Bearing fault judgment method, electric drive assembly and storage medium

Abstract

The invention discloses a bearing fault judgment method, an electric drive assembly and a storage medium, and relates to the technical field of vehicles, and the bearing fault judgment method comprises the steps that a data acquisition unit is installed on a circuit board where an electric drive control system is located, and a rotating speed signal and a sound signal which are collected in real time based on the data acquisition unit are calculated through a preset fault judgment threshold calculation method; converting into a target relational graph between sound amplitude and sound frequency under each motor rotating speed, calculating on the target relational graph to obtain a bearing fault order, performing order slicing on the target relational graph according to the bearing fault order to obtain a target bearing fault order corresponding to the target frequency multiplication, and calculating the bearing fault order according to the target bearing fault order. And obtaining a target fault judgment threshold based on each target bearing fault order, selecting a preset judgment threshold corresponding to the preset fault judgment threshold calculation method, comparing the preset judgment threshold with the target fault judgment threshold, and determining whether the bearing is in a fault state or not according to a comparison result, thereby solving the problem of low bearing fault detection accuracy.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a bearing fault judgment method, an electric drive assembly and a storage medium. Background Art

[0002] Bearings are the basis of vehicle transmission components and an important part of the vehicle electric drive assembly system. They are used to support the shaft and help the shaft rotate. They have a significant impact on the function and performance of the electric drive assembly. Therefore, bearing fault detection for the electric drive assembly is particularly important. Usually, the vehicle voice system is used to receive the electric drive sound transmitted to the vehicle. After envelope, FFT and other processing, the bearing fundamental frequency order slice is extracted and compared with a specific threshold to determine whether the bearing is faulty. However, this solution has problems with inaccurate fault detection and high delay in detection results in actual applications.

[0003] The conventional comparison logic is to compare the RMS value of the order slice of the envelope data colormap with a specific threshold to determine whether the electric drive bearing is faulty. However, considering the influence of interference such as working conditions, road conditions, and environmental noise, using an immutable specific threshold as the comparison object may result in judgment errors. At the same time, because the electric drive bearing is a chassis component of the vehicle, it is located in a different compartment of the vehicle from the on-board language system. When the abnormal sound level of the electric drive bearing is low, the abnormal sound cannot break through the acoustic envelope of the entire vehicle and be recognized by the on-board language system. When the abnormal sound level of the electric drive bearing is high, it means that the fault of the electric drive bearing has lasted for a long time. The time from the abnormal sound of the electric drive bearing to the detection of the abnormal sound is too long, resulting in a slow processing speed for the bearing fault.

[0004] Therefore, it is believed that the conventional bearing fault judgment scheme has the problems of low electric drive bearing fault detection accuracy and high detection result delay, and cannot timely and effectively judge the electric drive bearing fault to ensure the safe and reliable operation of the vehicle. Summary of the invention

[0005] The main purpose of the present application is to provide a bearing fault judgment method, an electric drive assembly and a storage medium, aiming to solve the technical problems of low bearing fault detection accuracy and high detection result delay in conventional bearing fault judgment schemes.

[0006] To achieve the above purpose, the present application proposes a bearing fault judgment method, which is applied to an electric drive assembly, wherein the electric drive assembly includes an electric drive control system, and a data acquisition unit is installed on a circuit board where the electric drive control system is located. The bearing fault judgment method includes:

[0007] By using a preset fault judgment threshold calculation method, the speed signal and sound signal collected in real time by the data acquisition unit are converted into a target relationship diagram between the sound amplitude and the sound frequency at each motor speed, wherein the speed signal is the motor speed of the bearing in a preset period of time, and the sound signal is the sound amplitude and sound frequency generated when the bearing vibrates in the preset period of time;

[0008] The bearing fault order is calculated on the target relationship diagram, and the target relationship diagram is sliced ​​according to the bearing fault order. After the target bearing fault order corresponding to the target frequency multiplication is obtained, the target fault judgment threshold is obtained based on each target bearing fault order.

[0009] A preset judgment threshold corresponding to the preset fault judgment threshold calculation method is selected, and compared with the target fault judgment threshold, and based on the comparison result, it is determined whether the bearing is in a fault state.

[0010] In one embodiment, before the step of converting the speed signal and the sound signal collected in real time by the data acquisition unit into a target relationship diagram between the sound amplitude and the sound frequency at each motor speed by a preset fault judgment threshold calculation method, the step also includes:

[0011] The data acquisition unit is used to collect in real time the initial speed signal and the initial sound signal during the transition period when the rotation speed of the bearing changes while the vehicle is in a driving state;

[0012] Based on a preset time period, an initial speed signal and an initial sound signal are intercepted to generate an audio file in a preset format, wherein the audio file includes a speed signal and a sound signal in a preset time period; and, based on the motor speed and the motor speed difference at any time point in the transition period of the initial speed signal, when the motor speed is greater than the preset motor speed or the motor speed difference is greater than the preset motor speed difference, a bearing fault judgment state is entered, and a preset fault judgment threshold calculation method is executed to convert the speed signal and the sound signal collected in real time by the data acquisition unit into a target relationship diagram between the sound amplitude and the sound frequency at each motor speed.

[0013] In one embodiment, when the preset fault judgment threshold value calculation method called is the first fault judgment threshold value calculation method or the second fault judgment threshold value calculation method, the step of converting the speed signal and the sound signal collected in real time by the data acquisition unit into a target relationship diagram between the sound amplitude and the sound frequency at each motor speed by the preset fault judgment threshold value calculation method includes:

[0014] Based on the first fault judgment threshold calculation method or the second fault judgment threshold calculation method, the audio file is converted into a target relationship diagram between the sound amplitude and the sound frequency at each motor speed.

[0015] In one embodiment, the bearing fault order is calculated on the target relationship graph, and the target relationship graph is sliced ​​according to the bearing fault order to obtain the target bearing fault order corresponding to the target frequency multiplication. The step of obtaining the target fault judgment threshold based on each target bearing fault order includes:

[0016] Substitute the geometric parameters of the bearing into the calculation formula of the bearing fault frequency, calculate the bearing fault order of 1 times the frequency, and then multiply the bearing fault order of 1 times the frequency by other continuous times in sequence to obtain multiple bearing fault orders of different times;

[0017] According to the bearing fault orders corresponding to each preset integer multiple frequency in the preset multiple frequency interval, the target relationship diagram is sliced ​​by order to obtain a first target bearing fault order, and based on the bearing fault order corresponding to the preset decimal multiple frequency, the target relationship diagram is sliced ​​by order to obtain a second target bearing fault order, wherein the target multiple frequency includes a preset integer multiple frequency and a preset decimal multiple frequency, and the target bearing fault order includes a first target bearing fault order and a second target bearing fault order;

[0018] Calculate the first root mean square value of the slice curve of each first target bearing fault order and the second root mean square value of the slice curve of each second target bearing fault order, and obtain the target fault judgment threshold based on each first root mean square value and each second root mean square value.

[0019] In one embodiment, when the preset fault judgment threshold calculation method called is the first fault judgment threshold calculation method, the step of obtaining the target fault judgment threshold based on each first root mean square value and each second root mean square value includes:

[0020] After adding the first root mean square values ​​to obtain a first sum value and adding the second root mean square values ​​to obtain a second sum value, the second sum value is subtracted from the first sum value to obtain a target fault judgment threshold value;

[0021] The steps of selecting a preset judgment threshold corresponding to the preset fault judgment threshold calculation method, comparing it with the target fault judgment threshold, and determining whether the bearing is in a fault state according to the comparison result include:

[0022] Determine a first preset judgment threshold corresponding to the first fault judgment threshold calculation method, and obtain a comparison result between the target fault judgment threshold and the first preset judgment threshold, wherein the first preset judgment threshold is a lower limit difference of a bearing fault;

[0023] If the comparison result is that the target fault judgment threshold is equal to or greater than the first preset judgment threshold, it is determined that the bearing is in a fault state;

[0024] If the comparison result is that the target fault judgment threshold is less than the first preset judgment threshold, it is determined that the bearing is not in a fault state.

[0025] In one embodiment, when the preset fault judgment threshold calculation method called is the second fault judgment threshold calculation method, the step of obtaining the target fault judgment threshold based on each first root mean square value and each second root mean square value includes:

[0026] According to the correspondence between each preset integer multiple frequency and each decimal multiple frequency, obtaining the difference between each first root mean square value and the second root mean square value corresponding to each first root mean square value;

[0027] Counting the number of differences greater than a first preset judgment threshold, and determining the number of differences as a target fault judgment threshold, wherein the first preset judgment threshold is a lower limit difference for bearing faults;

[0028] The steps of selecting a preset judgment threshold corresponding to the preset fault judgment threshold calculation method, comparing it with the target fault judgment threshold, and determining whether the bearing is in a fault state according to the comparison result include:

[0029] Determine a second preset judgment threshold corresponding to the second fault judgment threshold calculation method, and obtain a comparison result between the target fault judgment threshold and the second preset judgment threshold, wherein the second preset judgment threshold is a lower limit number threshold of bearing faults;

[0030] If the comparison result is that the target fault judgment threshold is equal to or greater than the second preset judgment threshold, it is determined that the bearing is in a fault state;

[0031] If the comparison result is that the target fault judgment threshold is less than the second preset judgment threshold, it is determined that the bearing is not in a fault state.

[0032] In one embodiment, when the preset fault judgment threshold value calculation method called is the third fault judgment threshold value calculation method, the step of converting the speed signal and the sound signal collected in real time by the data acquisition unit into a target relationship diagram between the sound amplitude and the sound frequency at each motor speed by using the preset fault judgment threshold value calculation method includes:

[0033] Based on the third fault judgment threshold calculation method, the sound signal in the audio file is subjected to Hilbert transformation, and the envelope of the sound signal after Hilbert transformation is extracted to obtain an envelope signal of the sound signal;

[0034] The envelope signal and the speed signal in the audio file are converted into a target relationship diagram between the sound amplitude and the sound frequency at each motor speed.

[0035] In one embodiment, the bearing fault order is calculated on the target relationship graph, and the target relationship graph is sliced ​​according to the bearing fault order to obtain the target bearing fault order corresponding to the target frequency multiplication. The step of obtaining the target fault judgment threshold based on each target bearing fault order includes:

[0036] Substitute the geometric parameters of the bearing into the bearing fault frequency calculation formula, calculate the bearing fault order of 1 times the frequency, and obtain the third target bearing fault order;

[0037] Slicing the target relationship graph in order based on the preset frequency multiple to obtain a fourth target bearing fault order;

[0038] Calculate a third root mean square value corresponding to the slice curve sound pressure value of the third target bearing fault order, and a fourth root mean square value corresponding to the slice curve sound pressure value of the fourth target bearing fault order;

[0039] Determine a difference value obtained by subtracting the fourth root mean square value from the third root mean square value as a target fault judgment threshold;

[0040] The steps of selecting a preset judgment threshold corresponding to the preset fault judgment threshold calculation method, comparing it with the target fault judgment threshold, and determining whether the bearing is in a fault state according to the comparison result include:

[0041] Determine a third preset judgment threshold corresponding to the third fault judgment threshold calculation method, and obtain a comparison result between the target fault judgment threshold and the third preset judgment threshold, wherein the third preset judgment threshold is a lower limit value of a bearing fault;

[0042] If the comparison result is that the target fault judgment threshold is equal to or greater than the third preset judgment threshold, it is determined that the bearing is in a fault state;

[0043] If the comparison result is that the target fault judgment threshold is less than the third preset judgment threshold, it is determined that the bearing is not in a fault state.

[0044] In addition, to achieve the above objectives, the present application also proposes an electric drive assembly, which includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the bearing fault judgment method as described above.

[0045] In addition, to achieve the above-mentioned purpose, the present application also proposes a storage medium, which is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by the processor, the steps of the bearing fault judgment method described above are implemented.

[0046] One or more technical solutions proposed in this application have at least the following technical effects:

[0047] A bearing fault judgment method is proposed. The bearing fault judgment method is applied to an electric drive assembly. The electric drive assembly includes an electric drive control system. A data acquisition unit is installed on a circuit board where the electric drive control system is located. The bearing fault judgment method includes: converting a speed signal and a sound signal collected in real time by the data acquisition unit into a target relationship diagram between sound amplitude and sound frequency at each motor speed through a preset fault judgment threshold calculation method, wherein the speed signal is the motor speed of the bearing in a preset time period and the sound frequency corresponding to the motor speed, and the sound signal is the sound amplitude generated when the bearing vibrates in the preset time period; calculating the bearing fault order on the target relationship diagram, and order slicing the target relationship diagram according to the bearing fault order, and after obtaining the target bearing fault order corresponding to the target frequency multiplication, obtaining the target fault judgment threshold based on each target bearing fault order; selecting a preset judgment threshold corresponding to the preset fault judgment threshold calculation method, comparing it with the target fault judgment threshold, and determining whether the bearing is in a fault state based on the comparison result.

[0048] That is, the present application arranges a data acquisition unit for collecting the speed signal and sound signal of the bearing inside the electric drive assembly, and arranges it on the same circuit board as the electric drive control system, so that the data acquisition unit and the electric drive control system are in the same compartment, shortening the distance between the bearing and the data acquisition unit, thereby improving the accuracy and timeliness of the speed signal and sound signal collection. When there is a sound signal with a low degree of abnormal sound in the early stage, it can also be detected and collected by the data acquisition unit in time for bearing fault detection, avoiding the situation where the sound signal cannot be collected in the early stage and the detection result is delayed too much, resulting in reduced fault detection accuracy. The present application also sets up that the collected speed signal and sound signal are converted into a corresponding target relationship diagram through different preset fault judgment threshold calculation methods, so as to improve the efficiency of identifying the relationship between the sound amplitude and the sound frequency of the bearing at different motor speeds, improve the fault judgment efficiency, determine the bearing fault order on the target relationship diagram, and slice the target relationship diagram based on the bearing fault order, so that the obtained target bearing fault order is the frequency component related to the bearing fault, thereby reducing the adverse effects of interference information on the judgment accuracy, and then after obtaining the target fault judgment threshold based on each target bearing fault order, the preset judgment threshold corresponding to the preset fault judgment threshold calculation method is selected and compared with the target fault judgment threshold, and according to the comparison result, it is determined whether the bearing is When in a fault state, a target fault judgment threshold obtained by different preset fault judgment threshold calculation methods is set and compared with different preset judgment thresholds, so as to avoid the situation where only one bearing fault judgment result can be obtained based on a single fault judgment threshold calculation method, and the influence of interference such as working conditions, road conditions, and environmental noise cannot be considered. An immutable specific threshold is used as a comparison object, and there is a judgment error. The present application proposes to obtain one or more target fault judgment thresholds with different characteristics by calling one or more corresponding preset fault judgment threshold calculation methods, and select the preset judgment thresholds corresponding to the multiple called preset fault judgment threshold calculation methods for comparison, so as to judge a variety of bearing fault scenarios and enhance the accuracy and reliability of bearing fault judgment. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0050] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0051] Figure 1 A schematic diagram of a flow chart provided for an embodiment of a bearing fault determination method of the present application;

[0052] Figure 2 A schematic diagram of a transformation for performing Fourier transform on an audio file to obtain a second three-dimensional graph;

[0053] Figure 2 (1) is a first three-dimensional relationship diagram of the motor speed, the sound pressure value of the bearing noise and the sound frequency in the audio file;

[0054] Figure 2 (2) is a second three-dimensional relationship diagram of the corresponding relationship between the motor speed, the sound pressure value of the bearing noise and the sound frequency;

[0055] Figure 3 A schematic diagram of a transformation for projecting the second three-dimensional graph from top to bottom into a two-dimensional target relationship graph;

[0056] Figure 3 (1) is a second three-dimensional relationship diagram of the corresponding relationship between the motor speed, the sound pressure value of the bearing noise and the sound frequency;

[0057] Figure 3 (2) is a target relationship diagram obtained based on the first fault judgment threshold calculation method or converted by the first fault judgment threshold calculation method;

[0058] Figure 4 A schematic diagram of the corresponding relationship of the sound amplitude corresponding to the bearing fault order of the integer multiple frequency, obtained by plane-cutting the second three-dimensional graph with the bearing fault order of the integer multiple frequency;

[0059] Figure 4 (1) is a second three-dimensional relationship diagram of the corresponding relationship between the motor speed, the sound pressure value of the bearing noise and the sound frequency;

[0060] Figure 4 (2) is a schematic diagram of the corresponding relationship between the sound amplitude and the motor speed corresponding to the order slice of the bearing fault order 4.66;

[0061] Figure 5 This is a target relationship diagram obtained by conversion based on the third fault judgment threshold calculation method of the present application;

[0062] Figure 6 A brief flowchart of a bearing fault determination method according to an embodiment of the present application;

[0063] Figure 7 Schematic diagram of the equipment structure of the hardware operating environment involved in the bearing fault judgment method in the embodiment of the present application.

[0064] The purpose, features and advantages of this application will be further described in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0065] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and are not used to limit the present application.

[0066] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0067] The main solution of the embodiment of the present application is: by installing the data acquisition unit on the circuit board where the electric drive control system is located, and by using a preset fault judgment threshold calculation method, the speed signal and sound signal collected in real time by the data acquisition unit are converted into a target relationship diagram between sound amplitude and sound frequency at each motor speed, wherein the speed signal is the motor speed of the bearing in a preset time period, and the sound signal is the sound amplitude and sound frequency generated when the bearing vibrates in a preset time period. The bearing fault order is calculated on the target relationship diagram, and the target relationship diagram is sliced ​​according to the bearing fault order. After obtaining the target bearing fault order corresponding to the target frequency multiplication, the target fault judgment threshold is obtained based on each target bearing fault order, the preset judgment threshold corresponding to the preset fault judgment threshold calculation method is selected, and compared with the target fault judgment threshold, and based on the comparison result, it is determined whether the bearing is in a fault state.

[0068] Since the vehicle voice system is usually used to receive the electric drive sound transmitted to the vehicle, after envelope, FFT and other processing, the bearing fundamental frequency order slice is extracted and compared with the specific threshold to determine whether the bearing is faulty. However, this solution has the problems of inaccurate fault detection and high delay in detection results in actual applications. The conventional comparison logic is to compare the RMS value of the order slice of the envelope data colormap with the specific threshold to determine whether the electric drive bearing is faulty. However, considering the influence of interference such as working conditions, road conditions, and environmental noise, the immutable specific threshold is used as the comparison object, and there is a judgment error. At the same time, because the electric drive bearing belongs to the chassis component of the vehicle, it is located in different compartments of the vehicle with the vehicle language system. When the abnormal sound level of the electric drive bearing is low, the abnormal sound cannot break through the acoustic envelope of the whole vehicle and be recognized by the vehicle language system. When the abnormal sound level of the electric drive bearing is high, it means that the fault of the electric drive bearing has lasted for a long time. The time from the abnormal sound of the electric drive bearing to the detection of the abnormal sound is too long, resulting in a slow processing speed for the bearing fault.

[0069] Therefore, it is believed that the conventional bearing fault judgment scheme has the problems of low electric drive bearing fault detection accuracy and high detection result delay, and cannot timely and effectively judge the electric drive bearing fault to ensure the safe and reliable operation of the vehicle.

[0070] The present application provides a solution, by arranging a data acquisition unit for collecting the speed signal and sound signal of the bearing inside the electric drive assembly, and arranging it on the same circuit board as the electric drive control system, so that the data acquisition unit and the electric drive control system are in the same compartment, and the distance between them and the bearing is shortened, thereby improving the accuracy and timeliness of the speed signal and sound signal acquisition, and enabling the data acquisition unit to detect and collect the sound signal in time when there is a sound signal with a low degree of abnormal sound in the early stage for bearing fault detection, thereby avoiding the situation where the sound signal cannot be collected in the early stage and the detection result is delayed too much, resulting in reduced fault detection accuracy. The present application also sets up that the collected speed signal and sound signal are converted into a corresponding target relationship diagram through different preset fault judgment threshold calculation methods, so as to improve the efficiency of identifying the relationship between the sound amplitude and the sound frequency of the bearing at different motor speeds, improve the fault judgment efficiency, determine the bearing fault order on the target relationship diagram, and slice the target relationship diagram based on the bearing fault order, so that the obtained target bearing fault order is the frequency component related to the bearing fault, thereby reducing the adverse effects of interference information on the judgment accuracy, and then after obtaining the target fault judgment threshold based on each target bearing fault order, the preset judgment threshold corresponding to the preset fault judgment threshold calculation method is selected and compared with the target fault judgment threshold, and according to the comparison result, it is determined whether the bearing is When in a fault state, a target fault judgment threshold obtained by different preset fault judgment threshold calculation methods is set and compared with different preset judgment thresholds, so as to avoid the situation where only one bearing fault judgment result can be obtained based on a single fault judgment threshold calculation method, and the influence of interference such as working conditions, road conditions, and environmental noise cannot be considered. An immutable specific threshold is used as a comparison object, and there is a judgment error. The present application proposes to obtain one or more target fault judgment thresholds with different characteristics by calling one or more corresponding preset fault judgment threshold calculation methods, and select the preset judgment thresholds corresponding to the multiple called preset fault judgment threshold calculation methods for comparison, so as to judge a variety of bearing fault scenarios and enhance the accuracy and reliability of bearing fault judgment.

[0071] It should be noted that the execution subject of this embodiment can be a computing service device with data processing, network communication and program running functions, such as a tablet computer, a personal computer, a mobile phone, etc., or an electronic device, a terminal device, etc. that can realize the above functions. The following takes the electric drive assembly as an example to illustrate this embodiment and the following embodiments.

[0072] Based on this, the embodiment of the present application provides a bearing fault judgment method, referring to Figure 1 , Figure 1 This is a flow chart of the first embodiment of the bearing fault judgment method of the present application.

[0073] In this embodiment, the bearing fault judgment method includes steps S10 to S30:

[0074] Step S10, through a preset fault judgment threshold calculation method, converts the speed signal and sound signal collected in real time by the data acquisition unit into a target relationship diagram between the sound amplitude and the sound frequency at each motor speed, wherein the speed signal is the motor speed of the bearing in a preset time period, and the sound signal is the sound amplitude and sound frequency generated when the bearing vibrates in a preset time period.

[0075] It should be noted that in order to be able to detect the minor faults of the early bearings in time and to repair the minor faults in time, the problem of inaccurate bearing fault detection caused by the omission of minor faults of the early bearings, as well as the problem of high delay in detection results and increased bearing faults caused by the detection errors of minor faults, can be avoided. This embodiment proposes to install the data acquisition unit for collecting information related to bearing faults on the circuit board where the electric drive control system is located. Because the electric drive bearing (hereinafter referred to as the bearing) is included in the electric drive control system, the data acquisition unit installed on the corresponding circuit board can effectively collect the sound signal generated by the rotation of the bearing in time, so as to prevent the early minor faults of the bearing in time. At the same time, because the data acquisition unit is directly installed on the circuit board, the wiring operation is avoided, the installation process is more convenient and the installation cost is also relatively low.

[0076] That is, this embodiment arranges the data acquisition unit and the bearing in the same space to avoid the situation where the slight abnormal noise caused by a slight fault cannot be detected by the data acquisition unit due to the difference in space. Therefore, in the design process of the electric drive assembly, a certain space will be reserved on the circuit board where the electric drive assembly is located for the installation of the data acquisition unit. Compared with the conventional operation of collecting abnormal noises of bearing faults based on the vehicle-mounted language system, this application can prevent the abnormal noises of bearing faults from being transmitted to the space where the user is located, causing the user to feel worried and uneasy after hearing the abnormal noises of the bearing faults.

[0077] Among them, the sound amplitude in this embodiment is the audio amplitude or the vibration amplitude. When the data acquisition unit is an audio mic sensor, the sound signal is the audio amplitude and audio frequency generated when the bearing vibrates over a preset time period; when the data acquisition unit is a vibration sensor, the sound signal is the vibration amplitude and vibration frequency generated when the bearing vibrates over a preset time period.

[0078] The preset fault threshold judgment method is set based on different bearing fault judgment characteristics. This embodiment sets three preset fault threshold judgment methods. Based on actual judgment needs, the three preset fault threshold judgment methods can be dynamically selected and combined to judge the bearing faults in different bearing fault scenarios, thereby avoiding the low reference value caused by only judging the bearing fault through a single bearing fault scenario. When there is interference item information in the bearing fault scenario, the accuracy of the obtained bearing fault judgment result is reduced.

[0079] Specifically, after entering the bearing fault judgment state, the corresponding preset fault threshold judgment method will be called to first process the speed signal and sound signal collected by the data acquisition unit, and convert them into a target relationship diagram that can conveniently diagnose and locate the bearing fault. Mainly, the motor speed in the speed signal and the sound amplitude and sound frequency in the sound signal are processed accordingly, and then converted into a target relationship diagram that can reflect the sound amplitude and sound frequency corresponding to the motor speed at multiple moments, thereby improving the recognition efficiency of the corresponding relationship between the motor speed, sound frequency and sound amplitude.

[0080] Among them, the preset time period is set based on actual judgment needs. Since the data acquisition unit collects the speed signal and the sound signal in real time, in order to avoid the problem of excessive data calculation and processing due to too many speed signals and sound signals currently collected in real time, this embodiment sets a preset time period for intercepting the speed signal and the sound signal.

[0081] It should be noted that the speed signal and the sound signal intercepted according to the preset time period are signals collected in the same time period.

[0082] In a feasible implementation manner, step S10 may include steps S11 to S13:

[0083] Step S11, collecting in real time, through a data collection unit, an initial speed signal and an initial sound signal during a transition period when the rotation speed of the bearing changes while the vehicle is in a driving state.

[0084] Because the bearing fault of the electric drive assembly is to be judged, in order to reduce the system resources occupied by the real-time collection of relevant signals by the data acquisition unit, this embodiment proposes a method for reducing the occupied system resources, that is, when it is detected that the vehicle is in a driving state and the rotation speed of the bearing is in a preset rotation speed range, the signal related to the rotation speed of the bearing is started to be collected, and it is judged according to the signal that the rotation speed of the bearing has changed, then it is considered that the bearing may have a fault at this time, and therefore the data acquisition unit is controlled to collect in real time the initial speed signal and the initial sound signal during the period when the rotation speed of the bearing changes.

[0085] If it is determined based on the signal that the rotation speed of the bearing has not changed, or if the vehicle is not detected to be in a driving state, it is considered that the bearing is not faulty at this time and there is no need to collect relevant signals, thereby reducing the system resources occupied by the data acquisition unit.

[0086] It should be noted that the data acquisition unit needs to synchronously collect the initial speed signal and the initial sound signal, that is, the initial speed signal and the initial sound signal collected by the data acquisition unit in real time are in the same time period.

[0087] Step S12, intercepting the initial rotation speed signal and the initial sound signal based on a preset time period to generate an audio file in a preset format, wherein the audio file includes the rotation speed signal and the sound signal in the preset time period.

[0088] After collecting continuous initial speed signals and initial sound signals during the period when the rotation speed of the bearing changes, in order to reduce the subsequent data calculation processing volume, the initial speed signal and initial sound signal will be intercepted based on a preset time period to obtain a speed signal and sound signal of a shorter period, and the intercepted speed signal and sound signal will be converted into an audio file in a preset format.

[0089] Among them, the speed signal and the sound signal intercepted according to the preset time period in this embodiment are signals in the same time period, that is, the time point corresponding to the intercepted speed signal can correspond to the time point corresponding to the intercepted sound signal, so as to ensure the accuracy of fault judgment. It should also be noted that the preset format in this embodiment is ".wav", and in actual application scenarios, it can also be other digital audio formats.

[0090] Step S13, when the motor speed is greater than the preset motor speed or the motor speed difference is greater than the preset motor speed difference based on the motor speed and the motor speed difference of the initial speed signal at any time point in the transition period, the bearing fault judgment state is entered, and a preset fault judgment threshold calculation method is executed to convert the speed signal and sound signal collected in real time by the data acquisition unit into a target relationship diagram between the sound amplitude and the sound frequency at each motor speed.

[0091] Because the higher the motor speed of the bearing, the more obvious the bearing failure is, and the motor speed difference of the bearing can reflect the dynamic changes of the bearing. Therefore, after the initial speed signal is obtained in real time through the data acquisition unit, the motor speed and motor speed difference corresponding to the initial speed signal at any time point are obtained, and it is determined whether the obtained motor speed is greater than the preset motor speed, and whether the obtained motor speed difference is greater than the preset motor speed difference, that is, whether the motor speed and the motor speed difference at this time point have the risk of causing bearing failure, and then determine whether it is necessary to enter the bearing fault judgment state, and perform specific fault judgment on the bearing of the electric drive assembly, so as to further reduce the occupied system resources and avoid the invalid fault judgment caused by entering the bearing fault judgment state when there is no bearing failure risk, resulting in waste of system resources.

[0092] The preset motor speed and the preset motor speed difference are set based on actual judgment of the bearing operating parameters on the electric drive assembly. The preset motor speed and the preset motor speed difference set in this embodiment are both 2krpm (two thousand revolutions per minute).

[0093] Step S20, calculating the bearing fault order on the target relationship diagram, and slicing the target relationship diagram according to the bearing fault order, after obtaining the target bearing fault order corresponding to the target frequency multiplication, obtaining the target fault judgment threshold based on each target bearing fault order.

[0094] The bearing fault order appears as specific peaks on the target relationship diagram, and these peaks can indicate that the bearing is faulty. Therefore, by calculating the bearing fault order on the target relationship diagram, the possible bearing faults on the target relationship diagram can be predicted.

[0095] The frequency multiplication is used to confirm whether the calculated bearing fault order is caused by the bearing fault. Because the bearing vibration under normal conditions does not cause obvious frequency multiplication peaks, when an obvious frequency multiplication peak is obtained through the target relationship diagram, it means that the bearing fault order corresponding to the frequency multiplication peak is caused by the bearing fault.

[0096] Among them, according to the selected preset fault judgment threshold calculation method, a single or multiple bearing fault orders with different multiple frequencies are calculated. The reason for calculating multiple bearing fault orders with different multiple frequencies is that as the bearing fault worsens, the amplitude of the multiple frequencies will increase accordingly. Therefore, by calculating the bearing fault orders corresponding to multiple different multiple frequencies, the development trend of the bearing fault can be obtained, so that the subsequent bearing fault judgment can detect the bearing fault under different bearing fault development trends, thereby improving the reliability of the bearing fault judgment results.

[0097] After the bearing fault order is calculated, this embodiment proposes to slice the target relationship graph by the bearing fault order corresponding to the set frequency doubling, so as to extract the target bearing fault order with significant characteristics of the bearing fault, and ignore the influence of the order with interference properties on the bearing fault judgment result. At the same time, the order slicing operation of the target relationship graph can reduce the subsequent calculation amount, improve the efficiency of bearing fault judgment, and avoid the problem of excessive calculation amount when directly judging the bearing fault based on all the data in the entire target relationship graph.

[0098] The target bearing fault order corresponding to the target frequency multiplication obtained through the above steps can reflect the motor speed and sound frequency corresponding to the bearing fault characteristics in its sound amplitude when the bearing fails. Therefore, according to each target bearing fault order, the target fault judgment threshold used to measure the current bearing operating status can be calculated.

[0099] Step S30, selecting a preset judgment threshold corresponding to the preset fault judgment threshold calculation method, comparing it with the target fault judgment threshold, and determining whether the bearing is in a fault state based on the comparison result.

[0100] After the corresponding target fault judgment threshold is calculated through the above steps, the preset fault judgment threshold calculation method for calculating the target fault judgment threshold is used to select the preset judgment threshold corresponding to the preset fault judgment threshold calculation method, and the comparison result is able to reflect whether the bearing is in a fault state, that is, one or more target fault judgment thresholds with different characteristics are obtained by calling one or more corresponding preset fault judgment threshold calculation methods, and the preset judgment threshold corresponding to the called preset fault judgment threshold calculation method is selected for comparison, so as to judge various bearing fault scenarios and enhance the accuracy and reliability of bearing fault judgment.

[0101] In this embodiment, a data acquisition unit for collecting the speed signal and sound signal of the bearing is arranged inside the electric drive assembly and on the same circuit board as the electric drive control system, so that the data acquisition unit and the electric drive control system are in the same compartment and the distance between them and the bearing is shortened, thereby improving the accuracy and timeliness of the collection of the speed signal and the sound signal. Even when there is a sound signal with a low degree of abnormal sound in the early stage, it can be detected and collected by the data acquisition unit in time to detect the bearing fault, thereby avoiding the situation where the sound signal cannot be collected in the early stage and the detection result is delayed too much, resulting in reduced fault detection accuracy. The present application also sets up that the collected speed signal and sound signal are converted into a corresponding target relationship diagram through different preset fault judgment threshold calculation methods, so as to improve the efficiency of identifying the relationship between the sound amplitude and the sound frequency of the bearing at different motor speeds, improve the fault judgment efficiency, determine the bearing fault order on the target relationship diagram, and slice the target relationship diagram based on the bearing fault order, so that the obtained target bearing fault order is the frequency component related to the bearing fault, thereby reducing the adverse effects of interference information on the judgment accuracy, and then after obtaining the target fault judgment threshold based on each target bearing fault order, the preset judgment threshold corresponding to the preset fault judgment threshold calculation method is selected and compared with the target fault judgment threshold, and according to the comparison result, it is determined whether the bearing is When in a fault state, a target fault judgment threshold obtained by different preset fault judgment threshold calculation methods is set and compared with different preset judgment thresholds, so as to avoid the situation where only one bearing fault judgment result can be obtained based on a single fault judgment threshold calculation method, and the influence of interference such as working conditions, road conditions, and environmental noise cannot be considered. An immutable specific threshold is used as a comparison object, and there is a judgment error. The present application proposes to obtain one or more target fault judgment thresholds with different characteristics by calling one or more corresponding preset fault judgment threshold calculation methods, and select the preset judgment thresholds corresponding to the multiple called preset fault judgment threshold calculation methods for comparison, so as to judge a variety of bearing fault scenarios and enhance the accuracy and reliability of bearing fault judgment.

[0102] The following is a detailed description of the embodiments according to the three preset fault judgment threshold calculation methods proposed in this application.

[0103] In a first feasible implementation manner, when the preset fault judgment threshold calculation method is the first fault judgment threshold calculation method, the bearing fault judgment method includes steps A11 to A18:

[0104] Step A11, based on the first fault judgment threshold calculation method, convert the audio file into a target relationship diagram between the sound amplitude and the sound frequency at each motor speed.

[0105] by Figure 2 Take this as an example to illustrate: Figure 2(1) is the first three-dimensional relationship diagram of the motor speed, the sound pressure value of the bearing noise and the sound frequency in the audio file. Assume that Figure 2 After extracting the motor speed segments corresponding to the motor speeds of 2010 rpm, 2030 rpm, 2050 rpm, ..., 2490 rpm in (1), Fourier transform is performed to convert each motor speed segment into a corresponding motor speed curve segment, and the converted motor speed curve segments are arranged according to their corresponding motor speeds, so as to obtain the following: Figure 2 The second three-dimensional relationship diagram shown in (2) can reflect the corresponding relationship between the motor speed, the sound pressure value of the bearing noise and the sound frequency.

[0106] The peak value marked with 4.66 in the three-dimensional relationship diagram indicates that the bearing fault order is 4.66, and so on. Figure 2 The x-coordinate is the sound frequency, the y-coordinate is the motor speed, and the z-coordinate is the sound pressure value of the bearing noise.

[0107] by Figure 3 Take this as an example to illustrate: Figure 3 (1) is the second three-dimensional relationship diagram. By projecting the three-dimensional relationship diagram from top to bottom, it can be transformed into Figure 3 In the target relationship diagram shown in (2), the horizontal axis in the diagram is the sound frequency, the vertical axis is the motor speed, and the color scale card on the far right is used to mark the color of the target relationship diagram to indicate the size of the sound amplitude. Figure 3 The x-coordinate in (1) is the sound frequency, the y-coordinate is the motor speed, and the z-coordinate is the sound pressure value of the bearing noise.

[0108] Step A12, substituting the geometric parameters of the bearing into the bearing fault frequency calculation formula, calculating the bearing fault order of 1 times the frequency, and then multiplying the bearing fault order of 1 times the frequency by other consecutive times in sequence to obtain multiple bearing fault orders of different times.

[0109] The bearing fault frequency calculation formula predicts the bearing fault frequency based on the bearing's geometric parameters, and the bearing fault order is the ratio of the fault frequency to the sound frequency. The bearing fault frequency (i.e., abnormal sound frequency) corresponding to the bearing is calculated using the conventional bearing fault frequency calculation formula. The ratio between the abnormal sound frequency and its corresponding motor speed is calculated and used as the bearing fault order where the bearing may have a fault. The bearing fault order is 1 times the frequency. Since the vibration frequency generated by the bearing fault point during the bearing rotation process is not just 1 times the frequency, it is necessary to multiply the 1 times the frequency bearing fault order by other continuous integer multiples to obtain multiple bearing fault orders with different times the frequency.

[0110] For example, if the bearing fault order of 1 times the frequency is 4.66, then the bearing fault order of 2 times the frequency is 9.32, and the bearing fault order of 3 times the frequency is 13.98, and so on, the bearing fault order of possible bearing faults is predicted.

[0111] The calculated bearing fault orders of different frequencies will be reflected on the target relationship diagram. Figure 4 Take Figure 4 The two intersecting blue lines in (1) are regarded as a plane, which intersects with the target relationship diagram at a cross section. The curve of the cross section is as follows: Figure 4 As shown in (2) in the figure, the curve is the corresponding relationship between the sound amplitude and the motor speed corresponding to the order slice of the bearing fault order of 4.66. Figure 4 After the three-dimensional relationship diagram in (1) is projected from top to bottom, the bearing fault order corresponding to each frequency multiplication will also be reflected on the target relationship diagram. Figure 4 The x-coordinate in (1) is the sound frequency, the y-coordinate is the motor speed, and the z-coordinate is the sound pressure value of the bearing noise. Figure 4 The x-coordinate in (2) is the motor speed, and the y-coordinate is the sound pressure value of the bearing noise.

[0112] At the same time, the bearing fault order corresponds to the abnormal audio amplitude that can be detected in the audio amplitude, so the calculated bearing fault order can be used as a reference point for fault detection.

[0113] Step A13, according to the bearing fault orders corresponding to each preset integer multiple in the preset multiple interval, the target relationship diagram is sliced ​​to obtain a first target bearing fault order, and based on the bearing fault order corresponding to the preset decimal multiple, the target relationship diagram is sliced ​​to obtain a second target bearing fault order, wherein the target multiple includes a preset integer multiple and a preset decimal multiple, and the target bearing fault order includes a first target bearing fault order and a second target bearing fault order.

[0114] Taking the preset frequency multiple interval of [n, m] as an example, the first target bearing fault order obtained by order slicing the target relationship diagram is the bearing fault order corresponding to the nth frequency multiple to the bearing fault order corresponding to the mth frequency multiple.

[0115] The preset fractional multiple x in this embodiment is (n-1 / 2) multiple or (n+1 / 2) multiple, and the second target bearing fault order obtained by order slicing is the bearing fault order of x+0 multiple, the bearing fault order of x+1 multiple,..., the bearing fault order of x+(mn) multiple.

[0116] Assuming that the preset frequency multiplication interval is [4, 5], the bearing fault order is 4.66. Therefore, the first target bearing fault order obtained by order slicing the target relationship diagram is the first target bearing fault order 18.64 corresponding to 4 times the frequency and the first target bearing fault order 23.3 corresponding to 5 times the frequency, and the second target bearing fault order is the bearing fault order 16.31 corresponding to 3.5 times the frequency and the bearing fault order 20.97 corresponding to 4.5 times the frequency, or the bearing fault order 20.97 corresponding to 4.5 times the frequency and the bearing fault order 25.63 corresponding to 5.5 times the frequency.

[0117] Step A14, calculating a first root mean square value of the slice curve of each first target bearing fault order, and a second root mean square value of the slice curve of each second target bearing fault order.

[0118] It should be noted that the first root mean square value is the root mean square value corresponding to the first target bearing fault order, which can reflect the fluctuation of the abnormal sound pressure amplitude on the first target bearing fault order; the second root mean square value is the root mean square value corresponding to the second target bearing fault order slicing curve, which can reflect the fluctuation of the abnormal sound pressure amplitude on the second target bearing fault order corresponding to the integer multiple of the offset preset multiple frequency interval.

[0119] Step A15, after adding the first RMS values ​​to obtain a first sum value and adding the second RMS values ​​to obtain a second sum value, the second sum value is subtracted from the first sum value to obtain a target fault judgment threshold value.

[0120] The first root mean square values ​​corresponding to the first target bearing fault orders are added together, and the first sum value obtained can be used to evaluate the fault sound pressure amplitude of the bearing fault order with integer multiples, that is, the energy level; the second root mean square values ​​corresponding to the second target bearing orders are added together, and the second sum value obtained can be used to evaluate the fault sound pressure amplitude of the bearing fault order with offset integer multiples, that is, the energy level. Therefore, the target fault judgment threshold obtained by subtracting the second sum value from the first sum value can reflect the energy level difference between the first target bearing fault order and the second target bearing order.

[0121] Step A16, determine the first preset judgment threshold corresponding to the first fault judgment threshold calculation method, and obtain the comparison result between the target fault judgment threshold and the first preset judgment threshold, wherein the first preset judgment threshold is the lower limit difference of the bearing fault.

[0122] Because the target fault judgment threshold calculated through the above steps is a threshold that reflects the difference in energy levels between the first target bearing fault order and the second target bearing order, the first preset judgment threshold selected at this time should be the lower limit difference between the energy level of the first target bearing fault order and the second target bearing order for the bearing to be in a fault state. The first preset judgment threshold is compared with the target fault judgment threshold, and the comparison result obtained is the fault judgment result of the bearing.

[0123] Step A17: If the comparison result is that the target fault judgment threshold is equal to or greater than the first preset judgment threshold, it is determined that the bearing is in a fault state.

[0124] Step A18: If the comparison result is that the target fault judgment threshold is less than the first preset judgment threshold, it is determined that the bearing is not in a fault state.

[0125] Because under normal circumstances, the energy level corresponding to the first target bearing fault order and the energy level corresponding to the second target bearing fault order should be similar, that is, the target fault judgment threshold should be smaller than the first preset judgment threshold under normal circumstances. If the target fault judgment threshold is equal to or greater than the first preset judgment threshold, it means that there is a significant difference between the energy level corresponding to the first target bearing fault order and the energy level corresponding to the second target bearing fault order, indicating that the energy levels of some bearing fault orders are abnormally elevated, which is usually caused by bearing faults.

[0126] Therefore, when the comparison result obtained is that the target fault judgment threshold is greater than the first preset judgment threshold, it means that the bearing is in a fault state at this time; if the comparison result obtained is that the target fault judgment threshold is less than the first preset judgment threshold, it means that the bearing is not in a fault state at this time.

[0127] In a second feasible implementation manner, when the preset fault judgment threshold calculation method is the second fault judgment threshold calculation method, the bearing fault judgment method includes steps B11 to B19:

[0128] Step B11, based on the second fault judgment threshold calculation method, convert the audio file into a target relationship diagram between the sound amplitude and the sound frequency at each motor speed.

[0129] Step B12, substituting the geometric parameters of the bearing into the bearing fault frequency calculation formula, calculating the bearing fault order of 1 times the frequency, and then multiplying the bearing fault order of 1 times the frequency by other continuous times in sequence to obtain multiple bearing fault orders of different times.

[0130] Step B13, according to the bearing fault orders corresponding to each preset integer multiple frequency in the preset multiple frequency interval, the target relationship diagram is sliced ​​by order to obtain a first target bearing fault order, and based on the bearing fault order corresponding to the preset decimal multiple frequency, the target relationship diagram is sliced ​​by order to obtain a second target bearing fault order, wherein the target multiple frequency includes a preset integer multiple frequency and a preset decimal multiple frequency, and the target bearing fault order includes a first target bearing fault order and a second target bearing fault order.

[0131] Step B14, calculating a first root mean square value of each first target bearing fault order, and a second root mean square value of each second target bearing fault order.

[0132] The process steps of step B11 to step B14 in this embodiment are the same as the process steps of step A11 to step A14 in the previous embodiment, and will not be repeated here.

[0133] Step B15, according to the correspondence between each preset integer multiple frequency and each decimal multiple frequency, obtaining the difference between each first root mean square value and the second root mean square value corresponding to each first root mean square value.

[0134] The corresponding relationship in this embodiment is that the order size of the first target bearing order corresponding to each preset integer multiple frequency corresponds to the order size of the second target bearing order corresponding to each decimal multiple frequency.

[0135] Taking the preset frequency multiple interval [n, m] as an example, the first target bearing fault order obtained by order slicing the target relationship diagram is the bearing fault order corresponding to the n-frequency multiple to the bearing fault order corresponding to the m-frequency multiple. The preset fractional frequency multiple x is (n-1 / 2) frequency multiple or (n+1 / 2) frequency multiple, and the second target bearing fault order obtained by order slicing is the bearing fault order of x+0 frequency multiple, the bearing fault order of x+1 frequency multiple, ..., the bearing fault order of x+(mn) frequency multiple.

[0136] The difference calculation in this embodiment is: calculating the difference between the first root mean square value of the first target bearing order slicing curve of n times the frequency and the second root mean square value of the bearing fault order slicing curve of x+0 times the frequency, calculating the difference between the first root mean square value of the first target bearing order slicing curve of (n+1) times the frequency and the second root mean square value of the bearing fault order slicing curve of x+1 times the frequency, calculating the difference between the first root mean square value of the first target bearing order slicing curve of (n+2) times the frequency and the second root mean square value of the bearing fault order slicing curve of x+2 times the frequency, ..., calculating the difference between the first root mean square value of the first target bearing order slicing curve of m times the frequency and the second root mean square value of the bearing fault order slicing curve of x+(mn) times the frequency, and rotating the bearing in this way to calculate the energy level difference between the corresponding first target bearing fault order and the second target bearing order.

[0137] Step B16, counting the number of differences greater than a first preset judgment threshold, and determining the number of differences as a target fault judgment threshold, wherein the first preset judgment threshold is a lower limit difference for bearing faults.

[0138] The energy level between the first target bearing fault order and the second target bearing order when the bearing rotates is selected as the lower limit difference value that the bearing is in a fault state. After the lower limit difference value is determined as the first preset judgment threshold, the differences calculated through the above steps are compared with the first preset judgment threshold value respectively, and the number of differences greater than the first preset judgment threshold value is counted, that is, the number of differences with large energy level differences between the first target bearing fault order and the second target bearing fault order corresponding to the bearing rotation is counted, and the difference number is determined as the target fault judgment threshold.

[0139] Step B17, determine the second preset judgment threshold corresponding to the second fault judgment threshold calculation method, and obtain the comparison result between the target fault judgment threshold and the second preset judgment threshold, wherein the second preset judgment threshold is the lower limit number threshold of bearing faults.

[0140] Because the target fault judgment threshold calculated through the above steps reflects the energy level difference between the first target bearing fault order and the second target bearing order, the second preset judgment threshold selected at this time should be the lower limit number threshold of the bearing in a fault state. The second preset judgment threshold is compared with the target fault judgment threshold, and the comparison result is the fault judgment result of the bearing.

[0141] Step B18: If the comparison result is that the target fault judgment threshold is equal to or greater than the second preset judgment threshold, it is determined that the bearing is in a fault state.

[0142] Step B19: If the comparison result is that the target fault judgment threshold is less than the second preset judgment threshold, it is determined that the bearing is not in a fault state.

[0143] When the control result obtained through comparison is that the target fault judgment threshold is equal to or greater than the second preset judgment threshold, it means that there is an energy level that exceeds the energy level under normal circumstances, indicating that there is a significant difference between the energy level corresponding to the first target bearing fault order and the energy level corresponding to the second target bearing fault order, that is, during the rotation of the bearing, the frequency of bearing faults is higher, and the bearing is considered to be in a faulty state at this time; if the control result obtained through comparison is that the target fault judgment threshold is less than the second preset judgment threshold, it means that there is an energy level that does not exceed the energy level under normal circumstances, that is, during the rotation of the bearing, the frequency of bearing faults is lower, and the bearing is considered not to be in a faulty state at this time.

[0144] In a third feasible implementation manner, when the preset fault judgment threshold calculation method is the third fault judgment threshold calculation method, the bearing fault judgment method includes steps C11 to C19:

[0145] Step C11, based on the third fault judgment threshold calculation method, perform Hilbert transform on the sound signal in the audio file, extract the envelope of the sound signal after the Hilbert transform, and obtain the envelope signal of the sound signal.

[0146] By using the third fault judgment threshold calculation method, the sound signal in the audio file is subjected to Hilbert transformation, thereby analyzing the sound signal and obtaining an envelope signal that can reflect the instantaneous amplitude of the sound signal.

[0147] Step C12, converting the envelope signal and the speed signal in the audio file into a target relationship diagram between the sound amplitude and the sound frequency at each motor speed.

[0148] The conversion process is consistent with the conversion process in step A12, the only difference is that because the present embodiment performs Hilbert transform and envelope processing on the sound signal in the audio file, the target relationship diagram obtained by the final conversion is as follows: Figure 5 As shown, compared with the target relationship diagram obtained after Fourier transform based on the sound signal and the speed signal, the target relationship diagram in this embodiment can more detailedly reflect the correspondence between the sound amplitude and the sound frequency at the motor speed corresponding to multiple moments.

[0149] Step C13, substituting the geometric parameters of the bearing into the bearing fault frequency calculation formula, calculating the bearing fault order of 1 times the frequency, and obtaining the third target bearing fault order.

[0150] The process steps are the same as step A13 and will not be repeated here.

[0151] Step C14, slicing the target relationship diagram based on the preset frequency multiplication to obtain a fourth target bearing fault order.

[0152] That is, in this embodiment, the target relationship diagram is directly sliced ​​based on the bearing fault order of 1 frequency obtained in step C13 to obtain the third target bearing fault order, and the target relationship diagram is sliced ​​based on a single preset frequency to obtain the fourth target bearing fault order. The preset frequency should avoid being an integer frequency, and can be a fractional frequency that deviates from 1 frequency.

[0153] Assuming that the bearing fault order of 1 frequency can be obtained based on step C13, the target relationship diagram is directly sliced ​​based on the bearing fault order of 1 frequency to obtain the third target bearing fault order corresponding to the bearing fault order of 1 frequency. At the same time, assuming that the preset frequency is 3 / 2 times the frequency, the target relationship diagram is sliced ​​based on the bearing fault order of 3 / 2 times the frequency to obtain the fourth target bearing fault order corresponding to the bearing fault order of 3 / 2 times the frequency.

[0154] Step C15, calculating a third root mean square value corresponding to the sound pressure value of the third target bearing fault order slice curve, and a fourth root mean square value corresponding to the sound pressure value of the fourth target bearing fault order slice curve.

[0155] It should be noted that the third root mean square value is the root mean square value corresponding to the sound pressure value of the corresponding third target bearing fault order slicing curve, which can reflect the fluctuation of the abnormal sound pressure amplitude on the third target bearing fault order. The fourth root mean square value is the root mean square value corresponding to the sound pressure value of the corresponding fourth target bearing fault order slicing curve, which can reflect the sound frequency fluctuation on the fourth target bearing fault order corresponding to the integer multiple of the offset preset multiple interval.

[0156] Step C16: Determine the difference obtained by subtracting the fourth root mean square value from the third root mean square value as the target fault judgment threshold.

[0157] Under normal circumstances, the third root mean square value of the third bearing fault order will be relatively high, because the fault will cause periodic impact signals. These impact signals appear in the sound signal in the form of high-frequency components. After Hilbert transform and envelope processing, they can be more clearly identified. The harmonic components of the fourth fault characteristic order (such as 3 / 2 times the frequency) also exist in the sound signal, but are usually not as obvious as the fundamental frequency components. Therefore, the fourth root mean square value of 3 / 2 times the third bearing fault characteristic order is usually low.

[0158] When a bearing fault occurs, the third RMS value will increase significantly. If the third RMS value is much larger than the fourth RMS value, this indicates that the energy concentration of the fault sound pressure amplitude of the bearing exists, while its harmonic components are relatively weak. Therefore, the target fault judgment threshold determined by the difference between the third RMS value and the fourth RMS value can be used to characterize the energy concentration of the fault sound pressure amplitude of the bearing.

[0159] Step C17, determine the third preset judgment threshold corresponding to the third fault judgment threshold calculation method, and obtain the comparison result between the target fault judgment threshold and the third preset judgment threshold, wherein the third preset judgment threshold is the lower limit value of the bearing fault.

[0160] Because the target fault judgment threshold calculated through the above steps reflects the energy concentration of the fault sound pressure amplitude of the bearing, the third preset judgment threshold selected at this time should be the lower limit of the energy concentration of the fault sound pressure amplitude when the bearing is in a fault state. The third preset judgment threshold is compared with the target fault judgment threshold, and the comparison result is the fault judgment result of the bearing.

[0161] Step C18: If the comparison result is that the target fault judgment threshold is equal to or greater than the third preset judgment threshold, it is determined that the bearing is in a fault state.

[0162] Step C19: If the comparison result is that the target fault judgment threshold is less than the third preset judgment threshold, it is determined that the bearing is not in a fault state.

[0163] When the control result obtained through comparison is that the target fault judgment threshold is equal to or greater than the third preset judgment threshold, it means that the energy of the fault sound pressure amplitude of the bearing is relatively concentrated, that is, the difference in the energy distribution of the bearing exceeds the normal range, and the bearing is considered to be in a faulty state; if the control result obtained through comparison is that the target fault judgment threshold is less than the third preset judgment threshold, it means that the energy of the fault sound pressure amplitude of the bearing is relatively dispersed, that is, the difference in the energy distribution of the bearing does not exceed the normal range, and the bearing is considered not to be in a faulty state.

[0164] It should be noted that, based on the actual bearing fault judgment needs, one or more of the above-mentioned first fault judgment threshold calculation method, second fault judgment threshold calculation method and third fault judgment threshold calculation method can be arbitrarily selected and used in combination, and the bearing fault judgment result obtained by judgment is passed to the electronic control processor, and the bearing fault judgment result is uploaded to the vehicle control unit through the electronic control processor, so that the vehicle control unit can perform processing and judgment based on the bearing fault judgment result, and judge whether to execute the operation of reminding the user to repair the bearing or replace the electric drive in time.

[0165] For example, in order to help understand the implementation process of the bearing fault judgment method obtained by combining this embodiment with the above-mentioned embodiment 1, please refer to Figure 6 , Figure 6 A brief flow chart of a bearing fault judgment method is provided, specifically:

[0166] The data acquisition unit collects in real time the initial speed signal and the initial sound signal during the transition period when the rotation speed of the bearing changes when the vehicle is in a driving state, intercepts the initial speed signal and the initial sound signal based on a preset period, and generates an audio file in a preset format (i.e. Figure 6 Step S2 in the above example) determines whether to enter the bearing fault determination state (i.e. Figure 6If the step S3 is entered, the audio file is converted into a target relationship diagram by a preset fault judgment threshold calculation method, and the bearing fault order is calculated on the target relationship diagram. The target relationship diagram is sliced ​​according to the bearing fault order, and the target bearing fault order corresponding to the target frequency multiplication is obtained. Then, the target fault judgment threshold (i.e. Figure 6 In step S4), a preset judgment threshold corresponding to the preset fault judgment threshold calculation method is selected, and compared with the target fault judgment threshold, and based on the comparison result, it is determined whether the bearing is in a fault state (i.e. Figure 6 In step S5), the bearing fault judgment result is transmitted to the electronic control processor, and the bearing fault judgment result is uploaded to the vehicle control unit (i.e. Figure 6 Step S6 in the process) enables the vehicle control unit to process and judge based on the bearing fault judgment result to determine whether to perform the operation of reminding the user to repair the bearing or replace the electric drive in time (i.e. Figure 6 Step S7 in ).

[0167] It should be noted that the above examples are only used to understand the present application and do not constitute a limitation on the bearing fault judgment method of the present application. More simple transformations based on this technical concept are all within the protection scope of the present application.

[0168] The present application provides an electric drive assembly, which includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the bearing fault judgment method in the above-mentioned embodiment one.

[0169] Reference below Figure 7 , which shows a schematic diagram of the structure of an electric drive assembly suitable for implementing the embodiment of the present application. The electric drive assembly in the embodiment of the present application may include but is not limited to mobile terminals such as PDA (Personal Digital Assistant), PMP (Portable Media Player), vehicle-mounted terminals (such as vehicle-mounted navigation terminals), etc., and fixed terminals such as digital TV, desktop computers, etc. Figure 7 The electric drive assembly shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0170] like Figure 7As shown, the electric drive assembly may include a processing device 1001 (e.g., a central processing unit, a graphics processor, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM: Read Only Memory) 1002 or a program loaded from a storage device 1003 to a random access memory (RAM: Random Access Memory) 1004. In RAM1004, various programs and data required for the operation of the electric drive assembly are also stored. The processing device 1001, ROM1002, and RAM1004 are connected to each other through a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Generally, the following systems can be connected to the I / O interface 1006: an input device 1007 including, for example, a touch screen, a touch pad, a keyboard, a mouse, an image sensor, a microphone, an accelerometer, a gyroscope, etc.; an output device 1008 including, for example, a liquid crystal display (LCD: Liquid Crystal Display), a speaker, a vibrator, etc.; a storage device 1003 including, for example, a magnetic tape, a hard disk, etc.; and a communication device 1009. The communication device 1009 can allow the electric drive assembly to communicate with other devices wirelessly or by wire to exchange data. Although the figure shows an electric drive assembly with various systems, it should be understood that it is not required to implement or have all the systems shown. More or fewer systems can be implemented or have alternatively.

[0171] In particular, according to the embodiments disclosed in the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments disclosed in the present application include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through a communication device, or installed from a storage device 1003, or installed from a ROM 1002. When the computer program is executed by the processing device 1001, the above-mentioned functions defined in the method of the embodiment disclosed in the present application are executed.

[0172] The electric drive assembly provided by the present application adopts the bearing fault judgment method in the above embodiment, which can solve the technical problem of low bearing fault detection accuracy in conventional bearing fault judgment schemes. Compared with the prior art, the beneficial effects of the electric drive assembly provided by the present application are the same as the beneficial effects of the bearing fault judgment method provided by the above embodiment, and the other technical features in the electric drive assembly are the same as the features disclosed in the method of the previous embodiment, which will not be repeated here.

[0173] It should be understood that the various parts disclosed in this application can be implemented by hardware, software, firmware or a combination thereof. In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0174] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0175] The present application provides a computer-readable storage medium having computer-readable program instructions (ie, computer programs) stored thereon, and the computer-readable program instructions are used to execute the bearing fault determination method in the above-mentioned embodiment.

[0176] The computer-readable storage medium provided in the present application may be, for example, a USB flash drive, but is not limited to electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems or devices, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM: Random Access Memory), a read-only memory (ROM: Read Only Memory), an erasable programmable read-only memory (EPROM: Erasable Programmable Read Only Memory or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM: CD-Read Only Memory), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system or device. The program code contained on the computer-readable storage medium may be transmitted using any appropriate medium, including but not limited to: wires, optical cables, RF (Radio Frequency: Radio Frequency), etc., or any suitable combination of the above.

[0177] The computer-readable storage medium may be included in the electric drive assembly; or may exist independently without being assembled into the electric drive assembly.

[0178] The computer-readable storage medium carries one or more programs. When the one or more programs are executed by the electric drive assembly, the electric drive assembly: converts the speed signal and sound signal collected in real time by the data acquisition unit into a target relationship diagram between the sound amplitude and the sound frequency at each motor speed through a preset fault judgment threshold calculation method, wherein the speed signal is the motor speed of the bearing in a preset time period, and the sound signal is the sound amplitude and sound frequency generated when the bearing vibrates in the preset time period; calculates a plurality of bearing fault orders of different multiples on the target relationship diagram, and performs order slicing on the target relationship diagram according to the bearing fault order, obtains the target bearing fault orders corresponding to the plurality of target multiples, and obtains the target fault judgment threshold based on each target bearing fault order; selects the preset judgment threshold corresponding to the preset fault judgment threshold calculation method, compares it with the target fault judgment threshold, and determines whether the bearing is in a fault state according to the comparison result.

[0179] Computer program code for performing the operations of the present application may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0180] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0181] The modules involved in the embodiments described in this application may be implemented by software or hardware, wherein the name of the module does not constitute a limitation on the unit itself in some cases.

[0182] The readable storage medium provided by the present application is a computer-readable storage medium, which stores computer-readable program instructions (i.e., computer programs) for executing the above-mentioned bearing fault judgment method, and can solve the technical problem that the conventional bearing fault judgment scheme has low bearing fault detection accuracy. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided by the present application are the same as the beneficial effects of the bearing fault judgment method provided by the above-mentioned embodiment, and will not be repeated here.

[0183] The above descriptions are only some embodiments of the present application, and are not intended to limit the patent scope of the present application. All equivalent structural changes made using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect applications in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A bearing fault judgment method, characterized in that: The bearing fault judgment method is applied to an electric drive assembly, the electric drive assembly includes an electric drive control system, a data acquisition unit is installed on a circuit board where the electric drive control system is located, and the bearing fault judgment method includes: By means of a preset fault judgment threshold calculation method, the speed signal and the sound signal collected in real time by the data acquisition unit are converted into a target relationship diagram between the sound amplitude and the sound frequency at each motor speed, wherein the speed signal is the motor speed of the bearing in a preset period of time, and the sound signal is the sound amplitude and the sound frequency generated when the bearing vibrates in the preset period of time; The bearing fault order is calculated on the target relationship diagram, and the target relationship diagram is sliced ​​according to the bearing fault order to obtain the target bearing fault order corresponding to the target frequency multiplication, and then the target fault judgment threshold is obtained based on each of the target bearing fault orders; A preset judgment threshold corresponding to the preset fault judgment threshold calculation method is selected, and compared with the target fault judgment threshold, and whether the bearing is in a fault state is determined based on the comparison result.

2. The bearing fault judgment method according to claim 1, characterized in that: Before the step of converting the speed signal and the sound signal collected in real time by the data acquisition unit into a target relationship diagram between the sound amplitude and the sound frequency at each motor speed by using a preset fault judgment threshold calculation method, the step also includes: The data acquisition unit is used to collect in real time an initial speed signal and an initial sound signal during a transition period when the rotation speed of the bearing changes while the vehicle is in a driving state; Based on the preset time period, the initial rotation speed signal and the initial sound signal are intercepted to generate an audio file in a preset format, wherein the audio file includes the rotation speed signal and the sound signal in the preset time period; and, According to the motor speed and the motor speed difference of the initial speed signal at any time point in the transition period, when it is obtained that the motor speed is greater than the preset motor speed or the motor speed difference is greater than the preset motor speed difference, the bearing fault judgment state is entered, and the preset fault judgment threshold calculation method is executed to convert the speed signal and the sound signal collected in real time by the data acquisition unit into a target relationship diagram between the sound amplitude and the sound frequency at each motor speed.

3. The bearing fault judgment method according to claim 2, characterized in that: In the case where the preset fault judgment threshold value calculation method called is the first fault judgment threshold value calculation method or the second fault judgment threshold value calculation method, the step of converting the speed signal and the sound signal collected in real time by the data acquisition unit into a target relationship diagram between the sound amplitude and the sound frequency at each motor speed by using the preset fault judgment threshold value calculation method comprises: Based on the first fault judgment threshold calculation method or the second fault judgment threshold calculation method, the audio file is converted into a target relationship diagram between the sound amplitude and the sound frequency at each motor speed.

4. The bearing fault determination method according to claim 3, characterized in that: The step of calculating the bearing fault order on the target relationship diagram, slicing the target relationship diagram according to the bearing fault order, and obtaining the target bearing fault order corresponding to the target frequency multiplication, and then obtaining the target fault judgment threshold based on each target bearing fault order includes: Substituting the geometric parameters of the bearing into the bearing fault frequency calculation formula to calculate the bearing fault order of 1 times the frequency, multiplying the bearing fault order of 1 times the frequency by other continuous times in sequence to obtain multiple bearing fault orders of different times the frequency; According to the bearing fault orders corresponding to each preset integer multiple frequency in the preset multiple frequency interval, the target relationship diagram is sliced ​​by order to obtain a first target bearing fault order, and based on the bearing fault order corresponding to the preset decimal multiple frequency, the target relationship diagram is sliced ​​by order to obtain a second target bearing fault order, wherein the target multiple frequency includes the preset integer multiple frequency and the preset decimal multiple frequency, and the target bearing fault order includes the first target bearing fault order and the second target bearing fault order; Calculate the first root mean square value of the slice curve of each of the first target bearing fault orders, and the second root mean square value of the slice curve of each of the second target bearing fault orders, and obtain the target fault judgment threshold based on each of the first root mean square values ​​and each of the second root mean square values.

5. The bearing fault determination method according to claim 4, characterized in that: In a case where the called preset fault judgment threshold calculation method is the first fault judgment threshold calculation method, the step of obtaining the target fault judgment threshold based on each of the first root mean square values ​​and each of the second root mean square values ​​includes: After adding the first root mean square values ​​to obtain a first sum value and adding the second root mean square values ​​to obtain a second sum value, subtracting the second sum value from the first sum value to obtain the target fault judgment threshold value; The step of selecting a preset judgment threshold corresponding to the preset fault judgment threshold calculation method, comparing it with the target fault judgment threshold, and determining whether the bearing is in a fault state according to the comparison result includes: Determine a first preset judgment threshold corresponding to the first fault judgment threshold calculation method, and obtain a comparison result between the target fault judgment threshold and the first preset judgment threshold, wherein the first preset judgment threshold is a lower limit difference of the bearing fault; If the comparison result is that the target fault judgment threshold is equal to or greater than the first preset judgment threshold, it is determined that the bearing is in a fault state; If the comparison result is that the target fault judgment threshold is less than the first preset judgment threshold, it is determined that the bearing is not in a fault state.

6. The bearing fault determination method according to claim 4, characterized in that: In a case where the called preset fault judgment threshold calculation method is the second fault judgment threshold calculation method, the step of obtaining the target fault judgment threshold based on each of the first root mean square values ​​and each of the second root mean square values ​​includes: According to the correspondence between each of the preset integer multiples and each of the fractional multiples, obtaining a difference between each of the first root mean square values ​​and a second root mean square value corresponding to each of the first root mean square values; Counting the number of differences greater than a first preset judgment threshold, and determining the number of differences as the target fault judgment threshold, wherein the first preset judgment threshold is the lower limit difference of the bearing fault; The step of selecting a preset judgment threshold corresponding to the preset fault judgment threshold calculation method, comparing it with the target fault judgment threshold, and determining whether the bearing is in a fault state according to the comparison result includes: Determine a second preset judgment threshold corresponding to the second fault judgment threshold calculation method, and obtain a comparison result between the target fault judgment threshold and the second preset judgment threshold, wherein the second preset judgment threshold is a lower limit number threshold of the bearing fault; If the comparison result is that the target fault judgment threshold is equal to or greater than the second preset judgment threshold, it is determined that the bearing is in a fault state; If the comparison result is that the target fault judgment threshold is less than the second preset judgment threshold, it is determined that the bearing is not in a fault state.

7. The bearing fault determination method according to claim 2, characterized in that: In the case where the preset fault judgment threshold calculation method called is the third fault judgment threshold calculation method, the step of converting the speed signal and the sound signal collected in real time by the data acquisition unit into a target relationship diagram between the sound amplitude and the sound frequency at each motor speed by using the preset fault judgment threshold calculation method includes: Based on the third fault judgment threshold calculation method, the sound signal in the audio file is subjected to a Hilbert transform, and the envelope of the sound signal after the Hilbert transform is extracted to obtain an envelope signal of the sound signal; The envelope signal and the speed signal in the audio file are converted into the target relationship diagram between the sound amplitude and the sound frequency at each motor speed.

8. The bearing fault determination method according to claim 7, characterized in that: The bearing fault order is calculated on the target relationship diagram, and the target relationship diagram is sliced ​​according to the bearing fault order to obtain the target bearing fault order corresponding to the target frequency multiplication. The step of obtaining the target fault judgment threshold based on each target bearing fault order includes: Substituting the geometric parameters of the bearing into the bearing fault frequency calculation formula, calculating the bearing fault order of 1 times the frequency, and obtaining the third target bearing fault order; Slicing the target relationship diagram in order based on a preset frequency multiplication to obtain a fourth target bearing fault order; Calculating a third root mean square value corresponding to the slice curve sound pressure value of the third target bearing fault order, and a fourth root mean square value corresponding to the slice curve sound pressure value of the fourth target bearing fault order; Determine a difference value obtained by subtracting the fourth root mean square value from the third root mean square value as the target fault judgment threshold; The step of selecting a preset judgment threshold corresponding to the preset fault judgment threshold calculation method, comparing it with the target fault judgment threshold, and determining whether the bearing is in a fault state according to the comparison result includes: Determine a third preset judgment threshold corresponding to the third fault judgment threshold calculation method, and obtain a comparison result between the target fault judgment threshold and the third preset judgment threshold, wherein the third preset judgment threshold is a lower limit difference of the bearing fault; If the comparison result is that the target fault judgment threshold is equal to or greater than the third preset judgment threshold, it is determined that the bearing is in a fault state; If the comparison result is that the target fault judgment threshold is less than the third preset judgment threshold, it is determined that the bearing is not in a fault state.

9. An electric drive assembly, characterized in that: The electric drive assembly includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the bearing fault judgment method according to any one of claims 1 to 8.

10. A storage medium, characterized in that: The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, the steps of the bearing fault judgment method according to any one of claims 1 to 8 are implemented.

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