Grease lubrication friction electricity passive wireless rotating speed sensor for bearing slip monitoring

Abstract

The utility model discloses a grease lubrication friction electricity passive wireless rotating speed sensor for bearing slip monitoring, which comprises two bearing seat cover bodies used for mounting a bearing body, a friction nanometer generator, a signal processing module and a power supply management module, and is characterized in that the friction nanometer generator consists of a rotor unit and a stator unit; the inner ring surface of the bearing body is fixedly connected with a rotating shaft, and the rotating shaft can sequentially drive the bearing retainer and the rotor unit to rotate so as to output electric energy. According to the utility model, the rotor unit and the stator unit are arranged, an interface grease lubrication strategy is utilized, the energy supply level and durability of the friction nanometer generator are improved, and wireless real-time monitoring of the slip state of the bearing body in a compact space in a transmission system can be realized without the help of an external power supply; the working reliability and the intelligent operation and maintenance level of mechanical equipment are improved, and high-performance operation of high-end equipment is further guaranteed.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of self-power supply and self-sensing of intelligent bearings, in particular to a grease-lubricated triboelectric passive wireless rotating speed sensor for bearing slip monitoring. BACKGROUND

[0002] Rolling bearings are one of the most critical basic components of rotating mechanical systems, and effective state monitoring of the bearings is of great significance to the safe and stable operation of mechanical equipment. Slip, that is, the unintended relative movement between the inner and outer rings and the rolling elements of the bearing due to excessive lubrication, insufficient load or improper assembly, etc., may cause local overheating, surface damage and even rapid failure of the entire bearing system, and is one of the failure modes of rolling bearings during operation, especially in the high-speed and light-load working conditions in the fields of aerospace, etc. Once slip occurs, it will pose a great threat to the stable operation of the bearing. By monitoring the bearing slip in real time, potential fault points can be found in time, and preventive measures can be taken to avoid equipment downtime, production line interruption and even more serious safety accidents caused by bearing failure.

[0003] According to the search, the Chinese patent with the publication number CN117572015A also discloses an electromagnetic rotating speed sensor, which is based on the principle of electromagnetic induction and is powered by an internal power supply. The data can be wirelessly transmitted through a signal transmission circuit to realize the purpose of real-time acquisition of the rotating speed of the measured parts such as wheels. However, compared with the traditional electromagnetic generator, the triboelectric nanogenerator has the advantages of wide material source, simple manufacturing process, compact structure and high energy density. The triboelectric rotating speed sensor of the triboelectric nanogenerator has a wide application in the field of bearing slip monitoring. However, the traditional triboelectric sensor still has the following problems in monitoring bearing slip: (1) The continuous dry friction between the friction pairs of the sensor will cause the reduction of the durability and stability of the TENG, directly affecting the signal-to-noise ratio and service life of the sensor; (2) The traditional triboelectric sensor has built-in signal processing circuit and other corresponding functional modules, which need to be powered separately. Usually, a button cell or other power supply device is built-in. However, the traditional battery power supply has the disadvantages of limited service life and large size which is not conducive to integration. The external power supply needs to transmit the signal from the rotating parts such as bearings to the upper computer through wires, which will affect the reliability of the bearing system. SUMMARY

[0004] The purpose of the utility model is to provide a grease-lubricated triboelectric passive wireless rotating speed sensor for bearing slip monitoring to solve the problems raised in the background art.

[0005] The application embodiment adopts the following technical scheme:

[0006] The application discloses a grease lubrication frictional electricity passive wireless rotating speed sensor for bearing slip monitoring.

[0007] Further, the rotor unit comprises a connecting piece, a boss is arranged on the side of the connecting piece close to the bearing, and a rotor body is arranged on the side of the connecting piece away from the bearing; the rotor unit is clamped with the bearing retainer through the boss, and the two realize interference fit.

[0008] Further, the stator unit comprises a stator end cover, and a stator body is fixedly connected in the stator end cover through high-temperature glue; the stator body is a metal electrode in a rotating array staggered distribution.

[0009] Further, the rotor body and the stator body are of the same structure and both comprise an inner ring electrode and an outer ring electrode; the inner ring electrode serves as a signal source of the sensor itself, and the outer ring electrode serves as an energy source for signal processing of the sensor.

[0010] Further, a lubricating grease with low dielectric constant and low consistency is added between the rotor body and the polymer film.

[0011] Further, a sealing end cover is fixedly connected to the outer ring of the bearing body, the stator end cover is fixedly connected with the sealing end cover through screws, and a rubber gasket is arranged between the sealing end cover and the stator end cover.

[0012] Further, a sealing groove is processed on the inner circumferential surface of the sealing end cover, and a plurality of sealing grooves form a labyrinth sealing structure; the radius of the sealing groove is 0.8 mm, and the single-side gap of the connecting piece is 0.5 mm.

[0013] Further, the signal processing module is integrated on the back of the stator body; and the power management module is integrated on the back of the stator body.

[0014] Further, the method for detecting bearing slip by using the sensor comprises the following steps.

[0015] S1, a frictional electricity signal generated by mutual friction of the stator unit and the rotor unit under the action of grease lubrication;

[0016] S2, the signal processing module calculates the actual rotating speed of the retainer according to the characteristic frequency of the extracted frictional electricity signal; the calculation is as follows:

[0017] n c =60f sig / N

[0018] Wherein, n c is the actual rotating speed of the retainer, and fsig is the frequency of the triboelectric signal, N is the number of groups of the staggered distribution metal electrodes of the triboelectric nanogenerator.

[0019] S3, the signal processing module calculates the theoretical cage rotating speed according to the inner ring rotating speed and the cage rotating speed calculation formula of the rolling bearing:

[0020]

[0021] wherein n0 is the theoretical cage rotating speed, n i is the inner ring rotating speed of the bearing, D w is the ball diameter, D pw is the pitch diameter of the bearing, and alpha b is the contact angle of the bearing.

[0022] S4, the slip rate of the cage is calculated according to the actual cage rotating speed and the theoretical cage rotating speed by using the single-chip microcomputer minimum system in the signal processing module:

[0023]

[0024] wherein n0 and n c are the theoretical rotating speed and the actual rotating speed of the cage under the pure rolling condition respectively.

[0025] The above at least one technical scheme adopted by the embodiments of the present application can achieve the following beneficial effects:

[0026] 1. By setting the rotor unit and the stator unit, and using the rotating shaft to drive the rotor unit to rotate, the wireless real-time monitoring of the slip state of the bearing body in the compact space inside the transmission system can be realized without the aid of an external power source, the working reliability and the intelligent operation and maintenance level of the mechanical equipment are improved, and the high-performance operation of high-end equipment is further ensured.

[0027] 2. By adding the low-dielectric-constant and low-consistency lubricating grease between the friction interfaces of the stator unit and the rotor unit, the wear of the triboelectric nanogenerator can be reduced, the output charge of the triboelectric nanogenerator can be further improved, and the stability of the cage slip state monitoring under passive conditions can be ensured.

[0028] 3、Since the signal processing module needs external power supply, two friction nanometer generator units are designed, one as a sensor and one as an energy source. BRIEF DESCRIPTION OF DRAWINGS

[0029] The drawings described herein are used to provide further understanding of the present application, and form a part of the present application.

[0030] Figure 1 It is a schematic diagram of the three-dimensional structure of the present application;

[0031] Figure 2 It is an exploded structure schematic diagram of the present application;

[0032] Figure 3 It is an exploded structure schematic diagram of the present application

[0033] Figure 4 It is a sectional view of the present application;

[0034] Figure 5 It is an enlarged view of the sectional view;

[0035] Figure 6 It is an electrode front view;

[0036] Figure 7 It is a signal processing flow chart of the triboelectric passive wireless rotational speed sensor;

[0037] Figure 8 It is a working principle diagram of the grease lubrication triboelectric passive wireless rotational speed sensor according to the embodiment of the present application;

[0038] Figure 9 It is a signal time domain waveform diagram of the triboelectric rotational speed sensor output voltage under the conditions of grease lubrication and dry friction;

[0039] Figure 10 It is a circuit principle diagram including a signal processing circuit and a power management circuit;

[0040] Figure 11The slip rate of the rolling bearing under different rotating speed load conditions is shown in the figure. DETAILED DESCRIPTION

[0041] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described below in connection with the embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0042] The technical solutions provided by the embodiments of the present application will be described in detail below in connection with the drawings.

[0043] Please refer to Figures 1-11 The utility model provides bearing slip monitoring's grease lubrication friction electricity passive wireless rotating speed sensor technical scheme:

[0044] A bearing slip monitoring's grease lubrication friction electricity passive wireless rotating speed sensor, including bearing seat cover body 2, bearing retainer 9, friction nanometer generator, signal processing module and power management module, wherein, bearing seat cover body 2 has two, is used to install bearing body 1, the inner ring of bearing body 1 is sleeved with rotating shaft 5, and the friction nanometer generator is composed of rotor unit 3 and stator unit 4.

[0045] Rotor unit 3 includes connecting piece 31, the side of connecting piece 31 close to the bearing is provided with boss 33, the side of connecting piece 31 away from the bearing is provided with rotor body 32, rotor unit 3 is clamped with bearing retainer 9 through boss 33, and the both realize interference fit, and locating boss 33 is processed on connecting piece 31 to ensure that rotor unit 3 is concentric with rotating shaft 5, can also realize the consistency of movement of rotor unit 3 and bearing retainer 9, and will not damage the structure of retainer 9, and rotating shaft 5 can drive retainer and rotor unit 3 to rotate in turn to output electric energy.Rotor body 32 is the metal electrode of rotating array distribution.

[0046] Stator unit 4 includes stator end cover 41, and stator end cover 41 is fixedly connected with stator body 42 in through high temperature glue, and stator body 42 is the metal electrode of rotating array staggered distribution.Stator body 42 is spin-coated with polymer film 6.The metal electrode of the end surface of rotor unit 3 is contacted and rubbed with polytetrafluoroethylene to generate electric signal, so that the potential difference is induced between the staggered metal electrodes of the end surface of stator unit.

[0047] Specifically, by setting the rotor unit 3 and the stator unit 4 and driving the rotor unit 3 to rotate by the bearing retainer, wireless real-time monitoring of the slipping state of the bearing body 1 in the compact space inside the transmission system can be realized without the aid of an external power supply, the working reliability of the mechanical equipment and the intelligent operation and maintenance level are improved, and the high-performance operation of high-end equipment is further ensured.

[0048] As shown in Figure 6 The rotor body 32 and the stator body 42 are structurally identical, both including an inner ring electrode and an outer ring electrode, the inner ring electrode serving as a signal source of the sensor itself, and the outer ring electrode serving as an energy source for signal processing of the sensor.

[0049] A low-dielectric-constant and low-consistency lubricating grease is added between the rotor body 32 and the polymer film 6. The lubricating grease can reduce the wear of the friction nanogenerator while further improving the output charge of the friction nanogenerator, ensuring the stability of the retainer slipping state monitoring under passive conditions. Furthermore, the service life of the sensor and the power supply level are simultaneously improved under passive conditions. As shown in Figure 9 The open-circuit voltage time-domain waveforms of the sensor and the energy-providing friction nanogenerator under dry friction and grease lubrication conditions are tested, respectively. It can be seen that the electrical output of the friction nanogenerator can be increased by about 2 times after adding the low-dielectric-constant lubricating grease; the open-circuit voltage of the energy-providing friction nanogenerator is 2.5 times that of the sensor friction nanogenerator.

[0050] The outer ring of the bearing body 1 is fixedly connected with a sealing end cover 7, the stator end cover 41 is fixedly connected with the sealing end cover 7 through screws, a rubber gasket 8 is arranged between the sealing end cover 7 and the stator end cover 41, and the contact pressure between the stator unit 4 and the rotor unit 3 can be changed by adjusting the screw-in length.

[0051] A sealing groove 71 is processed on the inner circumferential surface of the sealing end cover 7, and a plurality of sealing grooves form a labyrinth sealing structure. The sealing structure is suitable for non-contact sealing in a high-speed environment, the radius of the sealing groove is 0.8 mm, and the single-sided gap of the connecting piece 31 is 0.5 mm. The selected bearing body 1 is a cylindrical roller bearing NUP2207 ECP, the outer diameter of the outer ring is 72 mm, and the outer diameter of the sealing end cover 7 is consistent with the outer diameter of the outer ring. The axial size of the entire sensor is 25.5 mm.

[0052] The signal processing module is integrated on the back of the stator body 42, and the signal processing module mainly consists of a waveform conversion circuit, a single-chip microcomputer minimum system and a 2.4G wireless transceiver module. The principle diagram of the waveform conversion circuit is as shown in Figure 10The main function is to convert the triboelectric signal into a square wave signal, and the specific signal processing process is: the hysteresis comparator in the waveform conversion circuit is used to convert the triboelectric signal into a square wave signal; then a series of discrete time sequences corresponding to the pulse falling edge are recorded by using a single-chip microcomputer, the actual rotating speed of the retainer is calculated according to the characteristic frequency of the discrete time sequence, the slip rate of the retainer is calculated through the bearing rotating speed, and finally the slip rate is sent to the upper computer by using a wireless transmission module. The function of the minimum system of the single-chip microcomputer is mainly to calculate the instantaneous angular velocity of the square wave signal; considering that most of the bearing-rotor system is a rotating part, if the angular velocity signal is transmitted through a wired connection, it is easy to cause safety hazards in the system, therefore, the instantaneous angular velocity calculated by the microprocessor is transmitted through a 2.4G wireless module.

[0053] Specifically, the power management module is integrated on the back of the stator body 42, as shown in Figure 7 The power management module is designed based on voltage division comparison, and its function is to temporarily store the electric energy generated by the triboelectric nanogenerator in the energy storage capacitor, set the high and low threshold voltages of the on and off of the MOS tube through the voltage division circuit and the hysteresis comparison, when the voltage across the energy storage capacitor is less than the high threshold voltage, the comparator outputs a high level, the MOS tube is cut off, and the load is not powered. When the voltage across the energy storage capacitor is greater than the high threshold voltage, the comparator outputs a low level, the MOS tube is turned on, and the energy storage capacitor supplies power to the rear-end load. After the load completes a work, the energy of the energy storage capacitor is consumed, and when the voltage across the energy storage capacitor is lower than the low threshold voltage, the comparator outputs a high level again, the MOS tube is cut off, and the load is powered off. After several cycles, the load is powered on when the MOS tube is turned on, and is powered off when the MOS tube is cut off, the energy of the energy storage capacitor is consumed to complete a wireless transmission, and then the sensor can continuously and stably monitor the bearing retainer slip without any external power supply.

[0054] The power generation principle of the triboelectric rotating speed sensor is to convert the rotating energy of the bearing into electric energy, as shown in Figure 8 When the bearing is running, the retainer drives the rotor unit to rotate, and relative motion occurs with the stator unit. The continuous friction between the metal electrodes of the rotor unit and the metal electrodes of the stator unit generates triboelectric charges, and then induces electric charges on the staggered distribution metal electrodes of the stator unit. With the continuous rotation of the bearing, the induced electric charges alternately move between the two electrodes, thereby generating a periodic alternating current.

[0055] In order to realize the above-mentioned embodiment, a method for detecting bearing slip by using a sensor is also provided in the embodiment, and specifically includes the following steps:

[0056] S1, the triboelectric signal generated by the mutual friction of the stator unit and the rotor unit under the action of grease lubrication;

[0057] S2, the signal processing module calculates the actual cage speed according to the characteristic frequency of the extracted triboelectric signal; the calculation is as follows:

[0058] n c =60f sig / N

[0059] Wherein, n c is the actual speed of the cage, f sig is the frequency of the triboelectric signal, and N is the number of groups of staggered metal electrodes of the triboelectric nanogenerator.

[0060] S3, the signal processing module calculates the theoretical speed of the cage according to the formula of the inner ring speed of the rolling bearing and the cage speed:

[0061]

[0062] Wherein n0 is the theoretical speed of the cage, n i is the inner ring speed of the bearing, D w is the ball diameter, D pw is the pitch diameter of the bearing, and a b is the contact angle of the bearing.

[0063] S4, using the single-chip microcomputer minimum system in the signal processing module, the slip rate of the cage is calculated according to the actual speed of the cage and the theoretical speed of the cage:

[0064]

[0065] Wherein, n0 and n c are the theoretical speed and the actual speed of the cage under the condition of pure rolling, respectively.

[0066] As Figure 11 is the overall slip rate of the bearing measured by the triboelectric sensor under different speed load conditions in this embodiment, it can be seen that the slip rate is higher under high speed light load condition.

[0067] The resistance value of the load resistor in the waveform conversion circuit is 20MΩ, and the value is based on the fact that the output voltage of the triboelectric nanogenerator remains basically unchanged when the load resistor is greater than 20MΩ.

[0068] The frequency of the analog signal is extracted by using the fixed angle timing method, that is, the rising edge of the square wave signal is counted within a specified time, and the signal frequency is obtained by counting the value and setting the time, and then the instantaneous speed of the cage is calculated.

[0069] A jumper is used to complete the 0Ω resistance, so that all wiring is realized on the top layer. Since the pin type component will produce a via to affect the bottom layer, all components are used in the form of a patch.

[0070] It should also be noted that the terms "comprising," "including," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises a... " does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0071] The above description is merely illustrative of the application, and not restrictive. Various modifications and changes can become apparent to those skilled in the art. Incorporating any modification, equivalent substitution, improvement, etc. within the spirit and principle of the application, shall be included in the scope of the claims of the application.

Claims

1. A grease-lubricated triboelectric passive wireless speed sensor for monitoring bearing slippage, characterized in that, It includes a bearing housing cover (2), a bearing cage (9), a triboelectric nanogenerator, a signal processing module and a power management module. There are two bearing housing covers (2) for mounting the bearing body (1). The inner ring of the bearing body (1) is fitted with a rotating shaft (5). The triboelectric nanogenerator consists of a rotor unit (3) and a stator unit (4).

2. The sensor as described in claim 1, characterized in that, The rotor unit (3) includes a connector (31). A boss (33) is provided on the side of the connector (31) near the bearing, and a rotor body (32) is provided on the side of the connector (31) away from the bearing. The rotor unit (3) engages with the bearing cage (9) through the boss (33), and the two achieve an interference fit.

3. The sensor as described in claim 1, characterized in that, The stator unit (4) includes a stator end cover (41), and a stator body (42) is fixedly connected inside the stator end cover (41) by a high-temperature adhesive. The stator body (42) is a rotating array of staggered metal electrodes, and a polymer film (6) is spin-coated on the stator body (42).

4. The sensor as described in claim 3, characterized in that, The rotor body (32) and the stator body (42) have the same structure, both including inner and outer ring electrodes. The inner ring electrode serves as the signal source of the sensor itself, and the outer ring electrode serves as the energy source for sensor signal processing.

5. The sensor as described in claim 3, characterized in that, A low dielectric constant, low consistency grease is added between the rotor body (32) and the polymer film (6).

6. The sensor as described in claim 1, characterized in that, The outer ring of the bearing body (1) is fixedly connected to a sealing end cover (7), and the stator end cover (41) is fixedly connected to the sealing end cover (7) by screws. A rubber gasket (8) is provided between the sealing end cover (7) and the stator end cover (41).

7. The sensor as described in claim 1, characterized in that, The signal processing module is integrated on the back of the stator body (42); the power management module is integrated on the back of the stator body (42).

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