Friction stir welding head and friction stir welding machine

Abstract

This utility model relates to a friction stir welding head and a friction stir welding machine. The friction stir welding head includes a shoulder, a stirring pin, and a protective cap, all of which are matched and coaxially arranged in a split structure. The stirring pin includes a needle tip and a column. The protective cap is detachably fixed to the free end of the shoulder. The inner diameter of the axial hole on the protective cap is larger than the outer diameter of the column. On the stirring pin, a plurality of radial grooves are formed near the lower part of the connection between the needle tip and the column, arranged alternately around the circumference. The stirring pin is coaxially arranged with the axial hole, and the radial grooves correspond to the outer side of the outer port edge of the axial hole. This utility model can prevent the stirring pin tip from breaking and directly scratching the shoulder, allowing the shoulder body to be reused for a long time and reducing the cost of use.

Description

Technical Field

[0001] This utility model belongs to the field of friction stir welding technology, specifically relating to a friction stir welding head and a friction stir welding machine. Background Technology

[0002] Friction stir welding (FSW) is a solid-state welding technology. In FSW, a stirring head is inserted into the weld seam and rotates while moving along the weld direction. Friction heat is generated to melt the metal, achieving solid-state welding. The stirring head is the core component of the FSW process. Typically, a FSW stirring head consists of two parts: a stirring pin that inserts into the materials to be welded and a shoulder that clamps the weld seam surface. A clamping handle is integrally formed on the upper part of the shoulder. The stirring pin consists of a column and a needle tip, usually a single-piece structure. Because the needle tip bears a large load during operation, it requires high-performance special materials, resulting in high manufacturing costs. To reduce the overall manufacturing cost of the stirring head, the stirring pin and shoulder are often designed as separate structures, with the shoulder (including the clamping handle) made from a relatively low-cost material.

[0003] However, due to the split structure of the stirring head, the needle breakage often occurs at the root of the needle (near the junction of the column and the needle). Furthermore, the welding equipment continues to move after breakage (welding equipment equipped with a broken needle monitoring mechanism also typically experiences a delay due to a stop), resulting in a small welding feed rate. Because the needle root is close to the shoulder end face, the broken needle can easily scratch the shoulder during the continued movement, rendering the shoulder unusable and causing high operating costs. Utility Model Content

[0004] To reduce usage costs, this utility model provides a friction stir welding head and a friction stir welding machine, which can prevent the stirring needle from breaking and causing direct scratches to the shaft shoulder, allowing the shaft shoulder body to be reused for a long time, thereby achieving the purpose of reducing usage costs.

[0005] The technical solution adopted by this utility model to solve its technical problem is: a friction stir welding head, including a shoulder, a stirring pin and a protective cap that are matched and coaxially arranged in a split structure.

[0006] The stirring needle is a one-piece molded structure that includes a needle head and a cylindrical body. The needle head is conical with a free end at the smaller diameter.

[0007] The protective cap is detachably fixed to the free end of the shaft shoulder. A central hole is formed on the protective cap for the stirring needle to pass through, and the tip of the stirring needle passes downward through the central hole and extends to the outside of the protective cap.

[0008] Multiple radial grooves are formed near the lower part of the junction between the needle and the column, arranged in an alternating circumferential pattern. These radial grooves create a weak point / burst point at the needle root, effectively controlling the area where the stirring needle might break. The inner diameter of the axial bore is larger than the outer diameter of the column, with the junction between the needle and the column located inside the axial bore, and the radial grooves located on the outer edge of the outer port of the axial bore.

[0009] Optionally, the axial spacing between the radial groove (topmost edge) and the junction of the needle and the column is between 3 mm and 8 mm.

[0010] Optionally, the radial groove includes an arc-shaped inner bottom surface, a side bottom surface formed below the inner bottom surface, and a top surface formed above the inner bottom surface. The inner bottom surfaces formed on the multiple radial grooves are arranged in a multi-segment arc shape distributed on the same circumference.

[0011] Both the bottom and top surfaces extend sloping inwards, and the angle between the bottom surface and the radial direction is greater than the angle between the top surface and the radial direction. Furthermore, the radial extension width of the bottom surface is greater than the radial extension width of the top surface.

[0012] The locations where the side bottom surface meets the inner bottom surface, and the locations where the top surface meets the inner bottom surface, are both formed as transition surfaces.

[0013] Optionally, the angle between the side bottom surface and the radial direction is selected between 25 degrees and 40 degrees; the angle between the top surface and the radial direction is selected between 10 degrees and 30 degrees.

[0014] Optionally, on the stirring needle, near the junction of the needle tip and the column, at least one thread is formed above the radial groove, and the radial extension depth of the thread is less than the radial extension depth of the radial groove.

[0015] Optionally, a countersunk hole is formed at the outer end of the axial hole, and the bottom surface of the countersunk hole is formed as a concave arc surface, and the axial depth of the arc surface gradually decreases towards the outer end.

[0016] Optionally, an annular flange is formed inside the protective cap, and the inner ring of the annular flange is formed as part of the axial hole.

[0017] The sidewalls of the protective cap are formed by multiple flanges that are distributed alternately around the circumference and extend axially.

[0018] Multiple slots are formed on the lower sidewall of the shoulder, each corresponding to a flange plate. A cylindrical countersunk hole is formed on the lower end face of the shoulder, corresponding to an annular flange.

[0019] A stud is provided on the rim plate, and the rim plate is fixed in the slot by the stud, while the protective cap is fixedly connected to the shoulder.

[0020] Optionally, the outer peripheral surface of the annular flange and the inner peripheral surface of the cylindrical countersunk hole are formed as prism surfaces that can be plugged into each other.

[0021] Optionally, the axial extension length of the annular flange is less than the axial extension length of the flange plate.

[0022] This utility model also relates to a friction stir welding machine having the above-mentioned friction stir welding head.

[0023] The beneficial effects of this utility model are: the stirring head and stirring friction welding machine provided by this utility model can effectively prevent the stirring needle from breaking and causing direct scratches to the main body of the shoulder, thus enabling the main body of the shoulder to be reused for a long time and achieving the purpose of reducing the cost of use. Attached Figure Description

[0024] Figure 1 This is a partial cross-sectional structural diagram of the present invention.

[0025] Figure 2 This is a top view of the protective helmet.

[0026] Figure 3 This is a schematic diagram of the axial cross-sectional structure of the protective cap.

[0027] Figure 4 This is a schematic diagram of the radial groove formed at the junction of the column and the needle.

[0028] In the figure: 10 Clamping handle; 20 Shoulder; 30 Stirring needle; 31 Needle tip; 311 Radial groove; 3111 Inner bottom surface; 3112 Side bottom surface; 3113 Top surface; 32 Column; 40 Protective cap; 41 Flange; 411 Multi-stage through hole; 412 Stud; 42 Annular flange; 43 End face; 431 Countersunk hole; 44 Shaft hole. Detailed Implementation

[0029] The structures, proportions, and sizes shown in the accompanying drawings are merely for illustrative purposes and to aid those skilled in the art. They are not intended to limit the scope of this invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, provided they do not affect the effectiveness or purpose of this invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, terms such as "upper," "lower," "front," "rear," and "middle" used in this specification are merely for clarity and not intended to limit the scope of this invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of this invention.

[0030] like Figures 1 to 4 The friction stir welding head shown includes a shoulder 20 and a stirring pin 30, which are coaxially arranged in a split structure. The stirring pin 30 includes an integrally formed needle tip 31 and a column 32, with the needle tip being conical and the smaller diameter end being a free end. Typically, the outer diameter (size) of the larger diameter end of the needle tip 31 is the same as the outer diameter (size) of the column 32. After the column 32 of the stirring pin 30 passes through the shaft hole provided on the shoulder 20, it extends upward into the shaft hole on the clamping handle 10 and is fixed therein. The implementation of the aforementioned structural features can be referred to in the prior art, and therefore will not be described in detail.

[0031] The innovation of this application lies in that it also includes a protective cap 40 that is detachably fixed to the free end of the shoulder 20, and a plurality of radial grooves 311 are formed on the lower side (near) of the connection position between the needle 31 and the column 32, which are distributed alternately around the circumference. The axial distance between the uppermost end (edge) of the radial groove 311 and the connection surface between the needle 31 and the column 32 is controlled to be between 3 mm and 8 mm.

[0032] The protective cap 40 is coaxially arranged with the shoulder 20, and the inner diameter of the axial hole 44 formed on the protective cap 40 is larger than the outer diameter of the column 32 (i.e., larger than the outer diameter of the large diameter end of the needle 31), with the diameter difference between the two controlled between 3mm and 6mm. The stirring needle 30 is coaxially arranged with the axial hole 44. The position where the needle 31 connects with the column 32 corresponds to the inside of the axial hole 44, and the radial groove 311 corresponds to the outer side of the outer port edge of the axial hole 44.

[0033] Because a weak point is formed at the root of the needle 31, the needle 31 is likely to break at this weak point. Meanwhile, the inner diameter of the axial hole 44 of the protective cap 40 is larger than the outer diameter of the column 32, and the weak point is close to the lower side of the lower port of the axial hole 44. Therefore, when the needle 31 breaks, it is less likely to scratch the end face 43 of the protective cap 40. Furthermore, (in a few cases) even if the protective cap 40 is scratched, it can be replaced with a new one and continued to be used without needing to replace the main body (including the clamping handle 10) of the shoulder 20. This allows the shoulder 20 to be reused for a long time, thus reducing the cost of use (friction welding).

[0034] In the above scheme, the stirring needle 30 is coaxially and detachably disposed within the shoulder 20, and the needle tip 31 of the stirring needle 30 passes downward through the shoulder 20 and finally extends to the outside of the end face 43 (lower end face) of the protective cap 40. The root of the needle tip 31 is located near the end face 43 of the protective cap 40. A weak position is provided near the root of the needle tip 31 so that the fracture location of the needle tip 31 in the event of breakage during operation is located at the weak position. At the same time, the radial groove formed at the weak position... 311 corresponds to the outer (lower) port edge of the axial hole 44 on the protective cap 40, to ensure that the breakage position of the needle 31 occurs at a distance from the root of the needle 31 and below the end face 43 of the protective cap 40, and at a certain distance from the lower end face of the protective cap 40. In this way, even if the needle breaks and the stirring head does not immediately stop the welding feed, the broken needle 31 will not easily scratch the end face 43 of the protective cap 40, ensuring that the protective cap 40 has a certain possibility of reusability.

[0035] The protective cap 40 effectively protects the shoulder 20, significantly reducing the frequency of replacing the entire shoulder (including the clamping handle 10). Furthermore, it allows for frequent repairs of the shoulder 20 after needle breakage by replacing the protective cap 40, thus reducing operating costs. In addition, the shoulder 20, the stirring needle 30, and the protective cap 40 are all modular (fixed) connections, allowing the shoulder 20 and the protective cap 40 to be made of lower-cost, conventional materials, while the stirring needle 30 can be made of higher-cost, higher-performance materials, further reducing overall manufacturing costs. The protective cap 40 can be understood as part of the shoulder 20.

[0036] Preferably, on the stirring needle 30, near the connection position between the needle tip 31 and the column 32, and corresponding to the radial groove 311, one or two threads (thread grooves) are formed. The radial extension depth of the thread is less than the radial extension depth of the radial groove 311, that is, the groove depth of the thread groove is less than the groove depth of the radial groove 311, and the bottom surface of the thread groove is curved.

[0037] like Figures 1 to 3 As shown, a countersunk hole 431 is formed at the outer port of the axial hole 44, and the bottom surface of the countersunk hole 431 is formed as a concave arc surface, and the axial depth of the arc surface gradually decreases (from the inside) towards the outer port. In this way, when the needle 31 breaks, the countersunk hole 431 can provide clearance to prevent the broken needle from scratching the end face 43 of the protective cap 40.

[0038] An annular flange 42 is formed within the protective cap 40, and the inner ring of the annular flange 42 is formed as part of the axial hole 44. The sidewall of the protective cap 40 is formed as a plurality of flanges 41 that are distributed circumferentially and extend axially.

[0039] A plurality of slots corresponding to the flange plate 41 are formed on the lower part of the side wall of the shoulder 20. A cylindrical countersunk hole that is matched with the annular flange 42 is formed on the lower end face of the shoulder 20.

[0040] Each of the flange plates 41 is provided with a stud 412, which secures the protective cap 40 to the shoulder 20. Specifically, a multi-stage through hole 411 is formed on the flange plate 41, and a threaded countersunk hole is formed on the shoulder 20 and on the bottom surface of the slot. The smooth section of the stud 412 matches the inner end of the inner circumferential surface of the multi-stage through hole 411 in a profile contact manner, and the external threaded section at the end of the stud 412 matches the threaded countersunk hole on the shoulder 20.

[0041] By setting a structure in which the flange plate 41 and the shoulder 20 are fixedly matched, the protective cap 40, after being fixed to the end of the shoulder 20, has good torque resistance and can adapt to the needs of friction welding, making it less likely to fall off from the end of the shoulder 20. To increase the torque resistance of the protective cap 40, improve the stability and reliability of the protective cap 40 fixed to the end of the shoulder 20, and provide all-round protection for the end of the shoulder 20, preferably, the outer peripheral surface of the annular flange 42 is formed as a prism surface (outer prism surface), and correspondingly, the inner peripheral surface of the cylindrical countersunk hole is formed as a prism surface (inner prism surface), and the outer prism surface and the inner prism surface are inserted and matched in a profile contact matching manner.

[0042] like Figure 4As shown, the radial groove 311 includes an arc-shaped inner bottom surface 3111, a side bottom surface 3112 formed at the lower part of the inner bottom surface 3111, and a top surface 3113 formed at the upper part of the inner bottom surface 3111. Both the side bottom surface 3112 and the top surface 3113 extend obliquely from the outside to the inside, and the angle between the side bottom surface 3112 and the radial direction is greater than the angle between the top surface 3113 and the radial direction. Specifically, the angle between the side bottom surface 3112 and the radial direction is selected between 25 degrees and 40 degrees; the angle between the top surface 3113 and the radial direction is selected between 10 degrees and 30 degrees.

[0043] The radial extension width of the side bottom surface 3112 is greater than the radial extension width of the top surface 3113. At the same time, the circumferential extension length of the side bottom surface 3112 is also less than the circumferential extension length of the top surface 3113.

[0044] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit it. Many aspects of this utility model can be improved without departing from the overall concept. Those skilled in the art can modify or change the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A friction stir welding head, comprising a shoulder (20) and a stirring pin (30) arranged coaxially and in a split structure; the stirring pin (30) includes a needle tip (31) and a column (32); characterized in that: It also includes a protective cap (40) that is detachably fixed to the free end of the shoulder (20); The inner diameter of the axial hole (44) on the protective cap (40) is larger than the outer diameter of the column (32); On the stirring needle (30), a plurality of radial grooves (311) are formed near the lower part of the junction of the needle tip (31) and the column (32). The stirring needle (30) is coaxially arranged with the axial hole (44), and the radial groove (311) is located on the outer side of the outer port edge of the axial hole (44).

2. The friction stir welding head according to claim 1, characterized in that: The axial distance between the radial groove (311) and the needle (31) and the column (32) is between 3 mm and 8 mm.

3. The friction stir welding head according to claim 1, characterized in that: The radial groove (311) includes an arc-shaped inner bottom surface (3111), a side bottom surface (3112) formed on the lower part of the inner bottom surface (3111), and a top surface (3113) formed on the upper part of the inner bottom surface (3111). The side bottom surface (3112) and the top surface (3113) are both inclined from the outside to the inside, and the angle between the side bottom surface (3112) and the radial direction is greater than the angle between the top surface (3113) and the radial direction; the radial extension width of the side bottom surface (3112) is greater than the radial extension width of the top surface (3113).

4. The friction stir welding head according to claim 3, characterized in that: The angle between the side bottom surface (3112) and the radial direction is selected between 25 degrees and 40 degrees; the angle between the top surface (3113) and the radial direction is selected between 10 degrees and 30 degrees.

5. The friction stir welding head according to claim 1, characterized in that: On the stirring needle (30), near the junction of the needle tip (31) and the column (32), and corresponding to the radial groove (311), at least one thread is formed; the radial extension depth of the thread is less than the radial extension depth of the radial groove (311).

6. The friction stir welding head according to claim 1, characterized in that: A countersunk hole (431) is formed at the outer port of the axial hole (44), and the bottom surface of the countersunk hole (431) is formed as an inwardly concave arc surface, and the axial depth of the arc surface gradually decreases towards the outer port.

7. The friction stir welding head according to claim 1, characterized in that: An annular flange (42) is formed inside the protective cap (40), and the inner ring of the annular flange (42) is formed as part of the axial hole (44); the sidewall of the protective cap (40) is formed as a plurality of flanges (41) that are distributed around the circumference and extend axially. Multiple slots corresponding to the flange plate (41) are formed on the lower side wall of the shoulder (20); a cylindrical countersunk hole that is matched with the annular flange (42) is formed on the lower end face of the shoulder (20). A stud (412) is provided on the rim plate (41), and the rim plate (41) is fixed to the slot by the stud (412).

8. The friction stir welding head according to claim 7, characterized in that: The outer peripheral surface of the annular flange (42) is formed as a prism surface, the inner peripheral surface of the cylindrical countersunk hole is formed as a prism surface, and the two prism surfaces are connected by a surface contact matching method.

9. The friction stir welding head according to claim 7, characterized in that: The axial extension length of the annular flange (42) is less than the axial extension length of the flange plate (41).

10. A friction stir welding machine, characterized in that: The friction stir welding head includes any one of claims 1 to 9.

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