Sensor for gear strain in-situ detection and preparation method and application thereof

Abstract

The invention relates to the technical field of mechanical sensing, in particular to a sensor for gear strain in-situ detection and a preparation method and application thereof. The sensor for gear strain in-situ detection comprises a ceramic film formed by curing a polymer precursor, the electrodes are respectively connected to two ends of the ceramic film; wherein the polymer precursor is prepared from polysilazane (PSN2), titanium diboride (TiB2) and conductive carbon powder (CCP), and the polymer precursor is prepared from polysilazane (PSN2), titanium diboride (TiB2) and conductive carbon powder (CCP). The ceramic film has the characteristics of high temperature resistance and corrosion resistance, and can be arranged in a tooth root transition area (a gear stress concentration core area) to directly form a uniform sensing structure, so that in-situ monitoring of strain is realized.

Description

Technical Field

[0001] This invention relates to the field of mechanical sensing technology, specifically to a sensor for in-situ detection of gear strain, its preparation method, and its application. Background Technology

[0002] In large machinery (such as wind turbine gearboxes and offshore lifting platforms) and precision transmission systems, gears are core transmission components. Their tooth root region is prone to fatigue fracture due to long-term exposure to alternating bending strain, directly affecting the safe operation and service life of the equipment. Therefore, real-time and accurate monitoring of tooth root strain is a crucial means of assessing gear life and preventing failures.

[0003] Current gear strain monitoring technologies include traditional patch strain gauges, thin-film strain gauges, fiber optic grating sensors, and wireless testing systems. The development trend focuses on "high precision, in-situ integration, and strong adaptability." However, existing technologies still have significant room for improvement in areas such as the preparation of complex curved surfaces at the tooth root, installation stability, and process simplification.

[0004] Existing gear strain monitoring technologies suffer from several drawbacks: First, they are complex and heavily reliant on equipment. For example, some technologies require vacuum-environment layered deposition and precision laser etching, which are costly and difficult to uniformly form films on complex curved surfaces at the tooth root. Second, they are not source-end monitoring, with sensors mostly located on the gear end face, resulting in delayed strain transmission. Third, adhesive sensors have adhesive layer errors and are prone to creep and detachment at high temperatures. Fourth, they have complex structures, making installation and maintenance inconvenient, and some solutions have large sensor volumes that affect gear rotation. Fifth, they are costly and lack versatility, relying on special materials and equipment with limited adaptability. Sixth, they are not adaptable to extreme environments, with performance degrading under high-temperature and corrosive conditions. Seventh, they have poor surface adaptability, making it difficult to adapt to the curved surfaces at the tooth root, and uneven film layers affect accuracy. Summary of the Invention

[0005] Based on this, the present invention provides a sensor (strain gauge) for in-situ detection of gear strain, its preparation method and application, which solves at least one problem in the prior art.

[0006] In a first aspect, the present invention provides a sensor for in-situ detection of gear strain, comprising: Polymer-derived ceramic (PDC) films formed by curing polymer precursors. and electrodes respectively connected to both ends of the ceramic thin film; The polymer precursors include polysilazane (PSN2), titanium diboride (TiB2), and conductive carbon powder (CCP).

[0007] Secondly, the present invention provides a method for preparing the above-mentioned sensor for in-situ gear strain detection, which includes the following steps: The paper is immersed in a mixed solution containing PDMS and a curing agent, then removed and cured with PDMS, and patterned to obtain a paper-based mask with a hollowed-out pattern. The paper-based mask is attached to the surface of the gear root, and a polymer precursor is coated onto the surface of the gear root through the hollow pattern of the paper-based mask. The mask is then removed and cured to obtain a ceramic film. Electrodes were connected to both ends of the ceramic thin film to obtain a sensor for in-situ gear strain detection.

[0008] Secondly, the present invention provides the application of the above-mentioned sensor for in-situ detection of gear strain in detecting gear strain.

[0009] Because of the adoption of the above technical solutions, the embodiments of the present invention have at least the following beneficial effects: (1) Using a simple in-situ integration process, without relying on high vacuum sputtering equipment or precision laser etching system, a uniform sensing structure can be directly formed in the tooth root transition area (stress concentration core area) through a flexible preparation method adapted to the tooth root arc surface, so as to realize in-situ strain monitoring; its structural design eliminates the adhesive layer and complex packaging components, eliminating the creep, hysteresis and detachment risks of traditional adhesive sensors, while shortening the strain signal transmission path, significantly reducing response delay, accurately reflecting the real-time strain changes inside the gear teeth, and simplifying the process steps, making it suitable for small and medium-sized gears and mass production scenarios; (2) The sensor used for in-situ detection of gear strain has excellent adaptability to extreme environments. The sensing structure adopts high temperature and corrosion resistant materials and integrated protection design, which can work stably for a long time under working conditions such as high temperature of about 300℃, high humidity and oil dust. In addition, its universal structural design can be adapted to gears with different modules and number of teeth, without the need for customized special modules or high cost demodulation equipment, which greatly reduces hardware and maintenance costs, and takes into account both measurement accuracy and engineering practicality. Attached Figure Description

[0010] Figure 1 This is a schematic diagram showing the position of the sensor used for in-situ gear strain detection in Embodiment 1 of the present invention.

[0011] Figure 2 This is a photograph of the sensor used for in-situ gear strain detection in Embodiment 1 of the present invention.

[0012] Figure 3 This is a photograph of the test platform in Embodiment 1 of the present invention.

[0013] Figure 4 The image shows the response curve of the sensor used for in-situ gear strain detection in Embodiment 1 of the present invention.

[0014] Figure 5 This refers to the resistance change of the sensor used for in-situ gear strain detection in Embodiment 1 of the present invention during gear meshing.

[0015] Figure 6 The resistance change of the sensor used for in-situ gear strain detection in Embodiment 1 of the present invention at different rotational speeds.

[0016] Figure 7 This is a graph showing the stability test results of the sensor used for in-situ gear strain detection in Embodiment 1 of the present invention. Detailed Implementation

[0017] The following will provide a clear and complete description of the concept and technical effects of the present invention, so as to fully explain the purpose, solution and effects of the present invention.

[0018] In gear strain sensing, the following requirements exist: (1) Simplify the preparation process, get rid of the dependence on high vacuum equipment, and realize the precise patterning of complex curved surface strain gauges at the tooth root; (2) Eliminate the influence of the adhesive layer and directly bond the sensor to the gear substrate through in-situ preparation to improve the strain transmission accuracy and long-term stability; (3) Reduce structural complexity by using low-cost materials and simple packaging; (4) Improve environmental adaptability by enhancing the sensor’s high temperature resistance, corrosion resistance and vibration resistance through ceramic treatment, so as to achieve long-term monitoring under complex working conditions; (5) Integrating the sensor into the tooth root transition zone enables in-situ monitoring of the core area of ​​stress concentration, shortens the strain signal transmission path, reduces response delay, and directly reflects the strain changes inside the gear teeth.

[0019] Therefore, the present invention aims to provide a gear tooth root in-situ integrated strain gauge technology that is simple to manufacture, low in cost, and highly adaptable to curved surfaces.

[0020] In a first aspect, the present invention provides a sensor for in-situ detection of gear strain, comprising: Polymer-derived ceramic (PDC) films formed by curing polymer precursors. and electrodes respectively connected to both ends of the ceramic thin film; The polymer precursors include polysilazane (PSN2), titanium diboride (TiB2), and conductive carbon powder (CCP).

[0021] The aforementioned ceramic thin film possesses high temperature resistance and corrosion resistance, and can be placed in the tooth root transition zone (the core area of ​​gear stress concentration) to directly form a uniform sensing structure, enabling in-situ strain monitoring. In this structure, titanium diboride in the polymer precursor acts as a cross-linking agent, while carbon powder enhances conductivity. During gear operation, the teeth experience micro-strain due to external pressure, causing the overall structure of the ceramic thin film to elongate. According to the resistance formula... R = ρ · L / S ( ρ Resistivity L For length, S (Cross-sectional area of ​​the film), length L Changes cause changes in resistance, and the magnitude of micro-strain (e.g., Δ) on the gear can be analyzed using the resistance change signal. R 0.03% corresponds to 30με).

[0022] In some optional embodiments, the ceramic film has a shape that conforms to the root of the gear. This shape is simply to facilitate the attachment of the ceramic film to the gear root, and can be determined depending on the specific gear.

[0023] In some alternative embodiments, the ceramic film is zigzag-shaped along its length. For example... Figure 1 As shown, a ceramic thin film 1 with a zigzag shape along its length is located on the gear 2. Compared to a straight shape, the zigzag shape of the ceramic thin film increases its length, which is beneficial for improving the mechanical sensing accuracy of small gears.

[0024] In some optional embodiments, the thickness of the ceramic film is 0.060-0.070 mm. Preferably, the thickness of the ceramic film is 0.065 mm.

[0025] Secondly, the present invention provides a method for preparing the above-mentioned sensor for in-situ gear strain detection, which includes the following steps: The paper is immersed in a mixed solution containing PDMS and a curing agent, then removed and cured with PDMS, and patterned to obtain a paper-based mask with a hollowed-out pattern. The paper-based mask is attached to the surface of the gear root, and a polymer precursor is coated onto the surface of the gear root through the hollow pattern of the paper-based mask. The mask is then removed and cured to obtain a ceramic film. Electrodes were connected to both ends of the ceramic thin film to obtain a sensor for in-situ gear strain detection.

[0026] In some alternative embodiments, the paper is Whatman 1 type filter paper.

[0027] In some optional embodiments, the mass ratio of PDMS to curing agent is 9:1 to 11:1. Preferably, the mass ratio of PDMS to curing agent is 10:1. The curing agent can be DC184 curing agent (methylhydrosiloxane, manufactured by Dow Corning).

[0028] In some optional embodiments, the polymer precursor comprises polysilazane (PSN2), titanium diboride (TiB2), and conductive carbon powder (CCP) in a mass ratio of 10:10:4 to 10:10:6. Preferably, the polymer precursor comprises polysilazane (PSN2), titanium diboride (TiB2), and conductive carbon powder (CCP) in a mass ratio of 10:10:5.

[0029] In some alternative embodiments, the aforementioned perforated pattern has a zigzag shape along its length.

[0030] Secondly, the present invention provides the application of the above-mentioned sensor for in-situ detection of gear strain in detecting gear strain.

[0031] The following is a typical example.

[0032] Example 1 The sensor for in-situ gear strain detection is prepared according to the following steps: (1) Preparation of paper-based photomask Weigh 3g of PDMS and 0.3g of curing agent and mix them. Stir at a constant temperature and speed of 100r / min for 10min at 25℃. Then, place the mixed PDMS solution into a vacuum chamber and evacuate at a vacuum degree of -0.15Mpa for 15min. Cut Whatman 1 type filter paper into 10mm×10mm square pieces and remove surface burrs with a scraper. Immerse the Whatman 1 type filter paper in the PDMS solution while simultaneously evacuating to eliminate internal micro-air bubbles. After immersion for 1 hour, remove it and hang it in a dark, light-protected place for 6 hours. The mask was then placed in a high-temperature drying oven and heated at 80°C for 30 minutes. After heating, the mask was allowed to cool to room temperature and its surface was cleaned with anhydrous ethanol. The mask was then laid flat on the laser processing surface and scanned using a carbon dioxide laser. The laser spot size was 0.2 mm, the scanning line width was 0.2 mm, the laser speed was 300 mm / s, the laser power was 4.5 W, the laser frequency was 20 kHz, the defocusing amount was 0 mm, and the processing was performed twice. After the laser scanning was completed, excess residue on the surface was removed with a needle tip to obtain a paper-based mask with a hollowed-out pattern. (2) Preparation of ceramic thin films Weigh 2g of polysilazane (PSN2) and 2g of titanium diboride (TiB2) powder, sonicate them at room temperature for 10 min, and stir them at 25℃ and 300 r / min for 30 min. After stirring, add 1g of carbon powder, sonicate them at room temperature for 10 min, and stir them at 25℃ and 150 r / min for 6 h to obtain a uniformly dispersed PDC precursor mixture solution. Attach a paper-based photomask with a perforated pattern to the root of the PEEK gear teeth, and use a syringe to take 3mL of the mixture. A PDC precursor mixture solution was dropped onto the cutout pattern of a paper-based photomask, allowing the PDC precursor mixture solution to fill the mask channel (cutout pattern) and transfer to the root of the PEEK gear teeth. Excess solution was removed, the paper-based photomask was removed, and the material was placed in a 175°C drying oven for 1 hour. Subsequently, it was placed in an air atmosphere and subjected to in-situ pyrolysis treatment using a CO2 laser (laser speed 1000 mm / s, laser power 4.5 W, laser frequency 20 kHz, defocusing amount 0 mm) to achieve the ceramization transformation and conductivity of the material, thus preparing a ceramic thin film at the root of the PEEK gear teeth. (3) Sensor fabrication Two copper wires are used as electrodes and connected to both ends (end A and end B) of a ceramic thin film. They are then fixed with polyimide tape (0.055 mm) to obtain a sensor for in-situ gear strain detection.

[0033] like Figure 2 As shown, Example 1 successfully fabricated a ceramic thin film on the root of a PEEK gear tooth. The specific parameters of the PEEK gear are: module 4.5, number of teeth 15 mm, thickness 15 mm, inner diameter 15 mm, and keyway size 5 mm × 3 mm, serving as the substrate for the sensor. The ceramic thin film has a grid-like structure, with an overall length of 16 mm, a width of 6 mm, a single line width of 0.6 mm, and a thickness of 0.065 mm.

[0034] like Figure 3 As shown, the sensor used for in-situ gear strain detection in Example 1 was tested using a test platform. A servo motor (model RGM5715) was fixed to the lifting platform, and the driving gear was fixed to the servo motor shaft. Torque was transmitted to the gear via the shaft and a key on the shaft. The driven gear was fixed to a vertical single-bearing seat on the lifting platform. The two gears meshed to simulate normal operation, and the servo motor was controlled by a computer to adjust its speed. The servo motor drove the gear to simulate working conditions, and the speed (75rpm-150rpm) could be adjusted by the computer. Copper wires were connected to a Keysight 34460A digital source meter via conductive slip rings to collect and output resistance signals.

[0035] The servo motor operates at speeds of 75rpm, 100rpm, 125rpm, and 150rpm, with the gear working 8 revolutions at each speed stage. The resistance value of the sensor used for in-situ gear strain detection in Example 1 is collected in real time using a Keysight 34460A digital source meter. Figure 4 The single-cycle response of the PDC within a strain range of 60 με was demonstrated, with stretching and release response times of 0.28 s and 0.35 s, respectively. After unloading, the resistance rapidly recovered to its initial value, indicating that the sensor has fast response / recovery capabilities and good reliability. Figure 5 The resistance change curve of the strain gauge during gear meshing at 125 rpm is shown. The results show that the resistance signal exhibits stable periodic fluctuations during gear meshing, and its waveform characteristics highly match the strain change law generated in the tooth root region during dynamic gear meshing. This verifies that the in-situ integrated PDC thin-film strain gauge can accurately capture the dynamic strain information during gear operation. Based on the test data, a curve showing the relationship between the relative rate of change of resistance (ΔR / R0) and time (s) is plotted. Figure 6 The results showed that, within the four stages from 75 rpm to 150 rpm, the resistance change rate increased with the increase of rotational speed, and the resistance change curves at different speeds maintained good periodicity, indicating that the strain gauge can still work stably under variable speed conditions and has the ability to sensitively detect changes in the gear running state.

[0036] Test the resistance stability at a constant rotation speed, such as Figure 7 As shown, when working at a constant speed of 100 rpm for 60 seconds, the resistance change rate of the sensor used for in-situ gear strain detection in Example 1 remained stable at around 0.005, without any obvious drift or attenuation, which fully demonstrates its excellent long-term working stability and reliability.

[0037] The above description is merely a preferred embodiment of the present invention. The present invention is not limited to the above-described embodiments. Any embodiment that achieves the technical effects of the present invention by the same or equivalent means should fall within the protection scope of the present invention. Within the protection scope of the present invention, various modifications and variations can be made to the technical solutions and / or implementation methods.

Claims

1. A sensor for in-situ detection of gear strain, characterized in that, include: Ceramic films formed by curing polymer precursors; and electrodes respectively connected to both ends of the ceramic thin film; The polymer precursors include polysilazane, titanium diboride, and conductive carbon powder.

2. The sensor for in-situ gear strain detection according to claim 1, characterized in that, The aforementioned ceramic film has a shape that fits the root of the gear.

3. The sensor for in-situ gear strain detection according to claim 1, characterized in that, The aforementioned ceramic film has a tortuous shape along its length.

4. The sensor for in-situ gear strain detection according to claim 1, characterized in that, The thickness of the aforementioned ceramic film is 0.060-0.070 mm.

5. The method for preparing a sensor for in-situ gear strain detection according to claim 1, characterized in that, Includes the following steps: The paper is immersed in a mixed solution containing PDMS and a curing agent, then removed and cured with PDMS, and patterned to obtain a paper-based mask with a hollowed-out pattern. The paper-based mask is attached to the surface of the gear root, and a polymer precursor is coated onto the surface of the gear root through the hollow pattern of the paper-based mask. The mask is then removed and cured to obtain a ceramic film. Electrodes were connected to both ends of the ceramic thin film to obtain a sensor for in-situ gear strain detection.

6. The method according to claim 5, characterized in that, The paper mentioned above is Whatman 1 type filter paper.

7. The method according to claim 5, characterized in that, The mass ratio of PDMS to curing agent is 9:1-11:

1.

8. The method according to claim 5, characterized in that, The aforementioned polymer precursors include polysilazane, titanium diboride, and conductive carbon powder in a mass ratio of 10:10:4 to 10:10:

6.

9. The method according to claim 5, characterized in that, The aforementioned openwork pattern has a zigzag shape along its length.

10. The application of the sensor for in-situ gear strain detection according to claim 1 in detecting gear strain.

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