A manufacturing method of a high-precision light-weight automobile shock absorber reservoir pipe

Abstract

The application discloses a kind of automobile shock absorber technologies, to provide a kind of high-precision light-weight automobile shock absorber liquid storage pipe piece manufacturing method, its technical solution main points are as follows: S1, material pretreatment;S2, laser positioning roll welding: blank is sent into roll welding production line, laser positioning system projects weld track guide line on blank surface, is thus continuously roll forming, along guide line laser welding, real-time acquisition infrared thermal imaging data of weld pool, constructs weld pool temperature field dynamic distribution model, calculates the temperature gradient value in each 3mm of weld center line two sides, when temperature gradient value exceeds preset gradient threshold value, power and speed are automatically adjusted to maintain temperature field balance, control cylinder roundness error ≤±0.3mm, weld excess height ≤0.5mm;S3, numerical control spinning sealing;S4, double stop mouth integrated forming;S5, finishing;S6, surface treatment and deburring;S7, surface quality inspection;S8, finished product inspection and marking;The application is suitable for automobile shock absorber technical field.

Description

Technical Field

[0001] This invention relates to automotive shock absorber technology, and more specifically, to a method for manufacturing a high-precision, lightweight automotive shock absorber reservoir. Background Technology

[0002] Shock absorbers are the core damping components of automotive suspension systems, and their performance directly affects the vehicle's ride comfort, handling stability, and safety. The reservoir, as a crucial component of the shock absorber, carries the hydraulic fluid and provides structural support for the internal working cylinder; its manufacturing precision and assembly quality directly impact the overall performance and lifespan of the shock absorber.

[0003] As the automotive industry moves towards high-end and lightweight designs, especially with the widespread adoption of electronically controlled shock absorbers in mid-to-high-end and new energy vehicles, more stringent requirements are being placed on the dimensional accuracy, coaxiality, surface quality, and assemblability of liquid reservoir components. However, in existing liquid reservoir manufacturing processes, the traditional method relies on manual positioning during the coiling and welding process. This results in large fluctuations in the weld temperature field, making it difficult to consistently control roundness and weld quality, thus affecting coaxiality, dimensional accuracy, and surface quality. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a method for manufacturing a high-precision and lightweight automotive shock absorber reservoir pipe.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a manufacturing method for a high-precision lightweight automotive shock absorber reservoir pipe, comprising the following steps: S1, material pretreatment: selecting SAPH370 medium-thick steel plate as the blank, shot blasting the surface of the blank to remove oxide scale, followed by finishing and leveling, controlling the flatness tolerance of the plate after leveling to ≤0.5mm / m. 2 A laser contour scanner is used to perform a full-width contour scan on the leveled sheet material to construct a three-dimensional contour data model of the sheet material. The three-dimensional contour data model is compared point by point with a preset standard blank theoretical model to calculate the full-width thickness deviation distribution cloud map. When the thickness deviation of any area exceeds ±0.1mm, the area is marked and corresponding position information is generated. The area percentage of areas with thickness deviation exceeding ±0.1mm is counted. When the area percentage is ≥5%, the blank material is judged as unqualified and rejected; when the area percentage is <5%, the blank material is judged as qualified and transferred to S2. S2. Laser Positioning Roll Welding: Qualified blanks are fed into the roll welding production line. A laser positioning system projects a weld seam guide line onto the surface of the blank. The guide line is used as a reference for continuous rolling and forming to create a cylindrical blank. Laser welding is then carried out along the guide line. During the welding process, infrared thermal imaging data of the weld pool is collected in real time to construct a dynamic distribution model of the weld pool temperature field. The temperature gradient value within a 3mm width on both sides of the weld center line is calculated. When the temperature gradient value exceeds the preset gradient threshold, the laser power and welding speed are automatically adjusted to maintain the equilibrium of the weld pool temperature field. The roundness error of the cylindrical body after roll welding is controlled to be ≤±0.3mm and the weld reinforcement height is ≤0.5mm. S3. CNC spinning and sealing: The rolled and welded cylindrical blank is clamped on a CNC spinning machine, and the cylinder is spun and sealed with one end as the reference. During the spinning process, three rollers are fed synchronously, and the feed rate is controlled to change in a gradient decreasing curve: the feed rate is V1 in the initial stage, the feed rate decreases to 0.75V1 in the intermediate transition stage, and the feed rate decreases to 0.5V1 in the final stage. After the sealing is formed, the end of the cylinder is machined to stop the edge. After the stop is machined, the coaxiality of the cylinder is controlled to be ≤φ0.3mm and the end face runout is ≤0.05mm. S4. Double-stop integrated forming: The sealed cylinder is transferred to the stamping forming station. A special mold is used to stamp the upper and lower ends of the cylinder simultaneously to form an upper stop and a lower stop structure. During the stamping forming process, the displacement sensor built into the mold monitors the mold closing position deviation of the upper and lower molds in real time. When the mold closing position deviation exceeds ±0.1mm, the mold adaptive compensation mechanism is activated: the upper mold feed stroke is adjusted in the reverse direction with a correction amount of 40%-60% of the deviation value, and the lower mold feed stroke is adjusted synchronously with a correction amount of 20%-40% of the deviation value to ensure that the guide tolerance of the upper and lower stops is ±0.5mm. S5. Finishing: The integrally formed cylinder is sent to the CNC machining center and the functional feature surfaces on the cylinder are machined in sequence, including but not limited to positioning holes and overall length control. During the machining process, an online measurement system is used to detect the dimensions of each machining feature and feed the detection data back to the CNC system in real time. The CNC system automatically generates tool compensation parameters based on the deviation between the detection data and the theoretical value and pre-corrects the machining path of the next workpiece. S6. Surface treatment and deburring: Place the finished cylinder into the deburring equipment to remove sharp corner burrs from all edges of the cylinder. Control the chamfer of the edges after deburring to 0.5×45°. Then clean the surface of the cylinder to remove surface oil and processing residues. S7. Surface Quality Inspection: A full surface quality inspection is performed on the cylinder. A machine vision inspection system is used to scan the inner and outer surfaces of the cylinder 360°. The image recognition algorithm is used to detect whether there are defects such as rust, pits, scratches, and deformation on the surface. When any of the above defects are detected, the cylinder is determined to be a defective product and is automatically sorted to the waste bin. When all surface defect inspection items are qualified, the surface quality of the cylinder is determined to be qualified and is transferred to S8. S8. Finished Product Inspection and Marking: The final dimensional accuracy of the qualified cylinders is re-inspected. After the re-inspection is passed, the cylinders are marked with laser marking. The marking content includes the production batch number, production date and unique traceability code. After marking is completed, the cylinders are put into storage.

[0006] The present invention is further configured such that, in step S2, the method for determining the infrared thermal imaging data acquisition and temperature gradient control of the weld pool specifically includes: using the weld trajectory guide line as a reference, dividing the weld into N weld segments of equal length, each segment having a length L0 = 5mm; independently acquiring infrared thermal imaging data of the weld pool for each weld segment; constructing a two-dimensional temperature field matrix T(i,j) for that segment, where i is the pixel index along the weld direction and j is the pixel index perpendicular to the weld direction; and calculating the values ​​of each pixel on both sides of the weld centerline within that segment. The temperature gradient value within a 3mm width range is G = ∂T / ∂d, where d is the distance perpendicular to the weld direction. The gradient reference value is set to G0 = 15℃ / mm. When G ≤ 1.2G0, the temperature field of this section is considered to be balanced, and this section is recorded as a Class A section. When 1.2G0 < G ≤ 1.8G0, the section is considered to have a slight temperature gradient anomaly, and is marked as a Class B section, triggering a first-level fine adjustment: the laser power corresponding to this section is reduced to 92% of the current value, and the welding speed is increased to 1.05 times the current value. When G > 1.8G0, a severe temperature gradient anomaly is determined in this section, which is marked as a Class C section, triggering a secondary readjustment: the welding equipment continues to move without stopping, only recording the position coordinates of this Class C section; after the entire weld is completed, laser remelting repair is performed on the Class C section based on the recorded position coordinates, with the laser power for remelting repair being 105%-115% of the original laser power and the welding speed being 0.85-0.95 times the original welding speed; after the remelting repair is completed, the final temperature field is determined... The system counts the number of Class A sections (NA), Class B sections (NB), and Class C sections (NC) in the entire weld. When NC ≥ 2, the temperature field of the entire weld is considered out of control, the equipment stops and an alarm is triggered. When NC = 1 and NB ≥ 3, the temperature field of the entire weld is considered to be in a critical state. The system automatically reduces the laser power of the unwelded sections by 3% and increases the welding speed by 2%, and continues to perform welding operations on the subsequent sections. When NC = 0 and NB ≤ 2, the temperature field of the entire weld is considered to be qualified, and subsequent steps continue.

[0007] The present invention is further configured such that: in S2, the laser welding adopts a fiber laser with a laser power of 4-6kW, a welding speed of 1.5-2.5m / min, and the shielding gas is argon with a gas flow rate of 15-25L / min.

[0008] The present invention is further configured such that, in S3, during the three-roll synchronous feeding, the gradient decreasing curve of the feed rate is as follows: the feed rate V1 in the initial stage is 2.5 mm / s, the feed rate in the intermediate transition stage is 1.875 mm / s, and the feed rate in the final stage is 1.25 mm / s, with the time proportions of the three stages being 15%-25%, 40%-60%, and 25%-35%, respectively.

[0009] The present invention is further configured such that: in S7, the image recognition algorithm of the machine vision inspection system adopts a multi-scale feature fusion detection model, which includes a three-layer architecture of a shallow recognition unit, a middle analysis unit, and a deep judgment unit. The shallow recognition unit is used to identify surface pits and scratches, the middle analysis unit is used to identify surface corrosion and deformation defects, and the deep judgment unit is used to comprehensively determine whether the surface quality is qualified. When both the shallow recognition unit and the middle analysis unit determine that there are no defects, the deep judgment unit directly outputs a qualified judgment. When either the shallow recognition unit or the middle analysis unit determines that there is a suspected defect, the deep judgment unit is triggered to perform a secondary fine judgment on the suspected area. If a defect is still determined after the secondary fine judgment, an unqualified judgment is output and the defect type and location coordinates are marked.

[0010] The beneficial effects of this invention are: 1. Compared with existing technologies, the manufacturing method of the high-precision lightweight automotive shock absorber reservoir pipe of this invention significantly improves the precision and consistency of the reservoir pipe through full-process digital closed-loop control; Step S1 uses three-dimensional contour scanning and thickness deviation cloud map analysis to accurately eliminate material defects, control the quality of the blank from the source, and avoid deformation or breakage caused by uneven material in subsequent processing; Step S2 laser positioning roll welding combined with dynamic control of the molten pool temperature field effectively suppresses welding thermal deformation and ensures the roundness of the cylinder and the quality of the weld; Step S3 gradient decreasing spinning process optimizes the metal flow distribution, reduces the risk of sealing cracking, and achieves extremely high consistency in coaxiality and end face runout, effectively avoiding the risks of eccentricity and vibration; Step S4 double stop integrated stamping corrects mold deviation in real time through an adaptive compensation mechanism to ensure assembly guidance accuracy; Steps S5-S8 integrate online measurement, visual inspection and traceability identification to achieve full life cycle quality control, improve product qualification rate, and are suitable for efficient mass production of core components of high-strength lightweight automotive shock absorbers.

[0011] 2. The manufacturing method of the high-precision lightweight automotive shock absorber reservoir pipe of the present invention manages the weld seam in sections, constructs a two-dimensional temperature field matrix by combining infrared thermal imaging, accurately quantifies the gradient value G, and sets a three-level response mechanism: Class A is normal welding, Class B is fine-tuning process parameters, and Class C is fixed-point remelting after shutdown. This dynamic zoning strategy avoids the efficiency loss caused by traditional global power reduction, and at the same time prevents the microstructure deterioration caused by local overheating. The specially designed critical state judgment rule: shutdown when NC≥2, warning when NC=1 and NB≥3, realizes risk interception in advance and ensures the stability of the temperature field of the entire weld seam. This method reduces the width of the welding heat-affected zone, accurately controls the roundness error of the cylinder, and greatly improves fatigue life, especially suitable for the reliability requirements of automotive shock absorbers under high-frequency vibration conditions.

[0012] 3. In this invention, by limiting the core parameters of laser welding—power 4-6kW, speed 1.5-2.5m / min, and argon flow rate 15-25L / min—an optimal balance is achieved between processing efficiency and quality. The lower limit of 4kW power ensures penetration depth into medium-thick plates, while the upper limit of 6kW prevents burn-through. The low speed of 1.5m / min ensures sufficient metallurgical bonding, while the high speed of 2.5m / min matches the production line cycle. The argon flow rate of 15L / min prevents oxidation, while the upper limit of 25L / min prevents turbulence from entraining impurities. This combination of parameters reduces weld porosity, improves impact toughness, and reduces cylinder out-of-roundness caused by heat input. Attached Figure Description

[0013] Figure 1 This is a flowchart illustrating the manufacturing method of the high-precision lightweight automotive shock absorber reservoir pipe of the present invention.

[0014] Figure 2 This is a schematic diagram of the high-precision lightweight automotive shock absorber fluid reservoir pipe of the present invention. Detailed Implementation

[0015] Reference Figure 1-2 The manufacturing method of the high-precision lightweight automotive shock absorber reservoir pipe of the present invention will be further described in an embodiment.

[0016] For ease of explanation, spatial relative terms such as “up,” “down,” “left,” and “right” are used in the embodiments to describe the relationship of one element or feature shown in the figures relative to another element or feature. It should be understood that, in addition to the orientations shown in the figures, spatial terms are intended to include different orientations of the device in use or operation. For example, if the device in the figures is inverted, an element described as being “down” of other elements or features would be positioned “up” of those other elements or features. Therefore, the exemplary term “down” can encompass both up and down orientations. The device may be positioned in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0017] Moreover, relational terms such as “first” and “second” are used merely to distinguish one component from another that has the same name, without necessarily requiring or implying any such actual relationship or order between the components.

[0018] Figures 1 to 2 The method for manufacturing a high-precision, lightweight automotive shock absorber reservoir pipe includes the following steps: S1, material pretreatment: Select SAPH370 medium-thick steel plate as the blank, shot blast the surface of the blank to remove oxide scale, and then perform fine finishing and leveling, controlling the flatness tolerance of the plate after leveling to ≤0.5mm / m. 2 A laser contour scanner is used to perform a full-width contour scan on the leveled sheet material to construct a three-dimensional contour data model of the sheet material. The three-dimensional contour data model is compared point by point with a preset standard blank theoretical model to calculate the full-width thickness deviation distribution cloud map. When the thickness deviation of any area exceeds ±0.1mm, the area is marked and corresponding position information is generated. The area percentage of areas with thickness deviation exceeding ±0.1mm is counted. When the area percentage is ≥5%, the blank material is judged as unqualified and rejected; when the area percentage is <5%, the blank material is judged as qualified and transferred to S2. S2. Laser Positioning Roll Welding: Qualified blanks are fed into the roll welding production line. A laser positioning system projects a weld seam guide line onto the surface of the blank. The guide line is used as a reference for continuous rolling and forming to create a cylindrical blank. Laser welding is then carried out along the guide line. During the welding process, infrared thermal imaging data of the weld pool is collected in real time to construct a dynamic distribution model of the weld pool temperature field. The temperature gradient value within a 3mm width on both sides of the weld center line is calculated. When the temperature gradient value exceeds the preset gradient threshold, the laser power and welding speed are automatically adjusted to maintain the equilibrium of the weld pool temperature field. The roundness error of the cylindrical body after roll welding is controlled to be ≤±0.3mm and the weld reinforcement height is ≤0.5mm. S3. CNC spinning and sealing: The rolled and welded cylindrical blank is clamped on a CNC spinning machine, and the cylinder is spun and sealed with one end as the reference. During the spinning process, three rollers are fed synchronously, and the feed rate is controlled to change in a gradient decreasing curve: the feed rate is V1 in the initial stage, the feed rate decreases to 0.75V1 in the intermediate transition stage, and the feed rate decreases to 0.5V1 in the final stage. After the sealing is formed, the end of the cylinder is machined to stop the edge. After the stop is machined, the coaxiality of the cylinder is controlled to be ≤φ0.3mm and the end face runout is ≤0.05mm. S4. Double-stop integrated forming: The sealed cylinder is transferred to the stamping forming station. A special mold is used to stamp the upper and lower ends of the cylinder simultaneously to form an upper stop and a lower stop structure. During the stamping forming process, the displacement sensor built into the mold monitors the mold closing position deviation of the upper and lower molds in real time. When the mold closing position deviation exceeds ±0.1mm, the mold adaptive compensation mechanism is activated: the upper mold feed stroke is adjusted in the reverse direction with a correction amount of 40%-60% of the deviation value, and the lower mold feed stroke is adjusted synchronously with a correction amount of 20%-40% of the deviation value to ensure that the guide tolerance of the upper and lower stops is ±0.5mm. S5. Finishing: The integrally formed cylinder is sent to the CNC machining center and the functional feature surfaces on the cylinder are machined in sequence, including but not limited to positioning holes and overall length control. During the machining process, an online measurement system is used to detect the dimensions of each machining feature and feed the detection data back to the CNC system in real time. The CNC system automatically generates tool compensation parameters based on the deviation between the detection data and the theoretical value and pre-corrects the machining path of the next workpiece. S6. Surface treatment and deburring: Place the finished cylinder into the deburring equipment to remove sharp corner burrs from all edges of the cylinder. Control the chamfer of the edges after deburring to 0.5×45°. Then clean the surface of the cylinder to remove surface oil and processing residues. S7. Surface Quality Inspection: A full surface quality inspection is performed on the cylinder. A machine vision inspection system is used to scan the inner and outer surfaces of the cylinder 360°. The image recognition algorithm is used to detect whether there are defects such as rust, pits, scratches, and deformation on the surface. When any of the above defects are detected, the cylinder is determined to be a defective product and is automatically sorted to the waste bin. When all surface defect inspection items are qualified, the surface quality of the cylinder is determined to be qualified and is transferred to S8. S8. Finished Product Inspection and Marking: The final dimensional accuracy of the qualified cylinders shall be re-inspected. After the re-inspection is passed, the cylinders shall be marked with laser marking. The marking content includes the production batch number, production date and unique traceability code. After marking is completed, the cylinders shall be put into storage. The end-to-end digital closed-loop control significantly improves the precision and consistency of the liquid storage pipe fittings; Step S1 uses 3D contour scanning and thickness deviation cloud map analysis to accurately eliminate material defects, control the quality of the blank from the source, and avoid deformation or breakage caused by uneven material in subsequent processing; Step S2 laser positioning roll welding combined with dynamic control of the molten pool temperature field effectively suppresses welding thermal deformation and ensures the roundness of the cylinder and the quality of the weld; Step S3 gradient decreasing spinning process optimizes the distribution of metal flow lines, reduces the risk of sealing cracking, and achieves extremely high consistency in coaxiality and end face runout, effectively avoiding the risks of eccentricity and vibration; Step S4 double stop integrated stamping uses an adaptive compensation mechanism to correct mold deviations in real time and ensure assembly guidance accuracy; Steps S5-S8 integrate online measurement, visual inspection, and traceability identification to achieve full life cycle quality control, improve product qualification rate, and are suitable for the efficient mass production of core components of high-strength lightweight automotive shock absorbers.

[0019] In step S2, the method for acquiring infrared thermal imaging data of the weld pool and determining temperature gradient control specifically includes: using the weld trajectory guide line as a reference, dividing the weld into N weld segments of equal length, each segment having a length L0 = 5mm; independently acquiring infrared thermal imaging data of the weld pool for each weld segment; constructing a two-dimensional temperature field matrix T(i,j) for that segment, where i is the pixel index along the weld direction and j is the pixel index perpendicular to the weld direction; and calculating the range of 3mm width on both sides of the weld centerline within that segment. The temperature gradient value within the section is G = ∂T / ∂d, where d is the distance perpendicular to the weld direction. The gradient reference value is set to G0 = 15℃ / mm. When G ≤ 1.2G0, the temperature field of the section is considered to be balanced, and the section is recorded as a Class A section. When 1.2G0 < G ≤ 1.8G0, the section is considered to have a slight temperature gradient anomaly, and is marked as a Class B section, triggering a first-level fine-tuning: the laser power corresponding to the section is reduced to 92% of the current value, and the welding speed is increased to 1.05 times the current value. When G > 1... At 8G0, a severe temperature gradient anomaly is detected in this section, which is marked as a Class C section, triggering a secondary readjustment: the welding equipment continues to move without stopping, only recording the position coordinates of this Class C section; after the entire weld is completed, laser remelting repair is performed on the Class C section based on the recorded position coordinates, with the laser power for remelting repair being 105%-115% of the original laser power and the welding speed being 0.85-0.95 times the original welding speed; after the remelting repair is completed, the number of Class A sections (NA), Class B sections (NB), and Class C sections (NC) in the entire weld are counted based on the final formed temperature field data. When NC≥2, the temperature field of the entire weld is deemed out of control, the equipment stops and an alarm is triggered; when NC=1 and NB≥3, the temperature field of the entire weld is deemed to be in a critical state, the system automatically reduces the overall laser power of the unwelded sections by 3% and increases the overall welding speed by 2%, and continues to execute the welding operation of the subsequent sections; when NC=0 and NB≤2, the temperature field of the entire weld is deemed to be qualified, and subsequent steps continue; By segmenting and managing the weld seam, and constructing a two-dimensional temperature field matrix using infrared thermal imaging, the gradient value G is precisely quantified, and a three-level response mechanism is established: Class A is normal welding, Class B is fine-tuning process parameters, and Class C is fixed-point remelting after shutdown. This dynamic zoning strategy avoids the efficiency loss caused by traditional global power reduction, while preventing microstructural degradation caused by local overheating. The specially designed critical state judgment rules—NC≥2 shutdown, NC=1 and NB≥3 early warning—achieve risk interception in advance and ensure the stability of the temperature field of the entire weld seam. This method reduces the width of the weld heat-affected zone, accurately controls the roundness error of the cylinder, and significantly improves fatigue life, making it particularly suitable for the reliability requirements of automotive shock absorbers under high-frequency vibration conditions.

[0020] In S2, the laser welding uses a fiber laser with a laser power of 4-6kW, a welding speed of 1.5-2.5m / min, and the shielding gas is argon with a gas flow rate of 15-25L / min. By limiting the core parameters of laser welding—power 4-6kW, speed 1.5-2.5m / min, and argon flow rate 15-25L / min—an optimal balance is achieved between processing efficiency and quality. The lower limit of 4kW power ensures penetration depth into medium-thick plates, while the upper limit of 6kW prevents burn-through. The low speed of 1.5m / min ensures sufficient metallurgical bonding, while the high speed of 2.5m / min matches the production line cycle. The argon flow rate of 15L / min prevents oxidation, while the upper limit of 25L / min prevents turbulence from entraining impurities. This combination of parameters reduces weld porosity, improves impact toughness, and reduces cylinder out-of-roundness caused by heat input.

[0021] In S3, during the three-roll synchronous feeding, the gradient decrease curve of the feed rate is as follows: the feed rate V1 = 2.5 mm / s in the initial stage, the feed rate in the intermediate transition stage = 1.875 mm / s, and the feed rate in the final stage = 1.25 mm / s, with the time proportions of the three stages being 15%-25%, 40%-60%, and 25%-35%, respectively. The gradient decrease curve of the three-roll synchronous feed precisely matches the plastic flow law of the material; the initial high-speed stage enables rapid forming and reduces the mold contact time; the mid-term deceleration buffers metal rebound and avoids wrinkles; the final low-speed pressure holding enhances the sealing density; the time allocation further optimizes the stress release path, making the hardness gradient of the spinning zone transition smoothly and eliminating local stress concentration; this process improves the tensile strength of the sealing part, far exceeding that of traditional constant-speed spinning parts; at the same time, the coaxiality ≤φ0.3mm precision control eliminates the need for subsequent correction processes and shortens the processing cycle of a single piece.

[0022] In S7, the image recognition algorithm of the machine vision inspection system adopts a multi-scale feature fusion detection model. This model includes a three-layer architecture: a shallow recognition unit, a middle analysis unit, and a deep judgment unit. The shallow recognition unit is used to identify surface pits and scratches, the middle analysis unit is used to identify surface corrosion and deformation defects, and the deep judgment unit is used to comprehensively determine whether the surface quality is qualified. When both the shallow recognition unit and the middle analysis unit determine that there are no defects, the deep judgment unit directly outputs a qualified judgment. When either the shallow recognition unit or the middle analysis unit determines that there is a suspected defect, the deep judgment unit is triggered to perform a secondary fine judgment on the suspected area. If a defect is still determined after the secondary fine judgment, an unqualified judgment is output and the defect type and location coordinates are marked. The multi-scale feature fusion detection model breaks through the limitations of traditional visual detection; shallow units focus on micro-defects: pits, scratches, medium-layer units capture macro-anomalies: corrosion, deformation, and deep units make comprehensive judgments to avoid misjudgments; this layered processing mechanism improves detection speed and greatly reduces the false negative rate; in particular, suspected defects trigger deep secondary discrimination, effectively distinguishing between real defects and suspected defects, reducing the false rejection rate; combined with 360° full surface scanning, it ensures the sealing safety of the vibration damper in a high-pressure oil environment.

[0023] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any ordinary changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for manufacturing a high-precision, lightweight automotive shock absorber fluid reservoir, characterized in that: Includes the following steps: S1. Material Pretreatment: SAPH370 medium-thick steel plate is selected as the billet. The surface of the billet is shot-blasted to remove oxide scale, followed by finishing and leveling. The flatness tolerance of the plate after leveling is controlled to be ≤0.5mm / m. 2 A laser contour scanner is used to perform a full-width contour scan on the leveled sheet material to construct a three-dimensional contour data model of the sheet material. The three-dimensional contour data model is compared point by point with a preset standard blank theoretical model to calculate the full-width thickness deviation distribution cloud map. When the thickness deviation of any area exceeds ±0.1mm, the area is marked and corresponding position information is generated. The area percentage of areas with thickness deviation exceeding ±0.1mm is counted. When the area percentage is ≥5%, the blank material is judged as unqualified and rejected; when the area percentage is <5%, the blank material is judged as qualified and transferred to S2. S2. Laser Positioning Roll Welding: Qualified blanks are fed into the roll welding production line. A laser positioning system projects a weld seam guide line onto the surface of the blank. The guide line is used as a reference for continuous rolling and forming to create a cylindrical blank. Laser welding is then carried out along the guide line. During the welding process, infrared thermal imaging data of the weld pool is collected in real time to construct a dynamic distribution model of the weld pool temperature field. The temperature gradient value within a 3mm width on both sides of the weld center line is calculated. When the temperature gradient value exceeds the preset gradient threshold, the laser power and welding speed are automatically adjusted to maintain the equilibrium of the weld pool temperature field. The roundness error of the cylindrical body after roll welding is controlled to be ≤±0.3mm and the weld reinforcement height is ≤0.5mm. S3. CNC spinning and sealing: The rolled and welded cylindrical blank is clamped on a CNC spinning machine, and the cylinder is spun and sealed with one end as the reference. During the spinning process, three rollers are fed synchronously, and the feed rate is controlled to change in a gradient decreasing curve: the feed rate is V1 in the initial stage, the feed rate decreases to 0.75V1 in the intermediate transition stage, and the feed rate decreases to 0.5V1 in the final stage. After the sealing is formed, the end of the cylinder is machined to stop the edge. After the stop is machined, the coaxiality of the cylinder is controlled to be ≤φ0.3mm and the end face runout is ≤0.05mm. S4. Double-stop integrated forming: The sealed cylinder is transferred to the stamping forming station. A special mold is used to stamp the upper and lower ends of the cylinder simultaneously to form an upper stop and a lower stop structure. During the stamping forming process, the displacement sensor built into the mold monitors the mold closing position deviation of the upper and lower molds in real time. When the mold closing position deviation exceeds ±0.1mm, the mold adaptive compensation mechanism is activated: the upper mold feed stroke is adjusted in the reverse direction with a correction amount of 40%-60% of the deviation value, and the lower mold feed stroke is adjusted synchronously with a correction amount of 20%-40% of the deviation value to ensure that the guide tolerance of the upper and lower stops is ±0.5mm. S5. Finishing: The integrally formed cylinder is sent to the CNC machining center and the functional feature surfaces on the cylinder are machined in sequence, including but not limited to positioning holes and overall length control. During the machining process, an online measurement system is used to detect the dimensions of each machining feature and feed the detection data back to the CNC system in real time. The CNC system automatically generates tool compensation parameters based on the deviation between the detection data and the theoretical value and pre-corrects the machining path of the next workpiece. S6. Surface treatment and deburring: Place the finished cylinder into the deburring equipment to remove sharp corner burrs from all edges of the cylinder. Control the chamfer of the edges after deburring to 0.5×45°. Then clean the surface of the cylinder to remove surface oil and processing residues. S7. Surface Quality Inspection: A full surface quality inspection is performed on the cylinder. A machine vision inspection system is used to scan the inner and outer surfaces of the cylinder 360°. The image recognition algorithm is used to detect whether there are defects such as rust, pits, scratches, and deformation on the surface. When any of the above defects are detected, the cylinder is determined to be a defective product and is automatically sorted to the waste bin. When all surface defect inspection items are qualified, the surface quality of the cylinder is determined to be qualified and is transferred to S8. S8. Finished Product Inspection and Marking: The final dimensional accuracy of the qualified cylinders is re-inspected. After the re-inspection is passed, the cylinders are marked with laser marking. The marking content includes the production batch number, production date and unique traceability code. After marking is completed, the cylinders are put into storage.

2. The manufacturing method of a high-precision lightweight automotive shock absorber reservoir pipe according to claim 1, characterized in that, In step S2, the method for acquiring infrared thermal imaging data of the weld pool and determining temperature gradient control specifically includes: using the weld trajectory guide line as a reference, dividing the weld into N weld segments of equal length, each segment having a length L0 = 5mm; independently acquiring infrared thermal imaging data of the weld pool for each weld segment; constructing a two-dimensional temperature field matrix T(i,j) for that segment, where i is the pixel index along the weld direction and j is the pixel index perpendicular to the weld direction; and calculating the range of 3mm width on both sides of the weld centerline within that segment. The temperature gradient value within the section is G = ∂T / ∂d, where d is the distance perpendicular to the weld direction. The gradient reference value is set to G0 = 15℃ / mm. When G ≤ 1.2G0, the temperature field of the section is considered to be balanced, and the section is recorded as a Class A section. When 1.2G0 < G ≤ 1.8G0, the section is considered to have a slight temperature gradient anomaly, and is marked as a Class B section, triggering a first-level fine-tuning: the laser power corresponding to the section is reduced to 92% of the current value, and the welding speed is increased to 1.05 times the current value. When G > 1... At 8G0, a severe temperature gradient anomaly is detected in this section, which is marked as a Class C section, triggering a secondary readjustment: the welding equipment continues to move without stopping, only recording the position coordinates of this Class C section; after the entire weld is completed, laser remelting repair is performed on the Class C section based on the recorded position coordinates, with the laser power for remelting repair being 105%-115% of the original laser power and the welding speed being 0.85-0.95 times the original welding speed; after the remelting repair is completed, the number of Class A sections (NA), Class B sections (NB), and Class C sections (NC) in the entire weld are counted based on the final formed temperature field data. When NC≥2, the temperature field of the entire weld is deemed out of control, the equipment stops and an alarm is triggered; when NC=1 and NB≥3, the temperature field of the entire weld is deemed to be in a critical state, the system automatically reduces the overall laser power of the unwelded sections by 3% and increases the overall welding speed by 2%, and continues to execute the welding operation of the subsequent sections; when NC=0 and NB≤2, the temperature field of the entire weld is deemed to be qualified, and subsequent steps continue.

3. The manufacturing method of a high-precision lightweight automotive shock absorber reservoir pipe according to claim 1, characterized in that, In step S2, the laser welding uses a fiber laser with a laser power of 4-6kW, a welding speed of 1.5-2.5m / min, and the shielding gas is argon with a gas flow rate of 15-25L / min.

4. The manufacturing method of a high-precision lightweight automotive shock absorber reservoir pipe according to claim 1, characterized in that, In S3, during the three-roll synchronous feeding, the gradient decrease curve of the feed rate is as follows: the feed rate V1 = 2.5 mm / s in the initial stage, the feed rate in the intermediate transition stage = 1.875 mm / s, and the feed rate in the final stage = 1.25 mm / s. The time proportions of the three stages are 15%-25%, 40%-60%, and 25%-35%, respectively.

5. The manufacturing method of a high-precision lightweight automotive shock absorber reservoir pipe according to claim 1, characterized in that, In S7, the image recognition algorithm of the machine vision inspection system adopts a multi-scale feature fusion detection model. This model includes a three-layer architecture: a shallow recognition unit, a middle analysis unit, and a deep judgment unit. The shallow recognition unit is used to identify surface pits and scratches, the middle analysis unit is used to identify surface corrosion and deformation defects, and the deep judgment unit is used to comprehensively determine whether the surface quality is qualified. When both the shallow recognition unit and the middle analysis unit determine that there are no defects, the deep judgment unit directly outputs a qualified judgment. When any layer in the shallow identification unit or the middle analysis unit determines that there is a suspected defect, the deep judgment unit is triggered to perform a second fine judgment on the suspected area. If the defect is still determined after the second fine judgment, an unqualified judgment is output and the defect type and location coordinates are marked.

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