Method and system for partial fault diagnosis of double-row planetary gears

Abstract

The application belongs to the technical field of fault diagnosis. A local fault diagnosis method and system of double-row planetary gear are provided, and various broken tooth phenomenological models are constructed. Through the fault simulation of these models, the state of different component broken teeth can be comprehensively and meticulously analyzed, the fault identification is more targeted and accurate, the rapid identification of sun gear broken teeth and planetary gear broken teeth is realized, the fault can be detected in time, the more serious equipment damage caused by fault delay is avoided, the maintenance cost and downtime are effectively reduced, the operation efficiency of the equipment is improved, through the analysis of the characteristics of the modulation harmonic and the impact in the time domain image and the frequency domain image, whether the fault exists and the specific position of the fault can be accurately determined, the misdiagnosis and missed diagnosis are reduced, reliable basis is provided for subsequent maintenance work, and the technical blank of double-row planetary gear fault identification is filled.

Description

Technical Field

[0001] This invention relates to the field of fault diagnosis technology, and specifically to a method and system for diagnosing local faults in a double-row planetary gear. Background Technology

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

[0003] Planetary gear systems are widely used in critical fields such as automotive transmissions, wind power equipment, and aerospace due to their high power density and compact structure. In recent years, the Dual-Row Serially Connected Planetary Gear (DRSCPG) has gradually become the preferred solution for multi-stage speed change and high-transmission-efficiency mechanical systems due to its unique power transmission path of a single sun gear, two planetary gears in series, and a ring gear, which offers higher transmission ratios and greater layout flexibility. 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 in a double-row planetary gear train can lead to system failure and serious consequences. The unique transmission path of a double-row planetary gear train—single sun gear-double-row planetary gear series-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 double-row structures, the manifestation of fault characteristics differs greatly from that of single-row structures. Traditional signal processing and analysis techniques are difficult to accurately extract the characteristic information of tooth breakage faults in double-row planetary gear trains, resulting in the inability to effectively identify the fault. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method and system for diagnosing local faults in double-row planetary gears. It constructs a phenomenological model of broken teeth on the sun gear (a model describing the phenomenon based on observation and experimental data), a phenomenological model of broken teeth on the first row of planetary gears (planetary gears meshing with the sun gear), and a phenomenological model of broken teeth on the second row of planetary gears (planetary gears meshing with the gear ring). This enables rapid identification of broken teeth on the sun gear, the first row of planetary gears, and the second row of planetary gears, greatly improving the accuracy of fault diagnosis.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for diagnosing local faults in a double-row planetary gear.

[0008] A method for diagnosing local faults in a double-row planetary gear system includes the following steps:

[0009] Based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken sun gear tooth, a fault simulation is performed to obtain a first time domain image and a first frequency domain image. When a first modulation 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, it is determined that there is a broken sun gear tooth fault.

[0010] Based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken teeth of the planetary gears meshing with the sun gear, a fault simulation is performed to obtain a second time-domain image and a second frequency-domain image. When a second modulation harmonic appears within a set frequency range before and after the meshing frequency in the second frequency-domain image, and there is an impact with a second set period interval in the second time-domain image, the fault of the planetary gear meshing with the sun gear is determined.

[0011] Based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken teeth of the planetary gears meshing with the gear ring, a fault simulation is performed to obtain a third time-domain image and a third frequency-domain image. When a third modulation 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, the fault of the planetary gear meshing with the gear ring is determined.

[0012] Secondly, the present invention provides a local fault diagnosis system for double-row planetary gears.

[0013] A partial fault diagnosis system for a double-row planetary gear includes:

[0014] 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 phenomenological model of sun gear tooth breakage to obtain a first time domain image and a first frequency domain image; when a first modulation harmonic appears within a set frequency range before and after the meshing frequency in the first frequency domain image, and there is an impact with a first set period interval in the first time domain image, it is determined that there is a sun gear tooth breakage fault.

[0015] The first planetary gear tooth breakage 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 planetary gear meshing with the sun gear to obtain a second time-domain image and a second frequency-domain image; when a second modulation harmonic appears within a set frequency range before and after the meshing frequency in the second frequency-domain image, and there is an impact with a second set period interval in the second time-domain image, the planetary gear meshing with the sun gear is determined to be faulty.

[0016] The second planetary gear tooth breakage 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 planetary gear meshing with the gear ring to obtain a third time-domain image and a third frequency-domain image; when a third modulation 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, the planetary gear meshing with the gear ring is determined to be faulty.

[0017] Thirdly, the present invention provides a computer device, comprising: a processor and a computer-readable storage medium;

[0018] A processor, adapted to execute computer programs;

[0019] A computer-readable storage medium storing a computer program, which, when executed by the processor, implements the partial fault diagnosis method for double-row planetary gears as described in the first aspect of the present invention.

[0020] Fourthly, the present invention provides a computer-readable storage medium storing a computer program adapted to be loaded by a processor and executed as described in the first aspect of the present invention for local fault diagnosis of a double-row planetary gear.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] This invention innovatively proposes a local fault diagnosis method for double-row planetary gears, constructing multiple phenomenological models of broken teeth, covering the sun gear, the planetary gear meshing with the sun gear, and the planetary gear meshing with the ring gear. This provides a precise theoretical basis for fault diagnosis. By simulating faults using these models, the state of different components when teeth are broken can be analyzed comprehensively and meticulously, making fault identification more targeted and accurate. It enables rapid identification of broken teeth on the sun gear and planetary gears, allowing for timely detection of faults and preventing more serious equipment damage due to fault delays. This effectively reduces maintenance costs and downtime, improves equipment operating efficiency, and by analyzing the characteristics of modulation harmonics and impulses in time-domain and frequency-domain images, the existence and specific location of the fault can be accurately determined, reducing misdiagnosis and missed diagnosis. This provides a reliable basis for subsequent maintenance work, fills the technical gap in fault identification for double-row planetary gears, and helps improve the reliability and stability of double-row planetary gear systems, ensuring the safe operation of equipment in key fields such as automotive transmissions, wind power, and aerospace.

[0023] When identifying broken teeth on the sun gear, this invention clarifies the relationship between fault harmonics and meshing frequency, planet carrier rotation frequency, and the number of planet gears meshing with the sun gear. This provides a clear theoretical basis for fault determination. When a first modulation harmonic conforming to the expression appears within a set frequency range before and after the meshing frequency in the first frequency domain image, and an impact with a corresponding set period interval exists in the first time domain image, a broken tooth fault on the sun gear can be accurately determined. The same principle applies to the determination of broken tooth faults on the other two rows of planet gears. This makes fault diagnosis no longer dependent on fuzzy empirical judgments, but 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.

[0024] When identifying broken teeth on planetary gears meshing with the sun gear, the relationship between fault harmonics and meshing frequencies, as well as the relative rotational frequency of the planetary gear meshing with the sun gear relative to the planet carrier, was defined. This laid a solid theoretical foundation for fault diagnosis, such as broken teeth on planetary gears meshing with the sun gear. When a second modulation harmonic conforming to this expression appears within a set frequency range before and after the meshing frequency in the second frequency domain image, and the second time domain image has a corresponding set periodic interval impact, a broken tooth fault on a planetary gear meshing with the sun gear can be accurately determined. Fault diagnosis for other rows of planetary gears can be deduced similarly. This provides a precise quantitative standard for fault diagnosis, greatly improving the accuracy and scientific rigor of the diagnosis, effectively avoiding misdiagnosis and missed diagnosis caused by subjective judgment, ensuring the stable operation of the double-row planetary gear system, and reducing equipment failure risks and maintenance costs.

[0025] When identifying broken teeth on planetary gears meshing with the ring gear, a correlation was established between fault harmonics and meshing frequencies, as well as the relative rotational frequencies of planetary gears meshing with the sun gear relative to the planet carrier. This provides rigorous theoretical support for fault diagnosis. When a third modulation harmonic conforming to this expression appears within a set frequency range before and after the meshing frequency in the third frequency domain image, and a corresponding set periodic interval impact exists in the third time domain image, the broken tooth fault on the planetary gear meshing with the ring gear can be accurately determined. Other fault diagnoses can also refer to this logic. This greatly improves the accuracy and reliability of fault diagnosis, makes the diagnostic process systematic, effectively avoids errors caused by subjective assumptions, helps to detect faults in a timely manner, ensures the stable and efficient operation of the double-row planetary gear system, and reduces the risks and losses caused by equipment failures.

[0026] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0027] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0028] Figure 1 A flowchart illustrating a method for diagnosing local faults in a double-row planetary gear according to an exemplary embodiment of the present invention;

[0029] Figure 2 A time-domain image of a health status signal provided as an exemplary embodiment of the present invention;

[0030] Figure 3 A frequency domain image of a health status signal provided as an exemplary embodiment of the present invention;

[0031] Figure 4 A time-domain simulated signal image of a broken sun gear tooth provided as an exemplary embodiment of the present invention;

[0032] Figure 5 A frequency domain analog signal image of a broken sun gear tooth provided as an exemplary embodiment of the present invention;

[0033] Figure 6 A time-domain simulated signal image of a broken tooth of a planetary gear meshing with a sun gear, provided as an exemplary embodiment of the present invention;

[0034] Figure 7 A frequency domain analog signal image of a planetary gear tooth breakage in mesh with the sun gear, provided as an exemplary embodiment of the present invention;

[0035] Figure 8 A time-domain simulated signal image of a planetary gear tooth breakage in mesh with a gear ring, provided as an exemplary embodiment of the present invention;

[0036] Figure 9 A frequency domain analog signal image of a planetary gear tooth breakage in mesh with a gear ring, provided as an exemplary embodiment of the present invention;

[0037] Figure 10 A time-domain image of vibration signals in a healthy state, provided as an exemplary embodiment of the present invention;

[0038] Figure 11 A frequency domain image of a vibration signal in a healthy state, provided as an exemplary embodiment of the present invention;

[0039] Figure 12 A time-domain image of the vibration signal when a sun gear tooth breaks, provided as an exemplary embodiment of the present invention;

[0040] Figure 13 A frequency domain image of the vibration signal when a sun gear tooth breaks, provided as an exemplary embodiment of the present invention;

[0041] Figure 14 A frequency domain magnified image of the vibration signal when a sun gear tooth breaks, provided as an exemplary embodiment of the present invention;

[0042] Figure 15 A time-domain image of the vibration signal when a planetary gear meshing with the sun gear breaks, provided as an exemplary embodiment of the present invention.

[0043] Figure 16 Frequency domain image of vibration signal when a planetary gear meshing with the sun gear breaks, provided as an exemplary embodiment of the present invention.

[0044] Figure 17 A frequency domain magnified 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;

[0045] Figure 18 A time-domain image of the vibration signal when a planetary gear meshing with a gear ring breaks, provided as an exemplary embodiment of the present invention.

[0046] Figure 19 Frequency domain image of vibration signal when a planetary gear meshing with a gear ring breaks, provided as an exemplary embodiment of the present invention.

[0047] Figure 20 A frequency domain magnified image of the vibration signal when a planetary gear meshing with a gear ring breaks a tooth, provided as an exemplary embodiment of the present invention;

[0048] Figure 21 A schematic diagram of a partial fault diagnosis system for a double-row planetary gear provided as an exemplary embodiment of the present invention;

[0049] Figure 22 A schematic diagram of a computer device provided for an exemplary embodiment of the present invention. Detailed Implementation

[0050] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0051] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0052] This implementation proposes a method for diagnosing local faults in a double-row planetary gear system. The sun gear meshes with each planet gear in the first row, the first row of planet gears meshes with the corresponding planet gears in the second row, and the second row of planet gears meshes with the ring gear. The method includes the following processes:

[0053] S101: Based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken sun gear tooth, a fault simulation is performed to obtain a first time domain image and a first frequency domain image. When a first modulation 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, it is determined that there is a broken sun gear tooth fault.

[0054] S102: 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 sun gear, a fault simulation is performed to obtain a second time-domain image and a second frequency-domain image. When a second modulation harmonic appears within a set frequency range before and after the meshing frequency in the second frequency-domain image, and there is an impact with a second set period interval in the second time-domain image, the fault of the planetary gear meshing with the sun gear is determined.

[0055] S103: 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 gear ring, a fault simulation is performed to obtain a third time-domain image and a third frequency-domain image. When a third modulation 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, the fault of the planetary gear meshing with the gear ring is determined.

[0056] A periodic function with the meshing frequency as the fundamental frequency is used to simulate the vibration signal model of the gear system under fault-free conditions, employing a periodic rectangular window function. Amplitude modulation of the fault-free vibration signal yields a phenomenological model of the vibration signal under a broken tooth fault condition in the gear pair:

[0057] (1);

[0058] (2);

[0059] (3);

[0060] In the formula, This is the expression for the vibration signal model under fault conditions. It is the meshing harmonic number. Basic meshing frequency ,in, It's the number of teeth. It is the rotational frequency of the faulty gear. and It refers to the amplitude and initial phase; For the periodic rectangular window fault amplitude modulation function, This represents a pulse sequence caused by a local fault. The pulse amplitude; The rotational cycle of the faulty gear is given, and the start / end time of each fault is given. ; It is a periodic rectangular window function with an amplitude of 1.

[0061] In a double-row planetary gear system, using Represents the sun chakra. The first row of planetary gears that meshes directly with the sun gear is represented by... This indicates the sequence of planetary gears that mesh with the sun gear; This indicates the second row of planetary gears that meshes with the gear ring; This represents the ring gear. Therefore, the meshing pairs of the sun gear-first row of planetary gears, the first row of planetary gears-second row of planetary gears, and the second row of planetary gears-ring gear can be represented as follows: , and ; , and The vibration generated when the gear pair meshes at the engagement point. , and It can be represented as Vibration generated by gear meshing The time-shift results were obtained, and their relative phases were considered. It was assumed that similar gear pairs had the same amplitude. , and It can be written as:

[0062] (4);

[0063] (5);

[0064] (6);

[0065] in, It is the meshing harmonic number, where For the first q The amplitude of the meshing vibration; The meshing frequency of the planetary gear train. For the meshing cycle of the planetary gear train, , As the initial phase of the reference meshing pair vibration, For gear pairs and The phase difference; For gear pairs and The phase difference; For gear pairs and The phase difference; for ; for and The phase difference.

[0066] Table 1 shows the analog data used for the analog signal, where it is assumed that different gear pairs have the same amplitude because the structure is a floating gear ring.

[0067] Table 1: Simulation Data

[0068]

[0069] Time-domain images in a healthy state, such as Figure 2 As shown, the frequency domain image under healthy conditions is as follows: Figure 3 As shown.

[0070] When the sun gear experiences a partial failure The vibration of the gear pair will be modulated by periodic pulses caused by the fault. and The vibration of the gear pair remains constant. The sun gear is fixed, therefore, 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 .

[0071] When a broken tooth occurs on the sun gear, assuming the faulty tooth is the initial meshing tooth (the first tooth), it only affects the teeth in direct contact with it. For the gear pair, referring to the vibration signal model of the faulty gear pair established by formula (1), the phenomenological model of the broken tooth of the sun gear is obtained:

[0072] (7);

[0073] (8);

[0074] In the formula, For the sun wheel - the first Expression of vibration signal of a planetary gear meshing pair The expression represents the vibration signal of all sun gear-planet gear meshing pairs (in the simulation process of this invention, there are 3 planet gears in each double row). The rotational frequency of the sun gear relative to the planetary carrier. ; For the periodic rectangular window function when the sun gear fails, the specific expression is shown in formula (2). At this time, the rotational frequency of the faulty gear in formula (2) is... for A simulation experiment was conducted according to formula (8), and the amplitude of the fault caused by the sun gear tooth was set as... That is, as shown in formula (2) The results are as follows Figure 4 and Figure 5 As shown.

[0075] like Figure 4 As shown, the broken teeth of the sun gear mesh sequentially with three planet gears (this implementation uses three as an example), with an interval between them. There are three sets of planetary gears. As the sun completes one revolution, the faulty gear engages three times. This is reflected in the time-domain image at intervals of... One impact occurs over a period of time, and three impacts occur during one revolution of the sun; for example... Figure 5 As shown, in the frequency domain image, the meshing frequency As the fundamental frequency, it will generate meshing frequency harmonic components in the frequency spectrum. At meshing frequency The planetary carriers on both sides have a rotational frequency multiplication factor. Modulation sideband This fault characteristic can be used to detect localized faults in the sun gear teeth.

[0076] When a planetary gear meshing with the sun gear experiences a broken tooth failure, only one planetary gear suffers the failure, while the other planetary gears function normally. Assume the first planetary gear... Planetary gears ( A malfunction occurs, and the faulty tooth is the initial meshing tooth, i.e., the first tooth, affecting the sun gear that is in direct contact with it and the meshing pair with the second row of planetary gears. Initially... At this moment, the faulty gear just engages with the sun gear. The time interval required from the start of engagement with the sun gear to engagement with the other planet gear is... Based on 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:

[0077] (9);

[0078] (10);

[0079] (11);

[0080] In the formula, For the first The expression for the vibration signal of the sun gear-planet gear pair meshing with the sun gear. Indicates the first Expression for the vibration signal of a planetary gear-planetary gear meshing pair Indicates all gears with faults The expression for the vibration signal generated by a meshing gear pair. This represents the rotational frequency of the first row of planetary gears relative to the planet carrier. and The periodic rectangular window function is used when the first row of planetary gears fails. The specific expression is given in formula (2). At this time, the rotational frequency of the faulty gear in formula (2) is... for A simulation experiment was conducted according to formula (11), assuming... The fault amplitude of the gear pair is 10. The fault amplitude of the gear pair is 5, which is shown in formula (2). 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 0.0213 s; simultaneously, the frequency-domain image describes the modulation sidebands 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 broken tooth faults in planetary gears meshing with the sun gear in a double-row planetary gear train.

[0081] When a planetary gear meshing with the ring gear experiences a broken tooth failure, only one planetary gear will have a broken tooth, while the other planetary gears will continue to function normally. Assume the... Planetary gears ( A fault occurs, assuming the faulty tooth is the initial meshing tooth, i.e., the first tooth, affecting the gear ring that directly contacts it and the meshing pair with the first set of planetary gears. At the initial moment... At this moment, the faulty tooth just engages with the first set of planetary gears. The time interval required from the start of engagement with the first set of planetary gears to engagement with the gear ring is... Based on 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 gear ring is obtained:

[0082] (12);

[0083] (13);

[0084] (14);

[0085] In the formula, For the first Expression for the vibration signal of a planetary gear-planetary gear meshing pair Indicates the first Expressions for the vibration signals of planetary gear-ring gear meshing pairs. Indicates all teeth with faults The expression for the vibration signal generated by a meshing gear pair. This refers to the rotational frequency of the second row of planetary gears relative to the planet carrier. and The periodic rectangular window function is used when the second row of planetary gears fails. The specific expression is given in formula (2). At this time, the rotational frequency of the faulty gear in formula (2) is... for A simulation experiment was conducted according to formula (14), assuming... The fault amplitude of the gear pair is 10. The fault amplitude of the gear pair is 5, which is shown in formula (2). The results are as follows Figure 8 and Figure 9 As shown.

[0086] like Figure 8 As shown, in the time-domain image, the sensor periodically receives two periodic pulse sequences with a time interval of 0.0340 s; simultaneously, the frequency-domain image describes the modulation sidebands 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 broken tooth faults in planetary gears meshing with the gear ring in a double-row planetary gear train.

[0087] To verify the validity of the established vibration model and theoretical derivation, four sets of experiments were conducted on an experimental platform. The experimental platform consisted 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 was composed of a sun gear. Planetary gears and gear ring The components are configured with 30, 21, and 72 teeth respectively. The second stage of the two-stage planetary gearbox includes a sun gear. Planetary gears Planetary gears and gear ring The number of teeth are respectively , and .

[0088] The signal acquired under healthy conditions is the fundamental frequency signal. Then, the following fault scenarios are investigated: Scenario 1: Broken sun gear tooth; Scenario 2: First row of planetary gears. Broken tooth; Case 3: Second row of planetary gears Broken tooth.

[0089] During the experiment, the input shaft connected to the sun gear was set to 700 rpm, and the load on the output shaft connected to the planetary carrier was 200 Nm. Vibration signals were measured by a triaxial accelerometer mounted on the gearbox housing, with a sampling frequency of 5120 Hz and a duration of 10 min.

[0090] Based on the transmission mechanism of the two-stage planetary gearbox, the velocity characteristic equation of the two-stage gear train is:

[0091] (15);

[0092] (16);

[0093] According to formulas (15) and (16), substitute... actual rotation frequency , actual rotation frequency and = (The number of teeth on the gear rings in the two-stage gear trains are different, but the rotational speed is the same. The gear rings are a single structure, and only the number of teeth on the gear rings of different stages differs.) The absolute rotational frequency, relative rotational frequency and meshing frequency of each stage of the experimental gearbox were calculated and are shown in Table 2.

[0094] Table 2: Rotation speed and meshing frequency of various components in the gearbox

[0095]

[0096] The vibration signal of the gearbox under healthy conditions was analyzed and used as a reference signal for comparison with the experimental signal of subsequent tooth breakage failure. The reference signal was measured when all gears were in healthy condition. Figure 10 and Figure 11 The time-domain and frequency-domain response plots of the reference signal are displayed.

[0097] pass Figure 10 and Figure 11 It can be seen that the spectral lines with larger amplitudes in the actual spectrum are mainly located at the meshing frequency and its harmonics. The actual meshing frequency is basically consistent with the theoretical meshing frequency, and the second-stage meshing frequency is approximately 182Hz, and its harmonics are... These phenomena coexist and are basically consistent with the simulation results, thus verifying the accuracy and correctness of the model. Due to unavoidable manufacturing and installation errors and noise interference, some irregular sidebands with low amplitude appear in the spectrum. Furthermore, due to the complex structure of the gearbox, in addition to the object of this study, it also includes rotating components such as shafts, bearings, and other gear transmission systems; therefore, the test spectrum also contains other spectral lines with larger amplitudes.

[0098] (1) The case of a broken tooth in the sun gear.

[0099] Figure 12 , Figure 13 and Figure 14 The time-domain image, frequency-domain image, and magnified view of the frequency-domain image of the vibration signal of the two-stage planetary gearbox when the sun gear breaks are shown. Specifically, Figure 13 The time-domain plot of the vibration signal is the same as the model prediction, and the following observations were made. The periodic recurring impact. Figure 14 The frequency domain diagram of the vibration signal shows that the sidebands of the vibration signal under fault conditions are much richer than those of the baseline signal. Figure 15 This is a frequency domain magnified waveform of the vibration signal. The figure shows... The modulation sideband corresponds to the meshing harmonics in the simulation experiment. There are modulation sidebands on both sides with relative rotation frequencies of the sun gear. The vibration law derived from this phenomenon is consistent with the theoretical derivation, thus verifying the accuracy of the model.

[0100] This invention analyzes experimental images of broken teeth on planetary gears meshing with the sun gear and planetary gears meshing with the ring gear in a double-row planetary gear system. The time-domain impact time interval and frequency-domain vibration frequency obtained from the images are compared with the simulation experimental results to verify the reliability of the model.

[0101] (2) Planetary gears meshing with the sun gear The situation of a broken tooth.

[0102] Figure 15 , Figure 16 and Figure 17 The images represent the time-domain image, frequency-domain image, and frequency-domain magnified waveform image of the vibration signal when a tooth breaks in the planetary gear (first row of planetary gears) meshing with the sun gear. Figure 16 The figure shows the time-domain waveform of the field test signal under the condition of broken tooth failure of the planetary gear. The period can be seen from the figure as approximately The two periodic pulse sequences correspond to the time it takes for the second-stage planetary gear to rotate one revolution relative to the planet carrier, meaning the frequencies of the two periodic pulses are... The cycle is Two adjacent impacts appear periodically in the time-domain signal, with a time interval of approximately This 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. . Figure 17 The spectrum of the vibration signal when a planetary gear meshing with the sun gear breaks is shown. Figure 18 The image shows an amplified waveform of the vibration signal when a planetary gear meshing with the sun gear breaks. The waveform shows... The modulation sideband corresponds to the meshing harmonics in the simulation experiment. There are modulation sidebands on both sides with intervals between the first row of planetary gears and their relative rotational frequency. .

[0103] (3) Planetary gears meshing with the gear ring The situation of a broken tooth.

[0104] Figure 18 , Figure 19 and Figure 20These are the time-domain, frequency-domain, and frequency-domain magnified waveforms of the vibration signal when a tooth breaks on the planetary gear (i.e., the second row of planetary gears) meshing with the gear ring. Figure 19 The figure shows the time-domain waveform of the field test signal under the condition of a broken tooth in the planetary gear meshing with the sun gear in the second stage. The period can be seen from the figure as approximately The two periodic pulse sequences correspond to the time it takes for the second row of planetary gears to rotate one revolution relative to the planet carrier, meaning the frequencies of the two periodic pulses are... The cycle is Two adjacent impacts appear periodically in the time-domain signal, with a time interval of approximately This corresponds to the time interval between the broken tooth position of the planetary gear and the sequential meshing of the first set of planetary gears and the ring gear. . Figure 20 The spectrum of the vibration signal when a planetary gear meshing with a gear ring breaks is shown. Figure 21 The image shows an amplified waveform of the vibration signal when a planetary gear meshing with a gear ring breaks. The waveform shows... The modulation sideband corresponds to the meshing harmonics in the simulation experiment. There are modulation sidebands on both sides with intervals between the first row of planetary gears and their relative rotational frequency. .

[0105] Due to the second-stage planetary wheel and planetary wheel Since the rotation time and fault characteristic frequency are the same as the theoretically calculated values ​​of the planetary carrier, it is impossible to accurately determine from the envelope spectrum or Fourier spectrum that the damaged tooth occurred on the planetary gear. Or planetary wheel However, the time interval characteristics of adjacent impact components extracted from the time-domain signal, i.e., the time intervals between faulty teeth located on different gears, are different ( and It can be determined that the damaged teeth are located on the planetary gears. Up or The vibration law derived from this phenomenon is consistent with the theoretical derivation, thus verifying the accuracy of the model.

[0106] In summary, this invention proposes vibration patterns for different types of faults:

[0107] Vibration patterns of sun gear failure: Vibration frequency domain image at meshing frequency There are nearby intervals equal to the number of planetary gears. Harmonics ( (Number of planetary gears), fault characteristic frequency There are time intervals in the time domain image. The impact;

[0108] Vibration characteristics when the planetary gears meshing with the sun gear (i.e., the first row of planetary gears) fail: Vibration frequency domain image at the meshing frequency The relative rotational frequency of the planetary gears relative to the planet carrier exists nearby at intervals of . Modulation harmonics, i.e., fault characteristic frequencies The time-domain image contains time intervals of The impact occurs because the faulty tooth meshes with the sun gear and the second set of planetary gears respectively, and their fault modulation frequencies are the same, both being... In the time-domain image, the time interval between the two sets of impacts is:

[0109] (17);

[0110] in,

[0111] (18);

[0112] (19);

[0113] The base round teeth of the planetary gear are thick. for Gear pair and The included angle between the lines connecting the centers of the gear pair. For pressure angle, These are the base circle radius and addendum circle radius of the first row of planetary gears, respectively. A gear pair represents the sun gear and the first planetary gear in the first row. A gear pair consisting of planetary gears The gear pair represents the first planetary gear in the first row. The first planetary gear and the first planetary gear in the second row A gear pair consisting of planetary gears , and These respectively represent the center of the sun wheel and the first planetary wheel in the first row. The center of the first planetary gear and the first planetary gear in the second row. The center of each planetary gear.

[0114] Vibration characteristics when the planetary gears meshing with the ring gear (i.e., the second set of planetary gears) fail: Vibration frequency domain image at the meshing frequency The relative rotational frequency of the planetary gears relative to the planet carrier exists nearby at intervals of . Modulation harmonics, i.e., fault characteristic frequencies The time-domain image contains time intervals of The impact, due to the faulty tooth meshing with the gear ring and the first set of planetary gears respectively, has the same fault modulation frequency. In the time-domain image, the time interval between the two sets of impacts is:

[0115] (20);

[0116] in,

[0117] (twenty one);

[0118] (twenty two);

[0119] The base round teeth of the planetary gear are thick. for Gear pair and The angle between the lines connecting the centers of the circles. For pressure angle, These are the base circle radius and the addendum circle radius of the planetary gear, respectively. These are the base circle radius and the addendum circle radius of the gear ring, respectively. The gear pair represents the gear ring and the first gear in the second row of planetary gears. A gear pair consisting of planetary gears The gear pair represents the first planetary gear in the first row. The first planetary gear and the first planetary gear in the second row A gear pair consisting of planetary gears , and These respectively represent the center of the gear ring and the first planetary gear in the first row. The center of the first planetary gear and the first planetary gear in the second row. The center of each planetary gear, the center of the ring gear, and the center of the sun gear are all... .

[0120] Figure 21 A partial fault diagnosis system for double-row planetary gears has been developed, comprising:

[0121] 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 phenomenological model of sun gear tooth breakage to obtain a first time domain image and a first frequency domain image; when a first modulation harmonic appears within a set frequency range before and after the meshing frequency in the first frequency domain image, and there is an impact with a first set period interval in the first time domain image, it is determined that there is a sun gear tooth breakage fault.

[0122] The first planetary gear tooth breakage identification unit 2102 is configured to: perform fault simulation based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken planetary gear meshing with the sun gear to obtain a second time domain image and a second frequency domain image; when a second modulation harmonic appears within a set frequency range before and after the meshing frequency in the second frequency domain image, and there is an impact with a second set period interval in the second time domain image, the planetary gear meshing with the sun gear is determined to be faulty.

[0123] The second planetary gear tooth breakage identification unit 2103 is configured to: time domain image and third frequency domain image. When a third modulation harmonic appears within a set frequency range before and after the meshing frequency in the third frequency domain image, and there is an impact with a third set period interval in the third time domain image, the planetary gear meshing with the gear ring is determined to be faulty.

[0124] It is understood that the aforementioned units can be individually or entirely merged into one or more other units, or some of the units can be further divided into multiple functionally smaller units. This achieves the same operation without affecting the technical effects of the embodiments of this application. The aforementioned units are based on logical functional division. In practical applications, the function of one unit can be implemented by multiple units, or the function of multiple units can be implemented by one unit. In other embodiments of this application, the system may also include other units. In practical applications, these functions can also be implemented with the assistance of other units, and can be implemented collaboratively by multiple units.

[0125] According to another embodiment of this application, the system described in this embodiment can be constructed by running a computer program (including program code) capable of performing 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, loaded into the aforementioned computing device through the computer-readable recording medium, and run therein.

[0126] 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, communication interface 2202, and computer-readable storage medium 2203 can be connected via a bus or other means.

[0127] 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, which include program instructions. The processor 2201 is used to execute the program instructions stored in the computer-readable storage medium 2203.

[0128] The processor 2201 is the computing and control core of the electronic device. It is suitable for implementing one or more instructions, specifically for loading and executing one or more instructions to achieve the corresponding method flow or corresponding function.

[0129] The processor 2201 is configured to perform the following procedure:

[0130] Based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken sun gear tooth, a fault simulation is performed to obtain a first time domain image and a first frequency domain image. When a first modulation 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, it is determined that there is a broken sun gear tooth fault.

[0131] Based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken teeth of the planetary gears meshing with the sun gear, a fault simulation is performed to obtain a second time-domain image and a second frequency-domain image. When a second modulation harmonic appears within a set frequency range before and after the meshing frequency in the second frequency-domain image, and there is an impact with a second set period interval in the second time-domain image, the fault of the planetary gear meshing with the sun gear is determined.

[0132] Based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken teeth of the planetary gears meshing with the gear ring, a fault simulation is performed to obtain a third time-domain image and a third frequency-domain image. When a third modulation 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, the fault of the planetary gear meshing with the gear ring is determined.

[0133] This 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 here may include both built-in storage media in the electronic device and extended storage media supported by the electronic device. The computer-readable storage medium provides storage space for storing the processing system of the electronic device.

[0134] Furthermore, this storage space also contains one or more instructions suitable for loading and execution by the processor. These instructions can be one or more computer programs (including program code). It should be noted that the computer-readable storage medium here can be high-speed RAM memory or unstable memory, such as at least one disk storage device; optionally, it can also be at least one computer-readable storage medium located remotely from the aforementioned processor.

[0135] 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 perform the following process:

[0136] Based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken sun gear tooth, a fault simulation is performed to obtain a first time domain image and a first frequency domain image. When a first modulation 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, it is determined that there is a broken sun gear tooth fault.

[0137] Based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken teeth of the planetary gears meshing with the sun gear, a fault simulation is performed to obtain a second time-domain image and a second frequency-domain image. When a second modulation harmonic appears within a set frequency range before and after the meshing frequency in the second frequency-domain image, and there is an impact with a second set period interval in the second time-domain image, the fault of the planetary gear meshing with the sun gear is determined.

[0138] Based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken teeth of the planetary gears meshing with the gear ring, a fault simulation is performed to obtain a third time-domain image and a third frequency-domain image. When a third modulation 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, the fault of the planetary gear meshing with the gear ring is determined.

[0139] The present invention also provides a computer program product or computer program comprising 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:

[0140] Based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken sun gear tooth, a fault simulation is performed to obtain a first time domain image and a first frequency domain image. When a first modulation 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, it is determined that there is a broken sun gear tooth fault.

[0141] Based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken teeth of the planetary gears meshing with the sun gear, a fault simulation is performed to obtain a second time-domain image and a second frequency-domain image. When a second modulation harmonic appears within a set frequency range before and after the meshing frequency in the second frequency-domain image, and there is an impact with a second set period interval in the second time-domain image, the fault of the planetary gear meshing with the sun gear is determined.

[0142] Based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken teeth of the planetary gears meshing with the gear ring, a fault simulation is performed to obtain a third time-domain image and a third frequency-domain image. When a third modulation 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, the fault of the planetary gear meshing with the gear ring is determined.

[0143] Those skilled in the art will recognize that the units and algorithm steps of the various examples 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 implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can 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.

[0144] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. 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 or transmitted through 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, fiber optic cable, digital cable) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that a computer can access or a data processing device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state drive), etc.

[0145] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for diagnosing local faults in a double-row planetary gear system, characterized in that, Includes the following processes: Based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken sun gear tooth, a fault simulation is performed to obtain a first time domain image and a first frequency domain image. When a first modulation 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, it is determined that there is a broken sun gear tooth fault. Based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken teeth of the first row of planetary gears meshing with the sun gear, a fault simulation is performed to obtain a second time-domain image and a second frequency-domain image. When a second modulation harmonic appears within a set frequency range before and after the meshing frequency in the second frequency-domain image, and there is an impact with a second set period interval in the second time-domain image, the first row of planetary gears meshing with the sun gear is determined to be faulty. Based on the operating parameters of the double-row planetary gears and the phenomenological model of the broken teeth of the second row of planetary gears meshing with the gear ring, a fault simulation is performed to obtain a third time-domain image and a third frequency-domain image. When a third modulation harmonic appears within a set frequency range before and after the meshing frequency in the third frequency-domain image, and there is an impact with a third set period interval in the third time-domain image, the second row of planetary gears meshing with the gear ring is determined to be faulty. When the second modulation harmonic appears within a set frequency range before and after the meshing frequency in the second frequency domain image, it indicates a fault harmonic. for: , Represents the meshing frequency. The relative rotational frequency of the first row of planetary gears meshing with the sun gear relative to the planet carrier, and the second set period interval are: ; When a third modulation harmonic appears within a set frequency range before and after the meshing frequency in the third frequency domain image, it indicates a fault harmonic. for: , Represents the meshing frequency. The relative rotational frequency of the first row of planetary gears meshing with the sun gear relative to the planet carrier, and the third set period interval are: ; In a double-row planetary gear system, using Represents the sun chakra. The first row of planetary gears that meshes directly with the sun gear is represented by... This indicates the sequence of the first row of planetary gears that meshes with the sun gear; This indicates the second row of planetary gears that meshes with the gear ring; This refers to a ring gear, which is a floating ring gear. The meshing pairs are: sun gear - first row of planetary gears, first row of planetary gears - second row of planetary gears, and second row of planetary gears - ring gear. , and ; When a broken tooth occurs in the first set of planetary gears meshing with the sun gear, only one planetary gear experiences a broken tooth failure, while the other planetary gears function normally. Assuming the first... Planetary wheel A malfunction occurs, and the faulty tooth is the initial meshing tooth, i.e., the first tooth. This affects the sun gear, which is in direct contact with it, and the meshing pair with the second row of planetary gears. Initially... At this point, the faulty tooth engages with the sun gear, resulting in a phenomenological model of the broken tooth on the first row of planetary gears meshing with the sun gear: ； ； ； In the formula, For the first The expression for the vibration signal of the sun gear-planet gear pair meshing with the sun gear. Indicates the first Expression for the vibration signal of a planetary gear-planetary gear meshing pair Indicates all gears with faults The expression for the vibration signal generated by a meshing gear pair. and This is a periodic rectangular window function for the first row of planetary gears in case of failure. Represents the meshing harmonic number, All are the corresponding first q The amplitude of the meshing vibration. As the initial phase of the reference meshing pair vibration, For gear pairs and phase difference, The time interval between the broken tooth position of the first row of planetary gears meshing with the sun gear and the sequential meshing of the paired sun gear and the second row of planetary gears; When a broken tooth occurs in the second set of planetary gears meshing with the ring gear, only one planetary gear experiences a broken tooth, while the other planetary gears function normally; assuming the... Planetary wheel A failure occurs, assuming the faulty tooth is the initial meshing tooth, i.e., the first tooth, affecting the gear ring that directly contacts it and the meshing pair with the first set of planetary gears. Initially... At this point, the faulty tooth engages with the first set of planetary gears, resulting in a phenomenological model of the broken tooth in the second set of planetary gears meshing with the gear ring: ； ； ； In the formula, For the first Expression for the vibration signal of a planetary gear-planetary gear meshing pair Indicates the first Expressions for the vibration signals of planetary gear-ring gear meshing pairs. Indicates all teeth with faults The expression for the vibration signal generated by a meshing gear pair. and For a periodic rectangular window function when the second row of planetary gears fails, For gear pairs and phase difference, For the meshing cycle of the planetary gear train, Represents a gear pair With gear pair phase difference, The time interval required for the second set of planetary gears, which meshes with the ring gear, to begin meshing with the first set of planetary gears and then engage with the ring gear.

2. The method for diagnosing local faults in double-row planetary gears as described in claim 1, characterized in that, When the first modulation harmonic appears within a 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. This represents the number of the first row of planetary gears that mesh with the sun gear; The first set period interval is: .

3. The method for diagnosing local faults in double-row planetary gears as described in claim 1, characterized in that, Phenomenological Model of Broken Teeth of Sun Gear for: ,in, Represents the sun wheel - the first Expression of vibration signal of a planetary gear meshing pair This represents the number of the first row of planetary gears that mesh with the sun gear. The calculations were performed based on the operating parameters and fault modulation mechanism of the double-row planetary gears.

4. The method for diagnosing local faults in double-row planetary gears as described in claim 1, characterized in that, Phenomenological model of the broken teeth of the first row of planetary gears meshing with the sun gear for: ,in, Representing the The expression for the vibration signal of the sun gear-planet gear pair meshing with the sun gear. This represents the number of the first row of planetary gears that mesh with the sun gear. Representing the Expression for the vibration signal of a planetary gear-planetary gear meshing pair and The calculations were performed based on the operating parameters and fault modulation mechanism of the double-row planetary gears.

5. The method for diagnosing local faults in double-row planetary gears as described in claim 1, characterized in that, Phenomenological model of broken teeth of the second row of planetary gears meshing with the gear ring for: ,in, This represents the number of the first row of planetary gears that mesh with the sun gear. Representing the Expression for the vibration signal of a planetary gear-planetary gear meshing pair Indicates the first Expressions for the vibration signals of planetary gear-ring gear meshing pairs. and The calculations were performed based on the operating parameters and fault modulation mechanism of the double-row planetary gears.

6. A partial fault diagnosis system for double-row planetary gears, characterized in that, The method for diagnosing partial faults in a double-row planetary gear as described in any one of claims 1-5 includes: 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 phenomenological model of sun gear tooth breakage to obtain a first time domain image and a first frequency domain image; when a first modulation harmonic appears within a set frequency range before and after the meshing frequency in the first frequency domain image, and there is an impact with a first set period interval in the first time domain image, it is determined that there is a sun gear tooth breakage fault. The first planetary gear tooth breakage 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 first row of planetary gears meshing with the sun gear, and obtain a second time-domain image and a second frequency-domain image. When a second modulation harmonic appears within a set frequency range before and after the meshing frequency in the second frequency-domain image, and there is an impact with a second set period interval in the second time-domain image, the first row of planetary gears meshing with the sun gear is determined to be faulty. The second planetary gear tooth breakage 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 second row of planetary gears meshing with the gear ring, and obtain a third time-domain image and a third frequency-domain image. When a third modulation 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, the second row of planetary gears meshing with the gear ring is determined to be faulty.

7. A computer device, characterized in that, include: Processor and computer-readable storage media; A processor, adapted to execute computer programs; A computer-readable storage medium storing a computer program, which, when executed by the processor, implements the partial fault diagnosis method for a double-row planetary gear as described in any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program adapted to be loaded by a processor and executed as described in any one of claims 1 to 5 for the local fault diagnosis method of a double-row planetary gear.

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