Fastening system, pre-tightening force control method and storage medium

Abstract

The invention discloses a fastening system, a pre-tightening force control method and a storage medium, the fastening system comprises a fastening sleeve, a fastening tool and an integrated module, the fastening sleeve comprises an ultrasonic probe, the fastening tool comprises a tool controller, and the ultrasonic probe and the tool controller are both electrically connected with the integrated module; the fastening sleeve is matched with a fastening tool and is used for being matched with a threaded fastener, the fastening sleeve further comprises a first elastic piece, and the first elastic piece is used for enabling the ultrasonic probe to abut against the threaded fastener; the integrated module is used for controlling the ultrasonic probe to transmit ultrasonic waves and receiving and processing ultrasonic echo signals, and is also used for determining echo time, determining pre-tightening force according to the echo time and sending the pre-tightening force to the tool controller, and the tool controller is used for controlling the fastening tool to keep running or stop running according to the pre-tightening force. In the embodiment of the invention, the pre-tightening force after the threaded fastener is tightened can be accurately controlled.

Description

Technical Field

[0001] This application relates to the technical field of preload control methods, and in particular to a fastening system, a preload control method, and a storage medium. Background Technology

[0002] Threaded fasteners, such as bolts, are widely used connecting elements in mechanical connections. When a threaded fastener is tightened, a preload is generated in its axial direction, which affects the quality of the connection.

[0003] In related technologies, threaded fasteners are usually tightened manually using tools, and the preload is measured by a sensor after the threaded fasteners are tightened.

[0004] However, due to the operator's experience, the preload of threaded fasteners fluctuates greatly after tightening, making it impossible to accurately control the preload after tightening. Summary of the Invention

[0005] This application provides a fastening system, a preload control method, and a storage medium, aiming to at least solve the technical problem in the prior art that the preload of threaded fasteners cannot be accurately controlled after tightening.

[0006] In a first aspect, embodiments of this application provide a fastening system, including a fastening sleeve, a fastening tool, and an integrated module. The fastening sleeve includes an ultrasonic probe, and the fastening tool includes a tool controller. Both the ultrasonic probe and the tool controller are electrically connected to the integrated module. The fastening sleeve cooperates with the fastening tool and is used to cooperate with the threaded fastener. The fastening sleeve also includes a first elastic element, which is used to cause the ultrasonic probe to abut against the threaded fastener. The integrated module is used to control the ultrasonic probe to emit ultrasonic waves and receive and process ultrasonic echo signals. It is also used to determine the echo time, determine the preload of the threaded fastener based on the echo time, and send the preload to the tool controller. The tool controller is used to control the fastening tool to keep running or stop running based on the preload.

[0007] Optionally, the fastening sleeve further includes a sleeve body and an angle compensation structure; The angle compensation structure includes a first piece having a concave spherical surface and a second piece having a convex spherical surface that mates with the concave spherical surface. The second piece can swing relative to the first piece about the center of the convex spherical surface. The first piece is movably connected to the sleeve body along the axial direction of the sleeve body. The second piece is fixedly connected to the outer periphery of the ultrasonic probe. When the fastening sleeve engages with the threaded fastener, the first elastic element applies an elastic force toward the threaded fastener to the first element.

[0008] Optionally, the integrated module includes a first control module, a transmitting circuit module, and a second control module. The transmitting circuit module is electrically connected to the first control module, and the first control module is communicatively connected to the second control module. The first control module is used to send a trigger signal to the transmitting circuit module so that the transmitting circuit module outputs an excitation signal to the ultrasonic probe to control the ultrasonic probe to emit ultrasonic waves; the second control module is used to determine the echo time, determine the preload of the threaded fastener based on the echo time, and send the preload to the tool controller.

[0009] Optionally, the integrated module further includes a digital communication isolation circuit, through which the first control module and the second control module are communicatively connected.

[0010] Optionally, the digital communication isolation circuit includes a first dual-channel digital isolator, which is electrically connected to the first transmitting end and the first receiving end of the first control module, and electrically connected to the second transmitting end and the second receiving end of the second control module.

[0011] Optionally, the integrated module further includes a receiving circuit module and an analog-to-digital converter module electrically connected to the receiving circuit module; The receiving circuit module is used to receive the ultrasonic echo signal output by the ultrasonic probe, process the ultrasonic echo signal and output a second signal to the analog-to-digital conversion module, and the analog-to-digital conversion module is used to perform analog-to-digital conversion processing on the second signal and output a third signal to the second control module. The first control module is used to send the trigger signal to the transmitting circuit module and simultaneously send a first signal to the second control module; the second control module is used to receive the first signal and determine a first time when the first signal is received; receive the third signal and determine a second time when the third signal is received; determine the echo time based on the first time, the second time, and a preset transmission time; determine the preload based on the echo time, and send the preload to the tool controller.

[0012] Optionally, the receiving circuit module includes at least one operational amplifier, and the transmitting circuit module includes a boost converter chip.

[0013] Optionally, the integrated module further includes a power module, which includes a power input terminal, a voltage conversion circuit, and an isolation power circuit. The voltage conversion circuit is electrically connected to the power input terminal and to the first control module. The isolation power supply circuit is electrically connected to the power input terminal and to the second control module.

[0014] Secondly, embodiments of this application provide a preload control method applied to the fastening system described above, the preload control method comprising: Receive a first signal and determine the first time the first signal is received; wherein the first signal is sent simultaneously by the first control module in the integrated module sending a trigger signal, and the trigger signal is used to cause the transmitting circuit module to output an excitation signal to the ultrasonic probe; Receive a third signal and determine a second time when the third signal is received; wherein the third signal is obtained by processing the ultrasonic echo signal output by the ultrasonic probe; The echo time is determined based on the first time, the second time, and the preset transmission time, and the preload of the threaded fastener is determined based on the echo time. The preload is output to the tool controller so that the tool controller controls the fastening tool to keep running or stop running based on the preload. Thirdly, embodiments of this application provide a readable storage medium storing a computer program, which, when executed by a processor, implements the preload control method as described above.

[0015] In this embodiment, during the tightening of threaded fasteners using a fastening tool and a fastening sleeve, an ultrasonic probe in the fastening sleeve emits ultrasonic waves and captures the returning ultrasonic waves. The integrated module determines the real-time preload of the threaded fastener based on the echo time. The tool controller controls the fastening tool to continue operating or stop operating based on the preload, thus enabling the fastening tool to stop operating when the preload reaches the target preload. This allows for precise control of the preload after tightening the threaded fastener, making the fastening system applicable to scenarios requiring high precision in the preload of tightened threaded fasteners. During the tightening process, it is necessary to maintain effective contact between the ultrasonic probe and the threaded fastener to ensure the measurement accuracy of the preload. In this embodiment, a first elastic element allows the ultrasonic probe to abut against the threaded fastener, ensuring effective contact and guaranteeing the measurement accuracy of the preload. Furthermore, compared to integrating the probe onto the threaded fastener, this fastening sleeve with an integrated ultrasonic probe is reusable, resulting in lower operating costs. In addition, measuring the preload during the tightening process of threaded fasteners can improve work efficiency compared to measuring the preload after the threaded fasteners are tightened.

[0016] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application, it can be implemented according to the contents of the specification. In order to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0017] Figure 1 A structural block diagram of a fastening system provided in an embodiment of this application; Figure 2 A structural block diagram of another fastening system provided in the embodiments of this application; Figure 3 Pin identification diagram of the first control module in the fastening system provided in the embodiments of this application; Figure 4 A schematic diagram of the transmitting circuit module and ultrasonic probe in the fastening system provided in the embodiments of this application; Figure 5 A schematic diagram of a digital communication isolation circuit in a fastening system provided in an embodiment of this application; Figure 6 A schematic diagram of the receiving circuit module in the fastening system provided in the embodiments of this application; Figure 7 A schematic diagram of the first-stage step-down circuit in the fastening system provided in the embodiments of this application; Figure 8 A schematic diagram of the second-stage step-down circuit in the fastening system provided in the embodiments of this application; Figure 9 A schematic diagram of the first-stage isolation circuit in the fastening system provided in the embodiments of this application; Figure 10 A schematic diagram of the second-stage isolation circuit in the fastening system provided in the embodiments of this application; Figure 11 A schematic diagram of the overall structure of the fastening sleeve in the fastening system provided in the embodiments of this application; Figure 12 This is a schematic cross-sectional view of the fastening sleeve in the fastening system provided in the embodiments of this application; Figure 13 This is a partial cross-sectional schematic diagram of the fastening sleeve in the fastening system provided in the embodiments of this application; Figure 14 A partial structural diagram of the fastening sleeve in the fastening system provided in the embodiments of this application. Figure 1 ; Figure 15 A partial structural diagram of the fastening sleeve in the fastening system provided in the embodiments of this application. Figure 2 ; Figure 16 A partial structural diagram of the fastening sleeve in the fastening system provided in the embodiments of this application. Figure 3 ; Figure 17 Schematic diagram of the structure of the first sleeve in the fastening system provided in the embodiments of this application Figure 1 ; Figure 18 Schematic diagram of the structure of the first sleeve in the fastening system provided in the embodiments of this application Figure 2 ; Figure 19 Schematic diagram of the structure of the second sleeve in the fastening system provided in the embodiments of this application Figure 1 ; Figure 20 Schematic diagram of the structure of the second sleeve in the fastening system provided in the embodiments of this application Figure 2 ; Figure 21 Schematic diagram of the structure of the third sleeve in the fastening system provided in the embodiments of this application Figure 1 ; Figure 22 Schematic diagram of the structure of the third sleeve in the fastening system provided in the embodiments of this application Figure 2 .

[0018] Figure label: 1-Sleeve body, 11-First sleeve component, 111-First mating part, 1111-Quick-connect groove, 112-Connecting groove, 1121-Arc-shaped groove wall, 1122-Flat groove wall, 113-First threaded hole, 114-Second threaded hole, 12-Second sleeve component, 121-Second mounting hole, 122-Connecting part, 1221-Arc-shaped outer wall, 1222-Flat outer wall, 123-Connecting hole, 124-First threaded hole 125-First groove, 126-First connecting hole, 127-Second through hole, 128-First stepped surface, 13-Third sleeve, 131-Second mating part, 1311-Matching groove, 132-First mounting hole, 133-Boss, 134-Second protrusion, 135-Second groove, 136-Third threaded hole, 137-Second stepped surface, 14-First clamping member, 15-Second clamping member; 2-Probe assembly, 21-Ultrasonic probe, 211-Detection surface, 22-Probe wire, 3-Elastic component, 31-First elastic element, 32-Second elastic element, 4-Fisheye bearing, 41-Outer ring, 42-Inner ring, 5-Outer shell, 51-Outer shell sub-component, 511-First through hole, 512-Third through hole, 6-Electric slip ring, 61-Slip ring rotor, 62-Slip ring stator, 7-Fixed lead wire, 8-Sealing sleeve, 9-Hole plug, 10-Bearing. Detailed Implementation

[0019] Exemplary embodiments of the present application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of the present application to those skilled in the art.

[0020] In related technologies, threaded fasteners are typically tightened manually using tools, and the preload is measured by a sensor after tightening. However, due to the operator's experience, the preload of the tightened threaded fastener fluctuates greatly, making it impossible to accurately control the preload. To address these issues, this application provides a fastening system, a preload control method, and a storage medium. The fastening system, preload control method, and storage medium are described in detail below.

[0021] Firstly, referring to Figure 1 , Figures 11 to 13 This application discloses a fastening system, including a fastening sleeve, a fastening tool, and an integrated module. The fastening sleeve includes an ultrasonic probe 21, and the fastening tool includes a tool controller. Both the ultrasonic probe 21 and the tool controller are electrically connected to the integrated module. The fastening sleeve cooperates with the fastening tool and is used to cooperate with threaded fasteners. The fastening sleeve also includes a first elastic element 31, which is used to make the ultrasonic probe 21 abut against the threaded fastener. The integrated module is used to control the ultrasonic probe 21 to emit ultrasonic waves and receive and process ultrasonic echo signals. It is also used to determine the echo time, determine the preload based on the echo time, and send the preload to the tool controller. The tool controller is used to control the fastening tool to keep running or stop running based on the preload.

[0022] The fastening tool is an electric fastening tool, such as an electric tightening gun. The tool controller can be a controller including a DSP (Digital Signal Processor) or a SOC (System on Chip) controller. The fastening tool also includes a motor and an output shaft. The tool controller is electrically connected to the motor to control its operation; the motor drives the output shaft to rotate. The ultrasonic probe 21 is connected to the integrated module via a wired electrical connection, and the tool controller is connected to the integrated module via either a wired electrical connection or a wireless connection. The integrated module can include one control module or two control modules. The fastening sleeve includes a sleeve body. During the tightening of threaded fasteners using a fastening tool and the fastening sleeve, the sleeve body 1 rotates with the rotation of the output shaft, and the threaded fastener rotates with the rotation of the sleeve body 1. The sleeve body 1 has a first mating portion 111, which mates with the fastening tool. Specifically, the first mating portion 111 engages with the fastening tool, for example, with the output shaft of an electric tightening gun. As an example, the first mating portion 111 has a quick-connect groove 1111 for engaging with the output shaft of the electric tightening gun. As another example, the first mating portion 111 is a first insertion protrusion for engaging with a groove on the output shaft of the electric tightening gun.

[0023] The first elastic element 31 is a component capable of providing elastic force, such as a helical spring or a wave spring. The ultrasonic probe 21 has a detection surface 211. When the fastening sleeve mates with the head of the threaded fastener, specifically, the detection surface 211 of the ultrasonic probe 21 abuts against the head end face of the threaded fastener. The head end face of the threaded fastener is also the end face of the threaded fastener that faces away from the rod portion.

[0024] The echo time is the time it takes for the ultrasonic wave emitted by the ultrasonic probe 21 to propagate axially through the threaded fastener to the distal end and return; that is, the time difference between the time the ultrasonic probe 21 emits the ultrasonic wave and the time it captures the returning ultrasonic wave. The ultrasonic probe 21 can emit and capture the returning ultrasonic wave. Based on the acoustoelastic effect, when the preload stress of the threaded fastener changes, the propagation speed of the ultrasonic wave will change accordingly. Therefore, there is a corresponding relationship between the acoustic time of ultrasonic wave propagation, i.e., the echo time, and the preload stress of the threaded fastener. Based on this relationship, the preload stress of the threaded fastener can be calculated by measuring the echo time, and the preload force of the threaded fastener can be determined according to the preload stress value and the cross-sectional area of ​​the threaded fastener.

[0025] Determining the preload of a threaded fastener based on the echo time includes: calculating the preload stress of the threaded fastener based on the echo time, and determining the preload based on the preload stress and the cross-sectional area of ​​the threaded fastener. The preload of the threaded fastener is the preload stress multiplied by the cross-sectional area of ​​the threaded fastener. The calculated preload can retain a preset number of decimal places, which can be one, two, etc.

[0026] Controlling the operation of the fastening tool based on preload includes: if the preload is greater than or equal to a preset target preload, the fastening tool stops operating; if the preload is less than the preset target preload, the fastening tool continues operating. Stopping the fastening tool also means stopping the motor within the fastening tool, thus preventing the output shaft from rotating. Maintaining operation of the fastening tool means keeping the motor within the fastening tool running, thus keeping the output shaft rotating.

[0027] In this embodiment, during the tightening of threaded fasteners using a fastening tool and a fastening sleeve, the ultrasonic probe 21 in the fastening sleeve emits ultrasonic waves and captures the returning ultrasonic waves. The integrated module determines the real-time preload of the threaded fastener based on the echo time. The tool controller controls the fastening tool to continue operating or stop operating based on the preload, thereby enabling the fastening tool to stop operating when the preload reaches the target preload. This allows for precise control of the preload after tightening the threaded fastener, making the fastening system applicable to scenarios requiring high precision in the preload of tightened threaded fasteners. During the tightening process, it is necessary to maintain effective contact between the ultrasonic probe 21 and the threaded fastener to ensure the measurement accuracy of the preload. In this embodiment, the first elastic element 31 allows the ultrasonic probe 21 to abut against the threaded fastener, thus maintaining effective contact and ensuring the measurement accuracy of the preload. Furthermore, compared to integrating the probe onto the threaded fastener, the fastening sleeve with the integrated ultrasonic probe 21 is reusable, resulting in lower operating costs. In addition, measuring the preload during the tightening process of threaded fasteners can improve work efficiency compared to measuring the preload after the threaded fasteners are tightened.

[0028] As an example, the formula for calculating the preload stress of threaded fasteners can be:

[0029] in, This refers to the preload stress of threaded fasteners. When the threaded fastener is in a pre-tightened state, the time difference between the ultrasonic wave emitted by the ultrasonic probe 21 and the time between the captured echo wave is the aforementioned echo time. The time difference between the ultrasonic wave emitted by the ultrasonic probe 21 and the return ultrasonic wave when the threaded fastener is not in a pre-tightened state, that is, when the pre-tightening force is zero. K The stress coefficient is obtained through calibration experiments and is related to the material properties and geometry of the threaded fastener. It should be noted that the time difference between the ultrasonic probe 21 emitting the ultrasonic wave and capturing the returning ultrasonic wave when the threaded fastener is not in a pre-tightened state is still measured using the aforementioned fastening sleeve and integrated module. This ensures that the measurement conditions for the time difference remain consistent between when the threaded fastener is not in a pre-tightened state and when it is in a pre-tightened state, thereby guaranteeing the accuracy of the pre-tightening force measurement.

[0030] The derivation process of the formula for calculating the preload stress of the above-mentioned threaded fasteners can be as follows: Ignoring the change in medium density caused by stress state variations, establish the longitudinal wave propagation velocity of ultrasound under stress-free conditions. And the propagation velocity of ultrasonic longitudinal waves under stress The process of establishing a relational expression is as follows: Bolts are typically made of metal, which is an isotropic solid medium. For an isotropic solid medium, a vector field can be expressed as the sum of a scalar gradient and a vector curl, therefore: (1) (2) In equations (1) and (2), Represents the velocity vector. Represents scalar potential. Represents vector potential, and These are operators used in vector analysis. It is the gradient operator. It is the curl operator. In other words, divergence is a fundamental operator used in vector analysis. Separating the scalar potential and vector potential, we get: (3) (4) In equations (3) and (4), This indicates the density of threaded fasteners. and These are all second-order elastic coefficients of threaded fasteners. t It is a time variable. It is a vector differential operator. Generally speaking, scalar and vector potentials describe longitudinal and transverse waves, respectively. Therefore, under stress-free conditions, the propagation velocities of ultrasonic longitudinal and transverse waves in a metallic medium can be expressed as: (5) (6) In equations (5) and (6), and These represent the propagation speeds of ultrasonic longitudinal waves and ultrasonic transverse waves under stress-free conditions, respectively.

[0031] Depending on the direction of ultrasonic wave propagation, the acoustic elasticity equations for different propagation directions can be expressed as follows: [2l] + (4) m +4 +10 (7) [2l-] (m + +2 (8) (4) + m + (9) ( m -2 - (10) In equations (7)-(10), This indicates the preload stress of the threaded fastener. This represents the density of the bolt under stress. l、m and n These represent the third-order elastic coefficients of the threaded fastener. This represents the longitudinal wave propagation speed of ultrasound parallel to the direction of stress. This represents the longitudinal wave propagation speed of ultrasound perpendicular to the direction of stress. This represents the propagation speed of ultrasonic longitudinal and transverse waves parallel to the direction of stress. This represents the propagation speed of ultrasonic transverse waves perpendicular to the direction of stress.

[0032] Because ultrasonic transverse waves are shear waves, their polarization direction is always perpendicular to the stress direction, but their propagation direction is not uniform. Since ultrasonic longitudinal waves, parallel to the stress direction, are most sensitive to stress changes, and ultrasonic longitudinal wave transducers are more commonly used and less expensive, they are typically... Equivalent to the propagation velocity of ultrasonic longitudinal waves under stress, and based on the transit time method, ultrasonic longitudinal waves are used to detect the preload stress of bolts. Therefore, combining equations (5) and (7), the change in medium density caused by the change in stress state is ignored, that is... Then we can get: (11) make: (12) In equations (11) and (12), The longitudinal wave propagation velocity of ultrasound under stress. Let be the acoustoelastic coefficient of the material. From equation (12), it can be seen that the acoustoelastic coefficient is only related to the second and third elastic coefficients of the material and is not affected by other factors. Therefore, substituting equation (12) into equation (11) yields: (13) Equation (13) is the longitudinal wave propagation velocity of ultrasound under stress-free conditions. And the propagation velocity of ultrasonic longitudinal waves under stress The relational expression.

[0033] Establish the ultrasonic transit time under stress, which is also known as the echo time. The ultrasonic transit time under stress-free conditions, i.e., the time difference between the ultrasonic wave emitted by the ultrasonic probe 21 and the time when the threaded fastener is not in a pre-tightened state, is the time difference between the time when the ultrasonic probe 21 emits the ultrasonic wave and the time when the returned ultrasonic wave is captured. The process of establishing a relational expression is as follows: Establish the relationship between the elongation of threaded fasteners under preload stress: (14) In equation (14), It is the total length of the threaded fastener when it is not under stress. It is the total length of the threaded fastener under stress. E It is the elastic modulus of threaded fasteners.

[0034] Combining equations (13) and (14) and Represented as: (15) (16) For metallic materials, the acoustoelastic coefficient The order of magnitude is extremely small, typically within the safe stress range of threaded fasteners. Therefore, equation (15) can be approximately simplified to: (17) Equation (17) is the establishment and The relational expression.

[0035] The tightening stress of the threaded fastener in equation (17) The extracted values ​​yielded: (18) in, K Stress coefficient, .

[0036] According to equation (18):

[0037] In some embodiments, refer to Figure 2The integrated module includes a first control module, a transmitting circuit module, and a second control module. The transmitting circuit module is electrically connected to the first control module, and the first control module is communicatively connected to the second control module. The first control module is used to send a trigger signal to the transmitting circuit module so that the transmitting circuit module outputs an excitation signal to the ultrasonic probe 21 to control the ultrasonic probe 21 to emit ultrasonic waves. The second control module is used to determine the echo time, determine the preload of the threaded fastener based on the echo time, and send the preload to the tool controller.

[0038] The first control module can be a microcontroller unit (MCU), and the second control module can be a field-programmable gate array (FPGA) module, which includes an FPGA chip. The microcontroller is preferably a 32-bit microcontroller, such as an STM32F103C8T6. The trigger signal can be either a high-level or low-level signal. The excitation signal is a high-voltage signal, for example, a 95V voltage signal. After receiving the trigger signal, the transmitting circuit module outputs the excitation signal to the ultrasonic probe 21. The first control module also outputs a non-trigger signal to the transmitting circuit module so that the transmitting circuit module does not output an excitation signal to the ultrasonic probe 21. When the trigger signal is high-level, the corresponding non-trigger signal is low-level; conversely, when the trigger signal is low-level, the corresponding non-trigger signal is high-level. It should be noted that during the tightening process of the threaded fastener, the preload is continuously measured. Therefore, the first control module will output multiple trigger signals at certain time intervals and output a non-trigger signal during the interval between two trigger signals.

[0039] In this embodiment, the integrated module includes a first control module and a second control module. The first control module is used to control the ultrasonic probe 21 to emit ultrasonic waves, and the second control module is used to calculate the preload. Compared with the single control module structure, this is beneficial for subsequent expansion to multiple ultrasonic probes 21.

[0040] In some embodiments, refer to Figure 2 The integrated module also includes a digital communication isolation circuit, through which the first control module and the second control module are connected for communication. The digital communication isolation circuit is used to isolate the transmission of digital signals between the first and second control modules, effectively preventing interference signals such as noise and surges from the data bus or other circuits from entering the first or second control module, thereby avoiding interference or damage to sensitive circuits and protecting the circuitry.

[0041] In some embodiments, refer to Figure 5The digital communication isolation circuit includes a first dual-channel digital isolator, which is electrically connected to the first transmitting end and the first receiving end of the first control module, and is also electrically connected to the second transmitting end and the second receiving end of the second control module.

[0042] The first dual-channel digital isolator is Figure 5 In the U8 module, the first transmitting end of the first control module is the MCU-TX terminal, the first receiving end of the first control module is the MCU-RX terminal, the second transmitting end of the second control module is the FPGA-TX terminal, and the second receiving end of the second control module is the FPGA-RX terminal. The second control module includes terminal block JP3.

[0043] The voltage input terminal VDDA of the first dual-channel digital isolator U8 is connected to a 3.3V DC voltage, specifically the output terminal of the second-stage step-down circuit in the voltage conversion circuit. The first signal channel output terminal VO1 of the first dual-channel digital isolator U8 is connected to the MCU-RX terminal of the first control module, and the second signal channel input terminal VI2 of the first dual-channel digital isolator U8 is connected to the MCU-TX terminal of the first control module. The common terminal between the voltage output terminal VDDB of the first dual-channel digital isolator U8 and pin 1 of terminal JP2 is connected to the output terminal of the second-stage isolation circuit in the isolation power supply circuit, i.e., connected to a 3.3V isolation voltage. The first signal channel input terminal VI1 of the first dual-channel digital isolator U8 is connected to the FPGA-TX terminal of the second control module through pin 2 of terminal JP2, and the second signal channel output terminal VO2 of the first dual-channel digital isolator U8 is connected to the FPGA-RX terminal of the second control module through pin 3 of terminal JP2.

[0044] In this embodiment, the first dual-channel digital isolator U8 has a signal transmission rate of up to 150Mbps and an isolation voltage of up to 5KV, thus exhibiting excellent electromagnetic interference immunity and low power loss. It can achieve high noise immunity and high insulation capability, effectively preventing noise, surges, and other interference signals from the data bus or other circuits from entering the first or second control module, thereby avoiding interference or damage to sensitive circuits and protecting the circuit.

[0045] In some embodiments, refer to Figure 5 The digital communication isolation circuit also includes a second dual-channel digital isolator, which is electrically connected to the input and output terminals of the second control module and to the enable and input terminals of the first control module.

[0046] The second dual-channel digital isolator is Figure 5In U9, the enable terminal of the first control module is the Enable terminal, the input terminal of the first control module is the Input terminal, and the input / output terminal of the second control module is the FPGA-IO terminal. The second control module includes terminal block JP3.

[0047] The voltage input terminal VDDA of the second dual-channel digital isolator U9 is connected to a 3.3V DC voltage, specifically the output terminal of the second-stage step-down circuit in the voltage conversion circuit. The first signal channel output terminal VO1 of the second dual-channel digital isolator U9 is connected to the Enable terminal of the first control module via a series resistor R2. This first signal channel output terminal is also connected to the Input terminal of the first control module via a series resistor R3. The common terminal between the voltage output terminal VDDB of the second dual-channel digital isolator U9 and pin 1 of terminal JP3 is connected to the output terminal of the second-stage isolation circuit in the isolation power supply circuit, which provides a 3.3V isolation voltage. The first signal channel input terminal VI1 of the second dual-channel digital isolator U9 is connected to the FPGA-IO terminal of the second control module via pin 2 of terminal JP3.

[0048] In this embodiment, the signal transmission rate of the second dual-channel digital isolator U9 can reach 150Mbps and has an isolation voltage of up to 5KV. Therefore, it has excellent electromagnetic interference immunity and low power loss, and can achieve high noise immunity and high insulation capability. It can effectively prevent noise, surge and other interference signals on the data bus or other circuits from entering the first control module or the second control module, thereby avoiding interference or damage to sensitive circuits and protecting the circuit.

[0049] In some embodiments, refer to Figure 2 The integrated module also includes a receiving circuit module and an analog-to-digital converter module electrically connected to the receiving circuit module. The receiving circuit module receives the ultrasonic echo signal output by the ultrasonic probe 21, processes the ultrasonic echo signal, and outputs a second signal to the analog-to-digital converter module. The analog-to-digital converter module performs analog-to-digital conversion processing on the second signal and outputs a third signal to the second control module. The first control module sends a trigger signal to the transmitting circuit module and simultaneously sends a first signal to the second control module. The second control module receives the first signal and determines the first time the first signal is received; receives the third signal and determines the second time the third signal is received; determines the echo time based on the first time, the second time, and a preset transmission time; determines the preload based on the echo time and sends the preload to the tool controller.

[0050] The first signal is a digital signal, which can be transmitted in isolation using a digital communication isolation circuit. The first signal can be either a high-level or low-level signal. The first time is the time point at which the second control module receives the first signal, expressed as: hour:minute:second.decimal part of seconds, with the decimal part of seconds retained to 6 digits. The ultrasonic echo signal and the second signal are both analog signals, while the third signal is a digital signal obtained by analog-to-digital conversion of the second signal. The second time is the time point at which the second control module receives the third signal, expressed as: hour:minute:second.decimal part of seconds, with the decimal part of seconds retained to 6 digits. Determining the echo time based on the first time, the second time, and the preset transmission time includes using the difference between the second time and the first time and the preset transmission time as the echo time. The echo time equals the time difference between the second time and the first time minus the preset transmission time. The preset transmission time is the time difference between the time the second control module receives the third signal and the time the receiving circuit module receives the ultrasonic echo signal output by the receiving ultrasonic probe 21, measured under experimental conditions. The analog-to-digital conversion module is specifically a high-speed AD module. In this embodiment, the echo time is determined based on the first time, the second time, and the preset transmission time, which ensures the accuracy of the calculated echo time.

[0051] In some embodiments, refer to Figure 4 and Figure 6 The receiving circuit module includes at least one operational amplifier, and the transmitting circuit module includes a boost chip.

[0052] The receiver circuit module can contain one, two, three, or more operational amplifiers. The second signal is an analog signal obtained by amplifying the ultrasonic echo signal. The operational amplifier amplifies the ultrasonic echo signal to ensure that the amplified ultrasonic echo signal, i.e., the second signal, can be accurately sampled in the analog-to-digital conversion module. A boost converter chip can be referenced. Figure 4 The U6 in the circuit is a boost chip used to increase the input voltage to a high voltage signal that can drive the ultrasonic probe 21 to emit, i.e., the excitation signal mentioned above, thereby providing sufficient energy to the ultrasonic probe 21.

[0053] Reference Figure 6The receiving circuit module includes three operational amplifiers: a first operational amplifier U7A, a second operational amplifier U7B, and a third operational amplifier U7C. The receiving circuit module includes a capacitor C35. The front end of capacitor C35 is connected to the TX / RX terminal of the ultrasonic probe 21. The TX / RX terminal of the ultrasonic probe 21 is connected to ground via a resistor R27. The rear end of capacitor C35 is connected to the negative input terminal of operational amplifier U7A via a resistor R36. The output terminal of the first operational amplifier U7A is connected to the positive input terminal of the second operational amplifier U7B via a capacitor C43. The common terminal between resistor R36 and the negative input terminal of the first operational amplifier U7A is connected to the front end of capacitor C43 via a resistor R37. The positive power supply pin of the first operational amplifier U7A is connected to the output terminal of the first-stage step-down circuit in the voltage conversion circuit, i.e., connected to 5V. This positive power supply pin is also connected to ground via a capacitor C41. The negative power supply pin of the first operational amplifier U7A is grounded. The rear end of capacitor C35 is connected to the positive input terminal of the first operational amplifier U7A after series resistor R22. The rear end of capacitor C35 is also connected to the common terminal between the cathode of the first diode and the anode of the second diode of switching diode D9. The cathode of the second diode of switching diode D9 is connected to the output terminal of the first stage buck circuit in the voltage conversion circuit. The anode of the first diode of switching diode D9 is grounded. The rear end of resistor R22 is connected to the ground after series resistor R28. The rear end of resistor R22 is also connected to the ground after series capacitor C37. The rear end is also connected to the ground after series resistors R23, R31 and R34 in sequence.

[0054] Resistor R31 is connected to ground via capacitor C42 in series at its rear end. Resistor R35 is then connected to capacitor C43 at its rear end, which is the common terminal between the positive input terminal of the second operational amplifier U7B. Resistor R32 is then connected to the negative input terminal of the second operational amplifier U7B at its rear end. Resistor R33 is then connected to the output terminal of the second operational amplifier U7B at its rear end. The common terminal between the output terminal of the second operational amplifier U7B and resistor R33 is connected to the positive input terminal of the third operational amplifier U7C via capacitor C40 in series.

[0055] The rear end of resistor R23 is connected in series with resistor R20 and then to the output of the first-stage step-down circuit in the voltage conversion circuit, i.e., connected to 5V. A capacitor C38 is connected in series with this rear end and then grounded. Resistors R24 and R29 are connected in series with this rear end and then grounded. A capacitor C39 is connected in series with the rear end of resistor R24 ​​and then grounded. A resistor R25 is connected in series with this rear end and then to the positive input of the third operational amplifier U7C. A resistor R19 is connected in series with this rear end and then to the negative input of the third operational amplifier U7C. Resistors R17, R6, and C13 are connected in series with the rear end of resistor R19 and then grounded. The output of the third operational amplifier U7C is connected to the front end of resistor R6, and the rear end of resistor R6 is connected to the SMA connector J1 in the high-speed AD module.

[0056] In this embodiment, the receiving circuit module first amplifies the reflected ultrasonic echo signal by 14 times through transimpedance amplification, and then amplifies the transimpedance amplified signal by 20 times through in-phase amplification. This not only increases the frequency of the signal, but also facilitates subsequent signal processing.

[0057] Reference Figure 4 The ground terminal GND of the boost chip U6 is grounded. The common terminal of the enable pin CE and the power supply voltage input terminal VDD of the boost chip U6 is connected in series with the ferrite bead FB2 and then connected to the output terminal of the first-stage buck circuit. The common terminal is also connected in series with capacitor C28 and then grounded. The common terminal between the ferrite bead FB2 and the output terminal of the first-stage buck circuit in the voltage conversion circuit is connected in series with capacitor C30 and then grounded.

[0058] The feedback pin FB of the boost converter chip U6 is connected to the first control module's U2-29 terminal after being connected in series with resistor R11. The first control module's U2-29 terminal is also connected to ground after being connected in series with Zener diode Z1 and capacitor C25. The feedback pin FB of the boost converter chip U6 is also connected to ground after being connected in series with resistor R15. This feedback pin FB is also connected in series with the front end of resistor R13. The rear end of resistor R13 is connected to ground after being connected in series with capacitor C27. This rear end is also connected to the cathode of fast recovery diode D8. The anode of fast recovery diode D8... The drain of MOSFET Q2 is connected to the gate of MOSFET Q2, which is connected to the external control terminal EXT of boost chip U6. The source of MOSFET Q2 is grounded. The positive terminal of fast recovery diode D8 is connected in series with inductor L1 and ferrite bead FB3 and then connected to the output terminal of the first-stage buck circuit in the voltage conversion circuit. The common terminal of inductor L1 and ferrite bead FB3 is connected in series with capacitor C33 and then grounded. This common terminal is also connected in series with inductor C34 and then grounded. The common terminal between ferrite bead FB3 and the output terminal of the first-stage buck circuit in the voltage conversion circuit is connected in series with capacitor C32 and then grounded.

[0059] The feedback pin FB is connected in series with the front end of resistor R13. The rear end of resistor R13 is connected in series with resistor R12 and capacitor C26 and then connected to the TX / RX terminal of ultrasonic probe 21. The TX / RX terminal of ultrasonic probe 21 is connected in series with resistor R14 and then grounded. Pin 2 of ultrasonic probe 21 is grounded. The common terminal of resistor R12 and capacitor C26 is connected to the drain of MOSFET Q3. The source of MOSFET Q3 is grounded. The gate of MOSFET Q3 is connected to the Enable terminal of the first control module. The gate is also connected in series with resistor R26 and then grounded.

[0060] In this example, the trigger signal is a low-level signal, issued by the first control module and output from its Enable terminal. The boost converter U6 boosts the 5V voltage to 95V. When the trigger signal (low-level signal) output from the Enable terminal reaches the gate of MOSFET Q3, the MOSFET is not turned on, and the boost converter U6 outputs a 95V excitation signal to the ultrasonic probe 21. When the non-trigger signal (high-level signal) output from the Enable terminal reaches the gate of MOSFET Q3, the MOSFET is turned on, and the 95V excitation signal output by the boost converter U6 is not output to the ultrasonic probe 21.

[0061] In some embodiments, refer to Figure 2 The integrated module also includes a power supply module, which includes a power input terminal, a voltage conversion circuit, and an isolation power supply circuit. The voltage conversion circuit is electrically connected to the power input terminal and to the first control module, and the isolation power supply circuit is electrically connected to the power input terminal and to the second control module.

[0062] The power input terminal is used to connect to an input power source, such as a 12V DC power supply. The voltage conversion circuit converts the input power voltage to a voltage suitable for the first control module, thus powering the first control module. The isolation power supply circuit converts the input power voltage to a voltage suitable for the second control module, thus powering the second control module and achieving regulated output under electrical isolation. In this embodiment, by configuring independent voltage conversion and isolation power supply circuits, power isolation between the first and second control modules can be achieved.

[0063] The voltage conversion circuit includes a first-stage buck circuit and a second-stage buck circuit connected in series. The input terminal of the first-stage buck circuit is connected to the power supply terminal. The voltage at the output terminal of the first-stage buck circuit and the input terminal of the second-stage buck circuit are both 5V. The output terminal of the second-stage buck circuit outputs the working voltage to the first control module, which is 3.3V.

[0064] Reference Figure 7 The first-stage buck circuit includes a buck chip U0. The input of buck chip U0 is connected to a 12V input power supply, and a capacitor C2 is connected in series with this input before grounding. The output of buck chip U0 is connected in series with a ferrite bead FB1, outputting a 5V voltage. A capacitor C3 is connected in series with the rear end of ferrite bead FB1 before grounding, followed by another capacitor C4 and then another capacitor C5 before grounding. The ground terminal of buck chip U0 is also grounded. This first-stage buck circuit can stably convert a 12V DC voltage to a 5V DC voltage.

[0065] Reference Figure 8The second-stage buck circuit includes a buck chip U1. The input terminal of buck chip U1 is connected in series with a ferrite bead FB4 and then to the rear end of FB4. This input terminal is also connected in series with a capacitor C8 and then grounded. The output terminal of buck chip U1 outputs a 3.3V voltage. This output terminal is also connected in series with a capacitor C6 and then grounded, and with another capacitor C7 connected in series, it is also grounded. The ground terminal of buck chip U1 is grounded. This second-stage buck circuit can stably convert a 5V DC voltage to a 3.3V DC voltage.

[0066] The isolation power supply circuit includes a first-stage isolation circuit and a second-stage isolation circuit connected in series. The input terminal of the first-stage isolation circuit is connected in parallel with the input terminal of the first-stage buck converter. The output terminal of the second-stage isolation circuit provides an isolation voltage of 3.3V to the first control module. This isolation power supply circuit is used to isolate and protect the FPGA data acquisition and processing module.

[0067] Reference Figure 9 The first-stage isolation circuit includes a converter U3. The voltage input terminal VIN of converter U3 is connected to a 12V input power supply, and a capacitor C9 is connected in series with this input terminal before grounding. The voltage output terminal VO of converter U3 outputs a 5V isolation voltage, and a capacitor C10 is connected in series with this output terminal before grounding. This first-stage isolation circuit can stably convert a 12V DC voltage to a 5V isolation voltage.

[0068] Reference Figure 10 The second-stage isolation circuit includes a voltage regulator chip U5. The voltage input terminal VIN of the voltage regulator chip U5 is connected to the voltage output terminal VOUT of the converter U3. The voltage output terminal VOUT of the voltage regulator chip U5 outputs a 3.3V isolation voltage, which is grounded after being connected in series with a capacitor C11. The second-stage isolation circuit can stably convert the 5V isolation voltage to a 3.3V isolation voltage.

[0069] The process of tightening threaded fasteners using the above-mentioned fastening system may include: S1, the fastening sleeve is fitted onto the head of the threaded fastener, so that when the output shaft of the fastening tool rotates, the threaded fastener can be driven to rotate synchronously through the sleeve body 1 in the fastening sleeve, thereby realizing the action of the threaded fastener. S2, Press the main switch on the fastening tool to send a start signal to the tool controller; S3, the tool controller controls the fastening tool to tighten the threaded fastener according to the set parameters, and sends a signal to the first control module through the second control module to measure the current preload of the threaded fastener; S4. After receiving the signal, the first control module sends a trigger signal to the transmitting circuit module, causing the transmitting circuit module to output an excitation signal to the ultrasonic probe 21 to control the ultrasonic probe 21 to emit ultrasonic waves, and simultaneously sends a first signal to the second control module; the ultrasonic probe 21 captures the reflected ultrasonic waves and generates an ultrasonic echo signal, the receiving circuit module receives the ultrasonic echo signal and amplifies it, and the amplified ultrasonic echo signal, which is the second signal, is output to the analog-to-digital conversion module; S5, the analog-to-digital conversion module converts the received amplified ultrasonic echo signal into a digital signal, namely the third signal, and sends the digital signal to the second control module; S6, the second control module determines the first time when the first signal is received, and the third time when the digital signal is received, and determines the echo time based on the first time, the second time, and the preset transmission time, and determines the preload based on the echo time, and outputs the preload to the tool controller; S7, the tool controller controls the fastening tool to keep running or stop running based on the received preload force; if it stops running, the current threaded fastener tightening task is completed; if it keeps running, it returns to step S3.

[0070] In some embodiments, refer to Figures 11 to 13 The fastening sleeve also includes a sleeve body 1 and an angle compensation structure; the angle compensation structure includes a first piece having a concave spherical surface and a second piece having a convex spherical surface that mates with the concave spherical surface. The second piece can swing relative to the first piece around the center of the convex spherical surface. The first piece is movably connected to the sleeve body 1 along the axial direction of the sleeve body 1, and the second piece is fixedly connected to the outer periphery of the ultrasonic probe 21. When the fastening sleeve mates with the threaded fastener, the first elastic member 31 applies an elastic force toward the second mating part 131 to the first piece, causing the ultrasonic probe 21 to abut against the threaded fastener.

[0071] The sleeve body 1 also has a second mating part 131 opposite to the first mating part 111, and the second mating part 131 is used to mate with a threaded fastener. The first mating part 111 and the second mating part 131 are arranged opposite each other along the axial direction of the sleeve body 1, and the axial direction of the sleeve body 1 can be referenced. Figure 12 and Figure 13 The direction indicated by arrow A. Threaded fasteners can be bolts, screws, etc. The preferred fastening tool is an electric tightening gun, and the preferred threaded fastener is a bolt. When a tightening sleeve is used in conjunction with an electric tightening gun, the work efficiency is high.

[0072] The second mating portion 131 is specifically used for insertion and engagement with the head of a threaded fastener. The first elastic member 31 is located on the side of the angle compensation structure facing the first mating portion 111. As an example, the second mating portion 131 has a mating groove 1311 for insertion and engagement with the head of the threaded fastener. As another example, the second mating portion 131 is a second insertion protrusion for insertion and engagement with a groove on the head of the threaded fastener.

[0073] The connection between the second component and the ultrasonic probe 21 can be achieved through threaded connection, interference fit, bonding, welding, etc. The ultrasonic probe 21 is located inside the sleeve body 1 and rotates with the sleeve body 1. The second component rotates with the ultrasonic probe 21. As an example, the angle compensation structure is a fisheye bearing 4, with the first component being the outer ring 41 of the fisheye bearing and the second component being the inner ring 42 of the fisheye bearing. As another example, the angle compensation structure includes multiple ball-head connection structures, each including a first component and a second component, arranged circumferentially around the sleeve body 1.

[0074] In this embodiment, during the tightening process of the threaded fastener, the second mating part 131 engages with the threaded fastener, and the first elastic element 31 applies a spring force toward the second mating part 131 to the first element, causing the ultrasonic probe 21 to abut against the threaded fastener. This ensures that the ultrasonic probe 21 and the head of the threaded fastener are effectively in contact, thereby ensuring the measurement accuracy of the preload of the threaded fastener. Through the setting of the angle compensation structure, the ultrasonic probe 21 can swing at a small angle relative to the sleeve body 1, thus adapting to the small-angle tilt of the head end face of the threaded fastener. This improves the measurement accuracy of the preload of the threaded fastener, enabling the fastening system to be applied to scenarios requiring high measurement accuracy of the preload of the threaded fastener. It avoids probe contact failure due to a small-angle tilt of the head end face of the threaded fastener, thus affecting measurement accuracy.

[0075] In some embodiments, refer to Figures 12 to 15 The angle compensation structure is a fisheye bearing 4. The first part is the outer ring 41 of the fisheye bearing 4, which rotates with the sleeve body 1. The second part is the inner ring 42 of the fisheye bearing 4.

[0076] The inner ring 42 has a convex spherical outer surface, while the outer ring 41 has a concave spherical inner surface. The inner ring 42 is interference-fitted onto the outer periphery of the ultrasonic probe 21. The sleeve body 1 includes a third sleeve component 13. When the third sleeve component 13 has a first mounting hole 132, the outer ring 41 is movably connected to the first mounting hole 132 along the axial direction of the sleeve body 1. The outer ring 41 can rotate with the rotation of the sleeve body 1. The sidewall of the first mounting hole 132 may be provided with a groove, and the outer ring 41 may be provided with a protrusion that is embedded in the groove to ensure that the outer ring 41 rotates with the rotation of the sleeve body 1. In this embodiment, the fisheye bearing 4 has a simple structure and is easy to install.

[0077] In some embodiments, refer to Figure 12 , Figure 13 and Figure 15 The fastening sleeve also includes a second elastic element 32, pointing from the first mating part 111 to the second mating part 131. The first elastic element 31, the angle compensation structure, and the second elastic element 32 are arranged in sequence. A mating groove 1311 is provided on the second mating part 131. When the mating groove 1311 is not mated with the threaded fastener, both the first elastic element 31 and the second elastic element 32 are in a compressed state. The second elastic element 32 applies a spring force towards the first mating part 111 to the first part. The ultrasonic probe 21 protrudes from the bottom wall of the mating groove 1311 away from the detection surface 211 of the first mating part 111. When the mating groove 1311 is mated with the threaded fastener, both the first elastic element 31 and the second elastic element 32 are in a compressed state, and the ultrasonic probe 21 abuts against the threaded fastener.

[0078] Specifically, the mating groove 1311 is used for inserting the head of the threaded fastener, that is, the head of the threaded fastener is inserted into the mating groove 1311. When the mating groove 1311 is engaged with the head of the threaded fastener, the threaded fastener rotates with the rotation of the sleeve body 1, that is, when the sleeve body 1 rotates, it can drive the threaded fastener to rotate synchronously.

[0079] The head of the threaded fastener is hexagonal; correspondingly, the mating groove 1311 is hexagonal, a star-shaped polygon with twelve points, etc. (Refer to...) Figure 22 The mating groove 1311 is preferably a star-shaped polygon with twelve corners. In this case, before the head of the threaded fastener is inserted into the mating groove 1311, only a small angle needs to be rotated to align the head of the threaded fastener with the mating groove 1311, which can improve the operating efficiency.

[0080] When the mating groove 1311 is not engaged with the head of the threaded fastener, the detection surface 211 of the ultrasonic probe 21 protrudes from the bottom wall of the mating groove 1311, and the ultrasonic probe 21 does not extend beyond the entire mating groove 1311. During the insertion of the head of the threaded fastener into the mating groove 1311, the threaded fastener will cause the ultrasonic probe 21 to retract a small distance towards the first mating part 111, increasing the elastic potential energy of the first elastic element 31, thereby enabling the detection surface 211 of the ultrasonic probe 21 to effectively fit with the head of the threaded fastener.

[0081] The direction from the first mating part 111 to the second mating part 131 can be referenced. Figure 12 and Figure 13 The direction indicated by arrow B. The second elastic element 32 is a component capable of providing elastic force, such as a coil spring, wave spring, etc. The second elastic element 32 and the first elastic element 31 form the elastic component 3. In this embodiment, the first elastic element 31 and the second elastic element 32 work together to reduce impact and vibration on the ultrasonic probe 21; the second elastic element 32 allows the threaded fastener to push back the ultrasonic probe 21 with a small thrust; in summary, it can protect the ultrasonic probe 21 and extend its service life.

[0082] In some embodiments, refer to Figure 12 , Figure 13 and Figure 16 The sleeve body 1 includes a first sleeve 11, a second sleeve 12, and a third sleeve 13 that are detachably connected in sequence; a first mating part 111 is located at the end of the first sleeve 11 away from the third sleeve 13, and a second mating part 131 is located at the end of the third sleeve 13 away from the first mating part 111; the third sleeve 13 has a first mounting hole 132, and a first elastic member 31, an angle compensation structure, and part of the ultrasonic probe 21 are located in the first mounting hole 132; the second sleeve 12 has a second mounting hole 121, and part of the ultrasonic probe 21 is located in the second mounting hole 121.

[0083] The first mounting hole 132 communicates with the mating groove 1311, and the second mounting hole 121 communicates with the first mounting hole 132. The first sleeve 11, the second sleeve 12, and the third sleeve 13 are sequentially arranged in the direction from the first mating part 111 to the second mating part 131. The second elastic member 32 is also located within the first mounting hole 132. The first mounting hole 132 is a circular hole and is coaxial with the third sleeve 13. The second mounting hole 121 is a circular hole and is coaxial with the second sleeve 12. In this embodiment, the first sleeve 11, the second sleeve 12, and the third sleeve 13 are sequentially detachably connected, facilitating assembly and disassembly. Furthermore, operators can replace a single sleeve according to actual needs without replacing the entire sleeve body 1.

[0084] The first mounting hole 132 specifically communicates with the mating groove 1311 through a through hole, and a second stepped surface 137 is formed at the junction of the first mounting hole 132 and the through hole. The second sleeve 12 also has a connecting hole 123, and a first stepped surface 128 is formed at the junction of the second mounting hole 121 and the connecting hole 123. The first elastic member 31 is located between the first stepped surface 128 and the angle compensation structure, with one end of the first elastic member 31 abutting against the first stepped surface 128 and the other end abutting against the first member of the angle compensation structure. The second elastic member 32 is located between the second stepped surface 137 and the angle compensation structure, with one end of the second elastic member 32 abutting against the first member of the angle compensation structure and the other end abutting against the second stepped surface 137.

[0085] In some embodiments, refer to Figure 14 , Figures 17 to 20 The first sleeve 11 has a connecting groove 112, and the second sleeve 12 includes a connecting part 122, which is inserted into the connecting groove 112. The first sleeve 11 has a first threaded hole 113, which communicates with the connecting groove 112. A first tightening member 14 is threaded into the first threaded hole 113, which is used to tighten the connecting part 122.

[0086] The connecting groove 112 has at least one arcuate groove wall 1121 and at least one flat groove wall 1122. Correspondingly, the connecting part 122 includes at least one arcuate outer wall 1221 and at least one flat outer wall 1222. After the connecting part 122 is inserted into the connecting groove 112, the arcuate outer wall 1221 fits against the arcuate groove wall 1121, and the flat groove wall 1122 fits against the flat outer wall 1222. This ensures the coaxiality of the connection between the first sleeve 11 and the second sleeve 12, and also ensures the reliability of torque transmission, making the fastening sleeve durable. As an example, there are four arcuate groove walls 1121 and four flat groove walls 1122, arranged alternately around the circumference of the first sleeve 11.

[0087] The number of first threaded holes 113 can be one, two, three, four, etc., and the number of first clamping members 14 can be one, two, three, four, etc. The first clamping member 14 can be a first set screw. As an example, the number of first threaded holes 113 is one, and the first threaded hole 113 is formed on one of the planar groove walls 1122. After the first clamping member 14 clamps the connecting part 122, the other planar groove wall 1122 opposite to the planar groove wall 1122 abuts against the planar outer wall 1222.

[0088] Before the connecting part 122 is inserted into the connecting groove 112, the first clamping member 14 is rotated to move it outward until it no longer protrudes from the groove wall of the connecting groove 112. After the connecting part 122 is inserted into the connecting groove 112, the first clamping member 14 is rotated to move it inward until it presses against the connecting part 122. After the first clamping member 14 presses against the connecting part 122, it is rotated to move it outward until it no longer protrudes from the groove wall of the connecting groove 112. At this point, the first clamping member 14 no longer presses against the connecting part 122, allowing the replacement of the first sleeve 11. In this embodiment, the connection between the first sleeve 11 and the second sleeve 12 is reliable and stable, and the connection operation is simple.

[0089] In some embodiments, refer to Figure 11 and Figure 12 The fastening sleeve also includes a hollow outer shell 5, and the sleeve body 1 is rotatably connected to the outer shell 5. The outer shell 5 has a first through hole 511 corresponding to the first tightening member 14. The fastening sleeve also includes a plug 9, which is inserted into the first through hole 511 to seal the first through hole 511.

[0090] The outer casing 5 is specifically a cylindrical structure, with both ends of the sleeve body 1 protruding beyond the outer casing 5. The sleeve body 1 is rotatable relative to the outer casing 5, and a bearing 10 is provided between the outer casing 5 and the sleeve body 1. There can be two bearings 10, one located between one end of the outer casing 5 and the first sleeve member 11, and the other located between the other end of the outer casing 5 and the third sleeve member 13, to ensure smooth and reliable rotation of the sleeve body 1. This bearing 10 can be a deep groove ball bearing. When manually tightening threaded fasteners, the outer casing 5 can be held by the operator for easy manual tightening.

[0091] The outer casing 5 can be formed by mating two semi-circular outer casing sub-parts 51 together, so as to facilitate the assembly of the outer casing 5 onto the outside of the sleeve body 1. The two outer casing sub-parts 51 are detachably connected for easy assembly and disassembly. The connection method of the two outer casing sub-parts 51 can be screw connection, snap-fit, etc. As an example, there is one first clamping member 14 and one first through hole 511, which is formed on one of the outer casing sub-parts 51.

[0092] The first through hole 511 can be circular, and the plug 9 can be a T-shaped plug, a cylindrical plug, etc. Under normal circumstances, sealing the first through hole 511 with the plug 9 prevents dust from entering the fastening sleeve through the first through hole 511. There can be various types of first sleeve components 11, each with different quick-connect grooves 1111 to accommodate different fastening tools. By replacing different first sleeve components 11, the fastening sleeve can be made universal.

[0093] When it is necessary to replace the first set of cylindrical parts 11, first remove the plug 9, then pass the tool used to rotate the first clamping member 14 through the first through hole 511, and rotate the first clamping member 14 with the tool to move the first clamping member 14 outward until the first clamping member 14 no longer protrudes from the groove wall of the connecting groove 112. At this time, the first clamping member 14 is not clamped to the connecting part 122, and the replacement of the first set of cylindrical parts 11 can be realized. In this embodiment of the application, the replacement of the first set of cylindrical parts 11 can be realized without removing the outer shell 5, and the replacement operation of the first set of cylindrical parts 11 is convenient.

[0094] In some embodiments, refer to Figures 19 to 21 The second sleeve 12 has a connecting hole 123 at one end opposite to the first sleeve 11, which communicates with the second mounting hole 121. The third sleeve 13 includes a boss 133, which is inserted into the connecting hole 123. The second sleeve 12 includes a plurality of first protrusions 124, which are arranged circumferentially around the connecting hole 123. A first groove 125 is provided between two adjacent first protrusions 124. The third sleeve 13 has a second groove 135 that mates with each of the first protrusions 124. The third sleeve 13 also includes a second protrusion 134 that mates with the first groove 125. The first protrusions 124 are detachably connected to the third sleeve 13 by a first locking member, and / or the second protrusions 134 are detachably connected to the second sleeve 12 by a second locking member.

[0095] The connecting hole 123 is a circular hole, coaxial with the second mounting hole 121, and its diameter is larger than that of the second mounting hole 121. The boss 133 is an annular boss, coaxial with the first mounting hole 132. The boss 133 protrudes from multiple second protrusions 134. By inserting the boss 133 into the connecting hole 123, the coaxiality of the second sleeve 12 and the third sleeve 13 can be ensured.

[0096] The number of first grooves 125 is equal to the number of first protrusions 124. The number of first protrusions 124 can be 2 to 6, correspondingly, the number of first grooves 125 is 2 to 6. Preferably, the multiple first protrusions 124 are evenly arranged around the circumference of the connecting hole 123. The number of second protrusions 134 is equal to the number of first grooves 125, and the number of second grooves 135 is equal to the number of first protrusions 124. Each of the multiple second grooves 135 corresponds one-to-one with each of the multiple first protrusions 124, and each of the multiple second protrusions 134 corresponds one-to-one with each of the multiple first grooves 125. The multiple first protrusions 124 are respectively inserted into the multiple second grooves 135, and the multiple second protrusions 134 are respectively inserted into the multiple first grooves 125 to ensure the reliability of torque transmission and make the fastening sleeve durable.

[0097] The first and second locking components can be screws, studs, clips, etc. As an example, the first protrusion 124 is detachably connected to the third sleeve 13 via the first locking component. The first locking component is a screw. The first protrusion 124 has a first connecting hole 126, and the third sleeve 13 has a third threaded hole 136. The first locking component passes through the first connecting hole 126 and is threadedly connected to the third threaded hole 136.

[0098] In some embodiments, refer to Figure 11 , Figure 12 and Figure 17 The first mating part 111 is provided with a quick-connect groove 1111, which is used to mate with a fastening tool; the first mating part 111 is also provided with a second threaded hole 114, which communicates with the quick-connect groove 1111, and a second tightening member 15 is internally threaded into the second threaded hole 114, which is used to tighten the fastening tool.

[0099] The quick-connect slot 1111 can be square in shape. It is used for inserting the output shaft of an electric tightening gun or the connector of a manual wrench. In other words, the output shaft of the electric tightening gun or the connector of the manual wrench is inserted into the quick-connect slot 1111. The center line of the quick-connect slot 1111 is on the same straight line as the axis of the first sleeve 11.

[0100] The number of second threaded holes 114 is preferably multiple, for example, two or four, etc., and correspondingly, the number of second tightening members 15 is two or four, etc. As an example, any two opposite groove walls of the quick-connect groove 1111 are provided with second threaded holes 114. As another example, all four groove walls of the quick-connect groove 1111 are provided with second threaded holes 114. The second tightening member 15 can be a second set screw. In the embodiments of this application, the fastening sleeve is reliably connected to the fastening tool through the second tightening member 15, and the connection operation is simple, making it very convenient to install the fastening sleeve onto the fastening tool.

[0101] Before inserting the output shaft of the electric tightening gun or the connector of the manual wrench into the quick-connect groove 1111, rotate the second clamping member 15 to move the second clamping member 15 outward until the second clamping member 15 no longer protrudes from the groove wall of the quick-connect groove 1111. After inserting the output shaft of the electric tightening gun or the connector of the manual wrench into the quick-connect groove 1111, rotate the second clamping member 15 to move the second clamping member 15 inward until the second clamping member 15 clamps the output shaft of the electric tightening gun or the connector of the manual wrench.

[0102] In some embodiments, refer to Figure 11 , Figure 12 , Figure 13 and Figure 16The ultrasonic probe 21 is electrically connected to the probe wire 22. The second sleeve 12 has a second through hole 127 that communicates with the second mounting hole 121. An electric slip ring 6 is provided between the second sleeve 12 and the outer shell 5. The probe wire 22 passes through the second through hole 127 and is electrically connected to the electric slip ring 6. The fastening sleeve also includes a fixed lead wire 7, which passes through the side wall of the outer shell 5 and is electrically connected to the electric slip ring 6.

[0103] The ultrasonic probe 21 and probe wire 22 together form probe assembly 2. The slip ring 6 includes a slip ring rotor 61 and a slip ring stator 62. The slip ring rotor 61 is electrically connected to the slip ring stator 62 and can rotate relative to the slip ring stator 62. The slip ring rotor 61 is interference-fitted onto the outer circumference of the second sleeve 12 and rotates with the rotation of the sleeve body 1. The slip ring stator 62 is fixedly connected inside the outer casing 5. The probe wire 22 includes a vertical section and a bent section. The vertical section is located within the second mounting hole 121, and the bent section passes through the second through hole 127 and is electrically connected to the slip ring rotor 61. A fixed lead wire 7 is electrically connected to the slip ring stator 62. The fixed lead wire 7 is also electrically connected to the transmitting circuit module and the receiving circuit module.

[0104] The slip ring 6 is an electrical connector used to transmit power and signals in rotating equipment. By using the slip ring 6, stable power and signal transmission can be achieved during continuous rotation, the problems of tangling or breakage of the fixed lead wire 7 and probe wire 22 can be avoided, and the durability of the fastening sleeve can be improved.

[0105] The outer casing 5 has a third through hole 512, and a sealing sleeve 8 is installed inside the third through hole 512. The lead wire 7 is fixed and passes through the sealing sleeve 8 and is interference-fitted with the sealing sleeve 8. The sealing sleeve 8 serves to prevent dust and water from entering the interior of the outer casing 5.

[0106] Secondly, embodiments of this application provide a preload control method applied to the fastening system provided in the first aspect. The preload control method includes: Receive the first signal and determine the first time the first signal is received; Receive the third signal and determine the second time the third signal was received; The echo time is determined based on the first time, the second time, and the preset transmission time, and the preload is determined based on the echo time. Output preload to the tool controller so that the tool controller controls the fastening tool to keep running or stop running based on the preload. Specifically, the preload control method described above is executed by the second control module in the fastening system. The first signal is sent simultaneously with the trigger signal sent by the first control module in the integrated module. The trigger signal is used to cause the transmitting circuit module to output an excitation signal to the ultrasonic probe. The third signal is obtained by processing the ultrasonic echo signal output by the ultrasonic probe.

[0107] The first time is the time when the second control module receives the first signal, expressed as: hour:minute:second.decimal part of seconds, with the decimal part of seconds retained to 6 digits. The second time is the time when the second control module receives the third signal, expressed as: hour:minute:second.decimal part of seconds, with the decimal part of seconds retained to 6 digits.

[0108] The echo time is the time it takes for the ultrasonic wave emitted by the ultrasonic probe 21 to propagate axially through the threaded fastener to the distal end and return; that is, the time difference between the time the ultrasonic probe 21 emits the ultrasonic wave and the time it captures the returning ultrasonic wave. Determining the preload of the threaded fastener based on the echo time includes: calculating the preload stress of the threaded fastener based on the echo time, and determining the preload of the threaded fastener based on the preload stress and the cross-sectional area of ​​the threaded fastener. The preload of the threaded fastener is the preload stress multiplied by the cross-sectional area of ​​the threaded fastener. The calculated preload can retain a preset number of decimal places, which can be one, two, etc.

[0109] Controlling the operation of the fastening tool based on preload includes: if the preload is greater than or equal to a preset target preload, the fastening tool stops operating; if the preload is less than the preset target preload, the fastening tool continues operating. Stopping the fastening tool also means stopping the motor within the fastening tool, thus preventing the output shaft from rotating. Maintaining operation of the fastening tool means keeping the motor within the fastening tool running, thus keeping the output shaft rotating.

[0110] Thirdly, embodiments of this application provide a readable storage medium storing a computer program, which, when executed by a processor, implements the preload control method provided in the second aspect.

[0111] Computer-readable storage media can be any usable medium that a computer can read, or a data storage device such as a server or data center that integrates one or more usable media. Usable media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state drives), etc.

[0112] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0113] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims. All of these forms are within the protection scope of this application.

Claims

1. A fastening system, characterized in that, The device includes a fastening sleeve, a fastening tool, and an integrated module. The fastening sleeve includes an ultrasonic probe, and the fastening tool includes a tool controller. Both the ultrasonic probe and the tool controller are electrically connected to the integrated module. The fastening sleeve cooperates with the fastening tool and is used to cooperate with the threaded fastener. The fastening sleeve also includes a first elastic element, which is used to cause the ultrasonic probe to abut against the threaded fastener. The integrated module is used to control the ultrasonic probe to emit ultrasonic waves and receive and process ultrasonic echo signals. It is also used to determine the echo time, determine the preload of the threaded fastener based on the echo time, and send the preload to the tool controller. The tool controller is used to control the fastening tool to keep running or stop running based on the preload.

2. The fastening system according to claim 1, characterized in that, The fastening sleeve also includes a sleeve body and an angle compensation structure; The angle compensation structure includes a first piece having a concave spherical surface and a second piece having a convex spherical surface that mates with the concave spherical surface. The second piece can swing relative to the first piece about the center of the convex spherical surface. The first piece is movably connected to the sleeve body along the axial direction of the sleeve body. The second piece is fixedly connected to the outer periphery of the ultrasonic probe. When the fastening sleeve engages with the threaded fastener, the first elastic element applies an elastic force toward the threaded fastener to the first element.

3. The fastening system according to claim 1, characterized in that, The integrated module includes a first control module, a transmitting circuit module, and a second control module. The transmitting circuit module is electrically connected to the first control module, and the first control module is communicatively connected to the second control module. The first control module is used to send a trigger signal to the transmitting circuit module so that the transmitting circuit module outputs an excitation signal to the ultrasonic probe to control the ultrasonic probe to emit ultrasonic waves; the second control module is used to determine the echo time, determine the preload of the threaded fastener based on the echo time, and send the preload to the tool controller.

4. The fastening system according to claim 3, characterized in that, The integrated module also includes a digital communication isolation circuit, through which the first control module and the second control module are communicatively connected.

5. The fastening system according to claim 4, characterized in that, The digital communication isolation circuit includes a first dual-channel digital isolator, which is electrically connected to the first transmitting end and the first receiving end of the first control module, and electrically connected to the second transmitting end and the second receiving end of the second control module.

6. The fastening system according to any one of claims 3 to 5, characterized in that, The integrated module further includes a receiving circuit module and an analog-to-digital converter module electrically connected to the receiving circuit module; The receiving circuit module is used to receive the ultrasonic echo signal output by the ultrasonic probe, process the ultrasonic echo signal and output a second signal to the analog-to-digital conversion module, and the analog-to-digital conversion module is used to perform analog-to-digital conversion processing on the second signal and output a third signal to the second control module. The first control module is used to send the trigger signal to the transmitting circuit module and simultaneously send a first signal to the second control module. The second control module is used to receive the first signal and determine a first time when the first signal is received; receive the third signal and determine a second time when the third signal is received; and determine the echo time based on the first time, the second time, and a preset transmission time. The preload is determined based on the echo time, and the preload is sent to the tool controller.

7. The fastening system according to claim 6, characterized in that, The receiving circuit module includes at least one operational amplifier, and the transmitting circuit module includes a boost converter chip.

8. The fastening system according to any one of claims 3 to 5, characterized in that, The integrated module also includes a power module, which includes a power input terminal, a voltage conversion circuit, and an isolation power circuit. The voltage conversion circuit is electrically connected to the power input terminal and to the first control module. The isolation power supply circuit is electrically connected to the power input terminal and to the second control module.

9. A method for controlling preload, characterized in that, The preload control method, applied to the fastening system as described in any one of claims 1 to 8, comprises: Receive a first signal and determine the first time the first signal is received; wherein the first signal is sent simultaneously by the first control module in the integrated module sending a trigger signal, and the trigger signal is used to cause the transmitting circuit module to output an excitation signal to the ultrasonic probe; Receive a third signal and determine a second time when the third signal is received; wherein the third signal is obtained by processing the ultrasonic echo signal output by the ultrasonic probe; The echo time is determined based on the first time, the second time, and the preset transmission time, and the preload of the threaded fastener is determined based on the echo time. The preload is output to the tool controller so that the tool controller controls the fastening tool to keep running or stop running based on the preload.

10. A readable storage medium, characterized in that, The readable storage medium stores a computer program that, when executed by a processor, implements the preload control method as described in claim 9.

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