Double-rotor friction electric intelligent intermediate bearing and state monitoring method thereof

Abstract

The application discloses aero-engine double-rotor frictional electricity intelligent intermediate bearing and a state monitoring method thereof, and the method comprises the following steps: filtering high-frequency noise in a first alternating current signal generated by the intermediate bearing to obtain a second alternating current signal; calculating the actual rotating speed of a cage of the intermediate bearing according to the main frequency of the extracted second alternating current signal and the inner ring rotating frequency of the intermediate bearing; calculating the theoretical rotating speed of the cage of the intermediate bearing according to the rotating speed of the intermediate bearing with the inner and outer rings rotating simultaneously and a theoretical rotating speed calculation formula of the cage; and calculating the real-time slip rate of the intermediate bearing according to the actual rotating speed and the theoretical rotating speed of the cage of the intermediate bearing. The application can evaluate the health state of the intermediate bearing of the aero-engine, has a compact structure and can realize direct measurement.

Description

Technical Field

[0001] This invention relates to the field of intelligent bearing technology, and in particular to a dual-rotor triboelectric intelligent intermediate bearing for aero-engines and its condition monitoring method. Background Technology

[0002] Rolling bearings, as critical mechanical components, are widely used in modern industrial equipment such as motors, machine tools, and aerospace equipment. Their operating condition directly affects the performance, reliability, and lifespan of the system. Modern aero-engines, due to the high flexibility of their high- and low-pressure rotors, typically employ an intermediate bearing support scheme between the rotors to increase shaft rigidity. However, intermediate bearings are highly susceptible to damage due to their unique support position, distinctive operating mode, and complex operating conditions. Examples include roller-raceway slippage damage caused by light loads and high speeds, and cage instability due to aircraft maneuvers. Therefore, monitoring the health of intermediate bearings is a crucial measure to improve aircraft reliability and maintenance economy.

[0003] However, traditional methods for monitoring the health of aero-engine bearing support systems typically involve collecting vibration acceleration or surface acoustic emission signals from the casing. These indirect monitoring methods often fail to effectively identify the fault characteristics of intermediate bearings due to the long transmission path of the excitation force.

[0004] Therefore, there is an urgent need to design a compact, intelligent rolling bearing that can be directly measured and is applicable to intermediate bearings where the inner and outer rings rotate simultaneously, in order to meet the real-time service status assessment requirements of key components of aero-engines. Summary of the Invention

[0005] The present invention aims to at least partially solve one of the technical problems in the related art.

[0006] To address the issues of weak early fault detection capability and lack of direct monitoring methods in intermediate bearings of aero-engines, and to meet the high-performance service requirements of high-end equipment, this invention proposes a dual-rotor triboelectric intelligent intermediate bearing for aero-engines. This bearing can directly measure intermediate bearing slippage and cage speed fluctuations. A triboelectric bearing is a novel intelligent self-powered and self-sensing unit that integrates rolling bearings and triboelectric nanogenerators. It utilizes the coupling effect of triboelectric effect and electrostatic induction effect to convert the rotational kinetic energy of the rolling bearing into electrical energy.

[0007] Another objective of this invention is to propose a condition monitoring method for aero-engine dual-rotor triboelectric intelligent intermediate bearing.

[0008] To achieve the above objectives, this invention proposes a dual-rotor triboelectric intelligent intermediate bearing for aero-engines, comprising: a high-voltage rotor rotation unit, a low-voltage rotor rotation unit, and a cage unit.

[0009] The low-pressure rotor rotating unit includes a low-pressure shaft, a low-pressure shaft sleeve, an inner ring of an intermediate bearing, interdigitated electrodes, and an epoxy resin plate. The low-pressure shaft sleeve is interference-fitted with the low-pressure shaft. The inner ring of the intermediate bearing is interference-fitted with the outer cylindrical surface of the low-pressure shaft sleeve and is axially positioned. The interdigitated electrodes are disposed on the epoxy resin plate, and the epoxy resin plate is fixed to the right end face of the low-pressure shaft sleeve.

[0010] The high-pressure rotor rotating unit includes a high-pressure shaft and an intermediate bearing outer ring, wherein the intermediate bearing outer ring mates with the inner hole of the high-pressure shaft;

[0011] The cage unit includes an intermediate bearing cage, a dielectric material, and a bracket with a boss. The dielectric material is disposed on the surface of the boss on the bracket. The bracket mates with the side of the intermediate bearing cage and the outer ring of the intermediate bearing.

[0012] In addition, the aero-engine dual-rotor triboelectric intelligent intermediate bearing according to the above embodiments of the present invention may also have the following additional technical features:

[0013] Furthermore, in one embodiment of the present invention, the cage unit further includes intermediate bearing rolling elements. When at least one of the low-pressure shaft and the high-pressure shaft rotates, it drives the inner and outer rings of the intermediate bearing to rotate synchronously. The intermediate bearing rolling elements generate physical speed under the drive of the inner and outer ring raceways, and drive the intermediate bearing cage and the support with dielectric material to rotate together, so that the support and the interdigital electrodes generate relative rotation data, so that the induced charge between the interdigital electrodes flows to generate an alternating current signal.

[0014] Furthermore, in one embodiment of the present invention, the low-pressure rotor rotating unit further includes a lead slip ring, wherein the lead wires of the interdigitated electrodes rotate synchronously with the low-pressure shaft, and the electrical signals in the lead wires are led out through the lead slip ring.

[0015] Furthermore, in one embodiment of the present invention, the dielectric material is a distributed fan-shaped soft contact fluff dielectric material, and the support is a support with fan-shaped bosses.

[0016] Furthermore, in one embodiment of the present invention, the cage unit includes intermediate bearing rolling elements, an intermediate bearing cage, a distributed arrangement of fan-shaped soft contact fiber dielectric material, and an acrylic support.

[0017] Furthermore, in one embodiment of the present invention, the fan-shaped soft contact velvet dielectric material is adhered to the surface of the distributed bosses of the acrylic bracket by adhesive backing, and the acrylic bracket is fitted with the side and outer ring of the integral retainer by size matching and fixed by strong adhesive.

[0018] Furthermore, in one embodiment of the present invention, when the low-pressure shaft or high-pressure shaft of the aero-engine rotates, or both rotate simultaneously, it drives the inner and outer rings of the intermediate bearing to rotate synchronously. The rolling elements of the intermediate bearing rotate and revolve under the drive of the inner and outer ring raceways, and drive the cage and the support with the dielectric material of distributed soft contact fluff to rotate together. The dielectric material and the comb-shaped interdigital electrodes experience relative friction, generating corresponding charges between the interdigital electrodes. As the support and the interdigital electrodes rotate relative to each other, the induced charge flow between the two interdigital electrodes generates an alternating current signal.

[0019] Furthermore, in one embodiment of the present invention, the mutual friction between the dielectric material and the interdigital electrodes can improve the output of triboelectricity without damaging the electrode surface, thus avoiding the disadvantages of non-contact and sliding friction triboelectric generators.

[0020] Furthermore, in one embodiment of the present invention, the interdigitated electrode rotates synchronously with the inner ring of the intermediate bearing, which solves the problem that it is difficult to install the power generation component in the intermediate bearing because there are no fixed parts in the intermediate bearing.

[0021] Furthermore, in one embodiment of the present invention, the stationary component of the lead slip ring is connected to the non-rotating component of the aero-engine, thus solving the problem of extracting triboelectric signals.

[0022] Furthermore, in one embodiment of the present invention, the dielectric material is able to withstand the high rotational speed of the triboelectric bearing without rapid wear and deterioration.

[0023] Furthermore, in one embodiment of the present invention, the axial space of the triboelectric assembly can be controlled within 2-3 mm.

[0024] Furthermore, in one embodiment of the present invention, the length and material of the soft contact fluff material of the dielectric material can adjust the output of the intelligent triboelectric bearing.

[0025] Furthermore, in one embodiment of the present invention, the number of comb teeth of the interdigital electrode should be equal to the number of dielectric materials of the soft contact fibers.

[0026] Furthermore, in one embodiment of the present invention, the dielectric material is swept and rubbed against the interdigital electrodes. When the intermediate bearing is working normally, the potential difference drives the induced charge to flow back and forth between the two interdigital electrodes to generate an AC signal, and the frequency of the AC signal changes with the speed difference between the intermediate bearing cage and the inner ring of the intermediate bearing.

[0027] Furthermore, in one embodiment of the present invention, the speed difference between the intermediate bearing cage and the intermediate bearing inner ring is a characteristic parameter of this triboelectric bearing and an important indicator for monitoring the condition of the intermediate bearing.

[0028] It is understood that the triboelectric generator assembly of the present invention is a dielectric ring-soft contact material-interdigital electrode, wherein the dielectric ring is a bracket with bosses.

[0029] To achieve the above objectives, another aspect of the present invention proposes a condition monitoring method for aero-engine dual-rotor triboelectric intelligent intermediate bearing, comprising:

[0030] The high-frequency noise in the first AC signal generated by the intermediate bearing is filtered to obtain the second AC signal.

[0031] The actual rotational speed of the intermediate bearing cage is calculated based on the main frequency of the extracted second AC signal and the rotational frequency of the inner ring of the intermediate bearing.

[0032] The theoretical speed of the intermediate bearing cage is calculated based on the formula for calculating the speed of the intermediate bearing when the inner and outer rings rotate simultaneously and the theoretical speed of the cage.

[0033] The real-time slip rate of the intermediate bearing is calculated based on the actual and theoretical rotational speeds of the intermediate bearing cage.

[0034] The present invention relates to a dual-rotor triboelectric intelligent intermediate bearing for aero-engines and its condition monitoring method. The main structure consists of interdigitated electrodes that rotate together with the low-pressure rotor of the aero-engine. Triboelectric signals are generated by distributed fan-shaped soft-contact velvet dielectric material mounted on the side of the intermediate bearing cage sweeping across the interdigitated electrodes as the cage rotates. These triboelectric signals can assess the health status of the aero-engine intermediate bearing; the structure is compact and enables direct measurement.

[0035] The beneficial effects of this invention are as follows:

[0036] (1) This invention proposes a triboelectric intelligent intermediate bearing. The soft contact material can improve the output of the triboelectric generator without damaging the electrode surface, and can realize high-speed intermediate bearing condition monitoring. The electrode structure that rotates together with the inner ring of the bearing makes the entire assembly free of non-rotating devices, making it suitable for the special bearing method of intermediate bearings.

[0037] (2) This invention proposes a triboelectric intelligent intermediate bearing. A rotating soft-contact dielectric material is irradiated by friction with rotating interdigital electrodes, generating an alternating current (AC) signal under electrostatic induction. The frequency of this AC signal changes synchronously with the rotational speed difference between the intermediate bearing cage and the inner ring of the intermediate bearing. Therefore, by analyzing the frequency of the AC signal generated by this triboelectric bearing and obtaining the rotational speed of the low-pressure rotor of the aero-engine, the slippage rate of the intermediate bearing can be obtained through relevant calculations. Statistical analysis of the sinusoidal period of the AC signal and the instantaneous rotational speed of the low-pressure rotor can be performed to evaluate the rotational stability of the intermediate bearing cage. This triboelectric bearing enables real-time direct measurement of the intermediate bearing and has advantages such as self-drive, self-sensing, shortened signal transmission path, and long service life.

[0038] (3) For bearings with similar operating modes to those in aero-engine intermediate bearings, similar structures can be adopted for condition monitoring, and multiple triboelectric intelligent intermediate bearings can be combined simultaneously during use to further increase the output power.

[0039] (4) Real-time health monitoring of aero-engine bearings improves the operation and maintenance level of aero-engine equipment and ensures the high-performance operation of aero-engine equipment.

[0040] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0041] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0042] Figure 1 This is a schematic diagram of the structure of the aero-engine dual-rotor triboelectric intelligent intermediate bearing according to an embodiment of the present invention;

[0043] Figure 2 This is an overall assembly drawing of the aero-engine dual-rotor triboelectric intelligent intermediate bearing structure according to an embodiment of the present invention;

[0044] Figure 3 This is a schematic diagram of the power generation principle of the dual-rotor triboelectric intelligent intermediate bearing for aero-engines according to an embodiment of the present invention;

[0045] Figure 4 This is a flowchart of a condition monitoring method for a dual-rotor triboelectric intelligent intermediate bearing for aero-engines according to an embodiment of the present invention;

[0046] Figure 5 This is a time-domain waveform diagram of the output current signal of the triboelectric intelligent intermediate bearing under seven speed conditions when the inner and outer rings rotate in opposite directions according to an embodiment of the present invention.

[0047] Figure 6 This is a schematic diagram of the output current spectrum and slippage rate when the theoretical rotational speed of the cage is 500 rpm, according to an embodiment of the present invention.

[0048] Figure 7 This is a schematic diagram of the cage transient rotational speed information according to an embodiment of the present invention;

[0049] Figure 8 This is a schematic diagram of the normal distribution function of the instantaneous rotational speed data of the cage according to an embodiment of the present invention.

[0050] Explanation of reference numerals in the attached drawings: 1. Low-pressure shaft; 2. Low-pressure shaft sleeve; 3. High-pressure shaft; 4. Intermediate bearing outer ring; 5. Intermediate bearing rolling element; 6. Intermediate bearing inner ring; 7. Intermediate bearing cage; 8. Support; 9. Dielectric material; 10. Interdigitated electrode; 11. Epoxy resin board; 12. Lead wire slip ring. Detailed Implementation

[0051] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0052] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0053] The following description, with reference to the accompanying drawings, illustrates an embodiment of the present invention of a dual-rotor triboelectric intelligent intermediate bearing for aero-engines and its condition monitoring method.

[0054] Figure 1 This is a schematic diagram of the structure of the dual-rotor triboelectric intelligent intermediate bearing for aero-engines according to an embodiment of the present invention.

[0055] like Figure 1 As shown, this aero-engine dual-rotor triboelectric intelligent intermediate bearing includes a high-pressure rotor rotation unit, a low-pressure rotor rotation unit, and a cage unit.

[0056] The low-pressure rotor rotating unit includes a low-pressure shaft 1, a low-pressure shaft sleeve 2, an inner ring 6 of an intermediate bearing, interdigitated electrodes 10, and an epoxy resin plate 11. The low-pressure shaft sleeve 2 is interference-fitted with the low-pressure shaft 1. The inner ring 6 of the intermediate bearing is interference-fitted with the outer cylindrical surface of the low-pressure shaft sleeve 2 and is axially positioned. The interdigitated electrodes 10 are disposed on the epoxy resin plate 11, and the epoxy resin plate 11 is fixed to the right end face of the low-pressure shaft sleeve 2.

[0057] The high-pressure rotor rotating unit includes a high-pressure shaft 3 and an intermediate bearing outer ring 4, which is fitted with the inner hole of the high-pressure shaft 3.

[0058] The cage unit includes an intermediate bearing cage 7, a dielectric material 9, and a bracket 8 with a boss. The dielectric material 9 is disposed on the surface of the boss of the bracket 8. The bracket 8 mates with the side of the intermediate bearing cage 7 and the outer ring 4 of the intermediate bearing.

[0059] As some embodiments of the present invention, such as Figure 2As shown, the triboelectric intelligent intermediate bearing includes a high-voltage rotor rotating unit, a low-voltage rotor rotating unit, and a cage unit. The high-voltage rotor rotating unit includes a high-voltage shaft 3 and an intermediate bearing outer ring 4. The low-voltage rotor rotating unit includes a low-voltage shaft 1, a low-voltage shaft sleeve 2, an intermediate bearing inner ring 6, a 0.1mm thick copper interdigitated electrode 10, an epoxy resin plate 11, and a lead wire slip ring 12. The cage unit includes intermediate bearing rolling elements 5, an intermediate bearing cage 7, a dielectric material 9 with distributed fan-shaped soft contact fibers, and a bracket 8 with fan-shaped bosses. The low-voltage shaft sleeve 2 is interference-fitted with the low-voltage shaft 1, and the intermediate bearing inner ring 6 is interference-fitted with the outer cylindrical surface of the low-voltage shaft sleeve 2 and axially positioned by the shaft shoulder. The interdigitated electrode 10 is printed on the epoxy resin plate 11, which is fixed to the right end face of the low-voltage shaft sleeve 2 by screws. The lead wires of the interdigitated electrode 10 rotate synchronously with the low-voltage rotor rotating unit, and the electrical signals in the wires are led out through the lead wire slip ring 12. The dielectric material 9 of the fan-shaped soft contact fluff is attached to the boss surface of the bracket 8 with the fan-shaped boss by adhesive backing. The bracket 8 fits the side and outer ring of the intermediate bearing cage 7 by size matching and is fixed by strong adhesive.

[0060] In some embodiments of the present invention, the epoxy resin plate 11 has a thickness of 1.6 mm, and the thickness (pile length) of the dielectric material 9 of the fan-shaped soft contact pile is 1-2 mm. The gap between the dielectric material 9 of the fan-shaped soft contact pile and the interdigital electrode 10 can be adjusted by the pile length or by the thin shim between the epoxy resin plate 11 and the low-pressure shaft sleeve 2. The outer ring of the lead slip ring 12 is connected to the non-rotating parts of the aero-engine.

[0061] As some embodiments of the present invention, such as Figure 2 As shown, the selected bearing model is NU1005 detachable outer ring roller bearing. The thickness of the intermediate bearing cage 7 is 2.59mm and the width is 9.2mm. The inner diameter of the intermediate bearing outer ring 4 is 41.4mm. The maximum outer diameter of the bracket 8 is 40mm. The difference between the inner diameter of the intermediate bearing outer ring 4 and the maximum outer diameter of the bracket 8 is 1.4mm, which is slightly greater than the radial whirl displacement of the cage by 1.1mm, to prevent the bracket 8 from colliding with the bearing outer ring when the intermediate bearing cage 7 whirls.

[0062] Furthermore, the power generation principle of the aero-engine dual-rotor triboelectric intelligent intermediate bearing based on an integral cage is to convert the rotational mechanical energy of the cage into electrical energy, such as... Figure 3The diagram shows the power generation principle of this triboelectric intelligent intermediate bearing during one operating cycle. Due to the triboelectric charging and electrostatic induction of the soft contact fibers and metal electrodes, relative friction occurs between the dielectric material 9 of the distributed soft contact fibers and the comb-shaped interdigital electrodes 10, generating corresponding charges between the interdigital electrodes. The dielectric material 9 rotates with the cage, but its rotational speed is not synchronized with that of the rotating interdigital electrodes 10. When these two components move relative to each other, the induced charges move alternately between the two electrodes, generating a periodic alternating current in the external load connected to the interdigital electrodes. The sinusoidal period of the current is determined by the speed difference between the intermediate bearing cage and the inner ring of the intermediate bearing, and the number of teeth on the interdigital electrodes.

[0063] The intelligent intermediate bearing for dual-rotor triboelectric generators according to embodiments of the present invention improves the output of triboelectric power without damaging the electrode surface, avoids the disadvantages of non-contact and sliding friction triboelectric generators, enables real-time direct measurement of the intermediate bearing, and has advantages such as self-drive, self-sensing, shortened signal transmission path, and long service life.

[0064] To achieve the above embodiments, such as Figure 4 As shown, this embodiment also provides a condition monitoring method for aero-engine dual-rotor triboelectric intelligent intermediate bearing, including:

[0065] S1, filter the high-frequency noise in the first AC signal generated by the intermediate bearing to obtain the second AC signal;

[0066] S2, calculate the actual rotational speed of the intermediate bearing cage based on the main frequency of the extracted second AC signal and the rotational frequency of the inner ring of the intermediate bearing;

[0067] S3, Calculate the theoretical speed of the intermediate bearing cage based on the calculation formula of the intermediate bearing speed when the inner and outer rings rotate simultaneously and the theoretical speed of the cage;

[0068] S4. Calculate the real-time slip rate of the intermediate bearing based on the actual and theoretical rotational speeds of the intermediate bearing cage.

[0069] In some embodiments of the present invention, an electrostatic measurement device is used to collect the AC signal generated by the triboelectric intelligent intermediate bearing of the dual rotor of the aero-engine, and a signal processing module is used to filter out high-frequency noise in the original sinusoidal signal to obtain a stable AC voltage or current signal.

[0070] Specifically, electrostatic measurement equipment is used to collect the AC current and voltage signals generated by the triboelectric intelligent intermediate bearing of the dual rotor of the aero-engine. A signal processing module is then used to filter out high-frequency noise from the original sinusoidal signal to obtain a stable AC voltage or current signal; for example... Figure 5As shown, the 0.5s alternating current time-domain waveforms of the dual-rotor triboelectric intelligent intermediate bearing for aero-engines were tested under seven different operating conditions (inner ring speed: 400, 800, 1200, 1600, 2000, 2400, 2800 rpm; outer ring speed: 500, 1000, 1500, 2000, 2500, 3000, 3500 rpm) when the inner and outer rings rotated simultaneously. It can be seen that the amplitude of the alternating current generated by the dual-rotor triboelectric intelligent intermediate bearing for aero-engines does not show a clear pattern with the rotational speed, and the alternating period of the current decreases as the rotational speed increases.

[0071] In some embodiments of the present invention, a Fourier transform is performed on the alternating current or voltage signal to extract the main frequency of the sinusoidal signal, and the actual rotational speed of the intermediate bearing cage is calculated based on this frequency and the inner ring rotational frequency of the intermediate bearing.

[0072] Specifically, a Fourier transform is performed on the alternating current or voltage signal to extract the dominant frequency of the sinusoidal signal. Based on this frequency and the inner ring rotational frequency of the intermediate bearing, the actual rotational speed of the intermediate bearing cage is calculated. The calculation method for the actual cage rotational speed is as follows:

[0073]

[0074] n c =ω tebg -ω i

[0075] Where n c To maintain the orbital speed of the cage, ω teng ω is the rotational speed of the triboelectric component. i f is the rotational speed of the inner ring of the intermediate bearing. sig N is the characteristic frequency of the alternating current signal. e The number of comb teeth in the interdigital electrode.

[0076] In some embodiments of the present invention, the theoretical cage speed of the intermediate bearing under pure rolling conditions is calculated based on the intermediate bearing speed with the inner and outer rings rotating simultaneously and the corresponding theoretical cage speed calculation formula.

[0077] Specifically, the theoretical cage speed of the intermediate bearing under pure rolling conditions is calculated based on the calculation formula of the intermediate bearing speed when the inner and outer rings rotate simultaneously and the corresponding theoretical cage speed.

[0078]

[0079] Where ω c-th For the theoretical rotational speed of the intermediate bearing cage, ω o Where D is the outer ring speed of the intermediate bearing, and d is the diameter of the rolling element. m α is the pitch circle diameter of the intermediate bearing, and α0 is the contact angle.

[0080] In some embodiments of the present invention, the real-time slip rate of the intermediate bearing is calculated based on the actual rotational speed of the cage and the theoretical rotational speed of the cage.

[0081] Specifically, the cage slippage rate is calculated based on the actual cage rotational speed and the theoretical cage rotational speed:

[0082]

[0083] Where sk r The overall slippage rate of the intermediate bearing is represented by abs, where abs represents the absolute value. For example... Figure 6 This diagram illustrates the output current spectrum and slippage rate calculation of the triboelectric intelligent intermediate bearing in this example at a theoretical cage speed of 500 rpm. Because the inner ring rotates while the outer ring remains fixed, and the electrodes rotate together with the inner ring, the frequency of the output signal is higher than the theoretical speed of the bearing rolling elements when slippage occurs. This is the opposite of the signal characteristics exhibited by traditional triboelectric bearings when slippage occurs.

[0084] In some embodiments of the present invention, the time required for each alternating cycle of the processed time-domain AC signal is obtained, and the reciprocal of the time is compared with the instantaneous rotational speed of the inner ring to solve for the transient rotational speed of the intermediate bearing cage.

[0085] Specifically, based on the processed time-domain alternating current signal, the time required for each alternating cycle is obtained, and the reciprocal of the time is compared with the instantaneous speed of the inner race to solve for the transient speed of the intermediate bearing cage; for example... Figure 7 This refers to the instantaneous orbital speed of the cage within 5 seconds at a theoretical cage speed of 500 rpm.

[0086] In some embodiments of the present invention, the instantaneous rotational speeds of all cages over a period of time are statistically analyzed, and this set of instantaneous rotational speed data is fitted using a normal distribution function.

[0087] Specifically, the instantaneous rotational speeds of all cages over a period of time are statistically analyzed, and this set of instantaneous rotational speed data is fitted using a normal distribution function; for example... Figure 8 That is, in the above Figure 7 Distribution of instantaneous rotational speed data of the cage under operating conditions and fitting curve of normal distribution.

[0088] In some embodiments of the present invention, the parameter indices in the normal distribution function are used as the basis for evaluating cage stability.

[0089] Specifically, the parameters in the normal distribution function serve as the basis for evaluating cage stability. The normal distribution function is shown below:

[0090]

[0091] Where σ and μ are the standard deviation and expected value of the normal distribution, respectively, x is the deviation from the average rotational speed, and exp represents an exponential function with the natural constant e as the base. Here, the values ​​of σ and μ are used as indicators to evaluate cage stability. A larger σ indicates a more dispersed distribution of the instantaneous rotational speed of the cage, and thus poorer stability. A larger μ value away from 0 indicates a more asymmetrical distribution of the instantaneous rotational speed of the cage compared to the average rotational speed, and also poorer stability.

[0092] It is understood that the working principle of the condition monitoring method for the dual-rotor triboelectric intelligent intermediate bearing of aero-engines based on an integral cage described in this invention is as follows:

[0093] When the intermediate bearing is operating normally, the rotating soft-contact dielectric material 9 and the rotating interdigital electrode 10 are irradiated by friction, generating an alternating current signal under electrostatic induction. The frequency of this alternating current signal changes synchronously with the speed difference between the intermediate bearing cage 7 and the intermediate bearing inner ring 6. Therefore, by analyzing the frequency of the alternating current signal generated by this triboelectric bearing, obtaining the speed of the low-pressure rotor of the aero-engine, and performing relevant calculations, the slippage rate of the intermediate bearing can be obtained. By calculating and statistically analyzing the sinusoidal period of the alternating current signal and the instantaneous speed of the low-pressure rotor, the rotational stability of the intermediate bearing cage can be evaluated.

[0094] In summary, the embodiments of this invention utilize soft contact materials, which can improve the output of the triboelectric generator without damaging the electrode surface, and enable high-speed monitoring of the intermediate bearing condition. The electrode structure, which rotates with the inner ring of the bearing, eliminates the need for non-rotating devices in the entire assembly, making it suitable for this special bearing type of intermediate bearing.

[0095] The condition monitoring method for dual-rotor triboelectric intelligent intermediate bearings of aero-engines according to embodiments of the present invention can improve the operation and maintenance level of aero-engine equipment by real-time health monitoring of aero-engine bearings and ensure the high-performance operation of aero-engine equipment.

[0096] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0097] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

Claims

1. A dual-rotor triboelectric intelligent intermediate bearing for aero-engines, characterized in that, include: High-pressure rotor rotating unit, low-pressure rotor rotating unit, and cage unit. The low-pressure rotor rotating unit includes a low-pressure shaft, a low-pressure shaft sleeve, an inner ring of an intermediate bearing, interdigitated electrodes, and an epoxy resin plate. The low-pressure shaft sleeve is interference-fitted with the low-pressure shaft. The inner ring of the intermediate bearing is interference-fitted with the outer cylindrical surface of the low-pressure shaft sleeve and is axially positioned. The interdigitated electrodes are disposed on the epoxy resin plate, and the epoxy resin plate is fixed to the right end face of the low-pressure shaft sleeve. The high-pressure rotor rotating unit includes a high-pressure shaft and an intermediate bearing outer ring, wherein the intermediate bearing outer ring is fitted with the inner hole of the high-pressure shaft; The cage unit includes an intermediate bearing cage, a dielectric material, and a bracket with a boss. The dielectric material is disposed on the surface of the boss on the bracket. The bracket mates with the side of the intermediate bearing cage and the outer ring of the intermediate bearing.

2. The aero-engine dual-rotor triboelectric intelligent intermediate bearing according to claim 1, characterized in that, The cage unit further includes intermediate bearing rolling elements. When at least one of the low-pressure shaft and the high-pressure shaft rotates, it drives the inner and outer rings of the intermediate bearing to rotate synchronously. The intermediate bearing rolling elements generate physical speed under the drive of the inner and outer ring raceways, and drive the intermediate bearing cage and the support with dielectric material to rotate together, so that the support and the interdigital electrodes generate relative rotation data, so that the induced charge between the interdigital electrodes flows to generate an alternating current signal.

3. The aero-engine dual-rotor triboelectric intelligent intermediate bearing according to claim 1, characterized in that, The low-pressure rotor rotating unit also includes a lead slip ring. The lead wires of the interdigitated electrodes rotate synchronously with the low-pressure shaft and the electrical signals in the lead wires are led out through the lead slip ring.

4. The aero-engine dual-rotor triboelectric intelligent intermediate bearing according to claim 1, characterized in that, The dielectric material is a distributed fan-shaped soft contact fluff dielectric material, and the support is a support with fan-shaped protrusions.

5. A condition monitoring method for the dual-rotor triboelectric intelligent intermediate bearing of an aero-engine as described in any one of claims 1-4, characterized in that, include: The high-frequency noise in the first AC signal generated by the intermediate bearing is filtered to obtain the second AC signal. The actual rotational speed of the intermediate bearing cage is calculated based on the main frequency of the extracted second AC signal and the rotational frequency of the inner ring of the intermediate bearing. The theoretical speed of the intermediate bearing cage is calculated based on the formula for calculating the speed of the intermediate bearing when the inner and outer rings rotate simultaneously and the theoretical speed of the cage. The real-time slip rate of the intermediate bearing is calculated based on the actual and theoretical rotational speeds of the intermediate bearing cage.

6. The method according to claim 5, characterized in that, The method further includes: The transient speed of the intermediate bearing cage is calculated based on the time required for each alternating cycle of the second AC signal and the instantaneous speed of the inner ring of the intermediate bearing. The transient rotational speeds of all intermediate bearing cages within a preset time period are statistically analyzed to obtain transient rotational speed statistics. The parameter indexes are then obtained by fitting the transient rotational speed statistics with a normal distribution function. The stability of the intermediate bearing cage is evaluated based on the aforementioned parameters to obtain the stability evaluation results.

7. The method according to claim 6, characterized in that, The formula for calculating the actual rotational speed is as follows: n c =ω teng -oh i Where, n c To maintain the orbital speed of the cage, ω teng ω is the rotational speed of the triboelectric component. i f is the rotational speed of the inner ring of the intermediate bearing. sig N is the characteristic frequency of the alternating current signal. e The number of comb teeth in the interdigital electrode.

8. The method according to claim 7, characterized in that, The formula for calculating the theoretical rotational speed is as follows: Where, ω c-th For the theoretical rotational speed of the intermediate bearing cage, ω o Where D is the outer ring speed of the intermediate bearing, and d is the diameter of the rolling element. m α is the pitch circle diameter of the intermediate bearing, and α0 is the contact angle.

9. The method according to claim 8, characterized in that, The formula for calculating the real-time slip rate is as follows: Among them, sk r The overall slippage rate of the intermediate bearing is given by abs, which represents the absolute value.

10. The method according to claim 6, characterized in that, The expression for the normal distribution function is: Where σ and μ are the standard deviation and expected value of the normal distribution, respectively, x is the deviation from the average rotational speed, and exp represents an exponential function with the natural constant e as the base.

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