Friction stir welding stirring head and friction stir welding equipment

Abstract

The invention provides a friction stir welding stirring head and friction stir welding equipment. The friction stir welding stirring head comprises a stirring needle; one end of the stirring needle is connected with the first end of the middle shaft, a plurality of annular grooves are formed in the connecting position of the shaft shoulder end face of the first end and the stirring needle, the annular grooves are formed in the radial direction of the shaft shoulder end face at intervals, every two adjacent annular grooves in the annular grooves are communicated through a groove, and a plurality of cutting edges are arranged on the shaft shoulder end face. The multiple cutting blades are arranged along an involute track with the stirring needle as the center, the outer tangent planes of every two adjacent cutting blades in the multiple cutting blades form a chip removal groove, one end of each chip removal groove communicates with the annular groove, close to the outer edge of the end face of the shaft shoulder, in the multiple annular grooves, and smooth flowing and efficient chip removal of materials in the welding process are achieved; and sufficient mixing of materials in a welding seam area is promoted, uniform friction heat generation between the end face of the shaft shoulder and a workpiece is guaranteed, and the service life of the stirring head is prolonged.

Description

Technical Field

[0001] This invention relates to the field of electric drive technology, and more specifically, to a friction stir welding head and friction stir welding equipment. Background Technology

[0002] In friction stir welding, the shoulder end face of the stirring head is a key part for generating frictional heat, driving the plastic flow of material, and ensuring weld formation. Existing friction stir welding heads often use smooth planes, simple annular grooves, or randomly arranged cutting structures for their shoulder end faces. During welding, the high-temperature plastic material generated by the contact between the shoulder end face and the workpiece lacks an effective flow guidance channel, which easily leads to material accumulation and uneven flow rate at the contact interface. This results in the material not being able to fully fill the weld area along the preset path. At the same time, metal chips, oxide scale, and some incompletely plasticized hard particles generated during welding are difficult to remove quickly from the welding area due to the narrow channels, lack of interconnection between chip removal units, or mismatch in material flow direction of existing chip removal structures, resulting in severe chip removal congestion.

[0003] Furthermore, smooth end faces or unreasonable groove layouts result in uneven distribution of contact friction area between the shoulder end face and the workpiece, leading to significant differences in frictional heat generation efficiency. This causes localized excessively high temperatures in the weld area, resulting in coarse grains, while localized excessively low temperatures lead to insufficient material plasticity. In addition, the lack of scientific arrangement of the cutting edge trajectory makes it impossible to achieve efficient cutting and crushing of the material. Moreover, the lack of smooth connection between the cutting area and the chip removal channel further exacerbates the problems of material flow obstruction and chip removal difficulties.

[0004] There is currently no effective solution to the above problems. Summary of the Invention

[0005] The main objective of this invention is to provide a stirring head and a friction stir welding device to solve the problem of low chip removal efficiency of existing friction stir welding heads in the prior art.

[0006] To achieve the above objectives, according to one aspect of the present invention, a friction stir welding head is provided, comprising: a stirring pin; an intermediate shaft, one end of the stirring pin being connected to a first end of the intermediate shaft, a plurality of annular grooves being provided at the connection between the shoulder end face of the first end and the stirring pin, the plurality of annular grooves being radially spaced along the shoulder end face, two adjacent annular grooves being connected by a groove, a plurality of cutting edges being provided on the shoulder end face, the plurality of cutting edges being arranged around the stirring pin as the center and along an involute trajectory, the outer tangent surfaces of two adjacent cutting edges forming a chip removal groove, one end of the chip removal groove being connected to an annular groove near the outer edge of the shoulder end face among the plurality of annular grooves.

[0007] Furthermore, the friction stir welding head also includes: a clamping part, one end of which is connected to the second end of the intermediate shaft, the clamping part and the stirring needle are spaced apart, the side of the clamping part is provided with a clamping end face, the clamping end face extends along the axial direction of the clamping part, and there are multiple clamping end faces, which are spaced apart along the circumference of the clamping part.

[0008] Furthermore, the stirring needle has a conical structure, and the diameter of the stirring needle is set to gradually decrease along the axial direction away from the shoulder end face.

[0009] Furthermore, the outer circumferential surface of the stirring needle is provided with threads.

[0010] Furthermore, the thread depth is C, and the groove depth of any one of the annular grooves is D, where D≥C.

[0011] Furthermore, the groove includes multiple grooves, which are axially spaced along the shoulder end face.

[0012] Furthermore, the depth of any one of the multiple trenches is E, where E≤D.

[0013] Furthermore, the taper of the stirring needle is B, the projection line of the cutting edge in the plane parallel to the axis of the intermediate shaft is a straight line, and the angle between the straight line and the end face of the shaft shoulder is A, where A < B, 2° ≤ A ≤ 5°.

[0014] Furthermore, the width of any one of the multiple chip removal grooves is set to gradually increase outward along the radial direction of the shoulder end face.

[0015] According to another aspect of the present invention, a friction stir welding apparatus is provided, comprising a friction stir welding head, wherein the friction stir welding head is of the type described above.

[0016] By applying the technical solution of this invention, multiple radially spaced and interconnected annular grooves are provided on the end face of the shaft shoulder. These are combined with multiple cutting edges distributed along an involute trajectory centered on the stirring pin and chip removal grooves formed by the outer tangent surfaces of adjacent cutting edges. The chip removal grooves are connected to the annular grooves near the outer edge of the shaft shoulder. This achieves smooth material flow and efficient chip removal during welding, promotes thorough mixing of materials in the weld area, ensures uniform frictional heat generation between the end face of the shaft shoulder and the workpiece, reduces defects such as weld porosity and inclusions, improves the strength and density of the welded joint, optimizes the cutting effect, extends the service life of the stirring head, and solves the problem of low chip removal efficiency of existing friction stir welding stirring heads in the prior art. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0018] Figure 1 Isometric view of the first embodiment of the friction stir welding head of the present invention;

[0019] Figure 2 A schematic diagram of the second embodiment of the friction stir welding head of the present invention;

[0020] Figure 3 Partial isometric view of the third embodiment of the friction stir welding head of the present invention;

[0021] Figure 4 A partial structural schematic diagram of the fourth embodiment of the friction stir welding head of the present invention;

[0022] Figure 5 A partial structural schematic diagram of the fifth embodiment of the friction stir welding head of the present invention.

[0023] The above figures include the following reference numerals:

[0024] 10. Clamping part; 101. Clamping end face; 20. Intermediate shaft; 201. Chip removal groove; 202. Shaft shoulder end face; 203. Annular groove; 204. Groove; 205. Cutting edge; 206. External tangent; 30. Stirring pin; 301. Thread. Detailed Implementation

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0027] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0028] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of this application is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art. In the drawings, for clarity, the thickness of layers and regions may be exaggerated, and the same reference numerals are used to denote the same devices, and therefore their description will be omitted.

[0029] Friction stir welding (FSW), as a highly efficient and high-quality solid-state welding technology, has been widely used in aerospace, rail transportation, and automotive manufacturing fields due to its advantages such as no melting during the welding process, minimal deformation, and excellent joint performance. It has become one of the core processes for joining lightweight alloys and dissimilar materials. During FSW, the shoulder end face of the stirring head is a key component for generating frictional heat, driving the plastic flow of material in the weld area, and ensuring the quality of the weld formation. Its structural design directly determines the efficiency of heat generation, the flow state of the plastic material, the control effect of welding defects, and the final joint performance.

[0030] However, the existing shoulder end face design of friction stir welding heads still has many shortcomings, making it difficult to meet the requirements of high-precision and high-efficiency welding: First, the shoulder end face mostly adopts a smooth plane, simple annular groove, or disordered cutting structure, lacking a scientific and reasonable material flow guidance design. This leads to the accumulation and blockage of high-temperature plastic material generated by the contact between the shoulder end face and the workpiece during welding, and uneven flow rate due to the lack of a clear flow channel. This prevents the material from fully filling the weld area along the preset path, easily causing defects such as incomplete weld penetration and irregular weld formation. Second, the chip removal structure design is unreasonable. Existing chip removal channels often have narrow cross-sections, disconnected chip removal units, or mismatches between the channel direction and the natural flow direction of the material, resulting in metal chips, oxide scale, and other defects generated during welding. Incompletely plasticized hard particles are difficult to detach quickly from the welding area, causing severe chip blockage. This not only hinders the flow of plastic materials but may also scratch the weld surface or form slag inclusions. Third, smooth end faces or disordered groove layouts result in uneven distribution of the contact friction area between the shoulder end face and the workpiece, leading to significant differences in frictional heat generation efficiency. This results in a dual problem: excessively high local temperatures in the weld area causing coarse grains, and excessively low local temperatures causing insufficient material plasticity, severely affecting the joint density and mechanical properties. Fourth, the lack of scientific arrangement of the cutting edge trajectory makes it impossible to efficiently remove the oxide film at the welding interface and fully break down and refine the material. Furthermore, the lack of smooth connection between the cutting area and the chip removal channel further exacerbates the problems of obstructed material flow and difficult chip removal.

[0031] To address the technical challenges of existing friction stir welding head designs, such as insufficient material flow guidance, low chip removal efficiency, uneven heating, and poor cutting performance, no effective solution has yet been proposed that can achieve synergistic optimization of all functions. A friction stir welding head with scientific flow guidance, efficient chip removal, uniform heating, and precise cutting capabilities is needed to overcome existing technical bottlenecks and improve the welding quality and operational efficiency of friction stir welding.

[0032] This application provides an embodiment of a friction stir welding head, such as... Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, it includes: a stirring needle 30; an intermediate shaft 20, one end of the stirring needle 30 is connected to the first end of the intermediate shaft 20, the first end of the shaft shoulder face 202 is provided with a plurality of annular grooves 203 at the connection between the shaft shoulder face 202 and the stirring needle 30, the plurality of annular grooves 203 are arranged radially at intervals along the shaft shoulder face 202, two adjacent annular grooves 203 are connected by a groove 204, a plurality of cutting edges 205 are provided on the shaft shoulder face, the plurality of cutting edges 205 are arranged around the stirring needle 30 and along an involute trajectory, the outer tangent surface 206 of two adjacent cutting edges 205 forms a chip removal groove 201, one end of the chip removal groove 201 is connected to the annular groove 203 near the outer edge of the shaft shoulder face 202 among the plurality of annular grooves 203.

[0033] By applying the technical solution of this invention, multiple annular grooves 203, which are radially spaced and connected by grooves, are provided at the connection between the shoulder end face 202 of the intermediate shaft 20 and the stirring pin 30. These grooves can effectively accommodate the plastic metal generated during welding and help disperse heat. In conjunction with multiple cutting edges 205 arranged along an involute trajectory with the stirring pin 30 as the center, the oxide film at the welding interface can be efficiently removed and the metal grains can be refined. The chip removal grooves 201 formed by the outer tangent surfaces 206 of adjacent cutting edges 205 are connected to the annular grooves 203 near the outer edge of the shoulder end face 202, thus constructing a smooth chip removal channel. This significantly reduces welding resistance and heat accumulation, improving the forming quality and connection strength of the welded joint, optimizing welding efficiency, and enhancing the overall wear resistance and working stability of the stirring head.

[0034] Furthermore, the friction stir welding head also includes: a clamping part 10, one end of which is connected to the second end of the intermediate shaft 20, the clamping part 10 and the stirring needle 30 are spaced apart, the clamping part 10 is provided with a clamping end face 101 on its side, the clamping end face 101 extends along the axial direction of the clamping part 10, and there are multiple clamping end faces 101, which are spaced apart circumferentially along the clamping part 10.

[0035] By applying the technical solution of the invention, the clamping end faces 101 of the clamping part 10, which are circumferentially spaced and extend axially, can form a stable clamping fit with the welding equipment, effectively preventing circumferential slippage or coaxiality deviation during the operation of the stirring head, and providing reliable support for the stable operation of the intermediate shaft 20 and the stirring pin 30. At the same time, the multiple annular grooves 203 on the shoulder end face 202 of the intermediate shaft 20, which are radially spaced and connected by grooves, can accommodate plastic metal and disperse heat. The cutting edges 205 arranged along the involute with the stirring pin 30 as the center can efficiently break the oxide film and refine the grains. The chip removal grooves 201 formed by the outer tangent surfaces 206 of adjacent cutting edges 205 are connected with the edge annular grooves 203 to achieve smooth chip removal. The synergistic effect of each structure not only improves the forming quality and connection strength of the welded joint, but also reduces the welding resistance. Furthermore, the stable clamping extends the service life of the stirring head, thus optimizing the stability and efficiency of the welding process as a whole.

[0036] Specifically, the stirring pin 30 has a conical structure, and the diameter of the stirring pin 30 is set to gradually decrease along the axial direction away from the shoulder end face.

[0037] By applying the technical solution of the invention, the conical structure of the stirring pin 30, whose diameter gradually decreases along the direction away from the shoulder end face 202, can significantly reduce the initial insertion resistance of welding, penetrate deeper into the weld area more smoothly, and drive the flow of ductile metal. Combined with the stable clamping effect provided by the multiple circumferentially spaced axially extended clamping end faces 101 of the clamping part 10, as well as the radially spaced annular grooves 203 on the shoulder end face 202 of the intermediate shaft 20 connected by grooves, the cutting edges 205 arranged along the involute with the stirring pin 30 as the center, and the chip removal grooves 201 formed by the outer tangent surfaces 206 of adjacent cutting edges 205, it not only further optimizes the efficiency of ductile metal containment, dispersion and discharge, reduces heat accumulation and welding resistance, but also enhances the stirring and mixing effect between the stirring pin 30 and the surrounding metal, improves the density and connection strength of the weld joint, and at the same time, the overall structure works together to ensure the stability of the welding process, extend the service life of the stirring head, and comprehensively optimize the welding quality and efficiency.

[0038] Furthermore, such as Figure 5 As shown, the outer circumferential surface of the stirring needle 30 is provided with a thread 301.

[0039] Applying the technical solution of this invention, the thread 301 provided on the outer peripheral surface of the stirring pin 30 can work synergistically with the tapered structure whose diameter gradually decreases along the direction away from the shoulder end face 202. This further reduces the initial insertion resistance during welding and, through the helical guiding force of the thread 301, strongly drives the plastic metal to flow bidirectionally in both the axial and circumferential directions, significantly improving the uniformity of stirring and mixing. Combined with the stable clamping effect provided by the multiple circumferentially spaced axially extended clamping end faces 101 of the clamping part 10, the radially spaced and grooved annular grooves 203 on the shoulder end face 202 of the intermediate shaft 20... The cutting edges 205 arranged along the involute around the stirring pin 30, and the chip removal groove 201 formed by the outer tangent surfaces 206 of adjacent cutting edges 205, along with the thread 301, can also help guide the plastic metal to the annular groove 203 and the chip removal groove 201, optimizing the efficiency of metal containment and discharge, reducing heat accumulation and welding defects, while enhancing the bonding and stirring effect between the stirring pin 30 and the weld metal, improving the density, connection strength and forming quality of the welded joint. The overall structure works together to ensure the stability of the welding process, extend the service life of the stirring head, and comprehensively improve the welding quality and efficiency.

[0040] Furthermore, the thread depth of thread 301 is C, and the groove depth of any one of the annular grooves 203 is D, where D≥C.

[0041] Applying the technical solution of this invention, the thread depth C of the thread 301 on the outer circumferential surface of the stirring pin 30 and the arbitrary groove depth D of the annular groove 203 on the shoulder end face 202 of the intermediate shaft 20 satisfy D≥C to form a precise fit. This ensures that the plastic metal driven by the thread 301 is fully accommodated by the annular groove 203 without accumulation or overflow. In addition, the diameter of the conical structure of the stirring pin 30 gradually decreases along the direction away from the shoulder end face 202, further reducing the insertion resistance. The helical guiding force of the thread 301 strengthens the bidirectional flow of the plastic metal in both the axial and circumferential directions. Furthermore, the stability provided by the multiple circumferentially spaced axially extended clamping end faces 101 of the clamping part 10 is further enhanced. The clamping effect is achieved by the cutting edges 205 arranged along the involute curve with the stirring pin 30 as the center on the intermediate shaft 20, which efficiently removes the oxide film. The chip removal grooves 201 formed by the outer tangent surfaces 206 of adjacent cutting edges 205 are connected to the edge annular grooves 203. This not only optimizes the efficiency of ductile metal containment, stirring and removal through the adaptation of D≥C, reducing heat accumulation and welding defects, but also enhances the uniformity of stirring and mixing and the density of the weld, significantly improving the connection strength and forming quality of the welded joint. At the same time, the overall structure works together to ensure the stability of the welding process, extend the service life of the stirring head, and comprehensively optimize the welding quality and efficiency.

[0042] In one exemplary embodiment, the groove 204 includes a plurality of grooves 204, which are axially spaced along the shoulder end face 202.

[0043] Applying the technical solution of this invention, in this friction stir welding head, multiple grooves 204 axially spaced along the shoulder end face 202 can further optimize the plastic metal flow path between adjacent annular grooves and grooves 204, allowing the metal driven by the thread depth C of the thread 301 to be evenly dispersed in the annular groove without retention, and the size adaptation of D≥C ensures sufficient capacity; at the same time, the cone-shaped structure of the stirring pin 30 gradually reduces the insertion resistance along the direction away from the shoulder end face 202, the thread 301 enhances the bidirectional flow of metal, and the clamping part Multiple circumferentially spaced axially extended clamping end faces 101 of the 10 ensure stable clamping. Cutting edges 205 arranged along the involute with the stirring pin 30 as the center on the intermediate shaft 20 break the oxide film. Chip removal grooves 201 formed by the outer tangent surfaces 206 of adjacent cutting edges 205 smoothly remove chips. The synergy of these structures not only improves the uniformity of mixing and heat dissipation of ductile metals and reduces welding defects, but also enhances the density and connection strength of the welded joint, ensures the stability of the welding process, extends the service life of the stirring head, and comprehensively optimizes welding quality and efficiency.

[0044] In this embodiment, the depth of any one of the multiple grooves 204 is E, where E≤D.

[0045] Applying the technical solution of this invention, the groove depth E of the groove 204 satisfies E≤D, where D is the groove depth of the annular groove 203. This ensures smooth flow of plastic metal between adjacent annular grooves 203 while maximizing the effective capacity of the annular groove 203, preventing the groove 204 from weakening its metal storage and heat dissipation capabilities due to excessive depth. Furthermore, with D≥C, where C is the thread depth of the thread 301, the tapered structure of the stirring pin 30's thread 301 further reduces the insertion resistance, allowing the plastic metal driven by the thread to be evenly distributed into each annular groove 203 for full storage via the axially spaced grooves 204. The oxide film is efficiently removed by the cutting edges 205 arranged along the involute with the stirring pin 30 as the center on the intermediate shaft 20, and the chip discharge grooves 201 formed by the outer tangent surfaces 206 of adjacent cutting edges 205 are smoothly discharged. The stable clamping effect brought by the multiple circumferentially spaced axially extended clamping end faces 101 of the clamping part 10 is also achieved. The synergy of these structures not only improves the uniformity and flow efficiency of the mixing of ductile metal, reduces heat accumulation and welding defects, but also enhances the density and connection strength of the welded joint, ensures the stability and controllability of the welding process, extends the service life of the stirring head, and comprehensively optimizes the welding quality and efficiency.

[0046] Furthermore, the taper of the stirring needle 30 is B, the projection line of the cutting edge 205 in the plane parallel to the axial direction of the intermediate shaft 20 is a straight line, and the angle between the straight line and the shoulder end face 202 is A, where A < B, 2° ≤ A ≤ 5°.

[0047] Applying the technical solution of this invention, in this friction stir welding head, the taper B of the stirring pin 30 and the projection line of the cutting edge 205 in a plane parallel to the axis of the intermediate shaft 20, along with the angle A between the shoulder end face 202 and the cutting edge 205, satisfy 2°≤A≤5° and A<B, forming a precise fit. This allows the cutting edge 205 to synchronously conform to the weld area with the tapered structure of the stirring pin 30, efficiently breaking the oxide film and refining the grains. Furthermore, the reasonable angle design reduces cutting resistance. Combined with the helical guiding force of the thread depth C of the outer circumferential surface of the stirring pin 30, and the groove depth D≥C of the annular groove 203 and the groove 20… The metal-accommodating and diverting function of the four grooves with depth E≤D and axial spacing, the stable clamping effect brought by the multiple circumferentially spaced axially extended clamping end faces 101 of the clamping part 10, and the smooth chip removal function of the chip removal groove 201 formed by the outer tangent surface 206 of the adjacent cutting edge 205, all work together with the structural, angle, and dimensional parameters to enhance the bidirectional flow and mixing uniformity of the plastic metal, reduce heat accumulation and welding defects, improve the density and connection strength of the welded joint, ensure the stability and controllability of the welding process, extend the service life of the stirring head, and comprehensively optimize the welding quality and efficiency.

[0048] Specifically, the width of any chip removal groove 201 among the multiple chip removal grooves 201 is gradually increased outward along the radial direction of the shoulder end face 202. In this embodiment, the design of the chip removal groove 201 with its gradually increasing width along the radial direction of the shoulder end face 202 forms a smooth chip removal channel that "contracts inward and expands outward." This, combined with the structure of the outer tangent surface 206 of the adjacent cutting edge 205 and the angle adaptation of 2°≤A≤5° and A<B (where A is the angle between the projected line of the cutting edge and the shoulder end face 202, and B is the taper of the stirring pin 30), reduces the flow resistance when plastic metal is discharged, avoids blockage, and accelerates the dissipation of heat with the metal. Simultaneously, the spiral guiding force of the thread depth C of the outer circumferential surface of the stirring pin 30, the low insertion resistance of the tapered structure, and the groove depth D of the annular groove 203 ≥ The metal-accommodating and diverting effect of groove 204 (depth E≤D and axially spaced) and the stable clamping provided by more than 10 circumferentially spaced and axially extended clamping end faces 101 of the clamping part work together to allow the plastic metal driven by the thread 301 to be diverted through the groove 204 to the annular groove 203 for full storage, and then efficiently discharged along the gradually widening chip removal groove 201. This further reduces welding resistance and heat accumulation, enhances the uniformity of plastic metal mixing, reduces defects such as porosity and slag inclusions, improves the density and connection strength of the welded joint, ensures the stability and controllability of the welding process, extends the service life of the stirring head, and comprehensively optimizes welding quality and efficiency.

[0049] According to another specific embodiment of this application, a friction stir welding apparatus is also provided, including a friction stir welding head, wherein the friction stir welding head is the friction stir welding head described in the above embodiment.

[0050] Applying the technical solution of this invention, the friction stir welding equipment fully leverages the synergistic advantages of its various structural, dimensional, and angular parameters: the clamping end faces 101, which are circumferentially spaced and axially extended, ensure a stable connection between the equipment and the stirring head, preventing circumferential slippage or coaxiality misalignment during welding, and providing reliable support for overall operation; the taper B of the conical structure of the stirring pin 30, the tooth depth C of the outer circumferential thread 301, and the angle between the cutting edge 205 are adapted to 2°≤A≤5° and A<B, where A is the angle between the projection line of the cutting edge and the shoulder end face 202. The synergistic effect of the angled joint reduces initial insertion and cutting resistance, while the helical guiding force of the thread 301 enhances the bidirectional flow of ductile metal. This, combined with the cutting edge 205, efficiently removes oxide films and refines grains. The annular groove 203 on the shoulder end face 202 of the intermediate shaft 20, with a depth D≥C, and the axially spaced grooves 204, with a depth E≤D, ensure sufficient containment and uniform distribution of the ductile metal. Furthermore, the chip removal groove 201, which gradually widens radially outward and is formed by the outer tangent surface 206 of adjacent cutting edges 205, significantly reduces chip removal resistance and heat accumulation. These synergistic features result in more uniform mixing of the ductile metal during welding, significantly reducing defects such as porosity and slag inclusions. This leads to a substantial increase in weld joint density and connection strength, while also reducing welding resistance and ensuring a stable and controllable process. This extends the service life of the mixing head and comprehensively optimizes the welding efficiency and operational reliability of the equipment. It is suitable for welding various materials and thicknesses, possessing greater practical value and adaptability.

[0051] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0052] In addition to the above, it should be noted that the terms "one embodiment," "another embodiment," and "embodiment" used in this specification refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this invention.

[0053] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A friction stir welding tool characterized by, Comprising: a stirring needle (30); an intermediate shaft (20), one end of the stirring needle (30) is connected with a first end of the intermediate shaft (20), a shaft shoulder end face (202) of the first end is provided with a plurality of annular grooves (203) at the connection with the stirring needle (30), a plurality of the annular grooves (203) are arranged radially spaced along the shaft shoulder end face (202), two adjacent annular grooves (203) in a plurality of the annular grooves (203) are communicated by a groove (204), a plurality of cutting edges (205) are arranged on the shaft shoulder end face along an involute track with the stirring needle (30) as the center, the outer cutting surfaces (206) of two adjacent cutting edges (205) in a plurality of the cutting edges (205) form a chip flute (201), one end of the chip flute (201) is communicated with the annular groove (203) close to the outer edge of the shaft shoulder end face (202) in a plurality of the annular grooves (203).

2. The friction stir welding tool according to Claim 1, wherein The friction stir welding tool further comprises: a clamping part (10), one end of the clamping part (10) is connected with a second end of the intermediate shaft (20), the clamping part (10) is arranged spaced apart from the stirring needle (30), a clamping end face (101) is arranged on the side of the clamping part (10), the clamping end face (101) extends along the axial direction of the clamping part (10), the clamping end face (101) comprises a plurality of, a plurality of the clamping end faces (101) are arranged circumferentially spaced along the clamping part (10).

3. The friction stir welding tool according to claim 1 or 2, wherein The stirring needle (30) is a conical structure, the diameter of the stirring needle (30) gradually decreases along the axial direction away from the shaft shoulder end face.

4. The friction stir welding tool according to Claim 3, wherein A thread (301) is arranged on the outer peripheral surface of the stirring needle (30).

5. The friction stir welding tool according to Claim 4, wherein The depth of the thread (301) is C, the depth of any one of a plurality of the annular grooves (203) is D, and D≥C.

6. The friction stir welding tool according to Claim 5, wherein The groove (204) comprises a plurality of, a plurality of the grooves (204) are arranged axially spaced along the shaft shoulder end face (202).

7. The friction stir welding tool according to Claim 6, wherein The depth of any one of a plurality of the grooves (204) is E, and E≤D.

8. The friction stir welding tool according to Claim 3, wherein The taper of the stirring needle (30) is B, the projection line of the cutting edge (205) in the plane parallel to the axial direction of the intermediate shaft (20) is a straight line, the angle between the straight line and the shaft shoulder end face (202) is A, and A<B, 2°≤A≤5°.

9. The friction stir welding tool according to Claim 8, wherein The width of any one of a plurality of the chip flutes (201) gradually increases outward along the radial direction of the shaft shoulder end face (202).

10. A friction stir welding apparatus comprising a friction stir welding tool, characterised in that, The friction stir welding tool is the friction stir welding tool according to any one of claims 1-9.

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