Connecting rod screw cold heading die

Abstract

The utility model discloses a connecting rod screw cold heading die, which relates to the field of screw cold heading processing and comprises a first die, a second die and a third die which are sequentially arranged. One end of the blank is subjected to diameter shrinkage and upset by the first die to form a first pre-upset rod, and the other end of the blank is subjected to strong beam extrusion by the first die to form a first spherical table and a circular table so as to form a first die blank; the second die expands the diameter of the first pre-upsetting rod and upsets the first pre-upsetting rod into a second pre-upsetting rod, and the second die forcibly extrudes the circular truncated cone to form a second spherical table so as to form a second die blank. And the third die extrudes the second ball table and the third ball table in a strong beam mode to form a ball head, and a product to be subjected to thread rolling is formed. And upsetting the blank end into a big-end-up ball head rough blank, carrying out step-by-step multi-time cold upsetting expanding forming on the ball head rough blank, and forming the ball head step by step. The deformation in each step is smaller, the deformation is controlled, the situation that the surface size of a product does not conform to form and location tolerance is avoided, and it is guaranteed that the forming precision requirement is met.

Description

TECHNICAL FIELD

[0001] The utility model relates to screw cold heading processing field especially a connecting rod screw cold heading die. BACKGROUND

[0002] Cold heading is a kind of forging method that uses die to upset (usually partial upset) metal bar stock at room temperature.Forming the head of screw, bolt, rivet, etc.Can reduce or replace cutting processing.

[0003] As Figure 6 The connecting rod screw includes ball head, first rod, second rod and third rod connected in sequence, the ball head is spherical platform, the ball head and first rod are chamfered, the first rod and second rod are chamfered, and hexagonal groove is arranged at the center position of the end face of the third rod away from the second rod.Cold heading processing, the external thread is processed by thread rolling on the circumferential surface of the third rod.

[0004] During cold heading, the ball is formed at one end of the blank, and the other end of the ball is upset to form the shape of the ball head.During forming, half of the ball head is located inside the punch, and the other half of the ball head is located inside the main die.Limited by the size tolerance of the main die and the punch, a gap will inevitably exist between the main die and the punch when they are combined.During cold heading, the ball head deforms, and part of the blank is formed in the gap between the main die and the punch, resulting in traces on the spherical surface of the ball head, affecting the accuracy of the ball head.

[0005] Therefore, the utility model aims at providing a connecting rod screw cold heading die to solve the problem of uncontrollable deformation during cold heading of the ball head. UTILITY MODEL CONTENTS

[0006] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a connecting rod screw cold heading die, the connecting rod screw cold heading die includes ball head, first rod, second rod and third rod connected in sequence, the ball head is spherical platform, the diameter D1 of the upper bottom surface of the spherical platform is less than the diameter L2 of the second rod, the diameter L1 of the first rod is equal to the diameter L3 of the third rod, and the diameter D2 of the ball head is less than the diameter of the first rod, the ball head and the first rod are chamfered, the first rod and the second rod are chamfered, and hexagonal groove is arranged at the center position of the end face of the third rod away from the second rod, the connecting rod screw cold heading die includes one die, two die and three die arranged in sequence.

[0007] The first die shrinks the diameter of one end of the blank to form a first pre-header, the first die extrudes the other end of the blank to form a first ball table and a circular table, the lower bottom surfaces of the first ball table and the circular table are connected to each other, the first ball table, the circular table and the first pre-header are connected in sequence, the middle part of the first pre-header is extruded to form a first inclined angle, the side surface of the circular table is an outward convex circular arc surface, forming a first die blank, and the diameter of the lower bottom surface of the circular table is smaller than that of the lower bottom surface of the first ball table.

[0008] The second die expands the diameter of the first pre-header to form a second pre-header, the second die extrudes the circular table to form a second ball table, the second die increases the height of the first ball table to form a third ball table, and the second die extrudes the first inclined angle towards the circular table to form a second inclined angle, forming a second die blank, and the diameter of the lower bottom surface of the second ball table is smaller than that of the lower bottom surface of the third ball table.

[0009] The third die extrudes the second ball table and the third ball table to form a ball head, the third die thickens the end of the second pre-header close to the circular table to form a second rod, the third die thickens the end of the second pre-header away from the circular table to form a third rod, and a hexagonal recess is formed in the center of the end surface of the third rod away from the second rod, forming a product to be threaded.

[0010] Preferably, the first die includes a first main die and a first punch, the first punch includes a first punch head, a first insert and a first insert pin, the first insert is embedded in the first punch head, a first punch cavity is formed in the center of the first punch head, the first insert pin is embedded in the end of the first punch cavity away from the first main die, and the end of the first punch cavity close to the first main die is in the shape of a circular table.

[0011] Preferably, the first main die includes a first die shell and a first die core, the first die core is embedded in one end of the first die shell, a first main die cavity is formed in the center of the first die core, and a circular table-shaped first cavity is arranged at the end of the first main die cavity close to the first punch.

[0012] Preferably, the second die includes a second main die and a second punch, the second punch includes a second punch head, a second insert and a second insert pin, the second punch head is provided with a second punch cavity at one end, the second insert is embedded in the other end of the second punch head, the second insert pin is embedded in the second punch head, one end of the second insert pin is arranged at the end of the second punch cavity away from the second main die, the other end of the second insert pin is detachably arranged in the second insert, the second punch cavity is in the shape of a hemisphere, the first platform is arranged at the end of the second insert pin close to the second main die, and the edge of the first platform is in abutment with the inner wall of the second punch cavity.

[0013] Preferably, the second main mold comprises a second mold shell and a second mold core, the second mold core is embedded in one end of the second mold shell, a second main mold cavity is arranged in the center of the second mold core, and a spherical platform-shaped second cavity is arranged at one end of the second main mold cavity close to the second punch, the spherical center of the second cavity is arranged at one side of the second main mold cavity close to the second punch, and the diameter of the second cavity is smaller than the diameter of the second punch cavity.

[0014] Preferably, the third mold comprises a third main mold and a third punch, the third main mold comprises a third mold shell, a third mold core, a third insert, a guide block, a needle, a sleeve and a rear pad, the third insert, the guide block, the sleeve and the rear pad are coaxially arranged in sequence, the third insert and the guide block are respectively embedded in the center of the opposite end faces of the third mold core, the sleeve and the rear pad are slidingly arranged in the inside of the third mold shell, the third insert is provided with a third main mold cavity in the center thereof, a spherical platform-shaped third cavity is arranged at one end of the third main mold cavity close to the third punch, a guide hole communicating with the third main mold cavity is arranged in the center of the guide block, one end of the needle is embedded in the rear pad, the other end of the needle is arranged in the center of the sleeve, a punch shaped as a regular hexagonal prism is arranged at the end of the needle away from the rear pad, and the diameter of the guide hole is equal to the diameter of the third rod. The diameter of the middle part of the third main mold cavity is smaller than the diameters of the two ends of the third main mold cavity.

[0015] Further, the third insert comprises a first column and a second column, the first column and the second column are symmetrically arranged, the first column and the second column are respectively provided with a positioning block and a positioning groove, and the positioning blocks are arranged in the positioning grooves one by one.

[0016] Preferably, the third punch comprises a third punch, a third insert and a third insert needle, one end of the third punch is provided with a third punch cavity, the third insert is detachably arranged at the other end of the third punch, the third insert needle is arranged in the third punch, one end of the third insert needle is arranged at the end of the third punch cavity away from the third main mold, and the other end of the third insert needle is detachably arranged in the center of the third insert. The third punch cavity is semispherical, the end of the third insert needle close to the third main mold is provided with a second platform, the edge of the second platform abuts against the inner wall of the third punch cavity, and the area of the second platform is smaller than the area of the first platform.

[0017] Preferably, the second insert needle and the third insert needle are both composed of a needle body and a spherical segment, the needle body and the spherical segment are integrally connected, and the bottom surface of the spherical segment forms the first platform or the second platform.

[0018] Preferably, the sleeve is composed of a tube body and a disc body, the disc body is arranged at one end of the tube body close to the rear pad, the diameter of the guide block is smaller than the diameter of the disc body, and the outer diameter of the tube body is smaller than or equal to the diameter of the guide hole.

[0019] Preferably, the third main mold further includes a first ejector rod and a second ejector rod, both of which are movably disposed on the side of the rear pad away from the third die. The first ejector rod is projected onto the center of the rear pad along the mold closing direction, and the second ejector rod is projected onto the disc body along the mold closing direction. The rear pad has a through hole for the second ejector rod to pass through.

[0020] The beneficial effects of this invention are as follows: A ball-shaped blank with a larger upper end and a smaller lower end is formed by upsetting the blank end, and then the ball-shaped blank is cold-forged and expanded in multiple steps to form the ball head. This minimizes the deformation at each step, controls the deformation amount to avoid the product surface dimensions not meeting the geometric tolerances, and ensures that the forming accuracy requirements are met. Attached Figure Description

[0021] The accompanying drawings further illustrate the present invention, but the embodiments in the drawings do not constitute any limitation on the present invention.

[0022] Figure 1 This is a schematic diagram of the structure of a cold heading die for connecting rod screws provided in an embodiment of the present invention;

[0023] Figure 2 A schematic diagram illustrating the forming of a connecting rod screw according to an embodiment of this utility model;

[0024] Figure 3 This is a schematic diagram of the structure of the second insert provided in an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the structure of a push pin provided in an embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of the structure of the rear pad provided in an embodiment of the present utility model;

[0027] Figure 6 This is a schematic diagram of the connecting rod screw provided in an embodiment of the present invention;

[0028] Reference numerals: 111: First mold shell; 112: First mold core; 121: First punch; 122: First insert; 123: First insert pin; 211: Second mold shell; 212: Second mold core; 221: Second punch; 222: Second insert; 223: Second insert pin; 311: Third mold shell; 312: Third mold core; 313: Third insert; 314: Guide block; 315: Ejector pin; 316: Sleeve; 317: Back pad; 321: Third punch; 322: Third insert; 323: Third insert pin; 41: First ball table; 42: Frustum; 43: First pre-upsetting rod; 44: First angle; 51: Third ball table; 52: Second ball table; 53: Second pre-upsetting rod; 54: Second angle; 61: Ball head; 62: First rod; 63: Second rod; 64: Third rod. Detailed Implementation

[0029] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of this utility model.

[0030] It should be noted that, in this utility model, unless otherwise stated, when an element is referred to as "fixed to" or "set on" another element, it can be directly on the other element or may have an intervening element present simultaneously. "The lower surface of the table tennis table" refers to the largest bottom surface of the table tennis table. "Far" and "near" refer to distance relative to a certain component.

[0031] like Figures 1-5 As shown in the figure, an embodiment of the present invention provides a cold heading mold for connecting rod screws. The cold heading of the connecting rod screw includes a ball head 61, a first rod 62, a second rod 63, and a third rod 64 connected in sequence. The ball head 61 is a ball table. The diameter D1 of the upper bottom surface of the ball table is less than the diameter L2 of the second rod 63, less than the diameter L1 of the first rod 62, equal to the diameter L3 of the third rod 64, and less than the diameter D2 of the ball head 61. The ball head 61 and the first rod 62 are rounded, and the first rod 62 and the second rod 63 are chamfered. A hexagonal groove is provided at the center of the end face of the third rod 64 away from the second rod 63. The cold heading mold for connecting rod screws includes a first mold, a second mold, and a third mold arranged in sequence.

[0032] The first die shrinks one end of the blank to form a first pre-upsetting rod 43, and the other end of the blank is strongly compressed to form a first spherical frustum 41 and a truncated cone 42. The lower surfaces of the first spherical frustum 41 and the truncated cone 42 are connected to each other. The first spherical frustum 41, the truncated cone 42 and the first pre-upsetting rod 43 are connected in sequence. The middle part of the first pre-upsetting rod 43 is strongly compressed to form a first oblique angle 44. The side of the truncated cone 42 is an outwardly convex arc surface to form a first die blank. The diameter of the lower surface of the truncated cone 42 is smaller than the diameter of the lower surface of the first spherical frustum 41. During cold upsetting, the edges of the truncated cone 42 are all contained inside the lower surface of the first spherical frustum 41, and the overflowing blank is also located inside the lower surface of the first spherical frustum 41 to avoid the overflow of blank affecting the spherical accuracy.

[0033] The second mold expands the diameter of the first pre-upsetting rod 43 to form the second pre-upsetting rod 53. The second mold strongly compresses the frustum 42 to form the second spherical platform 52. The second mold upsets the first spherical platform 41 to form the third spherical platform 51. The second mold strongly compresses the first oblique angle 44 toward the frustum 42 to form the second oblique angle 54, forming the second mold blank. The diameter of the lower bottom surface of the second spherical platform 52 is smaller than the diameter of the lower bottom surface of the third spherical platform 51. During cold upsetting, the edges of the second spherical platform 52 are all contained inside the lower bottom surface of the third spherical platform 51. The overflowing blank will be located at the edge of the third spherical platform 51 to avoid the blank overflow affecting the spherical accuracy.

[0034] The three dies extrude the second ball table 52 and the third ball table 51 to form the ball head 61, the three dies upset the second pre-upset rod 53 at one end close to the circular table 42 to form the second rod 63, the three dies upset the second pre-upset rod 53 at one end away from the circular table 42 to form the third rod 64, and at the same time, a hexagonal recess is upset at the center of the end face of the third rod 64 away from the second rod 63 to form the product to be threaded. The size of the second ball table 52 and the third ball table 51 is approximately equal to the ball head 61, which reduces the deformation and stress, and avoids extruding the blank to the spherical surface.

[0035] The first die includes a first main die and a first punch die, the first punch die includes a first punch 121, a first insert 122 and a first insert pin 123, the first insert 122 is embedded in the first punch 121, a first punch die cavity is formed in the center of the first punch 121, the first insert pin 123 is embedded in the first punch die cavity away from the first main die, and the end of the first punch die cavity close to the first main die is in the shape of a ball table.

[0036] The first main die includes a first die shell 111 and a first die core 112, the first die core 112 is embedded in one end of the first die shell 111, a first main die cavity is formed in the center of the first die core 112, and a first cavity in the shape of a circular table 42 is arranged at the end of the first main die cavity close to the first punch die.

[0037] The second die includes a second main die and a second punch die, the second punch die includes a second punch 221, a second insert 222 and a second insert pin 223, the second punch 221 is provided with a second punch die cavity at one end, the second insert 222 is embedded in the other end of the second punch 221, the second insert pin 223 is embedded in the second punch 221, one end of the second insert pin 223 is arranged at the end of the second punch die cavity away from the second main die, and the other end of the second insert pin 223 is detachably arranged in the second insert 222, the second punch die cavity is in the shape of a hemisphere, the first platform is arranged at the end of the second insert pin 223 close to the second main die, and the edge of the first platform is in abutment with the inner wall of the second punch die cavity.

[0038] The second main die includes a second die shell 211 and a second die core 212, the second die core 212 is embedded in one end of the second die shell 211, a second main die cavity is formed in the center of the second die core 212, a second cavity in the shape of a ball table is arranged at the end of the second main die cavity close to the second punch die, the spherical center of the second cavity is arranged at the side of the second main die cavity close to the second punch die, and the diameter of the second cavity is smaller than the diameter of the second punch die cavity.

[0039] The third die includes a third punch, a third insert block and a third insert pin, the third punch is provided with a third die cavity at one end, the third insert block is detachably arranged at the other end of the third punch, and the third insert pin is arranged in the third punch, one end of the third insert pin is arranged at the end of the third die cavity away from the third die, and the other end of the third insert pin is detachably arranged at the center position of the third insert block, the third die cavity is in a semispherical shape, one end of the third insert pin close to the third die is provided with a second platform, the second platform is in abutment with the inner wall of the third die cavity at the edge position, and the area of the second platform is smaller than that of the first platform.

[0040] The third die includes a third punch, a third insert block and a third insert pin, the third punch is provided with a third die cavity at one end, the third insert block is detachably arranged at the other end of the third punch, and the third insert pin is arranged in the third punch, one end of the third insert pin is arranged at the end of the third die cavity away from the third die, and the other end of the third insert pin is detachably arranged at the center position of the third insert block, the third die cavity is in a semispherical shape, one end of the third insert pin close to the third die is provided with a second platform, the second platform is in abutment with the inner wall of the third die cavity at the edge position, and the area of the second platform is smaller than that of the first platform.

[0041] The second insert pin 223 and the third insert pin 323 are both composed of a needle body and a spherical segment, and the needle body and the spherical segment are integrally connected.

[0042] The sleeve 316 is composed of a tube body and a disc body, the disc body is arranged at one end of the tube body close to the back pad 317, the diameter of the guide block 314 is smaller than that of the disc body, and the outer diameter of the tube body is smaller than or equal to the diameter of the guide hole.

[0043] The third die further includes a first ejector rod and a second ejector rod, the first ejector rod and the second ejector rod are movably arranged on the side of the back pad 317 away from the third die, the first ejector rod is projected on the center position of the back pad 317 in the closing direction, the second ejector rod is projected on the disc body in the closing direction, and the back pad 317 is provided with a through hole for the second ejector rod to penetrate.

[0044] Compared with the above embodiment, the third insert 313 of the embodiment comprises a first column body and a second column body, the first column body and the second column body are symmetrically arranged, the first column body and the second column body are respectively provided with a positioning block and a positioning groove, and the positioning block is arranged in the positioning groove in one-to-one correspondence.

[0045] The technical features of the above-mentioned embodiments can be combined arbitrarily, and in order to make the description simple, all possible combinations of the technical features in the above-mentioned embodiments are not described. It should be pointed out that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which should be considered as the scope of the present application.

Claims

1. A connecting rod screw cold heading die characterized by: The connecting rod screw comprises a ball head, a first rod, a second rod and a third rod connected in sequence, the ball head is a spherical platform, the ball head and the first rod are chamfered, the first rod and the second rod are bevelled, the third rod is provided with a hexagonal groove at the center position of the end surface away from the second rod, and the connecting rod screw cold heading die comprises a first die, a second die and a third die arranged in sequence. The first die reduces the diameter of one end of the blank to form a first pre-heading rod, the other end of the blank is strongly extruded to form a first spherical platform and a circular platform, the lower bottom surfaces of the first spherical platform and the circular platform are connected to each other, the first spherical platform, the circular platform and the first pre-heading rod are connected in sequence, the middle part of the first pre-heading rod is strongly extruded to form a first bevel, the side surface of the circular platform is an outward convex circular surface to form a first die blank, and the diameter of the lower bottom surface of the circular platform is smaller than that of the first spherical platform. The second die expands the diameter of the first pre-heading rod to form a second pre-heading rod, the circular platform is strongly extruded to form a second spherical platform, the first spherical platform is headed to form a third spherical platform, the first bevel is strongly extruded towards the circular platform to form a second bevel, and a second die blank is formed, the diameter of the lower bottom surface of the second spherical platform is smaller than that of the third spherical platform. The third die strongly extrudes the second spherical platform and the third spherical platform to form a ball head, the second pre-heading rod is thickened at the end close to the circular platform to form a second rod, the second pre-heading rod is thickened at the end away from the circular platform to form a third rod, and a hexagonal groove is formed at the center position of the end surface of the third rod away from the second rod, thereby forming a product to be threaded.

2. A connecting rod screw cold heading die according to claim 1, characterized in that: The first die comprises a first main die and a first punch, the first punch comprises a first punch head, a first insert and a first insert pin, the first insert is embedded in the first punch head, a first punch cavity is formed at the center position of the first punch head, the first insert pin is embedded in the first punch cavity away from the first main die, and the first punch cavity close to the first main die is in the shape of a spherical platform.

3. A connecting rod screw cold heading die according to claim 2, characterized in that: The first main die comprises a first die shell and a first die core, the first die core is embedded in one end of the first die shell, a first main die cavity is formed at the center position of the first die core, and the first main die cavity close to the first punch is in the shape of a circular platform.

4. The connecting rod screw cold heading die according to claim 1, characterized in that: The second die comprises a second main die and a second punch, the second punch comprises a second punch head, a second insert and a second insert pin, the second punch head is provided with a second punch cavity at one end, the second insert is embedded in the other end of the second punch head, the second insert pin is embedded in the second punch head, one end of the second insert pin is arranged at the end of the second punch cavity away from the second main die, and the other end of the second insert pin is detachably arranged in the second insert, the second punch cavity is in the shape of a hemisphere, the first platform is arranged at the end of the second insert pin close to the second main die, and the edge of the first platform is in abutment with the inner wall of the second punch cavity.

5. A connecting rod screw cold heading die according to claim 4, characterized in that: The second main die comprises a second die shell and a second die core, the second die core is embedded in one end of the second die shell, a second main die cavity is formed at the center position of the second die core, and the second main die cavity close to the second punch is provided with a second cavity in the shape of a spherical platform, the spherical center of the second cavity is arranged at the side of the second main die cavity close to the second punch, and the diameter of the second cavity is smaller than that of the second punch cavity.

6. The connecting rod screw cold heading die according to claim 4, characterized in that: The third die includes a third punch, a third insert block and a third insert needle, one end of the third punch is provided with a third die cavity, the third insert block is detachably arranged at the other end of the third punch, the third insert needle is arranged in the third punch, one end of the third insert needle is arranged at the end of the third die cavity away from the third main die, the other end of the third insert needle is detachably arranged at the center of the third insert block, the third die cavity is semispherical, one end of the third insert needle away from the third main die is provided with a second platform, the second platform is in abutment with the inner wall of the third die cavity at the edge position, and the area of the second platform is smaller than that of the first platform.

7. A connecting rod screw cold heading die according to claim 6, characterized in that: The second insert needle and the third insert needle are both composed of a needle body and a spherical segment, the needle body and the spherical segment are integrally connected, and the bottom surface of the spherical segment forms a first platform or a second platform.

8. A connecting rod screw cold heading die according to claim 7, characterized in that: The sleeve is composed of a tube body and a disc body, the disc body is arranged at one end of the tube body close to the back pad, the diameter of the guide block is smaller than the diameter of the disc body, and the outer diameter of the tube body is smaller than or equal to the diameter of the guide hole.

9. The connecting rod screw cold heading die according to claim 6, characterized in that: Further comprising a first ejector rod and a second ejector rod, the first ejector rod and the second ejector rod are both movably arranged on the side of the back pad away from the third die, the first ejector rod is projected on the center of the back pad in the direction of clamping, the second ejector rod is projected on the disc body in the direction of clamping, and the back pad is provided with a through hole for the second ejector rod to penetrate.

10. The connecting rod screw cold heading die according to claim 6, characterized in that: ​

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