Typical small bearing weak fault comprehensive diagnosis standard construction method

Abstract

The invention belongs to the technical field of transmission casing bearing fault diagnosis, and particularly relates to a typical small bearing weak fault comprehensive diagnosis standard construction method, which comprises the following steps: respectively carrying out inner ring, outer ring and rolling body bearing fault simulation tests; a filtering frequency band is selected based on a weighted kurtosis value improved Protugram algorithm, an envelope spectrum is extracted after filtering and noise reduction, and a bearing fault diagnosis standard threshold value is established based on an envelope spectrum characteristic value method; based on a preset fault test, comprehensively analyzing envelope spectrum characteristic values of different faults and different measuring points, and establishing a comprehensive early warning diagnosis standard; based on a failure fault test, envelope spectrum characteristic values of different faults and different measuring points are comprehensively analyzed, and a comprehensive failure diagnosis standard is established. And after judging that the bearing has no fault, respectively carrying out a preset fault test and a failure fault test, and establishing an early warning diagnosis threshold value and a failure standard threshold value for the fault characteristic sensitive measuring points on the basis of measuring point optimization analysis, thereby realizing early warning and failure judgment of the bearing fault.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of transmission gearbox bearing fault diagnosis, and particularly relates to a construction method of a typical small bearing weak fault comprehensive diagnosis standard. BACKGROUND

[0002] As a key component of power transmission of aircraft accessories, the transmission gearbox has multiple operating conditions, a harsh environment, a complex internal structure, many components, small size and precision, gears, shafts and bearings are closely coupled and interact with each other, resulting in a very complex bearing fault signal transmission path. When the bearing has spalling failure, the fault impact will cause high-frequency vibration of the structure, and based on the high-frequency vibration signal characteristic parameters, there is a clear physical meaning, and corresponding to different fault types, bearing condition monitoring and fault diagnosis are mostly based on high-frequency vibration signals. However, under the airborne conditions, it is difficult to accurately extract the bearing fault characteristics due to the few measuring points (one measuring point for each of the fly-by and the launch attachment), the many vibration interferences and the weak fault signals, which limits the establishment of the online automatic high-reliability diagnosis method and the comprehensive technical diagnosis standard for the weak fault of the small bearing of the transmission gearbox.

[0003] Therefore, how to realize the comprehensive diagnosis standard of the typical small bearing weak fault is a problem to be solved. SUMMARY

[0004] The purpose of the present application is to provide a construction method of a typical small bearing weak fault comprehensive diagnosis standard, so as to solve the problem that the existing airborne conditions limit the online automatic high-reliability diagnosis of the weak fault of the small bearing of the transmission gearbox due to the few measuring points, the many vibration interferences and the weak fault signals.

[0005] The technical scheme of the present application is: a construction method of a typical small bearing weak fault comprehensive diagnosis standard, comprising:

[0006] Developing inner ring, outer ring and rolling element bearing fault simulation tests, respectively obtaining corresponding test data;

[0007] Using the Protugram algorithm based on the improved weighted kurtosis value to select the filter frequency band corresponding to different test data for filtering and noise reduction to obtain the impact-enhanced reconstructed signal , extracting the envelope spectrum after filtering and noise reduction for envelope demodulation to obtain the envelope spectrum absolute energy value, the envelope spectrum characteristic value and the quantitative diagnosis threshold value respectively; establishing a fault judgment relationship based on the quantitative diagnosis threshold value; when the fault judgment relationship judges that the bearing is fault-free, performing a preset fault test and a failure fault test;

[0008] Obtaining the envelope spectrum characteristic value data of the preset fault test, comprehensively analyzing the envelope spectrum characteristic values of different faults and different measuring points, and establishing a comprehensive early warning diagnosis relationship;

[0009] The envelope spectrum characteristic value data of the failure fault test is acquired, the envelope spectrum characteristic values of different faults and different measuring points are comprehensively analyzed, a comprehensive failure diagnosis standard is established, and then a failure diagnosis relationship is established by setting a failure standard threshold.

[0010] Preferably, the envelope demodulation method is: calculating the amplitude values of the fault characteristic frequency and its harmonics in the envelope spectrum; on this basis, the impact value is quantified to obtain an impact enhanced reconstruction signal ; and based on the impact enhanced reconstruction signal , the amplitude value corresponding to the rotation frequency is calculated, and then the envelope spectrum characteristic value is calculated based on the amplitude value corresponding to the rotation frequency.

[0011] Preferably, the method for calculating the bearing failure diagnosis standard threshold is specifically:

[0012] The impact enhanced reconstruction signal after matched pursuit denoising is subjected to Hilbert envelope demodulation to obtain an envelope spectrum signal , the peak energy value at the bearing fault characteristic frequency is calculated and standardized, and the peak energy value at the bearing fault characteristic frequency is taken as a characteristic index for measuring the bearing fault degree;

[0013] The envelope spectrum absolute energy value, the envelope spectrum characteristic value and the quantitative diagnosis threshold are obtained after the peak energy value at the bearing fault characteristic frequency is standardized.

[0014] Preferably, the envelope spectrum absolute energy value is obtained by:

[0015] The impact pulse method represents the fault impact energy by the impact amplitude in the time domain waveform; according to the Parseval theorem, the energy of a signal has the equivalence in the time domain and the frequency domain; therefore, the sum of the amplitude values at the fault characteristic frequency and its harmonics in the envelope spectrum is taken as the representation of the envelope spectrum absolute energy value, that is:

[0016]

[0017] In the formula, is the sum of the peak energy values at the envelope spectrum fault characteristic frequency and its M-order harmonics, represents the amplitude value corresponding to the frequency in the signal envelope spectrum.

[0018] Preferably, the envelope spectrum characteristic value is obtained by: taking the amplitude value corresponding to the rotation component amplitude in the original signal spectrum as the measurement of the rotation speed and the load, thereby standardizing the envelope spectrum peak energy value, converting the unit into dB value, and finally calculating the mean value of the energy peak values at the various fault characteristic frequencies and their harmonics as the final envelope spectrum characteristic value;

[0019] ​The envelope spectrum characteristic value calculation formula is as follows:

[0020]

[0021] In the formula, represents the normalized energy value at each frequency in the signal envelope spectrum, in dB, represents the corresponding amplitude of the original signal spectrum at the frequency, represents the corresponding amplitude of the original signal spectrum at the frequency, represents the rotation frequency;

[0022]

[0023] In the formula, represents the envelope spectrum characteristic value of the fault characteristic frequency.

[0024] Preferably, the quantitative diagnosis threshold value acquisition method is:

[0025] The envelope spectrum characteristic values corresponding to the four fault characteristic frequencies are calculated, and the maximum value among them is selected as the envelope spectrum characteristic value; the set fault determination threshold value is an empirical value;

[0026] The fault determination relationship is:

[0027] (4)

[0028] In the formula, represents the maximum value in the set R, and R is the set of envelope spectrum characteristic values; is the fault determination threshold value.

[0029] If the above formula is satisfied, it indicates that the bearing has a fault.

[0030] Preferably, the envelope spectrum characteristic value data of the preset fault test is obtained, the Protugram algorithm based on the improved weighted kurtosis value is used to select the filter frequency band, the envelope spectrum is calculated after filtering and noise reduction, and the fault characteristic frequency and the amplitude of the multiple frequency are extracted from the envelope spectrum; the amplitude corresponding to the 1X rotation frequency is obtained by calculating the original signal speed spectrum; then, the envelope spectrum characteristic values of different faults and different measuring points are calculated based on the amplitude corresponding to the 1X rotation frequency; different early warning diagnosis threshold values are set for different faults and different measuring points, and a comprehensive early warning diagnosis relationship is established based on the envelope spectrum characteristic values of different faults and different measuring points and the early warning diagnosis threshold values.

[0031] Preferably, the failure diagnosis standards for different fault types of the inner ring, the outer ring and the rolling body are established based on the failure standard threshold value; different failure standard threshold values are set for the selected measuring points after the optimization analysis of the measuring points; the failure diagnosis relationship is obtained by combining the failure diagnosis standards and the failure standard threshold values, and the corresponding bearing failure is judged when the failure diagnosis standard exceeds the failure standard threshold value.​

[0032] Preferably, the envelope spectrum characteristic value about 2 hours before the end of the test is taken as the failure diagnosis criterion; and the minimum value of each measuring point under different faults is taken as the failure criterion threshold.

[0033] The method for constructing the comprehensive diagnosis criterion of the weak fault of the typical small bearing of the transmission case comprises the following steps: carrying out bearing fault simulation tests of inner rings, outer rings and rolling elements respectively; selecting a filter band based on the Protugram algorithm improved based on a weighted kurtosis value, extracting an envelope spectrum after filtering and noise reduction, and establishing a bearing fault diagnosis criterion threshold based on an envelope spectrum characteristic value method; comprehensively analyzing envelope spectrum characteristic values of different faults and different measuring points based on preset fault tests, and establishing a comprehensive early warning diagnosis criterion; comprehensively analyzing envelope spectrum characteristic values of different faults and different measuring points based on failure fault tests, and establishing a comprehensive failure diagnosis criterion.

[0034] The method for constructing the comprehensive diagnosis criterion of the weak fault of the typical small bearing of the transmission case comprises the following steps: carrying out bearing fault simulation tests of inner rings, outer rings and rolling elements respectively; selecting a filter band based on the Protugram algorithm improved based on a weighted kurtosis value, extracting an envelope spectrum after filtering and noise reduction, and establishing a bearing fault diagnosis criterion threshold based on an envelope spectrum characteristic value method; comprehensively analyzing envelope spectrum characteristic values of different faults and different measuring points based on preset fault tests, and establishing a comprehensive early warning diagnosis criterion; comprehensively analyzing envelope spectrum characteristic values of different faults and different measuring points based on failure fault tests, and establishing a comprehensive failure diagnosis criterion. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions provided by the present application, the following will briefly introduce the drawings. Obviously, the drawings described below are only some embodiments of the present application.

[0036] Figure 1 FIG. 1 is a flow chart of a method for constructing a comprehensive diagnosis criterion of a weak fault of a typical small bearing of a transmission case according to an embodiment of the present application;

[0037] Figure 2 FIG. 2 is a schematic diagram of a diagnosis result of a bearing outer ring fault measuring point 1 of the transmission case 209 according to an embodiment of the present application;

[0038] Figure 3 FIG. 3 is a schematic diagram of a diagnosis result of a bearing outer ring fault measuring point 3 of the transmission case 209 according to an embodiment of the present application;

[0039] Figure 4 FIG. 4 is a schematic diagram of a diagnosis result of a bearing outer ring fault measuring point 8 of the transmission case 209 according to an embodiment of the present application;

[0040] Figure 5 FIG. 5 is a schematic diagram of a diagnosis result of a bearing inner ring fault measuring point 1 of the transmission case 209 according to an embodiment of the present application;

[0041] Figure 6 FIG. 6 is a schematic diagram of a diagnosis result of a bearing inner ring fault measuring point 3 of the transmission case 209 according to an embodiment of the present application;

[0042] Figure 7is a schematic diagram of the diagnosis result of the bearing inner ring fault point 8 of the engine case 209 of the embodiment of the present application;

[0043] Figure 8 is a schematic diagram of the diagnosis result of the bearing rolling element fault point 1 of the engine case 209 of the embodiment of the present application;

[0044] Figure 9 is a schematic diagram of the diagnosis result of the bearing rolling element fault point 3 of the engine case 209 of the embodiment of the present application;

[0045] Figure 10 is a schematic diagram of the diagnosis result of the bearing rolling element fault point 8 of the engine case 209 of the embodiment of the present application;

[0046] Figure 11 is a schematic diagram of the bearing point 1 outer ring failure curve of the engine case 209 of the embodiment of the present application;

[0047] Figure 12 is a schematic diagram of the bearing point 3 outer ring failure curve of the engine case 209 of the embodiment of the present application;

[0048] Figure 13 is a schematic diagram of the bearing point 8 outer ring failure curve of the engine case 209 of the embodiment of the present application;

[0049] Figure 14 is a schematic diagram of the bearing point 1 inner ring failure curve of the engine case 209 of the embodiment of the present application;

[0050] Figure 15 is a schematic diagram of the bearing point 3 inner ring failure curve of the engine case 209 of the embodiment of the present application;

[0051] Figure 16 is a schematic diagram of the bearing point 8 inner ring failure curve of the engine case 209 of the embodiment of the present application;

[0052] Figure 17 is a schematic diagram of the bearing point 1 rolling element failure curve of the engine case 209 of the embodiment of the present application;

[0053] Figure 18 is a schematic diagram of the bearing point 3 rolling element failure curve of the engine case 209 of the embodiment of the present application;

[0054] Figure 19 is a schematic diagram of the bearing point 8 rolling element failure curve of the engine case 209 of the embodiment of the present application. DETAILED DESCRIPTION

[0055] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.

[0056] A method for constructing a comprehensive diagnostic standard for minor faults in typical small bearings, using data from the highest speed for analysis, such as... Figure 1 It includes the following steps:

[0057] Step S100: Conduct fault simulation tests on the inner ring, outer ring, and rolling element bearings, and obtain the corresponding test data respectively;

[0058] Step S200: The Protugram algorithm based on weighted kurtosis is used to select the filtering frequency band corresponding to different experimental data for filtering and noise reduction, thereby obtaining the impulse enhancement reconstructed signal. After filtering and noise reduction, the envelope spectrum is extracted and demodulated to obtain the absolute energy value, eigenvalue, and quantitative diagnostic threshold of the envelope spectrum. A fault determination formula is then established based on the quantitative diagnostic threshold. When the fault determination formula indicates that the bearing is fault-free, a preset fault test and a failure fault test are performed.

[0059] Preferably, the envelope demodulation method is as follows: calculate the fault characteristic frequencies and their harmonic amplitudes in the envelope spectrum; based on this, perform impulse value quantization to obtain the impulse-enhanced reconstructed signal. ; and based on the impact-enhanced reconstructed signal Calculate the amplitude corresponding to the frequency of rotation, and then calculate the envelope spectrum eigenvalues ​​based on the amplitude corresponding to the frequency of rotation.

[0060] Preferably, the method for calculating the bearing fault diagnosis standard threshold is as follows:

[0061] Impact enhancement reconstructed signal after matching pursuit denoising Hilbert envelope demodulation was performed to obtain the envelope spectrum signal. The peak energy value at the characteristic frequency of bearing failure is calculated and standardized to serve as a characteristic indicator for measuring the degree of bearing failure.

[0062] After standardizing the peak energy value at the characteristic frequency of bearing failure, the absolute energy value of the envelope spectrum, the characteristic value of the envelope spectrum, and the quantitative diagnostic threshold are obtained.

[0063] The method for obtaining the absolute energy value of the envelope spectrum is as follows:

[0064] The impact pulse method represents the fault impact energy by the impact amplitude in the time-domain waveform; according to the Parseval theorem, the energy of a signal has the equivalence in the time domain and the frequency domain; therefore, the sum of the amplitudes at the fault characteristic frequency and its harmonics in the envelope spectrum is used as the representation of the absolute energy value of the envelope spectrum, namely:

[0065] (1)

[0066] wherein, is the fault characteristic frequency of the envelope spectrum and the sum of the peak energy values at the Mth harmonic thereof, represents the corresponding amplitude at the frequency in the envelope spectrum of the signal.

[0067] Preferably, the envelope spectrum characteristic value is obtained by the following method:

[0068] Under different rotating speeds and load conditions, the amplitudes in the envelope spectrum of the signal will change significantly, resulting in a significant difference in the calculated peak energy value, and it is difficult to use a unified standard to evaluate the bearing fault degree; therefore, the amplitude corresponding to the amplitude of the rotational frequency component in the original signal spectrum is used as a measure of the rotating speed and the load, the peak energy value of the envelope spectrum is standardized, and then converted into a dB value, and finally the average of the energy peak values at the various fault characteristic frequencies and their harmonics is calculated as the final envelope spectrum characteristic value.

[0069] Preferably, the envelope spectrum characteristic value is calculated by the following formula:

[0070] (2)

[0071] wherein, represents the normalized energy value at each frequency in the envelope spectrum of the signal, in dB, represents the corresponding amplitude at the frequency in the original signal spectrum, represents the rotational frequency;

[0072] (3)

[0073] wherein, represents the envelope spectrum characteristic value of the fault characteristic frequency .

[0074] Preferably, the quantitative diagnosis threshold is obtained by the following method:

[0075] The envelope spectrum characteristic values corresponding to the four fault characteristic frequencies are calculated, and the maximum value among them is selected as the envelope spectrum characteristic value; the set fault determination threshold is an empirical value.

[0076] The fault determination relationship is:​​​

[0077] (4)

[0078] In the formula, represents the maximum value of the set R, R is the set of envelope spectrum characteristic values; is the fault determination threshold.

[0079] If the above formula is satisfied, it indicates that the bearing has a fault, and the fault type is determined according to the frequency of the characteristic value.

[0080] In a specific example, for the bearing outer ring:

[0081] Referring to Figure 2 , the alarm threshold of the bearing outer ring fault measuring point 1 of 209 is 45dB, and the diagnosis accuracy is 100%.

[0082] Referring to Figure 3 , the alarm threshold of the bearing outer ring fault measuring point 3 of 209 is 35dB, and the diagnosis accuracy is 99%.

[0083] Referring to Figure 4 , the alarm threshold of the bearing outer ring fault measuring point 8 of 209 is 37dB, and the diagnosis accuracy is 99%.

[0084] For the bearing inner ring:

[0085] Referring to Figure 5 , the alarm threshold of the bearing inner ring fault measuring point 1 of 209 is 47dB, and the diagnosis accuracy is 100%.

[0086] Referring to Figure 6 , the alarm threshold of the bearing inner ring fault measuring point 3 of 209 is 42dB, and the diagnosis accuracy is 95%.

[0087] Referring to Figure 7 , the alarm threshold of the bearing inner ring fault measuring point 8 of 209 is 32dB, and the diagnosis accuracy is 94%.

[0088] For the rolling body:

[0089] Referring to Figure 8 , the alarm threshold of the bearing rolling body fault measuring point 1 of 209 is 53dB, and the diagnosis accuracy is 94%.

[0090] Referring to Figure 9 , the alarm threshold of the bearing rolling body fault measuring point 3 of 209 is 40dB, and the diagnosis accuracy is 92%.

[0091] Referring to Figure 10 , the alarm threshold of the bearing rolling body fault measuring point 8 of 209 is 30dB, and the diagnosis accuracy is 89%.

[0092] Step S300, envelope spectrum characteristic value data of preset fault test is acquired, envelope spectrum characteristic values of different faults and different measuring points are comprehensively analyzed, and a comprehensive early warning diagnosis relationship is established.

[0093] Specifically, envelope spectrum characteristic value data of preset fault test is acquired, a Protugram algorithm based on improved weighted kurtosis value is used to select a filter frequency band, envelope spectrum is calculated after filtering and noise reduction, and fault characteristic frequency and multiple frequency amplitude in the envelope spectrum are extracted; 1X rotation frequency corresponding amplitude is calculated from the original signal speed spectrum; then, envelope spectrum characteristic values of different faults and different measuring points are calculated based on the 1X rotation frequency corresponding amplitude; different early warning diagnosis thresholds are set for different faults and different measuring points, and a comprehensive early warning diagnosis relationship is established based on the envelope spectrum characteristic values of different faults and different measuring points and the early warning diagnosis thresholds. The calculation method of the early warning diagnosis threshold is the same as that of the quantitative diagnosis threshold.

[0094] In one specific example, the early warning diagnosis threshold is set as follows:

[0095] The accuracy rates of measuring points 1, 3 and 8 for different fault types of the inner ring, the outer ring and the rolling element are shown in Table 1. The bearing fault alarm thresholds corresponding to the measuring points 1, 3 and 8 are shown in Table 2.

[0096] Table 1: Accuracy rate of 209 bearing typical fault diagnosis

[0097]

[0098] Table 2: 209 bearing fault early warning diagnosis threshold

[0099]

[0100] Step S400, envelope spectrum characteristic value data of failure fault test is acquired, envelope spectrum characteristic values of different faults and different measuring points are comprehensively analyzed, and a comprehensive failure diagnosis standard is established; then, a failure standard threshold is set to establish a failure diagnosis relationship.

[0101] Specifically, based on the failure standard threshold, failure diagnosis standards for different fault types of the inner ring, the outer ring and the rolling element are established; different failure standard thresholds are set for the measuring points selected after optimization analysis. The failure diagnosis standards and the failure standard thresholds are used to obtain a failure diagnosis relationship, and the corresponding bearing failure is judged when the failure diagnosis standard exceeds the failure standard threshold. The calculation method of the failure standard threshold is the same as that of the quantitative diagnosis threshold.

[0102] Preferably, in order to ensure sufficient failure redundancy, envelope spectrum characteristic values about 2 hours before the end of the test are used as the failure diagnosis standards; and the minimum values of each measuring point under different faults are used as the failure standard thresholds.

[0103] In one embodiment, the setting of the failure criterion threshold value is for the failure of the outer ring:

[0104] Since the measuring points 1, 3 and 8 can effectively diagnose the failure, it is suggested that the measuring points be arranged at the above-mentioned positions in actual application, and the failure threshold values are established for the measuring points respectively. The envelope spectrum characteristic value is used as an index, and smoothing filtering is performed to establish the failure threshold value. The failure curve is as shown in the following figure: Figures 11-13 As shown in the figure, in order to ensure sufficient failure redundancy, the index value at about 2 hours from the end of the failure test is taken as the standard value, and the index value at 1000s is counted here. The measuring point 1 is 71, the measuring point 3 is 60, and the measuring point 8 is 58.

[0105] For the failure of the inner ring:

[0106] Since the measuring points 1, 3 and 8 can effectively diagnose the failure, it is suggested that the measuring points be arranged at the above-mentioned positions in actual application, and the failure threshold values are established for the measuring points respectively. The envelope spectrum characteristic value is used as an index, and smoothing filtering is performed to establish the failure threshold value. The failure curve is as shown in the following figure: Figures 14-16 As shown in the figure, in order to ensure sufficient failure redundancy, the index value at about 2 hours from the end of the failure test is taken as the standard value, and the index value at 1000s is counted here. The measuring point 1 is 71, the measuring point 3 is 60, and the measuring point 8 is 58.

[0107] For the failure of the rolling element:

[0108] Since the measuring points 1, 3 and 8 can effectively diagnose the failure, it is suggested that the measuring points be arranged at the above-mentioned positions in actual application, and the failure threshold values are established for the measuring points respectively. The envelope spectrum characteristic value is used as an index, and smoothing filtering is performed to establish the failure threshold value. The failure curve is as shown in the following figure: Figures 17-19 As shown in the figure, in order to ensure sufficient failure redundancy, the index value at about 2 hours from the end of the failure test is taken as the standard value, and the index value at 1000s is counted here. The measuring point 1 is 71, the measuring point 3 is 60, and the measuring point 8 is 58.

[0109] Failure diagnosis criterion for failure of the engine housing:

[0110] In order to ensure sufficient failure redundancy, the envelope spectrum characteristic value at about 2 hours from the end of the test is taken as the failure diagnosis criterion. The failure diagnosis criterion is established for different failure types of the inner ring, the outer ring and the rolling element respectively, and the failure standard threshold values are established for the measuring points 1, 3 and 8 selected after optimization analysis of the measuring points.

[0111] As shown in the following table:

[0112] Table 3: Envelope spectrum characteristic value calculation result (dB)

[0113]

[0114] The minimum value of each measuring point under different faults is taken as the failure standard threshold, so the standard threshold of measuring point 1 is selected as 55 dB, the standard threshold of measuring point 3 is selected as 50 dB, and the standard threshold of measuring point 8 is selected as 43 dB.

[0115] To sum up, the inner ring, outer ring and rolling element bearing fault simulation tests are carried out respectively; the Protugram algorithm based on the improved weighted kurtosis value is used to select the filter frequency band, the envelope spectrum is extracted after filtering and noise reduction, and the bearing fault diagnosis standard threshold is established based on the envelope spectrum characteristic value method; based on the preset fault test, the envelope spectrum characteristic values of different faults and different measuring points are comprehensively analyzed, and the comprehensive early warning diagnosis standard is established; based on the failure fault test, the envelope spectrum characteristic values of different faults and different measuring points are comprehensively analyzed, and the comprehensive failure diagnosis standard is established.

[0116] First, the fault simulation test is used to establish the diagnosis standard under different faults, after judging that the bearing has no fault, the preset fault test and the failure fault test are carried out respectively, and the early warning diagnosis threshold and the failure standard threshold are established for the measuring points sensitive to the fault characteristics based on the optimization analysis of the measuring points, so as to realize the early warning and failure judgment of the bearing fault.

[0117] Finally, it should be noted that: the drawings of the disclosed embodiments of the application only involve the structures involved in the disclosed embodiments of the application, other structures can refer to the usual design, and under the condition of no conflict, the same embodiment and different embodiments of the application can be combined with each other;

[0118] Finally: the above only describes the preferred embodiments of the application and does not limit the application, any modification, equivalent replacement, improvement, etc. within the spirit and principles of the application should be included in the protection scope of the application.

Claims

1. A method for constructing a comprehensive diagnosis criterion of weak fault of typical small bearing, characterized in that, The application relates to a bearing fault diagnosis method based on envelope spectrum characteristic value. The application comprises the following steps: The Protugram algorithm based on the improved weighted kurtosis value is used to select the filter frequency band corresponding to different test data to filter and denoise, and to obtain the impact enhanced reconstruction signal The envelope spectrum is extracted after filtering and denoising, and envelope demodulation is performed to obtain the envelope spectrum absolute energy value, envelope spectrum characteristic value and quantitative diagnosis threshold value, respectively. Carrying out inner ring, outer ring and rolling element bearing fault simulation tests to obtain corresponding test data; Establishing a fault judgment relationship formula based on a quantitative diagnosis threshold value; when the fault judgment relationship formula judges that the bearing is fault-free, carrying out preset fault tests and failure fault tests; Obtaining envelope spectrum characteristic value data of the preset fault tests, comprehensively analyzing envelope spectrum characteristic values of different faults and different measuring points, and establishing a comprehensive early warning diagnosis relationship formula; 2. The method of claim 1, wherein the method is characterized by: The method of envelope demodulation is: calculating the amplitude value of the fault characteristic frequency and its multiple frequency in the envelope spectrum; on this basis, the impact value is quantified to obtain the impact enhanced reconstruction signal ; and based on the impact enhanced reconstruction signal , the amplitude value corresponding to the rotation frequency is calculated, and then the envelope spectrum characteristic value is calculated based on the amplitude value corresponding to the rotation frequency.

3. The method for constructing a comprehensive diagnostic standard for typical small bearing minor faults as described in claim 2, characterized in that: Obtaining envelope spectrum characteristic value data of the failure fault tests, comprehensively analyzing envelope spectrum characteristic values of different faults and different measuring points, and establishing a comprehensive failure diagnosis standard; then setting a failure standard threshold value to establish a failure diagnosis relationship formula. Impact enhanced reconstructed signal after matched pursuit denoising Hilbert envelope demodulation is performed to obtain an envelope spectrum signal The peak energy value at the bearing fault characteristic frequency is calculated and normalized as a characteristic index for measuring the bearing fault degree. The method for calculating the bearing fault diagnosis standard threshold value is as follows:

4. The method of claim 3, wherein the method further comprises: determining the weak fault diagnosis standard of the typical small bearing according to the weak fault diagnosis standard of the typical small bearing and the weak fault diagnosis standard of the typical small bearing. The peak energy value of the bearing fault characteristic frequency is standardized to obtain the envelope spectrum absolute energy value, the envelope spectrum characteristic value and the quantitative diagnosis threshold value. The impulse pulse method represents the fault impulse energy by the impact amplitude in the time domain waveform; according to the Parseval theorem, the energy of the signal has the equivalence of the time domain and the frequency domain; therefore, the sum of the amplitudes at the fault characteristic frequency and its harmonics in the envelope spectrum is used as the representation of the absolute energy value of the envelope spectrum, that is: ​ ； In the formula, The sum of the peak energy values at the envelope spectrum fault feature frequency and its Mth harmonic, represents the corresponding amplitude value of the signal envelope spectrum at the frequency frequency.

5. The method for constructing a comprehensive diagnostic standard for typical small bearing minor faults as described in claim 4, characterized in that: The envelope spectrum absolute energy value is obtained by the following method: The envelope spectrum characteristic value is obtained by the following method: the amplitude of the original signal frequency spectrum is taken as a measure of the rotation speed and the load, the envelope spectrum peak energy value is standardized, the unit is converted into a dB value, and finally the average of the energy peak values of various fault characteristic frequencies and their harmonics is taken as the final envelope spectrum characteristic value; ； In the formula, represents the normalized energy value at each frequency in the signal envelope spectrum, unit dB, represents the corresponding amplitude value of the original signal spectrum at the frequency, frequency, represents the frequency conversion; ； wherein represents the envelope spectrum characteristic value of the fault characteristic frequency .

6. The method for constructing a comprehensive diagnostic standard for typical small bearing minor faults as described in claim 5, characterized in that: The envelope spectrum characteristic value calculation formula is as follows: The quantitative diagnosis threshold value is obtained by the following method: The maximum value of the envelope spectrum characteristic values corresponding to the four fault characteristic frequencies is selected as the envelope spectrum characteristic value; The set fault judgment threshold value is an empirical value; ； In the formula, represents the element with the maximum value in the set R, R being the set of envelope spectrum characteristic values; is a fault determination threshold value; The fault judgment relationship formula is as follows:

7. The method for constructing a comprehensive diagnostic standard for typical small bearing minor faults as described in claim 1, characterized in that: If the above formula is met, it indicates that the bearing has a fault. The envelope spectrum characteristic value data of the preset fault tests are obtained, the Protugram algorithm based on the improved weighted kurtosis value is adopted to select a filter frequency band, the envelope spectrum is calculated after filter denoising, the fault characteristic frequency and the multiple frequency amplitude in the envelope spectrum are extracted, the 1X rotation frequency corresponding amplitude is obtained by calculating the original signal speed spectrum, and then the envelope spectrum characteristic values of different faults and different measuring points are calculated based on the 1X rotation frequency corresponding amplitude; 8. The method of claim 1, wherein the typical small bearing weak fault comprehensive diagnosis criterion is constructed by the following steps: 1) collecting the weak fault vibration signals of the typical small bearings; 2) extracting the weak fault feature parameters of the typical small bearings; 3) establishing the weak fault comprehensive diagnosis criterion of the typical small bearings. Different early warning diagnosis threshold values are set for different faults and different measuring points, and the comprehensive early warning diagnosis relationship formula is established based on the envelope spectrum characteristic values of different faults and different measuring points and the early warning diagnosis threshold values.

9. The method for constructing a comprehensive diagnostic standard for typical small bearing minor faults as described in claim 8, characterized in that: The failure diagnosis standards of different fault types of the inner ring, the outer ring and the rolling element are established based on the failure standard threshold value; different failure standard threshold values are set for the selected measuring points after optimization analysis of the measuring points; the failure diagnosis relationship formula is obtained by combining the failure diagnosis standards and the failure standard threshold values, and the corresponding bearing failure is judged when the failure diagnosis standard exceeds the failure standard threshold value. The envelope spectrum characteristic value about 2 hours before the test ends is taken as the failure diagnosis standard, and the minimum value of each measuring point under different faults is taken as the failure standard threshold value.

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