A punch mechanism of a cold header

Abstract

The utility model belongs to cold upsetting equipment technical field especially relates to a punch mechanism of cold header, include: frame, be provided with driving motor on the frame, still include: camshaft, camshaft rotation setting in the frame and through the coupling with driving motor's output end connection, drive cam, drive cam has two cam parts, two cam parts are 180 degrees angle staggered and about camshaft axis center symmetry around camshaft axis, punch head part, punch head part passes through lower support seat and drive cam's cam part abuts to accept drive cam rotation when providing the punch pressure of the punch head part, punch head part has detachable embedded mould, wherein, drive cam drives rotation through camshaft, punch head part reciprocating motion up and down along the stroke axis. Relative to the prior art, the utility model improves the work stability of the punch mechanism, effectively reduces the production cost.

Description

Technical Field

[0001] This utility model belongs to the technical field of cold heading equipment, and in particular relates to a stamping mechanism of a cold heading machine. Background Technology

[0002] A cold heading machine is a type of metal stamping production equipment. Most cold heading machines utilize a cam mechanism to drive the stamping head in a reciprocating motion. One revolution of the cam completes one stroke of the stamping head. For example, patent application CN201720754727.8 discloses a cam device for a cold heading machine. This device includes a cam and a camshaft, with a damping mechanism between the cam and the camshaft. This damping mechanism includes a fixed ring sleeved on the camshaft and a damping ring disposed between the fixed ring and the cam. The existing cold heading machine stamping mechanism has added a shock-absorbing structure to reduce the vibration of the cam during operation. However, the cam still needs an additional mass balancing mechanism to balance it in order to reduce the centrifugal force vibration generated when the cam rotates and ensure the working stability of the stamping mechanism. At the same time, the stamping head of the existing cold heading machine stamping mechanism is usually an integral structure. After damage, it usually needs to be disassembled as a whole. The replacement of inserts is cumbersome and time-consuming. In addition, the whole is made of precious metals. After local wear, the whole is scrapped, which increases the production cost. Therefore, it is necessary to make improvements. Utility Model Content

[0003] The purpose of this invention is to address the aforementioned technical problems by providing a stamping mechanism for a cold heading machine, thereby improving the working stability of the stamping mechanism and reducing production costs.

[0004] In view of this, the present invention provides a stamping mechanism for a cold heading machine, comprising: A frame, on which a drive motor is mounted; Also includes: A camshaft, which is rotatably mounted in the frame and connected to the output end of a drive motor via a coupling; A drive cam having two cam portions that are offset at a 180° angle around the camshaft axis and are symmetrical about the center of the camshaft axis. A punch head, which abuts against the cam portion of a drive cam via a lower support to receive punching force provided when the drive cam rotates, the punch head having a removable embedded die; The driving cam is driven to rotate by a camshaft, and the punch head moves up and down along the stroke axis.

[0005] In this technical solution, the drive motor drives the camshaft to rotate, and the camshaft drives the drive cam to rotate synchronously. When the cam portion (long shaft side) of the drive cam rotates to contact the lower support, the cam portion pushes the lower support to move downward. The lower support drives the punch to move downward along the stroke axis. The die of the punch extends from the bottom opening of the frame to extrude and form the metal billet, completing the cold heading stamping action. When the cam portion (short shaft side) of the drive cam rotates to contact the lower support, the punch begins its return stroke, returning to its initial position. Simultaneously, another cam portion begins to rotate to contact the lower support, preparing for the next stamping action. The drive motor continues to run, and the camshaft rotates... In one revolution, the two cams of the drive cam push the punch head to complete two stamping-return cycles. When the wear of the embedded die exceeds the tolerance, the embedded die is disassembled after the machine is stopped, replaced with a new embedded die, and reassembled to resume production. Compared with the existing technology, the drive cam of this utility model adopts a design of two 180° symmetrical cam parts, forming a complete mass balance with the cam shaft axis as the center. There is no need to configure additional counterweights, balance shafts, or other mass balancing mechanisms, which simplifies the equipment structure, reduces manufacturing costs, and improves the working stability of the stamping mechanism. At the same time, the punch head adopts a detachable embedded die, and only the corresponding embedded die needs to be replaced after local wear, which effectively reduces production costs.

[0006] Furthermore, the above technical solution also includes: An upper support seat is provided above the drive cam to transmit the stamping reaction force to the frame.

[0007] In the above technical solution, furthermore, the surfaces of the lower support and the upper support facing the drive cam both have elliptical cross sections to cooperate with the rotational movement of the drive cam.

[0008] In the above technical solution, the surfaces of the lower support and the upper support facing the drive cam are further provided with a smooth layer to reduce friction between the lower support, the upper support and the drive cam.

[0009] In the above technical solution, the punch head further includes: The punch housing has a tapered through hole at the bottom and an insertion hole at the top; A sleeve, wherein the sleeve has a tapered cylindrical structure adapted to fit a tapered through hole, and the side of the sleeve has a slit along the length direction; A pressure block, wherein the pressure block is embedded in an embedding hole and the bottom diameter of the pressure block is adapted to the inner diameter of the embedding hole, and the top diameter is smaller than the inner diameter of the embedding hole; A clamping bolt, which is fastened to the top of the embedded hole by a threaded connection, is used to fix the axial position of the pressure block and the sleeve; Wherein, the lower port diameter of the tapered through hole is smaller than the upper port diameter, the tapered through hole is connected to the embedding hole and the diameter of the embedding hole is larger than the upper port diameter of the tapered through hole, the outer surface of the embedding mold is a tapered surface that fits the sleeve and the embedding mold is embedded and accommodated in the sleeve by pressing.

[0010] The beneficial effects of this utility model are: 1. The drive cam employs a design with two 180° symmetrical cam sections, forming a complete mass balance centered on the camshaft axis. This eliminates the need for additional counterweights, balance shafts, or other mass balancing mechanisms, simplifying the equipment structure and reducing manufacturing costs. Simultaneously, the symmetrical structure counteracts the centrifugal force generated during cam rotation, reducing radial vibration of the camshaft and improving the overall operational stability of the stamping mechanism. Furthermore, while traditional single-cam drives require one rotation to complete one stroke, the dual-symmetrical cam section of this invention allows each cam section to push the lower support seat once per camshaft rotation, achieving two strokes. This significantly increases the stroke frequency compared to traditional structures, greatly improving cold heading production efficiency and meeting the demands of high-cycle production.

[0011] 2. The punch head adopts a detachable structure of "punch head shell + sleeve + embedded mold". The embedded mold is a vulnerable part that directly contacts the metal blank. Its replacement does not require disassembling the entire punch head: simply loosen the clamping bolt and remove the pressure block, and the embedded mold can be removed through the cut deformation of the sleeve. This improves replacement efficiency and reduces production costs.

[0012] 3. A smooth layer is provided on the arc-shaped contact surface of the lower and upper support seats, which reduces the coefficient of friction between the drive cam and the support seats, thus reducing friction loss compared to traditional structures without a smooth layer. The upper support seat directly transmits the stamping reaction force to the frame, avoiding bending stress on the cam bearing and resulting in a better stress state for the camshaft. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the structure of a specific embodiment of the present utility model.

[0015] Figure 2 This is a side view structural diagram of the present invention.

[0016] Figure 3 This is a schematic diagram of the punch head structure of this utility model.

[0017] Figure 4 This is an exploded view of the punch head structure of this utility model.

[0018] Figure 5 This is a schematic cross-sectional view of the punch head of this utility model.

[0019] The markings in the diagram are as follows: 1. Camshaft; 2. Drive cam; 3. Cam section; 4. Punch head; 40. Embedded mold; 41. Punch housing; 42. Tapered through hole; 43. Embedded hole; 44. Sleeve; 45. Cutout; 46. Pressure block; 47. Clamping bolt; 5. Lower support seat; 6. Upper support seat; 7. Smooth layer. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] In the description of this application, it should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. For ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0022] Overall composition The stamping mechanism of a cold heading machine includes a frame, a drive motor, a camshaft 1, a drive cam 2, a punch head 4, an upper support seat 6, a lower support seat 5, and also includes conventional guide bearings, preload springs, and bolt connection mechanisms.

[0023] frame The frame, serving as the mounting base for the entire stamping mechanism, is welded from Q345B low-alloy high-strength structural steel. It has an internal mounting cavity machined along the vertical direction (i.e., the stroke axis direction). The bottom of the mounting cavity has a circular opening (for the punch head 4 to extend), and a mounting groove for the guide bearing is reserved at the opening. The side wall of the frame is also machined with support holes for the camshaft 1, fixing holes for the upper support seat 6, and positioning grooves for the preload spring, ensuring the assembly accuracy of each component.

[0024] drive motor The drive motor is a servo motor (such as a Siemens servo motor with model number 1FL6064-1AC61-0AB1), and its output end is connected to the camshaft 1 through a coupling; the servo motor can be speed regulated by a conventional PLC control system, thereby controlling the stroke frequency of the punch head 4.

[0025] Camshaft 1 Camshaft 1 is made of 40CrNiMoA alloy structural steel through integral forging, quenching and tempering and precision grinding. Its two ends are rotatably supported in the support holes of the frame by deep groove ball bearings. The middle part of camshaft 1 and drive cam 2 are integrally machined (or fixed by key connection to ensure no relative rotation), and the axis of camshaft 1 is perpendicular to the stroke axis of punch head 4 to ensure accurate conversion of transmission direction.

[0026] Drive cam 2 and support base The drive cam 2 integrates two cam sections 3 that are circumferentially offset at a 180° angle along the axis of the camshaft 1, and the two cam sections 3 form a centrally symmetrical structure with the axis of the camshaft 1 as the center; the outer periphery of each cam section 3 is an "eccentric arc with an elliptical cross section" - the length of its major axis can be 50-80mm, and the length of its minor axis can be 30-50mm (the specific dimensions are adjusted according to the required stroke of the cold heading product, and the stroke amount is 1 / 2 of the difference between the major axis and the minor axis); the surface of the cam section 3 is nitrided (nitriding layer depth 0.3-0.5mm, surface hardness reaches HV800-1000) to improve wear resistance.

[0027] The lower support seat 5 is made of 45 steel with heat treatment (HRC22-25). Its top is machined with an arc-shaped contact surface that matches the outer contour of the drive cam 2. The cross-section of the contact surface is elliptical (with the same radius of curvature as the cross-section of the cam part 3), ensuring that the drive cam 2 forms a surface contact transmission with the lower support seat 5 when it rotates. The bottom of the lower support seat 5 is fixedly connected to the top of the punch head 4 through a bolt connection mechanism (such as an M12 hexagon socket head cap bolt, with a spring washer to prevent loosening), so as to realize the transmission of punching force.

[0028] Upper support 6: The structure is symmetrical to the lower support 5. It is also made of 45 steel with heat treatment. Its bottom is machined with an elliptical cross-section arc contact surface that matches the outer contour of the drive cam 2. The top is fixedly connected to the top of the mounting cavity of the frame through a bolt connection mechanism. The function of the upper support 6 is to bear the impact reaction force generated when the drive cam 2 rotates and to directly transmit the reaction force to the frame, so as to avoid the camshaft 1 bearing additional bending stress.

[0029] A smooth layer 7 is provided on the arc-shaped contact surfaces of both the lower support 5 and the upper support 6. The smooth layer 7 can be implemented in two ways: Option 1 is a polytetrafluoroethylene (PTFE) coating with a thickness of 0.05-0.1 mm. The low coefficient of friction of PTFE (0.04-0.08) reduces the sliding friction between the cam part 3 and the support. Option 2 is a copper-based alloy (such as CuSn10P) plating with a thickness of 0.1-0.2 mm. The self-lubricating properties of the metal alloy improve wear resistance, while also having good thermal conductivity to dissipate frictional heat in a timely manner.

[0030] Preferably, a radial lubrication channel can be machined at the mounting hole of the upper support seat 6 of the frame. One end of the lubrication channel is connected to the arc-shaped contact surface of the upper support seat 6, and the other end is connected to the centralized lubrication system of the equipment through an oil pipe. The centralized lubrication system can inject lithium-based grease (model GB / T7324-2010) into the contact surface at regular intervals (such as once every 30 minutes) to ensure sufficient lubrication between the drive cam 2 and the support seat, and further reduce friction loss.

[0031] Strike the head 4 The punch housing 41 is made of 5CrNiMo hot work die steel through forging, quenching and tempering (HRC40-45). It has a through stepped hole machined along the axial direction inside – a tapered through hole 42 at the bottom and an embedded hole 43 at the top. The lower port diameter (20-40mm) of the tapered through hole 42 is smaller than the upper port diameter (30-50mm), and the taper is 1:5 (i.e., the diameter increases by 1mm for every 5mm increase in axial direction), ensuring a tight tapered fit of the sleeve 44. The diameter (40-60mm) of the embedded hole 43 is larger than the upper port diameter of the tapered through hole 42, forming a stepped surface to bear the axial pressure of the pressure block 46.

[0032] The sleeve 44 is made of WC-Co cemented carbide (containing 8%-12% cobalt, with a hardness of HRA88-90). Its shape is a tapered cylinder structure adapted to the tapered through hole 42. The inner diameter of the sleeve 44 (15-35mm) is consistent with the outer diameter of the embedded mold 40, and it is used to accommodate the embedded mold 40. A through cut 45 is opened on the side of the sleeve 44 along its axial length direction. The width of the cut 45 is 2-3mm, and the depth is 1 / 3-1 / 2 of the wall thickness of the sleeve 44 (e.g., when the wall thickness of the sleeve 44 is 5mm, the depth of the cut 45 is 1.5-2.5mm). The function of the cut 45 is: when the embedded mold 40 is pressed in, the sleeve 44 can adapt to the dimensional deviation of the mold through slight deformation to ensure a tight fit. At the same time, when disassembling the mold, the cut 45 provides deformation space to facilitate the removal of the mold.

[0033] The embedded mold 40 is made of ultra-fine grain WC-Co cemented carbide (containing 6%-8% cobalt, with a hardness of HRA90-92). Its outer surface is a conical shape that matches the inner hole of the sleeve 44 (the taper is consistent with the sleeve 44, which is 1:5). The inner hole is machined into the forming cavity of cold-forged products (such as the hexagonal or circular contour of the bolt head). The embedded mold 40 is embedded in the sleeve 44 by "press-fit", without the need for additional fasteners, and is fixed by the interference fit of the conical surface.

[0034] The pressure block 46 is made of No. 45 steel and has a stepped cylindrical shape. The bottom diameter (38-58mm) is matched with the inner diameter of the insertion hole 43 (clearance fit, fit clearance 0.02-0.05mm), and the top diameter (30-48mm) is smaller than the inner diameter of the insertion hole 43, forming an annular stepped surface.

[0035] The clamping bolt 47 is an 8.8 grade high-strength bolt (model M16-M24), which is fastened to the internal thread at the top of the insertion hole 43 by threaded connection (the top of the insertion hole 43 is machined with an internal thread that matches the clamping bolt 47). The clamping bolt 47 also has an axial through hole at the center for the top of the pressure block 46 to be inserted. When the clamping bolt 47 is tightened, its bottom end can abut against the bottom annular step surface of the pressure block 46, and the pressure block 46 axially presses the sleeve 44 into the tapered through hole 42 of the punch housing 41 to prevent the sleeve 44 from moving axially during the stamping process. After loosening the clamping bolt 47, the pressure block 46 can be removed first, and then an external force can be applied from the cut 45 of the sleeve 44 by a special tool (such as a push rod with a tapered head) to make the sleeve 44 slightly deformed, and the insertion mold 40 can be easily removed.

[0036] Preferably, a limiting groove is provided on the bottom surface of the pressure block 46, and the top of the embedded mold 40 has a limiting protrusion that cooperates with the limiting groove. The radial displacement of the embedded mold 40 is further restricted by the cooperation between the limiting groove and the limiting protrusion.

[0037] The embedded mold 40 is made of high-hardness ultra-fine grain WC-Co cemented carbide, while the punch housing 41 and sleeve 44 are made of relatively low-cost materials (5CrNiMo, conventional WC-Co). After local wear, only the embedded mold 40 needs to be replaced, without the need for complete scrapping, which effectively reduces material costs. At the same time, the cut 45 of the sleeve 44 is designed to accommodate embedded molds 40 with slight dimensional deviations, which improves the versatility of the mold, reduces the number of spare molds in stock, and lowers inventory management costs.

[0038] Guiding and return structure The guide bearing adopts a linear ball bearing (model LM30UU). Its outer ring is fixed in the open mounting groove at the bottom of the frame by interference fit, and the inner ring forms a clearance fit with the outer circumferential surface of the punch housing 41 (fit clearance 0.01-0.03mm). There are two guide bearings, which are arranged at intervals along the stroke axis (spacing 50-80mm) to ensure that the radial runout of the punch head 4 along the stroke axis during reciprocating movement is less than 0.02mm, thereby improving the dimensional accuracy of cold heading products.

[0039] Preload spring: A cylindrical helical compression spring (material: 60Si2MnA spring steel, diameter: φ8-φ12mm, free length: 100-150mm, stiffness coefficient: 50-80N / mm) is adopted. One end of the preload spring is connected to the bottom of the lower support seat 5 through the spring seat (the spring seat is fixed to the lower support seat 5 by bolts), and the other end is connected to the bottom of the frame mounting cavity through the spring seat. The preload spring is in a pre-compressed state during assembly (pre-compression amount: 10-20mm). Its elasticity can ensure that when the drive cam 2 rotates to the non-push stroke section, the lower support seat 5 is always in contact with the outer circumference of the drive cam 2, thereby driving the punch head 4 to complete the return stroke and avoiding return stroke jamming. At the same time, the elasticity of the preload spring can be finely adjusted by adjusting the position of the spring seat (the spring seat is machined with an elongated hole) to adapt to the return speed requirements of different cold heading processes.

[0040] Working principle Start-up phase: The drive motor is started through the PLC control system. The drive motor drives the camshaft 1 to rotate, and the camshaft 1 drives the drive cam 2 to rotate synchronously. At this time, the pre-tension spring is in a pre-compressed state, and its elasticity keeps the lower support seat 5 in contact with the outer periphery of the drive cam 2.

[0041] Stamping stage: When the cam part 3 (long shaft side) of the drive cam 2 rotates to contact the lower support seat 5, the cam part 3 pushes the lower support seat 5 to move downward, and the lower support seat 5 drives the punch head 4 to move downward along the stroke axis (the guide bearing ensures that the punch head 4 has no radial offset); the embedded die 40 of the punch head 4 extends out from the bottom opening of the frame to extrude and form the metal billet, completing the cold heading stamping action; during this process, the preload spring is further compressed to store elastic potential energy; the upper support seat 6 bears the stamping reaction force transmitted by the cam and transmits the reaction force to the frame to avoid the camshaft 1 being stressed.

[0042] Return stroke phase: When the cam part 3 (short shaft side) of the drive cam 2 rotates to contact the lower support seat 5, the preload spring releases its elastic potential energy, pushing the lower support seat 5 to move upward. The lower support seat 5 drives the punch head 4 to move upward along the stroke axis and return to the initial position. At the same time, another cam part 3 begins to rotate to contact the lower support seat 5, preparing for the next stamping action.

[0043] Continuous production: The drive motor runs continuously. For each rotation of the camshaft 1, the two cam sections 3 of the drive cam 2 push the punch head 4 to complete two stamping-return cycles, realizing continuous cold heading production. When the wear of the embedded mold 40 exceeds the tolerance (such as the cavity size deviation exceeding 0.05mm), after stopping the machine, loosen the clamping bolt 47, remove the pressure block 46, and use the ejector rod to push out the embedded mold 40 from the cut 45 of the sleeve 44. After replacing the new embedded mold 40 and reassembling, production can be resumed.

[0044] Beneficial effects The drive stability is improved and the stroke frequency is doubled. The drive cam 2 adopts a design of two 180° symmetrical cam sections 3, which form a complete mass balance with the axis of camshaft 1 as the center. There is no need to configure additional counterweights, balance shafts and other mass balancing mechanisms, which simplifies the equipment structure and reduces manufacturing costs. At the same time, the symmetrical structure can counteract the centrifugal force generated when the cam rotates, which reduces the radial vibration of camshaft 1 and improves the operating stability of the entire stamping mechanism.

[0045] Traditional single-cam drive requires one rotation to complete one stroke, while the double-symmetrical cam section 3 of the present invention can push the lower support seat 5 once when the camshaft 1 rotates once, realizing two strokes. The stroke frequency is improved compared with the traditional structure, which significantly improves the cold heading production efficiency and meets the needs of high-cycle production.

[0046] The mold is easy to replace and the operation and maintenance costs are reduced. The punch head 4 adopts a split structure of "punch head shell 41 + sleeve 44 + embedded mold 40". The embedded mold 40 is a vulnerable part that directly contacts the metal blank. Its replacement does not require disassembling the entire punch head 4: just loosen the clamping bolt 47 and take out the pressure block 46, and the embedded mold 40 can be taken out through the cut 45 of the sleeve 44. The replacement efficiency is improved and the downtime of the equipment is greatly reduced.

[0047] The embedded mold 40 is made of high-hardness ultra-fine grain WC-Co cemented carbide, while the punch housing 41 and sleeve 44 are made of relatively low-cost materials (5CrNiMo, conventional WC-Co). After local wear, only the embedded mold 40 needs to be replaced, without the need for complete scrapping, thus reducing material costs. At the same time, the cut 45 of the sleeve 44 is designed to accommodate embedded molds 40 with slight dimensional deviations, improving the versatility of the mold, reducing the number of spare molds in stock, and lowering inventory management costs.

[0048] Reduced transmission friction and extended service life: The arc-shaped contact surfaces of the lower support 5 and the upper support 6 are provided with a smooth layer 7 (PTFE coating or copper-based alloy plating), which, together with the timed lubrication of the centralized lubrication system, reduces the coefficient of friction between the drive cam 2 and the support. Compared with the traditional structure without the smooth layer 7, friction loss is reduced.

[0049] The upper support 6 directly transmits the stamping reaction force to the frame, avoiding bending stress on the camshaft 1, resulting in a better stress state for the camshaft 1. At the same time, the camshaft 1 is made of 40CrNiMoA alloy structural steel, which has high strength and high toughness and can withstand long-term high-frequency impact loads, reducing failures such as breakage and bending of the camshaft 1.

[0050] With strong structural compatibility and easy promotion, the technical solution of this invention retains the core functions of the stamping mechanism of conventional cold heading machines, and only improves the drive cam 2, punch head 4 and guide return structure. The remaining components (such as drive motor, frame, centralized lubrication system) can all adopt the standardized components of existing equipment, without the need to make overall modifications to the cold heading machine. The modification cost is low and it is easy to promote and apply on existing cold heading equipment.

[0051] The elliptical cross-sectional profile of the drive cam can be adjusted according to the stroke requirements of different cold heading products (such as the difference between the major and minor axes). The inner cavity of the embedded mold can also be customized according to the product profile, which has good process compatibility and can be applied to the cold heading production of various standardized fasteners such as bolts, screws, and rivets.

[0052] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A stamping mechanism for a cold heading machine, comprising: A frame, on which a drive motor is mounted; Its characteristic is that it further includes: Camshaft (1), which is rotatably mounted in the frame and connected to the output end of the drive motor via a coupling; The driving cam (2) has two cam portions (3), which are offset at an angle of 180° around the axis of the camshaft (1) and are symmetrical about the center of the axis of the camshaft (1); Punch head (4), which abuts against the cam portion (3) of the drive cam (2) via a lower support (5) to receive the punching force provided when the drive cam (2) rotates, and the punch head (4) has a removable insert mold (40); The driving cam (2) is driven to rotate by the camshaft (1), and the punch head (4) moves up and down along the stroke axis.

2. The stamping mechanism of a cold heading machine according to claim 1, characterized in that, Also includes: The upper support (6) is positioned above the drive cam (2) to transmit the stamping reaction force to the frame.

3. The stamping mechanism of a cold heading machine according to claim 2, characterized in that: The surfaces of the lower support (5) and the upper support (6) facing the drive cam (2) both have elliptical cross sections to accommodate the rotational movement of the drive cam (2).

4. The stamping mechanism of a cold heading machine according to claim 3, characterized in that: The surfaces of the lower support (5) and the upper support (6) facing the drive cam (2) are provided with a smooth layer (7) to reduce friction between the lower support (5), the upper support (6) and the drive cam (2).

5. The stamping mechanism of a cold heading machine according to claim 4, characterized in that, The punch head (4) also includes: The punch housing (41) has a tapered through hole (42) at the bottom and an embedding hole (43) at the top. Sleeve (44), the sleeve (44) is a tapered cylinder structure adapted to the tapered through hole (42), and the side of the sleeve (44) is provided with a cut (45) along the length direction; A pressure block (46) is embedded in an embedding hole (43) and the bottom diameter of the pressure block (46) is adapted to the inner diameter of the embedding hole (43), and the top diameter is smaller than the inner diameter of the embedding hole (43); A clamping bolt (47) is fastened to the top of the embedded hole (43) by a threaded connection to fix the axial position of the pressure block (46) and the sleeve (44); Wherein, the lower port diameter of the tapered through hole (42) is smaller than the upper port diameter, the tapered through hole (42) is connected to the embedding hole (43) and the diameter of the embedding hole (43) is larger than the upper port diameter of the tapered through hole (42), the outer surface of the embedding mold (40) is a tapered surface that is adapted to the sleeve (44) and the embedding mold (40) is embedded and accommodated in the sleeve (44) by pressing.

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