One-step forming process of hexagon socket round tail bolt and bolt forming die used therefor
Through the one-time molding process of the hexagonal round tail bolt and the specific mold design, the problem of forming traditional hexagonal round tail bolts is solved, efficient and stable production is achieved, cost reduction and quality improvement, and mold maintenance is simplified.
Patent Information
- Application Number
- CN202010500476.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2020-06-04
- Publication Date
- 2025-08-26
- Estimated Expiration
- 2040-06-04
AI Technical Summary
During the molding of traditional hexagonal round tail bolts, the arc size of the tail is difficult to form at one time, resulting in waste of materials, high machining costs, and low production efficiency, which is prone to defective products, especially in large-scale production, which is difficult to select and high cost.
The hexagonal round tail bolt is adopted to form a one-time molding process. Through four steps: cutting, chamfering, round tail forming, bolt head preforming and final forming, a specific design of bolt forming mold, including moving die, fixed die, multiple molds and starter rods, the wire diameter and mold inner hole design are controlled to reduce the length of the material through rod, reduce impact force, avoid exhaust holes, and ensure that the arc is full and smooth.
It realizes efficient and stable production of bolts, reduces production costs, improves finished product quality and output, reduces defective yield, simplifies mold replacement and maintenance, and reduces production difficulty.
Smart Images
Figure CN111590008B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of screw processing, in particular to a one-step forming process for a hexagon socket round tail bolt and a bolt forming die used therefor. Background Art
[0002] Traditional hexagon socket round tail bolts are difficult to get the tail arc size right in one go because the head is formed to punch the wrench hole and the tail arc is subjected to great force. They are usually punched out in three dies and then machined, which wastes materials, has high machining costs, occupies turnover space, and wastes manpower and material resources. Even if it is improved and designed into four-die four-in-one arc forming, according to conventional cutting, the end face is flat, and according to the fluidity of the metal material, if there is no special treatment, the periphery will be high, the middle will be low, and the end face will be concave when it is pulled out of one die. The arc formed later will not be smooth and full or there will be small steps, and the size will not be in place. The feeding rod is the same length as the main mold. The feeding rod is placed in the arc to pierce the exhaust hole, and the force is large. The arc is easy to crack. Generally, thousands or hundreds of them will crack, and the cost is high. In continuous production, it is easy to produce defective products, and selection is difficult. In large-scale production, it is very laborious for production personnel to switch. The hexagon socket arc bolt is mainly formed by the through rod at the tail arc, but because the through rod has an arc and vents, it is easy to crack, and the cost of scrapping the entire rod is very high. Summary of the Invention
[0003] In order to overcome the above-mentioned defects, the present invention provides a one-step forming process for hexagon socket round tail bolts and a bolt forming mold used therefor. The bolts produced by the one-step forming process for hexagon socket round tail bolts and the bolt forming mold used therefor have stable quality, improve production efficiency and reduce production costs.
[0004] The technical solution adopted by the present invention to solve the technical problem is: a one-step forming process for hexagon socket round head bolts, the specific steps are as follows:
[0005] Step 1: Cutting
[0006] The wire is cut into a cut piece, and a cut surface at one end of the cut piece is formed into an inclined surface;
[0007] Step 2: Chamfer
[0008] Feed the cut material into the first die and chamfer the beveled end;
[0009] Step 3: Round tail shaping
[0010] The chamfered cut material is fed into the second die, and the other end of the cut material is rounded;
[0011] Step 4: Pre-forming the bolt head
[0012] The cut material is fed into the third die, and the chamfered end of the cut material is upset to initially form the bolt head;
[0013] Step 5: Bolt blank forming:
[0014] The cut material is fed into the fourth die to finalize the shape of the bolt head and the hexagonal groove on the end face.
[0015] As a further improvement of the present invention, in step one, the wire is first designed so that the wire diameter is 0.3-0.35 mm smaller than the finished wire diameter, and in step two, the chamfered inner hole diameter of the first die of the fixed die matches the outer diameter of the finished product.
[0016] As a further improvement of the present invention, the first punch on the first punch of the movable die drives all the cut materials into the first die inner hole of the fixed die.
[0017] A bolt forming die comprises a movable die, a fixed die, a first die, a second die, a third die, a fourth die, a first punch, a second punch, a third punch, a fourth punch, a first feeding rod, a second feeding rod, a third feeding rod, a fourth feeding rod, a first starting rod, a second starting rod, a third starting rod and a fourth starting rod, wherein the first die, the second die, the third die and the fourth die are respectively fixedly mounted on the fixed die, and the first punch, the second punch, the third punch and the fourth punch are respectively fixedly mounted on the movable die, and the first punch, the second punch, the third punch and the fourth punch are respectively arranged opposite to one end of the first die, the second die, the third die and the fourth ... The first punch, the second punch, the third punch and the fourth punch are respectively provided with a first punch, a second punch, a third punch and a fourth punch which can impact one end of the cut material. The first punch, the second punch, the third punch and the fourth punch are respectively matched with the shape to be formed at one end of each cut material. A chamfered inner hole with a diameter at one end larger than that at the other end is formed in the first die. The two ends of the chamfered inner hole are transitionally connected by a chamfered inclined surface. One end of the first feeding rod can be slidably inserted into the end with a smaller diameter of the chamfered inner hole. A stepped inner die hole with a diameter at one end smaller than that at the other end is formed in the second die, the third die and the fourth die. One end of the rod, the third feeding rod and the fourth feeding rod are respectively and one-to-one correspondingly slidably inserted into the end with the smaller diameter of the stepped inner die hole of the second die, the third die and the fourth die, and the head with the expanded diameter on the other end of the second feeding rod, the third feeding rod and the fourth feeding rod is stopped on the step surface formed between the two ends of the stepped inner die hole, one end of the first feeding rod is an inclined surface, and one end of the second feeding rod, the third feeding rod and the fourth feeding rod is an inwardly concave spherical surface, and the second starting rod, the third starting rod and the fourth starting rod are respectively slidably inserted into the end with the larger diameter of the stepped inner die hole of the second die, the third die and the fourth die. , and the first starting rod, the second starting rod, the third starting rod and the fourth starting rod can respectively press against the other end of the first feeding rod, the second feeding rod, the third feeding rod and the fourth feeding rod and drive them to slide axially to push the material. The third mold and the fourth mold are also respectively provided with a bolt head preforming sheet mold and a bolt head forming sheet mold towards the end of the movable mold. A preformed inner hole is formed in the bolt head preforming sheet mold, which is connected to the stepped inner mold hole of the third mold and matches the preformed outer shape of the bolt head. A forming inner hole is formed in the bolt head forming sheet mold, which is connected to the stepped inner mold hole of the fourth mold and matches the final outer shape of the bolt head.
[0018] As a further improvement of the present invention, the second mold, the third mold and the fourth mold are respectively fixed with an inner mold front mold core and an inner mold rear mold core which can be detachably provided. A countersunk hole with a diameter at one end smaller than the diameter at the other end is formed in the inner mold front mold core. The second feeding rod, the third feeding rod and the fourth feeding rod are respectively inserted into the countersunk holes of the second mold, the third mold and the fourth mold, and the heads with expanded diameters on the other ends of the second feeding rod, the third feeding rod and the fourth feeding rod can just be accommodated in the countersunk heads of the countersunk holes. A straight hole for inserting the starting rod is provided in the inner mold rear mold core, and the straight hole is coaxial with the countersunk hole of the inner mold front mold core.
[0019] As a further improvement of the present invention, the inner diameter of the straight hole in the rear mold core of the inner mold is consistent with the inner diameter of the countersunk hole in the front mold core of the inner mold.
[0020] As a further improvement of the present invention, the second and third material rods are also provided with material rod exhaust holes for allowing one end of the material rod to pass through the interior of the material rod to the outer circumferential wall of the material rod. The third and fourth mold side walls are also provided with inner mold exhaust holes for connecting the outer wall of the inner mold front mold core with the outside world.
[0021] As a further improvement of the present invention, three-section two-step holes with diameters gradually expanding from one end to the other are formed in the second mold, the third mold and the fourth mold respectively. The front mold core of the inner mold and the rear mold core of the inner mold are inserted into the second step hole. One end of the front mold core of the inner mold is tightly against the step surface between the first step hole and the second step hole. A rear lock is also provided. The rear lock can be removably fixed in the third step hole, and the other end of the rear mold core of the inner mold is tightly against the surface of one end of the rear lock.
[0022] As a further improvement of the present invention, the inner mold rear mold core is a T-shaped structure with an outer diameter at one end larger than the outer diameter at the other end. The rear lock is threadedly connected to the third section of the step hole. A through hole is formed in the rear lock for inserting the other end of the inner mold rear mold core. One end of the rear lock is tightly against the step surface between the two ends of the inner mold rear mold core.
[0023] As a further improvement of the present invention, the punch on the first punch can be inserted into the inner hole of the first die, the punch on the second punch is formed with a funnel-shaped groove with a diameter at one end smaller than the diameter at the other end, the punch on the third punch is formed with a chamfered groove with low sides and high middle, and the punch on the fourth punch is formed with a raised hexagonal column in the middle.
[0024] The beneficial effects of the present invention are as follows: the present invention selects wire materials with a smaller diameter than the finished wire material for cutting and forming, and controls the position of the cutter during cutting so that one end of the cut material forms an inclined surface, and uses the punch of the first punch to punch all the cut material into the first die. When the first die forces the bundle angle, the uneven end material flows faster, and the cut material in the first die will not be concave. The present invention designs the second, third, and fourth dies into the form of a front core and a rear core of the inner die, and the second, third, and fourth through-material rods are inserted into the front die core of the inner die. A series of standard bolts can be formed by the through-material rods, and the inner hole of the rear core is enlarged and made to be the same size as the starting rod of the machine. In this way, the length of the through-material rod is greatly shortened, and the enlarged starting rod greatly reduces the impact force and thrust of the through-material rod. In addition to the small tail of the cut material and the first die bundle, the cut material is quickly filled with the arc in the second and third dies, and the arc is very full. In this way, there is no need to release the exhaust hole on the through-material rod of the fourth die, and the arc is also full and smooth, which greatly relieves the pressure of the fourth die punching the wrench hole and forming the arc, and the output of the bolts is greatly improved, and the quality is stable. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 This is a front view of the cut material formed by cutting the wire in the prior art;
[0026] Figure 2 This is a structural diagram of a bolt forming die in the prior art;
[0027] Figure 3 This is a structural diagram of the bolt forming die of the present invention;
[0028] Figure 4 for Figure 3 Enlarged view of part A in the middle;
[0029] Figure 5 This is a schematic diagram of the cutting material forming process of the present invention;
[0030] Figure 6 for Figure 5 Enlarged view of part B in the middle. DETAILED DESCRIPTION
[0031] Example: A one-step forming process for a hexagon socket round head bolt, the specific steps are as follows:
[0032] Step 1: Cutting
[0033] The wire rod is cut to form a cut piece 30 , and a cut surface at one end of the cut piece 30 forms an inclined surface 31 ;
[0034] Step 2: Chamfer
[0035] Feed the cut material 30 into the first die 1 and chamfer the end with the bevel 31;
[0036] Step 3: Round tail shaping
[0037] The chamfered cut piece 30 is fed into the second die 2, and the other end of the cut piece 30 is rounded;
[0038] Step 4: Pre-forming the bolt head
[0039] The cut material 30 is fed into the third die 3, and the chamfered end of the cut material 30 is upset to preliminarily form the bolt head;
[0040] Step 5: Bolt blank forming:
[0041] The cut material 30 is fed into the fourth die 4 to perform final shaping on the bolt head shape and the end face hexagonal groove.
[0042] When cutting wire, the cutter and die should break the traditional idea of cutting the material very flatly by keeping the cutter and die close to each other. Instead, the cutter and die should be kept farther apart intentionally. The end face of the cut material has an uneven bevel 31. Since the chamfer of the first die plays a vital role in the subsequent arc forming and thread rolling without flanging, the cut surface 30 of the cut material is uneven. In this way, when the first die 1 forces the beam angle, the uneven end material flows faster, the first die 1 material will not sink, and the second die 2 and the third die 3 will quickly fill the top of the round tail, making the arc full and smooth.
[0043] In step one, the wire is designed so that the wire diameter is 0.3-0.35 mm smaller than the finished wire diameter. In step two, the chamfered inner hole diameter of the first die 1 of the fixed die matches the outer diameter of the finished product.
[0044] The first punch on the first punch 5 of the movable die drives all the cut-off material 30 into the inner hole of the first die 1 of the fixed die.
[0045] The wire diameter is reduced, and a die is used to force the bundle, so the force required to draw a small tail is high. After repeated tests, the wire diameter of the finished product is reduced by 0.3mm. The inner hole of the first die 1 matches the finished product. There will be a certain gap between the inner hole of the first die 1 and the cut material 30. Use the punch of the first punch 5 to punch all the cut material 30 into the first die 1. This makes it easier to draw a small tail. The wire diameter is reduced and the cut surface of the cut material 30 is uneven. In this way, the uneven end material flows faster when the die is forced to bend, and the material of the first die 1 will not sink. The second die 2 and the third die 3 fill the top of the round tail faster, and the arc is fuller and smoother.
[0046] A bolt forming mold includes a movable mold, a fixed mold, a first mold 1, a second mold 2, a third mold 3, a fourth mold 4, a first punch 5, a second punch 6, a third punch 7, a fourth punch 8, a first feeding rod 9, a second feeding rod 10, a third feeding rod 11, a fourth feeding rod 12, a first starting rod, a second starting rod 13, a third starting rod 14 and a fourth starting rod 15, wherein the first mold 1, the second mold 2, the third mold 3 and the fourth mold 4 are respectively fixedly mounted on the fixed mold, and the first punch 5, the second punch 6, the third punch 7 and the fourth punch 8 are respectively fixedly mounted on the movable mold, and the first punch 5, the second punch 6, the third punch 7 and the fourth punch 8 are respectively aligned with one end of the first mold 1, the second mold 2, the third mold 3 and the fourth mold 4. The first punch 5, the second punch 6, the third punch 7 and the fourth punch 8 are respectively provided with a first punch 16, a second punch 17, a third punch 18 and a fourth punch 19 which can impact one end of the cut material 30. The first punch 16, the second punch 17, the third punch 18 and the fourth punch 19 respectively match the shape to be formed at one end of each cut material 30. A chamfered inner hole 20 with a diameter at one end larger than that at the other end is formed in the first die 1. The two ends of the chamfered inner hole 20 are transitionally connected by a chamfered inclined surface 31. One end of the first feeding rod 9 can be slidably inserted into the end with a smaller diameter of the chamfered inner hole 20. A step-shaped shape with a diameter at one end smaller than that at the other end is formed in the second die 2, the third die 3 and the fourth die 4. Inner die hole, one end of the second feeding rod 10, the third feeding rod 11 and the fourth feeding rod 12 are respectively and one-to-one correspondingly slidably inserted into the end with the smaller diameter of the stepped inner die hole of the second die 2, the third die 3 and the fourth die 4, and the head with the expanded diameter on the other end of the second feeding rod 10, the third feeding rod 11 and the fourth feeding rod 12 is stopped on the step surface formed between the two ends of the stepped inner die hole, one end of the first feeding rod 9 is a slope 31, and one end of the second feeding rod 10, the third feeding rod 11 and the fourth feeding rod 12 is a concave spherical surface, and the second starting rod 13, the third starting rod 14 and the fourth starting rod 15 are respectively slidably inserted into the stepped inner die of the second die 2, the third die 3 and the fourth die 4. The end with the larger hole diameter is provided with a first starting rod, a second starting rod 13, a third starting rod 14 and a fourth starting rod 15, respectively, which can be tightly pressed against the other end of the first feeding rod 9, the second feeding rod 10, the third feeding rod 11 and the fourth feeding rod 12 and drive them to slide axially to push the material. The third mold 3 and the fourth mold 4 are also respectively provided with a bolt head pre-forming sheet mold 21 and a bolt head forming sheet mold 22 toward the end of the movable mold. A pre-formed inner hole is formed in the bolt head pre-forming sheet mold 21, which is connected with the stepped inner mold hole of the third mold 3 and matches the pre-formed outer shape of the bolt head. A forming inner hole is formed in the bolt head forming sheet mold 22, which is connected with the stepped inner mold hole of the fourth mold 4 and matches the final outer shape of the bolt head.The inner die holes of the second die 2, the third die 3 and the fourth die 4 are designed to be stepped holes, and the starting rod of the machine is inserted into the end with a larger diameter of the stepped hole. In this way, the length of the feeding rod is greatly shortened, and the enlarged starting rod greatly reduces the impact force and thrust of the feeding rod. In addition, the cut-off material 30 and the small tail of the first die 1 are added, and the cut-off material 30 is quickly filled with the arc in the second and third dies, and the arc is very full. In this way, the feeding rod of the fourth die 4 does not need to have an exhaust hole at all, and the arc is also full and smooth, which greatly relieves the pressure of the fourth die 4 on punching the wrench hole and forming the arc. The output of bolts has been greatly improved, and the quality is stable.
[0047] The second mold 2, the third mold 3 and the fourth mold 4 are respectively fixed with an inner mold front mold core 23 and an inner mold rear mold core 24 which can be detachably provided. A countersunk hole 25 with a diameter at one end smaller than the diameter at the other end is formed in the inner mold front mold core 23. The second feeding rod 10, the third feeding rod 11 and the fourth feeding rod 12 are respectively inserted into the countersunk holes 25 of the second mold 2, the third mold 3 and the fourth mold 4, and the heads with expanded diameters at the other ends of the second feeding rod 10, the third feeding rod 11 and the fourth feeding rod 12 can just be accommodated in the countersunk heads of the countersunk holes 25. A straight hole for inserting the starting rod is provided in the inner mold rear mold core 24, and the straight hole is coaxial with the countersunk hole 25 of the inner mold front mold core 23. The present invention makes the second, third and fourth molds into the form of an inner mold front mold core 23 and an inner mold rear mold core 24. A feeding rod is inserted into the inner mold front mold core 23, and a series of standard bolts can be formed through the feeding rod. The inner hole of the inner mold rear mold core 24 is enlarged and made to be the same size as the machine starting rod. In this way, the length of the feeding rod is greatly shortened, and the enlarged starting rod greatly reduces the impact force and thrust of the feeding rod. In addition, the cut-off material 30 and the small tail bundled by the first mold 1 are combined. The cut-off material 30 is quickly filled with the arc in the second and third molds, and the arc is very full. In this way, the fourth mold 4 does not need to have an exhaust hole for the feeding rod, and the arc is also full and smooth, which greatly relieves the pressure of the fourth mold 4 on punching the wrench hole and forming the arc. The output of bolts is greatly improved with stable quality.
[0048] The inner diameter of the straight hole in the inner mold rear mold core 24 is consistent with the inner diameter of the countersunk hole 25 in the inner mold front mold core 23.
[0049] The second and third die rods are also equipped with die vent holes 27, which allow one end of the die rod to pass through the die rod's interior to the outer wall of the die rod's circumference. The third and fourth die rods are also equipped with inner die vent holes 28 on their side walls, connecting the outer wall of the inner die front core 23 to the outside world. The die vent holes 27 are used to exhaust gas generated during the formation of the bolt round tail, while the inner die vent holes 28 of the fourth die 4 are used to exhaust gas generated during the formation of the bolt head.
[0050] The second, third, and fourth dies 2, 3, and 4 are each formed with a three-stage, two-stepped hole whose diameter gradually expands from one end to the other. The inner mold front core 23 and the inner mold rear core 24 are inserted into the second-stage stepped hole. One end of the inner mold front core abuts against the stepped surface between the first and second stages of the stepped hole. A rear lock 29 is also provided. The rear lock 29 is removably fixedly mounted in the third stage of the stepped hole. The other end of the inner mold rear core 24 abuts against the surface of one end of the rear lock 29. By designing the inner holes of the second, third, and fourth dies as three-stage, two-stepped holes and designing the inner mold as a split structure composed of the inner mold front core 23 and the inner mold rear core 24, the convenience of processing and installation of the inner mold is improved, the difficulty of manufacturing and assembly is reduced, and the production cost is reduced. At the same time, the inner mold front core 23 or the inner mold rear core 24 can be quickly disassembled and replaced when the bolt type is changed or when the inner mold front core 23 or the inner mold rear core 24 is worn, thereby improving the versatility of the mold and further reducing production cost.
[0051] The inner mold rear mold core 24 is a T-shaped structure with an outer diameter at one end larger than the outer diameter at the other end. The rear lock 29 is threadedly connected to the third section step hole. A through hole is formed in the rear lock 29 for inserting the other end of the inner mold rear mold core 24. One end of the rear lock 29 is tightly against the step surface between the two ends of the inner mold rear mold core 24.
[0052] The punch on the first punch 5 can be inserted into the inner hole of the first die 1. The punch of the second punch 6 is formed with a funnel-shaped groove with a smaller diameter at one end than at the other end. The punch of the third punch 7 is formed with a chamfered groove with lower edges and higher center. The punch of the fourth punch 8 is formed with a raised hexagonal protrusion 26 in the center. The punch of the first punch 5 is inserted into the first die 1 to drive the cut material 30 into the first die 1, to form a bevel and a small tail. The punch of the second punch 6 realizes the impact forming of the bolt tail while forming a funnel-shaped structure on the bolt head. The punch of the third punch 7 upsets the bolt head and forms the chamfered edge and the center groove. The fourth punch 8 continues to upset the bolt head into place and forms the flower teeth, while forming a hexagonal wrench slot in the center of the bolt head.
Claims
1. A one-step forming process for hexagon socket head bolts, characterized by: The specific steps are as follows: Step 1: Cutting The cutting knife and the cutting die are moved further away to cut the wire material to form a cut piece (30), and a cut surface at one end of the cut piece forms an inclined surface (31); Step 2: Chamfer Feed the cut material into the first die, chamfer the beveled end, and when the first die forces the bevel, the uneven end will flow faster, and the material in the first die will not sag. Step 3: Round tail shaping The chamfered cut material is fed into the second die, and the other end of the cut material is rounded; Step 4: Pre-forming the bolt head The cut material is fed into the third die, and the chamfered end of the cut material is upset to initially form the bolt head; Step 5: Bolt blank forming: The cut material is fed into the fourth die to finalize the bolt head shape and the hexagonal groove on the end face; The bolt forming mold used includes a movable mold and a fixed mold.
2. The one-step forming process for hexagon socket head bolts according to claim 1, characterized in that: In step one, the wire is designed so that the wire diameter is 0.3-0.35 mm smaller than the finished wire diameter. In step two, the inner hole diameter of the first die of the fixed die matches the outer diameter of the finished product.
3. The one-step forming process for hexagon socket head bolts according to claim 1 or 2, characterized in that: The punch on the first punch of the movable die drives all the cut materials into the first die inner hole of the fixed die.
4. A bolt forming mold used in the one-step forming process of the hexagon socket round tail bolt according to claim 1, comprising a movable mold, a fixed mold, a first mold (1), a second mold (2), a third mold (3), a fourth mold (4), a first punch (5), a second punch (6), a third punch (7), a fourth punch (8), a first feed rod (9), a second feed rod (10), a third feed rod (11), a fourth feed rod (12), a first starting rod, a second starting rod (13), a third starting rod (14) and a fourth starting rod (15), wherein the first mold, the second mold, the third mold and the fourth punch are connected. The four dies are fixedly mounted on the fixed die, respectively; the first punch, the second punch, the third punch and the fourth punch are fixedly mounted on the movable die, respectively; and the first punch, the second punch, the third punch and the fourth punch are respectively arranged opposite to one end of the first die, the second die, the third die and the fourth die, respectively; the first punch, the second punch, the third punch and the fourth punch are respectively provided with a first punch (16), a second punch (17), a third punch (18) and a fourth punch (19) capable of impacting one end of the cut material; the first punch, the second punch, the third punch and the fourth punch are respectively matched with the shape to be formed at one end of each cut material, and are characterized in that: A chamfered inner hole (20) having a diameter at one end larger than that at the other end is formed in the first die, and the two ends of the chamfered inner hole are connected by a chamfered inclined surface transition, and one end of the first feeding rod can be slidably inserted into the end with a smaller diameter of the chamfered inner hole, and a stepped inner die hole having a diameter at one end smaller than that at the other end is formed in the second die, the third die, and the fourth die, respectively. One end of the second feeding rod, the third feeding rod, and the fourth feeding rod can be slidably inserted into the end with a smaller diameter of the stepped inner die hole of the second die, the third die, and the fourth die, respectively, in a one-to-one correspondence. The head with an outwardly expanded diameter on the other end stops on the step surface formed between the two ends of the stepped inner die hole, one end of the first feeding rod is an inclined surface, and one end of the second feeding rod, the third feeding rod and the fourth feeding rod is an inwardly concave spherical surface, the second starting rod, the third starting rod and the fourth starting rod can be slidably inserted into the end with a larger diameter of the stepped inner die hole of the second die, the third die and the fourth die respectively, and the first starting rod, the second starting rod, the third starting rod and the fourth starting rod can respectively press against the other ends of the first feeding rod, the second feeding rod, the third feeding rod and the fourth feeding rod and drive them to slide axially to push the material. The third mold and the fourth mold are respectively provided with a bolt head preforming sheet mold (21) and a bolt head forming sheet mold (22) at one end facing the movable mold. A preformed inner hole that is connected to the stepped inner mold hole of the third mold and matches the preformed outer shape of the bolt head is formed in the bolt head preforming sheet mold. A forming inner hole that is connected to the stepped inner mold hole of the fourth mold and matches the final outer shape of the bolt head is formed in the bolt head forming sheet mold. The second mold, the third mold and the fourth mold are respectively fixed with an inner mold front mold core (23) and an inner mold rear mold core (24) that can be detachably fixed. The inner mold front mold core A countersunk hole (25) with a diameter at one end smaller than that at the other end is formed therein, and the second feeding rod, the third feeding rod and the fourth feeding rod are respectively inserted into the countersunk holes of the second die, the third die and the fourth die, and the heads with expanded diameters at the other ends of the second feeding rod, the third feeding rod and the fourth feeding rod can just be accommodated in the countersunk heads of the countersunk holes. A straight hole for inserting a starting rod is provided in the rear die core of the inner die, and the straight hole is coaxially aligned with the countersunk hole of the front die core of the inner die. The straight hole is the same size as the starting rod of the machine, and the length of the feeding rod is shortened. The enlarged starting rod greatly reduces the impact force and thrust of the feeding rod.
5. The bolt forming die according to claim 4, characterized in that: The inner diameter of the straight hole in the rear mold core of the inner mold is consistent with the inner diameter of the countersunk hole in the front mold core of the inner mold.
6. The bolt forming die according to claim 5, characterized in that: The second and third rods are also provided with rod exhaust holes (27) for passing one end of the rods through the inside of the rods to the outer wall of the rods. The third and fourth mold side walls are also provided with inner mold exhaust holes (28) for connecting the outer wall of the inner mold front mold core with the outside world.
7. The bolt forming die according to claim 5, characterized in that: The second mold, the third mold and the fourth mold respectively form three-stage two-stepped holes with diameters gradually expanding from one end to the other end. The front mold core of the inner mold and the rear mold core of the inner mold are inserted into the second step hole. One end of the front mold core of the inner mold is tightly against the step surface between the first step hole and the second step hole. A rear lock (29) is also provided. The rear lock is detachably fixed in the third step hole. The other end of the rear mold core of the inner mold is tightly against the surface of one end of the rear lock.
8. The bolt forming die according to claim 7, characterized in that: The inner mold rear mold core is a T-shaped structure with an outer diameter at one end larger than the outer diameter at the other end. The rear lock is threadedly connected to the third section step hole. A through hole is formed in the rear lock for inserting the other end of the inner mold rear mold core. One end of the rear lock is tightly against the step surface between the two ends of the inner mold rear mold core.
9. The bolt forming die according to claim 7, wherein: The punch on the first punch can be inserted into the inner hole of the first die, the punch on the second punch is formed with a funnel-shaped groove with a diameter at one end smaller than the diameter at the other end, the punch on the third punch is formed with a chamfered groove with low sides and high center, and the punch on the fourth punch is formed with a raised hexagonal boss (26) in the center.
Citation Information
Patent Citations
Plastic molding method of spherical hexagon bolt
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Bolt forming die
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