Tool holder and monitoring method for tool wear self-sensing based on multi-source triboelectric signals

Abstract

The application discloses a tool holder based on multi-source triboelectric signal and a monitoring method, and belongs to the technical field of machine tool cutters and intelligent monitoring equipment for states, which comprises a main structure, a rotating speed monitoring assembly, a vibration monitoring assembly, a signal processing and transmission module; the main structure comprises a rotatable main shaft, the rotating speed monitoring assembly is used for sensing the rotating speed of the main shaft and converting the rotating speed into a first electric signal, and the signal is used for power supply and extracting the rotating speed fluctuation characteristics reflecting the stability of the cutting process; the vibration monitoring assembly is used for sensing the multi-dimensional vibration in the machining process and converting the multi-dimensional vibration into a second electric signal, and the signal is used for power supply and extracting the vibration time domain and frequency domain characteristics which are strongly related to the tool wear degree; the signal processing and transmission module comprises a rectifier circuit, an energy storage unit, a signal processing unit and a signal transmission unit, and the signal processing unit and the signal transmission unit work cooperatively and jointly form a tool wear intelligent diagnosis module.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of machine tool tool and state intelligent monitoring equipment, and particularly relates to a tool wear self-aware tool holder based on multi-source triboelectric signals and a monitoring method. BACKGROUND

[0002] In the process of mechanical manufacturing towards intelligentization and digitization, the machining process state perception and intelligent monitoring of numerical control machine tools are key links. Among them, the tool, as the executive component directly involved in cutting, its wear state directly affects the quality, precision and surface integrity of the machined workpiece, and is also the core basis for predicting tool life, optimizing machining parameters and ensuring production safety. Real-time and accurate monitoring of tool wear state is of great significance for improving intelligent manufacturing level and reducing production cost.

[0003] At present, tool wear monitoring methods mainly include direct method and indirect method. The direct method (such as optical microscope measurement) needs to stop detection and cannot realize online monitoring. The indirect method is realized by monitoring physical signals related to wear, mainly including vibration signals, acoustic emission signals, spindle current signals, etc. The traditional method is to install external sensors such as accelerometers and acoustic emission sensors on the machine tool or workpiece, which has the problems of complex wiring, easy to be disturbed by the machining environment, limited installation position leading to signal attenuation, etc. In addition, these external sensors usually need external power supply, and their power consumption and volume limit their integration and application on high-speed rotating tool holders.

[0004] In recent years, the friction nanogenerator technology provides a new solution for the development of self-driven sensors. This technology can directly convert mechanical motion (such as vibration and rotation speed) into electrical signals, thereby realizing the perception of mechanical state, and has self-power supply capability, which is expected to solve the bottleneck of power supply and integration of traditional sensors. At present, some researches have applied friction nanogenerators to monitor the vibration or rotation speed of machine tools, but the functions are mostly limited to single parameter monitoring of the running state of machine tools (such as whether it is machining, high or low rotation speed), and have not yet been able to deeply mine and integrate the deep feature information contained in these self-generated signals related to the progressive wear process of tools.

[0005] In summary, there is a lack of a solution in the prior art that can be deeply integrated with the tool holder, does not need external power supply, and can intelligently diagnose the tool wear state through multi-source information fusion. Therefore, the present application provides a tool wear self-aware tool holder based on multi-source triboelectric signals and a tool wear monitoring method. The tool holder realizes online real-time monitoring and intelligent diagnosis of tool wear state by real-time perception and fusion of multi-source triboelectric signals such as machine tool spindle rotation state and cutting vibration. SUMMARY

[0006] The purpose of the present application is to solve the problems existing in the above technical field, and provide a tool holder based on multi-source triboelectric signal for tool wear self-sensing and a monitoring method, which synchronously collects spindle speed and machining vibration signals through a triboelectric nanogenerator unit integrated in the tool holder, and realizes online real-time diagnosis and early warning of tool wear state based on fusion analysis of multi-source triboelectric signals.

[0007] The tool holder based on multi-source triboelectric signal for tool wear self-sensing comprises:

[0008] The main structure, the rotating speed monitoring assembly, the vibration monitoring assembly, the signal processing and transmission module;

[0009] The main structure comprises a tool holder main body, a protective shell, a positioning ring, a bottom cover plate, a top cover plate, a positioning mechanism, a mounted tool, a deep groove ball bearing, an oil retaining ring, a lip-shaped sealing ring, an O-shaped sealing ring, a shaft and a bearing washer.

[0010] The positioning mechanism comprises a positioning pin, a positioning nut, an adjusting pad and a positioning mechanism fixing bolt.

[0011] The lower end of the protective shell is coaxially fixed to the bottom cover plate, and the tool holder main body is axially connected with the two.

[0012] During use, the protective shell is fixed, and the tool holder main body is mounted with a tool at the lower end.

[0013] The rotating speed monitoring assembly comprises an electrode layer mounting ring, a friction layer mounting ring, a first electrode layer, a first friction layer, a cylindrical roller and a flexible structure.

[0014] The electrode layer mounting ring is mounted on the inner top surface of the protective shell through the flexible structure, and the lower end of the electrode layer mounting ring is fixed to the first electrode layer.

[0015] The lower end of the first electrode layer is uniformly provided with protruding electrodes.

[0016] The friction layer mounting ring is fixed to the tool holder main body, and the friction layer mounting ring is uniformly provided with cylindrical grooves opposite to the protruding electrodes, and the cylindrical roller covered by the first friction layer is mounted in the cylindrical grooves.

[0017] When the friction layer mounting ring rotates with the tool holder main body, the protruding electrodes periodically contact and separate from the first friction layer, forming a first triboelectric nanogenerator unit, and generating a first electric signal.

[0018] The positioning mechanism comprises a positioning pin, a positioning nut, an adjusting pad and a positioning mechanism fixing bolt.

[0019] After the protective shell, the positioning ring, the bottom cover plate and the circuit board mounted in the protective shell are connected by bolts, the positioning mechanism is fixed, and the tool holder does not rotate during the machining process of the machine tool.

[0020] The top cover plate of the main body structure is located at the uppermost end of the main body structure, has a threaded through hole on the side surface, and is fixed with the tool handle main body through a bolt; the top of the positioning ring is provided with a first groove for embedding the deep groove ball bearing and axially fixing the deep groove ball bearing through the lower end surface of the top cover plate; the top of the positioning ring is provided with a second groove for embedding the top cover plate, and the second groove is further provided with an oil screen ring mounting groove for mounting the oil screen ring; the bottom of the positioning ring is provided with a threaded hole, and the positioning ring is connected with the protective shell through the middle through hole and fixed through a bolt; the top of the bottom cover plate is provided with a third groove and a fourth groove, the third groove is used for mounting the lip-shaped sealing ring, and the fourth groove is used for mounting the deep groove ball bearing, and the bottom cover plate is further provided with a boss, a plurality of threaded holes are arranged on the side surface of the boss, the bottom cover plate can be embedded into the bottom of the protective shell through the boss, and the bottom cover plate is fixed through a bolt;

[0021] The vibration monitoring assembly comprises a retainer, a first housing, a levitation magnet, a fixed magnet, a coil, a second friction layer, and a second electrode layer;

[0022] The first housing is fixedly connected to the upper end surface of the bottom cover plate, and a plurality of coils are wound on the outer side of the first housing;

[0023] The retainer is fixedly connected to the tool handle main body and located in the first housing;

[0024] The fixed magnets are fixedly connected to the upper and lower ends of the retainer, respectively;

[0025] The levitation magnet is slidably arranged on the outer side of the retainer;

[0026] The levitation magnet and the fixed magnets on the upper and lower sides form a magnetic levitation structure;

[0027] The second friction layer is located on the outer side cylindrical surface of the levitation magnet, and the second electrode layer is located on the inner wall column of the first housing;

[0028] The second friction layer and the second electrode layer form a second friction nanometer power generation unit, and when the levitation magnet vibrates, a second electric signal is generated.

[0029] The signal processing and transmission module comprises a rectifier circuit, an energy storage unit signal processing unit, and a signal transmission unit, which are electrically connected with the rotation speed monitoring assembly and the vibration monitoring assembly.

[0030] The rectifier circuit can convert alternating current generated by the first electric signal and the second electric signal into direct current to supply energy to the system;

[0031] The signal processing unit comprises a pulse trigger circuit and a signal feature extraction unit, which can extract feature parameters related to the tool wear state from the first electric signal and the second electric signal;

[0032] The signal transmission unit comprises a wireless transmission module, which can wirelessly transmit the extracted characteristic parameters and original electric signals to an external terminal.

[0033] The flexible structure is composed of a central mounting ring and flexible hinges around the central mounting ring, the flexible hinges are uniformly arranged at the ends and fixed on the upper end surface of the electrode layer mounting ring.

[0034] The central mounting ring is fixed on the inner top surface of the protection shell coaxially upward.

[0035] The first electrode layer is connected with the signal processing and transmission module through a wire.

[0036] When the first friction layer is an electronegative material and the first electrode layer is an electropositive material, the relative rotation friction of the two can form a single-electrode type friction nanogenerator.

[0037] The retainer and the first shell are made of a material that is not affected by the magnet;

[0038] The fixed magnet and the suspended magnet are both annular structures.

[0039] The retainer and the first shell form a retainer slide rail, and the suspended magnet slides in the retainer slide rail.

[0040] The suspended magnet and the fixed magnets on the upper and lower sides are arranged in opposite polarities.

[0041] The second electrode layer and the coil are connected with the signal processing and transmission module through wires, respectively.

[0042] The protection shell top is fixed with a positioning ring, and the outer extension arm end of the positioning ring is fixed with a positioning mechanism.

[0043] Another object of the present application is to provide a tool wear self-sensing tool holder monitoring method based on multi-source friction electric signals, which adopts the tool wear self-sensing tool holder based on multi-source friction electric signals described above, and comprises the following steps:

[0044] Step S1: signal synchronous acquisition and self-power supply:

[0045] The first electric signal generated by the rotation speed monitoring assembly and the second electric signal generated by the vibration monitoring assembly are synchronously acquired;

[0046] The first electric signal and the second electric signal are converted into direct current by a rectifier circuit to supply power to the entire monitoring system;

[0047] Step S2: signal preprocessing and feature extraction:

[0048] The signal feature extraction unit pre-processes (such as filtering, noise reduction) the original signal and performs feature extraction: extracting fluctuation features of main shaft speed stability from the first electric signal, and extracting vibration features reflecting vibration intensity and time-frequency characteristics from the second electric signal; the extracted features include "speed fluctuation rate", "vibration RMS value", "high frequency band energy proportion" and other feature parameters;

[0049] Step S3: feature fusion and intelligent diagnosis:

[0050] The signal features extracted by the signal feature extraction unit are input into a pre-trained tool wear diagnosis model, and the model outputs a real-time wear state classification result of the tool;

[0051] The wear state classification result at least includes three levels of normal, slight wear and severe wear;

[0052] Step S4: state information wireless transmission and early warning:

[0053] The wear state classification result is wirelessly transmitted to an external terminal, and the system is intervened according to the diagnosis result.

[0054] The tool wear diagnosis model can be a classification model trained based on a support vector machine, a decision tree or a neural network algorithm.

[0055] The application provides a tool holder for tool wear self-sensing based on multi-source triboelectric signals and a monitoring method, and belongs to the technical field of intelligent tool state monitoring equipment for machine tools, and comprises a main structure, a speed monitoring assembly, a vibration monitoring assembly, a signal processing and transmission module; the main structure comprises a rotatable main shaft, and the speed monitoring assembly is used for sensing the speed of the main shaft and converting it into a first electric signal, which is used for power supply and extracting speed fluctuation features reflecting cutting process stability; the vibration monitoring assembly is used for sensing multi-dimensional vibration in the machining process and converting it into a second electric signal, which is used for power supply and extracting vibration time domain and frequency domain features strongly related to tool wear degree; the signal processing and transmission module comprises a rectifier circuit, an energy storage unit, a signal processing unit and a signal transmission unit, and the signal processing unit and the signal transmission unit work cooperatively and jointly constitute a tool wear intelligent diagnosis module.

[0056] Compared with the prior art, the application has the following beneficial effects:

[0057] 1. Real-time and intelligent diagnosis of tool wear is realized: the application of the triboelectric signal is improved from the machine tool state monitoring level to the tool health diagnosis level; by deeply mining the stability characteristics of the rotation speed signal and the frequency spectrum characteristics of the vibration signal, and carrying out fusion analysis, the wear state of the tool (such as normal, slight wear, and severe wear) can be judged in real time and accurately, which provides direct data support for realizing predictive maintenance.

[0058] 2. Self-driving and high integration in a true sense: the system is completely powered by the built-in triboelectric nanogenerator unit, without external power supply or battery, solving the wiring problem and energy bottleneck; all sensing, power supply, processing and transmission units are integrated in the tool holder, which is compact in structure and does not change the original structure of the machine tool, and has strong applicability.

[0059] 3. Information multiplexing, one machine with multiple functions: the same set of triboelectric power generation unit realizes "energy collection" and "signal sensing" functions at the same time, and the same signal (such as vibration signal) is used to extract multiple features (such as time domain and frequency domain), which maximizes the use of hardware resources and information value, and realizes complex functions with simple system.

[0060] 4. High diagnosis reliability: by fusing rotation speed and vibration information for comprehensive judgment, compared with the method of relying only on single vibration signal, the interference such as processing parameter mutation can be effectively eliminated, and the accuracy and robustness of tool wear diagnosis are significantly improved. BRIEF DESCRIPTION OF DRAWINGS

[0061] Figure 1 Figure 1 is an internal specific structure diagram of the tool wear self-sensing tool holder based on multi-source triboelectric signal in the application;

[0062] Figure 2 Figure 2 is an overall structure axial side view of the tool wear self-sensing tool holder based on multi-source triboelectric signal in the application;

[0063] Figure 3 Figure 3 is an exploded structure diagram of the rotation speed monitoring assembly of the tool wear self-sensing tool holder based on multi-source triboelectric signal in the application;

[0064] Figure 4 Figure 4 is a schematic diagram of the relative position and connection mode of the rotation speed monitoring assembly and the vibration monitoring assembly of the tool wear self-sensing tool holder based on multi-source triboelectric signal in the application;

[0065] Figure 5 Figure 5 is a specific structure diagram of the vibration monitoring assembly of the tool wear self-sensing tool holder based on multi-source triboelectric signal in the application (part A of the local enlarged view); Figure 4

[0066] Figure 6 ​The overall sectional view of the tool holder for tool wear self-sensing based on multi-source triboelectric signals of the application;

[0067] Figure 7 The axial side view of the positioning ring in the main structure of the tool holder for tool wear self-sensing based on multi-source triboelectric signals of the application;

[0068] Figure 8 The monitoring method framework flow chart of the tool holder for tool wear self-sensing based on multi-source triboelectric signals of the application.

[0069] In the drawings:

[0070] 1. Main structure; 101. Tool holder main body; 102. Protective shell; 103. Positioning ring; 104. Bottom cover plate; 105. Top cover plate; 106. Positioning mechanism; 1061. Positioning pin; 1062. Positioning nut; 1063. Adjustment pad; 1064. Positioning mechanism fixing bolt; 108. Deep groove ball bearing; 109. Oil retaining ring; 110. Lip seal ring; 111. O-ring; 112. Shaft sleeve; 113. Bearing washer; 1021. Side screw; 1022. Bottom plate fixing screw; 107. Tool;

[0071] 2. Rotational speed monitoring assembly; 201. Electrode layer mounting ring; 202. Friction layer mounting ring; 2021. Rotational speed detection fixing bolt hole; 203. First electrode layer; 204. First friction layer; 205. Cylindrical roller; 206. Flexible structure;

[0072] 3. Vibration monitoring assembly; 301. Retainer; 302. First housing; 303. Suspended magnet; 304. Fixed magnet; 305. Coil; 306. Second friction layer; 307. Second electrode layer;

[0073] 4. Signal processing and transmission module. DETAILED DESCRIPTION

[0074] Example 1:

[0075] Please refer to the attached Figures 1-7 The tool holder for tool wear self-sensing based on multi-source triboelectric signals comprises a main structure 1, a rotational speed monitoring assembly 2, a vibration monitoring assembly 3, and a signal processing and transmission module 4.

[0076] The main structure 1 comprises a tool holder main body 101, a protective shell 102, and a bottom cover plate 104.

[0077] The lower end of the protective shell 102 is coaxially fixed to the bottom cover plate 104, and the tool holder main body 101 is axially connected to the two.

[0078] During use, the protective shell 102 is fixed, and the tool holder main body 101 is installed with a tool 107 at the lower end.

[0079] The rotation speed monitoring component 2 comprises an electrode layer mounting ring 201, a friction layer mounting ring 202, a first electrode layer 203, a first friction layer 204, a cylindrical roller 205, a flexible structure 206;

[0080] The electrode layer mounting ring 201 is mounted on the inner top surface of the protective shell 102 through the flexible structure 206, and the lower end is fixedly connected with the first electrode layer 203;

[0081] The lower end of the first electrode layer 203 is uniformly provided with protruding electrodes;

[0082] The friction layer mounting ring 202 is fixedly connected with the shank body 101, and a cylindrical groove opposite to the protruding electrodes is uniformly arranged on the friction layer mounting ring 202, and the cylindrical roller 205 covered by the first friction layer 204 is mounted in the cylindrical groove;

[0083] When the friction layer mounting ring 202 rotates with the shank body 101, the protruding electrodes periodically contact and separate from the first friction layer 204, thereby forming a first friction nano power generation unit to generate a first electric signal;

[0084] The vibration monitoring component 3 comprises a retainer 301, a first shell 302, a suspended magnet 303, a fixed magnet 304, a coil 305, a second friction layer 306, and a second electrode layer 307;

[0085] The first shell 302 is fixedly connected with the upper end surface of the bottom cover plate 104, and a plurality of coils 305 are wound on the outer side of the first shell 302;

[0086] The retainer 301 is fixedly connected with the shank body 101, and is located in the first shell 302;

[0087] The fixed magnets 304 are respectively fixedly connected with the upper and lower ends of the retainer 301;

[0088] The suspended magnet 303 is slidably arranged on the outer side of the retainer 301;

[0089] The suspended magnet 303 and the fixed magnets 304 on the upper and lower sides form a magnetic suspension structure;

[0090] The second friction layer 306 is located on the outer side cylindrical surface of the suspended magnet 303, and the second electrode layer 307 is located on the inner wall column of the first shell 302;

[0091] The second friction layer 306 and the second electrode layer 307 form a second friction nano power generation unit, and when the suspended magnet 303 vibrates, a second electric signal is generated.

[0092] The signal processing and transmission module 4 comprises a rectifier circuit, an energy storage unit signal processing unit and a signal transmission unit, which are electrically connected with the rotation speed monitoring assembly 2 and the vibration monitoring assembly 3;

[0093] The rectifier circuit can convert alternating current generated by the first electric signal and the second electric signal into direct current to supply energy for the system;

[0094] The signal processing unit comprises a pulse trigger circuit and a signal feature extraction unit, which can extract feature parameters related to the tool wear state from the first electric signal and the second electric signal;

[0095] The signal transmission unit comprises a wireless transmission module, which wirelessly transmits the extracted feature parameters and the original electric signal to an external terminal, so as to facilitate subsequent real-time tool wear state monitoring through a tool wear diagnosis model.

[0096] The flexible structure 206 is composed of a central mounting ring and flexible hinges around the central mounting ring, the flexible hinges are uniformly arranged at the ends and are fixed to the upper end surface of the electrode layer mounting ring 201;

[0097] The central mounting ring of the flexible structure 206 is coaxially fixed to the inner top surface of the protective shell 102 upwardly;

[0098] The lower end of the electrode layer mounting ring 201 is bonded with a "disc-shaped" first electrode layer 203;

[0099] The rotation speed detection fixing bolt hole 2021 is arranged on the lower boss of the friction layer mounting ring 202, and is fixed to the middle part of the tool shank body 101 through a bolt;

[0100] The first electrode layer 203 is connected with the signal processing and transmission module 4 through a wire;

[0101] When the friction layer mounting ring 202 rotates with the tool shank body 101, the protruding electrode and the cylindrical roller 205 wrapped with the first friction layer 204 periodically contact and separate, forming the first friction nanometer power generation unit and generating a first electric signal; the rotation speed monitoring assembly has the function of converting the rotation speed signal of the main shaft driving the tool shank into an electric signal.

[0102] When the first friction layer 204 is an electronegative material and the first electrode layer 203 is an electropositive material, the relative rotation friction of the two can form a single-electrode friction nanometer generator.

[0103] The retainer 301 and the first shell 302 are made of a material that is not affected by a magnet;

[0104] The lower flange plate of the first shell 302 is coaxially fixed to the upper end surface of the bottom cover plate 104 through a bolt;

[0105] The fixed magnet 304 and the levitation magnet 303 are annular structures;

[0106] The retainer 301 and the first shell 302 form a retainer slide rail, and the levitation magnet 303 is slidably arranged in the retainer slide rail;

[0107] The levitation magnet 303 and the fixed magnets 304 on the upper and lower sides are arranged in opposite polarities, forming a magnetic levitation structure;

[0108] The second electrode layer 307 and the coil 305 are respectively connected to the signal processing and transmission module 4 through wires;

[0109] The vibration monitoring assembly has the function of converting the vibration signal when the tool and the workpiece surface are in contact under the machine tool processing state into an electric signal.

[0110] The second friction layer 306 is a material with negative electricity, and the second electrode layer 307 is a material with positive electricity, and the relative sliding friction between the two can form an independent layer type friction nanogenerator.

[0111] The main body structure 1 further comprises a positioning ring 103, a top cover plate 105, a deep groove ball bearing 108, an oil retaining ring 109, a positioning mechanism 106, an O-shaped sealing ring 111, a shaft sleeve 112, a bearing washer 113 and a lip-shaped sealing ring 110;

[0112] The top end of the protective shell 102 is respectively provided with a first groove and a second groove, and the bottom end is in a cylindrical sleeve structure;

[0113] The deep groove ball bearing 108 is embedded in the first groove, and the oil retaining ring 109 is embedded in the second groove;

[0114] The positioning ring 103 is fixedly connected to the top of the protective shell 102 by an internal screw, and an O-shaped sealing ring 111 is arranged in the middle part thereof;

[0115] The bottom cover plate 104 is embedded in the cylindrical sleeve at the bottom end of the protective shell 102 and is fixed by a bottom plate fixing screw 1022, and the top end thereof is respectively provided with a third groove and a fourth groove;

[0116] The shaft sleeve 112 is embedded in the third groove, and the lip-shaped sealing ring 110 is embedded in the fourth groove;

[0117] The tool shank main body 101 passes through the protective shell 102 and the bottom cover plate 104 and is axially connected to the two by the deep groove ball bearing;

[0118] The top cover plate 105 is fixedly connected to the tool shank main body 101, and the lower end annular boss thereof abuts against the inner ring of the deep groove ball bearing 108 to axially position the deep groove ball bearing 108;

[0119] The outer side boss of the top cover plate 105 is sealed with the O-shaped sealing ring 111;

[0120] The outer extension arm of the positioning ring 103 is fixed to the positioning mechanism 106 through the positioning mechanism fixing bolt 1064, and the positioning mechanism 106 includes a positioning pin 1061, a positioning nut 1062, and an adjusting pad 1063.

[0121] The signal processing and transmission module 4 is fixed to the inner wall of the protective shell 102 through the copper column and the side screw 1021.

[0122] In actual use, the outer wall of the protective shell 102 is fixed by the positioning mechanism 106 and does not rotate during the machining process of the machine tool.

[0123] In summary, the main structure is used to accommodate and fix the above-mentioned components and provide a mounting interface on the machine tool; the rotation speed monitoring component is used to sense the rotation speed of the main shaft and convert it into a first electric signal, which is used for power supply and extraction of rotation speed fluctuation characteristics reflecting the stability of the cutting process; the vibration monitoring component is used to sense the multi-dimensional vibration during the machining process and convert it into a second electric signal, which is used for power supply and extraction of vibration time domain and frequency domain characteristics strongly related to the degree of tool wear; the signal processing and transmission module includes a rectifier circuit, an energy storage unit, a signal processing unit, and a signal transmission unit, the rectifier circuit and the energy storage unit are used to convert the alternating current generated by the friction power generation unit into direct current and supply energy to the subsequent circuit, the signal processing unit is used to extract the characteristic value parameters related to tool wear from the rotation speed and vibration signals; the signal transmission unit includes a pulse trigger circuit and a wireless transmission module, which is used to wirelessly transmit the collected original signals and / or extracted characteristic signals to the upper computer or the cloud diagnosis platform; the signal processing unit (including the signal feature extraction unit) and the signal transmission unit work together to form a tool wear intelligent diagnosis module, which can realize real-time judgment of the wear state of the tool by fusing the rotation speed fluctuation characteristics and the vibration characteristics and inputting them into a pre-trained machine learning classification model to judge the wear state of the tool.

[0124] Embodiment 2:

[0125] Please refer to the attached Figure 8 The monitoring method of the tool holder based on the multi-source triboelectric signal (use method) includes the following steps:

[0126] Step S1: signal synchronous acquisition and self-power supply:

[0127] In the process of machine tool machining, the tool holder body 101 rotates; the friction layer mounting ring 202 of the rotating speed monitoring assembly 2 rotates accordingly, causing the first friction layer 204 to periodically contact and separate from the first electrode layer 203, generating a first electric signal (electric pulse signal, rotating speed signal) strictly corresponding to the rotating speed;

[0128] At the same time, the machining vibration of the tool 107 forces the suspended magnet 303 in the vibration monitoring assembly 3 to axially vibrate relative to the first shell 302, causing the second friction layer 306 to move relative to the second electrode layer 307, generating a second electric signal (vibration signal) reflecting the vibration intensity and frequency;

[0129] The two friction power generation processes simultaneously provide energy for the system, and the generated alternating current is converted into direct current by the rectifier circuit and stored in the energy storage unit to power the entire signal processing and transmission module 4.

[0130] Step S2: signal preprocessing and feature extraction:

[0131] The pulse trigger circuit of the signal processing unit captures the original electric signals of the rotating speed and vibration;

[0132] Subsequently, the signal feature extraction unit (which can be integrated into the microprocessor of the pulse trigger circuit or a separate processing chip) pre-processes (such as filtering, noise reduction) and extracts features from the original signals;

[0133] Extract the "rotating speed fluctuation rate" feature from the rotating speed signal: under the constant spindle set rotating speed, calculate the standard deviation or coefficient of variation of the actual pulse frequency; tool wear intensifies will cause the cutting force to be unstable, thus causing the spindle load to change slightly, which is reflected in the increase of the rotating speed signal fluctuation;

[0134] Extract multi-dimensional features from the vibration signal: time domain features, such as the root mean square value (RMS) of the vibration signal, which reflects the overall energy of the vibration and increases with the intensification of wear; frequency domain features, perform fast Fourier transform (FFT) on the vibration signal and extract the energy proportion of a specific frequency band (for example, the high frequency band of 1-3 kHz); tool wear will change the cutting dynamics, causing the vibration energy to be redistributed in the frequency domain, and the energy of a specific high frequency band will significantly increase.

[0135] Step S3: feature fusion and intelligent diagnosis:

[0136] Input the "rotating speed fluctuation rate", "vibration RMS value", "high frequency band energy proportion" and other feature parameters extracted in step S2 into the pre-trained tool wear diagnosis model; the model can be a classification model such as support vector machine (SVM), decision tree or lightweight neural network trained based on a large amount of historical data;

[0137] The model outputs a classification result of the current tool wear state, for example, "Normal", "Slight Wear", "Severe Wear" or "Breakage", by analyzing the fused features.

[0138] Step S4: wireless transmission of state information and early warning

[0139] The diagnosis result (e.g. "Severe Wear") and the original feature data can be sent to the upper computer, the industrial cloud platform or the on-site display through the wireless transmission module. When the diagnosis result is "Severe Wear" or "Breakage", the system triggers an audible and light alarm or sends a request for shutdown / tool change to the numerical control system, thereby achieving active early warning and intervention.

[0140] The above process realizes a closed loop from mechanical signal acquisition, energy self-sufficiency, to intelligent diagnosis and wireless transmission, and completes real-time, online and self-driven monitoring of the tool wear state, thereby providing key technical support for predictive maintenance in the intelligent manufacturing process.

Claims

1. A tool holder with self-sensing capability for tool wear based on multi-source triboelectric signals, characterized in that, include: Main structure (1), speed monitoring component (2), vibration monitoring component (3), signal processing and transmission module (4); The main structure (1) includes a handle body (101), a protective shell (102), a positioning ring (103), a bottom cover plate (104), and a top cover plate (105). The lower end of the protective shell (102) is fixedly connected to the bottom cover plate (104), and the upper end of the protective shell (102) and the bottom cover plate (104) are respectively axially connected to the main body of the tool holder (101); A cutting tool (107) is mounted on the lower end of the tool holder body (101). The speed monitoring component (2) includes an electrode layer mounting ring (201), a friction layer mounting ring (202), a first electrode layer (203), a first friction layer (204), a cylindrical roller (205), and a flexible structure (206). The electrode layer mounting ring (201) is mounted on the top surface inside the protective shell (102) through a flexible structure (206), and its lower end is fixed to the first electrode layer (203). Protruding electrodes are evenly distributed around the lower circumference of the first electrode layer (203); The friction layer mounting ring (202) is fixed to the tool holder body (101), and cylindrical grooves opposite to the protruding electrodes are evenly distributed on it. The cylindrical roller (205) is installed in the cylindrical groove and covers the first friction layer (204). The friction layer mounting ring (202) rotates with the tool holder body (101), and the protruding electrode periodically contacts or separates from the first friction layer (204) to form the first triboelectric nano-power generation unit and generate the first electrical signal. The positioning mechanism (106) is located on the protective shell (102); The positioning mechanism (106) includes a positioning pin (1061), a positioning nut (1062), an adjusting pad (1063), and a positioning mechanism fixing bolt (1064). The protective shell (102), positioning ring (103), bottom cover plate (104) and circuit board installed in the protective shell (102) are connected by bolts and fixed by positioning mechanism (106) and do not rotate during machine tool processing; The top cover plate (105) of the main structure (1) is located at the top of the main structure (1), and has a threaded through hole on the side. It is fixed to the tool holder body (101) by bolts. The top of the positioning ring (103) is provided with a first groove, which is used to embed the deep groove ball bearing (108) and is axially fixed to the deep groove ball bearing (108) by the lower end face of the top cover plate (105). The top of the positioning ring (103) is provided with a second groove, which is used to embed the top cover plate (105). At the same time, the second groove is also provided with an oil baffle ring mounting groove for installing the oil baffle ring (108). 09); The bottom of the positioning ring (103) is provided with a threaded hole. The positioning ring (103) is connected to the protective shell (102) through the middle through hole and is fixed by bolts; The top of the bottom cover plate (104) is provided with a third groove and a fourth groove. The third groove is used to install the lip seal ring (110) and the fourth groove is used to install the deep groove ball bearing (108). At the same time, the bottom cover plate (104) is also provided with a boss. The side of the boss is provided with several threaded holes. The bottom cover plate (104) can be embedded into the bottom of the protective shell (102) through the boss and fixed by bolts.

2. The tool wear self-sensing tool holder based on multi-source triboelectric signals according to claim 1, characterized in that: The vibration monitoring component (3) includes a cage (301), a first housing (302), a suspending magnet (303), a fixed magnet (304), a coil (305), a second friction layer (306), and a second electrode layer (307). The first housing (302) is fixed to the upper end face of the bottom cover plate (104), and a coil (305) is wound around the outer side one turn at a time. The retainer (301) is located inside the first housing (302) and is fixed to the tool holder body (101); Fixed magnets (304) are respectively fixed to the upper and lower ends of the retainer (301); The levitation magnet (303) is slidably mounted on the outside of the cage (301); The levitation magnet (303) and the fixed magnets (304) on the upper and lower sides constitute a magnetic levitation structure; The second friction layer (306) is located on the outer cylindrical surface of the levitation magnet (303), and the second electrode layer (307) is located on the inner cylindrical surface of the first housing (302); The second friction layer (306) and the second electrode layer (307) form a second triboelectric nano-power generation unit, which generates a second electrical signal when the suspending magnet (303) vibrates.

3. The tool wear self-sensing tool holder based on multi-source triboelectric signals according to claim 2, characterized in that: The signal processing and transmission module (4) includes a rectifier circuit, an energy storage unit, a signal processing unit, and a signal transmission unit, and is electrically connected to the speed monitoring component (2) and the vibration monitoring component (3).

4. The tool wear self-sensing tool holder based on multi-source triboelectric signals according to claim 3, characterized in that: The rectifier circuit converts the alternating current generated by the first and second electrical signals into direct current to power the system. The energy storage unit signal processing unit includes a pulse triggering circuit and a signal feature extraction unit, which extracts feature parameters related to the tool wear state from the first electrical signal and the second electrical signal; The signal transmission unit includes a wireless transmission module that wirelessly transmits the extracted feature parameters and the original electrical signal to an external terminal.

5. The tool wear self-sensing tool holder based on multi-source triboelectric signals according to claim 4, characterized in that: The flexible structure (206) consists of a central mounting ring and flexible hinges around it, with the ends of the flexible hinges evenly fixed to the upper surface of the electrode layer mounting ring (201). The central mounting ring is coaxially fixed to the top inner surface of the protective shell (102); The first electrode layer (203) is connected to the signal processing and transmission module (4) via wires.

6. The tool wear self-sensing tool holder based on multi-source triboelectric signals according to claim 5, characterized in that: When the first friction layer (204) is an electronegative material and the first electrode layer (203) is an electronegative material, the relative rotational friction between the two constitutes a single-electrode triboelectric nanogenerator.

7. The tool wear self-sensing tool holder based on multi-source triboelectric signals according to claim 6, characterized in that: The retainer (301) and the first housing (302) are both made of a material that is unaffected by magnets; Both the fixed magnet (304) and the levitation magnet (303) are ring-shaped structures; A retainer slide rail is formed between the retainer (301) and the first housing (302), and the suspending magnet (303) is slidably disposed in the retainer slide rail; The levitation magnet (303) and the fixed magnets (304) on the upper and lower sides are arranged with opposite polarities; The second electrode layer (307) and the coil (305) are connected to the signal processing and transmission module (4) via wires.

8. A method for monitoring tool wear self-sensing tool holders based on multi-source triboelectric signals, characterized in that: The tool wear self-sensing tool holder based on multi-source triboelectric signals as described in claim 4 includes the following steps: S1. Synchronous signal acquisition and self-powered operation: The first electrical signal generated by the speed monitoring component (2) and the second electrical signal generated by the vibration monitoring component (3) are collected synchronously. The first and second electrical signals are converted into direct current by a rectifier circuit to power the entire monitoring system. S2. Signal Preprocessing and Feature Extraction: The signal feature extraction unit preprocesses the original signal and performs feature extraction. It extracts the fluctuation features of spindle speed stability from the first electrical signal and the vibration features reflecting vibration intensity and time-frequency characteristics from the second electrical signal. The extracted features include: "speed fluctuation rate", "vibration RMS value" and "high-frequency energy ratio". S3. Feature Fusion and Intelligent Diagnosis: The signal features extracted by the signal feature extraction unit are input into the pre-trained tool wear diagnosis model, and the model outputs the real-time wear status classification results of the tool. The wear status classification results include at least three levels: normal, slight wear, and severe wear; S4. Wireless transmission of status information and early warning: The wear status classification results are wirelessly transmitted to an external terminal for diagnosis, and intervention is made in the system based on the diagnosis results.

9. The method for monitoring tool wear self-sensing tool holders based on multi-source triboelectric signals according to claim 8, characterized in that: The tool wear diagnosis model is a classification model trained based on support vector machine, decision tree, or neural network algorithms.

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