Flange nut grabbing cap recognizing mechanism and cap recognizing method

Abstract

The invention provides a flange nut grabbing cap recognizing mechanism and a cap recognizing method, and relates to the technical field of assembly automation. Comprising a clamping assembly used for clamping an outer ring of a flange nut, a guiding assembly used for guiding a bit and an upward jacking driving piece used for driving the bit to jack upwards in the axial direction, and the clamping assembly comprises a gas finger and at least two clamping fingers connected to the gas finger; the clamping fingers are suitable for being symmetrically clamped on the outer ring of the flange nut in a point contact or arc contact mode, and the flange nut is prevented from rotating during cap recognition through the clamping force of the clamping fingers. The pressing plate assembly can descend to be pressed on the top of the flange nut when cap recognition of the flange nut is completed. An optical fiber sensor is arranged on the pressing plate and is suitable for detecting whether the clamping fingers grab the flange nut successfully or not. According to the scheme, the cap recognizing efficiency is improved, and the assembling efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of assembly automation equipment technology, and more specifically, to a flange nut gripping and recognition mechanism and method. Background Technology

[0002] In automated assembly processes, the tightening of flange nuts presents unique challenges, particularly when tightening from bottom to top. Existing technologies commonly employ vacuum-suction gripping mechanisms. These mechanisms utilize multiple suction holes on the suction head, employing negative pressure to adhere the flange nut's flat surface to the head, and relying on raised steps on the outer ring of the suction surface for center positioning. However, this structure has significant drawbacks: First, vacuum suction only provides axial fixing force and cannot create effective circumferential constraint, causing the nut to easily rotate within the suction head during the tightening process. Second, due to the lack of a reliable anti-rotation mechanism, the screwdriver requires a longer tightening time, reducing assembly efficiency and generating metal shavings due to repeated friction. These shavings gradually contaminate the vacuum suction channel, accelerating the wear of vacuum components and severely impacting equipment lifespan. Furthermore, existing technologies cannot provide effective axial vibration assistance during the thread engagement stage, leading to difficulties in initial thread engagement and further exacerbating slippage and shavings generation. Therefore, existing technologies urgently need improvement to address these issues. Summary of the Invention

[0003] The purpose of this application is to provide a flange nut gripping and identification mechanism to solve the above-mentioned technical problems.

[0004] The present invention employs the following solution: a flange nut gripping and cap-recognizing mechanism, comprising a gripping assembly for gripping the outer ring of the flange nut, a guiding assembly for guiding the bit, and an upward driving component for driving the bit upward along the axial direction. The gripping assembly includes pneumatic fingers and at least two clamping fingers connected to the pneumatic fingers. The clamping fingers are adapted to symmetrically grip the outer ring of the flange nut through point contact or arc contact, and the clamping force of the clamping fingers prevents the flange nut from rotating during cap recognition. A pressure plate assembly is provided between the two clamping fingers. The pressure plate assembly includes a lifting cylinder and a pressure plate connected to the lifting cylinder. The pressure plate is configured to descend and press against the top of the flange nut when cap recognition is completed, preventing the flange nut from jumping out of the bit. An optical fiber sensor is provided on the pressure plate, and the optical fiber sensor is adapted to detect whether the clamping fingers have successfully gripped the flange nut.

[0005] Furthermore, the guide assembly includes a mounting plate, on which an oil-free bushing is provided to guide the bit.

[0006] Furthermore, the upper drive component includes an upper electric cylinder, which is connected to a moving plate. The moving plate is connected to a screwdriver via a mounting block. The screwdriver is equipped with a spring telescopic assembly to give the bit an elastic stroke that extends and retracts axially. The screwdriver is connected to the bit via an adapter.

[0007] Furthermore, the upper electric cylinder is configured to drive the bit to rise to contact the nut and over-interference the thickness of at least one flange nut before cap recognition, and then drive the bit to rotate at a preset angle via a rotating device to recognize the cap.

[0008] Furthermore, an axial micro-vibration actuator is provided on the force transmission path of the upper drive component to superimpose axial micro-vibration onto the bit during the bit-opening stage.

[0009] Furthermore, the axial micro-vibration actuator is a voice coil linear actuator and / or a piezoelectric actuator.

[0010] Furthermore, the clamping fingers are provided with contact pads that contact the flange nut. The contact pads have anisotropic surface microstructures that are aligned with the torque direction of the flange nut, making the coefficient of friction in this direction higher than that in the opposite direction. This improves the anti-rotation capability during the threading and tightening process and reduces scratching during unloading.

[0011] Furthermore, the anisotropic surface microstructure of the contact pad is a micro-comb or sawtooth rib arranged along the torque direction, with a rib inclination angle of 20-30°, a pitch of 0.4-0.8 mm, and a rib height of 0.10-0.30 mm.

[0012] Furthermore, it also includes a control module electrically connected to the upper drive component. The control module is equipped with a tooth-opening trigger threshold and a jamming protection threshold, which are used to trigger and fault-tolerantly control the mechanical state of the cap recognition process.

[0013] The present invention also provides a flange nut recognition method based on the flange nut gripping and recognition mechanism, comprising: S1, the outer ring of the flange nut is clamped by the clamping assembly and the bit is guided and preloaded by the guide assembly; S2, when the detected torque reaches the bit-opening trigger threshold, the axial micro-vibration actuator is driven to superimpose axial micro-vibration on the bit within the range of 50 to 200 Hz and vertical stroke of 0.05 to 0.20 mm to reduce bit-opening friction; S3 utilizes a contact pad with an anisotropic microstructure to provide high friction in the torque direction to suppress slippage; S4: Once engagement is detected, the micro-vibration is terminated and tightening is completed; if the torque reaches the jamming protection threshold, the micro-vibration is stopped and the reverse test is performed.

[0014] Beneficial effects: A flange nut gripping and recognition mechanism and method are disclosed. The clamping assembly uses point contact or arc contact to symmetrically clamp the outer ring of the flange nut, combined with the pressing action of the pressure plate assembly. This effectively prevents the nut from rotating circumferentially and jumping out axially during the recognition process. It solves the problems of low efficiency and iron filings contamination caused by the inability of existing vacuum adsorption methods to provide circumferential constraints. It has the advantages of improving assembly efficiency, reducing metal filings contamination, and extending the service life of the equipment. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a flange nut gripping and recognition mechanism according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the clamping assembly of a flange nut gripping and cap recognizing mechanism according to an embodiment of the present invention; Figure 3 This is a front view schematic diagram of the clamping component of a flange nut gripping and cap recognizing mechanism according to an embodiment of the present invention; Figure label: 1. Air finger; 2. Clamping finger; 3. Flange nut; 4. Lifting cylinder; 5. Pressure plate; 6. Fiber optic sensor; 7. Mounting plate; 8. Oil-free bushing; 9. Top electric cylinder; 10. Moving plate; 11. Screwdriver; 12. Mounting block; 13. Adapter; 14. Screwdriver bit; 15. Contact pad; 16. Lifting mechanism. Detailed Implementation

[0016] Example 1 Combination Figures 1 to 3 As shown, this embodiment provides a flange nut gripping and cap-recognizing mechanism, including a gripping assembly for gripping the outer ring of a flange nut 3, a guiding assembly for guiding a bit 14, and an upward driving component for driving the bit 14 upward along the axial direction. The gripping assembly includes an air finger 1 and at least two gripping fingers 2 connected to the air finger 1. The gripping fingers 2 are adapted to symmetrically grip the outer ring of the flange nut 3 through point contact or arc contact, and the clamping force of the gripping fingers 2 prevents the flange nut 3 from rotating during cap recognition. A pressure plate assembly 5 is provided between the two gripping fingers 2. The pressure plate assembly 5 includes a lifting cylinder 4 and a pressure plate 5 connected to the lifting cylinder 4. The pressure plate 5 is configured to descend and press against the top of the flange nut 3 when cap recognition is completed, preventing the flange nut 3 from jumping out of the bit 14. A fiber optic sensor 6 is provided on the pressure plate 5, and the fiber optic sensor 6 is adapted to detect whether the gripping fingers 2 have successfully gripped the flange nut 3.

[0017] Combination Figures 1 to 3As shown, the clamping assembly is connected to a lifting mechanism 16, which drives the clamping finger assembly to rise and fall. The pneumatic finger 1 refers to a pneumatically driven clamping device, specifically a double-acting cylinder in conjunction with a linear guide rail, with the clamping finger 2 opening and closing controlled by pneumatic pressure. The clamping finger 2 refers to the gripper component that directly contacts the flange nut 3, and can be made of hard alloy or engineering plastic, with the clamping surface configured to form point or arc contact. The pressure plate assembly 5 refers to an execution unit with a downward pressing function; for example, a lifting cylinder 4 can drive the pressure plate 5, and an elastic buffer layer can be provided on the bottom surface of the pressure plate 5. The fiber optic sensor 6 can be a reflective fiber optic probe, which determines the gripping state by detecting changes in the gap between the clamping finger 2 and the nut. The guide assembly is a positioning mechanism that limits the radial offset of the bit 14, and can be an oil-free bushing 8 structure. The upper drive component refers to the power source that provides axial thrust, and can be an electric cylinder. When the pneumatic finger 1 drives the clamping finger 2 to close, the clamping points are symmetrically distributed on the outer circumference of the flange nut 3, forming a two-point contact or arc contact pattern. The point contact or curved contact design reduces the contact area, generating higher pressure under the same clamping force and enhancing anti-rotation capability. During the cap recognition process, the upper drive component pushes the bit 14 upward, and the guide component ensures that the axis of the bit 14 is aligned with the axis of the nut. When the screwdriver 11 begins to rotate, the friction torque provided by the clamping fingers 2 counteracts the torsional force generated during the threading stage. After the cap recognition is completed, the lifting cylinder 4 drives the pressure plate 5 to press down to the top plane of the nut, preventing the nut from jumping during subsequent tightening processes. The fiber optic sensor 6 monitors the position of the clamping fingers 2 in real time, triggering an alarm signal when it detects that the clamping fingers 2 are not fully closed.

[0018] This solution generates active constraint force through mechanical clamping. The point contact or arc contact design significantly increases pressure compared to surface contact, providing a greater anti-rotation torque under the same clamping force. The pressure plate assembly 5 intervenes after the cap is locked, avoiding interference with the tightening process and preventing axial movement of the nut. The guide assembly and the upper drive component work together to ensure precise alignment between the bit 14 and the nut, reducing the risk of thread misalignment and effectively suppressing circumferential sliding of the flange nut 3 during the cap locking stage, thus shortening the screwdriver 11's thread-opening time. The mechanical clamping method avoids metal-to-metal sliding friction, reducing chip generation. The phased action design of the pressure plate assembly 5 balances anti-rotation requirements with tightening freedom, ensuring the stability of the entire locking process.

[0019] In this embodiment, the guide assembly includes a mounting plate 7, on which an oil-free bushing 8 is provided to guide the bit 14. The mounting plate 7 is a rigid support structure for supporting the guide assembly and provides a mounting reference surface for the oil-free bushing 8. The oil-free bushing 8 is a lubrication-free sliding bearing element, which can be made of, for example, oil-impregnated sintered bronze or polymer composite material. Its inner hole forms a clearance fit with the outer diameter of the bit 14, and through its low coefficient of friction, it achieves linear guidance of the axial movement of the bit 14, solving the problem of nut rotation caused by bit 14 wobble, ensuring precise alignment of the bit 14 and the flange nut 3 threads, reducing metal debris generated by misalignment friction, and reducing the maintenance frequency of the guide structure.

[0020] Combination Figures 1 to 3 As shown, the upper drive component in this embodiment includes an upper electric cylinder 9, which is connected to a moving plate 10. The moving plate 10 is connected to a screwdriver 11 via a mounting block 12. The screwdriver 11 has a spring telescopic assembly inside, allowing the bit 14 to have an elastic stroke that extends and retracts axially. The screwdriver 11 is connected to the bit 14 via an adapter 13. The upper electric cylinder 9 can be implemented as a servo electric cylinder or a stepper electric cylinder, used to precisely control the axial displacement of the bit 14. The moving plate 10 is a load-bearing component rigidly connected to the output end of the electric cylinder, used to transmit driving force and maintain motion stability. The mounting block 12 is a connection structure used to fix the screwdriver 11, which can be a split locking block or a quick-change clamp for easy disassembly and maintenance. The spring telescopic assembly is a buffer mechanism with built-in elastic elements, used to provide elastic compensation when axial preload is applied. The adapter 13 is a transition component connecting the screwdriver 11 and the bit 14, for example, a hexagonal sleeve or a magnetic interface, to achieve quick replacement of the bit 14. During operation, the upper electric cylinder 9 drives the moving plate 10 to move the mounting block 12 and screwdriver 11 axially. The spring telescopic assembly causes the bit 14 to elastically deform upon contact with the flange nut 3 to buffer the impact load. When the bit 14 experiences axial resistance, the spring telescopic assembly compresses and stores energy, ensuring stable pressure between the bit 14 and the nut contact surface. The adapter 13 transmits the torque output from the screwdriver 11 to the bit 14. Through the coordinated control of the spring telescopic assembly and the electric cylinder, the bit 14 achieves dynamic compliant contact in the axial direction, avoiding thread damage caused by rigid impact. The modular design of the adapter 13 further improves the efficiency of bit 14 replacement, reduces maintenance costs, and solves the problem of thread misalignment and slippage caused by rigid axial contact during nut replacement.

[0021] In a preferred embodiment, the upper-lifting electric cylinder 9 is configured to first drive the bit 14 to contact the nut before capping, and then continue to lift it to interfere with the thickness of at least one flange nut 3. Afterwards, the bit 14 is driven to rotate by a preset angle via a rotating device to cap the nut. Interfering with the thickness of at least one flange nut 3 means that the distance the bit 14 continues to move upward after contacting the flange nut 3 is greater than the axial height of the flange nut 3. This can be achieved through closed-loop control using a displacement sensor or encoder to ensure preload is generated at the contact surface. The rotating device is the drive component that outputs rotational motion and can be implemented using a servo motor or a geared motor. It is used to apply rotational torque after axial preload to complete thread engagement. The preset angle is the initial rotation amount determined based on the thread profile of the flange nut 3. This can be controlled by feedback using an angle encoder or Hall sensor to ensure correct engagement at the beginning of the thread.

[0022] When the cap-recognition operation is initiated, the upper electric cylinder 9 first pushes the bit 14 axially, causing its end to contact the top of the flange nut 3 and continue to move upwards by a distance exceeding the thickness of the flange nut 3, forming an interference fit. At this time, the flange nut 3 is fixed by the clamping assembly, and the contact surface between the bit 14 and the nut generates preload pressure. Subsequently, the rotating device drives the bit 14 to rotate along the thread direction by a preset angle, causing the thread teeth of the bit 14 to initially engage with the internal thread of the flange nut 3, completing the cap-recognition action. This step-by-step operation mode avoids thread misalignment or stripping caused by synchronous action by establishing axial preload before applying rotational motion. By fixing the outer ring of the flange nut 3 with the clamping assembly and combining axial interference preload and step-by-step rotation control, a stable pressure is formed between the bit 14 and the nut at the contact surface, effectively suppressing relative slippage during rotation. At the same time, the step-by-step operation mode can precisely control the timing of axial and rotational actions, reducing the risk of thread misalignment. In a preferred embodiment, an axial micro-vibration actuator is also provided in the force transmission path of the upper drive member. The actuator superimposes axial micro-vibration onto the bit 14 during the bit-opening stage. Here, the axial micro-vibration actuator is integrated into the bit 14 assembly and is arranged in parallel with the upper drive member. The bit 14 assembly is provided with a hard limiting structure to limit the maximum axial displacement of the bit 14.

[0023] An axial micro-vibration actuator is a drive device capable of generating high-frequency, small-amplitude vibrations in the axial direction. It can be implemented using a voice coil linear actuator or a piezoelectric actuator, with its vibration frequency and stroke range adapted to the frictional characteristics of the thread-starting stage. A hard-limiting structure refers to a mechanical displacement constraint device, such as a rigid stop or limit pin, used to prevent the bit 14 from exceeding its safe axial displacement range due to vibration overload. When the bit 14 completes centering under the guidance of the guide assembly and the preload pressure reaches the set value, the control module sends a command to the axial micro-vibration actuator. The actuator generates high-frequency axial vibrations superimposed on the pushing action of the upper drive component, and the vibration energy is transmitted to the nut thread contact surface through the bit 14. Vibration parameters are dynamically adjusted according to the thread specification. During the thread-starting stage, high-frequency micro-vibration disrupts the static friction state, promoting initial thread engagement. By actively reducing frictional resistance through axial micro-vibration, combined with hard limiting to ensure the safety of the vibration process, the initial thread engagement time is shortened.

[0024] The voice coil linear actuator described here is a device that generates axial high-frequency reciprocating motion through electromagnetic drive. Specifically, it can be achieved by the interaction of a coil and a permanent magnet, offering fast response and high displacement resolution. The piezoelectric actuator, on the other hand, utilizes the inverse piezoelectric effect of piezoelectric materials to generate micro-displacement. This can be achieved using a laminated piezoelectric ceramic structure, exhibiting high-frequency response characteristics and nanometer-level displacement accuracy. Both actuators reduce static friction between the nut and the bit 14 through rapid axial vibration, thereby promoting smooth engagement during the thread-starting stage. The actuator's vibration parameters can be matched and adjusted according to different specifications of flange nuts 3. For example, the vibration frequency can be set to 50-200 Hz, and the amplitude can be controlled within the range of 0.05-0.20 mm. This actively regulates the friction state of the contact interface during the flange nut 3's cap-locking process, significantly improving the engagement efficiency during the thread-starting stage and reducing the risk of wear between the bit 14 and the nut. The high-frequency micro-amplitude vibration of the actuator effectively reduces frictional resistance without adversely affecting the nut's positioning accuracy, thus shortening the cap-locking time and reducing iron filings while ensuring anti-rotation performance.

[0025] Combination Figures 2 to 3As shown, in another preferred embodiment, the clamping finger 2 is provided with a contact pad 15 that contacts the flange nut 3. The contact pad 15 has an anisotropic surface microstructure aligned with the torque direction of the flange nut, making the coefficient of friction in this direction higher than that in the opposite direction. This improves anti-rotation capability during loosening and tightening and reduces scratching during unloading. Preferably, the ratio of the coefficient of friction of the contact pad 15 in the torque direction to that in the opposite direction is greater than or equal to 1.5. The contact pad 15 refers to an elastic material layer disposed on the contact surface between the clamping finger 2 and the flange nut 3. It can be made of polyurethane or silicone rubber composite, and its surface is microstructured to form directional friction characteristics. Anisotropic surface microstructures refer to regular geometric shapes arranged along a specific direction. For example, they can be achieved using micro-comb or serrated rib structures. The rib inclination angle, pitch, and height parameters are designed according to the friction coefficient requirements. For example, the rib inclination angle is set to 20–30°, the pitch to 0.4–0.8 mm, and the rib height to 0.10–0.30 mm. The rib inclination angle range is set to 20–30°, for example, 25°, to balance forward engagement strength and reverse disengagement smoothness. The pitch range can be, for example, 0.6 mm, to ensure rib structure density while avoiding excessive local stress. The rib height range can be, for example, 0.2 mm, to ensure effective embedding under clamping force without exceeding the elastic deformation limit of the contact pad 15.

[0026] The contact pad 15 forms dense mechanical interlocking points in the torque direction through its surface microstructure. When the nut is subjected to tightening torque, the contact pad 15 generates high frictional resistance along the torque direction, effectively suppressing slippage of the flange nut 3 during clamping. When unloading or reversing, the contact area between the inclined surface of the microstructure and the nut surface decreases, significantly reducing frictional resistance and thus minimizing scratch damage to the contact surface. This application achieves directional selectivity of the friction coefficient through anisotropic microstructures, reducing the risk of contact surface damage while ensuring anti-rotation performance.

[0027] This embodiment also includes a control module electrically connected to the upper drive component. The control module is equipped with a tooth-opening trigger threshold and a jamming protection threshold, used to trigger and fault-tolerantly control the mechanical state of the cap recognition process. The tooth-opening trigger threshold can be determined jointly based on the first derivative estimated from the motor current or torque and an axial displacement or velocity threshold. When the detected torque reaches the tooth-opening trigger threshold, the control module can maintain preload and trigger the upper drive component to maintain the upward movement within an 80 to 300 millisecond time window, and / or activate the axial micro-vibration actuator. When the torque is continuously not less than the jamming protection threshold and the root mean square value of the slip vibration exceeds the threshold for 120 milliseconds, the control module stops the upward movement and can control the bit 14 to reverse 2 to 3 teeth before attempting cap recognition again, with no more than 2 retries. Here, the sensing signal used by the control module to acquire the cap recognition state includes at least one axial force sensor, strain gauge, displacement encoder, or microelectromechanical system accelerometer; the sampling frequency is not less than 2 kHz.

[0028] Here, the thread-starting trigger threshold refers to the critical point at which the thread-starting stage of the nut is determined by real-time monitoring of the torque change rate and axial motion parameters. This can be achieved using a current sensor in conjunction with a displacement encoder to accurately identify the initial engagement state of the nut and the 14mm thread of the bit. The jamming protection threshold is a preset upper limit of torque, which can be achieved by measuring axial force changes using a strain gauge. This is used to trigger a protection mechanism when thread misalignment or foreign object jamming occurs. When the torque change rate exceeds the set threshold and the axial displacement reaches the preload stroke, the thread-starting stage is determined, and axial micro-vibration is triggered. During the preload process maintained within the preset time window, if the torque continuously exceeds the limit or the vibration energy is abnormal, the operation is immediately interrupted and a reverse reset action is performed. The sensor signals are redundantly verified using multi-source data fusion technology to ensure the reliability of the state determination.

[0029] In some specific embodiments, the axial force sensor can be integrated into the connection of the bit 14, the strain gauge can be attached to the surface of the guide component support structure, and the microelectromechanical system accelerometer can be embedded inside the pressure plate component 5. By collecting multi-dimensional sensing data in real time and establishing a dynamic threshold judgment mechanism, the precise control of the nut recognition process is realized, effectively avoiding repeated slippage caused by thread misalignment. Thus, the threading stage can be automatically detected and auxiliary actions can be triggered during the nut recognition process. When jamming occurs, a protective reset operation is performed in time, which significantly improves the assembly success rate. [2] Example 2 This application further proposes a method for identifying flange nuts, including the following steps: The outer ring of the flange nut 3 is clamped by the clamping assembly, and the bit 14 is guided and preloaded by the guide assembly. When the torque is detected to reach the starting trigger threshold, the axial micro-vibration actuator is driven to superimpose axial micro-vibration on the bit 14 in the range of 50-200 Hz frequency and vertical stroke of 0.05-0.20 mm to reduce starting friction. The contact pad 15 with anisotropic microstructure provides high friction in the torque direction to suppress slippage. When engagement is detected, the micro-vibration is terminated and tightening is completed. If the torque is detected to reach the jamming protection threshold, the micro-vibration is stopped and the reverse test is performed.

[0030] After the clamping assembly clamps the flange nut 3, the guide assembly performs axial preload positioning on the bit 14. When the bit 14 contacts the nut and reaches the preload force, the control module monitors the torque change rate and axial displacement signal in real time. Once the torque change rate exceeds the set threshold, the axial micro-vibration actuator immediately starts, using high-frequency, small-amplitude vibration to disrupt the static friction state of the thread contact surface. Simultaneously, the anisotropic contact pad 15 on the clamping fingers 2 inhibits the rotation and slippage of the flange nut 3 through directional friction characteristics. When the detected axial displacement mutation reaches the meshing characteristic value, the micro-vibration automatically stops and switches to the regular tightening process. If the torque continuously exceeds the limit or the vibration is abnormal during the thread-opening stage, the bit 14 performs a reverse action to release the jam, and triggers an alarm after two failed retries. This solves the problem of nut slippage and metal filings caused by insufficient anti-rotation capability of the vacuum adsorption mechanism, achieving stable thread opening through the synergistic effect of micro-vibration and anisotropic friction. The dynamic monitoring and reverse protection mechanism effectively avoids equipment damage caused by thread jamming, improving the reliability and efficiency of flange nut 3 assembly. The directional friction design of the contact pad 15 further enhances the anti-rotation capability, ensuring stable clamping during both tightening and unloading.

[0031] It should be understood that the above are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions that fall within the scope of the present invention are within the scope of protection of the present invention.

[0032] The accompanying drawings used in the above description of the embodiments only illustrate certain embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

Claims

1. A flange nut gripping and identification mechanism, characterized in that, It includes a clamping assembly for holding the outer ring of the flange nut, a guide assembly for guiding the bit, and an upper pusher for driving the bit upward axially. The clamping assembly includes an air finger and at least two clamping fingers connected to the air finger. The clamping fingers are adapted to symmetrically clamp the outer ring of the flange nut by point contact or arc contact, and the clamping force of the clamping fingers prevents the flange nut from rotating when the cap is engaged. A pressure plate assembly is provided between the two gripping fingers. The pressure plate assembly includes a lifting cylinder and a pressure plate connected to the lifting cylinder. The pressure plate is configured to descend and press against the top of the flange nut when the flange nut is fully engaged, preventing the flange nut from jumping out of the bit. An optical fiber sensor is provided on the pressure plate, which is adapted to detect whether the gripping fingers have successfully engaged the flange nut.

2. The flange nut gripping and identification mechanism according to claim 1, characterized in that, The guide assembly includes a mounting plate, on which an oil-free bushing is provided to guide the bit.

3. The flange nut gripping and identification mechanism according to claim 1, characterized in that, The upper drive component includes an upper electric cylinder, which is connected to a moving plate. The moving plate is connected to a screwdriver via a mounting block. The screwdriver contains a spring telescopic assembly to give the bit an elastic stroke that extends and retracts axially. The screwdriver is connected to the bit via an adapter.

4. The flange nut gripping and identification mechanism according to claim 3, characterized in that, The upper electric cylinder is configured to drive the bit to rise to contact the nut and over-interference the thickness of at least one flange nut before cap recognition, and then drive the bit to rotate at a preset angle through a rotating device to recognize the cap.

5. The flange nut gripping and identification mechanism according to claim 1, characterized in that, An axial micro-vibration actuator is provided on the force transmission path of the upper drive component to superimpose axial micro-vibration onto the bit during the bit-opening stage.

6. The flange nut gripping and identification mechanism according to claim 5, characterized in that, The axial micro-vibration actuator is a voice coil linear actuator and / or a piezoelectric actuator.

7. The flange nut gripping and identification mechanism according to claim 1, characterized in that, The clamping fingers are provided with contact pads that contact the flange nut. The contact pads have anisotropic surface microstructures that are aligned with the torque direction of the nut, making the coefficient of friction in this direction higher than that in the opposite direction. This improves the anti-rotation capability during the opening and tightening process and reduces the scraping resistance during unloading.

8. The flange nut gripping and identification mechanism according to claim 7, characterized in that, The anisotropic surface microstructure of the contact pad consists of micro-comb or sawtooth ribs arranged along the torque direction, with a rib inclination angle of 20–30°, a pitch of 0.4–0.8 mm, and a rib height of 0.10–0.30 mm.

9. The flange nut gripping and identification mechanism according to claim 1, characterized in that, It also includes a control module electrically connected to the upper drive component. The control module is equipped with a tooth-starting trigger threshold and a jamming protection threshold, which are used to trigger and fault-tolerantly control the mechanical state of the cap recognition process.

10. A flange nut recognition method based on the flange nut gripping and recognition mechanism according to any one of claims 1 to 9, characterized in that... include: S1, the outer ring of the flange nut is clamped by the clamping assembly and the bit is guided and preloaded by the guide assembly; S2, when the detected torque reaches the bit-opening trigger threshold, the axial micro-vibration actuator is driven to apply axial micro-vibration to the bit in the range of 50 to 200 Hz and vertical stroke of 0.05 to 0.20 mm to reduce bit-opening friction; S3 utilizes a contact pad with an anisotropic microstructure to provide high friction in the torque direction to suppress slippage; S4: Once engagement is detected, the micro-vibration is terminated and tightening is completed; if the torque reaches the jamming protection threshold, the micro-vibration is stopped and the reverse test is performed.

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