Welding robot and welding residual stress monitoring system thereof

Abstract

The invention belongs to the technical field of welding equipment, and particularly relates to a welding robot and a welding residual stress monitoring system thereof.The welding robot comprises a robot body and a welding module installed at the free end of the robot body; the welding module comprises a focusing reflection module fixedly installed on a fixed support, a water cooling outer frame body used for cooling a lens is arranged at the bottom of the focusing reflection module, a coupling reflection lens barrel is installed on one side of the focusing reflection module, and a laser and a thermal imaging temperature monitor are installed on the coupling reflection lens barrel; and butt-joint sections are arranged on the opposite sides of the temperature conducting plates, and the butt-joint sections are oppositely spliced and blocked between the welding workpiece and the preset laser beam to preheat the welding workpiece. The welding position can be preheated and slowly cooled in the welding process, so that generation of prestress and residual stress is effectively reduced, meanwhile, the temperature of a workpiece at the welding position is continuously monitored, and the welding stress state of the workpiece is conveniently monitored.

Description

Technical Field

[0001] The invention belongs to the technical field of welding equipment, and in particular relates to a welding robot and a welding residual stress monitoring system thereof. Background Art

[0002] The laser welding robot uses semiconductor laser as welding heat source, and uses laser beam to locally heat the workpiece to achieve welding automation equipment. Its principle is to use the high energy density of laser to quickly melt and solidify the welding part to form a solid weld. It mainly consists of the following parts: The robot body is the basic component of the laser welding robot and is responsible for the movement and positioning of the robot.

[0003] The laser is the core component of the laser welding robot, responsible for generating a high-energy, highly focused laser beam. The laser beam is transmitted to the workpiece through the focusing reflection module, causing the workpiece to partially melt and solidify, thereby achieving welding.

[0004] The focusing reflection module is a key component on the robot arm, responsible for transmitting the laser beam to the workpiece and adjusting the angle and position of the laser beam.

[0005] The control system is the brain of the laser welding robot, responsible for controlling the robot's movement, the output of the laser, and the position and angle of the focusing reflection module.

[0006] Sensors are the sense organs of laser welding robots, which are used to sense the position, shape, size and other information of the workpiece, as well as parameters such as temperature and pressure during the welding process. The sensors feed this information back to the control system, which adjusts the robot's movement and welding parameters based on this information to ensure welding quality and efficiency.

[0007] However, although the existing laser welding robots are already very advanced, there are still some problems in the actual application process, especially in the control of welding stress: 1. The high temperature characteristics of the welding workpiece and laser welding will cause a lot of prestress and residual stress in the process of laser welding. This welding stress is not well controlled, which reduces the stability of the welding structure at the welding position and may cause cracks or fractures at the welding position.

[0008] 2. In order to protect the welding position, inert gas will be blown to the welding machine position during the welding process to protect it, prevent it from oxidation, and clean up the slag and dust generated by welding. However, the blowing method is generally to blow directly to the welding position. Although it can play a protective role, it only uses inert gas to accelerate the gas flow and does not form an effective protection circle. At the same time, it will accelerate the cooling of the welding position, causing the residual stress to increase. Summary of the invention

[0009] The purpose of the present invention is to provide a welding robot and a welding residual stress monitoring system thereof, which can preheat and slowly cool the welding position during the welding process, thereby effectively reducing the generation of prestress and residual stress, and continuously monitor the workpiece temperature at the welding position in order to monitor the welding stress state of the workpiece.

[0010] The technical solution adopted by the present invention is as follows: A welding robot comprises a robot body and a welding module installed at a free end of the robot body; Wherein, the welding module comprises: A fixed support fixedly connected to the free end of the robot body, an L-shaped support plate being vertically lifted and installed on the fixed support; A focusing reflection module fixedly mounted on the fixed support, wherein a water-cooling outer frame for cooling the lens is provided at the bottom of the focusing reflection module, a coupling reflection lens barrel is installed on one side of the focusing reflection module, and a laser for emitting laser and a thermal imaging temperature monitor for detecting the temperature of the welding workpiece are installed on the coupling reflection lens barrel; A swing support is rotatably mounted on the bottom of the L-shaped support plate, and an L-shaped support arm is slidably mounted on the side of the swing support; A heat conduction plate is fixedly mounted at the bottom of the L-shaped support arm, and a butt cut surface is provided on the opposite side of the heat conduction plate, and the butt cut surface is used to block the welding workpiece and the pre-adjusted laser beam to preheat the welding workpiece. A liquid inlet port and a liquid outlet port are respectively provided at both ends of the heat conduction plate, and a fluid channel connecting the liquid inlet port and the liquid outlet port is provided inside the heat conduction plate, so that the circulating coolant connected to the water-cooled outer frame through the liquid inlet port can slowly cool the welding position through the fluid channel.

[0011] As a preferred solution, a lifting mechanism for driving the L-shaped support plate to vertically lift and lower is arranged between the fixed support and the L-shaped support plate, and includes a first micro servo motor fixedly mounted on the top surface of the fixed support, a first lead screw rotatably mounted on the fixed support, and a first nut slide threadedly connected to the first lead screw. The power output end of the first micro servo motor is connected to the first lead screw through a reducer. A limiting support rod is symmetrically fixedly mounted on the fixed support parallel to the first lead screw. A limiting slide is slidably mounted on the limiting support rod. The L-shaped support plate is fixedly mounted on the first nut slide and the limiting slide.

[0012] As a preferred solution, the L-shaped support plate is provided with a mounting through hole which coincides with the central axis of the lens of the focusing reflective module; a connecting seat is integrally formed on the top surface of the swivel support and is rotatably installed in the mounting through hole; a ring-shaped light source for fill light is fixedly installed at the center of the connecting seat; a turnover mechanism is provided between the connecting seat and the L-shaped support plate for driving the swivel support to rotate circumferentially relative to the L-shaped support plate.

[0013] As a preferred solution, the turnover mechanism includes a second micro servo motor fixedly mounted on the L-shaped support plate, a driving gear connected to the power output end of the second micro servo motor through a reducer, and a driven gear fixedly sleeved on the outer surface of the connecting seat, and the driving gear is meshed with the driven gear.

[0014] As a preferred solution, a third micro servo motor is fixedly installed at the center of the side surface of the swivel support, and the swivel support is symmetrically provided with sliding grooves on both sides of the third micro servo motor. A second nut slide is slidably installed inside the slide groove, and the power output end of the third micro servo motor is connected to a second lead screw through a dual-axis reducer for opposite transmission. The inner side of the second nut slide is threadedly connected to the second lead screw, and the outer side is fixedly connected to the L-shaped support arm.

[0015] As a preferred solution, the butt-joint surface is a vertical butt-joint surface or an inclined butt-joint surface, and the inclination angle is 15°-60°.

[0016] As a preferred solution, a buffer chamber is fixedly installed on one end of the heat conduction plate close to the liquid inlet port, and the buffer chamber is provided with an air inlet port for connecting to blow protective gas. A gas outlet groove perpendicular to it is opened on the butt cut surface, and the gas outlet groove is connected with the buffer chamber to blow protective gas to the welding position.

[0017] As a preferred solution, an air guide component for changing the direction of air flow is installed in the air outlet groove, which includes air guide pipes symmetrically arranged at both ends of the air outlet groove, a V-shaped elastic plate integrally formed between the butt ends of the air guide pipes, and a positioning shaft fixedly installed in the middle of the air outlet groove, a V-shaped groove is formed between the air guide pipe and the V-shaped elastic plate, and the positioning shaft is embedded in the V-shaped groove, and an elastic connecting pipe is arranged between the butt end faces of the air guide pipes for connecting them with each other.

[0018] As a preferred solution, the two oppositely arranged groups of air guide components are both connected to the matching air buffer chamber, and the airflow directions between the two are reversed to form a spiral airflow connected end to end to protect the welding position when deformation occurs.

[0019] A welding residual stress monitoring system for a welding robot, applied to the above-mentioned welding robot, comprises: The stress temperature acquisition module uses a thermal imaging temperature monitor to monitor the initial temperature, preheating temperature, welding temperature and residual temperature at the welding position in real time, and compares and analyzes the collected temperature values ​​with the preset welding stress range; The welding preheating module emits a preheating laser through a laser, a coupled reflective lens barrel and a focusing reflective module, and irradiates the preheating laser onto the temperature conducting plate to preheat the workpiece to be welded in contact with the workpiece, and at the same time adjusts the welding laser power to reach the power required for welding, and uses a thermal imaging temperature monitor to monitor the preheating temperature of the workpiece to be welded until it reaches the required temperature range; The welding stress monitoring module uses a thermal imaging temperature monitor to obtain the actual temperature of the workpiece at the welding position and the temperature value of the welding laser during the welding process, and compares and analyzes the two sets of temperature values ​​collected, and compares and analyzes them with the preset welding temperature rise range to obtain the temperature rise state of the workpiece, and compares and analyzes the temperature rise state with the preset welding stress range to obtain the welding stress state; The welding slow cooling module is connected to the heated circulating coolant of the water-cooled outer frame through the liquid inlet port, and the welding position is kept warm through the fluid channel to achieve the purpose of slow cooling. At the same time, a thermal imaging temperature monitor is used to monitor the temperature value of the welding workpiece during slow cooling, and the temperature value is compared and analyzed with the preset welding stress range to obtain the residual stress state.

[0020] The technical effects achieved by the present invention are: The present invention provides a heat conduction plate and is made of heat conduction material. Before welding the workpiece, the laser that is not fully focused during the welding laser process can be adjusted by the laser to preheat the workpiece in contact with it. At the same time, during the preheating process, the position of the laser lens can be continuously adjusted to control the preheating temperature, ensuring that the laser preheats the workpiece without damaging its surface, thereby reducing welding prestress, ensuring smooth welding, and improving welding quality.

[0021] The present invention cooperates with a liquid inlet port, a liquid outlet port and a fluid channel on the heat conduction plate, and can use the coolant heated after welding to slowly cool the welded part of the welding workpiece during the welding process, reduce its cooling rate, thereby reducing the generation of residual stress, thereby improving the welding quality and avoiding cracks or fractures caused by too fast cooling after welding.

[0022] The present invention arranges an air buffer and an air inlet port on the heat conduction plate, and cooperates with the air guide component. When the heat conduction plates are relatively spliced, the air guide component is hidden in the heat conduction plate. When the air guide pipe is unfolded to weld the workpiece, the air guide pipe is simultaneously unfolded in a V shape under the action of the elastic force of the V-shaped elastic plate, and the two groups of air guide components are relatively arranged to form a diamond-shaped frame to encircle the welding position, and use the staggered relatively flowing airflow to form a swirl airflow to fully surround the welding position for protection, forming a swirl protection layer, so that the welding position is isolated from the outside world, and while avoiding oxidation at the welding position and cleaning the reverse slag and dust, no direct airflow will be formed, which can slow down the temperature drop at the welding position and reduce the generation of residual stress, thereby ensuring the stability of the welding structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram of the three-dimensional structure of an embodiment of the present invention; Figure 2 is a schematic diagram of the three-dimensional structure of a welding module in an embodiment of the present invention; Figure 3 The present invention Figure 2 Exploded diagram of Figure 4 is a schematic diagram of the three-dimensional structure of the other side of the welding module in an embodiment of the present invention; Figure 5 The present invention Figure 3 A partial exploded view of the middle part; Figure 6 2 is a side view of the combination of the swing support and the heat conducting plate in the embodiment of the present invention; Figure 7 1 is a diagram of the unfolded state of the combination of the swing support and the heat conducting plate in the embodiment of the present invention; Figure 8 is another view of the unfolded state of the combination of the swing support and the heat conducting plate in the embodiment of the present invention; Fig. 9 is a schematic diagram of the state change of the gas guide component in an embodiment of the present invention; Fig.10 is a schematic structural diagram of an air guide assembly in an expanded state according to an embodiment of the present invention; Fig.11 The present invention Fig.10 A magnified view of the part in the middle; Fig.12 is a schematic structural diagram of a temperature conducting plate in an embodiment of the present invention; Fig.13 is a cross-sectional view of a thermal conductive plate according to an embodiment of the present invention; Fig.14 Schematic diagram of the structure of the welding residual stress monitoring system in an embodiment of the present invention.

[0024] In the accompanying drawings, the components represented by the reference numerals are listed as follows: 100. Robot body; 200, welding module; 1. Fixed support; 11. L-shaped support plate; 12. first micro servo motor; 13. first lead screw; 14. first nut slide; 15. limit support rod; 16. limit slide; 17. mounting through hole; 18. second micro servo motor; 19. driving gear; 2. Focus reflection module; 21. Water-cooled outer frame; 22. Coupled reflector tube; 23. Thermal imaging temperature monitor; 24. Laser; 25. CCD camera; 3. Swivel support; 31. Connecting seat; 32. L-shaped arm; 33. Ring light source; 34. Driven gear; 35. Third micro servo motor; 36. Dual-axis reducer; 37. Slideway; 38. Second nut slide seat; 39. Second lead screw; 4. Temperature conduction plate; 41. Liquid inlet port; 42. Liquid outlet port; 43. Air buffer chamber; 44. Air inlet port; 45. Butt joint surface; 46. Air outlet groove; 47. Fluid channel; 5. Gas guide assembly; 51. air guide tube; 52. V-shaped elastic plate; 53. positioning shaft; 54. elastic connecting tube. DETAILED DESCRIPTION

[0025] In order to make the purpose and advantages of the present invention more clearly understood, the present invention is specifically described below in conjunction with embodiments. It should be understood that the following text is only used to describe one or several specific embodiments of the present invention, and does not strictly limit the scope of protection of the specific claims of the present invention.

[0026] like Figure 1-Figure 13 As shown, a welding robot includes a robot body 100 and a welding module 200 installed at the free end of the robot body 100.

[0027] See attached Figure 1 In this embodiment, the robot body 100 is a 6-axis articulated manipulator driven by a servo motor, which is composed of a driver, a transmission mechanism, a robot arm, a joint, and an internal sensor. These components work together to ensure that the welding module 200 installed at the free end of the robot arm can accurately reach the specified position, maintain the correct posture, and perform welding operations according to the predetermined motion trajectory.

[0028] Of course, in other embodiments, the robot body 100 can select robot devices with different degrees of freedom as needed to meet production requirements.

[0029] See attached Figure 2-Figure 3 Among them, the welding module 200 includes a fixed support 1 fixedly connected to the free end of the robot body 100, a focusing reflection module 2 fixedly installed on the fixed support 1, a swing support 3 rotatably connected to the fixed support 1, and a heat conduction plate 4 slidably connected to the swing support 3; the fixed support 1 provides stable support for other components, and the swing support 3 can rotate relative to the focusing reflection module 2 to drive the heat conduction plate 4 to follow the welding movement direction, and then the workpiece is preheated, slowly cooled, and protected by air blowing during welding through the heat conduction plate 4.

[0030] See attached Figure 3-Figure 4 A water-cooled outer frame 21 for cooling the lens is provided at the bottom of the focusing and reflecting module 2, and a water inlet and outlet are provided on the water-cooling frame to connect the water-cooling liquid inlet pipe and the liquid outlet pipe, and the welding lens is cooled by circulating water-cooling liquid; at the same time, a coupling reflecting lens barrel 22 is installed on one side of the focusing and reflecting module 2, and a laser 24 for emitting laser is installed on the coupling reflecting lens barrel 22 through a collimating focusing lens, and a thermal imaging temperature monitor 23 for detecting the temperature of the welding workpiece is installed through an inclined bracket, and a CCD camera 25 is installed on the other side of the coupling reflecting lens barrel 22, laser is output through the laser 24, and the collimating focusing lens is used to cooperate with the focusing and reflecting module 2 to focus the output laser beam into a laser spot, and the CCD camera 25 is used to cooperate with the coupling reflecting lens barrel 22 and the focusing and reflecting module 2 to find the welding point, so as to achieve precise welding of the workpiece.

[0031] See attached Figure 5 In order to adjust the distance between the swing support 3 and the lens of the focusing reflection module 2, the top surface of the fixed support 1 includes a first micro servo motor 12 fixedly installed, and a first lead screw 13 is rotatably installed on the fixed support 1, and a first nut slide 14 is threadedly connected to the first lead screw 13. The power output end of the first micro servo motor 12 is connected to the first lead screw 13 through a reducer transmission, and a limit support rod 15 is fixedly installed on the fixed support 1 in parallel and symmetrically with the first lead screw 13, and a limit slide 16 is slidably installed on the limit support rod 15. The L-shaped support plate 11 is fixedly installed using the first nut slide 14 and the limit slide 16. After the adjustment swing support 3 is connected to the L-shaped support plate 11, the first micro servo motor 12 drives the first lead screw 13 to rotate, so that the first nut slide 14 can move up and down along its surface, thereby driving the swing support 3 and the L-shaped support plate 11 to move up and down, thereby realizing the adjustment of the distance between the lens of the focusing reflection module 2.

[0032] Of course, in other embodiments, the distance between the pendulum support 3 and the lens of the focusing reflection module 2 can be adjusted by vertically installing a cylinder or an electric telescopic rod on the fixed support 1, fixing the L-shaped support plate 11 at its power output end, and connecting the adjustable pendulum support 3 to the L-shaped support plate 11. This can be selected according to actual production needs.

[0033] Again refer to the attached Figure 5 In order to enable the swivel support 3 to rotate on the installation plane compared to the L-shaped support plate 11, a mounting through hole 17 that coincides with the central axis of the lens of the focusing and reflecting module 2 is opened on the L-shaped support plate 11. At the same time, a connecting seat 31 is integrally formed on the top surface of the swivel support 3, and is rotatably installed in the mounting through hole 17 using a bearing, so that the laser beam can pass through the mounting through hole 17 and the central axis of the swivel support 3, avoiding obstruction of the laser beam and affecting the welding operation; at the same time, a ring light source 33 for fill light is fixedly installed in the center of the connecting seat 31, so that the ring light source 33 can be adjusted in height compared to the lens of the focusing and reflecting module 2. Due to the setting of the ring structure, the fill light range will not be affected during the rotation process.

[0034] Furthermore, a second micro servo motor 18 is fixedly mounted on the L-shaped support plate 11, and a driving gear 19 is connected to the power output end of the second micro servo motor 18 through a reducer transmission, and a driven gear 34 is fixedly sleeved on the outer surface of the connecting seat 31. By meshing the driving gear 19 with the driven gear 34, the second micro servo motor 18 can be used to drive the driving gear 19 to rotate, thereby driving the swing support 3 to rotate relative to the installation plane of the L-shaped support plate 11.

[0035] Of course, in other embodiments, the purpose of driving the swing support 3 to rotate relative to the installation plane of the L-shaped support plate 11 can be achieved by installing a worm gear transmission between the connecting seat 31 and the installation through hole 17, or other existing annular driving methods can be used.

[0036] See attached Figure 5-Figure 8, an L-shaped support arm 32 is slidably installed on the side of the swing support 3, and the heat conducting plate 4 is fixedly installed at the bottom of the L-shaped support arm 32, so that the two groups of heat conducting plates 4 can move relative to each other to achieve docking and separation, so that before welding, the laser 24, the coupling reflection lens barrel 22 and the focusing reflection module 2 are used to emit a preheating laser, and irradiate the heat conducting plates 4 connected to each other, and at the same time, the heat conducting plate 4 is attached to the surface of the workpiece to be welded to block the welding laser, and the temperature is gradually increased under the action of the welding laser, and the workpiece to be welded that is attached thereto is preheated, and the welding laser power can be adjusted in the process to reach the power required for welding, and in order to The light beam does not damage the heat conducting plate 4. The height of the L-shaped support plate 11 can be adjusted by the first micro servo motor 12 through the first lead screw 13 and the first nut slide 14, and then the distance between the heat conducting plate 4 and the lens of the focusing reflection module 2 can be adjusted, so that the laser beam will not be completely focused on a certain point, that is, the heat conducting plate 4 is heated without damaging its surface; and during the preheating process, the preheating temperature of the workpiece to be welded is monitored by the thermal imaging temperature monitor 23 until the required temperature range is reached, so that the workpiece temperature is adapted to the welding temperature, which can greatly reduce the prestress caused by the welding temperature difference, thereby improving the stability of the welding structure and ensuring the welding quality.

[0037] It should be noted that the heat conduction plate 4 should be made of materials with high thermal conductivity and electrical conductivity, such as copper, aluminum, steel, titanium and their alloy materials, so that it can effectively absorb laser energy and quickly conduct heat, so that it can block the laser beam and conduct heat to preheat the workpiece to be welded. In this embodiment, the heat conduction plate 4 is made of titanium alloy with a melting point of about 1668°C, so that it will not be damaged by the laser when welding general metals. At the same time, its excellent heat resistance and corrosion resistance can be used to ensure the stability of its operation.

[0038] Furthermore, in order to enable the two sets of heat conduction plates 4 to be stably docked, a docking surface 45 is opened on the opposite side of the heat conduction plate 4, and the docking surface 45 is used to relatively splice and block the welding workpiece and the pre-adjusted laser beam to preheat the welding workpiece. The docking surface 45 can be a vertical docking surface or an inclined docking surface. If it is an inclined docking surface, the inclination angle can be set to 15°-60°.

[0039] In this embodiment, the butt-jointed cut surface 45 is a relative 30° inclined angle bevel, so that they can be cross-jointed with each other during butt-jointing, and the butt-jointing is more stable. At the same time, since the butt-jointed gap is not in the center position, the laser beam will not directly irradiate the butt-jointed gap, thereby avoiding damage to the heat conduction plate 4 through the butt-jointed gap, thereby reducing damage to it.

[0040] When the preheating temperature of the workpiece to be welded reaches the required temperature range, the two sets of butt-jointed heat conducting plates 4 need to be separated from each other so that the laser beam can pass through the gap between the two to weld the workpiece. To achieve this purpose: Again refer to the attached Figure 5-Figure 8 The swing support 3 is fixedly installed with a third micro servo motor 35 at the center of its side, and a slide groove 37 is symmetrically opened on both sides of the third micro servo motor 35 on the swing support 3, and a second nut slide 38 is slidably installed inside the slide groove 37. A second lead screw 39 is connected to the power output end of the third micro servo motor 35 through a double-axis reducer 36 for opposite transmission, and the inner side of the second nut slide 38 is threadedly connected to the second lead screw 39, so that the third micro servo motor 35 can synchronously drive the two groups of second lead screws 39 to rotate in opposite directions, so that the two groups of second nut slides 38 are displaced in opposite directions on the second lead screw 39 to separate from or approach each other, and then after the L-shaped support arm 32 is fixedly connected to the outer side of the second nut slide 38, the second lead screw 39 can be driven by the third micro servo motor 35 to rotate to achieve the relative separation and docking of the two groups of heat conduction plates 4.

[0041] Secondly, during the welding process, in order to make the separation gap between the two sets of heat conduction plates 4 parallel to the welding gap, it is necessary to drive the driving gear 19 to rotate through the second micro servo motor 18, and then drive the swing support 3 and the heat conduction plate 4 to rotate compared to the installation plane of the L-shaped support plate 11, so that the separation gap is parallel to the welding gap, so that the welding gap will not be touched during the mobile welding process, so as to avoid scratching the welding gap and causing damage to it.

[0042] See attached Figure 4 as well as Figure 12-13 During the welding process, in order to ensure the stability and consistency of the laser beam, the lens of the focusing reflective module 2 needs to be cooled through the water-cooled outer frame 21. At this time, the coolant needs to be connected through the water inlet of the water-cooled outer frame 21, and after the water-cooled outer frame 21 is circulated and heated, it is discharged from the water outlet of the water-cooled outer frame 21.

[0043] In order to reduce the cooling rate of the weld after welding, a liquid inlet port 41 and a liquid outlet port 42 are respectively provided at both ends of the heat conduction plate 4, and a fluid channel 47 connecting the liquid inlet port 41 and the liquid outlet port 42 is opened inside the heat conduction plate 4, so that the circulating coolant discharged from the water outlet of the water-cooled outer frame 21 is connected through the liquid inlet port 41, and circulates in the heat conduction plate 4 through the fluid channel 47, so as to fit on both sides of the weld for insulation, so that the cooling rate of the welding position is reduced, thereby reducing the generation of residual stress, so as to improve the welding quality and avoid cracks or fractures caused by too fast cooling after welding.

[0044] See attached Figure 9-11In order to protect the welding position by blowing inert gas (generally argon gas) during the welding process, a buffer chamber 43 is fixedly installed on one end of the heat conduction plate 4 close to the liquid inlet port 41, and an air inlet port 44 for connecting the blowing protective gas is arranged on the buffer chamber 43. At the same time, an air outlet groove 46 perpendicular to it is opened on the butt cut surface 45, and the air blowing pipeline is connected through the air inlet port 44. At the same time, the air outlet groove 46 is connected to the buffer chamber 43 through the air channel passing through the heat conduction plate 4 to blow the inert gas to the welding position. After being buffered by the buffer chamber 43, the inert gas is blown onto the welding position through the air outlet groove 46 to protect the welding gap to prevent its oxidation or welding slag dust and other substances from affecting the welding quality.

[0045] In the present embodiment, in order to further improve the protection effect of the weld, an air guide component 5 for changing the air flow direction is installed in the air outlet groove 46, which includes an air guide pipe 51 symmetrically arranged at both ends of the air outlet groove 46, a V-shaped elastic plate 52 integrally formed between the butt ends of the air guide pipe 51, and a positioning shaft 53 fixedly installed in the middle of the air outlet groove 46. A V-shaped groove is formed between the air guide pipe 51 and the V-shaped elastic plate 52, and the positioning shaft 53 is embedded in the V-shaped groove. At the same time, an elastic connecting pipe 54 for connecting the air guide pipe 51 to each other is arranged between the butt end faces. When the two groups of heat conducting plates 4 are butt-jointed with each other, the exposed surfaces of the two groups of air guide components 5 in the opposite combination are also butt-jointed with each other at the same time, so that under the action of the butt thrust, the V-shaped elastic plate 52 and the elastic connecting pipe 54 are unfolded, and then the air guide pipe 51 is stretched to a horizontal state (as shown in the attached figure). Fig. 9 During the welding process, the two sets of heat conducting plates 4 are separated from each other, and the butt thrust disappears. Then, the air guide pipe 51 will be restored to a V-shaped folded state (as shown in the attached figure) under the rebound force of the V-shaped elastic plate 52 and the elastic connecting pipe 54. Fig. 9 right).

[0046] Furthermore, by connecting the two oppositely arranged groups of air guide components 5 to the matching buffer gas chamber 43, and reversing the air flow directions between the two groups (i.e., one group of air guide pipes 51 inputs inert gas from one end close to the buffer gas chamber 43, and the other group of air guide pipes 51 inputs inert gas from one end away from the buffer gas chamber 43, and the two groups are connected to the buffer gas chamber 43 through an elastic hose passing through the heat conduction plate 4, which is not shown in the figure), when the two groups of air guide components 5 are restored to the V-shaped folded state, a diamond-shaped frame can be formed relatively to encircle the welding position, and a spiral airflow can be formed by using the staggered relatively flowing airflow (such as the attached Fig.11The welding position is fully surrounded by a protective swirl layer (shown by the dotted line in the middle), which isolates the welding position from the outside world. While avoiding oxidation at the welding position and cleaning the slag and dust, direct airflow will not be formed, which can slow down the temperature drop at the welding position and reduce the generation of residual stress, thereby ensuring the stability of the welding structure. When deformation occurs, a swirl airflow is formed to protect the welding position.

[0047] Of course, in other embodiments, the gas guide assembly 5 may not be provided, and the inert gas may be directly output through the gas outlet slot 46 to protect the welding position. In actual production, the decision is made according to production requirements.

[0048] The working principle of this embodiment is as follows: first, the position of the welding module 200 is adjusted through the robot body 100 to make it match the position of the workpiece to be welded, and the relatively connected heat conduction plate 4 is attached to the surface of the required welding position of the workpiece to be welded. Then, the preheating laser is emitted through the laser 24, the coupled reflection lens barrel 22 and the focusing reflection module 2, and irradiated on the relatively connected heat conduction plate 4. Under the action of the welding laser, it is gradually heated up, and at the same time, the workpiece to be welded that is attached thereto is preheated to reduce the prestress.

[0049] Secondly, when the preheating temperature of the workpiece reaches a preset range, the third micro servo motor 35 drives the second lead screw 39 to rotate to achieve the relative separation of the two groups of heat conduction plates 4, so that the laser can pass through the gap between the two to weld the workpiece, and at the same time, the second micro servo motor 18 drives the drive gear 19 to rotate, driving the heat conduction plate 4 to rotate so that its separation gap is parallel to the weld so that it will not interfere with it during mobile welding, and at the same time, the liquid inlet port 41 is connected to the circulating coolant discharged from the water outlet of the water-cooled outer frame 21, and circulates in the heat conduction plate 4 through the fluid channel 47, so that it fits on both sides of the weld for insulation, so that the cooling rate of the welding position is reduced, thereby reducing the generation of residual stress.

[0050] Secondly, during the welding process, the blowing pipe can be connected through the air inlet port 44, and the inert gas passes through the buffer chamber 43 and circulates the air flow from the diamond frame formed in the V-shaped folded state, so as to utilize the staggered relative flow of the air flow to form a spiral air flow to fully surround the welding position for protection, forming a swirl protection layer, so that the welding position is isolated from the outside world, and while avoiding oxidation at the welding position and cleaning the slag and dust, direct air blowing will not be formed, which can slow down the temperature drop at the welding position and reduce the generation of residual stress.

[0051] like Figure 1-Figure 14 As shown, a welding residual stress monitoring system for a welding robot is applied to the welding robot in the above embodiment, comprising: The stress temperature acquisition module monitors the initial temperature, preheating temperature, welding temperature and residual temperature at the welding position in real time through a thermal imaging temperature monitor 23, and compares and analyzes the collected temperature values ​​with the preset welding stress range.

[0052] The control system presets the initial temperature range of the workpiece, the temperature difference range during welding, the residual temperature range after welding and the welding stress state, and then the stress state of the workpiece during welding can be judged according to the real-time temperature value obtained, and it can be classified into low stress state, moderate stress state and high stress state.

[0053] The welding preheating module emits a preheating laser through the laser 24, the coupled reflective lens barrel 22 and the focusing reflective module 2, and irradiates the heat conducting plate 4 to preheat the workpiece to be welded that is in contact with it. At the same time, the welding laser power is adjusted to reach the power required for welding, and the thermal imaging temperature monitor 23 is used to monitor the preheating temperature of the workpiece to be welded until the required temperature range is reached (that is, the workpiece reaches a low stress state or a moderate stress state at this time).

[0054] The welding stress monitoring module obtains the actual temperature of the welding position of the workpiece and the temperature value of the welding laser during the welding process through the thermal imaging temperature monitor 23, and compares and analyzes the two sets of temperature values ​​collected, and compares and analyzes them with the preset welding temperature rise range to obtain the temperature rise state of the workpiece (that is, the temperature difference range during the welding process), and compares and analyzes the temperature rise state with the preset welding stress range to obtain the welding stress state (that is, determine whether the weld is in a low stress state, a moderate stress state or a high stress state at this time), and then evaluates the welding quality and structural strength of the weld, which brings convenience to subsequent quality inspection.

[0055] The welding slow cooling module is connected to the heated circulating coolant of the water-cooled outer frame 21 through the liquid inlet port 41, and the welding position is kept warm through the fluid channel 47 to achieve the purpose of slow cooling. At the same time, the thermal imaging temperature monitor 23 is used to monitor the temperature value of the welding workpiece during slow cooling, and the temperature value is compared and analyzed with the preset welding stress range to obtain the residual stress state (that is, it is judged whether the weld is in a low stress state, a moderate stress state or a high stress state at this time).

[0056] Ultimately, the residual stress state and welding stress state can be combined to evaluate the overall welding quality and structural strength of the weld, so that targeted quality inspection can be carried out on welds with poor stress states to determine whether they meet production requirements and whether repair welding and other operations are required, providing a reference for quality inspection work and improving quality inspection efficiency.

[0057] The above is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be considered as the protection scope of the present invention. The structures, devices and operating methods not specifically described and explained in the present invention shall be implemented according to the conventional means in the art unless otherwise specified and limited.

Claims

1. A welding robot, comprising a robot body (100), characterized in that: A welding module (200) installed at the free end of the robot body (100); Wherein, the welding module (200) comprises: A fixed support (1) fixedly connected to the free end of the robot body (100), an L-shaped support plate (11) being vertically mounted on the fixed support (1); A focusing reflection module (2) fixedly mounted on the fixed support (1), wherein a water-cooling outer frame (21) for cooling a lens is provided at the bottom of the focusing reflection module (2), a coupling reflection lens barrel (22) is mounted on one side of the focusing reflection module (2), and a laser (24) for emitting laser light and a thermal imaging temperature monitor (23) for detecting the temperature of a welding workpiece are mounted on the coupling reflection lens barrel (22); A swivel support (3) rotatably mounted on the bottom of the L-shaped support plate (11), wherein L-shaped support arms (32) are slidably mounted on opposite sides of the swivel support (3); A heat conduction plate (4) is fixedly mounted on the bottom of the L-shaped support arm (32), wherein a butt cut surface (45) is provided on one opposite side of the heat conduction plate (4), and the butt cut surface (45) is used to block the welding workpiece and the pre-adjusted laser beam to preheat the welding workpiece, and a liquid inlet port (41) and a liquid outlet port (42) are provided at both ends of the heat conduction plate (4), and a fluid channel (47) connecting the liquid inlet port (41) and the liquid outlet port (42) is provided inside the heat conduction plate (4), so that the circulating coolant connected to the water-cooled outer frame (21) through the liquid inlet port (41) passes through the fluid channel (47) to slowly cool the welding position.

2. A welding robot according to claim 1, characterized in that: A lifting mechanism for driving the L-shaped support plate (11) to vertically lift is provided between the fixed support (1) and the L-shaped support plate (11), comprising a first micro servo motor (12) fixedly mounted on the top surface of the fixed support (1), a first lead screw (13) rotatably mounted on the fixed support (1), and a first nut slide (14) threadedly connected to the first lead screw (13); a power output end of the first micro servo motor (12) is transmission-connected to the first lead screw (13) via a reducer; a limit support rod (15) is fixedly mounted on the fixed support (1) in parallel and symmetrically with the first lead screw (13); a limit slide (16) is slidably mounted on the limit support rod (15); and the L-shaped support plate (11) is fixedly mounted on the first nut slide (14) and the limit slide (16).

3. A welding robot according to claim 1, characterized in that: The L-shaped support plate (11) is provided with a mounting through hole (17) which coincides with the central axis of the lens of the focusing reflective module (2); a connecting seat (31) is integrally formed on the top surface of the rotary pendulum support (3) and is rotatably mounted in the mounting through hole (17); a ring-shaped light source (33) for fill light is fixedly mounted at the center of the connecting seat (31); and a rotating mechanism is provided between the connecting seat (31) and the L-shaped support plate (11) for driving the rotary pendulum support (3) to rotate in a circumferential direction relative to the L-shaped support plate (11).

4. A welding robot according to claim 3, characterized in that: The turnover mechanism comprises a second micro servo motor (18) fixedly mounted on the L-shaped support plate (11), a driving gear (19) drivingly connected to a power output end of the second micro servo motor (18) via a reducer, and a driven gear (34) fixedly sleeved on an outer surface of the connecting seat (31), the driving gear (19) meshing with the driven gear (34).

5. A welding robot according to claim 1, characterized in that: A third micro servo motor (35) is fixedly mounted at the center of the side of the swing support (3); the swing support (3) is symmetrically provided with slide grooves (37) on both sides of the third micro servo motor (35); a second nut slide (38) is slidably mounted inside the slide groove (37); a power output end of the third micro servo motor (35) is connected to a second lead screw (39) in opposite directions through a dual-axis reducer (36); the inner side of the second nut slide (38) is threadedly connected to the second lead screw (39), and the outer side is fixedly connected to the L-shaped support arm (32).

6. A welding robot according to claim 1, characterized in that: The butt-jointed cut surface (45) is a vertical butt-jointed surface or an inclined butt-jointed surface, and the inclination angle is 15°-60°.

7. A welding robot according to claim 1, characterized in that: A buffer chamber (43) is fixedly mounted on one end of the heat conducting plate (4) close to the liquid inlet port (41); the buffer chamber (43) is provided with an inlet port (44) for connecting to blow a protective gas; the butt cut surface (45) is provided with a gas outlet groove (46) perpendicular thereto; the gas outlet groove (46) is connected to the buffer chamber (43) to blow the protective gas to the welding position.

8. A welding robot according to claim 7, characterized in that: An air guide assembly (5) for changing the direction of air flow is installed in the air outlet groove (46), comprising an air guide tube (51) symmetrically arranged at both ends of the air outlet groove (46), a V-shaped elastic plate (52) integrally formed between the butt ends of the air guide tube (51), and a positioning shaft (53) fixedly installed in the middle of the air outlet groove (46), a V-shaped groove is formed between the air guide tube (51) and the V-shaped elastic plate (52), and the positioning shaft (53) is embedded in the V-shaped groove, and an elastic connecting tube (54) for connecting the butt end surfaces of the air guide tube (51) is arranged between them.

9. A welding robot according to claim 8, characterized in that: The two groups of air guide components (5) arranged opposite to each other are both connected to the matching air buffer chamber (43), and the airflow directions between the two are reversed so as to form a spiral airflow connected end to end to protect the welding position when deformation occurs.

10. A welding residual stress monitoring system for a welding robot, applied to the welding robot according to any one of claims 1 to 9, characterized in that: include: A stress temperature acquisition module, which uses a thermal imaging temperature monitor (23) to monitor the initial temperature, preheating temperature, welding temperature and residual temperature at the welding position in real time, and compares and analyzes the collected temperature values ​​with a preset welding stress range; A welding preheating module, which emits a preheating laser through a laser (24), a coupled reflective lens barrel (22) and a focusing reflective module (2), and irradiates the preheating laser onto a heat conducting plate (4) to preheat a workpiece to be welded that is in contact with the heat conducting plate (4), and at the same time adjusts the welding laser power to reach the power required for welding, and uses a thermal imaging temperature monitor (23) to monitor the preheating temperature of the workpiece to be welded until the required temperature range is reached; The welding stress monitoring module acquires the actual temperature of the welding position of the workpiece and the temperature value of the welding laser during the welding process through a thermal imaging temperature monitor (23), compares and analyzes the two sets of temperature values ​​acquired, and compares and analyzes them with the preset welding temperature rise range to obtain the temperature rise state of the workpiece, and compares and analyzes the temperature rise state with the preset welding stress range to obtain the welding stress state; The welding slow cooling module is connected to the heated circulating coolant of the water-cooled outer frame (21) through the liquid inlet port (41), and the welding position is kept warm through the fluid channel (47) to achieve the purpose of slow cooling. At the same time, a thermal imaging temperature monitor (23) is used to monitor the temperature value of the welding workpiece during slow cooling, and a comparison analysis is performed based on the temperature value and the preset welding stress range to obtain the residual stress state.

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