Local fault diagnosis method and system for double-row planetary gear

Abstract

The invention belongs to the technical field of fault diagnosis. The invention provides the local fault diagnosis method and system for the double-row planetary gear, multiple broken tooth aesthetic models are constructed, and fault simulation is performed through the models, so that the states of different parts during tooth breakage can be comprehensively and meticulously analyzed, the fault recognition is more targeted and accurate, and the fault diagnosis accuracy is improved. Rapid identification of broken teeth of a sun gear and broken teeth of a planetary gear is realized, faults can be timely perceived, more serious equipment damage caused by fault delay is avoided, maintenance cost and downtime are effectively reduced, the operation efficiency of equipment is improved, and through analysis of modulation harmonic wave and impact characteristics in a time domain image and a frequency domain image, the fault detection accuracy is improved. According to the method, whether the fault exists or not and the specific position of the fault can be accurately judged, the conditions of misdiagnosis and missed diagnosis are reduced, a reliable basis is provided for subsequent maintenance work, and the technical blank of double-row planetary gear fault recognition is filled up.

Description

Technical Field

[0001] The present invention relates to the technical field of fault diagnosis, and in particular to a local fault diagnosis method and system for a double-row planetary gear. Background Art

[0002] The statements in this section merely provide background art related to the present invention and do not necessarily constitute prior art.

[0003] Due to their high power density and compact structure, planetary gear trains are widely used in key applications such as automotive transmissions, wind power equipment, and aerospace. In recent years, the dual-row serially connected planetary gear (DRSCPG), with its unique single sun gear, dual planetary gears in series, and ring gear power transmission path, has demonstrated technical advantages such as higher transmission ratios and layout flexibility, making it a preferred solution for multi-speed transmission and high-efficiency mechanical systems. This mechanism consists of a single sun gear, a first row of planetary gears (meshing with the sun gear), a second row of planetary gears (meshing with the ring gear), and a ring gear. Each planetary gear in the first row meshes with its corresponding planetary gear in the second row.

[0004] Tooth breakage faults in double-row planetary gear trains may cause system failure and result in serious consequences. The unique transmission path of the double-row planetary gear train, which consists of a single sun gear, a double-row planetary gear in series, and a ring gear, makes its dynamic behavior far more complex than that of a single-row planetary gear train. Existing research methods and theoretical frameworks are mostly based on single-row planetary gear trains and are difficult to apply directly to double-row structures. Due to the symmetry and coupling of the double-row structure, the manifestation of the fault characteristics is very different from that of the single-row structure. Traditional signal processing and analysis techniques make it difficult to accurately extract the characteristic information of the broken tooth fault in the double-row planetary gear train, resulting in the inability to effectively identify the fault. Summary of the Invention

[0005] In order to address the shortcomings of the existing technology, the present invention provides a local fault diagnosis method and system for double-row planetary gears, constructs a sun gear tooth breakage phenomenological model (a model that describes the phenomenon based on observation and experimental data), a first-row planetary gear tooth breakage phenomenological model (a planetary gear meshing with the sun gear), and a second-row planetary gear tooth breakage phenomenological model (a planetary gear meshing with the ring gear). This achieves rapid identification of sun gear tooth breakage, first-row planetary gear tooth breakage, and second-row planetary gear tooth breakage, greatly improving the accuracy of fault diagnosis.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a method for diagnosing local faults of a double-row planetary gear.

[0007] A local fault diagnosis method for a double-row planetary gear includes the following steps: A fault simulation is performed based on the operating parameters of the double-row planetary gears and the sun gear tooth-breaking phenomenological model to obtain a first time domain image and a first frequency domain image. When a first modulated harmonic appears within a set frequency range before and after the meshing frequency in the first frequency domain image, and an impact with a first set period interval exists in the first time domain image, a sun gear tooth-breaking fault is determined to be present. A fault simulation is performed based on the operating parameters of the double-row planetary gears and a phenomenological model of a broken tooth of a planetary gear meshing with the sun gear, to obtain a second time domain image and a second frequency domain image. When a second modulated harmonic appears within a set frequency range before and after the meshing frequency in the second frequency domain image, and an impact with a second set period interval is present in the second time domain image, a fault is determined in the planetary gear meshing with the sun gear. A fault simulation is performed based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken tooth of the planetary gear meshing with the ring gear. A third time domain image and a third frequency domain image are obtained. When a third modulated harmonic appears within a set frequency range before and after the meshing frequency in the third frequency domain image, and an impact with a third set period interval exists in the third time domain image, a fault is determined to be present in the planetary gear meshing with the ring gear.

[0008] In a second aspect, the present invention provides a local fault diagnosis system for double-row planetary gears.

[0009] A local fault diagnosis system for a double-row planetary gear, comprising: The sun gear tooth breakage identification unit is configured to: perform fault simulation based on the operating parameters of the double-row planetary gears and the sun gear tooth breakage phenomenological model to obtain a first time domain image and a first frequency domain image; and determine that a sun gear tooth breakage fault exists when a first modulated harmonic appears within a set frequency range before and after the meshing frequency in the first frequency domain image, and an impact with a first set period interval exists in the first time domain image; The first planetary gear broken tooth identification unit is configured to: perform a fault simulation based on the operating parameters of the double-row planetary gears and a phenomenological model of a broken tooth of a planetary gear meshing with the sun gear, obtain a second time domain image and a second frequency domain image, and determine that a planetary gear meshing with the sun gear is faulty when a second modulated harmonic appears within a set frequency range before and after the meshing frequency in the second frequency domain image, and an impact with a second set period interval exists in the second time domain image; The second planetary gear broken tooth identification unit is configured to: perform fault simulation based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken teeth of the planetary gear meshing with the ring gear, obtain a third time domain image and a third frequency domain image, and when a third modulated harmonic appears within a set frequency range before and after the meshing frequency in the third frequency domain image, and an impact of a third set period interval exists in the third time domain image, it is determined that the planetary gear meshing with the ring gear is faulty.

[0010] In a third aspect, the present invention provides a computer device comprising: a processor and a computer-readable storage medium; a processor adapted to execute a computer program; A computer-readable storage medium having a computer program stored therein, wherein when the computer program is executed by the processor, the local fault diagnosis method for the double-row planetary gear as described in the first aspect of the present invention is implemented.

[0011] In a fourth aspect, the present invention provides a computer-readable storage medium storing a computer program, wherein the computer program is suitable for being loaded by a processor and executing the local fault diagnosis method for double-row planetary gears as described in the first aspect of the present invention.

[0012] Compared with the prior art, the present invention has the following beneficial effects: The present invention innovatively proposes a local fault diagnosis method for double-row planetary gears, constructs a variety of broken tooth phenomenological models, covering the sun gear, the planetary gear meshing with the sun gear, and the planetary gear meshing with the ring gear, providing an accurate theoretical basis for fault diagnosis. By performing fault simulation through these models, the status of different components when the teeth are broken can be comprehensively and meticulously analyzed, making fault identification more targeted and accurate, and realizing rapid identification of sun gear tooth breakage and planetary gear tooth breakage. Faults can be detected in time to avoid more serious equipment damage caused by fault delays, effectively reducing maintenance costs and downtime, and improving equipment operating efficiency. By analyzing the characteristics of modulated harmonics and impulses in time domain images and frequency domain images, it can be accurately determined whether a fault exists and the specific location of the fault, reducing misdiagnosis and missed diagnosis, providing a reliable basis for subsequent maintenance work, filling the technical gap in double-row planetary gear fault identification, and helping to improve the reliability and stability of the double-row planetary gear system operation, and ensuring the safe operation of equipment in key fields such as automotive transmissions, wind power, and aerospace.

[0013] When identifying broken sun gear teeth, the present invention clarifies the relationship between the fault harmonics and the meshing frequency, the planetary carrier rotation frequency, and the number of planetary gears meshing with the sun gear, providing a clear theoretical basis for fault judgment. When the first modulated harmonic that conforms to the law of the expression appears in the set frequency range before and after the meshing frequency of the first frequency domain image, and there is an impact corresponding to the set period interval in the first time domain image, the broken sun gear tooth fault can be accurately determined. The same applies to the determination of broken tooth faults of the other two rows of planetary gears. This makes fault diagnosis no longer rely on vague empirical judgments, but is based on precise mathematical relationships, greatly improving the accuracy and reliability of fault diagnosis, effectively avoiding misdiagnosis and missed diagnosis, and providing a strong guarantee for the stable operation of the double-row planetary gear system.

[0014] When identifying broken teeth on a planetary gear meshing with the sun gear, the relationship between the fault harmonics and the meshing frequency, as well as the relative rotational frequency of the planetary gear meshing with the sun gear relative to the planet carrier, is defined. This provides a solid theoretical foundation for determining faults such as broken teeth on a planetary gear meshing with the sun gear. When a second modulated harmonic that conforms to this expression appears within a set frequency range before and after the meshing frequency in the second frequency domain image, and when the second time domain image has a corresponding set periodic interval impact, the broken tooth fault on the planetary gear meshing with the sun gear can be accurately determined. The same applies to faults on other rows of planetary gears. This provides precise quantitative standards for fault diagnosis, greatly improving the accuracy and scientific nature of diagnosis, effectively avoiding misdiagnosis and missed diagnosis due to subjective judgment, ensuring the stable operation of the double-row planetary gear system, and reducing the risk of equipment failure and maintenance costs.

[0015] When identifying broken teeth on a planetary gear meshing with the ring gear, an association is established between the fault harmonic and the meshing frequency, as well as the relative rotational frequency of the planetary gear meshing with the sun gear relative to the planetary carrier, providing rigorous theoretical support for fault determination. When a third modulated harmonic that meets the expression appears in the set frequency range before and after the meshing frequency in the third frequency domain image, and when there is an impact at the corresponding set periodic interval in the third time domain image, the broken tooth fault of the planetary gear meshing with the ring gear can be accurately determined. This logic can also be used for other fault determinations, greatly improving the accuracy and reliability of fault diagnosis, making the diagnostic process more systematic, and effectively avoiding errors caused by subjective assumptions. This helps to detect faults in a timely manner, ensure the stable and efficient operation of the double-row planetary gear system, and reduce the risks and losses caused by equipment failures.

[0016] Advantages of additional aspects of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0018] Figure 1 A schematic flow chart of a method for diagnosing a local fault of a double-row planetary gear provided by an exemplary embodiment of the present invention; Figure 2 A time domain image of a health status signal provided by an exemplary embodiment of the present invention; Figure 3 A frequency domain image of a health condition signal provided by an exemplary embodiment of the present invention; Figure 4 A time-domain simulation signal image of a sun gear tooth breakage provided by an exemplary embodiment of the present invention; Figure 5An image of a frequency domain simulation signal of a sun gear broken tooth provided by an exemplary embodiment of the present invention; Figure 6 An image of a time-domain simulation signal of a broken tooth of a planetary gear meshing with a sun gear provided as an exemplary embodiment of the present invention; Figure 7 An image of a frequency domain analog signal of a broken tooth of a planetary gear meshing with a sun gear provided in accordance with an exemplary embodiment of the present invention; Figure 8 An image of a time-domain simulation signal of a broken tooth of a planetary gear meshing with a ring gear provided in accordance with an exemplary embodiment of the present invention; Figure 9 An image of a frequency domain simulation signal of a broken tooth of a planetary gear meshing with a ring gear provided in accordance with an exemplary embodiment of the present invention; Figure 10 A time domain image of a vibration signal in a healthy state provided by an exemplary embodiment of the present invention; Figure 11 A frequency domain image of a vibration signal in a healthy state provided by an exemplary embodiment of the present invention; Figure 12 A time domain image of a vibration signal when a sun gear tooth is broken is provided as an exemplary embodiment of the present invention; Figure 13 A frequency domain image of a vibration signal when a sun gear tooth is broken is provided as an exemplary embodiment of the present invention; Figure 14 A frequency domain amplified image of a vibration signal when a sun gear tooth is broken provided by an exemplary embodiment of the present invention; Figure 15 A time domain image of a vibration signal when a planetary gear meshing with a sun gear breaks a tooth, provided as an exemplary embodiment of the present invention Figure 16 Frequency domain image of the vibration signal when a planetary gear meshing with the sun gear breaks a tooth, provided as an exemplary embodiment of the present invention Figure 17 A frequency domain amplified image of a vibration signal when a tooth of a planetary gear meshing with a sun gear breaks, provided as an exemplary embodiment of the present invention; Figure 18 A time domain image of a vibration signal when a planetary gear meshing with a ring gear breaks a tooth, provided as an exemplary embodiment of the present invention Figure 19 Frequency domain image of the vibration signal when a planetary gear meshing with a ring gear breaks a tooth, provided as an exemplary embodiment of the present invention Figure 20 A frequency domain amplified image of a vibration signal when a tooth of a planetary gear meshing with a ring gear breaks, provided as an exemplary embodiment of the present invention; Figure 21A schematic diagram of a local fault diagnosis system for a double-row planetary gear according to an exemplary embodiment of the present invention; Figure 22 A schematic diagram of a computer device is provided for an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0021] This implementation proposes a local fault diagnosis method for a double-row planetary gear, wherein the sun gear meshes with each planet gear in the first row, the planet gears in the first row mesh with the corresponding planet gears in the second row, and the planet gears in the second row mesh with the ring gear, including the following process: S101: Performing a fault simulation based on the operating parameters of the double-row planetary gears and a sun gear tooth-breaking phenomenological model to obtain a first time domain image and a first frequency domain image. When a first modulated harmonic appears within a set frequency range before and after the meshing frequency in the first frequency domain image, and an impact with a first set period interval exists in the first time domain image, a sun gear tooth-breaking fault is determined to exist. S102: performing a fault simulation based on the operating parameters of the double-row planetary gears and a phenomenological model of a broken tooth of a planetary gear meshing with the sun gear to obtain a second time domain image and a second frequency domain image. When a second modulated harmonic appears within a set frequency range before and after the meshing frequency in the second frequency domain image, and an impact with a second set period interval exists in the second time domain image, it is determined that the planetary gear meshing with the sun gear is faulty. S103: A fault simulation is performed based on the operating parameters of the double-row planetary gears and a phenomenological model of a broken tooth of a planetary gear meshing with the ring gear to obtain a third time domain image and a third frequency domain image. When a third modulated harmonic appears within a set frequency range before and after the meshing frequency in the third frequency domain image, and an impact with a third set period interval exists in the third time domain image, it is determined that the planetary gear meshing with the ring gear is faulty.

[0022] Use a periodic function with meshing frequency as the fundamental frequency to simulate the gear system vibration signal model under fault-free conditions, and use a periodic rectangular window function The amplitude of the normal vibration signal is modulated to obtain the phenomenological model of the vibration signal under the gear pair broken tooth fault state: (1); (2); (3); Where, is the vibration signal model expression under fault conditions, is the meshing harmonic number, Basic meshing frequency ,in, is the number of teeth, is the rotation frequency of the faulty gear, and are the amplitude and initial phase; is the periodic rectangular window fault amplitude modulation function, Indicates the pulse train caused by a local fault; is the pulse amplitude; is the rotation period of the faulty gear, and the start / end time of each fault is ; is a periodic rectangular window function with an amplitude of 1.

[0023] In a double-row planetary gear system, Represents the sun gear, Indicates the first row of planetary gears that directly mesh with the sun gear, Indicates the sequence of planetary gears meshing with the sun gear; Indicates the second row of planetary gears meshing with the ring gear; Therefore, the meshing pair of sun gear-first row planet gear, the meshing pair of first row planet gear-second row planet gear, and the meshing pair of second row planet gear-ring gear can be expressed as 、 and ; 、 and Vibration generated by the meshing of a gear pair at the meshing point. 、 and It can be expressed as Vibration caused by meshing of gear pairs The time shift results of , and take into account their relative phase. Assuming that the same type of gear pairs have the same amplitude, 、 and It can be written as: (4); (5); (6); in, is the meshing harmonic number, where For the q The amplitude of the order meshing vibration; is the meshing frequency of the planetary gear train, is the meshing period of the planetary gear train, , is the initial phase of vibration of the reference meshing pair, For gear pair and Phase difference; For gear pair and Phase difference; For gear pair and Phase difference; for ; for and Phase difference.

[0024] Table 1 shows the simulation data used in the simulation signal, where it is assumed that different gear pairs have the same amplitude due to the floating ring gear arrangement.

[0025] Table 1: Simulation data

[0026] The time domain image in a healthy state is as follows Figure 2 As shown, the frequency domain image in a healthy state is as follows Figure 3 shown.

[0027] When a local failure occurs in the sun gear, The vibration of the gear pair will be modulated by the periodic pulses caused by the fault. and The vibration of the gear pair remains constant. The sun gear is fixed, so each The pulse repetition frequency generated by the gear pair fault is (planet carrier rotation frequency), that is, each The modulation frequency of the gear pair vibration is .

[0028] When a sun gear tooth breaks, assuming the faulty tooth is the initial meshing tooth, i.e. the first tooth, it only affects the teeth that are in direct contact with it. Gear pair, refer to the fault gear pair vibration signal model established by formula (1) to obtain the sun gear broken tooth phenomenological model: (7); (8); Where, For the sun gear - The vibration signal expression of a planetary gear meshing pair is: The vibration signal expression of all sun gear-planet gear meshing pairs (in the simulation process of the present invention, the number of double-row planet gears is 3), is the rotation frequency of the sun gear relative to the planet carrier, ; is the periodic rectangular window function when the sun gear fails. The specific expression is shown in formula (2). At this time, the rotation frequency of the faulty gear in formula (2) is for According to formula (8), the simulation experiment is carried out and the amplitude of the sun gear tooth fault is set as , which is shown in formula (2) , and the results are as follows Figure 4 and Figure 5 shown.

[0029] like Figure 4 As shown, the sun gear broken teeth mesh with three planetary gears (three are used as an example in this implementation) in sequence, with an interval time of , there are three sets of planetary gears , the sun wheel rotates one circle, and the faulty tooth meshes three times. The sun produces one shock every time it rotates, and three shocks every time it rotates. Figure 5 As shown, in the frequency domain image, the meshing frequency As the fundamental frequency, the meshing frequency harmonic components will be formed in the spectrum , at the meshing frequency There are planet carriers spaced on both sides to multiply the rotation frequency Modulation sideband This fault signature can be used to detect localized faults in the sun gear teeth.

[0030] When a tooth breakage occurs on the planetary gear meshing with the sun gear, only one planetary gear has a tooth breakage failure, and the other planetary gears are working normally. Planetary gears ( ) fails, and the faulty tooth is the initial meshing tooth, that is, the first tooth, affecting the sun gear in direct contact with it and the meshing pair with the second row of planetary gears. At the initial moment At this time, the faulty tooth just enters into meshing with the sun gear. The time interval from the start of meshing with the sun gear to the meshing with another planetary gear is , referring to the vibration signal model of the faulty gear pair established by formula (1), the phenomenological model of the broken tooth of the planetary gear meshing with the sun gear is obtained: (9); (10); (11); Where, For the The vibration signal expression of the sun gear-planet gear pair meshing with the sun gear is: Indicates the The vibration signal expression of the planet-planet meshing pair is: Indicates all gears with faults Expression of the vibration signal generated by a meshing gear pair. Represents the rotation frequency of the first row of planetary gears relative to the planet carrier, and is the periodic rectangular window function when the first row of planetary gears fails. The specific expression is shown in formula (2). At this time, the rotation frequency of the faulty gear in formula (2) is for According to formula (11), a simulation experiment is conducted, assuming The gear pair fault amplitude is 10, The gear pair fault amplitude is 5, which is shown in formula (2). , and the results are as follows Figure 6 and Figure 7 As shown. Figure 6 As shown in the time domain image, the sensor periodically receives two periodic pulse sequences with a time interval of 0.0213s; at the same time, the frequency domain image describes the modulation sideband around the meshing frequency as ,like Figure 7 As shown, the time domain interval characteristics and frequency domain sideband characteristics can be used to detect the broken tooth fault of the planetary gear meshing with the sun gear in the double-row planetary gear train.

[0031] When a tooth breakage occurs on a planetary gear meshing with the ring gear, only one planetary gear has a tooth breakage failure, and the other planetary gears are working normally. Planetary gears ( ) fails, assuming that the faulty tooth is the initial meshing tooth, that is, the first tooth, affecting the gear ring in direct contact with it and the meshing pair with the first row of planetary gears. At the initial moment At this time, the faulty tooth just enters into meshing with the first row of planetary gears. The time interval from the start of meshing with the first row of planetary gears to the meshing with the ring gear is Referring to the vibration signal model of the faulty gear pair established by formula (1), the phenomenological model of the broken tooth of the planetary gear meshing with the ring gear is obtained: (12); (13); (14); Where, For the The vibration signal expression of the planet-planet meshing pair is: Indicates the The vibration signal expression of the planetary gear-ring gear meshing pair is: Indicates all faulty gears Expression of the vibration signal generated by a meshing gear pair. is the rotational frequency of the second row of planetary gears relative to the planet carrier. and is the periodic rectangular window function when the second row of planetary gears fails. The specific expression is shown in formula (2). At this time, the rotation frequency of the faulty gear in formula (2) is for According to formula (14), a simulation experiment is conducted, assuming The gear pair fault amplitude is 10, The gear pair fault amplitude is 5, which is shown in formula (2). , and the results are as follows Figure 8 and Figure 9 shown.

[0032] like Figure 8 As shown in the time domain image, the sensor periodically receives two periodic pulse sequences with a time interval of 0.0340s; at the same time, the frequency domain image describes the modulation sideband around the meshing frequency as ,like Figure 9 As shown, the time domain interval characteristics and frequency domain sideband characteristics can be used to detect the broken tooth fault of the planetary gear meshing with the ring gear in the double-row planetary gear train.

[0033] In order to verify the validity of the established vibration model and theoretical derivation, four sets of experiments were conducted on the test bench. The test bench consists of a drive motor, a load motor and a two-stage planetary gearbox with a reduction ratio of 2.08. The first stage of the two-stage planetary gearbox consists of a sun gear. , planetary gears and ring gear The number of teeth is 30, 21 and 72 respectively. The second stage of the double-stage planetary gearbox includes the sun gear , planetary gears , planetary gears and ring gear , the number of teeth are 、 and .

[0034] The signal collected in the healthy state is the base frequency signal. Then, the faults in the following cases are studied: Case 1: Sun gear tooth breakage; Case 2: First row planetary gear Broken teeth; Case 3: Second row of planetary gears Broken teeth.

[0035] During the experiment, the input shaft connected to the sun gear was set at 700 rpm, and the output shaft connected to the planetary carrier was loaded with 200 Nm. The vibration signal was measured by a triaxial accelerometer mounted on the gearbox housing with a sampling frequency of 5120 Hz and a duration of 10 minutes.

[0036] According to the transmission mechanism of the two-stage planetary gearbox, the speed characteristic equation of the two-stage gear train is: (15); (16); According to formulas (15) and (16), substituting The actual rotation frequency , The actual rotation frequency and = (The two-stage gear train has different numbers of ring teeth but the same speed. The ring gear is an integrated structure, and only the number of teeth of the ring gears at different stages is different.) The absolute rotation frequency, relative rotation frequency, and meshing frequency of each stage of the experimental gearbox were calculated, as shown in Table 2.

[0037] Table 2: Speed ​​and meshing frequency of each gearbox component

[0038] The vibration signal of the gearbox in a healthy state is analyzed as a reference signal for comparison and analysis with the experimental signal of subsequent broken tooth fault. The reference signal is measured when all gears are in a healthy state. Figure 10 and Figure 11 A time domain plot of the reference signal and a frequency domain plot of the response are shown.

[0039] pass Figure 10 and Figure 11 It can be seen that the spectrum lines with larger amplitudes in the actual spectrum are mainly at the meshing frequency and its multiples. The actual meshing frequency is basically consistent with the theoretical meshing frequency. The second-order meshing frequency is approximately 182Hz, and its multiples are These phenomena are generally consistent with the simulation results, thus verifying the accuracy and correctness of the model. Due to inevitable manufacturing and installation errors and noise interference, some irregular, low-amplitude sidebands appear in the spectrum. Furthermore, due to the complex structure of the gearbox, which includes rotating components such as shafts, bearings, and other gear transmission systems in addition to the ones studied in this article, the test spectrum also contains other spectral lines with larger amplitudes.

[0040] (1) The sun gear has broken teeth.

[0041] Figure 12 、 Figure 13 and Figure 14 The time domain image, frequency domain image and frequency domain image magnification of the vibration signal of the two-stage planetary gearbox when the sun gear is broken are shown respectively. Figure 13 The time domain diagram of the vibration signal is the same as the model prediction. The cycle of repeated shocks. Figure 14 This is the frequency domain diagram of the vibration signal. The sidebands of the vibration signal in the fault state are much richer than the baseline signal. Figure 15 This is the frequency domain magnified waveform of the vibration signal. Modulation sidebands, corresponding to meshing harmonics in simulations There are modulation sidebands on both sides of the sun gear relative rotation frequency ,The vibration law derived from this phenomenon is consistent with the ,theoretical deduction, thus verifying the accuracy of the model.

[0042] The present invention analyzes the experimental images of the broken teeth of the double-row planetary gears meshing with the sun gear and the broken teeth of the planetary gears meshing with the ring gear, compares the time domain impact time interval and frequency domain vibration frequency law obtained in the images with the simulation experimental results, and verifies the reliability of the model.

[0043] (2) Planetary gears meshing with the sun gear Broken teeth situation.

[0044] Figure 15 、 Figure 16 and Figure 17 These respectively represent the time domain image, frequency domain image, and frequency domain magnified waveform image of the vibration signal when the planetary gear (first row of planetary gears) meshing with the sun gear breaks a tooth. Figure 16 The time domain waveform of the field test signal under the condition of broken teeth of the planetary gear is shown. It can be seen from the figure that the period is about The two periodic pulse sequences correspond to the time it takes for the second-stage planetary gear to rotate one circle relative to the planetary carrier, that is, the two periodic pulse frequencies are , the period is ; Two adjacent shocks appear periodically in the time domain signal, with a time interval of approximately , which corresponds to the time interval between the broken tooth position of the planetary gear and the sequential meshing of the paired sun gear and the second row of planetary gears, that is, . Figure 17 The spectrum of the vibration signal when a tooth of a planetary gear meshing with the sun gear breaks is shown. Figure 18 The enlarged waveform of the vibration signal when the planetary gear meshing with the sun gear breaks is shown. Modulation sidebands, corresponding to meshing harmonics in simulations There are modulation sidebands on both sides of the relative rotation frequency of the first row of planetary gears .

[0045] (3) Planetary gear meshing with the ring gear Broken teeth situation.

[0046] Figure 18 、 Figure 19 and Figure 20 These respectively represent the time domain, frequency domain, and frequency domain magnified waveform images of the vibration signal when the planetary gear meshing with the ring gear (i.e., the second row of planetary gears) breaks its teeth. Figure 19 The time domain waveform of the field test signal under the condition of broken teeth of the second-stage planetary gear meshing with the sun gear is shown. It can be seen from the figure that the period is about The two periodic pulse sequences correspond to the time it takes for the second row of planetary gears to rotate one circle relative to the planet carrier, that is, the two periodic pulse frequencies are , the period is ; Two adjacent shocks appear periodically in the time domain signal, with a time interval of approximately , which corresponds to the time interval between the broken tooth position of the planetary gear and the sequential meshing of the first row of paired planetary gears and the ring gear, that is, . Figure 20 The spectrum of the vibration signal when a planetary gear meshing with the ring gear breaks is shown. Figure 21 The enlarged waveform of the vibration signal when the planetary gear meshing with the ring gear breaks is shown. Modulation sidebands, corresponding to meshing harmonics in simulations There are modulation sidebands on both sides of the relative rotation frequency of the first row of planetary gears .

[0047] Since the second stage planetary gear and planetary gears The theoretical calculated values ​​of the rotation time and fault characteristic frequency relative to the planet carrier are the same, so it is impossible to accurately determine whether the damaged gear tooth appears in the planet gear from the envelope spectrum or Fourier spectrum. , or planetary gear However, the time interval characteristics of adjacent impact components extracted from the time domain signal, that is, the time intervals of the fault teeth on different gears are different ( and ), it can be determined that the damaged gear teeth appear on the planetary gear On or In fact, the vibration law derived from this phenomenon is consistent with the theoretical deduction, thus verifying the accuracy of the model.

[0048] In summary, the present invention proposes the vibration laws of different types of faults: Vibration law of sun gear failure: Vibration frequency domain image at meshing frequency There are planetary gears with a spacing of Harmonics ( is the number of planetary gears), fault characteristic frequency , there is a time interval in the time domain image The impact; Vibration law of the planetary gear meshing with the sun gear (i.e. the first row of planetary gears) when it fails: The vibration frequency domain image is at the meshing frequency The relative rotation frequency of the planetary gear with a spacing of Modulation harmonics, i.e. fault characteristic frequencies , there is a time interval in the time domain image of The fault modulation frequency is the same as that of the sun gear and the second row of planetary gears. ; In the time domain image, the time interval between two groups of shocks is: (17); in, (18); (19); is the base tooth thickness of the planetary gear, for Gear pair and The angle between the centers of the gear pairs, is the pressure angle, are the base circle radius and the top circle radius of the first row of planetary gears respectively, The gear pair represents the sun gear and the first row of planetary gears. A gear pair consisting of planetary gears, The gear pair represents the first row of planetary gears. The first planetary gear and the second planetary gear A gear pair consisting of planetary gears, 、 and They represent the center of the sun gear, the first row of planetary gears, The center of the first planetary gear and the first planetary gear in the second row The center of the planetary gear.

[0049] Vibration law of the planetary gear meshing with the ring gear (i.e. the second row of planetary gears) when it fails: the vibration frequency domain image at the meshing frequency The relative rotation frequency of the planetary gear with a spacing of Modulation harmonics, i.e. fault characteristic frequencies , there is a time interval in the time domain image of Since the faulty tooth is meshed with the ring gear and the first row of planetary gears respectively, the fault modulation frequency is the same as ; In the time domain image, the time interval between two groups of shocks is: (20); in, (twenty one); (twenty two); is the base tooth thickness of the planetary gear, for Gear pair and The angle between the lines connecting the centers of the circles, is the pressure angle, are the planetary gear base circle radius and tooth tip circle radius respectively; are the base circle radius of the gear ring and the top circle radius of the gear, The gear pair represents the ring gear and the second row of planetary gears. A gear pair consisting of planetary gears, The gear pair represents the first row of planetary gears. The first planetary gear and the second planetary gear A gear pair consisting of planetary gears, 、 and Represents the center of the ring gear, the first row of planetary gears The center of the first planetary gear and the first planetary gear in the second row The centers of the planetary gears, the ring gear, and the sun gear are all .

[0050] Figure 21 A local fault diagnosis system for double-row planetary gears is proposed, including: The sun gear tooth breakage identification unit 2101 is configured to: perform fault simulation based on the operating parameters of the double-row planetary gears and the sun gear tooth breakage phenomenological model to obtain a first time domain image and a first frequency domain image; and determine that a sun gear tooth breakage fault exists when a first modulated harmonic appears within a set frequency range before and after the meshing frequency in the first frequency domain image, and an impact with a first set period interval exists in the first time domain image; The first planetary gear broken tooth identification unit 2102 is configured to: perform a fault simulation based on the operating parameters of the double-row planetary gears and a phenomenological model of a broken tooth of a planetary gear meshing with the sun gear, obtain a second time domain image and a second frequency domain image, and determine that a planetary gear meshing with the sun gear is faulty when a second modulated harmonic appears within a set frequency range before and after the meshing frequency in the second frequency domain image, and an impact with a second set period interval exists in the second time domain image; The second planetary gear broken tooth identification unit 2103 is configured as: a time domain image and a third frequency domain image. When a third modulated harmonic appears within a set frequency range before and after the meshing frequency in the third frequency domain image, and an impact with a third set period interval exists in the third time domain image, it is determined that the planetary gear meshing with the ring gear is faulty.

[0051] It is understandable that each of the above-mentioned units can be separately or completely combined into one or several other units to form a unit, or one (or some) of the units can be further divided into multiple functionally smaller units to form a unit, which can achieve the same operation without affecting the realization of the technical effects of the embodiments of the present application. The above-mentioned units are divided based on logical functions. In actual applications, the functions of one unit can also be implemented by multiple units, or the functions of multiple units can be implemented by one unit. In other embodiments of the present application, the system may also include other units. In actual applications, these functions can also be implemented with the assistance of other units and can be implemented by the collaboration of multiple units.

[0052] According to another embodiment of the present application, the system described in this embodiment can be constructed by running a computer program (including program code) capable of executing the steps involved in the corresponding method of the present invention on a general-purpose computing device such as a computer, which includes processing elements and storage elements such as a central processing unit (CPU), random access memory (RAM), and read-only memory (ROM). The computer program can be recorded on, for example, a computer-readable recording medium, and loaded into the above-mentioned computing device through the computer-readable recording medium and run therein.

[0053] Figure 22 A computer device is shown, which includes a processor 2201, a communication interface 2202, and a computer-readable storage medium 2203. The processor 2201, the communication interface 2202, and the computer-readable storage medium 2203 may be connected via a bus or other means.

[0054] Among them, the communication interface 2202 is used to receive and send data, the computer-readable storage medium 2203 can be stored in the memory of the electronic device, the computer-readable storage medium 2203 is used to store computer programs, the computer programs include program instructions, and the processor 2201 is used to execute the program instructions stored in the computer-readable storage medium 2203.

[0055] The processor 2201 is the computing core and control core of the electronic device, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions to implement corresponding method processes or corresponding functions.

[0056] The processor 2201 is configured to perform the following process: A fault simulation is performed based on the operating parameters of the double-row planetary gears and the sun gear tooth-breaking phenomenological model to obtain a first time domain image and a first frequency domain image. When a first modulated harmonic appears within a set frequency range before and after the meshing frequency in the first frequency domain image, and an impact with a first set period interval exists in the first time domain image, a sun gear tooth-breaking fault is determined to be present. A fault simulation is performed based on the operating parameters of the double-row planetary gears and a phenomenological model of a broken tooth of a planetary gear meshing with the sun gear, to obtain a second time domain image and a second frequency domain image. When a second modulated harmonic appears within a set frequency range before and after the meshing frequency in the second frequency domain image, and an impact with a second set period interval is present in the second time domain image, a fault is determined in the planetary gear meshing with the sun gear. A fault simulation is performed based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken tooth of the planetary gear meshing with the ring gear. A third time domain image and a third frequency domain image are obtained. When a third modulated harmonic appears within a set frequency range before and after the meshing frequency in the third frequency domain image, and an impact with a third set period interval exists in the third time domain image, a fault is determined to be present in the planetary gear meshing with the ring gear.

[0057] The present invention also provides a computer-readable storage medium, which is a memory device in an electronic device for storing programs and data. It is understood that the computer-readable storage medium herein may include both built-in storage media in the electronic device and, of course, extended storage media supported by the electronic device. The computer-readable storage medium provides storage space that stores the processing system of the electronic device.

[0058] Furthermore, the storage space also stores one or more instructions suitable for being loaded and executed by the processor. These instructions may be one or more computer programs (including program code). It should be noted that the computer-readable storage medium herein may be a high-speed RAM memory or a non-volatile memory, such as at least one disk storage device; alternatively, it may be at least one computer-readable storage medium located remotely from the processor.

[0059] In one embodiment, the computer-readable storage medium stores one or more instructions; the processor loads and executes the one or more instructions stored in the computer-readable storage medium to implement the following process: A fault simulation is performed based on the operating parameters of the double-row planetary gears and the sun gear tooth-breaking phenomenological model to obtain a first time domain image and a first frequency domain image. When a first modulated harmonic appears within a set frequency range before and after the meshing frequency in the first frequency domain image, and an impact with a first set period interval exists in the first time domain image, a sun gear tooth-breaking fault is determined to be present. A fault simulation is performed based on the operating parameters of the double-row planetary gears and a phenomenological model of a broken tooth of a planetary gear meshing with the sun gear, to obtain a second time domain image and a second frequency domain image. When a second modulated harmonic appears within a set frequency range before and after the meshing frequency in the second frequency domain image, and an impact with a second set period interval is present in the second time domain image, a fault is determined in the planetary gear meshing with the sun gear. A fault simulation is performed based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken tooth of the planetary gear meshing with the ring gear. A third time domain image and a third frequency domain image are obtained. When a third modulated harmonic appears within a set frequency range before and after the meshing frequency in the third frequency domain image, and an impact with a third set period interval exists in the third time domain image, a fault is determined to be present in the planetary gear meshing with the ring gear.

[0060] The present invention also provides a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of an electronic device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the electronic device to perform the following process: A fault simulation is performed based on the operating parameters of the double-row planetary gears and the sun gear tooth-breaking phenomenological model to obtain a first time domain image and a first frequency domain image. When a first modulated harmonic appears within a set frequency range before and after the meshing frequency in the first frequency domain image, and an impact with a first set period interval exists in the first time domain image, a sun gear tooth-breaking fault is determined to be present. A fault simulation is performed based on the operating parameters of the double-row planetary gears and a phenomenological model of a broken tooth of a planetary gear meshing with the sun gear, to obtain a second time domain image and a second frequency domain image. When a second modulated harmonic appears within a set frequency range before and after the meshing frequency in the second frequency domain image, and an impact with a second set period interval is present in the second time domain image, a fault is determined in the planetary gear meshing with the sun gear. A fault simulation is performed based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken tooth of the planetary gear meshing with the ring gear. A third time domain image and a third frequency domain image are obtained. When a third modulated harmonic appears within a set frequency range before and after the meshing frequency in the third frequency domain image, and an impact with a third set period interval exists in the third time domain image, a fault is determined to be present in the planetary gear meshing with the ring gear.

[0061] Those skilled in the art will appreciate that the units and algorithmic steps of each example described in conjunction with the embodiments disclosed in this application can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional technical personnel may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0062] The above embodiments can be implemented in whole or in part using software, hardware, firmware, or any combination thereof. When implemented using software, they can be implemented in whole or in part in the form of a computer program product. A computer program product comprises one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions according to the embodiments of the present application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted via a computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, optical fiber, digital line) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that can be accessed by a computer, or a data processing device such as a server or data center that integrates one or more available media. Available media can include magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state drives).

[0063] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A local fault diagnosis method for a double-row planetary gear, characterized in that: The following processes are included: A fault simulation is performed based on the operating parameters of the double-row planetary gears and the sun gear tooth-breaking phenomenological model to obtain a first time domain image and a first frequency domain image. When a first modulated harmonic appears within a set frequency range before and after the meshing frequency in the first frequency domain image, and an impact with a first set period interval exists in the first time domain image, a sun gear tooth-breaking fault is determined to be present. A fault simulation is performed based on the operating parameters of the double-row planetary gears and a phenomenological model of a broken tooth of a planetary gear meshing with the sun gear, to obtain a second time domain image and a second frequency domain image. When a second modulated harmonic appears within a set frequency range before and after the meshing frequency in the second frequency domain image, and an impact with a second set period interval is present in the second time domain image, a fault is determined in the planetary gear meshing with the sun gear. A fault simulation is performed based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken tooth of the planetary gear meshing with the ring gear. A third time domain image and a third frequency domain image are obtained. When a third modulated harmonic appears within a set frequency range before and after the meshing frequency in the third frequency domain image, and an impact with a third set period interval exists in the third time domain image, a fault is determined to be present in the planetary gear meshing with the ring gear.

2. The local fault diagnosis method of a double-row planetary gear according to claim 1, characterized in that: When the first modulation harmonic appears in the set frequency range before and after the meshing frequency in the first frequency domain image, the fault harmonic for: ,in, represents the planet carrier rotation frequency, represents the meshing frequency, Represents the number of planetary gears meshing with the sun gear; The first set cycle interval is: .

3. The local fault diagnosis method of a double-row planetary gear according to claim 1, characterized in that: When the second modulation harmonic appears in the set frequency range before and after the meshing frequency in the second frequency domain image, the fault harmonic for: , represents the meshing frequency, Represents the relative rotation frequency of the planet gear meshing with the sun gear relative to the planet carrier; The second set cycle interval is: .

4. The local fault diagnosis method of a double-row planetary gear according to claim 1, characterized in that: When the third modulation harmonic appears in the set frequency range before and after the meshing frequency in the third frequency domain image, the fault harmonic for: , represents the meshing frequency, Represents the relative rotation frequency of the planet gear meshing with the sun gear relative to the planet carrier; The third set cycle interval is: .

5. The local fault diagnosis method of a double-row planetary gear according to claim 1, characterized in that: Sun gear broken tooth phenomenological model for: ,in, Represents the sun gear- The vibration signal expression of a planetary gear meshing pair is: Represents the number of planetary gears meshing with the sun gear, It is calculated based on the operating parameters and fault modulation mechanism of the double-row planetary gear.

6. The local fault diagnosis method of a double-row planetary gear according to claim 1, characterized in that: Phenomenological model of broken teeth of planetary gear meshing with sun gear for: ,in, Representative The vibration signal expression of the sun gear-planet gear pair meshing with the sun gear is: Represents the number of planetary gears meshing with the sun gear, Representative The vibration signal expression of the planet-planet meshing pair is: and It is calculated based on the operating parameters and fault modulation mechanism of the double-row planetary gear.

7. The local fault diagnosis method of a double-row planetary gear according to claim 1, characterized in that: Phenomenological model of broken teeth of planetary gear meshing with ring gear for: ,in, Represents the number of planetary gears meshing with the sun gear, Representative The vibration signal expression of the planet-planet meshing pair is: Indicates the The vibration signal expression of the planetary gear-ring gear meshing pair is: and It is calculated based on the operating parameters and fault modulation mechanism of the double-row planetary gear.

8. A local fault diagnosis system for double-row planetary gears, characterized in that: include: The sun gear tooth breakage identification unit is configured to: perform fault simulation based on the operating parameters of the double-row planetary gears and the sun gear tooth breakage phenomenological model to obtain a first time domain image and a first frequency domain image; and determine that a sun gear tooth breakage fault exists when a first modulated harmonic appears within a set frequency range before and after the meshing frequency in the first frequency domain image, and an impact with a first set period interval exists in the first time domain image; The first planetary gear broken tooth identification unit is configured to: perform a fault simulation based on the operating parameters of the double-row planetary gears and a phenomenological model of a broken tooth of a planetary gear meshing with the sun gear, obtain a second time domain image and a second frequency domain image, and determine that a planetary gear meshing with the sun gear is faulty when a second modulated harmonic appears within a set frequency range before and after the meshing frequency in the second frequency domain image, and an impact with a second set period interval exists in the second time domain image; The second planetary gear broken tooth identification unit is configured to: perform fault simulation based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken teeth of the planetary gear meshing with the ring gear, obtain a third time domain image and a third frequency domain image, and when a third modulated harmonic appears within a set frequency range before and after the meshing frequency in the third frequency domain image, and an impact of a third set period interval exists in the third time domain image, it is determined that the planetary gear meshing with the ring gear is faulty.

9. A computer device, characterized in that: include: a processor and a computer-readable storage medium; a processor adapted to execute a computer program; A computer-readable storage medium having a computer program stored therein, wherein when the computer program is executed by the processor, the local fault diagnosis method for the double-row planetary gear according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and the computer program is suitable for being loaded by a processor and executing the local fault diagnosis method for a double-row planetary gear according to any one of claims 1 to 7.

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