Chassis mounting welding sleeve and manufacturing method thereof

Abstract

The invention relates to the technical field of cold heading forming, and discloses a chassis mounting welding sleeve and a manufacturing method thereof.The method comprises the steps that after spheroidizing annealing is conducted on a wire rod, primary drawing, secondary spheroidizing annealing and secondary drawing are conducted, and a workpiece to be subjected to cold heading is obtained; straightening the wire rod through a primary die, and pressing the blank into a die forming hole by using a punching rod to punch a shaping pit; drawing an inner hole by using a secondary die, adjusting the diameter and the length, and adding a head type chamfering die core; stretching the rear hole by using a three-sequence die to form a flange pre-contour; extending the existing inner hole by using a four-sequence die to reach a target depth; forming a straight cylinder, a welding groove and an exhaust groove by using a five-sequence mold; a center hole of the sleeve is punched through through a six-sequence die to form a through hole, and a workpiece to be subjected to finish machining is formed; and carrying out inner hole turning and barrel plating to obtain the chassis mounting welding sleeve. According to the method, the problems of size error superposition and process discontinuity in the traditional machining process are solved, and the consistency of the product structure is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of cold heading forming, and in particular, to a chassis-mounted welding sleeve and a manufacturing method thereof. Background Art

[0002] With the rapid development of the new energy vehicle industry, the chassis of the vehicle has put forward higher requirements for the strength, precision and assembly efficiency of the battery pack mounting structure. In the design of the electric vehicle chassis, the mounting welding sleeve, as an important component connecting the bearing member and the chassis, its structural stability and processing technology are directly related to the safety performance and manufacturing cost of the whole vehicle.

[0003] In the prior art, the welding sleeve is generally made by traditional bar turning or single-step stamping. Such methods generally have problems such as low material utilization rate, poor forming efficiency, and insufficient product consistency. Especially when facing complex geometries (such as welding grooves, exhaust grooves) and precision inner hole structures, dimensional deviation accumulation often occurs due to multi-step processing, increasing subsequent correction processes. In addition, the traditional process does not systematically temper the raw materials for high-strength cold heading requirements, resulting in quality problems such as cracking, springback or dimensional instability during the cold forming process.

[0004] Therefore, it is necessary to design a chassis-mounted welding sleeve and a manufacturing method thereof to solve the problems existing in the current technology. Summary of the Invention

[0005] In view of this, the present invention proposes a chassis-mounted welding sleeve and a manufacturing method thereof, aiming to solve the problems of poor forming efficiency, poor product consistency and inability to guarantee product quality of the current welding sleeve.

[0006] On the one hand, the present invention proposes a manufacturing method for a chassis-mounted welding sleeve, including: Performing spheroidizing annealing on the wire rod and then performing primary drawing, performing secondary spheroidizing annealing and then performing secondary drawing to obtain a workpiece to be cold headed; Putting the workpiece to be cold headed into a multi-station cold heading forming machine for cold heading forming, straightening the wire rod through a first-order die, and using a punch rod to press the blank into the die forming hole to punch an integeration pit; using a second-order die to draw the inner hole, adjusting the diameter and length and adding a head chamfer die core; using a third-order die to stretch the rear hole to form a flange pre-profile; using a fourth-order die to extend the existing inner hole to reach the target depth; using a fifth-order die to form a straight cylinder, a welding groove and an exhaust groove; using a sixth-order die to punch through the center hole of the sleeve to form a through hole, and forming a workpiece to be finely processed; Performing inner hole turning on the workpiece to be finely processed based on a numerical control lathe to obtain a finely processed workpiece; Performing barrel plating on the finely processed workpiece to obtain a chassis-mounted welding sleeve.

[0007] Further, during cold heading forming, it includes: The strong beam ratio of the first-stage forming process is 14-16%; and / or, The upset ratio of the second-stage forming process is 11-15%; and / or, The upset ratio of the third-stage forming process is 6-8%; and / or, The upset ratio of the fourth-stage forming process is 7-10%; and / or, The upset ratio of the fifth-stage forming process is 2-5%.

[0008] Further, when using the sixth-stage die to punch through the center hole of the sleeve to form a through hole and form a workpiece to be finely processed, it includes: Based on the pressure sensor group, collect the pressure data at several locations of the sixth-stage die and establish a pressure data group; Take the pressure data at the same horizontal plane in the pressure data group as a data group to be processed and draw the data group to be processed as a two-dimensional pressure diagram; Arbitrarily determine a center point in the two-dimensional pressure diagram ( ); Determine the neighborhood range with the center point as the center and r as the neighborhood radius; Calculate the neighborhood average pressure according to the pressure data of each coordinate point within the neighborhood range; When the difference between the pressure data of the center point and the neighborhood average pressure is greater than the pressure difference threshold, determine that the coordinates of the center point are defect coordinate points, and the pressure difference threshold is a non-zero positive integer.

[0009] Further, the neighborhood average pressure is calculated by the following formula:

[0010] Wherein, represents the neighborhood average pressure, r represents the neighborhood radius, ( , ) represents the coordinates of the center point, represents the pressure data of the point on the two-dimensional pressure diagram.

[0011] Further, when using the sixth-stage die to punch through the center hole of the sleeve to form a through hole and form a workpiece to be finely processed, it further includes: When there are no defect coordinate points in all the data groups to be processed, take the workpiece after the sixth-stage forming as the workpiece to be finely processed; When there are defect coordinate points in any of the data groups to be processed, record the defect coordinate points. If the pressure data of the defect coordinate points is less than the die pressure limit, increase the cold heading pressure of the sixth-stage die; if the pressure data of the defect coordinate points is greater than or equal to the die pressure limit, give a cold heading pressure warning.

[0012] Further, after increasing the cold heading pressure of the six - sequence die, it further includes: Optically inspecting the workpiece after being formed by the six - sequence die, and the optical inspection includes: Placing the formed workpiece on a rotatable worktable, irradiating the formed workpiece based on parallel light, using a CCD camera to collect the light - blocking profile of the formed workpiece rotating one week, analyzing all the light - blocking profiles, and judging whether the formed workpiece is qualified according to the analysis result.

[0013] Further, when judging whether the formed workpiece is qualified according to the analysis result, it includes: When the similarity between all the light - blocking profiles and the standard light - blocking profile is greater than or equal to the similarity threshold, it is determined that the formed workpiece is qualified, and the formed workpiece is used as the workpiece to be finely processed; When there is a light - blocking profile whose similarity with the standard light - blocking profile is less than the similarity threshold, it is determined that the formed workpiece is unqualified, and an early warning of abnormal workpiece processing is given.

[0014] Further, after increasing the cold heading pressure of the six - sequence die, the optical inspection further includes: Placing the formed workpiece on a rotatable worktable, irradiating the formed workpiece along the axial direction of the formed workpiece based on a line laser group, the line laser group includes at least five line laser emitters, and the irradiation direction of the line laser has an inclination angle with the vertical cross - section of the formed workpiece. Based on the CCD camera, collecting the surface profile of the formed workpiece rotating one week, and judging whether the formed workpiece is qualified according to the length of the laser line in the surface profile.

[0015] Further, when judging whether the formed workpiece is qualified according to the length of the laser line in the surface profile, it includes: When the similarity between the laser line lengths at each structure of the formed workpiece and the standard laser line length is greater than or equal to the similarity threshold, it is determined that the formed workpiece is qualified, and the formed workpiece is used as the workpiece to be finely processed; When there is a laser line length whose similarity with the standard laser line length is less than the similarity threshold, it is determined that the formed workpiece is unqualified, and an early warning of abnormal workpiece processing is given.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: By sequentially performing spheroidizing annealing and drawing on the wire rod, the tissue properties and dimensional accuracy of the raw material are optimized, providing a stable foundation for subsequent cold heading processing, and improving the plasticity and crack resistance during the forming process; Subsequently, through a multi-station cold heading forming machine, integral forming of key structures such as profiling pit stamping, inner hole drawing, flange preforming, deep hole extension, straight cylinder and welding groove exhaust groove forming, and through hole punching is completed in sequence, avoiding the superposition of dimensional errors and process discontinuity problems in the traditional multi-step machining process, ensuring the consistency of the product structure and the degree of functional integration; On this basis, the inner hole is further precision machined by a numerical control lathe to improve the assembly accuracy, and the finished product is given good corrosion resistance through barrel plating treatment. Integrating multiple technical paths such as material quenching and tempering, cold forming, and precision post-treatment, improves the structural strength, welding quality, and service life of the sleeve, and reduces the manufacturing cost.

[0017] On the other hand, the present application also provides a chassis-mounted welding sleeve prepared by the above-mentioned chassis-mounted welding sleeve manufacturing method, including: Welding joints, including a straight cylinder welding joint and a flange welding joint; The flange welding joint adopts a flange structure, with a welding groove and a welding exhaust groove provided at the flange. A straight cylinder structure is provided under the flange head for interference fit with the lower welding plate; The straight cylinder welding joint is set with dimensional tolerances, and after interference fit with the upper welding plate, welding reinforcement is carried out; The transition area between the straight cylinder welding joint and the flange welding joint adopts a cold-formed integral forming structure; It also includes a counterbore structure provided at both the upper and lower ends; It also includes an internal thread structure.

[0018] It can be understood that the above-mentioned chassis-mounted welding sleeve and its manufacturing method have the same beneficial effects, which will not be elaborated here. Description of the Drawings

[0019] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings: Figure 1 It is a flowchart of the chassis-mounted welding sleeve manufacturing method provided by the embodiment of the present invention; Figure 2 It is a cold heading schematic diagram during the preparation of the chassis-mounted welding sleeve provided by the embodiment of the present invention; Figure 3 It is a structural schematic diagram of the chassis-mounted welding sleeve provided by the embodiment of the present invention.

[0020] Among them, 100 is the chassis-mounted welding sleeve; 110 is the straight cylinder welding joint; 120 is the flange welding joint; 121 is the welding groove; 122 is the welding exhaust groove; 130 is the counterbore; 140 is the internal thread. Detailed implementation manners

[0021] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be fully conveyed to those skilled in the art. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0022] In the traditional existing manufacturing process of welding sleeves, the material directly enters the cold heading process after simple annealing and single drawing, resulting in insufficient refinement of the grain structure. During the cold heading process, local stress concentration is caused by insufficient plasticity of the material, resulting in surface cracking or internal microcracks of the workpiece. During multi-station cold heading forming, the distribution of deformation amounts between the molds of each process lacks systematic control, resulting in insufficient stretching of the flange pre-profile or uneven wall thickness of the straight cylinder section, and subsequent turning correction is required, resulting in a decrease in material utilization rate and an extension of the processing cycle. In addition, the forming of the welding groove and the exhaust groove relies on multiple stamping processes. The mismatch between the stamping boundary conditions and the die parameters leads to fluctuations in the geometric accuracy of the groove, and gaps or misalignments are likely to occur during welding assembly.

[0023] For example, in the mass production of welding sleeves for new energy vehicle chassis, the wire rod is directly cold headed after ordinary annealing, and the annealing temperature and holding time are not dynamically adjusted according to the carbon content gradient of the wire rod, resulting in uneven hardness distribution of the material after annealing. During the straightening of the first cold heading process, due to insufficient release of the residual stress of the wire rod, the axis of the blank after straightening is offset, and the alignment between the die and the blank deteriorates during the subsequent deep hole drawing process, and the roundness of the deep hole exceeds the tolerance. When forming the welding groove in the fifth process, the punching rod pressure and the die gap are not optimized based on the material flow characteristics, resulting in wrinkles or material accumulation at the root of the groove, affecting the uniformity of the formation of the welding molten pool. After the sixth punching process, the surface roughness of the deep hole exceeds the allowable range of the turning allowance due to the aggravation of cold work hardening, and a polishing process needs to be added.

[0024] If the above problems are not solved, the micro-defects generated during the cold heading forming stage will be exposed during the subsequent turning process, resulting in a reduction in the bearing cross-sectional area of the sleeve, an expansion of the stress concentration area under dynamic loads, and a decrease in fatigue life. The geometric deviation between the welding groove and the exhaust groove will weaken the strength of the welded joint, initiate and propagate cracks in the vehicle vibration environment, and threaten the structural stability of the battery pack mounting. The increase in material loss and energy consumption caused by multi-process correction will increase the unit manufacturing cost and limit the economy of large-scale mass production.

[0025] When facing the above problems, this application first addresses the issue of cold heading cracking caused by insufficient plasticity and uneven grain structure of the wire rod. By optimizing the annealing and drawing processes, the formability of the material is improved. Traditional single annealing is difficult to eliminate carbon segregation and residual stress inside the wire rod. This application adopts secondary spheroidizing annealing combined with staged drawing. After the initial drawing, secondary annealing is carried out to refine the grains and balance the hardness and ductility of the material. For the problem of unreasonable deformation amount distribution in multi-station cold heading forming, the die processes are re-planned, and the flange pre-profile and the welding groove are formed in separate sequences to avoid excessive deformation in a single sequence causing wrinkles. At the same time, to solve the problem of insufficient inner hole forming accuracy, a six-pass progressive punching process is designed. By combining the extended hole depth and the sizing pit, the subsequent turning allowance is reduced.

[0026] In some embodiments of this application, referring to Figure 1-2 as shown, a method for manufacturing a chassis-mounted welded sleeve is proposed, including: S100: Perform spheroidizing annealing on the wire rod and then carry out the initial drawing. After secondary spheroidizing annealing, perform secondary drawing to obtain the workpiece to be cold headed; S200: Place the workpiece to be cold headed into a multi-station cold heading forming machine for cold heading forming. Straighten the wire rod through the first-order die, and use a punch rod to press the blank into the die forming hole to punch out the sizing pit; Use the second-order die to draw the inner hole, adjust the diameter and length, and add a head chamfer die insert; Use the third-order die to stretch the rear hole to form a flange pre-profile; Use the fourth-order die to extend the existing inner hole to reach the target depth; Use the fifth-order die to form the straight cylinder, welding groove, and exhaust groove; Use the sixth-order die to punch through the center hole of the sleeve to form a through hole, and form the workpiece to be finely processed; S300: Perform inner hole turning on the workpiece to be finely processed based on a numerically controlled lathe to obtain the finely processed workpiece; S400: Perform barrel plating on the finely processed workpiece to obtain the chassis-mounted welded sleeve.

[0027] Specifically, the spheroidizing annealing of wire rods refers to heating to the critical temperature and then slowly cooling to eliminate internal stress and improve the ductility of the material. It can be specifically achieved by using a continuous annealing furnace with segmented temperature control under nitrogen protection, reducing the risk of fracture during subsequent drawing processes. The first drawing and the second drawing refer to the plastic processing of gradually reducing the diameter of the wire through a die. It can be specifically achieved by using a roller die drawing machine in combination with a lubricant to ensure the diameter accuracy and surface quality of the wire. The multi-station cold heading forming machine refers to a forming device with continuous transfer stations and integrated multiple dies. It can be specifically achieved by using a six-station rotary press in combination with a servo drive system, reducing the single deformation amount through step-by-step forming in sequence. The first-order die straightening the wire rod refers to correcting the straightness of the wire. It can be specifically achieved by using a V-shaped straightening die and a backward extrusion process to eliminate the forming eccentricity caused by the bending of the wire rod. The punch pressing into the forming hole of the die to punch out the sizing pit refers to forming a positioning groove on the end face of the blank using a punch. It can be specifically achieved by using a conical punch in combination with a high-hardness die cavity to provide a centering reference for subsequent stations. The second-order die drawing the inner hole refers to forming the inner cavity of the sleeve through backward extrusion. It can be specifically achieved by using a stepped punch and a progressive diameter-expanding die to control the uniformity of the hole wall thickness. The third-order die stretching the rear hole to form a flange pre-profile refers to constructing the flange prototype through radial material flow. It can be specifically achieved by using a combined die core with an annular runner to reduce the stress concentration at the root of the flange. The fourth-order die extending the inner hole to the target depth refers to increasing the length of the inner hole through axial extrusion. It can be specifically achieved by using an extended punch with a limiting structure to ensure the depth tolerance of the inner hole. The fifth-order die forming the straight cylinder, welding groove, and exhaust groove refers to synchronously machining complex geometric features through multi-directional die splitting. It can be specifically achieved by using a split die cavity and a lateral slider structure to avoid the error caused by multiple clamping. The sixth-order die punching through the center hole to form a through hole refers to removing the residual material at the bottom to form a through hole. It can be specifically achieved by using a thimble-type blanking die to ensure that there is no burr at the hole opening. The internal hole turning of the CNC lathe refers to precision machining by programming the tool path. It can be specifically achieved by using a cemented carbide blade and a minimum quantity lubrication system to correct the dimensional deviation of the inner hole after cold heading forming. Barrel plating refers to electrolytically depositing a metal coating through a drum. It can be specifically achieved by using a zinc-nickel alloy electroplating solution and a pulse current process to improve the surface corrosion resistance of the sleeve.

[0028] It can be understood that through the process chain of combining spheroidizing annealing and sequential cold heading forming with CNC precision machining, the integrated and efficient forming of the sleeve structure is realized. The multi-station cold heading is used to step by step form the straight cylinder, flange, groove, and exhaust groove, reducing material loss and the number of processing steps; the grain structure of the material is optimized through drawing and annealing processes to avoid cold heading cracking; the dimensional deviation of cold heading is compensated by using CNC turning to ensure the inner hole accuracy and the requirements of interference fit for assembly.

[0029] The working process and principle of this application are as follows: First, spheroidizing annealing treatment is performed on the wire rod to eliminate internal stress in the material and improve the grain structure. After annealing, primary drawing is carried out to refine the grains and increase the material strength through plastic deformation. Subsequently, secondary spheroidizing annealing is performed to further optimize the material structure. After drawing again, a cold-heading workpiece with good plasticity and strength is obtained. The cold-heading workpiece is placed in a multi-station cold-heading forming machine for cold-heading forming. The first-order die straightens the wire rod and punches an integeration pit, laying a foundation for subsequent forming. The second-order die draws the inner hole and adjusts the size, and at the same time adds a head chamfer die insert. The third-order die forms a flange pre-profile after stretching the rear hole, preparing for the final flange structure. The fourth-order die further extends the inner hole to the target depth. The fifth-order die forms complex structures such as a straight cylinder, a welding groove, and an exhaust groove. The sixth-order die punches through the center hole of the sleeve to form a workpiece to be finely processed. The inner hole of the workpiece to be finely processed is turned by a CNC lathe to improve the inner hole precision and surface quality. Finally, the finely processed workpiece is barrel-plated to improve the surface performance and obtain a finished chassis-mounted welding sleeve. This process of multi-pass cold-heading forming combined with precision turning and surface treatment can effectively control the deformation amount in each forming stage, improve the product size precision and surface quality, and at the same time ensure the forming effect of complex structures.

[0030] As a preferred embodiment, the solution of this application is specifically implemented as follows: First, the wire rod is annealed in a spheroidizing annealing furnace. The annealing temperature is set at 700 - 750 °C, and the holding time is 2 - 3 hours. After annealing, primary drawing is carried out, and the drawing ratio is controlled between 1.2 - 1.5.

[0031] Secondary spheroidizing annealing is carried out, with the temperature set at 680 - 720 °C and the holding time of 1.5 - 2 hours. After drawing again, a cold-heading workpiece is obtained, and the final drawing ratio is controlled between 1.8 - 2.2.

[0032] The cold-heading workpiece is placed in a six-station cold-heading forming machine for cold-heading forming. The first-order die is made of cemented carbide material, and the inner cavity diameter of the die is slightly larger than the workpiece diameter. The punching rod pressure is set at 80 - 100 MPa, and the blank is pressed into the die forming hole to punch an integeration pit with a depth of 1 - 2 mm.

[0033] The second-order die is made of high-speed steel, and the drawing depth of the inner hole is 40 - 50% of the total length of the workpiece. The angle of the head chamfer die insert is set at 30 - 45°. The third-order die forms a flange pre-profile after stretching the rear hole, and the increase in the flange outer diameter is 10 - 20% of the original diameter.

[0034] The four - sequence die continues to extend the inner hole to the target depth. The five - sequence die forms the straight cylinder section and processes a welding groove and an exhaust groove with a width of 2 - 3 mm and a depth of 1 - 1.5 mm at the flange. The six - sequence die uses a cemented carbide punch, with a punching pressure of 120 - 150 MPa, to punch through the center hole of the sleeve to form a through - hole.

[0035] Use a CNC lathe to perform internal hole turning on the workpiece to be finish - machined. The turning feed rate is set to 0.1 - 0.2 mm / r, and the cutting depth is 0.2 - 0.5 mm. Finally, perform plating treatment on the finish - machined workpiece in a barrel plating equipment, and control the plating thickness within 5 - 10 μm.

[0036] It can be understood that this application can effectively improve the forming accuracy and surface quality of the chassis - mounted welding sleeve. The multi - pass cold heading forming process can control the deformation amount at each stage, reduce the accumulation of internal stress, and lower the risk of cracking. Precision turning and surface treatment further optimize the product performance, improve the dimensional accuracy, surface quality and structural strength of the welding sleeve, and meet the strict requirements of the battery pack mounting structure for the new energy vehicle chassis. At the same time, this process can improve the material utilization rate, reduce the machining allowance, and lower the manufacturing cost.

[0037] In some of the above - mentioned solutions of this application, during the multi - station cold heading forming process, the deformation amount of each sequence process is not properly controlled, resulting in uneven distribution of internal stress in the material, which easily causes cracking or dimensional deviation of the workpiece and affects the forming quality of the sleeve.

[0038] This application further proposes a method for manufacturing a chassis - mounted welding sleeve, including the following steps: the strong - beam ratio of the first - sequence forming process is 14 - 16%; the upsetting ratio of the second - sequence forming process is 11 - 15%; the upsetting ratio of the third - sequence forming process is 6 - 8%; the upsetting ratio of the fourth - sequence forming process is 7 - 10%; the upsetting ratio of the fifth - sequence forming process is 2 - 5%.

[0039] Among them, the strong - beam ratio is a quantitative parameter defined as the reduction ratio of the cross - sectional area during the wire rod straightening process, and the upsetting ratio characterizes the percentage of the axial compression deformation amount. The numerical range of the first - sequence strong - beam ratio avoids the generation of micro - cracks on the material surface by restricting the degree of plastic deformation in the initial straightening stage; the upsetting ratios of the second to fifth sequences are configured in a gradient - decreasing manner. By gradually reducing the deformation rate in stages, the metal grains flow orderly during the cold heading process, reducing local stress concentration. For example, the upsetting ratio of the second sequence is set to 11 - 15% to ensure the match between the material ductility and the die cavity during the inner - hole drawing; the third and fourth sequences correspond to the pre - contour forming of the flange and the inner - hole extension respectively, and their upsetting ratios are reduced to 6 - 10% to avoid excessive work hardening; the upsetting ratio of the fifth sequence is further controlled within 2 - 5% to maintain the structural accuracy when forming the straight cylinder and the welding groove.

[0040] Specifically, in the first-stage straightening process, when the strong beam ratio is lower than 14%, the straightening of the wire rod is insufficient, resulting in subsequent cold heading positioning deviation; if it exceeds 16%, scratches are likely to occur on the wire rod surface or internal crystal grains are broken. By limiting the strong beam ratio to 14 - 16%, both the bending stress of the wire rod can be eliminated and the material toughness can be retained. In the second-stage deep drawing of the inner hole, when the upsetting ratio is in the range of 11 - 15%, through the synergistic effect of axial compression and radial expansion, the inner hole diameter and length can reach the design values simultaneously, and the embedding angle of the head chamfer die core is adapted to the upsetting deformation amount to avoid wrinkles on the hole wall. In the third-stage flange pre-profile forming process, an upsetting ratio of 6 - 8% enables the material to flow in layers within the die, forming a uniform flange thickness gradient; in the fourth-stage inner hole extension, an upsetting ratio of 7 - 10% is used, and by adjusting the punch pressure and die clearance, the hole depth can be increased while maintaining the inner wall finish. When forming the straight cylinder in the fifth stage, an upsetting ratio of 2 - 5% is combined with a multi-stage ejection mechanism to ensure that the geometric accuracy of the welding groove and exhaust groove is controlled within ±0.02 mm. The process parameters of each stage are used to adjust the punching pressure and stroke speed in real time through the servo system of the cold heading machine to achieve dynamic matching of the deformation amount, and finally the material utilization rate of the sleeve forming process is increased to more than 92% without cracking defects.

[0041] As a preferred embodiment, the solution of the present application is specifically implemented as follows: During cold heading forming, the strong beam ratio of the first-stage forming process is 15%; the upsetting ratio of the second-stage forming process is 13%; the upsetting ratio of the third-stage forming process is 7%; the upsetting ratio of the fourth-stage forming process is 8%; the upsetting ratio of the fifth-stage forming process is 3%.

[0042] Through the above technical solution, the present application realizes the optimal configuration of the process parameters of each stage during cold heading forming. While ensuring the forming quality, the production efficiency is improved and material waste is reduced. Further, by reasonably controlling the strong beam ratio and upsetting ratio of each stage of the forming process, quality problems such as cracking and springback of the workpiece during the forming process are avoided, and the dimensional accuracy and surface quality of the product are improved.

[0043] In some of the above solutions of the present application, when forming the central through hole of the sleeve by the cold heading forming process, uneven pressure distribution inside the die may cause local defects of the workpiece, such as material accumulation or cracks, affecting the quality of subsequent finishing and the reliability of the finished product.

[0044] The present application further proposes to collect pressure data at several locations of a six - sequence die based on a pressure sensor group, and establish a pressure data group; take the pressure data at the same horizontal plane in the pressure data group as a data group to be processed and draw the data group to be processed as a two - dimensional pressure map; arbitrarily determine a center point in the two - dimensional pressure map; determine a neighborhood range with the center point as the center and r as the neighborhood radius; calculate the neighborhood average pressure according to the pressure data of each coordinate point within the neighborhood range; when the difference between the pressure data of the center point and the neighborhood average pressure is greater than the pressure difference threshold, determine that the coordinates of the center point are defect coordinate points, and the pressure difference threshold is a non - zero positive integer.

[0045] Among them, the pressure sensor group is embedded in multiple key stress - bearing areas of the six - sequence die, such as the die ejector rod, the side wall of the forming hole, and the pre - contour contact surface of the flange. The construction of the two - dimensional pressure map is based on the superposition mapping of pressure data on the same axial section. The coordinates of the center point can be determined randomly or based on the geometric symmetry center of the die. The value of the neighborhood radius r is in a proportional relationship with the die size. For example, 5% - 8% of the die diameter is taken. The setting of the pressure difference threshold is based on the dynamic matching of the material yield strength and the die load - bearing limit. For example, 0.5% - 1.2% of the material elastic modulus is used as the reference value.

[0046] Specifically, when the six - sequence die performs the forming of the sleeve center hole, the pressure sensors collect the dynamic pressure data at different positions of the die in real - time. The pressure data at the same horizontal plane form a two - dimensional pressure distribution map after coordinate transformation. By selecting the center point and calculating its neighborhood average pressure, local pressure abnormal areas can be identified. When the difference between the center point pressure and the neighborhood average pressure exceeds the threshold, it indicates that there are stress concentration or material flow defects in this area. By adjusting the cold - heading pressure or triggering the warning mechanism, the expansion of defects can be avoided. For example, when the pressure at the defect point is lower than the die pressure limit, the cold - heading pressure is automatically increased to compensate for insufficient material filling; when the pressure exceeds the limit, the processing flow is immediately interrupted and the die is prompted for maintenance. This process realizes the real - time monitoring and active control of forming defects, effectively reducing the defective rate. As a preferred embodiment, the solution of the present application is specifically implemented as follows: Collect pressure data at several locations of a six - sequence die based on a pressure sensor group, and establish a pressure data group. The pressure sensor group includes multiple pressure sensors, which are evenly distributed at key positions of the six - sequence die. Each pressure sensor collects the pressure data at its location in real - time and transmits the data to the central processing unit. The central processing unit receives the data of all pressure sensors and integrates these data into a pressure data group.

[0047] Take the pressure data at the same horizontal plane in the pressure data group as a data group to be processed and plot the data group to be processed as a two-dimensional pressure map. Specifically, select the pressure data at the same horizontal plane on the six-sequence die, and take these data as a data group to be processed. Using computer drawing software, represent the position of the pressure sensor on the horizontal plane with x and y coordinates, and represent the pressure magnitude with the depth of color or height to generate a two-dimensional pressure map.

[0048] Arbitrarily determine a center point in the two-dimensional pressure map. For example, the central position of the pressure map can be selected as the center point, or an area with a higher pressure value can be selected as the center point.

[0049] Determine the neighborhood range with the center point as the center and r as the neighborhood radius. The neighborhood radius r can be adjusted according to the die size and pressure distribution characteristics to ensure that the neighborhood range can represent the local pressure distribution.

[0050] Calculate the neighborhood average pressure according to the pressure data of each coordinate point within the neighborhood range. Specifically, extract the values of all pressure data points within the neighborhood range and calculate the arithmetic mean of these data points to obtain the neighborhood average pressure.

[0051] When the difference between the pressure data of the center point and the neighborhood average pressure is greater than the pressure difference threshold, determine that the coordinates of the center point are defective coordinate points. The pressure difference threshold is a positive integer other than zero. For example, the pressure difference threshold can be set to 5 MPa. If the difference between the center point pressure and the neighborhood average pressure exceeds 5 MPa, then determine that the center point is a defective coordinate point.

[0052] Through the above technical solutions, the present application can effectively detect pressure anomalies during the forming process of the six-sequence die. Thereby improving the forming quality and consistency of the chassis-mounted welding sleeve. Further, this method can timely discover the problem of uneven pressure distribution in the die, avoiding workpiece defects caused by excessive or too small local pressure. Specifically, by analyzing the two-dimensional pressure map and calculating the neighborhood average pressure, pressure anomaly points can be accurately identified, thereby guiding the adjustment of cold heading pressure or giving early warnings. The quality control method based on data analysis improves the manufacturing accuracy and reliability of the chassis-mounted welding sleeve.

[0053] In some of the above solutions of the present application, when using the pressure data group for defect detection, it is necessary to calculate the neighborhood average pressure to determine whether there are defects at the center point. However, due to the possible non-linear variation of the pressure distribution at each point on the two-dimensional pressure map, it is difficult to accurately reflect the true pressure distribution within the neighborhood using the simple arithmetic mean method, resulting in misjudgment or missed judgment of defective coordinate points.

[0054] The present application further proposes that the neighborhood average pressure is obtained by calculating through the following formula:

[0055] Among them, represents the neighborhood average pressure, r represents the neighborhood radius, and ( , ) represents the coordinates of the center point, represents the pressure data of the point on the two-dimensional pressure map .

[0056] Among them, the neighborhood range is a circular area defined by a circle with the center point coordinates as the center and a radius of r, covering all discrete pressure points within this area. The pressure data is distributed in the form of two-dimensional coordinates on the pressure map, and each coordinate point corresponds to the real-time pressure value collected by the pressure sensor group. During the calculation process, the values of all pressure points within the neighborhood are integrated and summed, and then divided by the neighborhood area to obtain the average pressure per unit area. The integration range covers the x-axis range from to and the y-axis range from to, ensuring that all pressure points within the neighborhood are included in the calculation.

[0057] Specifically, through integral operations, the pressure distribution within the neighborhood is continuously processed to eliminate the calculation deviation caused by the spacing of discrete data points. For example, when r is set to 2 mm, the integration process covers a circular area with a diameter of 4 mm around the center point, and the pressure values within the area are weighted and summed to accurately reflect the pressure distribution trend. During the calculation, if there are pressure mutation points within the neighborhood, the integration result will significantly reflect the impact of this mutation on the average pressure. Further, by standardizing the calculation process, the errors caused by manual experience intervention are avoided, ensuring the consistency of the calculation results when executed by different batches or different operators. Thus, the determination criterion for defect coordinate points has higher objectivity and repeatability, effectively improving the accuracy of quality inspection during the six-sequence mold forming process.

[0058] As a preferred embodiment, the solution of the present application is specifically implemented as follows: When calculating the neighborhood average pressure, first determine a neighborhood radius r. For example, 5 mm can be selected as the neighborhood radius. Then, with the selected center point (x0, y0) as the center and r as the radius, draw a circle, and sum up the pressure values of all pressure data points within this circle. Finally, divide the summation result by the total number of pressure data points within the neighborhood to obtain the neighborhood average pressure value of this center point.

[0059] Furthermore, in order to improve the calculation accuracy, an interpolation method can be used to process the pressure data within the neighborhood. For example, the bilinear interpolation method can be used to calculate the pressure value at any position within the circle based on the neighboring known pressure data points. This can more accurately reflect the pressure distribution within the neighborhood.

[0060] Thus, by calculating the neighborhood average pressure, the influence of random fluctuations of individual pressure data points can be effectively eliminated, and a more stable and reliable pressure evaluation result can be obtained. This provides an important basis for subsequent judgment of defect coordinate points.

[0061] Through the above technical solutions, the present application can accurately calculate the neighborhood average pressure of any center point in the two-dimensional pressure map. By comparing the center point pressure with the neighborhood average pressure, pressure anomaly points can be effectively identified, thereby timely detecting potential defects in the cold heading forming process. This method not only improves the accuracy of defect detection but also enables real-time monitoring of the cold heading process, contributing to the improvement of product quality and production efficiency.

[0062] In some of the above solutions of the present application, it is determined whether the cold heading forming process meets the requirements based on pressure data, and the cold heading pressure is adjusted based on the determination result. However, the actual forming state of the workpiece still needs to be verified after the cold heading pressure is adjusted. If the forming effect after adjustment is not subjected to secondary detection, local deformation defects may remain undetected, resulting in the accumulation of machining errors in subsequent processes.

[0063] The present application further proposes a step of optically detecting the formed workpiece after increasing the cold heading pressure. This optical detection step includes: placing the formed workpiece on a rotatable workbench, irradiating the formed workpiece with parallel light, using a CCD camera to collect the light-blocking profile of the formed workpiece rotating one week, analyzing all the light-blocking profiles, and judging whether the formed workpiece is qualified according to the analysis result.

[0064] Among them, the rotatable workbench is driven by a servo motor, and its rotation angle accuracy is controlled within the range of ±0.1 degrees. The light source wavelength range of the parallel light is set to 400 - 700 nanometers, and the beam divergence angle is less than 0.5 degrees. The pixel resolution of the CCD camera is not less than 12 million, and the frame rate is set to 60 frames per second. The light-blocking profile analysis extracts edge features through a gray-scale image processing algorithm and performs point-by-point matching with the standard profile. The similarity threshold is set to 98%. When the similarity of the light-blocking profile at any angle is lower than this threshold, an early warning of abnormal workpiece processing is triggered.

[0065] Specifically, the formed workpiece rotates at a constant angular velocity driven by the rotatable workbench, and the parallel light is projected along the axis of the workpiece to form an illumination plane perpendicular to the workpiece surface. The CCD camera captures the projection profile during the rotation of the workpiece at a fixed frequency to generate a sequence of light-blocking images of consecutive frames. The image processing system sharpens the edges and eliminates noise for each frame of the image, and extracts the contour line coordinate data. The actual contour and the standard contour are transformed to the frequency domain through Fourier transform, and the similarity of the energy distribution in the low-frequency band between the two is calculated. If the contour similarity at each angle reaches the threshold, it indicates that the increased cold heading pressure has effectively eliminated the forming defects; if there are abnormal contours lower than the threshold, it is determined that the pressure adjustment strategy fails and the processing flow needs to be terminated. This detection method can complete the full-circle detection of the workpiece within 0.5 seconds through non-contact optical measurement, avoiding secondary damage caused by mechanical contact.

[0066] As a preferred embodiment, the solution of the present application is specifically implemented as follows: When there are no defective coordinate points in all the data groups to be processed, the workpiece after six-sequence forming is used as the workpiece to be finish-machined.

[0067] When there are defective coordinate points in any of the data groups to be processed, record the defective coordinate points. If the pressure data of the defective coordinate points is less than the die pressure limit, increase the cold heading pressure of the six-sequence die upward. If the pressure data of the defective coordinate points is greater than or equal to the die pressure limit, give a cold heading pressure warning.

[0068] Specifically, during the process of the six-sequence die punching through the sleeve center hole to form a through hole, first collect the pressure data at multiple positions of the six-sequence die and establish a pressure data group. Take the pressure data on the same horizontal plane as the data group to be processed and draw it as a two-dimensional pressure diagram. Determine a center point in the two-dimensional pressure diagram, and determine the neighborhood range with the center point as the center and a preset neighborhood radius. Calculate the average pressure of each coordinate point within the neighborhood range. When the difference between the center point pressure data and the neighborhood average pressure is greater than the preset pressure difference threshold, determine that the center point coordinate is a defective coordinate point.

[0069] Furthermore, analyze all the data groups to be processed. If there are no defective coordinate points, directly use the workpiece after six-sequence forming as the workpiece to be finish-machined. If there are defective coordinate points, record the defective coordinate points. Thus, according to the comparison result between the pressure data of the defective coordinate points and the die pressure limit, decide whether to increase the cold heading pressure or give a pressure warning.

[0070] Through the above technical solution, the present application can monitor the pressure distribution during the forming process of the six-sequence die in real time, discover and locate the forming defects in time. According to the pressure data at the defective position, the cold heading pressure can be adjusted adaptively or a warning can be given to avoid producing unqualified workpieces. This method improves the stability of the forming process and the quality of the workpiece, reduces the rework and scrapping in the subsequent processing links, and thus improves the production efficiency and material utilization rate.

[0071] In some of the above solutions of the present application, there is a lack of effective means to verify the quality of the formed workpiece after the cold heading pressure is adjusted. It may lead to abnormal internal structure of the workpiece or surface defects not being discovered in time due to the change of pressure parameters, affecting the subsequent assembly accuracy and welding strength.

[0072] The present application further proposes to perform optical inspection on the workpiece after six-sequence die forming, including placing the formed workpiece on a rotatable workbench, irradiating the formed workpiece with parallel light, using a CCD camera to collect the light-blocking contour of the formed workpiece rotating one week, analyzing all the light-blocking contours, and judging whether the formed workpiece is qualified according to the analysis result.

[0073] Among them, the rotatable workbench is driven by a servo motor and can achieve precise indexing rotation of 360 degrees; the parallel light generator is arranged on the side of the workbench, and the optical axis direction is perpendicular to the axis of the workpiece; the CCD camera is equipped with a high-resolution industrial lens and collects contour images at a rate of 50 frames per second. The light-blocking contour analysis uses an image gray-scale contrast algorithm to perform point cloud matching between the contour edge coordinates collected in real time and the standard contour coordinates.

[0074] Specifically, after the formed workpiece is fixed to the workbench fixture, it starts to rotate, and image acquisition is triggered every 1-degree rotation. When the parallel light penetrates the workpiece, the CCD camera captures the projection contour of the workpiece's outer shape, generating a set of light-blocking contour data for continuous cross-sections. After all the contour data is filtered and noise-reduced, the similarity is evaluated by calculating the root mean square error value between each contour and the standard template. For example, when the error of the flange pre-contour exceeds 0.05 mm, it is determined that there is deformation in this area. If the error values of three consecutive cross-sections exceed the threshold, a warning signal is triggered and the production line is paused. This detection process is completed within 20 seconds, covering the geometric features of the entire circumferential direction of the workpiece, and effectively identifying the ellipticity deviation or axial bending defect generated after the cold heading pressure is adjusted.

[0075] As a preferred embodiment, the solution of the present application is specifically implemented as follows: After the cold heading pressure of the six-sequence die is increased upward, it also includes optical detection of the workpiece formed by the six-sequence die. The optical detection includes the following steps: First, place the formed workpiece on the rotatable workbench. The workbench is driven by a precision motor and can achieve 360-degree rotation, and the rotation accuracy reaches 0.1 degree.

[0076] Second, irradiate the formed workpiece with a parallel light source. The parallel light source uses an LED array, the light intensity is adjustable, and the wavelength range is 400 - 700 nm.

[0077] Then, use a CCD camera to collect the light-blocking contour of the formed workpiece rotating one week. The resolution of the CCD camera is 1920x1080 pixels, and the sampling frequency is 60 Hz.

[0078] Finally, analyze all the light-blocking contours, and judge whether the formed workpiece is qualified according to the analysis results. The analysis process uses image processing algorithms, including steps such as edge detection, contour extraction, and shape matching.

[0079] Through the above technical solution, the present application realizes the all-round optical inspection of the workpiece after the six-sequence mold is formed. Thus, defects in the forming process can be detected in a timely manner, improving the accuracy and efficiency of product quality control. Further, this method does not require manual intervention, can achieve automated inspection, reduces human error, and improves the consistency and reliability of inspection. Specifically, by collecting the light-blocking profile of the workpiece rotating one week, the geometric features of the workpiece surface can be comprehensively captured, including complex structures such as welding grooves and exhaust grooves, so as to realize the accurate evaluation of the overall shape of the workpiece.

[0080] In some of the above solutions of the present application, the optical inspection of the formed workpiece after the cold heading pressure is adjusted only judges the qualification of the workpiece through a single inspection method, which may lead to local defects or dimensional deviations not being effectively identified, thereby affecting the sleeve assembly accuracy and structural strength.

[0081] The present application further proposes that when the similarity between all the light-blocking profiles and the standard light-blocking profile is greater than or equal to the similarity threshold, it is determined that the formed workpiece is qualified, and the formed workpiece is used as a workpiece to be finely processed; when there is a light-blocking profile whose similarity to the standard light-blocking profile is less than the similarity threshold, it is determined that the formed workpiece is unqualified, and an early warning of abnormal workpiece processing is given.

[0082] Among them, the light-blocking profile is obtained by irradiating the rotating workpiece with parallel light and collecting it by a CCD camera, covering the entire circumferential surface morphology of the workpiece; the similarity threshold is set to be not less than 95%, and an image matching algorithm is used to calculate the coincidence degree between the actual light-blocking profile and the standard profile; after the warning signal is triggered, the production line is automatically paused and the position of the abnormal workpiece is marked.

[0083] Specifically, after the formed workpiece is placed on the rotatable workbench, the parallel light source projects axially to form uniform illumination, and the CCD camera captures the projection profile of the workpiece edge during rotation at a fixed frame rate. After the light-blocking profile data is preprocessed, it is compared point by point with the pre-stored standard profile, and the similarity is comprehensively evaluated by calculating the pixel coincidence degree and the curvature matching degree. When the similarity of any cross-section is lower than the threshold, it is determined that there is structural deformation or processing error, and the system immediately issues a warning and records the abnormal position, which is convenient for quickly locating the defect area. This determination mechanism avoids the subjective error of manual visual inspection by quantifying the contour matching degree, ensuring that the internal and external dimensions of the sleeve strictly meet the design tolerance requirements.

[0084] As a preferred embodiment, the solution of the present application is specifically implemented as follows: When the similarity between all the light-blocking profiles and the standard light-blocking profile is greater than or equal to the similarity threshold, it is determined that the formed workpiece is qualified, and the formed workpiece is used as a workpiece to be finely processed.

[0085] When there is a light-blocking profile whose similarity to the standard light-blocking profile is less than the similarity threshold, it is determined that the formed workpiece is unqualified, and an early warning of abnormal workpiece processing is given.

[0086] Specifically, the similarity threshold can be set to 0.95. First, place the formed workpiece on a rotatable workbench and irradiate the formed workpiece with a parallel light source. Then, use a CCD camera to collect the light-blocking contour images of the formed workpiece rotating one week. Next, compare each collected light-blocking contour image with the pre-stored standard light-blocking contour image and calculate the similarity. If the similarity of all collected light-blocking contour images to the standard image is greater than or equal to 0.95, it is determined that the formed workpiece is qualified and can enter the next fine machining process. Conversely, if the similarity of any one light-blocking contour image to the standard image is less than 0.95, it is determined that the formed workpiece is unqualified, and the system will issue a warning signal for abnormal workpiece processing to prompt the operator to check and handle it.

[0087] Through the above technical solution, the present application can quickly and accurately determine whether the formed workpiece is qualified. Thus, unqualified workpieces can be discovered and excluded in time to prevent them from entering the subsequent processing links, improving the efficiency and accuracy of product quality control. At the same time, by setting the similarity threshold, the judgment standard can be flexibly adjusted to adapt to the quality requirements of different products. In addition, by adopting an optical detection method, there is no need to contact the surface of the workpiece, which can reduce the damage to the workpiece and ensure that the detection process does not affect the quality of the workpiece.

[0088] In some of the above solutions of the present application, based on the detection method of analyzing the light-blocking contour by irradiating the formed workpiece with parallel light, in a strong light environment, it is easy to cause the contour boundary to be unclear, thus affecting the accuracy of the final workpiece quality judgment.

[0089] The present application further proposes to place the formed workpiece in a rotatable workbench and irradiate the formed workpiece along the axial direction of the formed workpiece based on a line laser group. The line laser group includes at least five line laser emitters, and the irradiation direction of the line laser has an inclination angle with the vertical cross-section of the formed workpiece. Based on the CCD camera, collect the surface contour of the formed workpiece rotating one week, and judge whether the formed workpiece is qualified according to the length of the laser line in the surface contour.

[0090] Among them, the line laser group is arranged by multiple emitters at different inclination angles to cover each area of the workpiece axially, and a detection network is formed through multi-beam projection. The five line laser emitters are arranged in the same plane and not directly facing the formed workpiece, and the inclination angle is controlled within the range of 5° to 15°, so that the laser line forms a bright vertical line on the workpiece surface, and there is an inflection point between the light at non-workpiece surfaces and the light at the workpiece surface, which is convenient for identifying the light boundary. The CCD camera synchronously collects the laser line deformation data during the rotation process at a high frame rate to construct the surface line segment data.

[0091] Specifically, after the formed workpiece is fixed on the rotating worktable, each line laser emitter projects a light beam towards the axis of the workpiece at a preset tilt angle. Every time the workpiece rotates a micro angle, the line laser forms a dynamically changing broken-line reflection image at the straight tube welding joint, flange welding joint and transition area. The CCD camera records the laser line length data at each angle, and identifies the surface dimension data of the workpiece by comparing with the reference laser line length distribution curve of the standard workpiece. When the deviation of the laser line length at any structure from the standard curve exceeds ±0.05 mm, an abnormal warning for workpiece processing is automatically triggered, and the difference data of the defect position is output synchronously. The misjudgment risk of a single detection method is effectively eliminated, and the full-process quality control ability of high-precision cold-heading workpieces is improved.

[0092] As a preferred embodiment, the solution of the present application is specifically implemented as follows: after the cold-heading pressure is adjusted, the formed workpiece is placed on the rotatable worktable, and five line laser emitters are used to project laser beams along the axis of the workpiece, and each line laser forms a 5-degree tilt angle with the vertical cross-section of the workpiece. The CCD camera synchronously collects the laser lines reflected from the surface during the 360-degree rotation of the workpiece. By comparing the laser line lengths at each structural part with the preset standard values, if the deviation of the laser line length exceeds ±0.1 mm, an abnormal warning for processing is triggered, and the unqualified workpieces are automatically sorted to the repair station.

[0093] Through the above technical solution, due to the problem that it is difficult to comprehensively detect the surface topography of the workpiece only by analyzing the light-shielding contour after the cold-heading pressure is adjusted in a strong light environment, local depressions or protrusions on the workpiece are not effectively identified, affecting the subsequent welding and assembly accuracy. The present application effectively solves the problem of surface feature detection. By combining inclined laser projection and rotary scanning, deformation monitoring is realized, avoiding misjudgment caused by structural shielding in traditional detection, ensuring that the deformation of the workpiece after cold-heading pressure adjustment is controlled within the welding and assembly tolerance range, and reducing the risks of false soldering and stress concentration in the subsequent welding process.

[0094] In the above embodiment, the wire rod is sequentially subjected to spheroidizing annealing and drawing treatments, optimizing the tissue properties and dimensional accuracy of the raw material, providing a stable basis for subsequent cold-heading processing, and improving the plasticity and crack resistance during the forming process; then, through a multi-station cold-heading forming machine, integral forming of key structures such as sizing pit stamping, inner hole drawing, flange pre-forming, deep hole extension, straight tube and welding groove exhaust groove forming, and through hole punching is sequentially completed, avoiding the problems of dimensional error superposition and process discontinuity in the traditional multi-channel machining process, and ensuring the consistency of product structure and functional integration; on this basis, the assembly accuracy is further improved by precision machining the inner hole with a numerical control lathe, and the finished product is given good corrosion resistance through barrel plating treatment. Integrating multiple technical paths such as material quenching and tempering, cold forming and precision post-treatment, improves the structural strength, welding quality and service life of the sleeve, and reduces the manufacturing cost.

[0095] In another preferred embodiment based on the above embodiments, refer to Figure 3 As shown, this embodiment provides a chassis-mounted welding sleeve, which is prepared by applying the above-mentioned method for manufacturing a chassis-mounted welding sleeve, and includes: The welding part includes a straight cylinder welding part 110 and a flange welding part 120; the flange welding part 120 adopts a flange structure, and there are a welding groove 121 and a welding exhaust groove 122 at the flange. A straight cylinder structure is arranged under the flange head for interference fit with the lower welding plate; the straight cylinder welding part 110 is provided with dimensional tolerances, and after interference fit with the upper welding plate, welding reinforcement is carried out; The transition area between the straight cylinder welding part 110 and the flange welding part 120 adopts a cold-forming integral forming structure; It also includes a counterbore 130 structure, which is arranged at the upper and lower ends; It also includes an internal thread 140 structure.

[0096] Specifically, the welding groove 121 of the flange welding part 120 is used to accommodate the weld metal, and the welding exhaust groove 122 can discharge the gas generated during the welding process to avoid porosity defects. The interference fit design of the straight cylinder welding part 110 and the flange welding part 120 is controlled by dimensional tolerances, ensuring that welding reinforcement can be carried out without secondary trimming after assembly. The cold-forming integral forming structure directly forms the transition area through a multi-station cold heading process, reducing the residual stress caused by split welding. The counterbore 130 structure facilitates the embedding of the bolt head; the internal thread 140 structure is formed by precision machining on a CNC lathe, and the thread accuracy meets the requirements of high-torque assembly.

[0097] Specifically, the flange welding part 120 is provided with a welding groove 121 and a welding exhaust groove 122. During the welding process after interference fit, the molten metal fills the groove, and the exhaust groove releases the welding gas to form a dense weld. The straight cylinder welding part 110 is welded and reinforced after interference fit with the upper welding plate, and its dimensional tolerance is controlled within ±0.02 mm to ensure the assembly accuracy. The transition area is integrally formed by the cold heading process, eliminating the weakening of material strength caused by traditional welding or machining. The depth of the counterbore 130 structure is 1.5 mm, which matches the height of the bolt head. The internal thread 140 structure adopts the M12×1.75 specification, the thread profile is machined by CNC turning, and the pitch error is less than 0.01 mm to ensure the meshing stability with the bolt.

[0098] As a preferred embodiment, the solution of the present application is specifically implemented as follows: The welding sleeve includes a straight barrel welding part 110 and a flange welding part 120. The flange welding part 120 adopts an annular flange structure, and a U-shaped groove with a depth of 1.2 mm is opened on its outer edge. Three trapezoidal exhaust channels with a width of 0.5 mm are distributed at intervals at the bottom of the groove. A cylindrical straight barrel with an axial length of 12 mm extends below the flange part, and an interference fit of 0.05 mm is formed between the outer diameter of the straight barrel and the mounting hole of the lower welding plate of the chassis. A closing structure with a taper of 1:50 is provided at the top of the straight barrel welding part 110, and after an interference fit with the upper welding plate, it is strengthened by laser welding. The connection area between the straight barrel part and the flange part adopts a continuous gradually changing wall thickness design, and through the cold heading process, the wall thickness of this area smoothly transitions from 3 mm to 5 mm. Step counterbores with a depth of 8 mm are machined on the inner walls at both ends of the sleeve, and an internal thread structure of M12×1.75 is provided at the bottom of the counterbores, and the effective screwing length of the thread reaches 6 mm.

[0099] Through the above technical solution, the present application realizes the stress optimization distribution and assembly precision control of the welded joint. The groove structure at the flange welding part effectively accommodates the weld metal, and the exhaust channels avoid the generation of welding bubbles. The interference fit design of the straight barrel part eliminates the assembly gap. The cold-formed integral structure eliminates the stress concentration problem of traditional welded joints. The combined design of the counterbore and the internal thread meets the assembly requirements of bolts of different specifications and reduces the use of auxiliary positioning tooling. When the welding sleeve bears an axial load, the stress is evenly transmitted to the flange part through the gradually changing wall thickness area, significantly improving the anti-fatigue performance of the connection node.

[0100] Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0101] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowcharts and / or block diagrams can be implemented by computer program instructions, and the combination of the processes and / or blocks in the flowcharts and / or block diagrams can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate for implementing in the process Figure 1 one process or multiple processes and / or blocks Figure 1a device for the functions specified in one or more boxes.

[0102] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory produce a manufactured article including an instruction device that implements the functions specified in one Figure 1 process or more processes and / or boxes Figure 1 a box or more boxes.

[0103] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one Figure 1 process or more processes and / or boxes Figure 1 a box or more boxes.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent replacements can still be made to the specific implementation manners of the present invention. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A method for manufacturing a chassis-mounted welding sleeve, characterized in that, Including: The wire rod is spheroidized and annealed and then subjected to primary drawing, and after secondary spheroidizing annealing, it is subjected to secondary drawing to obtain the workpiece to be cold - headed. The workpiece to be cold - headed is placed in a multi - station cold - heading forming machine for cold - heading forming. The wire rod is straightened by the first - order die, and a punch rod is used to press the blank into the forming hole of the die to punch an integer - shaping pit. The inner hole is drawn by the second - order die, the diameter and length are adjusted, and a head - type chamfering die core is added. The rear hole is stretched by the third - order die to form a flange pre - contour. The existing inner hole is extended by the fourth - order die to reach the target depth. The straight cylinder, welding groove and exhaust groove are formed by the fifth - order die. The central hole of the sleeve is drilled through by the sixth - order die to form a through - hole and form the workpiece to be finely processed. Based on a numerically controlled lathe, the inner hole of the workpiece to be finely processed is turned to obtain a finely processed workpiece. The finely processed workpiece is barrel - plated to obtain a chassis - mounted welding sleeve.

2. The method for manufacturing a chassis-mounted welding sleeve according to claim 1, characterized in that, When cold - heading forming, it includes: The strong - beam ratio of the first - order forming process is 14 - 16%; and / or The upsetting ratio of the second - order forming process is 11 - 15%; and / or The upsetting ratio of the third - order forming process is 6 - 8%; and / or The upsetting ratio of the fourth - order forming process is 7 - 10%; and / or The upsetting ratio of the fifth - order forming process is 2 - 5%.

3. The method for manufacturing a chassis-mounted welding sleeve according to claim 1, characterized in that, When using the sixth - order die to drill through the central hole of the sleeve to form a through - hole and form the workpiece to be finely processed, it includes: Based on a pressure sensor group, pressure data at several locations of the sixth - order die are collected to establish a pressure data group. The pressure data at the same horizontal plane in the pressure data group are used as a data group to be processed, and the data group to be processed is plotted as a two - dimensional pressure map. Arbitrarily determine a center point in the two-dimensional pressure diagram ( ); Taking the center point as the center of the circle and r as the neighborhood radius to determine the neighborhood range. Calculating the neighborhood average pressure according to the pressure data of each coordinate point within the neighborhood range. When the difference between the pressure data of the center point and the neighborhood average pressure is greater than the pressure difference threshold, the coordinate of the center point is determined as a defect coordinate point, and the pressure difference threshold is a non - zero positive integer.

4. The method for manufacturing a chassis-mounted welding sleeve according to claim 3, characterized in that, The neighborhood average pressure is calculated by the following formula: ； Among them, represents the neighborhood average pressure, r represents the neighborhood radius, ( , ) represents the coordinates of the center point, represents the pressure data of the point on the two-dimensional pressure map .

5. The method for manufacturing a chassis-mounted welding sleeve according to claim 4, characterized in that, When using the sixth - order die to drill through the central hole of the sleeve to form a through - hole and form the workpiece to be finely processed, it also includes: When there are no defect coordinate points in all the data groups to be processed, the workpiece after the sixth - order forming is used as the workpiece to be finely processed. When there are defect coordinate points in any of the data groups to be processed, the defect coordinate points are recorded. If the pressure data of the defect coordinate points is less than the die pressure limit, the cold - heading pressure of the sixth - order die is increased upward. If the pressure data of the defect coordinate points is greater than or equal to the die pressure limit, a cold - heading pressure warning is given.

6. The method for manufacturing a chassis-mounted welding sleeve according to claim 5, characterized in that, After the cold - heading pressure of the sixth - order die is increased upward, it also includes: Optical inspection is carried out on the workpiece after the sixth - order die forming. The optical inspection includes: The formed workpiece is placed on a rotatable workbench. Based on parallel light irradiating the formed workpiece, a CCD camera is used to collect the light - blocking contour of the formed workpiece rotating one week, and all the light - blocking contours are analyzed. According to the analysis result, it is judged whether the formed workpiece is qualified.

7. The method for manufacturing a chassis-mounted welding sleeve according to claim 6, characterized in that, When judging whether the formed workpiece is qualified according to the analysis result, it includes: When the similarity between all the light-blocking profiles and the standard light-blocking profile is greater than or equal to the similarity threshold, it is determined that the formed workpiece is qualified, and the formed workpiece is used as the workpiece to be finish-machined; When there is a similarity between a light-blocking profile and the standard light-blocking profile that is less than the similarity threshold, it is determined that the formed workpiece is unqualified, and an abnormal warning for workpiece processing is given.

8. The manufacturing method of the chassis-mounted welding sleeve according to claim 6, characterized in that, When the cold heading pressure of the six-step die is increased upward, the optical inspection further includes: Placing the formed workpiece on a rotatable workbench, irradiating the formed workpiece along the axis direction of the formed workpiece based on a line laser group, the line laser group includes at least five line laser emitters, and the line laser irradiation direction has an inclination angle with the vertical cross-section of the formed workpiece, collecting the surface profile of the formed workpiece rotating one week based on a CCD camera, and judging whether the formed workpiece is qualified according to the laser line length in the surface profile.

9. The manufacturing method of the chassis-mounted welding sleeve according to claim 8, characterized in that, When judging whether the formed workpiece is qualified according to the laser line length in the surface profile, it includes: When the similarity between the laser line lengths at each structure of the formed workpiece and the standard laser line length is greater than or equal to the similarity threshold, it is determined that the formed workpiece is qualified, and the formed workpiece is used as the workpiece to be finish-machined; When there is a similarity between a laser line length and the standard laser line length that is less than the similarity threshold, it is determined that the formed workpiece is unqualified, and an abnormal warning for workpiece processing is given.

10. A chassis-mounted welding sleeve prepared by the manufacturing method of the chassis-mounted welding sleeve according to any one of claims 1-9, characterized in that, It includes: Welding joints, including a straight cylinder welding joint and a flange welding joint; the flange welding joint adopts a flange structure, there are welding grooves and welding exhaust grooves at the flange, and a straight cylinder structure is arranged under the flange head for interference fit with the lower welding plate; dimensional tolerances are set for the straight cylinder welding joint, and after interference fit with the upper welding plate, welding reinforcement is carried out; The transition region between the straight cylinder welding joint and the flange welding joint adopts a cold forming integral forming structure; It also includes counterbore structures, which are arranged at the upper and lower ends; It also includes an internal thread structure.

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