An automatic spot welding robot used in rail transportation

Abstract

The present invention belongs to the technical field of welding robots, and in particular relates to an automatic spot welding robot used in rail transit, comprising a robotic arm, a welding gun mounted on the end of the robotic arm, a mounting hole provided at the bottom end of the welding gun, a protective tube slidably inserted into the mounting hole, a welding assembly provided on the inner side of the protective tube, and the welding assembly comprising a fixed tube, a welding head, a connecting column, a connecting sleeve, a buffer spring, and a limit block. The present invention is provided with a lifting assembly, and during the spot welding process, when the welding head and the protective tube are in contact with the surface of the weldment, the welding head can complete the spot welding operation on the weldment while the weldment pushes it upward, and as the protective tube continues to move upward, the lifting rod can pull the welding head upward and separate from the weldment through the pull rod with the second fixed axis as the center, thereby avoiding the welding head from sticking to the weldment during welding and ensuring the welding quality.

Description

Technical Field

[0001] The present invention belongs to the technical field of welding robots, and in particular relates to an automatic spot welding robot applied to rail transportation. Background Art

[0002] Spot welding is a form of resistance welding. It uses the resistance heat generated when an electric current passes through a welding torch and collides with the workpiece to locally heat the workpiece to a molten state. This heat then forms a weld spot under pressure, thereby achieving a connection. Spot welding technology is widely used in electronics, aerospace, and rail transportation. To improve welding efficiency and quality, an increasing number of spot welding robots have been invented to meet the welding needs of various industries. Spot welding robots are widely used in rail transportation for assembling electrical equipment casings, connecting vehicle body skins to frames, connecting interior partitions to frames, fixing interior decorative panels, and assembling seat frames.

[0003] While existing spot welding robots offer high welding speeds and quality, they still have some practical limitations. For example, when using a robot to spot weld the skin and frame of a rail transit vehicle, the relatively thin skin can become excessively melted when the welding torch collides with the workpiece, causing it to stick to the torch and compromise the weld quality. Summary of the Invention

[0004] In view of the above problems, the present invention provides an automatic spot welding robot applied to rail transportation to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] An automatic spot welding robot used in rail transportation comprises a robotic arm, a welding gun is installed at the end of the robotic arm, a mounting hole is opened at the bottom end of the welding gun, a protective tube is slidably inserted in the mounting hole, a welding assembly is arranged on the inside of the protective tube, the welding assembly comprises a fixed tube, a welding head, a connecting column, a connecting sleeve, a buffer spring, and a limit block, the fixed tube is fixedly inserted on the top inner wall of the mounting hole, the protective tube is slidably sleeved on the outside of the fixed tube, the welding head is slidably inserted at the bottom end of the fixed tube, the connecting column is fixedly connected to the top end of the welding head, the connecting sleeve is slidably sleeved on the top end of the connecting column, and the connecting The sleeve is slidably installed on the inner side of the fixed tube, and the buffer spring is fixedly connected between the top of the connecting column and the inner wall of the top of the connecting sleeve. There are two limit blocks, and the two limit blocks are symmetrically fixedly connected on both sides of the connecting sleeve. Limiting holes are provided on both sides of the fixed tube and the positions opposite to the two limit blocks. An annular groove is provided on the inner wall of the protective tube, and the two limit blocks are respectively inserted into the annular groove through the two limit holes. Two lifting assemblies are symmetrically installed on the top of the connecting sleeve, two reset assemblies are connected between the top of the protective tube and the top of the mounting hole, and a clamping assembly is connected to the top of the connecting sleeve.

[0007] Furthermore, the lifting assembly includes a connecting rod, a lifting rod, a guide shaft, a first fixed shaft, a second fixed shaft, a movable rod, a pull rod and a top block. The first fixed shaft is horizontally penetrated and rotated in the front-to-back direction and is inserted in the top position of the connecting rod, and both ends of the first fixed shaft are fixedly connected to the inner wall of the fixed tube. The lifting rod is hinged at the bottom end of the connecting rod, and the top end of the lifting rod passes through the limiting hole close to it and is located outside the fixed tube. The guide shaft is horizontally and vertically penetrated and inserted in the hinge between the lifting rod and the connecting rod in the front-to-back direction. A groove parallel to its length direction is opened between the front and rear sides of the lifting rod. The movable rod and the second fixed shaft are both horizontally inserted into the strip hole, and the second fixed shaft is closer to the guide shaft than the movable rod. The two ends of the second fixed shaft are respectively fixedly connected to the front and rear inner walls of the limiting hole. There are two pull rods, and the two pull rods are respectively fixedly connected to the two ends of the movable rod. The bottom end of the pull rod is fixedly connected to the top of the connecting sleeve. The top block is fixedly connected to the top of the protective tube. A notch is provided at the top of the top block. Guide holes are provided on the front and rear inner walls of the notch, and the two ends of the guide shaft are respectively slidably inserted into the two guide holes.

[0008] Furthermore, the reset assembly includes a first telescopic rod and a reset spring. The first telescopic rod is fixedly connected between the top of the protective tube and the top of the mounting hole. The reset spring is sleeved on the first telescopic rod. The two ends of the reset spring are respectively fixedly connected to the top of the protective tube and the inner wall of the top of the mounting hole.

[0009] Furthermore, there are two clamping assemblies, and the two clamping assemblies are symmetrically arranged at the front and rear sides of the top of the connecting sleeve. The clamping assembly includes a second telescopic rod and a compression spring. The two ends of the second telescopic rod are respectively fixedly connected to the connecting sleeve and the top inner wall of the fixed tube. The compression spring is sleeved on the second telescopic rod, and the two ends of the compression spring are respectively fixedly connected to the top of the connecting sleeve and the top inner wall of the fixed tube, and the elastic force of the compression spring is greater than the elastic force of the buffer spring.

[0010] Furthermore, a buffer pad is fixedly connected to the bottom end of the protection tube, and in an initial state, the bottom end of the protection tube is lower than the bottom end of the welding head.

[0011] Furthermore, in the initial state, the top of the limit block fits against the top inner wall of the annular groove, and the distance between the bottom of the limit block and the bottom inner wall of the annular groove is equal to the maximum compression of the buffer spring.

[0012] Furthermore, the guide hole includes a vertical section and an inclined section, the vertical section is located at the top of the inclined section, and the bottom end of the inclined section is inclined away from the lifting rod, and the length of the vertical section is equal to the distance between the bottom of the limit block and the inner wall of the bottom of the annular groove in the initial state.

[0013] Furthermore, the bottom end of the welding head is spherical in design, and in an initial state, the distance from the bottom end of the welding head to the bottom end of the protective tube is less than the length of the vertical section of the guide hole.

[0014] Technical effects and advantages of the present invention:

[0015] 1. The present invention is provided with a lifting assembly. During the spot welding process, when the welding head and the protective tube are in contact with the surface of the weldment, the welding head can complete the spot welding operation on the weldment while the weldment pushes it upward. As the protective tube continues to move upward, the lifting rod can pull the welding head upward and separate from the weldment through the pull rod with the second fixed axis as the center, thereby preventing the welding head from sticking to the weldment during welding and ensuring welding quality.

[0016] 2. The present invention is provided with a buffer spring. When the welding head contacts the weldment, the buffer spring can be slightly compressed, thereby converting the force when the welding head collides with the weldment surface into elastic potential energy of the buffer spring, thereby reducing the impact force on the welding head and protecting the welding head from damage. When the lifting rod pulls the welding head upward, the compressed buffer spring can first extend, so that the welding head can remain in close contact with the surface of the weldment in a short time, thereby ensuring that the welding head has sufficient time to weld the weldment and ensure the welding quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0018] Figure 2 It is a three-dimensional schematic diagram of the welding gun, the protective tube and the buffer pad in the present invention;

[0019] Figure 3 is a three-dimensional cross-sectional view of the welding gun of the present invention;

[0020] Figure 4 In the present invention Figure 3 A magnified view of part A;

[0021] Figure 5 It is a three-dimensional schematic diagram of the structures of the protective tube, fixed tube, connecting rod, first telescopic rod and return spring in the present invention;

[0022] Figure 6 is a three-dimensional cross-sectional view of the protective tube and the fixed tube in the present invention;

[0023] Figure 7 In the present invention Figure 6 Enlarged view of part B.

[0024] In the figure: 1. Robotic arm; 2. Welding gun; 3. Protective tube; 4. Fixed tube; 5. Welding head; 6. Connecting column; 7. Connecting sleeve; 8. Buffer spring; 9. Limit block; 10. Limit hole; 11. Annular groove; 12. Connecting rod; 13. Lifting rod; 14. Guide shaft; 15. First fixed shaft; 16. Second fixed shaft; 17. Movable rod; 18. Pull rod; 19. Top block; 20. Guide hole; 21. First telescopic rod; 22. Return spring; 23. Second telescopic rod; 24. Compression spring; 25. Buffer pad. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0026] The present invention provides Figures 1 to 7An automatic spot welding robot for rail transit shown in the figure includes a robotic arm 1, a welding gun 2 is installed at the end of the robotic arm 1, a mounting hole is opened at the bottom end of the welding gun 2, a protective tube 3 is slidably inserted in the mounting hole, a welding assembly is arranged on the inside of the protective tube 3, and the welding assembly includes a fixed tube 4, a welding head 5, a connecting column 6, a connecting sleeve 7, a buffer spring 8, and a limit block 9. The fixed tube 4 is fixedly inserted on the inner wall at the top of the mounting hole, the protective tube 3 is slidably sleeved on the outside of the fixed tube 4, the welding head 5 is slidably inserted at the bottom end of the fixed tube 4, the connecting column 6 is fixedly connected to the top of the welding head 5, the connecting sleeve 7 is slidably sleeved on the top of the connecting column 6, and the connecting sleeve 7 is slidably installed on the inside of the fixed tube 4, and the buffer spring 8 is fixedly connected to the top of the connecting column 6 Between the inner wall of the top of the connecting sleeve 7, there are two limit blocks 9, and the two limit blocks 9 are symmetrically fixedly connected to both sides of the connecting sleeve 7. Limit holes 10 are penetrated at the positions on both sides of the fixed tube 4 opposite to the two limit blocks 9. An annular groove 11 is provided on the inner wall of the protective tube 3, and the two limit blocks 9 pass through the two limit holes 10 and are inserted into the annular groove 11 respectively. Two lifting assemblies are symmetrically installed on the top of the connecting sleeve 7, two reset assemblies are connected between the top of the protective tube 3 and the top of the mounting hole, and a clamping assembly is connected to the top of the connecting sleeve 7. In the initial state, the top of the limit block 9 fits against the top inner wall of the annular groove 11, and the distance between the bottom of the limit block 9 and the bottom inner wall of the annular groove 11 is equal to the maximum compression amount of the buffer spring 8;

[0027] By providing the protection tube 3, the welding head 5 can be located inside the protection tube 3 when not in use, thereby effectively preventing the welding head 5 from being damaged by bumps;

[0028] When in use, as the robotic arm 1 drives the welding gun 2 to approach the surface of the weldment, when the protective tube 3 contacts the surface of the weldment, the protective tube 3 can move upward under the pressure of the weldment. During this process, the reset assembly is compressed, and the welding head 5 can remain stationary under the action of the clamping assembly. As the protective tube 3 continues to move upward, when the bottom end of the welding head 5 contacts the surface of the weldment, the bottom of the annular groove 11 also keeps in contact with the bottom of the limit block 9, and the welding head 5 can move upward together under the action of the supporting force of the inner wall of the bottom of the annular groove 11. During this process, the welding head 5 can keep in contact with the surface of the weldment under the action of the pressure of the buffer spring 8. In the process of the welding head 5 contacting the surface of the weldment, the welding head 5 can be instantly energized, thereby realizing spot welding operation on the weldment. As the protective tube 3 and the welding head 5 continue to move upward, the lifting assembly can pull the welding head 5 upward through the connecting sleeve 7 and the connecting column 6, so that the welding head 5 can be separated from the surface of the weldment, thereby avoiding the welding head 5 from sticking to the surface of the weldment during welding, thereby ensuring the welding quality.

[0029] When the welding head 5 is separated from the workpiece surface by the pulling action of the lifting assembly, the welding head 5 can be in a momentary power-off state, and only after the robotic arm 1 drives the welding gun 2 to completely separate from the workpiece surface, the welding head 5 is powered on, thereby preparing for the next spot welding.

[0030] In addition, by providing a buffer spring 8, when the welding head 5 contacts the surface of the weldment, the buffer spring 8 can be compressed, thereby converting the force when the welding head 5 collides with the surface of the weldment into the elastic potential energy of the buffer spring 8, thereby reducing the impact force on the welding head 5 and protecting the welding head 5 from damage.

[0031] like Figures 3 to 7 As shown, the lifting assembly includes a connecting rod 12, a lifting rod 13, a guide shaft 14, a first fixed shaft 15, a second fixed shaft 16, a movable rod 17, a pull rod 18 and a top block 19. The first fixed shaft 15 is horizontally penetrated and rotated in the front-to-back direction and is inserted in the top position of the connecting rod 12, and both ends of the first fixed shaft 15 are fixedly connected to the inner wall of the fixed tube 4. The lifting rod 13 is hinged to the bottom end of the connecting rod 12, and the top end of the lifting rod 13 passes through the limiting hole 10 close to it and is located outside the fixed tube 4. The guide shaft 14 is horizontally and vertically penetrated and inserted in the hinge between the lifting rod 13 and the connecting rod 12 in the front-to-back direction. A strip hole parallel to its length direction is provided between the front and rear sides of the lifting rod 13. The movable rod 17 and the second fixed shaft 16 are both horizontally penetrated and inserted in the strip hole, and the second fixed shaft 16 is closer to the guide shaft 14 than the movable rod 17. Both ends of the second fixed shaft 16 They are fixedly connected to the front and rear inner walls of the limiting hole 10 respectively. There are two pull rods 18, and the two pull rods 18 are fixedly connected to the two ends of the movable rod 17 respectively. The bottom end of the pull rod 18 is fixedly connected to the top of the connecting sleeve 7. The top block 19 is fixedly connected to the top of the protective tube 3. A notch is provided at the top of the top block 19. Guide holes 20 are provided on the front and rear inner walls of the notch, and the two ends of the guide shaft 14 are slidably inserted into the two guide holes 20 respectively. The guide hole 20 includes a vertical section and an inclined section. The vertical section is located at the top of the inclined section, and the bottom end of the inclined section is inclined in the direction away from the lifting rod 13. The length of the vertical section is equal to the distance between the bottom of the limit block 9 and the bottom inner wall of the annular groove 11 in the initial state. The bottom end of the welding head 5 is spherical in design, and in the initial state, the distance from the bottom end of the welding head 5 to the bottom end of the protective tube 3 is less than the length of the vertical section of the guide hole 20.

[0032] The reset assembly includes a first telescopic rod 21 and a reset spring 22. The first telescopic rod 21 is fixedly connected between the top of the protective tube 3 and the top of the mounting hole. The reset spring 22 is sleeved on the first telescopic rod 21. The two ends of the reset spring 22 are respectively fixedly connected to the top of the protective tube 3 and the inner wall of the top of the mounting hole.

[0033] There are two clamping assemblies, and the two clamping assemblies are symmetrically arranged at the front and rear sides of the top of the connecting sleeve 7. The clamping assembly includes a second telescopic rod 23 and a compression spring 24. The two ends of the second telescopic rod 23 are respectively fixedly connected to the connecting sleeve 7 and the top inner wall of the fixed tube 4. The compression spring 24 is sleeved on the second telescopic rod 23. The two ends of the compression spring 24 are respectively fixedly connected to the top of the connecting sleeve 7 and the top inner wall of the fixed tube 4, and the elastic force of the compression spring 24 is greater than the elastic force of the buffer spring 8.

[0034] By providing a lifting assembly, during electric welding, as the robotic arm 1 drives the welding gun 2 to approach the surface of the weldment, when the protective tube 3 contacts the surface of the weldment, the protective tube 3 can move upward under the pressure of the weldment. During this process, the first telescopic rod 21 and the return spring 22 can be gradually compressed, and the welding head 5 can remain stationary under the pressure of the compression spring 24 on the connecting sleeve 7. At the same time, during the upward movement of the protective tube 3, the guide shaft 14 can first move downward along the vertical section of the guide hole 20, and as the protective tube 3 continues to move upward, when the welding head When the bottom end of 5 contacts the surface of the weldment, the bottom of the annular groove 11 also keeps in contact with the bottom of the limit block 9, the buffer spring 8 is slightly compressed, and the guide shaft 14 also moves to the inclined section of the guide hole 20. At this time, as the robot arm 1 continues to press the welding gun 2, the welding head 5 can move upward together under the support force of the inner wall of the bottom of the annular groove 11. During this process, the welding head 5 can keep in contact with the surface of the weldment under the pressure of the buffer spring 8. In the process of contact between the welding head 5 and the surface of the weldment, the welding head 5 can be instantly energized, thereby realizing the spot welding operation of the weldment;

[0035] As the protective tube 3 and the welding head 5 continue to move upward, the guide shaft 14 can move along the inclined section of the guide hole 20 in the direction away from the connecting sleeve 7, and as the guide shaft 14 moves in the direction away from the connecting sleeve 7, the bottom end of the connecting rod 12 can be deflected upward, and the bottom end of the lifting rod 13 can be deflected upward with the second fixed axis 16 as the center under the action of the pulling force of the connecting rod 12, and as the bottom end of the lifting rod 13 deflects upward, the lifting rod 13 can pull the connecting sleeve 7 upward through the movable rod 17 and the pull rod 18, and in the process of the connecting sleeve 7 moving upward, the buffer spring 8 can be extended first, so that the welding head 5 can keep close to the surface of the weldment in a short time, thereby ensuring that the welding head 5 has sufficient time to weld the weldment, and as the bottom end of the lifting rod 13 continues to deflect upward, when the buffer spring 8 is fully extended, the lifting rod 13 can pull the welding head 5 upward through the movable rod 17 and the pull rod 18, so that the welding head 5 can be separated from the surface of the weldment;

[0036] It should be noted that the above-mentioned welding process is completed in a very short time, so the welding head 5 can be separated from the weldment by the pulling action of the lifting rod 13 at the moment after the welding is completed, thereby avoiding the welding head 5 from sticking to the weldment during welding and ensuring the welding quality.

[0037] like Figures 3 to 6 As shown, the bottom end of the protection tube 3 is fixedly connected with a buffer pad 25, and in the initial state, the bottom end of the protection tube 3 is lower than the bottom end of the welding head 5;

[0038] By providing the buffer pad 25 , when the protection tube 3 contacts the surface of the weldment, the buffer pad 25 can protect the contact position between the protection tube 3 and the surface of the weldment, thereby preventing the surface of the weldment from being damaged due to the collision of the protection tube 3 .

[0039] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same.

Claims

1. An automatic spot welding robot for rail transportation, comprising a robotic arm (1), characterized in that: A welding gun (2) is installed at the end of the robot arm (1), and a mounting hole is opened at the bottom end of the welding gun (2), and a protective tube (3) is slidably inserted in the mounting hole. A welding assembly is arranged on the inner side of the protective tube (3), and the welding assembly includes a fixed tube (4), a welding head (5), a connecting column (6), a connecting sleeve (7), a buffer spring (8), and a limit block (9). The fixed tube (4) is fixedly inserted on the inner wall of the top of the mounting hole, the protective tube (3) is slidably sleeved on the outside of the fixed tube (4), the welding head (5) is slidably inserted at the bottom end of the fixed tube (4), the connecting column (6) is fixedly connected to the top end of the welding head (5), the connecting sleeve (7) is slidably sleeved on the top end of the connecting column (6), and the connecting sleeve (7) is slidably installed on the fixed tube. (4) On the inner side, the buffer spring (8) is fixedly connected between the top of the connecting column (6) and the inner wall of the top of the connecting sleeve (7), the number of the limit blocks (9) is two, and the two limit blocks (9) are symmetrically fixedly connected to both sides of the connecting sleeve (7), and the positions on both sides of the fixed tube (4) facing the two limit blocks (9) are penetrated by limit holes (10), the inner wall of the protective tube (3) is provided with an annular groove (11), and the two limit blocks (9) pass through the two limit holes (10) and are inserted into the annular groove (11), the top of the connecting sleeve (7) is symmetrically installed with two lifting components, the top of the protective tube (3) and the top of the mounting hole are connected with two reset components, and the top of the connecting sleeve (7) is connected with a pressing component; The lifting assembly includes a connecting rod (12), a lifting rod (13), a guide shaft (14), a first fixed shaft (15), a second fixed shaft (16), a movable rod (17), a pull rod (18) and a top block (19), wherein the first fixed shaft (15) is horizontally penetrated and rotated in the front-to-back direction and is inserted into the top position of the connecting rod (12), and both ends of the first fixed shaft (15) are fixedly connected to the inner wall of the fixed tube (4), the lifting rod (13) is hinged to the bottom end of the connecting rod (12), and the top end of the lifting rod (13) passes through the limiting hole (10) close to it and is located outside the fixed tube (4), the guide shaft (14) is horizontally and vertically penetrated and inserted into the hinge of the lifting rod (13) and the connecting rod (12) in the front-to-back direction, and a longitudinal direction is provided between the front and rear sides of the lifting rod (13). The movable rod (17) and the second fixed shaft (16) are both horizontally inserted into the strip hole, and the second fixed shaft (16) is closer to the guide shaft (14) than the movable rod (17). The two ends of the second fixed shaft (16) are respectively fixedly connected to the front and rear inner walls of the limiting hole (10). There are two pull rods (18). The two pull rods (18) are respectively fixedly connected to the two ends of the movable rod (17). The bottom end of the pull rod (18) is fixedly connected to the top of the connecting sleeve (7). The top block (19) is fixedly connected to the top of the protective tube (3). A notch is provided at the top of the top block (19). Guide holes (20) are provided on the front and rear inner walls of the notch, and the two ends of the guide shaft (14) are respectively slidably inserted into the two guide holes (20).

2. The automatic spot welding robot for rail transportation according to claim 1, characterized in that: The reset assembly comprises a first telescopic rod (21) and a reset spring (22), wherein the first telescopic rod (21) is fixedly connected between the top of the protective tube (3) and the top of the mounting hole, and the reset spring (22) is sleeved on the first telescopic rod (21), and the two ends of the reset spring (22) are respectively fixedly connected to the top of the protective tube (3) and the inner wall of the top of the mounting hole.

3. The automatic spot welding robot for rail transportation according to claim 2, characterized in that: There are two clamping assemblies, and the two clamping assemblies are symmetrically arranged at the front and rear sides of the top of the connecting sleeve (7). The clamping assembly includes a second telescopic rod (23) and a clamping spring (24). The two ends of the second telescopic rod (23) are fixedly connected to the connecting sleeve (7) and the top inner wall of the fixed tube (4), respectively. The clamping spring (24) is sleeved on the second telescopic rod (23). The two ends of the clamping spring (24) are fixedly connected to the top of the connecting sleeve (7) and the top inner wall of the fixed tube (4), respectively. The elastic force of the clamping spring (24) is greater than the elastic force of the buffer spring (8).

4. The automatic spot welding robot for rail transportation according to claim 3, characterized in that: The bottom end of the protection tube (3) is fixedly connected to a buffer pad (25), and in an initial state, the bottom end of the protection tube (3) is lower than the bottom end of the welding head (5).

5. The automatic spot welding robot for rail transportation according to claim 4, characterized in that: In the initial state, the top of the limit block (9) fits against the top inner wall of the annular groove (11), and the distance between the bottom of the limit block (9) and the bottom inner wall of the annular groove (11) is equal to the maximum compression of the buffer spring (8).

6. The automatic spot welding robot for rail transportation according to claim 5, characterized in that: The guide hole (20) includes a vertical section and an inclined section, the vertical section is located at the top of the inclined section, and the bottom end of the inclined section is inclined in a direction away from the lifting rod (13), and the length of the vertical section is equal to the distance between the bottom of the limit block (9) and the bottom inner wall of the annular groove (11) in the initial state.

7. The automatic spot welding robot for rail transportation according to claim 6, characterized in that: The bottom end of the welding head (5) is spherical in design, and in an initial state, the distance from the bottom end of the welding head (5) to the bottom end of the protective tube (3) is less than the length of the vertical section of the guide hole (20).

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