Automatic screw tightening robot for automobile assembly production line

Abstract

The invention relates to the field of automobile production, in particular to an automatic screw tightening robot for an automobile assembly production line, which comprises an industrial machine rack, the industrial machine rack comprises a plurality of racks for electric wrenches to move up and down, and the output end of each electric wrench is connected with a sleeve for screwing a screw; supporting plates are symmetrically arranged on the two sides of the bottom of the industrial machine frame, a bearing plate is slidably connected to the supporting plates, each station comprises two sliding grooves symmetrically penetrating through the bearing plate, a kidney-shaped hole is formed between every two adjacent sliding grooves, a sliding plate is arranged at the position, opposite to the kidney-shaped holes, below the bearing plate, and the sliding plates are slidably connected with the sliding grooves. A placement hole and a receding hole are formed in the sliding plate; the production efficiency and the production takt are greatly improved, a plurality of screws work in parallel and are continuously tightened at a high speed, a plurality of electric wrenches and tightening sleeves can be integrated, simultaneous or rapid sequential tightening of the plurality of screws is achieved, and traditional manual serial circulation of'picking-positioning-screwing-tightening 'is converted into highly parallel automatic work.

Description

Technical Field

[0001] This invention relates to the field of automobile manufacturing, specifically to an automatic screw tightening robot for automobile assembly lines. Background Technology

[0002] In automotive assembly lines, screw tightening is a critical process involving multiple stages, including body structure components, interior parts, chassis components, and powertrain assembly. Its quality and efficiency directly impact the overall vehicle assembly quality, production cycle time, and manufacturing costs. Traditional screw tightening operations primarily rely on manual labor: operators use an electric or pneumatic tightening tool to pick up screws one by one from the material box, locate and position them in the corresponding threaded holes on the parts, and then activate the tool to screw them in and tighten. While this method is simple and flexible, it increasingly fails to meet the demands of modern automotive manufacturing for high efficiency, high precision, and high consistency, exhibiting the following significant technical shortcomings: First, the low efficiency of the operation severely restricts the production cycle. Since each screw requires a complete manual cycle of "pick-up-position-screw-tighten," the entire tightening process is extremely time-consuming for parts containing dozens or even hundreds of screws (such as door panels, dashboard brackets, engine mounts, etc.). In large-scale assembly line production aiming for higher production cycles, this has become a significant bottleneck. The repetitive, high-intensity labor also easily leads to worker fatigue, further reducing work speed and stability.

[0003] Secondly, the precision and consistency of manual operation are difficult to guarantee, affecting assembly quality. Key parameters such as tightening torque, angle, and final tightening depth of screws manually rely heavily on worker experience and feel, or require manual operation of tightening tools with preset torque functions. This method makes it difficult to achieve high consistency in tightening parameters for each screw, easily leading to some screws becoming loose due to insufficient torque, or stripping or even damaging the threads of parts due to excessive torque, thus affecting the reliability, safety, and NVH performance of the entire vehicle structure. Quality control mainly relies on later torque sampling inspections, making 100% real-time monitoring and data traceability impossible.

[0004] Furthermore, there is a significant risk of "screw mismatch." Modern automotive parts typically have densely packed screw assembly points and may use screws of various specifications (such as diameter, length, thread type, and strength grade). In fast-paced, repetitive operations, workers are highly susceptible to accidentally taking the wrong screw from the material box or screwing the correct screw into the wrong hole. This mismatch between screw and hole type can lead to anything from poor thread fit and reduced connection strength to serious damage to the threaded hole (such as stripping or cross-threading), threatening the entire component with rework or even scrap, resulting in direct material and labor losses. Although visual differentiation can be achieved by using compartmentalized material boxes, it cannot completely eliminate human error.

[0005] Therefore, an automatic screw tightening robot for automobile assembly lines is proposed to address the above problems. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0007] The technical solution adopted by the present invention to solve its technical problem is: the present invention provides an automatic screw tightening robot for an automobile assembly line, which includes an industrial machine frame, the industrial machine frame including a frame for multiple electric wrenches to move up and down, and the output end of each electric wrench is connected to a sleeve for tightening screws. The industrial machine frame has symmetrical support plates on both sides of its bottom. A bearing plate is slidably connected to the support plate. The bearing plate has multiple positions for positioning screws. Each position includes two symmetrical sliding grooves that penetrate the bearing plate. An oblong hole is opened between two adjacent sliding grooves. A sliding plate is set below the bearing plate, opposite to the oblong hole. The sliding plate is slidably connected to the sliding groove. The sliding plate has a placement hole and a clearance hole. The diameter of the placement hole is smaller than that of the clearance hole, and the placement hole is connected to the adjacent clearance hole.

[0008] Preferably, a positioning component is provided below the support plate, and the positioning component includes two setting servo motors. Each servo motor has a pressing plate fixed to its output end. The end of the pressing plate is arc-shaped. Two adjacent pressing plates deflect synchronously to press the screw into the placement hole.

[0009] Preferably, each of the placement holes has an arc-shaped extension plate at its lower edge, the extension plate being positioned away from the clearance hole, and the extension plate cooperating with two adjacent compression plates to securely wrap the screw.

[0010] Preferably, a sliding hole is provided on one side of each of the waist-shaped holes. The sliding hole communicates with the waist-shaped hole and is arranged parallel to two adjacent sliding grooves. A top plate is provided inside the sliding hole. The top plate is fixed to the sliding plate and close to the placement hole. The top plate is used to press against the side wall of the screw end.

[0011] Preferably, the lower surface of the bearing plate is provided with a vibration motor, the extrusion plate applies extrusion force to the screw, and the vibration generated by the vibration motor causes the screw to be close to the inner side wall of the extension plate, and the side wall of the screw end is attached to the end face of the top plate.

[0012] Preferably, multiple No. 1 rollers are provided on the vertical sidewalls of the pallet, and multiple No. 2 rollers are provided on the top lower surface of the pallet. The No. 1 rollers press against the two side walls of the support plate, and the No. 2 rollers press against the upper surface of the support plate.

[0013] Preferably, the electric wrench has a support plate on its outer casing, and a positioning rod is slidably connected to the support plate. The upper end of the positioning rod is connected to the support plate by a spring.

[0014] Preferably, each of the sleeves is connected to a negative pressure pipe, which extends upward through the support plate, and the end of the negative pressure pipe is fitted with a sleeve, with an air outlet on the outer wall of the sleeve.

[0015] Preferably, a receiver is provided on the outer wall of each sleeve; an infrared transmitter is provided on the industrial machine frame at a position opposite to the receiver.

[0016] Preferably, guide grooves are symmetrically formed on both sides of the lower surface of the support plate; guide wheels are provided on the bottom upper surface of the tray.

[0017] The advantages of this invention are: 1. The screw-tightening robot designed in this invention greatly improves production efficiency and production cycle. It can tighten multiple screws in parallel and at high speed. It can integrate multiple electric wrenches and tightening sockets to achieve simultaneous or rapid sequential tightening of multiple screws, transforming the traditional manual serial cycle of "pick-position-screw-tighten" into a highly parallel automated operation.

[0018] 2. In this invention, the cycle time is greatly shortened. Compared with manual operation, the robot system can complete the tightening of all target screws on a part in a few seconds, which completely breaks the efficiency bottleneck of the process and significantly improves the overall cycle time of the production line, meeting the needs of large-scale, high-paced modern production.

[0019] 3. Achieving high consistency and traceability in assembly quality, this electric wrench can be equipped with an integrated intelligent tightening torque wrench, which can perform high-precision, programmed control on key parameters such as torque, angle, and speed of each screw, ensuring that each tightening point meets completely consistent process standards, greatly improving connection reliability and overall vehicle quality. Attached Figure Description

[0020] Figure 1 This is a perspective view of the working state of the automatic screw tightening robot in this invention; Figure 2This is a side view of the working state of the automatic screw tightening robot in this invention; Figure 3 This is a front view of the automatic screw tightening robot of the present invention; Figure 4 This is a perspective view of the automatic screw tightening robot of the present invention; Figure 5 This is a perspective view of the assembly of the industrial machine frame and the support plate in this invention; Figure 6 This is a perspective view of the industrial machine frame in this invention; Figure 7 This is a perspective view of the electric wrench in this invention; Figure 8 This is a cross-sectional view of the sleeve in this invention; Figure 9 This is a first-view perspective view of the support plate in this invention; Figure 10 This is a second-view perspective perspective view of the support plate in this invention; Figure 11 This is a top view of the support plate in this invention; Figure 12 This is a bottom view of the support plate in this invention; Figure 13 This is a schematic diagram illustrating the fit between the sliding hole and the oblong hole in this invention; Figure 14 This is a first-view perspective perspective view of the skateboard in this invention; Figure 15 This is a second-view perspective perspective view of the skateboard in this invention; In the diagram: 1. Industrial machine frame; 2. Gear motor; 3. Screw; 4. Machine frame; 5. Electric wrench; 6. Socket; 7. Support plate; 8. Bearing plate; 9. Slide groove; 10. Waist-shaped hole; 11. Slide plate; 12. Screw; 13. Placement hole; 14. Clearance hole; 15. Guide rail; 16. Servo motor; 17. Extrusion plate; 18. Extension plate; 19. Slide hole; 20. Top plate; 21. Vibration motor; 22. Roller No. 1; 23. Roller No. 2; 24. Support plate; 25. Positioning rod; 26. Negative pressure pipe; 27. Sleeve; 28. Air outlet; 29. ​​Receiver; 30. Infrared transmitter; 31. Guide groove; 32. Guide wheel; 33. Recess; 34. Ring body; 35. Positioning hole. Detailed Implementation

[0021] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0022] This invention aims to address the shortcomings of existing screw tightening methods in automotive assembly lines, which fail to meet the demands of modern automotive manufacturing for high efficiency, high precision, and high consistency. It provides an industrial robot capable of automatically tightening automotive assembly screws, as detailed below: Reference Figure 1 - Figure 15 The system includes an industrial machine frame 1 and a control system. The industrial machine frame 1 is equipped with a geared motor 2. The output end of the geared motor 2 is fixedly connected to a lead screw, which extends into the frame 4. The outer shell of the electric wrench 5 is threadedly connected to the lead screw and slidably connected within the frame 4. The electric wrench 5 can be driven to move up and down by the geared motor 2. The output end of each electric wrench 5 is connected to a sleeve 6 for tightening screws 3. The sleeve 6 is a magnetic sleeve 6 that can attract the end of the screw 3. The industrial machine frame 1 has symmetrical support plates 7 on both sides of its bottom. A bearing plate 8 is slidably connected to the support plate 7. The bearing plate 8 has multiple positions for positioning screws 3. Each position includes two symmetrical sliding grooves 9 that penetrate the bearing plate 8. An oblong hole 10 is opened between two adjacent sliding grooves 9. A sliding plate 11 is set below the bearing plate 8 at a position opposite to the oblong hole 10. The sliding plate 11 is slidably connected to the sliding groove 9. A screw 12 is set on one side of the sliding groove 9 to drive the sliding plate 11 to move. The screw 12 is threaded to the sliding plate 11. The screw 12 can be driven to rotate by a motor to realize the movement of the sliding plate 11. The sliding plate 11 has a placement hole 13 and a clearance hole 14. The diameter of the placement hole 13 is smaller than the diameter of the clearance hole 14, and the placement hole 13 is connected to the adjacent clearance hole 14. In this embodiment of the invention, the bottom of the industrial machine frame 1 is also provided with a guide rail 15, which allows the support plate 8 to enter and slide out. The support plate 8 has pre-placed screws 3 ready for assembly. The screws 3 are inserted into the placement holes 13, and then the support plate 8 slides under the industrial machine frame 1. Pre-placing the screws 3 allows for prior identification of the screw types, enabling dedicated placement based on workstation location. That is, only one type of screw 3 is placed on one side of each workstation, effectively reducing the risk of mismatched screws 3. Furthermore, pre-placing the screws 3 reduces the need for subsequent screw preparation steps, improving production efficiency. Figure 1 and Figure 2As shown, automotive parts requiring screws 3 are conveyed below the industrial machine frame 1. Specifically, a conveyor belt can be used to transport the automotive parts. A limit switch is installed on one side of the conveyor belt, linked to the conveyor belt and connected to the control system. When the automotive part is conveyed to the area below the industrial machine frame 1 and touches the limit switch, the control system stops the conveyor belt from transporting the part. At this point, the part is transported to a designated position. Then, the control system drives the electric wrench 5 to move downwards. The electric wrench 5 places the socket 6 onto the screw 3 at the placement hole 13. The socket 6 holds the screw 3. A distance sensor is installed at the top of the socket 6 to detect whether the end of the screw 3 is assembled into the socket 6. When the distance sensor detects a preset distance between the upper surface of the screw 3 end and the sensor, the distance sensor is connected to the control system. The control system operates the motor to drive the slide plate 11 to move. The slide plate 11 moves relative to the screw 3, and the screw 3 gradually moves from the placement hole 13 to the clearance hole 14. When the screw 3 moves to the clearance hole 14, both the socket 6 and the screw 3 can pass through the clearance hole. Hole 14, and the travel distance of the slide plate 11 is also controlled by the control system. When the slide plate 11 completes its travel distance, the control system outputs a command to drive the electric wrench 5 to move down again. The electric wrench 5 drives the screw 3 to move down, and at the same time outputs a command to rotate the electric wrench 5 to tighten the screw 3 onto the automotive parts. As for the tightening force, it can be fed back to the control system through the torque output of the electric wrench 5. When the torque feedback value output by the electric wrench 5 is equal to the preset torque, the control system outputs a command to stop the electric wrench 5. Subsequently, the control system outputs a command to move the electric wrench 5 up to reset, and the next support plate 8 is pushed in and the previous support plate 8 is pushed out. As for the push-in stroke of the support plate 8, it can be controlled by the push-in of the external electric push rod. The control system precisely controls the stroke of the output end of the electric push rod, thereby controlling the precise feeding stroke of the support plate 8 to ensure that the position of the screw 3 on the support plate is close to the threaded hole position on the automotive parts. When the control system outputs the command to move the electric wrench 5 up to reset, the control system can output a command to control the electric push rod to push in the next support plate 8 for feeding, and so on, repeating the above commands and actions. In this embodiment, a screw recognition system adapted to the automatic screw tightening robot is also included to determine the status of screws 3 at each workstation. Specifically, an industrial camera is set on the industrial machine frame 1. When the support plate 8 slides into the tray 7, each industrial camera takes a picture of the workstation below it and obtains an image of the workstation. The image is then uploaded to the screw recognition system and compared with a standard image to determine whether there are screws 3 or extra screws 3 at each workstation. If there are no screws 3 or extra screws 3 at one of the workstations, the automatic screw tightening robot will not perform the tightening operation, but will issue an audible and visual alarm to remind that the number of screws 3 on the support plate 8 is incorrect, so as to avoid the absence of automotive parts screws 3 and the resulting safety hazards. This automatic screw tightening robot significantly improves production efficiency and cycle time. It allows for the parallel and high-speed continuous tightening of multiple screws 3, integrating multiple electric wrenches 5 and tightening sockets 6. This enables simultaneous or rapid sequential tightening of multiple screws 3, transforming the traditional manual serial cycle of "pick-position-screw-tighten" into a highly parallel automated operation. Cycle time is drastically reduced; compared to manual operation, the robot system can complete the tightening of all target screws 3 on a component within seconds, completely breaking through the efficiency bottleneck of this process and significantly improving the overall cycle time of the production line, meeting the needs of large-scale, high-paced modern production. It also achieves high consistency and traceability of assembly quality. The electric wrench 5 can be an integrated intelligent tightening torque wrench, capable of high-precision, programmed control of key parameters such as torque, angle, and speed for each screw 3, ensuring that every tightening point meets completely consistent process standards, greatly improving connection reliability and overall vehicle quality. Meanwhile, the industrial robot also meets the requirements of industrial production. The industrial robot itself has a simple structure and operating logic, and is given program control, which has a certain degree of automation. Whether in terms of efficiency or production quality, it meets industrial indicators. In addition, the industrial robot can be designed according to actual production requirements, and different workstations can be flexibly designed to meet various working conditions for screw turning.

[0023] Reference Figure 9 - Figure 13 The support plate 8 is provided with a positioning component below it, and the positioning component includes two setting servo motors 16. Each servo motor 16 has a pressing plate 17 fixed to its output end. The end of the pressing plate 17 is arc-shaped. The two adjacent pressing plates 17 deflect synchronously to press the screw 3 into the placement hole 13. In this embodiment, the positioning component is used for positioning the screw 3 after it is placed. Considering the possibility that there may be a gap between the screw 3 and the inner wall of the placement hole 13 after the screw 3 is placed in the placement hole 13, that is, the axis of the screw 3 is not yet aligned with the axis of the sleeve 6, which will affect the subsequent cooperation between the sleeve 6 and the screw 3, the positioning component is set up for this purpose. Specifically, before the screw 3 is placed, the servo motor 16 drives the pressing plate 17 to open, the placement hole 13 is opened, and space is made for the screw 3 to be placed. After the screw 3 is placed, the servo motor 16 is driven, and the servo motor 16 drives the pressing plate 17 to deflect. The two adjacent pressing plates 17 press the screw 3 into the placement hole 13, so that the surface of the screw 3 is attached to the inner wall of the placement hole 13. At this time, the axis of the screw 3 and the axis of the sleeve 6 tend to be aligned, which helps the sleeve 6 and the screw 3 to cooperate smoothly. When the sleeve 6 moves down into place and is fitted onto the end of the screw 3, the servo motor 16 drives the pressing plate 17 to open, freeing up space for the screw 3 to move from the placement hole 13 to the clearance hole 14.

[0024] Reference Figure 14and Figure 15 Each of the placement holes 13 has an arc-shaped extension plate 18 at its lower edge. The extension plate 18 is positioned away from the clearance hole 14. The extension plate 18 cooperates with two adjacent pressing plates 17 to wrap and stabilize the screw 3. The extrusion plate 17 and the inner wall of the placement hole 13 are misaligned vertically. If the extrusion pressure of the extrusion plate 17 is too large and applied to the screw 3, the screw 3 may tilt. Therefore, an extension plate 18 is provided to increase the effective contact area between the screw 3 and the inner wall of the placement hole 13, thereby improving the stability of the screw 3 in the placement hole 13. At the same time, the extrusion pressure of the extrusion plate 17 on the screw 3 is increased, which can further improve the stability of the screw 3. Even if the bearing plate 8 vibrates during movement, the screw 3 can still maintain the expected position.

[0025] Reference Figure 9 - Figure 13 Each of the waist-shaped holes 10 has a sliding hole 19 on one side, the sliding hole 19 communicates with the waist-shaped hole 10, the sliding hole 19 is arranged parallel to the two adjacent sliding grooves 9, and a top plate 20 is provided in the sliding hole 19. The top plate 20 is fixed to the sliding plate 11 and close to the placement hole 13. The top plate 20 is used to press against the side wall of the end of the screw 3. Considering that the end of screw 3 is hexagonal prism-shaped, it can be angularly positioned so that sleeve 6 can be accurately and smoothly fitted onto the end of screw 3. Specifically, screw 3 is placed in placement hole 13, with one side wall of the end of screw 3 facing the end face of top plate 20. Under the subsequent pressing of pressing plate 17, the threaded part of screw 3 is attached to the inner side wall of placement hole 13, while one side wall of the end of screw 3 is pressed against the end face of top plate 20. The upper surface of top plate 20 is lower than the upper surface of the end of screw 3. Sleeve 6 is fitted onto screw 3, and top plate 20 moves with slide plate 11. Screw 3 moves relative to the position of clearance hole 14. Top plate 20 moves away from screw 3, and screw 3 moves upward in sleeve 6 due to magnetic attraction. Sleeve 6 completely fits and attracts the end of screw 3.

[0026] Reference Figure 10 and Figure 12 The lower surface of the bearing plate 8 is provided with a vibration motor 21. The pressing plate 17 applies a pressing force to the screw 3. The vibration generated by the vibration motor 21 causes the screw 3 to be close to the inner side wall of the extension plate 18, and the side wall of the end of the screw 3 is attached to the end face of the top plate 20. The vibration motor 21 is used to vibrate the screws 3. Specifically, before the support plate 8 is placed on the industrial machine frame 1, different screws 3 are placed in the corresponding workstations. At this time, the servo motor 16 and the vibration motor 21 are directly driven. The vibration motor 21 drives the support plate 8 to vibrate, and the support plate 8 drives the screws 3 to vibrate in the placement hole 13. At the same time, the pressing plate 17 presses the screws 3, and the screws 3 adapt to the vibration deflection of the top plate 20. Finally, one end of the screw 3 is pressed against the end face of the top plate 20. This design does not require manual placement of the screws 3, reduces the manual placement angle adjustment process, and improves the efficiency of screw placement and preparation.

[0027] Reference Figure 3 and Figure 6 Multiple first rollers 22 are provided on the vertical side wall of the pallet 7, and multiple second rollers 23 are provided on the top lower surface of the pallet 7. The first rollers 22 press against the two side walls of the bearing plate 8, and the second rollers 23 press against the upper surface of the bearing plate 8. During the process of sliding the support plate 8 onto the support plate 7, the first roller 22 presses against the two side walls of the support plate 8, so that the support plate 8 is centered between the two support plates 7, and positions it horizontally. At the same time, the second roller 23 presses against the upper surface of the support plate 8, and positions it vertically, keeping the support plate 8 pushed onto the support plate 7 in a stable state, while improving the alignment of the sleeve 6 and the screw 3.

[0028] Reference Figure 3 - Figure 6 The electric wrench 5 has a support plate 24 on its outer shell, and a positioning rod 25 is slidably connected to the support plate 24. The upper end of the positioning rod 25 is connected to the support plate 24 by a spring. The positioning rod 25 is connected to the electric wrench 5 and can move together with the electric wrench 5. When the electric wrench 5 moves down, the lower end of the positioning rod 25 first inserts into the positioning hole 35 set on the bearing plate 8. The positioning rod 25 presses and stabilizes the bearing plate 8, further improving the stability of the bearing plate 8. At the same time, the lower end of the positioning rod 25 is set in a frustum shape. During the process of the positioning rod 25 being inserted into the positioning hole 35, the positioning rod 25 will press the inner wall of the positioning hole 35, which will generate a horizontal compressive force on the bearing plate 8. Fine-tuning the position of the bearing plate 8 is also a specific means to improve the precise fit between the sleeve 6 and the screw 3.

[0029] Reference Figure 3 , Figure 7 and Figure 8 Each sleeve 6 is connected to a negative pressure pipe 26, which extends upward through the support plate 24, and a sleeve 27 is fitted at the end of the negative pressure pipe 26. An air outlet 28 is opened on the outer wall of the sleeve 27. The air outlet 28 on the sleeve 27 is connected to an external negative pressure device. When the electric wrench 5 moves upward and resets, it drives the negative pressure pipe 26 upward via the support plate 24. The upper end of the negative pressure pipe 26 is misaligned with the air outlet 28. At this time, the inner wall of the sleeve 27 seals the upper end of the negative pressure pipe 26. When the electric wrench 5 moves downward, the negative pressure pipe 26 also moves downward, and the upper end of the negative pressure pipe 26 connects with the air outlet 28. The negative pressure pipe 26 is in a negative pressure state, and the end of the negative pressure pipe 26 is connected to... A hollow ring 34 is fitted onto a hollow shaft at the upper end of the sleeve 6. The upper end of the hollow shaft is connected to the output end of the electric wrench 5, and the lower end of the hollow shaft is connected to the sleeve 6. The hollow shaft is connected to the inner ring of the ring 34, and the hollow part of the shaft axis is connected to the inside of the sleeve 6. That is, the negative pressure pipe 26 is connected to the inside of the sleeve 6. The sleeve 6 can attract and hold the end of the screw 3. This is suitable for the attraction and fixation of non-magnetic screws 3, and will not have a negative impact on magnetic screws 3.

[0030] Reference Figure 3 , Figure 7 and Figure 8 Each sleeve 6 has a receiver 29 on its outer side wall; an infrared transmitter 30 is provided on the industrial machine frame 1 at a position opposite to the receiver 29; The infrared transmitter 30 and receiver 29 work together to control the angle of the sleeve 6 for pre-adjustment. When the sleeve 6 is tightened after the screw 3 is turned, the sleeve 6 moves upward and resets. The receiver 29 on the sleeve 6 is aligned with the infrared transmitter 30. Then, the electric wrench 5 drives the sleeve 6 to rotate slowly. When the receiving surface of the receiver 29 is aligned with the emitting end surface of the infrared transmitter 30, the infrared emitted by the infrared transmitter 30 is emitted onto the receiver 29. Then, the control system controls the electric wrench 5 to stop rotating. At this time, each surface of the inner wall of the sleeve 6 is parallel to each side wall of the end of the screw 3, further improving the precise fit between the sleeve 6 and the screw 3.

[0031] Reference Figure 3 , Figure 10 and Figure 12 The lower surface of the support plate 8 is symmetrically provided with guide grooves 31 on both sides; the bottom upper surface of the support plate 7 is provided with guide wheels 32; The support plate 8 slides onto the support plate 7, while the guide wheel rolls in the guide groove 31, converting the sliding friction between the support plate 8 and the support plate 7 into rolling friction between the guide wheel 32 and the support plate 7, further improving the smoothness of the movement of the support plate 8 on the support plate 7. At the same time, a recess 33 is opened on the inner wall of the guide groove 31, and the inner wall of the recess 33 is smoothly transitioned with the inner wall of the guide groove 31. When the support plate 8 moves onto the support plate 7, the guide wheel 32 moves from the guide groove 31 into the recess 33, and the guide wheel slides into the recess 33, indicating that the support plate 8 has moved into place.

[0032] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. An automatic screw tightening robot for an automobile assembly line, characterized in that: It includes an industrial machine frame, which comprises a frame with multiple electric wrenches that move up and down, and each electric wrench has a socket connected to the output end for tightening screws. The industrial machine frame has symmetrical support plates on both sides of its bottom. A bearing plate is slidably connected to the support plate. The bearing plate has multiple positions for positioning screws. Each position includes two symmetrical sliding grooves that penetrate the bearing plate. An oblong hole is opened between two adjacent sliding grooves. A sliding plate is set below the bearing plate, opposite to the oblong hole. The sliding plate is slidably connected to the sliding groove. The sliding plate has a placement hole and a clearance hole. The diameter of the placement hole is smaller than that of the clearance hole, and the placement hole is connected to the adjacent clearance hole.

2. The automatic screw tightening robot for an automobile assembly line according to claim 1, characterized in that: The support plate is provided with a positioning component below it, and the positioning component includes two positioning servo motors. Each servo motor has a pressing plate fixed to its output end. The end of the pressing plate is arc-shaped. The two adjacent pressing plates deflect synchronously to press the screw into the placement hole.

3. The automatic screw tightening robot for an automobile assembly line according to claim 2, characterized in that: Each of the placement holes has an arc-shaped extension plate at its lower edge. The extension plate is positioned away from the clearance hole and, together with two adjacent compression plates, securely wraps around the screw.

4. The automatic screw tightening robot for an automobile assembly line according to claim 3, characterized in that: Each of the waist-shaped holes is provided with a sliding hole on one side, the sliding hole is connected to the waist-shaped hole, the sliding hole is arranged parallel to the two adjacent sliding grooves, and a top plate is provided in the sliding hole. The top plate is fixed to the sliding plate and close to the placement hole. The top plate is used to press against the side wall of the screw end.

5. The automatic screw tightening robot for an automobile assembly line according to claim 4, characterized in that: The lower surface of the bearing plate is equipped with a vibration motor. The extrusion plate applies extrusion force to the screw. The vibration generated by the vibration motor causes the screw to be pressed tightly against the inner wall of the extension plate, and the side wall of the screw end is attached to the end face of the top plate.

6. The automatic screw tightening robot for an automobile assembly line according to claim 1, characterized in that: Multiple No. 1 rollers are provided on the vertical sidewalls of the pallet, and multiple No. 2 rollers are provided on the top lower surface of the pallet. The No. 1 rollers press against the two side walls of the support plate, and the No. 2 rollers press against the upper surface of the support plate.

7. The automatic screw tightening robot for an automobile assembly line according to claim 1, characterized in that: The electric wrench has a support plate on its outer casing, and a positioning rod is slidably connected to the support plate. The upper end of the positioning rod is connected to the support plate by a spring.

8. The automatic screw tightening robot for an automobile assembly line according to claim 7, characterized in that: Each of the sleeves is connected to a negative pressure pipe, which extends upward through the support plate, and a sleeve is fitted at the end of the negative pressure pipe, with an air outlet on the outer wall of the sleeve.

9. The automatic screw tightening robot for an automobile assembly line according to claim 4, characterized in that: A receiver is provided on the outer wall of each sleeve; an infrared transmitter is provided on the industrial machine frame at a position opposite to the receiver.

10. The automatic screw tightening robot for an automobile assembly line according to claim 6, characterized in that: The lower surface of the support plate has symmetrical guide grooves on both sides; the bottom upper surface of the tray is provided with guide wheels.

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