Cold heading device for special-shaped sleeve

Abstract

The utility model relates to a cold heading device for a special-shaped sleeve. The cold heading device comprises a cutting mechanism, an ejection mechanism, a conveying mechanism and six dies. The conveying mechanism moves between the ejection mechanism and the six molds for feeding; the first upsetting die is used for chamfering the lower end of an initial blank; the second upsetting die is used for chamfering the upper end of a turned first blank and punching concave holes in two ends; the third upsetting die is used for stretching and forming a second blank turned again and deepening the depth of an inner hole in the upper end to be 1 / 3 of the height of the second blank; the four-upsetting die is used for stretching and forming a third blank again and deepening a lower end inner hole to be 2 / 3 of the height of the third blank, the through hole die is used for enabling an upper end inner hole and a lower end inner hole of a fourth blank to be communicated to form a through hole, and the final upsetting die is used for enabling the middle of a fifth blank to form a convex arc. By the adoption of the technical scheme, the mold manufacturing structure is simple in technological process and convenient to maintain; the die is long in service life and low in cost.

Description

Technical Field

[0001] The utility model belongs to the technical field of machinery, and in particular relates to a cold heading device for a special-shaped sleeve. Background Art

[0002] In the past, the manufacturing process of special-shaped sleeves was relatively simple and rough, and there were certain limitations in the selection and performance of materials. Early sleeves may not meet the increasing performance and safety requirements of automobiles in terms of strength, durability and precision. With the rapid development of the automotive industry, the requirements for special-shaped sleeves are constantly increasing. For example, there are stricter standards in terms of high strength, light weight, high precision and adaptability to complex working conditions. In terms of materials, traditional metal materials may gradually be replaced by alloy materials with better performance to improve the strength and wear resistance of the inner core.

[0003] The existing cold heading of anisotropic sleeves has the following problems: (1) Die wear: During the cold heading process, the die is subjected to high pressure and friction. Frequent metal flow will cause wear on the working surface of the die, especially when forming anisotropic sleeves with convex arcs. Due to uneven metal flow, some parts of the die will wear faster. This will not only affect the dimensional accuracy and surface quality of the sleeve, but also increase production costs because the mold needs to be replaced frequently. (2) Equipment stability: The cold heading process is a continuous high-speed forming process, and the stability of the equipment is crucial. Slight vibrations of the equipment or looseness of components may affect the forming quality of the sleeve, such as causing defects such as vibration marks on the sleeve surface. (3) Surface quality: After cold heading, the surface of the anisotropic sleeve may have some defects, such as folds and scratches. Folds are caused by unreasonable metal flow and the accumulation of some metal materials on the surface; scratches may be caused by reasons such as the mold surface is not smooth enough or impurities on the blank surface. Utility Model Content

[0004] In summary, in order to overcome the deficiencies of the prior art, the utility model provides a novel cold heading forming device for welding hexagonal flange nuts which saves cost and improves quality.

[0005] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a cold heading device for a special-shaped sleeve, comprising a cutting mechanism, an ejection mechanism, a conveying mechanism and six dies, wherein the cutting mechanism cuts the blank, and the ejection mechanism lifts the blank; the conveying mechanism moves and feeds between the ejection mechanism and the six dies; the six dies comprise: a first heading die for chamfering the lower end of the initial blank, a second heading die for chamfering the upper end of the flipped first blank and punching out recesses at both ends, a third heading die for stretching the flipped second blank again and deepening the inner hole of the upper end to 1 / 3 of the height of the second blank, and a third heading die for stretching the third blank again and deepening the lower end. Four upsetting dies with an inner hole depth of 2 / 3 of the height of the third blank, a through hole die for connecting the inner hole at the upper end of the fourth blank with the inner hole at the lower end to form a through hole, and a final upsetting die for forming a convex arc in the middle of the fifth blank; the six dies all include a lower die and an upper die, the lower die includes a lower die shell, a lower die core, a lower die punch, a lower die locking nut and a lower die ejector pad, the lower die core is arranged in the lower die shell, a main mold cavity is arranged in the lower die core, the lower die ejector pad is arranged below the lower die core, and the lower die locking nut fixes the lower die ejector pad and the lower die core by connecting with the lower die shell; the upper die includes an upper die shell, an upper die pad and an upper die punch, and the upper die pad is arranged in the upper die shell.

[0006] By adopting the above technical scheme, the convex arc part of the sleeve is completely formed. Compared with the traditional machining of the outer arc of the sleeve, it saves time and materials, so that the sleeve can achieve lightweight design while meeting the performance requirements. First of all, the length of the material is considered. When the metal is subjected to axial pressure, part of the material is squeezed to the central area, and the other part is evenly diffused to the inner wall to reach the required height, gradually stretched and gradually through-hole, and the large diameter material is stretched and contracted into a small diameter material and punched out of the inner hole, thereby improving production efficiency. The inner hole of large-size parts is formed by cold heading, so that the cold heading material is fully utilized, saving materials and reducing costs, reducing the use of machining, and achieving the effect of cold heading rapid forming parts without tear marks on the inner hole, efficient forming, high material utilization rate and excellent product quality. The convex arc is formed after the hole is through-hole. After the blank is punched, the internal stress distribution of the material is mainly concentrated around the hole. During subsequent forming, the metal flows and deforms around the hole, with higher precision, more reasonable metal flow and longer mold life.

[0007] The utility model is further configured as follows: the main mold cavity of the first upsetting mold includes a first lower molding cavity for chamfering the lower end of the initial blank; the main mold cavity of the second upsetting mold includes a second lower molding cavity for chamfering the upper end of the flipped first blank; the upper die punch of the second upsetting mold includes a first convex portion for punching the lower end of the first blank out of a concave hole; the lower die punch of the second upsetting mold includes a second convex portion for punching the upper end of the first blank out of a concave hole; the main mold cavity of the third upsetting mold is longer than the main mold cavity of the second upsetting mold, and a first push tube is arranged outside the upper die punch of the third upsetting mold; The upper die punch of the three-heading mold passes through the first push tube and extends into the main model cavity of the three-heading mold to deepen the inner hole at the upper end of the second blank; a spring positioning pad and a three-needle pad are arranged between the lower die core and the lower die pad of the four-heading mold, the main model cavity length of the four-heading mold is greater than the main model cavity of the three-heading mold, and a second push tube is arranged outside the upper die punch of the four-heading mold. The upper die punch of the four-heading mold passes through the second push tube and extends into the main model cavity of the four-heading mold. The depth is equal to the depth of the upper die punch of the three-heading mold passing through the first push tube and extending into the main model cavity of the three-heading mold. The lower die punch of the four-heading mold A third push tube is arranged outside, and the lower die punch of the four-upsetting mold passes through the third push tube and extends into the main model cavity of the four-upsetting mold to deepen the inner hole at the lower end of the third blank; the main model cavity of the through-hole mold has the same shape as the main model cavity of the four-upsetting mold, and the upper die punch of the through-hole mold is hollowly provided with a discharge channel, and the upper die pad of the through-hole mold is provided with a discharge groove connected with the discharge channel, and the lower die punch of the through-hole mold passes through the lower die pad of the through-hole mold and is pushed into the discharge channel; the upper mold shell of the final upsetting mold is provided with an upper die core, and the upper die core includes an upper die forming The mold cavity, the length of the main mold cavity of the final upsetting mold plus the upper mold forming cavity is less than the length of the main mold cavity of the through-hole mold, the upper mold forming cavity includes an upper molding cavity for compressing the upper end of the fifth blank and an upper molding cavity for shaping the upper convex arc in the middle of the fifth blank, the main mold cavity of the final upsetting mold includes a lower molding cavity for shaping the lower convex arc in the middle of the fifth blank and a lower molding cavity for compressing the lower end of the fifth blank, the upper mold punch of the final upsetting mold and the lower mold punch of the final upsetting mold are closed, and the main mold cavity of the final upsetting mold and the upper mold forming cavity are symmetrically arranged.

[0008] By adopting the above technical scheme, the first three sequences are flipped twice, so that both ends of the blank are chamfered, and the sleeve can be punched at different angles by flipping, so that the punching position is more accurate, avoiding the problem of uneven sleeve deformation caused by single-sided punching, and ensuring the quality and accuracy of punching; the three-upsetting die is provided with a first push tube to ensure the precise positioning of the upper die and the lower die during the stamping process, and at the same time can reduce the scratches and wear on the workpiece surface during the pushing process, so as to ensure that the inner hole is flat and free of tearing bands when impacted, thereby extending the service life of the die and reducing production costs; the four-upsetting die is provided with a spring positioning pad and a three-needle pad, which can effectively absorb part of the impact force and play a buffering role, and change the stroke of the punch by adjusting the compression amount of the spring, so as to achieve punching and forming of different depths. The molding process also improves the versatility and economy of the mold; the lower mold of the through-hole mold moves upward as a whole, so that the lower mold punch of the through-hole mold punches out a small amount of excess material in the inner hole of the part, and the inner hole of the part is punched out to retain a step to reduce the tear zone; in the final upsetting mold, the blank is squeezed and deformed in the concave mold cavity, and a convex arc is gradually formed according to the shape of the upper molding cavity and the lower molding cavity; in order to make the metal flow of the arc part more uniform, the surfaces of the upper molding cavity and the lower molding cavity need to be finely polished to reduce the metal flow resistance; the convex arc is formed in sections, and the structure is more reasonable and stable, ensuring that the convex arc part can be completely separated from the mold, and the molding quality is better. The two punches are closed to ensure that the blank is not concave inward, and the upper and lower push tubes make the blank convex and close to the mold, ensuring the size is qualified under effective pressure.

[0009] The utility model is further configured that: the lower die punch of the through-hole die is provided with a conical punch, and the cone angle of the conical punch is 30°.

[0010] By adopting the above technical solution, compared with the flat bottom design of the punch head that affects the metal flow, the tapered punch makes the wall thickness and other dimensions of the sleeve more in line with the requirements in the subsequent forming process, avoiding material accumulation and dimensional deviations, improving metal flow, and allowing the metal to be more evenly distributed around the punching area during cold heading, thereby ensuring the quality of the sleeve and reducing stress concentration and internal defects; the punch movement requires stability to prevent eccentricity caused by deviation. After penetration, the punch's dwell time of 3-5S and return speed must be controlled. Too short a dwell time may cause unstable through-hole shape, and too fast a return speed may cause scratches and other damage to the through-hole inner wall.

[0011] The utility model is further configured as follows: a transition fillet is provided at the connection between the upper shaping cavity and the upper forming cavity, and a transition fillet is provided at the connection between the lower shaping cavity and the lower forming cavity, and the radius of the transition fillet is 55%-65% of the radius of the upper shaping cavity.

[0012] By adopting the above technical solution, reasonable transition fillets are set at the turning points of the mold cavity. These transition fillets can guide the flow of metal materials and avoid stress concentration in the material during the molding process, thereby preventing defects such as cracks or folds. Reasonable transition fillet radius can make the metal flow more smoothly from the straight part to the arc part.

[0013] The utility model is further provided that: an annular limit is provided at one end of the discharge channel of the through-hole die relative to the lower die.

[0014] By adopting the above technical solution, the waste can be gradually confined to a specific shape space during the punching process. When the punching action is completed, the annular limiter can block and position the waste, preventing the waste from easily falling off the punch rod, thereby facilitating the collection and subsequent processing of the waste.

[0015] The embodiments describe the specific implementation of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the gradual cold upsetting of a blank according to an embodiment of the utility model.

[0017] Figure 2 It is a cross-sectional view of a cold heading device according to an embodiment of the utility model.

[0018] Figure 3 for Figure 2 Enlarged view of part A.

[0019] Figure 4 for Figure 2 Enlarged view of part B.

[0020] Figure 5 for Figure 2 Enlarged view of part C.

[0021] Figure 6 for Figure 2 Enlarged view of part D.

[0022] Figure numerals: 1. a forging die, 11. a lower die of a forging die, 111. a lower die shell of a forging die, 112. a main mold cavity of a forging die, 1121. a first lower molding cavity, 12. an upper die of a forging die, 121. an upper die shell of a forging die, 122. an upper die pad of a forging die; 2. a second forging die, 21. a lower die of a second forging die, 211. a lower die shell of a second forging die, 212. a main mold cavity of a second forging die, 2121. a second lower molding cavity, 213. a lower die punch of a second forging die, 2131. a second convex portion, 22. an upper die of a second forging die, 221. an upper die shell of a second forging die, 222 . The upper die punch of the second upsetting die, 2221. The first convex part; 3. The third upsetting die, 31. The lower die of the third upsetting die, 311. The lower die shell of the third upsetting die, 312. The main mold cavity of the third upsetting die, 313. The lower die punch of the third upsetting die, 32. The upper die of the third upsetting die, 321. The upper die shell of the third upsetting die, 322. The upper die pad of the third upsetting die, 323. The upper die punch of the third upsetting die, 324. The first push tube; 4. The fourth upsetting die, 41. The lower die of the fourth upsetting die, 411. The lower die shell of the fourth upsetting die, 412. The main mold cavity of the fourth upsetting die, 413. The lower die punch of the fourth upsetting die, 414. The third push tube , 415. lower die pad, 416. spring positioning pad, 417. three-needle pad, 42. upper die of four-upsetting die, 421. upper die shell of four-upsetting die, 422. upper die pad of four-upsetting die, 423. upper die punch of four-upsetting die, 424. second push tube; 5. through-hole die, 51. lower die of through-hole die, 511. lower die shell of through-hole die, 512. main mold cavity of through-hole die, 513. lower die pad of through-hole die, 514. lower die punch of through-hole die, 5141. conical punch, 52. upper die of through-hole die, 521. upper die shell of through-hole die, 522. upper Die pad, 5221. discharge groove, 523. upper die punch of through hole die, 5231. discharge channel, 5232. annular limiter; 6. final forging die, 61. lower die of final forging die, 611. lower die shell of final forging die, 612. main model cavity of final forging die, 6121. lower section shaping cavity, 6122. lower section forming cavity, 613. lower die punch of final forging die, 62. upper die of final forging die, 621. upper die shell of final forging die, 622. upper die forming cavity, 6221. upper section forming cavity, 6222. upper section shaping cavity, 6223. transition fillet, 623. upper die punch of final forging die. DETAILED DESCRIPTION

[0023] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

[0024] See attached Figure 1-6 The embodiment discloses a cold heading device for a special-shaped sleeve, comprising a cutting mechanism, an ejection mechanism, a conveying mechanism and six dies, wherein the cutting mechanism cuts off the blank, and the ejection mechanism lifts up the blank; the conveying mechanism moves and feeds between the ejection mechanism and the six dies; the six dies comprise: a first heading die 1 for chamfering the lower end of the initial blank, a second heading die 2 for chamfering the upper end of the flipped first blank and punching out recesses at both ends, a third heading die 3 for stretching the flipped second blank again and deepening the inner hole depth of the upper end to 1 / 3 of the height of the second blank, and a third heading die 4 for stretching the third blank again and deepening the inner hole depth of the lower end to a third A four-upsetting die 4 that is 2 / 3 of the height of the blank, a through-hole die 5 for connecting the inner hole at the upper end of the fourth blank with the inner hole at the lower end to form a through hole, and a final upsetting die 6 for forming a convex arc in the middle of the fifth blank; the six dies all include a lower die and an upper die, the lower die includes a lower die shell, a lower die core, a lower die punch, a lower die locking nut and a lower die ejector pad, the lower die core is arranged in the lower die shell, a main mold cavity is arranged in the lower die core, the lower die ejector pad is arranged below the lower die core, and the lower die locking nut is connected to the lower die shell to fix the lower die ejector pad and the lower die core; the upper die includes an upper die shell, an upper die pad and an upper die punch, and the upper die pad is arranged in the upper die shell.

[0025] The present embodiment is further configured as follows: the main mold cavity 112 of the first upsetting mold 1 includes a first lower molding cavity 1121 for chamfering the lower end of the initial blank; the main mold cavity 212 of the second upsetting mold 2 includes a second lower molding cavity 2121 for chamfering the upper end of the flipped first blank, the upper die punch 222 of the second upsetting mold 2 includes a first convex portion 2221 for punching the lower end of the first blank out of a recess, and the lower die punch 213 of the second upsetting mold 2 includes a second convex portion 2131 for punching the upper end of the first blank out of a recess; the main mold cavity 312 of the third upsetting mold 3 is longer than the main mold cavity 212 of the second upsetting mold 2, the upper die punch 323 of the third upsetting mold 3 is provided with a first push tube 324, and the upper die punch 222 of the third upsetting mold 3 includes a first convex portion 2221 for punching the lower end of the first blank out of a recess The rod 323 passes through the first push tube 324 and extends into the main model cavity 312 of the three-upsetting mold 3 to deepen the inner hole at the upper end of the second blank; a spring positioning pad 416 and a three-needle pad 417 are arranged between the lower die core and the lower die pad 415 of the four-upsetting mold 4, the main model cavity 412 of the four-upsetting mold 4 is longer than the main model cavity 312 of the three-upsetting mold 3, and a second push tube 424 is arranged outside the upper die punch 423 of the four-upsetting mold 4, and the upper die punch 423 of the four-upsetting mold 4 passes through the second push tube 424 and extends into the main model cavity 412 of the four-upsetting mold 4. The depth is equal to the depth of the upper die punch 323 of the three-upsetting mold 3 passing through the first push tube 324 and extending into the main model cavity 312 of the three-upsetting mold 3, and the lower die punch 413 of the four-upsetting mold 4 is arranged outside. A third push tube 414 is provided, and the lower die punch 413 of the four-heading mold 4 passes through the third push tube 414 and extends into the main model cavity 412 of the four-heading mold 4 to deepen the inner hole at the lower end of the third blank; the main model cavity shape 512 of the through-hole mold 5 is the same as the main model cavity 412 of the four-heading mold 4, and the upper die punch 523 of the through-hole mold 5 is hollowly provided with a discharge channel 5231, and the upper die pad 522 of the through-hole mold 5 is provided with a discharge groove 5221 connected with the discharge channel 5231, and the lower die punch 514 of the through-hole mold 5 passes through the lower die pad 513 of the through-hole mold 5 and is pushed up to the discharge channel 5231; the upper mold shell 621 of the final heading mold 6 is provided with an upper mold core, and the upper mold core includes a The upper die forming cavity 622, the length of the main model cavity 612 of the final upsetting die 6 plus the upper die forming cavity 622 is less than the length of the main model cavity 512 of the through hole die 5, the upper die forming cavity 622 includes an upper section forming cavity 6221 for compressing the upper end of the fifth blank and an upper section shaping cavity 6222 for shaping the upper convex arc in the middle of the fifth blank, the main model cavity 612 of the final upsetting die 6 includes a lower section shaping cavity 6121 for shaping the lower convex arc in the middle of the fifth blank and a lower section shaping cavity 6122 for compressing the lower end of the fifth blank, the upper die punch 623 of the final upsetting die 6 is closed with the lower die punch 613 of the final upsetting die 6, and the main model cavity 612 of the final upsetting die 6 and the upper die forming cavity 622 are symmetrically arranged.

[0026] This embodiment further provides that: the lower die punch 514 of the through-hole die 5 is provided with a conical punch 5141, and the cone angle of the conical punch 5141 is 30°.

[0027] This embodiment is further configured as follows: a transition fillet 6223 is provided at the connection between the upper shaping cavity 6221 and the upper forming cavity 6222, and a transition fillet 6223 is provided at the connection between the lower shaping cavity 6121 and the lower forming cavity 6122, and the radius of the transition fillet 6223 is 55%-65% of the radius of the upper shaping cavity 6222.

[0028] This embodiment further provides that: an annular limit 5232 is provided at one end of the discharge channel 5231 of the through-hole mold 5 opposite to the lower mold.

[0029] The above-mentioned "between" does not only refer to directions and positions, but also includes the interaction between different parts. The above-mentioned "upper", "middle" and "lower" are only relative positions for the convenience of explanation, and does not exclude the possibility of using other terms.

[0030] These terms are used only to more conveniently describe and explain the essence of the present invention; any additional limitations interpreted as these terms are contrary to the spirit of the present invention.

Claims

1. A cold heading device for a special-shaped sleeve, characterized in that: The invention comprises a cutting mechanism, an ejection mechanism, a conveying mechanism and six moulds, wherein the cutting mechanism cuts the blank, and the ejection mechanism lifts the blank; the conveying mechanism moves and feeds between the ejection mechanism and the six moulds; the six moulds comprise: a first upsetting mould for chamfering the lower end of the initial blank, a second upsetting mould for chamfering the upper end of the flipped first blank and punching out recesses at both ends, a third upsetting mould for stretching the flipped second blank again and deepening the inner hole depth of the upper end to 1 / 3 of the height of the second blank, a fourth upsetting mould for stretching the third blank again and deepening the inner hole depth of the lower end to 2 / 3 of the height of the third blank A upsetting die, a through hole die for forming a through hole by connecting the inner hole at the upper end and the inner hole at the lower end of the fourth blank, and a final upsetting die for forming a convex arc in the middle part of the fifth blank; the six dies all include a lower die and an upper die, the lower die includes a lower die shell, a lower die core, a lower die punch, a lower die locking nut and a lower die ejector pad, the lower die core is arranged in the lower die shell, a main mold cavity is arranged in the lower die core, the lower die ejector pad is arranged below the lower die core, and the lower die locking nut fixes the lower die ejector pad and the lower die core by connecting with the lower die shell; the upper die includes an upper die shell, an upper die pad and an upper die punch, and the upper die pad is arranged in the upper die shell.

2. The cold heading device for a special-shaped sleeve according to claim 1, characterized in that: The main mold cavity of the first upsetting mold includes a first lower molding cavity for chamfering the lower end of the initial blank; the main mold cavity of the second upsetting mold includes a second lower molding cavity for chamfering the upper end of the flipped first blank, the upper die punch of the second upsetting mold includes a first convex portion for punching the lower end of the first blank out of the concave cavity, and the lower die punch of the second upsetting mold includes a second convex portion for punching the upper end of the first blank out of the concave cavity; the main mold cavity of the third upsetting mold is longer than the main mold cavity of the second upsetting mold, the upper die punch of the third upsetting mold is provided with a first push tube, and the upper die punch of the third upsetting mold The first push tube is inserted into the main model cavity of the three-upsetting mold to deepen the inner hole at the upper end of the second blank; a spring positioning pad and a three-needle pad are arranged between the lower die core and the lower die pad of the four-upsetting mold, the main model cavity length of the four-upsetting mold is greater than the main model cavity of the three-upsetting mold, and a second push tube is arranged outside the upper die punch of the four-upsetting mold. The upper die punch of the four-upsetting mold passes through the second push tube and extends into the main model cavity of the four-upsetting mold to a depth equal to the depth of the upper die punch of the three-upsetting mold passing through the first push tube and extending into the main model cavity of the three-upsetting mold. A third push tube is arranged outside the lower die punch of the four-upsetting mold. The push tube, the lower die punch of the four-heading die passes through the third push tube and extends into the main mold cavity of the four-heading die to deepen the inner hole at the lower end of the third blank; the main mold cavity of the through-hole die has the same shape as the main mold cavity of the four-heading die, the upper die punch of the through-hole die is hollowly provided with a discharge channel, the upper die pad of the through-hole die is provided with a discharge groove connected to the discharge channel, and the lower die punch of the through-hole die passes through the lower die pad of the through-hole die and is pushed into the discharge channel; the upper die shell of the final upsetting die is provided with an upper die core, and the upper die core includes an upper die forming cavity for forming the upper section of the fifth blank, The length of the main model cavity of the final upsetting mold plus the upper mold forming cavity is less than the length of the main model cavity of the through-hole mold. The upper mold forming cavity includes an upper molding cavity for compressing the upper end of the fifth blank and an upper molding cavity for shaping the upper convex arc in the middle of the fifth blank. The main model cavity of the final upsetting mold includes a lower molding cavity for shaping the lower convex arc in the middle of the fifth blank and a lower molding cavity for compressing the lower end of the fifth blank. The upper mold punch of the final upsetting mold and the lower mold punch of the final upsetting mold are closed, and the main model cavity of the final upsetting mold and the upper mold forming cavity are symmetrically arranged.

3. The cold heading device for a special-shaped sleeve according to claim 2, characterized in that: The lower die punch of the through-hole die is provided with a conical punch, and the cone angle of the conical punch is 30°.

4. The cold heading device for a special-shaped sleeve according to claim 2, characterized in that: A transition fillet is provided at the connection between the upper shaping cavity and the upper forming cavity, and a transition fillet is provided at the connection between the lower shaping cavity and the lower forming cavity, and the radius of the transition fillet is 55%-65% of the radius of the upper shaping cavity.

5. The cold heading device for a special-shaped sleeve according to claim 2, characterized in that: An annular limiter is provided at one end of the discharge channel of the through-hole mold relative to the lower mold.

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