A magnetic synchronous walking type inert gas protection titanium alloy pipe welding robot

Abstract

The application discloses a magnetic-synchronous walking type inert gas protection titanium alloy pipe welding robot, which comprises titanium alloy pipes to be welded, a driving type welding robot, a following type inert gas protection robot and a mechanical arm; after two titanium alloy pipes to be welded are coaxially spliced, a circle of welds to be welded is formed at the splicing position; the driving type welding robot walks and adheres to the outer wall surface of the titanium alloy pipe to be welded under the connection of the mechanical arm; the following type inert gas protection robot walks and adheres to the inner wall surface of the titanium alloy pipe to be welded; the following type inert gas protection robot is magnetically attracted to the driving type welding robot through a magnetic attraction device; and the following type inert gas protection robot follows the driving type welding robot under the action of the magnetic force; thus, the equipment can realize non-oxidation in the welding area in the invisible pipeline.

Description

Technical Field

[0001] This invention belongs to the field of titanium alloy pipe welding robots. Background Technology

[0002] Magnetron welding technology for titanium alloy pipes achieves synchronous movement of two carriages inside and outside the pipe through magnetic coupling. The core technology utilizes the attractive force of internal and external magnets to achieve contactless linkage between the outer carriage (B) and the inner carriage (A). The inner carriage (A) carries an inert gas protective shield that precisely covers the inner wall of the weld; the outer carriage (B) carries the welding device. Both move synchronously under magnetic force, ensuring that the inner and outer sides of the weld are continuously protected by an inert gas such as argon during the welding process, preventing high-temperature oxidation of the titanium alloy. This technology primarily addresses the problems of insufficient internal protection and back-side oxidation in traditional titanium alloy pipe welding. Current technical limitations include:

[0003] 1. When magnetically attached follow-up robots walk on the inner wall of pipes, their motion accuracy and stability are far lower than those of active robots outside the pipes. Furthermore, because the inner wall of the pipe is not visible, it is very easy for them to get stuck by microscopic unevenness of the pipe wall (such as weld excess height and scratches), which can easily cause motion interference.

[0004] 2. The gas protection effect is difficult to guarantee. If the gap between the inner protective cover and the pipe wall is too small (≤2mm), it is easy to get stuck due to the bulging or deformation of the inner wall of the pipe during the movement. If the gap is too large (>5mm), the inert gas cannot maintain positive pressure, and oxygen will seep in and cause oxidation of the titanium alloy weld. Summary of the Invention

[0005] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the present invention provides a magnetically attracted synchronous walking inert gas protected titanium alloy pipe welding robot, which enables the equipment to achieve oxidation-free welding zone in the invisible pipe.

[0006] Technical solution: To achieve the above objectives, the present invention provides a magnetically attracted synchronous walking inert gas protected titanium alloy tube welding robot, comprising a titanium alloy tube to be welded, an active welding robot, a follow-up inert gas protected robot, and a robotic arm; after two titanium alloy tubes to be welded are coaxially spliced ​​together, a ring of weld seam is formed at the splice.

[0007] The active welding robot moves and attaches to the outer wall of the titanium alloy pipe to be welded, connected to a robotic arm. The follower inert gas protection robot moves and attaches to the inner wall of the titanium alloy pipe to be welded. The follower inert gas protection robot is magnetically attracted to the active welding robot through a magnetic attraction device. Under the action of magnetic force, the follower inert gas protection robot follows the active welding robot.

[0008] Furthermore, the active welding robot includes a walking frame and a welding machine; the walking frame is fixed at the end of the robotic arm, and the four-way wheels rotatably mounted around the walking frame roll tangentially to the outer circumference of the titanium alloy pipe to be welded; a welding machine base is fixedly mounted on the back of the walking frame, and the welding machine is fixedly mounted on the welding machine base through a welding machine bracket; the end of the welding gun of the welding machine corresponds to the seam to be welded.

[0009] Furthermore, a variable magnetic attraction electromagnet unit is fixedly installed on the side of the walking frame near the titanium alloy tube to be welded. The magnetic field generated by the variable magnetic attraction electromagnet unit passes through the wall of the titanium alloy tube to be welded and generates a magnetic attraction force on the follow-up inert gas protection robot.

[0010] Furthermore, the follow-up inert gas protection robot includes a B-type walking frame, a permanent magnet unit, and an arc-shaped B-type protective cover; the B-type four-way wheels, which are rotatably mounted around the B-type walking frame, roll tangentially with the inner wall surface of the titanium alloy pipe to be welded, and the permanent magnet unit is located on the side of the B-type walking frame close to the wall of the titanium alloy pipe to be welded.

[0011] Furthermore, the permanent magnet unit has guide posts vertically fixed on its back side in a rectangular array, and ball bearing guide sleeves are arranged in a rectangular array on the b-type traveling frame. Each guide post guides and cooperates with each ball bearing guide sleeve. The side of the b-type traveling frame closest to the permanent magnet unit is connected to the back side of the permanent magnet unit by several tension springs. The variable magnetic attraction electromagnet unit and the permanent magnet unit are magnetically attracted to each other. Under the pull of several tension springs, the permanent magnet unit always maintains a distance from the inner wall of the titanium alloy tube to be welded. The greater the magnetic attraction force applied by the variable magnetic attraction electromagnet unit, the closer the permanent magnet unit will be to the inner wall of the titanium alloy tube to be welded, and the greater the extension length of the tension spring.

[0012] Furthermore, two a-arms extending radially along the titanium alloy tube to be welded are fixedly connected to both sides of the back of the permanent magnet unit. Each a-arm is integrally connected to a bearing seat at its end, and the unit also includes a swing arm shaft that rotates with the bearing seat through the bearing. Two arc support plates are symmetrically arranged on both sides of the permanent magnet unit, and the outer arc radius of the arc support plate is consistent with the inner wall radius of the titanium alloy tube to be welded.

[0013] Both circular arc support plates have an integrally connected b-arm extending radially along the titanium alloy tube to be welded on their concave sides. The ends of the two b-arms away from the circular arc support plates are respectively fixedly connected to the two ends of the arm shaft. The two sides of each b-arm near the circular arc support plate are symmetrically connected to transverse return springs. The ends of each transverse return spring away from the b-arm are fixedly connected to the b-walking frame through return spring brackets. In the initial state, the b-arms are basically parallel to the a-arm under the pull and reset of several transverse return springs.

[0014] The arc-shaped b protective cover is fixedly connected to the b swing arm via a connecting arm. Inside the arc-shaped b protective cover is an arc-shaped b inert gas protection chamber with its opening facing the inner wall of the titanium alloy tube to be welded. The end face of the arc-shaped b protective cover near the inner wall of the titanium alloy tube to be welded is an arc surface with the same inner diameter as the inner wall of the titanium alloy tube to be welded. It also includes an inert gas flexible supply hose, and the inert gas outlet end of the inert gas flexible supply hose is connected to the b inert gas protection chamber.

[0015] Furthermore, the variable magnetic attraction electromagnet unit includes a position and a position. In position a, the magnetic force applied by the variable magnetic attraction electromagnet unit to the permanent magnet unit is F1. In position b, the magnetic force applied by the variable magnetic attraction electromagnet unit to the permanent magnet unit is F2; ​​F1 < F2.

[0016] In position B, the permanent magnet unit overcomes the tension of the tension spring under the magnetic attraction of the variable magnetic attraction electromagnet unit, causing the permanent magnet unit to move closer to the inner wall of the titanium alloy tube to be welded, until the convex arc surfaces of the two arc support plates support and adhere to the inner wall of the titanium alloy tube to be welded, thus forming a balance. In this state, the tension of the tension spring and the supporting force of the inner wall of the titanium alloy tube to be welded against the two arc support plates together counteract the magnetic force on the permanent magnet unit, which is F2. In position B, the two arc support plates are tightly attached to the inner wall of the titanium alloy tube to be welded, so that the swing arm shaft is just coaxial with the titanium alloy tube to be welded. At this time, the arc surface gap of the arc-shaped B protective cover fits the inner wall of the titanium alloy tube to be welded. In this state, if inert gas is continuously injected into the B inert gas protection chamber, the inert gas entering the B inert gas protection chamber can only leak through the narrow gap between the arc surface and the inner wall of the titanium alloy tube to be welded, so that the B inert gas protection chamber can maintain a relatively positive pressure state.

[0017] In position A, due to the relatively smaller magnetic attraction force on the permanent magnet unit, the permanent magnet unit, under the strong pulling force of the four tension springs, is further away from the inner wall of the titanium alloy tube to be welded compared to position B. This causes the two arc-shaped support plates and the arc-shaped b-shaped protective cover to be further away from the inner wall of the titanium alloy tube to be welded, making the two arc-shaped support plates and the arc-shaped b-shaped protective cover further away from and separated from the inner wall of the titanium alloy tube to be welded. In this state, the tension of the tension springs alone counteracts the magnetic force on the permanent magnet unit, which is F1.

[0018] Furthermore, the total weight G of the follow-up inert gas protected robot is 10×G<F1.

[0019] Furthermore, a working method for a magnetically attracted synchronous walking inert gas protected titanium alloy pipe welding robot.

[0020] Step 1: The active welding robot reaches the predetermined position on the inner wall of the titanium alloy pipe to be welded, in gear A.

[0021] Step 2: Enter gear B. In gear B, continuously inject inert gas into the inert gas protection chamber.

[0022] Step 3: Based on the b setting, control the welding torch to perform spray welding on the corresponding weld seam. At the same time, control the robotic arm to slowly rotate the entire active welding robot around the axis of the titanium alloy pipe to be welded by a°. The welding torch slowly welds a small section of the weld seam along the corresponding weld seam path and then pauses.

[0023] Step four: While maintaining the B gear, wait for a while.

[0024] Step 5: Shift to gear A. In gear A, the swing arm B will automatically reset under the restoring force of the lateral return spring.

[0025] Repeat step two through step five 360 ​​times.

[0026] Beneficial Effects: This invention solves the industry challenge of simultaneously achieving "motion stability of the follow-up robot" and "inert gas sealing" in titanium alloy pipe welding through an innovative combination of variable magnetic attraction levels and an adaptive mechanical structure. Its step-by-step welding process further ensures that the weld seam is under double-sided gas protection throughout the entire process, significantly improving the welding quality and reliability of titanium alloys. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of this solution;

[0028] Figure 2 This is an overall sectional view of the plan;

[0029] Figure 3 This is a schematic diagram of a follow-up inert gas protected robot.

[0030] Figure 4 for Figure 3 An enlarged view of the mark at 80;

[0031] Figure 5 for Figure 4 A cross-sectional view from another perspective;

[0032] Figure 6 for Figure 2 The above is a partial sectional view. Detailed Implementation

[0033] The invention will now be further described with reference to the accompanying drawings.

[0034] As attached Figures 1 to 6 The image shows a magnetically attracted, synchronously walking, inert gas-protected titanium alloy pipe welding robot, such as... Figure 1 and 2As shown, it includes a titanium alloy tube to be welded 3, an active welding robot 5, a follow-up inert gas protected robot 6, and a robotic arm 1; after two titanium alloy tubes to be welded 3 are coaxially spliced, a ring of weld seam 2 is formed at the splice, and the titanium alloy tubes to be welded 3 are installed on the fixture equipment.

[0035] The active welding robot 5 moves and attaches to the outer wall of the titanium alloy pipe 3 to be welded under the connection of the robotic arm 1. The follow-up inert gas protection robot 6 moves and attaches to the inner wall of the titanium alloy pipe 3 to be welded. The follow-up inert gas protection robot 6 is magnetically attracted to the active welding robot 5 through a magnetic attraction device. The follow-up inert gas protection robot 6 follows the active welding robot 5 under the action of magnetic force.

[0036] The active welding robot 5 includes a walking frame 15, a welding machine 19, and a protective cover 21. The walking frame 15 is fixed to the end of the robotic arm 1, and the four-way wheels 14 rotatably mounted around the walking frame 15 roll tangentially with the outer circumferential surface of the titanium alloy pipe 3 to be welded. A welding machine base 17 is fixedly mounted on the back of the walking frame 15, and the welding machine 19 is fixedly mounted on the welding machine base 17 through a welding machine bracket 18. The end of the welding torch 51 of the welding machine 19 corresponds to the weld seam 2 to be welded. The protective cover 21 is fixedly connected to the welding machine bracket 18, and the protective cover 21 is clearance-fitted with the outer circumferential surface of the titanium alloy pipe 3 to be welded. Inside the protective cover 21 is an inert gas protective chamber 39, which covers the area outside the weld seam 2 corresponding to the end of the welding torch 51. It also includes an inert gas spray gun 52 that extends into the inert gas protective chamber 39.

[0037] A variable magnetic attraction electromagnet unit 16 is fixedly installed on one side of the walking frame 15 near the titanium alloy tube 3 to be welded. The magnetic field generated by the variable magnetic attraction electromagnet unit 16 passes through the wall of the titanium alloy tube 3 to be welded and generates magnetic attraction force on the follow-up inert gas protection robot 6.

[0038] like Figures 3 to 6 As shown, the follow-up inert gas protection robot 6 includes a walking frame 12, a permanent magnet unit 11, and an arc-shaped protective cover 7. The four-way wheels 13 rotatably mounted around the walking frame 12 roll tangentially with the inner wall surface of the titanium alloy tube to be welded 3, so that the distance between the walking frame 12 and the inner wall surface of the titanium alloy tube to be welded 3 remains constant.

[0039] The permanent magnet unit 11 is located on the side of the b-walking frame 12 near the wall of the titanium alloy pipe 3 to be welded. Four guide posts 27 arranged in a rectangular array are vertically fixed on the back side of the permanent magnet unit 11. Four ball guide sleeves 26 are arranged in a rectangular array on the b-walking frame 12. The four guide posts 27 guide and cooperate with the four ball guide sleeves 26 respectively. The side of the b-walking frame 12 near the permanent magnet unit 11 is connected to the back side of the permanent magnet unit 11 by several tension springs 25.

[0040] The variable magnetic attraction electromagnet unit 16 and the permanent magnet unit 11 are magnetically attracted to each other. Under the pull of several tension springs 25, the permanent magnet unit 11 always maintains a distance from the inner wall surface of the titanium alloy tube 3 to be welded. The greater the magnetic attraction force applied by the variable magnetic attraction electromagnet unit 16, the closer the permanent magnet unit 11 will be to the inner wall surface of the titanium alloy tube 3 to be welded, and the greater the extension length of the tension springs 25. Two swing arms 9 extending radially along the titanium alloy tube 3 are fixedly connected to the back sides of the permanent magnet unit 11. The ends of the two swing arms 9 are integrally connected to the bearing seats 60, and the swing arm shafts 8 are also included, which rotate and cooperate with the bearing seats 60 through the bearings. Two arc support plates 2 are symmetrically arranged on the left and right sides of the permanent magnet unit 11. 8. The outer arc radius of the arc support plate 28 is consistent with the inner wall radius of the titanium alloy tube 3 to be welded; a b-swing arm 10 extending radially along the titanium alloy tube 3 is integrally connected to the concave side of each of the two arc support plates 28. The ends of the two b-swing arms 10 away from the arc support plate 28 are respectively fixedly connected to the two ends of the swing arm shaft 8; lateral return springs 23 are symmetrically connected to the two sides of the end of each b-swing arm 10 near the arc support plate 28. The end of each lateral return spring 23 away from the b-swing arm 10 is fixedly connected to the b-walking frame 12 through the return spring bracket 24. In the initial state, the b-swing arm 10 is basically parallel to the a-swing arm 9 under the pull and reset of several lateral return springs 23.

[0041] The arc-shaped protective cover 7 is fixedly connected to the swing arm 10 via the connecting arm 41. Inside the arc-shaped protective cover 7 is an arc-shaped inert gas protection chamber 31 with its opening facing the inner wall of the titanium alloy tube 3 to be welded. The end face of the arc-shaped protective cover 7 near the inner wall of the titanium alloy tube 3 to be welded is an arc surface 32 that matches the inner diameter of the inner wall of the titanium alloy tube 3 to be welded. It also includes an inert gas flexible supply hose 4, and the inert gas outlet end of the inert gas flexible supply hose 4 is connected to the inert gas protection chamber 31.

[0042] The variable magnetic attraction electromagnet unit 16 includes positions a and b. In position a, the magnetic force applied by the variable magnetic attraction electromagnet unit 16 to the permanent magnet unit 11 is F1. In position b, the magnetic force applied by the variable magnetic attraction electromagnet unit 16 to the permanent magnet unit 11 is F2; ​​F1 < F2. The follow-up inert gas protection robot 6 of this solution adopts a lightweight material design, such as a lightweight carbon fiber structure. The total weight G of the follow-up inert gas protection robot 6 is much smaller than the magnetic force F1 applied by the variable magnetic attraction electromagnet unit 16 to the permanent magnet unit 11, specifically at least 10 × G < F1. Therefore, regardless of the posture of the follow-up inert gas protection robot 6, the influence of gravity on the tension spring 25 and the return spring 23 in this device is very small and negligible. The total weight G ≤ 3kg (F1 ≥ 300N), and the influence of gravity on the springs is < 5%, ensuring that the function remains unchanged when welding inverted.

[0043] In gear B, due to the greater magnetic attraction force on the permanent magnet unit 11, the permanent magnet unit 11 overcomes the tension force of the tension spring 25 under the strong magnetic attraction of the variable magnetic attraction electromagnet unit 16, causing the permanent magnet unit 11 to move closer to the inner wall surface of the titanium alloy tube 3 to be welded, until the convex arc surfaces of the two arc support plates 28 support and adhere to the inner wall surface of the titanium alloy tube 3 to be welded, thus forming a balance. In this state, the tension force of the tension spring 25 and the supporting force of the inner wall surface of the titanium alloy tube 3 to be welded against the two arc support plates 28 together counteract the magnetic force on the permanent magnet unit 11, which is F2. The supporting force of the inner wall surface of the titanium alloy tube 3 to be welded against the two arc support plates 28 is at least half the size of F2. In position b, the two arc-shaped support plates 28 are tightly fitted to the inner wall of the titanium alloy tube to be welded 3, so that the swing arm shaft 8 is exactly coaxial with the titanium alloy tube to be welded 3. At this time, the arc surface 32 of the arc-shaped b protective cover 7 is fitted with the inner wall of the titanium alloy tube to be welded 3 with a gap of less than 2mm. In this state, if inert gas is continuously injected into the b inert gas protection chamber 31, the inert gas entering the b inert gas protection chamber 31 can only leak through the narrow gap between the arc surface 32 and the inner wall of the titanium alloy tube to be welded 3, so that the b inert gas protection chamber 31 can maintain a relatively positive pressure state, thereby preventing external oxygen from flowing into the b inert gas protection chamber 31.

[0044] In position A, due to the relatively smaller magnetic attraction force on the permanent magnet unit 11, under the strong pulling force of the four tension springs 25, the permanent magnet unit 11 is further away from the inner wall of the titanium alloy tube to be welded 3 compared to position B. This causes the two arc-shaped support plates 28 and the arc-shaped b protective cover 7 to be further away from the inner wall of the titanium alloy tube to be welded 3, making the two arc-shaped support plates 28 and the arc-shaped b protective cover 7 further away from and separated from the inner wall of the titanium alloy tube to be welded 3. In this state, the tension of the tension spring 25 alone counteracts the magnetic force on the permanent magnet unit 11, which is F1.

[0045] The working method and principle of this invention:

[0046] Step 1: In the initial state, the active welding robot 5, driven by the robotic arm 1, attaches to the outer wall of the titanium alloy tube 3 to be welded, and aligns the end of the welding torch 51 with the weld seam 2. At this time, the protective cover 21 is placed on the outer area of ​​the weld seam 2 corresponding to the end of the welding torch 51. Simultaneously, the follow-up inert gas protection robot 6, in position a, follows the active welding robot 5 to the predetermined position on the inner wall of the titanium alloy tube 3 under the action of magnetic force, so that the inert gas protection chamber 31 of the arc-shaped protective cover 7 is placed on the inner area of ​​the weld seam 2 corresponding to the end of the welding torch 51. At this time, since it is position a, the arc surface 32 of the arc-shaped protective cover 7 is more than 5mm away from the inner wall of the titanium alloy tube 3 to be welded. At this time, if the inert gas injected into the inert gas protection chamber 31 is easily escaped, it is difficult to maintain positive pressure.

[0047] The purpose of entering gear A: In gear A, the two arc-shaped support plates 28 and the arc-shaped protective cover 7 are further away from and separated from the inner wall of the titanium alloy tube to be welded 3, with a separation distance greater than 6mm, completely avoiding walking interference. Only the four four-way wheels 13 are tangentially rolling with the inner wall of the titanium alloy tube to be welded 3. In this state, the follow-up inert gas protective robot 6, under the action of magnetic force, follows the active welding robot 5 along the inner wall of the titanium alloy tube to be welded 3. During this process, it will not cause movement interference due to slight protrusions and slight deformations of the inner wall of the titanium alloy tube to be welded 3, micro-unevenness of the tube wall such as weld excess height, scratches, etc.

[0048] Step two: Control the variable magnetic attraction electromagnet unit 16 of the active welding robot 5 to enter position b. In position b, the permanent magnet unit 11 experiences a greater magnetic attraction. Under the strong magnetic attraction of the variable magnetic attraction electromagnet unit 16, the permanent magnet unit 11 overcomes the tension of the tension spring 25, causing the permanent magnet unit 11 to move closer to the inner wall surface of the titanium alloy tube 3 to be welded, until the convex arc surfaces of the two arc support plates 28 support and adhere to the inner wall surface of the titanium alloy tube 3 to be welded, forming a balance. In this state, the tension of the tension spring 25 and the supporting force of the inner wall surface of the titanium alloy tube 3 to be welded against the two arc support plates 28 together counteract the magnetic force F2 experienced by the permanent magnet unit 11. The supporting force of the inner wall surface of the titanium alloy tube 3 to be welded against the two arc support plates 28 is at least half the size of F2. In position b, because the two arc support plates 28 are tightly attached... The inner wall of the titanium alloy tube 3 to be welded is aligned with the inner wall of the tube 3, so that the swing arm shaft 8 is exactly coaxial with the inner wall of the titanium alloy tube 3 to be welded. At this time, the arc surface 32 of the arc-shaped protective cover 7 is closer to the inner wall of the titanium alloy tube 3 to be welded, so that the gap between the arc surface 32 of the arc-shaped protective cover 7 and the inner wall of the titanium alloy tube 3 to be welded is less than 2mm. In this state, inert gas is continuously injected into the inert gas protective chamber 31 through the flexible inert gas supply hose 4. The inert gas entering the inert gas protective chamber 31 can only leak through the narrow gap between the arc surface 32 and the inner wall of the titanium alloy tube 3 to be welded, so that the inert gas protective chamber 31 can maintain a relatively positive pressure state, thereby preventing external oxygen from flowing into the inert gas protective chamber 31, and thus maintaining a continuous inert gas environment in the inner area of ​​the weld seam 2 corresponding to the end of the welding torch 51.

[0049] Step 3: Based on the b setting, control the welding torch 51 to perform spray welding on the corresponding weld seam 2. At the same time, control the robotic arm 1 to slowly rotate the active welding robot 5 around the axis of the titanium alloy pipe 3 to be welded by a°, where a°≤5° and a is an integer divisible by 360. Thus, the welding torch 51 slowly welds a small section of the weld seam along the path of the corresponding weld seam 2 and then pauses.

[0050] During the process of the active welding robot 5 slowly rotating circumferentially around the axis of the titanium alloy tube 3 to be welded by a°, the permanent magnet unit 11 and the walking frame 12 follow the variable magnetic attraction electromagnet unit 16 of the active welding robot 5 to slowly rotate circumferentially around the axis of the titanium alloy tube 3 to be welded by a° under the attraction of the strong magnetic attraction force F2. At the same time, the two arc-shaped support plates 28 that are closely attached to the inner wall of the titanium alloy tube 3 to be welded remain in place, so that the arc-shaped protective cover 7 remains in place during this step, so that the swing arm 10 and the swing arm 9 change from being parallel to being at an angle of a° to each other, and the transverse return spring 23 adapts to elastic deformation and stores elastic potential energy.

[0051] During this step, the inner side of the welding torch 51 along the corresponding weld seam 2 is always within the coverage area of ​​the static inert gas protective chamber 31, thereby effectively preventing the inner side of the welding torch 51 along the corresponding weld seam 2 from being oxidized during this step.

[0052] Step four: While maintaining the B setting, wait for a period of time, more than 30 seconds, to allow the small section of weld that was welded in "Step three" to cool completely under the influence of inert gas.

[0053] Step 5: Control the variable magnetic attraction electromagnet unit 16 of the active welding robot 5 to enter position a. In position a, because the magnetic attraction force on the permanent magnet unit 11 is relatively smaller, the permanent magnet unit 11, under the strong pulling force of the four tension springs 25, is further away from the inner wall surface of the titanium alloy tube 3 to be welded compared to position b. This causes the two arc-shaped support plates 28 and the arc-shaped b-shaped protective cover 7 to be further away from the inner wall surface of the titanium alloy tube 3 to be welded, making the two arc-shaped support plates 28 and the arc-shaped b-shaped protective cover 7 further away from and separated from the inner wall surface of the titanium alloy tube 3 to be welded. In this state, the tension of the tension spring 25 alone resists the magnetic force F1 on the permanent magnet unit 11. It should be noted that the follow-up inert gas protection robot 6 of this scheme adopts a lightweight material design as a whole. The total weight G of the follow-up inert gas protection robot 6 is much smaller than the magnetic force F1 applied by the variable magnetic attraction electromagnet unit 16 to the permanent magnet unit 11. Specifically, at least 10×G<F1. Therefore, no matter what posture the follow-up inert gas protection robot 6 is in, in this device, the influence of gravity on the tension spring 25 and the return spring 23 is very small and can be ignored.

[0054] At this point, since the two arc-shaped support plates 28 have separated from the inner wall of the titanium alloy tube 3 to be welded, the b-swing arm 10 enters a free state. Under the restoring force of the transverse return spring 23, the b-swing arm 10 automatically resets, causing it to swing back to be parallel with the a-swing arm 9. The two arc-shaped support plates 28 and the arc-shaped b-protective cover 7 swing synchronously with the b-swing arm 10. Since there is a sufficient distance between the two arc-shaped support plates 28 and the arc-shaped b-protective cover 7 and the inner wall of the titanium alloy tube 3 to be welded, the two arc-shaped support plates 28 and the arc-shaped b-protective cover 7 will not interfere with the movement of the slight protrusions or other obstacles on the inner wall of the titanium alloy tube 3 to be welded during the synchronous swinging process with the b-swing arm 10.

[0055] At this point, the relative positional relationship between the active welding robot 5 and the follow-up inert gas shielded robot 6 is restored to the state at the end of "Step 1", thus completing a complete welding cycle.

[0056] Repeat steps 2 through 5 360 times to ensure that the entire weld seam 2 is completely welded while both the inside and outside are protected by inert gas.

[0057] The core technical effects of this patent:

[0058] 1. Dual-level dynamic adjustment of magnetic attraction force resolves the conflict between movement and sealing.

[0059] A-level (low magnetic force F1): The gap between the inner wall protective cover and the pipe wall is >5mm to avoid interference caused by uneven inner wall during movement; the four-way wheels contact the pipe wall only to ensure that the follow-up robot can freely follow the movement of the external active robot.

[0060] b gear (high magnetic force F2): Electromagnetic booster (F2≥2F1) permanent magnet unit 11 overcomes spring force, causing two arc support plates 28 to press tightly against the pipe wall with a pressure of ≥0.5MPa (support force ≥F2 / 2), making the arc support plates 28 closely fit the inner wall, forcing the swing arm shaft 8 to be coaxial with the pipe, physically forcing the swing arm shaft 8 to be aligned with the pipe axis, so that the gap between the protective cover arc surface 32 and the pipe wall is <2mm; forming a positive pressure airtight chamber, the inert gas flow controller dynamically adjusts the gas supply according to the gap, so that the b protective chamber 31 maintains a positive pressure of 15-30Pa (oxygen concentration <50ppm): inert gas only leaks from the micro-slit, effectively isolating oxygen and ensuring the gas environment of the welding area.

[0061] 2. Adaptive mechanical structure to improve stability.

[0062] Spring-guided system: The permanent magnet unit 11 is elastically connected to the frame via a tension spring 25 and a guide post 27. When the magnetic force increases, it automatically moves closer to the tube wall, and when the magnetic force decreases, it returns to its original position. The lateral return spring 23 drives the swing arm mechanism, which automatically returns to a parallel state when in position A.

[0063] 3. Step-by-step welding process to ensure gas protection throughout the process.

[0064] Welding stage (position b): The inner wall protective cover maintains a micro-gap of <2mm, forming a positive pressure airtight zone that covers the inside of the welding area; the robotic arm rotates only ≤5° each time to weld a small section, and the protective cover remains stationary to avoid movement that could damage the seal; Cooling and reset stage (position a): After welding, the weld is cooled for more than 30 seconds, and the gas continues to protect the weld; when switching to position a, the protective cover detaches from the pipe wall, and the spring reset mechanism keeps the swing arm parallel, allowing it to move to the next station without interference.

[0065] This patent innovatively solves the mutually exclusive requirements of movement freedom and static sealing in titanium alloy pipe welding through magnetic-mechanical dual-mode collaborative control. Its time-division multiplexing strategy (movement mode A / welding mode B) enables the equipment to achieve >99% oxidation-free welding zone in unseen pipelines, providing a reliable tool for high-requirement scenarios such as aerospace and nuclear power pipelines.

[0066] The above description 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 principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A magnetically attracted, synchronously walking, inert gas protected titanium alloy pipe welding robot, characterized in that: It includes a titanium alloy tube to be welded (3), an active welding robot (5), a follow-up inert gas protected robot (6), and a robotic arm (1); after the two titanium alloy tubes to be welded (3) are coaxially spliced, a ring of weld seam (2) is formed at the splice. The active welding robot (5) moves and attaches to the outer wall of the titanium alloy tube (3) under the connection of the robotic arm (1). The follow-up inert gas protection robot (6) moves and attaches to the inner wall of the titanium alloy tube (3). The follow-up inert gas protection robot (6) is magnetically attracted to the active welding robot (5) through a magnetic attraction device. The follow-up inert gas protection robot (6) follows the active welding robot (5) under the action of magnetic force. The active welding robot (5) includes a walking frame (15) and a welding machine (19); the walking frame (15) is fixed at the end of the robotic arm (1), and the four-way wheels (14) rotatably mounted around the walking frame (15) are tangentially rolled to the outer circumference of the titanium alloy pipe (3) to be welded; a welding machine base (17) is fixedly mounted on the back of the walking frame (15), and the welding machine (19) is fixedly mounted on the welding machine base (17) through a welding machine bracket (18); the end of the welding gun (51) of the welding machine (19) corresponds to the seam to be welded (2). A variable magnetic attraction electromagnet unit (16) is fixedly installed on the side of the walking frame (15) near the titanium alloy tube (3) to be welded. The magnetic field generated by the variable magnetic attraction electromagnet unit (16) passes through the wall of the titanium alloy tube (3) to be welded and generates magnetic attraction force on the follow-up inert gas protection robot (6). The follow-up inert gas protection robot (6) includes a walking frame (12), a permanent magnet unit (11), and an arc-shaped protective cover (7); the four-way wheels (13) mounted around the walking frame (12) are tangential to the inner wall of the titanium alloy tube (3) to be welded, and the permanent magnet unit (11) is located on the side of the walking frame (12) close to the wall of the titanium alloy tube (3); The back of the permanent magnet unit (11) is vertically fixed with guide posts (27) arranged in a rectangular array. The b-walking frame (12) is provided with ball guide sleeves (26) arranged in a rectangular array. Each guide post (27) guides and cooperates with each ball guide sleeve (26). The side of the b-walking frame (12) close to the permanent magnet unit (11) is connected to the back of the permanent magnet unit (11) by several tension springs (25). The variable magnetic attraction electromagnet unit (16) and the permanent magnet unit (11) are magnetically attracted to each other. Under the pull of several tension springs (25), the permanent magnet unit (11) always maintains a distance from the inner wall of the titanium alloy tube to be welded (3). The greater the magnetic attraction force applied by the variable magnetic attraction electromagnet unit (16), the closer the permanent magnet unit (11) will be to the inner wall of the titanium alloy tube to be welded (3), and the greater the stretching length of the tension springs (25).

2. The titanium alloy pipe welding robot with magnetic attraction synchronous walking and inert gas protection according to claim 1, characterized in that: Two a-arms (9) extending radially along the titanium alloy tube (3) to be welded are fixedly connected to the back sides of the permanent magnet unit (11). The ends of the two a-arms (9) are integrally connected to the bearing seats (60), and the arm shaft (8) is also included through the rotation of the bearing seats (60). Two circular arc support plates (28) are symmetrically arranged on both sides of the permanent magnet unit (11), and the outer arc radius of the circular arc support plate (28) is consistent with the inner wall radius of the titanium alloy tube (3) to be welded. Both of the concave sides of the two arc support plates (28) are integrally connected with a b swing arm (10) extending in the radial direction of the titanium alloy tube (3) to be welded. The ends of the two b swing arms (10) away from the arc support plates (28) are respectively fixedly connected to the two ends of the swing arm shaft (8). Each of the b swing arms (10) has a transverse return spring (23) symmetrically connected on both sides of the end near the arc support plate (28). The end of each transverse return spring (23) away from the b swing arm (10) is fixedly connected to the b traveling frame (12) through the return spring bracket (24). In the initial state, the b swing arm (10) is basically parallel to the a swing arm (9) under the pull and reset of several transverse return springs (23). The arc-shaped b protective cover (7) is fixedly connected to the b swing arm (10) via the connecting arm (41). Inside the arc-shaped b protective cover (7) is an arc-shaped b inert gas protection chamber (31) with the opening facing the inner wall of the titanium alloy tube to be welded (3). The end face of the arc-shaped b protective cover (7) near the inner wall of the titanium alloy tube to be welded (3) is an arc surface (32) that is consistent with the inner diameter of the inner wall of the titanium alloy tube to be welded (3). It also includes an inert gas flexible supply hose (4), and the inert gas outlet end of the inert gas flexible supply hose (4) is connected to the b inert gas protection chamber (31).

3. The titanium alloy pipe welding robot with magnetic attraction synchronous walking and inert gas protection according to claim 2, characterized in that: The variable magnetic attraction electromagnet unit (16) includes a position a and a position b. In position a, the variable magnetic attraction electromagnet unit (16) applies a magnetic force F1 to the permanent magnet unit (11). In position b, the variable magnetic attraction electromagnet unit (16) applies a magnetic force F2 to the permanent magnet unit (11). F1 < F2. In gear B, the permanent magnet unit (11) overcomes the tension of the tension spring (25) under the magnetic attraction of the variable magnetic attraction electromagnet unit (16), causing the permanent magnet unit (11) to move closer to the inner wall of the titanium alloy tube to be welded (3) until the convex arc surfaces of the two arc support plates (28) support and adhere to the inner wall of the titanium alloy tube to be welded (3) to form a balance. In this state, the tension of the tension spring (25) and the supporting force of the inner wall of the titanium alloy tube to be welded (3) on the two arc support plates (28) jointly resist the magnetic force F2 on the permanent magnet unit (11); in gear B, the two arc support plates (28) 8) The inner wall of the titanium alloy tube to be welded (3) is tightly fitted so that the swing arm shaft (8) is just coaxial with the titanium alloy tube to be welded (3). At this time, the arc surface (32) of the arc-shaped b protective cover (7) is fitted with the inner wall of the titanium alloy tube to be welded (3). In this state, if inert gas is continuously injected into the b inert gas protection chamber (31), the inert gas entering the b inert gas protection chamber (31) can only leak through the narrow gap between the arc surface (32) and the inner wall of the titanium alloy tube to be welded (3), so that the b inert gas protection chamber (31) can maintain a relatively positive pressure state. In position a, due to the relatively smaller magnetic attraction force on the permanent magnet unit (11), under the strong pulling force of the four tension springs (25), the permanent magnet unit (11) is further away from the inner wall of the titanium alloy tube to be welded (3) compared to position b. As a result, the two arc support plates (28) and the arc-shaped b protective cover (7) are further away from the inner wall of the titanium alloy tube to be welded (3), and the two arc support plates (28) and the arc-shaped b protective cover (7) are further away from and separated from the inner wall of the titanium alloy tube to be welded (3). In this state, the pulling force of the tension spring (25) alone resists the magnetic force F1 on the permanent magnet unit (11).

4. The titanium alloy pipe welding robot with magnetic attraction synchronous walking and inert gas protection according to claim 3, characterized in that: The total weight G of the follow-up inert gas protection robot (6) is 10×G<F1.

5. The working method of a magnetically attracted synchronous walking inert gas protected titanium alloy pipe welding robot according to claim 4, characterized in that: Step 1: The active welding robot (5) reaches the predetermined position on the outer wall of the titanium alloy pipe (3) to be welded, in gear a; Step 2: Enter gear b. In gear b, continuously inject inert gas into the inert gas protection chamber (31). Step 3: Based on the b gear, control the welding gun (51) to perform spray welding on the corresponding weld seam (2). At the same time, control the robotic arm (1) to slowly rotate the active welding robot (5) around the axis of the titanium alloy weld pipe (3) by a°. The welding gun (51) slowly welds a small section of the weld seam along the path of the corresponding weld seam (2) and then pauses. Step 4: While maintaining the B gear position, wait for a while; Step 5: Enter gear A. In gear A, the swing arm B (10) automatically resets under the restoring force of the transverse reset spring (23). Repeat steps two through five continuously to ensure that the entire weld seam is completely welded while both the inside and outside are protected by inert gas.

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