Bearing lubrication state monitoring method and device

Abstract

The invention provides a bearing lubrication state monitoring method and device, and the method comprises the steps: obtaining an original ultrasonic signal generated in the operation process of a bearing, and carrying out the amplification processing of the original ultrasonic signal, and obtaining an amplified ultrasonic signal; sub-signals of the amplified ultrasonic signals in the optimal monitoring frequency band are extracted, heterodyne frequency reduction processing is carried out on the sub-signals, and low-frequency monitoring signals are obtained; the energy intensity of the low-frequency monitoring signal is calculated, fusion calculation is conducted on the energy intensity and the optimal lubrication baseline intensity, and a fusion type decibel value is obtained; and the fusion type decibel value is compared with a preset decibel threshold value, and the bearing lubrication state is monitored. According to the method, a fusion type decibel index calculation mode and a comparison base line self-adaptive adjustment mode are provided, the complex obtaining process of the conventional sound pressure decibel quantity can be avoided, and meanwhile the difference between the current state and the optimal lubrication state of the bearing can be reflected more accurately, rapidly and visually; and the bearing lubrication state monitoring efficiency is improved while the reliability of a bearing lubrication state monitoring result is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of bearing operation status monitoring, and in particular to a bearing lubrication status monitoring method and device. Background Art

[0002] In the early stage of poor bearing lubrication, the increased friction between the internal structures of the bearing will lead to a significant increase in the signal energy in the ultrasonic frequency range. Therefore, the lubrication status monitoring technology based on ultrasonic signals has early warning capabilities. At the same time, the ultrasonic signal generated by the bearing covers a relatively large frequency band range. Considering the selection of acquisition device parameters and the improvement of analysis software processing efficiency, it is often necessary for monitoring personnel to know the key frequency bands to be concerned about in order to ensure the acquisition of the optimal indication signal. However, there is still a lack of guidance on the selection of frequency bands for bearing lubrication status monitoring based on ultrasound. If the selected narrowband signal contains weak effective information, the monitoring will be meaningless; if a wider frequency band is selected to ensure effective signal acquisition, the selected frequency signal will be subject to unnecessary interference, affecting the accuracy of the monitoring results. Therefore, the identification and selection of the optimal frequency band of ultrasound has important practical significance for the efficiency and reliability of monitoring results.

[0003] Ultrasonic bearing lubrication monitoring generally requires obtaining ultrasonic sound pressure decibels. This process requires complex frequency weighting, time weighting and other specific processing of the voltage signal output by the sensor, and the process is cumbersome and complicated. After obtaining the sound pressure decibels, it is compared with a fixed sound pressure decibel (baseline) under the optimal lubrication state to determine the lubrication state. However, the optimal lubrication state timing of different bearings in different situations is different, and there may be new optimal lubrication points during operation. If a fixed value is used for the comparison baseline, it is difficult to more accurately evaluate the gap between the current state and the optimal lubrication state of the bearing. In addition, the bearing state assessment is based on the comparison of the current measured decibel value with the fixed baseline decibel value. The evaluation mode of comparing two independent decibel values ​​makes monitoring too cumbersome. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a bearing lubrication status monitoring method and device, which are used to solve the technical problems existing in the bearing lubrication status monitoring in the prior art.

[0005] To achieve the above-mentioned object and other related objects, the present invention provides a bearing lubrication state monitoring method, comprising the following steps:

[0006] Acquire the original ultrasonic signal generated during the operation of the bearing;

[0007] amplifying the original ultrasonic signal to obtain an amplified ultrasonic signal;

[0008] Extracting a sub-signal of the amplified ultrasonic signal in the optimal monitoring frequency band and recording it as a first sub-signal; wherein the optimal monitoring frequency band is used to characterize the lubrication state of the bearing;

[0009] Performing heterodyne frequency reduction processing on the first branch signal to obtain a low-frequency monitoring signal;

[0010] Calculate the energy intensity of the low-frequency monitoring signal and fuse it with the optimal lubrication baseline intensity to obtain a fused decibel value; wherein the optimal lubrication baseline intensity is determined by the low-frequency monitoring signal and the rotational speed of the bearing;

[0011] The fused decibel value is compared with a preset decibel threshold, and the bearing lubrication status is monitored based on the comparison result.

[0012] In one embodiment of the present invention, the process of identifying the optimal monitoring frequency band includes:

[0013] Collect multiple ultrasonic signals generated by the bearing at different speeds when different grease injection amounts are applied;

[0014] Performing spectrum analysis on the multiple ultrasonic signals, and selecting multiple frequency bands whose energy density concentration is greater than a preset threshold in each ultrasonic signal segment;

[0015] Extracting sub-signals of each segment of the ultrasonic signal in the multiple frequency bands, recording them as second sub-signals, and calculating the energy intensity of the second sub-signals;

[0016] Based on the change in the amount of injected fat, a frequency band in which the energy intensity of the second component signal has a consistent change trend at different rotation speeds is selected as the optimal monitoring frequency band.

[0017] In one embodiment of the present invention, the process of determining the optimal lubrication baseline strength through the low-frequency monitoring signal and the bearing rotation speed includes: taking the lowest energy intensity value corresponding to the low-frequency monitoring signal of the bearing at different rotation speeds as the optimal lubrication baseline strength.

[0018] In one embodiment of the present invention, after obtaining the fused decibel value, the method further includes:

[0019] Obtaining the lowest energy intensity value corresponding to the low-frequency monitoring signal of the bearing at the current speed, and recording it as the current monitoring signal energy intensity; and recording the lowest energy intensity value corresponding to the optimal lubrication baseline intensity at the current speed as the original optimal lubrication baseline intensity;

[0020] Comparing the current monitoring signal energy intensity with the original optimal lubrication baseline intensity;

[0021] When the current monitoring signal energy intensity is less than the original optimal lubrication baseline intensity, the original optimal lubrication baseline intensity is replaced by the current monitoring signal energy intensity, and the optimal lubrication baseline is updated; wherein the optimal lubrication baseline is generated based on the optimal lubrication baseline intensity;

[0022] When the energy intensity of the current monitoring signal is greater than or equal to the original optimal lubrication baseline intensity, the optimal lubrication baseline is not updated.

[0023] In one embodiment of the present invention, the process of fusing the energy intensity of the low-frequency monitoring signal with the optimal lubrication baseline intensity to obtain the fused decibel value includes:

[0024] The energy intensity of the low-frequency monitoring signal and the optimal lubrication baseline intensity are input into a calculation model established in advance or in real time for fusion calculation to obtain the fused decibel value; wherein the calculation model includes:

[0025] dB 融 =20*lg(R 测 / R 基 );

[0026] In the formula, dB 融 Indicates the fusion decibel value;

[0027] R 测 Indicates the energy intensity of the low-frequency monitoring signal;

[0028] R 基 Indicates the optimal lubrication baseline intensity.

[0029] In one embodiment of the present invention, the method further comprises: acquiring an original ultrasonic signal generated during the operation of the bearing by means of an ultrasonic sensor mounted on the surface of the outer ring of the bearing.

[0030] The present invention also provides a bearing lubrication status monitoring device, the device comprising:

[0031] A signal acquisition unit, used to obtain the original ultrasonic signal generated during the operation of the bearing through an ultrasonic sensor fitted on the surface of the outer ring of the bearing;

[0032] A signal preprocessing unit is used to amplify the original ultrasonic signal through an amplifier circuit to obtain an amplified ultrasonic signal; and extract a sub-signal of the amplified ultrasonic signal in the optimal monitoring frequency band through a bandpass filter circuit, which is recorded as a first sub-signal; and perform heterodyne frequency reduction processing on the first sub-signal through a heterodyne circuit and a low-pass filter circuit to obtain a low-frequency monitoring signal; wherein the optimal monitoring frequency band is used to characterize the lubrication state of the bearing;

[0033] The main control unit is used to calculate the energy intensity of the low-frequency monitoring signal and fuse it with the optimal lubrication baseline intensity to obtain a fused decibel value; and compare the fused decibel value with a preset decibel threshold, and monitor the bearing lubrication status based on the comparison result; wherein the optimal lubrication baseline intensity is determined by the low-frequency monitoring signal and the bearing rotation speed.

[0034] In one embodiment of the present invention, the device further comprises:

[0035] The signal conversion unit is connected to the signal preprocessing unit and the main control unit respectively, and is used to convert the low-frequency monitoring signal that has been power amplified into a digital signal, and transmit the converted digital signal to the main control unit, so that the main control unit calculates the energy intensity of the low-frequency monitoring signal based on the converted digital signal.

[0036] In one embodiment of the present invention, the signal preprocessing unit is further provided with a power amplifier circuit, and the power amplifier circuit is used to perform power amplification processing on the first sub-signal after heterodyne frequency reduction processing to obtain a power-amplified low-frequency monitoring signal.

[0037] In one embodiment of the present invention, the device further comprises:

[0038] An earphone interface, the earphone interface is connected to the power amplifier circuit and is used for listening to the lubrication status of the bearing through the earphone;

[0039] A power supply unit, connected to the signal acquisition unit, the signal preprocessing unit, the main control unit and the signal conversion unit, and used to provide power;

[0040] The human-machine interaction unit is connected to the main control unit and is used to start bearing lubrication status monitoring and display bearing lubrication status monitoring results.

[0041] As described above, the present invention provides a bearing lubrication state monitoring method and device, which has the following beneficial effects: In view of the problems that the existing lubrication state evaluation index is complex to obtain, and the evaluation process lacks adaptability and is cumbersome, the present invention proposes a fusion decibel index calculation method and a comparative baseline adaptive adjustment method, which can avoid the complex acquisition process of conventional sound pressure decibels, and more accurately, quickly and intuitively reflect the difference between the current state of the bearing and the optimal lubrication state, while ensuring the reliability of the bearing lubrication state monitoring results and improving the efficiency of bearing lubrication state monitoring. At the same time, in view of the problem of insufficient means for obtaining the optimal monitoring frequency band of the bearing lubrication state, the present invention proposes an optimal monitoring frequency band identification scheme based on the analysis of the change trend of signal strength of different frequency bands of the bearing at different speeds when different grease injection amounts are used. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1A schematic diagram of a flow chart of a bearing lubrication status monitoring method provided by an embodiment of the present invention;

[0043] Figure 2 A schematic flow chart of a bearing lubrication status monitoring method provided in another embodiment of the present invention;

[0044] Figure 3 A schematic diagram of a process for identifying an optimal monitoring frequency band provided by an embodiment of the present invention;

[0045] Figure 4 A schematic diagram of the hardware structure of a bearing lubrication status monitoring device provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0046] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0047] It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner. Therefore, the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0048] Figure 1 FIG. 1 is a flow chart of a bearing lubrication status monitoring method according to an embodiment of the present invention. Specifically, in an exemplary embodiment, Figure 1 As shown, this embodiment provides a bearing lubrication state monitoring method, the method comprising the following steps:

[0049] S110, obtaining the original ultrasonic signal generated during the operation of the bearing. As an example, in this embodiment or other embodiments, the original ultrasonic signal generated during the operation of the bearing can be obtained by an ultrasonic sensor mounted on the surface of the outer ring of the bearing.

[0050] S120, amplify the original ultrasonic signal to obtain an amplified ultrasonic signal. As an example, the original ultrasonic signal can be amplified by an amplifier circuit to obtain an amplified ultrasonic signal. In this embodiment or other embodiments, the selection or setting of the amplifier circuit can be determined according to the specific application scenario, and this embodiment will not be repeated here.

[0051] S130, extract the sub-signal of the amplified ultrasonic signal in the optimal monitoring frequency band, and record it as the first sub-signal; wherein the optimal monitoring frequency band is used to characterize the lubrication state of the bearing. As an example, in this embodiment or other embodiments, the sub-signal of the amplified ultrasonic signal in the optimal monitoring frequency band can be extracted by a bandpass filter circuit to obtain the first sub-signal. As an example, in this embodiment or other embodiments, the process of identifying the optimal monitoring frequency band includes: collecting multiple ultrasonic signals generated by the bearing at different speeds when different grease injection amounts are used; performing spectrum analysis on the multiple ultrasonic signals, and selecting multiple frequency bands in each ultrasonic signal segment whose energy density concentration is greater than a preset threshold; extracting the sub-signal of each ultrasonic signal in multiple frequency bands, and recording it as the second sub-signal, and calculating the energy intensity of the second sub-signal; based on the change in the amount of grease injection, selecting the frequency band with the consistent change trend of the energy intensity of the second sub-signal at different speeds as the optimal monitoring frequency band. In this embodiment, the preset threshold can be selected or set according to the actual situation, and this embodiment will not be repeated here. In this embodiment or other embodiments, the amount of grease injection refers to the amount of grease injected into the bearing for bearing lubrication.

[0052] S140, heterodyne down-converting the first signal to obtain a low-frequency monitoring signal. As an example, in this embodiment or other embodiments, the first signal can be heterodyne processed by a heterodyne circuit, and the first signal after heterodyne processing can be down-converted by a low-pass filter circuit to obtain a low-frequency monitoring signal.

[0053] S150, calculating the energy intensity of the low-frequency monitoring signal, and fusing it with the optimal lubrication baseline intensity to obtain a fused decibel value; wherein the optimal lubrication baseline intensity is determined by the low-frequency monitoring signal and the rotational speed of the bearing. As an example, in this embodiment or other embodiments, the process of fusing the energy intensity of the low-frequency monitoring signal with the optimal lubrication baseline intensity to obtain a fused decibel value includes: inputting the energy intensity of the low-frequency monitoring signal and the optimal lubrication baseline intensity into a calculation model established in advance or in real time for fusion calculation to obtain a fused decibel value; wherein the calculation model includes: dB 融 =20*lg(R 测 / R 基 );wherein, dB 融 Indicates the fusion decibel value; R 测 Represents the energy intensity of the low-frequency monitoring signal; R 基 Indicates the optimal lubrication baseline intensity. As an example, in this embodiment or other embodiments, the process of determining the optimal lubrication baseline intensity through the low-frequency monitoring signal and the rotational speed of the bearing includes: taking the lowest energy intensity value corresponding to the low-frequency monitoring signal of the bearing at different rotational speeds as the optimal lubrication baseline intensity.

[0054] S160, comparing the fused decibel value with a preset decibel threshold, and monitoring the bearing lubrication state based on the comparison result. In this embodiment or other embodiments, the preset decibel threshold can be selected or set according to actual conditions, for example, the preset decibel threshold can be set to 0dB, 8dB, 12dB, 16dB, 35-50dB, etc.

[0055] According to the above records, in an exemplary embodiment, after obtaining the fused decibel value, the embodiment may also include: obtaining the minimum energy intensity value corresponding to the low-frequency monitoring signal of the bearing at the current speed, recorded as the current monitoring signal energy intensity; and, recording the minimum energy intensity value corresponding to the optimal lubrication baseline intensity at the current speed as the original optimal lubrication baseline intensity. Compare the current monitoring signal energy intensity with the original optimal lubrication baseline intensity; when the current monitoring signal energy intensity is less than the original optimal lubrication baseline intensity, use the current monitoring signal energy intensity to replace the original optimal lubrication baseline intensity, and update the optimal lubrication baseline; wherein, the optimal lubrication baseline is generated based on the optimal lubrication baseline intensity. When the current monitoring signal energy intensity is greater than or equal to the original optimal lubrication baseline intensity, the optimal lubrication baseline is not updated.

[0056] In another exemplary embodiment of the present invention, Figure 2 As shown, this embodiment also provides a bearing lubrication status monitoring method, the method comprising the following steps:

[0057] S11, identifying the optimal ultrasonic monitoring frequency band that can characterize the lubrication state of the target bearing. As an example, in this embodiment, the optimal monitoring frequency band obtained for the rolling bearing is 20KHZ-30KHZ.

[0058] S12, during monitoring, the original ultrasonic signal generated during the operation of the bearing is obtained, and amplified to obtain an amplified ultrasonic signal. In this embodiment, the ultrasonic original signal within the bandwidth range of 0-40KHZ can be obtained by an ultrasonic sensor, and the signal is amplified by a two-stage amplifier circuit to obtain an amplified ultrasonic signal.

[0059] S13, extracting the sub-signal of the amplified ultrasonic signal in the optimal monitoring frequency band through bandpass filtering. In this embodiment, after the amplified ultrasonic signal is input into the 20KHZ-30KHZ bandpass filter circuit, the 20KHZ-30KHZ bandpass filter circuit filters out redundant information and retains the sub-signal of the amplified ultrasonic signal in the optimal monitoring frequency band, i.e., the optimal characterization signal of the bearing lubrication state.

[0060] S14, heterodyne frequency reduction processing is performed on the sub-signal of the amplified ultrasonic signal in the optimal monitoring frequency band to obtain a low-frequency monitoring signal. In this embodiment, according to the heterodyne frequency reduction principle and the above-mentioned optimal monitoring frequency band of 20KHZ-30KHZ, the oscillation frequency of the heterodyne circuit can be set to 20KHZ, and the signal after heterodyne processing by the heterodyne circuit includes a difference frequency signal and a sum frequency signal, and the frequency band ranges are [0KHZ-10KHZ] and [40KHZ-50KHZ] respectively. The signal after heterodyne processing by the heterodyne circuit continues to enter the low-frequency filter circuit, filters out the sum frequency signal and retains the difference frequency signal with a frequency band of [0KHZ-10KHZ] as the low-frequency monitoring signal.

[0061] S15. Calculate the energy intensity of the low-frequency monitoring signal, and fuse it with the optimal lubrication baseline intensity to obtain a fused decibel value, and determine whether to update the optimal lubrication baseline. The signal energy intensity in this embodiment is the signal root mean square value. Specifically, the low-frequency monitoring signal is power amplified and analog-to-digital converted before calculating the signal energy intensity, that is, calculating the signal root mean square value. The calculation result and the pre-stored optimal lubrication intensity value are calculated according to the following calculation formula to obtain a fused decibel value. The calculation formula is: dBfusion = 20*lg (Rmeasured / Rbase); wherein Rmeasured is the energy intensity of the low-frequency monitoring signal obtained in real time, and Rbase is the optimal lubrication baseline intensity. At the same time, determine whether the current signal strength is less than the pre-stored optimal lubrication baseline intensity. If so, the optimal lubrication baseline intensity is changed to the current signal strength; if not, the pre-stored optimal lubrication baseline intensity is maintained unchanged.

[0062] S16. Compare the fusion decibel value with the preset decibel threshold, and judge the bearing lubrication status based on the comparison result. In this embodiment, the specific process of judging the bearing lubrication status according to the fusion decibel value includes: 1) When the fusion decibel value is less than 0dB, it indicates that the bearing has entered a new optimal lubrication state, and the pre-stored optimal lubrication baseline intensity needs to be updated. 2) When the fusion decibel value is equal to 0dB, it indicates that the bearing is at the optimal lubrication point and no processing is required. 3) When the fusion decibel value exceeds 8dB, it indicates that the bearing is in an under-lubricated state and grease needs to be added. 4) When the fusion decibel value exceeds 12dB, it indicates that the bearing has entered a fault mode and necessary maintenance measures need to be taken to prevent the fault from aggravating. 5) When the fusion decibel value exceeds 16dB, it indicates that the bearing fault has further expanded and deepened. 6) When the fusion decibel value exceeds 35dB-50dB, it indicates that a catastrophic accident based on a bearing fault may occur at any time, and the bearing needs to be stopped immediately for replacement.

[0063] According to the above records, in this embodiment, the process of identifying the optimal monitoring frequency band is as follows: Figure 3 Specifically, identifying the optimal monitoring frequency band includes the following steps:

[0064] S21, collecting multiple ultrasonic signals generated by the bearing at different speeds when different grease injection amounts are used. In this embodiment, for rolling bearings, five rolling bearings with grease injection amounts of 0g, 4.5g, 5.5g, 6.9g, and 9.0g are selected, and ultrasonic signals of the five bearings are collected at six different speeds of 100r / m, 200r / m, 300r / m, 500r / m, 800r / m, and 1000r / m, and 30 ultrasonic original signals are obtained in total.

[0065] S22, performing spectrum analysis on multiple ultrasonic signals, and selecting multiple frequency bands where energy density is concentrated in each ultrasonic signal. In this embodiment, the spectrum analysis is performed on the above 30 ultrasonic original signals, and the energy of all signal spectra is mainly concentrated in the low frequency range of 20k-30k and the high frequency range of 80k-120k, that is, two frequency bands with concentrated energy density are obtained.

[0066] S23, extract the sub-signals of each ultrasonic signal in multiple frequency bands, and calculate the energy intensity of the sub-signals of each ultrasonic signal in multiple frequency bands. In this embodiment, the above 30 segments of ultrasonic original signals are bandpass filtered to obtain their sub-signals in the 20KHZ-30KHZ frequency band and the 80KHZ-120KHZ frequency band, and 60 segments of sub-signals are accumulated. Calculate the energy intensity of the 60 segments of sub-signals, and calculate their signal root mean square values ​​here. The signal root mean square value calculation method is as follows: In the formula, x i represents the signal amplitude of the i-th sampling point, and n represents the total number of sampling points.

[0067] S24. As the amount of fat injected increases, the frequency band with the most consistent change trend of the energy intensity of the sub-signals of each segment of the ultrasonic signal in multiple frequency bands at different rotational speeds is selected as the optimal monitoring frequency band. In this embodiment, by analyzing the intensity change trend of the sub-signals of the two frequency bands at different fat injection amounts and different rotational speeds, such as taking the fat injection amount as the horizontal axis and the rotational speed as the vertical axis, the intensity change curves of the sub-signals in the two frequency bands are drawn respectively. The frequency band with the most consistent intensity change trend of different fat amounts at different rotational speeds is selected as the optimal frequency band. In this embodiment, the frequency band finally selected in the current monitoring scenario is 20KHZ-30KHZ.

[0068] In summary, the present invention provides a bearing lubrication state monitoring method, by obtaining the original ultrasonic signal generated during the operation of the bearing, and amplifying the original ultrasonic signal to obtain an amplified ultrasonic signal; and extracting the sub-signal of the amplified ultrasonic signal in the optimal monitoring frequency band, recorded as the first sub-signal; wherein the optimal monitoring frequency band is used to characterize the bearing lubrication state; then heterodyne frequency reduction processing is performed on the first sub-signal to obtain a low-frequency monitoring signal; and the energy intensity of the low-frequency monitoring signal is calculated, and fused with the optimal lubrication baseline intensity to obtain a fused decibel value; wherein the optimal lubrication baseline intensity is determined by the low-frequency monitoring signal and the rotation speed of the bearing; finally, the fused decibel value is compared with the preset decibel threshold, and the bearing lubrication state is monitored based on the comparison result. It can be seen that the method aims at the problems that the existing lubrication state evaluation index is complex to obtain, the evaluation process lacks self-adaptation and is cumbersome, and proposes a fused decibel index calculation method and a comparison baseline adaptive adjustment method, which can avoid the complex acquisition process of conventional sound pressure decibels, and more accurately, quickly and intuitively reflect the difference between the current state of the bearing and the optimal lubrication state, while ensuring the reliability of the bearing lubrication state monitoring results while improving the efficiency of bearing lubrication state monitoring. At the same time, this method aims to solve the problem of insufficient means to obtain the optimal monitoring frequency band of the bearing lubrication status, and proposes an optimal monitoring frequency band identification scheme based on the analysis of the change trend of signal intensity of different frequency bands of the bearing at different speeds when the amount of grease injection is different.

[0069] In another exemplary embodiment of the present invention, Figure 4 As shown, this embodiment also provides a bearing lubrication status monitoring device, including:

[0070] A signal acquisition unit, used to obtain the original ultrasonic signal generated during the operation of the bearing through an ultrasonic sensor fitted on the surface of the outer ring of the bearing;

[0071] The signal preprocessing unit is used to amplify the original ultrasonic signal through an amplifier circuit to obtain an amplified ultrasonic signal; and extract the sub-signal of the amplified ultrasonic signal in the optimal monitoring frequency band through a bandpass filter circuit, which is recorded as the first sub-signal; and perform heterodyne frequency reduction processing on the first sub-signal through a heterodyne circuit and a low-pass filter circuit to obtain a low-frequency monitoring signal; and perform power amplification processing on the first sub-signal after heterodyne frequency reduction processing through a power amplifier circuit to obtain a power-amplified low-frequency monitoring signal, wherein the optimal monitoring frequency band is used to characterize the bearing lubrication state. In this embodiment or other embodiments, the filter circuit is built based on the MAX275 filter chip, the center frequency of the bandpass filter is 25KHZ, the quality factor is 2.5, the center frequency of the low-pass filter is 10KHZ, and the quality factor is 0.707. The heterodyne circuit is built with an XR-2206 signal generator chip, and the internal oscillation signal frequency is set to 20KHZ. After multiplying with the bandpass monitoring signal at the input end, a 0KHZ-10KHZ difference frequency signal and a 40KHZ-50KHZ sum frequency signal are obtained. After passing through the low-pass filter, the difference frequency monitoring signal of 0KHZ-10KHZ is obtained.

[0072] The signal conversion unit is connected to the signal preprocessing unit and the main control unit respectively, and is used to convert the low-frequency monitoring signal after power amplification into a digital signal, and transmit the converted digital signal to the main control unit, so that the main control unit calculates the energy intensity of the low-frequency monitoring signal based on the converted digital signal. In this embodiment or other embodiments, an analog-to-digital signal conversion scheme based on a 16-bit serial ADC chip ADS7866 is adopted to convert the analog difference frequency monitoring signal at the input end into a digital difference frequency monitoring signal, and transmit it to the main control unit for processing through a serial SPI interface.

[0073] The main control unit is used to calculate the energy intensity of the low-frequency monitoring signal and fuse it with the optimal lubrication baseline intensity to obtain a fused decibel value; and compare the fused decibel value with a preset decibel threshold, and monitor the bearing lubrication state based on the comparison result; wherein the optimal lubrication baseline intensity is determined by the low-frequency monitoring signal and the rotation speed of the bearing. In this embodiment or other embodiments, the main control unit uses the OMAP-L138 chip as the main control core, and the calculation processing program is deployed in the DSP core of the main control chip.

[0074] According to the above records, in an exemplary embodiment, the bearing lubrication state monitoring device may also include:

[0075] The headphone interface is connected to the power amplifier circuit and is used to listen to the bearing lubrication status through the headphone. In this embodiment, the headphone interface is arranged behind the power amplifier circuit, and the effective monitoring signal after frequency reduction can be directly heard by plugging in the headphone.

[0076] The human-machine interaction unit is connected to the main control unit and is used to start bearing lubrication status monitoring and display bearing lubrication status monitoring results. In this embodiment, a touch screen can be used to form the human-machine interaction unit, which is connected to the main control unit through the LCD peripheral interface of the main control chip for human-machine interaction, including starting bearing lubrication status monitoring, bearing lubrication status monitoring results display, and bearing lubrication status monitoring parameter configuration and confirmation.

[0077] The power supply unit is connected to the signal acquisition unit, the signal preprocessing unit, the main control unit and the signal conversion unit, and is used to provide power to the signal acquisition unit, the signal preprocessing unit, the main control unit and the signal conversion unit. In this embodiment, for the ±5V power supply requirements of the operational amplifier circuit and the heterodyne circuit, the input 9V voltage is stabilized to +5V output through LM1086-5, and the 5V voltage is stabilized to -5V output based on MC7660 in parallel; for the +3.3V power supply requirements of the microprocessor chip, A / D conversion chip, etc., the +5V voltage is stabilized to 3.3V output based on the TPS65023 power management chip.

[0078] In summary, the present invention provides a bearing lubrication state monitoring device, which obtains the original ultrasonic signal generated during the operation of the bearing, and amplifies the original ultrasonic signal to obtain an amplified ultrasonic signal; and extracts the sub-signal of the amplified ultrasonic signal in the optimal monitoring frequency band, which is recorded as the first sub-signal; wherein the optimal monitoring frequency band is used to characterize the bearing lubrication state; and then heterodyne frequency reduction processing is performed on the first sub-signal to obtain a low-frequency monitoring signal; and the energy intensity of the low-frequency monitoring signal is calculated, and fused with the optimal lubrication baseline intensity to obtain a fused decibel value; wherein the optimal lubrication baseline intensity is determined by the low-frequency monitoring signal and the rotation speed of the bearing; finally, the fused decibel value is compared with the preset decibel threshold, and the bearing lubrication state is monitored based on the comparison result. It can be seen that the present device aims at the problems that the acquisition of existing lubrication state evaluation indicators is complex, the evaluation process lacks adaptability and is cumbersome, and proposes a fused decibel indicator calculation method and a comparison baseline adaptive adjustment method, which can avoid the complex acquisition process of conventional sound pressure decibels, and more accurately, quickly and intuitively reflect the difference between the current state of the bearing and the optimal lubrication state, while ensuring the reliability of the bearing lubrication state monitoring results and improving the efficiency of bearing lubrication state monitoring. At the same time, in order to solve the problem of insufficient means to obtain the optimal monitoring frequency band for the lubrication status of the bearing, this device proposes an optimal monitoring frequency band identification scheme based on the analysis of the changing trend of signal intensity of different frequency bands of the bearing at different speeds when the amount of grease injected is different.

[0079] It should be noted that the bearing lubrication state monitoring device provided in the above embodiment and the bearing lubrication state monitoring method provided in the above embodiment belong to the same concept, wherein the specific manner in which the bearing lubrication state monitoring method performs operations has been described in detail in the above method embodiment, and will not be repeated here. In actual applications, the bearing lubrication state monitoring device provided in the above embodiment can allocate the above functions to different functional modules as needed, that is, divide the internal structure of the bearing lubrication state monitoring device into different functional modules, and then implement all or part of the functions of the corresponding functional modules through the bearing lubrication state monitoring method described in the above embodiment, and this is not specifically limited here.

[0080] It should be understood that, although the terms first, second, etc. may be used to describe sub-signals, etc. in the embodiments of the present invention, these terms are only used to distinguish sub-signals from each other. For example, without departing from the scope of the embodiments of the present invention, the first sub-signal may also be referred to as the second sub-signal, and similarly, the second sub-signal may also be referred to as the first sub-signal.

[0081] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A bearing lubrication status monitoring method, characterized in that: The method comprises the following steps: Acquire the original ultrasonic signal generated during the operation of the bearing; amplifying the original ultrasonic signal to obtain an amplified ultrasonic signal; Extracting a sub-signal of the amplified ultrasonic signal in the optimal monitoring frequency band and recording it as a first sub-signal; wherein the optimal monitoring frequency band is used to characterize the lubrication state of the bearing; Performing heterodyne frequency reduction processing on the first branch signal to obtain a low-frequency monitoring signal; Calculate the energy intensity of the low-frequency monitoring signal and fuse it with the optimal lubrication baseline intensity to obtain a fused decibel value; wherein the optimal lubrication baseline intensity is determined by the low-frequency monitoring signal and the rotational speed of the bearing; The fused decibel value is compared with a preset decibel threshold, and the bearing lubrication status is monitored based on the comparison result.

2. The bearing lubrication status monitoring method according to claim 1, characterized in that: The process of identifying the optimal monitoring frequency band includes: Collect multiple ultrasonic signals generated by the bearing at different speeds when different grease injection amounts are applied; Performing spectrum analysis on the multiple ultrasonic signals, and selecting multiple frequency bands whose energy density concentration is greater than a preset threshold in each ultrasonic signal segment; Extracting sub-signals of each segment of the ultrasonic signal in the multiple frequency bands, recording them as second sub-signals, and calculating the energy intensity of the second sub-signals; Based on the change in the amount of injected fat, a frequency band in which the energy intensity of the second component signal has a consistent change trend at different rotation speeds is selected as the optimal monitoring frequency band.

3. The bearing lubrication status monitoring method according to claim 1, characterized in that: The process of determining the optimal lubrication baseline intensity through the low-frequency monitoring signal and the rotational speed of the bearing includes: taking the lowest energy intensity value corresponding to the low-frequency monitoring signal of the bearing at different rotational speeds as the optimal lubrication baseline intensity.

4. The bearing lubrication status monitoring method according to claim 1 or 3, characterized in that: After obtaining the fused decibel value, the method further includes: Obtaining the lowest energy intensity value corresponding to the low-frequency monitoring signal of the bearing at the current speed, and recording it as the current monitoring signal energy intensity; and recording the lowest energy intensity value corresponding to the optimal lubrication baseline intensity at the current speed as the original optimal lubrication baseline intensity; Comparing the current monitoring signal energy intensity with the original optimal lubrication baseline intensity; When the current monitoring signal energy intensity is less than the original optimal lubrication baseline intensity, the original optimal lubrication baseline intensity is replaced by the current monitoring signal energy intensity, and the optimal lubrication baseline is updated; wherein the optimal lubrication baseline is generated based on the optimal lubrication baseline intensity; When the energy intensity of the current monitoring signal is greater than or equal to the original optimal lubrication baseline intensity, the optimal lubrication baseline is not updated.

5. The bearing lubrication status monitoring method according to claim 1, characterized in that: The process of fusing the energy intensity of the low-frequency monitoring signal with the optimal lubrication baseline intensity to obtain the fused decibel value includes: The energy intensity of the low-frequency monitoring signal and the optimal lubrication baseline intensity are input into a calculation model established in advance or in real time for fusion calculation to obtain the fused decibel value; wherein the calculation model includes: dB 融 =20*lg(R 测 / R 基 ); In the formula, dB 融 Indicates the fusion decibel value; R 测 Indicates the energy intensity of the low-frequency monitoring signal; R 基 Indicates the optimal lubrication baseline intensity.

6. The bearing lubrication status monitoring method according to claim 1, characterized in that: The method further comprises: acquiring an original ultrasonic signal generated during the operation of the bearing by means of an ultrasonic sensor mounted on the surface of the outer ring of the bearing.

7. A bearing lubrication status monitoring device, characterized in that: The device comprises: A signal acquisition unit, used to obtain the original ultrasonic signal generated during the operation of the bearing through an ultrasonic sensor fitted on the surface of the outer ring of the bearing; A signal preprocessing unit is used to amplify the original ultrasonic signal through an amplifier circuit to obtain an amplified ultrasonic signal; and extract a sub-signal of the amplified ultrasonic signal in the optimal monitoring frequency band through a bandpass filter circuit, which is recorded as a first sub-signal; and perform heterodyne frequency reduction processing on the first sub-signal through a heterodyne circuit and a low-pass filter circuit to obtain a low-frequency monitoring signal; wherein the optimal monitoring frequency band is used to characterize the lubrication state of the bearing; The main control unit is used to calculate the energy intensity of the low-frequency monitoring signal and fuse it with the optimal lubrication baseline intensity to obtain a fused decibel value; and compare the fused decibel value with a preset decibel threshold, and monitor the bearing lubrication status based on the comparison result; wherein the optimal lubrication baseline intensity is determined by the low-frequency monitoring signal and the bearing rotation speed.

8. The bearing lubrication status monitoring device according to claim 7, characterized in that: The device also includes: The signal conversion unit is connected to the signal preprocessing unit and the main control unit respectively, and is used to convert the low-frequency monitoring signal that has been power amplified into a digital signal, and transmit the converted digital signal to the main control unit, so that the main control unit calculates the energy intensity of the low-frequency monitoring signal based on the converted digital signal.

9. The bearing lubrication status monitoring device according to claim 8, characterized in that: The signal preprocessing unit is further provided with a power amplifier circuit, and the power amplifier circuit is used to perform power amplification processing on the first sub-signal after heterodyne frequency reduction processing to obtain a power-amplified low-frequency monitoring signal.

10. The bearing lubrication status monitoring device according to claim 9, characterized in that: The device also includes: An earphone interface, the earphone interface is connected to the power amplifier circuit and is used for listening to the lubrication status of the bearing through the earphone; A power supply unit, connected to the signal acquisition unit, the signal preprocessing unit, the main control unit and the signal conversion unit, and configured to provide power; The human-machine interaction unit is connected to the main control unit and is used to start bearing lubrication status monitoring and display bearing lubrication status monitoring results.

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