Flexible self-positioning device for automated resistance spot welding and its application method

Abstract

This invention provides a flexible self-positioning device and its method of use for automated resistance spot welding. The positioning device includes a control cabinet, a positioning fixture, a spot welding machine, and a robot. The positioning fixture is used to install and place the part to achieve relative fixation between the part and the welding machine. The spot welding machine is electrically connected to the control cabinet. The robot includes a multi-degree-of-freedom robotic arm, a clamping part, and a positioning part. The clamping part is connected to the end of the robotic arm, and the positioning part is connected to the clamping part. The robotic arm and the clamping part are electrically connected to the control cabinet. The control cabinet can control the movement of the robotic arm to make the positioning part engage with the locking part, and the control cabinet can control the clamping part to clamp or release the part. This invention has low system modification costs and can realize automated clamping and spot welding of parts, which reduces human labor intensity and improves efficiency.

Description

Technical Field

[0001] This invention relates to the field of automated manufacturing technology, and more specifically, to a flexible self-positioning device and method for automated resistance spot welding. Background Technology

[0002] With the rapid development of computer technology, welding robots and mechanized and automated welding production lines are widely used in resistance welding production. The automotive industry is one of the industries that uses spot welding robots extensively. The application method is mostly that the robot loads the welding gun and performs spot welding according to the program. In order to ensure welding quality, spot welding robots must not only have sufficient load capacity, but also have fast point-to-point movement speed, smooth movements, and accurate positioning, thereby shortening the movement time and improving work efficiency.

[0003] For small-scale resistance spot welding enterprises, the resistance spot welding of small parts is generally carried out by workers manually handling the parts. If continuous spot welding is required, the labor intensity of workers will increase significantly, resulting in extremely low efficiency. To achieve automated spot welding, improve efficiency, and save costs without abandoning existing fixed spot welding machines, the automated method of automatically grasping and moving workpieces as described in this invention can be adopted.

[0004] In automated spot welding processes, to ensure positioning accuracy, the parts need a high positioning reference as the basis for the robot's movement. Furthermore, the spot welding process requires the parts to be in a fully relaxed state to ensure sufficient welding pressure; otherwise, the welding quality will be affected.

[0005] There are usually two ways to resolve this contradiction. One is to use a robot with adaptive functions, which will inevitably increase costs. The other is to set up elastic mechanisms such as springs in the spot welding direction of the part tooling, so that the compression or extension of the springs can adapt to the pressure of the spot welding electrode during spot welding. However, this method will sacrifice the accuracy of the weld point position, especially for complex structures, narrow-distance weld points, and continuous spot welding, which will bring more problems. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] The technical problem to be solved by this invention is how to achieve high-precision positioning of parts and high welding quality at a lower cost during automated spot welding processes.

[0008] (II) Technical Solution

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] In a first aspect, the present invention provides a flexible self-positioning device for automated resistance spot welding, used for welding parts with snap-fit ​​parts, including a control cabinet, a positioning fixture, a spot welding machine, and a robot; the positioning fixture is used to install and place the part to achieve relative fixation between the part and the spot welding machine; the spot welding machine is electrically connected to the control cabinet; the robot includes a multi-degree-of-freedom robotic arm, a clamping part, and a positioning part, the end of the robotic arm is connected to the clamping part, the clamping part is connected to the positioning part, and the robotic arm and the clamping part are electrically connected to the control cabinet; wherein, the control cabinet can control the movement of the robotic arm to make the positioning part engage with the snap-fit ​​part, and the control cabinet can control the clamping part to clamp or release the part.

[0011] In one embodiment, the part is a hollow cylindrical structure, and the inner wall of the cylindrical structure is provided with a plurality of the snap-fit ​​parts, and the positioning part can cooperate with the snap-fit ​​parts for connection.

[0012] In one embodiment, the snap-fit ​​portion is a protruding structure, the positioning portion is a guide post, and the guide post is provided with a slot that matches the shape of the protruding structure.

[0013] In one embodiment, the opening of the slot is trumpet-shaped.

[0014] In one embodiment, the clamping part is a pneumatic finger, and the positioning part is provided on the pneumatic finger; or, the clamping part is a chuck with multiple jaws, and the positioning part is provided on the jaws.

[0015] In one embodiment, the flexible self-positioning device for automated resistance spot welding further includes an electromagnetic switching valve electrically connected to the clamping part and the control cabinet.

[0016] In one embodiment, the flexible self-positioning device for automated resistance spot welding further includes multiple control cables. The control cabinet is provided with multiple output terminals for issuing control signals and multiple input terminals for receiving feedback signals. The multiple control cables are electrically connected to the corresponding output terminals or the corresponding input terminals, respectively.

[0017] Secondly, the present invention also provides a method of using a flexible self-positioning device for automated resistance spot welding, the method comprising the following steps:

[0018] Step 1: Install the part onto the positioning fixture;

[0019] Step 2: The control cabinet controls the movement of the robotic arm so that the positioning part and the locking part can be connected and the clamping part can be controlled to clamp the part, thereby realizing the positioning and gripping of the part;

[0020] Step 3: The robotic arm moves the part between the upper and lower electrodes of the spot welding machine so that the weld point of the part is aligned with the upper electrode of the spot welding machine.

[0021] Step 4: The control cabinet controls the upper electrode to descend, and the upper electrode is pressed down to the position of the solder joint;

[0022] Step 5: The control cabinet controls the movement of the robotic arm to disengage the positioning part from the locking part.

[0023] To release the parts;

[0024] Step 6: Apply power to the upper electrode and weld the upper electrode to the specified weld point location;

[0025] Step 7: After the welding at the specified weld point is completed, repeat step 2, and then lift the upper electrode;

[0026] Step 8: The robotic arm moves the part so that another weld point of the part is aligned with the upper electrode of the spot welding machine, and steps 4 to 7 are repeated until all weld points are welded.

[0027] In one embodiment, the method of use further includes:

[0028] Step 9: The robotic arm moves the welded part to the commanded position.

[0029] (III) Beneficial Effects

[0030] The above-described technical solution of the present invention has at least the following advantages:

[0031] 1. This invention only requires adding a regular robot to an existing spot welding machine in terms of main hardware. The robot does not need to be equipped with advanced functions, resulting in low system modification costs. During the entire spot welding process, workers only need to place the parts on the positioning fixture or remove the spot-welded parts. The clamping and spot welding process of the entire parts requires no manual intervention, which reduces labor intensity and improves efficiency.

[0032] 2. The locking part and the positioning part of the present invention cooperate to continuously clamp or release the parts during the spot welding process, and also maintain the relative position stability between the parts and the robotic arm. This ensures both the positional accuracy of the spot welding point and the welding quality, and is suitable for automated spot welding of complex parts.

[0033] 3. The positioning part of this invention connects with the snap-fit ​​part on the part, enabling precise clamping of the part and ensuring positioning accuracy. Furthermore, this clamping position can serve as a reference for the initial position of the robot's movement. During spot welding, the positioning part disengages from the snap-fit ​​part on the part, allowing the part to relax and ensuring that the upper electrode of the spot welding machine can press down sufficiently to achieve a stable connection at the spot welding position and improve welding quality. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of the structure of a flexible self-positioning device for automated resistance spot welding provided in an embodiment of the present invention.

[0036] Figure 2 This is a structural schematic diagram of the part provided in an embodiment of the present invention.

[0037] Figure 3 This is a schematic diagram of the cooperation state between the positioning part and the snap-fit ​​part provided in an embodiment of the present invention.

[0038] Figure 4 This is a flowchart illustrating the usage method of the flexible self-positioning device for automated resistance spot welding provided in an embodiment of the present invention.

[0039] The labels for the attached figures are as follows:

[0040] 1. Part; 2. Positioning fixture; 3. Robotic arm; 4. Clamping part; 5. Positioning part; 6. Electromagnetic switch valve; 7. Control cabinet; 8. Spot welding machine; 9. Control cable; 11. Connecting part; 12. First window; 13. Second window; 14. Continuous welding point; 51. Slot. Detailed Implementation

[0041] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0042] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be located directly on or indirectly on the other component. When a component is referred to as "connected to" another component, it can be directly or indirectly connected to the other component.

[0043] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate that the device or element must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0044] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating relative importance or the number of technical features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. The specific implementation of this invention will be described in more detail below with reference to specific embodiments:

[0045] like Figure 1 , Figure 2 and Figure 3 As shown, this embodiment of the invention provides a flexible self-positioning device for automated resistance spot welding, used for welding a part 1 with a locking part 11. The device includes a control cabinet 7, a positioning fixture 2, a spot welding machine 8, and a robot. The positioning fixture 2 is used to install and place the part 1 to achieve relative fixation between the part 1 and the spot welding machine 8. The spot welding machine 8 is electrically connected to the control cabinet 7. The robot includes a multi-degree-of-freedom robotic arm 3, a clamping part 4, and a positioning part 5. The end of the robotic arm 3 is connected to the clamping part 4, and the clamping part 4 is connected to the positioning part 5. The robotic arm 3 and the clamping part 4 are electrically connected to the control cabinet 7. The control cabinet 7 can control the movement of the robotic arm 3 to allow the positioning part 5 to engage with the locking part 11, and the control cabinet 7 can control the clamping part 4 to clamp or release the part 1.

[0046] In one embodiment, part 1 is a hollow cylindrical structure, and a plurality of snap-fit ​​parts 11 are provided on the inner wall surface of the cylindrical structure, and the positioning part 5 can be connected with the snap-fit ​​parts 11.

[0047] In one embodiment, the snap-fit ​​part 11 is a protruding structure, the positioning part 5 is a guide post, and the guide post is provided with a slot 51 that matches the shape of the protruding structure.

[0048] In one embodiment, the opening of the slot 51 is trumpet-shaped.

[0049] In one embodiment, the clamping part 4 is a pneumatic finger with a positioning part 5, or the clamping part 4 is a chuck with multiple jaws with a positioning part 5.

[0050] In one embodiment, the flexible self-positioning device for automated resistance spot welding also includes an electromagnetic switch valve 6, which is electrically connected to the clamping part 4 and the control cabinet 7.

[0051] In one embodiment, the flexible self-positioning device for automated resistance spot welding also includes multiple control cables 9. The control cabinet 7 is provided with multiple output terminals for issuing control signals and multiple input terminals for receiving feedback signals. The multiple control cables 9 are electrically connected to the corresponding output terminals or the corresponding input terminals respectively.

[0052] Figure 2 and Figure 3 A specific embodiment of the present invention is provided as follows:

[0053] Part 1 Figure 2 As shown, the exterior of part 1 is smooth, making it difficult to stably clamp using ordinary fixtures. However, part 1 has multiple protruding structures inside, and the dimensional accuracy of these protrusions is high. The welding locations are two square windows (the first window 12 and the second window 13, respectively). Welding requires continuous spot welding around the windows to form continuous weld points 14. Since continuous spot welding requires a certain amount of overlap to ensure a seal, the position of the weld points is critical. Simultaneously, the welding quality required for this part is high, and spot welding spatter is not permitted. The flexible self-positioning device for automated resistance spot welding provided by this invention is used for spot welding. The positioning fixture 2 can be designed as a platform with a V-groove. The V-groove is used to accommodate the cylindrical part 1. Two protrusions can also be provided within the V-groove, with shapes corresponding to the shapes of the first window 12 and the second window 13, respectively, to secure the protrusions within the first window 12 or the second window 13, thereby achieving the positioning of part 1. This facilitates the subsequent clamping of part 1 by the robotic arm 3 using this positioning reference.

[0054] like Figure 4 As shown, the control cabinet 7 is equipped with a first output terminal A, a second output terminal B, a third output terminal C, and a fourth output terminal D. These output terminals can send control signals to their corresponding connected structures. Specifically, the first output terminal A is electrically connected to the robotic arm 3 and the clamping part 4, and is used to output signals controlling the movement of the robotic arm 3 and controlling the clamping part 4 to grasp or release parts. The second output terminal B is connected to a drive device that controls the movement of the upper electrode, and is used to control the upper electrode to lift or lower. The third output terminal C is connected to a pressing device that controls the pressure applied to the upper electrode, and is used to control the upper electrode to pre-press the part 1. The fourth output terminal D is connected to the upper electrode and is used to control the on / off state of the upper electrode current. In a second aspect, the present invention also provides a method of using a flexible self-positioning device for automated resistance spot welding, the method comprising the following steps:

[0055] Step 1: Install part 1 onto positioning fixture 2;

[0056] Step 2: Control cabinet 7 controls the movement of robotic arm 3 so that positioning part 5 and locking part 11 can be connected and clamping part 4 can be controlled to clamp part 1, thereby achieving positioning and gripping of part 1.

[0057] Step 3: The robotic arm 3 moves part 1 between the upper and lower electrodes of the spot welding machine 8 so that the welding point of part 1 is aligned with the upper electrode of the spot welding machine 8. Before this, a structure for detecting whether the upper electrode has descended can be set on the spot welding machine. Step 3 is executed only when the descent of the upper electrode is detected. When the descent of the upper electrode is detected, a signal is fed back to the control cabinet 7 so that the control cabinet 7 continues to send a signal to control the descent of the upper electrode through the second output terminal B.

[0058] Step 4: Control cabinet 7 controls the upper electrode to descend, pressing it down to the welding point position. Similarly, before this, a structure can be set on the spot welding machine to detect whether the upper electrode has moved. Step 4 is executed only when the descent of the upper electrode is detected to be complete; if the upper electrode has not descended, a signal is fed back to control cabinet 7 so that control cabinet 7 can continue to send a signal to control the descent of the upper electrode through the second output terminal B.

[0059] Step 5: Control cabinet 7 controls the movement of robotic arm 3 to disengage positioning part 5 from locking part 11.

[0060] Release part 1;

[0061] Step Six: Power on the upper electrode and weld the weld point on the upper electrode. Before this, a structure can be set on the spot welding machine to detect whether the power supply to the upper electrode has ended. Step Seven is executed only when no current is detected on the upper electrode. When current is detected on the upper electrode, the signal is fed back to the control cabinet 7 so that the control cabinet 7 controls the upper electrode to continue spot welding through the fourth output terminal D.

[0062] Step 7: After welding at the solder joint, repeat step 2, and then lift the upper electrode;

[0063] Step 8: The robotic arm 3 moves the part so that another welding point of part 1 is aligned with the upper electrode of the spot welding machine 8, and repeats steps 4 to 7 until all welding points are completed.

[0064] Step 9: Move the robotic arm 3 to the commanded position after welding part 1.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of using a flexible self-positioning device for automated resistance spot welding, for welding a part having a clasp, characterized in that, Flexible self-positioning devices for automated resistance spot welding include: Control cabinet; The spot welding machine is electrically connected to the control cabinet; Positioning fixtures are used to install and place the parts so as to fix the relative position of the parts and the spot welding machine; The robot includes a multi-degree-of-freedom robotic arm, a gripping part, and a positioning part. The end of the robotic arm is connected to the gripping part, and the gripping part is connected to the positioning part. The robotic arm and the gripping part are electrically connected to the control cabinet. The control cabinet can control the movement of the robotic arm so that the positioning part and the snap-fit ​​part can be connected. The control cabinet can also control the clamping part to clamp or release the part. The method of use includes the following steps: Step 1: Install the part onto the positioning fixture; Step 2: The control cabinet controls the movement of the robotic arm so that the positioning part and the locking part can be connected and the clamping part can be controlled to clamp the part, thereby realizing the positioning and gripping of the part; Step 3: The robotic arm moves the part between the upper and lower electrodes of the spot welding machine so that the weld point of the part is aligned with the upper electrode of the spot welding machine. Step 4: The control cabinet controls the upper electrode to descend, and the upper electrode is pressed down to the position of the solder joint; Step 5: The control cabinet controls the movement of the robotic arm to disengage the positioning part from the locking part. To release the parts; Step 6: Apply power to the upper electrode and weld the upper electrode to the specified weld point location; Step 7: After the welding at the specified weld point is completed, repeat step 2, and then lift the upper electrode; Step 8: The robotic arm moves the part so that another weld point of the part is aligned with the upper electrode of the spot welding machine, and steps 4 to 7 are repeated until all weld points are welded.

2. The method of using a flexible self-positioning device for automated resistance spot welding of claim 1, wherein, The part is a hollow cylindrical structure, and the inner wall of the cylindrical structure is provided with a plurality of snap-fit ​​parts, and the positioning part can be connected with the snap-fit ​​parts.

3. The method of using a flexible self-positioning device for automated resistance spot welding of claim 2, wherein, The snap-fit ​​part is a protruding structure, and the positioning part is a guide post. The guide post is provided with a slot that matches the shape of the protruding structure.

4. The method of using a flexible self-positioning device for automated resistance spot welding of claim 3, wherein, The opening of the card slot is trumpet-shaped.

5. The method of using a flexible self-positioning device for automated resistance spot welding of claim 1, wherein, The clamping part is a pneumatic finger, and the positioning part is provided on the pneumatic finger. Alternatively, the clamping part is a chuck with multiple jaws, and the positioning part is provided on the jaws.

6. The method of using the flexible self-positioning device for automated resistance spot welding as described in claim 1, characterized in that, The flexible self-positioning device for automated resistance spot welding also includes an electromagnetic switch valve, which is electrically connected to the clamping part and the control cabinet.

7. The method of using the flexible self-positioning device for automated resistance spot welding as described in claim 1, characterized in that, The flexible self-positioning device for automated resistance spot welding also includes multiple control cables. The control cabinet is equipped with multiple output terminals for sending control signals and multiple input terminals for receiving feedback signals. The multiple control cables are electrically connected to the corresponding output terminals or corresponding input terminals respectively.

8. The method of using the flexible self-positioning device for automated resistance spot welding as described in claim 1, characterized in that, The method of use also includes: Step 9: The robotic arm moves the welded part to the commanded position.

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