Chassis mounting welding sleeve and manufacturing method thereof

Abstract

The present invention relates to the field of cold heading forming technology, and discloses a chassis mounting welding sleeve and a manufacturing method thereof, the method comprising: subjecting a wire rod to spheroidizing annealing, primary drawing, secondary spheroidizing annealing, and secondary drawing to obtain a workpiece to be cold headed; straightening the wire rod through a first-order die, and using a punch to press the blank into the die forming hole to punch out a shaping pit; using a second-order die to deepen the inner hole, adjust the diameter and length, and add a head-shaped chamfering die core; using a third-order die to stretch the rear hole to form a flange pre-contour; using a fourth-order die to extend the existing inner hole to reach a 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 to form a workpiece to be finely machined; performing inner hole turning and barrel plating to obtain a chassis mounting welding sleeve. The present application avoids the problems of dimensional error superposition and process discontinuity in traditional processing, and ensures the consistency of product structure.

Description

Technical Field

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

[0002] With the rapid development of the new energy vehicle industry, vehicle chassis have placed higher demands on the strength, precision, and assembly efficiency of battery pack mounting structures. In electric vehicle chassis design, the mounting welding sleeve is a key component connecting the load-bearing structure to the chassis. Its structural stability and processing technology are directly related to the safety performance and manufacturing cost of the entire vehicle.

[0003] In existing technology, welding sleeves are commonly manufactured using traditional bar turning or single-step stamping. These methods suffer from low material utilization, poor forming efficiency, and insufficient product consistency. This is particularly true for complex geometries (such as welding grooves and venting slots) and precision internal bores. Multiple machining passes often lead to accumulated dimensional deviations, necessitating subsequent correction steps. Furthermore, traditional processes often lack the systematic tempering of raw materials required for high-strength cold heading, leading to quality issues such as cracking, springback, and dimensional instability during the cold forming process.

[0004] Therefore, it is necessary to design a chassis mounting 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 mounting welding sleeve and a manufacturing method thereof, aiming to solve the current problems of poor welding sleeve forming efficiency, poor product consistency and unguaranteed product quality.

[0006] In one aspect, the present invention provides a method for manufacturing a chassis mounting welding sleeve, comprising:

[0007] The coil wire is subjected to spheroidizing annealing and then primary drawing, and then subjected to secondary spheroidizing annealing and then secondary drawing to obtain a workpiece to be cold-forged;

[0008] The workpiece to be cold headed is placed in a multi-station cold heading forming machine for cold heading forming, the disc element is straightened by the first sequence die, and the blank is pressed into the die forming hole by a punch to punch out a shaping pit; the inner hole is drawn by the second sequence die, the diameter and length are adjusted, and a head-shaped chamfering die core is added; the rear hole is stretched by the third sequence die to form a flange pre-contour; the existing inner hole is extended by the fourth sequence die to reach the target depth; the straight cylinder, welding groove and exhaust groove are formed by the fifth sequence die; the center hole of the sleeve is punched through by the sixth sequence die to form a through hole, and the workpiece to be finely processed is formed;

[0009] Performing inner hole turning on the workpiece to be finished using a CNC lathe to obtain a finished workpiece;

[0010] The finished workpiece is subjected to roller plating to obtain a chassis mounting welding sleeve.

[0011] Furthermore, the cold heading forming includes:

[0012] The beam strength ratio of the first-order forming process is 14-16%; and / or,

[0013] The upset ratio of the two-stage forming process is 11-15%; and / or,

[0014] The upset ratio of the three-stage forming process is 6-8%; and / or,

[0015] The upset ratio of the four-sequence forming process is 7-10%; and / or,

[0016] The upsetting ratio of the five-sequence forming process is 2-5%.

[0017] Furthermore, when the six-sequence die is used to punch through the center hole of the sleeve to form a through hole and form a workpiece to be finely machined, the process includes:

[0018] Based on the pressure sensor group, pressure data of several locations of the six-sequence mold are collected to establish a pressure data group;

[0019] taking the pressure data in the same horizontal plane in the pressure data group as a data group to be processed and plotting the data group to be processed as a two-dimensional pressure graph;

[0020] In the two-dimensional pressure map, a center point is arbitrarily determined ( );

[0021] Determine the neighborhood range with the central point as the center and r as the neighborhood radius;

[0022] Calculating the neighborhood average pressure based on the pressure data of each coordinate point within the neighborhood;

[0023] When the difference between the pressure data of the center point and the average pressure of the neighborhood is greater than a pressure difference threshold, the coordinates of the center point are determined to be a defect coordinate point, and the pressure difference threshold is a positive integer not equal to zero.

[0024] Furthermore, the neighborhood average pressure is calculated by the following formula:

[0025]

[0026] in, represents the neighborhood average pressure, r represents the neighborhood radius, ( , ) represents the coordinates of the center point, Represents a two-dimensional pressure map The pressure data of the point.

[0027] Furthermore, when the six-sequence die is used to punch through the center hole of the sleeve to form a through hole and form a workpiece to be finely machined, the method further includes:

[0028] When the defective coordinate point does not exist in all the data groups to be processed, the workpiece formed after the six-sequence molding is used as the workpiece to be finely machined;

[0029] When the defective coordinate point exists in any of the data groups to be processed, the defective coordinate point is recorded. If the pressure data of the defective coordinate point is less than the mold pressure limit, the cold heading pressure of the six-sequence mold is increased; if the pressure data of the defective coordinate point is greater than or equal to the mold pressure limit, a cold heading pressure warning is issued.

[0030] Furthermore, when the cold heading pressure of the six-sequence die is increased, it also includes:

[0031] Perform optical inspection on the workpiece formed by the six-sequence mold, and the optical inspection includes:

[0032] The molded workpiece is placed on a rotatable workbench, and is illuminated by parallel light. A CCD camera is used to capture the light-blocking profile of the molded workpiece after one rotation. All the light-blocking profiles are analyzed, and whether the molded workpiece is qualified is determined based on the analysis results.

[0033] Furthermore, judging whether the formed workpiece is qualified according to the analysis result includes:

[0034] When the similarity between all the light-blocking profiles and the standard light-blocking profile is greater than or equal to a similarity threshold, the formed workpiece is determined to be qualified, and the formed workpiece is used as the workpiece to be finished;

[0035] When the similarity between the light-blocking profile and the standard light-blocking profile is less than a similarity threshold, the formed workpiece is determined to be unqualified, and an abnormal workpiece processing warning is issued.

[0036] Furthermore, when the cold heading pressure of the six-sequence die is increased, the optical inspection further includes:

[0037] The formed workpiece is placed on a rotatable worktable and irradiated along the axis of the formed workpiece by 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 section of the formed workpiece. The surface profile of the formed workpiece after one rotation is collected by a CCD camera, and whether the formed workpiece is qualified is judged based on the length of the laser line in the surface profile.

[0038] Furthermore, judging whether the formed workpiece is qualified according to the length of the laser line in the surface profile includes:

[0039] When the similarity between the laser line length at each structure of the formed workpiece and the standard laser line length is greater than or equal to a similarity threshold, the formed workpiece is determined to be qualified and the formed workpiece is used as the workpiece to be finished;

[0040] When the similarity between the laser line length and the standard laser line length is less than a similarity threshold, the formed workpiece is determined to be unqualified, and an abnormal workpiece processing warning is issued.

[0041] Compared with the existing technology, the beneficial effects of the present invention are as follows: by subjecting the coil wire to spheroidizing annealing and drawing treatments in sequence, the structural properties and dimensional accuracy of the raw materials are optimized, providing a stable foundation for subsequent cold heading processing and improving the plasticity and crack resistance during the forming process; subsequently, a multi-station cold heading forming machine is used to sequentially complete the integral forming of key structures such as shaping pit punching, inner hole drawing, flange preforming, deep hole extension, straight tube and welding groove exhaust groove forming, and through-hole punching, thereby avoiding the problems of dimensional error superposition and process discontinuity in traditional multi-pass machining processes and ensuring the consistency of product structure and functional integration; on this basis, the inner hole is finely processed by a CNC lathe to further improve assembly accuracy, and the finished product is given good corrosion resistance through roller plating. The integration of multiple technical paths such as material tempering, cold forming and precision post-processing improves the structural strength, welding quality and service life of the sleeve and reduces manufacturing costs.

[0042] On the other hand, the present application also provides a chassis mounting welding sleeve, which is prepared using the above-mentioned chassis mounting welding sleeve manufacturing method, comprising:

[0043] The welding part includes a straight-tube welding part and a flange welding part; the flange welding part adopts a flange structure, and a welding groove and a welding exhaust groove are provided on the flange. A straight-tube structure is provided under the flange head for interference fit with the lower welding plate; the straight-tube welding part is provided with a dimensional tolerance, and is welded and reinforced after interference fit with the upper welding plate;

[0044] The transition area between the straight tube welding point and the flange welding point adopts a cold-formed integrally formed structure;

[0045] It also includes a countersunk hole structure, which is arranged at the upper and lower ends;

[0046] Also includes internal thread structure.

[0047] It can be understood that the above-mentioned chassis mounting welding sleeve and its preparation method have the same beneficial effects and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0049] Figure 1 A flow chart of a method for preparing a chassis mounting welding sleeve provided in an embodiment of the present invention;

[0050] Figure 2 A schematic diagram of cold heading during the preparation of a chassis mounting welding sleeve provided in an embodiment of the present invention;

[0051] Figure 3 A schematic structural diagram of a chassis mounting welding sleeve provided in an embodiment of the present invention.

[0052] Among them, 100, chassis mounting welding sleeve; 110, straight tube welding point; 120, flange welding point; 121, welding groove; 122, welding exhaust groove; 130, countersunk hole; 140, internal thread. DETAILED DESCRIPTION

[0053] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying 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 to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, unless there is a conflict, the embodiments of the present disclosure 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 accompanying drawings and in conjunction with the embodiments.

[0054] In the traditional existing welding sleeve manufacturing process, the material undergoes simple annealing and a single drawing before directly entering the cold heading process, resulting in insufficient refinement of the grain structure. During the cold heading process, insufficient material plasticity causes local stress concentration, resulting in surface cracking or internal microcracks on the workpiece. During multi-station cold heading, the distribution of deformation between the molds lacks systematic control, resulting in insufficient stretching of the flange pre-contour or uneven wall thickness of the straight tube section, which requires subsequent turning correction, resulting in reduced material utilization and extended processing cycle. In addition, the formation of welding grooves and exhaust grooves requires multiple stamping passes, and the stamping boundary conditions and mold parameters are not properly matched, resulting in fluctuations in the geometric accuracy of the groove body, and gaps or misalignments are easily generated during welding assembly.

[0055] For example, in the mass production of welding sleeves for new energy vehicle chassis, the wire rods are directly cold-forged after ordinary annealing. 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 first-order straightening of cold forging, the residual stress of the wire rod is not fully released, resulting in the axis of the blank offset after straightening. In the subsequent inner hole drawing process, the alignment between the mold and the blank deteriorates, and the roundness of the inner hole is out of tolerance. During the fifth-order forming of the welding groove, the punch pressure and the mold 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 weld pool formation. After the sixth-order punching, the surface roughness of the inner hole exceeds the allowable range of the turning allowance due to the intensification of cold work hardening, and a polishing process needs to be added.

[0056] If these issues are not addressed, microscopic defects generated during the cold heading stage will be exposed during the subsequent turning process, resulting in a reduction in the sleeve's load-bearing cross-sectional area, an expansion of the stress concentration area under dynamic loads, and a reduction in fatigue life. Geometric deviations between the weld groove and the exhaust slot will weaken the weld joint, triggering crack initiation and propagation in the vehicle's vibration environment, and threatening the stability of the battery pack mounting structure. The increased material loss and energy consumption caused by multiple process corrections will increase the manufacturing cost per unit and limit the economic viability of large-scale mass production.

[0057] In the face of the above problems, this application first addresses the problem of cold heading cracking caused by insufficient plasticity and uneven grain structure of the disc wire, and improves the formability of the material by optimizing the annealing and drawing process. Traditional single annealing is difficult to eliminate carbon segregation and residual stress inside the wire. This application adopts secondary spheroidizing annealing combined with staged drawing, and performs secondary annealing after the initial drawing to refine the grains and balance the hardness and ductility of the material. In order to solve the problem of unreasonable deformation distribution in multi-station cold heading forming, the mold process is re-planned, and the flange pre-contour and welding groove are formed in sequence to avoid wrinkles caused by excessive deformation in a single sequence. At the same time, in order to solve the problem of insufficient inner hole forming accuracy, a six-pass progressive punching process is designed to reduce the subsequent turning allowance by combining extended hole depth with shaping pits.

[0058] In some embodiments of the present application, see Figure 1-2 As shown, a method for manufacturing a chassis mounting welding sleeve is proposed, comprising:

[0059] S100: performing spheroidizing annealing on the coil wire and then performing primary drawing, performing secondary spheroidizing annealing and then performing secondary drawing to obtain a workpiece to be cold-forged;

[0060] S200: The workpiece to be cold-forged is placed in a multi-station cold-forging machine for cold-forging. The disc is aligned through the first-order die, and a punch is used to press the blank into the die forming hole to punch out a shaping pit. The second-order die is used to deepen the inner hole, adjust the diameter and length, and add a head-shaped chamfering die core. The third-order die is used to stretch the rear hole to form a flange pre-contour. The fourth-order die is used to extend the existing inner hole to reach the target depth. The fifth-order die is used to form a straight cylinder, welding grooves, and exhaust grooves. The sixth-order die is used to punch through the center hole of the sleeve to form a through hole, and the workpiece to be finished is formed.

[0061] S300: performing inner hole turning on the workpiece to be finished using a CNC lathe to obtain the finished workpiece;

[0062] S400: Barrel plating is performed on the finished workpiece to obtain a chassis mounting welding sleeve.

[0063] Specifically, spheroidizing annealing of coil wire refers to heating to a critical temperature and then slowly cooling it to eliminate internal stress and improve the ductility of the material. This can be achieved by using a continuous annealing furnace with segmented temperature control under nitrogen protection to reduce the risk of breakage during subsequent drawing. Primary drawing and secondary drawing refer to plastic processing of the wire through a die to gradually reduce its diameter. This can be achieved by using a roller die drawing machine in combination with a lubricant to ensure the wire diameter accuracy and surface quality. A multi-station cold heading forming machine refers to forming equipment with continuous transfer stations and integrated multiple dies. This can be achieved by using a six-station rotary press in combination with a servo drive system. The amount of single deformation is reduced by sequential and step-by-step forming. Single-sequence die straightening of coil refers to correcting the straightness of the wire. This can be achieved by using a V-shaped straightening die and a reverse extrusion process to eliminate forming eccentricity caused by coil bending. Pressing the punch into the die forming hole to punch out the shaping pit refers to using the punch to form a positioning groove on the end face of the blank. Specifically, this can be achieved by using a tapered punch in combination with a high-hardness die cavity to provide a centering reference for subsequent workstations. The second-order die drawing the inner hole refers to forming the inner cavity of the sleeve by reverse extrusion. Specifically, this can be achieved by using a stepped punch and a progressively expanding die to control the uniformity of the hole wall thickness. The third-order die stretching hole to form the flange pre-contour refers to constructing the flange prototype through radial material flow. Specifically, this can be achieved by using a combined die core with an annular flow channel to reduce stress concentration at the root of the flange. The fourth-order die inner hole is extended to the target depth by increasing the length of the inner hole through axial extrusion. Specifically, this can be achieved by using an extended punch with a limiting structure to ensure the inner hole depth tolerance. The fifth-order die forming straight cylinders, welding grooves and exhaust grooves refers to the simultaneous processing of complex geometric features through multi-directional parting. Specifically, this can be achieved by using a split die cavity and a lateral slider structure to avoid multiple clamping errors. Punching the center hole with a six-sequence die to create a through-hole removes residual material from the bottom, creating a through-hole. This can be achieved using a pin-type punching die to ensure a burr-free opening. Internal turning on a CNC lathe involves precision machining using program-controlled tool paths. This can be achieved using carbide inserts and a minimal lubrication system to correct for dimensional deviations in the internal hole after cold heading. Barrel plating involves electrolytically depositing a metal coating on a drum. This can be achieved using a zinc-nickel alloy electroplating solution and a pulsed current process to enhance the corrosion resistance of the sleeve surface.

[0064] It is understandable that the integrated and efficient forming of the sleeve structure is achieved through a process chain combining spheroidizing annealing and sequential cold heading with CNC finishing. Multi-station cold heading is used to form the straight barrel, flange, groove, and venting slot in a step-by-step manner, reducing material loss and processing times. Drawing and annealing processes optimize the material grain structure to avoid cold heading cracking. CNC turning compensates for cold heading dimensional deviations, ensuring internal bore accuracy and the required interference fit for assembly.

[0065] The working process and principle of this application are as follows: first, the wire rod of the disc element is subjected to spheroidizing annealing treatment to eliminate the internal stress of the material and improve the grain structure. After annealing, the initial drawing is carried out to refine the grains and improve the material strength through plastic deformation. Then a secondary spheroidizing annealing is carried out to further optimize the material structure. After another drawing, a workpiece to be cold headed with good plasticity and strength is obtained. The workpiece to be cold headed is placed in a multi-station cold heading forming machine for cold heading forming. The first-order mold straightens the disc element and punches out the shaping pit, laying the foundation for subsequent forming. The second-order mold deepens the inner hole and adjusts the size, and at the same time adds the head-shaped chamfering die core. The third-order mold stretches the rear hole to form the flange pre-contour, preparing for the final flange structure. The fourth-order mold further extends the inner hole to the target depth. The fifth-order mold forms complex structures such as straight cylinders, welding grooves and exhaust grooves. The sixth-order mold opens the center hole of the sleeve to form the workpiece to be finished. The inner hole of the workpiece to be finished is turned by a CNC lathe to improve the inner hole accuracy and surface quality. Finally, the finished workpiece undergoes barrel plating to enhance surface properties and create the finished chassis mount welding sleeve. This multi-pass cold heading process, combined with precision turning and surface treatment, effectively controls deformation at each forming stage, improving product dimensional accuracy and surface quality while ensuring the formation of complex structures.

[0066] As a preferred embodiment, the solution of this application is specifically implemented as follows:

[0067] First, the coil wire is annealed in a spheroidizing annealing furnace at a temperature of 700-750°C for 2-3 hours. After annealing, the wire is initially drawn, with a draw ratio between 1.2 and 1.5.

[0068] Perform secondary spheroidizing annealing at a temperature of 680-720°C for 1.5-2 hours. After another drawing, the workpiece is obtained for cold heading, with the final drawing ratio controlled between 1.8-2.2.

[0069] The workpiece to be cold-forged is placed in a six-station cold forging machine for cold forging. The first-stage die is made of carbide, with the inner diameter slightly larger than the workpiece. With the punch pressure set at 80-100 MPa, the blank is pressed into the die's forming hole, creating a 1-2 mm deep dent.

[0070] The second-stage die is made of high-speed steel, and the internal depth of the drawn hole is 40-50% of the total length of the workpiece. The angle of the head chamfer is set at 30-45°. The third-stage die is stretched to form the flange pre-profile, and the flange outer diameter increases by 10-20% of the original diameter.

[0071] The fourth die continues to extend the inner hole to the target depth. The fifth die forms the straight section and creates welding grooves and venting slots with a width of 2-3mm and a depth of 1-1.5mm at the flange. The sixth die uses a carbide punch with a punching pressure of 120-150MPa to punch through the center hole of the sleeve to form a through hole.

[0072] The workpiece to be finished is internally turned using a CNC lathe. The turning feed is set at 0.1-0.2 mm / r and the cutting depth is 0.2-0.5 mm. Finally, the finished workpiece is plated in a barrel plating machine, with the coating thickness controlled at 5-10 μm.

[0073] It is understood that this application can effectively improve the forming accuracy and surface quality of the chassis mounting welding sleeve. The multi-pass cold heading process can control the deformation at each stage, reduce internal stress accumulation, and reduce the risk of cracking. Precision turning and surface treatment further optimize product performance. The dimensional accuracy, surface quality, and structural strength of the welding sleeve are improved to meet the strict requirements of the new energy vehicle chassis for the battery pack mounting structure. At the same time, this process can improve material utilization, reduce processing allowances, and reduce manufacturing costs.

[0074] In some of the above-mentioned solutions of the present application, during the multi-station cold heading process, the deformation amount of each process is improperly controlled, resulting in uneven stress distribution inside the material, which can easily cause workpiece cracking or dimensional deviation, affecting the sleeve forming quality.

[0075] The present application further proposes a method for manufacturing a chassis mounting welding sleeve, comprising the following steps: the strength 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%; and the upsetting ratio of the fifth-sequence forming process is 2-5%.

[0076] Among them, the beam ratio is defined as a quantitative parameter of the cross-sectional area reduction ratio during the straightening process of the disk element, and the upsetting ratio represents the percentage of axial compression deformation. The numerical range of the first-order beam ratio limits the degree of plastic deformation in the initial straightening stage to avoid microcracks on the material surface; the upsetting ratios of the second to fifth orders are configured in a gradient decreasing manner, and by gradually reducing the deformation rate in stages, the metal grains flow in an orderly manner during the cold upsetting process, reducing local stress concentration. For example, the second-order upsetting ratio is set to 11-15% to ensure that the material ductility matches the mold cavity during the inner hole drawing; the third and fourth orders correspond to the flange pre-contour forming and the inner hole extension, respectively, and their upsetting ratios are reduced to 6-10% to avoid excessive work hardening; the fifth-order upsetting ratio is further controlled at 2-5% to maintain structural accuracy when forming straight tubes and welding grooves.

[0077] Specifically, during the first-order straightening stage, when the beam ratio is lower than 14%, the wire rod is not fully straightened, resulting in subsequent cold heading positioning deviation; if it exceeds 16%, scratches are easily generated on the wire rod surface or internal grains are broken. By limiting the beam ratio to 14-16%, the bending stress of the wire rod can be eliminated while retaining the toughness of the material. During the second-order deep drawing of the inner hole, 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 are synchronized to the design value. At the same time, the embedding angle of the head chamfer die core is adapted to the upsetting deformation to avoid wrinkles on the hole wall. During the third-order flange pre-contouring stage, an upsetting ratio of 6-8% allows the material to flow in layers within the die, forming a uniform flange thickness gradient; the fourth-order inner hole extension adopts an upsetting ratio of 7-10%. By adjusting the punch pressure and the die gap, the hole depth is increased while maintaining the inner wall smoothness. During the five-sequence straight sleeve forming process, a 2-5% upset ratio, combined with a multi-stage ejection mechanism, ensures that the geometric accuracy of the welding groove and exhaust slot is controlled within ±0.02mm. The cold heading machine servo system adjusts the punching force and stroke speed of each process parameter in real time, achieving dynamic matching of deformation, ultimately increasing the material utilization rate of the sleeve forming process to over 92%, and eliminating cracking defects.

[0078] As a preferred embodiment, the solution of this application is specifically implemented as follows:

[0079] During cold upsetting, the strength beam ratio of the one-sequence forming process is 15%; the upsetting ratio of the two-sequence forming process is 13%; the upsetting ratio of the three-sequence forming process is 7%; the upsetting ratio of the four-sequence forming process is 8%; and the upsetting ratio of the five-sequence forming process is 3%.

[0080] Through the above-mentioned technical solution, this application achieves the optimal configuration of process parameters for each sequence in the cold upsetting process. This improves production efficiency and reduces material waste while ensuring forming quality. Furthermore, by rationally controlling the beam-to-burst ratio and upsetting ratio of each forming process sequence, quality issues such as cracking and springback during the forming process are avoided, improving the dimensional accuracy and surface quality of the product.

[0081] In some of the above-mentioned solutions of the present application, when the central through hole of the sleeve is formed by a cold heading process, uneven pressure distribution inside the mold may cause local defects in the workpiece, such as material accumulation or cracks, affecting the subsequent finishing quality and reliability of the finished product.

[0082] The present application further proposes to collect pressure data at several locations of a six-sequence mold based on a pressure sensor group to establish a pressure data group; to treat the pressure data at the same horizontal plane in the pressure data group as a data group to be processed and to plot the data group to be processed as a two-dimensional pressure map; to arbitrarily determine a center point in the two-dimensional pressure map; to determine a neighborhood range with the center point as the center of a circle and r as the neighborhood radius; to calculate the neighborhood average pressure based on 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 a pressure difference threshold, the coordinates of the center point are determined to be a defective coordinate point, and the pressure difference threshold is a positive integer that is not zero.

[0083] Among them, the pressure sensor group is embedded in multiple key stress-bearing areas of the six-sequence mold, such as the mold ejector, the side wall of the forming hole, and the flange pre-contour contact surface. The construction of the two-dimensional pressure map is based on the superposition mapping of the pressure data of the same axial section. The coordinates of the center point can be determined by random selection or based on the geometric symmetry center of the mold. The value of the neighborhood radius r is proportional to the mold size, for example, 5%-8% of the mold diameter. The setting of the pressure difference threshold is based on the dynamic matching of the material yield strength and the mold load limit, for example, 0.5%-1.2% of the material elastic modulus is used as the benchmark value.

[0084] Specifically, when the six-sequence mold performs sleeve center hole forming, the pressure sensor collects dynamic pressure data at different positions of the mold in real time. The pressure data of the same horizontal plane forms a two-dimensional pressure distribution diagram after coordinate conversion. By selecting the center point and calculating the average pressure of its neighborhood, the local pressure abnormality area can be identified. When the difference between the center point pressure and the neighborhood average pressure exceeds the threshold, it indicates that there is stress concentration or material flow defect in the area. The expansion of defects can be avoided by adjusting the cold heading pressure or triggering the early warning mechanism. For example, when the pressure at the defect point is lower than the mold 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 mold is prompted to be repaired. This process realizes real-time monitoring and active regulation of molding defects, effectively reducing the defective rate. As a preferred embodiment, the solution of the present application is specifically implemented as follows:

[0085] The pressure sensor group collects pressure data from several locations on the six-sequence mold to create a pressure data set. The pressure sensor group includes multiple pressure sensors evenly distributed at key locations on the six-sequence mold. Each pressure sensor collects pressure data at its location in real time and transmits the data to the central processing unit. The central processing unit receives data from all pressure sensors and integrates the data into a single pressure data set.

[0086] The pressure data on the same horizontal plane within the pressure data set are considered as a data set to be processed, and this data set is plotted as a two-dimensional pressure map. Specifically, the pressure data on the same horizontal plane of the six-sequence mold are selected and considered as a data set to be processed. Using computer graphics software, the position of the pressure sensor on the horizontal plane is represented by x and y coordinates, and the pressure level is represented by color depth or height, to generate a two-dimensional pressure map.

[0087] Arbitrarily determine a center point in the 2D pressure map. For example, you can select the center of the pressure map, or an area with high pressure values.

[0088] The neighborhood range is determined with the center point as the circle center and r as the neighborhood radius. The neighborhood radius r can be adjusted according to the mold size and pressure distribution characteristics to ensure that the neighborhood range can represent the local pressure distribution.

[0089] The neighborhood average pressure is calculated based on the pressure data of each coordinate point within the neighborhood. Specifically, the values of all pressure data points within the neighborhood are extracted, and the arithmetic mean of these data points is calculated to obtain the neighborhood average pressure.

[0090] When the difference between the pressure data of the center point and the average pressure of the neighborhood exceeds the pressure difference threshold, the coordinates of the center point are determined to be a defect coordinate point. The pressure difference threshold is a non-zero positive integer. For example, the pressure difference threshold can be set to 5MPa. If the difference between the pressure of the center point and the average pressure of the neighborhood exceeds 5MPa, the center point is determined to be a defect coordinate point.

[0091] Through the above technical solution, the present application can effectively detect pressure anomalies during the six-sequence mold forming process. This improves the molding quality and consistency of the chassis mounting welding sleeve. Furthermore, the method can promptly detect the problem of uneven mold pressure distribution and avoid workpiece defects caused by excessive or insufficient local pressure. Specifically, by analyzing the two-dimensional pressure map and calculating the average pressure of the neighborhood, the pressure anomaly points can be accurately identified, thereby guiding the adjustment of the cold heading pressure or issuing an early warning. The quality control method based on data analysis improves the manufacturing accuracy and reliability of the chassis mounting welding sleeve.

[0092] In some of the aforementioned approaches to defect detection using pressure data sets, it is necessary to calculate the average pressure of the neighborhood to determine whether a defect exists at the center point. However, because the pressure distribution of each point on a two-dimensional pressure map may exhibit nonlinear variations, a simple arithmetic average method cannot accurately reflect the true pressure distribution within the neighborhood, leading to misjudgment or omission of defect coordinate points.

[0093] This application further proposes that the neighborhood average pressure is calculated by the following formula:

[0094]

[0095] in, represents the neighborhood average pressure, r represents the neighborhood radius, ( , ) represents the coordinates of the center point, Represents a two-dimensional pressure diagram The pressure data of the point.

[0096] The neighborhood range is defined by a circular area with radius r, centered around the center point. The area encompasses all discrete pressure points within the area. Pressure data is distributed on the pressure map as two-dimensional coordinates, with each coordinate point corresponding to a real-time pressure value collected by the pressure sensor array. During the calculation, the values of all pressure points within the neighborhood are integrated and summed, then divided by the neighborhood area to obtain the average pressure per unit area. The integration range spans from to on the x-axis and to on the y-axis, ensuring that all pressure points within the neighborhood are included in the calculation.

[0097] Specifically, the pressure distribution in the neighborhood is processed continuously through integration operations to eliminate the calculation deviation caused by the spacing between 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 weighted sum of each pressure value in the area is taken to accurately reflect the pressure distribution trend. During the calculation, if there is a pressure mutation point in the neighborhood, the integration result will significantly reflect the impact of the mutation on the average pressure. Furthermore, by standardizing the calculation process, errors caused by human experience intervention are avoided, and the consistency of the calculation results when different batches or different operators are executed is ensured. As a result, the judgment standard of the defect coordinate point has higher objectivity and repeatability, which effectively improves the accuracy of quality inspection in the six-sequence mold forming process.

[0098] As a preferred embodiment, the solution of this application is specifically implemented as follows:

[0099] To calculate the neighborhood average pressure, first determine a neighborhood radius, r. For example, you can choose 5mm as the neighborhood radius. Then, draw a circle with the selected center point (x0, y0) as the center and r as the radius. The pressure values of all pressure data points within the circle are accumulated and summed. Finally, divide the sum by the total number of pressure data points in the neighborhood to obtain the neighborhood average pressure value for that center point.

[0100] Furthermore, to improve calculation accuracy, interpolation methods can be used to process the pressure data within the neighborhood. For example, bilinear interpolation can be used to calculate the pressure value at any location within the circle based on nearby known pressure data points. This can more accurately reflect the pressure distribution within the neighborhood.

[0101] Therefore, by calculating the average pressure of the neighborhood, the random fluctuations of individual pressure data points can be effectively eliminated, resulting in a more stable and reliable pressure assessment result. This provides an important basis for the subsequent determination of the defect coordinates.

[0102] Through the above technical solution, this application can accurately calculate the average pressure of the neighborhood around any center point in a two-dimensional pressure map. By comparing the center point pressure with the neighborhood average pressure, it is possible to effectively identify pressure anomalies, thereby promptly discovering potential defects in the cold heading process. This method not only improves the accuracy of defect detection but also enables real-time monitoring of the cold heading process, helping to improve product quality and production efficiency.

[0103] In some of the aforementioned solutions of this application, pressure data is used to determine whether the cold heading process meets the requirements, and the cold heading pressure is adjusted based on the determination result. However, the actual forming state of the workpiece after the cold heading pressure adjustment still needs to be verified. If the adjusted forming effect is not re-tested, local deformation defects may remain undetected, resulting in the accumulation of processing errors in subsequent steps.

[0104] This application further proposes a step of optically inspecting the formed workpiece after increasing the cold heading pressure. This optical inspection step includes placing the formed workpiece on a rotatable worktable, illuminating the formed workpiece with parallel light, using a CCD camera to capture the light-blocking profile of the formed workpiece during one rotation, analyzing all the light-blocking profiles, and determining whether the formed workpiece is qualified based on the analysis results.

[0105] The rotatable worktable is driven by a servo motor, and its rotation angle accuracy is controlled within the range of ±0.1 degrees. The wavelength range of the parallel light source 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 contour analysis extracts edge features through a grayscale image processing algorithm and matches them point by point with the standard contour. The similarity threshold is set to 98%. When the similarity of the light blocking contour at any angle is lower than the threshold, an abnormal workpiece processing warning is triggered.

[0106] Specifically, the formed workpiece rotates at a constant angular velocity driven by a rotatable worktable, and parallel light is projected along the axis of the workpiece to form an illumination plane perpendicular to the surface of the workpiece. The CCD camera captures the projected contour of the workpiece during rotation at a fixed frequency, generating a sequence of light-blocking images of continuous frames. The image processing system performs edge sharpening and noise elimination on each frame of the image to extract the contour line coordinate data. The actual contour and the standard contour are converted to the frequency domain through Fourier transform, and the similarity of the energy distribution of the two in the low-frequency band 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 is an abnormal contour below the threshold, the pressure adjustment strategy is judged to be invalid and the processing process needs to be terminated. This detection method can complete full-circle detection of the workpiece within 0.5 seconds through optical non-contact measurement, avoiding secondary damage caused by mechanical contact.

[0107] As a preferred embodiment, the solution of this application is specifically implemented as follows:

[0108] When there are no defective coordinate points in all the data groups to be processed, the workpiece after six-sequence forming is regarded as the workpiece to be finished.

[0109] If a defective coordinate point exists in any data set to be processed, the defective coordinate point is recorded. If the pressure data at the defective coordinate point is less than the mold pressure limit, the cold heading pressure of the six-sequence mold is increased. If the pressure data at the defective coordinate point is greater than or equal to the mold pressure limit, a cold heading pressure warning is issued.

[0110] Specifically, in the process of punching the center hole of the sleeve to form a through hole in the six-sequence mold, pressure data from multiple positions of the six-sequence mold are first collected to establish a pressure data group. The pressure data of the same horizontal plane are used as the data group to be processed and plotted as a two-dimensional pressure map. A center point is determined in the two-dimensional pressure map, and the neighborhood range is determined with the center point as the center of the circle and the preset neighborhood radius. The average pressure of each coordinate point in the neighborhood range is calculated. When the difference between the center point pressure data and the neighborhood average pressure is greater than the preset pressure difference threshold, the center point coordinate is determined to be a defective coordinate point.

[0111] Furthermore, all data sets to be processed are analyzed. If no defective coordinate points exist, the workpiece formed after the six-sequence forming process is directly used as the workpiece for finishing. If a defective coordinate point exists, it is recorded. Based on the comparison of the pressure data at the defective coordinate point with the mold pressure limit, a decision is made as to whether to increase the cold heading pressure or issue a pressure warning.

[0112] Through the above technical solution, this application can monitor the pressure distribution during the six-sequence mold forming process in real time, and promptly detect and locate molding defects. Based on the pressure data at the defect location, the cold heading pressure can be adaptively adjusted or an early warning can be issued to avoid the production of unqualified workpieces. This method improves the stability of the forming process and the quality of the workpiece, reduces rework and scrap in subsequent processing links, and thus improves production efficiency and material utilization.

[0113] In some of the above-mentioned solutions of this application, there is a lack of effective means to verify the quality of the formed workpiece after the cold heading pressure is adjusted. The change in pressure parameters may cause abnormal internal structure of the workpiece or surface defects to not be discovered in time, affecting the subsequent assembly accuracy and welding strength.

[0114] The present application further proposes to perform optical inspection on the workpiece after six-sequence mold forming, including placing the molded workpiece on a rotatable workbench, irradiating the molded workpiece with parallel light, using a CCD camera to collect the light-blocking contour of the molded workpiece after one rotation, analyzing all the light-blocking contours, and judging whether the molded workpiece is qualified based on the analysis results.

[0115] The rotatable worktable is driven by a servo motor, enabling 360-degree precise indexing. A parallel light generator is located on the side of the worktable, with the optical axis perpendicular to the workpiece axis. A CCD camera equipped with a high-resolution industrial lens captures contour images at a rate of 50 frames per second. Light-blocking contour analysis uses an image grayscale comparison algorithm to perform point cloud matching between the real-time collected contour edge coordinates and the standard contour coordinates.

[0116] Specifically, the formed workpiece is fixed to the workbench fixture and then starts to rotate, with image acquisition triggered every 1 degree of rotation. When parallel light penetrates the workpiece, the CCD camera captures the projected contour of the workpiece shape and generates a set of light-blocking contour data for continuous sections. After all contour data are filtered and denoised, the similarity is evaluated by calculating the root mean square error 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 the area. If the error values of three consecutive sections exceed the threshold, an early warning signal is triggered and the production line is suspended. The detection process is completed within 20 seconds, covering the geometric features of the entire circumference of the workpiece, and effectively identifying ovality deviations or axial bending defects caused by cold heading pressure adjustment.

[0117] As a preferred embodiment, the solution of this application is specifically implemented as follows:

[0118] After increasing the cold heading pressure of the six-sequence die, the workpiece formed by the six-sequence die is also optically inspected. The optical inspection includes the following steps:

[0119] First, the formed workpiece is placed on a rotatable worktable. The worktable is driven by a precision motor and can rotate 360 degrees with an accuracy of 0.1 degrees.

[0120] Next, the workpiece is illuminated with a parallel light source, which uses an LED array with adjustable light intensity and a wavelength range of 400-700nm.

[0121] Then, a CCD camera with a resolution of 1920x1080 pixels and a sampling frequency of 60Hz is used to capture the light-blocking profile of the molded workpiece during one rotation.

[0122] Finally, all light-blocking contours are analyzed, and the quality of the formed workpiece is determined based on the analysis results. The analysis process uses image processing algorithms, including edge detection, contour extraction, and shape matching.

[0123] Through the above technical solution, the present application realizes all-round optical inspection of the workpiece after six-sequence mold forming. In this way, defects in the molding process can be discovered in a timely manner, and the accuracy and efficiency of product quality control are improved. Furthermore, this method does not require human intervention and can realize automated detection, which reduces human errors and improves the consistency and reliability of detection. Specifically, by collecting the light-blocking contour of the workpiece after one rotation, the geometric features of the workpiece surface can be fully captured, including complex structures such as welding grooves and exhaust grooves, thereby achieving an accurate assessment of the overall shape of the workpiece.

[0124] In some of the above-mentioned solutions of the present application, the optical inspection of the formed workpiece after the cold heading pressure is adjusted only uses a single inspection method to judge the acceptability of the workpiece, which may result in local defects or dimensional deviations not being effectively identified, thereby affecting the sleeve assembly accuracy and structural strength.

[0125] The present application further proposes that when the similarity between all light-blocking contours and the standard light-blocking contour is greater than or equal to a similarity threshold, the formed workpiece is judged to be qualified and the formed workpiece is used as the workpiece to be fine-machined; when the similarity between a light-blocking contour and the standard light-blocking contour is less than the similarity threshold, the formed workpiece is judged to be unqualified and an abnormal workpiece processing warning is issued.

[0126] Among them, the light-blocking contour is obtained by irradiating the rotating workpiece with parallel light and captured by a CCD camera, covering the surface morphology of the entire circumference of the workpiece; the similarity threshold is set to no less than 95%, and the image matching algorithm is used to calculate the overlap between the actual light-blocking contour and the standard contour; after the early warning signal is triggered, the production line is automatically paused and the position of the abnormal workpiece is marked.

[0127] Specifically, after the formed workpiece is placed on a rotatable worktable, a parallel light source is projected along the axial direction to form uniform lighting, and a CCD camera captures the projected contour of the workpiece edge during rotation at a fixed frame rate. After pre-processing, the light-blocking contour data is compared point by point with the pre-stored standard contour, and the similarity is comprehensively evaluated by calculating the pixel overlap and curvature matching. When the similarity of any cross-section is lower than the threshold, it is determined that there is structural deformation or processing error. The system immediately issues an early warning and records the abnormal position to facilitate rapid positioning of the defective area. This judgment mechanism avoids subjective errors in manual visual inspection by quantifying the degree of contour matching, ensuring that the internal and external dimensions of the sleeve strictly meet the design tolerance requirements.

[0128] As a preferred embodiment, the solution of this application is specifically implemented as follows:

[0129] When the similarity between all light-blocking profiles and the standard light-blocking profile is greater than or equal to a similarity threshold, the formed workpiece is determined to be qualified and is used as a workpiece to be finished.

[0130] When the similarity between the existing light-blocking profile and the standard light-blocking profile is less than a similarity threshold, the formed workpiece is judged to be unqualified and an abnormal workpiece processing warning is issued.

[0131] Specifically, the similarity threshold can be set to 0.95. First, place the molded workpiece on a rotatable workbench and use a parallel light source to illuminate the molded workpiece. Then, use a CCD camera to collect the light-blocking contour image of the molded workpiece after one rotation. Next, compare each collected light-blocking contour image with the pre-stored standard light-blocking contour image to calculate the similarity. If the similarity between all collected light-blocking contour images and the standard image is greater than or equal to 0.95, the molded workpiece is judged to be qualified and can enter the next finishing process. On the contrary, if there is any light-blocking contour image with a similarity of less than 0.95 with the standard image, the molded workpiece is judged to be unqualified, and the system will issue a workpiece processing abnormality warning signal to prompt the operator to check and handle it.

[0132] Through the above technical solution, the present application can quickly and accurately determine whether the formed workpiece is qualified. This allows unqualified workpieces to be discovered and eliminated in a timely manner, preventing them from entering subsequent processing links, thereby improving the efficiency and accuracy of product quality control. At the same time, by setting a similarity threshold, the judgment criteria can be flexibly adjusted to meet the quality requirements of different products. In addition, the use of optical detection methods eliminates the need to contact the workpiece surface, which can reduce damage to the workpiece and ensure that the detection process does not affect the quality of the workpiece.

[0133] In some of the above-mentioned solutions of the present application, the detection method based on parallel light irradiation of the molded workpiece to perform light blocking contour analysis can easily lead to unclear contour boundaries in strong light environments, thereby affecting the accuracy of the final workpiece quality judgment.

[0134] The present application further proposes placing the formed workpiece on a rotatable worktable, irradiating the formed workpiece along the axis of the formed workpiece based on a line laser group, the line laser group including 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 after one rotation based on a CCD camera, and judging whether the formed workpiece is qualified based on the length of the laser line in the surface profile.

[0135] The line laser array consists of multiple emitters arranged at varying inclination angles, covering all axial regions of the workpiece. Multi-beam projection forms a detection network. Five line laser emitters are arranged in the same plane, not directly facing the workpiece. The inclination angles are controlled within a range of 5° to 15°, resulting in a bright vertical line on the workpiece surface. The light rays not on the workpiece surface have an inflection point with those on the workpiece surface, facilitating the identification of light boundary. A CCD camera synchronously captures the deformation data of the laser line during rotation at a high frame rate to construct surface segment data.

[0136] Specifically, after the formed workpiece is fixed on the rotating worktable, each line laser emitter projects a beam toward 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 weld, flange weld, and transition area. The CCD camera records the laser line length data at each angle and identifies the workpiece surface dimension data by comparing it with the baseline laser line length distribution curve of the standard workpiece. When it is detected that the laser line length at any structure deviates from the standard curve by more than ±0.05mm, an abnormal workpiece processing warning is automatically triggered, and the difference data of the defect position is output synchronously. This effectively eliminates the risk of misjudgment of a single detection method and improves the full-process quality control capability of high-precision cold heading workpieces.

[0137] As a preferred embodiment, the solution of this application is specifically implemented as follows: After adjusting the cold heading pressure, the formed workpiece is placed on a rotatable worktable. Five line laser emitters are used to project laser beams along the workpiece axis, with each line laser at a 5-degree inclination angle to the vertical cross-section of the workpiece. A CCD camera synchronously captures the laser lines reflected from the surface of the workpiece during its 360-degree rotation. By comparing the laser line lengths of various structural components with preset standard values, if the laser line length deviation exceeds ±0.1 mm, a processing anomaly warning is triggered, and unqualified workpieces are automatically sorted to a rework station.

[0138] The above technical solution solves the problem of difficulty in fully detecting the workpiece surface morphology by only using light-blocking contour analysis after adjusting the cold heading pressure in a strong light environment. This results in local depressions or protrusions on the workpiece not being effectively identified, affecting the accuracy of subsequent welding and assembly. This application effectively solves the problem of surface feature detection. By combining tilted laser projection with rotational scanning, deformation monitoring is achieved, avoiding the misjudgment of structural obscuration caused by traditional detection, ensuring that the workpiece deformation after the cold heading pressure adjustment is controlled within the welding and assembly tolerance range, and reducing the risk of false welds and stress concentration in subsequent welding processes.

[0139] In the above embodiment, by subjecting the disc wire to spheroidizing annealing and drawing treatments in sequence, the structural properties and dimensional accuracy of the raw materials are optimized, providing a stable foundation for subsequent cold heading processing and improving the plasticity and crack resistance during the forming process; then, a multi-station cold heading forming machine is used to sequentially complete the integral forming of key structures such as shaping pit punching, inner hole drawing, flange preforming, deep hole extension, straight tube and welding groove exhaust groove forming, and through-hole punching, thereby avoiding the problems of dimensional error superposition and process discontinuity in traditional multi-process machining and ensuring the consistency of product structure and functional integration; on this basis, the inner hole is finely processed by a CNC lathe to further improve the assembly accuracy, and the finished product is given good corrosion resistance through roller plating. The integration of multiple technical paths such as material tempering, cold forming and precision post-processing improves the structural strength, welding quality and service life of the sleeve and reduces manufacturing costs.

[0140] In another preferred embodiment based on the above embodiment, refer to Figure 3 As shown, this embodiment provides a chassis mounting welding sleeve, which is prepared using the above-mentioned chassis mounting welding sleeve manufacturing method, including:

[0141] The welding part includes a straight-tube welding part 110 and a flange welding part 120; the flange welding part 120 adopts a flange structure, and is provided with a welding groove 121 and a welding exhaust groove 122. A straight-tube structure is provided under the flange head for interference fit with the lower welding plate; the straight-tube welding part 110 is provided with a dimensional tolerance, and is then welded and reinforced after interference fit with the upper welding plate;

[0142] The transition area between the straight tube welding point 110 and the flange welding point 120 adopts a cold-formed integrally formed structure;

[0143] It also includes a countersunk hole 130 structure, which is provided at the upper and lower ends;

[0144] An internal thread 140 structure is also included.

[0145] Specifically, the welding groove 121 of the flange weld 120 is used to accommodate the weld metal, and the welding exhaust groove 122 can exhaust the gas generated during the welding process to avoid porosity defects. The interference fit design of the straight tube weld 110 and the flange weld 120 is controlled by dimensional tolerance to ensure that welding reinforcement can be performed after assembly without secondary trimming. The cold-formed one-piece molding structure directly forms a transition area through a multi-station cold heading process, reducing the residual stress caused by split welding. The countersunk hole 130 structure facilitates the embedding of the bolt head; the internal thread 140 structure is formed by fine processing on a CNC lathe, and the thread accuracy meets the high torque assembly requirements.

[0146] Specifically, the flange weld 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 tube weld 110 is welded and reinforced after interference fit with the upper welding plate. Its dimensional tolerance is controlled within ±0.02 mm to ensure assembly accuracy. The transition area is integrally formed by a cold heading process to eliminate the weakening of material strength caused by traditional welding or machining. The depth of the countersunk hole 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 tooth profile is processed by CNC turning, and the pitch error is less than 0.01 mm to ensure the stability of the engagement with the bolt.

[0147] As a preferred embodiment, the solution of this application is implemented as follows: The welding sleeve comprises a straight-tube weld 110 and a flange weld 120. The flange weld 120 features an annular flange with a 1.2 mm deep U-shaped groove at its outer edge. Three trapezoidal exhaust channels, each 0.5 mm wide, are spaced at intervals at the bottom of the groove. A cylindrical straight tube with an axial length of 12 mm extends below the flange. The outer diameter of this straight tube forms a 0.05 mm interference fit with the mounting hole of the lower chassis weld plate. The top of the straight-tube weld 110 features a 1:50 taper, which is clearance-fitted with the upper weld plate and reinforced by laser welding. The connection between the straight-tube and flange features a continuously tapered wall thickness, with a smooth transition from 3 mm to 5 mm achieved through cold heading. Stepped counterbores with a depth of 8 mm are machined into the inner wall of each end of the sleeve. The bottom of the counterbores features an M12×1.75 internal thread structure, achieving an effective thread engagement length of 6 mm.

[0148] Through the above technical solutions, this application achieves optimized stress distribution and assembly precision control of welded joints. The groove structure at the flange welding site effectively accommodates the weld metal, the exhaust channel prevents the generation of welding bubbles, and the interference fit design of the straight barrel eliminates assembly gaps. The cold-formed integrated structure eliminates the stress concentration problem of traditional welded joints. The combined design of countersunk holes and internal threads meets the assembly requirements of bolts of different specifications and reduces the use of auxiliary positioning tooling. This structural solution enables the welding sleeve to evenly transfer stress to the flange through the gradient wall thickness area when it is subjected to axial load, significantly improving the fatigue resistance of the connection node.

[0149] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0150] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0151] These computer program instructions may 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, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0152] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1A step that specifies a function in one or more boxes.

[0153] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A method for manufacturing a chassis mounting welding sleeve, characterized in that: include: The coil wire is subjected to spheroidizing annealing and then primary drawing, and then subjected to secondary spheroidizing annealing and then secondary drawing to obtain a workpiece to be cold-forged; The workpiece to be cold headed is placed in a multi-station cold heading forming machine for cold heading forming, the disc element is straightened by the first sequence die, and the blank is pressed into the die forming hole by a punch to punch out a shaping pit; the inner hole is drawn by the second sequence die, the diameter and length are adjusted, and a head-shaped chamfering die core is added; the rear hole is stretched by the third sequence die to form a flange pre-contour; the existing inner hole is extended by the fourth sequence die to reach the target depth; the straight cylinder, welding groove and exhaust groove are formed by the fifth sequence die; the center hole of the sleeve is punched through by the sixth sequence die to form a through hole, and the workpiece to be finely processed is formed; Performing inner hole turning on the workpiece to be finished using a CNC lathe to obtain a finished workpiece; Performing barrel plating on the finished workpiece to obtain a chassis mounting welding sleeve; When using a six-sequence die to punch through the center hole of the sleeve to form a through hole and form a workpiece to be finished, it includes: Based on the pressure sensor group, pressure data of several locations of the six-sequence mold are collected to establish a pressure data group; taking the pressure data in the same horizontal plane in the pressure data group as a data group to be processed and plotting the data group to be processed as a two-dimensional pressure graph; In the two-dimensional pressure map, a center point is arbitrarily determined ( ); Determine the neighborhood range with the central point as the center and r as the neighborhood radius; Calculating the neighborhood average pressure based on the pressure data of each coordinate point within the neighborhood; When the difference between the pressure data of the center point and the average pressure of the neighborhood is greater than the pressure difference threshold, the coordinates of the center point are determined to be defective coordinate points, and the pressure difference threshold is a positive integer that is not zero; The neighborhood average pressure is calculated by the following formula: ； in, represents the neighborhood average pressure, r represents the neighborhood radius, ( , ) represents the coordinates of the center point, Represents a two-dimensional pressure map Pressure data of the point; When using a six-sequence die to punch through the center hole of the sleeve to form a through hole and form a workpiece to be finished, it also includes: When the defective coordinate point does not exist in all the data groups to be processed, the workpiece formed after the six-sequence molding is used as the workpiece to be finely machined; When the defective coordinate point exists in any of the data groups to be processed, the defective coordinate point is recorded. If the pressure data of the defective coordinate point is less than the mold pressure limit, the cold heading pressure of the six-sequence mold is increased; if the pressure data of the defective coordinate point is greater than or equal to the mold pressure limit, a cold heading pressure warning is issued.

2. The method for manufacturing a chassis mounting welding sleeve according to claim 1, characterized in that: The cold heading forming process comprises: The beam strength ratio of the first-order forming process is 14-16%; and / or, The upset ratio of the two-stage forming process is 11-15%; and / or, The upset ratio of the three-stage forming process is 6-8%; and / or, The upset ratio of the four-sequence forming process is 7-10%; and / or, The upsetting ratio of the five-sequence forming process is 2-5%.

3. The method for manufacturing a chassis mounting welding sleeve according to claim 1, characterized in that: When the cold heading pressure of the six-sequence die is increased, it also includes: Perform optical inspection on the workpiece formed by the six-sequence mold, and the optical inspection includes: The molded workpiece is placed on a rotatable workbench, and is illuminated by parallel light. A CCD camera is used to capture the light-blocking profile of the molded workpiece after one rotation. All the light-blocking profiles are analyzed, and whether the molded workpiece is qualified is determined based on the analysis results.

4. The method for manufacturing a chassis mounting welding sleeve according to claim 3, 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 a similarity threshold, the formed workpiece is determined to be qualified, and the formed workpiece is used as the workpiece to be finished; When the similarity between the light-blocking profile and the standard light-blocking profile is less than a similarity threshold, the formed workpiece is determined to be unqualified, and an abnormal workpiece processing warning is issued.

5. The method for manufacturing a chassis mounting welding sleeve according to claim 3, characterized in that: When the cold heading pressure of the six-sequence die is increased, the optical inspection further includes: The formed workpiece is placed on a rotatable worktable and irradiated along the axis of the formed workpiece by 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 section of the formed workpiece. The surface profile of the formed workpiece after one rotation is collected by a CCD camera, and whether the formed workpiece is qualified is judged based on the length of the laser line in the surface profile.

6. The method for manufacturing a chassis mounting welding sleeve according to claim 5, characterized in that: When judging whether the formed workpiece is qualified according to the length of the laser line in the surface profile, the method includes: When the similarity between the laser line length at each structure of the formed workpiece and the standard laser line length is greater than or equal to a similarity threshold, the formed workpiece is determined to be qualified and the formed workpiece is used as the workpiece to be finished; When the similarity between the laser line length and the standard laser line length is less than a similarity threshold, the formed workpiece is determined to be unqualified, and an abnormal workpiece processing warning is issued.

7. A chassis mounting welding sleeve, prepared according to the chassis mounting welding sleeve manufacturing method according to any one of claims 1 to 6, characterized in that: include: The welding part includes a straight-tube welding part and a flange welding part; the flange welding part adopts a flange structure, and a welding groove and a welding exhaust groove are provided on the flange. A straight-tube structure is provided under the flange head for interference fit with the lower welding plate; the straight-tube welding part is provided with a dimensional tolerance, and is welded and reinforced after interference fit with the upper welding plate; The transition area between the straight tube welding point and the flange welding point adopts a cold-formed integrally formed structure; It also includes a countersunk hole structure, which is arranged at the upper and lower ends; Also includes internal thread structure.

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