Special-shaped double-head connecting piece and cold heading forming die thereof

Abstract

The utility model relates to the field of machining, and discloses a special-shaped double-head connecting piece and a cold heading forming die thereof, the connecting piece is composed of a first connecting head, a second connecting head and a positioning shaft shoulder located between the first connecting head and the second connecting head; the cross section of the first connector and the cross section of the second connector are non-full-circle special-shaped faces. The connecting piece is formed on a multi-station forming machine in a cold heading mode through a cold heading forming die. According to the special-shaped double-head connecting piece, the two connecting heads are designed to be special-shaped columns, so that after the two connecting pieces are connected, the good anti-torque effect is achieved, and the possible problem of connection failure caused by torque can be effectively solved; meanwhile, a cold heading forming die can be directly adopted for direct cold heading forming, the product precision is high, additional machining procedures are not needed, and the machining cost can be effectively reduced.

Description

Technical Field

[0001] The utility model relates to the field of machining, in particular to a special-shaped double-head connecting piece and a cold heading forming die thereof. Background Art

[0002] Double-ended connectors are used to connect two components, and usually use interference fit to connect the two components. However, the two end connectors of current double-ended connectors are usually cylindrical. The cylindrical connectors are easy to process, but if there is torsion between the two components, the connection strength between the two components will be seriously affected. Therefore, the present application designs a special-shaped double-ended connector, which has the function of resisting torque and can improve the connection strength between the two components.

[0003] At present, the existing processing method for special-shaped connectors is mainly to first cold-forge the semi-finished product, and then machine it to obtain a rough blank. This processing method requires a machining program, which consumes a large amount of material and manpower. At the same time, due to the characteristics of machining, the utilization rate of materials is also greatly reduced, increasing material costs. Therefore, this application designs a set of cold forging molds to directly cold-forge a rough blank, eliminating the machining process. Utility Model Content

[0004] The utility model aims to solve the technical problems existing in the prior art. To this end, the utility model provides a special-shaped double-head connector and a cold heading forming die thereof.

[0005] The technical solution adopted by the utility model to solve its technical problems is:

[0006] In the first aspect, a special-shaped double-head connector is provided, which is composed of a first connector, a second connector and a positioning shoulder located between the first connector and the second connector; the cross-sections of the first connector and the second connector are non-circular special-shaped surfaces; the connector is cold-forged by a cold-forging die on a multi-station forming machine.

[0007] Preferably, the first connector is a columnar body composed of a plane, a curved surface, a first inclined surface and a second inclined surface, and the two connected surfaces are connected by a chamfered transition; the second connector is a columnar body composed of a plane and a curved surface, wherein the arc forming the curved surface is a major arc, and the plane and the curved surface are connected by a chamfered transition.

[0008] Preferably, the plane of the first connector and the plane of the second connector are misaligned or opposite in orientation.

[0009] Preferably, the heat treatment hardness of the connecting piece reaches 420-490 HV, and the surface is Magnetic treated.

[0010] Preferably, a positioning surface is provided on the positioning shoulder for positioning during installation.

[0011] In a second aspect, a cold heading forming die is provided for processing the special-shaped double-head connector, comprising:

[0012] Four groups of positive molds, including a one-sequence positive mold, a two-sequence positive mold, a three-sequence positive mold and a four-sequence positive mold;

[0013] Four groups of negative molds, including a first-order negative mold, a second-order negative mold, a third-order negative mold, and a fourth-order negative mold corresponding to the first-order positive mold, the second-order positive mold, the third-order positive mold, and the fourth-order positive mold respectively;

[0014] The four groups of male and female molds are respectively installed on the multi-station forming machine. The blank is moved between the four groups of male and female molds through the clamping system of the forming machine, and the blank is sequentially processed by head expansion and tail preforming, head preforming, head and tail forming, and trimming.

[0015] Preferably, the first-order positive mold comprises:

[0016] A first-order male die punch sleeve, fixedly installed on the molding machine;

[0017] A first-order male die ejector pin, which moves through and exposes the male die punch sleeve, is used for punching the blank;

[0018] A first-order male mold pad is arranged in the male mold punch sleeve and is used to limit the male mold ejector rod;

[0019] The first-order negative mold comprises:

[0020] A first-order female die sleeve is installed on the molding machine opposite to a first-order male die sleeve;

[0021] A first-order expansion rod mold core is embedded in the end of a first-order female mold sleeve, and a cavity for expanding the head of the blank and preforming the tail is provided in the first-order expansion rod mold core;

[0022] The first-order female mold ejector rod penetrates the first-order female mold sleeve and extends into the cavity of the first-order expansion rod mold core, and is used for pushing out the blank and shaping the tail of the blank.

[0023] Preferably, the second-order positive mold comprises:

[0024] A second-order male die punch sleeve is fixedly installed on the molding machine;

[0025] A second-order male mold core is embedded in the end of the second-order male mold punch sleeve, and a cavity for the head of the preform blank is provided in the second-order male mold core;

[0026] The second-order male mold ejector rod is movably arranged in the second-order male mold punch sleeve, and one end of the ejector rod extends into the cavity of the second-order male mold core, and is used for shaping the head of the blank;

[0027] The second-order male mold cushion block is arranged in the second-order male mold punch sleeve and is used to limit the second-order male mold ejector rod;

[0028] The two-order negative mold comprises:

[0029] A second-order female die sleeve is installed on the molding machine relative to the second-order male die sleeve;

[0030] A second-order straight-through mold core is embedded in the end of the second-order female mold sleeve relative to the second-order male mold core, and a cavity for constraining the tail of the blank is provided in the second-order straight-through mold core;

[0031] The second-order female mold ejector rod passes through the second-order female mold sleeve and extends into the cavity of the second-order straight-through mold core, and is used to push out the blank and shape the tail of the blank.

[0032] Preferably, the three-sequence positive mold comprises:

[0033] A three-stage male die punch sleeve, fixedly mounted on the molding machine;

[0034] A three-sequence male die core is embedded in the end of the three-sequence male die punch sleeve, and a cavity for molding the head of the blank is provided in the three-sequence male die core;

[0035] The three-sequence male die ejector rod is movably arranged in the three-sequence male die punch sleeve, and one end of the ejector rod extends into the cavity of the three-sequence male die core, and is used for shaping the head of the blank;

[0036] The three-sequence male mold pad is arranged in the three-sequence male mold punch sleeve and is used to limit the three-sequence male mold ejector rod;

[0037] The three-order negative mold comprises:

[0038] A three-sequence female die sleeve is installed on the molding machine relative to the three-sequence male die sleeve;

[0039] A three-sequence straight-through mold core is embedded in the end of the three-sequence female mold sleeve relative to the three-sequence male mold core, and a cavity for constraining the tail of the blank is provided in the three-sequence straight-through mold core;

[0040] The three-stage female mold ejector rod passes through the three-stage female mold sleeve and extends into the cavity of the three-stage straight-through mold core, and is used for pushing out the blank and shaping the tail of the blank.

[0041] Preferably, the four-sequence positive mold includes:

[0042] Four-sequence male die punch sleeve, fixedly installed on the molding machine;

[0043] The trimming die is annular, and its inner cavity can accommodate the head of the blank. The trimming die is embedded in the four-sequence male die punch sleeve and is used to cut out the positioning shoulder of the blank head;

[0044] The four-order negative mold includes:

[0045] A four-sequence female die sleeve is installed on the molding machine relative to the four-sequence male die punch sleeve;

[0046] A four-sequence straight-through mold core is embedded in the end of the four-sequence female mold sleeve relative to the trimming mold, and a cavity for constraining the tail of the blank is provided in the four-sequence straight-through mold core;

[0047] The ejector rod of the four-sequence female mold passes through the four-sequence female mold sleeve and extends into the cavity of the four-sequence straight-through mold core, and is used to push out the blank and shape the tail of the blank.

[0048] Compared with the prior art, the beneficial effects of the utility model are:

[0049] The special-shaped double-head connector designed by the utility model has two connecting heads designed as special-shaped columns, so that after the two connecting parts are connected, they have good anti-torque effect, which can effectively solve the problem of connection failure that may be caused by torque; at the same time, they can be directly cold-forging by a cold-forging forming die, the product has high precision, does not require additional machining steps, and can effectively reduce processing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0051] Figure 1 It is a mold closing state diagram of a first-order positive mold and a first-order negative mold provided by the utility model;

[0052] Figure 2 yes Figure 1 The blank forming diagram provided;

[0053] Figure 3 yes Figure 2 Provide a right side view of the blank;

[0054] Figure 4 It is a mold closing state diagram of a two-sequence male mold and a two-sequence female mold provided by the utility model;

[0055] Figure 5 yes Figure 4 The blank forming diagram provided;

[0056] Figure 6 yes Figure 5 A left side view of the blank is provided;

[0057] Figure 7 yes Figure 5 A right side view of the blank is provided;

[0058] Figure 8 It is a mold closing state diagram of the three-sequence male mold and the three-sequence female mold provided by the utility model;

[0059] Fig. 9 yes Figure 8 The blank forming diagram provided;

[0060] Fig.10 yes Fig. 9 A left side view of the blank is provided;

[0061] Fig.11 yes Fig. 9 A right side view of the blank is provided;

[0062] Fig.12 It is a mold closing state diagram of the four-sequence positive mold and the four-sequence negative mold provided by the utility model;

[0063] Fig.13 yes Fig.12 The blank forming diagram provided;

[0064] Fig.14 yes Fig.13 A left side view of the blank is provided;

[0065] Fig.15 yes Fig.13 A right side view of the blank is provided;

[0066] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0067] 1A—first-order male mold, 1A.1—first-order male mold punch sleeve, 1A.2—first-order male mold ejector, 1A.3—first-order male mold cushion block, 1B—first-order female mold, 1B.1—first-order female mold sleeve, 1B.2—first-order expansion rod mold core, 1B.3—first-order female mold ejector, 2A—second-order male mold, 2A.1—second-order male mold punch sleeve, 2A.2—second-order male mold core, 2A.3—second-order male mold ejector, 2A.4—second-order male mold cushion block, 2B—second-order female mold, 2B.1—second-order female mold sleeve, 2B.2—second-order straight-through mold core, 2B.3—second-order female mold ejector, 3A—third-order male mold, 3A.1—third-order male mold punch sleeve, 3A.2—third-order Sequence positive mold core, 3A.3—three-sequence positive mold ejector pin, 3A.4—three-sequence positive mold cushion block, 3B—three-sequence negative mold, 3B.1—three-sequence negative mold sleeve, 3B.2—three-sequence straight-through mold core, 3B.3—three-sequence negative mold ejector pin, 4A—four-sequence positive mold, 4A.1—four-sequence positive mold punch sleeve, 4A.2—trimming mold, 4B—four-sequence negative mold, 4B.1—four-sequence negative mold sleeve, 4B.2—four-sequence straight-through mold core, 4B.3—four-sequence negative mold ejector pin, 10—first connector, a—plane, b—arc surface, c—first inclined surface, d—second inclined surface, 20—positioning shoulder, e—positioning surface, 30—second connector, aˊ—plane, bˊ—arc surface. DETAILED DESCRIPTION

[0068] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0069] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0070] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicating positions or positional relationships are based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific position, be constructed and operate in a specific position, and therefore should not be understood as limiting the present invention;

[0071] In addition, the descriptions involving the terms "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. The terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0072] In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0073] Embodiment 1

[0074] As attached Fig.13 To Attachment Fig.15 As shown, a special-shaped double-head connector is composed of a first connector 10, a second connector 30 and a positioning shoulder 20 located between the first connector and the second connector. The cross-section of the first connector 10 and the second connector 30 is a non-circular special-shaped surface.

[0075] Preferably, the first connector 10 is a columnar body composed of a plane a, a curved surface b, a first inclined surface c and a second inclined surface d, and the two connected surfaces are connected by a chamfered transition; the second connector 30 is a columnar body composed of a plane aˊ and a curved surface bˊ, wherein the arc forming the curved surface bˊ is the major arc, and the plane surface aˊ and the curved surface bˊ are connected by a chamfered transition.

[0076] Preferably, the plane a of the first connector 10 and the plane a' of the second connector 30 are misaligned or opposite in orientation. Specifically, in this embodiment, it is further preferred that the two planes are oppositely disposed.

[0077] Preferably, the connector is cold headed by a cold heading die on a multi-station forming machine, the heat treatment hardness reaches 420-490HV, and the surface is treated with Magnetics. Magnetics is a surface treatment technology mainly used to provide corrosion protection for substrates such as iron and aluminum.

[0078] Preferably, a positioning surface e is provided on the positioning shoulder 20 to facilitate positioning of the positioning clamping connector during installation.

[0079] The special-shaped double-headed connector designed in this embodiment has two connectors designed as special-shaped columns, so that after the two connectors are connected, they have good anti-torque effect and can effectively solve the problem of connection failure that may be caused by torque.

[0080] When processing the product, it is preferred to use a cold heading process, so this embodiment also provides a cold heading die for processing the special-shaped double-head connector.

[0081] The cold heading forming die includes four groups of male dies and four groups of female dies, wherein the four groups of male dies include a first-order male die 1A, a second-order male die 2A, a third-order male die 3A and a fourth-order male die 4A; the four groups of female dies include a first-order female die 1B, a second-order female die 2B, a third-order female die 3B and a fourth-order female die 4B corresponding to the first-order male die, the second-order male die, the third-order male die and the fourth-order male die respectively. The four groups of male dies and female dies are respectively installed in a multi-station forming machine, and the material blank is moved between the four groups of male dies and female dies through the clamping system of the forming machine, and the material blank is sequentially processed by head expansion and tail preforming, head preforming, head and tail forming, and trimming. Specifically, the head here corresponds to the first connector and positioning shoulder of the special-shaped double-head connector, and the tail corresponds to the second connector of the special-shaped double-head connector.

[0082] As attached Figure 1 As shown, the first-order male die 1A includes a first-order male die punch sleeve 1A.1, a first-order male die push rod 1A.2 and a first-order male die cushion block 1A.3; the first-order male die punch sleeve is fixedly installed on the forming machine; the first-order male die push rod movably penetrates and exposes the male die punch sleeve for punching the blank; the first-order male die cushion block is arranged in the male die punch sleeve for limiting the male die push rod.

[0083] As attached Figure 1 As shown, the first-order female mold 1B includes a first-order female mold sleeve 1B.1, a first-order expansion rod mold core 1B.2 and a first-order female mold push rod 1B.3; the first-order female mold sleeve is installed on the forming machine relative to the first-order male mold punch sleeve; the first-order expansion rod mold core is embedded in the end of the first-order female mold sleeve, and the first-order expansion rod mold core is provided with a cavity for expanding the head of the blank and pre-forming the tail; the first-order female mold push rod passes through the first-order female mold sleeve and extends into the cavity of the first-order expansion rod mold core, which is used to push out the blank and shape the tail of the blank.

[0084] When the first sequence is performing the head expansion and tail preforming, the clamping system of the forming machine sends the blank to the die mouth of the first sequence female mold. When the main slide of the forming machine moves toward the first sequence female mold, the blank is pushed into the first sequence expansion mold core under the action of the first sequence male mold. The main slide continues to move forward to the front point, and the material is compressed and deformed. The first sequence male mold ejector, the first sequence expansion mold core, and the first sequence female mold ejector jointly complete the head expansion and tail preforming of the blank. The formed part is as shown in the attached figure. Figure 2 and attached Figure 3 shown.

[0085] As attached Figure 4 As shown, the second-sequence male mold 2A includes a second-sequence male mold sleeve 2A.1, a second-sequence male mold core 2A.2, a second-sequence male mold push rod 2A.3 and a second-sequence male mold cushion block 2A.4; the second-sequence male mold sleeve is fixedly installed on the forming machine; the second-sequence male mold core is embedded in the end of the second-sequence male mold sleeve, and the second-sequence male mold core is provided with a cavity for the head of the preformed blank; the second-sequence male mold push rod is movably arranged in the second-sequence male mold sleeve, and one end extends into the cavity of the second-sequence male mold core for shaping the head of the blank; the second-sequence male mold cushion block is arranged in the second-sequence male mold sleeve for limiting the second-sequence male mold push rod.

[0086] As attached Figure 4 As shown, the second-order female mold 2B includes a second-order female mold sleeve 2B.1, a second-order straight-through mold core 2B.2 and a second-order female mold push rod 2B.3; the second-order female mold sleeve is installed on the forming machine relative to the second-order male mold punch sleeve; the second-order straight-through mold core is embedded in the end of the second-order female mold sleeve relative to the second-order male mold core, and the second-order straight-through mold core is provided with a cavity for constraining the tail of the blank; the second-order female mold push rod passes through the second-order female mold sleeve and extends into the cavity of the second-order straight-through mold core, which is used to push out the blank and shape the tail of the blank.

[0087] When the second sequence is performing head preforming, the clamping system of the forming machine sends the blank to the die mouth of the second sequence female die. When the main slide of the forming machine moves toward the second sequence female die, the blank is pushed into the second sequence straight-through die core by the second sequence male die. The main slide continues to move forward to the front point, and the material is compressed and deformed. The second sequence male die core, the second sequence male die ejector rod, the second sequence straight-through die core, and the second sequence female die ejector rod jointly complete the head preforming of the blank and the shape of the constrained rod. The formed part is as shown in the attached figure. Figure 5 To Attachment Figure 7 shown.

[0088] As attached Figure 8 As shown, the three-sequence positive mold 3A includes a three-sequence positive mold sleeve 3A.1, a three-sequence positive mold core 3A.2, a three-sequence positive mold push rod 3A.3 and a three-sequence positive mold cushion block 3A.4; the three-sequence positive mold sleeve is fixedly installed on the forming machine; the three-sequence positive mold core is embedded in the end of the three-sequence positive mold sleeve, and the three-sequence positive mold core is provided with a cavity for forming the head of the blank; the three-sequence positive mold push rod is movably arranged in the three-sequence positive mold sleeve, and one end extends into the cavity of the three-sequence positive mold core for shaping the head of the blank; the three-sequence positive mold cushion block is arranged in the three-sequence positive mold sleeve for limiting the three-sequence positive mold push rod.

[0089] As attached Figure 8 As shown, the three-sequence female mold 3B includes a three-sequence female mold sleeve 3B.1, a three-sequence straight-through mold core 3B.2 and a three-sequence female mold push rod 3B.3; the three-sequence female mold sleeve is installed on the forming machine relative to the three-sequence male mold punch sleeve; the three-sequence straight-through mold core is embedded in the end of the three-sequence female mold sleeve relative to the three-sequence male mold core, and the three-sequence straight-through mold core is provided with a cavity for constraining the tail of the blank; the three-sequence female mold push rod passes through the three-sequence female mold sleeve and extends into the cavity of the three-sequence straight-through mold core, which is used to push out the blank and shape the tail of the blank.

[0090] When the three-sequence forming is performed for the head and tail, the clamping system of the forming machine sends the blank to the die mouth of the three-sequence female die. When the main slide of the forming machine moves toward the three-sequence female die, the blank is pushed into the three-sequence straight-through die core by the three-sequence male die. The main slide continues to move forward to the front point, and the material is compressed and deformed. The three-sequence male die core, the three-sequence male die ejector rod, the three-sequence straight-through die core, and the three-sequence female die ejector rod jointly complete the preforming of the blank's head and the shape of the constrained rod. The formed part is as shown in the attached figure. Fig. 9 To Attachment Fig.11 shown.

[0091] As attached Fig.12 As shown, the four-sequence positive die 4A includes a four-sequence positive die punch sleeve 4A.1 and a trimming die 4A.2; the four-sequence positive die punch sleeve is fixedly installed on the forming machine; the trimming die is annular, and its inner cavity can accommodate the head of the blank, and the trimming die is embedded in the four-sequence positive die punch sleeve to cut out the positioning shoulder of the head of the blank.

[0092] As attached Fig.12As shown, the four-sequence female mold 4B includes a four-sequence female mold sleeve 4B.1, a four-sequence straight-through mold core 4B.2 and a four-sequence female mold push rod 4B.3; the four-sequence female mold sleeve is installed on the forming machine relative to the four-sequence male mold punch sleeve; the four-sequence straight-through mold core is embedded in the end of the four-sequence female mold sleeve relative to the trimming mold, and the four-sequence straight-through mold core is provided with a cavity for constraining the tail of the blank; the four-sequence female mold push rod passes through the four-sequence female mold sleeve and extends into the cavity of the four-sequence straight-through mold core, which is used to push out the blank and shape the tail of the blank.

[0093] When the four-sequence is trimming, the clamping system of the forming machine sends the blank to the die mouth of the four-sequence female die. When the main slide of the forming machine moves toward the four-sequence female die, the blank is pushed into the four-sequence straight-through die core by the four-sequence male die. The main slide continues to move forward to the front point. The four-sequence straight-through die core and the four-sequence female die ejector rod are used to fix and constrain the blank. The trimming die completes the trimming of the positioning shoulder. The molded part is as shown in the attached figure. Fig.13 To Attachment Fig.15 shown.

[0094] The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A special-shaped double-head connector, comprising a first connector, a second connector and a positioning shoulder between the first connector and the second connector; characterized in that: The cross-sections of the first connector and the second connector are non-circular shaped surfaces; The connecting piece is formed by cold heading on a multi-station forming machine using a cold heading forming die.

2. The special-shaped double-ended connector according to claim 1, characterized in that: The first connector is a columnar body consisting of a plane, a curved surface, a first inclined surface and a second inclined surface, and the two connected surfaces are connected by a rounded transition; The second connector is a columnar body consisting of a plane and an arc surface, wherein the arc forming the arc surface is a major arc, and the plane and the arc surface are connected by a chamfered transition.

3. The special-shaped double-ended connector according to claim 2, characterized in that: The plane of the first connector and the plane of the second connector are misaligned or opposite in orientation.

4. The special-shaped double-ended connector according to claim 1, characterized in that: The heat treatment hardness of the connecting piece reaches 420-490 HV, and the surface is Magnetic treated.

5. The special-shaped double-ended connector according to claim 1, characterized in that: The positioning shoulder is provided with a positioning surface for positioning during installation.

6. A cold heading die, characterized in that: Used for processing the special-shaped double-end connector as claimed in any one of claims 1 to 5, comprising: Four groups of positive molds, including a one-sequence positive mold, a two-sequence positive mold, a three-sequence positive mold and a four-sequence positive mold; Four groups of negative molds, including a first-order negative mold, a second-order negative mold, a third-order negative mold, and a fourth-order negative mold corresponding to the first-order positive mold, the second-order positive mold, the third-order positive mold, and the fourth-order positive mold respectively; The four groups of male and female molds are respectively installed on the multi-station forming machine. The blank is moved between the four groups of male and female molds through the clamping system of the forming machine, and the blank is sequentially processed by head expansion and tail preforming, head preforming, head and tail forming, and trimming.

7. The cold heading forming die according to claim 6, characterized in that: The first-order positive mold comprises: A first-order male die punch sleeve, fixedly installed on the molding machine; A first-order male die ejector pin, which moves through and exposes the male die punch sleeve, is used for punching the blank; A first-order male mold pad is arranged in the male mold punch sleeve and is used to limit the male mold ejector rod; The first-order negative mold comprises: A first-order female die sleeve is installed on the molding machine opposite to a first-order male die sleeve; A first-order expansion rod mold core is embedded in the end of a first-order female mold sleeve, and a cavity for expanding the head of the blank and preforming the tail is provided in the first-order expansion rod mold core; The first-order female mold ejector rod penetrates the first-order female mold sleeve and extends into the cavity of the first-order expansion rod mold core, and is used for pushing out the blank and shaping the tail of the blank.

8. The cold heading forming die according to claim 6, characterized in that: The two-order positive mold comprises: A second-order male die punch sleeve is fixedly installed on the molding machine; A second-order male mold core is embedded in the end of the second-order male mold punch sleeve, and a cavity for the head of the preform blank is provided in the second-order male mold core; The second-order male mold ejector rod is movably arranged in the second-order male mold punch sleeve, and one end of the ejector rod extends into the cavity of the second-order male mold core, and is used for shaping the head of the blank; The second-order male mold cushion block is arranged in the second-order male mold punch sleeve and is used to limit the second-order male mold ejector rod; The two-order negative mold comprises: A second-order female die sleeve is installed on the molding machine relative to the second-order male die sleeve; A second-order straight-through mold core is embedded in the end of the second-order female mold sleeve relative to the second-order male mold core, and a cavity for constraining the tail of the blank is provided in the second-order straight-through mold core; The second-order female mold ejector rod passes through the second-order female mold sleeve and extends into the cavity of the second-order straight-through mold core, and is used to push out the blank and shape the tail of the blank.

9. The cold heading forming die according to claim 6, characterized in that: The three-sequence positive mold comprises: A three-stage male die punch sleeve, fixedly mounted on the molding machine; A three-sequence male die core is embedded in the end of the three-sequence male die punch sleeve, and a cavity for molding the head of the blank is provided in the three-sequence male die core; The three-sequence male die ejector rod is movably arranged in the three-sequence male die punch sleeve, and one end of the ejector rod extends into the cavity of the three-sequence male die core, and is used for shaping the head of the blank; The three-sequence male mold pad is arranged in the three-sequence male mold punch sleeve and is used to limit the three-sequence male mold ejector rod; The three-order negative mold comprises: A three-sequence female die sleeve is installed on the molding machine relative to the three-sequence male die sleeve; A three-sequence straight-through mold core is embedded in the end of the three-sequence female mold sleeve relative to the three-sequence male mold core, and a cavity for constraining the tail of the blank is provided in the three-sequence straight-through mold core; The three-stage female mold ejector rod passes through the three-stage female mold sleeve and extends into the cavity of the three-stage straight-through mold core, and is used for pushing out the blank and shaping the tail of the blank.

10. The cold heading forming die according to claim 6, characterized in that: The four-sequence positive mold comprises: Four-sequence male die punch sleeve, fixedly installed on the molding machine; The trimming die is annular, and its inner cavity can accommodate the head of the blank. The trimming die is embedded in the four-sequence male die punch sleeve and is used to cut out the positioning shoulder of the blank head; The four-order negative mold includes: A four-sequence female die sleeve is installed on the molding machine relative to the four-sequence male die punch sleeve; A four-sequence straight-through mold core is embedded in the end of the four-sequence female mold sleeve relative to the trimming mold, and a cavity for constraining the tail of the blank is provided in the four-sequence straight-through mold core; The ejector rod of the four-sequence female mold passes through the four-sequence female mold sleeve and extends into the cavity of the four-sequence straight-through mold core, and is used to push out the blank and shape the tail of the blank.

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