A cold heading and extruding die for improving the coaxiality of a product head rod

Abstract

The utility model relates to metal plastic deformation processing technical field especially relates to a cold heading extruding thin die for improving product head pole coaxial degree, including main mould cover, the main mould pad and extruding thin cavity mould core of setting in the main mould cover central hole, the lower end surface of extruding thin cavity mould core leans on the top surface of main mould pad, still be provided with the rod part guide mould core and head guide mould core in the main mould cover, the lower end surface of rod part guide mould core leans on the top surface of extruding thin cavity mould core, the lower end surface of head guide mould core leans on the top surface of rod part guide mould core, the coaxial setting of head guide mould core, rod part guide mould core, extruding thin cavity mould core, main mould pad's central through -hole, be provided with thimble in the central hole of main mould pad, and the upper end of thimble stretches into the central hole of extruding thin cavity mould core, still include the top rod, the upper end of top rod stretches into the central hole of main mould pad, and the top surface of top rod leans on the lower end surface of thimble.

Description

Technical Field

[0001] This utility model relates to the field of metal plastic deformation processing technology, and in particular to a cold heading extrusion die for improving the coaxiality of the product head rod. Background Technology

[0002] Combination Figure 1 The diagram shown is a structural schematic of a multi-step rod-type product. To save raw materials and improve the product's mechanical properties, the head of the product is upsetting, while the stepped parts on the rod are finished using an extrusion process.

[0003] In the prior art, for example, patent application CN105436380A discloses a cold forging combined female die for a blind rivet core rod. Another example is patent CN202263880U, which discloses a cold forging combined female die for processing blind rivet core rods using an upsetting method.

[0004] In the above-mentioned prior art, upsetting and extrusion are completed in the same station, which improves processing efficiency, but has the following disadvantages: (1) Upsetting requires the metal to expand radially, while extrusion requires the metal to contract axially or be locally refined. The two require opposite directions and forces for metal flow, which can easily lead to stress concentration inside the metal and may cause defects such as cracks and folds. (2) The instability of metal flow may cause the billet to shift, increase the scrap rate in the production process, and also affect the processing quality of subsequent processes, reducing the overall production efficiency. (3) The stress directions of the two deformations are opposite, and after superposition, a high stress zone will be formed inside the material. Especially in materials with poor plasticity, it is easy to cause micro cracks or even macro fractures.

[0005] Combination Figure 2 As shown, to solve the above problems, multi-station cold heading is adopted, including the following three methods: Method 1: The raw wire material is cut → the rod is extruded → the head is pre-upset → the head is precision upset. The disadvantage of this method is that it requires high precision of the mold. Different products require a different set of head forming molds for different extrusion lengths. The length cannot be freely adjusted, and the coaxiality of the head relative to the rod formed outside the main mold cannot be controlled.

[0006] Method 2: The process involves cutting the wire raw material → pre-upsetting the head → precision upsetting the head → extruding the rod. The disadvantage of this method is that the head and rod are exposed outside the main die in this open extrusion process. The head and rod are not subject to circumferential displacement restrictions within the die cavity. Therefore, uneven metal flow during open extrusion can lead to uneven circumferential stress, causing the head and rod to bend uncontrollably. When the extruded blank becomes unstable and bends beyond the largest cavity opening of the die, it will scrape against the die opening, causing scratches on the head or rod. Multi-step rod-type products often experience unstable extrusion quality and large head-rod coaxiality deviations, especially for extra-long rods, which are more prone to bending. This is essentially due to poor coaxiality between the head and rod, thus affecting the overall cold upsetting effect.

[0007] Method 3: The raw wire material is cut into pieces → pre-upsetting the head → fine upsetting the head → extruding the rod. During extrusion, the entire blank material is embedded inside the main mold. The mold is used to ensure the coaxiality of the product head and rod.

[0008] Method 3 is currently the most commonly used method. However, in the cold heading and refining of the rod section, a cold heading and refining die is required. When refining the rod section, a cold heading and refining die is urgently needed to meet the requirement that the blank material be embedded inside the main die. Utility Model Content

[0009] The main purpose of this utility model is to propose a cold heading extrusion die for improving the coaxiality of the product head rod, aiming to solve the above-mentioned technical problems.

[0010] To achieve the above objectives, this utility model proposes a cold heading extrusion die for improving the coaxiality of the product head rod, comprising a main die sleeve, a main die pad disposed in the central hole of the main die sleeve, and an extrusion cavity die core; the lower end face of the extrusion cavity die core abuts against the top surface of the main die pad; a rod guide die core and a head guide die core are also disposed in the main die sleeve; the lower end face of the rod guide die core abuts against the top surface of the extrusion cavity die core; the lower end face of the head guide die core abuts against the top surface of the rod guide die core; the head guide die core, rod guide die core, extrusion cavity die core, and the central through hole of the main die pad are coaxially disposed; an ejector pin is disposed in the central hole of the main die pad, and the upper end of the ejector pin extends into the central hole of the extrusion cavity die core; it also includes an ejector rod, the upper end of which extends into the central hole of the main die pad, and the top surface of the ejector rod abuts against the lower end face of the ejector pin.

[0011] Preferably, a main mold core sleeve is fitted on the outer peripheral surfaces of the head guide mold core, the rod guide mold core, and the extrusion cavity mold core; a main mold core outer sleeve is fitted on the outer peripheral surface of the main mold core sleeve; the outer peripheral surface of the main mold core outer sleeve mates with the inner hole surface of the main mold core sleeve; and the top surfaces of the head guide mold core, the main mold core sleeve, and the main mold core outer sleeve are flush with the top surface of the main mold core sleeve.

[0012] Preferably, the outer peripheral surfaces of the head guide mold core, the rod guide mold core, and the extrusion cavity mold core are all interference fits with the inner hole surface of the main mold core sleeve, and the interference amount is 0.15~0.18mm.

[0013] Preferably, a pin hole is provided in the middle of the main mold sleeve; a semi-circular limiting groove is provided in the outer circumferential surface of the main mold core sleeve; a locking pin is inserted into the pin hole and the locking pin is locked in the limiting groove.

[0014] Preferably, the inner hole of the outer sleeve of the main mold core is a tapered hole, and the outer cylindrical surface of the inner sleeve of the main mold core is a tapered surface; and the taper of the inner hole of the outer sleeve of the main mold core is equal to that of the outer cylindrical surface of the inner sleeve of the main mold core.

[0015] Preferably, the taper of the inner hole of the outer sleeve of the main mold core and the outer cylindrical surface of the inner sleeve of the main mold core is β, which satisfies: 2°≤β≤4°.

[0016] Preferably, the upper half of the central hole of the head guide mold core is configured as a tapered hole.

[0017] Preferably, the taper of the tapered hole is α, which satisfies: 8°≤α≤10°.

[0018] Preferably, the edge of the opening of the central hole of the guide mold core in the rod section is provided with a rounded corner.

[0019] Preferably, the diameter of the center hole of the main mold pad is larger than the diameter of the center hole of the lower half of the extrusion cavity mold core; the lower end of the ejector pin is configured as a limiting head, and the diameter of the limiting head is larger than the diameter of the center hole of the lower half of the extrusion cavity mold core; the outer peripheral surface of the limiting head slides in fit with the center hole of the main mold pad.

[0020] Due to the adoption of the above technical solution, the beneficial effects of this utility model are as follows: The cold heading and extrusion die provided by this utility model, due to the inclusion of a rod guide die core and a head guide die core, guides the rod portion of the blank and the head guide die core during the cold heading and extrusion operation. During cold heading and extrusion, the entire blank can be embedded within the die to withstand deformation, thus ensuring the coaxiality of the product's head and rod portion. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0022] Figure 1 A structural schematic diagram of a multi-step rod-type product; Figure 2 Schematic diagrams of three methods for cold heading using multiple workstations; Figure 3 A cross-sectional view of the cold heading extrusion die provided by this utility model; Figure 4 for Figure 3 Enlarged view of point A in the middle; Figure 5 This is a three-dimensional structural diagram of the main mold sleeve in this utility model; Figure 6 This is a three-dimensional structural diagram of the outer sleeve of the main mold core in this utility model; Figure 7 This is a schematic diagram of the raw material obtained after the fine upsetting of the head; Figure 8 This is a schematic diagram illustrating the working principle of the cold heading and extrusion die provided by this utility model.

[0023] Explanation of reference numerals: 1. Main mold sleeve; 1a. Pin hole; 2. Main mold core assembly; 3. Mold locking bevel; 4. Blank; 5. Main mold pad; 6. Ejector pin; 6a. Limiting head; 7. Ejector rod; 8. Main mold core outer sleeve; 8a. Limiting groove; 9. Main mold core middle sleeve; 10. Extrusion cavity mold core; 10a. First hole section; 10b. Second hole section; 10c. Third hole section; 10d. Fourth hole section; 10e. Fifth hole section; 11. Mold locking pin; 12. Rod guide mold core; 12a. Rounded corner; 13. Head guide mold core; 13a. Tapered hole; 14. Extrusion station parts. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0025] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0026] Furthermore, the use of terms such as "first" and "second" in this utility model is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.

[0027] Combination Figures 3 to 6 The image shows a specific embodiment of a cold heading extrusion die for improving the coaxiality of the product head rod provided by this utility model. The cold heading extrusion die includes a main die sleeve 1, a main die pad 5 disposed within the central hole of the main die sleeve 1, and an extrusion cavity die core 10. The lower end face of the extrusion cavity die core 10 abuts against the top surface of the main die pad 5. A rod guide die core 12 and a head guide die core 13 are also disposed within the main die sleeve 1. The lower end face of the rod guide die core 12 abuts against the top surface of the extrusion cavity die core 10. The lower end face of the head guide die core 13 abuts against the top surface of the rod guide die core 12. The central through holes of the head guide die core 13, rod guide die core 12, extrusion cavity die core 10, and main die pad 5 are coaxially arranged. An ejector pin 6 is disposed within the central hole of the main die pad 5, and the upper end of the ejector pin 6 extends into the central hole of the extrusion cavity die core 10.

[0028] The cold heading extrusion die also includes an ejector pin 7, the upper end of which extends into the center hole of the main die pad 5, and the top surface of the ejector pin 7 abuts against the lower end surface of the ejector pin 6.

[0029] Combination Figure 3 As shown, a main mold core sleeve 9 is fitted on the outer peripheral surfaces of the head guide mold core 13, the rod guide mold core 12, and the extrusion cavity mold core 10; a main mold core outer sleeve 8 is fitted on the outer peripheral surface of the main mold core sleeve 9; the outer peripheral surface of the main mold core outer sleeve 8 mates with the inner hole surface of the main mold sleeve 1; the top surfaces of the head guide mold core 13, the main mold core sleeve 9, and the main mold core outer sleeve 8 are flush with the top surface of the main mold sleeve 1.

[0030] Combination Figure 3 , Figure 5 and Figure 6As shown, a pin hole 1a is provided horizontally on the main mold sleeve 1; a semi-circular limiting groove 8a is provided horizontally on the outer circumferential surface of the main mold core sleeve 8; a locking pin 11 is inserted into the pin hole 1a, and the locking pin 11 is locked in the limiting groove 8a.

[0031] During assembly, the extrusion cavity mold core 10, the rod guide mold core 12, and the head guide mold core 13 are sequentially pressed into the main mold core sleeve 9. The outer circumferential surfaces of the head guide mold core 13, the rod guide mold core 12, and the extrusion cavity mold core 10 are all interference-fitted with the inner hole surface of the main mold core sleeve 9, with an interference amount of 0.15~0.18mm. The main mold core sleeve 9 is then pressed into the main mold core outer sleeve 8 for an interference fit, forming the main mold core assembly 2. The main mold pad 5 and the main mold core assembly 2 are installed into the main mold sleeve 1, and then a locking pin 11 is inserted into the pin hole 1a, causing the locking pin 11 to engage in the limiting groove 8a of the main mold core outer sleeve 8.

[0032] Combination Figure 3 As shown, the inner hole of the main mold core outer sleeve 8 is a tapered hole, and the outer cylindrical surface of the main mold core middle sleeve 9 is a tapered surface; and the taper of the inner hole of the main mold core outer sleeve 8 and the taper of the outer cylindrical surface of the main mold core middle sleeve 9 are equal. Specifically, the taper of the inner hole of the main mold core outer sleeve 8 and the taper of the outer cylindrical surface of the main mold core middle sleeve 9 is β, satisfying: 2°≤β≤4°. When the product is ejected after the cold heading and extrusion operation, by adopting the above structure, the upward movement of the main mold core middle sleeve 9 relative to the main mold core outer sleeve 8 can be effectively avoided.

[0033] Combination Figure 3 As shown, the upper half of the central hole of the head guide mold core 13 is configured as a tapered hole 13a. Specifically, the taper of the tapered hole 13a is α, satisfying: 8°≤α≤10°. A rounded corner 12a is provided on the edge of the opening of the central hole of the rod guide mold core 12.

[0034] In this embodiment, the effective height of the center hole of the head guide mold core 13 is much higher than the head height of the blank 4, which ensures that the head remains within the center hole of the head guide mold core 13 when the extrusion length is adjusted within a certain range. Specifically, the center hole of the head guide mold core 13 is not less than 5 times the head height of the blank 4.

[0035] Combination Figure 4As shown, the central hole of the extrusion cavity mold core 10 includes, from top to bottom, a first hole segment 10a, a second hole segment 10b, a third hole segment 10c, a fourth hole segment 10d, and a fifth hole segment 10e; wherein: the diameter of the third hole segment 10c is smaller than the diameter of the fifth hole segment 10e, and the diameter of the fifth hole segment 10e is smaller than the diameter of the first hole segment 10a. The diameter of the first hole segment 10a is equal to the diameter of the central hole of the rod guide mold core 12. The second hole segment 10b and the fourth hole segment 10d are both tapered holes. The first hole segment 10a and the third hole segment 10c are connected by the tapered second hole segment 10b; the third hole segment 10c and the fifth hole segment 10e are connected by the tapered fourth hole segment 10d. The third hole segment 10c forms a necked hole.

[0036] Combination Figure 3 As shown, the diameter of the center hole of the main mold pad 5 is larger than the diameter of the center hole of the lower half of the extrusion cavity mold core 10; the lower end of the ejector pin 6 is configured as a limiting head 6a, and the diameter of the limiting head 6a is larger than the diameter of the center hole of the lower half of the extrusion cavity mold core 10. That is, the diameter of the center hole of the main mold pad 5 is larger than the diameter of the fifth hole segment 10e, and the diameter of the limiting head 6a is larger than the diameter of the fifth hole segment 10e. The outer peripheral surface of the limiting head 6a slides in fit with the center hole of the main mold pad 5. By adopting the above structure, when the ejector rod 7 pushes the ejector pin 6 upward, when the ejector pin 6 moves upward to the limit position, the limiting head 6a can abut against the lower end surface of the extrusion cavity mold core 10 to form a limit.

[0037] Combination Figure 3 As shown, a locking bevel 3 is provided on the outer circumferential surface of the main mold sleeve 1. The lower end face of the main mold pad 5 is higher than the lower end face of the main mold sleeve 1.

[0038] Combination Figure 7 and Figure 8 As shown, the working principle of the cold heading extrusion die provided by this utility model is as follows: This cold heading die is used to perform heading and fine heading of the rod body of blank 4. The head of blank 4 has already completed the fine heading process, that is, blank 4 is the blank after the head has been finely headed.

[0039] During the cold heading and refining operation, the rod of the blank 4 passes sequentially through the head guide mold core 13 and the rod guide mold core 12 to reach the first hole section 10a in the refining cavity mold core 10. Under the thrust of the punch (not shown in the figure) on the equipment, the blank 4 moves downward, and under the guidance of the lower end of the rod of the blank 4 in the second hole section 10b, it enters the third hole section 10c for refining. The punch continues to descend, and the rod of the blank 4 is continuously refined. After refining, the rod enters the fourth hole section 10d through the refining cavity mold core 10 and then enters the fifth hole section 10e.

[0040] During the extrusion process, the head of the blank 4 remains within the central hole of the head guide mold core 13, which guides the head of the blank 4. The central hole of the rod guide mold core 12 guides the rods on the blank 4. Therefore, during extrusion, the head of the blank 4 is restricted circumferentially by the central hole of the head guide mold core 13, while the uncrushed rods of the blank 4 are restricted circumferentially by the central hole of the rod guide mold core 12. When the tail end of the product rod experiences extrusion resistance, this resistance is transmitted to the head and the uncrushed rods, preventing bending or displacement and thus avoiding scratch defects. This ensures the overall forming quality of the product during extrusion.

[0041] After extrusion, part 14 of the extrusion station is obtained.

[0042] When the predetermined extrusion length is reached, the punch stops advancing and moves upward with the die to begin unloading. After the extrusion process is completed, the feeding mechanism (not shown in the figure) on the equipment is activated. The feeding rod pushes the push rod 7 upward in the inner hole of the main die pad 5, thereby pushing the ejector pin 6 upward to eject the extrusion station part 14 until it is completely ejected from the end face of the main die sleeve 1, completing one processing cycle of the extrusion station.

[0043] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the concept of the present utility model and using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present utility model.

Claims

1. A cold heading extrusion die for improving the coaxiality of a product head rod, comprising a main die sleeve (1), a main die pad (5) disposed in the central hole of the main die sleeve (1), and an extrusion cavity die core (10); the lower end face of the extrusion cavity die core (10) abuts against the top surface of the main die pad (5); characterized in that: The main mold sleeve (1) is also provided with a rod guide mold core (12) and a head guide mold core (13). The lower end face of the rod guide mold core (12) abuts against the top surface of the extrusion cavity mold core (10); The lower end face of the head guide mold core (13) abuts against the top surface of the rod guide mold core (12); The head guide mold core (13), the rod guide mold core (12), the extrusion cavity mold core (10), and the main mold pad (5) are coaxially arranged with their central through holes. An ejector pin (6) is provided in the center hole of the main mold pad (5), and the upper end of the ejector pin (6) extends into the center hole of the extrusion cavity mold core (10); It also includes a push rod (7), the upper end of which extends into the center hole of the main mold pad (5), and the top surface of the push rod (7) abuts against the lower end surface of the ejector pin (6).

2. The cold heading extrusion die as described in claim 1, characterized in that, A main mold core sleeve (9) is fitted on the outer circumferential surface of the head guide mold core (13), the rod guide mold core (12), and the extrusion cavity mold core (10); A main mold core outer sleeve (8) is fitted on the outer circumferential surface of the main mold core sleeve (9); The outer peripheral surface of the main mold core sleeve (8) is matched with the inner hole surface of the main mold sleeve (1); The top surfaces of the head guide core (13), the main core sleeve (9), and the main core outer sleeve (8) are flush with the top surface of the main sleeve (1).

3. The cold heading extrusion die as described in claim 2, characterized in that, The outer peripheral surfaces of the head guide mold core (13), the rod guide mold core (12), and the extrusion cavity mold core (10) are all interference fits with the inner hole surface of the main mold core sleeve (9), with an interference amount of 0.15~0.18mm.

4. The cold heading extrusion die as described in claim 2, characterized in that, A pin hole (1a) is provided in the middle of the main mold sleeve (1) in the transverse direction; A semi-circular limiting groove (8a) is provided laterally on the outer peripheral surface of the main mold core sleeve (8). A locking pin (11) is inserted into the pin hole (1a), and the locking pin (11) is engaged in the limiting groove (8a).

5. The cold heading extrusion die as described in claim 2, characterized in that, The inner hole of the main mold core sleeve (8) is a tapered hole, and the outer cylindrical surface of the main mold core middle sleeve (9) is a tapered surface; and the taper of the inner hole of the main mold core sleeve (8) and the outer cylindrical surface of the main mold core middle sleeve (9) are equal.

6. The cold heading extrusion die as described in claim 5, characterized in that, The taper of the inner hole of the outer sleeve (8) of the main mold core and the outer cylindrical surface of the inner sleeve (9) of the main mold core is β, which satisfies: 2°≤β≤4°.

7. The cold heading extrusion die as described in claim 1, characterized in that, The upper half of the central hole of the head guide core (13) is set as a tapered hole (13a).

8. The cold heading extrusion die as described in claim 7, characterized in that, The taper of the tapered hole (13a) is α, which satisfies: 8°≤α≤10°.

9. The cold heading extrusion die as described in claim 1, characterized in that, The opening edge of the central hole of the rod guide mold core (12) is provided with a rounded corner (12a).

10. The cold heading extrusion die as described in claim 1, characterized in that, The diameter of the center hole of the main mold pad (5) is larger than the diameter of the center hole of the lower half of the extrusion cavity mold core (10); The lower end of the ejector pin (6) is set as a limiting head (6a), and the diameter of the limiting head (6a) is larger than the diameter of the center hole of the lower half of the extrusion cavity mold core (10). The outer peripheral surface of the limiting head (6a) slides in conjunction with the center hole of the main mold pad (5).

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