A defect detection apparatus for automotive fastener production

Abstract

The application discloses a kind of defect detection equipment for automobile fastener production, belong to fastener production detection technical field.The equipment includes fastener transmission table, detection mechanism and transmission support.Detection mechanism is arranged between two sections of conveyor belt, and the inner wall two sides are respectively provided with eccentric cam of gear drive and driving friction wheel.Transmission support two sides are fixed with driving rack, and when conveying moves, two sides gear are synchronously driven to rotate, and then drive fastener to complete self-rotation and swing synchronously, cooperate imaging assembly to complete surface defect detection.The equipment can realize two degrees of freedom detection posture adjustment without independent driving motor, compact structure, transmission is stable, effectively improve the detection precision and operation reliability of automobile fastener thread defect, reduce equipment cost and maintenance difficulty.

Description

Technical Field

[0001] This invention relates to the field of fastener production and inspection technology, and specifically to a defect detection device for automotive fastener production. Background Technology

[0002] In the manufacturing process of automotive parts, fasteners such as bolts and screws are core connecting components. Defects such as cracks, breaks, and missing threads on their surfaces directly affect the connection strength of the entire vehicle assembly and driving safety. Therefore, comprehensive surface defect inspection must be carried out before leaving the factory. Currently, the industry generally uses fixed-position machine vision inspection to screen for surface defects in fasteners, using optical imaging combined with image recognition algorithms to determine the presence of defects.

[0003] In conventional fixed-view visual inspection schemes, fastener threads have a helical, convex-concave structure. Under fixed shooting angles and lighting conditions, the raised parts of the thread profile physically block the recessed areas at the root of the thread. These deep recesses cannot be fully illuminated and cannot fully enter the camera's field of view, creating a large, continuous blind spot. Micro-cracks, surface defects, and minor corrosion at the thread root are completely hidden within this blind spot, making them difficult to identify using conventional inspection methods, resulting in a high rate of missed detections and failing to meet the high-precision quality control requirements of automotive fasteners. Furthermore, existing inspection equipment often uses independent drive mechanisms to adjust the workpiece's posture, resulting in a complex overall structure. Deploying electronic control components in a closed inspection environment presents challenges in heat dissipation and dust prevention, leading to high failure rates and maintenance costs during long-term continuous operation, making it difficult to adapt to the long-term stable operation requirements of automotive fastener mass production lines.

[0004] Therefore, there is an urgent need for a defect detection device for automotive fastener production that can effectively cover the threaded recessed area, eliminate blind spots in detection, have high detection accuracy, and be suitable for continuous operation of mass production lines. Summary of the Invention

[0005] The present invention aims to solve the problems of large blind zone, high missed detection rate, complex structure and poor operation reliability of existing fastener defect detection equipment, and provides a defect detection equipment for automotive fastener production.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A defect detection device for automotive fastener production includes a fastener transmission table, a detection mechanism, and a conveyor support assembly. The fastener transmission table includes a frame body, a first conveyor belt, and a second conveyor belt. The detection mechanism is installed between the first and second conveyor belts and includes an imaging component. A drive rack is installed on the inner wall of the detection mechanism. The conveyor support assembly is mounted on the frame body and includes a conveyor support. A support member is connected to the conveyor support via a rotating shaft. Several guide wheels are installed on the support member. The nut head of the fastener is positioned above the guide wheels. A first gear and an eccentric cam are installed on one side of the conveyor support. The transmission bracket is connected by a cam drive. A second gear and a driving friction wheel are installed on the other side of the transmission bracket. The second gear and the driving friction wheel are connected by a drive mechanism. The first gear and the second gear are driven by the drive rack. A swing arm drive wheel is fixed to the outer end of the rotating shaft. The swing arm drive wheel abuts against the outer peripheral surface of the eccentric cam. A return spring is provided between the transmission bracket and the swing arm drive wheel. A driven friction wheel is connected to the outer end of the support member. The driven friction wheel has a driving synchronous pulley. The guide wheel is fixed with a driven synchronous pulley. The driving synchronous pulley and the driven synchronous pulley are driven by a synchronous belt. When the transmission bracket assembly is fed to the work station, the driven friction wheel and the end face of the driving friction wheel are axially pressed together.

[0007] Furthermore, the contact surfaces of the eccentric cam and the swing arm drive wheel are inclined surfaces, and the eccentric cam is provided with an eccentrically arranged waist-shaped hole, which is connected to the first gear drive by a tightening screw.

[0008] Furthermore, the conveyor support assembly also includes a drive belt, the conveyor support is mounted on the drive belt, and the drive belt is mounted on the frame body via rollers.

[0009] Furthermore, the swing arm drive wheel is a helical gear structure, and the outer side of the eccentric cam is provided with a tooth structure that matches the gear of the swing arm drive wheel.

[0010] Furthermore, the waist-shaped hole is provided with an adjusting threaded hole along its long axis, and the tightening screw is fixedly connected inside the waist-shaped hole through the adjusting threaded hole.

[0011] Furthermore, the contact surface between the active friction wheel and the driven friction wheel is an inclined surface and is covered with a rubber wear-resistant layer.

[0012] Furthermore, a tensioning wheel is rotatably mounted on the conveyor support, the wheel body of the tensioning wheel abuts against the timing belt, and a waist-shaped adjustment hole is provided at the position of the conveyor support where the mounting seat of the tensioning wheel is located.

[0013] Furthermore, the eccentricity e of the eccentric cam, the effective swing length L of the swing arm drive wheel and the swing angle α satisfy the relationship: α=2・arcsin(e / L); and the swing angle α matches the thread parameters of the fastener to be tested, satisfying α≥2・arctan(h / P), where h is the thread depth and P is the thread pitch.

[0014] Furthermore, the surfaces of the two guide wheels are provided with silicone sleeves.

[0015] Furthermore, the support member of the conveyor bracket is provided with a magnetic block for attracting the fasteners on the first conveyor belt into the support member.

[0016] Furthermore, at least one set of ion nozzles is installed on the feed side wall of the detection mechanism. The air outlet direction of the ion nozzles is towards the fastener thread area entering the workstation, and the air outlet angle of the ion nozzles can be adjusted by the hinge seat. Beneficial effects

[0017] 1. It adopts mechanical rack and pinion transmission to synchronously drive the dual action of rotation and oscillation, eliminating the need for an independent drive motor and matching electronic control system. The structure is compact and simple, reducing equipment manufacturing costs and operating failure rate, and is suitable for the continuous operation requirements of automotive fastener mass production lines.

[0018] 2. The dual-sided cam and friction wheel drive smoothly without rigid impact, enabling the fastener to achieve dual-degree-of-freedom posture adjustment, covering the blind area of ​​thread recesses, effectively improving the imaging clarity of the thread area, reducing the missed and false detection of micro-defects, and improving the accuracy of automotive fastener defect detection.

[0019] 3. The swing angle is adjustable and designed to match the thread parameters. Combined with a multi-dimensional protection and cleaning structure, it is suitable for testing various specifications of automotive fasteners, ensuring the consistency and reliability of test results and strong versatility. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention. Figure 1 ; Figure 2 This is a top view of the overall structure of an embodiment of the present invention; Figure 3 This is a front view of the overall structure of an embodiment of the present invention; Figure 4 This is a schematic diagram of the overall structure of an embodiment of the present invention. Figure 2 ; Figure 5 This is a schematic diagram of the installation of the transmission bracket according to an embodiment of the present invention. Figure 1 ; Figure 6 This is a schematic diagram of the installation of the transmission bracket according to an embodiment of the present invention. Figure 2 ; Figure 7 This is a schematic diagram of the installation of the transmission bracket according to an embodiment of the present invention. Figure 3 ; Figure 8 This is a partial cross-sectional view of the transmission bracket according to an embodiment of the present invention; Figure 9 for Figure 8 A magnified view of part A in the image; Figure 10 This is a schematic diagram of the installation of the self-rotating component according to an embodiment of the present invention; Figure 11 This is a schematic diagram of the support component installation according to an embodiment of the present invention; Figure 12 for Figure 11 A magnified view of part B in the image; Figure 13 This is a schematic diagram of the eccentric cam structure according to an embodiment of the present invention.

[0021] The components include: 1. Fastener transmission table; 11. Frame body; 12. First conveyor belt; 13. Second conveyor belt; 131. Receiving inclined plate; 2. Detection mechanism; 21. Imaging component; 22. Drive rack; 23. Ion nozzle; 3. Conveyor bracket; 31. Rotating shaft; 32. Support component; 33. Guide wheel; 331. Silicone sleeve; 332. Driven synchronous pulley; 34. First gear; 35. Eccentric cam; 351. Waist-shaped hole. 352. Tightening screw; 353. Adjusting threaded hole; 36. Second gear; 37. Driving friction wheel; 38. Driven friction wheel; 381. Driving synchronous pulley; 39. Synchronous belt; 391. Tensioner; 392. Waist-shaped adjusting hole; 310. Magnetic block; 311. Swing arm drive wheel; 312. Return spring; 313. Transmission belt; 314. Roller; 315. First bearing; 316. Second bearing; 4. Fasteners. Detailed Implementation

[0022] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0023] See Figures 1 to 13According to an embodiment of the defect detection equipment for automotive fastener production provided by the present invention, it includes a fastener transmission table 1, a detection mechanism 2, and a transfer bracket assembly. The fastener transmission table 1 includes a frame body 11, a first conveyor belt 12, and a second conveyor belt 13. The detection mechanism 2 is installed between the first conveyor belt 12 and the second conveyor belt 13. An imaging component 21 is provided inside the detection mechanism 2. A drive rack 22 is provided on the inner wall of the detection mechanism 2. The transfer bracket assembly includes a transfer bracket 3, which transfers fasteners 4 from the first conveyor belt 12 to the second conveyor belt 13. A support member 32 is connected inside the transfer bracket 3 via a rotating shaft 31. Several guide wheels 33 are installed on the support member 32, and the nut head of the fastener 4 is mounted above the guide wheels 33. A first gear 34 and an eccentric cam 35 are mounted on one side of the conveyor bracket 3, and the first gear 34 and the eccentric cam 35 are connected in a driving relationship. A second gear 36 and a driving friction wheel 37 are mounted on the other side of the conveyor bracket 3, and the second gear 36 and the driving friction wheel 37 are connected in a driving relationship. The first gear 34 and the second gear 36 are driven by the drive rack 22. A swing arm drive wheel 311 is fixed to the outer end of the rotating shaft 31, and the swing arm drive wheel 311 abuts against the outer circumferential surface of the eccentric cam 35. A return spring 312 is provided between the conveyor bracket 3 and the swing arm drive wheel 311 to keep the swing arm drive wheel 311 always in close contact with the surface of the eccentric cam 35. A driven friction wheel 38 is connected to the outer end of the support member 32, and the driven friction wheel 38 has a driving synchronous pulley 381. A driven synchronous pulley 332 is fixed to the guide wheel 33, and the driving synchronous pulley 381 and the driven synchronous pulley 332 are driven by a synchronous belt 39. The driven friction wheel 38 and the end face of the driving friction wheel 37 are axially pressed together.

[0024] Furthermore, the driven friction wheel 38 has a hollow structure and is mounted on the transmission bracket 3 via the first bearing 315. At the same time, a second bearing 316 is embedded inside, and the rotating shaft 31 of the support member 32 is installed inside the second bearing 316.

[0025] Specifically, the fastener transmission table 1 provides a supporting foundation for the continuous conveying of fasteners 4, enabling the loading and unloading of workpieces to be inspected, connecting preceding and following production processes, and meeting the continuous flow requirements in the mass production inspection of automotive fasteners 4. The frame body 11 provides stable mounting support for the conveyor belt and the inspection mechanism 2, ensuring the relative positional accuracy of each component and avoiding transmission alignment deviations caused by frame deformation. The first conveyor belt 12 is used to transport the automotive fasteners 4 to be inspected, orderly conveying the workpieces to the front end of the inspection station. The second conveyor belt 13 is used to receive the inspected fasteners 4 and transport them to the next process, realizing the automated continuous operation of the inspection process.

[0026] Furthermore, the first conveyor belt 12 has a hollow structure, which is used to suspend the fasteners 4 for conveying. Similarly, the second conveyor belt 13 also has a hollow structure.

[0027] Inspection unit 2 provides a closed, light-proof environment for optical inspection, preventing external ambient light from interfering with image quality. It also provides a mounting base for internal transmission and inspection components, solving the problems of uneven lighting and low image contrast in open inspection environments. Imaging component 21 integrates an industrial camera and optical lens, responsible for acquiring surface images of the threaded area of ​​fastener 4, providing an image data source for subsequent defect identification and realizing the function of visual defect detection. In this embodiment, imaging component 21 uses a 5-megapixel global shutter industrial camera, paired with dual telecentric lenses, at a frame rate of 30fps, capable of acquiring clear, motion-free images during workpiece movement, adapting to the inspection cycle of the automotive fastener 4 mass production line.

[0028] The first gear 34 and the second gear 36 serve as input components for the transmission on both sides, converting the kinetic energy of the linear movement of the transmission bracket 3 into rotational power. This eliminates the need for an additional drive motor, achieving purely mechanical passive transmission and reducing manufacturing costs and maintenance difficulty. In this embodiment, the gears are made of 45# steel with a heat treatment process, achieving a surface hardness of HRC28 to 32, balancing structural strength and wear resistance, and capable of withstanding long-term continuous meshing alternating loads. The eccentric cam 35, as the driving component for the oscillating motion, converts continuous drive rotation into intermittent contact rotation through its eccentric profile, achieving directional oscillating motion, thereby driving the fastener 4 to adjust its pitch angle and eliminating visual blind spots in the thread depth direction. The active friction wheel 37, as the power output component for the self-rotating motion, transmits torque through end-face friction contact, driving the driven side transmission structure to operate, achieving axial self-rotation of the fastener 4 and eliminating visual blind spots in the thread circumferential direction.

[0029] The conveyor bracket 3 moves synchronously with the conveying system and integrates a driven transmission structure that combines oscillation and rotation. This achieves synchronized linkage between conveying and inspection posture adjustment, solving the problem of low efficiency caused by the separate execution of workpiece transfer and inspection actions. The rotating shaft 31 provides rotational support for the support member 32, ensuring that the support member 32 drives the fastener 4 to rotate smoothly around the fixed axis. The support member 32 provides a mounting carrier for the guide wheel 33 and supports the fastener 4 workpiece, ensuring the stability of the workpiece's posture during rotation and oscillation.

[0030] Furthermore, there are two guide wheels 33, which are respectively arranged on the left and right sides of the support member 32. One guide wheel 33 is connected to the driven friction wheel 38 to achieve active rotation, and the other guide wheel 33 is a driven wheel, so that the fastener 4 placed above the two guide wheels 33 can rotate under the drive of the driven friction wheel 38.

[0031] The guide wheel 33 provides rolling support for the nut head of the fastener 4. Its own rotation drives the fastener 4 to rotate around its own axis, while simultaneously preventing hard friction from scratching the nut head surface, thus ensuring the workpiece's appearance quality. The drive rack 22 moves linearly synchronously with the conveyor bracket 3. When meshing with the corresponding gear, it converts the linear motion into gear rotation, providing power input for the swing and spin mechanisms on both sides. It is the core transmission component for achieving purely mechanical passive drive.

[0032] The swing arm drive wheel 311 engages with the contour of the eccentric cam 35, converting the eccentric rotational motion of the cam into its own oscillating motion. This oscillation is then transmitted synchronously to the support member 32 and the fastener 4 via the rotating shaft 31, serving as the transmission component for the oscillating power. The return spring 312 continuously provides elastic force, ensuring that the swing arm drive wheel 311 remains in close contact with the wheel surface of the eccentric cam 35, avoiding oscillation lag and impact caused by transmission backlash, and ensuring the continuous and smooth oscillation motion. The swing arm drive wheel 311 can slide relative to the rotating shaft 31 axially, but no relative rotation can be observed in the rotational direction. Preferably, a keyway is provided on the rotating shaft 31, and the swing arm drive wheel 311 is mounted on the rotating shaft 31 via a flat key.

[0033] In some embodiments, the contact surfaces of the eccentric cam 35 and the swing arm drive wheel 311 are inclined surfaces. The eccentric cam 35 is provided with an eccentrically arranged waist-shaped hole 351, which is driven to the first gear 34 by a tightening screw 352.

[0034] Specifically, the inclined contact engagement method can convert vertical rotation into horizontal rotation. The eccentrically arranged oblong hole 351 provides adjustment space for adjusting the eccentricity. Two tightening screws 352 are inserted into the adjusting threaded holes 353 on the side of the oblong hole 351. By changing the fixed position of the tightening screws 352 within the oblong hole 351, the actual eccentricity of the eccentric cam 35 is adjusted, thereby changing the swing angle and adapting to the inspection needs of automotive fasteners 4 with different thread parameters, improving the equipment's versatility. The tightening screws 352 serve as the transmission connector between the first gear 34 and the eccentric cam 35, transmitting the rotational power of the gear to the eccentric cam 35. They also serve as the installation reference for eccentricity adjustment, ensuring coaxiality of the transmission. The tightening screws 352 are countersunk, preventing them from protruding and affecting the friction drive of the outer surface.

[0035] In some embodiments, when the driving force requirement is low, the contact surfaces of the eccentric cam 35 and the swing arm drive wheel 311 are made of a material with high friction, and are driven by friction.

[0036] In some embodiments, when the driving force requirement is large, the swing arm drive wheel 311 is a helical gear structure, and the outer side of the eccentric cam 35 is provided with a toothed structure that matches the gear of the swing arm drive wheel 311. The meshing of the helical gear and the toothed structure can further improve the accuracy of the swing transmission and ensure the precise controllability of the swing angle. The toothed structure and the eccentric profile are integrated to avoid additional transmission errors.

[0037] In some embodiments, the conveyor support assembly further includes a transmission belt 313, the conveyor support 3 is mounted on the transmission belt 313, and the transmission belt 313 is mounted on the frame body 11 via a roller 314.

[0038] In some embodiments, the waist-shaped hole 351 is provided with an adjusting threaded hole 353 along its long axis, and the tightening screw 352 is fixedly connected in the waist-shaped hole 351 through the adjusting threaded hole 353.

[0039] The adjusting threaded holes 353 arranged along the long axis of the waist-shaped hole provide multiple locking points for fixing the tightening screw 352, which can realize the adjustment of the eccentricity and meet the swing angle requirements of fasteners 4 of different specifications. The threaded locking fixing method is reliable and can withstand the alternating load of continuous operation, avoiding the decrease in swing accuracy caused by the positional displacement of the tightening screw 352 under long-term operation, and ensuring the consistency of the equipment's long-term operation.

[0040] In some embodiments, the contact surfaces of the active friction wheel 37 and the driven friction wheel 38 are inclined and covered with a rubber wear-resistant layer.

[0041] The beveled contact mating method can convert vertical rotation into horizontal rotation. The rubber wear-resistant layer can increase the friction coefficient of the friction surface, ensure stable torque transmission, and buffer the impact vibration at the moment of engagement, preventing vibration from being transmitted to fastener 4 and causing image blurring. It can also reduce direct wear of the metal wheel body and extend the service life of the component.

[0042] In this embodiment, the rubber wear-resistant layer is made of nitrile rubber and is bonded to the end face of the metal wheel body through a vulcanization process. Controlled variable experiments verified that the rubber layer with a Shore hardness of 50 has insufficient coefficient of friction, resulting in a slippage rate of approximately 7% under high-speed transmission, making it unable to stably transmit torque. A rubber layer with a Shore hardness of 75 is too hard, resulting in poor cushioning and shock absorption, with a vibration amplitude reaching 0.12 mm at the moment of engagement, easily leading to image blurring. Nitrile rubber with a Shore hardness of 60 to 65 is preferred, reducing the slippage rate to below 0.3% and controlling the engagement vibration amplitude to within 0.03 mm, thus balancing transmission stability and cushioning and shock absorption, fully meeting the high-precision inspection requirements of automotive fasteners.

[0043] In some embodiments, a tensioning wheel 391 is rotatably mounted on the transmission bracket 3. The wheel body of the tensioning wheel 391 abuts against the timing belt 39. A waist-shaped adjustment hole 392 is provided at the position of the mounting seat of the tensioning wheel 391 on the transmission bracket 3.

[0044] Specifically, the tension pulley 391 provides continuous tension to the synchronous belt 39, offsetting the transmission backlash caused by belt slack after long-term operation, ensuring the accuracy of synchronous transmission, and avoiding problems such as slippage and speed fluctuations. The waist-shaped adjustment hole 392 provides adjustment space for the installation position of the tension pulley 391, allowing flexible adjustment of the tension to accommodate synchronous belts 39 of different lengths and specifications, while also facilitating equipment installation, commissioning, and subsequent maintenance. In this embodiment, the tension pulley 391 is made of engineering plastic, which is lightweight, has low rotational inertia, does not add extra transmission load, and causes minimal wear on the synchronous belt 39, extending its service life.

[0045] In some embodiments, the eccentricity e of the eccentric cam 35, the effective swing length L of the swing arm drive wheel 311 and the swing angle α satisfy the relationship: α=2・arcsin(e / L); and the swing angle α matches the thread parameters of the fastener 4 to be tested, satisfying α≥2・arctan(h / P), where h is the thread depth and P is the thread pitch.

[0046] This formula enables precise design of the eccentric cam 35 and the swing arm structure parameters, allowing the swing angle to completely cover the visual blind spot of the threaded recess, while avoiding ineffective swinging that reduces the detection cycle time. It fits the actual detection scenario of automotive fasteners 4 and improves the equipment's adaptability to fasteners 4 of different specifications.

[0047] Among them, the eccentricity e is the core parameter determining the swing amplitude. The larger the eccentricity, the larger the corresponding swing angle, and the deeper the thread depth that can be covered. However, an excessively large eccentricity will increase the transmission load and component wear. The effective swing length L of the swing arm drive wheel 311 refers to the lever arm length from the swing rotation center to the cam contact point. The lever arm length affects the ratio of eccentricity to swing angle, and also determines the magnitude of the transmission torque. The swing angle α is the total angle of pitch swing of the fastener 4, which is the core indicator for determining whether the thread blind zone is completely covered. Insufficient angle will cause the recessed area at the root of the thread to be unable to be captured by the imaging component 21, resulting in missed defect detection. The thread tooth depth h is the depth value of the thread tooth profile, reflecting the depth of the thread recess. The larger the tooth depth, the larger the swing angle required to fully expose the bottom of the recess. The thread pitch P is the axial distance between adjacent thread teeth. The smaller the pitch, the denser the thread teeth, the steeper the inclination angle of the recess, and the larger the swing angle required to cover the blind zone.

[0048] Specifically, the first formula, α = 2 arcsin(e / L), is derived based on the planar geometric swing relationship. When the eccentric cam 35 rotates, the eccentricity e is the linear stroke of the swing arm endpoint. The swing arm swings around the rotation center, and the stroke e corresponds to the swing arm length L and the sine of the half-swing angle. The total swing angle is twice the half-swing angle, hence this relationship is derived. The second formula, α ≥ 2 arctan(h / P), is derived based on the optical imaging geometry of the thread blind zone. The angle of the visual blind zone formed by the thread recess area is determined by the thread depth and pitch. The tangent of the blind zone on one side is approximately h / P. To ensure that both sides of the recess can be completely captured, the total swing angle must be greater than or equal to twice the angle of the blind zone on one side. Therefore, this matching condition is derived to ensure that the swing angle can completely cover the thread visual blind zone.

[0049] For the commonly used automotive fastener M8 bolt, the thread depth h is approximately 0.64mm and the pitch P is 1.25mm. Substituting into the second formula, the minimum swing angle α is calculated to be ≥2arctan(0.64 / 1.25)≈54.2 degrees. Setting the effective swing length L of the swing arm to 80mm, substituting into the first formula and taking the swing angle α as 60 degrees, the eccentricity e is calculated as e=Lsin(α / 2)=80*sin30°=40mm. The eccentric cam 35 and swing arm structure designed according to these parameters can cover the thread recess blind zone of the M8 bolt. In actual inspection, the blind zone coverage rate reaches 100%, and the micro-defect detection rate reaches 99.8%. If the swing angle is less than the calculated value, such as 45 degrees, the thread root blind zone cannot be completely covered, and the missed detection rate increases to 12%, verifying the necessity of this matching formula.

[0050] For M6 bolts, with a thread depth h of approximately 0.48 mm and a pitch P of 1 mm, the calculated minimum swing angle is ≥51.2 degrees. The eccentricity can be adjusted to 36 mm through the slotted hole 351, corresponding to a swing angle of approximately 53.1 degrees, which also meets the testing requirements, verifying the versatility of the adjustable structure.

[0051] In some embodiments, the surfaces of the two guide wheels 33 are provided with silicone sleeves 331.

[0052] The silicone sleeve 331 has a certain degree of elasticity and friction, which can increase the friction between the guide wheel 33 and the nut head of the fastener 4, ensuring stable transmission of spin power and preventing slippage. It can also buffer minor vibrations during transmission, reduce workpiece movement, and improve imaging stability. At the same time, the silicone material is soft and will not scratch the surface coating of the nut head of the fastener 4, ensuring the appearance quality of the automotive fastener 4 and avoiding secondary damage to the workpiece during the inspection process.

[0053] In this embodiment, the silicone sleeve 331 is made of vapor-phase silicone with a Shore hardness of 50 and a frosted surface. Comparative experiments verified that without the silicone sleeve 331, the slippage rate between the guide wheel 33 and the nut head was approximately 8%, and the workpiece surface scratch rate was approximately 3%. After adding the silicone sleeve 331, the slippage rate dropped to below 0.5%, the workpiece surface scratch rate dropped to 0, and the workpiece vibration amplitude decreased by 40%, while the imaging clarity was significantly improved, verifying the multiple beneficial effects of the silicone sleeve 331.

[0054] In some embodiments, a magnetic block 310 is provided on the lower side of the support member 32 of the conveyor bracket 3 for attracting the fastener 4 on the first conveyor belt 12 into the support member 32.

[0055] The magnetic block 310 can magnetically attract ferrous fasteners 4, maintaining the workpiece's position stability during transport and attitude adjustment. This prevents the workpiece from shifting or slipping during rotation and oscillation, improving the consistency of the inspection station's posture. The magnetic attraction method is convenient for picking up and placing parts, requiring no additional clamping mechanism. Combined with the lifting and feeding action of the conveyor bracket 3, it automatically completes the picking and placing of parts, resulting in a simple structure and reliable operation. In this embodiment, the magnetic block 310 uses neodymium iron boron strong magnetic material, providing stable attraction force and capable of attracting fasteners 4 weighing no more than 50g, completely covering the weight range of commonly used automotive fasteners 4.

[0056] In some embodiments, the magnetic block 310 is an electromagnetic structure. When the support member 32 moves to the vicinity of the first conveyor belt 12, it is automatically powered on to attract the fastener 4 to the support member 32. When the detection is completed and the fastener approaches the second conveyor belt 13, the magnetic block 310 is automatically powered off, so that the fastener 4 can be smoothly transferred to the second conveyor belt 13.

[0057] Furthermore, the second conveyor belt 13 is provided with a receiving ramp 131 at the receiving end position. The height of the receiving ramp 131 is flush with the upper end face of the support member 32. When the support member 32 moves the fastener 4 to the receiving ramp 131, the receiving ramp 131 can be inserted into the underside of the nut of the fastener 4 and then slide down onto the second conveyor belt 13 to disengage from the support member 32.

[0058] In some embodiments, at least one set of ion nozzles 23 are installed on the feed side wall of the detection mechanism 2. The air outlet direction of the ion nozzles 23 is towards the threaded area of ​​the fastener 4 entering the station. The air outlet angle of the ion nozzles 23 can be adjusted by the hinge seat.

[0059] The ion nozzle 23 can spray compressed air containing ions to remove metal debris, dust, and other impurities adhering to the thread surface of the fastener 4 before it enters the inspection station. Simultaneously, it eliminates static electricity on the workpiece surface, preventing impurities from forming false defects that interfere with the inspection results and reducing the false detection rate. The hinged base allows for flexible adjustment of the air outlet angle of the ion nozzle 23 to adapt to the cleaning needs of fasteners 4 of different specifications and lengths, ensuring effective cleaning of the entire thread area.

[0060] In the implementation process of this invention, during operation, the automotive fasteners 4 to be inspected are placed orderly on the first conveyor belt 12 and conveyed forward with the first conveyor belt 12. The conveyor bracket 3 moves synchronously with the conveying system. When it moves to the corresponding position on the first conveyor belt 12, the magnetic block 310 on the support member 32 attracts and lifts the fasteners 4, and the nut head of the fasteners 4 is mounted on the guide wheel 33. The conveyor bracket 3 continues to move forward and enters the detection mechanism 2. The drive racks 22 on both sides mesh with the first gear 34 and the second gear 36 respectively, converting the kinetic energy of linear movement into the rotational motion of the gears.

[0061] The first gear 34 on the left drives the eccentric cam 35 to rotate synchronously. The contour of the eccentric cam 35 drives the swing arm drive wheel 311. The swing arm drive wheel 311 drives the support member 32 and the fastener 4 to swing at a certain angle through the rotating shaft 31, eliminating the visual blind spot in the direction of thread depth. The second gear 36 on the right drives the active friction wheel 37 to rotate synchronously. The driven friction wheel 38 is pressed tightly against the end face of the active friction wheel 37. The friction force drives the driven friction wheel 38 to rotate, which drives the guide wheel 33 to rotate through the synchronous belt 39, thereby causing the fastener 4 to rotate around its own axis, eliminating the visual blind spot in the circumferential direction of the thread.

[0062] During the synchronous spinning and oscillation of fastener 4, imaging component 21 continuously acquires multiple frames of images of the threaded area and uses image recognition algorithms to determine whether surface defects exist. After the inspection is completed, conveyor bracket 3 continues to move forward, driving rack 22 to disengage from gear, stopping the oscillation and spinning motion. Conveyor bracket 3 then places fastener 4 onto the second conveyor belt 13 for transport to the next process, completing the inspection process for a single fastener 4.

[0063] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A defect detection device for automotive fastener production, comprising a fastener transmission table, a detection mechanism, and a conveyor support assembly, wherein the fastener transmission table includes a frame body, a first conveyor belt, and a second conveyor belt, characterized in that: The detection mechanism is installed between the first conveyor belt and the second conveyor belt. The detection mechanism is equipped with an imaging component and a drive rack is installed on the inner wall of the detection mechanism. The conveying support assembly is mounted on the frame body. The conveying support assembly includes a conveying support. A support member is connected inside the conveying support via a rotating shaft. Several guide wheels are mounted on the support member. The nut head of the fastener is mounted above the guide wheels. A first gear and an eccentric cam are mounted on one side of the conveying support. The first gear and the eccentric cam are connected in a driving connection. A second gear and an active friction wheel are mounted on the other side of the conveying support. The second gear and the active friction wheel are connected in a driving connection. The first gear and the second gear are connected in a driving connection with the drive rack. A swing arm drive wheel is fixed to the outer end of the rotating shaft, and the swing arm drive wheel abuts against the outer peripheral wheel surface of the eccentric cam; a return spring is provided between the transmission bracket and the swing arm drive wheel; The outer end of the support member is connected to a driven friction wheel, which is equipped with a driving synchronous pulley. The guide wheel is fixed with a driven synchronous pulley. The driving synchronous pulley and the driven synchronous pulley are driven by a synchronous belt. The driven friction wheel and the end face of the driving friction wheel are axially pressed together.

2. The defect detection equipment for automotive fastener production according to claim 1, characterized in that, The contact surfaces of the eccentric cam and the swing arm drive wheel are inclined surfaces. The eccentric cam is provided with an eccentrically arranged waist-shaped hole, which is connected to the first gear drive by a tightening screw.

3. The defect detection equipment for automotive fastener production according to claim 1, characterized in that, The conveyor support assembly also includes a transmission belt, the conveyor support is mounted on the transmission belt, and the transmission belt is mounted on the frame body via rollers.

4. A defect detection device for automotive fastener production according to claim 2, characterized in that, An adjusting threaded hole is provided along the long axis of the waist-shaped hole, and the tightening screw is fixedly connected inside the waist-shaped hole through the adjusting threaded hole.

5. A defect detection device for automotive fastener production according to claim 1, characterized in that, The contact surface between the active friction wheel and the driven friction wheel is an inclined surface and is covered with a rubber wear-resistant layer.

6. A defect detection device for automotive fastener production according to claim 1, characterized in that, The conveyor support is rotatably mounted with a tension wheel, the tension wheel body abuts against the timing belt, and the position of the tension wheel mounting base on the conveyor support is provided with a waist-shaped adjustment hole.

7. A defect detection device for automotive fastener production according to claim 1, characterized in that, The eccentricity e of the eccentric cam, the effective swing length L of the swing arm drive wheel and the swing angle α satisfy the following relationship: α=2・arcsin(e / L); and the swing angle α matches the thread parameters of the fastener to be tested, satisfying α≥2・arctan(h / P), where h is the thread depth and P is the thread pitch.

8. A defect detection device for automotive fastener production according to claim 1, characterized in that, The surfaces of the two guide wheels are fitted with silicone sleeves.

9. A defect detection device for automotive fastener production according to claim 1, characterized in that, The lower side of the support member of the conveyor bracket is provided with a magnetic block for attracting the fasteners on the first conveyor belt into the support member.

10. A defect detection device for automotive fastener production according to claim 1, characterized in that, The feeding side wall of the testing mechanism is equipped with at least one set of ion nozzles. The air outlet direction of the ion nozzles is towards the fastener thread area entering the work station, and the air outlet angle of the ion nozzles can be adjusted by the hinge seat.

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