Variable pitch automatic welding mechanism and welding method thereof

Abstract

The application discloses a variable-distance automatic welding mechanism and a welding method thereof, which comprises a linear module arranged along the X-axis direction, a first mounting plate fixedly arranged on the linear module, a second mounting plate driven by the linear module, a first rotary lifting welding assembly arranged on the first mounting plate, and a second rotary lifting welding assembly arranged on the second mounting plate. The first rotary lifting welding assembly and the second rotary lifting welding assembly can rotate and lift independently. The linear module drives the second mounting plate to drive the second rotary lifting welding assembly to move along the X-axis direction. The horizontal distance between the two welding assemblies can be steplessly adjusted according to the actual span of two welds on the same automobile sheet metal part, so that the two welding assemblies can be synchronously positioned after one positioning, and external mechanical arms are not needed to be repeatedly adjusted or welded in batches.

Description

Technical Field

[0001] This invention relates to the field of welding, specifically to a variable-pitch automatic welding mechanism and its welding method. Background Technology

[0002] In the welding process of automotive sheet metal parts, there are often multiple weld seams on the same sheet metal part. For example, two weld seams at different locations on the same workpiece need to be welded separately. To improve welding efficiency, some double-head or multi-head welding devices have emerged in the prior art. For example, Chinese Patent No. CN216990310U discloses a double welding clamp spot welding device, including a bracket, a mounting base fixed on the bracket, and a first welding clamp and a second welding clamp mounted on the mounting base. The first welding clamp is fixed to the mounting base, and the second welding clamp can move linearly relative to the mounting base to change the distance between the two welding clamps. A grinding mechanism is provided at both ends of the front of the bracket, with one grinding mechanism corresponding vertically to the position of the first welding clamp. Although this utility model enables simultaneous welding of two weld points with different distances, reduces part welding time, improves production efficiency, and reduces production costs, it still has the following shortcomings: First, in existing double-head welding devices, the horizontal distance between the two welding heads is mostly a fixed value or can only be roughly adjusted manually. It is impossible to make stepless and precise adjustments based on the actual horizontal span of the two welds on the same sheet metal part. It is also difficult to make the two welding heads synchronously aligned to the starting position of their respective welds after one positioning. It often requires repeated adjustments by an external robotic arm or welding in stages, which makes it difficult to improve welding efficiency.

[0003] Second, it lacks dynamic attitude tracking capability. Existing devices cannot dynamically adjust the attitude of the weld joint in real time according to the changes in the direction of the weld in space during the welding process, making it difficult to ensure the consistency of welding quality across all sections of the weld.

[0004] Therefore, it is necessary to provide a variable-pitch automatic welding mechanism and its welding method. Summary of the Invention

[0005] The present invention provides a variable-pitch automatic welding mechanism and welding method, which effectively solves the problems of existing double-head welding devices being inconvenient to adjust the pitch and lacking dynamic posture following ability.

[0006] The technical solution adopted in this invention is: a variable-pitch automatic welding mechanism, including a linear module arranged along the X-axis direction, a first mounting plate fixedly arranged on the linear module, a second mounting plate driven by the linear module, a first rotary lifting welding assembly arranged on the first mounting plate, and a second rotary lifting welding assembly arranged on the second mounting plate. The first rotary lifting welding assembly and the second rotary lifting welding assembly can rotate and lift independently of each other. The linear module drives the second mounting plate to move the second rotary lifting welding assembly along the X-axis direction.

[0007] Furthermore, the No. 1 rotating lifting welding assembly and the No. 2 rotating lifting welding assembly have the same structure.

[0008] Furthermore, the first rotating lifting welding assembly includes a rotating platform mounted on the first mounting plate, a lifting assembly driven to rotate by the rotating platform, and a welding head driven to rise and fall by the lifting assembly.

[0009] Furthermore, the lifting assembly includes a bearing housing on a rotating platform, a ball bearing inside the bearing housing, a nut fixedly connected to the inner ring of the ball bearing, a lead screw threadedly connected to the nut, a first motor on the rotating platform, a drive pulley at the output end of the first motor, a driven pulley fixedly connected to the nut, and a synchronous belt drivingly connected to the drive pulley and the driven pulley. The welding head is fixedly located at the lower end of the lead screw.

[0010] Furthermore, a limit plate is also provided at the upper end of the lead screw.

[0011] Furthermore, the lead screw is a hollow lead screw.

[0012] Furthermore, the welding head includes a first block, a shaft clamp connecting the first block and the lead screw, and an ultrasonic welding head disposed at the lower end of the first block.

[0013] Furthermore, the No. 1 mounting plate is fixedly mounted at one end of the linear module.

[0014] The welding method, employing the aforementioned variable-pitch automatic welding mechanism, includes the following steps: S1, fixing the linear module to an external robotic arm via a mounting bracket, and having the external robotic arm move the entire variable-pitch automatic welding mechanism to the welding height of the automotive sheet metal parts; S2, selectively performing the following operations based on the number and location of the welds to be welded: If only a single weld seam needs to be welded, then one of the No. 1 rotating and lifting welding assembly and the No. 2 rotating and lifting welding assembly should be kept in standby and idle state, while the other should be moved above the weld seam. If two weld seams need to be welded simultaneously, the linear module drives the second mounting plate to move the second rotary lifting welding assembly along the X-axis, adjusting the horizontal distance between the first rotary lifting welding assembly and the second rotary lifting welding assembly until the two welding assemblies are aligned with the starting position of the two weld seams in the X direction; S3, start the first rotary welding assembly and / or the second rotary welding assembly to weld the corresponding weld seams on the automotive sheet metal parts.

[0015] Furthermore, during the welding process, the linear module drives the second mounting plate to move the second rotary lifting welding assembly along the X-axis to compensate for the trajectory change of the weld seam corresponding to the assembly in the X-axis direction; at the same time, the first rotary lifting welding assembly and the second rotary lifting welding assembly independently perform rotation and lifting actions according to the spatial orientation of their respective weld seams.

[0016] Beneficial effects of the invention: 1. The linear module drives the second mounting plate to move the second rotary lifting welding assembly along the X-axis, so that the horizontal distance between the two welding assemblies can be infinitely adjusted according to the actual span of the two welds on the same automotive sheet metal part, ensuring that the two welding assemblies are synchronously aligned after one positioning, without the need for repeated adjustments by an external robotic arm or welding in stages.

[0017] 2. The No. 1 rotating and lifting welding assembly and the No. 2 rotating and lifting welding assembly can rotate and lift independently of each other, so that the two welding assemblies can independently obtain the optimal welding tilt angle and weld height for their respective welds on different spatial orientations and heights on the automotive sheet metal parts, without interfering with each other.

[0018] 3. After one positioning, two welding components simultaneously weld two seams on the same automotive sheet metal part. The total welding time for a single part is reduced by about 50% compared to welding with a single welding head in multiple stages, which greatly improves production efficiency.

[0019] 4. The two welds are completed under the same robotic arm reference coordinate system and within the same heat-affected zone, resulting in a more uniform heat input distribution on the sheet metal parts. This effectively reduces the risk of local warping and uneven residual stress, ensuring that the welding strength and appearance quality of the two welds remain consistent. Attached Figure Description

[0020] Figure 1 A front view of a variable-pitch automatic welding mechanism provided for an embodiment of this application.

[0021] Figure 2 This is a schematic diagram of the first rotary lifting welding component of the variable-pitch automatic welding mechanism provided in the embodiments of this application.

[0022] The following are marked in the diagram: 1. Linear module; 2. Mounting plate No. 1; 3. Mounting plate No. 2; 4. Rotary lifting welding assembly No. 1; 5. Rotary lifting welding assembly No. 2; 41. Rotary platform; 42. Lifting assembly; 43. Welding head; 421. Lead screw; 422. Limiting plate; 431. Block No. 1; 423. Motor No. 1; 432. Shaft clamp; 433. Ultrasonic welding head. Detailed Implementation

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0024] like Figure 1 As shown, the first embodiment provided in this application is a variable-pitch automatic welding mechanism, the structure of which includes a linear module 1 arranged along the X-axis direction, a first mounting plate 2 fixedly arranged on the linear module 1, a second mounting plate 3 driven by the linear module 1, a first rotary lifting welding assembly 4 arranged on the first mounting plate 2, and a second rotary lifting welding assembly 5 arranged on the second mounting plate 3. The first rotary lifting welding assembly and the second rotary lifting welding assembly can rotate and lift independently of each other. The linear module 1 drives the second mounting plate 3 to move the second rotary lifting welding assembly 5 along the X-axis direction.

[0025] In actual use, the linear module 1 is fixed to the external robotic arm via a mounting bracket. When the external robotic arm moves the variable-pitch welding mechanism of this application to the working height, the linear module 1 drives the second rotary lifting welding component 5 to move relative to the first rotary lifting welding component 4, so that the first rotary lifting welding component 4 and the second rotary lifting welding component 5 reach above the corresponding weld seam according to the work requirements. The first rotary lifting welding component 4 and the second rotary lifting welding component 5 rotate and lift automatically and independently, so that the first rotary lifting component 42 and the second rotary lifting component 42 reach the working angle and height respectively to weld different weld seams.

[0026] In the above design, when simultaneously welding two welds on the same automotive sheet metal part, the linear module 1 drives the second mounting plate 3 to move the second rotary lifting welding assembly 5, so that the horizontal distance between the two welding assemblies adaptively matches the actual span of the two welds. Simultaneously, the first rotary lifting welding assembly 4 and the second rotary lifting welding assembly 5 rotate and lift independently, adapting to the different spatial postures of the two welds respectively. Therefore, the first rotary lifting welding assembly 4 and the second rotary lifting welding assembly 5 can simultaneously weld at their respective optimal angles and heights after a single positioning, which shortens the total welding time, makes the overall heat input of the sheet metal part more uniform, effectively reduces the risk of local warping, and ensures the consistency of the welding quality of the two welds.

[0027] Specifically: such as Figure 1 As shown, the No. 1 rotary lifting welding assembly 4 and the No. 2 rotary lifting welding assembly 5 have the same structure.

[0028] In actual use, because the mechanical structure, driving method, and control logic of the two welding components are completely identical, the same control algorithm and motion parameters of the control system can be applied to both components simultaneously. When welding is required at two different locations, the control system only needs to generate two independent but identical motion instruction sets and send them to the two components respectively. The two components can then synchronously execute their respective rotation and lifting actions, ensuring consistency in motion response speed and displacement accuracy between the two workstations.

[0029] In the above design, the use of No. 1 rotary lifting welding assembly 4 and No. 2 rotary lifting welding assembly 5 with identical structures significantly reduces the types and specifications of parts and components, reduces the number of spare parts, facilitates production assembly and subsequent maintenance, and effectively controls manufacturing costs. On the other hand, the unified structure ensures that the two workstations have completely identical kinematic characteristics and load-bearing capacity, which is conducive to the reuse and debugging of the control system software, avoids motion coordination errors caused by structural differences, and improves the synchronization of actions and the consistency of welding quality during parallel welding at two workstations.

[0030] Specifically: such as Figure 2 As shown, the first rotating lifting welding assembly 4 includes a rotating platform 41 mounted on the first mounting plate 2, a lifting assembly 42 driven to rotate by the rotating platform 41, and a welding head 43 driven to rise and fall by the lifting assembly 42.

[0031] In actual use, the rotating platform 41 serves as the basic drive source. After receiving angle commands from the control system, it drives its output end to rotate around the vertical axis. The lifting component 42, fixedly mounted on the rotating platform 41, rotates synchronously, thereby causing the welding head 43, connected to the movable end of the lifting component 42, to rotate in the horizontal plane to a preset circumferential angle. Based on this, the lifting component 42 independently activates its lifting drive function, pushing the welding head 43 up or down vertically until the working end face of the lower end of the welding head 43 reaches the preset welding height. The rotation and lifting actions of the welding head 43 are controlled by different drive sources and can be executed independently or simultaneously.

[0032] The above design enables flexible positioning of the welding head 43 in the polar coordinate system (height and angle), with clear structural hierarchy, short transmission chain, and fast response speed, allowing the welding head 43 to quickly and accurately reach the designated spatial position, effectively meeting the variable requirements of welding posture for complex curved surfaces or circumferential welds.

[0033] Specifically: such as Figure 2As shown, the lifting assembly 42 includes a bearing seat on the rotating platform 41, a ball bearing in the bearing seat, a nut fixedly connected to the inner ring of the ball bearing, a lead screw 421 threadedly connected to the nut, a first motor 423 on the rotating platform 41, a drive pulley at the output end of the first motor 423, a driven pulley fixedly connected to the nut, and a synchronous belt drivingly connected to the drive pulley and the driven pulley. The welding head 43 is fixedly installed at the lower end of the lead screw 421.

[0034] In actual use, when motor 423 is energized, it drives the drive pulley to rotate. The drive pulley transmits power to the driven pulley via a synchronous belt. Since the driven pulley is fixedly connected to the nut, and the nut is rotatably fitted to the bearing housing via a ball bearing, the driven pulley drives the nut to rotate in place within the bearing housing. When the nut rotates, its internal thread connects to the lead screw 421, converting the rotational motion into the linear motion of the lead screw 421 along the axial direction. This allows the lead screw 421 to drive the welding head 43 to achieve precise lifting and lowering displacement.

[0035] In the above design, the synchronous belt drive has the advantages of buffering and vibration absorption, smooth transmission, and low noise. It can absorb the impact load when the motor starts and stops, and ensure the smoothness of the lifting and lowering action. The ball bearing significantly reduces the frictional resistance when the nut rotates, and improves the transmission efficiency and the sensitivity of the lead screw 421 movement. The lead screw 421 nut pair (lead screw 421 and nut) has extremely high transmission accuracy and good self-locking performance, which can ensure that the welding head 43 can stay stably at any height position without slipping, thereby significantly improving the repeatability and stability of the welding point.

[0036] Specifically: such as Figure 2 As shown, a limit plate 422 is also provided at the upper end of the lead screw 421.

[0037] In actual use, during the operation of the lifting assembly 42, the lead screw 421 is driven by the nut to move upward or downward. When the lower end face of the limit plate 422 mates with the upper end face of the bearing seat, it also limits the downward limit position of the lead screw 421 (in accordance with the length design of the lead screw 421), thereby physically limiting the lifting stroke range of the welding head 43.

[0038] In the above design, by setting a limiting plate 422 at the upper end of the lead screw 421, a mechanical hard limit protection structure is formed, which avoids safety accidents caused by misoperation, such as the lead screw 421 overtraveling out of the nut or the welding head 43 colliding with the workpiece, and significantly improves the safety and reliability of equipment operation.

[0039] Specifically: the lead screw 421 is a hollow lead screw 421.

[0040] In the above design, the hollow lead screw 421 structure is adopted, which can effectively reduce the weight of the lead screw 421, thereby reducing the total mass of the moving part in the lifting assembly 42. This reduces the inertial load that the first motor 423 needs to overcome when driving the lead screw 421 to lift and lower, which not only reduces the driving power consumption of the first motor 423, but also improves the start and braking response speed of the lifting action, which is beneficial to extending the service life of the bearings of the rotating platform 41.

[0041] Specifically: such as Figure 2 As shown, the welding head 43 includes a first block 431, a shaft clamp 432 connecting the first block 431 and the lead screw 421, and an ultrasonic welding head 433 disposed at the lower end of the first block 431. The first block 431 is bolted to the shaft clamp 432.

[0042] In the above design, during operation, the lifting motion of the lead screw 421 is transmitted to the ultrasonic welding head 433 through the shaft clamp 432 and the first block 431, so that it reaches the predetermined height; at the same time, the ultrasonic welding head 433 receives the high-frequency electrical signal transmitted by the external ultrasonic generator, converts it into high-frequency mechanical vibration, and realizes ultrasonic welding.

[0043] In the above design, the screw rod 421 and the first block 431 are connected by the shaft clamp 432, which realizes a quick and firm connection between the shaft component and the block component. The shaft clamp 432 has a simple structure and is easy to install and disassemble, which facilitates the quick replacement and maintenance of the ultrasonic welding head 433 in the later stage.

[0044] Specifically, the first mounting plate 2 is fixedly installed at one end of the linear module 1.

[0045] In actual operation, the linear module 1 drives the second mounting plate 3 to move the second rotary lifting welding assembly 5. Meanwhile, the first mounting plate 2 is fixed to the end of the module, serving as a static reference point to keep the first rotary lifting welding assembly 4 stationary, thereby dynamically adjusting the distance between the second rotary lifting welding assembly 5 and the first rotary lifting welding assembly 4.

[0046] In the above design, the first mounting plate 2 is fixedly set at one end of the linear module 1, providing a clear zero point for the entire mechanism, which facilitates the calibration and zeroing operation of the welding start position. At the same time, this fixed setting ensures that the position of the first rotary lifting welding component 4 is absolutely fixed, while the second rotary lifting welding component 5 has the ability to move throughout its entire stroke. When adjusting the spacing, the single-sided movement of the second rotary lifting welding component 5 simplifies the drive control and synchronization algorithm compared to simultaneous movement on both sides, and can ensure that the absolute position of the welding head 43 on at least one side remains constant, which is beneficial for the external robotic arm to perform precise global positioning compensation based on the first welding head 43.

[0047] The second embodiment provided in this application is a welding method using the aforementioned variable-pitch automatic welding mechanism, comprising the following steps: S1, fixing the linear module 1 to an external robotic arm via a mounting bracket, and having the external robotic arm move the entire variable-pitch automatic welding mechanism to the welding operation height of the automotive sheet metal part; S2, selectively performing the following operations based on the number and location of the weld seams to be welded: If only a single weld seam needs to be welded, one of the No. 1 rotating and lifting welding assembly 4 and the No. 2 rotating and lifting welding assembly 5 is kept in standby and idle state, while the other is moved above the weld seam; if two weld seams need to be welded simultaneously, the linear module 1 drives the No. 2 mounting plate 3 to move the No. 2 rotating and lifting welding assembly 5 along the X-axis direction, adjusting the horizontal distance between the No. 1 rotating and lifting welding assembly 4 and the No. 2 rotating and lifting welding assembly 5 until the two welding assemblies are respectively aligned with the X-axis starting positions of the two weld seams; S3, start the No. 1 rotating welding assembly and / or the No. 2 rotating welding assembly to weld the corresponding weld seam on the automotive sheet metal part.

[0048] In the above design, single or double welding modes can be flexibly selected based on the actual number of welds to be welded on the automotive sheet metal parts. When only a single weld needs to be welded, only one rotary lifting welding component needs to be activated, while the other remains in standby mode, avoiding unnecessary energy consumption and welding head wear. When two welds need to be welded, the horizontal distance between the two rotary lifting welding components is adjusted via the linear module 1, allowing them to be aligned synchronously and welded simultaneously. This method integrates two operating modes into one mechanism, improving equipment utilization and reducing the energy cost per weld.

[0049] Specifically: During the welding process, the linear module 1 drives the second mounting plate 3 to move the second rotary lifting welding assembly 5 along the X-axis to compensate for the trajectory change of the weld seam corresponding to the assembly in the X-direction; at the same time, the first rotary lifting welding assembly 4 and the second rotary lifting welding assembly 5 independently perform rotation and lifting actions according to the spatial orientation of their respective weld seams.

[0050] In the above design, even if the weld seam on the automotive sheet metal part is a spatial curve rather than a straight line, the two welding heads 43 can still maintain the optimal posture during the moving welding process, ensuring that the welding quality of each segment of the entire weld seam is uniform and consistent, effectively avoiding defects such as incomplete welding or weld deviation caused by the inaccurate posture of the welding head due to changes in the weld seam trajectory.

[0051] In further detail, it should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A variable-pitch automatic welding mechanism, characterized in that: The system includes a linear module (1) arranged along the X-axis, a first mounting plate (2) fixedly mounted on the linear module (1), a second mounting plate (3) driven by the linear module (1), a first rotary lifting welding assembly (4) mounted on the first mounting plate (2), and a second rotary lifting welding assembly (5) mounted on the second mounting plate (3). The first rotary lifting welding assembly (4) and the second rotary lifting welding assembly (5) can rotate and lift independently of each other. The linear module (1) drives the second mounting plate (3) to move the second rotary lifting welding assembly (5) along the X-axis.

2. The variable-pitch automatic welding mechanism according to claim 1, characterized in that: The No. 1 rotary lifting welding assembly (4) and the No. 2 rotary lifting welding assembly (5) have the same structure.

3. The variable-pitch automatic welding mechanism according to claim 2, characterized in that: The first rotating lifting welding assembly (4) includes a rotating platform (41) set on the first mounting plate (2), a lifting assembly (42) driven to rotate by the rotating platform (41), and a welding head (43) driven to lift by the lifting assembly (42).

4. The variable-pitch automatic welding mechanism according to claim 3, characterized in that: The lifting assembly (42) includes a bearing seat on the rotating platform (41), a ball bearing in the bearing seat, a nut fixedly connected to the inner ring of the ball bearing, a screw (421) threadedly connected to the nut, a first motor (423) on the rotating platform (41), a drive pulley at the output end of the first motor (423), a driven pulley fixedly connected to the nut, and a synchronous belt that is connected to the drive pulley and the driven pulley for transmission. The welding head (43) is fixedly located at the lower end of the screw (421).

5. The variable-pitch automatic welding mechanism according to claim 3, characterized in that: The upper end of the lead screw (421) is also provided with a limit plate (422).

6. The variable-pitch automatic welding mechanism according to claim 3, characterized in that: The lead screw (421) is a hollow lead screw (421).

7. The variable-pitch automatic welding mechanism according to claim 3, characterized in that: The welding head (43) includes a first block (431), a shaft clamp (432) connecting the first block (431) and the lead screw (421), and an ultrasonic welding head (433) located at the lower end of the first block (431).

8. The variable-pitch automatic welding mechanism according to claim 1, characterized in that: The first mounting plate (2) is fixedly installed at one end of the linear module (1).

9. A welding method employing the variable-pitch automatic welding mechanism as described in any one of claims 1 to 8, characterized in that: Includes the following steps: S1. The linear module (1) is fixed to the external robotic arm via a mounting bracket, and the external robotic arm drives the entire variable-pitch automatic welding mechanism to the welding height of the automotive sheet metal parts; S2. Based on the number and location of the welds to be welded, the following operations are selectively performed: If only a single weld seam needs to be welded, then one of the No. 1 rotating lifting welding assembly (4) and the No. 2 rotating lifting welding assembly (5) should be kept in standby idle state, while the other is moved above the weld seam. If two weld seams need to be welded simultaneously, the linear module (1) drives the second mounting plate (3) to move the second rotary lifting welding assembly (5) along the X-axis direction, and adjusts the horizontal distance between the first rotary lifting welding assembly (4) and the second rotary lifting welding assembly (5) until the two welding assemblies are aligned with the X-axis starting positions of the two weld seams respectively; S3, start the first rotary welding assembly and / or the second rotary welding assembly to weld the corresponding weld seams on the automotive sheet metal parts.

10. The welding method according to claim 9, characterized in that: During the welding process, the linear module (1) drives the second mounting plate (3) to move the second rotary lifting welding assembly (5) along the X-axis to compensate for the trajectory change of the weld seam corresponding to the assembly in the X direction; at the same time, the first rotary lifting welding assembly (4) and the second rotary lifting welding assembly (5) rotate and lift independently according to the spatial orientation of their respective weld seams.

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