A nut projection welding anti-weld deviation system

Abstract

This utility model discloses a nut projection welding anti-weld deviation system, belonging to the field of nut projection welding technology. The system is installed on a nut seat welding machine and includes a support plate, a magnetic column, and an insulating plate. The support plate is located below the lower electrode arm of the nut seat welding machine and has a horizontal upper support surface. The magnetic column is an electromagnet structure, connected to a magnetic power supply module that powers its coil. The magnetic column is vertically fixed to the support surface of the support plate, and its top has a horizontal upper magnetic attraction surface. The insulating plate is horizontally disposed on the upper magnetic attraction surface of the magnetic column, and has a notch that exposes a positioning pin on the lower electrode arm, with the positioning pin extending upwards beyond the insulating plate.

Description

Technical Field

[0001] This utility model relates to the field of nut projection welding technology, and in particular to a nut projection welding anti-welding deviation system. Background Technology

[0002] Nut projection welding is an important form of resistance welding. Its basic principle is to pre-fabricate projections on the nut, bringing them into contact with the surface of a metal sheet. When electricity is applied, the contact resistance generates localized high temperatures, melting the projections and surrounding material, thus achieving a reliable connection between the nut and the sheet metal. This process offers significant advantages such as high welding efficiency, good connection strength, and ease of automation, making it widely used in automotive manufacturing, home appliance production, and metal structure assembly, especially playing a crucial role in connecting automotive bodies, chassis, and various support components.

[0003] In a typical projection welding process, the plate to be welded is first placed on the lower electrode arm of the welding machine, so that the pre-drilled hole on the plate fits into the locating pin of the lower electrode. Then, the projection nut is placed on the locating pin, and the guiding action of the locating pin initially ensures the coaxiality of the nut and the bottom hole of the plate. Next, the equipment is started, the upper electrode arm moves downward and presses the nut and plate together, and a strong current is simultaneously applied between the two electrodes. When the current flows through the contact area of ​​the projection, it generates concentrated resistance heat, causing the projection and a localized area of ​​the plate to rapidly melt and form a weld nugget. After cooling under electrode pressure, a strong metallurgical bond is formed, completing the weld.

[0004] However, in actual production, this process still faces a series of problems affecting welding quality and consistency. First, the sheet metal may not be completely flat when placed, or uneven force during electrode pressing may cause micro-deformation, disrupting the initial alignment between the nut and the bottom hole. Second, under welding pressure, if the sheet metal clamps are insufficiently constrained or the locating pins are worn, the sheet metal is prone to slippage or displacement, further exacerbating the loss of alignment accuracy. Furthermore, human error cannot be ignored. For example, if operators remove the material before the welding cycle is fully completed or the electrode has fully returned to its original position, it will interfere with the stability of the welding position. These problems combined can easily lead to coaxiality deviation between the nut's internal thread hole and the sheet metal's bottom hole after welding. In severe cases, this can even result in misaligned or skewed welding, causing the nut's thread hole to be obstructed or partially blocked, seriously affecting the smooth insertion and tightening of subsequent bolts, reducing assembly efficiency and connection reliability.

[0005] Existing patent documents mostly provide solutions for modifying sheet metal and part structures. For example, Chinese utility model patent CN205663727U discloses a structure to prevent misalignment between a projection weld nut and a sheet metal hole. Specifically, it discloses that "this utility model relates to a structure to prevent misalignment between a projection weld nut and a sheet metal hole, including a sheet metal with a through hole and a projection weld nut; the projection weld nut is fixed to the sheet metal by welding; the internal thread hole of the projection weld nut is opposite to the through hole; a groove structure is provided on each side of the surface of the projection weld nut that contacts the sheet metal; the bottom of the projection weld nut between two adjacent groove structures..." A raised portion is formed on the surface of the sheet metal; a groove is provided around the through hole, opposite to the raised portion; the groove communicates with the through hole; the raised portion is inserted into the groove. This application, through the groove structure of the through hole on the sheet metal and the groove structure of the projection weld nut, creates a raised portion on the bottom surface of the projection weld nut. When welding the projection weld nut to the sheet metal, the raised portion is first inserted into the groove, thus fixing the projection weld nut and preventing misalignment. While this structure theoretically improves alignment, its implementation relies on specific modifications to the structures of both the nut and the sheet metal, increasing the complexity of the part design and introducing new challenges in the manufacturing process. Specifically, machining a groove on the sheet metal that precisely matches the raised portion requires higher-precision stamping dies and more complex punching processes, which significantly increases production costs and potentially adversely affects the flatness of the sheet metal. Furthermore, this structural change may lead to stress concentration, affecting the fatigue performance of the weld joint.

[0006] Therefore, in an industrial context that emphasizes production efficiency and cost control, there is an urgent need for a new solution that can effectively guarantee welding alignment accuracy and reliability without changing the basic structure of the nut and plate or requiring complex additional processes, so as to meet the actual needs of modern large-scale automated production. Utility Model Content

[0007] The technical problem to be solved by this utility model is to provide a nut projection welding anti-welding deviation system, which can effectively ensure the welding alignment accuracy and reliability.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: A nut projection welding anti-weld deviation system, installed on a nut seat welding machine, includes: A support plate is located below the lower electrode arm of the nut seat welding machine, and the support plate has a horizontal upper support surface; A magnetic column, an electromagnet structure, is connected to a magnetic power supply module that powers its coil. The magnetic column is vertically fixed to the support surface of a support plate, and its top has a horizontal upper magnetic surface. An insulating plate is horizontally disposed on the upper magnetic surface of the magnetic column. The insulating plate has a notch that exposes the positioning pin on the lower electrode arm, and the positioning pin extends upward beyond the insulating plate.

[0009] A further technical solution is that the magnetic suction column has multiple magnetic suction columns, which are evenly distributed circumferentially around the axis of the positioning pin, and the upper magnetic suction surfaces of the multiple magnetic suction columns are coplanar.

[0010] A further technical solution is that the insulating plate is made of a transparent material.

[0011] A further technical solution is that the insulating plate is fixed to the magnetic column by an adhesive.

[0012] A further technical solution is that the notch is circular in shape, the notch is coaxially arranged with the lower electrode arm, and the inner diameter of the notch is larger than the diameter of the lower electrode arm.

[0013] A further technical solution includes: A proximity sensor is located below an insulating plate; and The controller has its signal input terminal connected to the proximity sensor and the welding start button of the nut seat welding machine, and its control output terminal connected to the actuator of the nut seat welding machine.

[0014] A further technical solution is that the proximity sensor has two components, and the positioning pins on the lower electrode arm of the two proximity sensors are arranged symmetrically at the center.

[0015] A further technical solution is that the control output terminal of the controller is also connected to the magnetic power supply module of the magnetic column.

[0016] A further technical solution includes a level, which is fixed to the edge of the lower surface of the insulating board.

[0017] A further technical solution is that the level has two parts, and the two levels are respectively fixed on two mutually perpendicular sides of the insulating plate.

[0018] The beneficial effects of adopting the above technical solution are as follows: In nut projection welding, the plate to be welded is first placed stably on an insulating plate. After the pre-drilled bottom hole is precisely fitted into the positioning pin of the lower electrode, the system controls the magnetic column to be energized and generate a stable electromagnetic attraction force. This electromagnetic attraction force can firmly attract and fix the plate to the surface of the insulating plate, effectively resisting machine vibration, electrode pressure impact during welding, and preventing plate displacement caused by operator error (such as premature removal of the part before the welding cycle is over). This prevents problems such as misalignment or non-concentricity between the nut's internal thread hole and the plate's bottom hole, thus fundamentally avoiding the risk of nut welding misalignment.

[0019] This anti-deflection system for projection welding of nuts uses magnetic attraction for fixation, effectively avoiding the drawbacks of uneven force during electrode pressing in traditional processes, which can damage the initial alignment of the sheet metal. Simultaneously, the high-temperature insulation properties of the insulating plate precisely guide the welding current to flow concentratedly through the contact area between the nut projection and the sheet metal, ensuring that the current distribution meets welding process requirements and preventing current shunting from affecting the quality of the weld nugget formation. Through the synergistic effect of these two aspects, the system significantly improves the coaxiality of the nut and the bottom hole of the sheet metal after welding, providing a solid guarantee for the smoothness and reliability of subsequent bolt assembly. Attached Figure Description

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0021] Figure 1 This is a schematic diagram of the structure of this utility model. Detailed Implementation

[0022] 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.

[0023] In the description of this utility model, unless otherwise stated, the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0024] like Figure 1 As shown, a nut projection welding anti-welding deviation system is installed on a nut seat welding machine. It can solve the problem of initial alignment failure caused by uneven placement of the plate and uneven pressure of the electrode, and can improve the positioning stability of the plate during the welding process.

[0025] Example 1 The anti-welding deviation system for nut projection welding includes a support plate 1, a magnetic column 2, and an insulating plate 3.

[0026] The support plate 1 is located below the lower electrode arm 101 of the nut seat welding machine, and the support plate 1 has a horizontal upper support surface. The support plate 1 is made of steel plate, and its horizontal upper support surface can be milled to ensure good flatness. The support plate 1 is fixed to the column of the nut seat welding machine by bolts or welding, forming a rigid connection with the machine body, providing a stable installation foundation for the entire anti-welding deviation system and avoiding the impact of positioning accuracy due to the shaking of the support structure.

[0027] The magnetic column 2 is an electromagnet structure, and a magnetic power supply module that supplies power to its coil is connected to the magnetic column 2. Preferably, an overcurrent protection function can be set on the magnetic power supply module to prevent the coil from burning out due to excessive current. The magnetic column 2 is vertically fixed to the support surface of the support plate 1 by welding or other methods. The top of the magnetic column 2 has a horizontal upper magnetic surface, which is ground to have good flatness (the flatness requirement of the upper magnetic surface is <1mm).

[0028] The insulating plate 3 is horizontally positioned on the upper magnetic surface of the magnetic column 2. The insulating properties of the insulating plate 3 prevent contact between the plate and other conductive components such as the electromagnet or the welding machine itself, avoiding current shunting and resulting in incomplete soldering during nut welding. The insulating plate 3 and the magnetic column 2 can be fixed together using adhesive. The adhesive needs to be high-temperature resistant, such as epoxy adhesive, which can withstand temperatures up to 180°C after curing and possesses good insulation properties, without affecting the electrical characteristics of the system. The adhesive fixing of the insulating plate 3 and the magnetic column 2 ensures that the working surface of the insulating plate 3 remains intact and flat, guaranteeing a good fit between the plate and the insulating plate 3. This also reduces the number of assembly parts, improves assembly efficiency, and lowers subsequent maintenance costs.

[0029] The insulating plate 3 has a notch 31 that exposes the positioning pin on the lower electrode arm 101, with the positioning pin extending upward beyond the insulating plate 3. Preferably, the notch 31 is circular, matching the shape of the positioning pin and the lower electrode arm 101 to minimize its influence on the guiding function of the positioning pin. The notch 31 is coaxially arranged with the lower electrode arm 101, and the lower electrode arm 101 is coaxially arranged with the positioning pin; the inner diameter of the notch 31 is larger than the diameter of the lower electrode arm 101.

[0030] After assembly, the upper end face of the lower electrode arm 101 should be flush with the upper surface of the insulating plate 3, so that the plate to be welded can simultaneously form surface contact with the insulating plate 3 and the lower electrode arm 101, further improving the support stability of the plate. The upper end face of the lower electrode arm 101 may also be slightly lower than the upper surface of the insulating plate 3, but the height difference should be controlled within 3mm.

[0031] In the projection welding of nuts, the plate to be welded is first placed stably on the insulating plate 3. After the pre-drilled bottom hole is precisely fitted into the positioning pin of the lower electrode, the system controls the magnetic column to be energized and generate a stable electromagnetic attraction force. This electromagnetic attraction force can firmly attract and fix the plate to the surface of the insulating plate 3, effectively resisting machine vibration and electrode pressure impact during welding, and preventing plate displacement caused by operator misoperation (such as removing the part before the welding cycle is over). This prevents problems such as misalignment or non-concentricity between the internal thread hole of the nut and the bottom hole of the plate, thus avoiding the risk of nut welding misalignment at the source.

[0032] This anti-weld-off-center system for projection welding of nuts uses magnetic attraction for fixation, effectively avoiding the drawbacks of uneven force during electrode pressing that can damage the initial alignment of the sheet metal in traditional processes. Simultaneously, the high-temperature resistant insulation properties of the insulating plate 3 precisely guide the welding current to flow concentratedly through the contact area between the nut projection and the sheet metal, ensuring that the current distribution meets welding process requirements and preventing current shunting from affecting the quality of the weld nugget formation. Through the synergistic effect of these two aspects, the system significantly improves the coaxiality of the nut and the bottom hole of the sheet metal after welding, providing a solid guarantee for the smoothness and reliability of subsequent bolt assembly.

[0033] Example 2 The magnetic suction column 2 is a plurality of such columns, which are evenly distributed circumferentially around the axis of the positioning pin, and the upper magnetic suction surfaces of the plurality of magnetic suction columns 2 are coplanar.

[0034] Preferably, four magnetic posts 2 are provided, which can ensure sufficient adsorption force while avoiding structural complexity caused by too many magnetic posts 2. The four magnetic posts 2 are evenly distributed circumferentially around the axis of the positioning pin on the lower electrode arm 101, and the central angle between two adjacent magnetic posts 2 is 90°. This symmetrical distribution allows the adsorption force on the board to be evenly transmitted to each area, preventing the board from warping due to uneven force.

[0035] After the plate to be welded is placed, multiple magnetic columns 2 are simultaneously energized to generate attraction. Under the action of uniform attraction, the plate adheres tightly to the surface of the insulating plate 3. Even if the plate itself has slight unevenness, the uniform attraction can gradually make it flat. At the same time, the circumferentially distributed structure forms a ring constraint on the plate, effectively limiting the tendency of the plate to slide in the horizontal direction, further improving the alignment accuracy of the nut and the bottom hole. It is especially suitable for thin automotive body plates, solving the problem of welding deviation caused by the easy deformation of thin plates.

[0036] Example 3 The insulating plate 3 is made of a transparent material, enabling visual monitoring of the welding area. Preferably, the insulating plate 3 is made of transparent polycarbonate (PC) material, which not only has excellent insulation and light transmission properties, but also good high temperature resistance, capable of withstanding instantaneous high temperatures above 200°C, fully meeting the temperature environment requirements during the nut projection welding process.

[0037] In actual operation, operators can clearly observe the placement of the sheet material to be welded, the alignment of the nut and the bottom hole, and the formation of the weld nugget during the welding process through the transparent insulating plate 3. If the sheet material is found to be misplaced or the nut is not properly aligned, adjustments can be made in time to avoid unqualified welds. At the same time, the transparent insulating plate 3 can also effectively assist operators in judging whether the welding cycle is completed, preventing the stability of the welding position from being compromised due to premature material removal.

[0038] Example 4 The anti-weld-off system for nut projection welding also includes proximity sensor 4 and controller.

[0039] The proximity sensor 4 is located below the insulating plate 3 with its sensing surface facing upwards, and is used to detect whether a piece of material to be welded is placed on the insulating plate 3. Specifically, the proximity sensor 4 can be fixed to one side of the lower electrode arm 101 and positioned near the notch 31. The signal input terminal of the controller is connected to the proximity sensor 4 and the welding start button of the nut seat welding machine, and the control output terminal of the controller is connected to the actuator of the nut seat welding machine, which includes an upper electrode drive cylinder and an electrode return mechanism.

[0040] During operation, when the operator places the plate on the insulating plate 3, the plate will block the sensing surface of the proximity sensor 4. The proximity sensor 4 sends a "position" signal to the controller. At this time, the operator presses the welding start button. After the controller receives the two signals, it will send an action command to the actuator to control the upper electrode arm 102 to press down and start the welding process.

[0041] Example 5 The proximity sensor 4 has two sensors, and the positioning pins on the lower electrode arm 101 of the two proximity sensors 4 are arranged symmetrically to ensure that the placement state of the plate in two symmetrical directions can be detected respectively.

[0042] When receiving detection signals, the controller employs a "dual-signal confirmation" logic. Only when both proximity sensors 4 simultaneously detect the plate and send a "positioned" signal will the controller determine that the plate is properly placed and allow the welding process to begin. If only one sensor detects a signal, or if neither sensor detects a signal, the controller determines that the plate is not level and prohibits welding. This symmetrically arranged dual-sensor structure can effectively identify improper placement conditions such as warping of the plate, avoiding misjudgments caused by blind spots of a single sensor, and further improving the reliability of positioning detection.

[0043] Example 6 The controller's control output terminal is also connected to the magnetic power supply module of the magnetic column 2.

[0044] During operation, when the operator places the plate on the insulating plate 3, the plate will block the sensing surface of the proximity sensor 4, and the proximity sensor 4 will send a "position" signal to the controller. At this time, the operator presses the welding start button. After receiving the two signals, the controller sends a power supply command to the magnetic power supply module to energize the magnetic column 2 and attract the plate. On the other hand, it sends an action command to the actuator to control the upper electrode arm 102 to press down and start the welding process.

[0045] After welding is completed, the controller first controls the electrodes to return to their original position. Once the electrodes are fully returned, it delays for a few seconds before cutting off power to the magnetic power supply module. At this point, the operator can easily remove the welded workpiece. This delayed power-off design ensures that the operator can only remove the workpiece after the electrodes have fully returned, preventing premature removal that could cause welding position shifts. This achieves post-weld process control, minimizing the impact of human error and poor positioning, and significantly improving the consistency of welding quality.

[0046] The controller can independently set and adjust the duration of the magnetic column 2 from power-on to power-off to meet different welding time requirements. The operating current of the magnetic column 2 can also be adjusted by the controller. By changing the operating current of the magnetic column 2, its magnetic force can be controlled. When using plates of different shapes and thicknesses, the current can be adjusted by the controller to meet the applicability of the anti-welding deviation mechanism under different working conditions.

[0047] Example 7 Since the support plate 1 and the nut seat welding machine, as well as the magnetic column 2 and the support plate 1, are all rigidly welded, vibration of the nut seat welding machine, foundation settlement, or long-term welding impact will cause slight deformation of the support plate 1, which will be directly transmitted to the upper surface of the magnetic column 2, causing the bonded insulating plate 3 to warp or tilt. In addition, the adhesive between the insulating plate 3 and the magnetic column 2 will experience local aging, shrinkage, or peeling under the repeated action of high welding temperatures, damaging the planar bonding relationship between the insulating plate 3 and the magnetic column 2.

[0048] Therefore, the anti-weld-off system for nut projection welding also includes a level 5, which is fixed to the edge of the lower surface of the insulating plate 3. By adding the level 5, real-time monitoring of the levelness of the working surface of the insulating plate 3 is achieved. The measuring surface of the level 5 remains parallel to the upper working surface of the insulating plate 3, ensuring the accuracy of the measurement results. During routine equipment maintenance and before each startup, operators need to check the position of the bubble on the level 5. If the bubble deviates from the center scale, it indicates that the insulating plate 3 is tilted, and the insulating plate 3 needs to be leveled. The setting of the level 5 allows for timely monitoring and adjustment of the levelness of the insulating plate 3, avoiding tilting of the insulating plate 3 due to long-term use. This prevents hidden factors such as uneven plate placement and decreased welding alignment accuracy. Level detection can fundamentally solve such problems, ensuring the long-term stable operation of the system.

[0049] Example 8 The level 5 has two parts, which are respectively fixed on two mutually perpendicular sides of the insulating plate 3, so as to realize the levelness detection of the working surface of the insulating plate 3 in two vertical directions, and improve the comprehensiveness and accuracy of the level calibration.

[0050] In this embodiment, two levels 5 are provided. One level 5 is fixed to the edge of the insulating plate 3 along its length direction to detect the levelness in that direction. The other level 5 is fixed to the edge of the insulating plate 3 along its width direction and is perpendicular to the first level 5 to detect the levelness in the width direction. The two perpendicular levels 5 can comprehensively reflect the levelness of the working surface of the insulating plate 3. For example, when the bubble in the level 5 along the length direction is offset but the bubble in the width direction is normal, it indicates that the insulating plate 3 is tilted only in the length direction; when the bubbles in both directions are offset, it indicates that the insulating plate 3 is twisted or tilted overall.

[0051] Operators can make targeted adjustments based on the indications of the two levels 5 to achieve precise calibration and ensure that the working surface of the insulation board 3 remains horizontal throughout the entire plane, providing a reliable guarantee for the flat placement of the board. It is especially suitable for welding scenarios with extremely high welding precision requirements or for welding critical components.

[0052] The above are merely preferred embodiments of this utility model, and not all embodiments. 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 nut projection welding anti-weld-off system, installed on a nut seat welding machine, characterized in that, include: A support plate is located below the lower electrode arm of the nut seat welding machine, and the support plate has a horizontal upper support surface; A magnetic column, an electromagnet structure, is connected to a magnetic power supply module that powers its coil. The magnetic column is vertically fixed to the support surface of a support plate, and its top has a horizontal upper magnetic surface. An insulating plate is horizontally disposed on the upper magnetic surface of the magnetic column. The insulating plate has a notch that exposes the positioning pin on the lower electrode arm, and the positioning pin extends upward beyond the insulating plate.

2. The anti-weld-off system for projection welding of nuts according to claim 1, characterized in that, The magnetic suction column is a plurality of magnetic suction columns, which are evenly distributed circumferentially around the axis of the positioning pin, and the upper magnetic suction surfaces of the plurality of magnetic suction columns are arranged coplanarly.

3. The nut projection welding anti-weld deviation system according to claim 1, characterized in that, The insulating board is made of a transparent material.

4. The nut projection welding anti-weld deviation system according to claim 1, characterized in that, The insulating plate is fixed to the magnetic column with adhesive.

5. The nut projection welding anti-weld deviation system according to claim 1, characterized in that, The notch is circular in shape and is coaxially arranged with the lower electrode arm. The inner diameter of the notch is larger than the diameter of the lower electrode arm.

6. The anti-weld-off system for projection welding of nuts according to claim 1, characterized in that, Also includes: The proximity sensor is located below the insulating plate; and The controller has its signal input terminal connected to the proximity sensor and the welding start button of the nut seat welding machine, and its control output terminal connected to the actuator of the nut seat welding machine.

7. The nut projection welding anti-weld deviation system according to claim 6, characterized in that, The proximity sensor has two components, and the positioning pins on the lower electrode arms of the two proximity sensors are arranged in a centrally symmetrical manner.

8. The nut projection welding anti-weld deviation system according to claim 6, characterized in that, The controller's control output terminal is also connected to the magnetic power supply module of the magnetic column.

9. The anti-weld-off system for projection welding of nuts according to claim 1, characterized in that, Also includes: The level is fixed to the edge of the lower surface of the insulating board.

10. The nut projection welding anti-weld deviation system according to claim 9, characterized in that, The level has two parts, and the two levels are fixed on two mutually perpendicular sides of the insulating plate.

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