Feeding auxiliary backfill type friction stir spot welding tool and using method thereof

Abstract

The invention discloses a feeding auxiliary backfill type friction stir spot welding tool, and relates to the technical field of friction stir welding, the feeding auxiliary backfill type friction stir spot welding tool comprises a pressing ring, a stirring sleeve and a stirring needle which are concentrically nested from outside to inside, and a conveying piece is arranged between the stirring sleeve and the stirring needle, so that a gap between the stirring sleeve and the stirring needle forms a directional spiral feeding gap. Compared with the design that a wire feeding hole is formed in the cavity in the prior art, the directional spiral feeding gap is located above the cavity, the risk that the wire is thrown out in the wire conveying process is avoided, the wire can be sheared into particles through the applied axial shearing effect, it is guaranteed that the wire is in a molten state rapidly, and the wire conveying efficiency is improved. And the filling effect at the follow-up spot welding position is good.

Description

Technical Field

[0001] The present invention relates to the technical field of friction stir welding, and particularly relates to a feeding-assisted backfilling friction stir spot welding tool and a using method thereof. Background Art

[0002] Friction stir spot welding is a new type of connection technology developed based on the principle of friction stir welding, which has the advantages of economy, high efficiency, no pollution, and high joint bearing capacity. In the common backfilling friction stir spot welding process, the welding tool consists of a pressure ring, a stirring sleeve, and a stirring pin. The pressure ring is usually located on the outermost side and serves as a reference ring for pressure transmission and positioning; the stirring sleeve is in the middle, wrapping and supporting the stirring pin; the stirring pin is located on the central axis and directly contacts the surface of the workpiece. The three form a "concentric nesting" structure from the outside to the inside, and coaxiality requirements are maintained between the pressure ring and the stirring sleeve, and between the stirring sleeve and the stirring pin.

[0003] During the spot welding process, the chamber generated by the relative movement of the stirring sleeve and the stirring pin can accommodate and receive the molten material of the plate. After that, the backfilling movement of the two can discharge the molten material in the chamber to the solder joint. To achieve the relative movement of the stirring pin and the stirring sleeve, there must be a certain gap for their relative movement between the stirring pin and the stirring sleeve. However, the existence of this gap will cause some molten material to flow into the above gap during the welding process. Affected by the welding process, some molten material of the plate often accumulates in the gap and a small amount of molten material of the plate may adhere to the inside of the gap, resulting in a reduction in the amount of molten material of the plate backfilled to the spot weld. This situation of the lack of molten material of the plate will cause the lack of surface material at the solder joint, resulting in depressions and annular grooves on the surface of the solder joint, affecting the bearing strength and forming aesthetics of the solder joint structure.

[0004] After retrieval, the patent document with the authorization announcement number of CN106825906B discloses a wire-filling backfilling friction stir spot welding method, which includes the following steps:

[0005] Step 1: Zero the welding tool, that is, set the lower surfaces of the stirring pin and the stirring sleeve of the welding tool to the same zero position;

[0006] Step 2: Simultaneously withdraw the stirring pin and the stirring sleeve of the welding tool upward by a certain distance relative to the pressure sleeve of the welding tool. The filling material is placed in the space left by the upward withdrawal of the stirring pin and the stirring sleeve through the wire feeding hole on the pressure sleeve, and the pressure sleeve is brought into contact with the surface of the base material;

[0007] Step 3: The welding process starts, and there are the following two operation modes:

[0008] The first method: the stirring sleeve is rotated at high speed and pressed into the base material, while the stirring needle is retracted upward. Under the stirring and extruding action of the stirring sleeve, the welding area of the base material is plasticized, and the plasticized base material flows into the cavity left by the upward retraction of the stirring needle. Then the stirring sleeve is retracted upward, and the stirring needle is rotated downward, so that the plasticized base material and filling material in the cavity are filled back into the welding area under the stirring and extruding action of the stirring needle.

[0009] The second method: the stirring needle is rotated at high speed and pressed into the base material, while the stirring sleeve is retracted upward. Under the stirring and extruding action of the stirring needle, the welding area of the base material is plasticized, and the plasticized base material flows into the cavity left by the upward retraction of the stirring sleeve. Then the stirring needle is retracted upward, and the stirring sleeve is rotated downward, so that the plasticized base material and filling material in the cavity are backfilled into the welding area under the stirring and extruding action of the stirring sleeve.

[0010] Step 4: Adjust the stirring needle and the stirring sleeve to return to the zero position at the same time. After the stirring needle and the stirring sleeve return to the zero position, continue to rotate on the surface of the weld to allow the plasticized base material and filling material to flow fully, making the surface of the weld smoother and completing the welding process.

[0011] Although the above patent document realizes adding filling material into the chamber through the wire feeding hole to make up for the defect that part of the molten material of the plate is retained in the gap and cannot be backfilled into the spot welding, it can be known from the content disclosed in the patent document and its drawings that the wire feeding hole is arranged at the bottom end of the clamping ring. Subsequently, relying on the wire feeding hole at this position, the feeding filling material is directly placed in the chamber formed by the relative movement of the stirring needle and the stirring sleeve. This direct delivery method will cause the filling material to be located in the chamber as a whole. Subsequently, not only does it take a certain amount of time to act on it to make it molten, but the position of the wire feeding hole is connected to the chamber, so part of the molten filling material may also be thrown out from the wire feeding hole with the rotation of the stirring sleeve and / or the stirring needle, resulting in less filling material actually filled into the chamber, poor filling effect, and subsequent defects may still occur at the spot welding.

[0012] Therefore, we propose a feeding-assisted backfilling friction stir spot welding tool to solve the above problems. Summary of the invention

[0013] The purpose of the present invention is to solve the problems in the prior art and to propose a feeding-assisted backfilling friction stir spot welding tool. The spot welding tool is designed with an inner spiral and / or an outer spiral so that a directional spiral feeding gap is generated between the two to form a conveying channel, and the gap also exerts an axial shearing conveying effect on the wire, so that the wire supplied to the chamber is granular, thereby achieving refined and stable feeding.

[0014] To solve the above problems, the present invention provides the following technical solutions:

[0015] A feeding-assisted backfilling friction stir spot welding tool comprises a clamping ring, a stirring sleeve and a stirring needle which are arranged concentrically from outside to inside, and a conveying member is arranged between the stirring sleeve and the stirring needle so that the gap between the two constitutes a directional spiral feeding gap.

[0016] As a further solution of the present invention: the conveying member includes an inner spiral arranged on the inner wall of the stirring sleeve, and the gap between the inner spiral and the stirring needle constitutes the directional spiral feeding gap.

[0017] As a further solution of the present invention: the conveying member includes an outer spiral arranged outside the stirring needle, and the gap between the outer spiral and the stirring sleeve constitutes the directional spiral feeding gap.

[0018] As a further solution of the present invention: the conveying member includes an inner spiral and an outer spiral respectively arranged on the inner wall of the stirring sleeve and the outside of the stirring needle, the teeth of the inner spiral and the teeth of the outer spiral are in relative conflict with each other, and the directional spiral feeding gap is formed between the two teeth.

[0019] As a further solution of the present invention: when the inner and outer helices have different rotation directions and perform differential rotation in the same direction, and when the inner and outer helices have the same rotation directions and perform differential rotation in opposite directions, the directional spiral feeding gap has an axial shearing and conveying effect that causes the wire located therein to move toward the direction of the chamber.

[0020] As a further solution of the present invention: the sides of the clamping ring and the stirring sleeve are respectively provided with a first channel and a second channel, so that when the first channel and the second channel are connected, the first channel, the second channel and the directional spiral feeding gap are in a connected layout.

[0021] As a further solution of the present invention: the helix angle of the inner helix is the same as the helix angle of the outer helix.

[0022] As a further solution of the present invention: the helix angle of the inner helix is between 15° and 25°.

[0023] As a further solution of the present invention: the ratio of the depth between any two adjacent teeth on the inner spiral to the depth between any two adjacent teeth on the outer spiral is 3:2.

[0024] As a further solution of the present invention: the depth between any two adjacent teeth on the inner spiral is 1.5 mm, and the depth between any two adjacent teeth on the outer spiral is 1 mm.

[0025] As a further solution of the present invention: the bottom end surface of the stirring sleeve is in a layout with the periphery thereof being concave toward the center.

[0026] As a further solution of the present invention: a plurality of through grooves are arranged in a circumferential array at the bottom end of the stirring sleeve.

[0027] The present invention also provides a method for using a feeding-assisted backfilling friction stir spot welding tool, which includes the following steps:

[0028] Step 1: Zeroing: Press the pressing ring onto the plate, and make the bottom ends of the stirring sleeve and the stirring pin located at the same zero position.

[0029] Step 2: Preparation: Simultaneously pull the stirring sleeve and the stirring pin upward by a certain distance, and the space left by the upward pulling of the stirring sleeve and the stirring pin forms a filling area.

[0030] Step 3: Filling: Simultaneously drive the stirring sleeve and the stirring pin to rotate, and make them have a rotational speed difference. Relying on the combined action of the inner helix and the outer helix, an axial shear conveying effect downward is generated in the directional spiral feeding gap. When the positions of the first channel on the pressing ring and the second channel on the stirring sleeve are opposite and connected, the wire can be successively fed into the directional spiral feeding gap through the first channel and the second channel, and is sent to the filling area under the axial shear conveying effect downward.

[0031] Step 4: Welding: Weld the plate by using the stirring sleeve or the stirring pin mode of the spot welding tool.

[0032] Step 5: Ending: After the stirring pin and the stirring sleeve are simultaneously zeroed, continue to rotate on the surface of the solder joint. Relying on the concave and through groove design at the bottom end face of the stirring sleeve, the two types of molten materials flow towards its central position to make the surface of the solder joint smooth and flat.

[0033] As a further scheme of the present invention:

[0034] Stirring sleeve mode: The stirring sleeve rotates and penetrates downward, and the stirring pin rotates and moves upward until the stirring sleeve penetrates to the specified depth of the plate. During this process, the wire is stirred and extruded into a molten state by the stirring sleeve, and there will also be molten material at the penetration position of the plate. Relying on the inner helix on the inner wall of the stirring sleeve to exert an upward pushing effect on the molten wire material and the molten plate material, so that the two types of molten materials are both stored in the space left by the upward movement of the stirring pin. At the same time, relying on the outer helix outside the stirring pin to exert a downward pushing effect on the two types of molten materials, so that the two types of molten materials are limited in the space left by the upward movement of the stirring pin; In the backfilling stage, the stirring sleeve rotates and moves upward, and the stirring pin rotates and moves downward. The two types of molten materials are squeezed downward by the stirring pin to the welding area to form a solder joint.

[0035] As a further scheme of the present invention:

[0036] Stirring needle mode: The stirring needle rotates and penetrates downward, and the stirring sleeve rotates and moves upward until the stirring needle penetrates to the specified depth of the plate. During this process, the wire is stirred and extruded by the stirring needle into a molten state, and there will also be molten material at the penetration position of the plate. The external spiral outside the stirring needle exerts an upward pushing force on the molten wire material and the molten plate material, so that both types of molten materials are stored in the space left by the upward movement of the stirring sleeve. At the same time, the inner spiral on the inner wall of the stirring sleeve exerts a downward pushing force on the two types of molten materials, so that the two types of molten materials are limited in the space left by the upward movement of the stirring sleeve; in the backfilling stage, the stirring needle rotates and moves upward, and the stirring sleeve rotates and moves downward, and the two types of molten materials are squeezed downward by the stirring sleeve to the welding area to form a solder joint.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. The friction stir spot welding tool is based on the concentric nested design of the pressing ring, the stirring sleeve and the stirring needle. When the conveying part is an inner spiral, it relies on the inner spiral for conveying; when the conveying part is an outer spiral, it relies on the outer spiral for conveying; when the conveying part is a combination of an inner spiral and an outer spiral, combined with the relative resistance of the inner and outer spiral teeth, a directional spiral feeding gap is formed. During use, through the differential rotation of the inner and outer spirals, the axial shearing and conveying effect on the wire is realized. The above three designs not only improve the feeding efficiency and stability, but also effectively avoid the problem of material blockage. At the same time, through the directional conveying function of the spiral gap, the path and speed of the wire entering the welding chamber are accurately controlled, providing uniform and controllable filler support for the welding process, thereby improving the welding quality. Compared with the design in the prior art where the wire feeding hole is opened at the chamber, the directional spiral feeding gap in the present application is located above the chamber, and there is no risk of the wire being thrown out during the wire feeding process, and the applied axial shearing effect can shear the wire into particles, ensuring that it quickly becomes molten, so that the filling effect at the subsequent spot welding is better.

[0039] 2. By providing the first channel and the second channel that can be at the same height and aligned on the side of the pressing ring and the stirring sleeve, the modular connection of the feeding path is realized. When the positions of the two channels are opposite, the wire can seamlessly pass through the channels and enter the directional spiral gap, simplifying the feeding process and reducing the operation complexity. This design optimizes the connection between the external material input and the internal spiral conveying, ensures the continuity and accuracy of the filling process, and at the same time reduces the material waste or equipment wear caused by path misalignment.

[0040] 3. The inner spiral and the outer spiral adopt the same spiral lead design, so that they can achieve motion synchronism during differential rotation. This feature ensures the uniformity of the force on the wire in the spiral gap and the consistency of the direction, avoiding problems such as local material accumulation or conveying disorder caused by the difference in the lead angle, thereby improving the conveying efficiency and the uniformity of the distribution of the welding material.

[0041] 4. Limit the spiral lift angle between 15° and 25°, which balances the material conveying efficiency and the mechanical strength of the equipment. A smaller lift angle (such as 15°) can enhance the axial thrust and reduce the risk of material retraction; a larger lift angle (such as 25°) can increase the conveying speed. This range design takes into account the requirements of different working conditions, can not only adapt to the conveying resistance of high-strength materials, but also avoid the problem of easy damage of the mechanical structure caused by too large a lift angle.

[0042] 5. Design the depth of the inner spiral teeth and the outer spiral depth in a ratio of 3:2, and form a stepped conveying effect through the differential tooth structure. The deeper inner spiral teeth can accommodate more materials, while the shallower outer spiral teeth enhance the shearing force on the materials. The synergistic effect of the two improves the material plasticization efficiency and the conveying volume control accuracy, and is especially suitable for the continuous and stable conveying of high-viscosity or easily piled-up materials.

[0043] 6. The structural design of the bottom end face of the stirring sleeve concave from the periphery to the center forms a centripetal flow channel at the welding finishing stage. This concave surface can guide the molten material to converge towards the center of the welding point, effectively eliminating the accumulation of surrounding materials, reducing the defects of surface depression or protrusion of the welding point, and at the same time enhancing the material density, significantly improving the flatness and mechanical properties of the welding point surface.

[0044] 7. The opening of the circumferential through groove at the bottom end of the stirring sleeve further optimizes the material flow path. The through groove can not only assist the uniform diffusion of the molten material, but also timely discharge the gas or impurities generated during the welding process to prevent porosity defects. In addition, the array distribution of the through grooves enhances the dynamic stirring effect of the stirring sleeve on the materials and promotes the homogenization of the material microstructure.

[0045] 8. The usage method of the spot welding tool in this application optimizes the process through zeroing positioning, differential filling and dynamic finishing, giving full play to the structural advantages of the tool. Among them, the rotational speed difference control in step three combined with the downward shearing effect of the spiral gap realizes the precise quantitative conveying of the wire; step five uses the synergistic effect of the concave surface and the through groove to complete the secondary shaping of the molten material to ensure the self-leveling of the welding point surface; throughout the process, through the matching of the structural characteristics and process parameters, the need for manual intervention is reduced, and the welding efficiency and consistency are improved.

[0046] 9. When the spot welding tool of the present application is in use, the inner and outer spirals provided not only play a role in axially shearing and conveying the wire, but also can push the melt upward and limit it downward during the downward penetration stage. Taking the mixing sleeve mode as an example, through the inner spiral provided, during the downward penetration stage, it can play a role in pushing the melt on the plate upward, so that the melt on the plate can enter the space left by the upward movement of the mixing needle and quickly mix with the melt of the wire; at the same time, the outer spiral exerts a downward limiting effect on these two types of mixed melts, effectively preventing the mixed melt from surging upward, so that the mixed melt is limited to the maximum extent in the space left by the upward movement of the mixing needle. In the subsequent backfilling stage, a relatively large amount of the melt in this space can be pushed to the spot welding position, further avoiding depressions and annular grooves on the surface of the solder joint, and achieving a good spot welding treatment effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The present invention will be further described below with reference to the accompanying drawings.

[0048] Figure 1 is a three-dimensional structural schematic diagram of the mixing needle of the present invention;

[0049] Figure 2 is a three-dimensional structural schematic of the mixing sleeve of the present invention Figure 1 ;

[0050] Figure 3 is a three-dimensional structural schematic of the mixing sleeve of the present invention Figure 2 ;

[0051] Figure 4 is a three-dimensional structural schematic diagram of the pressing ring of the present invention;

[0052] Figure 5 is a three-dimensional structural schematic diagram of the assembly of the mixing needle, mixing sleeve and pressing ring of the present invention;

[0053] Figure 6 is a structural schematic diagram of the inner and outer spirals of the present invention;

[0054] Figure 7 is a structural schematic diagram of the working process in the mixing sleeve mode of the present invention.

[0055] In the figure: 1. Pressing ring; 2. Mixing sleeve; 201. Inner spiral; 3. Mixing needle; 301. Outer spiral; 4. First channel; 5. Second channel; 6. Through groove; 7. Directional spiral feeding gap; a. Segmented wire. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0056] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] like Figures 1 - 6 As shown, a feeding-assisted backfilling friction stir spot welding tool comprises a clamping ring 1, a stirring sleeve 2 and a stirring needle 3, which are assembled according to the concentric nesting layout in the prior art. The assembled state can be Figure 5 It is represented by, from outside to inside, there are a clamping ring 1, a stirring sleeve 2 and a stirring needle 3. In this state, the bottom ends of the stirring sleeve 2 and the stirring needle 3 are arranged flush with the bottom end of the clamping ring 1. A conveying member is arranged between the stirring sleeve 2 and the stirring needle 3, so that the gap between the two constitutes a directional spiral feeding gap 7. The formation design of the directional spiral feeding gap 7 can be represented by the following three embodiments:

[0058] Embodiment 1:

[0059] The conveying member includes an inner spiral 201 arranged on the inner wall of the stirring sleeve 2. The gap between the inner spiral 201 and the stirring needle 3 constitutes the above-mentioned directional spiral feeding gap 7. When working, the inner spiral 201 rotates to convey the wire toward the chamber.

[0060] Embodiment 2:

[0061] The conveying member includes an outer spiral 301 arranged outside the stirring needle 3. The gap between the outer spiral 301 and the stirring sleeve 2 constitutes the above-mentioned directional spiral feeding gap 7. When working, the outer spiral 301 rotates to convey the wire toward the chamber.

[0062] Embodiment three:

[0063] The conveying member includes an inner spiral 201 and an outer spiral 301 respectively arranged on the inner wall of the stirring sleeve 2 and the outside of the stirring needle 3, the teeth of the inner spiral 201 and the teeth of the outer spiral 301 are in a state of relative abutment, and the above-mentioned directional spiral feeding gap 7 is formed between the two teeth. In this embodiment, when the inner spiral 201 and the outer spiral 301 have different rotation directions and perform differential rotation in the same direction, and when the inner spiral 201 and the outer spiral 301 have the same rotation direction and perform differential rotation in the opposite direction, the directional spiral feeding gap 7 has an axial shearing conveying effect that causes the wire material located therein to move toward the direction of the chamber.

[0064] As follows, a detailed description is given under the design scenario of the third embodiment:

[0065] An inner spiral 201 is provided on the inner wall of the stirring sleeve 2. This state can beFigure 2 and Figure 3 To represent, an outer spiral 301 is provided on the outside of the stirring needle 3, and this state can be represented by Figure 1 To show that when the stirring sleeve 2 and the stirring needle 3 are Figure 5 In the layout shown in FIG. 1 , the teeth of the inner spiral 201 and the outer spiral 301 are in a state of relative conflict, and a directional spiral feeding gap 7 is formed between the two teeth. Figure 5 When feeding the wire into the directional spiral feeding gap 7, the wire can be fed downward under the shearing action of the inner spiral 201 and the outer spiral 301 until the wire is fed into the chamber formed by the upward movement of the stirring sleeve 2 and the stirring needle 3. In the subsequent welding process, the wire will become molten and mix with the melt of the plate, and act together at the spot welding position.

[0066] For the downward conveying effect generated by the combined action of the inner spiral 201 and the outer spiral 301, when the directional spiral feeding gap 7 is set to the vertical downward direction, it is necessary that the downward conveying effect of the inner spiral 201 is greater than the upward conveying effect of the outer spiral 301, or the downward conveying effect of the outer spiral 301 is greater than the upward conveying effect of the inner spiral 201. Therefore, the present application has two conveying mechanism designs, which can be specifically divided into a stirring sleeve conveying mechanism and a stirring needle conveying mechanism, as follows:

[0067] 1. Mixing sleeve conveying mechanism:

[0068] (1) The inner spiral 201 is set to be left-handed and rotates counterclockwise, and the outer spiral 301 is set to be right-handed and rotates counterclockwise, and the rotation speed of the inner spiral 201 is greater than the rotation speed of the outer spiral 301;

[0069] (2) The inner spiral 201 is set to be left-handed and rotates counterclockwise, and the outer spiral 301 is set to be left-handed and rotates clockwise, and the rotation speed of the inner spiral 201 is greater than the rotation speed of the outer spiral 301;

[0070] (3) The inner spiral 201 is set to be right-handed and rotates clockwise, and the outer spiral 301 is set to be left-handed and rotates clockwise, and the rotation speed of the inner spiral 201 is greater than the rotation speed of the outer spiral 301;

[0071] (4) The inner screw 201 is set to be right-handed and rotates clockwise, and the outer screw 301 is set to be right-handed and rotates counterclockwise, and the rotation speed of the inner screw 201 is greater than the rotation speed of the outer screw 301.

[0072] In summary, when the downward conveying effect of the inner spiral 201 is greater than the upward conveying effect of the outer spiral 301, it means that the net conveying rate Q 净 =Q 套 -Q 针 >0, where Q 套Indicates the downward conveying rate of the stirring sleeve 2 (positively correlated with the rotational speed n of the stirring sleeve 2 套 ), Q 针 Indicates the upward conveying rate of the stirring needle 3 (positively correlated with the rotational speed n of the stirring needle 3 针 ), Q 套 >Q 针 , that is, n 套 >n 针 .

[0073] II. Stirring needle conveying mechanism:

[0074] (1) The outer helix 301 is set to be left-handed and rotates counterclockwise, the inner helix 201 is set to be right-handed and rotates counterclockwise, and the rotational speed of the outer helix 301 is greater than that of the inner helix 201;

[0075] (2) The outer helix 301 is set to be left-handed and rotates counterclockwise, the inner helix 201 is set to be left-handed and rotates clockwise, and the rotational speed of the outer helix 301 is greater than that of the inner helix 201;

[0076] (3) The outer helix 301 is set to be right-handed and rotates clockwise, the inner helix 201 is set to be left-handed and rotates clockwise, and the rotational speed of the outer helix 301 is greater than that of the inner helix 201;

[0077] (4) The outer helix 301 is set to be right-handed and rotates clockwise, the inner helix 201 is set to be right-handed and rotates counterclockwise, and the rotational speed of the outer helix 301 is greater than that of the inner helix 201.

[0078] In summary, when the downward conveying effect of the outer helix 301 is greater than the upward conveying effect of the inner helix 201, it indicates that the net conveying rate Q 净 =Q 针 -Q 套 >0, where Q 套 Indicates the upward conveying rate of the stirring sleeve 2 (positively correlated with the rotational speed n of the stirring sleeve 2 套 ), Q 针 Indicates the downward conveying rate of the stirring needle 3 (positively correlated with the rotational speed n of the stirring needle 3 针 ), Q 针 >Q 套 , that is, n 针 >n 套 .

[0079] Furthermore, since the pressing ring 1, the stirring sleeve 2 and the stirring needle 3 are concentrically nested, the formed directional spiral feeding gap 7 will be located inside the pressing ring 1 and the stirring sleeve 2. In order to realize the feeding of the wire into the directional spiral feeding gap 7, such as Figures 2 - 4As shown, the present application respectively provides a first channel 4 and a second channel 5 on the side parts of the pressing ring 1 and the stirring sleeve 2. After the stirring sleeve 2 and the stirring needle 3 jointly move upward to a specified position, the first channel 4 and the second channel 5 are arranged at the same height at this time. During the rotation of the stirring sleeve 2, the second channel 5 thereon will rotate accordingly. When the first channel 4 rotates to be connected with the position of the second channel 5, the first channel 4, the second channel 5 and the directional spiral feeding gap 7 are in a connected layout. At this time, relying on the first channel 4 and the second channel 5, the wire material can be conveyed into the directional spiral feeding gap 7. Subsequently, under the axial shearing action of the inner spiral 201 and the outer spiral 301, the downward conveyance of the wire material is realized. Therefore, during feeding, the stirring needle 3 and the stirring sleeve 2 are set to a low rotation speed state, and during spot welding, the stirring needle 3 and the stirring sleeve 2 are set to a high rotation speed state. During this low-speed feeding process, the rotation speeds of both the stirring sleeve 2 and the stirring needle 3 are controlled between 5 - 50 rpm (adjusted according to the wire diameter), but it is necessary to ensure that the rotation speed of the stirring sleeve 2 is greater than that of the stirring needle 3. Through this low-speed feeding method, the axial shearing and conveying action formed by the inner spiral 201 and the outer spiral 301 can convey the wire material in the form of particles into the chamber and accumulate it.

[0080] Preferably, in the present application, the inner spiral 201 is set to be left-handed and rotates counterclockwise, the outer spiral 301 is set to be right-handed and rotates counterclockwise, and when the rotation speed of the inner spiral 201 is greater than that of the outer spiral 301, the helix angle of the inner spiral 201 is the same as that of the outer spiral 301, and the helix angles of both are between 15° and 25°. At the same time, the ratio of the depth between any two adjacent teeth on the inner spiral 201 to the depth between any two adjacent teeth on the outer spiral 301 is set to 3:2. For example, when the depth between any two adjacent teeth on the inner spiral 201 is 1.5 mm, the depth between any two adjacent teeth on the outer spiral 301 is 1 mm. Further, laser micro-texture + WS2 solid lubricating coating (friction coefficient ≤ 0.12) is added to the surfaces of both the stirring needle 3 and the stirring sleeve 2.

[0081] Furthermore, in order to avoid unevenness at the spot welding position after the welding work is completed, the bottom end surface of the stirring sleeve 2 in the present application is concavely arranged from the periphery to the center, and this state can be represented by Figure 3 Preferably, the concave angle is 10°; at the same time, a plurality of through grooves 6 are circumferentially arrayed at the bottom end of the stirring sleeve 2. Through the cooperation of the bottom end surface of the stirring sleeve 2 that is concavely arranged from the periphery to the center and the plurality of through grooves 6, the molten material can flow and gather towards the center position of the spot welding position through the through grooves 6, so that the spot welding position is smooth and flat, and no depression or other phenomena will occur, effectively improving the mechanical properties at the spot welding position.

[0082] Embodiment Four:

[0083] Based on the design situation of Embodiment Three, asFigure 7 As shown in the figure, a method for using a feeding-assisted backfill friction stir spot welding tool includes the following steps:

[0084] Step 1: Zeroing: Press the pressing ring 1 onto the plate, and make the bottom ends of the stirring sleeve 2 and the stirring pin 3 both located at the same zeroing position.

[0085] Step 2: Preparation: Simultaneously pull the stirring sleeve 2 and the stirring pin 3 upward by a certain distance, and the space left by the upward pulling of the stirring sleeve 2 and the stirring pin 3 forms a filling area.

[0086] Step 3: Filling: Simultaneously drive the stirring sleeve 2 and the stirring pin 3 to rotate, and make the two have a rotational speed difference. Relying on the combined action of the inner helix 201 and the outer helix 301, the directional spiral feeding gap 7 generates a downward axial shear conveying effect. When the first channel 4 on the pressing ring 1 and the second channel 5 on the stirring sleeve 2 are relatively positioned and connected, the segmented wire a can be sequentially fed into the directional spiral feeding gap 7 through the first channel 4 and the second channel 5, and is sent to the filling area under the downward axial shear conveying effect. This state can be represented by Figure 7 A in the figure.

[0087] Step 4: Welding: Weld the plate using the stirring sleeve 2 or the stirring pin 3 mode of the spot welding tool;

[0088] Stirring sleeve mode: The stirring sleeve 2 rotates and penetrates downward, and the stirring pin 3 rotates and moves upward until the stirring sleeve 2 penetrates to the specified depth of the plate. This state can be represented by Figure 7 B in the figure. During this process, the wire is stirred and extruded into a molten state by the stirring sleeve 2, and there will also be molten material at the penetration position of the plate. At the same time, due to the downward pushing of the stirring sleeve 2, both the wire molten material and the plate molten material will be pushed upward into the space left by the upward movement of the stirring pin 3. During the backfill stage, the stirring sleeve 2 rotates and moves upward, and the stirring pin 3 rotates and moves downward. The two types of molten materials are squeezed downward by the stirring pin 3 to form a solder joint in the welding area. This state can be represented by Figure 7 C in the figure.

[0089] Stirring pin mode: The stirring pin 3 rotates and penetrates downward, and the stirring sleeve 2 rotates and moves upward until the stirring pin 3 penetrates to the specified depth of the plate. During this process, the wire is stirred and extruded into a molten state by the stirring pin 3, and there will also be molten material at the penetration position of the plate. At the same time, due to the downward pushing of the stirring pin 3, both the wire molten material and the plate molten material will be pushed upward into the space left by the upward movement of the stirring sleeve 2; during the backfill stage, the stirring pin 3 rotates and moves upward, and the stirring sleeve 2 rotates and moves downward. The two types of molten materials are squeezed downward by the stirring sleeve 2 to form a solder joint in the welding area.

[0090] Step Five: Finalizing: After the stirring needle 3 and the stirring sleeve 2 return to zero simultaneously, continue to rotate on the surface of the solder joint. Relying on the concave design and the through groove 6 at the bottom end face of the stirring sleeve 2, the two types of molten materials flow towards its central position to make the surface of the solder joint smooth and flat. Then, lift it upward away from the spot welding tool. This state can be represented by Figure 7 D in

[0091] Example Five:

[0092] Based on the spot welding method in Example Four, as shown in Figure 7 , this example is improved on the basis of Example Four, so that the inner helix 201 and the outer helix 301 not only play a role in conveying the wire material during the filling stage, but also can play an additional upward pushing role and an additional downward pushing role on the molten material during the welding process of the corresponding mode. Specifically as follows:

[0093] A method for using a feeding-assisted backfill friction stir spot welding tool includes the following steps:

[0094] Step One: Zeroing: Press the pressing ring 1 on the plate, and make the bottom ends of the stirring sleeve 2 and the stirring needle 3 located at the same zero position.

[0095] Step Two: Preparation: Pull the stirring sleeve 2 and the stirring needle 3 upward simultaneously by a certain distance. The space left by pulling the stirring sleeve 2 and the stirring needle 3 upward forms a filling area.

[0096] Step Three: Filling: Drive the stirring sleeve 2 and the stirring needle 3 to rotate simultaneously, and make them have a rotational speed difference. Relying on the combined action of the inner helix 201 and the outer helix 301, the directional spiral feeding gap 7 generates a downward axial shear conveying effect. When the first channel 4 on the pressing ring 1 and the second channel 5 on the stirring sleeve 2 are relatively positioned and connected, the segmented wire material a can be sent into the directional spiral feeding gap 7 through the first channel 4 and the second channel 5 in sequence, and is sent to the filling area under the downward axial shear conveying effect. This state can be represented by Figure 7 A in

[0097] Step Four: Welding: Weld the plate using the stirring sleeve 2 or the stirring needle 3 mode of the spot welding tool.

[0098] Stirring Sleeve Mode: The stirring sleeve 2 rotates and descends, and the stirring needle 3 rotates and ascends until the stirring sleeve 2 descends to the specified depth of the plate. This state can be represented by Figure 7It is represented by B in Figure 7 . During this process, the wire material is stirred and extruded into a molten state by the stirring sleeve 2, and there will also be molten material at the position where the plate descends. The inner helix 201 on the inner wall of the stirring sleeve 2 applies an upward pushing force to the wire molten material and the plate molten material, so that both types of molten materials are stored in the space left by the upward movement of the stirring needle 3. At the same time, the outer helix 301 outside the stirring needle 3 applies a downward pushing force to the two types of molten materials, so that the two types of molten materials are limited to the space left by the upward movement of the stirring needle 3; In the backfilling stage, the stirring sleeve 2 rotates upward and the stirring needle 3 rotates downward. The two types of molten materials are squeezed downward by the stirring needle 3 to form a solder joint in the welding area. This state can be

[0099] represented by C in

[0100] Stirring needle mode: The stirring needle 3 rotates and descends, and the stirring sleeve 2 rotates upward until the stirring needle 3 descends to the specified depth of the plate. During this process, the wire material is stirred and extruded into a molten state by the stirring needle 3, and there will also be molten material at the position where the plate descends. The outer helix 301 outside the stirring needle 3 applies an upward pushing force to the wire molten material and the plate molten material, so that both types of molten materials are stored in the space left by the upward movement of the stirring sleeve 2. At the same time, the inner helix 201 on the inner wall of the stirring sleeve 2 applies a downward pushing force to the two types of molten materials, so that the two types of molten materials are limited to the space left by the upward movement of the stirring sleeve 2; In the backfilling stage, the stirring needle 3 rotates upward and the stirring sleeve 2 rotates downward. The two types of molten materials are squeezed downward by the stirring sleeve 2 to form a solder joint in the welding area. Figure 7 represented by D in

[0101] It should be noted that during the above filling stage process, the rotation directions of the inner helix 201 and the outer helix 301 only need to satisfy the downward axial conveying effect. In the welding stage process in the stirring sleeve mode, the rotation directions of the inner helix 201 and the outer helix 301 are not restricted by the above. It only needs to satisfy the upward pushing effect of the inner helix 201 on the molten material and the downward pushing effect of the outer helix 301 on the molten material; In the welding stage process in the stirring needle mode, the rotation directions of the inner helix 201 and the outer helix 301 are not restricted by the above. It only needs to satisfy the upward pushing effect of the outer helix 301 on the molten material and the downward pushing effect of the inner helix 201 on the molten material. In summary, the whole composed of the inner helix 201 and the outer helix 301 is independent of each other and does not interfere during the work in the filling stage and the welding stage.

[0102] Taking the stirring sleeve mode as an example, in this embodiment, through the inner spiral 201 provided, during the downward penetration stage, it can play a role in pushing the melt on the plate upward, enabling the plate melt to quickly mix with the wire melt. At the same time, the outer spiral 301 exerts a downward limiting effect on the two types of mixed melts, effectively preventing the mixed melt from surging upward, so that the mixed melt is limited within the space left by the upward movement of the stirring needle 3. In the subsequent backfilling stage, more melt can be pushed to the spot welding position to achieve a good spot welding treatment effect.

[0103] It should be noted that in the design situations of Embodiment 1 and Embodiment 2, the usage methods of Embodiment 1 and Embodiment 2 are roughly the same as those of Embodiment 5, but there are some differences, which are specifically as follows:

[0104] (1) In the case of Embodiment 1, only relying on the rotation of the inner spiral 201 to convey the wire downward.

[0105] (2) In the case of Embodiment 2, only relying on the rotation of the outer spiral 301 to convey the wire downward.

[0106] The above has described in detail an embodiment of the present invention, but the content described is only the preferred embodiment of the present invention and cannot be considered as used to limit the implementation scope of the present invention. All equivalent changes and improvements made according to the scope of the application of the present invention should still fall within the scope covered by the patent of the present invention.

Claims

1. A feeding-assisted backfill friction stir spot welding tool, characterized in that, It comprises a clamping ring (1), a stirring sleeve (2) and a stirring needle (3) which are arranged concentrically from outside to inside, and a conveying member is arranged between the stirring sleeve (2) and the stirring needle (3) so that the gap between the two forms a directional spiral feeding gap (7).

2. The friction stir spot welding tool with feeding-assisted backfilling according to claim 1, characterized in that The conveying member comprises an inner spiral (201) arranged on the inner wall of the stirring sleeve (2), and the gap between the inner spiral (201) and the stirring needle (3) constitutes the directional spiral feeding gap (7).

3. A feeding-assisted backfill friction stir spot welding tool according to claim 1, characterized in that, The conveying member comprises an outer spiral (301) arranged outside the stirring needle (3), and the gap between the outer spiral (301) and the stirring sleeve (2) constitutes the directional spiral feeding gap (7).

4. The feeding-assisted backfill friction stir spot welding tool according to claim 1, characterized in that, The conveying member comprises an inner spiral (201) and an outer spiral (301) which are respectively arranged on the inner wall of the stirring sleeve (2) and the outside of the stirring needle (3); the teeth of the inner spiral (201) and the teeth of the outer spiral (301) are in a state of relative abutment with each other, and the directional spiral feeding gap (7) is formed between the two teeth.

5. A feeding-assisted backfill friction stir spot welding tool according to claim 4, characterized in that, When the inner spiral (201) and the outer spiral (301) have different rotation directions and perform differential rotation in the same direction, and when the inner spiral (201) and the outer spiral (301) have the same rotation direction and perform differential rotation in opposite directions, the directional spiral feeding gap (7) has an axial shearing and conveying effect that causes the wire material located therein to move toward the direction of the chamber.

6. A feeding-assisted backfill friction stir spot welding tool according to any one of claims 1-5, characterized in that, The sides of the clamping ring (1) and the stirring sleeve (2) are respectively provided with a first channel (4) and a second channel (5), so that when the first channel (4) and the second channel (5) are connected, the first channel (4), the second channel (5) and the directional spiral feeding gap (7) are in a connected arrangement.

7. A feeding-assisted backfill friction stir spot welding tool according to any one of claims 1-5, characterized in that, The bottom end surface of the stirring sleeve (2) is arranged in a concave configuration towards the center, and a plurality of through grooves (6) are arranged in a circumferential array at the bottom end of the stirring sleeve (2).

8. A method for using a feeding-assisted backfill friction stir spot welding tool according to any one of claims 1-7, characterized in that, The steps include: Step 1: Zeroing: Press the clamping ring (1) onto the plate, and make the bottom ends of the stirring sleeve (2) and the stirring needle (3) both be at the same zeroing position; Step 2: Preparation: Pull the stirring sleeve (2) and the stirring needle (3) upwards for a certain distance at the same time, and the space left by pulling the stirring sleeve (2) and the stirring needle (3) upwards forms a filling area; Step 3: Filling: The stirring sleeve (2) and the stirring needle (3) are driven to rotate at the same time, and a speed difference is created between the two. The inner spiral (201) and the outer spiral (301) are used together to make the directional spiral feeding gap (7) produce a downward axial shearing and conveying effect. When the first channel (4) on the clamping ring (1) and the second channel (5) on the stirring sleeve (2) are positioned relative to each other and are connected, the wire material can be sequentially fed into the directional spiral feeding gap (7) through the first channel (4) and the second channel (5), and then fed to the filling area under the downward axial shearing and conveying effect. Step 4: Welding: welding the plate using the stirring sleeve (2) or stirring needle (3) mode of the spot welding tool; Step 5: Finishing: After the stirring needle (3) and the stirring sleeve (2) are returned to zero at the same time, they continue to rotate on the surface of the solder joint. Relying on the concave design of the bottom end surface of the stirring sleeve (2) and the through groove (6) design, the two types of molten materials flow toward the center position to make the solder joint surface smooth and flat.

9. The usage method of a feeding-assisted backfilling friction stir spot welding tool according to claim 8, characterized in that: Stirring sleeve mode: The stirring sleeve (2) rotates and descends, and the stirring pin (3) rotates and ascends until the stirring sleeve (2) descends to the specified depth of the plate. During this process, the wire is stirred and extruded into a molten state by the stirring sleeve (2), and there will also be molten material at the descending position of the plate. The inner spiral (201) on the inner wall of the stirring sleeve (2) applies an upward pushing force to the molten wire material and the molten plate material, so that both types of molten materials are stored in the space left by the ascending of the stirring pin (3). At the same time, the outer spiral (301) outside the stirring pin (3) applies a downward pushing force to the two types of molten materials, so that the two types of molten materials are limited to the space left by the ascending of the stirring pin (3); In the backfilling stage, the stirring sleeve (2) rotates and ascends, and the stirring pin (3) rotates and descends. The two types of molten materials are squeezed downward by the stirring pin (3) to the welding area to form a solder joint.

10. The usage method of a feeding-assisted backfilling friction stir spot welding tool according to claim 8, characterized in that: Stirring pin mode: The stirring pin (3) rotates and descends, and the stirring sleeve (2) rotates and ascends until the stirring pin (3) descends to the specified depth of the plate. During this process, the wire is stirred and extruded into a molten state by the stirring pin (3), and there will also be molten material at the descending position of the plate. The outer spiral (301) outside the stirring pin (3) applies an upward pushing force to the molten wire material and the molten plate material, so that both types of molten materials are stored in the space left by the ascending of the stirring sleeve (2). At the same time, the inner spiral (201) on the inner wall of the stirring sleeve (2) applies a downward pushing force to the two types of molten materials, so that the two types of molten materials are limited to the space left by the ascending of the stirring sleeve (2); In the backfilling stage, the stirring pin (3) rotates and ascends, and the stirring sleeve (2) rotates and descends. The two types of molten materials are squeezed downward by the stirring sleeve (2) to the welding area to form a solder joint.

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