Alignment and clamping tooling for automatic assembly welding of vehicle door ring, and weld seam alignment method therefor

Abstract

The present invention relates to an alignment and clamping tooling for automatic assembly welding of a vehicle door ring, and a weld seam alignment method therefor. The alignment and clamping tooling for automatic assembly welding of a vehicle door ring comprises a gripper unit and a clamp unit, wherein the gripper unit is connected to a working end of a robotic arm, the gripper unit comprises a gripper frame, and a plurality of vision camera mechanisms and a plurality of suction cup mechanisms are respectively mounted on the bottom of the gripper frame in a matching manner; and the clamp unit comprises a clamp base, a plurality of first alignment mechanisms are mounted on the top of the clamp base in an matching manner, the first alignment mechanisms are used for clamping workpieces, a light source is provided inside each individual first alignment mechanism, and the light source illuminates a workpiece from the back surface of the workpiece, enabling each vision camera mechanism to locate a weld seam on the corresponding workpiece. The alignment and clamping tooling has high operational flexibility, and can achieve flexible and automatic alignment and assembly of weld seams, has high equipment stability and high operation continuity, and also achieves high alignment precision and good assembly quality.

Description

Automatic welding and alignment fixture for automotive door rings and its weld alignment method Technical Field

[0001] This invention relates to the field of automobile manufacturing technology, and in particular to an alignment clamping fixture for automatic welding of automobile door rings and a method for aligning the weld seams. Background Technology

[0002] Automotive door rings are made by assembling and welding several door ring plates. Before laser welding, the door ring plates need to be positioned correctly so that they can be automatically welded by a laser welding machine. The positional accuracy of the door ring plates before welding directly affects the welding quality of the subsequent automotive door rings.

[0003] In related technologies, Chinese patent CN114713983A discloses an automatic assembly fixture and operation method for laser-welded steel plates for automotive door rings. By setting up a vision camera mechanism and a welding drive mechanism, the weld between two adjacent steel plates can be adjusted. After the adjustment is in place, the steel plates are positioned by using an electromagnet assembly assembly, thereby ensuring the welding quality of the door ring.

[0004] However, the aforementioned automatic assembly fixture for laser-welded steel plates for automotive door rings has the following problems:

[0005] (1) All the mechanisms and components in the above-mentioned automatic assembly fixture are fixed on the base plate, which results in the components being placed too tightly. When assembling door rings with more than 4 welds, the steel plates cannot be placed, making it difficult to apply to the assembly of all door ring types.

[0006] (2) For the vision camera mechanism in the above-mentioned automatic assembly fixture, the vision camera is fixed on the rotary drive device and the rotary drive device is fixed on the lifting drive device. That is, the vision camera adopts the cantilever support method. The longer the cantilever, the lower the fixed position accuracy, which makes the repeatability of the vision camera unable to reach 0.02mm, ultimately resulting in a decrease in the quality of the door ring assembly and a low yield. At the same time, the rotary drive device and the lifting drive device have complex structures and high failure rates, resulting in poor equipment operation continuity.

[0007] (3) When the above-mentioned automatic assembly fixture aligns the steel plate, it is usually necessary to set up an auxiliary light source next to the camera for lighting. The vision camera component in the vision camera mechanism is equipped with an integrated light source that projects light onto the steel plate. However, the surface of the steel plate used to make the door ring is usually covered with various coatings, and the reflectivity varies. Projecting light onto the steel plate causes the edge line to become blurred. At this time, it is necessary to frequently adjust the exposure parameters of the vision camera component, which is cumbersome and also leads to a decrease in the assembly quality.

[0008] In summary, the automatic assembly fixture described above uses a mechanical pushing method to align the steel plates before welding. Because the outer contours of each individual closed-loop welded component, such as the door ring, vary slightly, the tolerances accumulate to the last seam when assembled into a closed door ring, resulting in a gap at one end of the last seam and ultimately failing to meet welding process requirements. Furthermore, the automatic assembly fixture suffers from low repeatability of the rotary and lifting drive devices, failing to meet the requirement of a steel plate positioning accuracy of less than ±0.05mm. This forces the steel plates closer together, again resulting in a gap at one end of the last seam. Technical issues

[0009] In response to the shortcomings of the existing production technology, the applicant provides an alignment clamping fixture for automatic welding of automotive door rings and its weld alignment method. It is highly flexible in use, can realize flexible automatic alignment and assembly of welds, has high equipment stability and high equipment operation continuity; at the same time, it has high alignment accuracy and good assembly quality. Technical solutions

[0010] The technical solution adopted in this invention is as follows:

[0011] An alignment and clamping fixture for automatic welding of automotive door rings includes a gripper unit and a clamping unit, wherein the gripper unit is connected to the working end of a robotic arm.

[0012] The gripper unit includes a gripper frame, and several vision camera mechanisms and several suction cup mechanisms are respectively installed at the bottom of the gripper frame. The gripper unit takes pictures of the weld seam on the workpiece through the vision camera mechanisms, and the gripper unit picks up the workpiece through the suction cup mechanisms, thereby transporting the workpiece to the target working position of the clamping unit by the robotic arm.

[0013] The fixture unit includes a fixture base, and several first alignment mechanisms are fitted on the top of the fixture base. The first alignment mechanisms are used to clamp the workpiece. Each first alignment mechanism is equipped with a light source, which is arranged below the workpiece. The light source illuminates the workpiece from the back of the workpiece, thereby enabling the vision camera mechanism to locate the weld seam on the workpiece.

[0014] As a further improvement to the above technical solution:

[0015] The structure of a single first alignment mechanism is as follows: it includes a first mounting base, on which at least one first switching magnetic seat is fixed. The first alignment mechanism is quickly connected to the clamp base through the first switching magnetic seat. A connecting seat is fixed on the top of the first mounting base, and a telescopic cylinder is fixed on the connecting seat. The output end of the telescopic cylinder is connected to a light source. A seat plate is fixed on the top of the connecting seat. A strip-shaped through hole is opened on the end face of the seat plate. Several electromagnets are installed at intervals on the top of the seat plate. A light-transmitting gap is formed between two adjacent electromagnets. The light-transmitting gap is arranged corresponding to the strip-shaped through hole.

[0016] The telescopic cylinder drives the light source to move in a straight line, so that the light source illuminates the workpiece from the back through the light-transmitting gap.

[0017] The structure of a single first alignment mechanism is as follows: it includes a first mounting base, on which at least one first switching magnetic seat is fixed. The first alignment mechanism is quickly connected to the clamp base through the first switching magnetic seat. A connecting seat is fixed on the top of the first mounting base, and a telescopic cylinder is fixed on the connecting seat. The output end of the telescopic cylinder is connected to a light source. A seat plate is fixed on the top of the connecting seat. A strip-shaped through hole is opened on the end face of the seat plate. Several electromagnets are installed at intervals on the top of the seat plate. A light-transmitting gap is formed between two adjacent electromagnets. The light-transmitting gap is arranged corresponding to the strip-shaped through hole.

[0018] The telescopic cylinder drives the light source to move in a straight line, so that the light source illuminates the workpiece from the back through the light-transmitting gap.

[0019] The bottom of the gripper frame is fixed with a fixing plate group, which includes several first fixing plates and several second fixing plates. Each first fixing plate and each second fixing plate is equipped with at least one suction cup mechanism.

[0020] For each single first fixed plate, at least one vision camera mechanism is also installed, as well as a finger pressing mechanism arranged in a one-to-one correspondence with the vision camera mechanism.

[0021] The structure of a single vision camera mechanism is as follows: it includes a camera mounting plate, on which a vision camera is fixed. Several first quick-locking devices are arranged on the camera mounting plate around the vision camera. The vision camera mechanism is quickly connected to the first fixed plate through the first quick-locking devices. The end face of the camera mounting plate is provided with a first fixing pin hole and a second fixing pin hole, and the vision camera mechanism is positioned on the first fixed plate through the first fixing pin hole and the second fixing pin hole.

[0022] The structure of a single finger pressing mechanism is as follows: it includes a finger pressing mounting base, on which several second quick-locking devices are fixed. The finger pressing mechanism is quickly connected to the first fixed plate through the second quick-locking devices. Several finger pressing cylinders are fixed at the bottom of the finger pressing mounting base, and the output end of a single finger pressing cylinder is connected to a universal ball joint screw.

[0023] The pressure finger cylinder drives the corresponding universal ball screw to extend, so that the universal ball of the corresponding universal ball screw abuts against the workpiece.

[0024] The structure of a single suction cup mechanism is as follows: it includes a suction cup mounting base, which is installed in conjunction with a fixed plate assembly via a rotating plunger; a suction cup is installed at the bottom of the suction cup mounting base via a spring rod; and a suction cup air pipe connector for connecting to an external air source is installed at the top of the suction cup mounting base. The external air source drives the suction cup to pick up the workpiece through the suction cup air pipe connector.

[0025] The gripper unit is installed in conjunction with the working end of the robotic arm through a gripper quick-change mechanism. The structure of the gripper quick-change mechanism is as follows: it includes a quick-change mounting plate, and the top end face of the quick-change mounting plate is provided with a flat quick-change mounting surface. The gripper quick-change mechanism is connected to the working end of the robotic arm through the quick-change mounting surface.

[0026] The bottom of the quick-change mounting plate is fitted with several quick-change locking devices and several quick-change positioning pins. The gripper quick-change mechanism is locked to the gripper frame through the quick-change locking devices.

[0027] The top of the fixture base is fixed with a positioning fixture, which is used to position the first alignment mechanism. The positioning fixture includes a mounting bracket, and the top of the mounting bracket is fixed with a positioning plate. The edge of the positioning plate is provided with several spaced positioning angles, which correspond one-to-one with the first alignment mechanism.

[0028] The top of the fixture base is also equipped with several support mechanisms for supporting the workpiece. The structure of a single support mechanism is as follows: it includes a second mounting base, at least one second switching magnetic seat is fixed to the bottom of the second mounting base, the support mechanism is quickly connected to the fixture base through the second switching magnetic seat, and several support columns are fixed to the top of the second mounting base. Nylon plates are also installed on the top of the support columns.

[0029] A weld alignment method based on the above-mentioned automatic welding fixture for automotive door rings includes the following steps:

[0030] Step 1: Preparation, using a robot to pre-position the various steel plates in the workpiece;

[0031] Step 2: The robotic arm moves the gripper unit to the top of the placed workpiece. The gripper unit uses a suction cup mechanism to hold the placed workpiece, and then the robotic arm moves the workpiece through the gripper unit.

[0032] When each weld seam on the workpiece corresponds to the light-transmitting gap in each of the first alignment mechanisms, it indicates that the robotic arm has moved the workpiece to the target working position of the fixture unit, and then the suction cup mechanism releases the workpiece.

[0033] Step 3: The robotic arm drives the gripper unit to lift to a certain height, so that the distance between the vision camera lens in the vision camera mechanism and the upper surface of the workpiece is equal to the focal length of the vision camera. Then, each pressing finger cylinder in the pressing finger mechanism extends at the same time, driving the corresponding universal ball screw to press against the upper surface of the workpiece.

[0034] Step 4: The telescopic cylinders in each of the first alignment mechanisms extend simultaneously, driving the corresponding light source to move to face the light transmission gap, so that the light source illuminates the corresponding weld.

[0035] Step 5: Take photos of both ends of each weld seam using a vision camera and transmit the photo data to the industrial control computer. The industrial control computer calculates the gap of each weld seam based on the photo data and calculates the difference between the gaps of different weld seams.

[0036] Based on the gaps of each weld, the differences between different weld gaps, and the welding requirements, the industrial control computer calculates the target positions of each steel plate in the workpiece.

[0037] Step 6: The second alignment mechanism adjusts each steel plate in the workpiece to the target position. Then, the vision camera takes photos of the two ends of each weld seam again. The industrial control computer judges whether the weld seam in the workpiece is aligned based on the photo data taken by the vision camera again.

[0038] When the alignment of each weld seam in the workpiece is completed, each pressing finger mechanism releases the workpiece, and the light source in each first alignment mechanism retracts to the initial position.

[0039] If the weld seams in the workpiece are not aligned, repeat steps five and six until the weld seams in the workpiece are aligned. Beneficial effects

[0040] The beneficial effects of this invention are as follows:

[0041] The alignment and clamping fixture for automatic welding of automotive door rings of the present invention has a compact and reasonable structure and is easy to operate. By setting up gripper units, the unique position of each mechanism can be guaranteed, increasing the overall working stability of the equipment and improving the positioning accuracy of the vision camera. For different door ring types, the corresponding gripper units can be quickly and directly replaced through the gripper quick-release mechanism, which facilitates layout, reduces design difficulty, simplifies the focusing operation of the vision camera, and improves work efficiency.

[0042] The automatic welding and alignment clamping fixture for automotive door rings of the present invention features a unique arrangement of the gripper frame and fixing plate assembly on the gripper frame within the gripper unit. This arrangement improves the accuracy and stability of the vision camera, resulting in a stable and reliable structure with a low failure rate, effectively enhancing the repeatability of the vision camera. Furthermore, the vision camera mechanism, pressing finger mechanism, and suction cup mechanism within the gripper unit are versatile and highly interchangeable. When processing door rings of other types, only the gripper frame and fixing plate assembly need to be replaced; the vision camera mechanism, pressing finger mechanism, and suction cup mechanism can be reused, thereby reducing production costs.

[0043] The alignment and clamping fixture for automatic welding of automotive door rings of the present invention can be quickly disassembled and assembled by the vision camera mechanism, the pressing finger mechanism, the suction cup mechanism, the first alignment mechanism and the support mechanism, and can achieve flexible switching for different door ring models. It has high flexibility and good compatibility.

[0044] The automatic welding and alignment fixture for automotive door rings of this invention features a vision camera with a resolution of at least 20 megapixels. By illuminating the workpiece from the back using the light source in the first alignment mechanism, the influence of the workpiece coating on the vision camera can be avoided, ensuring that workpieces with any coating have distinct edges. This achieves a recognition accuracy of 0.02mm for the vision camera. In conjunction with the second alignment mechanism, the positioning accuracy of each steel plate in the workpiece can reach ≤±0.05mm. Ultimately, the tolerance between weld seams in the workpiece is evenly distributed across each weld seam, ensuring that the gap tolerance between each weld seam is kept within 0.1mm, thus meeting the high-precision welding process requirements.

[0045] The weld alignment method of the present invention, by setting up a vision camera mechanism and an industrial control computer, can calculate the target position of each steel plate in the workpiece, thereby evenly distributing the deviation between different welds to each weld, reducing the requirements of high-quality door rings on sheet metal, improving yield, and improving welding accuracy; at the same time, by detecting the gap of the weld through the vision camera mechanism, it can prevent defective products from flowing into the welding process, avoid wasting sheet metal, and improve yield. Attached Figure Description

[0046] Figure 1 is a schematic diagram of the structure of the present invention.

[0047] Figure 2 is a top view of Figure 1.

[0048] Figure 3 is a schematic diagram of the quick-change mechanism for the gripper in this invention.

[0049] Figure 4 is a schematic diagram of the gripper unit in this invention (the gripper quick-change mechanism is omitted).

[0050] Figure 5 is a schematic diagram of the installation structure of the fixed plate assembly in this invention.

[0051] Figure 6 is a schematic diagram of the visual camera mechanism in this invention.

[0052] Figure 7 is a schematic diagram of the pressure finger mechanism in this invention.

[0053] Figure 8 is a schematic diagram of the suction cup mechanism in this invention.

[0054] Figure 9 is a schematic diagram of the fixture unit in this invention.

[0055] Figure 10 is a schematic diagram of the structure of the first alignment mechanism in this invention.

[0056] Figure 11 is an exploded view of the first alignment mechanism in this invention.

[0057] Figure 12 is a schematic diagram of the second alignment mechanism in this invention.

[0058] Figure 13 is a schematic diagram of the positioning fixture in this invention.

[0059] Figure 14 is a schematic diagram of the support mechanism in this invention.

[0060] Figure 15 is a schematic diagram of the workpiece structure in this invention.

[0061] The components include: 1. quick-change gripper mechanism; 2. gripper frame; 3. vision camera mechanism; 4. fixing plate assembly; 5. pressing finger mechanism; 6. suction cup mechanism; 7. clamp base; 8. first alignment mechanism; 9. second alignment mechanism; 10. positioning fixture; 11. support mechanism; 12. workpiece; 13. gripper pin sleeve; 14. gripper locking pin.

[0062] 101. Quick-change mounting plate; 102. Quick-change mounting surface; 103. Quick-change locating pin; 104. Quick-change locking device;

[0063] 301. Camera mounting plate; 302. Vision camera; 303. First quick-locking device; 304. Protective cover; 305. First fixing pin hole; 306. Second fixing pin hole;

[0064] 501. Finger pressing mounting base; 502. Finger pressing cylinder; 503. Universal ball joint screw; 504. Finger pressing air pipe connector; 505. Second quick locking device;

[0065] 601. Suction cup mounting base; 602. Suction cup; 603. Spring rod; 604. Suction cup air pipe connector; 605. Rotary plunger;

[0066] 801. First mounting base; 802. First switching magnetic base; 803. Light source; 804. Connecting base; 805. Telescopic cylinder; 806. Electromagnet; 807. Base plate; 808. Limiting plate; 809. Light transmission gap; 810. V-groove; 811. Positioning surface;

[0067] 901. Pneumatic magnetic chuck; 902. Chuck mounting plate; 903. First driving device; 904. Second driving device; 905. Rotating device;

[0068] 1001. Positioning plate; 1002. Mounting bracket; 1003. Positioning angle;

[0069] 1101. Second mounting base; 1102. Second switch magnetic base; 1103. Support column; 1104. Nylon plate. The best embodiment of the present invention

[0070] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0071] The structure and function of this invention are as follows:

[0072] As shown in Figures 1-15, the alignment and clamping fixture for automatic welding of automotive door rings in this embodiment includes a gripper unit and a clamping unit. The gripper unit is connected to the working end of the robotic arm. The gripper unit includes a gripper frame 2, and several vision camera mechanisms 3 and several suction cup mechanisms 6 are respectively installed at the bottom of the gripper frame 2. The gripper unit takes pictures of the weld seam on the workpiece 12 through the vision camera mechanism 3, and the gripper unit picks up the workpiece 12 through the suction cup mechanism 6, thereby transporting the workpiece 12 to the target working position of the clamping unit by the robotic arm. The clamping unit includes a clamping base 7, and several first alignment mechanisms 8 are installed on the top of the clamping base 7. The first alignment mechanisms 8 are used to clamp the workpiece 12. A light source 803 is provided in each first alignment mechanism 8. The light source 803 is arranged below the workpiece 12 and illuminates the workpiece 12 from the back of the workpiece 12, thereby enabling the vision camera mechanism 3 to locate the weld seam on the workpiece 12.

[0073] The alignment and clamping fixture for automatic welding of automotive door rings in this embodiment includes a gripper unit and a clamping unit. The gripper unit includes a gripper quick-change mechanism 1, a gripper frame 2, a vision camera mechanism 3, a fixing plate group 4, a pressing finger mechanism 5, and a suction cup mechanism 6. The clamping unit includes a clamping base 7, a first alignment mechanism 8, a second alignment mechanism 9, a positioning fixture 10, and a support mechanism 11.

[0074] As shown in Figures 1-2 and 4, the gripper frame 2 is the overall mounting frame of the gripper unit. It is installed in conjunction with the vision camera mechanism 3, the pressure finger mechanism 5, and the suction cup mechanism 6 through the fixing plate group 4. In addition, the top of the gripper unit 1 is provided with several gripper pin sleeves 13 and several gripper locking pins 14. The gripper pin sleeves 13 and gripper locking pins 14 are used to cooperate with the gripper quick change mechanism 1 for installation.

[0075] As shown in Figure 15, in this embodiment, workpiece 12 is a car door ring of different types, which is made by splicing together multiple steel plates.

[0076] The gripper unit is installed in conjunction with the working end of the robotic arm via the gripper quick-change mechanism 1, as shown in Figures 2 and 3. The structure of the gripper quick-change mechanism 1 is as follows: it includes a quick-change mounting plate 101, the top end face of which is provided with a flat quick-change mounting surface 102, and the gripper quick-change mechanism 1 is connected to the working end of the robotic arm through the quick-change mounting surface 102; several quick-change locking devices 104 and several quick-change positioning pins 103 are installed at the bottom of the quick-change mounting plate 101, and the gripper quick-change mechanism 1 is locked to the gripper frame 2 through the quick-change locking devices 104. The quick-change gripper mechanism 1 achieves a reliable connection between the gripper unit and the working end of the robotic arm via the quick-change mounting surface 102. In the quick-change mechanism 1, the quick-change locking device 104 corresponds one-to-one with the gripper locking pin 14 on the gripper frame 2, and the quick-change positioning pin 103 corresponds one-to-one with the gripper pin sleeve 13. The quick-change locking device 104 is connected to the corresponding gripper locking pin 14 via an electrical control switch, thereby achieving a quick-release connection between the robotic arm and the gripper frame 2. The quick-change positioning pin 103 and the gripper pin sleeve 13 fit tightly together, preventing displacement or movement of the gripper frame 2 during the movement of the gripper unit by the robotic arm, and ensuring a reliable connection between the gripper unit and the robotic arm after repeated replacements. By setting up the quick-change gripper mechanism 1, it is possible to quickly replace the entire gripper unit on the robotic arm when dealing with different types of door rings, improving replacement efficiency.

[0077] In this embodiment, the robotic arm is used to drive the gripper unit to perform actions, including but not limited to multi-axis articulated robots and gantry manipulators.

[0078] As shown in Figures 1-2 and 4-5, a fixing plate assembly 4 is fixed to the bottom of the gripper frame 2. The fixing plate assembly 4 includes several first fixing plates and several second fixing plates. At least one suction cup mechanism 6 is installed on each first fixing plate and each second fixing plate. For each single first fixing plate, at least one vision camera mechanism 3 is also installed, as well as a finger pressing mechanism 5 arranged one-to-one with the vision camera mechanism 3. That is, as shown in Figure 4, the vision camera mechanism 3 is installed with the gripper frame 2 through the first fixing plate 401, the finger pressing mechanism 2 is installed with the gripper frame 2 through the first fixing plate 401, and the suction cup mechanism 6 is installed through the first fixing plate 401 and the second fixing plate 402.

[0079] The position of the first fixing plate 401 on the gripper frame 2 is determined according to the position of the weld on the workpiece 12, and the position of the second fixing plate 402 on the gripper frame 2 is determined according to the overall shape of the workpiece 12.

[0080] In addition, to facilitate the installation of the visual camera mechanism 3, several camera fixing pins are provided on the first fixing plate 401.

[0081] As shown in Figure 6, the structure of a single vision camera mechanism 3 is as follows: it includes a camera mounting plate 301, on which a vision camera 302 is fixed. Several first quick-locking devices 303 are arranged on the camera mounting plate 301 around the vision camera 302. The vision camera mechanism 3 is quickly connected to the first fixed plate through the first quick-locking devices 303. The end face of the camera mounting plate 301 is provided with a first fixing pin hole 305 and a second fixing pin hole 306 respectively. The vision camera mechanism 3 is positioned on the first fixed plate through the first fixing pin hole 305 and the second fixing pin hole 306. The vision camera 302 is fixed to the camera mounting plate 301 with screws. In this embodiment, the vision camera 302 has a pixel count of not less than 20 million. A silicone protective cover 304 is also installed on the outside of the vision camera 302 to protect it. The first quick-locking device 303 is manual. By manually pressing the button on the upper end of the first quick-locking device 303, the vision camera mechanism 3 can be quickly disassembled and assembled from the first fixing plate 401. In this embodiment, the first fixing pin hole 305 is a round hole and the second fixing pin hole 306 is an elliptical hole. The first fixing pin hole 305 and the second fixing pin hole 306 respectively cooperate with the two camera fixing pins on the first fixing plate 401, which can repeatedly and accurately position the vision camera mechanism 3, thereby improving the subsequent welding accuracy.

[0082] Each vision camera mechanism 3 is equipped with a finger pressing mechanism 5 on one side. The distribution principle of the finger pressing mechanism 5 and the corresponding vision camera mechanism 3 is that they are located at the head and tail ends of the weld seam on the workpiece 12. That is, each weld seam on the workpiece 12 is equipped with two vision camera mechanisms 3 and two finger pressing mechanisms 5.

[0083] The pressing mechanism 5 is used to hold the workpiece 12 in place to prevent the corners of the workpiece 12 from lifting up when the vision camera 302 takes pictures, thus affecting the picture results and ensuring the accuracy of the picture.

[0084] As shown in Figure 7, the structure of a single pressing finger mechanism 5 is as follows: it includes a pressing finger mounting base 501, on which several second quick-locking devices 505 are fixed. The pressing finger mechanism 5 is quickly connected to the first fixed plate through the second quick-locking devices 505. Several pressing finger cylinders 502 are fixed at the bottom of the pressing finger mounting base 501. The output end of a single pressing finger cylinder 502 is connected to a universal ball screw 503. The pressing finger cylinder 502 drives the corresponding universal ball screw 503 to extend, so that the universal ball of the corresponding universal ball screw 503 abuts against the workpiece 12. In this embodiment, the finger-pressing cylinder 502 is a single-acting cylinder used to drive the universal ball screw 503 to move linearly. The top of the finger-pressing mounting base 501 is fitted with a finger-pressing air pipe connector 504 for supplying air to the finger-pressing cylinder 502. The working end of the universal ball screw 503 is provided with a universal ball. The universal ball screw 503 contacts the workpiece 12 through the universal ball, which can reduce the movement resistance of the workpiece 12 during the subsequent weld alignment process. The second quick-locking device 505 is also manually operated and is used for quick disassembly and assembly of the finger-pressing mechanism 5 from the first fixed plate 401.

[0085] The suction cup mechanism 6 is used to adsorb the workpiece 12. As shown in Figure 8, the structure of a single suction cup mechanism 6 is as follows: it includes a suction cup mounting base 601, which is installed in conjunction with the fixed plate assembly 4 via a rotating plunger 605. The bottom of the suction cup mounting base 601 is fitted with a suction cup 602 via a spring rod 603, and the top of the suction cup mounting base 601 is fitted with a suction cup air pipe connector 604 for connecting to an external air source. The external air source drives the suction cup 602 to pick up the workpiece 12 through the suction cup air pipe connector 604. The spring rod 603 acts as a buffer when the suction cup 602 contacts the workpiece 12; the rotating plunger 605 is used to cooperate with the fixed plate assembly 4, enabling quick assembly and disassembly between the suction cup mechanism 6 and the fixed plate assembly 4; and the suction cup air pipe connector 604 is used to supply air to the suction cup 602.

[0086] In this embodiment, each gripper unit is designed for a specific type of door ring. When the alignment and clamping fixture processes door rings of different types, the gripper quick-change unit 1 can quickly change the gripper unit (including gripper frame 2, vision camera mechanism 3, fixed plate group 4, pressing finger mechanism 5, suction cup mechanism 6) at the working end of the robotic arm to match the door ring type and improve welding accuracy.

[0087] As shown in Figure 9, the fixture base 7 is the mounting carrier for the entire gripper unit. It is fixed on the bracket or cooperates with the movable slide. The first alignment mechanism 8, the second alignment mechanism 9, the positioning fixture 10, and the support mechanism 11 are all installed on the top of the fixture base 7.

[0088] As shown in Figures 10 and 11, the structure of a single first alignment mechanism 8 is as follows: it includes a first mounting base 801, on which at least one first switching magnetic base 802 is fixed. The first alignment mechanism 8 is quickly connected to the fixture base 7 via the first switching magnetic base 802. A connecting seat 804 is fixed to the top of the first mounting base 801, and a telescopic cylinder 805 is fixed to the connecting seat 804. The output end of the telescopic cylinder 805 is connected to a light source 803. A seat plate 807 is fixed to the top of the connecting seat 804. A strip-shaped through hole is opened on the end face of the seat plate 807. Several electromagnets 806 are installed at intervals on the top of the seat plate 807. A light-transmitting gap 809 is formed between two adjacent electromagnets 806. The light-transmitting gap 809 is arranged corresponding to the strip-shaped through hole. The telescopic cylinder 805 drives the light source 803 to move linearly, so that the light source 803 illuminates the workpiece 12 from the back of the workpiece 12 through the light-transmitting gap 809. The first alignment mechanism 8 is used to support the workpiece 12 and can polish the weld seam during alignment. In addition, after the weld seam alignment is completed, the workpiece 12 can be attracted by the electromagnet 806 and fixed.

[0089] The first alignment mechanism 8 achieves quick assembly and disassembly with the fixture base 7 via the first switching magnetic base 802. The first switching magnetic base 802 is a manual knob type. When the first alignment mechanism 8 is working normally, the first switching magnetic base 802 is attracted and fixed to the top of the fixture base 7. When the door ring plate type is changed, it is necessary to move the position of the first alignment mechanism 8. At this time, manually rotate the knob on the first switching magnetic base 802 to demagnetize it. After moving it to the new position, manually rotate the knob again to make it re-attach to the fixture base 7.

[0090] Electromagnet 806 is fixed on base plate 807. Two electromagnets 806 are arranged at intervals to form a light-transmitting gap 809 between the two electromagnets. The width of the light-transmitting gap 809 is 10mm-16mm. The two electromagnets 806 are connected and limited by a limiting plate 808. The top of the limiting plate 808 is provided with a V-groove 810. The two electromagnets 806 are positioned by the V-groove 810 to ensure the width of the light-transmitting gap 809.

[0091] One of the electromagnets 806 has two adjacent outer side walls forming a positioning surface 811. The positioning surface 811 corresponds to the positioning angle 1003 in the positioning fixture 10, so that the installation position of the first alignment mechanism 8 on the fixture base 7 can be determined by the positioning fixture 10.

[0092] The two electromagnets 806 in the first alignment mechanism 8 respectively attract or support the welding edges of the two steel plates in the workpiece 12, so that the splicing weld of the two steel plates falls between the light transmission gaps 809.

[0093] The telescopic cylinder 805 drives the light source 803 to move to the light transmission gap 809, so as to illuminate from below the workpiece 12. When illuminating is not needed, the telescopic cylinder 805 retracts, so that the light source 803 moves away from the light transmission gap 809, preventing welding slag from splashing from the light transmission gap 809 and damaging the light source 803 during subsequent welding.

[0094] The light source 803 is elongated and used to illuminate the workpiece 12 from bottom to top. At this time, the background and weld are bright and the workpiece 12 is dark, which can improve the camera's capture accuracy and thus improve the weld alignment accuracy.

[0095] In this embodiment, several second alignment mechanisms 9 are also installed on the top of the fixture base 7. The second alignment mechanisms 9 are used to fine-tune the position of each steel plate in the workpiece 12 to perform weld alignment and uniformity. As shown in Figure 12, a single second alignment mechanism 9 includes a first driving device 903. The working end of the first driving device 903 is connected to a second driving device 904. The working end of the second driving device 904 is connected to a rotating device 905. The working end of the rotating device 905 is connected to a suction cup mounting plate 902. Several pneumatic magnetic suction cups 901 are fixed on the top of the suction cup mounting plate 902. The pneumatic magnetic suction cups 901 are used to adsorb the end face of the corresponding steel plate in the workpiece 12. Driven by the first driving device 903, they move linearly in the horizontal X direction. Driven by the second driving device 904, they move linearly in the horizontal Y direction. Driven by the rotating device 905, they rotate in the circumferential direction, thereby adjusting the position of the steel plate.

[0096] In the second alignment mechanism 9, both the first drive device 903 and the second drive device 904 adopt a structure of drive components combined with sliders and slide rails. The drive components can be cylinders or motors. When the drive components are rotary motors, they can be equipped with lead screw feed mechanisms for transmission.

[0097] The rotating device 905 adopts a structure in which a motor is used in conjunction with a slewing bearing.

[0098] A positioning fixture 10 is fixed to the top of the fixture base 7, as shown in Figure 13. The positioning fixture 10 is used to position the arrangement of the first alignment mechanism 8. The positioning fixture 10 includes a mounting bracket 1002, and a positioning plate 1001 is fixed to the top of the mounting bracket 1002. Several positioning angles 1003 are spaced apart on the edge of the positioning plate 1001, and the positioning angles 1003 correspond one-to-one with the first alignment mechanism 8. Since the light-transmitting gap 809 in the first alignment mechanism 8 needs to correspond one-to-one with the weld seam on the workpiece 12, different shapes of positioning plates 1001 are used for different types of door rings to flexibly adjust the arrangement of the first alignment mechanism 8 on the fixture base 7.

[0099] The top of the fixture base 7 is also fitted with several support mechanisms 11 for supporting the workpiece 12, as shown in Figure 14. The structure of a single support mechanism 11 is as follows: it includes a second mounting base 1101, at least one second switching magnetic base 1102 fixed to the bottom of the second mounting base 1101, and the support mechanism 11 is quickly connected to the fixture base 7 via the second switching magnetic base 1102. Several support columns 1103 are fixed to the top of the second mounting base 1101, and nylon plates 1104 are simultaneously installed on the top of the support columns 1103. The support mechanism 11 is used to provide auxiliary support for the workpiece 12, preventing the steel plate in the workpiece 12 from tipping over. Similarly, the support mechanism 11 is quickly assembled and disassembled from the fixture base 7 via the second switching magnetic base 1102, allowing for quick and flexible movement of the support mechanism 11 on the fixture base 7 to match different types of door rings.

[0100] A weld alignment method based on the above-mentioned automatic welding fixture for automotive door rings includes the following steps:

[0101] Step 1: Preparation. The robot will pre-place each steel plate in workpiece 12. In this embodiment, the robot will arrange the steel plates into a door ring structure with a placement accuracy of 2mm.

[0102] Step 2: The robotic arm drives the gripper unit to move above the workpiece 12 that has been placed in place. The gripper unit picks up the workpiece 12 that has been placed in place through the suction cup mechanism 6. Then the robotic arm moves the workpiece 12 through the gripper unit.

[0103] When each weld seam on the workpiece 12 corresponds to the light-transmitting gap 809 in each of the first alignment mechanisms 8, it indicates that the robotic arm has moved the workpiece 12 to the target working position of the fixture unit, and then the suction cup mechanism 6 releases the workpiece 12.

[0104] Step 3: The robotic arm drives the gripper unit to lift to a certain height, so that the distance between the lens of the vision camera 302 in the vision camera mechanism 3 and the upper surface of the workpiece 12 is equal to the focal length of the vision camera 302. Then, each of the pressing finger cylinders 502 in the pressing finger mechanism 5 extends at the same time, driving the corresponding universal ball screw 503 to press against the upper surface of the workpiece 12.

[0105] Step 4: The telescopic cylinders 805 in each of the first alignment mechanisms 8 extend simultaneously, driving the corresponding light source 803 to move to face the light transmission gap 809, so that the light source 803 illuminates the corresponding weld.

[0106] Step 5: Take photos of the two ends of each weld seam using the vision camera 302, and transmit the photo data to the industrial control computer. The industrial control computer calculates the gap of each weld seam based on the photo data and calculates the difference between the gaps of different weld seams.

[0107] Based on the gaps of each weld, the differences between the gaps of different welds, and the welding requirements, the industrial control computer calculates the target positions of each steel plate in workpiece 12.

[0108] Step 6: The second alignment mechanism 9 adjusts each steel plate in the workpiece 12 to the target position. Then, the vision camera 302 takes photos of the positions at both ends of each weld seam again. The industrial control computer judges whether the weld seams in the workpiece 12 are aligned based on the photo data taken by the vision camera 302 again.

[0109] When the alignment of each weld seam in workpiece 12 is completed, each pressing finger mechanism 5 releases workpiece 12, and the light source 803 in each first alignment mechanism 8 retracts to the initial position.

[0110] If the weld seams in workpiece 12 are not aligned, repeat steps five and six until the weld seams in workpiece 12 are aligned.

[0111] The following is a detailed implementation plan:

[0112] In this embodiment, as shown in Figure 15, the workpiece 12 adopts a five-slot door ring. The workpiece 12 includes steel plate A, steel plate B, steel plate C, steel plate D, and steel plate E, five steel plates, and five weld seams.

[0113] Arrange 10 visual camera mechanisms 3, 10 finger pressing mechanisms 5, no less than 15 suction cup mechanisms 6, 5 first alignment mechanisms 8, and 5 second alignment mechanisms 9; among which, the 10 visual camera mechanisms 3 correspond to the markings ①-⑩ in Figure 15;

[0114] During weld alignment, vision camera mechanisms ①-⑩ respectively photograph the four corners of the welded edges of steel plates A-E. Specifically, vision camera mechanisms ①, ②, ③, and ④ position the four corners of steel plate A; vision camera mechanisms ③, ④, ⑤, and ⑥ position the four corners of steel plate B; vision camera mechanisms ⑤, ⑥, ⑦, and ⑧ position the four corners of steel plate C; vision camera mechanisms ⑦, ⑧, ⑨, and ⑩ position the four corners of steel plate D; and vision camera mechanisms ⑨, ⑩, ①, and ② position the four corners of steel plate E.

[0115] Visual camera mechanisms ① and ② correspond to the weld between steel plate A and steel plate E; visual camera mechanisms ③ and ④ correspond to the weld between steel plate A and steel plate B; visual camera mechanisms ⑤ and ⑥ correspond to the weld between steel plate B and steel plate C; visual camera mechanisms ⑦ and ⑧ correspond to the weld between steel plate C and steel plate D; and visual camera mechanisms ⑨ and ⑩ correspond to the weld between steel plate D and steel plate E.

[0116] After steel plates A-E are placed on the fixture unit, vision camera mechanisms ①-⑩ take photos of the corresponding weld endpoints, and the industrial control computer measures the gap of each weld and the difference between the gaps of different welds, thereby simulating and calculating the target position of steel plates A-E under the condition of meeting the welding requirements.

[0117] The second alignment mechanism 9 adjusts the corresponding steel plates, and continuously feeds back the position information of steel plates A-E from the industrial control computer through vision camera mechanism ①-vision camera mechanism ⑩, thereby adjusting steel plates A-E to the target positions respectively.

[0118] Then, the vision camera mechanism ①-vision camera mechanism ⑩ confirms whether each weld meets the tolerance requirements in the welding requirements. In this embodiment, the tolerance requirement is within ±0.05mm. If the tolerance requirement is met, the weld alignment is completed; if not, the position of the corresponding steel plate is finely adjusted again by the second alignment mechanism 9. The vision camera mechanism ①-vision camera mechanism ⑩ continuously feeds back the position information of steel plate A-steel plate E from the industrial control computer until each weld meets the tolerance requirements.

[0119] This invention can be applied to the welding of single and double door rings with 3 to 10 seams, enabling flexible and automatic welding of the weld seams.

[0120] The above description is an explanation of the present invention and not a limitation thereof. The scope of the present invention is defined by the claims. Within the scope of protection of the present invention, any form of modification may be made.

Claims

1. A positioning and clamping fixture for automatic welding of automotive door rings, characterized in that: Including the gripper unit and the clamp unit, the gripper unit is connected with the working end of the mechanical arm; The gripper unit includes a gripper frame (2), the bottom of the gripper frame (2) is respectively matched with a plurality of visual camera mechanisms (3) and a plurality of suction disc mechanisms (6), the gripper unit takes a photo on the weld on the workpiece (12) through the visual camera mechanism (3), the gripper unit sucks up the workpiece (12) through the suction disc mechanism (6), thereby the workpiece (12) is carried to the target working position of the clamp unit through the mechanical arm; The clamp unit includes a clamp base (7), the top of the clamp base (7) is matched with a plurality of first alignment mechanisms (8), the first alignment mechanism (8) is used for clamping the workpiece (12), a single first alignment mechanism (8) is provided with a light source (803), the light source (803) is arranged below the workpiece (12), the light source (803) illuminates the workpiece (12) from the back of the workpiece (12), so that the visual camera mechanism (3) positions the weld on the workpiece (12).

2. The aligning and clamping tooling for automatic tailor welding of automobile door rings as claimed in claim 1, wherein: The structure of a single first alignment mechanism (8) is: including a first mounting base (801), at least one first switch magnetic base (802) is fixed on the first mounting base (801), the first alignment mechanism (8) is connected with the clamp base (7) through the first switch magnetic base (802), the top of the first mounting base (801) is fixed with a connecting seat (804), the connecting seat (804) is fixed with a telescopic cylinder (805), the output end of the telescopic cylinder (805) is connected with the light source (803), the top of the connecting seat (804) is fixed with a seat plate (807), a strip-shaped through hole is formed in the end face of the seat plate (807), a plurality of electromagnets (806) are installed on the top of the seat plate (807), a light transmission gap (809) is formed between adjacent two electromagnets (806), the light transmission gap (809) is arranged corresponding to the strip-shaped through hole; The telescopic cylinder (805) drives the light source (803) to move linearly, so that the light source (803) irradiates the workpiece (12) from the back of the workpiece (12) through the light transmission gap (809).

3. The aligning and clamping tooling for automatic tailor welding of automobile door rings as claimed in claim 1, wherein: The bottom of the gripper frame (2) is fixed with a fixed plate group (4), the fixed plate group (4) includes a plurality of first fixed plates and a plurality of second fixed plates, at least one suction disc mechanism (6) is matched and installed on each first fixed plate and second fixed plate; For a single first fixed plate, at least one visual camera mechanism (3) is also matched and installed, and a pressing finger mechanism (5) is arranged corresponding to the visual camera mechanism (3).

4. The aligning and clamping tooling for automatic tailor welding of automobile door rings as claimed in claim 3, wherein: The structure of the single visual camera mechanism (3) comprises a camera mounting plate (301) on which a visual camera (302) is fixed, a plurality of first quick locking devices (303) are arranged on the camera mounting plate (301) around the visual camera (302), the visual camera mechanism (3) is connected to the first fixing plate through the first quick locking device (303), and first and second fixing pin holes (305) and (306) are respectively formed in the end face of the camera mounting plate (301), and the visual camera mechanism (3) is positioned on the mounting position of the first fixing plate through the first and second fixing pin holes (305) and (306).

5. The aligning and clamping tooling for automatic tailor welding of automobile door rings as claimed in claim 3, wherein: The structure of the single pressing finger mechanism (5) comprises a pressing finger mounting seat (501) on which a plurality of second quick locking devices (505) are fixed, the pressing finger mechanism (5) is connected to the first fixing plate through the second quick locking device (505), a plurality of pressing finger air cylinders (502) are fixed to the bottom of the pressing finger mounting seat (501), and a universal ball head screw (503) is connected to the output end of the single pressing finger air cylinder (502). The pressing finger air cylinder (502) drives the corresponding universal ball head screw (503) to extend, so that the universal ball of the corresponding universal ball head screw (503) abuts against the workpiece (12).

6. The aligning and clamping tooling for automatic tailor welding of automobile door rings as claimed in claim 3, wherein: The structure of the single suction disc mechanism (6) comprises a suction disc mounting seat (601) which is installed in cooperation with the fixing plate group (4) through a rotating plunger (605), a suction disc (602) is installed on the bottom of the suction disc mounting seat (601) through a spring rod (603), a suction disc air pipe joint (604) for connecting an external air source is installed on the top of the suction disc mounting seat (601), and the external air source drives the suction disc (602) to suck up the workpiece (12) through the suction disc air pipe joint (604).

7. The aligning and clamping tooling for automatic tailor welding of automobile door rings as claimed in claim 1, wherein: The gripper unit is installed in cooperation with the working end of the mechanical arm through the gripper quick change mechanism (1), the structure of the gripper quick change mechanism (1) comprises a quick change mounting plate (101), a flat quick change mounting surface (102) is arranged on the top end face of the quick change mounting plate (101), and the gripper quick change mechanism (1) is connected to the working end of the mechanical arm through the quick change mounting surface (102). A plurality of quick change locking devices (104) and a plurality of quick change positioning pins (103) are installed on the bottom of the quick change mounting plate (101), and the gripper quick change mechanism (1) is locked and connected to the gripper frame (2) through the quick change locking device (104).

8. The aligning and clamping tooling for automatic tailor welding of automobile door rings as claimed in claim 1, wherein: The top of the clamp base (7) is fixed with a positioning tool (10) for positioning the arrangement position of the first alignment mechanism (8), the positioning tool (10) comprises a mounting bracket (1002), the top of the mounting bracket (1002) is fixed with a positioning plate (1001), a plurality of positioning corners (1003) are arranged at the edge of the positioning plate (1001), and the positioning corners (1003) correspond to the first alignment mechanism (8) one by one.

9. The aligning and clamping tool for automatic tailor welding of automobile door ring according to claim 6, characterized in that: A plurality of support mechanisms (11) for supporting the workpiece (12) are further mounted on the top of the clamp base (7), and the structure of a single support mechanism (11) is as follows: comprising a second mounting base (1101), at least one second on-off magnetic base (1102) is fixed to the bottom of the second mounting base (1101), the support mechanism (11) is connected to the clamp base (7) through the second on-off magnetic base (1102), a plurality of support columns (1103) are fixed to the top of the second mounting base (1101), and nylon plates (1104) are simultaneously mounted on the top of the support columns (1103).

10. A welding seam alignment method for an alignment clamping tool for automatic tailor welding of an automobile door ring based on the automobile door ring according to claim 1, characterized in that: Comprising the following steps: Step 1: preparation, the workpiece (12) is placed in each steel plate by a robot; Step 2: the mechanical arm drives the gripper unit to move above the workpiece (12) placed in position, the gripper unit sucks the workpiece (12) placed in position through the suction disc mechanism (6), and then the mechanical arm moves the workpiece (12) through the gripper unit; When each weld on the workpiece (12) corresponds to the light transmission gap (809) in each first alignment mechanism (8), it indicates that the mechanical arm moves the workpiece (12) to the target working position of the gripper unit, and then the suction disc mechanism (6) releases the workpiece (12); Step 3: the mechanical arm drives the gripper unit to lift a certain height, so that the distance between the lens of the vision camera (302) in the vision camera mechanism (3) and the upper surface of the workpiece (12) is equal to the focal length of the vision camera (302), and then each pressing finger cylinder (502) in the pressing finger mechanism (5) is extended at the same time, driving the corresponding universal ball head screw (503) to abut against the upper surface of the workpiece (12); Step 4: the extension cylinders (805) in each first alignment mechanism (8) are extended at the same time, driving the corresponding light source (803) to move to directly opposite the light transmission gap (809), so that the light source (803) irradiates the corresponding weld; Step 5: the vision camera (302) takes photos of the positions at both ends of each weld, and transmits the photo data to the industrial computer, and the industrial computer calculates the gap of each weld according to the photo data, and calculates the difference between different weld gaps; According to the gap of each weld, the difference between different weld gaps, and the welding requirements, the industrial computer calculates the target position of each steel plate in the workpiece (12). Sixth step: adjust each steel plate in the workpiece (12) to the target position through the second alignment mechanism (9), and then take a photo of the position at both ends of each weld seam through the vision camera (302) again. The industrial computer determines whether the alignment of each weld seam in the workpiece (12) is completed according to the photo data taken by the vision camera (302) again. When the alignment of each weld seam in the workpiece (12) is completed, each pressing finger mechanism (5) releases the workpiece (12), and the light source (803) in each first alignment mechanism (8) is retracted to the initial position. When the alignment of each weld seam in the workpiece (12) is not completed, repeat the fifth step and the sixth step until the alignment of each weld seam in the workpiece (12) is completed.

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