A friction stir welding method and a friction stir welding device

Abstract

The present application relates to a friction stir welding method and a friction stir welding device, wherein a workpiece to be welded is fixed to a welding table; a friction stir welding tool is close to a welding position of the workpiece to be welded; the friction stir welding device is started and the welding position is welded by the friction stir welding tool; a cold gas source supplies high-speed cooling gas to the rotating working friction stir welding tool; the cooling gas flows through the open gas inlet on the friction stir welding tool and the internal flow channel to take away the heat on the friction stir welding tool; the friction stir welding tool is rapidly cooled through the combination of forced convection and heat exchange; and the high-speed cooling gas flow enters the friction stir welding tool through the open gas inlet, which is different from the sealing rotary connection in the prior art, and there is no need to worry about the stability of the sealing rotary parts.

Description

Technical Field

[0001] This invention relates to the field of friction stir welding technology, and in particular to a friction stir welding method and a friction stir welding apparatus. Background Technology

[0002] Existing friction stir welding methods have the following drawbacks: First, surface cooling is used for the friction stir welding tools. Temperature control requires surface cooling of the welding needle at a distance from the tool, with heat conduction to the shoulder and welding needle position, rather than direct cooling of the center of the tool near the shoulder and welding needle, resulting in low cooling efficiency. Second, liquid cooling is prone to leakage after long-distance welding, affecting weld performance. Third, in friction stir welding, especially long-distance or thick-film welding, improper parameters leading to heat accumulation and excessively high welding temperatures can cause accelerated wear of the friction stir welding tools, shorten their lifespan, and reduce the mechanical properties of the weld. While reducing the rotation speed and increasing the welding speed can lower the tool temperature, this method is slow and it is difficult to directly adjust the welding parameters to optimal values. Therefore, there is an urgent need to develop a friction stir welding method to solve these problems. Summary of the Invention

[0003] This invention provides a friction stir welding method and a friction stir welding apparatus to solve the problems in the prior art.

[0004] The technical problem solved by this invention is achieved by the following technical solution:

[0005] In a first aspect, the present invention provides a friction stir welding method, the friction stir welding method comprising the following steps:

[0006] Secure the workpiece to be welded to the welding table;

[0007] Bring the friction stir welding tool close to the weld seam of the workpiece to be welded;

[0008] Start the friction stir welding device and weld the weld seam using the friction stir welding tool;

[0009] A cold air source supplies high-speed cooling gas to the rotating friction stir welding tool; the cooling gas carries away the heat from the friction stir welding tool after flowing through the open air inlet and internal flow channel on the tool.

[0010] In some embodiments, before moving the friction stir welding tool, a sleeve assembly is first fitted onto the outside of the friction stir welding tool;

[0011] The step of removing heat from the friction stir welding tool by passing the cooling gas through the open air inlet and the internal flow channel includes:

[0012] The cooling gas flows into the cavity between the sleeve assembly and the friction stir welding tool;

[0013] The first part of the cooling gas flows into the outside through the gap in the sleeve assembly, and the second part of the cooling gas enters the flow channel through the open air inlet; the amount of the first part of the cooling gas is less than the amount of the second part of the cooling gas.

[0014] The cooling gas in the flow channel carries away the heat from the friction stir welding tool and is discharged from the vent on the sleeve assembly.

[0015] In some embodiments, the cooling gas flows into the cavity between the sleeve assembly and the friction stir welding tool; a first portion of the cooling gas flows into the outside through a gap in the sleeve assembly; and a second portion of the cooling gas enters the flow channel through an open air inlet. The step of the cooling gas in the flow channel carrying away heat from the friction stir welding tool includes:

[0016] A cold air source supplies cooling gas into the first air passage within the sleeve assembly;

[0017] The cooling gas in the first air passage enters the open air inlet located in the cavity through the nozzle;

[0018] Cooling gas flows into the flow channel from the open air inlet.

[0019] In some embodiments, the cooling gas flows into the cavity between the sleeve assembly and the friction stir welding tool, a small portion of the cooling gas flows into the outside through a gap in the sleeve assembly, and a second portion of the cooling gas enters the flow channel through an open air inlet. The step of the cooling gas in the flow channel carrying away heat from the friction stir welding tool includes:

[0020] The cooling gas enters the cavity through a nozzle;

[0021] When the first part of the rotating flow channel aligns with the nozzle, the cooling gas enters from the first part of the flow channel and exits from the second part of the flow channel;

[0022] Alternatively, when the flow channel of the rotating second part aligns with the nozzle, the cooling gas enters from the flow channel of the second part and exits from the flow channel of the first part.

[0023] In some embodiments, the cooling gas enters the cavity through a nozzle; when a rotating first portion of the flow channel aligns with the nozzle, the cooling gas enters from the first portion of the flow channel and exits from the second portion of the flow channel; when a rotating second portion of the flow channel aligns with the nozzle, the cooling gas enters from the second portion of the flow channel and exits from the first portion of the flow channel, the step includes:

[0024] The cooling gas flows into a nozzle that is inclined toward the welding end of the friction stir welding tool;

[0025] It then enters the open air inlet that is adapted to the shape of the nozzle;

[0026] The cooling gas in the open air inlet continues to be delivered to the corresponding V-shaped flow channel.

[0027] In some embodiments, the step of removing heat from the friction stir welding tool by passing the cooling gas through the open air inlet and the internal flow channel includes:

[0028] The cooling gas enters the first flow channel from the open air inlet;

[0029] The cooling gas in the flow channel of the first part continues to be delivered to the cooling chamber inside the friction stir welding tool near the shoulder and / or welding needle for heat exchange;

[0030] The cooling gas in the cooling chamber continues to flow into the second flow channel and then out to remove the heat from the friction stir welding tool.

[0031] In some embodiments, the step of continuing to deliver cooling gas from the flow channel in the first part to the cooling chamber inside the friction stir welding tool near the shoulder and / or welding needle for heat exchange includes:

[0032] The cooling gas flows out through the flow channel after passing through the heat dissipation fins in the cooling chamber.

[0033] In some embodiments, the step of the cooling gas flowing out of the flow channel after passing through the heat dissipation fins in the cooling chamber includes:

[0034] The cooling gas enters the cooling chamber, then flows out through the flow channel after passing through multiple heat dissipation fins arranged around the inner wall of the cooling chamber.

[0035] In some embodiments, while a cold gas source supplies cooling gas to the rotating friction stir welding tool...

[0036] The protective gas source supplies protective gas to the second gas channel within the sleeve assembly, and the protective gas in the second gas channel continues to supply protective gas to the outside of the welding tip of the friction stir welding tool.

[0037] Secondly, the present invention provides a friction stir welding apparatus, wherein the friction stir welding apparatus is a friction stir welding apparatus for implementing the above-described method.

[0038] The beneficial effects of this invention are:

[0039] A cold air source delivers high-speed cooling gas to the rotating friction stir welding tool. The high-speed cooling gas flows through the open air inlet and internal channels of the friction stir welding tool, carrying away heat from the tool. This combination of forced convection and heat exchange rapidly dissipates heat from the tool, reducing wear and extending its service life. Furthermore, the open air inlet design allows high-speed cooling gas to enter the tool, unlike existing sealed rotating connections. This eliminates concerns about the stability of sealed rotating components. The open air inlet design also eliminates the need for sealed rotating components, resulting in a simpler and more compact overall structure. A simpler and more compact structure is more stable and less prone to requiring maintenance or replacement, which is particularly important for welding tools operating in high-temperature and high-speed environments. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the friction stir welding method in this invention;

[0042] Figure 2 This is a further schematic diagram of step S410 in the friction stir welding method of the present invention;

[0043] Figure 3 This is a first perspective view of the present invention;

[0044] Figure 4 This is a second perspective view of the present invention;

[0045] Figure 5 This is a front view structural diagram of the present invention;

[0046] Figure 6 for Figure 5 Sectional view along line AA;

[0047] Figure 7 forFigure 5 Sectional view along line BB;

[0048] Figure 8 for Figure 5 Sectional view along line LL;

[0049] Figure 9 This is a top view of the present invention;

[0050] Figure 10 for Figure 9 Sectional view along line FF;

[0051] Figure 11 for Figure 9 Cross-sectional view along line GG;

[0052] Figure 12 for Figure 9 A cross-sectional view along line HH.

[0053] Explanation of reference numerals in the attached figures:

[0054] 1. Friction stir welding tool; 2. Sleeve assembly; 3. Flow channel; 4. Connecting frame; 5. Air supply unit;

[0055] 11. Stirring head; 12. Shaft shoulder; 13. Welding pin; 111. Cooling chamber; 112. Heat dissipation fins;

[0056] 113. First shaft segment; 114. Second shaft segment; 115. Annular groove;

[0057] 21. Main sleeve; 22. Connecting sleeve; 23. Protective gas sleeve; 24. Exhaust port;

[0058] 211. First airway; 212. Second airway; 221. Bearing assembly; 231. Cavity;

[0059] 31. Open air intake; 51. Nozzle. Detailed Implementation

[0060] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific illustrations.

[0061] To solve the above technical problems, please refer to Figures 1 to 9 As shown, the first aspect of this application proposes a friction stir welding method that can cool the friction stir welding tool 1 in real time by using an open-type high-speed cooling gas intake. This method can achieve rapid and effective cooling of the friction stir welding tool 1 and ensure that the overall structure of this application is compact and not easily damaged.

[0062] Reference Figure 1In some embodiments of this application, the friction stir welding method includes the following steps:

[0063] Step S100: Fix the workpiece to be welded to the welding table; the above steps can fix the workpiece to be welded to facilitate its stability during the welding process.

[0064] Step S200: Bring the friction stir welding tool 1 close to the weld seam of the workpiece to be welded; the above steps can move the friction stir welding tool 1 to the corresponding welding position, prepare for the subsequent welding work, and improve welding efficiency.

[0065] Step S300: Start the friction stir welding device and weld the weld seam using the friction stir welding tool 1; the above steps can be performed by welding the weld seam using the friction stir welding tool 1 to achieve welding of the workpiece to be welded.

[0066] Step S400: A cold air source supplies high-speed cooling gas to the rotating friction stir welding tool 1; the cooling gas flows through the open air inlet 31 and the internal flow channel 3 on the friction stir welding tool 1, carrying away the heat from the friction stir welding tool 1. The above step allows the high-speed cooling gas to flow through the open air inlet 31 and the internal flow channel 3 on the friction stir welding tool 1, carrying away the heat from the tool; by combining forced convection and heat exchange, the friction stir welding tool 1 is rapidly cooled down in real time, reducing wear and tear and extending its service life; simultaneously, the open air inlet allows high-speed cooling airflow into the friction stir welding tool, unlike the sealed rotating connection method used in the prior art, eliminating concerns about the stability of sealed rotating parts. Furthermore, since the open air inlet method does not require sealed rotating components, the overall structure of this application is simpler and more compact. A simpler and more compact structure is more stable and less prone to requiring maintenance or replacement, which is particularly important for welding tools that need to operate in high-temperature and high-speed environments.

[0067] It should be noted that the welding table mentioned above is the welding table of the friction stir welding device. The welding table can be used to place the workpiece to be welded, and if necessary, it can be clamped and fixed by a special fixture. Of course, when the workpiece to be welded is heavy and the welding precision requirement is low, the weight of the workpiece itself can be used to maintain stability during the welding process, without the need for auxiliary fixation by a fixture.

[0068] It should be noted that the workpiece to be welded can be a single workpiece with a weld, or at least two workpieces that need to be welded and can be combined to form a weld.

[0069] Referring to the accompanying drawings, in some embodiments of this application, before moving the friction stir welding tool 1,

[0070] Step S350: First, a sleeve assembly 2 is fitted onto the outside of the friction stir welding tool 1; the sleeve assembly 2 in the above step is used to form a cavity that is partially connected to the outside world between itself and the friction stir welding tool 1, and is also used to provide a transfer carrier for cooling the rotating friction stir welding tool 1; it can also be used to provide good rotational support for the friction stir welding tool 1.

[0071] The step of removing heat from the friction stir welding tool 1 by the cooling gas flowing through the open air inlet 31 and the internal flow channel 3 includes:

[0072] Step S410: The cooling gas flows into the cavity between the sleeve assembly 2 and the friction stir welding tool 1; a first part of the cooling gas flows into the outside through the gap on the sleeve assembly 2, and a second part of the cooling gas enters the flow channel 3 through the open air inlet 31; the cooling gas in the flow channel 3 carries away the heat from the friction stir welding tool 1 and is discharged from the exhaust hole 24 on the sleeve assembly 2. The amount of the first part of the cooling gas is less than the amount of the second part of the cooling gas. The above steps ensure that the cooling gas does not directly flow into the air in large quantities, but accumulates in the cavity first, and then enters the friction stir welding tool 1, preventing a large amount from dissipating and effectively ensuring sufficient cooling gas to dissipate heat from the friction stir welding tool. This invention ensures that the cooling gas inlet and the friction stir welding tool 1 do not need to be connected by a rotary sealing assembly, but can adopt an open inlet method. The cavity design prevents the cooling gas from escaping rapidly, and the second part of the high-speed cooling airflow will quickly rush into the flow channel 3 to cool the friction stir welding tool 1. Only the first part will escape from the cavity to the outside, ensuring good heat dissipation performance of the friction stir welding tool 1. At the same time, the open inlet design makes the structure of this application simpler and more compact, and less prone to problems. In addition, the cooling gas can fully remove the heat inside the friction stir welding tool 1 and discharge it into the external environment, thereby achieving a good heat dissipation effect for the friction stir welding tool.

[0073] In some embodiments of this application, cooling gas flows into the cavity between the sleeve assembly 2 and the friction stir welding tool 1. A first portion of the cooling gas flows into the outside through a gap in the sleeve assembly 2, and a second portion of the cooling gas enters the flow channel 3 through an open air inlet 31. The step of the cooling gas in the flow channel 3 carrying away the heat from the friction stir welding tool 1 includes:

[0074] Step S411: The cold air source delivers cooling gas to the first air passage 211 inside the sleeve assembly 2; the cooling gas in the first air passage 211 enters the open air inlet 31 located in the cavity through the nozzle 51; the cooling gas in the open air inlet 31 flows into the flow channel 3; the above steps ensure that the cold air source first passes through the first air passage 211 inside the sleeve assembly 2 and then sprays out from the nozzle 51 into the flow channel 3, which plays a good guiding and transmission role for the cold air source. At the same time, through the cooperation of the nozzle 51 and the open air inlet 31, the high-speed cooling airflow can quickly enter the interior of the friction stir welding tool 1 to carry away the heat.

[0075] In some embodiments of this application, the step of the cooling gas in the first air passage 211 entering the open air inlet 31 located in the cavity through the nozzle 51 includes:

[0076] Step S4111: The cooling gas enters the cavity through the nozzle 51; when the rotating first part of the flow channel 3 aligns with the nozzle 51, the cooling gas enters from the first part of the flow channel 3 and flows out from the second part of the flow channel 3; or when the rotating second part of the flow channel 3 aligns with the nozzle 51, the cooling gas enters from the second part of the flow channel 3 and flows out from the first part of the flow channel 3; the above steps, by intermittently aligning the nozzle 51 with the flow channel 3, enable the high-speed cooling airflow to continuously enter the flow channel 3 inside the friction stir welding tool 1 for heat exchange and rapid heat discharge, thereby reducing the wear of the friction stir welding tool 1.

[0077] In some embodiments of this application, the cooling gas enters the cavity through nozzle 51. When the rotating first part of the flow channel 3 aligns with the nozzle 51, the cooling gas enters from the first part of the flow channel 3 and exits from the second part of the flow channel 3; when the rotating second part of the flow channel 3 aligns with the nozzle 51, the cooling gas enters from the second part of the flow channel 3 and exits from the first part of the flow channel 3, the steps include:

[0078] Step S41111: Cooling gas flows into the nozzle 51, which is inclined toward the welding end of the friction stir welding tool 1; then it enters the open air inlet 31, which is adapted to the shape of the nozzle 51; the cooling gas in the open air inlet 31 continues to be delivered to the corresponding V-shaped flow channel 3; the above steps allow the high-speed cooling airflow in the nozzle 51 to enter the V-shaped flow channel with the same inclination angle as the nozzle 51, so as not to block the high-speed cooling airflow, thus ensuring the forced convection capability of the high-speed cooling airflow and facilitating the rapid dissipation of heat.

[0079] In some embodiments of this application, cooling gas flows into a nozzle 51 that is inclined toward the welding end of the friction stir welding tool 1; then enters an open air inlet 31 adapted to the shape of the nozzle 51; the cooling gas in the open air inlet 31 continues to be delivered to a corresponding V-shaped flow channel 3, including:

[0080] Step S412: Cooling gas enters the first flow channel 3 from the open air inlet 31; the cooling gas in the first flow channel 3 continues to be transported to the cooling chamber 111 inside the friction stir welding tool 1 near the shoulder 12 and / or welding needle 13 for heat exchange; the cooling gas in the cooling chamber 111 continues to flow into the second flow channel 3 and is discharged to remove the heat from the friction stir welding tool 1; the above steps enable the high-speed cooling gas to undergo heat exchange in the cooling chamber 111 near the shoulder 12 and / or welding needle 13 after entering the friction stir welding tool 1, which can improve the heat dissipation rate inside the friction stir welding tool 1. At the same time, the heat at the welding position with the highest temperature can be quickly and effectively conducted and discharged at the location of the cooling chamber 111 near the shoulder 12 and / or welding needle 13, thereby minimizing the temperature loss of the friction stir welding tool 1.

[0081] In some embodiments of this application, the cooling gas enters the first flow channel 3 from the open inlet 31; the cooling gas in the first flow channel 3 continues to be delivered to the cooling chamber 111 inside the friction stir welding tool 1 near the shoulder 12 and / or the welding needle 13 for heat exchange, including:

[0082] Step S4121: The cooling gas flows out of the flow channel 3 after passing through the heat dissipation fins 112 in the cooling chamber 111; the above steps enable the cooling gas to have a larger heat exchange area in the cooling chamber 111, and facilitate the rapid conduction of heat from the friction stir welding tool 1, effectively improving heat dissipation.

[0083] In some embodiments of this application, the step of cooling gas flowing out of the flow channel 3 after passing through the heat dissipation fins 112 in the cooling chamber 111 includes:

[0084] Step S41211: Cooling gas enters the cooling chamber 111, and then flows out from the flow channel 3 through multiple heat dissipation fins 112 arranged around the inner wall of the cooling chamber 111. The above steps of this application are arranged with several heat dissipation fins 112 around the cooling chamber 111 to obtain the maximum heat dissipation area in a limited space, which is conducive to the full heat exchange and further reduces the wear of the friction stir welding tool 1.

[0085] In some embodiments of this application, the following is performed simultaneously: The cooling gas is supplied by a cold gas source to the rotating friction stir welding tool 1.

[0086] Step S405: The protective gas source supplies protective gas to the second gas channel 212 in the sleeve assembly 2. The protective gas in the second gas channel 212 continues to supply protective gas to contact the outside of the welding tip of the friction stir welding tool 1. The above steps input protective gas to the processing area of ​​the welding tool and the workpiece while the friction stir welding tool 1 is performing welding work, so as to prevent the plastic deformation of the welded workpiece from oxidizing.

[0087] Secondly, this application proposes a friction stir welding apparatus, which is a friction stir welding apparatus for implementing the above-described method.

[0088] Friction stir welding apparatus includes a friction stir welding tool 1 and a sleeve assembly 2 fitted around the outside of the friction stir welding tool 1. The sleeve assembly 2 is fixedly connected to a connecting frame 4. The friction stir welding tool 1 can rotate to complete the welding work. At least one flow channel 3 is provided inside the friction stir welding tool 1. The first end of the flow channel 3 is an open air inlet 31, and the second end of the flow channel 3 is an exhaust port. Cooling gas enters from the open air inlet 31 and exits from the exhaust port to remove the heat inside the friction stir welding tool 1. The sleeve assembly 2 is provided with an air supply part 5, which provides cooling gas to the open air inlet 31 so that it enters the flow channel 3. Cooling friction stir welding tool 1; In this invention, by setting a flow channel 3 inside the friction stir welding tool 1, the cooling gas can directly reach the part inside the friction stir welding tool 1 that needs to be cooled to remove heat, thereby achieving a better cooling effect; At the same time, the air supply method of the air supply unit 5 can be: when the friction stir welding tool 1 drives the open air inlet 31 to rotate, when the open air inlet 31 rotates to be aligned or approximately aligned with the air supply port of the air supply unit 5, the cooling gas can enter the flow channel 3 to cool the friction stir welding tool 1. Unlike the general air intake method, no special sealing design is required, and the overall structure is more stable and reliable.

[0089] The open air inlet 31 can be understood as not requiring a strictly sealed environment for its air intake method; it can also be understood as having a gap between the open air inlet 31 and the air supply port of the air supply unit 5, and not being directly connected; it can also be understood as not being in a sealed environment when the open air inlet 31 is connected to the air supply port of the air supply unit 5. The above description does not limit the open air inlet 31, but is only an explanation for ease of understanding.

[0090] Specifically, referring to the attached drawings, a cavity is formed between the sleeve assembly 2 and the friction stir welding tool 1. The cavity is connected to the outside to discharge gas. The air supply port of the air supply section 5, the open air inlet 31 of the flow channel 3, and the exhaust port are all located inside the cavity. The air supply port of the air supply section 5 and the open air inlet 31 are not in contact, but they can allow open air intake of the flow channel 3, avoiding a strict sealing design and making the structure simpler and more reliable.

[0091] Optionally, there can be two, three, four or five flow channels 3, and the specific number can be set according to the actual situation, without any limitation. Preferably, multiple flow channels 3 have a common intersection point, which facilitates the rapid flow of gas entering the flow channel 3.

[0092] In one optional embodiment, the friction stir welding tool 1 includes a stirring head 11, a shoulder 12, and a welding needle 13 connected in sequence. Optionally, the friction stir welding tool 1 can be manufactured using additive manufacturing. Optionally, the first end of the stirring head 11 (in actual operation, the first end can be understood as the upper end) is connected to a drive spindle, which drives the friction stir welding tool 1 to rotate. The welding needle 13 and the shoulder 12 (in actual operation, the shoulder 12 and the welding needle 13 can be considered to be located on the lower side of the stirring head) are used to contact and cooperate with the workpiece to be welded (refer to the accompanying drawings for understanding). Preferably, a cooling cavity 111 is provided inside the stirring head 11 near the shoulder 12 and / or the welding needle 13, and the cooling cavity 111 is connected to the flow channel 3, thereby... This allows the cooling gas to directly reach the shoulder 12 and / or welding pin 13, where the heat is highest, for rapid cooling. Simultaneously, the cooling chamber 111 can be used to accelerate the cooling efficiency of the friction stir welding tool 1. Preferably, the flow channel 3 can be V-shaped, with the intersection of the V-shaped flow channels being the location of the cooling chamber 111, allowing the cooling gas to get closer to the heat source and carry away heat. Preferably, the nozzle 51 is inclined and positioned in the extension direction of the V-shaped flow channel, allowing the airflow to enter quickly. Preferably, the sidewall of the second shaft section 114 has an annular groove to accommodate the inclined nozzle 51, preventing interference with the nozzle 51 when the second shaft section 114 rotates. Preferably, the annular groove communicates with the annular groove, facilitating rapid entry of airflow from the nozzle into the flow channel.

[0093] Preferably, the cooling cavity 111 is provided with heat sinks to further improve the heat dissipation effect of the cooling cavity 111; preferably, the heat sinks include multiple heat sink fins 112, which increase the heat dissipation area; and the multiple heat sink fins 112 are arranged longitudinally around the inner wall of the cooling cavity, and there are gaps between the heat sink fins to facilitate airflow.

[0094] In an optional embodiment, the sleeve assembly 2 further includes a connecting sleeve 22 fixedly connected to the connecting frame 4. The connecting sleeve 22 is rotatably connected to the friction stir welding tool 1, allowing the friction stir welding tool 1 to rotate inside the sleeve assembly 2. Preferably, the connecting sleeve 22 and the friction stir welding tool 1 are connected via a bearing assembly 221. Preferably, the bearing assembly 221 includes a bearing sleeve and a bearing, and the connecting sleeve 22 and the bearing sleeve are detachably connected. Optionally, the connecting sleeve 22 and the bearing sleeve are connected by screws for easy disassembly and assembly. One or more bearings can be installed inside the bearing sleeve. The outer ring of the bearing is connected to the inner wall of the bearing sleeve, and the inner ring of the bearing is connected to the friction stir welding tool 1 and fixed by a platform and a locking buckle. Preferably, the bearing sleeve has several through holes to reduce weight while increasing rigidity.

[0095] In an optional embodiment, the sleeve assembly 2 further includes a main sleeve 21, which is sleeved on the outside of the friction stir welding tool 1 and connected to the side of the connecting sleeve 22 facing the welding needle 13. The side wall of the main sleeve 21 has at least one first air passage 211. The air supply unit 5 includes a nozzle 51, the first end of the first air passage 211 is connected to the corresponding nozzle 51, the second end of the first air passage 211 is externally connected to a cold air source, and the nozzle 51's air outlet faces the open air inlet 31 for supplying air to it. A high-speed airflow is supplied to the first air passage 211 through the cold air source. Airflow enters along the first air passage 211 and exits from the nozzle 51. When the friction stir welding tool 1 rotates the open air inlet 31 to align with or approximately align with the jet nozzle 51, the high-speed airflow enters the flow passage 3 and then carries away the heat in the stirring head 11. Preferably, the first air passage 211 is connected to the cold air source through a hose. Further, the hose can be a PU tube. Preferably, the cold air source is an air compressor. Preferably, the main sleeve 21 is manufactured using an additive manufacturing method. Preferably, the main sleeve 21 and the connecting sleeve 22 are designed as separate parts for easy installation and disassembly.

[0096] In one alternative implementation, nozzles 51 may be configured as two, three, or four as needed, with no limitation on the specific number.

[0097] In one optional embodiment, a cavity is formed between the main sleeve 21 and the stirring head 11. The nozzle 51 and the open air inlet 31 are both located inside the cavity, and the cavity is connected to the outside through some gaps. The nozzle 51 continuously injects air into the cavity. When the nozzle 51 and the open air inlet 31 are misaligned, a small portion of the gas is discharged into the outside through the gap between the main sleeve 21 and the connecting sleeve 22. Part of the gas enters the flow channel for cooling, and the other part of the gas remains in the cavity, causing the air pressure in the cavity to continuously increase. When the nozzle 51 and the open air inlet 31 are aligned or approximately aligned, the high-pressure airflow in the cavity enters the flow channel 3 more quickly, thereby producing a better heat removal effect.

[0098] In one optional embodiment, the stirring head 11 includes a first shaft segment 113 and a second shaft segment 114 near the shoulder 12. The first shaft segment 113 is rotatably connected to the sleeve assembly 2. Preferably, the first shaft segment 113 is connected to the connecting sleeve 22 by a bearing, which makes the rotation of the friction stir welding tool 1 smoother. The second shaft segment 114 has an annular groove 115 corresponding to the nozzle 51, and the nozzle 51 can be located in the annular groove 115, so that the airflow ejected from the nozzle 51 can more easily enter the flow channel 3 through the annular groove 115, thereby achieving a better cooling effect on the stirring head 11. Optionally, the gap between the nozzle 51 and the annular groove 115 is small to avoid wasting airflow.

[0099] In one optional embodiment, at least one second air passage 212 is formed on the side wall of the main sleeve 21. The inlet end of the second air passage 212 is connected to a protective gas source, and the protective gas can be argon, helium, etc. The outlet end of the second air passage 212 faces the position of the shoulder 12 and / or the welding pin 13. The protective gas is supplied to the second air passage 212 through the protective gas source, and then the protective gas is input to the processing area of ​​the welding tool and the workpiece to be welded to prevent oxidation of the workpiece under plastic deformation. Preferably, the second air passage 212 and the protective gas source are connected by a hose. Preferably, the hose is selected as a PU tube.

[0100] Furthermore, the sleeve accessory also includes a protective gas sleeve 23, which is connected to the side of the main sleeve 21 facing the welding needle 13. The protective gas sleeve 23 has a cavity 231 inside, the inlet end of which is connected to the outlet end of the second gas channel 212. The outlet end of the cavity 231 extends to the shoulder 12 and / or the welding needle 13 to shorten the distance between the outlet end of the cavity 231 and the friction stir welding tool 1, ensuring minimal gas loss during the protective gas ejection to the shoulder 12 and / or the welding needle 13. Preferably, the outlet end of the cavity 231 is an annular outlet, facilitating the uniform spraying of protective gas onto the outside of the shoulder 12 and / or the welding needle 13 for protection. Preferably, the protective gas sleeve 23 has an inverted conical structure to prevent interference with the workpiece or other components during welding.

[0101] In one alternative embodiment, the connecting sleeve 22, the main body sleeve 21, and the protective gas sleeve 23 are designed as separate units, which facilitates the assembly and disassembly of the device.

[0102] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this application, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0103] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A friction stir welding method, characterized in that, The friction stir welding method includes the following steps: Secure the workpiece to be welded to the welding table; Bring the friction stir welding tool (1) close to the weld seam of the workpiece to be welded; Start the friction stir welding device and weld the weld seam using the friction stir welding tool (1); A cold air source supplies high-speed cooling gas to the rotating friction stir welding tool (1); The cooling gas carries away the heat from the friction stir welding tool (1) after flowing through the open air inlet (31) and the internal flow channel (3) on the tool (1). Before moving the friction stir welding tool (1), first install the sleeve assembly (2) on the outside of the friction stir welding tool (1); The step of the cooling gas carrying away the heat from the friction stir welding tool (1) after flowing through the open air inlet (31) and the internal flow channel (3) includes: The cooling gas flows into the cavity between the sleeve assembly (2) and the friction stir welding tool (1); The first part of the cooling gas flows into the outside through the gap on the sleeve assembly (2), and the second part of the cooling gas enters the flow channel (3) through the open air inlet (31). The amount of the first part of the cooling gas is less than the amount of the second part of the cooling gas. The cooling gas in the flow channel (3) carries away the heat from the friction stir welding tool (1) and is discharged from the exhaust port (24) on the sleeve assembly (2).

2. The friction stir welding method as described in claim 1, characterized in that, The cooling gas flows into the cavity between the sleeve assembly (2) and the friction stir welding tool (1). A first portion of the cooling gas flows into the outside through a gap in the sleeve assembly (2), and a second portion of the cooling gas enters the flow channel (3) through an open air inlet (31). The step of the cooling gas in the flow channel (3) carrying away the heat from the friction stir welding tool (1) includes: A cold air source supplies cooling gas to the first air passage (211) inside the sleeve assembly (2); The cooling gas in the first air passage (211) enters the open air inlet (31) located in the cavity through the nozzle (51); Cooling gas flows into the flow channel (3) from the open air inlet (31).

3. The friction stir welding method as described in claim 2, characterized in that, The step of the cooling gas in the first air passage (211) entering the open air inlet (31) located in the cavity through the nozzle (51) includes: The cooling gas enters the cavity through a nozzle (51); When the first part of the flow channel (3) is aligned with the nozzle (51) during rotation, the cooling gas enters from the first part of the flow channel (3) and exits from the second part of the flow channel (3); Or when the flow channel (3) of the rotating second part is aligned with the nozzle (51), the cooling gas enters from the flow channel (3) of the second part and flows out from the flow channel (3) of the first part.

4. The friction stir welding method as described in claim 3, characterized in that, The cooling gas enters the cavity through the nozzle (51). When the rotating first part of the flow channel (3) aligns with the nozzle (51), the cooling gas enters from the first part of the flow channel (3) and flows out from the second part of the flow channel (3). The steps of the rotating second part of the flow channel (3) aligning with the nozzle (51) and the cooling gas entering from the second part of the flow channel (3) and flowing out from the first part of the flow channel (3) include: The cooling gas flows into a nozzle (51) that is inclined toward the welding end of the friction stir welding tool (1); It then enters the open air inlet (31) that is adapted to the shape of the nozzle (51); The cooling gas in the open air inlet (31) continues to be delivered to the corresponding V-shaped flow channel (3).

5. The friction stir welding method according to any one of claims 1-4, characterized in that, The step of the cooling gas carrying away the heat from the friction stir welding tool (1) after flowing through the open air inlet (31) and the internal flow channel (3) includes: The cooling gas enters the first flow channel (3) from the open air inlet (31); The cooling gas in the flow channel (3) of the first part continues to be delivered to the cooling chamber (111) of the friction stir welding tool (1) near the shoulder (12) and / or the welding needle (13) for heat exchange; The cooling gas in the cooling chamber (111) continues to flow into the second flow channel (3) and is discharged to carry away the heat from the friction stir welding tool (1).

6. The friction stir welding method as described in claim 5, characterized in that, The step of continuing to deliver the cooling gas in the flow channel (3) of the first part to the cooling chamber (111) inside the friction stir welding tool (1) near the shoulder (12) and / or the welding needle (13) for heat exchange includes: The cooling gas flows out from the flow channel (3) after passing through the heat dissipation fins (112) in the cooling chamber (111).

7. The friction stir welding method as described in claim 6, characterized in that, The step of the cooling gas flowing out of the flow channel (3) after passing through the heat dissipation fins (112) in the cooling chamber (111) includes: The cooling gas enters the cooling chamber (111), and then flows out through the flow channel (3) after passing through multiple heat dissipation fins (112) arranged around the inner wall of the cooling chamber (111).

8. The friction stir welding method according to any one of claims 1-4, characterized in that, While the cold gas source supplies cooling gas to the rotating friction stir welding tool (1), The protective gas source supplies protective gas to the second gas passage (212) in the sleeve assembly (2), and the protective gas in the second gas passage (212) continues to supply protective gas to contact the outside of the welding tip of the friction stir welding tool (1).

9. A friction stir welding apparatus, characterized in that, The friction stir welding apparatus is a friction stir welding apparatus for implementing the method of any one of claims 1-8.

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