Heavy load friction stir welding retractable stir head

Abstract

The application relates to a heavy-load friction stir welding retractable stir head which is installed at the front end of a heavy-load friction stir welding spindle with a stir pin retracting function, and comprises a stir pin and a shaft shoulder in a split structure, wherein the stir pin head is a spherical section with a taper thread; the heavy-load friction stir welding spindle with the stir pin retracting function controls the linear retracting movement of the stir pin into the shaft shoulder under the synchronous rotating state of the shaft shoulder. The heavy-load friction stir welding retractable stir head realizes the design of a large-torque transmission structure of the friction stir welding, is installed and matched with the heavy-load friction stir welding spindle with the stir pin retracting function, realizes the elimination of a welding ring gap keyhole through continuous and stable retracting during the welding process, and realizes the high-quality, efficient and reliable automatic welding forming of a new generation manned launch vehicle fuel storage tank box body and other large-thickness high-strength aluminum alloy box bodies.

Description

Technical Field

[0001] This invention relates to the field of automated equipment technology for circumferential seam assembly and welding of thick, high-strength aluminum alloy tanks such as fuel tank bodies for manned launch vehicles, and in particular to a heavy-duty friction stir welding retractable stirring head suitable for the closed circumferential seam assembly and welding of thick, high-strength aluminum alloy tank bodies such as fuel tank bodies for manned launch vehicles. Background Technology

[0002] The welded area of ​​the fuel tank for my country's new-generation manned launch vehicle is over 22mm thick, with a total length of 40m. Using traditional fusion welding processes poses significant development risks. Currently, welding is one of the key technologies in rocket structure manufacturing within the aerospace industry. The application of welding processes and structures using thick, high-strength aluminum alloys such as 2219 aluminum alloy and 2195 aluminum-lithium alloy not only effectively improves the efficiency and reliability of launch vehicles but also greatly promotes the overall development of aerospace technology and enhances humanity's ability to explore outer space. To effectively utilize outer space resources, the development of various large launch vehicles has become a crucial foundation for the aerospace industry. Replacing the energy-intensive and polluting traditional fusion welding technology with advanced, efficient, and energy-saving friction stir welding green manufacturing technology to achieve efficient and lightweight manufacturing of aerospace structures has become a major trend in the development of large launch vehicles.

[0003] Friction stir welding (FSW) is a novel metal welding process that utilizes the high temperatures generated by the rotation and extrusion of a stirring head to induce plastic flow in the metal material near the stirring head, forming a dense microstructure at the joint of two workpieces, thus achieving the welding of metal parts. Compared to traditional welding processes, FSW offers advantages such as high joint quality, fewer defects, less deformation, reduced labor intensity for workers, and a green and pollution-free welding process. Since rocket fuel tanks are special pressure vessels that require a stable and continuous supply of fuel and oxidizer to the engine during rocket flight, the weld seams must maintain strict airtightness. Conventional FSW welding, due to the integrated needle and shoulder features of the stirring head, results in a circumferential keyhole at the weld end. Therefore, conventional FSW welding is often used for longitudinal welds, and the keyhole area is removed as a allowance after welding.

[0004] The friction stir welding of the circumferential seam of the rocket fuel tank requires a retractable friction stir welding process capable of removing keyholes in the weld. This involves a separate structure for the stirring pin and the shoulder. After the main shaft completes a full circumference weld, the stirring pin can be uniformly retracted along a certain length of the weld towards the shoulder to eliminate the keyhole. This retractable friction stir welding process places higher demands on the stirring head. Firstly, the stirring head needs to withstand significant upsetting and forward resistance loads, while the shoulder and stirring pin must rotate synchronously to output high torque to meet the requirements of the friction stir welding process. Secondly, the stirring pin must be able to retract under heavy-load conditions by coaxial linear relative motion with the shoulder under the servo drive of the retraction device. Summary of the Invention

[0005] The purpose of this invention is to provide a heavy-duty friction stir welding head with a retractable stirring head, which realizes a high-torque transmission structure design for friction stir welding. It is installed and matched with a heavy-duty friction stir welding spindle with a stirring pin retraction function. Through continuous and stable retraction during the welding process, the keyhole of the weld circumferential seam is eliminated, enabling high-quality, efficient and reliable automated welding of thick, high-strength aluminum alloy tanks such as the fuel tank body of the new generation of manned launch vehicles.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A heavy-duty friction stir welding retractable stirring head is installed at the front end of a heavy-duty friction stir welding spindle with stirring pin retraction function. It includes a stirring pin and a shoulder with a split structure. The head of the stirring pin is a spherical cross-section with a tapered thread. The heavy-duty friction stir welding spindle with stirring pin retraction function controls the stirring pin to make a linear retraction motion inward of the shoulder while rotating synchronously with the shoulder.

[0008] In one embodiment, three tapered threads are evenly distributed on the spherical cross-section of the stirring needle head, and the three tapered threads have the same depth.

[0009] Furthermore, the heavy-duty friction stir welding spindle with stirring pin retraction function includes a heavy-duty friction stir welding spindle and a heavy-duty friction stir welding stirring pin retraction device installed at the rear end of the heavy-duty friction stir welding spindle. The heavy-duty friction stir welding retractionable stirring head is installed at the front end of the heavy-duty friction stir welding spindle. The stirring pin is controlled to rotate synchronously with the shaft shoulder by the heavy-duty friction stir welding spindle, and the stirring pin is controlled to perform a linear retraction motion inward of the shaft shoulder while rotating synchronously with the shaft shoulder by the heavy-duty friction stir welding stirring pin retraction device.

[0010] Furthermore, the heavy-duty friction stir welding spindle includes a hollow motor, which comprises a hollow motor rotor and a hollow motor rotor shaft. The hollow motor rotor is axially fixedly connected to the hollow motor rotor shaft, and the rotational torque output by the hollow motor rotor to the hollow motor rotor shaft is synchronously transmitted to the shaft shoulder and the stirring needle, causing the shaft shoulder and the stirring needle to rotate synchronously. The heavy-duty friction stir welding stirring needle retraction device includes a rotary separation mechanism and a planetary screw servo drive mechanism, as well as a stirring needle retraction shaft. The stirring needle retraction shaft is coaxially installed inside the hollow motor rotor shaft, with its front end extending out of the hollow motor rotor shaft and inserted into the shaft shoulder from the rear end, and its rear end extending out of the hollow motor rotor shaft and sequentially connected to the rotary separation mechanism and the planetary screw servo drive mechanism. The mechanism is connected as follows: the stirring needle is coaxially mounted inside the shoulder, with its front end extending out of the shoulder and its rear end inserted into the stirring needle retraction shaft. The stirring needle has a degree of freedom to move along the axial centerline of the hollow motor rotor shaft within the shoulder, referred to as the first degree of freedom. The stirring needle retraction shaft has a degree of freedom to move along the axial centerline of the hollow motor rotor shaft within the hollow motor rotor shaft, referred to as the second degree of freedom. The first and second degrees of freedom are consistent. The planetary screw servo drive mechanism, in cooperation with the rotation separation mechanism, drives the stirring needle retraction shaft to move along the axial centerline of the hollow motor rotor shaft within the hollow motor rotor shaft, thereby causing the stirring needle to retract into the shoulder along the axial centerline of the hollow motor rotor shaft.

[0011] Furthermore, the heavy-duty friction stir welding retractable stirring head also includes a stirring head clamping handle, the rear end of which is inserted into the hollow motor rotor shaft from the front end of the hollow motor rotor shaft; the rear end of which is inserted into the stirring head clamping handle from the front end of the stirring head clamping handle; and the front end of the stirring needle retraction shaft is inserted into the shoulder from the rear end of the stirring head clamping handle and the rear end of the shoulder in sequence.

[0012] Furthermore, the hollow motor rotor shaft has a through-hole inside, including a first shaft hole at the front of the hollow motor rotor shaft and a second shaft hole at the rear of the hollow motor rotor shaft. The first shaft hole and the second shaft hole communicate to form a through-hole, and the first shaft hole, the second shaft hole, and the hollow motor rotor shaft are coaxially aligned. The rear part of the stirring pin retraction shaft matches the second shaft hole, ensuring that the rear part of the stirring pin retraction shaft is inside the second shaft hole and coaxially aligned with the second shaft hole, thereby ensuring that the stirring pin retraction shaft inside the second shaft hole is coaxially aligned with the hollow motor rotor shaft. The first shaft hole and the stirring head... The rear part of the clamping handle matches the outer part, ensuring that the rear part of the stirring head clamping handle is within the first shaft hole and coaxially centered with the first shaft hole, thereby ensuring that the stirring head clamping handle within the first shaft hole is coaxially centered with the hollow motor rotor shaft; the stirring head clamping handle is provided with a through shaft hole inside, including a third shaft hole located at the front of the stirring head clamping handle and a fourth shaft hole located at the rear of the stirring head clamping handle, the third shaft hole and the fourth shaft hole are connected to form a through shaft hole, the third shaft hole, the fourth shaft hole and the stirring head clamping handle are coaxially centered; the third shaft hole matches the rear part of the shoulder, ensuring that the rear part of the shoulder is within the third shaft hole and The shaft shoulder is aligned with the third shaft hole along the same axial centerline, ensuring that the shoulder within the third shaft hole is aligned with the stirring head clamping handle along the same axial centerline. The shoulder has a through-hole, including a fifth shaft hole at the front and a sixth shaft hole at the rear, which are connected to form a through-hole. The fifth and sixth shaft holes are aligned with the shoulder along the same axial centerline. The retraction motor rotor shaft, installed in the second shaft hole, passes through the fourth shaft hole and inserts into the sixth shaft hole at its front end, and extends out of the second shaft hole and connects to the rotation separation mechanism at its rear end. The front exterior of the stirring needle retraction shaft aligns with both the fourth and sixth shaft holes. The stirring pin is fitted to ensure that the front part of the retraction shaft is inside the fourth and sixth shaft holes and is coaxial with the fourth and sixth shaft holes respectively, thereby ensuring that the stirring pin retraction shaft inside the fourth and sixth shaft holes is coaxial with the stirring head clamping handle and the shaft shoulder respectively; the front part of the stirring pin is matched with the fifth shaft hole, ensuring that the front part of the stirring pin is inside the fifth shaft hole and is coaxial with the fifth shaft hole, thereby ensuring that the stirring pin inside the fifth shaft hole is coaxial with the shaft shoulder; the stirring pin installed in the fifth shaft hole has its front end extending out of the fifth shaft hole, and its rear end is inserted into the stirring pin retraction shaft from the front end of the stirring pin retraction shaft and threadedly connected to the stirring pin retraction shaft.

[0013] Furthermore, both the first shaft hole and the rear outer part of the stirring head clamping handle are 7:24 conical surfaces; the 7:24 conical surface includes two coaxial base circles and a conical surface connecting the two base circles, and the ratio of the diameter difference between the two base circles to the height of the conical surface is 7:24; the rear part of the stirring head clamping handle is fitted and connected inside the first shaft hole and is coaxial with the center line of the first shaft hole.

[0014] Furthermore, an adjusting shim is provided between the stirring head clamping handle and the end face of the hollow motor rotor shaft. The stirring head clamping handle and the hollow motor rotor shaft are coaxially fixed by screws passing through the stirring head clamping handle, the adjusting shim and the hollow motor rotor shaft. The shaft shoulder and the stirring head clamping handle are coaxially fixed by end face screws and side screws.

[0015] Furthermore, symmetrical end-face keys are provided on the stirring head clamping handle within the first shaft hole, and an end-face keyway is provided at the corresponding position within the first shaft hole. The end-face keys and end-face keyways are matched, and the stirring head clamping handle within the first shaft hole is connected to the first shaft hole through the end-face keys and end-face keyways, achieving stable transmission of high torque from the hollow motor rotor shaft to the stirring head clamping handle. Symmetrical shoulder guide keys are provided on the shoulder within the third shaft hole, and a shoulder guide keyway is provided at the corresponding position within the third shaft hole. The shoulder guide keys and shoulder guide keyways are matched, and the stirring head clamping handle within the third shaft hole is connected to the third shaft hole through the shoulder guide keys and shoulder guide keyways, achieving stable transmission of high torque from the hollow motor rotor shaft to the shoulder. Symmetrical stirring needle guide keys are provided on the stirring needle within the fifth shaft hole, and a stirring needle guide keyway is provided at the corresponding position within the fifth shaft hole. The stirring needle guide keys and stirring needle guide keyways are matched. The stirring pin in the fifth shaft hole is connected to the fifth shaft hole via a stirring pin guide key and a stirring pin guide keyway, which enables the stable transmission of high torque from the hollow motor rotor shaft to the stirring pin and ensures that the stirring pin has the freedom to move along the axial centerline of the hollow motor rotor shaft within the shoulder. Symmetrical stirring pin retraction shaft guide keys are provided on the stirring pin retraction shaft in the fourth shaft hole, and corresponding stirring pin retraction shaft guide keyways are provided at the same positions within the fourth shaft hole. The stirring pin retraction shaft guide keys and the stirring pin retraction shaft guide keyways are matched. The stirring pin retraction shaft in the fourth shaft hole is connected to the fourth shaft hole via a stirring pin retraction shaft guide key and a stirring pin retraction shaft guide keyway, which enables the stable transmission of high torque from the hollow motor rotor shaft to the stirring pin and ensures that the stirring pin retraction shaft has the freedom to move along the axial centerline of the hollow motor rotor shaft within the stirring head clamping handle. The stirring pin retraction shaft in the sixth shaft hole is clearance-fitted within the sixth shaft hole.

[0016] Furthermore, the stirring head clamping handle is compatible with conventional stirring heads for heavy-duty friction stir welding; the conventional stirring head for heavy-duty friction stir welding is mounted on the front end of the heavy-duty friction stir welding spindle via the stirring head clamping handle, and the rotation of the stirring head clamping handle is controlled by the heavy-duty friction stir welding spindle to drive the conventional stirring head for heavy-duty friction stir welding to rotate synchronously.

[0017] Beneficial technical effects of the present invention:

[0018] The heavy-duty friction stir welding retractable stirring head of this invention achieves high-torque synchronous output transmission for friction stir welding through structural optimization. The stirring pin head has a spherical cross-section with a tapered thread, resulting in more thorough material mixing, high-quality weld joints, and a long fatigue life for the stirring pin. The universal interface design between the heavy-duty friction stir welding retractable stirring head and the conventional stirring head allows for rapid switching between the two, improving welding efficiency. When installed and matched with a heavy-duty friction stir welding spindle with stirring pin retraction function, continuous and stable retraction during the welding process eliminates the keyhole in the weld circumference, enabling high-quality, efficient, reliable, and automated welding of fuel tanks for next-generation manned launch vehicles. Attached Figure Description

[0019] Figure 1 A schematic diagram of the connection structure between the heavy-duty friction stir welding spindle slide box, the heavy-duty friction stir welding spindle with stirring needle retraction function, and the heavy-duty friction stir welding retraction head.

[0020] Figure 2 A schematic diagram of the connection structure between a heavy-duty friction stir welding spindle with stirring needle retraction function and a heavy-duty friction stir welding retraction head.

[0021] Figure 3 A schematic diagram of the cross-sectional structure of the connection between the heavy-duty friction stir welding spindle with stirring needle retraction function and the heavy-duty friction stir welding retraction head.

[0022] Figure 4 A schematic diagram of the connection structure between the retractable stirring head and the heavy-duty friction stir welding spindle for heavy-duty friction stir welding.

[0023] Figure 5 For heavy-duty friction stir welding, the retractable stirring head is connected longitudinally to the heavy-duty friction stir welding spindle. Figure 4 Schematic diagram of the cross-sectional structure at the location of the key on the middle end face;

[0024] Figure 6 For heavy-duty friction stir welding, the retractable stirring head is connected to the heavy-duty friction stir welding spindle laterally. Figure 4 Schematic diagram of the cross-sectional structure of the guide key on the central shoulder;

[0025] Figure 7 This is a schematic diagram of the connection structure between the stirring needle and the shaft shoulder;

[0026] Figure 8 View of the threaded end of the stirring needle;

[0027] Figure 9 This is a diagram showing the connection between the stirring needle and the shaft shoulder.

[0028] Figure 10This is a schematic diagram of the stirring needle structure;

[0029] Figure 11 View of the stirring needle head from direction C;

[0030] Figure 12 This is a schematic diagram of the cross-sectional structure of the stirring needle head along direction AA.

[0031] Figure 13 A schematic diagram of the cross-sectional structure of the keyway guiding the stirring pin along the BB direction;

[0032] Figure 14 A schematic diagram of the cross-sectional structure of the connection between the stirring head clamping handle and the heavy-duty friction-welded retractable stirring head.

[0033] Figure 15 This is a schematic diagram of the cross-sectional structure of the connection between the stirring head clamp and the conventional stirring head, which is subjected to heavy-duty friction welding.

[0034] In the figure, 1-Heavy-duty friction stir welding spindle slide box, 2-Heavy-duty friction stir welding spindle, 3-Heavy-duty friction stir welding retractable stirring head, 4-Heavy-duty friction stir welding stirring needle retraction device, 5-Shoulder, 6-Stirring needle, 7-Shoulder guide key, 8-Stirring needle guide key, 9-Stirring head clamping handle, 10-End face key, 11-Adjusting shim, 12-Stirring needle retraction shaft, 13-Hollow motor spindle, 14-Stirring needle retraction shaft guide key, 15-First sliding bearing, 16 17-Second sliding bearing; 18-First tapered roller bearing assembly; 19-Guide shaft guide key; 20-Guide shaft; 21-Guide bushing; 22-Second tapered roller bearing assembly; 23-Retracting planetary screw; 24-Retracting motor rotor shaft; 25-Retracting planetary screw guide needle roller bearing; 26-Cylindrical roller bearing; 27-Retracting motor encoder; 28-Heavy-duty friction stir welding conventional stirring head; 29-Heavy-duty friction stir welding conventional stirring head connecting sleeve. Detailed Implementation

[0035] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] In the description of this invention, it should be noted that the terms "front end", "rear end", "front part", "rear part", "external", "internal", etc., 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 invention 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, they should not be construed as limiting this invention.

[0037] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be interpreted as indicating or implying relative importance.

[0038] See Figure 1-15 This embodiment provides a heavy-duty friction stir welding (FSM) retractable stirring head 3 suitable for welding closed circumferential seams of thick, high-strength aluminum alloy tank bodies, such as fuel tank bodies for manned launch vehicles. It is installed and cooperates with a heavy-duty friction stir welding spindle with stirring pin retraction function. Through continuous and stable retraction of the stirring pin during the welding process, the keyhole of the weld circumferential seam is eliminated, achieving high-quality, efficient, reliable, and automated welding of fuel tank bodies for next-generation manned launch vehicles. The heavy-duty friction stir welding spindle with stirring pin retraction function includes a heavy-duty friction stir welding spindle 2 and a heavy-duty friction stir welding stirring pin retraction device 4 installed at the rear end of the spindle 2. Both the heavy-duty friction stir welding spindle 2 and the stirring pin retraction device 4 are installed in the heavy-duty friction stir welding spindle slide box 1 at the end of the friction stir welding actuator for closed circumferential seams of thick, high-strength aluminum alloy tank bodies. The front end of the heavy-duty friction stir welding spindle 2 extends out of the slide box 1. The heavy-duty friction stir welding retractable stirring head 3 is installed at the front end of the heavy-duty friction stir welding spindle 2.

[0039] The heavy-duty friction stir welding retractable stirring head 3 described in this embodiment includes a split-structure stirring needle 6 and a shoulder 5. The head of the stirring needle 6 is a spherical cross-section with a tapered thread. The stirring needle 6 and the shoulder 5 are rotated synchronously by the heavy-duty friction stir welding spindle 2. The stirring needle 6 is retracted linearly into the shoulder 5 while rotating synchronously with the shoulder 5 by the heavy-duty friction stir welding stirring needle retraction device 4.

[0040] The head of the stirring pin 6 has a spherical cross-section with a tapered thread, which makes the material more thoroughly mixed, resulting in better tensile mechanical properties and elongation of the weld joint, and a longer fatigue life for the stirring pin 6.

[0041] In this embodiment, three conical threads are evenly distributed on the spherical cross-section of the head of the stirring needle 6, and the three conical threads have the same depth.

[0042] The heavy-duty friction stir welding spindle 2 described in this embodiment includes a heavy-duty friction stir welding spindle housing and a hollow motor installed inside the housing. The hollow motor includes a hollow motor rotor and a hollow motor rotor shaft 13. The hollow motor rotor is axially fixedly connected to the hollow motor rotor shaft 13. The rotational torque of not less than 800 Nm output by the hollow motor rotor to the hollow motor rotor shaft 13 is synchronously transmitted to the shaft shoulder 5 and the stirring needle 6, causing the shaft shoulder 5 and the stirring needle 6 to rotate synchronously. The heavy-duty friction stir welding stirring needle retraction device 4 includes a heavy-duty friction stir welding stirring needle retraction device housing, a rotation separation mechanism and a planetary screw servo drive mechanism installed inside the housing, and a stirring needle retraction shaft 12. The stirring needle retraction shaft 12 is coaxially installed inside the hollow motor rotor shaft 13, with its front end extending out of the hollow motor rotor shaft 13 and inserted from the rear end of the shaft shoulder 5. Shoulder 5 extends from the rear end of the hollow motor rotor shaft 13 and is sequentially connected to the rotary separation mechanism and the planetary screw servo drive mechanism. The stirring needle 6 is coaxially installed inside the shoulder 5, with its front end extending out of the shoulder 5 and its rear end inserted into the stirring needle retraction shaft 12. The stirring needle 6 has a degree of freedom to move along the axial centerline of the hollow motor rotor shaft 13 within the shoulder 5, referred to as the first degree of freedom. The stirring needle retraction shaft 12 has a degree of freedom to move along the axial centerline of the hollow motor rotor shaft 13 within the hollow motor rotor shaft 13, referred to as the second degree of freedom. The first degree of freedom and the second degree of freedom are consistent. The planetary screw servo drive mechanism, in cooperation with the rotary separation mechanism, drives the stirring needle retraction shaft 12 to move along the axial centerline of the hollow motor rotor shaft 13 within the hollow motor rotor shaft 13, thereby causing the stirring needle 6 to retract into the shoulder 5 along the axial centerline of the hollow motor rotor shaft 13.

[0043] The heavy-duty friction stir welding retractable stirring head 3 described in this embodiment also includes a stirring head clamping handle 9. The rear end of the stirring head clamping handle 9 is inserted into the front end of the hollow motor rotor shaft 13; the rear end of the shaft shoulder 5 is inserted into the stirring head clamping handle 9 from the front end; and the front end of the stirring needle retraction shaft 12 is inserted into the shaft shoulder 5 from both the rear end of the stirring head clamping handle 9 and the rear end of the shaft shoulder 5. The rotational torque output by the hollow motor rotor to the hollow motor rotor shaft is transmitted to the stirring head clamping handle, causing the stirring head clamping handle 9 to rotate, thereby causing the shaft shoulder 5 and the stirring needle 6 to rotate synchronously.

[0044] In this embodiment, the hollow motor rotor shaft 13 has a through shaft hole inside, including a first shaft hole at the front of the hollow motor rotor shaft 13 and a second shaft hole at the rear of the hollow motor rotor shaft 13. The first shaft hole and the second shaft hole communicate to form a through shaft hole, and the first shaft hole, the second shaft hole, and the hollow motor rotor shaft 13 are coaxially centered. The rear of the stirring needle retraction shaft 12 matches the second shaft hole, ensuring that the rear of the stirring needle retraction shaft 12 is inside the second shaft hole and coaxially centered with the second shaft hole, thereby ensuring that the stirring needle retraction shaft 12 inside the second shaft hole is coaxially centered with the hollow motor rotor shaft 13. The first shaft hole The stirring head clamping handle 9 is matched with the rear part of the outside, ensuring that the rear part of the stirring head clamping handle 9 is within the first shaft hole and coaxial with the first shaft hole, thereby ensuring that the stirring head clamping handle 9 within the first shaft hole is coaxial with the hollow motor rotor shaft 13; the stirring head clamping handle 9 is provided with a through shaft hole, including a third shaft hole provided in the front part of the stirring head clamping handle 9 and a fourth shaft hole provided in the rear part of the stirring head clamping handle 9, the third shaft hole and the fourth shaft hole are connected to form a through shaft hole, and the third shaft hole, the fourth shaft hole and the stirring head clamping handle 9 are coaxial with the third shaft hole; the third shaft hole matches the rear part of the outer part of the shoulder 5, ensuring that the rear part of the shoulder 5 is within the third shaft hole. The shoulder 5 and the stirring head clamping handle 9 are aligned axially and coaxially with the third shaft hole, thus ensuring that the shoulder 5 and the stirring head clamping handle 9 are aligned axially. The shoulder 5 has a through shaft hole, including a fifth shaft hole at the front and a sixth shaft hole at the rear. The fifth and sixth shaft holes are connected to form a through shaft hole, and the fifth and sixth shaft holes are aligned axially with the shoulder 5. The retraction motor rotor shaft 12, installed in the second shaft hole, has its front end passing through the fourth shaft hole and inserting into the sixth shaft hole, and its rear end extending out of the second shaft hole and connecting to the rotating separation mechanism. The front exterior of the stirring needle retraction shaft 12 matches the fourth and sixth shaft holes respectively, ensuring... The front part of the stirring needle retraction shaft 12 is located within the fourth and sixth shaft holes and is coaxial with the fourth and sixth shaft holes respectively, thereby ensuring that the stirring needle retraction shaft 12 within the fourth and sixth shaft holes is coaxial with the stirring head clamping handle 9 and the shaft shoulder 5 respectively; the front part of the stirring needle 6 is matched with the fifth shaft hole, ensuring that the front part of the stirring needle 6 is located within the fifth shaft hole and is coaxial with the fifth shaft hole, thereby ensuring that the stirring needle 6 within the fifth shaft hole is coaxial with the shaft shoulder 5; the stirring needle 6 installed in the fifth shaft hole has its front end extending out of the fifth shaft hole, and its rear end is inserted into the stirring needle retraction shaft 12 from the front end of the stirring needle retraction shaft 12 and threadedly connected to the stirring needle retraction shaft 12.

[0045] In this embodiment, both the first shaft hole and the rear outer part of the stirring head clamping handle 9 are 7:24 conical surfaces. The 7:24 conical surface includes two coaxial base circles and a conical surface connecting the two base circles. The ratio of the diameter difference between the two base circles to the height of the conical surface is 7:24. The rear part of the stirring head clamping handle 9 is fitted into the first shaft hole and is coaxial with the first shaft hole. The stirring head clamping handle 9 and the hollow motor rotor shaft 13 are coaxial through the 7:24 conical surface fit.

[0046] In this embodiment, an adjusting shim 11 is provided between the stirring head clamping handle 9 and the end face of the hollow motor rotor shaft 13. The stirring head clamping handle 9 and the hollow motor rotor shaft 13 are coaxially fixed by screws passing through the stirring head clamping handle 9, the adjusting shim 11 and the hollow motor rotor shaft 13. The shaft shoulder 5 and the stirring head clamping handle 9 are coaxially fixed by end face screws and side screws.

[0047] In this embodiment, end face keys 10 are symmetrically provided on the stirring head clamping handle 9 in the first shaft hole, and end face keyways are provided at corresponding positions of the end face keys 10 in the first shaft hole. The end face keys 10 and end face keyways are matched. The stirring head clamping handle 9 in the first shaft hole is connected to the first shaft hole through the end face keys 10 and end face keyways, so as to realize the stable transmission of the large torque of the hollow motor rotor shaft 13 to the stirring head clamping handle 9.

[0048] A shoulder guide key 7 is symmetrically provided on the shoulder 5 inside the third shaft hole, and a shoulder guide key groove is provided at the corresponding position of the shoulder guide key 7 inside the third shaft hole. The shoulder guide key 7 and the shoulder guide key groove are matched. The stirring head clamping handle 9 inside the third shaft hole is connected to the third shaft hole through the shoulder guide key 7 and the shoulder guide key groove, so as to realize the stable transmission of the large torque of the hollow motor rotor shaft 13 to the shoulder 5.

[0049] A stirring needle guide key 8 is symmetrically provided on the stirring needle 6 inside the fifth shaft hole. A stirring needle guide key groove is provided at the corresponding position of the stirring needle guide key 8 inside the fifth shaft hole. The stirring needle guide key 8 and the stirring needle guide key groove are matched. The stirring needle 6 inside the fifth shaft hole is connected to the fifth shaft hole through the stirring needle guide key 8 and the stirring needle guide key groove, so as to realize the stable transmission of the large torque of the hollow motor rotor shaft 13 to the stirring needle 6, and to ensure that the stirring needle 6 has the freedom to move along the axial center line of the hollow motor rotor shaft 13 within the shoulder 5.

[0050] Symmetrical guide keys 14 for the stirring needle retraction shaft 12 are provided on the stirring needle retraction shaft 12 in the fourth shaft hole. A guide keyway for the stirring needle retraction shaft is provided at the corresponding position of the guide key in the fourth shaft hole. The guide key 14 and the guide keyway for the stirring needle retraction shaft are matched. The stirring needle retraction shaft 12 in the fourth shaft hole is connected to the fourth shaft hole through the guide key 14 and the guide keyway for the stirring needle retraction shaft, so as to realize the stable transmission of the large torque of the hollow motor rotor shaft 13 to the stirring needle 6, and to ensure that the stirring needle retraction shaft 12 has the freedom to move along the axial centerline of the hollow motor rotor shaft 13 in the stirring head clamping handle 9. The stirring needle retraction shaft 12 in the sixth shaft hole is clearance-fitted in the sixth shaft hole.

[0051] The stirring head clamping handle 9 described in this embodiment is compatible with the conventional stirring head 28 for heavy-duty friction stir welding. The conventional stirring head 28 is mounted on the front end of the heavy-duty friction stir welding spindle 2 via the stirring head clamping handle 9. The rotation of the stirring head clamping handle 9, controlled by the heavy-duty friction stir welding spindle 2, causes the conventional stirring head 28 to rotate synchronously. The conventional stirring head 28 is connected to the stirring head clamping handle 9 via a conventional stirring head connecting sleeve 29. The rear end of the conventional stirring head 28 is inserted into the conventional stirring head connecting sleeve 29 from its front end. The conventional stirring head connecting sleeve 29 matches the third shaft hole, and the sleeve is inserted into the third shaft hole and coaxially fixed with it using end face screws and side screws.

[0052] The stirring head clamping handle 9 described in this embodiment is produced by a matching grinding process with the inner conical hole of the hollow motor rotor shaft (13). During the matching grinding process, the coloring method is used to check that the contact area is not less than 90% to ensure that the rotational coaxiality is within 0.008.

[0053] The installation of the heavy-duty friction stir welding retractable stirring head 3 includes the following steps: Insert the rear end of the stirring pin 6 into the front end of the stirring pin retraction shaft 12 and thread it onto the shaft; rotate the stirring pin 6 to loosen the threaded connection between the stirring pin 6 and the stirring pin retraction shaft 12, aligning the stirring pin guide key 8 with the stirring pin guide keyway; insert the rear end of the shoulder 5 into the third shaft hole, axially fixing the shoulder 5 within the third shaft hole using end face screws and side screws, aligning the shoulder guide key 7 with the shoulder guide key; insert the rear end of the stirring head clamping handle 9 into the first shaft hole, axially fixing the stirring head clamping handle 9 within the first shaft hole using screws and adjusting shims 11, aligning the end face key 10 with the end face keyway; adjust the stirring pin retraction shaft 12 to align the cylindrical step at the front end of the stirring pin 6 with the opening of the shoulder 5, thus completing the installation of the heavy-duty friction stir welding retractable stirring head 3.

[0054] In this embodiment, to ensure that the stirring needle retraction shaft 12 moves along the axial centerline of the hollow motor rotor shaft 13 within the hollow motor rotor shaft 13, thereby driving the stirring needle 6 to move along the axial centerline of the hollow motor rotor shaft 13, a guide bushing is provided for the stirring needle retraction shaft 12 to move along the axial centerline of the hollow motor rotor shaft 13. The guide bushing for the stirring needle retraction shaft 12 to move along the axial centerline of the hollow motor rotor shaft 13 includes a first sliding bearing 15 disposed at the front end of the second shaft hole and a second sliding bearing 16 disposed at the rear end of the second shaft hole. The first sliding bearing 15 and the second sliding bearing 16 are respectively in contact with the inner wall of the hollow motor rotor shaft 13 and the outer wall of the stirring needle retraction shaft 12. The first sliding bearing 15, the second sliding bearing 16 and the hollow motor rotor shaft 13 share the same axial centerline. The first sliding bearing 15 and the second sliding bearing 16 serve as guide bushings for the movement of the stirring needle retraction shaft 12 along the axial centerline of the hollow motor rotor shaft 13, ensuring that the stirring needle retraction shaft 12 moves along the axial centerline of the hollow motor rotor shaft 13, thereby driving the stirring needle 6 to move along the axial centerline of the hollow motor rotor shaft 13.

[0055] In this embodiment, the rotating separation mechanism includes a first tapered roller bearing assembly 17, a guide shaft 19, a guide bushing 20, and a second tapered roller bearing assembly 21. The guide bushing 20 is detachably fixed inside the front part of the housing of the heavy-duty friction stir welding agitator needle retraction device. The front end of the front part of the heavy-duty friction stir welding agitator needle retraction device housing is detachably fixed to the rear end of the heavy-duty friction stir welding main shaft housing, and a space is left between the front part of the heavy-duty friction stir welding agitator needle retraction device housing and the heavy-duty friction stir welding main shaft housing. The rear end of the front part of the heavy-duty friction stir welding agitator needle retraction device housing is detachably fixed to the front end of the rear part of the heavy-duty friction stir welding agitator needle retraction device housing. A space is left between the front part and the rear part of the housing of the heavy-duty friction stir welding stirring needle retraction device; the guide shaft 19 and the hollow motor rotor shaft 13 share the same axial centerline; the guide shaft 19 has a degree of freedom to move along the axial centerline of the hollow motor rotor shaft 13 within the guide bushing 20, referred to as the third degree of freedom; the third degree of freedom is consistent with the first degree of freedom; the rear end of the stirring needle retraction shaft 12 is inserted into the guide shaft 19 from the front end of the guide shaft 19; the front end of the guide shaft 19 and the stirring needle retraction shaft 12 are detachably and fixedly connected by a connector; the stirring needle retraction shaft 12 and the guide shaft 19 within the guide shaft 19 are connected by a first tapered roller bearing assembly 17;

[0056] The planetary screw servo drive mechanism includes a retraction motor 24, a retraction planetary screw 22, and a retraction planetary screw nut. The retraction motor 24 is installed inside the rear part of the housing of the heavy-duty stirring friction welding stirring needle retraction device, and includes a retraction motor rotor and a retraction motor rotor shaft 23. The retraction planetary screw 22 and the retraction motor rotor shaft 23 are coaxially aligned. The front part of the retraction planetary screw 22 is detachably and fixedly connected to the rear end of the guide shaft 19 via a connector, and the rear end is inserted into the retraction motor rotor shaft 23. The retraction planetary screw nut is threaded onto the retraction planetary screw 22, and the retraction planetary screw nut is inside the retraction motor rotor shaft 23 and detachably and fixedly connected to the retraction motor rotor shaft 23. The retraction motor rotor shaft 23 and the retraction motor... The rotor is axially fixed, and the return motor rotor outputs rotational torque to the return motor rotor shaft 23, driving the return planetary wire nut to rotate; the front of the return motor rotor shaft 23 is provided with a second tapered roller bearing assembly 21, which is in contact with the rear inner wall of the heavy-duty stirring friction welded stirring needle return device housing and the front outer wall of the return motor rotor shaft 23 respectively; the second tapered roller bearing assembly 21 realizes the axial and radial positioning of the return motor rotor shaft 23, ensuring that the return motor rotor shaft 23 and the hollow motor rotor shaft 13 share the same axial centerline, and at the same time, the second tapered roller bearing assembly 21 bears the forging force of the stirring needle 6 moving along the axial centerline of the hollow motor rotor shaft 13;

[0057] The first tapered roller bearing assembly 17, the guide shaft 19, and the second tapered roller bearing assembly 21 cooperate to separate the rotational motion of the stirring needle return shaft 12 while ensuring that it can withstand the forging force that causes the stirring needle return shaft 12 to move along the axial centerline of the hollow motor rotor shaft 13. In this way, the return planetary screw 22 moves along the axial centerline of the hollow motor rotor shaft 13 under the rotation of the return planetary screw nut, which drives the guide shaft 19 to move along the axial centerline of the hollow motor rotor shaft 13 within the guide bushing 20. This, in turn, drives the stirring needle return shaft 12 to move along the axial centerline of the hollow motor rotor shaft 13 within the hollow motor rotor shaft 13, thus enabling the stirring needle 6 to move along the axial centerline of the hollow motor rotor shaft 13 within the shoulder 5.

[0058] In this embodiment, the front part of the retractable planetary screw 22 is guided by the guide shaft 19 and the guide bushing 20; the rear part of the retractable motor rotor shaft 23 is provided with a retractable planetary screw guide needle roller bearing 25, which is in contact with the inner wall of the retractable motor rotor shaft 23 and the outer wall of the retractable planetary screw 22 respectively; the retractable planetary screw 22 is guided in the retractable motor rotor shaft 23 by the retractable planetary screw guide needle roller bearing 25, and the tolerance of the retractable planetary screw 22 ensures that the retractable planetary screw 22 has a degree of freedom to move along the axial centerline of the hollow motor rotor shaft 13 in the retractable planetary screw guide needle roller bearing 25, which is called the fourth degree of freedom; the fourth degree of freedom is consistent with the first degree of freedom.

[0059] In this embodiment, the guide shaft 19 is inside the guide bushing 20 and connected to the guide bushing 20 via the guide shaft guide key 18, ensuring that the guide shaft 19 and the hollow motor rotor shaft 13 are aligned along the same axial centerline and that the guide shaft 19 has the freedom to move along the axial centerline of the hollow motor rotor shaft 13 within the guide bushing 20.

[0060] In this embodiment, a set of cylindrical roller bearings 26 are configured at the rear end of the retraction motor rotor shaft 23 to bear radial loads, ensuring that the retraction motor rotor shaft 23 and the hollow motor rotor shaft 13 are on the same axial centerline, resulting in high retraction accuracy and strong axial load bearing capacity.

[0061] In this embodiment, the planetary screw servo drive mechanism further includes a retraction motor encoder 27; the retraction motor encoder 27 is connected to the retraction motor rotor shaft 23 via a corrugated coupling, enabling precision transmission without backlash; the retraction motor encoder 27 is an integrated high-precision encoder that accurately measures the rotational torque of the retraction motor rotor shaft 23, thereby precisely controlling the rotational torque range of the retraction motor rotor shaft 23 so that the degree of freedom of the retraction planetary screw 22 moving along the axial centerline of the hollow motor rotor shaft 13 is consistent with the first degree of freedom, thereby precisely controlling the displacement of the stirring needle 6 retracting into the shoulder 5 along the axial centerline of the hollow motor rotor shaft 13.

[0062] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A heavy-duty retractable stirring head for friction stir welding, installed at the front end of a heavy-duty retractable friction stir welding spindle with a retractable stirring pin function, characterized in that, The system includes a split-structure stirring needle (6) and a shoulder (5). The head of the stirring needle (6) is a spherical cross-section with a tapered thread. The stirring needle (6) is controlled by a heavy-duty stirring friction welding spindle with stirring needle retraction function to perform a linear retraction motion inward towards the shoulder in a state of synchronous rotation with the shoulder (5). The heavy-duty stirring friction welding spindle with stirring needle retraction function includes a heavy-duty stirring friction welding spindle (2) and a heavy-duty stirring friction welding stirring needle retraction device (4) installed at the rear end of the heavy-duty stirring friction welding spindle (2). The heavy-duty stirring friction welding retractionable stirring head (3) is installed at the front end of the heavy-duty stirring friction welding spindle (2). The stirring needle (6) is controlled by the heavy-duty stirring friction welding spindle (2) to rotate synchronously with the shoulder (5), and the stirring needle (6) is controlled by the heavy-duty stirring friction welding stirring needle retraction device (4) to perform a linear retraction motion inward towards the shoulder in a state of synchronous rotation with the shoulder (5). The heavy-duty friction stir welding spindle (2) includes a hollow motor, which includes a hollow motor rotor and a hollow motor rotor shaft (13). The hollow motor rotor is axially fixed to the hollow motor rotor shaft (13). The rotational torque output by the hollow motor rotor to the hollow motor rotor shaft (13) is synchronously transmitted to the shaft shoulder (5) and the stirring needle (6), causing the shaft shoulder (5) and the stirring needle (6) to rotate synchronously. The heavy-duty friction stir welding stirring needle retraction device (4) includes a rotation separation mechanism and a planetary screw servo drive mechanism, as well as a stirring needle retraction shaft (12). The stirring needle retraction shaft (12) is coaxially installed inside the hollow motor rotor shaft (13), with its front end extending out of the hollow motor rotor shaft (13) and inserted into the shaft shoulder (5) from the rear end of the shaft shoulder (5). Its rear end extends out of the hollow motor rotor shaft (13) and is connected to the rotation separation mechanism and the planetary screw servo drive mechanism in sequence. The stirring needle (6) is coaxially installed inside the shoulder (5), with its front end extending out of the shoulder (5) and its rear end inserted into the stirring needle retraction shaft (12). The stirring needle (6) has a degree of freedom to move along the axial centerline of the hollow motor rotor shaft (13) inside the shoulder (5), which is called the first degree of freedom. The stirring needle retraction shaft (12) has a degree of freedom to move along the axial centerline of the hollow motor rotor shaft (13) inside the hollow motor rotor shaft (13), which is called the second degree of freedom. The first degree of freedom is consistent with the second degree of freedom. The planetary screw servo drive mechanism, in cooperation with the rotation separation mechanism, drives the stirring needle retraction shaft (12) to move along the axial centerline of the hollow motor rotor shaft (13) inside the hollow motor rotor shaft (13), thereby driving the stirring needle (6) to retract into the shoulder (5) along the axial centerline of the hollow motor rotor shaft (13).

2. The heavy-duty friction stir welding retractable stirring head according to claim 1, characterized in that, The stirring needle (6) has three tapered threads evenly distributed on its spherical cross-section, and the three tapered threads have the same depth.

3. The heavy-duty friction stir welding retractable stirring head according to claim 1, characterized in that, The heavy-duty friction stir welding retractable stirring head (3) also includes a stirring head clamping handle (9), the rear end of which is inserted into the hollow motor rotor shaft (13) from the front end of the hollow motor rotor shaft (13); the rear end of the shaft shoulder (5) is inserted into the stirring head clamping handle (9) from the front end of the stirring head clamping handle (9); the front end of the stirring needle retraction shaft (12) is inserted into the shaft shoulder (5) from the rear end of the stirring head clamping handle (9) and the rear end of the shaft shoulder (5) in sequence.

4. The heavy-duty friction stir welding retractable stirring head according to claim 3, characterized in that, The hollow motor rotor shaft (13) has a through shaft hole inside, including a first shaft hole at the front of the hollow motor rotor shaft (13) and a second shaft hole at the rear of the hollow motor rotor shaft (13). The first shaft hole and the second shaft hole are connected to form a through shaft hole. The first shaft hole, the second shaft hole, and the hollow motor rotor shaft (13) are coaxially aligned. The rear of the stirring needle retraction shaft (12) matches the second shaft hole, ensuring that the rear of the stirring needle retraction shaft (12) is inside the second shaft hole and is coaxially aligned with the second shaft hole, thereby ensuring that the stirring needle retraction shaft (12) inside the second shaft hole is coaxially aligned with the hollow motor rotor shaft (13). The first shaft hole and the stirring head clamping handle ( 9) The rear part of the outer part matches, ensuring that the rear part of the stirring head clamping handle (9) is in the first shaft hole and coaxially aligned with the first shaft hole, thereby ensuring that the stirring head clamping handle (9) in the first shaft hole is coaxially aligned with the hollow motor rotor shaft (13); the stirring head clamping handle (9) is provided with a through shaft hole, including a third shaft hole provided in the front part of the stirring head clamping handle (9) and a fourth shaft hole provided in the rear part of the stirring head clamping handle (9), the third shaft hole and the fourth shaft hole are connected to form a through shaft hole, the third shaft hole, the fourth shaft hole and the stirring head clamping handle (9) are coaxially aligned; the third shaft hole matches the rear part of the outer part of the shoulder (5), ensuring that the rear part of the shoulder (5) is in the third shaft hole and coaxially aligned with the third shaft hole. The shaft shoulder (5) and the stirring head clamping handle (9) are aligned along the same axis. The shaft shoulder (5) has a through shaft hole, including a fifth shaft hole at the front of the shaft shoulder (5) and a sixth shaft hole at the rear of the shaft shoulder (5). The fifth shaft hole and the sixth shaft hole are connected to form a through shaft hole. The fifth shaft hole, the sixth shaft hole and the shaft shoulder (5) are aligned along the same axis. The retraction motor rotor shaft (12) installed in the second shaft hole passes through the fourth shaft hole and is inserted into the sixth shaft hole. The rear end extends out of the second shaft hole and is connected to the rotating separation mechanism. The front exterior of the stirring needle retraction shaft (12) matches the fourth shaft hole and the sixth shaft hole respectively, ensuring that the stirring needle retraction shaft... (12) The front part is in the fourth shaft hole and the sixth shaft hole and is coaxial with the fourth shaft hole and the sixth shaft hole respectively, so as to ensure that the stirring needle retraction shaft (12) in the fourth shaft hole and the sixth shaft hole is coaxial with the stirring head clamping handle (9) and the shaft shoulder (5) respectively; the front part of the stirring needle (6) is matched with the fifth shaft hole, so as to ensure that the front part of the stirring needle (6) is in the fifth shaft hole and is coaxial with the fifth shaft hole, so as to ensure that the stirring needle (6) in the fifth shaft hole is coaxial with the shaft shoulder (5); the stirring needle (6) installed in the fifth shaft hole has its front end extending out of the fifth shaft hole, and its rear end is inserted into the stirring needle retraction shaft (12) from the front end of the stirring needle retraction shaft (12) and threadedly connected to the stirring needle retraction shaft (12).

5. The heavy-duty friction stir welding retractable stirring head according to claim 4, characterized in that, The rear part of the first shaft hole and the stirring head clamp (9) are both 7:24 conical surfaces; the 7:24 conical surface includes two coaxial bottom circles and a conical surface connecting the two bottom circles, and the ratio of the diameter difference between the two bottom circles to the height of the conical surface is 7:24; the rear part of the stirring head clamp (9) is fitted and connected inside the first shaft hole and is coaxial with the center line of the first shaft hole.

6. The heavy-duty friction stir welding retractable stirring head according to claim 4, characterized in that, A face key (10) is symmetrically provided on the stirring head holder (9) in the first shaft hole. A face keyway is provided at the corresponding position of the face key (10) in the first shaft hole. The face key (10) matches the face keyway. The stirring head holder (9) in the first shaft hole is connected to the first shaft hole through the face key (10) and the face keyway. A shoulder guide key (7) is symmetrically provided on the shoulder (5) in the third shaft hole. A shoulder guide keyway is provided at the corresponding position of the shoulder guide key (7) in the third shaft hole. The shoulder guide key (7) matches the shoulder guide keyway. The stirring head holder (9) in the third shaft hole is connected to the third shaft hole through the shoulder guide key (7) and the shoulder guide keyway. A stirring needle guide key (8) is symmetrically provided on the stirring needle (6) in the fifth shaft hole. A stirring needle guide keyway is provided at the corresponding position of the stirring needle guide key (8) in the fifth shaft hole. The stirring needle guide key (8) matches the stirring needle guide keyway. The stirring needle (6) in the shaft hole is connected to the fifth shaft hole through the stirring needle guide key (8) and the stirring needle guide keyway, ensuring that the stirring needle (6) has the freedom to move along the axial center line of the hollow motor rotor shaft (13) in the shoulder (5); the stirring needle retraction shaft (12) in the fourth shaft hole is symmetrically provided with stirring needle retraction shaft guide key (14), and the stirring needle retraction shaft guide keyway is provided at the corresponding position of the stirring needle retraction shaft guide key (14) in the fourth shaft hole. The stirring needle retraction shaft guide key (14) matches the stirring needle retraction shaft guide keyway. The stirring needle retraction shaft (12) in the fourth shaft hole is connected to the fourth shaft hole through the stirring needle retraction shaft guide key (14) and the stirring needle retraction shaft guide keyway, ensuring that the stirring needle retraction shaft (12) has the freedom to move along the axial center line of the hollow motor rotor shaft (13) in the stirring head clamping handle (9); the stirring needle retraction shaft (12) in the sixth shaft hole is clearance-fitted in the sixth shaft hole.

7. The heavy-duty friction stir welding retractable stirring head according to claim 4, characterized in that, An adjusting shim (11) is provided between the stirring head clamping handle (9) and the end face of the hollow motor rotor shaft (13). The stirring head clamping handle (9) and the hollow motor rotor shaft (13) are coaxially fixed by screws passing through the stirring head clamping handle (9), the adjusting shim (11) and the hollow motor rotor shaft (13). The shaft shoulder (5) and the stirring head clamping handle (9) are coaxially fixed by end face screws and side screws.

8. The heavy-duty friction stir welding retractable stirring head according to any one of claims 3-7, characterized in that, The stirring head clamping handle (9) is compatible with conventional stirring heads for heavy-duty friction stir welding. The conventional stirring head for heavy-duty friction stir welding is installed at the front end of the heavy-duty friction stir welding spindle (2) via the stirring head clamping handle (9). The rotation of the stirring head clamping handle (9) is controlled by the heavy-duty friction stir welding spindle (2), which in turn drives the conventional stirring head for heavy-duty friction stir welding to rotate synchronously.

Images