An automated spot welding machine and a spot welding method thereof

Abstract

The application discloses an automatic spot welding machine, which comprises a workbench base, a linear drive module, a high-precision positioning clamp, a spot welding head and an electrical control box. The linear drive module is horizontally installed on the workbench base, and the high-precision positioning clamp is driven by the linear drive module to make horizontal reciprocating motion. The spot welding head is located directly above the moving track of the clamp, is installed on the electrical control box through a support and can move longitudinally. The electrical control box is internally provided with a controller, a foot switch and a switching power supply, and each component is electrically connected with the controller. The high-precision positioning clamp is used to replace manual tweezers clamping, thereby solving the problems of misalignment and shaking, improving the consistency of welding spots and the stability of welding quality, reducing manual intervention in automatic feeding and welding, lowering labor intensity, avoiding fatigue misoperation, effectively preventing virtual welding, welding through and thermal damage of sensors, improving the yield and component reliability, and making the whole machine compact in structure, simple in operation and applicable to batch efficient manufacturing of micro prestress monitoring components.

Description

Technical Field

[0001] This invention relates to the field of spot welding technology, and more specifically to an automated spot welding machine and its spot welding method. Background Technology

[0002] In large-scale railway transportation hub projects such as the Hangzhou Railway Hub and the Wenzhou South EMU Depot, ultra-long concrete cover slabs widely adopt the slow-bonded prestressed design, which plays a decisive role in structural safety and long-term service performance. To achieve precise control of concrete cracking throughout the entire construction and operation lifecycle, high-precision grating stainless steel sensors need to be deployed in the slow-bonded prestressing tendons to acquire stress and strain data in real time. The grating stainless steel sensor is assembled by welding a metal substrate and the sensor together. Furthermore, this type of monitoring element is extremely miniaturized, with a sensor diameter of only 1mm to 2mm, and the matching metal substrate is typically a thin sheet structure of 30mm to 50mm. Whether such a small sensor and substrate can be accurately connected becomes a key factor restricting the manufacturing quality and efficiency of the monitoring element.

[0003] In current construction techniques, spot welding of miniature sensors to substrates primarily relies on manual operation of portable spot welding machines. Operators must use tweezers to pick up the sensor, align it with the predetermined welding position on the substrate, and then perform manual spot welding. Due to the extremely small size of the workpiece, the manual alignment process is extremely time-consuming and labor-intensive. Prolonged high-intensity work easily leads to eye and hand fatigue for operators, affecting work efficiency and physical health. More importantly, hand tremors are unavoidable during manual welding, making it difficult to ensure the consistency of weld point positions and the stability of welding quality. This easily results in problems such as incomplete welds, burn-through, or sensor damage due to localized overheating, severely restricting product yield and the reliability of monitoring data.

[0004] Although some semi-automatic spot welding equipment exists on the market, most of them are designed for workpieces of conventional size and lack special fixtures for high-precision positioning of such miniaturized monitoring components. When dealing with such micro-sized workpieces, existing equipment generally suffers from technical defects such as insufficient positioning accuracy, poor feeding stability, and difficulty in ensuring welding consistency, resulting in low production efficiency and yield rates that cannot meet the requirements of engineering applications. Summary of the Invention

[0005] In view of the shortcomings of manual welding, such as low efficiency, poor yield, and lack of high-precision special fixtures, the present invention provides an automated spot welding machine that can improve the welding yield by increasing efficiency.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: An automated spot welding machine includes a workbench base, a linear drive module, a high-precision positioning fixture, a spot welding head, and an electrical control box. The linear drive module is horizontally fixed on the workbench base. The high-precision positioning fixture is mounted on the linear drive module and is driven by the linear drive module to perform linear reciprocating motion in the horizontal direction. The spot welding head is located directly above the moving trajectory of the high-precision positioning fixture and is mounted on the electrical control box via a bracket, and the spot welding head performs linear reciprocating motion in the longitudinal direction. The electrical control box also includes a controller, a foot switch, and a switching power supply. The linear drive module, the spot welding head, the foot switch, and the switching power supply are electrically connected to the controller.

[0007] Furthermore, the high-precision positioning fixture body is an insulating substrate, and a substrate positioning groove for accommodating the substrate is machined in the middle of its upper surface along the length direction; in the center of the bottom surface of the substrate positioning groove, a sensor positioning groove is formed along its length direction, and the two ends of the sensor positioning groove extend outside the substrate positioning groove and continue to extend longitudinally along the surface of the insulating substrate to form a through guide channel. The sensor positioning slot is adapted to circular sensors with a diameter of 1-2mm, while the substrate positioning slot is adapted to substrates with a diameter of 30-50mm, ensuring precise alignment between the circular sensor and the substrate before welding. In use, the metal substrate is first placed into the substrate positioning slot, then the sensor is inserted into the sensor positioning slot above the substrate. The sensor's wires are placed in the through-guide channel to prevent accidental contact with the wires later. The insulating substrate is then installed into the linear drive module and moved to the underside of the spot welding head for welding. This structure uses an insulating substrate to avoid current interference. The substrate and sensor are positioned quickly and accurately through nested slots, and the through-channel facilitates sensor insertion. The overall structure is simple, efficient, and significantly improves welding consistency and yield, while reducing manual operation difficulty and the risk of sensor damage.

[0008] Furthermore, the high-precision positioning fixture is symmetrically equipped with two sets of clamping mechanisms near both ends along the length of the substrate positioning groove. Each clamping mechanism includes a pair of limiting studs and a contouring plate. The limiting studs are symmetrically arranged on both sides of the substrate positioning groove, with each limiting stud threaded with a limiting nut. The contouring plate has through holes at both ends that mate with the limiting studs. After the substrate and sensor to be welded are sequentially placed into the substrate positioning groove and sensor positioning groove of the high-precision positioning fixture, the contouring plate is placed on top. The center of the contouring plate contacts the substrate and sensor, while the limiting studs are inserted on both sides. After the center of the contouring plate is clamped, the limiting nuts are screwed in to achieve positioning. Through the cooperation of the contouring plate and the limiting studs and nuts, reliable clamping and precise positioning of small workpieces are achieved, preventing displacement due to vibration or thermal deformation during welding, ensuring consistent weld point positions, and providing simple and highly repeatable operation.

[0009] Furthermore, the contouring pressure plate has an inverted M-shaped structure in the middle to mate with the workpiece to be welded, and connecting plates on both sides to mate with limiting studs. In use, after placing the substrate and sensor into the positioning groove in sequence, the contouring pressure plate is placed with the middle of the inverted M-shape aligned with the top of the workpiece, so that the two concave surfaces of the inverted M-shape structure respectively fit against the two ends of the substrate and avoid the middle sensor. The transition area formed in the middle mates with the sensor, and the connecting plates on both sides naturally fit into the limiting studs. Then, the limiting nuts are tightened to press and fix it. This inverted M-shaped structure can effectively press the two ends of the substrate to ensure overall stability during welding, while avoiding direct pressure on the small sensor in the middle to prevent damage. At the same time, the structure is simple, easy to assemble and disassemble, improves positioning accuracy, and protects sensitive elements.

[0010] Furthermore, the linear drive module is equipped with a set of positioning posts, one of which is cylindrical and the other is polygonal; the insulating substrate has through holes that mate with the positioning posts. In use, the insulating substrate is aligned with the positioning posts on the linear drive module, allowing the through holes on the substrate to fit the cylindrical and polygonal positioning posts respectively. The cylindrical positioning post achieves reference centering, while the polygonal positioning post prevents the substrate from rotating around its axis, ensuring that the fixture is uniquely and accurately positioned above the mounting block. Using the positioning posts for positioning effectively eliminates rotational freedom while ensuring rapid loading and unloading, improving the accuracy and stability of repeated installation between the fixture and the drive module, and preventing welding misalignment. Simultaneously, several insulating substrates, through their cooperation with the positioning posts, allow for rapid replacement of workpieces before and after welding without recalibrating their positions, significantly shortening non-production time and improving equipment utilization and overall production efficiency.

[0011] Furthermore, the linear drive module includes a mounting base, a ball screw, and a stepper motor with an electrical connection controller; the ball screw includes a screw, balls, and a nut with a ball return device or a reverser, the screw is rotatably mounted in the mounting base, and the screw shaft engages with the nut through the balls; the upper surface of the nut is also provided with a mounting block that engages with a high-precision positioning fixture; the output end of the stepper motor is connected to a transmission box, which is located inside the mounting base, and its output end is connected to the screw. In use, a high-precision positioning fixture containing a substrate and sensor, already clamped, is fixed onto the mounting block of the linear drive module. The controller drives a stepper motor according to a preset program. The stepper motor drives a lead screw in the mounting base to rotate through a transmission box. The lead screw and a nut with balls and a return ball mechanism form a precision ball screw pair, converting the rotational motion into the linear motion of the nut, thereby driving the mounting block and fixture to move with high precision to the spot welding station along the set direction. This structure achieves micron-level positioning control through the cooperation of a stepper motor and a ball screw. The transmission box ensures smooth power transmission, good overall rigidity, and high repeatability, effectively ensuring the consistency of the welding position. At the same time, it operates smoothly and responds quickly, adapting to the requirements of automated cycle time.

[0012] Furthermore, the transmission box includes a set of meshing bevel gears, with the vertical bevel gear connected to the output end of the stepper motor. One end of the lead screw passes through another bevel gear inside the transmission box and is rotatably connected to the mounting base, with an interference fit between the lead screw and the bevel gear. In use, after the stepper motor starts, it drives the vertical bevel gear inside the transmission box to rotate. This bevel gear meshes with another horizontal bevel gear, converting the power from the vertical direction to the horizontal direction. One end of the lead screw passes through the horizontal bevel gear and is firmly connected to it through an interference fit, ensuring that the two rotate synchronously without relative slippage. The other end of the lead screw is rotatably connected to the mounting base through a bearing. Driven by the bevel gear, the lead screw rotates stably, and then the rotational motion is precisely converted into linear motion through the ball nut pair, driving the mounting block and fixture to move precisely to the welding station. This structure achieves efficient reversing transmission in a compact spatial layout through bevel gears, while the interference fit between the lead screw and the bevel gear effectively eliminates transmission backlash, significantly improving system rigidity, response accuracy, and repeatability stability.

[0013] Furthermore, the mounting base has linear tracks on both outer sides; the mounting block has grooved wheels on both sides that mate with the linear tracks. In use, the linear tracks on both outer sides of the mounting base and the grooved wheels on both sides of the mounting block form a rolling guide engagement. When the lead screw rotates under the drive of the bevel gear, it drives the ball nut and the mounting block fixed to it to move axially along the lead screw. The grooved wheels roll along the linear tracks, precisely guiding and limiting the movement of the mounting block. The engagement of the grooved wheels and the linear tracks effectively constrains the degree of freedom of the mounting block perpendicular to the direction of movement, preventing it from swaying or shaking. Simultaneously, the rolling contact significantly reduces frictional resistance, ensuring a smooth, stable, and low-wear process.

[0014] The sensor is a miniature tubular grating or magnetic flux sensor, the switching power supply is 24V, and the foot switch serves as the external trigger signal input for a single automatic welding program; the spot welding head adopts the welding structure of an existing electric welding machine. A spot welding method using an automated spot welding machine includes the following steps: S1. The operator first places the metal substrate and the sensor into the high-precision positioning fixture in sequence to make the sensor and the metal substrate fit tightly together. Then the high-precision positioning fixture is installed on the linear drive module. S2. Turn on the machine's power switch. After the operator steps on the foot switch, the electrical control box receives the signal and controls the linear drive module to start, which drives the high-precision positioning fixture to move along the linear track and accurately transport the substrate and sensor to be welded area to the welding station directly below the spot welding head. S3. After the metal substrate and the sensor to be welded area are in place, the spot welding head automatically presses down vertically, the welding needle contacts the workpiece and discharges, and the resistance spot welding of the sensor and the metal substrate is completed. S4. After welding is completed, the spot welding head automatically lifts up, and the linear drive module drives the high-precision positioning fixture back to the initial position. The operator then takes out the welded workpiece, thus completing a full welding cycle.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. This invention solves the problems of inaccurate positioning and easy shaking when using manual tweezers by using a high-precision positioning fixture, significantly improving the consistency of weld point positions and the stability of welding quality; automated feeding and welding reduce manual intervention, greatly reducing the labor intensity of operators and avoiding misoperation due to fatigue; it effectively prevents defects such as incomplete welding, burn-through, and sensor thermal damage, improving product yield and the reliability of monitoring elements; at the same time, the whole device has a compact structure and is easy to operate, making it suitable for the mass production and efficient manufacturing of miniaturized prestressed monitoring elements, meeting the large-scale demand for high-precision sensing elements in large-scale railway hub projects.

[0016] 2. This invention achieves rapid clamping, precise alignment, and reliable pressing of micro sensors and substrates through the collaborative design of a high-precision positioning fixture and a linear drive module. Combined with a high-rigidity, micron-level positioning drive system consisting of a ball screw, stepper motor, and bevel gear transmission box, and a stable guiding mechanism composed of linear tracks and grooved wheels, it effectively ensures the consistency and repeatability of the welding position. Simultaneously, the insulating substrate and through-type guide channel avoid electrical interference and protect the wires, while the inverted M-shaped contour plate avoids sensitive sensors while pressing the substrate, significantly improving welding yield, operational efficiency, and equipment automation level.

[0017] 3. This invention specifically designs a high-precision contour positioning groove made of insulating material for micro gratings or magnetic flux sensors in the 1mm to 2mm range, eliminating random errors caused by manual clamping and alignment. The center of the sensor is forced to coincide with the center line of the substrate, ensuring that the finished sensor achieves an ultra-high monitoring accuracy of 1% from a manufacturing hardware perspective. Through a closed-loop conveying system composed of a stepper motor and a ball screw, the equipment can deliver the workpiece under the spot welding head with extremely high repeatability. The welding head applies constant pressure and discharges quantitatively, ensuring that the penetration depth and bonding force of each weld point are completely consistent, eliminating incomplete welds and over-welding, and improving the product yield.

[0018] 4. With this invention, operators only need to perform simple loading and unloading operations at a location away from the welding area, significantly reducing eye fatigue caused by high visual concentration and effectively avoiding direct damage to the eyes and skin from spot welding arc light. Based on linear tracks and stable stepping drive, it not only significantly shortens the welding cycle of a single sensor but also ensures stable and reliable operation. The workpiece will not shift due to vibration during movement, greatly improving the productivity per unit time. The produced sensing components are small in size and firmly integrated, perfectly fitting onto the loosely bonded prestressed steel strands. This provides solid underlying hardware data acquisition support for the fine control of cracks in the concrete cover plates of ultra-long EMU trains and the coordinated analysis of data and simulation, possessing extremely high engineering practical value. Attached Figure Description

[0019] Figure 1 This is a top-view schematic diagram of the overall structure of an automated spot welding machine according to the present invention.

[0020] Figure 2 This is a schematic diagram of the overall structure of an automated spot welding machine according to the present invention from the perspective of the main view.

[0021] Figure 3 This is a schematic diagram illustrating the connection between the mounting base and the ball screw of an automated spot welding machine according to the present invention.

[0022] Attached image labels: Workbench base-1, linear rail-11, grooved wheel-12, linear drive module-2, positioning column-21, mounting base-22, ball screw-23, stepper motor-24, transmission box-25, high-precision positioning fixture-3, substrate positioning groove-31, sensor positioning groove-32, spot welding head-4, electrical control box-5, clamping mechanism-6, limit stud-61, contour pressure plate-62, limit nut-63. Detailed Implementation

[0023] The invention will be further described below with reference to the accompanying drawings.

[0024] Example 1: An automated spot welding machine includes a workbench base 1, a linear drive module 2, a high-precision positioning fixture 3, a spot welding head 4, and an electrical control box 5. The linear drive module 2 is horizontally fixed on the workbench base 1. The high-precision positioning fixture 3 is mounted on the linear drive module 2 and is driven by the linear drive module 2 to perform linear reciprocating motion in the horizontal direction. The spot welding head 4 is located directly above the moving trajectory of the high-precision positioning fixture 3 and is mounted on the electrical control box 5 via a bracket. The spot welding head 4 also performs linear reciprocating motion in the longitudinal direction. The electrical control box 5 further includes a controller, a foot switch, and a switching power supply. The linear drive module 2, the spot welding head 4, the foot switch, and the switching power supply are electrically connected to the controller.

[0025] The sensor is a miniature tubular grating or magnetic flux sensor, the switching power supply is 24V, and the foot switch is used as the external trigger signal input for a single automatic welding program; the spot welding head 4 adopts the welding structure of an existing electric welding machine. The spot welding method includes the following steps: S1. The operator first places the metal substrate and the sensor into the high-precision positioning fixture 3 in sequence to make the sensor and the metal substrate fit tightly together. Then the high-precision positioning fixture 3 is installed on the linear drive module 2. S2. Turn on the machine's power switch. After the operator steps on the foot switch, the electrical control box 5 receives the signal and controls the linear drive module 2 to start, driving the high-precision positioning fixture 3 to move along the linear track 11, accurately conveying the substrate and sensor to be welded area to the welding station directly below the spot welding head 4. S3. After the metal substrate and the sensor to be welded area are in place, the spot welding head 4 automatically presses down vertically, the welding needle contacts the workpiece and discharges, and the resistance spot welding of the sensor and the metal substrate is completed. S4. After welding is completed, the spot welding head 4 automatically lifts up, and the linear drive module 2 drives the high-precision positioning fixture 3 back to the initial position. The operator takes out the welded workpiece, thus completing a complete welding cycle.

[0026] The high-precision positioning fixture 3 is a substrate made of insulating material. A substrate positioning groove 31 for accommodating a substrate is machined in the middle of its upper surface along the length direction. A sensor positioning groove 32 is formed in the center of the bottom surface of the substrate positioning groove 31 along its length direction. The two ends of the sensor positioning groove 32 extend to the outside of the substrate positioning groove 31 and continue to extend longitudinally along the surface of the insulating substrate to form a through guide channel. The sensor positioning slot 32 is adapted to circular sensors with a diameter of 1-2mm, and the substrate positioning slot 31 is adapted to substrates with a size of 30-50mm, ensuring precise alignment between the circular sensor and the substrate before welding. In use, the metal substrate is first placed into the substrate positioning slot 31, and then the sensor is inserted into the sensor positioning slot 32 above the substrate. The sensor wires are placed in the through guide channel to avoid accidental contact with the wires later. Then, the insulating substrate is installed into the linear drive module 2 and moved to the spot welding head 4 for welding. This structure uses an insulating substrate to avoid current interference. The substrate and sensor are quickly and accurately positioned through the nested slots, and the through channel facilitates sensor installation. The overall structure is simple and efficient, significantly improving welding consistency and yield, while reducing manual operation difficulty and the risk of sensor damage.

[0027] The linear drive module 2 includes a mounting base 22, a ball screw 23, and a stepper motor 24 electrically connected to the controller. The ball screw 23 includes a screw, balls, and a nut with a ball return mechanism or a reverser. The screw is rotatably mounted in the mounting base 22, and the screw shaft engages with the nut via the balls. The upper surface of the nut is also provided with a mounting block that engages with a high-precision positioning fixture 3. The output end of the stepper motor 24 is connected to a transmission box 25, which is located inside the mounting base 22, and its output end is connected to the screw. In use, the high-precision positioning fixture 3, which contains the substrate and sensor and is already clamped, is fixed on the mounting block of the linear drive module 2. The controller drives the stepper motor 24 to operate according to the preset program. The stepper motor 24 drives the lead screw in the mounting base 22 to rotate through the transmission box 25. The lead screw and the nut with ball bearings and ball return form a precision ball screw pair 23, which converts the rotational motion into the linear motion of the nut, thereby driving the mounting block and fixture to move with high precision to the spot welding station along the set direction. This structure achieves micron-level positioning control through the cooperation of the stepper motor 24 and the ball screw 23. The transmission box 25 ensures smooth power transmission, good overall rigidity, high repeatability, and effectively ensures the consistency of the welding position. At the same time, it runs smoothly and responds quickly, which can meet the requirements of automation cycle.

[0028] Example 3: The difference from Example 2 is that the high-precision positioning fixture 3 is also symmetrically provided with two sets of clamping mechanisms 6 near both ends along the length of the substrate positioning groove 31; the clamping mechanism 6 includes a pair of limiting studs 61 and a contoured pressure plate 62. The limiting studs 61 are symmetrically arranged on both sides of the substrate positioning groove 31, and each limiting stud 61 is threaded with a limiting nut 63; the contoured pressure plate 62 is provided with through holes at both ends that cooperate with the limiting studs 61. The substrate and sensor to be welded are sequentially placed into the substrate positioning slot 31 and sensor positioning slot 32 of the high-precision positioning fixture 3, and then the contour plate 62 is placed on top. The middle of the contour plate 62 contacts the substrate and sensor, and the limiting studs 61 are inserted on both sides. After the middle of the contour plate 62 is pressed, the limiting nut 63 is screwed in to achieve the limiting. Through the cooperation of the contour plate 62, the limiting studs 61, and the limiting nut 63, reliable clamping and precise limiting of the small workpiece are achieved, preventing displacement caused by vibration or thermal deformation during the welding process, ensuring that the weld point position is consistent, and the operation is simple and highly repeatable.

[0029] The contouring pressure plate 62 has an inverted M-shaped structure in the middle to fit the workpiece to be welded, and connecting plates on both sides to fit the limiting studs 61. In use, after the substrate and sensor are placed into the positioning groove in sequence, the contouring pressure plate 62 is placed with the middle of the inverted M-shape aligned with the top of the workpiece, so that the two concave surfaces of the inverted M-shape fit against the two ends of the substrate and avoid the middle sensor. The transition area formed in the middle fits with the sensor. The connecting plates on both sides naturally fit into the limiting studs 61, and then the limiting nuts 63 are tightened to press and fix it. This inverted M-shaped structure can effectively press the two ends of the substrate to ensure overall stability during welding, while avoiding direct pressure on the small sensor in the middle to prevent damage. At the same time, the structure is simple, easy to assemble and disassemble, improves positioning accuracy, and protects sensitive elements.

[0030] The linear drive module 2 is equipped with a set of positioning posts 21, one of which is cylindrical and the other is polygonal. The insulating substrate has through holes that mate with the positioning posts 21. In use, the insulating substrate is aligned with the positioning posts 21 on the linear drive module 2, so that the through holes on the substrate fit the cylindrical and polygonal positioning posts 21 respectively. The cylindrical positioning post 21 achieves reference centering, while the polygonal positioning post 21 prevents the substrate from rotating around the axis, ensuring that the fixture is uniquely and accurately positioned on the mounting block. Using the positioning posts 21 for positioning, rotational degrees of freedom are effectively eliminated while ensuring quick loading and unloading, improving the repeatability and stability of the fixture and drive module, and avoiding welding offset due to misalignment. At the same time, several insulating substrates can be used in conjunction with the positioning posts 21 to achieve quick replacement of workpieces before and after welding without recalibrating the position, significantly shortening non-production time and improving equipment utilization and overall production efficiency.

[0031] Example 4: Unlike Example 3, the transmission box 25 includes a set of meshing bevel gears. The vertical bevel gear is connected to the output end of the stepper motor 24. One end of the lead screw passes through another bevel gear inside the transmission box 25 and is rotatably connected to the mounting base 22, with an interference fit between the lead screw and the bevel gear. In use, after the stepper motor 24 starts, it drives the vertical bevel gear inside the transmission box 25 to rotate. This bevel gear meshes with another horizontal bevel gear, converting the power from the vertical direction to the horizontal direction. One end of the lead screw passes through the horizontal bevel gear and is firmly connected to it through an interference fit, ensuring synchronous rotation without relative slippage. The other end of the lead screw is rotatably connected to the mounting base 22 through a bearing. Driven by the bevel gear, the lead screw rotates stably, and then the rotational motion is precisely converted into linear motion through the ball bearing nut pair, driving the mounting block and fixture to move precisely to the welding station. This structure achieves efficient reversing transmission in a compact spatial layout through bevel gears, while the interference fit between the lead screw and the bevel gear effectively eliminates transmission backlash, significantly improving system rigidity, response accuracy, and repeatability stability.

[0032] The mounting base 22 has linear tracks 11 on both outer sides; the mounting block has grooved wheels 12 on both sides that cooperate with the linear tracks 11. In use, the linear tracks 11 on both outer sides of the mounting base 22 and the grooved wheels 12 on both sides of the mounting block form a rolling guide engagement. When the lead screw rotates under the drive of the bevel gear, it drives the ball nut and the mounting block fixed to it to move along the axial direction of the lead screw. The grooved wheels 12 roll along the linear tracks 11, providing precise guidance and limiting for the movement of the mounting block. The engagement of the grooved wheels 12 and the linear tracks 11 effectively constrains the degree of freedom of the mounting block in the direction perpendicular to the movement, preventing it from swaying or shaking. At the same time, the rolling contact method significantly reduces frictional resistance, ensuring a smooth and stable movement with low wear.

[0033] Numerous specific details are set forth in this specification. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. An automated spot welding machine, characterized in that: The device includes a workbench base (1), a linear drive module (2), a high-precision positioning fixture (3), a spot welding head (4), and an electrical control box (5). The linear drive module (2) is horizontally fixed on the workbench base (1). The high-precision positioning fixture (3) is mounted on the linear drive module (2) and is driven by the linear drive module (2) to make linear reciprocating motion in the horizontal direction. The spot welding head (4) is located directly above the moving trajectory of the high-precision positioning fixture (3) and is mounted on the electrical control box (5) by a bracket. The spot welding head (4) makes linear reciprocating motion in the longitudinal direction. The electrical control box (5) also includes a controller, a foot switch, and a switching power supply. The linear drive module (2), the spot welding head (4), the foot switch, and the switching power supply are electrically connected to the controller.

2. The automated spot welding machine as described in claim 1, characterized in that: The high-precision positioning fixture (3) is a substrate made of insulating material. A substrate positioning groove (31) for accommodating the substrate is machined in the middle of its upper surface along the length direction. A sensor positioning groove (32) is opened in the center of the bottom surface of the substrate positioning groove (31) along its length direction. The two ends of the sensor positioning groove (32) extend to the outside of the substrate positioning groove (31) and continue to extend longitudinally along the surface of the insulating substrate to form a through guide channel.

3. An automated spot welding machine as described in claim 2, characterized in that: The high-precision positioning fixture (3) is also provided with two sets of clamping mechanisms (6) symmetrically arranged near both ends along the length direction of the substrate positioning groove (31); the clamping mechanism (6) includes a pair of limiting studs (61) and a contour plate (62). The limiting studs (61) are symmetrically arranged on both sides of the substrate positioning groove (31), and each limiting stud (61) is threaded with a limiting nut (63); the contour plate (62) is provided with through holes at both ends that cooperate with the limiting studs (61).

4. An automated spot welding machine as described in claim 2, characterized in that: The contour plate (62) has an inverted M-shaped structure in the middle that matches the workpiece to be welded, and connecting plates on both sides that match the limiting studs (61).

5. An automated spot welding machine as described in any one of claims 2-4, characterized in that: The linear drive module (2) is provided with a set of positioning posts (21), one of which is cylindrical and the other is polygonal; the insulating substrate is provided with through holes that cooperate with the positioning posts (21).

6. An automated spot welding machine as described in claim 1, characterized in that: The linear drive module (2) includes a mounting base (22), a ball screw (23), and a stepper motor (24) electrically connected to the controller. The ball screw (23) includes a screw, balls, and a nut with a return ball or a reverser. The screw is rotatably mounted in the mounting base (22), and the screw shaft engages with the nut through the balls. The upper surface of the nut is also provided with a mounting block that engages with a high-precision positioning fixture (3). The output end of the stepper motor (24) is connected to a transmission box (25), which is located inside the mounting base (22), and its output end is connected to the screw.

7. An automated spot welding machine as described in claim 6, characterized in that: The transmission box (25) includes a set of meshing bevel gears, wherein the vertical bevel gear is connected to the output end of the stepper motor (24); one end of the lead screw passes through another bevel gear inside the transmission box (25) and is rotatably connected to the mounting base (22), and the lead screw and the bevel gear are interference fit.

8. An automated spot welding machine as described in claim 6, characterized in that: The mounting base (22) has linear rails (11) on its two outer sides; the mounting block has grooved wheels (12) on both sides that cooperate with the linear rails (11).

9. The spot welding method of an automated spot welding machine according to claim 1, comprising the following steps: S1. The operator first places the metal substrate and the sensor into the high-precision positioning fixture (3) in sequence, so that the sensor and the metal substrate are tightly attached. Then the high-precision positioning fixture (3) is installed on the linear drive module (2). S2. Turn on the machine's power switch. After the operator steps on the foot switch, the electrical control box (5) receives the signal and controls the linear drive module (2) to start, driving the high-precision positioning fixture (3) to move along the linear track (11) and accurately transport the substrate and sensor to be welded area to the welding station directly below the spot welding head (4). S3. After the metal substrate and the sensor are in place, the spot welding head (4) automatically presses down vertically, the welding needle contacts the workpiece and discharges, and the resistance spot welding of the sensor and the metal substrate is completed. S4. After welding is completed, the spot welding head (4) is automatically lifted, and the linear drive module (2) drives the high-precision positioning fixture (3) back to the initial position. The operator takes out the welded workpiece, thus completing a complete welding cycle.

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