upper die punch 422 extends into the four-die upper forming through hole 4211. The main mold cavity 412 of the four-upsetting mold includes, from bottom to top, a lower receiving cavity 4121 for accommodating the fourth blank rod, a middle receiving cavity 4122 for accommodating the octagonal part of the fourth blank and the upper end of the rod, and a fourth mold upper forming cavity 4123 for forming the positioning step. The diameter of the middle receiving cavity 4122 is larger than the diameter of the octagonal forming cavity 3122. A forming gap 43 for forming the remaining material is provided between the upper mold 42 and the lower mold 41 of the four-upsetting mold.

[0039] In this embodiment, the lower end of the inner cavity of the forming through hole 4211 on the four molds is set in a hexagonal column shape, the upper end diameter of the forming through hole 4211 on the four molds is set to be larger at the top and smaller at the bottom, and the lower end diameter of the upper mold punch 422 is smaller than the minimum diameter of the forming through hole 4211 on the four molds.

[0040] This embodiment further includes the following configuration: the upper mold 52 of the cutting mold includes an upper mold shell 521 and a cutting upper mold core 522 for cutting off excess material along the outer periphery of the positioning step to form a disk. The cutting upper mold core 522 is hollow and has a discharge through hole 5221. The diameter of the discharge through hole 5221 is larger than the diameter of the upper forming cavity 4123 of the fourth mold. The upper mold shell 521 is provided with a discharge channel 5211 that matches the discharge through hole 5221.

[0041] This embodiment further includes the following configuration: a sliding mold core 513 is provided inside the main mold cavity 5121 of the cutting mold. The lower end of the sliding mold core 513 is located outside the main mold cavity 5121 of the cutting mold, and an operating part 5131 is provided on its outer periphery. A first spring 514 is provided between the operating part 5131 and the lower mold core 512 of the cutting mold. An external push rod 515 for pushing the sliding mold core 513 to move is provided below the sliding mold core 513. There is an octagonal receiving channel 5132 for accommodating the fifth blank and the rod portion. The outer push rod 515 is provided with a movable cavity 5151 for accommodating the second spring 517 and the inner push rod 516. The inner push rod 516 includes a push head 5161 disposed in the movable cavity 5151 and a push rod portion 5162 with one end connected to the push head 5161 and the other end disposed in the receiving channel 5132. The second spring 517 is disposed at the other end of the push head 5161 relative to the sliding mold core 513.

[0042] The present invention does not limit whether the final forming of the rod is a straight screw blank or a multi-segment shortened screw blank. Production is carried out according to customer needs. Therefore, the technical solution on how to form a multi-segment shortened screw blank is not elaborated, but is only used as an illustration in the embodiment.

[0043] In the description of this utility model, it should be noted that "upper mold" refers to a movable mold and "lower mold" refers to a fixed mold. The terms "upper," "middle," and "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. The "between" mentioned above does not only refer to the orientation or position, but also includes the interaction between different parts.

[0044] The use of these terms is merely for the convenience of describing and explaining the essence of this utility model; interpreting them as any kind of additional limitation would be contrary to the spirit of this utility model.

Claims

1. A cold heading device of a profile bolt, comprising a cutting mechanism, an ejection mechanism, a conveying mechanism and five dies, wherein, The cutting mechanism cuts the blank, the ejecting mechanism ejects the blank, and the conveying mechanism moves the blank between the ejecting mechanism and the six dies.

2. A cold heading device for a profiled bolt according to claim 1, characterized in that: The main die cavity of the first die includes a die upper forming cavity for forming the upper segment of the first blank and a die lower forming cavity for forming the lower segment of the first blank, and a transition cavity with a large upper part and a small lower part is arranged between the die upper forming cavity and the die lower forming cavity.

3. A cold heading device for a profiled bolt according to claim 1, characterized in that: The main die cavity of the second die includes a die upper forming cavity for forming the upper segment of the second blank into an upper large and lower small circular platform and a die lower forming cavity for forming the rod part of the second blank, and the upper end of the lower punch of the second die extends into the die lower forming cavity.

4. A cold heading device for a profiled bolt according to claim 3, characterized in that: The upper die of the third die includes a die upper die core, and the lower end of the die upper die core is provided with a die top cavity for forming the upper end of the upper segment of the third blank into an upper small and lower large circular platform with a tapered top.

5. A cold heading device for a profiled bolt according to claim 3, characterized in that: The main die cavity of the third die includes, from bottom to top, a die lower forming cavity for forming the rod part of the third blank, a die octagonal forming cavity for forming the octagon of the third blank, and a die upper excess material cavity for accommodating the lower end of the head part of the third blank and the cut material of the octagon, and the minimum diameter of the die upper excess material cavity is greater than the maximum diameter of the die upper forming cavity. The upper end of the lower punch of the third die extends into the die lower forming cavity.

6. A cold heading device for a profiled bolt according to claim 1, characterized in that: The upper die of the four-die die set comprises a four-die upper cutting die core and an upper die punch rod, the four-die upper cutting die core comprises a four-die upper forming through hole for forming a hexagon by cutting a small upper large lower circular table of a third blank strip cone top, a conical cavity for protecting a fourth blank cone top is arranged at the lower end of the upper die punch rod, the lower end of the upper die punch rod extends into the four-die upper forming through hole, the main model cavity of the four-die die set comprises a lower accommodating cavity for accommodating a fourth blank rod part, a middle accommodating cavity for accommodating an octagon of the fourth blank and an upper end of the rod part, and a four-die upper forming cavity for forming a positioning step arranged in sequence from bottom to top, the diameter of the middle accommodating cavity is larger than the diameter of the three-die octagon forming cavity, and a forming gap for forming excess material is arranged between the upper die and the lower die of the four-die die set.

7. A cold heading device for a profiled bolt according to claim 6, characterized in that: The lower end inner cavity of the four-die upper forming through hole is arranged in a hexagonal column shape, the diameter of the upper end of the four-die upper forming through hole is arranged in a large upper small lower manner, and the diameter of the lower end of the upper die punch rod is smaller than the minimum diameter of the four-die upper forming through hole.

8. A cold heading device for a profiled bolt according to claim 6, characterized in that: The upper die of the cutting die set comprises an upper die shell and a cutting upper die core for cutting off excess material along the outer periphery of the positioning step to form a disc, the cutting upper die core is hollowly provided with a discharging through hole, the diameter of the discharging through hole is larger than the diameter of the four-die upper forming cavity, and the upper die shell is provided with a discharging channel matched with the discharging through hole.

9. A cold heading device for a profiled bolt according to claim 8, characterized in that: A sliding die core is arranged in the main model cavity of the cutting die set, the lower end of the sliding die core is arranged outside the main model cavity of the cutting die set and the outer periphery thereof is provided with an operating part, a first spring is arranged between the operating part and the lower die core of the cutting die set, an outer push rod for pushing the sliding die core to move is arranged below the sliding die core, the sliding die core is provided with an accommodating channel for accommodating an octagon and a rod part of a fifth blank, an active cavity for accommodating a second spring and an inner push rod is arranged in the outer push rod, the inner push rod comprises a push head arranged in the active cavity and a push rod part connected with the push head at one end and arranged in the accommodating channel at the other end, and the other end of the push head relative to the sliding die core is provided with the second spring.

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