A molding process for a control arm bracket of an automobile

Abstract

The application discloses a forming process of a control arm bracket of an automobile, and belongs to the technical field of machining of automobile chassis parts, and comprises the following procedures: blanking, stretching, and first punching and trimming, wherein, in the blanking procedure, a blank is punched from a plate, and a positioning hole is formed on the blank, the positioning hole serving as a common positioning reference of all subsequent procedures; in the stretching procedure, the blank is stretched to form a basic contour of the control arm bracket by positioning the positioning hole; and in the first punching and trimming procedure, the stretched blank is trimmed and punched, and a pre-punching hole is formed by the punching. The application can effectively solve the problem of cracking and thinning of the high flanging of the tail part of the control arm bracket, and improve the positioning accuracy and forming stability of the product.

Description

Technical Field

[0001] This invention relates to the field of automotive chassis component processing technology, and in particular to a molding process for an automotive control arm bracket. Background Technology

[0002] As a key connecting component of the automotive chassis suspension system, the structural strength and forming precision of the control arm bracket directly affect the overall vehicle's driving safety and reliability. Most ordinary passenger cars use high-strength steel plates for stamping. This involves using molds to press high-strength steel plates through multiple stamping processes such as blanking, bending, and stretching to create the bracket shape. After trimming, punching, and shaping, multiple stamped parts are welded into a single bracket, and finally, surface treatment is applied. This process is simple, suitable for mass production, and has relatively low costs.

[0003] Relevant prior art, such as Chinese patent application "A Cold Stamping Manufacturing Process for Automobile Chassis Parts," publication number CN118543746A, discloses a process including the following steps: obtaining a flat blank with positioning holes; performing a first stretching to obtain a first forming part and a second forming part, including curved sections connected together; performing a second stretching to reduce the radius of the first forming part to form a third forming part, while the curved sections and the second forming part are stretched through the middle to form a fourth forming part; performing a third stretching to increase the height of the third and fourth forming parts to form a fifth forming part and a sixth forming part, respectively; and performing blanking and folding to obtain the desired control arm product. The beneficial effects of the above patent application are: the above process method can obtain a cold-stamped control arm product that meets the quality requirements. Compared with traditional methods, it can effectively avoid cracking during the stamping process, thereby effectively improving the product qualification rate.

[0004] Due to the varying shapes, dimensions, and thicknesses of stamped parts, the processing and assembly techniques for stamping dies differ depending on the specific conditions. Currently, the design of control arm bracket products has become more complex, making their processing more challenging. To meet assembly and connection requirements, the tail of the control arm bracket is typically designed with a high flange structure. During the forming process, this area experiences significant deformation and limited material elongation, making it highly susceptible to problems such as excessive material thinning, localized cracking, and poor forming stability—a persistent technological challenge in the industry. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a molding process for an automotive control arm bracket, which can effectively solve the problem of cracking and thinning at the high flange of the control arm bracket, and improve the positioning accuracy and molding stability of the product.

[0006] The technical solution adopted in this invention is: a molding process for an automotive control arm bracket, comprising the following steps: blanking, stretching, and first punching and trimming. In the blanking process, the sheet metal is punched to form a blank, and a positioning hole is formed on the blank. The positioning hole serves as a common positioning reference for all subsequent processes. In the stretching process, the blank is positioned using the positioning holes, and the blank is stretched to form the basic outline of the control arm bracket. The tail area of ​​the control arm bracket is stretched to obtain the material extension in advance. In the first punching and trimming process, the stretched blank is trimmed and punched, and the punching forms a pre-punched hole.

[0007] Compared with existing technologies, the advantages of this invention are that it forms a unique positioning hole during the blanking stage and uses it as a common positioning reference for all subsequent processes such as stretching, first punching, and trimming. Compared with multi-reference positioning or forming methods without a fixed reference, a single reference can avoid the cumulative errors caused by the conversion of positioning references between processes, too many positioning holes, or positional deviations. This significantly improves the positioning stability of the blank during continuous forming, reduces problems such as blank offset, torsion, and misalignment, and helps improve the overall dimensional accuracy and batch consistency of the control arm support.

[0008] While stretching and forming the basic outline of the control arm bracket, the tail area of ​​the bracket is specifically stretched, so that the sheet material in this area undergoes plastic deformation and material extension before the flanging process. This method can pre-allocate materials and release local stress, avoiding excessive thinning and cracking due to concentrated deformation and insufficient material extension during flanging. It improves the forming limit of high-flanging structures from the forming path and enhances the reliability of product forming.

[0009] This invention employs a process sequence of first stretching to form the overall contour, followed by the first punching and trimming. First, stretching completes the main structural form, giving the blank a stable spatial shape. Then, trimming and punching perform preliminary calibration of the contour dimensions and hole positions, avoiding problems such as hole position misalignment and shape distortion caused by machining holes in an unstable contour state. This results in a more uniform stress distribution and stronger coordination between processes. The pre-punched holes formed in the first punching and trimming process not only provide a technological basis for subsequent hole enlargement and forming processes but also serve as auxiliary positioning and dimensional references, allowing subsequent processes to be based on the stable structural shape. This further ensures the relative positional accuracy between various features and improves the overall forming quality.

[0010] The entire process route of this invention is designed around the common industry problems of easy cracking and thinning of the high flange at the tail of the control arm bracket. Through a combination of pre-extension, stable positioning and step-by-step molding, the key defects are targeted and suppressed without increasing the complexity of the process and mold structure. The process is simple and reliable and suitable for mass industrial production.

[0011] In some embodiments of the present invention, the blank formed in the blanking process includes an upper edge, a lower edge, an outer edge, and an inner edge, wherein the outer edge is a zigzag segment with a rounded transition, and the positioning hole is provided near the bend of the outer edge.

[0012] The outer edge uses a rounded transition line segment, which can mitigate stress concentration during the forming process and reduce the risk of edge cracking. The positioning holes are set near the bend, which can use the area with better rigidity of the blank as a positioning reference, reduce the deformation of the positioning holes, and improve the positioning stability of the entire process.

[0013] In this invention, for ease of description, the figures in the specification are used as references. Figure 2 Using the top edge, bottom edge, outer edge, and inner edge as a reference does not imply the actual direction of the product during use.

[0014] In some embodiments of the present invention, during the stretching process, the positioning hole is used for positioning, and the blank is stretched to form a first boss, a second boss, and a third boss. The positioning hole is located on the first boss, and the third boss is a semi-closed boss structure with one side open. The third boss includes a top surface with a planar structure, a flanged pre-forming surface that is raised relative to the blank, and a connecting curved surface that connects the top surface and the flanged pre-forming surface. The flanged pre-forming surface is located in the flanged area at the tail of the control arm bracket.

[0015] This invention designs the third boss as a semi-enclosed boss structure with one side open. This retains the effective binding and guiding effect of the semi-enclosed structure on the material, ensuring the boss's forming height and dimensional accuracy. The one-sided open design eliminates the risks of material accumulation and tearing that are common in fully enclosed structures, achieving a balance between forming accuracy and material flowability. The flange pre-forming surface within the third boss provides sufficient material extension for the tail flange during the stretching stage. Combined with the guiding effect of the one-sided open structure, this ensures smoother and more uniform material flow during the flange process, fundamentally solving the industry pain point of excessive material thinning and localized cracking in high flange areas. Simultaneously, the smooth transition between the top surface and the flange pre-forming surface through a connecting curved surface effectively disperses concentrated stress during the forming process, avoiding the risk of sharp-corner cracks and further improving the forming reliability and structural strength of the part.

[0016] By placing the positioning hole on the first boss, which has strong structural rigidity and small deformation, the stability and deformation resistance of the positioning datum throughout the entire process are greatly improved, effectively avoiding dimensional deviations caused by datum deformation.

[0017] In some embodiments of the present invention, in the first punching and trimming process, the upper edge of the blank is trimmed, and a pre-punched hole is obtained by punching a hole at the second boss.

[0018] This invention trims the upper edge to remove irregular excess material caused by stretching, providing a regular foundation for subsequent flanging and side trimming. Punching a hole at the second boss utilizes a structurally stable area for pre-punching, resulting in higher hole position accuracy. Pre-punching provides a basis for subsequent hole enlargement, avoiding deformation and dimensional deviations caused by directly punching a large hole in one go.

[0019] In some embodiments of the present invention, after the first punching and trimming process, a flanging process, a first side trimming process, a second punching and trimming process, a second side trimming process, a third side trimming process, punching, a first shaping process, and a second shaping process are performed; after multiple processes, the blank is gradually formed into a control arm bracket part.

[0020] This invention employs a step-by-step progressive molding process, applying deformation gradually to avoid cracking and springback caused by excessive deformation in a single step. Multiple side trimming, punching, and shaping processes allow for layer-by-layer dimensional correction and stress relief, improving part precision. The invention features a clear process logic and well-defined division of labor, facilitating mold design and automated production. The blank is progressively formed into parts, ensuring strong process control and improving the overall finished product qualification rate.

[0021] In some embodiments of the present invention, in the flanging process, the blank is positioned using the positioning hole, the upper edge of the blank is flanged upwards, and the outer and inner edges of the blank are flanged downwards. In the first side trimming process, the workpiece after flanging is positioned using the positioning hole, and the outer and inner sides of the flanged workpiece are trimmed.

[0022] This invention uses the single positioning hole from the blanking stage as a unified positioning reference in the flanging process, ensuring that the blank does not shift during multi-directional flanging. This effectively guarantees the accuracy of flanging height, flanging angle, and the relative position between each flanging structure, significantly improving the dimensional consistency and assembly reliability of the product. Simultaneously, by performing flanging processing in different directions on the upper, outer, and inner edges of the blank, a one-time forming of complex three-dimensional flanging structures is achieved, simplifying the process and improving processing efficiency. Immediately after the flanging process, side trimming is performed to promptly remove irregular edges, excess material, and burrs generated during flanging. This not only makes the workpiece edge contour more regular and aesthetically pleasing but also provides a stable and clean reference base for subsequent processing steps, further ensuring the stability of the overall processing quality.

[0023] In some embodiments of the present invention, in the second punching and trimming process, the workpiece is positioned using the positioning hole, the top surface of the third boss is cut off, the outer and inner sides after flanging are further trimmed, and a side hole is punched on the inner side after flanging.

[0024] This invention ensures accurate relative positioning between the independent features of top surface removal, contour trimming, and side hole machining by continuing to use the unique positioning hole for positioning in the second punching and trimming process, thus avoiding feature offset. Removing the top surface of the third boss effectively eliminates the process transition structure left over from stretching and flanging, releasing the accumulated forming internal stress in this area and improving the internal structure of the workpiece. Simultaneously, further trimming of the outer and inner edges after flanging optimizes the workpiece's dimensions layer by layer, making the contour shape closer to the final product design requirements. Machining the side hole on the already formed and structurally stable inner edge, relying on the previously established stable flanging structure as a processing foundation, effectively ensures the positional accuracy and hole shape quality of the side hole, significantly improving the assembly performance of the final part.

[0025] In some embodiments of the present invention, in the second side trimming process, the workpiece is positioned using the positioning hole, and the outer part of the connecting surface of the third boss and the top surface is cut off. In the third side trimming process, the workpiece is positioned using the positioning hole, and the inner part of the connecting surface of the third boss and the top surface is cut off, so that the connecting surface of the third boss is completely cut off.

[0026] This invention employs a phased, step-by-step removal strategy for the connecting surface of the third boss. First, the outer portion of the connecting surface is removed, followed by the inner portion. This step-by-step removal method effectively avoids severe workpiece vibration, displacement, or edge burrs caused by large single-cutting operations, ensuring the smoothness and safety of the machining process. Simultaneously, by performing three consecutive side trimming operations to refine different sides and transition surfaces of the workpiece layer by layer, refined machining of complex contours is achieved. This gradually eliminates machining errors, ensuring the workpiece's dimensions accurately approach design requirements. This guarantees the continuity, regularity, and dimensional consistency of the final part's contour, significantly improving the part's appearance quality and structural precision.

[0027] In some embodiments of the present invention, during the punching process, the workpiece is positioned using the positioning hole, a through hole is machined on the surface of the workpiece, and the original positioning hole and the pre-punched hole are further enlarged to form an installation hole.

[0028] In the punching process, this invention relies on a unique positioning hole as a unified positioning benchmark for processing, ensuring the accurate positional relationship between the new through hole and the original hole system and the overall structure. In particular, by processing the mounting hole by expanding the hole around the original positioning hole and the pre-punched hole, compared with directly punching a large diameter hole, the existing hole position is used as a guide, avoiding the offset, eccentricity or deformation of the new hole position during processing, which significantly improves the positional accuracy of the mounting hole. At the same time, the hole expansion processing method can make the hole wall cutting more uniform and the hole shape more regular. The hole wall quality is far superior to that of direct punching, effectively ensuring the fitting accuracy between the mounting hole and the matching component, and improving the final assembly reliability and performance of the part.

[0029] In some embodiments of the present invention, the workpiece's outline, flange height, and flatness are initially shaped in the first shaping process. In the second shaping process, the workpiece undergoes final finishing and calibration to eliminate forming stress and ensure dimensional accuracy, thereby obtaining a finished control arm bracket that meets the requirements.

[0030] This invention employs a two-stage, step-by-step forming process. The first forming stage performs preliminary correction and adjustment of the workpiece's outline, flange height, and flatness, significantly correcting accumulated dimensional deviations from previous processes and laying a solid dimensional foundation for final finishing. This effectively avoids rigid damage or flange collapse caused by excessive pressure during a single forming stage. The second forming stage then performs final finishing calibration, further correcting dimensional errors and effectively eliminating residual forming stress from previous multi-stage processes. This suppresses workpiece springback and ensures that the part's dimensions and geometric tolerances strictly conform to design standards. The result is a structurally stable and precision-compliant control arm bracket, significantly improving the dimensional stability and reliability of the part during vehicle use.

[0031] Based on common knowledge in the field, the above-described embodiments can be combined arbitrarily. Attached Figure Description

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and preferred embodiments. However, those skilled in the art will understand that these drawings are drawn only for the purpose of explaining the preferred embodiments and therefore should not be construed as limiting the scope of the invention. Furthermore, unless specifically indicated, the drawings are only schematic representations of the composition or structure of the described objects and may contain exaggerated depictions, and the drawings are not necessarily drawn to scale.

[0033] Figure 1 This is a flowchart illustrating the overall process flow of the present invention. Figure 2 This is a schematic diagram of the blank structure after blanking in this invention; Figure 3This is a schematic diagram of the stretched structure in this invention; Figure 4 This is a schematic diagram of the structure after the first punching and trimming in this invention; Figure 5 This is a schematic diagram of the structure after the flange is turned up in this invention; Figure 6 This is a schematic diagram of the structure after the first side trimming in this invention; Figure 7 This is a schematic diagram of the second punching and trimming structure in this invention; Figure 8 This is a schematic diagram of the second side trimming structure in this invention; Figure 9 This is a schematic diagram of the third side trimming structure in this invention; Figure 10 This is a schematic diagram of the structure after punching in this invention; Figure 11 This is a schematic diagram of the structure after the first shaping in this invention; Figure 12 This is a schematic diagram of the structure after the second shaping in this invention; Figure 13 This is a drawing of the final product of the present invention.

[0034] The specific annotations in the attached drawings are as follows: 1. Upper edge; 2. Lower edge; 3. Outer edge; 4. Inner edge; 5. First boss; 6. Second boss; 7. Third boss; 71. Top surface; 72. Connecting curved surface; 73. Flanged pre-formed surface; 8. Positioning hole; 9. Pre-punched hole; 10. Side hole; 11. Through hole; 12. Mounting hole. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings.

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0037] A molding process for an automotive control arm bracket, as described in Example 1. Figures 1 to 4 As shown: The process includes the following steps: blanking, stretching, and first punching and trimming.

[0038] In the blanking process, the sheet metal is punched to form a blank, and a positioning hole 8 is formed on the blank. The positioning hole 8 serves as a common positioning reference for all subsequent processes. In this invention, a unique positioning hole 8 is formed at the blanking stage and serves as a common positioning reference for all subsequent processes such as stretching, first punching, and trimming. Compared with forming methods with multiple references or no fixed reference, a single reference can avoid the cumulative errors caused by the conversion of positioning references between processes, too many positioning holes 8, or positional deviations. This significantly improves the positioning stability of the blank during continuous forming, reduces problems such as blank offset, torsion, and misalignment, and helps improve the overall dimensional accuracy and batch consistency of the control arm bracket.

[0039] In the stretching process, the blank is positioned using the positioning holes 8 to stretch and form the basic outline of the control arm bracket. The tail area of ​​the control arm bracket is stretched to pre-extract the material. Simultaneously with stretching the basic outline of the control arm bracket, the tail area is specifically stretched to induce plastic deformation and material extension in this area before the flanging process. This method allows for pre-allocation of material and release of localized stress, preventing excessive thinning and cracking during flanging due to concentrated deformation and insufficient material extension. It also improves the forming limit of high-flanging structures from the forming path perspective, enhancing product forming reliability.

[0040] In the first punching and trimming process, the stretched blank is trimmed and punched, forming pre-punched holes 9. This invention employs a process sequence of first stretching to form the overall contour, followed by the first punching and trimming. First, stretching completes the main structural form, giving the blank a stable spatial shape. Then, trimming and punching are used to preliminarily calibrate the contour dimensions and hole positions, avoiding problems such as hole position offset and shape distortion caused by machining holes in an unstable contour state. This results in a more uniform stress distribution and stronger coordination between processes. The pre-punched holes 9 formed in the first punching and trimming process not only provide a technological basis for subsequent hole enlargement and forming processes, but also serve as auxiliary positioning and dimensional references, enabling subsequent processes to be based on the stable structural shape, further ensuring the relative positional accuracy between various features and improving the overall forming quality.

[0041] The entire process route of this invention is designed around the common industry problems of easy cracking and thinning of the high flange at the tail of the control arm bracket. Through a combination of pre-extension, stable positioning and step-by-step molding, the key defects are targeted and suppressed without increasing the complexity of the process and mold structure. The process is simple and reliable and suitable for mass industrial production.

[0042] Example 2, as Figures 1 to 13As shown, the blank formed in the blanking process includes an upper edge 1, a lower edge 2, an outer edge 3, and an inner edge 4. The outer edge 3 is a curved segment with a rounded transition. The positioning hole 8 is located near the bend of the outer edge 3. The rounded transition of the outer edge 3 can alleviate stress concentration during the forming process and reduce the risk of edge cracking. The positioning hole 8 is located near the bend, which can utilize the area of ​​the blank with better rigidity as a positioning reference, reduce deformation of the positioning hole 8, and improve the positioning stability of the entire process.

[0043] In this invention, for ease of description, the figures in the specification are used as references. Figure 2 The distinction between the upper edge 1, lower edge 2, outer edge 3, and inner edge 4 based on the reference does not imply the actual orientation of the product during use.

[0044] In the stretching process, the blank is positioned using the positioning hole 8 to stretch and form the first boss 5, the second boss 6, and the third boss 7. The positioning hole 8 is located on the first boss 5. The third boss 7 is a semi-enclosed boss structure with one side open. The third boss 7 includes a planar top surface 71, a flanged pre-forming surface 73 that is raised relative to the blank, and a connecting curved surface 72 that connects the top surface 71 and the flanged pre-forming surface 73. The flanged pre-forming surface 73 is located in the flanged area at the tail of the control arm bracket. By designing the third boss 7 as a semi-enclosed boss structure with one side open, this invention retains the effective binding and guiding effect of the semi-enclosed structure on the material, ensuring the boss forming height and dimensional accuracy. At the same time, the one-sided open design eliminates the risk of material accumulation and tearing that is easily caused by a fully enclosed structure, achieving a balance between forming accuracy and material flowability. The flanging pre-forming surface 73 within the third boss 7 provides sufficient material extension for the tail flanging during the stretching stage. Combined with the guiding effect of the single-sided open structure, this ensures smoother and more uniform material flow during the flanging process, fundamentally solving the industry pain point of excessive material thinning and localized cracking in high flanging areas. Simultaneously, the top surface 71 and the flanging pre-forming surface 73 smoothly transition through the connecting curved surface 72, effectively dispersing concentrated stress during the forming process, avoiding the risk of sharp-corner cracks, and further improving the forming reliability and structural strength of the part. Placing the positioning hole 8 on the first boss 5, which has high structural rigidity and low deformation, significantly improves the stability and deformation resistance of the positioning datum throughout the entire process, effectively avoiding dimensional deviations caused by datum deformation.

[0045] In the first punching and trimming process, the upper edge 1 of the blank is trimmed, and a pre-punched hole 9 is punched at the second boss 6. Trimming the upper edge 1 removes irregular excess material caused by stretching, providing a regular foundation for subsequent flanging and side trimming. Punching at the second boss 6 utilizes a structurally stable area to form the pre-punched hole 9, resulting in higher hole position accuracy. The pre-punched hole 9 provides a foundation for subsequent hole enlargement, avoiding deformation and dimensional deviations caused by directly punching a large hole in one go.

[0046] Following the first punching and trimming process, the process includes flanging, a first side trimming, a second punching and trimming, a second side trimming, a third side trimming, punching, a first shaping, and a second shaping. Through these multiple processes, the blank is gradually formed into a control arm support part. This invention employs a step-by-step progressive forming method, applying deformation gradually to avoid excessive deformation in a single step, which could lead to cracking and springback. Multiple side trimming, punching, and shaping processes allow for layer-by-layer dimensional correction and stress elimination, improving part precision. The invention features a clear process logic and well-defined division of labor, facilitating mold design and automated production. The gradual formation of the blank into a part ensures strong process controllability and improves the overall finished product qualification rate.

[0047] In the flanging process, the blank is positioned using the positioning hole 8, the upper edge 1 of the blank is flanged upwards, and the outer edge 3 and inner edge 4 of the blank are flanged downwards. In the first side trimming process, the workpiece after flanging is positioned using the positioning hole 8, and the outer edge 3 and inner edge 4 after flanging are trimmed sideways. This invention, by using the single positioning hole 8 from the blanking stage as a unified positioning reference in the flanging process, ensures that the blank does not shift during multi-directional flanging, effectively guaranteeing the accuracy of flanging height, flanging angle, and the relative position between each flanging structure, significantly improving the dimensional consistency and assembly reliability of the product. Simultaneously, by performing flanging processing in different directions on the upper edge 1, outer edge 3, and inner edge 4 of the blank at the same time, a one-time forming of complex three-dimensional flanging structures is achieved, simplifying the process flow and improving processing efficiency. Immediately after the flanging process is completed, side trimming is performed to promptly remove irregular edges, excess material, and burrs generated during the flanging process. This not only makes the workpiece edge contour more regular and aesthetically pleasing, but also provides a stable and clean baseline for subsequent processing steps, further ensuring the stability of the overall processing quality.

[0048] In the second punching and trimming process, the workpiece is positioned using the positioning hole 8. The top surface 71 of the third boss 7 is removed, and the outer side 3 and inner side 4 after flanging are further trimmed. A side hole 10 is drilled in the inner side 4 after flanging. By continuing to use the unique positioning hole 8 for positioning in the second punching and trimming process, this invention ensures the accurate relative positional relationship between the independent features of top surface 71 removal, contour trimming, and side hole 10 processing, avoiding feature offset. Removing the top surface 71 of the third boss 7 effectively removes the process transition structure left during stretching and flanging, releases the forming internal stress accumulated in this area, and improves the internal structure of the workpiece. At the same time, further trimming of the outer side 3 and inner side 4 after flanging can optimize the external dimensions of the workpiece layer by layer, making the contour shape closer to the final product design requirements. The side holes 10 are machined on the already formed and structurally stable inner side edge 4. Relying on the stable flange structure established in the early stage as the processing basis, the positional accuracy and hole shape quality of the side holes 10 are effectively guaranteed, and the assembly performance of the final part is significantly improved.

[0049] In the second side trimming process, the workpiece is positioned using the positioning hole 8, and the outer portion of the connecting surface 72 between the third boss 7 and the top surface 71 is removed. In the third side trimming process, the workpiece is positioned using the positioning hole 8, and the inner portion of the connecting surface 72 between the third boss 7 and the top surface 71 is removed. At this point, the connecting surface 72 of the third boss 7 is completely removed. This invention employs a staged, step-by-step removal strategy for the connecting surface 72 of the third boss 7, first removing the outer portion of the connecting surface 72, then removing the inner portion. This step-by-step removal method effectively avoids severe vibration, displacement, or edge burrs caused by a single large cut, ensuring the stability and safety of the processing. Simultaneously, by continuously trimming different sides and transition surfaces of the workpiece layer by layer through three side trimming processes, refined processing of complex contours is achieved. This gradually eliminates processing errors, making the workpiece's external dimensions accurately approach the design requirements, ensuring the continuity, regularity, and dimensional consistency of the final part's contour, and significantly improving the part's appearance quality and structural accuracy.

[0050] In the punching process, the workpiece is positioned using the positioning hole 8, and a through hole 11 is machined on the workpiece surface. The mounting hole 12 is further enlarged around the original positioning hole 8 and the pre-punched hole 9. In this invention, the unique positioning hole 8 serves as a unified positioning reference during the punching process, ensuring the accurate positional relationship between the new through hole 11 and the existing hole system and overall structure. In particular, the method of enlarging the mounting hole 12 around the original positioning hole 8 and the pre-punched hole 9, compared to directly punching a large diameter hole, utilizes existing hole positions as guides, preventing the new hole position from shifting, becoming eccentric, or deforming during processing, significantly improving the positional accuracy of the mounting hole 12. Simultaneously, the enlarged hole processing method allows for more uniform hole wall cutting and a more regular hole shape, resulting in hole wall quality far superior to direct punching. This effectively ensures the fitting accuracy between the mounting hole 12 and the matching component, improving the final assembly reliability and performance of the parts.

[0051] The workpiece undergoes preliminary shaping to correct its outline, flange height, and flatness. In the second shaping process, the workpiece is finalized and calibrated to eliminate forming stress and ensure dimensional accuracy, resulting in a finished control arm bracket that meets the requirements. This invention employs a two-stage, step-by-step shaping process. The first shaping preliminarily corrects and adjusts the workpiece's outline, flange height, and flatness, significantly correcting accumulated dimensional deviations from previous processes and laying a solid dimensional foundation for final finishing. This effectively avoids rigid damage or flange collapse caused by excessive pressure during a single shaping process. The second shaping then performs final calibration, further correcting dimensional errors and effectively eliminating residual forming stress from previous processes, suppressing workpiece springback, and ensuring that the part's dimensions and geometric tolerances strictly conform to design standards. This results in a structurally stable and precision-compliant control arm bracket, significantly improving the dimensional stability and reliability of the part during vehicle use.

[0052] The rest of the contents of Example 2 are the same as those of Example 1.

[0053] The present invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of the embodiments above are only for the purpose of helping to understand the invention and its core ideas. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A molding process for an automotive control arm bracket, characterized in that, The process includes the following steps: blanking, stretching, and first punching and trimming; In the blanking process, the sheet metal is punched to form a blank, and a positioning hole is formed on the blank. The positioning hole serves as a common positioning reference for all subsequent processes. In the stretching process, the blank is positioned using the positioning holes, and the blank is stretched to form the basic outline of the control arm bracket. The tail area of ​​the control arm bracket is stretched to obtain the material extension in advance. In the first punching and trimming process, the stretched blank is trimmed and punched, and the punching forms a pre-punched hole.

2. The molding process of an automotive control arm bracket according to claim 1, characterized in that, The blank formed in the blanking process includes an upper edge, a lower edge, an outer edge, and an inner edge. The outer edge is a zigzag segment with a rounded transition. The positioning hole is located near the bend of the outer edge.

3. The molding process of an automotive control arm bracket according to claim 2, characterized in that, In the stretching process, the blank is positioned using the positioning hole and stretched to form a first boss, a second boss, and a third boss. The positioning hole is located on the first boss. The third boss is a semi-closed boss structure with one side open. The third boss includes a planar top surface, a flanged pre-forming surface that is raised relative to the blank, and a connecting curved surface that connects the top surface and the flanged pre-forming surface. The flanged pre-forming surface is located in the flanged area at the tail of the control arm bracket.

4. The molding process of an automotive control arm bracket according to claim 3, characterized in that, In the first punching and trimming process, the upper edge of the blank is trimmed, and a pre-punched hole is obtained by punching a hole at the second boss.

5. The molding process of an automotive control arm bracket according to claim 2, characterized in that, After the first punching and trimming process, the blank is further processed by flanging, first side trimming, second punching and trimming, second side trimming, third side trimming, punching, first shaping, and second shaping. After multiple processes, the blank is gradually formed into a control arm bracket part.

6. The molding process of an automotive control arm bracket according to claim 5, characterized in that, In the flanging process, the blank is positioned using the positioning holes, the upper edge of the blank is flanged upwards, and the outer and inner edges of the blank are flanged downwards. In the first side trimming process, the workpiece after flanging is positioned using the positioning hole, and the outer and inner sides of the flanged workpiece are trimmed.

7. The molding process of an automotive control arm bracket according to claim 5, characterized in that, In the second punching and trimming process, the workpiece is positioned using the positioning hole, the top surface of the third boss is cut off, the outer and inner edges after flanging are further trimmed, and a side hole is punched on the inner edge after flanging.

8. The molding process of an automotive control arm bracket according to claim 5, characterized in that, In the second side trimming process, the workpiece is positioned using the positioning hole, and the outer part of the curved surface connecting the third boss and the top surface is cut off. In the third side trimming process, the workpiece is positioned using the positioning hole, and the inner part of the connecting surface of the third boss and the top surface is cut off, so that the connecting surface of the third boss is completely cut off.

9. The molding process of an automotive control arm bracket according to claim 1, characterized in that, In the punching process, the workpiece is positioned using the positioning hole, a through hole is machined on the surface of the workpiece, and the original positioning hole and the pre-punched hole are further enlarged to form an installation hole.

10. The molding process of an automotive control arm bracket according to claim 1, characterized in that, In the first shaping process, the workpiece's outline, flange height, and flatness are initially shaped. In the second shaping process, the workpiece undergoes final finishing and calibration to eliminate forming stress and ensure dimensional accuracy, thereby obtaining a finished control arm bracket that meets the requirements.

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