Friction stir welding head, using method thereof and automatic machine tool equipment

Abstract

The invention relates to a friction stir welding head, a using method thereof and automatic machine tool equipment, the welding head comprises an upper shell assembly, a lower shell assembly, an upper rotating shaft assembly, a lower rotating shaft assembly, a stirring needle and a shaft shoulder, the upper shell assembly and the lower shell assembly are oppositely distributed up and down, and the lower shell assembly can move up and down and be positioned; the lower rotating shaft assembly is rotatably inserted into the lower shell assembly, and the shaft shoulder is vertically and fixedly mounted at the lower end of the lower rotating shaft assembly; the upper rotating shaft assembly is rotatably inserted into the upper shell assembly, the upper end of the upper rotating shaft assembly extends out of the upper end of the upper shell assembly, and the lower end of the upper rotating shaft assembly is in transmission connection with the upper end of the lower rotating shaft assembly; the stirring needle is vertically and fixedly installed at the lower end of the upper rotating shaft assembly, and the lower end penetrates through the lower rotating shaft assembly and the shaft shoulder. The device is compact in structure, high in integration level, large in pressure adjusting range, free in switching of constant-pressure constant-displacement double machining modes, novel and unique in rotating axial coupling motion structure, capable of achieving withdrawing of the stirring needle, simple in control principle, high in precision and high in reliability.

Description

Technical Field

[0001] This invention relates to the field of friction stir welding technology, specifically to a friction stir welding head, its application method, and automated machine tool equipment. Background Technology

[0002] Friction stir welding (FSW) is a solid-state joining technology based on friction welding, invented in 1991 by the Welding Institute (FSW) in the UK. Its principle involves a non-wearing shoulder rotating and embedding itself into the weld interface. As the shoulder moves forward along the weld, the plasticized metal forms a dense solid-state bond under mechanical stirring and upsetting. Friction stir welding offers advantages such as stable quality, low cost, and minimal post-weld deformation, making it particularly suitable for welding non-ferrous metals such as aluminum alloys. It has broad application prospects in aerospace, shipbuilding, high-speed train, and automotive manufacturing. Factors affecting the performance of friction stir welds include rotational speed, welding speed, shoulder shape and size, upsetting force, welding materials and thickness, advance angle, and tilt direction.

[0003] The joining mechanism of friction stir welding (FSW) is the result of the interaction between the frictional heat generated by the non-consumable stirring tool and the plastic flow of the metal material. Under the friction and compression of the high-speed rotating stirring tool shoulder and stirring pin, the metals being joined generate strong thermoplastic flow and metallurgical diffusion reactions, ultimately forming a dense weld joint with excellent mechanical properties through the upsetting of the stirring tool shoulder. The realization of the friction stir welding process principle is based on the development of friction stir welding equipment.

[0004] Among them, automated friction stir welding (FSW) machine tools are the foundation for realizing and completing the FSW welding process. According to the requirements of the FSW welding process, the friction welding process requires a completely rigidly fixed sample and a large axial upsetting pressure and lateral movement friction force. Therefore, the design and manufacture of welding heads that can withstand high loads naturally become the key components of FSW welding equipment. Currently, most of the friction stir welding heads seen in the domestic and international markets adopt a single-function mode of displacement or pressure control, and their structures are usually relatively complex, with low processing applicability and flexibility, and high application costs. Summary of the Invention

[0005] This invention addresses the technical problems existing in the prior art by providing a friction stir welding head, its application method, and an automated machine tool.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A friction stir welding head includes: an upper housing assembly, a lower housing assembly, an upper rotating shaft assembly, a lower rotating shaft assembly, a stirring pin, and a shoulder. The upper housing assembly and the lower housing assembly are arranged vertically opposite each other, and the lower housing assembly is located below the upper housing assembly. It can move vertically and be positioned. The lower rotating shaft assembly is rotatably inserted into the lower housing assembly, and the shoulder is vertically fixedly installed at the lower end of the lower rotating shaft assembly, with its lower end extending outside the lower end of the lower housing assembly; the upper rotating shaft assembly is rotatably inserted into the upper housing assembly, with its upper end extending outside the upper end of the upper housing assembly, for connecting to the machine tool, and the lower end of the upper rotating shaft assembly is drively connected to the upper end of the lower rotating shaft assembly; the stirring needle is vertically fixedly installed at the lower end of the upper rotating shaft assembly, with its lower end penetrating through the lower rotating shaft assembly and the shoulder.

[0007] The beneficial effects of the present invention are as follows: During the operation, firstly, the lower housing assembly is moved downward to a set position in a manner that can be conceived by those skilled in the art; then, the upper rotating shaft assembly is driven to rotate by the machine tool, and the upper rotating shaft assembly drives the stirring needle to rotate; at the same time, the upper rotating shaft assembly drives the lower rotating shaft assembly to rotate, and the lower rotating shaft assembly drives the shoulder and the stirring needle to rotate, thereby completing the welding operation, which is convenient for welding.

[0008] This invention features a compact structure, high integration, a wide pressure adjustment range, free switching between constant pressure and constant displacement processing modes, a novel and unique rotary-axial coupling motion structure that enables the stirring needle to retract, and a simple, highly precise, and reliable control principle.

[0009] Based on the above technical solution, the present invention can be further improved as follows.

[0010] Furthermore, the upper housing assembly includes an upper housing, and the lower housing assembly includes a lower housing. The upper housing and the lower housing are distributed vertically opposite each other, and the lower housing is located below the upper housing. It can move vertically and be positioned. The upper rotating shaft assembly is mounted on the upper housing, and the lower rotating shaft assembly is mounted on the lower housing.

[0011] The advantages of adopting the above-mentioned further solution are that the structure is simple and the design is reasonable. The upper rotating shaft assembly uses the upper shell as the mounting base, while the lower rotating shaft assembly uses the lower shell as the mounting base, making assembly convenient.

[0012] Furthermore, the upper rotating shaft assembly includes a centering cone shank and an upper gear shaft. The centering cone shank is vertically mounted on the upper housing for connecting to the machine tool. The upper gear shaft is vertically arranged, with its upper end fixedly connected to the lower end of the centering cone shank. The upper end of the stirring needle is connected to the lower end of the upper gear shaft.

[0013] The beneficial effect of adopting the above-mentioned further solution is that during the operation, the machine tool drives the centering cone shank to rotate, the centering cone shank drives the upper gear shaft to rotate, and the upper gear shaft drives the stirring needle to rotate, thereby realizing the rapid transmission of power so as to complete the welding operation and making the operation convenient.

[0014] Furthermore, the upper end of the stirring needle is connected to the lower end of the upper gear shaft by a vertically arranged mandrel.

[0015] The beneficial effect of adopting the above-mentioned further solution is that during the operation, the machine tool drives the centering cone shank to rotate, the centering cone shank drives the upper gear shaft to rotate, and the upper gear shaft drives the stirring needle to rotate through the mandrel, thereby realizing the rapid transmission of power so as to complete the welding operation and making the operation convenient.

[0016] Furthermore, the lower rotating shaft assembly includes a lower gear shaft and a tapered shank connector. The lower gear shaft is vertically rotatably mounted on the lower housing, and its upper end is connected to the lower end of the upper gear shaft for transmission. The tapered shank connector is vertically arranged, and its upper end is fixedly connected to the lower end of the lower gear shaft. The upper end of the shaft shoulder is fixedly connected to the lower end of the tapered shank connector.

[0017] The beneficial effect of adopting the above-mentioned further solution is that during the operation, the machine tool drives the centering cone shank to rotate, the centering cone shank drives the upper gear shaft to rotate, and the upper gear shaft drives the stirring needle to rotate. At the same time, the upper gear shaft drives the lower gear shaft to rotate, the lower gear shaft drives the tapered shank connector to rotate, and the tapered shank connector drives the shaft shoulder to rotate, realizing the rapid transmission of power and completing the welding operation at the same time, making the operation convenient.

[0018] Furthermore, a gear is coaxially fixedly sleeved on the lower end of the upper gear shaft, and a channel is provided inside the lower gear shaft for the upper gear shaft and the stirring needle to pass through; a gear ring is coaxially fixedly installed in the upper end of the channel, the gear ring meshes with the gear, and can slide along the axial direction of the gear.

[0019] The advantages of adopting the above-mentioned further solution are that the structure is simple and the design is reasonable. During the rotation of the upper gear shaft, the power is transmitted by the meshing between the gear coaxially fixed at its lower end and the gear ring in the channel of the lower gear shaft, so that the power is transmitted from the upper rotating component to the lower rotating component, and the power transmission is convenient. In addition, the lower gear shaft can utilize the axial sliding fit between the gear ring and the gear to ensure the vertical movement of the lower housing assembly and avoid mutual interference.

[0020] Furthermore, the lower housing is connected to the upper housing via a linkage mechanism, and a driving component is mounted on the upper housing, with the driving end of the driving component connected to the lower housing.

[0021] The advantages of adopting the above-mentioned further solution are that the structure is simple and the design is reasonable. The lower shell is connected to the upper shell through a linkage mechanism, which can realize the connection between the upper and lower shells, achieve high integration, and ensure that the vertical movement of the lower shell is not affected.

[0022] Furthermore, the linkage mechanism includes multiple linkage assemblies, which are evenly spaced between the upper housing and the lower housing; the driving component includes multiple hydraulic cylinders, which are evenly spaced and fixedly installed on the upper housing, with their extension and retraction ends pointing vertically downward and respectively fixedly connected to the lower housing.

[0023] The advantage of adopting the above-mentioned further solution is that during operation, the lower housing can be moved up and down synchronously by using multiple hydraulic cylinders, which makes adjustment convenient. In addition, the lower housing is connected to the upper housing through multiple linkage assemblies, which can achieve the connection between the upper and lower housings with high integration, and also ensure that the vertical movement of the lower housing is not affected.

[0024] The present invention also relates to a method of using the friction stir welding head as described above, comprising the following specific steps: The lower housing assembly is moved downward to the set position, then the upper rotating shaft assembly rotates and the stirring needle rotates, which in turn drives the lower rotating shaft assembly to rotate. The lower rotating shaft assembly drives the shoulder to rotate, and then the machine tool Z-axis drives the entire welding head to move linearly so that the stirring needle penetrates the workpiece to be welded and the shoulder contacts the surface of the workpiece to be welded, so as to perform welding operations in a constant pressure or constant displacement mode. When the welding operation reaches the weld termination position, the stirring pin and the shoulder continue to rotate, and the stirring pin retracts to eliminate the weld keyhole.

[0025] The beneficial effect of adopting the above-mentioned further solution is that the present invention also provides a method for using the friction stir welding head as described above. The method is simple, has a large pressure adjustment range, allows free switching between constant pressure and constant displacement dual processing modes, and features a novel and unique rotational axial coupling motion structure that can realize the retraction of the stirring needle. The control principle is simple, highly accurate, and highly reliable.

[0026] The present invention also relates to an automated machine tool device, including the friction stir welding head as described above.

[0027] The beneficial effect of adopting the above-mentioned further solutions is that the present invention also provides an automated machine tool, which has a compact structure, high integration, large pressure adjustment range, free switching between constant pressure and constant displacement dual processing modes, a novel and unique rotary axial coupling motion structure, can realize the retraction of the stirring needle, and has a simple control principle, high precision, and strong reliability. Attached Figure Description

[0028] Figure 1This is a front sectional view of the welding head in the axial zero position in this invention; Figure 2 This is a front sectional view of the welding head at its maximum axial stroke in this invention; Figure 3 In order to be in Figure 1 A cross-sectional view of the linkage mechanism from the center upwards. Figure 4 In order to be in Figure 1 A cross-sectional view taken from the center of the linkage mechanism downwards. Figure 5 In order to be in Figure 3 A sectional view taken at an angle through the center of the diagonal hydraulic cylinder and displacement sensor; Figure 6 for Figure 3 A cross-sectional view at the point of maximum axial travel; Figure 7 This is a schematic diagram of the hydraulic system in this invention.

[0029] The attached diagram lists the components represented by each number as follows: 1. Centering cone shank; 2. Stop locating ring; 3. Upper housing; 4. Upper bearing assembly; 5. Upper bushing; 6. Connecting rod assembly; 7. Upper housing outer end cover; 8. Lower housing outer end cover; 9. Lower bearing assembly; 10. Lower housing; 11. Lower bushing; 12. Welding head end cover; 13. Transition connecting block; 14. Cone shank connector; 15. Shoulder; 16. Compression spring; 17. Upper gear shaft; 18. Sliding key; 19. Upper housing inner end cover; 20. Lower housing inner end cover; 21. Lower gear shaft; 22. Mandrel; 23. Stirring needle; 24. Hydraulic cylinder; 25. Displacement sensor; 26. High-frequency response valve assembly; 27. Pressure sensor. Detailed Implementation

[0030] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0032] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this technology based on the specific circumstances.

[0033] In the description of this application, spatial relation terms such as "below," "under," "below," "below," "above," "over," etc., are used herein to describe the relationship between one element or feature shown in the figures and other elements or features. It should be understood that, in addition to the orientation shown in the figures, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figures is flipped, an element or feature described as "below" or "under" or "below" of other elements or features will be oriented "above" other elements or features. Therefore, the exemplary terms "below" and "under" can include both upper and lower orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein are interpreted accordingly.

[0034] In the description of this application, the term "for example" is used to mean "used as an example, illustration, or description." Any embodiment described as "for example" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use the invention. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that the invention can be made without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid obscuring the description of the invention with unnecessary detail. Therefore, the invention is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0035] Example 1 like Figures 1 to 7 As shown, this embodiment provides a friction stir welding head, including: an upper housing assembly, a lower housing assembly, an upper rotating shaft assembly, a lower rotating shaft assembly, a stirring pin 23 and a shoulder 15. The upper housing assembly and the lower housing assembly are distributed vertically opposite each other, and the lower housing assembly is located below the upper housing assembly. It can move vertically and be positioned. The lower rotating shaft assembly is rotatably inserted into the lower housing assembly, and the shoulder 15 is vertically fixedly installed at the lower end of the lower rotating shaft assembly, with its lower end extending outside the lower end of the lower housing assembly; the upper rotating shaft assembly is rotatably inserted into the upper housing assembly, with its upper end extending outside the upper end of the upper housing assembly, for connecting the machine tool, and the lower end of the upper rotating shaft assembly is drively connected to the upper end of the lower rotating shaft assembly; the stirring needle 23 is vertically fixedly installed at the lower end of the upper rotating shaft assembly via a connecting rod, and its lower end passes through the lower rotating shaft assembly and the shoulder 15.

[0036] During the operation, firstly, the lower housing assembly is moved downward to the set position in a manner that can be conceived by those skilled in the art; then, the upper rotating shaft assembly is driven to rotate by the machine tool, and the upper rotating shaft assembly drives the stirring needle 23 to rotate; at the same time, the upper rotating shaft assembly drives the lower rotating shaft assembly to rotate, and the lower rotating shaft assembly drives the shoulder 15 and the stirring needle 23 to rotate, thereby completing the welding operation, which is convenient for welding.

[0037] Preferably, in this embodiment, the stirring needle 23 has a needle-like structure.

[0038] In addition, in this embodiment, the relative rotation of the stirring needle 23, the shoulder 15 and the tool handle is restricted circumferentially by the set screw pin in order to transmit torque.

[0039] Preferably, in this embodiment, the shoulder 15 has a cylindrical structure, and the stirring needle 23 is inserted into the shoulder 15 and can move up and down.

[0040] This embodiment features a compact structure, high integration, a wide pressure adjustment range, free switching between constant pressure and constant displacement processing modes, a novel and unique rotary-axial coupling motion structure that enables the stirring needle to retract, and a simple, highly precise, and reliable control principle.

[0041] Example 2 Based on Embodiment 1, in this embodiment, the upper housing assembly includes an upper housing 3, and the lower housing assembly includes a lower housing 10. The upper housing 3 and the lower housing 10 are distributed vertically opposite each other, and the lower housing 10 is located below the upper housing 3 and can move vertically and be positioned. The upper rotating shaft assembly is mounted on the upper housing 3, and the lower rotating shaft assembly is mounted on the lower housing 10.

[0042] The scheme has a simple structure and reasonable design. The upper rotating shaft assembly uses the upper shell 3 as the mounting base, while the lower rotating shaft assembly uses the lower shell 10 as the mounting base, making assembly convenient.

[0043] Preferably, in this embodiment, the upper shell 3 is preferably a cylindrical shell.

[0044] In addition, the upper shell 3 is preferably a structure that is thicker at the top and thinner at the bottom.

[0045] Preferably, in this embodiment, the lower housing 10 is preferably a cylindrical housing.

[0046] In addition, the lower shell 10 is preferably thicker in the middle and thinner at both ends.

[0047] Furthermore, the upper housing 3 and the lower housing 10 are respectively provided with vertically penetrating installation channels.

[0048] Example 3 Based on Embodiment 2, in this embodiment, the upper rotating shaft assembly includes a centering cone shank 1 and an upper gear shaft 17. The centering cone shank 1 is vertically mounted on the upper housing 3 for connecting to the machine tool. The upper gear shaft 17 is vertically arranged, and its upper end is fixedly connected to the lower end of the centering cone shank 1. The upper end of the stirring needle 23 is connected to the lower end of the upper gear shaft 17.

[0049] During operation, the machine tool drives the centering cone shank 1 to rotate, the centering cone shank 1 drives the upper gear shaft 17 to rotate, and the upper gear shaft 17 drives the stirring needle 23 to rotate, thereby realizing the rapid transmission of power to complete the welding operation and making the operation convenient.

[0050] Preferably, in this embodiment, the upper end of the centering cone handle 1 has a cone-shaped structure, and its lower end has a cylindrical structure.

[0051] Preferably, in this embodiment, the upper gear shaft 17 is preferably a cylindrical structure that is thicker at the upper end and thinner at the lower end.

[0052] In addition, the upper end of the aforementioned upper gear shaft 17 extends to a shoulder, which rests on a step on the upper housing 3.

[0053] Furthermore, the upper gear shaft 17 is fitted with an upper bushing 5, which is rotatably connected to the upper housing 3 via an upper bearing assembly 4.

[0054] Preferably, in this embodiment, the upper end of the upper gear shaft 17 is provided with a mounting groove, the lower end of the centering cone shank 1 extends into the mounting groove, and is connected to the upper end of the upper gear shaft 17 through the sliding key 18 to achieve synchronous rotation of the two.

[0055] Preferably, in this embodiment, the lower end of the centering cone shank 1 is provided with a groove, and a compression spring 16 is installed in the groove. The upper and lower ends of the compression spring 16 abut against the bottom of the groove and the bottom of the mounting groove, respectively. This design is relatively reasonable. The compression spring 16 makes a flexible contact between the lower end of the centering cone shank 1 and the upper end of the upper gear shaft 17, preventing over-positioning.

[0056] Furthermore, once the upper housing 3 is tightened and positioned, the compression spring 16 generates a certain preload to prevent hard contact collision between the two end faces.

[0057] Preferably, in this embodiment, the upper end of the upper housing 3 is provided with a stop positioning ring 2 and a T-shaped groove, which form a coaxial positioning and tensioning connection with the external welding machine tool equipment. The lower end of the upper housing 3 is provided with an upper housing outer end cover 7, which presses and seals the lower end bearing of the upper bearing assembly 4.

[0058] In addition, the upper T-shaped groove of the upper housing 3 is fixed to the machine tool spindle by the tension screw, so that there is no relative movement, and it can prevent the centering cone shank 1 from axially dislodging. The centering cone shank 1 is installed in the mounting hole of the machine tool spindle tool holder for positioning, tensioning and transmitting rotational motion and torque.

[0059] Preferably, in this embodiment, an inner end cover 19 of the upper housing is installed at the lower end of the upper gear shaft 17. The upper gear shaft 17 and the inner end cover 19 of the upper housing are used to press and seal the upper bearing assembly 4.

[0060] Example 4 Based on Example 3, in this example, the upper end of the stirring needle 23 is connected to the lower end of the upper gear shaft 17 by a vertically arranged spindle 22.

[0061] During operation, the machine tool drives the centering cone shank 1 to rotate, which in turn drives the upper gear shaft 17 to rotate. The upper gear shaft 17 then drives the stirring needle 23 to rotate via the spindle 22, thus achieving rapid power transmission to complete the welding operation and making the operation convenient.

[0062] Preferably, in this embodiment, the mandrel 22 is preferably a cylindrical rod structure, with its upper end fixedly connected to the lower end of the upper gear shaft 17, and the lower end of the mandrel 22 fixedly connected to the upper end of the stirring needle 23.

[0063] Example 5 Based on any one of Embodiments 3 to 4, in this embodiment, the lower rotating shaft assembly includes a lower gear shaft 21 and a tapered shank connector 14. The lower gear shaft 21 is vertically rotatably mounted on the lower housing 10, and its upper end is connected to the lower end of the upper gear shaft 17 for transmission. The tapered shank connector 14 is vertically arranged, and its upper end is fixedly connected to the lower end of the lower gear shaft 21. The upper end of the shoulder 15 is fixedly connected to the lower end of the tapered shank connector 14.

[0064] During operation, the machine tool drives the centering cone shank 1 to rotate, the centering cone shank 1 drives the upper gear shaft 17 to rotate, and the upper gear shaft 17 drives the stirring needle 23 to rotate. At the same time, the upper gear shaft 17 drives the lower gear shaft 21 to rotate, the lower gear shaft 21 drives the tapered shank connector 14 to rotate, and the tapered shank connector 14 drives the shaft shoulder 15 to rotate, realizing the rapid transmission of power and completing the welding operation at the same time, making the operation convenient.

[0065] Preferably, in this embodiment, the lower gear shaft 21 is preferably cylindrical.

[0066] In addition, a lower bushing 11 is fitted on the lower gear shaft 21, and the lower bushing 11 is rotatably connected to the lower housing 10 through the lower bearing assembly 9.

[0067] Preferably, in this embodiment, the lower housing 10 is provided with an outer end cover 8 at the upper end to press and seal the upper bearing of the lower bearing assembly 9, and the lower housing 10 is provided with a welding head end cover 12 at the lower end, and the welding head end cover 12 is provided with a groove for installing the sealing component.

[0068] In addition, an inner end cover 20 is installed inside the upper end of the lower housing 10, and the inner end cover 20 is located in the through hole at the center of the outer end cover 8 of the lower housing. The lower gear shaft 21 and the inner end cover 20 are used to press and seal the lower bearing assembly 9.

[0069] Preferably, in this embodiment, the upper end of the tapered shank connector 14 is tapered, and its lower end is cylindrical.

[0070] In addition, the aforementioned cone-handle connector 14 is provided with a channel that runs vertically through it, and the spindle 22 and stirring needle 23 are distributed vertically within the channel.

[0071] Preferably, in this embodiment, the tapered shank connector 14 is positioned and connected to the inner tapered hole at the lower end of the lower gear shaft 21 via the transition connecting block 13, and the shoulder 15 is connected to the bottom of the lower gear shaft 21 via the upper cylindrical surface and the stepped surface.

[0072] Preferably, in this embodiment, a motion limiting component, such as a limiting pin, is provided between the stirring needle 23 and the shoulder 15, and between the shoulder 15 and the lower housing 10. The limiting pin is used to limit the axial displacement stroke of the shoulder 15 and the stirring needle 23, and to prevent relative rotation between the shoulder 15, the stirring needle 23 and the tapered shank connector 14.

[0073] Example 6 Based on Embodiment 5, in this embodiment, a gear is coaxially fixedly sleeved on the lower end of the upper gear shaft 17, and a channel is provided in the lower gear shaft 21 for the upper gear shaft 17 and the stirring needle 23 to pass through; a gear ring is coaxially fixedly installed in the upper end of the channel, the gear ring meshes with the gear, and can slide along the axial direction of the gear.

[0074] The scheme has a simple structure and reasonable design. During the rotation of the upper gear shaft 17, the power is transmitted by the meshing between the gear fixedly sleeved on its lower end and the gear ring in the channel of the lower gear shaft 21, so that the power is transmitted from the upper rotating component to the lower rotating component, and the power transmission is convenient. In addition, the lower gear shaft 21 can utilize the axial sliding fit between the gear ring and the gear to ensure the vertical movement of the lower housing assembly and avoid mutual interference.

[0075] Example 7 Based on any one of Embodiments 2 to 6, in this embodiment, the lower housing 10 is connected to the upper housing 3 via a linkage mechanism, a driving member is installed on the upper housing 3, and the driving end of the driving member is connected to the lower housing 10.

[0076] The solution has a simple structure and reasonable design. The lower housing 10 is connected to the upper housing 3 through a linkage mechanism, which can realize the connection between the upper housing 3 and the lower housing 10, with high integration, and also ensure that the vertical movement of the lower housing 10 is not affected.

[0077] Based on the above scheme, the linkage mechanism plays a guiding, constraining, and stiffness-enhancing role in the axial displacement movement of the entire welded joint.

[0078] Example 8 Based on Embodiment 7, in this embodiment, the linkage mechanism includes multiple linkage assemblies 6, which are evenly spaced between the upper housing 3 and the lower housing 10; the driving component includes multiple hydraulic cylinders 24, which are evenly spaced and fixedly installed on the upper housing 3, with their extension and retraction ends pointing vertically downward and fixedly connected to the lower housing 10 respectively.

[0079] During operation, multiple hydraulic cylinders 24 are used to extend and retract synchronously to move the lower housing 10 up and down, which is convenient for adjustment; In addition, the lower housing 10 is connected to the upper housing through multiple connecting rod assemblies 6, which can realize the connection between the upper housing 3 and the lower housing 10 with high integration, and also ensure that the vertical movement of the lower housing 10 is not affected.

[0080] Preferably, in this embodiment, the number of the above-mentioned connecting rod assemblies 6 is preferably four, and the four connecting rod assemblies 6 are evenly distributed between the upper housing 3 and the lower housing 10.

[0081] Preferably, in this embodiment, each of the above-mentioned linkage assemblies 6 includes an upper linkage and a lower linkage. One end of the upper linkage is rotatably connected to the upper housing 3, one end of the lower linkage is rotatably connected to the other end of the upper linkage, and the other end is rotatably connected to the lower housing 10.

[0082] Preferably, in this embodiment, the number of the above-mentioned hydraulic cylinders 24 is preferably four, and the four hydraulic cylinders 24 are evenly spaced and fixedly installed on the upper housing 3.

[0083] Preferably, in this embodiment, a displacement sensor 25 is provided between the upper housing 3 and the lower housing 10, and the wiring of the plurality of hydraulic cylinders 24 and the displacement sensor 25 is connected to the hydraulic control system.

[0084] In addition, the displacement sensor 25 is used to measure and feedback the axial displacement between the upper housing part (i.e. the fixed part of the welding head) and the lower housing part (i.e. the movable part of the welding head). It can accurately collect the relative position between the two and feed back the data in a timely manner, which helps to accurately control the relative welding position and welding pressure of the shoulder 15 and the stirring needle 23, so as to ensure the safety of the welding process.

[0085] Based on the above scheme, the upper housing 3 is fixed to the Z-axis of the machine tool, and at the same time, the upper chambers of the four hydraulic cylinders 24 between the upper housing 3 and the lower housing 10 are filled with oil to ensure that the lower housing 10 has no relative displacement with respect to the workpiece in the vertical direction.

[0086] Example 9 Based on the above embodiments, this embodiment also provides a method for using the friction stir welding head as described above, including the following specific steps: The lower housing 10 assembly is moved downward to the set position. Then the upper rotating shaft assembly rotates the stirring needle 23, which in turn drives the lower rotating shaft assembly to rotate. The lower rotating shaft assembly drives the shoulder 15 to rotate. Then the machine tool Z axis drives the entire welding head to move linearly so that the stirring needle 23 penetrates the workpiece to be welded and the shoulder 15 contacts the surface of the workpiece to be welded, so as to perform welding operations in a constant pressure or constant displacement mode. When the welding operation reaches the weld termination position, the stirring pin 23 and the shoulder 15 continue to rotate, and the stirring pin 23 retracts to eliminate the weld keyhole.

[0087] Based on the above scheme, the retraction of the stirring needle is the upward movement of the machine tool's Z-axis.

[0088] The method for using friction stir welding heads includes the following specific steps: (1) Constant displacement machining mode. Through the hydraulic control system, combined with the position feedback of the displacement sensor 25, the hydraulic cylinder 24 is kept at zero position. Its special mechanical locking structure is used to connect the fixed part and the moving part of the welding head into a static body in the axial direction. The shoulder 15 and the stirring needle 23 are adjusted to the working state. The constant displacement welding machining mode is realized by controlling the relative static position relationship between the machine tool spindle and the welded part.

[0089] (2) Constant pressure processing mode. Through the hydraulic control system, the upper chamber of the hydraulic cylinder 24 is filled with oil to disengage the piston and piston rod from the zero-position mechanical locking state. Then, the integrated piston rod moves downward, pushing the shoulder 15 of the welding head to the welding position and setting the upsetting pressure. The constant pressure welding processing mode with axial displacement adaptive adjustment function is realized through the high-frequency response valve group 26 and pressure sensor 27 in the hydraulic system. The concept of "constant pressure with axial displacement adaptive adjustment function" is reflected in the fact that during the welding process, when the upsetting force between the welding head and the welded part changes, the pressure sensor 27 of the hydraulic control system can drive the hydraulic cylinder 24 to adjust the axial displacement of the welding head according to the actual working pressure feedback to maintain the constant upsetting force.

[0090] (3) Retraction of stirring pin 23. During the welding process, according to the actual processing needs, while the shoulder 15 and the welded part are still in the state of being pressed and working normally, the retraction function of stirring pin 23 in the welding position is realized by the relative movement between the lower housing assembly of the welding head and the machine tool spindle; the relative movement between the lower housing assembly of the welding head and the machine tool spindle: that is, the machine tool spindle moves away from the welded part at a certain speed, while the moving part of the welding head extends through the piston rods of the four hydraulic cylinders 24 to keep the shoulder in contact with the welded part and the upsetting force, that is, the shoulder 15 of the moving part of the welding head and the welded part are relatively stationary.

[0091] This embodiment also provides a method for using the friction stir welding head as described above. The method is simple, has a wide pressure adjustment range, allows free switching between constant pressure and constant displacement dual processing modes, and features a novel and unique rotary-axial coupling motion structure that enables the stirring needle to retract. The control principle is simple, highly precise, and highly reliable.

[0092] Example 10 Based on Example 9, this example also provides an automated machine tool, including the friction stir welding head as described above.

[0093] This embodiment also provides an automated machine tool, which has a compact structure, high integration, wide pressure adjustment range, free switching between constant pressure and constant displacement dual processing modes, a novel and unique rotary-axial coupling motion structure, can realize the retraction of the stirring needle, and has a simple control principle, high precision, and strong reliability.

[0094] This invention provides a friction stir welding head, its application method, and an automated machine tool. The actual operation process is as follows: (1) Constant displacement machining mode. Through the hydraulic control system, combined with the position feedback of the displacement sensor 25, the hydraulic cylinder 24 is kept at zero position. Its special mechanical locking structure is used to connect the fixed part and the moving part of the welding head into a static body in the axial direction. The shoulder 15 and the stirring needle 23 are adjusted to the working state. The constant displacement welding machining mode is realized by controlling the relative static position relationship between the machine tool spindle and the welded part.

[0095] (2) Constant pressure processing mode. Through the hydraulic control system, the upper chamber of the hydraulic cylinder 24 is filled with oil to disengage the piston and piston rod from the zero-position mechanical locking state. Then, the integrated piston rod moves downward, pushing the shoulder 15 of the welding head to the welding position and setting the upsetting pressure. The constant pressure welding processing mode with axial displacement adaptive adjustment function is realized through the high-frequency response valve group 26 and pressure sensor 27 in the hydraulic system. The concept of "constant pressure with axial displacement adaptive adjustment function" is reflected in the fact that during the welding process, when the upsetting force between the welding head and the welded part changes, the pressure sensor 27 of the hydraulic control system can drive the hydraulic cylinder 24 to adjust the axial displacement of the welding head according to the actual working pressure feedback to maintain the constant upsetting force.

[0096] (3) Retraction of stirring pin 23. During the welding process, according to the actual processing needs, while the shoulder 15 and the welded part are still in the state of being pressed and working normally, the retraction function of stirring pin 23 in the welding position is realized by the relative movement between the lower housing assembly of the welding head and the machine tool spindle; the relative movement between the lower housing assembly of the welding head and the machine tool spindle: that is, the machine tool spindle moves away from the welded part at a certain speed, while the moving part of the welding head extends through the piston rods of the four hydraulic cylinders 24 to keep the shoulder in contact with the welded part and the upsetting force, that is, the shoulder 15 of the moving part of the welding head and the welded part are relatively stationary.

[0097] The welding head proposed in this invention is a modular design adapted to FSW automated machine tool equipment. It is connected to the machine tool spindle to transmit high-speed rotary motion and uses a hydraulic cylinder 24 and a linkage mechanism for axial displacement drive. By controlling the action and position locking of the hydraulic cylinder 24, it can achieve free switching between constant pressure and constant displacement dual processing modes, rotary axial coupling motion, and retraction of the stirring needle 23. It has the characteristics of compact structure, high integration, large pressure adjustment range, novel and unique structure, and simple, accurate and reliable control principle.

[0098] Compared with existing friction stir welding joints, the present invention has the following advantages: (1) The rotating axial coupling motion structure of the welding head is simple and unique. It can move up and down along the axis while rotating at high speed. It innovatively adopts internal and external gear meshing and sliding design to realize the rotational motion transmission of the central rotating shaft assembly of the fixed part and the moving part of the welding head. It uses hydraulic cylinder in conjunction with linkage mechanism to realize the axial displacement motion between the fixed part and the moving part.

[0099] (2) The welding head has a compact structure and high integration, and has the functions of constant pressure and constant displacement dual processing modes. The equipment processing adaptability and flexibility are significantly improved. The retraction function of the stirring needle in the welding position can be realized through the relative static movement between the welding head and the machine tool spindle. When the hydraulic cylinder is in the zero position, the special mechanical locking structure makes the fixed part and the moving part axially connected as a static body. By controlling the relative position relationship between the machine tool spindle and the welded part, the constant displacement non-tilt angle welding processing mode is realized. The hydraulic system drives the hydraulic cylinder to move downward to get out of the zero position locking state. When it reaches the welding position, the preset working pressure is used. The constant pressure non-tilt angle welding processing mode with axial displacement adaptive adjustment function is realized through the movement path of the machine tool spindle.

[0100] (3) The overall structure of the welding head is simple, reliable and novel. It has a wide range of axial pressure control and high precision. There are no parts that are difficult to manufacture or obtain. While ensuring the stability of the equipment, it can significantly reduce the manufacturing cost of the equipment.

[0101] While embodiments or examples of this disclosure have been described with reference to the accompanying drawings, it should be understood that the above embodiments are merely exemplary embodiments or examples, and the scope of the invention is not limited by these embodiments or examples, but only by the granted claims and their equivalents. Various elements in the embodiments or examples may be omitted or replaced by their equivalents. Furthermore, the steps may be performed in a different order than that described in this disclosure. Further, various elements in the embodiments or examples may be combined in various ways. Importantly, as the technology evolves, many elements described herein can be replaced by equivalents that appear after this disclosure.

Claims

1. A friction stir welding head, characterized in that, include: The upper housing assembly, the lower housing assembly, the upper rotating shaft assembly, the lower rotating shaft assembly, the stirring needle (23) and the shoulder (15) are arranged vertically opposite to each other, and the lower housing assembly is located below the upper housing assembly. It can move up and down and be positioned. The lower rotating shaft assembly is rotatably inserted into the lower housing assembly, and the shoulder (15) is vertically fixedly installed at the lower end of the lower rotating shaft assembly, with its lower end extending to the outside of the lower end of the lower housing assembly; the upper rotating shaft assembly is rotatably inserted into the upper housing assembly, with its upper end extending to the outside of the upper end of the upper housing assembly, for connecting the machine tool, and the lower end of the upper rotating shaft assembly is drively connected to the upper end of the lower rotating shaft assembly; the stirring needle (23) is vertically fixedly installed at the lower end of the upper rotating shaft assembly, with its lower end penetrating the lower rotating shaft assembly and the shoulder (15).

2. The friction stir welding head according to claim 1, characterized in that, The upper housing assembly includes an upper housing (3), and the lower housing assembly includes a lower housing (10). The upper housing (3) and the lower housing (10) are distributed vertically opposite each other, and the lower housing (10) is located below the upper housing (3). It can move vertically and be positioned. The upper rotating shaft assembly is installed on the upper housing (3), and the lower rotating shaft assembly is installed on the lower housing (10).

3. The friction stir welding head according to claim 2, characterized in that, The upper rotating shaft assembly includes a centering cone shank (1) and an upper gear shaft (17). The centering cone shank (1) is vertically rotated and vertically mounted on the upper housing (3) for connecting to the machine tool. The upper gear shaft (17) is vertically arranged, and its upper end is fixedly connected to the lower end of the centering cone shank (1). The upper end of the stirring needle (23) is connected to the lower end of the upper gear shaft (17).

4. The friction stir welding head according to claim 3, characterized in that, The upper end of the stirring needle (23) is connected to the lower end of the upper gear shaft (17) by a vertically arranged mandrel (22).

5. The friction stir welding head according to claim 3, characterized in that, The lower rotating shaft assembly includes a lower gear shaft (21) and a tapered shank connector (14). The lower gear shaft (21) is vertically rotatably mounted on the lower housing (10), and its upper end is connected to the lower end of the upper gear shaft (17) for transmission. The tapered shank connector (14) is vertically arranged, and its upper end is fixedly connected to the lower end of the lower gear shaft (21). The upper end of the shoulder (15) is fixedly connected to the lower end of the tapered shank connector (14).

6. The friction stir welding head according to claim 5, characterized in that, The lower end of the upper gear shaft (17) is coaxially fixedly fitted with a gear, and the lower gear shaft (21) is provided with a channel for the upper gear shaft (17) and the stirring needle (23) to pass through; a gear ring is coaxially fixedly installed in the upper end of the channel, the gear ring meshes with the gear and can slide along the axial direction of the gear.

7. The friction stir welding head according to any one of claims 2-6, characterized in that, The lower housing (10) is connected to the upper housing (3) via a linkage mechanism. A driving component is installed on the upper housing (3), and the driving end of the driving component is connected to the lower housing (10).

8. The friction stir welding head according to claim 7, characterized in that, The linkage mechanism includes multiple linkage assemblies (6), which are evenly spaced between the upper housing (3) and the lower housing (10); the driving component includes multiple hydraulic cylinders (24), which are evenly spaced and fixedly installed on the upper housing (3), with their extension and retraction ends pointing vertically downward and fixedly connected to the lower housing (10).

9. A method of using the friction stir welding joint as described in any one of claims 1-8, characterized in that, The specific steps include the following: Move the lower housing (10) assembly downward to the set position, then rotate the upper rotating shaft assembly to rotate the stirring needle (23), and drive the lower rotating shaft assembly to rotate. The lower rotating shaft assembly drives the shoulder (15) to rotate. Then the machine tool Z axis drives the entire welding head to move linearly so that the stirring needle (23) penetrates the workpiece to be welded and the shoulder (15) contacts the surface of the workpiece to be welded, and the welding operation is carried out in constant pressure or constant displacement mode. When the welding operation reaches the weld termination position, the stirring needle (23) and the shoulder (15) continue to rotate, and the stirring needle (23) retracts to eliminate the weld keyhole.

10. An automated machine tool, characterized in that, Includes the friction stir welding head as described in any one of claims 1-8.

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