Projection welding method for nuts and projection welding system for nuts

Abstract

A projection welding method for nuts, for use in welding nuts at at least two projection welding locations on a plate. The method comprises: positioning a first projection welding location of a plate at a welding station, controlling a nut positioning mechanism (13) to extend from a lower electrode assembly (12) and pass through a via hole at the first projection welding location of the plate, and controlling a nut feeding device (3) to place a nut at the welding station, such that the nut is sleeved onto the nut positioning mechanism (13); controlling an upper electrode assembly (11) to descend and tightly press the nut, and controlling the nut feeding device (3) to retract; controlling a welding device (1) to conduct a current until welding of the nut is completed, and controlling the nut positioning mechanism (13) to retract into the lower electrode assembly (12); when welding of the nut at the first projection welding location of the plate is completed, controlling the upper electrode assembly (11) to rise, controlling a plate conveying device (2) to shift the plate, and positioning a second projection welding location of the plate at the welding station; and repeating the above steps, until welding at all projection welding locations on the plate is completed. The method can greatly improve the production efficiency and reduce the production cost. The present invention further relates to a projection welding system for nuts.

Description

Nut projection welding method and nut projection welding system

[0001] Related applications

[0002] This disclosure claims priority to a Chinese patent application filed with the Patent Office of China on March 27, 2024, with application number CN202410360746.7 and invention name “Nut projection welding method and nut projection welding system”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to the field of welding technology, and in particular to a nut projection welding method and a nut projection welding system. Background Art

[0004] Many components on passenger cars, such as the engine, transmission, and seats, are fastened to the vehicle body and frame with bolts. Most of these nuts are projection-welded onto the panels that comprise these parts. Many of these panels (workpieces) require several to a dozen projection-welded nuts per piece.

[0005] In the existing technology, manual handling of panels is also mostly adopted, that is, loading, switching of projection welding positions and unloading all require manual participation. Although there are a few scenarios where handling robots are used, the collaborative capabilities of handling robots and welding equipment are not fully utilized.

[0006] When a handling robot grasps a plate and cooperates with the current nut projection welding machine to achieve automatic welding, welding a nut requires completing the following actions one by one: lifting the upper electrode → moving the workpiece upward → moving the workpiece horizontally → moving the workpiece downward → feeding the nut → dropping the nut → pressing the upper electrode downward → welding. Executing these steps one by one will cause the entire welding process to take a long time, resulting in low efficiency and high cost. Summary of the Invention

[0007] In view of this, the embodiments of the present disclosure provide a nut projection welding method and a nut projection welding system to eliminate or improve one or more defects existing in the prior art.

[0008] The technical solutions disclosed in this disclosure are as follows:

[0009] In a first aspect, the present disclosure provides a nut projection welding method for welding nuts at at least two projection welding positions on a plate, wherein the projection welding positions have projection welding vias, the method comprising the following steps:

[0010] Positioning the first projection welding position of the plate at the welding station, controlling the nut positioning mechanism to extend from the lower electrode assembly and pass through the through hole at the first projection welding position, and controlling the nut feeding device to place the nut at the welding station, so that the nut is placed at the first projection welding position of the plate and sleeved on the nut positioning mechanism;

[0011] Controlling the upper electrode assembly to descend and tighten the nut, and controlling the nut feeding device to retract;

[0012] After the upper electrode assembly presses the nut, controlling the welding device to conduct current until the nut welding is completed, and controlling the nut positioning mechanism to retract into the lower electrode assembly;

[0013] After the nut welding at the first projection welding position of the plate is completed, the upper electrode assembly is controlled to rise; after the nut positioning mechanism is retracted into the lower electrode assembly and the upper electrode assembly begins to rise, the plate handling device is controlled to shift the plate so that the second projection welding position is located at the welding station;

[0014] Repeat the above steps until welding is completed at each projection welding position of the plate.

[0015] In some embodiments, the upper electrode assembly is controlled to press the nut with a predetermined pressure, and the predetermined pressure is set according to any one of the specifications of the nut, the thickness of the plate, the material of the nut and the plate, and the different stages of welding the nut.

[0016] In some embodiments, after the nut is welded at the first projection welding position of the plate, the upper electrode assembly of the welding device is controlled to rise a predetermined distance so as to move it into position;

[0017] The predetermined distance is set as a minimum lifting distance based on the size and opening shape of the panel.

[0018] In some embodiments, the panel handling device is controlled to shift the panel, and the shifting mode is any one of horizontal movement, oblique movement and curved movement, or a combination of two or more.

[0019] In some embodiments, when the projection welding position of the plate is located at the welding station, the action of controlling the nut positioning mechanism to extend from the lower electrode assembly and the action of controlling the nut feeding device to place the nut at the projection welding position are coordinated and executed, so that the action with a longer standard working time starts first and the action with a shorter standard working time ends later, or the two actions end at the same time.

[0020] In some embodiments, the action of controlling the descent of the upper electrode assembly and the action of controlling the retraction of the nut feeding device are coordinated so that the action with a longer standard working time starts first and ends after the action with a shorter standard working time, or the two actions end at the same time.

[0021] In some embodiments, in a first period after the welding device is turned on, the nut positioning mechanism is controlled to start moving downward and retract into the lower electrode assembly before the nut welding is completed.

[0022] In some embodiments, after the nut is welded at the first projection welding position of the plate, in the second period after the upper electrode assembly of the welding device starts to rise or when the upper electrode assembly rises to a set height, the plate handling device is controlled to shift the plate so that its second projection welding position is located at the welding station.

[0023] In some embodiments, before the nut feeding device places the nut on the welding station, the nut feeding device is controlled to move from the picking position to the waiting position, and the waiting position is the closest position close to the welding station, which is away from the plate displacement path and the lifting and lowering movement of the upper electrode assembly.

[0024] In some embodiments, the nut feeding device is controlled to transport the nut from the nut discharging point to the welding station along an inclined path, and the inclined path is located on a side of the welding device away from the plate handling device.

[0025] In some embodiments, at least one of the nut positioning mechanism, the nut feeding device, and the upper electrode assembly of the welding device adopts a servo drive mechanism.

[0026] In some embodiments, nuts of different specifications are welded at the first projection welding position and the second projection welding position of the plate, respectively. The welding device includes a turntable upper electrode assembly and a lower electrode assembly. The upper electrode assembly and the lower electrode assembly are configured with at least two sets of electrodes for different specifications. The method further includes:

[0027] After welding the nut at the first projection welding position of the plate:

[0028] Controlling the upper electrode assembly of the welding device to rise and rotate so that the upper electrode assembly switches electrodes;

[0029] Controlling the plate transport device to shift the plate to a conversion position that avoids rotation of the electrode assembly;

[0030] Controlling the rotation of the lower electrode assembly of the welding device so that the lower electrode assembly switches electrodes;

[0031] The plate handling device is controlled to shift the plate so that its second projection welding position is located at the welding station.

[0032] In a second aspect, the present disclosure further provides a nut projection welding system for performing the aforementioned nut projection welding method, wherein the nut projection welding system includes a welding device, a plate handling device, a nut feeding device, and a control system;

[0033] The welding device comprises a coaxially arranged lower electrode assembly and a liftable upper electrode assembly, wherein the lower electrode assembly has a nut positioning mechanism capable of early extension and retraction, and the upper electrode assembly has a servo lift mechanism capable of controlling pressure and position; the welding device also comprises a welding transformer for providing welding current;

[0034] The plate handling device can at least handle the plate to change its position so that the next projection welding position to be welded is moved to the welding station;

[0035] The nut feeding device can deliver nuts of at least one specification to the welding station;

[0036] The control system is used to:

[0037] When the first projection welding position of the plate is located at the welding station, the nut positioning mechanism is controlled to extend from the lower electrode assembly and pass through the through hole at the first projection welding position of the plate, and the nut feeding device is controlled to place the nut at the welding station, so that the nut is placed at the first projection welding position of the plate and sleeved on the nut positioning mechanism;

[0038] Controlling the upper electrode assembly to descend and tighten the nut, and controlling the nut feeding device to retract;

[0039] After the upper electrode assembly presses the nut, controlling the welding device to conduct current until the nut welding is completed, and controlling the nut positioning mechanism to retract into the lower electrode assembly;

[0040] After the nut welding at the first projection welding position of the plate is completed, controlling the upper electrode assembly to rise;

[0041] After the nut positioning mechanism is retracted into the lower electrode assembly and the upper electrode assembly begins to rise, the plate transporting device is controlled to shift the plate so that the second projection welding position is located at the welding station;

[0042] Repeat the above steps until welding is completed at each projection welding position of the plate.

[0043] In a third aspect, the present disclosure further provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of the aforementioned method when executed by a processor.

[0044] The lower electrode assembly of the nut projection welding system in the embodiment of the present disclosure has a nut positioning mechanism that can be extended and retracted in advance. The nut positioning mechanism is already in a retracted state before welding is completed. When the nut welding at the projection welding position of the plate is completed and the upper electrode is slightly loosened, it can be translated without being restricted by the nut positioning mechanism, so that the path for changing the position and posture of the plate is greatly simplified, and the function of synchronous movement of the translation of the plate and the rise of the upper electrode is realized; after the next projection welding position of the plate is translated into place, the rise of the nut positioning mechanism can be synchronized with the feeding of the nut feeding device; after the nut is put down, the downward pressure of the upper electrode can be synchronized with the retreat of the nut feeding device, which can greatly improve the production efficiency of nut projection welding.

[0045] Additional advantages, objects, and features of the present disclosure will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art after studying the following or may be learned from practice of the present disclosure.

[0046] Those skilled in the art will understand that the purposes and advantages that can be achieved by the present disclosure are not limited to the above specific descriptions, and the above and other purposes that can be achieved by the present disclosure will be more clearly understood from the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The drawings described herein are intended to provide a further understanding of the present disclosure, constitute a part of this application, and do not constitute a limitation of the present disclosure. The components in the drawings are not drawn to scale, but are only for the purpose of illustrating the principles of the present disclosure. To facilitate the illustration and description of some parts of the present disclosure, the corresponding parts in the drawings may be enlarged, that is, they may be larger than other components in the exemplary devices actually manufactured according to the present disclosure. In the drawings:

[0048] FIG1 is a flowchart of a nut projection welding method according to an embodiment of the present disclosure.

[0049] FIG2 is a flowchart of a nut projection welding method in another embodiment of the present disclosure.

[0050] FIG3 is a composition diagram of a control system in an embodiment of the present disclosure.

[0051] FIG4 is a schematic structural diagram of a nut projection welding system from a front view in an embodiment of the present disclosure.

[0052] FIG5 is an enlarged view of portion A of FIG4 .

[0053] FIG6 is a schematic structural diagram of a nut projection welding system from a side view in an embodiment of the present disclosure.

[0054] FIG7 is a schematic structural diagram of a nut projection welding system from a top view in an embodiment of the present disclosure.

[0055] FIG8 is a schematic comparison of a sequential welding timing diagram in the prior art and a coordinated welding timing diagram in an embodiment of the present disclosure.

[0056] Figure markings: 1. Welding device; 11. Upper electrode assembly; 111. Servo lifting mechanism; 12. Lower electrode assembly; 13. Nut positioning mechanism; 131. Positioning member; 132. Linear drive; 14. Welding transformer; 2. Panel handling device; 21. Robot gripper; 3. Nut feeding device; 4. Control system; 41. Welding device controller; 42. Panel handling controller; 43. Nut feeding controller; 51. Panel; 52. Nut. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in conjunction with the embodiments and drawings. Here, the illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure, but are not intended to limit the present disclosure.

[0058] It should also be noted here that in order to avoid obscuring the present disclosure due to unnecessary details, only structures and / or processing steps closely related to the solutions according to the present disclosure are shown in the accompanying drawings, while other details that are not closely related to the present disclosure are omitted.

[0059] It should be emphasized that the term "include / comprises" when used herein refers to the existence of features, elements, steps or components, but does not exclude the existence or addition of one or more other features, elements, steps or components.

[0060] It should also be noted that, unless otherwise specified, the term "connection" herein may refer not only to a direct connection but also to an indirect connection involving an intermediate.

[0061] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals represent the same or similar components, or the same or similar steps.

[0062] In order to improve the low efficiency problem of existing nut projection welding processes in the fields of passenger car body-in-white, chassis, etc., the present invention provides a nut projection welding method and a nut projection welding system, so as to integrate the functional components of each action in the entire welding process of nut projection welding with a control system, so that they can coordinate with each other and move simultaneously with a more optimized workflow and a shorter path, thereby greatly reducing the auxiliary welding time, improving production efficiency and reducing production costs.

[0063] It is understandable that the "nut" in the so-called "nut projection welding equipment / nut projection welding machine" or "projection welded nut" is a continuation of the traditional naming. In fact, it not only includes nuts connected to plates using the projection welding process, but also includes other fasteners connected to plates using the projection welding process, including studs, bolts and pins.

[0064] As shown in FIG3-FIG7 , the present disclosure provides a nut projection welding system, which includes a welding device 1 , a plate handling device 2 , a nut feeding device 3 , a control system 4 , and the like.

[0065] The welding device 1 comprises a coaxially arranged lower electrode assembly 12 and a liftable upper electrode assembly 11. The coaxial arrangement can be based on the axis of the nut 52 to ensure accurate and consistent welding. The upper and lower electrode assemblies 12 are key components of the nut projection welding system, responsible for clamping the plate 51 and nut 52 and completing the welding circuit.

[0066] Generally speaking, the lower electrode assembly 12 is fixed. Before welding, the plate 51 is placed on the lower electrode assembly 12, so that the positioning pin protruding from the end surface of the lower electrode passes through the through hole (pre-stamped) at the projection welding position of the plate 51. Then, the projection welding nut 52 (the nut 52 with a raised point, hereinafter referred to as nut 52) ​​is placed at the projection welding position of the plate 51 and the nut 52 is sleeved on the positioning pin. The lower electrode assembly 12 is then lowered to tighten the nut 52, and the welding is completed by applying power. Because multiple projection welding positions of the plate 51 are welded at this position, it can be called a welding station.

[0067] In the prior art, the positioning pins of the nut projection welding machine are mostly fixed and protrude from the upper end surface of the lower electrode. This method will increase interference or obstruction to the projection welding position conversion and loading and unloading paths of the plate 51, making its movement path more restricted or rigid.

[0068] The plate described in the embodiments of the present disclosure can refer to any conductive metal plate, such as sheet metal, stamping, or thin plate, as long as it can be projection welded to the nut. The plate has a certain thickness, which should not be too large or too small, and can only be used for projection welding of the nut. The plate is pre-formed with a number of projection welding holes, and the positioning member 131 is used to coaxially position the positioning member 131 and the nut.

[0069] The lower electrode assembly 12 in the embodiment of the present disclosure has a nut positioning mechanism 13 that can be extended and retracted in advance, as shown in Figures 3 and 4. The nut positioning mechanism 13 is set in the center hole of the lower electrode assembly 12 and is used to retract into the center hole of the lower electrode assembly 12 after the nut 52 is tightened and before welding is completed (its highest point is lower than the upper end face of the lower electrode). The nut positioning mechanism 13 is already in a retracted state before welding is completed. When the nut 52 at the projection welding position of the plate 51 is welded and the upper electrode is slightly loosened, it can be translated without being restricted by the nut positioning mechanism 13, making the path of the plate 51 changing its position and posture much simpler, and realizing the function of the translation of the plate 51 and the synchronous movement of the upper electrode rising; after the next projection welding position of the plate 51 is translated into place, the nut positioning mechanism 13 rises and can be synchronized with the feeding of the nut feeding device 3; after the nut 52 is lowered, the upper electrode is pressed down and can be synchronized with the retraction of the nut feeding device 3, which can greatly shorten the cycle time of welding a nut 52.

[0070] As at least one achievable method, the main function of the nut positioning mechanism 13 is to accurately position the nut 52 during the welding process. As shown in Figure 4, the nut positioning mechanism 13 may include a positioning member 131 and a linear drive 132, etc. The positioning member 131 is used for early extension and retraction, that is, it is extended when the nut 52 needs to be positioned, and retracted after completing the positioning task. The linear drive 132 can adopt a driving device such as a cylinder and a motor to realize the extension and retraction movement of the positioning member 131. As shown in Figures 3 and 6, the linear drive 132 can be arranged below the lower electrode. The controller of the nut positioning mechanism 13 can control the movement of the early extension and retraction positioning member 131, and may include a position sensor, etc. to ensure that the early extension and retraction positioning member 131 is extended and retracted at the correct time, and trigger the corresponding action when needed.

[0071] The upper electrode assembly 11 in the embodiment of the present disclosure has a servo lifting mechanism 111 that can control pressure and position. The servo lifting mechanism 111 is used to achieve precise lifting control of the upper electrode assembly 11 and adjust the welding pressure.

[0072] As at least one possible implementation, the servo lift mechanism 111 may include a servo motor, a screw drive mechanism, a position sensor, a pressure sensor, and a servo motor controller. A servo motor is a precision electric motor capable of high-precision, high-speed motion according to the instructions of the control system 4. Here, the servo motor drives the lifting and lowering motion of the upper electrode assembly 11. The screw drive mechanism converts the servo motor's rotational motion into up-and-down motion. The screw, connected to the motor, converts the rotational motion into linear motion, thereby lifting and lowering the upper electrode assembly 11. The position sensor enables precise control of the upper electrode assembly 11's position by monitoring its actual position and providing feedback to the servo motor controller for timely adjustment of the motor's motion. The pressure sensor monitors the pressure applied by the upper electrode assembly 11 to the workpiece and transmits this pressure information to the control system 4. This feedback allows the system to adjust the servo motor's motion to maintain the desired welding pressure. The servo motor controller is the brains of the servo lift mechanism 111. It receives position information from the sensors and controls the servo motor's motion according to preset parameters and algorithms to achieve accurate lifting and lowering of the upper electrode assembly 11.

[0073] Furthermore, the welding device 1 may also include a welding transformer 14. This is a key component of the welding device 1, providing appropriate welding power by changing the voltage of the current. The welding transformer 14 can be located in the power supply of the welding device 1. As a core component of the power supply system, the welding transformer 14 can be directly connected between the power supply system and the welding device 1, and positioned within the current transmission path of the welding circuit. The welding transformer 14 plays a key role in adjusting the voltage and current within the welding device 1 to meet the requirements of the welding process and ensure the quality and stability of the weld.

[0074] The panel handling device 2 in the disclosed embodiment is capable of at least repositioning the panel 51 to move it to the welding station for the next projection welding position. The design of the panel handling device 2 must take into account the overall system requirements, ensuring stable and efficient handling under various operating conditions. The panel handling device 2 plays a key role in the automation and efficiency of the entire welding process.

[0075] As at least one achievable method, the panel handling device 2 may adopt an industrial robot (or manipulator), which includes a multi-degree-of-freedom robotic arm and a robotic gripper 21 (or called a gripper or end effector), etc. The multi-degree-of-freedom robotic arm is a mechanical part that mainly performs handling and positioning tasks. The robotic arm can have multiple joints and axes to provide multi-dimensional movement. The robotic gripper 21 is a tool for clamping the panel 51, and its design must take into account the shape and size of the panel 51 to ensure firm clamping and avoid damage. The industrial robot can perform complex handling and positioning movements in three-dimensional space through its flexible movement capabilities. The industrial robot can also include a path planning algorithm to ensure that the robot can move the panel 51 in the shortest path and most efficient manner within the working area.

[0076] The plate handling device 2 can be arranged on one side of the welding device 1, located in the working area of ​​the welding system, and can cover the handling path of the entire plate 51. The position can be flexibly adjusted according to the requirements of the system design. At the same time, the plate handling device 2 can be placed around the welding station so that after the welding of the plate 51 is completed, it can be moved to the next welding station. The plate handling device 2 needs to work in conjunction with other systems such as the welding device 1, the servo lifting mechanism 111, the nut positioning mechanism 13 and the nut feeding device 3 to ensure the coordination of the entire welding process. This requires it to communicate with the control system 4 in real time to synchronize and adjust the actions.

[0077] The panel handling device 2 using an industrial robot is highly flexible and adaptable, and can be quickly adjusted to suit different workpiece shapes and welding process requirements. Such an automated device helps improve production efficiency, reduce labor costs, and enhance the consistency and quality of the welding process.

[0078] The nut feeding device 3 in the embodiment of the present disclosure can deliver nuts 52 of at least one specification to the welding station. The main function of the nut feeding device 3 is to automatically deliver the nuts 52 from the storage area or other sources to the welding station and prepare the working materials required for welding. Through the automated feeding process, the nut feeding device 3 helps to improve the production efficiency of the welding system and reduce manual intervention and waiting time. Through the positioning and alignment device, it is ensured that the nut 52 can be accurately positioned to the predetermined position of the welding station during the transmission process for subsequent welding operations. Optionally, the nut feeding device 3 can also adapt to nuts 52 of different specifications, such as being equipped with a clamp that can clamp nuts 52 of multiple specifications, so as to achieve flexible nut 52 switching requirements, that is, a nut 52 welding machine can be used to weld multiple nuts 52 required on a stamping machine.

[0079] It is understood that if a nut 52 welding machine is used to weld multiple types of nuts 52 required for a punch press, the upper and lower electrode assemblies 12 used therein must also be switched to accommodate the different nuts 52. Multiple sets of upper and lower electrode assemblies 12 of different specifications can be correspondingly arranged on the rotatable turntable mechanism.

[0080] When dealing with nuts 52 of various specifications, it is necessary to adapt to different welding requirements, so switching the upper and lower electrode assemblies 12 is a reasonable design choice. By providing multiple sets of upper and lower electrode assemblies 12 of different specifications and mounting them on a rotatable turntable mechanism, flexible and efficient switching can be achieved to adapt to the welding of nuts 52 of different specifications.

[0081] The turntable mechanism is a rotating platform on which multiple sets of upper and lower electrode assemblies 12 of different specifications are mounted. This mechanism can rotate to align the required upper and lower electrode assemblies 12 at the welding station. This design allows multiple sets of electrode assemblies to be accommodated on a single welding machine without stopping the machine or replacing the equipment. The turntable mechanism can be equipped with an automatic switching system that automatically selects and rotates to the appropriate electrode assembly based on the welding task. This automated design helps improve production efficiency, reduces switching time, and minimizes operator intervention. Each set of upper and lower electrode assemblies 12 may have fixing and adjustment mechanisms to ensure accurate positioning and appropriate welding pressure during welding. These mechanisms can adjust the position and angle of the electrodes to accommodate nuts 52 of different specifications. Through this design, the welding device 1 can quickly and flexibly switch between nuts 52 of different specifications, improving the system's applicability and production efficiency. This multifunctional nut projection welding machine is suitable for situations where multiple specifications of nuts 52 need to be processed on the production line.

[0082] On the other hand, as shown in FIG1 , the present disclosure provides a nut projection welding method for welding nuts 52 at at least two projection welding positions on a plate 51 , the method comprising the following steps:

[0083] S10: The first projection welding position of the plate 51 is positioned at the welding station, the nut positioning mechanism 13 is controlled to extend from the lower electrode assembly 12 and pass through the through hole at the first projection welding position of the plate, and the nut feeding device 3 is controlled to place the nut 52 at the welding station, so that the nut 52 is placed at the first projection welding position of the plate 51 and is sleeved on the nut positioning mechanism 13;

[0084] S20: Control the upper electrode assembly 11 to descend and tighten the nut 52, and control the nut feeding device 3 to retract;

[0085] S30: After the upper electrode assembly presses the nut, the welding device 1 is controlled to conduct current until the nut welding is completed, and the nut positioning mechanism 13 is controlled to be retracted into the lower electrode assembly 12;

[0086] S40: After the nut 52 at the first projection welding position of the plate 51 is welded, the upper electrode assembly 11 is controlled to rise; after the nut positioning mechanism is retracted into the lower electrode assembly and the upper electrode assembly begins to rise, the plate handling device 2 is controlled to shift the plate 51 so that its second projection welding position is located at the welding station;

[0087] S50: Repeat the above steps until welding is completed at each projection welding position of the plate 51.

[0088] In the above step S10, it is mainly used to realize positioning the first projection welding position and placing the nut 52. Among them, the first projection welding position of the plate 51 can be placed manually, or it can be placed automatically using the plate handling device 2. The first projection welding position of the plate 51 is positioned at the welding station, and the nut positioning mechanism 13 is controlled to extend from the lower electrode assembly 12 and pass through the through hole of the first projection welding position. The nut 52 is placed at the welding station through the nut feeding device 3 to ensure that the nut 52 is sleeved on the nut positioning mechanism 13. In the above step S20, it is mainly used to realize the descent of the upper electrode assembly 11 and the tightening of the nut 52, control the descent of the upper electrode assembly 11, and tighten the nut 52 with a certain pressure. At the same time, the nut feeding device 3 is controlled to retract it.

[0089] In step S30, the welding process primarily involves welding the first projection welding position. The welding apparatus 1 is controlled to conduct current and begin welding the nut 52 at the first projection welding position. Welding at the first projection welding position requires a certain amount of time. After welding begins, the nut positioning mechanism 13 can be retracted into the lower electrode assembly 12 to ensure welding accuracy and avoid restricting the movement of the plate 51. This retraction can be completed before or after the nut welding is completed. The only requirement is to ensure that the nut positioning mechanism 13 is retracted into the lower electrode assembly 12 before the plate 51 is displaced.

[0090] In step S40, the upper electrode assembly 11 is raised and the plate 51 is displaced. After the upper electrode assembly 11 has been displaced (slightly loosening the plate is sufficient) but before it is fully positioned, the upper electrode assembly 11 is controlled to rise. The plate handling device 2 shifts the plate 51 to ensure that the second projection welding position is located at the welding station. These steps can be repeated repeatedly to weld nuts 52 at different projection welding positions until all welding tasks are completed.

[0091] In the above embodiment, the method ensures efficient and consistent welding by gradually controlling the movement of each stage to adapt to different welding processes and the requirements of the plate 51. This method has a high degree of automation and can be adapted to the welding of nuts 52 of at least one specification, thereby improving the efficiency of the welding production line.

[0092] Through a spatial analysis of the functions of various functional components during nut projection welding, it is determined that during the welding cycle of each nut 52, the nut 52 completes its positioning function when it is pressed by the upper electrode. Even if it retracts at this point, it will not affect the welding position accuracy of the nut 52. Therefore, the nut projection welding method and system of the disclosed embodiments design the nut positioning mechanism 13 to be able to retract or raise and lower it in advance, which has significant advantages in improving production efficiency, shortening cycle time, and improving system stability.

[0093] The nut positioning mechanism 13 is in a retracted state before welding is completed, so that the nut positioning mechanism 13 can also avoid being affected by welding, such as reducing the impact of welding slag spattering or high temperature, thereby increasing its service life; the nut positioning mechanism 13 is in a retracted state before the punching machine welding is completed, which can realize the function of synchronous movement of the plate 51 and the upper electrode rising after welding is completed, reducing unnecessary movement of the plate 51 and the plate handling device 2, greatly shortening the cycle time of welding a nut 52, and improving the coordinated mobility of the entire system, thereby greatly improving the efficiency and production capacity of the production line.

[0094] In some embodiments, the upper electrode assembly 11 is controlled to press the nut 52 with a predetermined pressure, and the predetermined pressure is set according to any one of the specifications of the nut 52, the thickness of the plate 51, the material of the nut 52 and the plate 51, and the different stages of welding the nut 52. Controlling the upper electrode assembly 11 to press the nut 52 with a predetermined pressure is a key operation. This predetermined pressure can be set according to a variety of factors to ensure that the nut 52 is properly compressed during the welding process. The electrode pressure should be such that the bumps can be completely crushed when they reach the welding temperature and the two workpieces can be tightly fitted. Excessive electrode pressure will crush the bumps prematurely, lose the effect of projection welding, and reduce the joint strength due to the reduction in current density; too little pressure will cause severe spattering. The magnitude of the electrode pressure affects both heat absorption and heat dissipation.

[0095] In the above embodiment, different specifications of nuts 52 can use different pressures to ensure the firmness of welding, and the specifications include diameter, height, thread size, etc. The thickness of the plate 51 will affect the contact surface between the nut 52 and the plate 51, so the predetermined pressure needs to be adjusted according to the thickness to ensure uniformity of the pressing. For example, when the plate thickness is 1 mm, the pressure is 500 to 800 N; when the plate thickness is 5 mm, the pressure is 5000 to 6000 N. Different materials may have different requirements for welding pressure. The setting of the predetermined pressure can take into account the material of the nut 52 and the plate 51 to ensure the quality of the welding, such as low carbon steel, low alloy steel and HSLA steel. Different pressures can be applied at different stages of the welding process. For example, a smaller pressure may be required in the initial positioning stage, while a larger pressure may be required during the welding stage.

[0096] In the above embodiment, the above factors can be monitored and adjusted by sensors and / or control system 4. For example, sensors can measure the size and material or pressure of the nut 52 and plate 51, as well as the actual situation during the welding process, or the control system 4 can read the specifications of the nut 52 delivered by the nut feeding device 3, and the corresponding pressures of nuts 52 of different specifications are stored in the control system 4 in advance; the control system 4 dynamically adjusts the clamping force of the upper electrode assembly 11 based on these measurement results and preset specifications to meet different requirements during the welding process.

[0097] In some embodiments, after the nut 52 is welded at the first projection welding position of the plate 51, the upper electrode assembly 11 of the welding device 1 is controlled to rise a predetermined distance so that it moves into position; the predetermined distance is set as the minimum lifting distance based on the size and opening shape of the plate 51.

[0098] In this embodiment, the upper electrode assembly 11 of the welding apparatus 1 is controlled to rise so that the plate 51 can be moved to the next projection welding position, i.e., the second projection welding position. The predetermined rise distance can be a pre-set distance or calculated, for example, by automatically measuring the structural dimensions of the plate 51 using a visual inspection system. The predetermined distance is minimized to improve overall production efficiency. Setting a minimum lift distance reduces system idle time, meaning that after completing one weld, the plate 51 can be moved to the next projection welding position as quickly as possible without wasting additional time. The dimensions and opening shape of the plate 51 can include dimensional parameters such as height and width.

[0099] In the above embodiment, the minimum lifting distance design allows the method to quickly move to the next projection welding position after welding is completed, minimizing the time spent in the unwelded state and improving the efficiency of the entire nut projection welding system. This automated control method helps ensure rapid switching and efficient operation of the system between different welding tasks.

[0100] In some embodiments, the panel handling device 2 is controlled to shift the panel 51, and the shifting method is any one of horizontal movement, oblique movement and curved movement, or a combination of two or more. As a variety of achievable methods, first, the panel handling device 2 can move in the horizontal direction, that is, horizontal movement forward and backward, left and right. This method is suitable for situations where it is necessary to simply translate the panel 51 in the horizontal direction. Second, the panel handling device 2 can move in an oblique manner, that is, move in the horizontal and vertical directions at the same time. This method is very useful for situations where it is necessary to adjust the position of the panel 51 obliquely. Third, the panel handling device 2 can move along a predetermined curved path. This method is suitable for situations where it is necessary to move the panel 51 along a complex trajectory, such as when it is necessary to bypass other mechanical components or obstacles. Fourth, the panel handling device 2 can adopt a combination of two or more shifting methods. For example, it can first move horizontally and then move obliquely to adjust the position of the panel 51 more flexibly.

[0101] The diverse displacement methods described above allow the system to select the most appropriate movement method based on the specific positional variations between the two projection weld nuts, the shape and size of the stamped part, and production requirements. This flexibility helps improve the system's adaptability, ensuring that the plate 51 can be effectively moved and positioned in various situations for accurate welding operations.

[0102] In some embodiments, when the projection welding position of the plate 51 is located at the welding station, the control of the nut positioning mechanism 13 extending from the lower electrode assembly 12 and the control of the nut feeding device 3 placing the nut 52 at the projection welding position are coordinated, so that the action with the longer standard working time begins first and the action with the shorter standard working time ends later, or both actions end simultaneously. This method can coordinate the two actions to complete them in the shortest possible time, significantly reducing the welding preparation time for a single nut.

[0103] In the above embodiment, the nut positioning mechanism 13 is controlled to extend from the lower electrode assembly 12. The purpose of this action is to allow the components of the positioning mechanism (which may be positioning pins, etc.) to pass through the through-holes at the projection welding position of the nut 52 to achieve accurate positioning. At the same time, the nut feeding device 3 is controlled to place the nut 52 of predetermined specifications on the welding station. This action can be to move the nut 52 to the projection welding position by automatic feeding or other means. Once the nut 52 is fed into the projection welding position, the components of the nut positioning mechanism 13 cooperate with the through-holes at the projection welding position of the nut 52 to ensure that the nut 52 is accurately positioned on the welding station, that is, it is sleeved on the positioning component.

[0104] This method of simultaneously performing nut 52 positioning and nut 52 placement can reduce the time of a single welding cycle and improve the efficiency of the entire system. By performing these two key steps in parallel while the plate 51 is in the welding station state, the system can perform welding operations more quickly, thereby improving productivity.

[0105] In some embodiments, the action of controlling the lowering of the upper electrode assembly 11 and the action of controlling the retraction of the nut feeding device 3 are coordinated, so that the action with the longer standard working time begins first and the action with the shorter standard working time ends later, or both actions end simultaneously. This method can coordinate the two actions to complete them in the shortest possible time, significantly reducing the preparation time for welding a single nut.

[0106] In the above embodiment, the upper electrode assembly 11 is controlled to descend, pressing against the nut 52 and completing the weld. This action ensures the weld is secure. Simultaneously, the nut feeder 3 is controlled to retract to an appropriate position. This action may be to return the nut feeder 3 to its starting position, ready to receive the next nut 52. Completion of these steps indicates that the system is ready for the next welding cycle, allowing welding operations on the nut 52 at the welding station and the receipt of a new nut 52.

[0107] In some embodiments, during the first period after the welding device 1 is turned on, the nut positioning mechanism 13 is controlled to start moving downward and retract into the lower electrode assembly 12 before the nut welding is completed. In the above embodiment, during the first period after the welding device 1 is turned on, the control system 4 starts the downward movement of the nut positioning mechanism 13. The nut positioning mechanism 13 starts to move downward, which can be achieved by hydraulics, motors or other appropriate drive mechanisms. Before the end of welding, the nut positioning mechanism 13 is completely retracted into the lower electrode assembly 12, which ensures that before the next round of welding, the nut positioning mechanism 13 will not impose any restrictions or influence on the movement of the plate 51.

[0108] In the above embodiment, the total duration of the conduction current can be divided into different time periods, of which the first time period occupies a certain proportion, such as the first 20% or 30%, etc. The specific proportion can be determined based on the critical state of melting of the nut 52 protrusion, or the critical state of starting to generate welding slag, or based on the retraction working time of the nut positioning mechanism 13. It is necessary to ensure that before the welding is completed, the nut positioning mechanism 13 can be completely retracted into the lower electrode assembly 12 (the top of the nut positioning mechanism 13 is retracted below the upper surface of the lower electrode). In addition, the setting of the first time period can be based on the consideration of optimizing the welding process and ensuring the stability and reliability of the system during each welding cycle. The specific proportion will be affected by the specific system design and welding process requirements. In practice, this proportion can be adjusted and optimized according to actual needs.

[0109] In some embodiments, after the nut 52 is welded at the first projection welding position of the plate 51, in the second period after the upper electrode assembly 11 of the welding device 1 starts to rise or when the upper electrode assembly 11 rises to a set height (this height may also be zero, or a decimal close to zero), the plate handling device 2 is controlled to shift the plate 51 so that its second projection welding position is located at the welding station. The upper electrode assembly 11 of the welding device 1 is controlled to start rising so that the upper electrode is separated from the welding station and the next projection welding position of the plate 51 is prepared to be shifted to the welding station. The second period after the upper electrode assembly 1 starts to rise, or when the upper electrode assembly 11 rises to the set height, is the critical time point to start the plate handling device 2. When the plate handling device 2 is started at this time, the plate 51 will not interfere with or collide with the upper electrode assembly 11.

[0110] In the above embodiment, when applied to the body-in-white of a passenger car, since the moving stroke of the upper electrode assembly 11 is shorter and it moves first, and the projection welding position distance of the panel 51 is generally longer, the standard working time of the panel handling device 2 controlling the movement of the panel 51 may be longer than the standard working time of the movement of the upper electrode assembly 11. Therefore, when performing subsequent actions, the completion of the displacement action of the panel 51 by the panel handling device 2 can be used as a starting mark for the subsequent actions.

[0111] In some embodiments, before the nut feeding device 3 places the nut 52 on the welding station, the nut feeding device 3 is controlled to move from the picking position to the waiting position, and the waiting position is the closest position close to the welding station, which is away from the displacement path of the plate 51 and the lifting and lowering movement of the upper electrode assembly 11.

[0112] In the above embodiment, the nut feeding device 3 is designed with a pick-up position, that is, the place where the nut 52 is taken out or taken to this position. Before the nut 52 is fed into the welding station, the nut feeding device 3 is controlled to move from the pick-up position to the waiting position. This waiting position can be the closest position close to the welding station, that is, the position is designed to avoid the displacement path of the plate 51 and the area of ​​the lifting and lowering movement of the upper electrode assembly 11. Make sure that the waiting position is set outside the displacement path of the plate 51 to prevent the nut feeding device 3 from colliding with the moving plate 51. Similarly, make sure that the waiting position will not be affected by the lifting and lowering movement of the upper electrode assembly 11 to avoid collision between the two.

[0113] By moving the nut feeding device 3 to a waiting position close to the welding station and avoiding the displacement path of the plate 51 and the lifting and lowering movement of the upper electrode assembly 11 before the nut 52 is fed into the welding station, the system can ensure a safe distance between the various components during the welding process, avoid interference and collision, and thus improve the safety and reliability of the welding operation.

[0114] In some embodiments, the nut feeding device 3 is controlled to transport the nut 52 from the ejection point to the welding station along an inclined path, and the inclined path is located on the side of the welding device 1 away from the panel handling device 2. The nut feeding device 3 usually has a ejection point, that is, the place where the nut 52 is released from the device. An inclined path is designed, which runs along the side of the welding device 1 away from the panel handling device 2. The inclined path is designed to provide an inclined direction during the conveying of the nut 52, so that the nut 52 moves along the path toward the welding station. The nut feeding device 3 is controlled to move along the inclined path to transport the nut 52 from the ejection point to the welding station. The design of the inclined path takes into account the distance from the panel handling device 2 to avoid conflict with the movement path of the panel handling device 2.

[0115] The use of an inclined path to convey the nut 52 allows for a smooth transition from the discharge point to the welding station, while ensuring that the nut 52 does not collide or interfere with the panel handling device 2 during the conveying process. This design helps improve the stability and safety of the system, ensuring that the nut 52 can be smoothly and accurately conveyed to the welding station.

[0116] In some embodiments, at least one of the nut positioning mechanism 13, the nut feeding device 3, and the upper electrode assembly 11 of the welding apparatus 1 utilizes a servo drive mechanism. This servo drive mechanism provides high-precision position, velocity, and force control, ensuring the accuracy of the welding operation. It can adjust motion parameters based on real-time requirements to accommodate varying welding conditions and workpiece characteristics. The servo drive mechanism exhibits rapid response, enabling rapid motion changes and enhancing system flexibility. The servo drive mechanism is programmable and can be flexibly adjusted to meet the requirements of different welding tasks, enabling diverse welding operations.

[0117] As at least one achievable method, the servo drive mechanism of the nut positioning mechanism 13 can be used to achieve accurate positioning and telescopic control of the nut 52. The servo drive system can provide high-precision position control to ensure the accurate positioning of the nut 52 on the welding station and realize the function of early telescopic extension when necessary. In addition, the nut feeding device 3 using the servo drive mechanism can have a precise feeding control function. The servo system can achieve high-speed and high-precision delivery of the nut 52 to ensure that each nut 52 can be accurately placed on the welding station. In addition, the servo drive mechanism can be used to control the up and down movement in the upper electrode assembly 11 to ensure the clamping force and position control during welding, which helps to improve the welding quality and consistency.

[0118] In some embodiments, as shown in Figure 2, the first projection welding position and the second projection welding position of the plate 51 are respectively welded to nuts 52 of different specifications, and the welding device 1 includes a turntable upper electrode assembly 11 and a lower electrode assembly 12, and the upper electrode assembly 11 and the lower electrode are configured with at least two groups of electrodes for different specifications.

[0119] After the nut 52 is welded at the first projection welding position of the plate 51, the method further includes:

[0120] S41: controlling the upper electrode assembly 11 of the welding device 1 to rise and rotate, so that the upper electrode assembly 11 switches electrodes;

[0121] S42: Control the plate transporting device 2 to shift the plate 51 to a switching position that avoids rotation of the electrode assembly;

[0122] S43: controlling the lower electrode assembly 12 of the welding device 1 to rotate so that the lower electrode assembly 12 switches electrodes;

[0123] S44: Control the panel transporting device 2 to shift the panel 51 so that its second projection welding position is located at the welding station.

[0124] In the above embodiment, the welding system is designed to be able to weld nuts 52 of different specifications. After the nuts 52 are welded at the first projection welding position of the plate 51, it is necessary to switch the electrodes to accommodate nuts 52 of different specifications at the second projection welding position. The upper electrode assembly 11 of the welding device 1 is controlled to rise, and can be accompanied by a rotation operation to switch the upper electrode assembly 11 to an electrode suitable for the second projection welding position. The upper electrode assembly 11 needs to be raised to an appropriate height and its angle adjusted. The plate handling device 2 is controlled to shift the plate 51 to ensure that the plate 51 moves to a position that avoids conflict with the conversion position when the upper electrode assembly 1 rotates. The lower electrode assembly 12 of the welding device 1 is controlled to rotate to switch to an electrode suitable for the second projection welding position. The plate handling device 2 is controlled to shift the plate 51 again so that its second projection welding position is located at the welding station.

[0125] Through this operational process, the welding system can switch electrodes during the welding process to accommodate nuts 52 of varying specifications. This design allows for welding of multiple nuts 52 specifications within a single system, enhancing the system's flexibility and adaptability. With the implementation of automation, this switching process can be completed more efficiently, reducing production time.

[0126] The nut projection welding system provided by the present disclosure is used to perform the above-mentioned nut projection welding method. The nut projection welding system includes a welding device 1, a plate handling device 2, a nut feeding device 3 and a control system 4.

[0127] The control system 4 is used to control the nut positioning mechanism 13 to extend from the lower electrode assembly 12 and pass through the through hole of the first projection welding position when the first projection welding position of the plate 51 is located at the welding station, and control the nut feeding device 3 to place the nut 52 at the welding station so that the nut 52 is located at the first projection welding position of the plate 51 and is sleeved on the nut positioning mechanism 13; the control system 4 is also used to control the upper electrode assembly 11 to descend and press the nut 52, and control the nut feeding device 3 to retract; the control system 4 is also used to control the upper electrode assembly 11 to press the nut 52 after the upper electrode assembly 11 presses the nut. Control the welding device 1 to conduct current until the nut welding is completed, and control the nut positioning mechanism 13 to be retracted into the lower electrode assembly 12; the control system 4 is also used to control the upper electrode assembly 11 to rise after the nut welding at the first projection welding position of the plate is completed; after the nut positioning mechanism 13 is retracted into the lower electrode assembly 12, and after the upper electrode assembly 11 starts to rise, control the plate handling device 2 to shift the plate and make its second projection welding position located at the welding station; the control system 4 is also used to control the repetition of the above steps until the welding of each projection welding position of the plate 51 is completed.

[0128] In the above embodiment, as shown in Figure 7, the control system 4 may include a welding device controller 41, a panel handling controller 42, and a nut feed controller 43. The control system 4 is the core of the entire system, responsible for coordinating and controlling the movements of various components to complete the projection welding operation of the nut 52. The welding device controller 41 is responsible for controlling various movements of the welding device 1, including the lifting and rotation of the upper electrode assembly 11, current conduction control, etc. The welding device controller 41 can ensure the accuracy and consistency of the welding operation according to the predetermined welding program. The panel 51 handling controller is used to control the movement of the panel handling device 2, enabling it to move the panel 51 to different welding stations. The panel handling controller 42 can also coordinate the horizontal, diagonal, or curved movement paths of the panel handling device 2 to meet the needs of the system. The nut feed controller 43 is used to control the movement of the nut feed device 3, ensuring that the nut 52 is delivered to the welding station at the appropriate time. This involves operations such as the removal, delivery, and placement of the nut 52.

[0129] Through the control system 4, the entire nut projection welding system can achieve welding of nuts 52 of different specifications, accurately positioning the nuts 52, coordinating the upper and lower electrode assemblies 12, and shifting the plate 51. This automated control system 4 helps improve welding efficiency, accuracy, and consistency.

[0130] Example 1

[0131] To further explain in detail the nut projection welding system and method in the embodiment of the present disclosure, FIG8 is a comparison of the sequential action welding timing diagram in the prior art and the coordinated action welding timing diagram in the embodiment of the present disclosure.

[0132] It can be seen that the sequential welding method in the prior art requires the execution of 8 steps, namely:

[0133] (1) The handling robot drives the plate 51 to rise and leave the nut 52 positioning pin. The standard working time is 0.5s.

[0134] (2) The handling robot drives the plate 51 to change its position and posture so that the next hole is located above the positioning pin of the nut 52. The standard working time is 0.8s.

[0135] (3) The handling robot drives the plate 51 downward, so that the positioning pin of the nut 52 penetrates the through hole of the plate 51. The standard working time is 0.5s.

[0136] (4) The nut 52 is fed into the feeding mechanism and the nut 52 is put on the nut 52 positioning pin. The standard working time is 0.5s.

[0137] (5) The nut 52 is fed into the mechanism and retracted, with a standard working time of 0.5s;

[0138] (6) The upper electrode lifting mechanism descends to tighten the nut 52 and the plate 51. The standard working time is 0.5s.

[0139] (7) The welding controller conducts current and welds the projection nut 52. The standard working time is 1 second.

[0140] (8) The upper electrode lifting mechanism loosens the nut 52 and the plate 51 and raises them into position. The standard working time is 0.6s.

[0141] Since each action is connected in sequence, the total time consumed for welding a nut 52 is the sum of the standard working hours of each action, which is 4.9 seconds.

[0142] The coordinated welding method in the embodiment of the present disclosure requires the execution of four steps, namely:

[0143] (1) The upper electrode lifting mechanism loosens the nut 52 and the plate 51 and rises to its position, with a standard working time of 0.4s. After a delay of 0.1s, the handling robot drives the plate 51 to change to the position for welding the next nut 52, with a standard working time of 0.8s.

[0144] (2) The positioning pin of the nut 52 is driven by the cylinder to pass through the through hole of the lower electrode and the plate 51. The standard working time is 0.5s. The nut 52 is clamped and fed into the feeding mechanism. After the nut 52 is in place, the nut 52 is loosened so that it is sleeved on the positioning pin of the nut 52. The standard working time is 0.4s. The two are performed synchronously.

[0145] (3) The nut 52 feeding mechanism retracts, with a standard working time of 0.4s; the upper electrode lifting mechanism descends, pressing the nut 52 and the plate 51 together, with a standard working time of 0.4s; both are performed simultaneously;

[0146] (4) The welding controller turns on the current and welds the projection nut 52, with a standard working time of 1 second. After a delay of 0.2 seconds, the positioning pin of the nut 52 is retracted from the through hole of the plate 51 under the drive of the cylinder, with a standard working time of 0.4 seconds.

[0147] Because the various actions are coordinated under the control of control system 4, the total time required to weld a nut 52 in one working cycle of the original projection welding machine is reduced to 2.8 seconds, compared to 4.9 seconds in the existing technology, a 43% reduction in time. Compression of the actions into the existing four steps can significantly improve production efficiency and reduce production costs.

[0148] In the comparison diagram of the above different action modes, the standard working hours of "the robot drives the plate 51 to change its posture" will vary due to factors such as different factors such as the amplitude of position and posture change. The standard working hours for welding the nut 52 will also vary due to factors such as the specifications of the nut 52 and the thickness of the plate. Therefore, the improvement in work efficiency will fluctuate slightly, which is only illustrated here as an example.

[0149] Through theoretical deduction and experimental verification, the high-efficiency nut projection welding system and method in the embodiment of the present disclosure can improve the production efficiency of nut projection welding by 30% to 60% after being industrialized in the fields of passenger car body-in-white, chassis, etc., which are widely used. The more projection welding nuts 52 that need to be welded on each plate 51, the more obvious the improvement in production efficiency, and the manufacturing and management costs will be greatly reduced.

[0150] In a third aspect, an embodiment of the present disclosure further provides a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, the steps of the aforementioned method are implemented.

[0151] The present invention integrates the functional components of each action in the entire welding process with a control system, so that they can coordinate with each other and move simultaneously in a more optimized workflow and a shorter path, greatly reducing the auxiliary welding time.

[0152] It should be understood by those skilled in the art that the various exemplary components, systems, and methods described in conjunction with the embodiments disclosed herein can be implemented in hardware, software, or a combination of both. Whether the implementation is performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this disclosure. When implemented in hardware, it can be, for example, an electronic circuit, an application-specific integrated circuit (ASIC), appropriate firmware, a plug-in, a function card, etc. When implemented in software, the elements of this disclosure are programs or code segments used to perform the required tasks. The program or code segment can be stored in a machine-readable medium or transmitted over a transmission medium or communication link via a data signal carried in a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, radio frequency (RF) links, etc. The code segments can be downloaded via a computer network such as the Internet or an intranet.

[0153] It should also be noted that the exemplary embodiments described in this disclosure describe methods or systems based on a series of steps or devices. However, this disclosure is not limited to the order of the steps described above. In other words, the steps may be performed in the order described in the embodiments, or in a different order, or several steps may be performed simultaneously.

[0154] The software may be placed in random access memory (RAM), memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0155] In the present disclosure, features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or combined with or replace features of other embodiments.

[0156] The foregoing description is merely a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. Those skilled in the art will readily appreciate that various modifications and variations of the present disclosure are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present disclosure shall be within the scope of protection of the present disclosure.

Claims

1. A nut projection welding method for welding nuts at at least two projection welding positions on a plate, wherein the projection welding positions have projection welding vias, characterized in that: The method comprises the following steps: The first projection welding position of the plate is positioned at the welding station, the nut positioning mechanism is controlled to extend from the lower electrode assembly and pass through the through hole at the first projection welding position of the plate, and the nut feeding device is controlled to place the nut at the welding station, so that the nut is placed at the first projection welding position of the plate and sleeved on the nut positioning mechanism; Controlling the upper electrode assembly to descend and tighten the nut, and controlling the nut feeding device to retract; After the upper electrode assembly presses the nut, controlling the welding device to conduct current until the nut welding is completed, and controlling the nut positioning mechanism to retract into the lower electrode assembly; After the nut welding at the first projection welding position of the plate is completed, the upper electrode assembly is controlled to rise; after the nut positioning mechanism is retracted into the lower electrode assembly and the upper electrode assembly begins to rise, the plate handling device is controlled to shift the plate so that the second projection welding position is located at the welding station; Repeat the above steps until welding is completed at each projection welding position of the plate.

2. The nut projection welding method according to claim 1, characterized in that: The upper electrode assembly is controlled to press the nut with a predetermined pressure, and the predetermined pressure is set according to any one of the specifications of the nut, the thickness of the plate, the materials of the nut and the plate, and different stages of welding the nut.

3. The nut projection welding method according to claim 1, characterized in that: After the nut is welded at the first projection welding position of the plate, the upper electrode assembly of the welding device is controlled to rise a predetermined distance so as to move it into position; The predetermined distance is set as a minimum lifting distance based on the size and opening shape of the panel.

4. The nut projection welding method according to claim 1, characterized in that: The panel handling device is controlled to shift the panel, and the shifting mode is any one of horizontal movement, oblique movement and curved movement, or a combination of two or more.

5. The nut projection welding method according to claim 1, characterized in that: When the projection welding position of the plate is located at the welding station, the action of controlling the nut positioning mechanism to extend from the lower electrode assembly and the action of controlling the nut feeding device to place the nut on the projection welding position are coordinated and performed so that the action with a longer standard working time starts first and the action with a shorter standard working time ends later, or the two actions end simultaneously; and / or, The action of controlling the descent of the upper electrode assembly and the action of controlling the retraction of the nut feeding device are coordinated and executed so that the action with a longer standard working time starts first and the action with a shorter standard working time ends later, or the two actions end at the same time.

6. The nut projection welding method according to claim 1, characterized in that: In a first period after the welding device conducts current, controlling the nut positioning mechanism to start moving downward and retracting into the lower electrode assembly before nut welding is completed; and / or, After the nut is welded at the first projection welding position of the plate, in the second period after the upper electrode assembly of the welding device starts to rise or when the upper electrode assembly rises to a set height, the plate handling device is controlled to shift the plate so that its second projection welding position is located at the welding station.

7. The nut projection welding method according to any one of claims 1 to 6, characterized in that: Before the nut feeding device places the nut on the welding station, the nut feeding device is controlled to move from the picking position to the waiting position, wherein the waiting position is the closest position to the welding station and avoids the plate displacement path and the lifting movement of the upper electrode assembly; and / or The nut feeding device is controlled to transport the nut from the nut discharging point to the welding station along an inclined path, and the inclined path is located on a side of the welding device away from the plate handling device.

8. The nut projection welding method according to any one of claims 1 to 6, characterized in that: At least one of the nut positioning mechanism, the nut feeding device and the upper electrode assembly of the welding device adopts a servo drive mechanism.

9. The nut projection welding method according to claim 1, characterized in that: The first projection welding position and the second projection welding position of the plate are respectively welded with nuts of different specifications, the welding device includes a turntable upper electrode assembly and a lower electrode assembly, the upper electrode assembly and the lower electrode assembly are configured with at least two groups of electrodes for different specifications, and the method further includes: After welding the nut at the first projection welding position of the plate: Controlling the upper electrode assembly of the welding device to rise and rotate so that the upper electrode assembly switches electrodes; Controlling the plate transport device to shift the plate to a conversion position that avoids rotation of the electrode assembly; Controlling the rotation of the lower electrode assembly of the welding device so that the lower electrode assembly switches electrodes; The plate handling device is controlled to shift the plate so that its second projection welding position is located at the welding station.

10. A nut projection welding system, characterized in that: Used to perform the nut projection welding method according to any one of claims 1 to 9, the nut projection welding system comprises a welding device, a plate handling device, a nut feeding device and a control system; The welding device comprises a coaxially arranged lower electrode assembly and a liftable upper electrode assembly, wherein the lower electrode assembly has a nut positioning mechanism capable of early extension and retraction, and the upper electrode assembly has a servo lift mechanism capable of controlling pressure and position; the welding device also comprises a welding transformer for providing welding current; The plate handling device can at least handle the plate to change its position so that the next projection welding position to be welded is moved to the welding station; The nut feeding device can deliver nuts of at least one specification to the welding station; The control system is used to: When the first projection welding position of the plate is located at the welding station, the nut positioning mechanism is controlled to extend from the lower electrode assembly and pass through the through hole at the first projection welding position of the plate, and the nut feeding device is controlled to place the nut at the welding station, so that the nut is placed at the first projection welding position of the plate and sleeved on the nut positioning mechanism; Controlling the upper electrode assembly to descend and tighten the nut, and controlling the nut feeding device to retract; After the upper electrode assembly presses the nut, controlling the welding device to conduct current until the nut welding is completed, and controlling the nut positioning mechanism to retract into the lower electrode assembly; After the nut welding at the first projection welding position of the plate is completed, controlling the upper electrode assembly to rise; After the nut positioning mechanism is retracted into the lower electrode assembly and the upper electrode assembly begins to rise, the plate transporting device is controlled to shift the plate so that the second projection welding position is located at the welding station; Repeat the above steps until welding is completed at each projection welding position of the plate.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 9 are implemented.

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