Dragging arm stamping and welding process

Abstract

The invention relates to the technical field of automobile part manufacturing, in particular to a trailing arm stamping and welding process, which comprises the following steps of: uncoiling by using a servo drive uncoiling machine matched with a four-roller precision leveling machine, leveling a coiled material for multiple times, and blanking by using a numerical control plate shearing machine to obtain a plate blank; drawing the left / right trailing arm blank into the basic shape of the trailing arm on a drawing die, and trimming and punching by using a high-precision punching machine and a hydraulic machine; then, a vertical flanging die and a floating type side shaping die are used for flanging and side shaping, and the workpiece is rolled into a closed pipe shape; then, double-wire welding is adopted on a special clamp to conduct high-speed welding on a welding seam of the workpiece; 3D laser cutting equipment is used, a visual tracking system is arranged, the variable cross-section pipe is precisely cut, the size precision and the shape precision of the left trailing arm and the right trailing arm are effectively guaranteed, and the problems that in the prior art, precision control is difficult, efficiency and cost are contradictory, and process compatibility is poor are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automobile parts manufacturing, and particularly relates to a stamping and welding process of a trailing arm. BACKGROUND

[0002] As one of the core parts of the torsion beam assembly, the trailing arm plays a vital role in the automobile chassis structure. Its unique structural characteristics, including hollow tubular, closed curve cross-section and large variation of cross-sectional circumference, etc., pose extremely stringent requirements on the manufacturing process. Not only is it necessary to ensure extremely high manufacturing precision to meet the stability and reliability requirements of the automobile chassis structure, but it is also necessary to have high production efficiency to adapt to the rhythm of large-scale batch production of automobiles. At the same time, cost control is also a key factor. On the premise of ensuring quality, production cost should be reduced as much as possible to improve the market competitiveness of the product.

[0003] In the prior art, the stamping and welding of the trailing arm includes the following: 1. Tube making from coil - internal high-pressure bulging process, which includes coil uncoiling and flattening to make tube → high-frequency welding or laser welding → preforming → internal high-pressure bulging → laser cutting. Technical features: the cross-sectional circumference change is realized by internal high-pressure bulging, but it needs to be matched with internal high-pressure equipment and molds, the mold cost is high (the cost of a single mold exceeds one million yuan), and the uniformity of the material wall thickness during the bulging process is difficult to control (the wall thickness deviation can reach ±0.3mm), which is prone to local cracking or wrinkling. Limitations: large equipment investment, suitable for large-scale production, but the cost is high when small batches are produced; the process parameters (pressure, temperature) are sensitive, the debugging period is long, and the mold modification is difficult. Not suitable for products with too large cross-sectional circumference change.

[0004] 2. Split stamping-welding process, which includes the following process path: the trailing arm is divided into upper and lower parts → respectively stamped and formed → welded and combined. Technical features: the mold structure is simplified by split stamping, but additional positioning tooling (positioning error ±0.2mm) is needed during welding assembly, and the overall shape and position tolerance (straightness, flatness) after welding is difficult to guarantee (error can reach ±0.5mm), which needs subsequent shaping process. Limitations: the split structure leads to an increase of more than 50% in the length of the weld, the risk of welding thermal deformation is high, and the lightweight of the part is limited (because the welding lap edge needs to be reserved, the material utilization rate is reduced by 10%-15%), and the accuracy of the single piece is high.

[0005] 3. Sheet metal one-stroke stamping-high-speed welding process, the process path includes: coil uncoiling and leveling blanking → sheet metal stamping into a hollow tubular → high-speed welding to close the section → 3D laser cutting. Technical features: sheet metal can meet the products with large changes in cross-sectional circumference through stamping processes such as drawing, trimming, shaping and flanging, reducing the risk of local cracking or wrinkling. The sheet piece is welded by high-speed welding (such as resistance welding), and the heat-affected zone is about 2-3 mm wide, and the weld strength fluctuates greatly (tensile strength deviation ± 15 MPa).

[0006] In summary, the existing stamping and welding mode of the trailing arm has the problems of difficult precision control, contradiction between efficiency and cost, and poor process compatibility. SUMMARY

[0007] The purpose of the present application is to provide a trailing arm stamping and welding process, which aims to solve the technical problems of difficult precision control, contradiction between efficiency and cost, and poor process compatibility in the prior art.

[0008] To achieve the above-mentioned purpose, a trailing arm stamping and welding process is adopted, which includes the following steps: First, a servo-driven uncoiler is used to uncoil the coil and level it multiple times, and then a numerical control shearing machine is used to cut the sheet blank to obtain the sheet blank; Then, the left / right trailing arm blank is drawn into a basic shape of the trailing arm on a drawing die; Then, a high-precision punch or hydraulic machine is used to trim and punch the drawing process piece; Then, a vertical flanging die and a floating side shaping die are used for flanging and side shaping respectively to correct the shape accuracy of the trailing arm, and the process piece is rolled into a closed tubular shape; Then, a double-wire welding machine is used to weld the process piece at high speed on a special fixture; a 3D laser cutting device is used, and a visual tracking system is provided to accurately cut the variable cross-section tube to obtain the left / right trailing arm product.

[0009] In the step of "first, a servo-driven uncoiler is used to uncoil the coil and level it multiple times, and then a numerical control shearing machine is used to cut the sheet blank to obtain the sheet blank", the specific mode is as follows: The servo-driven uncoiler is used to uncoil and level the coil, the uncoiling speed is controlled at 5-8 m / min, the tension control accuracy is ±5N, and the flatness is ≤0.5mm / m after 3 times of reciprocating leveling 2 ; The numerical control shearing machine is used to cut the sheet blank according to the expanded size, and the internal stress of the coil is eliminated through tension closed-loop control, so that the yield strength fluctuation of the leveled sheet is ≤5MPa.

[0010] In the step of "drawing the left / right dragging arm blank on the drawing die into a dragging arm basic shape", the die working surface is treated with a special surface treatment, the drawing speed is 10-15 mm / s during working, and the wall thickness reduction rate is controlled within 8%-12%.

[0011] In the step of trimming and punching the formed blank, a high-precision punch and a hydraulic press are used for trimming and punching; a stepped punch and die are used for trimming, the punching diameter tolerance is ±0.1 mm, the position tolerance is ±0.15 mm, and a guide pin is used for secondary positioning.

[0012] In the step of flanging and shaping the product after the punching process: The flanging and shaping are performed by using a vertical flanging die, the punch is provided with an elastic polyurethane pad, the die is provided with a limiting block with an adjusting function, the shaping pressure is 300-500 kN, and the pressure holding time is 2-3 s. In the step of flanging and shaping the product after the punching process: The flanging and shaping are performed by using a vertical flanging die, the punch is provided with an elastic polyurethane pad, the die is provided with a limiting block with an adjusting function, the shaping pressure is 300-500 kN, and the pressure holding time is 2-3 s.

[0013] In the step of flanging and shaping the product after the punching process: The flanging and shaping are performed by using a vertical flanging die, the punch is provided with an elastic polyurethane pad, the die is provided with a limiting block with an adjusting function, the shaping pressure is 300-500 kN, and the pressure holding time is 2-3 s. In the step of flanging and shaping the product after the punching process: The flanging and shaping are performed by using a vertical flanging die, the punch is provided with an elastic polyurethane pad, the die is provided with a limiting block with an adjusting function, the shaping pressure is 300-500 kN, and the pressure holding time is 2-3 s.

[0014] In the step of flanging and shaping the product after the punching process: The flanging and shaping are performed by using a vertical flanging die, the punch is provided with an elastic polyurethane pad, the die is provided with a limiting block with an adjusting function, the shaping pressure is 300-500 kN, and the pressure holding time is 2-3 s. In the step of flanging and shaping the product after the punching process:

[0015] In the step of flanging and shaping the product after the punching process: In the step of flanging and shaping the product after the punching process: In the step of flanging and shaping the product after the punching process:

[0016] In the step of flanging and shaping the product after the punching process: In the step of flanging and shaping the product after the punching process: In the step of flanging and shaping the product after the punching process: In the step of flanging and shaping the product after the punching process:

[0017] The stamping and welding process of the trailing arm of the present application, in specific use, first adopts a servo-driven decoiler matched with a four-roller precision leveler to uncoil and level the coil material multiple times, and then adopts a numerical control plate shearing machine to cut and obtain the plate blank; then the left / right trailing arm blank is drawn into a basic shape of the trailing arm on a drawing die; then a high-precision punch or a hydraulic machine is used to trim and pierce the drawn workpiece; then a vertical flanging die and a floating side shaping die are used for flanging and side shaping respectively, and the shape accuracy of the trailing arm is corrected, and the workpiece is rolled into a closed tubular shape; then a special fixture is used to weld the workpiece at high speed by double-wire welding; a 3D laser cutting equipment is used, and a visual tracking system is equipped, to accurately cut the variable cross-section pipe to obtain the left / right trailing arm product, so as to solve the technical problems of the existing trailing arm stamping and welding mode, such as difficult precision control, contradiction between efficiency and cost, and poor process compatibility. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative effort.

[0019] Figure 1 is a step flow chart of the stamping and welding process of the trailing arm of the present application. DETAILED DESCRIPTION

[0020] The embodiments of the present application will be described in detail below, and the examples of the embodiments are shown in the drawings. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0021] Please refer to Figure 1 , Figure 1 is a step flow chart of the stamping and welding process of the trailing arm of the present application.

[0022] The present application provides a stamping and welding process of a trailing arm, comprising the following steps: S1, first adopt a servo-driven decoiler matched with a four-roller precision leveler to uncoil and level the coil material multiple times, and then adopt a numerical control plate shearing machine to cut and obtain the plate blank; For this specific embodiment, the specific manner is as follows: The four-roll precision leveling machine matched with the servo-driven uncoiler is used to uncoil and level the coil stock, the uncoiling speed is controlled at 5-8 m / min, the tension control precision is ±5 N, and the plane degree is less than or equal to 0.5 mm / m after three reciprocating leveling 2 ; The numerical control plate shearing machine is used to cut the plate according to the size of the expanded material, and the internal stress of the coil stock is eliminated through tension closed-loop control, so that the yield strength fluctuation of the leveled plate is less than or equal to 5 MPa.

[0023] S2, then the left / right trailing arm blank is drawn on the drawing die to form a trailing arm basic shape; For this specific embodiment, the die working surface is treated with a special surface treatment, and the drawing speed during operation is 10-15 mm / s, and the wall thickness reduction rate is controlled at 8%-12%.

[0024] S3, then the high-precision punch or hydraulic machine is used to trim and punch the drawn process piece; For this specific embodiment, when the formed blank is trimmed and punched, a high-precision punch and a hydraulic machine are used for trimming and punching; a stepped punch and die trimming is used, the punching diameter tolerance is ±0.1 mm, the position tolerance is ±0.15 mm, and a guide pin is used for secondary positioning.

[0025] S4, then the vertical flanging die and the floating side shaping die are used for flanging and side shaping respectively to correct the shape accuracy of the trailing arm, and the process piece is rolled into a closed tubular shape; For this specific embodiment, when the punched product is flanged and shaped: The flanging shaping uses a vertical flanging die, the punch uses an elastic polyurethane pad, the die is provided with a limiting block with adjusting function, the shaping pressure is 300-500 kN, and the pressure holding time is 2-3 s; The hardness of the punch is Shore 80A, and the travel adjustment accuracy of the limiting block with adjusting function is 0.01 mm.

[0026] When the punched product is flanged and shaped: The side shaping uses a floating side shaping die, the left and right dies are fed synchronously to ensure the parallelism and straightness of the two sides of the trailing arm; The speed difference of the left and right dies is less than or equal to 0.05 mm / s when they are fed synchronously.

[0027] When the process piece is made into a closed tubular shape by using the circle shaping die: The final gap is 0.5±0.2 mm, and the straightness is less than or equal to 0.2 mm / m.

[0028] The measurement accuracy of the digital curvature measuring instrument is ±0.02 mm, the curvature radius R is 50-80 mm when the flat plate blank is rolled into a U-shaped plate, and the minimum roll gap of the adjustable roll gap is 5 mm.

[0029] S5, then the high-speed welding of the process piece is carried out on the special fixture by using double-wire welding; the variable cross-section pipe is accurately cut by using a 3D laser cutting device and being equipped with a visual tracking system, so that the left / right tow arm product is obtained.

[0030] For this specific embodiment, when laser welding is performed: The left / right tow arm process piece is positioned and fixed at the same time on the special fixture by using a positioner and a rotary table, and robot welding is performed by using double-wire welding, so as to ensure the consistency of the weld, the welding gas flow is 15-20 L / min as the protective gas for welding, the welding speed is 5-8 mm / s, and the defocusing amount is +1 mm.

[0031] When laser cutting is performed; In the step of using a special positioning tool and being equipped with a rotary table, the left / right tow arm is cut at the same time by using a 3D laser cutting device, so as to ensure that the cooperation gap with the left and right brake plates is uniform, and to ensure that the gap at each place is ≤1.0 mm. The pulse laser frequency is 50-100 Hz, the pulse width is 0.1-0.3 ms, and the cutting speed is 10-15 mm / s; The pulse laser frequency is 50-100 Hz, the pulse width is 0.1-0.3 ms, and the cutting speed is 10-15 mm / s;

[0032] At the same time, the cut tow arm enters the post-processing and inspection link, the post-processing includes deburring and cleaning, when deburring, the machine vision algorithm is used to accurately identify the position and size of the burr, and the control system adjusts the deburring equipment parameters accordingly; in the cleaning link, a database is established by collecting past data, machine learning algorithm is used to intelligently optimize the cleaning process parameters, and path planning algorithm is used to plan the optimal motion trajectory for the cleaning equipment; Then, the three-coordinate measuring instrument and non-destructive testing equipment are used for comprehensive inspection, the qualified products are packaged and stored, and the unqualified products are marked and returned to work or scrapped.

[0033] The present application discloses a kind of drag arm stamping, welding process using the present application, in specific use, first using servo drive decoiler supporting four-roll precision leveller to carry out decoiling to roll material and multiple leveling, then using numerical control plate shearing machine to carry out blanking and obtain plate blank, then using multi-station progressive die cooperates hydraulic servo drive equipment to blank drawing forming, forms the basic shape of drag arm;Then using high-precision punch supporting numerical control feeding system to the blank after forming carries out trimming and punching processing;After that, vertical flanging die and floating type side shaping die are used to carry out flanging and side shaping respectively, and the shape accuracy of drag arm is corrected;Three-roll coiling machine is used to coil the blank after side shaping into closed tubular;Closed tubular blank is welded into a whole by using optical fiber laser welding machine supporting five-axis linkage welding tooling;Finally, five-axis laser cutting machine is used to carry out precision cutting to the welded drag arm, and the drag arm is obtained, so as to solve the technical problems of precision control difficulty, efficiency and cost contradiction and poor process compatibility of the existing drag arm stamping and welding mode.

[0034] The above only discloses a preferred embodiment of the present application, of course cannot limit the scope of the present application, and those skilled in the art can understand that the above-mentioned embodiment can be implemented by all or part of the process, and equivalent changes made according to the claims of the present application still belong to the scope covered by the present application.

Claims

1. A drag arm stamping and welding process, characterized in that it comprises the following steps: First, a servo-driven decoiler is used to uncoil the coil stock and multiple times to flatten it, and then a numerical control plate shearing machine is used to cut the plate stock to obtain a plate blank; Next, the left / right drag arm blank is drawn into a basic shape of the drag arm on a drawing die; Then, a high-precision punch or hydraulic press is used to trim and punch the drawing process piece; After that, a vertical flanging die and a floating side shaping die are used for flanging and side shaping, respectively, to correct the shape accuracy of the drag arm and roll the process piece into a closed tubular shape; Then, a special fixture is used to weld the process piece at high speed using double-wire welding; a 3D laser cutting device is used, and a visual tracking system is provided to accurately cut the variable cross-section tube to obtain the left / right drag arm product.

2. The drag arm stamping and welding process of claim 1, characterized in that in the step of "first, a servo-driven decoiler is used to uncoil the coil stock and multiple times to flatten it, and then a numerical control plate shearing machine is used to cut the plate stock to obtain a plate blank", the specific method is as follows: The numerical control plate shearing machine is used to cut the plate stock according to the expanded size, and the internal stress of the coil stock is eliminated through tension closed-loop control, so that the yield strength fluctuation of the flattened plate stock is ≤5MPa.

3. The drag arm stamping and welding process of claim 2, characterized in that in the step of "the left / right drag arm blank is drawn into a basic shape of the drag arm on a drawing die", the die working surface is treated with a special surface treatment, and the drawing speed during work is 10-15mm / s, and the wall thickness reduction rate is controlled within 8%-12%. The four-roller precision leveling machine is used to open and level the coil with the servo drive uncoiler, the opening speed is controlled at 5-8 m / min, the tension control precision is ±5 N, and the plane degree is less than 0.5 mm / m after three times of reciprocating leveling 2 ​ 4. The drag arm stamping and welding process of claim 3, characterized in that when the formed blank is trimmed and punched, a high-precision punch or hydraulic press is used for trimming and punching; a stepped punch and die set is used for trimming, the punching diameter tolerance is ±0.1mm, the position tolerance is ±0.15mm, and a pilot pin is used for secondary positioning.

5. The drag arm stamping and welding process of claim 1, characterized in that when the punched product is flanged and shaped: The flanging and shaping is performed using a vertical flanging die, the punch uses an elastic polyurethane pad, the die is equipped with a limiting block with adjustment function, the shaping pressure is 300-500kN, and the holding time is 2-3s; The hardness of the punch is Shore 80A, and the travel adjustment accuracy of the limiting block with adjustment function is 0.01mm.

6. The drag arm stamping and welding process of claim 5, characterized in that when the punched product is flanged and shaped: The side shaping is performed using a floating side shaping die, the left and right dies are fed synchronously to ensure the parallelism and straightness of the two sides of the drag arm; The speed difference of the left and right dies when they are fed synchronously is ≤0.05mm / s.

7. The drag arm stamping and welding process of claim 6, characterized in that when the process piece is made into a closed tubular shape using a circle shaping die: The final gap is 0.5±0.2mm, and the straightness is ≤0.2mm / m.

8. The drag arm stamping and welding process of claim 7, characterized in that when laser welding is performed: ​ ​ ​ ​ ​ ​ ​ ​ In the use of the positioner and rotary table, the left / right tow arm process piece is positioned and fixed at the same time in the special fixture, and the robot welding is carried out by using double wire welding, so as to ensure the consistency of the weld, the welding is carried out by using 15-20L / min of gas flow as the protective gas, the welding speed is 5-8mm / s, and the defocusing amount is +1mm.

9. The tow arm stamping and welding process according to claim 8, characterized in that, When laser cutting is performed; In the step of using a special positioning tool and being equipped with a rotary table, the left / right tow arm is cut at the same time by using a 3D laser cutting device, so as to ensure that the gap cooperated with the left and right brake plates is uniform, and ensure that the gap at each place is ≤1.0mm: The pulse laser frequency is 50-100Hz, the pulse width is 0.1-0.3ms, and the cutting speed is 10-15mm / s. The pulse laser frequency is 50-100Hz, the pulse width is 0.1-0.3ms.

Images