Plough-shaped bolt forming process and forming die thereof

Abstract

The invention relates to the technical field of plow-shaped bolt stamping and forging, in particular to a plow-shaped bolt forming process and a forming die thereof.The plow-shaped bolt forming process comprises the following steps that S1, a wire to be machined is subjected to cold heading and stamping, part of the four sides of the wire to be machined are gradually restrained in the axial direction to form a rounded rectangular column, and the rounded rectangular column reaches the preset length; part of the four corners of the rounded rectangular column are gradually restrained in the axial direction to form a cylindrical rod with the preset length, the roughly machined bolt is obtained, and the diameter of the cylindrical rod is smaller than that of the wire to be machined; s2, the part, making contact with the cylindrical rod, in the mold is not changed, other parts are replaced, and the roughly machined bolt is restrained; and S3, cold heading stamping is conducted on the roughly machined bolt, the part, making contact with the cylindrical rod, of the rounded rectangular column and the rounded rectangular column are extruded and deformed into a square part, the part, making contact with the to-be-machined wire rod, of the rounded rectangular column and the remaining part of the to-be-machined wire rod are extruded and deformed into a head part, and the plough-shaped bolt is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of plow-shaped bolt stamping and forging, and in particular to a plow-shaped bolt forming process and a forming die thereof. Background Art

[0002] The plow bolt includes a rod, a head and a square part; the plow bolt has better performance than standard fasteners and is usually used to fix engineering machinery grader blades, etc., with good fixing effect and large usage. Due to the large deformation of the head during bolt forming, the red beating process is now mostly used. The red beating process is easy to form, but it also has certain disadvantages, such as defects caused by chemical changes in the outer layer of the blank, such as scale, decarburization, and carbon increase; there are also defects caused by abnormal changes in the internal structure, such as overburning, overheating, and incomplete heating; and cracks caused by excessive stress due to uneven temperature distribution inside the blank. In addition, the red beating efficiency is low, and the rod is easy to expand when the short rod is formed by red beating, which usually requires an additional grinding process for the blank diameter, which increases the cost. Therefore, some plow bolts are now formed by cold heading process, but the processing is difficult due to the non-standard cold heading steps.

[0003] How to improve the processing technology of the plow-shaped bolt and enhance its forming quality has become a technical problem that needs to be solved by those skilled in the art.

[0004] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not constitute the prior art that is already known to one of ordinary skill in the art. Summary of the invention

[0005] The purpose of the present invention is to design a cold heading process and a forming die for a plow-shaped bolt to solve the above-mentioned shortcomings in the technology.

[0006] In order to achieve the above object, the present invention provides the following technical solution: a plow-shaped bolt forming process, which is used to cold-forge and extrude the wire to be processed on the same mold to form a plow-shaped bolt, comprising the following steps: S1: cold heading and stamping the wire to be processed, gradually constraining the four sides of part of the wire to be processed along the axial direction to form a rounded rectangular column, and when the rounded rectangular column reaches a predetermined length, gradually constraining the four corners of part of the rounded rectangular column along the axial direction to form a cylindrical rod of a preset length, thereby obtaining a rough-machined bolt, wherein the diameter of the cylindrical rod is smaller than the diameter of the wire to be processed; S2: The part of the die that contacts the cylindrical rod remains unchanged, and the rest is replaced to constrain the rough-machined bolts; S3: cold heading and stamping the rough-machined bolt, the portion where the rounded rectangular column contacts the cylindrical rod and the rounded rectangular column are extruded and deformed into a square portion, and the portion where the rounded rectangular column contacts the wire to be processed and the remaining portion of the wire to be processed are extruded and deformed into a head portion, thereby obtaining a plow-shaped bolt; S4: The part of the die that contacts the cylindrical rod remains unchanged, and the plow bolt is removed when the rest of the die is replaced; S5: After the rest of the die is replaced, the new wire to be processed is cold headed.

[0007] In the second aspect, the present invention also provides a plow-shaped bolt forming mold applied to the claim 1, comprising a mold shell, a first slide groove and a second slide groove opened in the mold shell, a first upper mold core and a second upper mold core slidably installed in the first slide groove and the second slide groove, and a lower mold core fixedly installed in the mold shell, the first upper mold core and the second upper mold core can be half-separated for mold closing and mold opening, the first upper mold core and the lower mold core are used to extrude the wire to be processed to form the rough-processed bolt when the first upper mold core and the lower mold core are used to extrude the rough-processed bolt to form a plow-shaped bolt when the second upper mold core and the lower mold core are used to extrude the rough-processed bolt to form a plow-shaped bolt when the second upper mold core and the lower mold core are used to extrude the rough-processed bolt to form a plow-shaped bolt.

[0008] Preferably, the first upper mold core includes a first mold core for accommodating the wire to be processed for guiding, a second mold core for extruding part of the wire to be processed to form a rounded rectangular column, a third mold core for obtaining a rounded rectangular column of a predetermined length, and a fourth mold core for extruding part of the rounded rectangular column to form a cylindrical rod, and the first mold core, the second mold core, the third mold core and the fourth mold core respectively have a coaxially arranged first compression hole, a second compression hole, a third compression hole and a fourth compression hole.

[0009] Preferably, the second upper mold core includes a fifth mold core for accommodating the rough-machined bolt, a sixth mold core for extruding to form a head, and a seventh mold core for extruding to form a square portion, and the fifth mold core, the sixth mold core and the seventh mold core respectively have a coaxially arranged fifth compression hole, a sixth compression hole and a seventh compression hole, and the seventh mold core and the fourth mold core are slidably connected to the first slide groove and the second slide groove respectively.

[0010] Preferably, the rounded rectangles formed by the third compression hole and the seventh compression hole on the horizontal plane have the same length and width, and the rounded radius of the third compression hole is greater than the rounded radius of the seventh compression hole.

[0011] Preferably, the top surface of the second compression hole is a circle with the same shape as the horizontal cross-section of the first compression hole, the bottom surface of the second compression hole and the top surface of the fourth compression hole are both rounded rectangles with the same shape as the horizontal cross-section of the third compression hole, and the bottom surface of the fourth compression hole is a circle with the same diameter as the width of the rounded rectangle.

[0012] Preferably, the lower mold core comprises a lower mold core fixedly installed in the mold shell, and an eighth compression hole is provided in the lower mold core, and the diameter of the eighth compression hole is the same as the bottom diameter of the fourth compression hole.

[0013] Preferably, the diameter of the fifth compression hole is larger than the diameter of the first compression hole, and the diameter of the first compression hole is larger than the diameter of the eighth compression hole.

[0014] Preferably, when the mold is opened, the first upper mold core is separated into two halves with the diagonal line of the third compression hole as the center line, and when the mold is opened, the second upper mold core is separated into two halves with the diagonal line of the seventh compression hole as the center line.

[0015] Preferably, four hydraulic assemblies are installed on the mold shell, and output ends of two hydraulic assemblies are symmetrically installed on the first upper mold core, and output ends of the other two hydraulic assemblies are symmetrically installed on the second upper mold core.

[0016] In the above technical solution, the technical effects and advantages provided by the present invention are: The present invention uses a secondary cold heading stamping method to first stamp the wire material to be processed into the shape of a rough-machined bolt, and then uses a second cold heading stamping method to stamp the rough-machined bolt into a complete plow-shaped bolt, thereby realizing cold heading stamping. Compared with hot heading, no additional blank diameter grinding process is required, thereby improving the forming quality. The present invention firstly uses the second compression hole to gradually constrain the four sides of a part of the wire material to be processed along the axial direction to form a rounded rectangular column, and when the rounded rectangular column has a predetermined length, the four corners of the rounded rectangular column are gradually constrained along the axial direction to form a cylindrical rod of a preset length, thereby obtaining a rough-machined bolt. In the process of changing the large diameter of the wire material to be processed into a small diameter cylindrical rod, firstly, the deformation is divided into two times, and the damage to the mold is less than that of the single deformation, and secondly, the intermediate product rounded rectangular column can be used for subsequent cold heading stamping of the square part; At the same time, after the rough-machined bolt is obtained, the present invention only needs to open the first upper die core, close the second upper die core, and then cooperate with the punch to transform the portion between the cylindrical rod and the rounded rectangular column, and the rounded rectangular column into a square portion, and extrude the second compression hole and the portion in the first compression hole into a head in the sixth compression hole to obtain a plow-shaped bolt, and the plow-shaped bolt has good molding quality; When the plow-shaped bolt is cold headed, the present invention performs the cold heading on the same mold. The first upper mold core performs the cold heading first. After the first upper mold core is opened for cold heading, the lower mold core can be positioned by the clamping force. Then the second upper mold core can directly clamp the rounded rectangular column. Due to the existence of the rounded rectangular column, the four corners of the rounded rectangular column and the four sides of the seventh compression hole in the second upper mold core will not be squeezed. Instead, the four corners of the rounded rectangular column correspond to the four corners of the seventh compression hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0018] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a schematic diagram of the internal structure of the mold shell of the present invention; Figure 3 It is a schematic diagram of the connection between the rounded rectangular column and the first upper mold core of the present invention; Figure 4 It is a schematic diagram of the internal structure of the second upper mold core of the present invention; Figure 5 It is a schematic diagram of the connection between the plow-shaped bolt and the second upper mold core of the present invention; Figure 6 A schematic diagram of a rough-machined bolt according to the present invention; Figure 7 It is a schematic diagram of a plow-shaped bolt of the present invention; Figure 8 It is a schematic diagram of a sample corresponding to the plow-shaped bolt forming process of the present invention.

[0019] Description of reference numerals: 1. Wire to be processed; 2. Rounded rectangular column; 3. Cylindrical rod; 4. Square part; 5. Head; 6. Mould shell; 7. First slide groove; 8. Second slide groove; 9. First upper mould core; 901. First mould core; 902. Second mould core; 903. Third mould core; 904. Fourth mould core; 905. First compression hole; 906. Second compression hole; 907. Third compression hole; 908. Fourth compression hole; 10. Second upper mould core; 10a. Fifth mould core; 10b. Sixth mould core; 10c. Seventh mould core; 10d. Fifth compression hole; 10e. Sixth compression hole; 10f. Seventh compression hole; 11. Lower mould core; 11a. Lower mould core; 11b. Eighth compression hole; 12. Hydraulic assembly. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0021] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0022] The present invention provides Figure 1-8 A plow-shaped bolt forming process is shown, which is used to cold-forge and extrude the wire material 1 to be processed on the same die to form a plow-shaped bolt, and includes the following steps: S1: cold heading and stamping the wire material 1 to be processed, gradually constraining the four sides of the wire material 1 to be processed along the axial direction to form a rounded rectangular column 2, and when the rounded rectangular column 2 reaches a predetermined length, gradually constraining the four corners of the rounded rectangular column 2 along the axial direction to form a cylindrical rod 3 of a preset length, thereby obtaining a rough-machined bolt, wherein the diameter of the cylindrical rod 3 is smaller than the diameter of the wire material 1 to be processed; S2: The part of the die that contacts the cylindrical rod 3 remains unchanged, and the rest of the die is replaced to constrain the rough-machined bolts; S3: cold heading and stamping are performed on the rough-machined bolt, the portion where the rounded rectangular column 2 contacts the cylindrical rod 3 and the rounded rectangular column 2 are extruded and deformed into a square portion 4, and the portion where the rounded rectangular column 2 contacts the wire material 1 to be processed and the remaining portion of the wire material 1 to be processed are extruded and deformed into a head portion 5, thereby obtaining a plow-shaped bolt; S4: The part of the mold that contacts the cylindrical rod 3 remains unchanged, and the plow-shaped bolt is taken out when the rest of the mold is replaced; S5: After the rest of the die is replaced, the new wire material 1 to be processed is cold headed and stamped; In combination with a plow-shaped bolt forming process, the present invention further provides a plow-shaped bolt forming mold, including a mold shell 6, a first slide groove 7 and a second slide groove 8 opened in the mold shell 6, a first upper mold core 9 and a second upper mold core 10 slidably installed in the first slide groove 7 and the second slide groove 8, and a lower mold core 11 fixedly installed in the mold shell 6, the first upper mold core and the second upper mold core 10 can be half-separated for mold closing and mold opening, the first upper mold core 9 and the lower mold core 11 are molded to extrude the wire material 1 to be processed to form the rough-processed bolt, and the second upper mold core 10 and the lower mold core 11 are molded to extrude the rough-processed bolt to form a plow-shaped bolt; The present invention also provides a forming mold for a plow-shaped bolt, which is used in the forming process of the plow-shaped bolt, and includes a mold shell 6, in which a first slide groove 7 and a second slide groove 8 are intersecting and perpendicular to each other are opened, and the mold shell 6 is fixedly installed with a lower mold core 11a at the intersection of the first slide groove 7 and the second slide groove 8, and the lower mold core 11a has an eighth compression hole 11b in the lower mold core 11a, and the diameter and length of the eighth compression hole 11b are the same as those of the rod of the plow-shaped bolt, and the lower mold core 11a and the eighth compression hole 11b constitute a lower mold core 11 fixedly installed in the mold shell 6, The first upper mold core 9 and the second upper mold core 10 are slidably installed in the second slide groove 8 in the slide groove 7, respectively. The first upper mold core 9 and the second upper mold core 10 can be separated in half, close to each other for mold closing or away from each other in the first slide groove 7 or the second slide groove 8. In order to ensure the automation and stability during mold closing and opening, four hydraulic components 12 are installed on the mold shell 6. The output ends of two hydraulic components 12 are symmetrically installed on the first upper mold core 9, and the output ends of the other two hydraulic components 12 are symmetrically installed on the second upper mold core 10; The first upper die core 9 includes a first die core 901, a second die core 902, a third die core 903 and a fourth die core 904, wherein the four die cores respectively have a first compression hole 905, a second compression hole 906, a third compression hole 907 and a fourth compression hole 908 arranged coaxially. The diameter of the first compression hole 905 is the same as the diameter of the wire 1 to be processed, and the length is greater than the wire 1 to be processed, so as to ensure that the wire 1 to be processed will not be discharged from the first upper die core 9 during cold heading, stamping and forging. The shape of the third compression hole 907 is rounded. Rectangle, the length and width of this rounded rectangle are the same as the square part 4 of the plow-shaped bolt, but the four corners are rounded, the top cross-sectional shape of the second compression hole 906 is the same as the shape of the first compression hole 905, the bottom cross-sectional shape is the same as the shape of the third compression hole 907, and gradually transitions from a circle to a rounded rectangle from top to bottom, the top surface shape of the fourth compression hole 908 is the same as the shape of the third compression hole 907, the bottom cross-sectional shape is the same as the shape of the eighth compression hole 11b, and gradually transitions from a rounded rectangle to a circle from top to bottom; The second upper mold core 10 includes a fifth mold core 10a, a sixth mold core 10b and a seventh mold core 10c, wherein the three mold cores are respectively provided with a fifth compression hole 10d, a sixth compression hole 10e and a seventh compression hole 10f which are coaxially arranged. The fifth mold core 10a is circular in shape, and the diameter of the circle is the largest diameter of the plow-shaped bolt head 5. The shape of the seventh compression hole 10f is the same as that of the square portion 4. The shape of the sixth compression hole 10e is the same as that between the square portion 4 and the plow-shaped bolt head 5. The first upper mold core 9 and the second upper mold core 10 can be separated in half, and the vertical planes of the half separation are respectively the plane formed by the diagonal line of the third compression hole 907 and the plane formed by the seventh compression hole 10f; As for the common mature technologies in the prior art, such as ejector pins and punch heads, the ejector pins are located in the eighth compression hole 11b of the lower die core 11a, and there are two punch heads, one with the same diameter as the first compression hole 905, and the other with the same diameter as the fifth compression hole 10d; Cold heading stamping steps: At the beginning, the first upper mold core 9 is closed, and the second upper mold core 10 is opened. At this time, the bottom surface of the fourth mold core is tightly attached to the top surface of the lower mold core 11a. The wire material 1 to be processed is placed in the first compression hole 905, and then the punch head is used to press the wire material 1 to be processed into the lower mold core 11a. After the wire material 1 contacts with the second compression hole 906, it will gradually be constrained along the axial direction and squeezed toward the central axis by the four sides, and the length of the four sides gradually increases, forming an effect of constraining the four sides, until it enters the third compression hole 907 to form a complete rounded rectangular column 2. As the punch head continues to punch, the rounded rectangular column 2 will move into the fourth compression hole 908. After the rounded rectangular column 2 contacts the fourth compression hole 908, it will gradually be constrained along the axial direction and squeezed toward the central axis by the four corners. The four corners of the rounded rectangular column 2 will be gradually squeezed inward to form a cylindrical rod 3 inserted into the eighth compression hole 11b. When the length of the cylindrical rod 3 inserted into the eighth compression hole 11b reaches a predetermined length, a rough-machined bolt is obtained; Then the hydraulic assembly 12 first drives the first upper mold core 9 to separate in half to open the mold, and then drives the second upper mold core 10 to close the mold and re-clamp the rounded rectangular column 2 with the seventh compression hole 10f. At this time, the part squeezed by the third mold core 903 and the fourth mold core 904 is located in the seventh compression hole 10f, and the part compressed by the second compression hole 906 and the first compression hole 905 is located in the sixth compression hole 10e. At this time, a punch head with the same diameter as the fifth compression hole 10d is replaced to press the rough-machined bolt into the seventh compression hole 10f. The part located in the seventh compression hole 10f will be deformed, thereby occupying the space of the seventh compression hole 10f to form a square part 4, and the part in the sixth compression hole 10e will be deformed into a head 5; Afterwards, the hydraulic component 12 drives the second upper mold core 10 to separate in half and leave the mold a little. It is only necessary to ensure that the second upper mold core 10 no longer applies clamping force to the plow-shaped bolt, and use the ejector in the prior art to discharge the plow-shaped bolt from the eighth compression hole 11b, and the plow-shaped bolt is discharged from the fifth compression hole 10d. Then, the second upper mold core 10 is completely opened and the first upper mold core 9 is closed.

[0023] It is important to note that the construction and arrangement of the present application shown in a number of different exemplary embodiments are exemplary only. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible (e.g., the size, scale, structure, shape and proportion of various elements, and parameter values ​​(e.g., temperature, pressure, etc.), mounting arrangements, use of materials, colors, changes in orientation, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in this application.

Claims

1. A plow-shaped bolt forming process, for cold heading and extruding a wire material (1) to be processed on the same die to form a plow-shaped bolt, characterized in that: The following steps are involved: S1: cold heading and stamping the wire material (1) to be processed, gradually constraining the four sides of a portion of the wire material (1) to be processed along the axial direction to form a rounded rectangular column (2), and when the rounded rectangular column (2) reaches a predetermined length, gradually constraining the four corners of a portion of the rounded rectangular column (2) along the axial direction to form a cylindrical rod (3) of a preset length, thereby obtaining a rough-machined bolt, wherein the diameter of the cylindrical rod (3) is smaller than the diameter of the wire material (1) to be processed; S2: The part of the die that contacts the cylindrical rod (3) remains unchanged, and the rest of the die is replaced to constrain the rough-machined bolts; S3: cold heading and stamping the rough-machined bolt, the portion where the rounded rectangular column (2) contacts the cylindrical rod (3), and the rounded rectangular column (2) are extruded and deformed into a square portion (4), and the portion where the rounded rectangular column (2) contacts the wire material to be processed (1), and the remaining portion of the wire material to be processed (1) are extruded and deformed into a head portion (5), thereby obtaining a plow-shaped bolt; S4: The part of the mold that contacts the cylindrical rod (3) remains unchanged, and the plow bolt is removed when the remaining part is replaced; S5: After the rest of the die is replaced, the new wire material (1) to be processed is subjected to cold heading.

2. A plow-shaped bolt forming die, applied to the plow-shaped bolt forming die according to claim 1, characterized in that: The mold shell (6) comprises a mold shell (6), a first slide groove (7) and a second slide groove (8) provided in the mold shell (6), a first upper mold core (9) and a second upper mold core (10) slidably installed in the first slide groove (7) and the second slide groove (8), and a lower mold core (11) fixedly installed in the mold shell (6). The first upper mold core and the second upper mold core (10) can be half-separated for mold closing and mold opening. When the first upper mold core (9) and the lower mold core (11) are closed, they extrude the wire material to be processed (1) to form the rough-processed bolt. When the second upper mold core (10) and the lower mold core (11) are closed, they extrude the rough-processed bolt to form a plow-shaped bolt.

3. A plow-shaped bolt forming die according to claim 2, characterized in that: The first upper mold core (9) comprises a first mold core (901) for accommodating the wire material (1) to be processed for guiding, a second mold core (902) for extruding a portion of the wire material (1) to be processed to form a rounded rectangular column (2), a third mold core (903) for obtaining a rounded rectangular column (2) of a predetermined length, and a fourth mold core (904) for extruding a portion of the rounded rectangular column (2) to form a cylindrical rod (3), wherein the first mold core (901), the second mold core (902), the third mold core (903) and the fourth mold core (904) respectively have a first compression hole (905), a second compression hole (906), a third compression hole (907) and a fourth compression hole (908) coaxially arranged therein.

4. A plow-shaped bolt forming die according to claim 3, characterized in that: The second upper mold core (10) comprises a fifth mold core (10a) for accommodating the rough-machined bolt, a sixth mold core (10b) for extruding to form the head (5), and a seventh mold core (10c) for extruding to form the square portion (4). The fifth mold core (10a), the sixth mold core (10b) and the seventh mold core (10c) respectively have a coaxially arranged fifth compression hole (10d), a sixth compression hole (10e) and a seventh compression hole (10f). The seventh mold core (10c) and the fourth mold core (904) are respectively slidably connected to the first slide groove (7) and the second slide groove (8).

5. The plow-shaped bolt forming die according to claim 4, characterized in that: The rounded rectangle formed by the third compression hole (907) and the seventh compression hole (10f) on the horizontal plane has the same length and width, and the rounded corner radius of the third compression hole (907) is greater than the rounded corner radius of the seventh compression hole (10f).

6. The plow-shaped bolt forming die according to claim 5, characterized in that: The top surface of the second compression hole (906) is a circle having the same shape as the horizontal cross section of the first compression hole (905), the bottom surface of the second compression hole (906) and the top surface of the fourth compression hole (908) are both rounded rectangles having the same shape as the horizontal cross section of the third compression hole (907), and the bottom surface of the fourth compression hole (908) is a circle having a diameter the same as the width of the rounded rectangle.

7. The plow-shaped bolt forming die according to claim 6, characterized in that: The lower mold core (11) comprises a lower mold core (11a) fixedly mounted in the mold shell (6), wherein the lower mold core (11a) has an eighth compression hole (11b), and the diameter of the eighth compression hole (11b) is the same as the bottom diameter of the fourth compression hole (908).

8. The plow-shaped bolt forming die according to claim 6, characterized in that: The diameter of the fifth compression hole (10d) is greater than the diameter of the first compression hole (905), and the diameter of the first compression hole (905) is greater than the diameter of the eighth compression hole (11b).

9. The plow-shaped bolt forming die according to claim 6, characterized in that: When the mold is opened, the first upper mold core (9) is separated into two halves with the diagonal line of the third compression hole (907) as the center line, and when the mold is opened, the second upper mold core (10) is separated into two halves with the diagonal line of the seventh compression hole (10f) as the center line.

10. The plow-shaped bolt forming die according to claim 1, characterized in that: Four hydraulic assemblies (12) are mounted on the mold shell (6), the output ends of two hydraulic assemblies (12) are symmetrically mounted on the first upper mold core (9), and the output ends of the other two hydraulic assemblies (12) are symmetrically mounted on the second upper mold core (10).

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