Automobile mold pre-acceleration forming device applied to multi-order negative angle and using method thereof

Abstract

The application discloses a kind of applied to the automobile mould preacceleration forming device of multi-order negative angle and its using method, applied to the automobile mould preacceleration forming device of multi-order negative angle includes acceleration base, guide component, variable speed forming component, variable speed driving component and reset component;Guide component contains preacceleration guide plate and low-speed guide plate, can drive variable speed forming component to realize time-sequenced preacceleration lateral movement and low-speed precision forming movement, cooperate with the multi-order forming surface on variable speed forming component, realize the single-process one forming of multi-order negative angle.The present application solves the problem that the existing technology needs multi-process split, auxiliary power response is poor, small space small angle forming is easy to lock up and shake in multi-order negative angle forming, greatly improves forming efficiency and precision, reduces manufacturing cost, adapts to high-speed stamping mass production working condition.

Description

Technical Field

[0001] This invention relates to the field of automotive cold stamping die technology, and in particular to a pre-accelerated forming device and its method of use for cold stamping of automotive body panels with multiple negative angles. Background Technology

[0002] As the automotive industry moves towards a dual competition of quality and cost, vehicle body structures are constantly being upgraded towards streamlined, high-rigidity, and integrated designs. Multi-stage negative angle structures are widely used in key body panels such as side panels, door frames, fenders, and sill beams, and are a core design for improving vehicle body sealing performance, assembly precision, and appearance.

[0003] Multi-stage negative angle cover parts are typical complex structural components, requiring multi-step, small-angle lateral forming under high-speed, heavy-load, and confined space conditions. This places extremely high demands on the motion control, force conversion efficiency, and operational stability of the mold. Current automotive stamping production lines generally use high-speed presses ranging from 500 to 3500 tons, with a single stamping cycle of only about 0.5 seconds. Existing forming technologies struggle to accurately form multi-stage negative angles under such instantaneous conditions, exhibiting numerous insurmountable shortcomings:

[0004] First, conventional wedge mechanisms have low force conversion efficiency and slow response speed, making them unsuitable for the timing control requirements of multi-stage negative angle forming. Under high-speed and heavy-load conditions, they are prone to problems such as motion lag, uneven force distribution, and guide wear. In small-angle, short-stroke lateral forming, they are prone to seizing and vibration, failing to meet forming accuracy requirements. Second, pneumatic / hydraulic auxiliary mechanisms have poor response synchronization and large pressure fluctuations, making them prone to jamming and failure under high-speed stamping conditions. They also have high equipment maintenance costs and require additional power and control systems, making them unsuitable for the standardized operating procedures of existing stamping production lines. Third, while multi-process split forming schemes reduce the difficulty of single-stage forming, they significantly increase the number of molds, stamping processes, and manufacturing costs, extending the production cycle. At the same time, the cumulative errors of the processes will seriously reduce the forming accuracy of parts, failing to meet the high-quality, low-cost mass production requirements of automotive body panels.

[0005] Furthermore, as mold manufacturing moves towards green and lightweight designs, mold weight reduction and stroke reduction have become industry trends. However, reducing the mold closing height further compresses the available space for lateral molding, exacerbating the aforementioned molding defects. Ultimately, this necessitates increasing mold volume and adding molding processes, resulting in significant cost waste. In summary, the molding quality, production efficiency, and cost control of multi-stage negative angles have become key bottlenecks restricting the high-quality mass production of automotive body panels.

[0006] In particular, with the mass application of multi-stage negative angle covering parts, the industry's demand for mold forming devices adapted to high-speed, heavy-duty, small-space, and multi-stage linkage continues to grow. The market urgently needs a forming device that can achieve lateral motion pre-acceleration, efficient force conversion, and multi-time sequence coordinated control under low closing height and multi-stage negative angle conditions to solve problems such as incomplete forming, surface defects, mechanism jamming, and mold damage. This will meet the automotive manufacturing industry's needs for short-cycle, high-efficiency, low-cost, and high-consistency mass production, thereby improving the overall vehicle manufacturing quality and market competitiveness.

[0007] It should be noted that the analysis of the above technical information is the result of creative labor. The detailed description of it in the background section is only intended to deepen the understanding of the non-obviousness of the overall background of this application by those skilled in the art, and should not be regarded as an admission or in any form an implication that the above technical information constitutes prior art known to those skilled in the art. Summary of the Invention

[0008] To address the aforementioned deficiencies and technical biases in existing technologies, this technical solution proposes a pre-accelerated forming device for automotive molds with multi-stage negative angles and its usage method. The technical problem to be solved is that existing multi-stage negative angle automotive body panel forming technology cannot achieve single-process, unassisted, precise forming of multi-stage negative angles under high-speed stamping conditions with low closing height and small space. Furthermore, it suffers from defects such as easy seizing and vibration during forming, multiple processes, high cost, and poor precision.

[0009] The technical solution is as follows:

[0010] A pre-accelerated forming device for automotive molds with multi-stage negative angles includes an acceleration base, a guide assembly, a variable speed forming assembly, a variable speed drive assembly, and a reset assembly. The acceleration base is fixed to the lower mold body, the guide assembly is mounted on the acceleration base, the variable speed drive assembly is fixed to the upper mold, the variable speed forming assembly is slidably assembled within the variable speed drive assembly, and the reset assembly is located between the variable speed forming assembly and the variable speed drive assembly. The guide assembly includes a pre-acceleration guide plate and a low-speed guide plate. The pre-acceleration guide plate drives the variable speed forming assembly to generate lateral pre-acceleration motion, and the low-speed guide plate drives the variable speed forming assembly to generate low-speed lateral forming motion matching the multi-stage negative angle forming. The variable speed forming assembly has a pre-forming surface, a first-stage negative angle forming surface, and a second-stage negative angle forming surface arranged sequentially. Under the sequential action of the pre-acceleration guide plate and the low-speed guide plate, the variable speed forming assembly can drive the pre-forming surface, the first-stage negative angle forming surface, and the second-stage negative angle forming surface to sequentially complete the forming of the corresponding surfaces through time-sequential lateral motion.

[0011] The beneficial effects of this technical solution are as follows:

[0012] No additional pneumatic / hydraulic auxiliary power is required. The timing coordination of pre-acceleration and low-speed forming can be achieved solely through the mechanical movement of the mold going up and down. It is suitable for the instantaneous working conditions of high-speed stamping, with fast response speed and good synchronization, and no need to modify existing stamping equipment.

[0013] By pre-imposing a lateral initial velocity on the variable speed forming component through a pre-acceleration guide plate, and then cooperating with the precise guiding forming of the subsequent low-speed guide plate, the problems of locking, vibration, and jamming in lateral forming in small space, small angle, and short stroke are effectively solved, and the operational stability under high-speed and heavy-load conditions is greatly improved.

[0014] Integrating preforming, first-order negative angle, and second-order negative angle forming into a single process eliminates the need to separate multiple forming processes, significantly reducing the number of molds and stamping processes, lowering manufacturing costs, and avoiding cumulative process errors, thus significantly improving the forming accuracy of parts.

[0015] It can be adapted to lightweight molds with low closing height without increasing the mold volume, which is in line with the development trend of lightweight and green molds, and achieves dual savings in material cost and manufacturing cost.

[0016] Preferably, the guiding assembly further includes a balance guide plate, which is fixed on the acceleration base. The speed change drive assembly includes a speed change drive block, which has a balance surface that is slidably adapted to the balance guide plate. The balance guide plate and the balance surface cooperate to counteract the lateral force during the lateral forming process.

[0017] Beneficial effects: Through the sliding cooperation between the balance guide plate and the balance surface, the reverse lateral force generated during the lateral forming process is completely offset, avoiding the device from shifting or vibrating due to lateral force, further improving the stability of the device operation and the forming accuracy, and extending the service life of the mechanism.

[0018] Preferably, the variable speed forming component includes a variable speed forming block, and the pre-forming surface, the first-order negative angle forming surface, and the second-order negative angle forming surface are all disposed at the forming end of the variable speed forming block; the variable speed forming block is provided with a pre-acceleration force-bearing surface, a high-speed sliding surface, and a low-speed sliding surface, the pre-acceleration force-bearing surface is matched with the inclination angle of the pre-acceleration guide plate, the high-speed sliding surface is slidably adapted to the pre-acceleration guide plate, and the low-speed sliding surface is slidably adapted to the low-speed guide plate.

[0019] Further beneficial effects include: through precise matching of multiple mating surfaces, smooth switching between pre-accelerated motion and low-speed molding motion is achieved, ensuring precise control of motion trajectory and molding sequence, while further enhancing the anti-locking and anti-jamming effects.

[0020] Preferably, the tilt angle of the pre-acceleration guide plate matches the first-order negative angle of the part to be formed, and the tilt angle of the low-speed guide plate is consistent with the second-order negative angle of the part to be formed; the vertical height of the pre-acceleration guide plate along the mold closing direction is not less than 4 times the sum of the first-order negative angle height and the second-order negative angle height.

[0021] Further beneficial effects include: by matching the guide plate angle and the negative angle, the forming motion is precisely matched with the part surface. At the same time, by limiting the height of the pre-acceleration guide plate, sufficient pre-acceleration stroke is ensured, providing enough lateral initial velocity for the variable speed forming block, thus completely solving the problem of locking up in small angle forming.

[0022] Preferably, the variable speed drive assembly includes a variable speed drive block, a limiting slider, and a pre-push slider; the variable speed drive block has symmetrical movable surfaces inside, and movable guide plates are fixed on both sides of the variable speed forming assembly, and the variable speed forming assembly slides with the movable surfaces through the movable guide plates; the limiting slider is fixed on the variable speed drive block to limit the sliding stroke of the variable speed forming assembly; the pre-push slider is fixed on the variable speed drive block and slides with the pre-push surface of the variable speed forming assembly.

[0023] Further beneficial effects include: improved sliding wear resistance through the movable guide plate, while facilitating adjustment of the sliding gap and ensuring smooth sliding; prevention of the variable speed forming component from detaching through the limiting slider, thus improving the safety of device operation; and further improvement of sliding smoothness through the pre-pushing slider, while providing a convenient means for adjusting the forming gap.

[0024] Preferably, the reset assembly includes a reset spring, the speed-changing forming assembly has a reset spring mounting surface, the speed-changing drive assembly has a reset spring limiting surface, and the two ends of the reset spring respectively abut against the reset spring mounting surface and the reset spring limiting surface.

[0025] Further beneficial effects include: the return spring enables energy storage during mold closing and energy release during mold opening, ensuring accurate reset of the variable speed forming component after mold opening, adapting to the continuous operation requirements of high-speed stamping, with a simple and reliable structure and low maintenance costs.

[0026] A method for using a pre-accelerated forming device for automotive molds with multi-stage negative angles includes the following steps: S1 Process pretreatment and layout: Based on the surface characteristics of the multi-stage negative angle region of the part to be formed, set up the pre-processing process; S2 Device parameter configuration: Based on the multi-stage negative angle parameters of the part to be formed, configure the angle and height parameters of the pre-acceleration guide plate and the low-speed guide plate, as well as the parameters of each forming surface on the variable speed forming assembly; S3 Device assembly: Fix the acceleration base to the lower mold, install the guide assembly on the acceleration base, and fix the variable speed drive assembly. On the upper mold, the variable speed forming component, with the reset component assembled, is slidably assembled into the variable speed drive component, completing the overall assembly of the device; S4 Stamping Forming: Control the upper and lower molds to close, and drive the variable speed forming component to complete the pre-accelerated lateral movement and low-speed lateral forming movement in sequence through the guide component, so that each forming surface can complete the pre-forming, first-order negative angle forming and second-order negative angle forming in sequence, realizing the single-process one-time forming of multiple negative angles; S5 Mold Opening Return: The mold opens and moves upward, and the variable speed forming component is reset under the action of the reset component, completing a single stamping cycle.

[0027] The core beneficial effects of this plan are:

[0028] By using targeted pretreatment in the preceding process, the part surface is effectively solidified, reducing defects such as springback, twisting, and stress deformation in the multi-stage negative angle forming process, thus improving the forming quality from the source.

[0029] Through standardized parameter configuration methods, it is possible to quickly adapt to the multi-stage negative angle molding requirements of different specifications and shapes, ensuring molding accuracy and batch stability.

[0030] The entire process requires no additional auxiliary power control; multi-stage negative angle forming can be completed solely through the timing coordination of the mechanical structure. It is easy to operate, adapts to the standardized operating procedures of existing high-speed stamping production lines, and has strong potential for widespread adoption.

[0031] The accompanying parameter adjustment and repair methods can effectively solve common problems such as springback and surface defects in cold stamping, greatly reduce the difficulty of adjustment for craftsmen, shorten the mold debugging cycle, and improve production efficiency.

[0032] Preferably, in step S1, if the multi-stage negative angle surface of the part to be formed is a curved shape and the preceding process only involves drawing and trimming, then a pre-bending shape is set in the drawing process. The drawing depth of the pre-bending is 30%-50% of the bending height of the first-stage negative angle, and the fillet of the pre-bending point overlapping the plane is enlarged by R1-R2 compared to the actual required fillet. If the multi-stage negative angle surface of the part to be formed is a straight line and a flanging process can be set in the preceding process, then a flanging process is set after drawing and before the multi-stage negative angle is formed, and the flanging angle is 90 degrees.

[0033] Beneficial effects: Different pre-treatment schemes are adopted for different surface features to solidify the surface of the part in a targeted manner, disperse the molding stress, and avoid springback, twisting and surface deformation during the molding process from the source, thereby improving the molding quality.

[0034] Preferably, in step S2, the parameter configuration of each forming surface is as follows: the angle of the pre-forming surface is 90 degrees, and its height is set to 0.8-2 times the sum of the length of the first-order negative angle and the length of the second-order negative angle according to the previous pre-processing; the width of the first-order negative angle forming surface is consistent with the width of the first-order negative angle of the part, and has been formed, with the cutting angle increased by 0.8-1.2 degrees; the width of the second-order negative angle forming surface is not less than 0.7 times the width of the second-order profile of the part, and has been formed, with the cutting angle increased by 1-2 degrees; the rounded corner of the second-order negative angle is sharpened, and the rounded corner is reduced by R0.7-R1 compared to the designed rounded corner.

[0035] Further beneficial effects include: ensuring preforming effect through parameter adaptation of the preformed surface; accurately offsetting material springback through overforming and rounded corner sharpening, further improving the forming accuracy of multi-stage negative angles, and solving problems such as incomplete forming and surface defects.

[0036] Preferably, the process also includes step S6, adjustment and optimization: by adjusting the thickness of the low-speed guide plate, the pre-acceleration guide plate, and the pre-push slider, the forming gap of the variable speed forming assembly is adjusted, and the forming size and surface defects of the parts are corrected.

[0037] Further benefits include: without disassembling the mold body, the molding accuracy can be adjusted simply by adjusting the thickness of the guide plate and the slider, which greatly reduces the difficulty and workload of mold debugging, shortens the debugging cycle, and improves production efficiency.

[0038] In summary, compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] By using pre-acceleration, the problem of single-process sequential molding with multiple negative angles is solved, simplifying the molding process that requires additional processes or auxiliary facilities into a single-process convenient molding process. Furthermore, the molding quality is guaranteed through experimental parameter settings, resulting in a significant improvement in quality and efficiency.

[0040] Pre-acceleration and time-sequential differential motion provide solutions for preventing seizures and vibrations in small-space, small-angle lateral forming. These solutions can be widely applied to lateral forming and other applications, making them high-quality solutions for high-speed, small-angle problems.

[0041] Integrating multiple processes, it provides a low-cost molding solution for multi-stage negative angle automotive parts, offering a positive contribution to improving vehicle quality without increasing costs.

[0042] Significantly improved molding efficiency: The multi-stage negative angle molding process that requires 2-3 steps in the existing technology is integrated into a single process that can be completed in one go. The entire surface can be formed in a single stamping cycle. It is compatible with the working conditions of existing 500-3500 ton high-speed presses with a single stamping time of 0.5 seconds, and the production efficiency is increased by more than 60%.

[0043] Significantly optimized molding quality: Through the combination of pre-acceleration timing control, over-molding parameter compensation, and pre-processing of previous steps, problems such as springback, twisting, surface defects, and incomplete molding in multi-stage negative angle molding are effectively solved, the dimensional accuracy of parts is improved by more than 40%, and the defect rate is greatly reduced.

[0044] High operational stability and reliability: By presetting the initial acceleration speed, the problems of locking and vibration in small-angle, short-stroke lateral forming are solved. Combined with the lateral force cancellation structure of the balance guide plate, there are no problems such as motion lag, uneven force, and guide wear under high speed and heavy load, and the service life of the mechanism is increased by more than 50%.

[0045] Manufacturing costs are significantly reduced: no additional pneumatic / hydraulic auxiliary power system is required, no multiple sets of molds and multiple processes are needed, the mold closing height can be reduced by 20%-30%, the mold material and manufacturing costs are reduced by more than 30%, and equipment maintenance costs and production energy consumption are reduced, which is in line with the trend of green manufacturing development.

[0046] It has strong adaptability and versatility: it can be used not only for molding multi-stage negative angle automotive body panels, but also for various small-angle and short-stroke lateral molding conditions by changing the molding working surface on the variable speed molding block. It has a wide range of applications and high promotion value. Attached Figure Description

[0047] To more clearly illustrate the embodiments of this technical solution, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this technical solution. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 This is an exploded structural diagram of the pre-accelerated forming device described in this invention;

[0049] Figure 2 This is a schematic diagram of the intermediate cross-sectional structure of the pre-accelerated forming device described in this invention;

[0050] Figure 3 This is a schematic diagram of the structure of the acceleration base component described in this invention;

[0051] Figure 4 This is a front structural diagram of the variable speed forming block component described in this invention;

[0052] Figure 5 This is a schematic diagram of the bottom structure of the variable speed forming block component described in this invention;

[0053] Figure 6 This is a schematic diagram of the structure of the speed-changing drive block component described in this invention;

[0054] Figure 7 This is a schematic diagram of the application status of the present invention. Figure 1 Initial contact stage;

[0055] Figure 8 This is a schematic diagram of the application status of the present invention. Figure 2 The final state;

[0056] Figure 9 This is an exploded view of the present invention;

[0057] Figure 10 This is a cross-sectional view of the first-order negative angle forming stage of the present invention;

[0058] Figure 11 This is a cross-sectional view of the first stage of the second-order negative angle forming of the present invention.

[0059] Explanation of the corresponding labels in the attached diagram:

[0060] 1-Acceleration base; 2-Low speed guide plate; 3-Pre-acceleration guide plate;

[0061] 4-Variable speed forming block; 4.1-Pre-acceleration force-bearing surface; 4.2-Reset spring mounting surface; 4.3-Pre-push surface; 4.4-Pre-forming surface; 4.5-First-order negative angle forming surface; 4.6-Second-order negative angle forming surface; 4.7-Low-speed sliding surface; 4.8-High-speed sliding surface;

[0062] 5-Modible guide plate; 6-Reset spring;

[0063] 7-Transmission drive block; 7.1-Balance surface; 7.2-Pre-acceleration push surface; 7.3-Moving surface; 7.4-Reset spring limit surface;

[0064] 8-Limit slider; 9-Pre-push slider; 10-Balance guide plate; 11-Partial part. Detailed Implementation

[0065] The technical solutions of this technical solution will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this technical solution. Obviously, the described embodiments are only some embodiments of this technical solution, and not all embodiments. Based on the core concept of this technical solution and the following embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this technical solution.

[0066] like Figures 1 to 6As shown, to facilitate a clear understanding of the technical solution of this invention, the technical terms and corresponding reference numerals involved in this specification will be explained in a unified manner:

[0067] Acceleration base 1: This is the bottom support component of the device, used to fix it to the lower mold body and provide an installation reference for the other components;

[0068] Low-speed guide plate 2: Used to convert the vertical mold closing motion of the mold into a low-speed lateral forming motion, providing precise guidance for second-order negative angle forming;

[0069] Pre-acceleration guide plate 3: used to convert the vertical mold closing motion of the mold into lateral pre-acceleration motion, and to pre-set the lateral initial velocity for the molding component;

[0070] Variable speed forming block 4: This is the core forming execution component of the device, used to support the forming working surface, and completes the forming of multi-stage negative angle structures through timed lateral motion;

[0071] Pre-acceleration force-bearing surface 4.1: Located on the upper part of the variable speed forming block 4, used to receive the pre-acceleration driving force;

[0072] Reset spring mounting surface 4.2: Located at the tail of the speed-changing forming block 4, used for mounting the reset component;

[0073] Pre-push surface 4.3: Located on the upper part of the variable speed forming block 4, used to receive the pre-push driving force;

[0074] Preforming surface 4.4: Located at the forming end of the variable speed forming block 4, used to complete the preforming process of the part;

[0075] First-order negative angle forming surface 4.5: Located at the forming end of the variable speed forming block 4, used to complete the forming of the first-order negative angle structure of the part;

[0076] Second-order negative angle forming surface 4.6: Located at the forming end of the variable speed forming block 4, used to complete the forming of the second-order negative angle structure of the part;

[0077] Low-speed sliding surface 4.7: Located on the bottom surface of variable speed forming block 4, used to cooperate with low-speed guide plate 2 to realize low-speed lateral forming motion;

[0078] High-speed sliding surface 4.8: Located on the bottom surface of the variable speed forming block 4, used to cooperate with the pre-acceleration guide plate 3 to achieve lateral pre-acceleration motion;

[0079] Movable guide plate 5: Fixed on both sides of the variable speed forming block 4, used to improve the wear resistance of the sliding fit and facilitate the adjustment of the sliding clearance;

[0080] Return spring 6: This is the reset component of the device, used to drive the molding component to reset during the mold opening process;

[0081] Speed-changing drive block 7: This is the drive component of the device, fixed to the upper mold, used to move synchronously with the upper mold and drive the forming component to complete the preset action;

[0082] Balance surface 7.1: Located on the side of the transmission drive block 7, used to counteract the reverse force during the lateral forming process;

[0083] Pre-acceleration driving surface 7.2: Located inside the transmission drive block 7, used to cooperate with the pre-acceleration guide plate 3 to transmit the pre-acceleration driving force;

[0084] Movable surface 7.3: Located inside the speed change drive block 7, it is a left-right symmetrical sliding groove structure used to provide sliding guidance for the forming component;

[0085] Reset spring limit surface 7.4: Located inside the transmission drive block 7, it is used to provide installation limit for the reset component;

[0086] Limiting slider 8: Fixed to the lower end of the speed change drive block 7, used to limit the sliding stroke of the forming component and prevent it from coming off;

[0087] Pre-push slider 9: Fixed inside the speed drive block 7, used to improve the smoothness of the sliding of the forming component and facilitate the adjustment of the forming gap;

[0088] Balance guide plate 10: fixed on the acceleration base 1, used to cooperate with the balance surface 7.1 to counteract lateral forces and ensure the stability of the device operation;

[0089] Part 11: The target forming area for the multi-stage negative angle automotive body panel to be formed.

[0090] Example 1

[0091] This embodiment provides a pre-accelerated forming device for automotive molds with multiple negative angles, including an acceleration base 1, a guide assembly, a speed-changing forming assembly, a speed-changing drive assembly, and a reset assembly.

[0092] The acceleration base 1 is an integrated plate-type load-bearing structure, fixedly installed in the preset mounting position of the lower mold body by fasteners, providing a stable installation reference for the entire device. The guide assembly includes a pre-acceleration guide plate 3 and a low-speed guide plate 2, both of which are fixedly installed on the upper surface of the acceleration base 1 by fasteners. They are arranged sequentially along the mold closing direction, with the pre-acceleration guide plate 3 located upstream of the mold closing stroke and the low-speed guide plate 2 located downstream of the mold closing stroke. The speed-changing drive assembly is fixedly installed on the upper mold by fasteners and can synchronously complete the vertical mold opening and closing movement with the upper mold. The speed-changing forming assembly is slidably assembled in the internal cavity of the speed-changing drive assembly and can reciprocate along the side perpendicular to the mold closing direction. The reset assembly is located between the speed-changing forming assembly and the speed-changing drive assembly to provide the driving force for the speed-changing forming assembly to reset after mold opening.

[0093] The forming end of the variable speed forming component is provided with a pre-forming surface 4.4, a first-order negative angle forming surface 4.5, and a second-order negative angle forming surface 4.6 arranged in sequence. The profile of the three forming working surfaces corresponds to and matches the design profile of the pre-forming area, the first-order negative angle area, and the second-order negative angle area of ​​the part to be formed.

[0094] The working process of this embodiment is as follows:

[0095] When the mold closes, the upper mold drives the variable speed drive assembly to descend vertically. The variable speed forming assembly first contacts and engages with the pre-acceleration guide plate 3. The inclined guide surface of the pre-acceleration guide plate 3 converts the vertical downward motion of the mold into the lateral pre-acceleration motion of the variable speed forming assembly, pre-setting the lateral initial velocity for the variable speed forming assembly. At the same time, the pre-forming surface 4.4 on the variable speed forming assembly contacts the part to be formed, completing the forming of the pre-forming area of ​​the part. As the upper mold continues to descend, the variable speed forming assembly contacts and engages with the low-speed guide plate 2. The inclined guide surface of the low-speed guide plate 2 drives the variable speed forming assembly to perform low-speed precise lateral movement in the direction matching the second-order negative angle forming, sequentially driving the first-order negative angle forming surface 4.5 to complete the forming of the first-order negative angle structure of the part, and the second-order negative angle forming surface 4.6 to complete the forming of the second-order negative angle structure of the part, finally realizing the single-process one-time forming of multi-order negative angle structures.

[0096] When the mold opens, the upper mold drives the speed-changing drive assembly to move vertically upward, and the speed-changing forming assembly slides laterally in the opposite direction under the drive of the reset assembly, returning to the initial position and completing a single stamping cycle.

[0097] Example 2

[0098] This embodiment is based on Embodiment 1, and the guide component is optimized and improved.

[0099] The guide assembly also includes a balance guide plate 10, which is fixedly installed on the upper surface of the acceleration base 1 by fasteners and is arranged in parallel with the pre-acceleration guide plate 3 and the low-speed guide plate 2; the speed change drive assembly includes a speed change drive block 7, and the side of the speed change drive block 7 is provided with a balance surface 7.1 that is slidably adapted to the balance guide plate 10.

[0100] Throughout the entire mold closing and forming process, the balance guide plate 10 always slides and fits against the balance surface 7.1, which can completely offset the reverse force generated by the lateral forming force applied to the part by the variable speed forming component during the lateral forming process. This prevents the device from shifting or vibrating due to lateral force, greatly improving the stability and forming accuracy of the device operation. At the same time, it can reduce the wear of the guide structure and extend the service life of the device.

[0101] Example 3

[0102] This embodiment optimizes and improves the variable speed forming component and the guiding component based on embodiment 1 or embodiment 2.

[0103] The variable speed forming component includes a variable speed forming block 4. A pre-forming surface 4.4, a first-order negative angle forming surface 4.5, and a second-order negative angle forming surface 4.6 are all integrally machined onto the forming end of the variable speed forming block 4. A pre-acceleration force-bearing surface 4.1 is machined on the upper side of the variable speed forming block 4, and a high-speed sliding surface 4.8 and a low-speed sliding surface 4.7 are sequentially arranged along the mold closing direction on the bottom surface. The inclination angle of the pre-acceleration force-bearing surface 4.1 is consistent with the inclination angle of the pre-acceleration guide plate 3. The high-speed sliding surface 4.8 is slidably adapted to the upper surface of the pre-acceleration guide plate 3, and the low-speed sliding surface 4.7 is slidably adapted to the upper surface of the low-speed guide plate 2.

[0104] During mold closing, the high-speed sliding surface 4.8 first contacts the pre-acceleration guide plate 3. The inclined guide surface of the pre-acceleration guide plate 3 converts the vertical downward motion of the mold into the lateral pre-acceleration motion of the variable speed forming block 4, enabling the variable speed forming block 4 to obtain a stable lateral initial velocity. As the upper mold continues to descend, the low-speed sliding surface 4.7 contacts the low-speed guide plate 2. The inclined guide surface of the low-speed guide plate 2 drives the variable speed forming block 4 to move along a preset low-speed lateral trajectory, completing precise multi-stage negative angle forming. By pre-setting the lateral initial velocity through pre-acceleration motion, the problems of locking, jamming, and vibration that are prone to occur in small-angle, small-stroke lateral motion can be effectively avoided, ensuring smooth motion under high-speed stamping conditions.

[0105] Furthermore, the tilt angle of the pre-acceleration guide plate 3 matches the first-order negative angle of the part to be formed. Specifically, when the first-order negative angle is an integer multiple of 5, the tilt angle of the pre-acceleration guide plate 3 is consistent with the first-order negative angle; when the first-order negative angle is not an integer multiple of 5, the tilt angle of the pre-acceleration guide plate 3 is rounded to the nearest integer multiple of 5. The tilt angle of the low-speed guide plate 2 is completely consistent with the second-order negative angle of the part to be formed, ensuring the accuracy of the second-order negative angle forming. The vertical height H of the pre-acceleration guide plate 3 along the mold closing direction is not less than 4 times the sum of the first-order negative angle height and the second-order negative angle height, ensuring sufficient pre-acceleration stroke and providing sufficient pre-acceleration distance for the variable speed forming block 4 to obtain a stable lateral initial velocity.

[0106] As an exemplary parameter of this embodiment, when the first negative angle of the part to be formed is 12°, the first negative angle height is 5mm, the second negative angle is 8°, and the second negative angle height is 3mm, the tilt angle of the pre-acceleration guide plate 3 is rounded to 10°, and the vertical height H ≥ (5+3)×4=32mm. In this embodiment, H=35mm is taken; the tilt angle of the low-speed guide plate 2 is 8°, which is consistent with the second negative angle.

[0107] Example 4

[0108] This embodiment optimizes and improves the variable speed drive component based on embodiment 1.

[0109] The transmission drive assembly includes a transmission drive block 7, a limit slider 8, and a pre-push slider 9. The transmission drive block 7 has internally machined symmetrical movable surfaces 7.3, which are sliding groove structures extending laterally. Movable guide plates 5 are fixed to both sides of the transmission forming block 4 by fasteners. The transmission forming block 4 slides with the movable surfaces 7.3 through the movable guide plates 5. The movable guide plates 5 are made of wear-resistant alloy material, which can significantly improve the wear resistance of the sliding fit. At the same time, the sliding gap between the transmission forming block 4 and the movable surfaces 7.3 can be adjusted by replacing the movable guide plates 5 with different thicknesses to ensure smooth sliding.

[0110] The limiting slider 8 is detachably fixed to the lower end of the transmission drive block 7. Part of the limiting slider 8 extends below the movable surface 7.3 to limit the downward limit position of the transmission forming block 4 and prevent the transmission forming block 4 from coming out of the transmission drive block 7. The pre-push slider 9 is detachably fixed to the inside of the transmission drive block 7. The working surface of the pre-push slider 9 slides and adapts to the pre-push surface 4.3 of the transmission forming block 4. The pre-push slider 9 is made of wear-resistant alloy material, which can improve the smoothness of the sliding of the transmission forming block 4. At the same time, the initial position and forming gap of the transmission forming block 4 can be adjusted by adjusting the thickness of the pre-push slider 9, which facilitates on-site adjustment of forming accuracy.

[0111] Example 5

[0112] This embodiment is based on Embodiment 1, and the reset component is optimized and improved.

[0113] The reset assembly includes at least one set of reset springs 6. The tail of the transmission forming block 4 is machined with a reset spring mounting surface 4.2. The interior of the transmission drive block 7 is machined with a reset spring limiting surface 7.4 that is opposite to the reset spring mounting surface 4.2. The two ends of the reset spring 6 abut against the reset spring mounting surface 4.2 and the reset spring limiting surface 7.4, respectively.

[0114] During mold closing, the variable speed forming block 4 slides forward laterally, compressing the return spring 6 and allowing it to store elastic energy. During mold opening, the return spring 6 releases its elastic potential energy, driving the variable speed forming block 4 to slide backward laterally back to its initial position, preparing for the next stamping cycle. In this embodiment, the return spring 6 is a rectangular cross-section mold-specific nitrogen spring, which can provide a stable and continuous return force, suitable for continuous high-speed stamping operations.

[0115] Example 6

[0116] This embodiment provides a generalized alternative implementation of the present invention.

[0117] When the device is only used for anti-lock and anti-vibration scenarios of small-angle, short-stroke lateral forming, the pre-forming surface 4.4, the first-order negative angle forming surface 4.5, and the second-order negative angle forming surface 4.6 on the variable speed forming block 4 can be replaced with a universal mounting surface. The universal mounting surface can adopt a vertical or inclined surface structure to install a special forming block corresponding to the forming requirements, thereby realizing the anti-lock and anti-vibration functions of various small-angle, short-stroke lateral forming, greatly improving the versatility and applicability of the device.

[0118] Example 7

[0119] This embodiment provides a pre-accelerated forming device for automotive molds with multi-stage negative angles that can be directly applied to mass production, and its usage method, fully covering all the optimized technical solutions of this invention, as detailed below:

[0120] I. Complete Structure and Assembly Process of the Device

[0121] The pre-accelerated molding device of this embodiment includes an acceleration base 1, a low-speed guide plate 2, a pre-accelerated guide plate 3, a variable-speed molding block 4, a movable guide plate 5, a reset spring 6, a variable-speed drive block 7, a limit slider 8, a pre-push slider 9, and a balance guide plate 10.

[0122] The complete assembly process is as follows:

[0123] Accelerator base assembly: The acceleration base 1 is fixed to the preset mounting position on the lower mold body using hex socket screws. The low-speed guide plate 2, pre-acceleration guide plate 3, and balance guide plate 10 are respectively fixed and installed in the corresponding mounting slots on the upper surface of the acceleration base 1 using hex socket screws, thus completing the assembly of the acceleration base components. Among them, the pre-acceleration guide plate 3 is located upstream in the mold closing direction, the low-speed guide plate 2 is located downstream in the mold closing direction, and the balance guide plate 10 is located on the side of the acceleration base 1, arranged parallel to the pre-acceleration guide plate 3.

[0124] Assembly of the variable speed forming block component: According to the design parameters of the part to be formed, the pre-forming surface 4.4, the first-order negative angle forming surface 4.5, and the second-order negative angle forming surface 4.6 on the variable speed forming block 4 are precision machined; two sets of movable guide plates 5 are fixedly installed on the left and right sides of the variable speed forming block 4 with hexagonal screws; two sets of return springs 6 are installed on the return spring mounting surface 4.2 at the tail of the variable speed forming block 4 to complete the assembly of the variable speed forming block component.

[0125] Gearbox drive block component and overall assembly: The gearbox drive block 7 is fixedly installed on the corresponding mounting position of the upper mold using hexagon socket screws; the pre-push slider 9 is fixedly installed on the corresponding mounting position inside the gearbox drive block 7 using hexagon socket screws; the assembled gearbox forming block component is placed into the symmetrical movable surfaces 7.3 inside the gearbox drive block 7, so that the movable guide plate 5 slides and fits against the movable surface 7.3, the pre-acceleration force-bearing surface 4.1 fits against the pre-acceleration pushing surface 7.2 of the gearbox drive block 7, and the pre-push surface 4.3 fits against the pre-push slider 9; two sets of limiting sliders 8 are fixedly installed on the lower left and right sides of the gearbox drive block 7 using hexagon socket screws, locking the gearbox forming block component into the interior of the gearbox drive block 7, limiting its sliding stroke, and completing the assembly of the overall device.

[0126] II. Basic parameters of the part to be formed

[0127] In this embodiment, the part to be formed is the inner panel of the car door sill beam. The design parameters of its multi-stage negative angle area are: the first-stage negative angle is 10°, the first-stage negative angle is 6mm, the second-stage negative angle is 7°, the second-stage negative angle is 4mm, the part material is DC06 cold-rolled steel plate, the material thickness is 0.8mm, and the multi-stage negative angle surface is an inner arc curved surface.

[0128] III. Molding Process and Equipment Parameter Configuration

[0129] Pre-processing of preceding steps:

[0130] In this embodiment, the multi-stage negative angle surface is an inner arc surface. The preceding processes only include drawing and trimming. Therefore, a pre-bending shape is set in the drawing process. The pre-bending position is set at the intersection of the planar surface and the first-stage bend. The drawing depth of the pre-bending is 40% of the height of the first-stage negative angle bend, i.e., 2.4mm. The fillet of the pre-bending position where it overlaps with the planar surface is designed to have a fillet radius of R3. Therefore, R1 is enlarged and processed into R4 to reserve space for strong pressure bending in the subsequent negative angle forming, solidify the planar surface, and avoid the overall deformation of the part caused by the subsequent forming stress.

[0131] Device core parameter configuration:

[0132] (1) Parameters of pre-acceleration guide plate 3: The first-order negative angle of 10° is an integer multiple of 5, so the tilt angle between the pre-acceleration guide plate 3 and the pre-acceleration force surface 4.1 is set to 10°; the vertical height H of the pre-acceleration guide plate 3 is set to 45mm, which meets the requirement of not less than 4 times the sum of the first-order and second-order negative angle heights.

[0133] (2) Low-speed guide plate 2 parameters: The tilt angle of the low-speed guide plate 2 is consistent with the second negative angle, and is set to 7°.

[0134] (3) Rounding of second-order negative angle: The design rounding of the second-order negative angle is R4. Therefore, it is sharpened to reduce R0.7 and processed to R3.3 to reduce the impact of springback and improve the molding stability.

[0135] (4) Preformed surface 4.4 parameters: The angle of the preformed surface 4.4 is set to 90° vertically; a pre-bending preform is set in the previous step, so the height of the preformed surface 4.4 is set to 25.2mm, which is 1.8 times the sum of the first negative angle length and the second negative angle length.

[0136] (5) First-order negative angle forming surface 4.5 parameters: The width of the forming surface is consistent with the design width of the first-order negative angle of the part, which is 12mm; after forming treatment, the cutting angle is increased by 1.0°, that is, the forming surface angle is set to 11° to counteract material springback.

[0137] (6) Second-order negative angle forming surface 4.6 parameters: The forming surface width is set to 8mm, which is 0.8 times the width of the second-order surface of the part; after forming treatment, the cutting angle is increased by 1.5°, that is, the forming surface angle is set to 8.5° to counteract material springback.

[0138] IV. Complete Stamping Process

[0139] Molding preparation stage: The upper mold moves upward, driving the speed drive block 7 and the speed forming block 4 to move upward synchronously. Under the action of the spring force of the return spring 6 and gravity, the speed forming block 4 stops at the initial position below the speed drive block 7, forming an open cavity between the upper and lower molds. The part to be formed is placed into the mold cavity for positioning, completing the molding preparation.

[0140] Pre-forming stage: As the upper mold moves downward, the balance guide plate 10 first contacts and adheres to the balance surface 7.1 of the speed drive block 7, limiting the vertical movement of the device and counteracting the lateral force in the subsequent forming process; at the same time, the pre-forming surface 4.4 of the speed forming block 4 contacts the part part 11, completing the forming of the pre-forming area and the rounded corners, and solidifying the part surface.

[0141] Pre-acceleration and first-order negative angle forming stage: The upper mold continues to descend, and the high-speed sliding surface 4.8 of the bottom surface of the variable speed forming block 4 contacts the pre-acceleration guide plate 3. Under the downward pressure of the variable speed drive block 7 and the inclined guiding action of the pre-acceleration guide plate 3, the variable speed forming block 4 generates a pre-acceleration motion in the lateral direction to obtain a stable lateral initial velocity. At the same time, the first-order negative angle forming surface 4.5 contacts the first-order negative angle area of ​​the part, completing the forming of the first-order negative angle structure. During this process, the balance guide plate 10 continues to be in contact with the balance surface 7.1 to counteract the lateral force; the pre-acceleration force-bearing surface 4.1 and the pre-acceleration pushing surface 7.2 perform symmetrical compensating lateral movements to avoid the vibration and positioning deviation problems caused by unidirectional movement, ensuring smooth forming.

[0142] Low-speed forming and second-order negative angle forming stages: After the first-order negative angle forming is completed, the upper mold continues to descend. The low-speed sliding surface 4.7 on the bottom of the variable-speed forming block 4 contacts the low-speed guide plate 2. The inclined surface of the low-speed guide plate 2 drives the variable-speed forming block 4 to perform low-speed precise lateral movement along the direction matching the second-order negative angle. The second-order negative angle forming surface 4.6 contacts the second-order negative angle area of ​​the part, completing the forming of the second-order negative angle structure. During this process, the pre-acceleration guide plate 3 still cooperates with the high-speed sliding surface 4.8 to provide auxiliary driving force for small-angle forming. Through the dual assistance of pre-acceleration compensation and auxiliary driving, problems such as locking, vibration, and uneven speed in small-stroke, small-space, and small-angle forming are completely eliminated. With the preset over-forming parameters, high-quality multi-order negative angle precise forming is completed.

[0143] Mold opening and return stage: After molding is completed, the upper mold moves upward, driving the speed drive block 7 to move upward synchronously. Under the elastic force of the return spring 6, the speed forming block 4 slides back to the initial position in the opposite direction. The balance guide plate 10 disengages from the balance surface 7.1, the mold is fully opened, the molded part is taken out, and a single stamping cycle is completed.

[0144] V. On-site adjustment and optimization methods

[0145] When parts have dimensional deviations, surface defects, or work hardening problems, there is no need to disassemble the mold body. Simply by replacing the low-speed guide plate 2, pre-acceleration guide plate 3, and pre-push slider 9 of different thicknesses, the movement trajectory and forming gap of the variable speed forming block 4 can be adjusted, forming defects can be quickly corrected, greatly reducing the difficulty and workload of on-site adjustment and shortening the mold debugging cycle.

[0146] Preferred Implementation

[0147] Through group-based batch experiments, the forming process of automotive body panels (hereinafter referred to as parts) with multi-stage negative angle structures was decomposed and time-sequenced. Assisted acceleration tests and motion trajectory balancing were implemented. Quality problems such as springback, deformation, and torsion during the manufacturing process were eliminated through elimination tests. Pre-acceleration and bidirectional propulsion structures were adopted to address the problem of low stroke in small spaces. A balancing structure was used to balance lateral forces to maintain the continuity and stability of high-speed heavy-load operations. A variable-track motion forming block, combined with a retraction forming method, was used for the forward forming of multi-stage negative angles. This solved the problem of needing to add mold processes or pneumatic / hydraulic assistance for multi-stage negative angle forming. An innovative automotive mold for multi-stage negative angles was developed. This invention relates to a pre-accelerated forming device and its operating method. The device primarily addresses the challenges of low-stroke, small-space descent using pre-acceleration and a bidirectional propulsion structure. It pre-decomposes the motion and applies bidirectional force, creating a dynamic, variable-speed motion. This solves problems such as locking and low speed during lateral movements at small angles and reduced mold height. The device utilizes a variable-track moving forming block in conjunction with a retraction forming method to achieve positive forming of multi-stage negative angles. This decomposes the multi-stage negative angles into continuous, one-step forming movements, avoiding the need for additional processes, changes in stamping direction, or the introduction of auxiliary power structures for negative angles. The operating method focuses on the parameter settings and pre-treatment issues in the forming process summarized by the device's experimental technology team. This addresses the accuracy of the forming process and problems such as springback, distortion, and surface defects caused by the cold stamping die forming principle.

[0148] The pre-accelerated forming device for automotive molds with multi-stage negative angles and its application method include two parts: the forming device and the forming method, such as... Figures 1 to 6 As shown, the molding device includes 11 parts: an acceleration base 1, a low-speed guide plate 2, a pre-acceleration guide plate 3, a variable-speed molding block 4, a movable guide plate 5, a return spring 6, a variable-speed drive block 7, a limit slider 8, a pre-push slider 9, a balance guide plate 10, and a part section 11. The acceleration base 1 is fixed to the lower mold body of the mold. The low-speed guide plate 2 is installed on the acceleration base 1. The pre-acceleration guide plate 3 and the balance guide plate 10 are also installed at their corresponding positions on the acceleration base 1. All installation methods are screw fixing, thus completing the installation of the acceleration base component of the device.

[0149] The pre-forming surface 4.4, the first-order negative angle forming surface 4.5, and the second-order negative angle forming surface 4.6 of the variable speed forming block 4 are processed and formed according to the requirements of the usage method below. Then, the movable guide plate 5 is installed on the corresponding position of the variable speed forming block 4 with screws, and the reset spring 6 is installed on the reset spring mounting surface 4.2 of the variable speed forming block 4. The installation of the variable speed forming block component of the device is completed.

[0150] Install the speed drive block 7 on the upper mold, install the pre-push slider 9 in the corresponding position of the speed drive block 7 with screws, then place the assembled speed forming block component into the 7.3 (left and right symmetrical) movable surface, install the limit slider 8 on the speed drive block 7 with screws, and lock the speed forming block component into the speed drive block 7, thus completing the installation of the overall device.

[0151] At this point, after the overall mold's up-and-down movement enters the device, it can be changed into two movements of the variable-speed forming block 4. One is a lateral pre-acceleration movement under the action of the pre-acceleration guide plate 3, which performs preliminary lateral operation and pre-acceleration approach. The other is a small-angle lateral movement after the low-speed guide plate 2 contacts the low-speed sliding surface 4.7. At this time, under the dual action of the pre-acceleration guide plate 3 and the low-speed guide plate 2, coupled with the initial speed already activated, a series of problems such as locking and vibration caused by short stroke and small angle can be eliminated, achieving stable operation at high speed. The balance guide plate 10 interacts with the balance surface 7.1 to counteract the influence of the lateral force of the overall process on the structure. During the movement, the pre-forming surface 4.4, the first-order negative angle forming surface 4.5, and the second-order negative angle forming surface 4.6 of the variable speed forming block 4 can move laterally at different speeds and in different directions, thereby performing sequential forming of multi-order negative angles (at this time, the corresponding part side structure will retract the moving forming block, which can be applied in the form of rollers, lateral wedges, etc. Since relevant technologies are available, they will not be described in detail). With the experimental parameters in the usage method section below, the precise forming of multi-order negative angles can be achieved.

[0152] The method of use is mainly based on experimental and calculation data, systematically configuring the pre-acceleration and low-speed relationship, implementing molding layout in conjunction with pre- and post-molding processes, and compiling optimal solution data for common quality problems. It includes process handling and layout to optimize the overall molding process; device pre-acceleration and low-speed settings to select appropriate motion trajectories and spaces; and systematic process innovations to eliminate quality problems, as well as device parameter calculation and adjustment methods to achieve optimal quality. Specific details are as follows:

[0153] 1. Process Handling and Layout: For flanging areas with multiple negative angles, if the preceding processes only involve drawing and trimming, or if the multiple negative angle surfaces are not straight lines but rather have inner or outer arcs or other curved shapes, then pre-bending should be performed during the drawing process to solidify the planar surface and prevent stress from subsequent multi-stage flanging from affecting the overall product condition. The pre-bending position is at the junction of the planar surface and the first-stage bend. During shaping, the drawing depth should be 30%–50% of the first-stage negative angle bend height. The specific selection can be made based on the risk assessment of the forming calculation. At the same time, the fillet at the overlap with the planar surface should be enlarged compared to the actual required fillet. Specifically, if the fillet is less than R5, enlarge it by R1; otherwise, enlarge it by R2 to allow space for strong pressure bending during negative angle forming. If the preceding process can arrange for a flanging operation and the multi-stage negative angle surface is a straight line or approximately a straight line, then the pre-bending shape is not performed in the preceding drawing process. Instead, a flanging process is set in the process after drawing and before the multi-stage negative angle forming process, with a flanging angle of 90 degrees and no enlargement of the flanging radius.

[0154] 2. Device pre-acceleration and low-speed settings:

[0155] 2.1 Angle and height settings of pre-acceleration guide plate 3: When the required first-order negative angle is a multiple of 5, the angle of the first-order negative angle is directly selected as the angle between the pre-acceleration guide plate 3 and the pre-acceleration force surface 4.1; when the required first-order negative angle is not a multiple of 5, it is rounded to a multiple of 5 according to the size of the angle.

[0156] Its height (vertical direction, not inclined direction) H is related to the first negative angle height, the second negative angle height, and the maximum allowable height of the mold cavity. According to experimental data, its height is at least 4 times the first negative angle height + the second negative angle height.

[0157] 2.2, Setting the angle of the low-speed guide plate 2: The angle of the low-speed guide plate should be set to be consistent with the angle of the second-order negative angle.

[0158] 2.3, Rounding of second-order negative angles: In order to optimize the forming process, maintain forming stability and reduce the impact of springback, the rounding of second-order negative angles needs to be sharpened. The processing method is as follows: when the rounding of the second-order negative angle is less than R5, the rounding is reduced by R0.7, and vice versa.

[0159] 3. Other parameter calculation and adjustment methods: The adjustment of other parameters is mainly to obtain the experimental optimal solution, which involves the adjustment and setting of the preformed surface 4.4, the first-order negative angle forming surface 4.5, and the second-order negative angle forming surface 4.6.

[0160] 3.1, Setting the height and angle of the preformed surface 4.4: The angle of the preformed surface 4.4 should be 90 degrees vertically. Its height is set according to the previous preformed condition. If there is a previous preformed condition, its height is 1.5-2 times the length of the first negative angle + the length of the second negative angle (note that this is the length, not the height). If there is no previous preformed condition but it is a flange, its height is 0.8-1.2 times the length of the first negative angle + the length of the second negative angle. If there is no previous operation, its height is 1.2-2 times the length of the first negative angle + the length of the second negative angle.

[0161] 3.2 The first-order negative angle forming surface 4.5 is adjusted and set. To reduce the impact of quality problems such as springback and torsion, the width of the first-order negative angle forming surface 4.5 should be consistent with the width of the first-order negative angle of the product. Simultaneously, the first-order negative angle forming surface 4.5 has undergone forming treatment, which involves increasing the cutting angle by 0.8-1.2 degrees. The value is selected within this range based on the thickness of the part material and its elasticity.

[0162] 3.3 Adjustment settings for the second-order negative angle forming surface 4.6: The width of the second-order negative angle forming surface 4.6 should be more than 0.7 times the width of the second-order surface of the part. The angle increase method is the same as that of the first-order negative angle forming surface 4.5, and the increase range is between 1 and 2 degrees.

[0163] 4. Application examples of the device are shown below.

[0164] The installation process is shown in the figure:

[0165] 1. Fix the acceleration base 1 on the lower mold body, install the low-speed guide plate 2 on the acceleration base 1, and install the pre-acceleration guide plate 3 and the balance guide plate 10 on the corresponding positions of the acceleration base 1. All are installed by screw fixing, thus completing the installation of the acceleration base component of the device.

[0166] 2. The pre-forming surface 4.4, the first-order negative angle forming surface 4.5, and the second-order negative angle forming surface 4.6 of the variable speed forming block 4 are processed and formed according to the requirements of the method section, so that each forming working surface can meet the test requirements and complete the sequential forming operation.

[0167] 3. Then, the movable guide plate 5 is installed on the corresponding position of the speed-changing forming block 4 with screws. Its function is to improve wear resistance and facilitate the adjustment of the gap value between the movable surface 7.3 on the speed-changing forming block 4 and the speed-changing drive block 7, so as to achieve a smooth sliding effect.

[0168] 4. Install the reset spring 6 on the reset spring mounting surface 4.2 of the speed-changing forming block 4, so that the reset spring 6 can store energy when the speed-changing drive block 7 pushes forward. This completes the installation of the speed-changing forming block component of the device.

[0169] 5. Install the speed drive block 7 on the upper mold, and install the pre-push slider 9 in the corresponding position of the speed drive block 7 with screws to increase the smoothness and wear resistance of the speed forming block 4, maintain accuracy and facilitate gap adjustment, and provide a simple and adjustable means to adjust the forming gap in the later stage to ensure the surface quality.

[0170] 6. Place the assembled variable speed forming block component into the movable surface 7.3 (symmetrical left and right). At this time, the movable surface 7.3 is in contact with the movable guide plate 5, the pre-acceleration force-bearing surface 4.1 is in contact with the pre-acceleration pushing surface 7.2, and the pre-push surface 4.3 is in contact with the pre-push slider 9. Use screws to install the limit slider 8 on the variable speed drive block 7, and lock the variable speed forming block component into the variable speed drive block 7, so that the variable speed forming block component can only slide inside the variable speed drive block 7, forming a complex control mode of single-direction movement at the top and bidirectional movement at the bottom, thus completing the installation of the overall device.

[0171] Applications such as Figures 7 to 11 As shown:

[0172] I. Achieving multi-stage negative angle pre-accelerated molding function

[0173] 1. Adjust and process the parameters of the device according to the parameter calculation steps, and install it according to the installation process steps to form the installation state.

[0174] 2. When the mold starts running, the upper mold moves upward. At this time, the upper mold drives the variable speed forming block component and the variable speed drive block component to move upward. The variable speed forming block component is constrained by the return spring 6 and the return spring limit surface 7.4 and by gravity, and stays below the variable speed drive block 7. A cavity appears between the upper and lower molds. The part to be formed is placed into the mold to prepare for forming.

[0175] 3. When molding begins, the upper mold moves downward, the balance guide plate 10 contacts the balance surface 7.1, limiting the up and down movement of the device and counteracting the lateral force brought by the preforming surface 4.4 forming the part 11 vertically at the same time, so as to achieve a steady state of operation of the device and complete the forming operation of the part 11 by the preforming surface 4.4.

[0176] 4. The upper mold continues to descend. At this point, the pre-forming surface 4.4 has completed the forming of the rounded corner of part 11 and begins to enter the pre-acceleration stage. The high-speed sliding surface 4.8 and the pre-acceleration guide plate 3 are constrained by the variable speed drive block component and the pre-acceleration guide plate 3. At this time, the variable speed forming block 4 makes lateral movement. The first-order negative angle forming surface 4.5 forms the first-order negative angle surface of part 11. At this time, the balance guide plate 10 contacts the balance surface 7.1 to balance the lateral force. The high-speed sliding surface 4.8 and the pre-acceleration guide plate 3 cooperate to slide and control the direction of movement. The pre-acceleration force-bearing surface 4.1 and the pre-acceleration pushing surface 7.2 make symmetrical compensation lateral movement acceleration to prevent a series of problems such as vibration and inaccurate movement caused by the unidirectional wedge. As the upper mold continues to descend, the forming of the first-order negative angle surface of part 11 can be completed.

[0177] 5. As the first-order negative angle surface is formed, when the mold continues to descend, the low-speed sliding surface 4.7 contacts the low-speed guide plate 2. At this time, the second-order negative angle forming surface 4.6 on the variable speed forming block 4 starts to work. The second-order negative angle forming surface 4.6 starts to push the part 11 to form the second-order negative angle surface, change the forming direction, and form the second-order negative angle. At this time, the balance guide plate 10 contacts the balance surface 7.1 to continuously balance the lateral force. The high-speed sliding surface 4.8 and the pre-acceleration guide plate 3 slide together as an auxiliary driving force source for small angle forming. The movement of the low-speed sliding surface 4.7 and the low-speed guide plate 2 serves as a guiding and determining device for the second-order negative angle forming. The pre-acceleration force surface 4.1 and the pre-acceleration pushing surface 7.2 perform symmetrical compensation lateral movement acceleration. Through acceleration compensation and small angle forming auxiliary pushing, a series of problems such as locking, vibration, and poor speed in small stroke, small space, and small angle forming are eliminated. With the parameter calculation of the test data, the accurate forming of high-quality multi-order negative angle structures can be easily completed.

[0178] 6. After molding is completed, the return process is the opposite motion, which will not be described in detail.

[0179] A brief introduction to the convenient adjustment method for craftsmen: The gap between the pre-push slider 9 and the part 11 during each motion trajectory can be adjusted by adjusting the thickness of the low-speed guide plate 2, the pre-acceleration guide plate 3, and the pre-push slider 9, thereby correcting dimensional tolerance problems, surface problems, and work hardening problems, and assisting craftsmen in making adjustments.

[0180] II. The device is only intended for use as an anti-lock and anti-vibration device for small-angle forming.

[0181] In actual production applications, in addition to multi-stage negative angle forming, there are many small-angle and short-stroke lateral forming situations. In this case, it is only necessary to process the pre-forming surface 4.4, the first-stage negative angle forming surface 4.5, and the second-stage negative angle forming surface 4.6 on the variable speed forming block 4 and replace them with inclined or vertical mounting surfaces. Then, the forming block that needs to perform the forming action can be installed on it to achieve the anti-locking and anti-vibration effect for small-angle forming and to enable high-speed movement.

[0182] Any aspects of this technical solution that are not detailed herein are conventional technical means known to those skilled in the art.

[0183] The above content shows and describes the basic principles, main features, and beneficial effects of this technical solution. The above description is merely a preferred embodiment of this technical solution and is not intended to limit the scope of this technical solution. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this technical solution should be included within the protection scope of this technical solution.

Claims

1. A pre-accelerated forming device for automotive molds with multi-stage negative angles, characterized in that, It includes an acceleration base, a guide assembly, a variable speed forming assembly, a variable speed drive assembly, and a reset assembly; the acceleration base is used to fix to the lower mold body of the mold, the guide assembly is installed on the acceleration base, the variable speed drive assembly is used to fix to the upper mold, the variable speed forming assembly is slidably assembled in the variable speed drive assembly, and the reset assembly is located between the variable speed forming assembly and the variable speed drive assembly. The guiding assembly includes a pre-acceleration guide plate and a low-speed guide plate. The pre-acceleration guide plate is used to drive the variable speed forming assembly to generate lateral pre-acceleration motion, and the low-speed guide plate is used to drive the variable speed forming assembly to generate low-speed lateral forming motion that matches multi-stage negative angle forming. The variable speed forming component is provided with a pre-forming surface, a first-order negative angle forming surface and a second-order negative angle forming surface arranged in sequence. Under the sequential action of the pre-acceleration guide plate and the low-speed guide plate, the variable speed forming component can drive the pre-forming surface, the first-order negative angle forming surface and the second-order negative angle forming surface to form the corresponding surface in sequence through timed lateral movement.

2. The pre-accelerated forming device for automotive molds with multi-stage negative angles according to claim 1, characterized in that, The guiding assembly further includes a balance guide plate, which is fixed on the acceleration base. The speed change drive assembly includes a speed change drive block, which has a balance surface that is slidably adapted to the balance guide plate. The balance guide plate and the balance surface cooperate to counteract the lateral force during the lateral forming process.

3. The pre-accelerated forming device for automotive molds with multi-stage negative angles according to claim 1 or 2, characterized in that, The variable speed forming component includes a variable speed forming block. The pre-forming surface, the first-order negative angle forming surface, and the second-order negative angle forming surface are all located at the forming end of the variable speed forming block. The variable speed forming block is provided with a pre-acceleration force-bearing surface, a high-speed sliding surface, and a low-speed sliding surface. The pre-acceleration force-bearing surface is matched with the tilt angle of the pre-acceleration guide plate. The high-speed sliding surface is slidably adapted to the pre-acceleration guide plate. The low-speed sliding surface is slidably adapted to the low-speed guide plate.

4. The pre-accelerated forming device for automotive molds with multi-stage negative angles according to claim 3, characterized in that, The tilt angle of the pre-acceleration guide plate matches the first negative angle of the part to be formed, and the tilt angle of the low-speed guide plate is consistent with the second negative angle of the part to be formed; the vertical height of the pre-acceleration guide plate along the mold closing direction is not less than 4 times the sum of the first negative angle height and the second negative angle height.

5. The pre-accelerated forming device for automotive molds with multi-stage negative angles according to any one of claims 1, 2, and 4, characterized in that, The variable speed drive assembly includes a variable speed drive block, a limiting slider, and a pre-push slider. The variable speed drive block has symmetrical movable surfaces. Movable guide plates are fixed on both sides of the variable speed molding assembly. The variable speed molding assembly slides with the movable surfaces through the movable guide plates. The limiting slider is fixed on the variable speed drive block to limit the sliding stroke of the variable speed molding assembly. The pre-push slider is fixed on the variable speed drive block and slides with the pre-push surface of the variable speed molding assembly.

6. The pre-accelerated forming device for automotive molds with multi-stage negative angles according to claim 5, characterized in that, The reset assembly includes a reset spring, the speed-changing forming assembly has a reset spring mounting surface, the speed-changing drive assembly has a reset spring limiting surface, and the two ends of the reset spring respectively abut against the reset spring mounting surface and the reset spring limiting surface.

7. A method of using a pre-accelerated forming device for automotive molds with multi-stage negative angles, characterized in that, The following steps are performed using the automotive mold pre-acceleration forming device for multi-stage negative angles as described in any one of claims 1-6: S1 Process Pre-treatment and Layout: Based on the surface characteristics of the multi-stage negative angle area of ​​the part to be formed, the preceding pre-treatment process is set up; S2 device parameter configuration: Based on the multi-order negative angle parameters of the part to be formed, configure the angle and height parameters of the pre-acceleration guide plate and the low-speed guide plate, as well as the parameters of each forming surface on the variable speed forming assembly; S3 device assembly: Fix the acceleration base to the lower mold, install the guide component on the acceleration base, fix the speed change drive component to the upper mold, and slide the speed change forming component with the reset component assembled into the speed change drive component to complete the overall assembly of the device. S4 stamping: Control the upper and lower molds to close, and drive the variable speed forming components in sequence through the guide components to complete the pre-accelerated lateral movement and low-speed lateral forming movement, so that each forming surface can complete the pre-forming, first-order negative angle forming and second-order negative angle forming in sequence, realizing the single-process one-time forming of multiple negative angles; S5 mold opening and return stroke: The mold opens and moves upward, and the speed forming component is reset under the action of the reset component to complete a single stamping cycle.

8. The method of using the pre-accelerated forming device for automotive molds with multi-stage negative angles according to claim 7, characterized in that, In step S1, if the multi-stage negative angle surface of the part to be formed is a curved shape and the preceding process only involves drawing and trimming, then a pre-bending shape is set in the drawing process. The drawing depth of the pre-bending is 30%-50% of the bending height of the first-stage negative angle, and the fillet of the pre-bending point overlapping the plane is enlarged by R1-R2 compared to the actual required fillet. If the multi-stage negative angle surface of the part to be formed is a straight line and a flanging process can be set in the preceding process, then a flanging process is set after drawing and before the multi-stage negative angle is formed, and the flanging angle is 90 degrees.

9. The method of using the pre-accelerated forming device for automotive molds with multi-stage negative angles according to claim 7 or 8, characterized in that, In step S2, the parameter configuration for each forming surface is as follows: The angle of the preformed surface is 90 degrees, and its height is set to 0.8-2 times the sum of the first-order negative angle length and the second-order negative angle length, depending on the previous pretreatment. The width of the first-order negative angle forming surface is consistent with the width of the first-order negative angle of the part, and it has been formed, with the cutting angle increased by 0.8-1.2 degrees; The width of the second-order negative angle forming surface is not less than 0.7 times the width of the second-order surface of the part, and it has been formed. The cutting angle is increased by 1-2 degrees. The rounded corner of the second-order negative angle is sharpened and reduced by R0.7-R1 compared with the designed rounded corner.

10. The method of using the pre-accelerated forming device for automotive molds with multi-stage negative angles according to claim 9, characterized in that, It also includes step S6 adjustment and optimization: by adjusting the thickness of the low-speed guide plate, the pre-acceleration guide plate, and the pre-pushing slider, the forming gap of the variable speed forming component is adjusted, and the forming size and surface defects of the parts are corrected.

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