Automatic screwing module for screw assembly

Abstract

The application discloses an automatic screw tightening module for screw assembly, which comprises a stroke assembly, a gun head assembly, a screw suction pipe, a tightening part and a driving mechanism. The stroke assembly has a driving end and a tightening end arranged oppositely. The gun head assembly comprises a gun head seat, a swing arm seat, a screw feeding part, a clamp and an opening and closing part. The gun head seat has a screw suction cavity and one end of the gun head seat is a screw outlet end. The swing arm seat is fixed on the top surface of the gun head seat. The screw feeding part is clamped on the swing arm seat and the upper end of the screw feeding part is connected with a screw feeding machine. The screw feeding part has a screw feeding cavity. The clamp clamps and positions a screw. The opening and closing part drives the clamp to open. The screw suction pipe penetrates through the screw suction cavity to adsorb the screw. The tightening part is slidably connected with the stroke assembly and the output end of the tightening part can penetrate through the screw suction pipe. The driving mechanism is fixed on the driving end to drive the screw suction pipe and the tightening part to slide. The automatic screw tightening module has high integration degree, does not need a large number of stacked transmission components, pneumatic elements and support structures, has small volume and light weight, and meets the light weight requirement of the equipment.

Description

Technical Field

[0001] This invention relates to the field of automated assembly equipment technology, and more specifically to an automatic tightening module for screw assembly, used in mass production assembly lines for industries such as automotive parts, 3C electronic products, and home appliances. Background Technology

[0002] Screw tightening is a core and fundamental process in industrial product assembly. With the rapid popularization of intelligent manufacturing and automated assembly technologies, traditional manual tightening, due to its low efficiency, poor torque consistency, high labor costs, and susceptibility to missed tightening and loose screws, has been gradually replaced by automated screw feeding and tightening equipment. Automatic screw feeding and tightening systems, with their advantages of automatic feeding, automatic alignment, and precise torque control, are widely used in the mass production assembly of various precision parts. As the core executing component of this system, the tightening equipment's structural weight, integration, movement flexibility, and operational accuracy directly determine the assembly efficiency, adaptability, and operational stability of the entire system.

[0003] However, the tightening devices in existing automatic nail feeding and tightening equipment still have the following shortcomings:

[0004] Firstly, the large size and weight of the equipment make it poorly compatible with lightweight robots. With the widespread application of collaborative robots in assembly, their limited end-effector load capacity places higher demands on the lightweighting of actuators. Existing general-purpose tightening equipment is bulky and exceeds weight limits, not only increasing the robot's load burden but also restricting its operating space and flexibility. In scenarios such as multi-station dense tightening, assembly in confined spaces, and parallel operation of multiple devices, large-volume equipment is prone to structural interference, has poor layout flexibility, and is difficult to adapt to the needs of miniaturized and integrated production line transformation. Furthermore, the heavy structure experiences significant inertial impact during high-frequency reciprocating motion, easily causing vibration deviations. After long-term operation, this leads to decreased alignment accuracy and torque control offset, resulting in lower product assembly yield and corresponding increases in equipment noise and energy consumption. This problem is becoming increasingly prominent against the backdrop of continuously increasing lightweighting demands in industries such as automotive and aerospace.

[0005] Secondly, the problems of failed screw insertion and misaligned screws are prominent, affecting production line cycle time and reliability. Failed screw insertion and misaligned screws are two common failure modes in the automatic screw feeding and tightening process, with different causes: misaligned screws mainly stem from insufficient positioning accuracy of the screw head clamp, resulting in initial tilting of the screw while clamped, or the screw head clamp being passively opened, requiring the screw or screw suction tube to push it open, thus causing misalignment; failed screw insertion is mainly due to dimensional and positional tolerances in the incoming workpiece (such as deviations between the through-hole and threaded bottom hole positions in stamped parts), coupled with rigid alignment of the screw head and lack of radial tolerance, leading to a hard misalignment between the screw cutting edge and the workpiece hole wall. Taking the automated assembly of body-in-white doors and hoods as an example, the large size and complex curved surfaces of body components make these problems particularly prominent, resulting in a high tightening failure rate and severely impacting production line cycle time and system reliability.

[0006] Third, the structure is complex and maintenance is inconvenient. Existing tightening equipment has a complex structure, is cumbersome to disassemble and maintain, and is difficult to repair and replace after parts wear out, resulting in high equipment operation and maintenance costs. The installation, commissioning and production stages rely on repeated adjustments by professional personnel, which is time-consuming and labor-intensive; when multiple systems are combined, the commissioning cycle is even longer, and once a failure occurs during production, troubleshooting and downtime will seriously affect the production line rhythm.

[0007] Therefore, there is an urgent need for a lightweight tightening device that has high structural integration, light weight, and small size, while ensuring tightening accuracy and structural strength, and is suitable for high-speed and precision assembly in multiple scenarios. Summary of the Invention

[0008] In view of this, the present invention provides an automatic tightening module for screw assembly, which aims to solve the problem that existing tightening equipment, in pursuit of comprehensive functions, stacks a large number of transmission components, pneumatic components and support structures, resulting in an overall large size and excessive weight.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: An automatic tightening module for screw assembly includes: A stroke assembly having a drive end and a tightening end arranged opposite each other along its stroke direction; A screwdriver head assembly includes a screwdriver head seat, a swing arm seat, a screw feeder, a clamp, and an opening / closing part. The screwdriver head seat is detachably connected to the tightening end and has a screw-collecting cavity along the stroke direction, with the end of the screw-collecting cavity away from the stroke assembly being the screw-out end. The swing arm seat is fixed to the top surface of the screwdriver head seat and has an assembly cavity inclined along the stroke direction. The screw feeder is engaged within the assembly cavity and its upper end is connected to a screw feeder. The screw feeder has a screw-feeding cavity for transmitting screws to the screw-collecting cavity. The clamp is hinged to the screw-feeding end to clamp and position the screw. The opening / closing part is fixed to the bottom surface of the screwdriver head seat and drives the clamp to open and release the screw. A nail suction tube, which is slidably connected to the stroke assembly along the stroke direction and can pass through the nail suction cavity to attract the screw and deliver it to the nail outlet end; A tightening part is slidably connected to the stroke assembly along the stroke direction, and its output end can pass through the nail suction tube and drive the screw to perform a tightening operation; A drive mechanism is fixed to the drive end to drive the suction tube and the tightening part to slide.

[0010] The beneficial effects of the technical solution of the present invention are that the gun head, drive mechanism and tightening part are integrated into a stroke component, the structure is more compact, and compared with the existing screw tightening equipment, there is no need to stack a large number of transmission parts, pneumatic components and support structures, the size is smaller and the weight is lighter, which meets the requirements of lightweight equipment.

[0011] Preferably, the nail feeding part includes a connecting sleeve and a nail feeding tube; the top surface of the gun head seat corresponding to the nail dispensing end has a swing groove; the connecting sleeve is snapped into the assembly cavity; the upper end of the nail feeding tube is inserted into the inner cavity of the connecting sleeve and hinged to the inner wall of the connecting sleeve by a pin, and the lower end is inserted into the swing groove; the sliding of the nail suction tube can touch the lower end of the nail feeding tube to make it swing up and down to perform nail storage and nail feeding actions. The nail feeding tube can store a screw in advance. When the nail suction tube moves to the tightening end, it will push the nail feeding tube upward, and the screw in the nail feeding tube will not enter the nail suction cavity. After the current screw is tightened, the nail suction tube retracts to reset the nail feeding tube, and the next screw is fed into the nail suction cavity. There is no need to wait for the nail feeding machine to respond and the pipeline to deliver the screw. The traditional serial process of tightening → resetting → nailing → nail feeding is optimized into parallel execution, and the time for supplying a single screw is significantly reduced.

[0012] Preferably, it further includes a connecting flange, a nail insertion tube, a locking element, and a resilient reset element; one end face of the connecting flange abuts against the upper end face of the swing arm seat, and the upper end of the connecting sleeve abuts against the inner wall of the connecting flange; the upper end of the nail insertion tube is connected to the nail feeder, and the lower end is inserted into the connecting sleeve and correspondingly communicates with the inner cavity of the nail feeder to form the nail feeder cavity; the locking element is screwed onto the outer wall of the nail insertion tube and abuts against the other end face of the connecting flange, and one end of the locking element is located between the connecting flange and the nail insertion tube; the locking screw passes through the circumferential surface of the connecting flange to fasten the connecting flange, the locking element, and the nail insertion tube; the upper end face of the nail feeder has an inclined swing clearance surface, one end of the resilient reset element is fixed to the lower end face of the nail insertion tube, and the other end abuts against the swing clearance surface to drive the nail feeder to reset after the nail suction tube retracts. During the tightening process, the lower end of the feeding tube swings upward, and the swing avoidance surface forms a misalignment with the axis of the insertion tube. The screw will not enter the feeding tube inside the insertion tube. When the tightening is completed and the suction tube retracts, the elastic reset component drives the feeding tube to reset, and the screw slides into the suction cavity, realizing continuous tightening operation.

[0013] Preferably, the gun head assembly further includes a quick-release screw feeder, which includes a button and a locking post. The outer wall of the swing arm seat has a locking groove extending through its upper end face, and a through hole is formed in the bottom wall of the groove perpendicular to the locking groove. The outer circumferential surface of the connecting flange has a groove corresponding to the locking groove. The middle part of the button is hinged to the locking groove, and one end of the button can be placed in the groove. The locking post is fixed to the other end of the button and can slide axially along the through hole. When a screw jamming failure occurs, the entire screw feeder can be disassembled from the swing arm seat by pressing the button, achieving quick troubleshooting. Different types of screw feeders can be replaced to meet the tightening requirements of different screw models.

[0014] Preferably, the travel assembly includes a base plate, a mounting plate, a mounting seat, a guide shaft, and a differential spring; the mounting plate and the mounting seat are coaxially slidably connected to the top surface of the base plate, and the mounting seat is arranged corresponding to the tightening end; one end of the guide shaft is fixed to the side wall of the mounting seat, and the other end slides through the mounting plate; the differential spring is sleeved on the guide shaft, and its two ends abut against the opposite side walls of the mounting plate and the mounting seat, respectively; the tightening part includes a tightening head and a screwdriver bit; the tightening head is vertically fixed to the side surface of the mounting plate away from the mounting seat, the tail of the screwdriver bit is rotatably connected to the end of the tightening head, and the head is inserted into the nail-collecting tube. The tightening head and the nail-collecting tube are installed through the mounting plate and the mounting seat, and the synchronous and relative movement of the mounting plate and the mounting seat is achieved by the guide shaft and the differential spring.

[0015] Preferably, a slide rail is fixed on the top surface of the base plate; a slider adapted to the slide rail is fixed on the bottom surface of both the mounting plate and the mounting seat; the driving mechanism includes a stroke cylinder and an auxiliary cylinder; the stroke cylinder and the auxiliary cylinder are connected in parallel to the driving end of the base plate; the piston rod of the stroke cylinder is driven to the mounting plate; the auxiliary cylinder is driven to the mounting plate (13) to position and stop the stroke of the mounting plate (13); a limit nut is fixed on the top surface of the base plate corresponding to the tightening end, and the mounting seat can abut against the limit nut. The stroke cylinder is used to drive the sliding of the tightening head and the nail suction tube, the stroke is controlled by the auxiliary cylinder, and the nail suction tube is positioned and stopped at the preset nail suction position according to the working conditions. When the mounting seat touches the limit nut, the mounting plate can continue to slide along the guide shaft and compress the differential spring to ensure the smooth tightening operation.

[0016] Preferably, the mounting base includes a lower base, an upper base, a second button, and a second retaining post. The slider is fixed to the bottom surface of the lower base, and a pressing groove penetrating its upper end surface is formed on the side wall of the lower base. The upper base is engaged with the top surface of the lower base by a retaining pin. The upper base has a through hole corresponding to the nail suction cavity, and a second locking groove communicating with the pressing groove is formed on its side wall. A blind hole is formed on the bottom wall of the second locking groove perpendicular to it. The middle part of the second button is hinged to the second locking groove, and its lower end can be placed in the pressing groove. The second retaining post is fixed to the upper end of the second button and can slide along the axial direction of the blind hole. When nail jamming, material blockage, or other abnormalities occur, the upper base can be quickly disassembled by pressing the second button, greatly shortening downtime. When the production line switches to different specifications of screws, matching parts can be quickly replaced, achieving product switching within minutes, significantly reducing the maintenance cost throughout the equipment's life cycle.

[0017] Preferably, the nail-collecting tube includes a tube body, an end sleeve, and a flexible bushing; the end sleeve is fixed to one end of the tube body and embedded in the upper seat; the flexible bushing is engaged in the nail-collecting cavity, and the outer wall of the tube body slides against the inner wall of the flexible bushing. By setting the flexible bushing, the nail-collecting tube achieves flexible self-alignment, providing precise positioning during the capping stage and adaptive radial compensation based on the actual position of the threaded hole during the insertion stage, effectively avoiding rigid contact and insertion failure caused by workpiece hole position deviation.

[0018] Preferably, the travel assembly further includes a gun head mounting base, which includes a fixing plate, a positioning sleeve, steel balls, a flexible sleeve, and a pull sleeve. The fixing plate is fixed to the tightening end, and a positioning hole is formed on its surface. The positioning sleeve is embedded in the positioning hole. Multiple steel balls are rolled and connected to the circumference of the positioning sleeve. A connecting tube is fixed to the side of the gun head base away from its tightening end. The connecting tube is inserted into the positioning sleeve, and its outer wall has a ball groove for accommodating the steel balls. The flexible sleeve is slidably fitted onto the outer wall of the positioning sleeve. The pull sleeve is fixed to the outer wall of the flexible sleeve to drive the flexible sleeve to slide, thereby securing the positioning sleeve to the connecting tube. The cooperation of the pull sleeve, flexible sleeve, and steel balls enables quick assembly and disassembly of the gun head assembly.

[0019] Preferably, the clamp includes a clamp seat, clamping flaps, and rollers; the clamp seat is engaged with the tightening end; there are two clamping flaps, one end of which is hinged to the end of the clamp seat away from the gun head seat via a hinge shaft; the rollers are rotatably connected to the bottom surface of the clamping flaps; the opening and closing part includes an opening and closing cylinder and a V-shaped guide block; the opening and closing cylinder is fixed to the bottom surface of the gun head seat; the V-shaped guide block is drivenly connected to the piston rod of the opening and closing cylinder, and the inclined surfaces on both sides of the V-shaped guide block can abut against the outer walls of the two rollers. The opening and closing cylinder enables the active opening of the clamping flaps. When the screw is fed onto the clamping flaps, the closed clamping flaps provide reliable support, preventing the screw from breaking open and falling out, thus ensuring stability and reliability during the screw feeding and clamping flap positioning process.

[0020] As can be seen from the above technical solution, compared with the prior art, the present invention discloses an automatic tightening module for screw assembly, which has the following beneficial effects: 1. By compactly redesigning the main structure, transmission path, and air circuit layout of the tightening module, the overall weight and volume are significantly reduced while ensuring functional integrity. It can be smoothly mounted on the end effector of collaborative robots or small six-axis industrial robots with limited load capacity, serving as a highly flexible execution terminal to complete multi-angle, multi-station mobile tightening operations. It is particularly suitable for flexible production scenarios with limited space and where a single robot sequentially tightens multiple screws at different positions, significantly expanding the deployment boundaries of automated tightening equipment.

[0021] 2. While maintaining a compact structure and lightweight design, the integrated screw storage function allows the screw feeder to pre-load the next screw into the screw inlet tube during the previous workstation's operation. This eliminates the need to wait for complete resetting, optimizing the sequential tightening → resetting → screwing → screw feeding process into parallel execution, effectively reducing the time required to supply a single screw. This feature is particularly suitable for high-volume, continuous assembly scenarios with tight cycle times, such as new energy battery production lines and home appliance assembly lines, achieving increased production capacity without increasing equipment footprint or robot load.

[0022] 3. The operation mode adopts the active opening of the clamping flap and the negative pressure suction tube to attract the screw and extend it above the target threaded hole. During the screw extension process, the screw has no contact with the clamping flap, which completely avoids the posture tilting problem caused by the screw pushing open the clamping flap when it extends.

[0023] 4. A radially flexible bushing is installed in the screw-collecting tube, enabling it to adapt to radial displacement when in contact with the workpiece surface. When the incoming workpiece has a deviation in the position of the threaded hole due to stamping, welding deformation, or other factors, the screw-collecting tube can make a slight radial offset to follow the actual hole position at the moment the screw enters the hole, guiding the screw smoothly into the hole and effectively avoiding the failure to enter the hole caused by the hard-on-hard contact of traditional rigid structures. This function is particularly suitable for the assembly of large-sized stamped and welded parts such as automotive body panels and longitudinal beams—these workpieces have large curved surfaces and it is difficult to avoid through-hole positioning deviations. This invention uses flexible self-aligning instead of rigid alignment, significantly improving the success rate of hole entry and ensuring the continuity and stability of production line operation.

[0024] 5. This invention employs a quick-release connection structure, allowing operators to complete rapid component replacement within seconds without the need for specialized tools. On one hand, when abnormalities such as nail jamming or material blockage occur, the corresponding components can be quickly disassembled and cleared, significantly reducing downtime. On the other hand, when switching between different screw specifications on the production line, matching nozzles, nail suction tubes, and bit bits can be quickly replaced, achieving product switching within minutes. This feature is particularly suitable for multi-product mixed-line production scenarios and high-standard manufacturing enterprises that pursue maximum overall equipment efficiency, significantly reducing the equipment's lifecycle maintenance and time costs. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the tightening module structure provided by the present invention; Figure 2 for Figure 1 Enlarged diagram of part A in the diagram; Figure 3 This is a schematic diagram of the stroke component structure provided by the present invention; Figure 4 for Figure 3 Enlarged schematic diagram of part B in the diagram; Figure 5 This is a schematic diagram of the mounting base structure provided by the present invention; Figure 6 A sectional view of the mounting base provided by the present invention; Figure 7 A schematic diagram of the gun head mounting base structure provided by the present invention; Figure 8 A cross-sectional view of the gun head mounting base provided by the present invention; Figure 9This is a schematic diagram of the gun head assembly structure provided by the present invention; Figure 10 This is a cross-sectional view of the gun head assembly provided by the present invention; Figure 11 This is a schematic diagram of the gun head support structure provided by the present invention; Figure 12 This is a schematic diagram of a half-section of the gun head seat provided by the present invention; Figure 13 This is a schematic diagram of the nail feeding part structure provided by the present invention; Figure 14 A cross-sectional view of the nail feeding section provided by the present invention; Figure 15 Exploded view of the nail feeding part provided by the present invention; Figure 16 This is a schematic diagram of the nail feeding tube structure provided by the present invention; Figure 17 This is a cross-sectional view of the quick-release nail feeding component provided by the present invention; Figure 18 This is an assembly structure diagram of the clamp and opening / closing part provided by the present invention; Figure 19 The exploded structure diagram of the clamp provided by this invention; Figure 20 An exploded structural diagram of the opening and closing part provided by the present invention.

[0027] Among them, 1-stroke assembly; 11-base plate; 12-slide rail; 13-mounting plate; 14-mounting seat; 141-lower seat; 142-upper seat; 143-button two; 144-clamp two; 15-guide shaft; 16-gun head mounting seat; 161-fixing plate; 162-pull sleeve; 163-weight reduction hole; 164-positioning sleeve; 165-steel ball; 166-flexible sleeve; 17-limiting nut; 18-slider; 2-Tightening part; 21-Tightening head; 22-Screwdriver bit; 3-Nail suction tube; 31-End sleeve; 32-Flexible bushing; 4-Gunhead assembly; 41-Gunhead seat; 411-Nail suction chamber; 412-Swing groove; 42-Swing arm seat; 43-Nail feeding part; 431-Connecting sleeve; 432-Nail feeding tube; 4321-Swing clearance surface; 433-Nail insertion tube; 434-Connecting flange; 4341-Groove; 435-Locking component; 436-Pin; 437-Elastic reset component; 438-Locking screw; 44-Clamping clamp; 441-Clamping seat; 442-Clamping plate; 443-Hinge shaft; 444-Elastic pin; 445-Roller; 446-Connecting tube; 45-Opening and closing part; 451-Opening and closing cylinder; 452-Cylinder connecting seat; 453-V-shaped guide block; 46-Connecting tube; 47-Nail feeding quick release component; 471-Button 1; 472-Clamping post 1; 48-Locking screw; 5-Drive mechanism; 51-Stroke cylinder; 52-Auxiliary cylinder; 6-Screw. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Existing tightening equipment, in pursuit of comprehensive functionality, excessively stacks transmission components, pneumatic elements, and support structures, resulting in a bulky and heavy overall size, making it difficult to meet the requirements of high dynamic response and narrow space operations. Furthermore, the bloated size easily causes structural interference in scenarios involving multiple devices operating in parallel, confined spaces, and densely packed fastening of precision small parts, leading to poor scenario adaptability. Secondly, existing tightening equipment lacks an active correction mechanism for the screw's posture before tightening. On one hand, the clamping disc positioning accuracy is limited, and the screw in the clamping state already has an initial tilt, making direct pressing and nailing prone to misalignment; on the other hand, workpieces have dimensional and positional tolerances, and the rigid alignment of the screwdriver head lacks radial fault tolerance. When there is a deviation in the position of the threaded hole, the screw cutting edge is rigidly misaligned with the hole wall, directly causing insertion failure and triggering an abnormal torque alarm. Most existing equipment uses a serial control logic of reset first, then screwing. Equipment reset, signal transmission, and screw pneumatic delivery are executed sequentially, which cannot be parallelized. The cumulative time for supplying a single screw makes it difficult to meet high cycle time requirements. In view of this, the present invention discloses an automatic tightening module for screw assembly, which is mainly used in automated assembly production lines and is used in conjunction with an automatic screw feeding system. Its core functions are: receiving screws conveyed by the screw feeder through pipelines, correcting the attitude of the screws and stabilizing them, and accurately conveying the screws to the bottom hole position of the workpiece thread under the drive of the suction tube, and completing the precise tightening according to the preset torque. This realizes the fully automated operation of screws from feeding, attitude adjustment to tightening into the hole, and also features a lightweight structure, stable screw feeding, vertical insertion into the hole and convenient maintenance.

[0030] See appendix Figure 1 To be continued Figure 20According to an embodiment of the present invention, an automatic tightening module for screw assembly includes a stroke assembly 1, a screw head assembly 4, a screw suction tube 3, a tightening part 2, and a drive mechanism 5. The stroke assembly 1 has a drive end and a tightening end arranged opposite to each other along its stroke direction. The screw head assembly 4 includes a screw head seat 41, a swing arm seat 42, a screw feeding part 43, a clamp 44, and an opening and closing part 45. The screw head seat 41 is detachably connected to the tightening end and has a screw suction cavity 411 along the stroke direction, with the end of the screw suction cavity 411 away from the stroke assembly 1 being the screw discharging end. The swing arm seat 42 is fixed to the top surface of the screw head seat 41 and is arranged inclined to the stroke direction. The screw feeding part 43 is engaged with the screw head assembly 5. The feeding chamber 43 is connected to the nail feeder at its upper end. The feeding chamber 43 has a feeding cavity for transmitting the screw 6 to the nail suction chamber 411. The clamp 44 is hinged to the feeding end to clamp the positioning screw 6. The opening and closing part 45 is fixed to the bottom surface of the gun head seat 41 and drives the clamp 44 to open and release the screw. The nail suction tube 3 is slidably connected to the stroke assembly 1 along the stroke direction and can pass through the nail suction chamber 411 to attract the screw 6 and transport it to the nail output end. The tightening part 2 is slidably connected to the stroke assembly 1 along the stroke direction, and its output end can pass through the nail suction tube 3 and drive the screw 6 to perform the tightening operation. The drive mechanism 5 is fixed to the drive end to drive the nail suction tube 3 and the tightening part 2 to slide.

[0031] In this embodiment, the nail feeding part 43 includes a connecting sleeve 431 and a nail feeding tube 432; the top surface of the gun head seat 41 corresponding to the nail discharge end has a swing groove 412; the connecting sleeve 431 is snapped into the assembly cavity; the upper end of the nail feeding tube 432 is inserted into the inner cavity of the connecting sleeve 431 and is hinged to the inner wall of the connecting sleeve 431 by a pin 436, and the lower end is inserted into the swing groove 412; the sliding of the nail suction tube 3 can touch the lower end of the nail feeding tube 432 to make it swing up and down to perform nail storage and nail feeding actions.

[0032] To further optimize the above technical solution, it also includes a connecting flange 434, a nail insertion tube 433, a locking element 435, and an elastic reset element 437; one end face of the connecting flange 434 abuts against the upper end face of the rocker arm seat 42, and the upper end of the connecting sleeve 431 abuts against the inner wall of the connecting flange 434; the upper end of the nail insertion tube 433 is connected to the nail feeder, and the lower end is inserted into the connecting sleeve 431, correspondingly communicating with the inner cavity of the nail feeder tube 432 to form a nail feeding cavity; the locking element 435 is screwed onto the outer wall of the nail insertion tube 433 and connects with the connecting flange 434. The other end face of flange 434 abuts against, and one end of it is located between connecting flange 434 and nail insertion tube 433; locking screw 48 passes through the circumferential surface of connecting flange 434 to fasten connecting flange 434, locking member 435 and nail insertion tube 433; the upper end face of nail feeding tube 432 has an inclined swing relief surface 4321, one end of elastic reset member 437 is fixed to the lower end face of nail insertion tube 433, and the other end abuts against swing relief surface 4321 to drive nail feeding tube 432 to reset after nail suction tube 3 retracts.

[0033] like Figure 10As shown, the connecting sleeve is snapped into the swing arm seat, and the nail feeding tube is connected to the connecting sleeve by a pin to achieve swinging; the outer wall of the nail insertion tube is provided with a convex ring and is inserted into the connecting sleeve; the locking element is a locking nut, one end of which has a convex post, which is inserted into the connecting sleeve and abuts against the convex ring; the connecting flange, connecting sleeve, locking nut and nail insertion tube are fastened together by locking screws to achieve the assembly of the entire nail feeding part.

[0034] like Figures 13 to 16 As shown, both the screw insertion tube and the screw feeding tube are mounted on the swing arm seat. When the screw insertion tube receives the first screw and feeds it into the screw suction chamber through the screw feeding tube, the screw suction tube uses negative pressure to suction the screw and feed it to the screw exit end. During this process, the screw suction tube contacts the screw feeding tube and pushes it upward. The swing avoidance surface compresses the elastic reset member, and an inclined misalignment is formed between it and the screw insertion tube. After the screw insertion tube receives the second screw, the second screw will be stuck at the misalignment. When the tightening operation is completed and the screw suction tube retracts, the elastic restoring force of the elastic reset member forces the screw feeding tube to reset. At this time, the screw feeding tube and the screw insertion tube return to the connected state, and the second screw slides down into the screw suction chamber simultaneously.

[0035] In this embodiment, during the tightening of the first screw, the next screw is pre-loaded into the nail gun tube by the nail feeder and is ready to be fed. Once the first screw is tightened and the nail suction tube is reset, the second screw is already positioned in the nail suction chamber, eliminating the need to wait for the nail feeder to respond or for the tube to deliver the screw. This mechanism optimizes the traditional sequential process of tightening → resetting → nailing → feeding into parallel execution, significantly reducing the time required to supply a single screw.

[0036] To further optimize the above technical solution and facilitate the replacement of the screw feeding part to adapt to different screw models and quickly eliminate faults such as stuck screws, the gun head assembly 4 also includes a screw feeding quick-release component 47, which includes a button 471 and a locking post 472; the outer wall of the swing arm seat 42 is provided with a locking groove 421 that passes through its upper end face, and the bottom wall of the vertical locking groove 421 is provided with a through hole; the outer peripheral surface of the connecting flange 434 is provided with a groove 4341 corresponding to the locking groove; the middle part of the button 471 is hinged to the locking groove 421 by a hinge, and one end of it can be placed in the groove 4341; the locking post 472 is fixed to the other end of the button 471 and can slide along the through hole axially.

[0037] The feeding section and the swing arm seat are engaged via button one and locking post one. For example... Figure 17 As shown, under normal use, button one is located in locking groove one and recess one, while locking post one is located in through hole one; when it is necessary to disassemble the feeding part, press the end of button one away from locking post one, so that the locking post slides out of through hole, releasing the locking relationship between feeding part and swing arm seat, thereby realizing quick disassembly of feeding part.

[0038] In automated nail feeding and tightening operations, nail jamming is one of the most common unexpected malfunctions. During high-speed pneumatic feeding, screws can easily become stuck at bends or transition points in the feeding channel due to posture deviation or size fluctuations. Traditional integrated nail feeding channels require operators to use specialized tools to remove jammed screws, resulting in lengthy and difficult operations that severely impact production line speed. In this embodiment, the nail feeding unit and the swing arm seat employ a quick-release connection structure. When a jamming malfunction occurs, operators do not need any specialized tools; they only need to press to release the axial quick-release limit, allowing the entire nail feeding unit to be detached from the swing arm seat, fully exposing the channel interior and enabling rapid nail removal. After cleaning, the radial precision positioning structure allows for quick reinstallation, ensuring coaxiality between the channel and the nozzle assembly. The entire disassembly and assembly process takes only a few seconds, minimizing the impact of malfunctions on production line speed. Meanwhile, the quick-release structure also facilitates production line changeovers. When switching between different screw specifications, the matching screw feeding part can be quickly replaced, enabling minute-level product switching and further enhancing the equipment's adaptability to mixed production lines with multiple product types.

[0039] In this embodiment, the stroke assembly 1 includes a base plate 11, a mounting plate 13, a mounting base 14, a guide shaft 15, and a differential spring; the mounting plate 13 and the mounting base 14 are coaxially slidably connected to the top surface of the base plate 11, and the mounting base 14 is arranged with the tightening end corresponding to the mounting plate 15; one end of the guide shaft 15 is fixed to the side wall of the mounting base 14, and the other end slides through the mounting plate 13; the differential spring is sleeved on the guide shaft 15, and its two ends abut against the opposite side walls of the mounting plate 13 and the mounting base 14, respectively; the tightening part 2 includes a tightening head 21 and a screwdriver bit 22; the tightening head 21 is vertically fixed to the side plate surface of the mounting plate 13 away from the mounting base 14, the tail of the screwdriver bit 22 is rotatably connected to the end of the tightening head 21, and the head is inserted into the nail suction tube 3.

[0040] To further optimize the above technical solution, a slide rail 12 is fixed on the top surface of the base plate 11; a slider 18 adapted to the slide rail 12 is fixed on the bottom surface of both the mounting plate 13 and the mounting seat 14; the drive mechanism 5 includes a stroke cylinder 51 and an auxiliary cylinder 52; the stroke cylinder 51 and the auxiliary cylinder 52 are connected in parallel at the drive end of the base plate 11; the piston rod of the stroke cylinder 51 is connected to the mounting plate 13 through a floating joint, and the floating joint is used to compensate for the coaxiality deviation during assembly and movement, so as to avoid the piston rod of the stroke cylinder from being jammed due to radial force, and to ensure the smoothness and reliability of the stroke action; the auxiliary cylinder 52 is connected to the mounting plate 13 to position and stop the stroke of the mounting plate 13; a limit nut 17 is fixed on the top surface of the base plate 11 corresponding to the tightening end, and the mounting seat 14 can abut against the limit nut 17.

[0041] like Figures 1 to 4As shown, the auxiliary cylinder and the stroke cylinder are installed in parallel. The two cylinders are arranged side by side and fixed to the drive end of the base plate by a connecting plate, eliminating the redundant connecting brackets and transition plates in the traditional series layout and compressing the module width to the extreme. This compact layout not only significantly reduces the module volume, allowing it to be deployed comfortably in assembly stations with limited space, but also reduces the weight of redundant components from the structural source, laying the foundation for the overall lightweight design. The stroke cylinder can drive the nail suction tube to move linearly, while the auxiliary cylinder realizes stroke control and positions and stops the nail suction tube at the preset nail suction position according to the working conditions.

[0042] In this embodiment, the piston rod of the stroke cylinder is connected to the mounting plate via a floating joint to compensate for coaxiality deviations during assembly and movement, prevent the piston rod from jamming due to radial force, and ensure the smoothness and reliability of the stroke action. The side wall of the mounting plate is detachably connected to an adjusting bolt. The piston of the auxiliary cylinder has a transmission free stroke between its initial position and the adjusting bolt. During operation, the piston rod of the auxiliary cylinder extends to the distance of the transmission free stroke. After the piston rod of the auxiliary cylinder contacts the adjusting bolt, the piston rod of the fixed stroke cylinder extends, thereby driving the linear movement of the mounting plate. At this time, the nail suction tube slides synchronously along the nail suction cavity. The movement of the nail suction tube = the movement of the auxiliary cylinder piston rod - the transmission free stroke. The size of the transmission free stroke is adjusted by adjusting the length or installation position of the adjusting bolt, thereby adjusting the nail suction position of the nail suction tube.

[0043] In this embodiment, the base plate, mounting plate, and mounting base are all made of high-strength aluminum alloy, achieving significant weight reduction while ensuring structural strength. The linear guide rail ensures high-frequency reciprocating motion accuracy and rigidity. The base plate width is controlled at approximately 40mm, and the center height is about 60mm. This low center of gravity design effectively reduces the overturning moment during movement, eliminates vibration deviations caused by the bulky structure, and ensures the stability of alignment accuracy and torque control after long-term operation. This dual optimization of weight reduction and low center of gravity allows the workpiece to be smoothly mounted on the end effector of a collaborative robot, fully responding to users' urgent needs for lightweight robot integration applications.

[0044] In the initial stage of the stroke, the stroke cylinder can drive the mounting plate and the mounting seat to move synchronously. When the mounting seat moves to contact the limit nut, the mounting plate and the mounting seat move relative to each other under the blocking and limiting effect of the limit nut. The mounting plate can compress the spring to ensure smooth tightening of the screwdriver bit.

[0045] The nail suction tube and the screwdriver bit are respectively mounted on the mounting base and the tightening head. In the initial state, the screwdriver bit is retracted inside the nail suction tube; when the screw enters the hole and enters the tightening stage, the screwdriver bit needs to extend relative to the nail suction tube to complete the cap recognition and tightening action with the screw head drive groove. This relative movement is defined as the screwdriver bit differential movement.

[0046] This embodiment utilizes a differential spring between the mounting plate and the mounting base to achieve a differential function. The differential process consists of two stages: the first stage is the synchronous extension stage, before the nail suction tube is mechanically stopped (the mounting base is in contact with the limit nut), the elastic force provided by the differential spring is greater than the frictional resistance during the movement of the nail suction tube, ensuring that the mounting plate and the mounting base remain relatively stationary and move synchronously until the screw is inserted into the hole and mechanically stopped. The second stage is the differential extension stage, after the nail suction tube is stopped (the mounting base contacts the limit nut), the stroke cylinder continues to drive the mounting plate to move, compressing the differential spring to overcome the elastic force, and the screwdriver bit extends relative to the nail suction tube, completing the capping and tightening operation. Compared with traditional pneumatic spring solutions, the mechanical differential spring has significant advantages such as light weight, simple structure, and convenient installation, perfectly matching the lightweight design concept of this module, and reliably achieving the differential function of the screwdriver bit without adding additional pneumatic components.

[0047] To further optimize the above technical solution, the mounting base 14 includes a lower base 141, an upper base 142, a second button 143, and a second locking post 144. A slider 18 is fixed to the bottom surface of the lower base 141, and a pressing groove penetrating its upper end surface is opened on the side wall of the lower base 141. The upper base 142 is engaged with the top surface of the lower base 141 by a locking pin. A through hole corresponding to the suction pin cavity 411 is opened on the upper base 142, and a locking groove 2 communicating with the pressing groove is opened on its side wall. A blind hole is opened on the bottom wall of the locking groove 2 perpendicular to the groove. The middle part of the second button 143 is hinged to the locking groove 2, and its lower end can be placed in the pressing groove. The second locking post 144 is fixed to the upper end of the second button 143 and can slide along the axial direction of the blind hole.

[0048] like Figure 4 and Figure 5 As shown, the mounting base adopts a split structure, using locking pins to achieve precise positioning and docking, ensuring screw tightening accuracy and hole insertion accuracy. The upper and lower bases are quickly disassembled via button two and locking post two. Operators do not need any special tools; simply pressing button two allows for rapid assembly and disassembly of the screw suction tube and bit. In case of screw jamming, material blockage, or other abnormalities, disassembly and cleaning can be performed quickly, significantly reducing downtime. When switching between different screw specifications on the production line, matching components can be quickly replaced, achieving product switching within minutes, significantly reducing the equipment's total lifecycle maintenance costs.

[0049] In this embodiment, the nail suction tube 3 includes a tube body, an end sleeve 31, and a flexible bushing 32; the end sleeve 31 is fixed to one end of the tube body and embedded in the upper seat 142; the flexible bushing 32 is snapped into the nail suction cavity 411, and the outer wall of the tube body slides against the inner wall of the flexible bushing 32.

[0050] The nail suction tube is installed in the gun head seat and upper seat through a flexible bushing and an end sleeve: the end sleeve is embedded in the upper seat to fix the nail suction tube, the flexible bushing is built into the gun head seat, and the nail suction tube passes through the flexible bushing. Its outer diameter is precisely slidingly fitted with the inner hole of the flexible bushing to ensure that the nail suction tube is always concentric with the flexible bushing and floats radially in sync with its radial flexible deformation.

[0051] The screw suction tube picks up the screw near the clamp. In the suction state, the extension of the suction tube is small, and its front end is close to the flexible bushing, resulting in only a tiny radial float ΔS, which ensures high positioning accuracy and precise suction. When the suction tube extends to its maximum stroke to deliver the screw into the hole, its front end moves away from the flexible bushing, and the Abbe error is significantly amplified. Even a tiny radial offset at the flexible bushing can cause the end of the suction tube to have a radial float ΔS′ that is several times larger.

[0052] This design utilizes the Abbe error amplification principle to achieve a flexible self-aligning function at the end of the nail suction tube while maintaining a precise fit between the nail suction tube and the flexible bushing. It provides precise positioning during the cap recognition stage and adaptive radial compensation based on the actual position of the threaded hole during the hole insertion stage, effectively avoiding rigid contact and insertion failure caused by workpiece hole position deviation.

[0053] The closer the flexible bushing is to the clamping side, the more precise the guidance during adsorption; the longer the lever arm after the suction tube extends, the more significant the floating amplification effect, which is more beneficial for large deviations in hole entry conditions. Accuracy at the near end and flexibility at the far end are both achieved in the same floating mechanism without adding any extra components to the structure. This dual function is achieved simply by utilizing the lever ratio in the layout.

[0054] To further optimize the above technical solution, the effective length range of the nail suction tube extending from the clamp is 50 to 150 mm, the radial flexible deformation floating amount of the flexible bushing is ±0.1 to ±0.5 mm, and the actual radial compensation at the end can reach ±1.0 to ±2.0 mm.

[0055] To further optimize the above technical solution, the stroke assembly 1 also includes a gun head mounting base 16, which includes a fixing plate 161, a positioning sleeve 164, steel balls 165, a flexible sleeve 166, and a pull sleeve 162. The fixing plate 161 is fixed to the tightening end, and a positioning hole is provided on its plate surface. The positioning sleeve 164 is embedded in the positioning hole. There are multiple steel balls 165, which are rolled and connected to the circumference of the positioning sleeve 164. A connecting tube 46 is fixed on the side of the gun head seat 41 away from its tightening end. The connecting tube 46 is inserted into the positioning sleeve 164, and its outer wall has a ball groove for accommodating the steel balls 165. The flexible sleeve 166 is slidably sleeved on the outer wall of the positioning sleeve 164. The pull sleeve 162 is fixed to the outer wall of the flexible sleeve 166 to drive the flexible sleeve 166 to slide so that the positioning sleeve 164 is fastened to the connecting tube 46.

[0056] like Figure 6 and Figure 7As shown, after the connecting tube is inserted into the positioning sleeve, the flexible sleeve is driven by the pull sleeve to slide and press the steel column into the ball groove of the connecting tube. To ensure the snap-fit ​​effect, the two hemispheres of the steel column are located on the positioning sleeve and the connecting tube, respectively. The gun head mounting seat adopts a steel ball mechanical quick-locking mechanism to realize quick and accurate positioning and installation and one-click disassembly between the gun head assembly and the stroke assembly, combining connection reliability and operation convenience.

[0057] To further optimize the above technical solution and ensure the lightweight requirement, weight reduction holes 163 are provided on the surface of the fixing plate 161.

[0058] To further optimize the above technical solution, the clamp 44 includes a clamp seat 441, clamping flaps 442, and rollers 445; the clamp seat 441 is engaged with the tightening end; there are two clamping flaps 442, and one end of each flap is hinged to the end of the clamp seat 441 away from the gun head seat 41 via a hinge pin 443; the rollers 445 are rotatably connected to the bottom surface of the clamping flaps 442; the opening and closing part 45 includes an opening and closing cylinder 451 and a V-shaped guide block 453; the opening and closing cylinder 451 is fixed to the bottom surface of the gun head seat 41; the V-shaped guide block 453 is drivenly connected to the piston rod of the opening and closing cylinder 451, and the inclined surfaces on both sides of the V-shaped guide block 453 can abut against the outer walls of the two rollers 445.

[0059] like Figures 17 to 19 The clamp 441 and the gun head seat 41 are connected by an elastic pin 444, which passes through both ends of the clamp 441. The elastic pin 444 includes a pin body, a telescopic spring sleeved on the pin body, and a steel ball fixed to one end of the spring. The steel ball abuts against the end face of the clamp 442 under the preload of the telescopic spring. After the clamp 441 and the gun head seat 41 are assembled, the telescopic spring continuously applies a clamping force to the clamp 442 through the steel ball, providing a self-recovering closing driving force for the clamp 442, ensuring that the clamp 442 remains closed in its initial state. When the screw 6 is fed onto the clamp 442, the closed clamp 442 provides reliable support, and the screw 6 will not break open the clamp 442 and fall off, ensuring the stability and reliability of the screw feeding process to the clamp positioning.

[0060] To further optimize the above technical solution, a connecting pipe 446 is also included. The connecting pipe 446 is fixed inside the clamp 441 and connects the nail suction cavity 411 and the nail feeding tube 432. One end of the connecting pipe 446 is a slope, and the lower end face of the nail feeding tube 432 can slide up and down along the slope to ensure its swinging effect.

[0061] The screw is directly fed into the connecting tube by the screw feed tube, and the gun head holder does not directly contact the screw. Traditionally, the gun head holder is made entirely of steel, requiring high impact resistance and wear resistance because it directly contacts the screw. In this embodiment, the clamp and gun head holder are separate structures. The gun head holder is made of high-strength aluminum alloy, while the clamp is made of steel. While meeting functional requirements, the overall weight of the gun head assembly is reduced by approximately 65%, significantly reducing the load on the front end of the module. This improves the dynamic response performance of the robot's end effector and greatly simplifies the structure, significantly reducing manufacturing difficulty.

[0062] To further optimize the above technical solution, a cylinder connecting seat 452 is also included. The cylinder connecting seat 452 is fixed to the output end of the opening and closing cylinder 451. A guide groove is provided on the cylinder connecting seat 452, and a V-shaped guide block 453 is slidably connected in the guide groove.

[0063] Driven by an opening and closing cylinder, the V-shaped guide block precisely extends and retracts axially along the guide groove. Each of the two clamping petals is equipped with a roller, symmetrically distributed and tangent to the inclined surfaces on both sides of the V-shaped guide block. When the opening and closing cylinder drives the V-shaped guide block to extend axially, the inclined surfaces of the V-shaped guide block push the rollers on both sides to roll synchronously. The rollers cause the two clamping petals to rotate outward around the hinge axis and open, achieving active opening of the clamping petals. When the opening and closing cylinder resets, the V-shaped guide block retracts, and the clamping petals automatically close under the restoring force of the elastic pin.

[0064] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0065] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An automatic tightening module for screw assembly, characterized in that, include: The stroke assembly (1) has a drive end and a tightening end arranged opposite to each other along its stroke direction; The gun head assembly (4) includes a gun head seat (41), a swing arm seat (42), a nail feeding part (43), a clamp (44), and an opening and closing part (45); the gun head seat (41) is detachably connected to the tightening end and has a nail suction cavity (411) along the stroke direction, the end of the nail suction cavity (411) away from the stroke assembly (1) being the nail discharging end; the swing arm seat (42) is fixed to the top surface of the gun head seat (41) and has an assembly cavity arranged at an inclination along the stroke direction; the nail feeding part (43) is engaged in the assembly cavity and its upper end is connected to a nail feeder, the nail feeding part (43) having a nail feeding cavity for transmitting screws (6) to the nail suction cavity (411); the clamp (44) is hinged to the nail feeding end to clamp and position the screws (6); the opening and closing part (45) is fixed to the bottom surface of the gun head seat (41) and drives the clamp (44) to open and release the screws; The nail suction tube (3) is slidably connected to the stroke assembly (1) along the stroke direction and can penetrate the nail suction cavity (411) to attract the screw (6) and deliver it to the nail outlet end; Tightening part (2), the tightening part (2) is slidably connected to the stroke assembly (1) along the stroke direction, and its output end can pass through the suction tube (3) and drive the screw (6) to perform tightening operation; The driving mechanism (5) is fixed to the driving end to drive the suction tube (3) and the tightening part (2) to slide.

2. The automatic tightening module for screw assembly according to claim 1, characterized in that, The nail feeding part (43) includes a connecting sleeve (431) and a nail feeding tube (432); the gun head seat (41) has a swing groove (412) on the top surface corresponding to the nail dispensing end; the connecting sleeve (431) is snapped into the assembly cavity; the upper end of the nail feeding tube (432) is inserted into the inner cavity of the connecting sleeve (431) and hinged to the inner wall of the connecting sleeve (431) by a pin (436), and the lower end is inserted into the swing groove (412); the sliding of the nail suction tube (3) can touch the lower end of the nail feeding tube (432) to make it swing up and down to perform nail storage and nail feeding actions.

3. An automatic tightening module for screw assembly according to claim 2, characterized in that, It also includes a connecting flange (434), a nail insertion tube (433), a locking element (435), and a resilient reset element (437); one end face of the connecting flange (434) abuts against the upper end face of the rocker arm seat (42), and the upper end of the connecting sleeve (431) abuts against the inner wall of the connecting flange (434); the upper end of the nail insertion tube (433) is connected to the nail feeder, and the lower end is inserted into the connecting sleeve (431) and correspondingly connected to the nail feeder (437). 2) The inner cavity forms the nail feeding cavity; the locking member (435) is screwed onto the outer wall of the nail insertion tube (433) and abuts against the other end face of the connecting flange (434), and one end of it is located between the connecting flange (434) and the nail insertion tube (433); the locking screw (48) passes through the circumferential surface of the connecting flange (434) to fasten the connecting flange (434), the locking member (435) and the nail insertion tube (433); The upper end face of the feeding tube (432) has an inclined swing avoidance surface (4321). One end of the elastic reset member (437) is fixed to the lower end face of the insertion tube (433), and the other end abuts against the swing avoidance surface (4321) to drive the feeding tube (432) to reset after the suction tube (3) retracts.

4. An automatic tightening module for screw assembly according to claim 3, characterized in that, The gun head assembly (4) also includes a quick-release nail feeder (47), which includes a button (471) and a locking post (472). The outer wall of the swing arm seat (42) is provided with a locking groove (421) that passes through its upper end face, and a through hole is provided on the bottom wall of the groove perpendicular to the locking groove (421). The outer peripheral surface of the connecting flange (434) is provided with a groove (4341) corresponding to the locking groove. The middle part of the button (471) is hinged to the locking groove (421) by a hinge, and one end of the button can be placed in the groove (4341). The locking post (472) is fixed to the other end of the button (471) and can slide along the through hole axially.

5. An automatic tightening module for screw assembly according to any one of claims 1 to 4, characterized in that, The stroke assembly (1) includes a base plate (11), a mounting plate (13), a mounting seat (14), a guide shaft (15), and a differential spring; the mounting plate (13) and the mounting seat (14) are coaxially slidably connected to the top surface of the base plate (11), and the mounting seat (14) is arranged corresponding to the tightening end; one end of the guide shaft (15) is fixed to the side wall of the mounting seat (14), and the other end slides through the mounting plate (13); the differential spring is sleeved on the guide shaft (15), and its two ends abut against the opposite side walls of the mounting plate (13) and the mounting seat (14), respectively; The tightening part (2) includes a tightening head (21) and a bit (22); the tightening head (21) is vertically fixed on the side of the mounting plate (13) away from the mounting base (14), the tail of the bit (22) is rotatably connected to the end of the tightening head (21), and the head is inserted into the nail suction tube (3).

6. An automatic tightening module for screw assembly according to claim 5, characterized in that, The top surface of the base plate (11) is fixed with a slide rail (12); the bottom surfaces of the mounting plate (13) and the mounting base (14) are both fixed with sliders (18) that are adapted to the slide rail (12). The drive mechanism (5) includes a stroke cylinder (51) and an auxiliary cylinder (52); the stroke cylinder (51) and the auxiliary cylinder (52) are connected in parallel to the drive end of the base plate (11); the piston rod of the stroke cylinder (51) is driven to the mounting plate (13); the auxiliary cylinder (52) is driven to the mounting plate (13) to position and stop the stroke of the mounting plate (13); The base plate (11) has a limit nut (17) fixed on the top surface corresponding to the tightening end, and the mounting seat (14) can abut against the limit nut (17).

7. An automatic tightening module for screw assembly according to claim 6, characterized in that, The mounting base (14) includes a lower base (141), an upper base (142), a second button (143), and a second locking post (144). The slider (18) is fixed to the bottom surface of the lower base (141), and a pressing groove penetrating its upper end surface is opened on the side wall of the lower base (141). The upper base (142) is snapped onto the top surface of the lower base (141) by a locking pin. A through hole corresponding to the suction pin cavity (411) is opened on the upper base (142), and a locking groove two communicating with the pressing groove is opened on its side wall. A blind hole is opened on the bottom wall of the groove perpendicular to the locking groove two. The middle part of the second button (143) is hinged to the locking groove two, and its lower end can be placed in the pressing groove. The second locking post (144) is fixed to the upper end of the second button (143) and can slide along the axial direction of the blind hole.

8. An automatic tightening module for screw assembly according to claim 7, characterized in that, The nail suction tube (3) includes a tube body, an end sleeve (31) and a flexible bushing (32); the end sleeve (31) is fixed to one end of the tube body and embedded in the upper seat (142); the flexible bushing (32) is engaged in the nail suction cavity (411), and the outer wall of the tube body slides against the inner wall of the flexible bushing (32).

9. An automatic tightening module for screw assembly according to claim 1, characterized in that, The stroke assembly (1) further includes a gun head mounting base (16), which includes a fixing plate (161), a positioning sleeve (164), steel balls (165), a flexible sleeve (166), and a pull sleeve (162); the fixing plate (161) is fixed to the tightening end, and a positioning hole is provided on its plate surface; the positioning sleeve (164) is embedded in the positioning hole; the number of steel balls (165) is multiple and they are rolled on the circumference of the positioning sleeve (164); the gun A connecting tube (46) is fixed on the side of the headstock (41) away from its tightening end. The connecting tube (46) is inserted into the positioning sleeve (164), and its outer wall is provided with a ball groove for accommodating the steel ball (165). The flexible sleeve (166) is slidably sleeved on the outer wall of the positioning sleeve (164). The pull sleeve (162) is fixed on the outer wall of the flexible sleeve (166) to drive the flexible sleeve (166) to slide so that the positioning sleeve (164) is fastened to the connecting tube (46).

10. An automatic tightening module for screw assembly according to claim 1, characterized in that, The clamp (44) includes a clamp seat (441), clamping flaps (442), and rollers (445); the clamp seat (441) is engaged with the tightening end; there are two clamping flaps (442), one end of which is hinged to the end of the clamp seat (441) away from the gun head seat (41) via a hinge pin (443); the rollers (445) are rotatably connected to the bottom surface of the clamping flaps (442); The opening and closing part (45) includes an opening and closing cylinder (451) and a V-shaped guide block (453); the opening and closing cylinder (451) is fixed to the bottom surface of the gun head seat (41); the V-shaped guide block (453) is connected to the piston rod of the opening and closing cylinder (451) in a transmission manner, and the inclined surfaces on both sides of the V-shaped guide block (453) can abut against the outer walls of the two rollers (445).

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