Clamp and welding system for laser brazing of automobile rear cover

Abstract

The invention provides a clamp and a welding system for automobile rear cover laser brazing, and relates to the technical field of automobile body-in-white manufacturing, the system is arranged inside and outside a laser protection room, and comprises a dust removal mechanism, a water cooling machine, a control cabinet and a monitoring and display system which are located outside, the laser generator, the robot body, the rear cover positioning mechanism, the test welding table and the power meter are located inside. The rear cover positioning mechanism is provided with a special clamp and comprises a base, a driving device, a plurality of pressing and supporting units, a jacking device, guiding equipment and the like, accurate positioning and stable clamping of workpieces can be achieved, and part of the pressing units achieve stepless adjustment through electric cylinders. The system is further provided with a tail lamp box pressing unit and a connecting rod device, and the stability of the workpiece in the welding process is further guaranteed. The device is simplified in structure, short in operation takt, high in welding quality and capable of effectively avoiding the air hole defect caused by zinc steam in galvanized sheet welding and reducing the repair rate and the production cost.

Description

Technical Field

[0001] This invention relates to the field of automotive body-in-white manufacturing technology, specifically to a fixture and welding system for laser brazing of automotive rear covers. Background Technology

[0002] Laser brazing, as a key welding technology in body-in-white manufacturing, has been widely used in automobile production, especially in high-end vehicles. Currently, laser brazing is mainly applied to welding the roof, rear cover, and side skirts of automobiles, primarily due to its high weld quality and aesthetically pleasing weld appearance, which can be directly presented to consumers as part of the exterior. However, precisely because of its aesthetic appeal, the quality requirements for laser-welded seams are very high. Improving weld quality and reducing defect rates are key considerations during engineering design and development.

[0003] For laser brazing of the rear cover, besides the common V-type lap joint, there is also a fillet weld, which is most commonly seen in the lap joints of the light box and the outer panel of the rear cover. Currently, galvanized steel sheets are generally used for the outer panels of car bodies because of their better corrosion resistance. Unlike V-type lap joints, the lapped plates in fillet welds are tightly fitted together. Therefore, during laser brazing, as the welding wire and the sheet are heated, the zinc layer on the surface of the galvanized steel sheet also evaporates (zinc's volatilization temperature is around 906℃, while the actual welding temperature is much higher), making it more difficult for zinc vapor to escape. If the zinc vapor cannot quickly escape from the gap, it will be trapped in the liquid weld. As the weld cools and solidifies, the zinc vapor gradually escapes, resulting in porosity (a welding defect) on the weld surface. Porosity affects the appearance of the weld and also poses a risk of leakage. Therefore, when porosity defects occur, manual repair is necessary, increasing the workload and production costs.

[0004] Ensuring zinc vapor escape and preventing welding defects such as porosity is crucial for guaranteeing the quality of laser brazing on the back cover. Currently, two common solutions exist: 1) Mechanical bosses. In the stamping workshop, during the production of stamped parts, a boss of approximately 0.2mm is punched onto the surface of the part using a die. This boss ensures a stable gap between the two parts. Alternatively, the boss can be punched using a punching gun after the stamped parts are produced. 2) Laser bosses. Before welding, a laser is used to create a boss on the overlapping surface using the laser's hump effect, extending the boss approximately 0.2mm beyond the part surface.

[0005] However, both of these solutions require additional processing steps and are costly. Ensuring stable gaps between parts in a low-cost and efficient manner, while maintaining quality, is also a problem that needs to be solved. Summary of the Invention

[0006] To address the above problems, the present invention provides the following technical solution: a fixture and welding system for laser brazing of automotive rear covers, disposed inside and outside a laser protective enclosure, comprising: The dust removal system, water chiller, control cabinet, and monitoring display system are located outside the laser protective room; the laser generator, robot body, rear cover positioning mechanism, test welding station, and power meter are located inside the laser protective room. The laser protective room is equipped with a laser source room, and the laser generator is located inside the laser source room; The rear cover positioning mechanism, the test welding station, and the power meter are respectively located on the side of the robot body.

[0007] Preferably, the rear cover positioning mechanism is provided with a rear cover laser brazing positioning fixture, which includes a base, a driving device, a lamp box clamping device, an outer panel support device, an outer panel x-axis clamping device, a lifting device, an upper part guide device, and a grounding electrode. The lifting device is mounted on the base, and the lifting device is equipped with the upper part guide device. The lamp box clamping device is respectively mounted at both ends of the lifting device. The driving device is mounted on the base and located on the side of the lifting device. The outer plate x-axis clamping device is mounted on the base and located at one end of the lifting device. The outer plate support device is mounted above the lifting device. The grounding electrode is mounted on the base and located on the opposite side of the driving device.

[0008] Preferably, the driving device, the lamp box clamping device, the outer plate support device, the outer plate x-axis clamping device, the lifting device, and the upper part guide device are all equipped with electric cylinders, which can realize servo adjustable and stepless adjustment of clamping.

[0009] Preferably, the rear cover positioning mechanism is further provided with a taillight box clamping unit, the taillight box clamping unit is provided with a flipping cylinder, the output end of the flipping cylinder is connected to a connecting rod, one end of the connecting rod is provided with a clamping cylinder, the bottom of the connecting rod is provided with a limit block, the two sides of the connecting rod are respectively provided with body Z-direction clamping blocks, the lower part of the connecting rod is provided with body X-direction clamping blocks, and the upper part of the connecting rod is provided with a connecting block.

[0010] Preferably, a plurality of body z-axis clamping blocks are provided, and the gap between each body z-axis clamping block is set to 2mm.

[0011] Preferably, the connecting block is made of 45 steel, and the body z-axis clamping block and the body x-axis clamping block are made of beryllium bronze.

[0012] Preferably, the rear cover positioning mechanism is further provided with a linkage device, which includes a cylinder, a linkage block, a second limiting block, a pin, and an adjusting rod. The output end of the cylinder is connected to one end of the linkage block, the second limiting block is located on one side of the linkage block, the other end of the linkage block is connected to the adjusting rod, and the adjusting rod is provided with the pin.

[0013] Preferably, the adjusting rod includes a first adjusting rod and a second adjusting rod, which are connected by the pin. The cylinder can drive the first adjusting rod to move through the linkage block, so that the second adjusting rod rotates around the pin, thereby achieving vertical pressing of the taillight box in the z-direction.

[0014] Preferably, the laser protective room is equipped with a separate HIP device, which is used to supply water and gas to the laser welding equipment.

[0015] Preferably, the laser protective room is equipped with an entrance door and a roller shutter door, which are located on adjacent sides of the laser protective room. The entrance door and the roller shutter door can be used to isolate the laser.

[0016] The application employs the above technical solution and has at least the following beneficial effects: This invention has fewer processing steps, lower equipment costs, easier scheduling, and better welding quality. It eliminates the need for large flipping mechanisms or gantry mechanisms to press the outer panel, resulting in a simpler structure and fewer action sequences, which helps save cycle time and increase the accessibility of robot welding.

[0017] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the laser brazing positioning fixture for the rear cover provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the taillight box clamping unit provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the linkage device provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the taillight box and surrounding positioning device provided in an embodiment of the present invention; In the diagram: 1. Laser protective room; 101. Laser source room; 2. Dust removal mechanism; 3. Water chiller; 4. Control cabinet; 5. Monitoring and display system; 6. Laser generator; 7. Robot body; 8. Rear cover positioning mechanism; 801. Base; 802. Drive device; 803. Lamp box clamping device; 804. Outer panel support device; 805. Outer panel X-axis clamping device; 806. Lifting device; 807. Upper part guiding device; 808. Grounding electrode; 811 812. Tilting cylinder; 813. Connecting rod; 814. Clamping cylinder; 815. Limiting block; 816. Body Z-axis clamping block; 817. Body X-axis clamping block; 828. Connecting block; 829. Cylinder; 820. Linkage block; 821. Second limiting block; 822. Pin; 823. Adjusting rod; 824. First adjusting rod; 825. Second adjusting rod; 9. Test welding station and power meter; 10. HIP equipment; 11. Entrance and exit door; 12. Roller shutter door. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0021] Specific embodiments of the present invention provide a fixture and welding system for laser brazing of automotive rear covers, such as... Figure 1 As shown, the system is set up inside and outside the laser protective room 1. It is mainly used for the laser brazing process of the rear cover in the manufacturing of automobile body-in-white. It aims to improve welding quality, reduce porosity defects, and achieve low-cost and high-efficiency welding operations.

[0022] The system includes a dust removal mechanism 2, a water chiller 3, a control cabinet 4, and a monitoring and display system 5 located outside the laser protective room 1, as well as a laser generator 6, a robot body 7, a rear cover positioning mechanism 8, and a test welding station and power meter 9 located inside the laser protective room 1.

[0023] The system includes a test welding station for testing laser welding process parameters; it primarily allows for welding on test pieces to find suitable process parameters before welding on actual parts, avoiding waste. A power meter measures the power at the laser head, checking if the deviation between the set and actual laser welding power meets tolerances. The robot body 7 performs the laser welding. The laser generator 6 produces the laser beam. A water chiller cools the laser, ensuring a constant water temperature. A dust removal system extracts and filters the fumes generated during welding. The monitoring and display system 5 records the entire process, allowing maintenance and production personnel to observe the welding chamber during welding. A laser protective enclosure 1 isolates the laser beam, preventing injury during welding.

[0024] The laser protective room 1 is equipped with a laser source room 101, and the laser generator 6 is installed inside the laser source room 101 to ensure the safe isolation and stable operation of the laser source. The rear cover positioning mechanism 8 and the test welding station and power meter 9 are respectively set on the adjacent sides of the robot body 7, which facilitates the robot body 7 to perform precise welding operations and process tests.

[0025] like Figure 2-5 As shown, the rear cover positioning mechanism 8 is equipped with a rear cover laser brazing positioning fixture, which includes a base 801, a drive device 802, a lamp box clamping device 803, an outer plate support device 804, an outer plate x-direction clamping device 805, a lifting device 806, an upper part guide device 807, and a grounding electrode 808. The lifting device 806 is fixedly mounted on the base 801 and is used to lift the rear cover workpiece to a predetermined position. The upper part guide device 807 is provided on the lifting device 806 to guide the workpiece for accurate placement. Lamp box clamping devices 803 are respectively provided at opposite ends of the lifting device 806 to clamp the lamp box area of ​​the rear cover. The drive device 802 is located on the base 801 and on the side of the lifting device 806, providing power to drive the fixture's movement. The outer plate x-direction clamping device 805 is located on the base 801 and at one end of the lifting device 806, used to clamp the outer plate of the rear cover in the x-direction. The outer plate support device 804 is positioned above the lifting device 806 to support the rear cover outer plate. The grounding electrode 808 is positioned on the base 801 and on the opposite side of the drive device 802 to ensure electrical safety during the welding process. The grounding electrode 808 serves as one pole of the hot wire circuit to form a hot wire current circuit, heating the welding wire, accelerating the melting of the welding wire during the welding process, improving the welding wire melting efficiency, and reducing welding power.

[0026] Preferably, the drive device 802, the lamp box clamping device 803, the outer plate support device 804, the outer plate x-direction clamping device 805, the lifting device 806, and the upper part guide device 807 are all driven by electric cylinders, which can realize servo adjustable and stepless adjustment of clamping, thereby improving the adaptability and accuracy of the fixture.

[0027] The rear cover positioning mechanism 8 also includes a taillight box clamping unit, which comprises a tilting cylinder 811, a connecting rod 812, a clamping cylinder 813, a limiting block 814, a body Z-axis clamping block 815, a body X-axis clamping block 816, and a connecting block 817. The output end of the tilting cylinder 811 is connected to the connecting rod 812. One end of the connecting rod 812 is equipped with the clamping cylinder 813, and the bottom is equipped with the limiting block 814. The connecting rod 812 has body Z-axis clamping blocks 815 on both sides, body X-axis clamping blocks 816 below, and connecting block 817 above. The taillight box clamping unit achieves precise clamping of the rear cover taillight box area through the coordinated action of the tilting cylinder 811 and the clamping cylinder 813.

[0028] Furthermore, several Z-axis clamping blocks 815 are provided on the vehicle body, with a gap of 2mm between each Z-axis clamping block 815 to ensure uniform distribution of clamping force and prevent workpiece deformation. The connecting block 817 is made of 45 steel, providing sufficient strength and durability; the Z-axis clamping blocks 815 and X-axis clamping blocks 816 are made of beryllium bronze, which has good electrical conductivity and wear resistance, making it suitable for welding environments.

[0029] The rear cover positioning mechanism 8 is also equipped with a linkage device, including a cylinder 821, a linkage block 822, a second limiting block 823, a pin 824, and an adjusting rod 825. The output end of the cylinder 821 is connected to one end of the linkage block 822. The second limiting block 823 is located on one side of the linkage block 822, and the other end of the linkage block 822 is connected to the adjusting rod 825. The adjusting rod 825 is equipped with a pin 824. The adjusting rod 825 includes a first adjusting rod 8251 and a second adjusting rod 8252, which are connected by at least three vertically arranged pins 824. The cylinder 821 drives the first adjusting rod 8251 to move through the linkage block 822, causing the second adjusting rod 8252 to rotate around the pin 824, thereby achieving vertical clamping of the taillight box in the z-direction and ensuring the stability of the workpiece during welding.

[0030] A separate HIP (Hydraulic In-Place) device 10 is installed outside the laser protective room 1. The HIP device 10 is used to supply water and gas required for the welding equipment to operate. The laser protective room 1 is equipped with an entrance door 11 and a roller shutter door 12, which are located on adjacent sides of the laser protective room 1. Both the entrance door 11 and the roller shutter door 12 are used to isolate the laser. The roller shutter door 12 serves as a passage for loading and unloading parts during normal production, while the entrance door 11 serves as a passage for entering and exiting the laser protective room 1 for equipment maintenance during non-production operations, ensuring operational safety.

[0031] The system operates as follows: First, the operator places the workpiece to be processed onto the upper guide device 807 of the rear cover positioning mechanism 8 through the roller shutter door 12. The lifting device 806 descends to position the workpiece. The drive device 802 starts, driving the lamp box clamping device 803, the outer plate support device 804, and the outer plate x-axis clamping device 805 to fix the workpiece. The taillight box clamping unit and the linkage device further clamp the key areas of the workpiece to ensure that the workpiece does not shift during welding. The robot body 7 carries a laser welding gun to perform welding operations. The laser generator 6 provides the laser source, and the test welding station and power meter 9 are used to test and calibrate welding parameters. After welding is completed, the lifting device 806 lifts the workpiece along the rising guide device 807 for easy retrieval.

[0032] Dust removal unit 2 and water chiller 3 respectively handle welding fumes and cooling equipment, while control cabinet 4 and monitoring display system 5 realize automated control and real-time monitoring of the entire system. After welding is completed, roller shutter door 12 serves as the passage for loading and unloading parts during normal production, while entrance door 11 serves as the passage for entering and exiting during non-normal production.

[0033] This system, through precise positioning and clamping mechanisms, effectively avoids porosity defects caused by zinc vapor retention during the welding of galvanized steel sheets, improving weld quality and aesthetics while reducing production costs and rework rates.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fixture and welding system for laser brazing of automotive rear covers, disposed inside and outside a laser protective enclosure (1), characterized in that, include: The dust removal mechanism (2), water chiller (3), control cabinet (4), and monitoring and display system (5) are installed outside the laser protective room (1), while the laser generator (6), robot body (7), rear cover positioning mechanism (8), test welding station, and power meter (9) are installed inside the laser protective room (1); The laser protective room (1) is equipped with a laser source room (101), and the laser generator (6) is installed inside the laser source room (101); The rear cover positioning mechanism (8) and the test welding station and power meter (9) are respectively located on adjacent sides of the robot body (7).

2. The fixture and welding system for laser brazing of automotive rear covers according to claim 1, characterized in that: The rear cover positioning mechanism (8) is equipped with a rear cover laser brazing positioning fixture, which includes a base (801), a drive device (802), a lamp box clamping device (803), an outer plate support device (804), an outer plate x-axis clamping device (805), a lifting device (806), an upper part guide device (807), and a grounding electrode (808). The lifting device (806) is mounted on the base (801), and the lifting device (806) is provided with the upper part guide device (807). The lamp box clamping device (803) is provided at both ends of the lifting device (806). The driving device (802) is mounted on the base (801) and located on the side of the lifting device (806). The outer plate x-direction clamping device (804) is mounted on the base (801) and located at one end of the lifting device (806). The outer plate support device (804) is mounted above the lifting device (806). The grounding electrode (808) is mounted on the base (801) and located on the opposite side of the driving device (802).

3. The fixture and welding system for laser brazing of automotive rear covers according to claim 2, characterized in that: The drive device (802), the lamp box clamping device (803), the outer plate support device (804), the outer plate x-direction clamping device (805), the lifting device (806), and the upper part guide device (807) are all equipped with electric cylinders, which can realize servo adjustable and stepless adjustment of clamping.

4. The fixture and welding system for laser brazing of automotive rear covers according to claim 1, characterized in that: The rear cover positioning mechanism (8) is also provided with a taillight box clamping unit. The taillight box clamping unit is provided with a flip cylinder (811). The output end of the flip cylinder (811) is connected to a connecting rod (812). One end of the connecting rod (812) is provided with a clamping cylinder (813). The bottom of the connecting rod (812) is provided with a limit block (814). The sides of the connecting rod (812) are respectively provided with body z-direction clamping blocks (815). The bottom of the connecting rod (812) is provided with body x-direction clamping blocks (816). The top of the connecting rod (812) is provided with a connecting block (817).

5. A fixture and welding system for laser brazing of automotive rear covers according to claim 4, characterized in that: The vehicle body z-axis clamping block (815) is provided in a plurality of units, and the gap between each vehicle body z-axis clamping block (815) is set to 2mm.

6. A fixture and welding system for laser brazing of automotive rear covers according to claim 5, characterized in that: The connecting block (817) is made of 45 steel, and the body z-direction clamping block (815) and the body x-direction clamping block (816) are made of beryllium bronze.

7. A fixture and welding system for laser brazing of automotive rear covers according to claim 1, characterized in that: The rear cover positioning mechanism (8) is also provided with a linkage device, which includes a cylinder (821), a linkage block (822), a second limiting block (823), a pin (824), and an adjusting rod (825). The output end of the cylinder (821) is connected to one end of the linkage block (822), the second limiting block (823) is located on one side of the linkage block (822), and the other end of the linkage block (822) is connected to the adjusting rod (825). The adjusting rod (825) is provided with the pin (824).

8. A fixture and welding system for laser brazing of automotive rear covers according to claim 7, characterized in that: The adjusting rod (825) includes a first adjusting rod (8251) and a second adjusting rod (8252). The first adjusting rod (8251) and the second adjusting rod (8252) are connected by at least three vertically arranged pins (824). The cylinder (821) can drive the first adjusting rod (8251) to move through the linkage block (822), so that the second adjusting rod (8252) rotates around the pins (824), thereby achieving vertical pressing of the taillight box in the z-direction.

9. A fixture and welding system for laser brazing of automotive rear covers according to claim 1, characterized in that: The laser protective room (1) is also equipped with HIP equipment (10) on the outside. The laser protective room (1) is equipped with an entrance door (11) and a roller shutter door (12). The entrance door (11) and the roller shutter door (12) are located on adjacent sides of the laser protective room (1). The entrance door (11) and the roller shutter door (12) can be used to isolate lasers.

10. A method for applying the fixture and welding system for laser brazing of automotive rear covers as described in any one of claims 1-9, characterized in that, The steps of the method include: S1: Place the workpiece to be processed on the rear cover positioning mechanism (8) through the roller shutter door (12) of the laser protective room (1); S2: The pneumatic lifting device (806) lowers the workpiece to a predetermined position; then the drive device (802) is activated to fix the workpiece through the lamp box clamping device (803), the outer plate support device (804) and the outer plate x-axis clamping device (805); S3: The taillight box clamping unit and the linkage device are used to further clamp the taillight box area of ​​the workpiece. The taillight box clamping unit works in concert with the flipping cylinder (811) and the clamping cylinder (813). The linkage device drives the adjusting rod (825) through the cylinder (821) to achieve vertical clamping of the taillight box in the z direction, ensuring the stability of the workpiece during the welding process. S4: Start the laser generator (6) and the robot body (7). The robot body (7) carries the laser welding gun to perform laser brazing on the workpiece, while the dust removal mechanism (2) handles the welding fumes. S5: After welding is completed, the lifting device (806) rises, which drives the workpiece to rise. Then the workpiece is taken out through the door (11), and the entire welding process is monitored through the monitoring and display system (5).

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