Horn-shaped backfill type friction stir spot welding tool

Abstract

The utility model discloses a trumpet-shaped backfill type friction stir spot welding tool, which relates to the technical field of welding and comprises a stirring needle and a stirring sleeve which is positioned outside the stirring needle and has a working gap with the stirring needle, a matching hole shoulder is arranged on the inner wall of the stirring sleeve in the direction of the stirring needle in a protruding mode, a matching shaft shoulder is arranged on a stirring needle shaft body between the matching hole shoulder and a welding spot in a protruding mode, and a temporary containing area used for containing melt is formed in the area between the matching hole shoulder and the matching shaft shoulder. And the melt in the temporary containing area is extruded to the welding spot. According to the welding tool, the matching hole shoulder and the matching shaft shoulder are arranged, the temporary containing area capable of containing melt is formed between the matching hole shoulder and the matching shaft shoulder, after the welding tool conducts welding action, the axial approaching action of the matching hole shoulder and the matching shaft shoulder can drive the temporary containing area to be gradually reduced, and then the melt in the temporary containing area is extruded and discharged to a welding spot; and a good welding compact effect at a welding spot is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of welding, in particular to a trumpet-shaped backfill friction stir spot welding tool. Background Art

[0002] Lightweight materials such as aluminum alloys, magnesium alloys, and titanium alloys, as well as dissimilar material combinations based on these lightweight materials (e.g., aluminum / copper, aluminum / titanium, aluminum-iron, and aluminum / magnesium), have demonstrated broad application potential in a variety of fields, including aerospace and vehicle manufacturing. These materials, due to their unique microstructures and structural characteristics, as well as differences in physical and chemical properties, present unprecedented challenges to modern joining techniques. Friction stir welding, a novel solid-state welding technique invented by the UK Welding Institute in 1991, is hailed as the most representative green welding technology since the advent of laser welding. Compared with traditional fusion welding, friction stir welding (FSW) exhibits minimal microstructural changes in the heat-affected zone (HAZ) of welded joints, lowers residual stresses, reduces deformation of the welded workpiece, and eliminates defects such as porosity. However, the presence of the stirring needle in FSW inevitably leaves a keyhole on the workpiece surface, often acting as a stress concentration point in the joint, thus compromising joint performance. To address this issue, the German GKSS Center proposed a new solid-state welding technique, backfill FSW, in 2002, based on the principles of FSW.

[0003] The backfill friction stir spot welding tool mainly consists of three parts: a stirring pin, a stirring sleeve that is movably mounted on the outside of the stirring pin, and a clamping ring that is mounted on the outside of the stirring sleeve. The stirring sleeve and the stirring pin can both perform independent relative reciprocating motion under the action of corresponding driving sources. During the spot welding process, the gap between the stirring sleeve and the stirring pin will be filled with molten material, and the backfilling motion of the two can discharge the molten material in the gap to the weld point. In order to achieve the relative movement of the stirring pin and the stirring sleeve, a certain gap must be left between the stirring pin and the stirring sleeve. This causes part of the molten material to fill the above gap during the welding process, causing the welding tool to be blocked and affecting subsequent welding.

[0004] In order to solve the problem of easy clogging of the above-mentioned welding tools, the internal structure of the existing welding tools is generally designed to be a thin-waist drum type, that is, a structure that is thin in the middle and wide at both ends. However, the design of this structure will cause a large amount of molten material to be filled in the gap between the stirring needle and the stirring sleeve. The backfilling movement of the stirring needle and the stirring sleeve cannot completely discharge the molten material to the weld point, resulting in poor welding effect at the weld point. At the same time, part of the molten material will remain in the gap and gradually harden. After multiple spot welding operations are performed continuously, a large amount of molten material will harden and fill the gap. Once the gap between the stirring needle and the stirring sleeve is filled with the molten material, the stirring needle will be squeezed by the molten material, that is, during the subsequent spot welding operation, the axial resistance encountered by the stirring needle during movement will increase, the movement accuracy will be affected, and the stability of the weld point obtained under the same parameters will become worse. In addition, if the movement resistance encountered by the stirring needle is large, it may break, which reduces the service life of the stirring needle.

[0005] Therefore, we propose a trumpet-shaped backfill friction stir spot welding tool to solve the problems in the prior art. Utility Model Content

[0006] The purpose of the utility model is to solve the problems in the prior art and to propose a trumpet-shaped backfill friction stir spot welding tool. The tool improves the structure of the stirring needle and the stirring sleeve so that a temporary holding area of ​​a special shape is formed between the two. When the stirring needle and the stirring sleeve perform a backfilling movement, the molten material inside the storage gap can be completely discharged to the weld point, which not only improves the density of the weld point, but also improves the welding accuracy and the service life of the stirring needle.

[0007] In order to solve the above problems, the present invention provides the following technical solutions:

[0008] A trumpet-shaped backfill friction stir spot welding tool comprises a stirring pin and a stirring sleeve located outside the stirring pin and having a working gap therebetween; a mating hole shoulder is protruding from the inner wall of the stirring sleeve toward the stirring pin, a mating shaft shoulder is protruding from the stirring pin shaft between the mating hole shoulder and the welding point, and the area between the mating hole shoulder and the mating shaft shoulder constitutes a temporary holding area for accommodating the melt, thereby utilizing the axial extrusion action between the mating hole shoulder and the mating shaft shoulder to squeeze the melt in the temporary holding area to the welding point.

[0009] As a further solution of the present invention: the stirring sleeve is composed of a flared portion and a cylindrical portion that are coaxially connected, and the inner wall of the connection between the flared portion and the cylindrical portion is tapered to form the matching hole shoulder.

[0010] As a further solution of the present invention: the stirring needle consists of an upper connecting section and a lower working section, and the outer wall of the connection between the upper connecting section and the lower working section is conically set to form the mating shoulder, and the taper of the mating shoulder is the same as the taper of the mating hole shoulder to achieve an oblique wedge mating arrangement of the two.

[0011] As a further solution of the present invention: the flared portion and the barrel portion are arranged sequentially from bottom to top, the diameter of the upper connecting section is smaller than the diameter of the lower working section, and the upper connecting section and the lower working section are respectively located in the barrel portion and the flared portion.

[0012] As a further solution of the present invention: the flared portion and the barrel portion are arranged sequentially from top to bottom, the diameter of the upper connecting section is larger than the diameter of the lower working section, and the upper connecting section and the lower working section are respectively located in the flared portion and the barrel portion.

[0013] As a further solution of the present invention: the stirring needle and the stirring sleeve are coaxially arranged.

[0014] Furthermore, the present invention also provides a welding device, which includes the above-mentioned trumpet-shaped backfill friction stir spot welding tool.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. By setting up the matching hole shoulder and the matching shaft shoulder, a temporary holding area that can accommodate the molten material is formed between the two. When the welding tool is doing welding backfill, the axial close movement of the matching hole shoulder and the matching shaft shoulder can drive the temporary holding area to gradually become smaller, thereby squeezing the molten material inside the temporary holding area to be discharged to the welding point, ensuring a good welding density effect at the welding point;

[0017] 2. By setting the taper of the mating shaft shoulder and the taper of the mating hole shoulder to be the same, when the two are arranged in an oblique wedge fit, the molten material inside the temporary accommodation area can be completely squeezed to the weld point, which not only makes the weld point denser, but also makes the molten material inside the temporary accommodation area completely discharged, thus preventing the molten material from solidifying in the temporary accommodation area and affecting the subsequent welding effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below with reference to the accompanying drawings.

[0019] Figure 1 This is a schematic cross-sectional view of the first embodiment of the present invention;

[0020] Figure 2 yes Figure 1 Schematic diagram of the assembly structure in;

[0021] Figure 3 This is a schematic cross-sectional view of the stirring sleeve in the first embodiment of the present invention;

[0022] Figure 4 yes Figure 1 In the state, the cross-sectional structural diagram of the stirring needle moving downward and the stirring sleeve moving upward;

[0023] Figure 5 This is a schematic diagram of the working state structure of the first embodiment of the utility model Figure 1 ;

[0024] Figure 6 This is a schematic diagram of the working state structure of the first embodiment of the utility model Figure 2 ;

[0025] Figure 7 This is a schematic cross-sectional view of the second embodiment of the present invention;

[0026] Figure 8 yes Figure 7 Schematic diagram of the assembly structure in;

[0027] Figure 9 This is a schematic cross-sectional view of the stirring sleeve in the second embodiment of the present invention;

[0028] Figure 10 yes Figure 7 Schematic diagram of the cross-sectional structure of the stirring needle moving upward and the stirring sleeve moving downward in the state;

[0029] Figure 11 This is a schematic diagram of the working state structure of the second embodiment of the utility model Figure 1 ;

[0030] Figure 12 This is a schematic diagram of the working state structure of the second embodiment of the utility model Figure 2 .

[0031] In the figure: 1, stirring needle; 101, upper connecting section; 102, lower working section; 2, stirring sleeve; 201, flaring portion; 202, barrel; 3, clamping ring; 4, temporary holding area; a, plate to be welded; b, melt. DETAILED DESCRIPTION

[0032] The following will be combined with the accompanying 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 embodiments described 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 making creative efforts are within the scope of protection of the present invention.

[0033] A trumpet-shaped backfill friction stir spot welding tool comprises a stirring needle 1, a stirring sleeve 2 arranged outside the stirring needle 1, and a clamping ring 3 arranged outside the stirring sleeve 2. The stirring needle 1 and the stirring sleeve 2 are coaxially arranged. The stirring needle 1 can rotate and move back and forth relative to the stirring sleeve 2. The stirring sleeve 2 can rotate and move back and forth relative to the clamping ring 3. The stirring needle 1 and the stirring sleeve 2 move independently without interfering with each other. A working gap is formed between the stirring needle 1 and the stirring sleeve 2. The above is a conventional arrangement in the prior art. Specifically, the innovative arrangement of the present invention is as follows: a mating hole shoulder is protruded from the inner wall of the stirring sleeve 2 toward the stirring needle 1, a mating shaft shoulder is protruded from the shaft body of the stirring needle 1 between the mating hole shoulder and the welding point, and the area between the mating hole shoulder and the mating shaft shoulder constitutes a temporary holding area 4 for accommodating the melt b, so that by utilizing the axial extrusion action between the mating hole shoulder and the mating shaft shoulder, the temporary holding area 4 formed between the two gradually becomes smaller, and the melt b in the temporary holding area 4 will be squeezed out to the welding point. When more of the melt b is located at the welding point, the density of the welding point will be good, thereby improving the welding effect.

[0034] Example 1:

[0035] like Figures 1-6 As shown, the stirring sleeve 2 is composed of a flared portion 201 and a cylindrical portion 202 that are coaxially connected, and the inner wall of the flared portion 201 and the cylindrical portion 202 is tapered to form a mating shoulder. The stirring needle 1 is composed of an upper connecting section 101 and a lower working section 102, and the outer wall of the upper connecting section 101 and the lower working section 102 is tapered to form a mating shoulder. Based on this arrangement, in order to completely discharge the molten material b inside the temporary holding area 4 to the weld point when the mating shoulder and the mating shoulder move axially, the taper of the mating shoulder can be set to the same as the taper of the mating shoulder, so as to achieve a final wedge-fit arrangement of the two.

[0036] Specifically, the flared portion 201 and the cylindrical portion 202 are arranged sequentially from bottom to top, the diameter of the upper connecting section 101 is smaller than the diameter of the lower working section 102, and the upper connecting section 101 and the lower working section 102 are respectively located in the cylindrical portion 202 and the flared portion 201.

[0037] Stirring needle mode welding process:

[0038] (1) The initial state of the stirring needle 1 and the stirring sleeve 2 is as follows Figure 1 As shown, the stirring needle 1 and the stirring sleeve 2 in this state are in contact with the plate a to be welded;

[0039] (2) Drive the stirring needle 1 to rotate and move downward, drive the stirring sleeve 2 upward, and the temporary holding area 4 becomes larger. In this state, the melt b at the stirring needle 1 will flow into the temporary holding area 4. At this time, Figure 5 To express;

[0040] (3) When the stirring needle 1 moves downward to the specified depth on the plate a to be welded, the temporary holding area 4 is filled with the molten material b. At this time, the stirring needle 1 moves upward and the stirring sleeve 2 moves downward. The temporary holding area 4 gradually becomes smaller as the mating shaft shoulder and the mating hole shoulder approach each other, and the molten material b inside the temporary holding area 4 is discharged to the weld point. This state can be represented by Figure 6 To represent; when the mating shaft shoulder and the mating hole shoulder are finally arranged in an oblique wedge fit state, the molten material b inside the temporary holding area 4 will be completely discharged to the welding point to complete the welding work.

[0041] Example 2:

[0042] like Figure 7-12 As shown, the stirring sleeve 2 is composed of a flared portion 201 and a cylindrical portion 202 that are coaxially connected, and the inner wall of the flared portion 201 and the cylindrical portion 202 is tapered to form a mating shoulder. The stirring needle 1 is composed of an upper connecting section 101 and a lower working section 102, and the outer wall of the upper connecting section 101 and the lower working section 102 is tapered to form a mating shoulder. Based on this arrangement, in order to completely discharge the molten material b inside the temporary holding area 4 to the weld point when the mating shoulder and the mating shoulder move axially, the taper of the mating shoulder can be set to the same as the taper of the mating shoulder, so as to achieve a final wedge-fit arrangement of the two.

[0043] Specifically, the flared portion 201 and the cylindrical portion 202 are arranged sequentially from top to bottom, the diameter of the upper connecting section 101 is larger than the diameter of the lower working section 102, and the upper connecting section 101 and the lower working section 102 are respectively located in the flared portion 201 and the cylindrical portion 202.

[0044] Stirring sleeve mode welding process:

[0045] (1) The initial state of the stirring needle 1 and the stirring sleeve 2 is as follows Figure 7 As shown, the stirring needle 1 and the stirring sleeve 2 in this state are in contact with the plate a to be welded;

[0046] (2) The stirring sleeve 2 is driven to rotate and move downward, and the stirring needle 1 is driven upward, and the temporary holding area 4 becomes larger. In this state, the melt b at the stirring sleeve 2 will flow into the temporary holding area 4. At this time, Figure 11 To express;

[0047] (3) When the stirring sleeve 2 moves downward to the specified depth on the plate a to be welded, the temporary holding area 4 is filled with the molten material b. At this time, the stirring sleeve 2 moves upward and the stirring needle 1 moves downward. The temporary holding area 4 gradually becomes smaller as the mating shaft shoulder and the mating hole shoulder approach each other, and the molten material b inside the temporary holding area 4 is discharged to the welding point. This state can be represented by Figure 12 To illustrate, when the mating shaft shoulder and the mating hole shoulder are finally arranged in an oblique wedge fit, the molten material b inside the temporary holding area 4 will be completely discharged to the welding point, completing the welding work.

[0048] It can be seen from the first and second embodiments and the corresponding drawings that the temporary holding area 4 formed between the stirring needle 1 and the stirring sleeve 2 is generally in the shape of a trumpet.

[0049] Example 3:

[0050] A welding device includes the trumpet-shaped backfill friction stir spot welding tool in any of the above embodiments. Furthermore, the device may also include a three-dimensional motion mechanism, a power supply, etc. required during use.

[0051] The above describes an embodiment of the present invention in detail. However, the above content is only a preferred embodiment of the present invention and should not be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent application of the present invention.

Claims

1. A trumpet-shaped backfill friction stir spot welding tool, comprising a stirring pin (1) and a stirring sleeve (2) located outside the stirring pin (1) and having a working gap between the stirring pin (1) and the stirring sleeve, characterized in that: A matching hole shoulder is provided on the inner wall of the stirring sleeve (2) in the direction of the stirring needle (1), and a matching shaft shoulder is provided on the shaft of the stirring needle (1) between the matching hole shoulder and the welding point. The area between the matching hole shoulder and the matching shaft shoulder constitutes a temporary holding area (4) for accommodating the melt (b), so that the melt (b) in the temporary holding area (4) is squeezed to the welding point by utilizing the axial extrusion action between the matching hole shoulder and the matching shaft shoulder.

2. A trumpet-shaped backfill friction stir spot welding tool according to claim 1, characterized in that: The stirring sleeve (2) is composed of a flared portion (201) and a cylindrical portion (202) that are coaxially connected, and the inner wall of the connection between the flared portion (201) and the cylindrical portion (202) is tapered to form the matching hole shoulder.

3. A trumpet-shaped backfill friction stir spot welding tool according to claim 2, characterized in that: The stirring needle (1) is composed of an upper connecting section (101) and a lower working section (102), and the outer wall of the connection between the upper connecting section (101) and the lower working section (102) is tapered to form the matching shoulder, and the taper of the matching shoulder is the same as the taper of the matching hole shoulder, so as to realize the oblique wedge matching arrangement of the two.

4. A trumpet-shaped backfill friction stir spot welding tool according to claim 3, characterized in that: The flared portion (201) and the cylindrical portion (202) are arranged sequentially from bottom to top, the diameter of the upper connecting section (101) is smaller than the diameter of the lower working section (102), and the upper connecting section (101) and the lower working section (102) are respectively located in the cylindrical portion (202) and the flared portion (201).

5. The trumpet-shaped backfill friction stir spot welding tool according to claim 3, characterized in that: The flared portion (201) and the cylindrical portion (202) are arranged sequentially from top to bottom, the diameter of the upper connecting section (101) is larger than the diameter of the lower working section (102), and the upper connecting section (101) and the lower working section (102) are respectively located in the flared portion (201) and the cylindrical portion (202).

6. The trumpet-shaped backfill friction stir spot welding tool according to claim 1, characterized in that: The stirring needle (1) and the stirring sleeve (2) are coaxially arranged.

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