Screw cold heading forming die

Abstract

The utility model discloses a screw cold heading forming die which comprises a forming die shell, a first through hole, a second through hole, a third through hole, a plum blossom-shaped through hole and an installation groove are sequentially formed in the center of the end wall of the forming die shell from top to bottom, and an annular end is installed at the top end of the forming die shell. A neck bush is arranged between the annular end and the forming die shell, a die cavity is formed in the center of the end wall of the neck bush, an ejector block is arranged in the die cavity and installed at the top end of a connecting rod, and the bottom end of the connecting rod sequentially penetrates through a second through hole and a third through hole to be connected with a plum blossom-shaped connecting block. According to the forming die, a worker can conveniently disassemble, assemble and replace a structure which is easy to damage on the forming die, the situation that the whole forming die is scrapped due to the fact that an end on the forming die is damaged or a die cavity on the forming die is damaged is avoided, the production cost is reduced, and the production efficiency is improved.

Description

Technical Field

[0001] This utility model relates to the field of cold heading forming molds for screws, specifically a cold heading forming mold for screws. Background Technology

[0002] Cold heading of screws is a high-efficiency processing method that uses a stamping head to apply high-frequency impact force to a die, causing the metal blank to undergo plastic deformation at room temperature, thereby forming a screw. This process has the characteristics of high production efficiency, high material utilization, and stable forming accuracy, and is widely used in the automotive, electronics, and machinery manufacturing industries. However, in the cold heading process, the die is the core component, and its structural design directly affects product quality, production efficiency, and production costs.

[0003] A search revealed that patent publication number CN218134729U discloses a cold heading die assembly for a self-tapping locking sleeve screw, comprising a punch assembly and a main die assembly. The punch assembly includes a first punch, a second punch, a third punch, and a fourth punch, with a first punch, a second punch, a third punch, and a fourth punch sequentially arranged on the end faces of the first, second, third, and fourth punches. The main die assembly includes a first main die, a second main die, a third main die, and a fourth main die, with a first punch cavity, a second punch cavity, a third punch cavity, and a fourth punch cavity respectively within each of the first, second, third, and fourth main dies. This invention solves the problem of bolt loosening after assembly compared to older technologies. The internal threads connect different parts through different bolts, resulting in higher installation efficiency and safer construction compared to older technologies.

[0004] In existing cold heading dies for screws, the stamping head directly contacts the end of the forming die during use. During each cold heading process, the end must withstand instantaneous impact forces of hundreds to thousands of Newtons. Prolonged, high-frequency impacts can easily lead to fatigue cracks, chipping, or localized collapse at the die end, affecting the screw head forming accuracy and even causing die breakage, resulting in production line downtime for repairs. Traditional die ends are often integrated with the main body; once damaged, the entire die must be replaced, resulting in high replacement costs (die materials are mostly high-speed steel or cemented carbide, accounting for 20%-30% of production costs) and time-consuming replacement processes. The process is relatively long (each replacement takes 2-4 hours), which affects production efficiency. During the cold heading process, the metal blank flows plastically in the mold cavity, causing severe friction on the inner wall of the mold cavity. Especially when producing high-strength screws (such as grade 8.8 and above), the wear rate is even faster. When the wear of the mold cavity causes the screw dimensions to be out of tolerance, traditional molds need to be repaired by electrical discharge machining or grinding. The cost of a single repair is about 15%-20% of the original value of the mold, and the life of the repaired mold is only 60%-70% of that of a new mold. If the wear is severe, the entire mold needs to be replaced, further increasing the cost. Therefore, a screw cold heading forming mold was designed. Utility Model Content

[0005] In view of the defects or deficiencies of the cold heading forming mold for screws, the purpose of this utility model is to provide a cold heading forming mold for screws that makes it easy for workers to disassemble and replace the easily damaged structures on the forming mold, and avoids the situation where the entire forming mold is scrapped due to damage to the end of the forming mold or damage to the mold cavity.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0007] This utility model provides a cold heading die for screws, including a die housing. A first through hole, a second through hole, a third through hole, a plum blossom-shaped through hole, and a mounting groove are sequentially formed from top to bottom at the center of the end wall of the die housing. An annular end is installed at the top of the die housing, and an inner bushing is provided between the annular end and the die housing. A die cavity is formed at the center of the end wall of the inner bushing, and a top block is provided inside the die cavity. The top block is installed at the top of a connecting rod. The bottom end of the connecting rod sequentially passes through the second and third through holes and connects to the plum blossom-shaped connecting block, which is located inside the plum blossom-shaped through hole. A bottom cover is installed in the mounting groove, and a spring is provided inside the plum blossom-shaped through hole, located between the bottom end of the plum blossom-shaped connecting block and the top end of the bottom cover.

[0008] Preferably, the top end of the inner sleeve is located inside the annular end, the bottom end of the inner sleeve is located inside the first through hole, the outer diameter of the inner sleeve is equal to the inner diameter of the annular end, and the outer diameter of the inner sleeve is equal to the diameter of the first through hole.

[0009] Preferably, the annular end is fixedly connected to the molding die housing by fastening bolts. U-shaped protrusions are provided on both sides of the circumferential outer wall of the annular end, and grooves are provided on both sides of the top of the annular end. The U-shaped grooves on the U-shaped protrusions are connected to the grooves.

[0010] Preferably, connecting protrusions are provided on the upper sides of both sides of the outer circumferential wall of the inner bushing, and the connecting protrusions are located in the groove and the U-shaped groove on the U-shaped protrusion. The connecting protrusions and the U-shaped protrusions are fixedly connected by fastening bolts, and the outer wall of the connecting protrusions is in clearance fit with the groove wall of the groove and the groove wall of the U-shaped groove.

[0011] Preferably, both ends of the connecting rod are threadedly connected to the plum blossom-shaped connecting block and the top block, and the outer wall of the plum blossom-shaped connecting block is clearance-fitted to the wall of the plum blossom-shaped through hole.

[0012] Preferably, the bottom cover and the molding die housing are fixedly connected by fastening bolts.

[0013] Compared with existing technologies, one or more of the above technical solutions have the following beneficial effects:

[0014] 1. In this utility model, through a series of structural arrangements, when the annular end is subjected to high-frequency impact from the stamping head for a long time, resulting in fatigue cracks, chipping, or local collapse, the annular end and the mold housing are designed as separate units, and the mold housing and the annular end are fixedly connected by fastening bolts. This makes it convenient for workers to disassemble and replace the annular end. Compared with the prior art, when the annular end on this forming mold is damaged, only the annular end needs to be disassembled and replaced, without replacing the entire forming mold. This reduces production costs and the time required for replacement, thereby improving production efficiency.

[0015] In this invention, through a series of structural arrangements, when the cavity wall wears and causes the screw dimensions to exceed tolerances, the cavity is located on the inner bushing. The inner bushing is designed to be separate from the annular end and the mold housing, and the inner bushing is fixedly connected to the annular end by fastening bolts. This allows workers to easily disassemble and replace the inner bushing. Compared to the prior art, when the cavity of this molding die is worn, only the inner bushing needs to be disassembled and replaced, without replacing the entire molding die. This further reduces production costs and improves production efficiency. Attached Figure Description

[0016] The accompanying drawings, which form part of this specification, are used to provide a further understanding of this utility model. The illustrative embodiments of this utility model and their descriptions are used to explain this utility model and do not constitute an improper limitation of this utility model.

[0017] Figure 1 This is a schematic diagram of the overall three-dimensional structure of this utility model. Figure 1 .

[0018] Figure 2 This is a schematic diagram of the overall three-dimensional structure of this utility model. Figure 2 .

[0019] Figure 3 This is an exploded structural diagram of the present invention.

[0020] Figure 4 This is a cross-sectional view of the present invention.

[0021] Figure 5 This is a schematic diagram of the structure of the mold shell of this utility model.

[0022] Figure 6 This is a schematic diagram of the structure of the annular end of this utility model.

[0023] Figure 7This is a schematic diagram of the structure of the inner liner of this utility model.

[0024] Figure 8 This is a cross-sectional view of the connection structure between the top block, connecting rod, and plum blossom-shaped connecting block of this utility model.

[0025] In the picture:

[0026] 100. Annular end; 110. U-shaped protrusion; 120. Groove;

[0027] 200, Inner bushing; 210, Connecting protrusion; 220, Mold cavity;

[0028] 300. Molding mold housing; 310. First through hole; 320. Second through hole; 330. Third through hole; 340. Plum blossom-shaped through hole; 350. Mounting groove;

[0029] 400. Bottom cover;

[0030] 500, Top Block;

[0031] 600. Connecting rod;

[0032] 700. Plum blossom-shaped connecting block;

[0033] 800, Spring. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0035] It should be noted that the following detailed description is exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0036] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0037] like Figure 1-8As shown, a cold heading die for screws includes a die housing 300. A first through hole 310, a second through hole 320, a third through hole 330, a plum blossom-shaped through hole 340, and a mounting groove 350 are sequentially formed from top to bottom at the center of the end wall of the die housing 300. An annular end head 100 is mounted on the top of the die housing 300. An inner bushing 200 is provided between the annular end head 100 and the die housing 300. A die cavity 220 is formed at the center of the end wall of the inner bushing 200. A top block 500 is provided inside the die cavity 220 and is mounted on the top of a connecting rod 600. The bottom end of the connecting rod 600 passes through the second through hole 310, the second through hole 320, and the third through hole 330. Hole 320 and third through hole 330 are connected to plum blossom-shaped connecting block 700, and plum blossom-shaped connecting block 700 is located in plum blossom-shaped through hole 340. Bottom cover 400 is installed in mounting groove 350. Spring 800 is installed inside plum blossom-shaped through hole 340, and spring 800 is located between bottom end of plum blossom-shaped connecting block 700 and top end of bottom cover 400. With the cooperation of top block 500, spring 800, connecting rod 600 and other structures, when the stamping structure stamps the screw on this forming mold and moves to the initial position, top block 500 can push the formed screw out part of the mold cavity 220 under the rebound force of spring 800.

[0038] The top end of the inner bushing 200 is located inside the annular end 100, and the bottom end of the inner bushing 200 is located inside the first through hole 310. The outer diameter of the inner bushing 200 is equal to the inner diameter of the annular end 100, and the outer diameter of the inner bushing 200 is equal to the diameter of the first through hole 310.

[0039] The annular end 100 is fixedly connected to the molding die housing 300 by fastening bolts. U-shaped protrusions 110 are provided on both sides of the circumferential outer wall of the annular end 100, and grooves 120 are provided on both sides of the top of the annular end 100. The U-shaped grooves on the U-shaped protrusions 110 are connected to the grooves 120.

[0040] Connecting protrusions 210 are provided on the upper sides of both sides of the outer wall of the inner bushing 200. The connecting protrusions 210 are located in the groove 120 and the U-shaped groove on the U-shaped protrusion 110. The connecting protrusions 210 and the U-shaped protrusion 110 are fixedly connected by fastening bolts. The outer wall of the connecting protrusion 210 is clearance-fitted with the groove wall of the groove 120 and the groove wall of the U-shaped groove. Since the outer diameter of the inner bushing 200 is equal to the inner diameter of the annular end 100 and the outer diameter of the inner bushing 200 is equal to the diameter of the first through hole 310, the annular end 100 is fixedly connected to the molding mold housing 300 by fastening bolts. The outer wall of the connecting protrusion 210 is clearance-fitted with the groove wall of the groove 120 and the groove wall of the U-shaped groove. Therefore, after the worker removes the fastening bolts connecting the connecting protrusions 210 and the U-shaped protrusion 110, the worker can remove the inner bushing 200.

[0041] Both ends of the connecting rod 600 are threadedly connected to the plum blossom-shaped connecting block 700 and the top block 500. Because both ends of the connecting rod 600 are threadedly connected to the plum blossom-shaped connecting block 700 and the top block 500, it is convenient for workers to disassemble and replace the connecting rod 600, the plum blossom-shaped connecting block 700 and the top block 500. The outer wall of the plum blossom-shaped connecting block 700 is clearance-fitted with the wall of the plum blossom-shaped through hole 340. Because the outer wall of the plum blossom-shaped connecting block 700 is clearance-fitted with the wall of the plum blossom-shaped through hole 340, it can limit and guide the movement of the plum blossom-shaped connecting block 700 and the top block 500.

[0042] The bottom cover 400 is fixedly connected to the molding mold housing 300 by fastening bolts. Because the bottom cover 400 is fixedly connected to the molding mold housing 300 by fastening bolts, the operator can disassemble and assemble the bottom cover 400. After the bottom cover 400 is disassembled, the operator can remove the spring 800, the connecting rod 600, the plum blossom-shaped connecting block 700 and the top block 500.

[0043] Working Principle: When the annular end 100 suffers fatigue cracks, chipping, or localized collapse due to prolonged high-frequency impact from the stamping head, the annular end 100 can be easily disassembled and replaced by the mold housing, which is a separate design. The mold housing and the annular end 100 are fixed together by fastening bolts. Compared to existing technologies, when the annular end 100 on this forming mold is damaged, only the annular end 100 needs to be disassembled and replaced; the entire forming mold does not need to be replaced, thus reducing production costs and replacement time. This improves production efficiency. When the cavity wall of the mold cavity 220 wears down, causing the screw dimensions to exceed tolerances, the mold cavity 220 is located on the inner bushing 200. The inner bushing 200 is designed to be separate from the annular end 100 and the mold housing, and the inner bushing 200 is fixedly connected to the annular end 100 by fastening bolts. This makes it easy for workers to disassemble and replace the inner bushing 200. Compared with the prior art, when the mold cavity 220 on this molding die is worn, only the inner bushing 200 needs to be disassembled and replaced, without replacing the entire molding die. This further reduces production costs and improves production efficiency.

[0044] The above description is merely a preferred embodiment of this utility model and is not intended to limit the invention. For those skilled in the art, various modifications and variations can be made to this invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the protection scope of this invention.

Claims

1. A cold heading die for screws, comprising a die housing (300), characterized in that: The center of the end wall of the molding die housing (300) is provided with a first through hole (310), a second through hole (320), a third through hole (330), a plum blossom-shaped through hole (340), and a mounting groove (350) from top to bottom. An annular end head (100) is installed at the top of the molding die housing (300). An inner bushing (200) is provided between the annular end head (100) and the molding die housing (300). A mold cavity (220) is provided at the center of the end wall of the inner bushing (200). A top block (5) is provided in the mold cavity (220). 00), and the top block (500) is installed at the top of the connecting rod (600). The bottom end of the connecting rod (600) passes through the second through hole (320) and the third through hole (330) in sequence and is connected to the plum blossom-shaped connecting block (700). The plum blossom-shaped connecting block (700) is located in the plum blossom-shaped through hole (340). The bottom cover (400) is installed in the mounting groove (350). The plum blossom-shaped through hole (340) is provided with a spring (800). The spring (800) is located between the bottom end of the plum blossom-shaped connecting block (700) and the top end of the bottom cover (400).

2. The screw cold heading forming die according to claim 1, characterized in that: The top end of the inner sleeve (200) is located inside the annular end (100), the bottom end of the inner sleeve (200) is located inside the first through hole (310), the outer diameter of the inner sleeve (200) is equal to the inner diameter of the annular end (100), and the outer diameter of the inner sleeve (200) is equal to the diameter of the first through hole (310).

3. The screw cold heading forming die according to claim 1, characterized in that: The annular end (100) is fixedly connected to the molding die housing (300) by fastening bolts. U-shaped protrusions (110) are provided on both sides of the circumferential outer wall of the annular end (100), and grooves (120) are provided on both sides of the top of the annular end (100). The U-shaped groove on the U-shaped protrusion (110) is connected to the groove (120).

4. The screw cold heading forming die according to claim 1, characterized in that: The inner liner (200) has connecting protrusions (210) on both sides of the outer wall of the circumferential direction. The connecting protrusions (210) are located in the groove (120) and the U-shaped groove on the U-shaped protrusion (110). The connecting protrusions (210) and the U-shaped protrusions (110) are fixedly connected by fastening bolts. The outer wall of the connecting protrusions (210) is in clearance fit with the groove wall of the groove (120) and the groove wall of the U-shaped groove.

5. The cold heading die for screws according to claim 1, characterized in that: Both ends of the connecting rod (600) are threadedly connected to the plum blossom-shaped connecting block (700) and the top block (500), and the outer wall of the plum blossom-shaped connecting block (700) is clearance-fitted to the wall of the plum blossom-shaped through hole (340).

6. The cold heading die for screws according to claim 1, characterized in that: The bottom cover (400) and the molding die housing (300) are fixedly connected by fastening bolts.

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