Double-shaft-shoulder stirring head

Abstract

The utility model relates to a double-shaft-shoulder stirring head which comprises a stirring needle, an upper shaft shoulder and a lower shaft shoulder. The stirring needle is driven by welding equipment to rotate and axially feed along the butt joint face of a workpiece, and the upper shaft shoulder and the lower shaft shoulder make contact with the upper surface and the lower surface of the workpiece respectively. The upper shaft shoulder is detachable, the upper shaft shoulder and the lower shaft shoulder synchronously press downwards along with the stirring needle, a bidirectional pressure field is formed, it is ensured that a workpiece is evenly pressed in the thickness direction, the stirring needle and a workpiece material severely rub to generate heat, meanwhile, friction between the shaft shoulders and the surface of the workpiece assists in heating, and heat accumulation enables materials near a butt joint face to reach a thermoplastic state. And a dynamic recrystallization superplastic flow layer is formed. The left spiral section and the right spiral section of the stirring needle respectively drive the plastic material to flow towards the middle direction, and the bidirectional spiral structure forms a symmetrical vortex field, so that the material is promoted to be fully mixed in the thickness direction of a welding seam, and the segregation or cavity defect caused by a single flow direction is avoided.

Description

Technical Field

[0001] This utility model relates to the field of friction stir welding technology, specifically to a dual-shoulder stirring head. Background Technology

[0002] Double-shoulder friction stir welding (DS-FSW), as an extension of conventional friction stir welding (FSW) technology, significantly improves the heat input efficiency and material plastic flow uniformity during the welding process by simultaneously contacting the upper and lower shoulders with the workpiece. It is particularly suitable for efficient joining of thick plates, dissimilar materials, or complex structures. Its core principle is that the double-shoulder stirring head rotates at a certain speed and feeds along the workpiece mating surface. The upper and lower shoulders are in close contact with the upper and lower surfaces of the workpiece, respectively. Frictional heat is generated through the intense friction between the shoulders, stirring pins, and the material, as well as the plastic deformation of the material itself, prompting the material near the mating surface to reach a thermoplastic state and achieve metallurgical bonding. However, in existing double-shoulder stirring head designs, the thread structure of the stirring pins is mostly unidirectional spiral. This design may lead to a single flow direction and insufficient symmetry of the material during the welding process, resulting in uneven material distribution and stress concentration in the weld zone, affecting the weld formation quality and mechanical properties. Utility Model Content

[0003] The main purpose of this invention is to provide a dual-shoulder stirring head to solve the problem that in the design of existing dual-shoulder stirring heads, the thread structure of the stirring pin is mostly unidirectional spiral, which may lead to the material flowing in a single direction and lacking symmetry during the welding process.

[0004] To achieve the above objectives, this utility model provides a dual-shoulder stirring head, including a stirring needle, an upper shoulder, and a lower shoulder;

[0005] The stirring needle is a cylindrical threaded rod with a left-handed helical section at one end and a right-handed helical section at the other end. The length of the right-handed helical section is the same as the length of the left-handed helical section.

[0006] One end of the upper shaft shoulder is coaxially connected to one end of the stirring needle with the left spiral section, and the other end is detachably connected to the welding equipment;

[0007] One end of the lower shaft shoulder is coaxially connected to one end of the stirring needle with the right spiral section.

[0008] A preferred embodiment is that multiple arc-shaped grooves are formed around the circumference of both the upper shoulder and the stirring pin contact surface and the lower shoulder and the stirring pin contact surface.

[0009] Multiple arc-shaped grooves extend outward from the stirring needle, centered on the stirring needle.

[0010] A preferred embodiment is that the upper shoulder has a mounting groove along its length for connecting to welding equipment, and the mounting groove is elongated.

[0011] A preferred embodiment is that multiple annular heat dissipation grooves are formed along the length of both the upper and lower shoulder ring walls.

[0012] A preferred embodiment is that the end face of the upper shaft shoulder with the arc-shaped groove is coaxially formed with a shaft hole, the main shaft is inserted into the shaft hole, one end of the main shaft is coaxially connected to one end of the stirring needle with the left spiral section, and the other end is detachably connected to the upper shaft shoulder by a fastener.

[0013] A preferred embodiment is that the fasteners include bolts and nuts;

[0014] A transverse hole is made through the upper shoulder of the shaft, the axis of which is perpendicular to the axis of the upper shoulder and passes through the shaft hole;

[0015] The main shaft has a main hole perpendicular to its axis, and the bolts pass through one end of the transverse hole, the main hole, and the other end of the transverse hole in sequence to be screwed into the nut.

[0016] Both the bolt cap and nut abut against the outer wall of the upper shoulder.

[0017] A preferred embodiment is that stepped grooves are provided at both ends of the transverse hole, and the bolt cap and nut abut against the bottom wall of the two stepped grooves respectively.

[0018] A preferred design is to integrate the spindle and the stirring needle into a single unit.

[0019] The beneficial effects of the above scheme are:

[0020] The stirring pin is driven to rotate by the welding equipment and feeds axially along the workpiece mating surface. The upper and lower shoulders contact the upper and lower surfaces of the workpiece, respectively. The upper shoulder is detachable from the welding equipment, while the lower shoulder presses down synchronously with the stirring pin, forming a bidirectional pressure field to ensure uniform pressure along the workpiece thickness direction. The left and right helical sections of the stirring pin rotate, generating heat through intense friction with the workpiece material. Simultaneously, the friction between the shoulders and the workpiece surface assists in heating. The accumulated heat causes the material near the mating surface to reach a thermoplastic state, forming a dynamically recrystallized superplastic flow layer. The left and right helical sections of the stirring pin drive the plastic material to flow towards the center, and the bidirectional helical structure forms a symmetrical vortex field, promoting thorough mixing of the material along the weld thickness direction and avoiding segregation or void defects caused by unidirectional flow. The upper and lower shoulders continuously apply axial pressure, constraining the volume expansion of the weld zone. The combined effect of the bidirectional pressure field and the stirring pin homogenizes the stress distribution in the plastic flow zone, reducing the risk of residual tensile stress concentration. Attached Figure Description

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0022] Figure 1 This is a three-dimensional structural diagram of the dual-shoulder stirring head of this utility model;

[0023] Figure 2 This is a cross-sectional structural diagram of the dual-shoulder stirring head of this utility model;

[0024] Figure 3 This is a three-dimensional structural diagram of the upper shoulder of the dual-shoulder stirring head of this utility model;

[0025] Figure 4 This is a three-dimensional structural diagram of the lower shoulder and stirring pin of the dual-shoulder stirring head of this utility model.

[0026] Explanation of reference numerals in the attached figures

[0027] 1. Stirring needle; 11. Left spiral section; 12. Right spiral section; 2. Upper shaft shoulder; 21. Mounting groove; 22. Shaft hole; 23. Horizontal hole; 24. Stepped groove; 3. Lower shaft shoulder; 4. Arc-shaped groove; 5. Annular heat dissipation groove; 6. Main shaft; 61. Main hole; 7. Fastener; 71. Bolt; 72. Nut. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Many specific details are set forth in the following description to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0029] Example:

[0030] like Figure 1As shown, this embodiment provides a dual-shoulder stirring head, including a stirring pin 1, an upper shoulder 2, and a lower shoulder 3. The stirring pin 1 is a cylindrical threaded rod, with one end having a left-hand helical segment 11 and the other end having a right-hand helical segment 12, the length of which is the same as the length of the left-hand helical segment 11. One end of the upper shoulder 2 is coaxially connected to the end of the stirring pin 1 with the left-hand helical segment 11, and the upper shoulder 2 has a mounting groove 21 along its length for connection with welding equipment (not shown) in the prior art, the mounting groove 21 being elongated. One end of the lower shoulder 3 is coaxially connected to the end of the stirring pin 1 with the right-hand helical segment 12. Multiple arc-shaped grooves 4 are circumferentially formed on the mating surfaces of the upper shoulder 2 and the stirring pin 1, and on the mating surfaces of the lower shoulder 3 and the stirring pin 1. The multiple arc-shaped grooves 4 extend outward from the stirring pin 1 as the center. The arc-shaped grooves 4 are radially distributed around the stirring pin 1, guiding the plastic material to flow circumferentially and radially within the contact surface between the shoulder and the workpiece. This enhances the uniformity of material mixing and reduces the risk of eddy current defects and void formation, making it particularly suitable for welding thick plates or dissimilar materials. Multiple annular heat dissipation grooves 5 are formed along the length of both the upper shoulder 2 and the lower shoulder 3. These annular heat dissipation grooves 5 facilitate heat dissipation during operation.

[0031] The stirring pin 1 is driven to rotate by the welding equipment and feeds axially along the workpiece mating surface. The upper shoulder 2 and lower shoulder 3 contact the upper and lower surfaces of the workpiece, respectively. The upper shoulder 2 is detachable from the welding equipment, while the lower shoulder 3 presses down synchronously with the stirring pin 1, forming a bidirectional pressure field to ensure uniform pressure in the thickness direction of the workpiece. The left helical section 11 and the right helical section 12 of the stirring pin 1 rotate, generating heat through intense friction with the workpiece material. Simultaneously, the friction between the shoulder and the workpiece surface assists in heating. The accumulated heat causes the material near the mating surface to reach a thermoplastic state, forming a dynamically recrystallized superplastic flow layer. The left helical section 11 and the right helical section 12 of the stirring pin 1 drive the plastic material to flow towards the center. The bidirectional helical structure forms a symmetrical vortex field, promoting thorough mixing of the material in the weld thickness direction and avoiding segregation or void defects caused by a single flow direction. The upper shoulder 2 and the lower shoulder 3 continuously apply axial pressure, constraining the volume expansion of the weld area. The combined effect of the bidirectional pressure field and the stirring pin 1 homogenizes the stress distribution in the plastic flow zone, reducing the risk of residual tensile stress concentration.

[0032] like Figures 1-4 As shown, the upper shoulder 2 has an arc-shaped groove 4, and a shaft hole 22 is coaxially formed on its end face. A main shaft 6 is inserted into the shaft hole 22. One end of the main shaft 6 is coaxially connected to one end of the stirring needle 1 with a left-hand spiral section 11. The other end of the main shaft 6 is detachably connected to the upper shoulder 2 via a fastener 7. The fastener 7 includes a bolt 71 and a nut 72. For example... Figure 2 , Figure 3As shown, a transverse hole 23 is formed through the upper shoulder 2. The axis of the transverse hole 23 is perpendicular to the axis of the upper shoulder 2, and the transverse hole 23 passes through the shaft hole 22. Figure 4 As shown, the main shaft 6 has a main hole 61 perpendicular to its axial direction. A bolt 71 passes sequentially through one end of the transverse hole 23, the main hole 61, and the other end of the transverse hole 23, and is screwed onto a nut 72. Both the bolt cap of the bolt 71 and the nut 72 abut against the outer wall of the upper shoulder 2. Stepped grooves 24 are formed at both ends of the transverse hole 23, and the bolt cap of the bolt 71 and the nut 72 abut against the bottom wall of the two stepped grooves 24 respectively. The main shaft 6 and the stirring needle 1 form an independent structure through coaxial connection. Only the transversely positioned bolts 71 need to be loosened to remove the main shaft 6 and stirring needle 1 assembly as a whole, and replace them with pre-installed stirring needles of different specifications. The main shaft 6 and the stirring needle 1 are an integral structure. This integral structure increases the stability of the structure.

[0033] Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

Claims

1. A dual-shouldered mixing head characterized by, include: A stirring needle, wherein the stirring needle is a cylindrical threaded rod, one end of the cylindrical threaded rod has a left-handed helical section and the other end has a right-handed helical section, the length of the right-handed helical section being the same as the length of the left-handed helical section; The upper shaft shoulder has one end coaxially connected to one end of the stirring needle with a left helical section, and the other end is detachably connected to the welding equipment. The lower shoulder is coaxially connected to one end of the stirring needle with a right-hand spiral section.

2. The dual-shoulder stirring head according to claim 1, characterized in that, Multiple arc-shaped grooves are formed on the circumference of both the upper shoulder and the stirring pin contact surface, as well as the lower shoulder and the stirring pin contact surface. The plurality of the arc-shaped grooves extend outward from the end face centered on the stirring needle.

3. The dual-shoulder stirring head according to claim 2, characterized in that, The upper shoulder has a mounting groove along its length for connecting with the welding equipment, and the mounting groove is elongated.

4. The dual-shoulder stirring head according to claim 1, characterized in that, Multiple annular heat dissipation grooves are formed along the length of both the upper and lower shoulder ring walls.

5. The dual-shoulder stirring head according to any one of claims 1-4, characterized in that, The upper shaft shoulder has an arc-shaped groove on its end face, and a shaft hole is coaxially formed therein. A main shaft is inserted into the shaft hole. One end of the main shaft is coaxially connected to one end of the stirring needle with a left-hand spiral section, and the other end is detachably connected to the upper shaft shoulder by a fastener.

6. The dual-shoulder stirring head according to claim 5, characterized in that, The fasteners include bolts and nuts; A transverse hole is formed through the upper shoulder, the axis of the transverse hole is perpendicular to the axis of the upper shoulder, and passes through the shaft hole; The main shaft has a main hole that extends perpendicularly through its axis, and the bolt passes through one end of the transverse hole, the main hole, and the other end of the transverse hole in sequence and is screwed into the nut. Both the bolt cap and the nut abut against the outer wall of the upper shoulder.

7. The dual-shoulder stirring head according to claim 6, characterized in that, Both ends of the transverse hole are provided with stepped grooves, and the bolt cap and the nut abut against the bottom wall of the two stepped grooves respectively.

8. The dual-shoulder stirring head according to claim 5, characterized in that, The main shaft and the stirring needle are an integral structure.

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