Temperature sensor integrated with bearing and preparation method and application thereof

Abstract

The invention relates to a temperature sensor integrated with a bearing and a preparation method and application thereof, and relates to the technical field of bearing diagnos.The temperature sensor comprises a multi-layer composite film resistance grid structure, and a composite film sequentially comprises a bearing substrate, a transition seed layer, an insulating layer, a sensing layer and a wear-resistant protective layer from inside to outside; by adding the transition seed layer between the bearing substrate and the insulating layer, the binding force between the insulating layer and the bearing substrate is enhanced, the probability of sensor failure caused by large difference of thermal expansion coefficients of the insulating layer and the bearing substrate is reduced, and the use effect of the sensor is improved; in-situ real-time temperature sensing is realized by adopting a scheme of coating a film on a bearing raceway, the scheme starts from the source of a fault, an intelligent diagnosis technology and criterion based on the temperature of a bearing contact area are formed, bearing fault detection methods are enriched, forward guidance is formed for bearing design, and the bearing fault detection efficiency is improved. And a new idea is provided for an aviation high-speed light-load bearing fault diagnosis technology.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bearing diagnosis, and particularly relates to a temperature sensor integrated with a bearing, a preparation method and application thereof. BACKGROUND

[0002] As an important part in mechanical transmission, the stability of the running state of a bearing is closely related to the running state of the whole machine. In order to improve the running stability and precision of high-performance mechanical equipment, the running state of the bearing needs to be monitored in real time. According to statistics, the proportion of a series of secondary damages caused by bearing damage in the damage of rotating parts is as high as 75%. The running state diagnosis method system of aviation high-speed light-load bearings seriously depends on imports, which is not only expensive, but also needs to be returned to the original factory for analysis, and there is a risk of interruption of the whole machine or spare parts at any time. This situation has become a constraint on the development of China's bearing industry. Therefore, it is of great significance to develop a self-controllable diagnosis and evaluation technology system.

[0003] As one of the most important performance parameters of bearings, the temperature signal is a key indicator for judging the normal work of bearings. The temperature at the raceway is the key monitoring area, but at present, the temperature or temperature field change of bearings can only be monitored through the surface temperature of the inner and outer rings of the bearing or the change of the rolling contact surface after disassembly after the whole machine test, and cannot be diagnosed from the source of temperature generation, resulting in a large difference between the design and actual temperature data of the bearing and a time lag in signal transmission.

[0004] In related technologies, a Chinese patent application with the application number CN202411416079.6 discloses an in-situ integration method of an arrayed bearing temperature sensor, which comprises the following steps: first, cleaning the surface of the bearing, then depositing an insulating layer on the outer ring of the bearing by using a magnetron sputtering process, then arranging a flexible mask with an arrayed pattern on the outer ring of the bearing, arranging a thermistor sensitive layer on the insulating layer, and arranging a protective layer on the thermistor sensitive layer, so as to directly arrange the sensor on the surface of the bearing for temperature detection. However, in this way, the insulating layer is directly connected with the bearing, and the problem of sensor failure caused by the large difference in thermal expansion coefficient between the insulating layer and the bearing substrate is likely to occur, thereby reducing the use effect of the sensor. SUMMARY

[0005] The present application aims to solve the above problems, and provides a temperature sensor integrated with a bearing, a preparation method and application thereof.

[0006] The first aspect of the present application provides a temperature sensor integrated with a bearing, which adopts the following technical scheme:

[0007] The temperature sensor integrated with the bearing comprises a multilayer composite thin film resistance gate structure, and the composite thin film comprises, from inside to outside, a bearing base, a transition seed layer, an insulation layer, a sensing layer and a wear-resistant protective layer.

[0008] By adopting the technical scheme, the transition seed layer is added between the bearing base and the insulation layer to enhance the bonding force between the insulation layer and the bearing base, reduce the probability of sensor failure caused by the large difference in thermal expansion coefficients between the insulation layer and the bearing base, realize in-situ real-time temperature sensing by the bearing raceway plating scheme, and meet the requirements of wear resistance, high temperature resistance, wide temperature range and high response speed of the multilayer composite thin film to adapt to the raceway environment, thereby improving the use effect of the sensor and forming a technology and criterion for intelligent diagnosis based on the bearing contact area temperature, and enriching the bearing fault detection method.

[0009] Preferably, the transition seed layer is prepared from a nickel-chromium-aluminum-yttrium (NiCrAlY) alloy material, and the film layer has a thickness of 400-500 nm.

[0010] By adopting the technical scheme, the nickel-chromium-aluminum-yttrium alloy material is used as a four-element high-temperature thermal corrosion coating to effectively increase the thermal corrosion resistance of the bearing base and prolong the heat-resistant service life, thereby enhancing the bonding force between the insulation layer and the bearing base and effectively solving the sensor failure problem caused by the large difference in thermal expansion coefficients between the insulation layer and the bearing base.

[0011] Preferably, the insulation layer is formed by combining a thermal growth oxide (TGO) layer and an aluminum oxide (Al2O3) layer, and the film layer has a thickness of 3000-3200 nm.

[0012] By adopting the technical scheme, the TGO layer is obtained by aluminum separation and thermal oxidation treatment reaction of the transition seed layer, which is conducive to enhancing the bonding force of the film layer, and the Al2O3 can further improve the insulation performance.

[0013] Preferably, the sensing layer is prepared from platinum (Pt) material, the film layer has a thickness of 450-500 nm, and the sensing layer surface has a sensitive gate structure.

[0014] By adopting the technical scheme, the Pt material has a high temperature coefficient, and the sensing layer has good performance.

[0015] Preferably, the sensitive gate structure is a multi-fold S-shaped structure, and the effective longitudinal gate length of the sensitive gate structure is greater than 1 mm.

[0016] By adopting the technical scheme, the S-shaped structure can more accurately obtain the temperature strain signal for the temperature measurement requirement of the limited space of the bearing raceway surface, and can adapt to the small size constraint while ensuring high sensitivity, and limit the length of the effective longitudinal gate.

[0017] Preferably, the wear-resistant protective layer is prepared by using diamond-like carbon (DLC) material.

[0018] By adopting the technical scheme, the protective layer avoids friction and wear of the sensor caused by the bearing roller in operation, and oil pollution and abrasive particle pollution, and the wear-resistant protective layer is prepared by using DLC, thereby ensuring long-term operation stability of the sensitive grid in the high-stress and high-temperature environment of the bearing contact area.

[0019] The second aspect of the application provides a preparation method of a temperature sensor integrated with a bearing, comprising the following steps:

[0020] S1, sample polishing and cleaning: the working surface of the bearing raceway is subjected to grinding and polishing treatment, and the treated bearing is subjected to ultrasonic cleaning and plasma cleaning to obtain a clean bearing substrate;

[0021] S2, transition seed layer preparation: a transition seed layer is prepared on the bearing substrate of S1 by using a direct current magnetron sputtering method;

[0022] S3, insulation layer preparation: aluminum is separated from the transition seed layer deposited in S2, and thermal oxidation is performed to obtain a thermal growth oxide (TGO) layer, and then an insulation film layer material is deposited on the TGO layer by using a radio frequency magnetron sputtering method to obtain an insulation layer;

[0023] S4, sensor layer preparation: a sensing material is deposited on the insulation layer obtained in S3 by using a direct current magnetron sputtering to obtain a sensor layer;

[0024] S5, sensitive grid preparation: a sensitive grid pattern is prepared on the surface of the sensor layer obtained in S4 by using an ultra-short pulse laser;

[0025] S6, wear-resistant protective layer preparation: a wear-resistant material is deposited on the sensor layer obtained in S5 by using a plasma-assisted vapor deposition method to form a wear-resistant protective layer, thereby obtaining a temperature sensor integrated with a bearing.

[0026] By adopting the technical scheme, the transition seed layer, the insulation layer, the sensor layer and the wear-resistant protective layer are sequentially prepared on the bearing raceway surface from bottom to top by using a magnetron sputtering combined with a plasma-enhanced chemical vapor deposition plating process, the in-situ integration of the bearing temperature sensor is realized, the in-situ real-time temperature sensing is realized, the multi-layer composite thin film meets the requirements of wear resistance, high temperature resistance, wide temperature range and high response speed, and thus is suitable for the raceway environment. This scheme starts from the source of the fault, forms an intelligent diagnosis technology and criterion based on the bearing contact area temperature, enriches the bearing fault detection method, positively guides the bearing design, and also provides a new idea for the aviation high-speed light-load bearing fault diagnosis technology.

[0027] Preferably, in the technical scheme of the above preparation method, the step S1 is specifically: S1, sample polishing and cleaning: before leaving the factory, the bearing raceway surface is sequentially polished by a surface polishing machine, a precision grinding and polishing machine and a manual polishing table to perform rough polishing, manual rough polishing, semi-fine polishing and fine polishing, so that the working surface is polished into a mirror surface after a series of polishing and finishing, and the average surface roughness Ra of the working surface is better than 40nm (for bearings with a nominal diameter of less than 80mm), then the treated bearing is sequentially soaked in petroleum ether and anhydrous ethanol for 20 minutes for high-power ultrasonic cleaning, and dried by using dry nitrogen, the sample and the target material are wiped by using a disposable dust-free cloth, the target material and the sample are installed in a vacuum coating device by wearing a dust-free glove, the mechanical pump and the molecular pump are started, the chamber pressure is adjusted to 4x10 -4 Pa, then argon is slowly introduced, the ion source is started to perform plasma cleaning, and the bearing substrate is obtained after the organic contaminants on the surface of the sample are completely removed.

[0028] Preferably, in the technical scheme of the above preparation method, the step S5 is specifically: S5, sensitive gate preparation: part of the sensing layer in the composite film layer on the bearing raceway surface is accurately removed to form a sensitive gate pattern, dynamic focal point compensation is realized by a five-axis linkage machine tool combined with a 3D galvanometer, green light picosecond laser (535nm / 500fs) is selected as the laser parameter, the initial energy density is determined by a single pulse ablation threshold experiment, the actual processing energy is calibrated in combination with the film layer absorption coefficient and the spot overlap rate, multiple scans are performed at a low energy density and a high repetition frequency to realize clean peeling of the Pt film and ensure the edge quality, and the sensitive gate structure with a line width accuracy of ±5um and a relative position deviation of less than 10um is finally obtained by feedback optimization of the film layer residue and the groove morphology detected by a white light interferometer.

[0029] By adopting the above technical scheme, the preferred preparation method and steps are used to obtain a temperature sensor integrated with a bearing with higher precision.

[0030] The third aspect of the application provides application of the above-mentioned temperature sensor integrated with a bearing in temperature measurement of a bearing outer ring raceway area.

[0031] In summary, the present application has at least one of the following beneficial technical effects:

[0032] 1. By adding a transition seed layer between the bearing substrate and the insulating layer, the bonding force between the insulating layer and the bearing substrate is enhanced, the probability of sensor failure caused by large difference in thermal expansion coefficient between the insulating layer and the bearing substrate is reduced, and the use effect of the sensor is improved.

[0033] 2. The temperature sensor is integrated in situ on the bearing raceway surface by adopting magnetron sputtering combined with plasma enhanced chemical vapor deposition coating process to prepare transition seed layer, insulating layer, sensing layer and wear-resistant protective layer on the bearing raceway surface from bottom to top, realizing in-situ integration of the bearing temperature sensor, realizing in-situ real-time temperature sensing, and meeting the requirements of wear resistance, high temperature resistance, wide temperature range and high response speed, so as to adapt to the raceway environment. This scheme starts from the source of failure, forms an intelligent diagnosis technology and criterion based on the bearing contact area temperature, enriches the bearing fault detection method, provides a new idea for the design of the bearing fault diagnosis technology of the aviation high-speed light-load bearing.

[0034] 3. The sensor provided by the method can realize dynamic monitoring for temperature measurement of the bearing raceway area. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is a schematic diagram of the overall structure of the temperature sensor of the present application;

[0036] Figure 2 is a schematic diagram of the structure of a small-size resistance sensitive grid in the present application;

[0037] Figure 3 is a schematic diagram of the structure of a large-size resistance sensitive grid in the present application;

[0038] Figure 4 is a schematic diagram of the arrangement of the temperature sensor on the bearing in the present application.

[0039] Reference signs: 1, bearing base; 2, transition seed layer; 3, insulating layer; 4, sensing layer; 5, protective layer; 6, sensitive grid structure; 61, small-size sensitive grid; 62, large-size sensitive grid; 63, pin; 7, high-temperature lead wire. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical scheme and advantages of the present application more clear and understandable, the present application will be further described in detail below in combination with embodiments and drawings. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. Those skilled in the art can modify or replace equivalently without departing from the spirit and scope of the present application, which should be covered within the protection scope of the present application.

[0041] The information of reagents, instruments and equipment used in the following examples is shown in Table 1.1 and Table 1.2, all reagents and chemicals are used as received without further treatment, and other specific conditions not mentioned are carried out according to conventional conditions or manufacturer's recommended conditions, and the reagents or instruments not mentioned by manufacturer are conventional products that can be purchased on the market.

[0042] Table 1.1 Reagents and raw materials used in the information table

[0043]

[0044]

[0045] The NiCrAlY alloy target material is a cylindrical target material with a diameter of 3 inches (76.2 mm) and a thickness of 5 mm. The DLC material is prepared by plasma-assisted vapor deposition, with a bias voltage of 640 V, an acetylene flow rate of 70 scccm, a hydrogen flow rate of 10 sccm, and a deposition time of 70 min.

[0046] Table 1.2 Instrument and equipment information table used in the information table

[0047]

[0048] The chemical abbreviations used in this application are as follows:

[0049] Nickel-chromium-aluminum-yttrium (NiCrAlY) alloy material, thermal growth oxide (TGO), aluminum oxide (Al2O3), platinum (Pt) material, diamond-like carbon-based thin film (DLC) material.

[0050] I. Examples

[0051] Example 1

[0052] Referring to Figure 1 A temperature sensor integrated with a bearing includes a multi-layer composite thin film resistor gate structure. The composite thin film includes, from the inside out, a bearing substrate 1, a transition seed layer 2, an insulating layer 3, a sensing layer 4, and a wear-resistant protective layer 5.

[0053] Referring to Figure 1 The transition seed layer 2 is made of NiCrAlY alloy material with a film thickness of 400-500 nm to enhance the bonding force between the insulating layer and the bearing substrate, effectively solving the problem of sensor failure caused by the large difference in thermal expansion coefficient between the insulating layer and the bearing substrate.

[0054] Referring to Figure 1 The insulating layer 3 is formed by combining two heterogeneous materials, TGO and Al2O3. The TGO layer is obtained by aluminum extraction and thermal oxidation treatment of the transition seed layer 2, with a film thickness of 100-1100 nm, which is beneficial to enhancing the bonding force of the film layer. Al2O3 can further improve the insulation performance, with a film thickness of 2000-2100 nm.

[0055] Referring to Figure 1 The sensing layer 4 is made of Pt material with a high temperature coefficient, with a film thickness of 450-500 nm. The sensing layer 4 has a sensitive gate structure 6 on its surface.

[0056] Referring to Figure 1 , Figure 2 and Figure 3 , the embodiment provides two sizes of sensitive gate structures 6, both of which are multi-fold S-shaped structures, and the effective longitudinal gate length of the sensitive gate structure 6 is greater than 1 mm, and the sensitive gate 6 has a pin 63 at both ends, which serves as a lead electrode.

[0057] Referring to Figure 1 , Figure 2 and Figure 3 , the first sensitive gate structure provided by the embodiment is a small-size sensitive gate 61, the gate width is 4.7 mm, the gate length is 1.3 mm, and the size of the pin at both ends is 1.5 mm*1.2 mm.

[0058] Referring to Figure 1 , Figure 2 and Figure 3 , the second sensitive gate structure provided by the embodiment is a large-size sensitive gate 62, the gate width is 5.7 mm, the gate length is 1.4 mm, and the size of the pin at both ends is 1.5 mm*1.2 mm.

[0059] Referring to Figure 1 , the wear-resistant protective layer 5 is prepared by using DLC material, and the film thickness is 2 pm±0.1. The protective layer 5 is used to avoid friction and wear caused by the bearing roller in operation, and oil stain and abrasive particle pollution.

[0060] Embodiment 2

[0061] Referring to Figure 1 , Figure 2 and Figure 3 , a preparation method of a temperature sensor integrated with a bearing, comprising the following steps:

[0062] S1, sample polishing and cleaning: the bearing raceway working surface is subjected to grinding and polishing treatment, and the treated bearing is subjected to ultrasonic cleaning and plasma cleaning to obtain a clean bearing substrate 1.

[0063] Specifically, the outer ring raceway surface of the P4 precision and above deep groove ball bearing and cylindrical roller bearing is used as the machining surface, the bearing material is GCr15 high-carbon chromium bearing alloy steel, and the working surface such as raceway is subjected to grinding and polishing treatment during machining to eliminate steps, scratches, pits and the like on the surface, so as to avoid affecting the bonding force of the composite film layer and the substrate and the wear resistance of the sensor during long-term service. The metal substrate is subjected to ultrasonic cleaning to further remove surface oil stains and dirt, and subsequent additive and subtractive preparation is carried out, and the detailed steps are as follows:

[0064] In the first step, the bearing raceway surface passes through a surface polishing machine, a precision grinding and polishing machine, and a manual polishing table before leaving the factory, undergoing rough polishing, manual rough polishing, semi-finishing polishing, and fine polishing in sequence: First, a CNC surface grinder performs a 1-minute rough polishing to remove machining marks; a 2-minute manual rough polishing is performed on a manual polishing table to address the local rough spots left by the rough polishing; finally, a precision bearing polishing machine performs a 3-minute semi-finishing polishing and a 3-minute fine polishing to significantly reduce surface waviness. After completing a series of grinding and polishing, the machined surface should be polished to a mirror finish, and the average surface roughness Ra of the working surface should be better than 40nm (for bearings with a nominal diameter of less than 80mm).

[0065] In the second step, the entire bearing treated in the first step was immersed in petroleum ether and anhydrous ethanol in that order for 20 minutes of 1200W ultrasonic cleaning, and then blown dry with dry nitrogen to improve the surface quality and smoothness of the sample.

[0066] The third step is to wipe the sample and target with a disposable dust-free cloth, and install the target and sample in the vacuum coating equipment while wearing dust-free gloves; turn on the mechanical pump and molecular pump, and adjust the chamber pressure to 4x10 -4 Pa, then 100 sccm of argon was introduced, and the ion source was turned on for plasma cleaning. The bias current was set to 10A, and 15 sccm of hydrogen and 100 sccm of argon were introduced. The cleaning time was controlled to be 20 minutes. Organic contaminants on the surface of the sample (herein, the sample refers to the bearing raceway surface) were completely removed. After cleaning, a clean bearing substrate 1 was obtained. The target material here refers to the material used to prepare the transition seed layer, insulating layer, sensing layer, and protective layer.

[0067] S2. Preparation of transition seed layer: a transition seed layer 2 is prepared on the bearing substrate 1 of S1 by using a DC magnetron sputtering method.

[0068] Specifically, a NiCrAlY alloy target with a purity of 99.99% was used, with a nickel content of 67%, a chromium content of 22%, an aluminum content of 10%, and a yttrium content of 1%. The DC magnetron sputtering method is as follows: First, close the baffle above the sample and perform pre-sputtering for about 10 minutes. During the pre-sputtering, check the ignition condition of the target through the observation window. The entire annular magnetic field area of ​​the target surface is covered with a stable and uniformly bright glow. The glow is continuous and ring-shaped along the closed loop of the magnetic field. If there are no breakpoints or local dark areas, it is a normal ignition state. Then, open the baffle above the sample and use the DC magnetron sputtering method to prepare the transition seed layer 2. Set the DC power to 200W, the sputtering temperature to 450°C, the sputtering gas pressure to 0.4Pa, the sputtering time to 18 minutes, and the film thickness to 400-500nm.

[0069] S3, preparation of insulating layer: aluminum precipitation and thermal oxidation are performed on the transition seed layer 2 deposited in S2. The aluminum precipitation temperature is 1048℃ and the aluminum precipitation pressure is 8×10-4 Pa, the aluminum precipitation time is 6 hours; oxidation is carried out at 950°C under normal pressure for 12 hours to obtain a thermally grown oxide (TGO) layer, and then the insulating film material is deposited on the TGO layer by radio frequency magnetron sputtering to obtain an insulating layer 3.

[0070] Specifically, the deposited NiCrAlY alloy layer is subjected to aluminum precipitation and thermal oxidation, and the film thickness is controlled between 1000nm and 1100nm. This film layer can not only improve the insulation performance, but also enhance the bonding strength between Al2O3 and NiCrAlY. Then, the Al2O3 layer is prepared. To ensure the excellent insulation performance of the sensor at high temperatures, Al2O3 with a high melting point and stable electrical insulation performance is used as the insulating film layer material. To further improve the density of the film layer, an Al2O3 target with a purity of 99.99% is selected. The deposition time is 21h41min under an RF power supply power of 200W, a sputtering pressure of 0.3Pa, and an argon gas flow of 100sccm, and the film thickness is controlled between 2000nm and 2100nm.

[0071] S4. Preparation of sensing layer: using DC magnetron sputtering to deposit the sensing material on the insulating layer 3 obtained in S3 to obtain the sensing layer 4.

[0072] Specifically, a Pt target material with a purity higher than 99.99% was used for deposition by DC magnetron sputtering. The DC power was set to 120W and the sputtering pressure was set to 0.4Pa to ensure the bonding force. The sputtering time was 21 minutes, and the film thickness was controlled between 450-500nm.

[0073] S5. Preparation of sensitive gate: preparing a sensitive gate pattern on the surface of the sensing layer obtained in S4 by ultrashort pulse laser processing.

[0074] Specifically, in order to accurately obtain the temperature strain signal, it is necessary to prepare a high-quality sensitive grid pattern on the surface of the sensing layer 4 through ultrashort pulse laser processing. By using the finite element method to simulate the temperature gradient distribution law on the raceway surface under different loads and speeds, the key thermally sensitive areas and space-time resolution requirements are determined, and the optimal measuring point position is determined.

[0075] Reference Figure 2 and Figure 3 In response to the temperature measurement requirements of the limited space of the bearing raceway surface, a multi-fold S-shaped sensitive grid structure 6 is proposed, in which the line segment filling area is a laser-etched area, which adapts to the small size constraint while ensuring high sensitivity, and the effective longitudinal grid length is greater than 1mm.

[0076] The Pt film layer (the area filled with lines in the image above) is precisely removed from the composite film layer on the bearing raceway to form a sensitive grid pattern. Dynamic focus compensation is achieved through a five-axis machine tool combined with a 3D galvanometer to avoid distortion of the processed pattern caused by defocus and non-linear machining.

[0077] In terms of laser parameter selection, a green picosecond laser (535nm / 500fs) was used to suppress the heat diffusion distance. The initial energy density was determined through a single-pulse ablation threshold experiment, and the actual processing energy was calibrated in combination with the film absorption coefficient and the spot overlap rate. Multiple scans were performed at low energy density and high repetition frequency to achieve clean peeling of the Pt film and ensure edge quality. A white light interferometer was used to detect film residues and groove morphology for feedback optimization, ultimately obtaining a sensitive gate structure with a line width accuracy of ±5μm and a relative position deviation of less than 10μm.

[0078] S6. Preparation of wear-resistant protective layer: depositing a wear-resistant material on the sensing layer 4 obtained in S5 by plasma-assisted vapor deposition to form a wear-resistant protective layer 5, thereby obtaining a temperature sensor integrated with the bearing.

[0079] Specifically, a low-stress gradient DLC film layer is prepared as the wear-resistant protective layer 5 by plasma-assisted vapor deposition with a substrate bias of 700 V, an acetylene flow rate of 280 sccm, and a hydrogen flow rate of 40 sccm. The deposition time is 120 minutes, the film thickness is 2 μm, and the protective layer 5 covers other areas of the temperature sensor except the welding pad, ensuring the long-term operation stability of the sensitive gate in the high-stress and high-temperature environment of the bearing contact area.

[0080] 2. Application Examples

[0081] Reference Figure 1 and Figure 4 , an application of a temperature sensor integrated with a bearing in measuring the temperature of the bearing outer ring raceway area, the specific steps are as follows: lead out the pin 63 electrode of the thin film temperature sensor through the high-temperature wire 7, connect it to the strain acquisition system to realize signal acquisition.

[0082] In the actual test signal, the resistance change of the Pt thin film resistor gate is affected by the combined effects of temperature and pressure. The strain caused by pressure will cause the temperature reading to drift. Therefore, the temperature needs to be separated from the coupled signal. The schematic diagram of the sensitive gate layout is shown in the figure. Figure 4 shown.

[0083] Assume that the change in the two gate resistances satisfies:

[0084]

[0085] Among them S T is the temperature sensitivity coefficient, S F is the stress sensitivity coefficient.

[0086] The temperature variation coefficient S of the sensitive grids 61 and 62 can be confirmed by the constant temperature box temperature calibration experiment. T1 、S T2, the stress coefficient S of sensitive grids 1 and 2 was confirmed by calibration experiment using standard pressure loading source under constant temperature conditions. F1 、S F2 The necessary conditions for the equation to have an analytical solution are that the strain transfer functions of the two sensitive gates are linearly independent and the sensing metal layer of the sensitive gates is made of the same material. To achieve this, the geometric shape of the sensitive gates must be changed.

[0087] In practical applications, the sensitive grids 61 and 62 are located in the symmetrical area of ​​the bearing load zone, so it is assumed that the temperature change and pressure change they are subjected to are approximately equal. Solving equation (1) together yields the temperature decoupling equation:

[0088]

[0089] Finally, the system is used to realize accurate dynamic monitoring of the bearing raceway area temperature.

[0090] In summary, the temperature sensor provided by the present invention enhances the bonding force between the insulating layer 3 and the bearing base 1 by adding a transition seed layer 2 between the bearing base 1 and the insulating layer 3, thereby reducing the probability of sensor failure due to the large difference in thermal expansion coefficient between the insulating layer 3 and the bearing base 1, and improving the use effect of the sensor.

[0091] The preparation method of the temperature sensor provided by this method adopts magnetron sputtering combined with plasma enhanced chemical vapor deposition coating process to prepare and deposit transition seed layer 2, insulation layer 3, sensing layer 4, and wear-resistant protective layer 5 on the entire surface of the bearing raceway from bottom to top. By integrating the temperature sensor on the raceway surface, it is closer to the highest temperature area, thereby realizing in-situ integration of the bearing temperature sensor, realizing in-situ real-time temperature perception, and improving the accuracy and stability of detection. The multi-layer composite film meets the requirements of wear resistance, high temperature resistance, wide temperature range and high response speed, so as to adapt to the raceway environment. This solution starts from the source of the fault, forms intelligent diagnosis technology and criteria based on the temperature of the bearing contact area, enriches the bearing fault detection method, forms positive guidance for bearing design, and also provides a new idea for aviation high-speed and light-load bearing fault diagnosis technology.

Claims

1. A temperature sensor integrated with a bearing, characterized in that: It comprises a multi-layer composite thin film resistor grid structure, wherein the composite thin film comprises a bearing base, a transition seed layer, an insulating layer, a sensing layer and a wear-resistant protective layer from the inside to the outside.

2. The temperature sensor according to claim 1, wherein: The transition seed layer is made of nickel-chromium-aluminum-yttrium (NiCrAlY) alloy material, and the film thickness is 400-500nm.

3. The temperature sensor according to claim 1, wherein: The insulating layer is formed by combining two layers of heterogeneous materials, thermally grown oxide (TGO) and aluminum oxide (Al2O3), with a film thickness of 3000-3200nm.

4. The temperature sensor according to claim 1, wherein: The sensing layer is made of platinum (Pt) material, the film thickness is 450-500nm, and the surface of the sensing layer has a sensitive gate structure.

5. The temperature sensor according to claim 4, characterized in that: The sensitive gate structure is a multi-fold S-shaped structure, and the effective longitudinal gate length of the sensitive gate structure is greater than 1 mm.

6. The temperature sensor according to claim 1, wherein: The wear-resistant protective layer is made of diamond-like carbon (DLC) film material.

7. A method for preparing a temperature sensor integrated with a bearing according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Sample polishing and cleaning: The bearing raceway working surface is ground and polished, and the treated bearing is ultrasonically cleaned and plasma cleaned to obtain a clean bearing base; S2. Preparation of transition seed layer: a transition seed layer is prepared on the bearing substrate of S1 by DC magnetron sputtering; S3, preparation of insulating layer: aluminum precipitation and thermal oxidation are performed on the transition seed layer deposited in S2 to obtain a thermally grown oxide (TGO) layer, and then an insulating film material is deposited on the TGO layer by radio frequency magnetron sputtering to obtain an insulating layer; S4, preparation of sensing layer: using DC magnetron sputtering to deposit the sensing material on the insulating layer obtained in S3 to obtain the sensing layer; S5. Sensitive gate preparation: preparing a sensitive gate pattern on the surface of the sensing layer obtained in S4 by ultrashort pulse laser processing; S6. Preparation of wear-resistant protective layer: depositing a wear-resistant material on the sensing layer obtained in S5 by plasma-assisted vapor deposition to form a wear-resistant protective layer, thereby obtaining a temperature sensor integrated with the bearing.

8. The preparation method according to claim 7, characterized in that: S1. Sample polishing and cleaning: Before leaving the factory, the bearing raceway surface is subjected to rough polishing, manual rough polishing, semi-finishing polishing and fine polishing in sequence. After a series of grinding and polishing, the processed surface should be polished into a mirror finish, and the average surface roughness Ra of the working surface should be better than 40nm (for bearings with a nominal diameter of less than 80mm). Then, the treated bearing is immersed in petroleum ether and anhydrous ethanol in sequence for 20 minutes of high-power ultrasonic cleaning, and blown dry with dry nitrogen. Use a disposable dust-free cloth to wipe the sample and target material. Wear dust-free gloves to install the target material and sample in the vacuum coating equipment, turn on the mechanical pump and molecular pump, and adjust the chamber pressure to 4x10 -4 Pa, then slowly introduce argon gas and turn on the ion source for plasma cleaning to completely remove the organic pollutants on the sample surface and obtain a clean bearing substrate.

9. The preparation method according to claim 7, characterized in that: S5. Preparation of sensitive gates: Part of the sensing layer is accurately removed from the composite film layer on the bearing raceway surface to form a sensitive gate pattern. Dynamic focus compensation is achieved through a five-axis linkage machine tool combined with a 3D galvanometer. Green picosecond laser (535nm / 500fs) is selected as the laser parameter. The initial energy density is determined through a single-pulse ablation threshold experiment. The actual processing energy is calibrated based on the film absorption coefficient and the spot overlap rate. Multiple scans are performed at low energy density and high repetition frequency to achieve clean peeling of the Pt film and ensure edge quality. The film residue and groove morphology are detected with a white light interferometer for feedback optimization, and finally a sensitive gate structure with a line width accuracy of ±5μm and a relative position deviation of less than 10μm is obtained.

10. Use of a temperature sensor integrated with a bearing according to any one of claims 1 to 6 in measuring the temperature of a bearing outer ring raceway area.

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