A dual hydraulic drive backfilling stirring friction spot welding equipment

Abstract

This invention discloses a dual-hydraulic-driven backfill friction stir spot welding device, relating to the field of friction stir spot welding technology. It includes an electric spindle and a welding fixture composed of a stirring pin, a stirring sleeve, and a clamping sleeve. The device also includes a stirring pin drive system and a stirring sleeve drive system for driving the stirring pin and stirring sleeve axially, respectively. The stirring pin drive system, the stirring sleeve drive system, and the electric spindle are coaxially arranged and coincide with the rotation center of the welding fixture. The electric spindle drives the stirring pin and the stirring sleeve to rotate. The power source for the stirring pin drive system and the stirring sleeve drive system is a hollow rotary hydraulic cylinder. This invention, through its coaxial control structure, can eliminate the bending moment caused by the off-axis. Furthermore, it eliminates the need to embed the lead screw and motor inside the spindle; instead, the hydraulic cylinder inside the spindle is driven by an external hydraulic station. The structure is compact and easily achieves coaxial control.

Description

Technical Field

[0001] This invention relates to the field of friction stir spot welding technology, specifically to a dual hydraulic drive backfill friction stir spot welding device. Background Technology

[0002] Friction stir spot welding (FSW) is a novel solid-state welding technology developed based on friction stir welding (FSW) technology. FSW can form lap joints similar to resistance spot welding and riveting, offering advantages such as high joint quality, stable weld quality, minimal deformation, and high energy efficiency, effectively overcoming the shortcomings of resistance spot welding and riveting. The emergence of backfill-type FSW has successfully solved the problem of keyholes remaining in the center of the weld after traditional FSW, allowing for the production of keyhole-free lap joints with superior mechanical properties in a single operation. This results in high production efficiency and ease of automation.

[0003] In existing technologies, the driving modes of the stirring needle and the stirring sleeve are both off-axis driven, which is prone to generating bending moments. Using a motor drive also results in problems such as non-compact structure and difficulty in achieving coaxial control. To address these issues, we propose a dual hydraulic drive backfill stirring friction spot welding device. Summary of the Invention

[0004] The purpose of this invention is to provide a dual-hydraulic-driven backfill friction stir spot welding device. An external hydraulic station drives the internal hydraulic pressure of the main shaft, primarily through two hollow rotary hydraulic cylinders controlling the raising and lowering of the stirring needle and stirring sleeve. This invention easily achieves coaxial drive; the two hollow rotary hydraulic cylinders, the stirring needle, and the stirring sleeve are coaxial, thus eliminating the need for a side shaft with bending moment.

[0005] The present invention can be achieved through the following technical solution: a dual hydraulic drive backfill friction stir spot welding device, including an electric spindle and a welding fixture composed of a stirring pin, a stirring sleeve and a clamping sleeve. The device is also provided with a stirring pin drive system and a stirring sleeve drive system for driving the stirring pin and the stirring sleeve to move axially, respectively. The stirring pin drive system, the stirring sleeve drive system and the electric spindle are coaxially arranged and coincide with the rotation center of the welding fixture. The electric spindle is used to drive the stirring pin and the stirring sleeve to rotate. The power source of the stirring pin drive system and the stirring sleeve drive system is a hollow rotary hydraulic cylinder.

[0006] A further technical improvement of the present invention is that: a spindle is provided in the electric spindle, an upper stirring needle shaft is connected to the spindle in the form of a spline, a lower stirring needle shaft is coaxially provided below the upper stirring needle shaft, a stirring needle shaft connecting rod for transmitting torque is provided between the upper stirring needle shaft and the lower stirring needle shaft, and the stirring needle is fixedly installed at the bottom of the lower stirring needle shaft.

[0007] A further technical improvement of the present invention is that a square through groove is provided in the axial direction of the stirring needle shaft connecting rod, and square pins for transmitting torque are provided at both ends of the upper and lower stirring needle shafts. Both square pins cooperate with the square through groove to realize the transmission of torque.

[0008] A further technical improvement of the present invention is that: a rectangular plane structure is provided at the bottom of the lower stirring needle shaft, and a rectangular plane structure is provided at the upper end of the stirring needle. The two rectangular plane structures cooperate with each other to restrict the rotation of the stirring needle relative to the lower stirring needle shaft, and at the same time, the stirring needle and the lower stirring needle shaft are axially fixed by a locking nut.

[0009] A further technical improvement of the present invention is that: the stirring needle drive system is set above the stirring sleeve drive system, and in the stirring needle drive system, the piston rods of the hollow rotary hydraulic cylinder are fixed at both ends to the upper stirring needle shaft and the lower stirring needle shaft.

[0010] A further technical improvement of the present invention is that: in the stirring sleeve drive system, the piston rod of the central hole rotary hydraulic cylinder is provided with and fixed to the stirring sleeve shaft, and the bottom of the stirring sleeve shaft is fixedly connected to the stirring sleeve.

[0011] A further technical improvement of the present invention is that the stirring sleeve is sleeved on the outside of the lower stirring needle shaft, and the two are connected in a spline manner.

[0012] A further technical improvement of the present invention is that: the stirring sleeve is slidably disposed in the lower opening of the clamping sleeve, and the contact surface between the stirring sleeve and the clamping sleeve, and the contact surface between the stirring sleeve and the stirring needle are both set as mirror surfaces with a surface roughness of less than 0.08μm.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. Two hollow rotary hydraulic cylinders are used to control the raising and lowering of the stirring needle and stirring sleeve. The hollow piston rod of the rotary hydraulic cylinder in this equipment can rotate and extend and retract axially simultaneously to control the vertical linear movement of the stirring needle and stirring sleeve. The structure is compact and the operation is reliable. When used to achieve reciprocating motion, a speed reduction device is eliminated, and there is no transmission backlash, resulting in smooth movement. This eliminates the problem of the motor and lead screw being embedded inside the main shaft, leading to a less compact structure and difficulty in achieving coaxial control.

[0015] 2. By coaxially setting the electric spindle, stirring pin drive system and stirring sleeve drive system in the spindle, the stirring sleeve and stirring pin can rotate and move axially during the welding process. The drive source is coaxial with the stirring pin, which solves the problem of bending moment generated by the off-axis drive and ensures the rigidity of the system during the welding process.

[0016] 3. Through the cooperation of dual hydraulic drive and electric spindle, friction stir spot welding is realized. This structure has a wide range of applications and can be used in any friction stir welding equipment such as moving and stationary shaft shoulder friction stir welding, gantry type and robotic arm type. Attached Figure Description

[0017] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0018] Figure 1 This is a cross-sectional view of the overall internal structure of the present invention;

[0019] Figure 2 This is a schematic diagram of a portion of the stirring needle drive system of the present invention;

[0020] Figure 3 This is a schematic diagram of a portion of the stirring sleeve drive system of the present invention.

[0021] In the diagram: 1. Upper stirring needle shaft; 2. Mandrel; 3. Hollow rotary hydraulic cylinder one; 4. Stirring needle shaft connecting rod; 5. Spacer; 6. Locking nut one; 7. Upper bearing cover; 8. Bearing; 9. Lower bearing cover; 10. Lower stirring needle shaft; 11. Hollow rotary hydraulic cylinder two; 12. Stirring sleeve shaft; 13. Locking nut two; 14. Locking nut three; 15. Locking nut four; 16. Pressing sleeve; 17. Stirring sleeve; 18. Outer shell; 19. Stirring needle; 20. Electric spindle. Detailed Implementation

[0022] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0023] Please see Figure 1-3 As shown, a dual hydraulic drive backfill friction stir spot welding device includes an electric spindle 20, a stirring needle drive system, a stirring sleeve drive system, and a welding fixture composed of a stirring needle 19, a stirring sleeve 17, and a clamping sleeve 16.

[0024] A spindle 2 is fixedly installed in the middle of the electric spindle 20. A spline groove is provided on the inner wall of the spindle 2. A spline is provided on the top of the upper stirring needle shaft 1. The spindle 2 is connected to the upper stirring needle shaft 1 through the spline. The spindle 2 and the upper stirring needle shaft 1 can slide relative to each other, but cannot rotate relative to each other. When the electric spindle 20 is energized, the spindle 2 rotates and drives the upper stirring needle shaft 1 to rotate together.

[0025] The electric spindle 20 is fixedly connected to the welding tool by connecting bolts. The stirring needle drive system and the stirring sleeve drive system are set inside the housing 18. The stirring needle drive system and the stirring sleeve drive system are located inside the housing 18 and are used to drive the stirring needle 19 and the stirring sleeve 17 to move axially. The driving method adopted is hydraulic drive.

[0026] The stirring needle drive system includes a hollow rotary hydraulic cylinder 3 as a power source. The upper and lower ends of the piston rod of the hollow rotary hydraulic cylinder 3 are axially fixed with an upper stirring needle shaft 1 and a lower stirring needle shaft 10 by locking nuts 6, respectively. Square pins for transmitting torque are provided at opposite ends of the upper and lower stirring needle shafts 1 and 10. A stirring needle shaft connecting rod 4 is provided between the upper and lower stirring needle shafts 1 and 10. A square through groove is opened in the axial direction of the stirring needle shaft connecting rod 4. The square pins of the upper and lower stirring needle shafts 1 and 10 cooperate with the square through groove to realize the transmission of torque. The piston rod of the hollow rotary hydraulic cylinder 3 is fixed together with the upper stirring needle shaft 1, the lower stirring needle shaft 10 and the stirring needle shaft connecting rod 4. The piston rod of the hollow rotary hydraulic cylinder 3 is driven by a hydraulic station to extend and retract up and down, thereby driving the upper and lower stirring needle shafts 1 and 10 to move up and down.

[0027] A stirring pin 19 is provided at the bottom of the lower stirring pin shaft 10. A rectangular plane structure is provided at the bottom of the lower stirring pin shaft 10, and a rectangular plane structure is provided at the upper end of the stirring pin 19. The rectangular plane is used to restrict the rotation of the stirring pin 19 relative to the lower stirring pin shaft 10. At the same time, the stirring pin 19 and the lower stirring pin shaft 10 are locked and fixed by the locking nut 15, which restricts the axial movement of the stirring pin 19 relative to the lower stirring pin shaft 10.

[0028] The stirring sleeve drive system includes a hollow rotary hydraulic cylinder 11 as a power source. The hollow piston rod of the hollow rotary hydraulic cylinder 11 is equipped with a stirring sleeve shaft 12. The stirring sleeve shaft 12 and the piston rod of the hollow rotary hydraulic cylinder 11 are axially fixed by a locking nut 13. The hydraulic station drives the hydraulic oil to make the piston rod of the hollow rotary hydraulic cylinder 11 extend and retract up and down, thereby driving the stirring sleeve shaft 12 to move up and down.

[0029] The stirring sleeve shaft 12 is sleeved on the outside of the lower stirring needle shaft 10 and is connected in a spline manner. The stirring sleeve shaft 12 and the lower stirring needle shaft 10 can only move relative to each other vertically, and the stirring sleeve shaft 12 and the lower stirring needle shaft 10 rotate synchronously. The bottom of the stirring sleeve shaft 12 is axially fixed to the stirring sleeve 17 by a locking nut 14, which is a spline nut. Therefore, the stirring sleeve shaft 12 can drive the stirring sleeve 17 to rotate synchronously.

[0030] It should be noted that the clamping sleeve 16 is coaxially fixedly installed at the lower part of the outer shell 18 to clamp the workpiece to be welded. The stirring sleeve 17 is slidably installed in the lower opening of the clamping sleeve 16. The stirring sleeve 17 wraps around the lower end of the stirring needle 19 to ensure that it will not bend under stress. The contact surfaces between the stirring sleeve 17 and the clamping sleeve 16, as well as between the stirring sleeve 17 and the stirring needle 19, are all set to mirror surface with a surface roughness of less than 0.08μm.

[0031] A spacer 5 is provided between the hollow rotary hydraulic cylinder 3 and the hollow rotary hydraulic cylinder 11, and the non-moving parts of the two hollow rotary hydraulic cylinders are fixedly connected by the spacer 5. The moving parts of the hollow rotary hydraulic cylinders are separated from the non-moving parts by the bearing 8. The top and bottom of the bearing 8 are limited and fixed by the upper bearing cover 7 and the lower bearing cover 9, respectively.

[0032] When the present invention is in use, the main spindle 20 is energized, so the spindle 2 drives the upper stirring needle shaft 1 to rotate. Since the upper stirring needle shaft 1 and the lower stirring needle shaft 10 are provided with a stirring needle shaft connecting rod 4 and the torque is transmitted through it, the lower stirring needle shaft 10 also rotates, thereby driving the stirring needle 19 fixed at the bottom of the lower stirring needle shaft 10 to rotate.

[0033] The stirring sleeve shaft 12, which is set outside the lower stirring needle shaft 10 by a spline connection, also rotates synchronously with the lower stirring needle shaft 10 when the torque is transmitted by the spline, thereby driving the stirring sleeve 17 fixed at its bottom to rotate.

[0034] Subsequently, the hydraulic station drives two hollow rotary hydraulic cylinders to control the up and down movement of the stirring needle shaft 10 and the stirring sleeve shaft 12, thereby realizing the retraction (downward insertion) of the stirring needle 19 and the downward insertion (retraction) of the stirring sleeve 17, thus completing the welding operation.

[0035] During welding, the clamping sleeve 12 is positioned and clamped onto the workpiece to be welded. The working state of the two motors is coordinated and controlled by the relationship between pressure and displacement. The stirring needle shaft 2 and the stirring sleeve 11 are adjusted for lifting and lowering respectively. Through the cooperation of the two motors and the electric spindle 20, magnetic field controlled stirring friction spot welding is realized, thereby accurately realizing the welding mode of controlling the relationship between pressure and displacement and performing precise welding.

[0036] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A dual hydraulically driven backfill friction stir spot welding device, comprising an electric spindle (20) and a welding fixture composed of a stirring needle (19), a stirring sleeve (17), and a clamping sleeve (16), characterized in that, The equipment is also equipped with a stirring needle drive system and a stirring sleeve drive system for driving the stirring needle (19) and the stirring sleeve (17) to move axially, respectively. The stirring needle drive system, the stirring sleeve drive system and the electric spindle (20) are coaxially arranged and coincide with the rotation center of the welding tool. The electric spindle (20) is used to drive the stirring needle (19) and the stirring sleeve (17) to rotate. The power source of the stirring needle drive system and the stirring sleeve drive system is a hollow rotary hydraulic cylinder. The electric spindle (20) is provided with a spindle (2), and an upper stirring needle shaft (1) is connected to the spindle (2) by a spline. A lower stirring needle shaft (10) is coaxially provided below the upper stirring needle shaft (1). A stirring needle shaft connecting rod (4) for transmitting torque is provided between the upper stirring needle shaft (1) and the lower stirring needle shaft (10). The stirring needle (19) is fixedly installed at the bottom of the lower stirring needle shaft (10). The stirring needle shaft connecting rod (4) has a square through groove in the axial direction. The upper stirring needle shaft (1) and the lower stirring needle shaft (10) are provided with square pins for transmitting torque at their opposite ends. Both square pins are engaged with the square through groove to realize the transmission of torque. In the stirring sleeve drive system, the piston rod of the central hole rotary hydraulic cylinder is equipped with a stirring sleeve shaft (12) and fixed thereto, and the bottom of the stirring sleeve shaft (12) is fixedly connected to the stirring sleeve (17). The stirring sleeve shaft (12) is sleeved on the outside of the lower stirring needle shaft (10), and the two are connected in the form of a spline. The stirring sleeve (17) is slidably disposed in the lower opening of the clamping sleeve (16), and the contact surface between the stirring sleeve (17) and the clamping sleeve (16) and the contact surface between the stirring sleeve (17) and the stirring needle (19) are both set as mirror surfaces with a surface roughness of less than 0.08μm.

2. The dual hydraulic drive backfilling friction stir spot welding equipment according to claim 1, characterized in that, The bottom of the lower stirring needle shaft (10) is provided with a rectangular plane structure, and the upper end of the stirring needle (19) is provided with a rectangular plane structure. The two rectangular plane structures cooperate with each other to restrict the rotation of the stirring needle (19) relative to the lower stirring needle shaft (10). At the same time, the stirring needle (19) and the lower stirring needle shaft (10) are axially fixed by locking nuts.

3. The dual hydraulic drive backfilling friction stir spot welding equipment according to claim 1, characterized in that, The stirring needle drive system is located above the stirring sleeve drive system. In the stirring needle drive system, the piston rods of the hollow rotary hydraulic cylinder are fixed at both ends to the upper stirring needle shaft (1) and the lower stirring needle shaft (10).

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