Damage state diagnosis system and damage state diagnosis method

Abstract

A sensor (20) detects vibration generated when a rolling bearing (10) rotates. A diagnosis device (100) includes a preprocessing section (30), a feature quantity extraction section (50), and a damage state diagnosis section (60). The preprocessing section (30) generates a vibration waveform by acquiring an output signal of the sensor (20) over a period in which a rotation ring (12) rotates a plurality of revolutions. The feature quantity extraction section (50) extracts a plurality of feature quantities from the vibration waveform. The damage state diagnosis section (60) diagnoses a damage state of the rolling bearing (10) based on the plurality of feature quantities extracted by the feature quantity extraction section. The plurality of feature quantities include a peeling length or a non-peeling length in a circumferential direction of the rolling bearing (10), a peeling passage number of each rolling body (13) passing through peeling over a period in which the rotation ring (12) rotates one revolution, and a dispersion index indicating dispersion of an amplitude of the vibration waveform.

Description

Technical Field

[0001] This disclosure relates to a damage condition diagnosis system and method for diagnosing the damage condition of rolling bearings. Background Technology

[0002] Vibration characteristics can be used to diagnose the damage state of rolling bearings used in mechanical equipment, indicating the degree of damage progression. For example, Japanese Patent Application Publication No. 2017-32520 (Patent Document 1) discloses a technique that generates waveforms in three frequency bands based on vibration data of a rolling bearing, and diagnoses the damage state of the rolling bearing based on the effective vibration value of each frequency band. In the early stage of damage, only the effective value of the high-frequency band responds, and as the damage progresses, the effective value of the low-frequency band increases. In Patent Document 1, the damage state of the rolling bearing is evaluated in three stages by monitoring the effective vibration values ​​of the above three frequency bands.

[0003] In addition, Japanese Patent No. 6733838 (Patent Document 2) discloses the following technology: for damage caused by ring peeling, the peeling length in the circumferential direction of the rolling bearing is estimated based on the time difference between the entry time of the rolling element into the ring peeling area and the exit time of the rolling element from the ring peeling area.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-32520

[0007] Patent Document 2: Japanese Patent No. 6733838 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] The technology described in Patent Document 1 divides the damage state of rolling bearings into three stages for evaluation, which results in the inability to quantitatively evaluate the damage state.

[0010] On the other hand, the technology described in Patent Document 2 allows for a quantitative evaluation of the damage condition based on the peeling length in the circumferential direction of the rolling bearing. However, Patent Document 2 can only evaluate the peeling progress occurring at one location of the rolling bearing, and cannot evaluate peeling occurring at multiple locations of the rolling bearing. Furthermore, Patent Document 2 cannot determine which location on the rotating ring, stationary ring, and rolling elements constituting the rolling bearing experienced peeling.

[0011] This disclosure was made to solve the above-mentioned problems, and the purpose of this disclosure is to provide a technique capable of diagnosing damage conditions with high precision, the damage condition representing the degree of damage progression of a rolling bearing from the occurrence of one peel to the occurrence of multiple peels.

[0012] Solution for solving the problem

[0013] A damage condition diagnosis system according to one aspect of this disclosure diagnoses the damage condition of a rolling bearing, indicating the degree of damage progression. The rolling bearing includes a fixed ring, a rotating ring, and a plurality of rolling elements arranged circumferentially between the fixed ring and the rotating ring at equal pitch intervals. The damage condition diagnosis system includes: a sensor for detecting vibrations generated when the rolling bearing rotates; and a diagnostic device for diagnosing the damage condition of the rolling bearing based on the output signal of the sensor. The diagnostic device includes a preprocessing unit, a feature extraction unit, and a damage condition diagnosis unit. The preprocessing unit generates a vibration waveform by acquiring the sensor's output signal within a time span of multiple rotations of the rotating ring. The feature extraction unit extracts a plurality of feature quantities from the vibration waveform. The damage condition diagnosis unit diagnoses the damage condition of the rolling bearing based on the plurality of feature quantities extracted by the feature extraction unit. The plurality of feature quantities include the peel length or non-peel length in the circumferential direction of the rolling bearing, the number of peel passes of each rolling element within one rotation of the rotating ring, and a dispersion index representing the amplitude dispersion of the vibration waveform.

[0014] The effects of the invention

[0015] According to this disclosure, the damage condition can be diagnosed with high precision, which indicates the degree of damage progression of a rolling bearing from the occurrence of one peel to the occurrence of multiple peels. Attached Figure Description

[0016] Figure 1 This is a block diagram illustrating the overall structure of the damage condition diagnosis system according to an embodiment of this disclosure.

[0017] Figure 2 This is a diagram illustrating an example of the hardware structure of a diagnostic device.

[0018] Figure 3 This is a diagram showing an example of a displacement vibration waveform.

[0019] Figure 4 This is a diagram showing an example of the displacement vibration waveform during the time it takes for the rotating ring to complete one revolution.

[0020] Figure 5 This is a diagram showing an example of the displacement vibration waveform during the time it takes for the rotating ring to complete one revolution.

[0021] Figure 6 This is a schematic diagram illustrating the load ring of a rolling bearing.

[0022] Figure 7 This is a schematic diagram used to illustrate pitch interval stripping.

[0023] Figure 8 This is a diagram showing an example of the displacement vibration waveform over the time it takes for the rotating ring to rotate 4 times.

[0024] Figure 9 This is a diagram showing an example of the displacement vibration waveform over the time it takes for the rotating ring to rotate 4 times.

[0025] Figure 10 This is a diagram illustrating an example of a displacement vibration waveform equivalent to two rotations when the fixed ring produces pitch gap peeling.

[0026] Figure 11 This is a diagram illustrating an example of a displacement vibration waveform equivalent to two rotations when a rotating ring produces pitch gap peeling.

[0027] Figure 12 This is a flowchart illustrating the damage diagnosis and processing procedures in the damage diagnosis department.

[0028] Figure 13 This is a diagram showing the structure and operating conditions of the rolling bearing used in the embodiment.

[0029] Figure 14 This is a diagram illustrating the peeling conditions in the embodiments.

[0030] Figure 15 This is a graph showing the number of peeling passes extracted from the displacement vibration waveform under various conditions.

[0031] Figure 16 This is a graph showing the discrete index extracted from the displacement vibration waveform under various conditions.

[0032] Figure 17 This is a graph showing the peeling length extracted from the displacement vibration waveform under various conditions.

[0033] Figure 18 This is a graph showing the change in the ratio of static displacement relative to the number of peels.

[0034] Figure 19 This is a graph showing the results of calculating the dispersion index when n=4.

[0035] Figure 20 This is a diagram showing an example of the displacement vibration waveform over the time it takes for the rotating ring to rotate 4 times.

[0036] Figure 21 This is a diagram showing an example of the displacement vibration waveform over the time it takes for the rotating ring to rotate 4 times.

[0037] Figure 22 This is a graph showing the corrected dispersion index.

[0038] Figure 23 This is a block diagram illustrating a modified example of the damage condition diagnosis system according to this embodiment.

[0039] Figure 24 This is a diagram showing an example of a displacement vibration waveform.

[0040] Figure 25 This is a flowchart illustrating the damage state diagnosis process in the damage state diagnosis unit involved in the modified example.

[0041] Figure 26 This is a diagram illustrating the peeling conditions in Example 2.

[0042] Figure 27 This is a graph showing the number of peeling passes extracted from the displacement vibration waveform under various conditions.

[0043] Figure 28 This is a graph showing the discrete index extracted from the displacement vibration waveform under various conditions.

[0044] Figure 29 This is a graph showing the non-stripping length extracted from the displacement vibration waveform under various conditions. Detailed Implementation

[0045] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Furthermore, the same or equivalent parts in the drawings are labeled with the same reference numerals, and their descriptions will not be repeated.

[0046] <Structure of Damage Condition Diagnostic System>

[0047] Figure 1 This is a block diagram illustrating the overall structure of the damage condition diagnosis system according to an embodiment of this disclosure. Figure 1 As shown, the damage state diagnosis system involved in this embodiment is a system for diagnosing the damage state that indicates the degree of damage progression of the rolling bearing 10.

[0048] The rolling bearing 10 includes a fixed ring 11, a rotating ring 12, and a plurality of rolling elements 13 rotatably disposed between the fixed ring 11 and the rotating ring 12. The rolling bearing 10 also includes a cage 14 that freely holds the plurality of rolling elements 13. The plurality of rolling elements 13 are arranged at equal pitch intervals in the circumferential direction of the rolling bearing 10 by means of the cage 14.

[0049] The rotating ring 12 is externally embedded in the rotating shaft of the mechanical equipment. The fixed ring 11 is internally embedded in the housing or other components. In addition, in this embodiment, the case of a rolling bearing consisting of a roller bearing with an inner ring as the rotating ring is described as an example, but the scope of this disclosure is not limited to damage estimation devices for such bearings. The rolling bearing may be a structure with an outer ring as the rotating ring, or it may be a ball bearing or the like.

[0050] The damage condition diagnosis system includes a sensor 20 and a diagnostic device 100. The sensor 20 is configured to detect the acceleration, velocity, or displacement of the vibration generated when the rolling bearing 10 rotates. The sensor 20 may be an acceleration sensor, a velocity sensor, or a displacement sensor. The sensor 20 outputs a signal representing the detected value to the diagnostic device 100.

[0051] The diagnostic device 100 diagnoses the damage condition of the rolling bearing 10 based on the output signal of the sensor 20. Figure 2 This is a diagram illustrating an example of the hardware structure of the diagnostic device 100. (As shown...) Figure 2 As shown, the diagnostic device 100 includes a CPU (Central Processing Unit) 101, RAM (Random Access Memory) 102, ROM (Read-Only Memory) 103, I / F (Interface) device 104, and storage device 105. The CPU 101, RAM 102, ROM 103, I / F device 104, and storage device 105 exchange and send various types of data through a communication bus 106.

[0052] CPU 101 loads the program stored in ROM 103 into RAM 102 for execution. The program stored in ROM 103 describes the processing performed by diagnostic device 100.

[0053] The I / F device 104 is an input / output device for exchanging signals and data with external devices (such as the sensor 20, a monitoring terminal, etc.) of the diagnostic device 100. The I / F device 104 receives the output signal from the sensor 20. In addition, the I / F device 104 sends damage status data indicating the diagnostic results to the monitoring terminal.

[0054] Storage device 105 is a memory that stores various types of information, such as information about the rolling bearing 10 being diagnosed, information about the vibration waveform generated based on the output signal of sensor 20, and information about the feature quantities extracted from the vibration waveform. Storage device 105 may be, for example, an HDD (Hard Disk Drive) or an SSD (Solid State Drive).

[0055] In addition, with Figure 2 Unlike other examples, at least a portion of the diagnostic device 100 may be constructed using circuits such as FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit). Alternatively, at least a portion of the diagnostic device 100 may also be constructed using analog circuits.

[0056] Back Figure 1 The diagnostic device 100 is configured to include a preprocessing unit 30, a storage unit 40, a feature extraction unit 50, and a damage state diagnosis unit 60. The functions of each part can be implemented through at least one of software processing and hardware processing executed by the CPU 101. The functions and operations of each part of the diagnostic device 100 will be described below.

[0057] (Preprocessing Section 30)

[0058] The preprocessing unit 30 acquires the output signal of the sensor 20 throughout the entire period of multiple rotations of the rotating ring 12, thereby generating a vibration waveform. In this embodiment, the preprocessing unit 30 generates a displacement vibration waveform in terms of displacement based on the displacement signal detected by the sensor 20. Alternatively, the preprocessing unit 30 may also generate a velocity vibration waveform in terms of velocity based on the velocity signal detected by the sensor 20, and may also generate an acceleration vibration waveform in terms of acceleration based on the acceleration signal detected by the sensor 20.

[0059] (Storage Section 40)

[0060] The storage unit 40 stores the vibration waveform (e.g., displacement vibration waveform) generated by the preprocessing unit 30.

[0061] (Feature extraction unit 50)

[0062] The feature extraction unit 50 extracts multiple feature quantities from the vibration waveform (e.g., displacement vibration waveform) stored in the storage unit 40. In this specification, "feature quantity" refers to a quantity that represents the characteristics of the vibration waveform (e.g., displacement vibration waveform) as a quantitative value.

[0063] Several characteristic quantities include the peel length D in the circumferential direction of the rolling bearing 10 (hereinafter also referred to as "peel length D"), the number of times N that the rolling element 13 passes through the peel during one rotation of the rotating ring 12 (i.e., the rotation period of the rotating ring 12) (hereinafter also referred to as "peel pass number N"), and the index V representing the amplitude dispersion of the vibration waveform (hereinafter also referred to as "dispersion index V"). The definition and extraction method of each characteristic quantity are explained below.

[0064] (1) Peeling length D

[0065] Figure 3 This is a diagram showing an example of a displacement vibration waveform. Figure 3 The diagram shows the displacement vibration waveform of the raceway surface of the retaining ring 11 during a peeling process. Figure 3 The vertical axis represents the displacement of the vibration, and the horizontal axis represents time.

[0066] like Figure 3 As shown, when the rolling element 13 enters the peeling process on the fixed ring 11, the displacement vibration waveform has a positive peak. Furthermore, when the rolling element 13 detaches from the peeling process, the displacement vibration waveform has a negative peak. Additionally, compared to... Figure 3 Conversely, there are also cases where the displacement vibration waveform has a negative peak when the rolling element 13 enters the peeling process, and a positive peak when the rolling element 13 detaches from the peeling process. In either case, the positive and negative peaks accompanying the rolling element 13's entry and detachment from the peeling process appear in the displacement vibration waveform at the pitch interval of the rolling element 13. Furthermore, the amplitude threshold used to detect entry and detachment from the peeling process can be determined, for example, based on the quartile of the vibration waveform amplitude or a multiple of the effective value of the normal value.

[0067] If the operating speed of the rolling bearing 10 is constant, the peel length D can be estimated based on the time difference between the moment when the rolling element 13 enters the peel and the moment when the rolling element 13 leaves the peel. Furthermore, the number of rolling elements 13 passing through the peel (hereinafter also referred to as "number of rolling elements passing through") can be estimated based on the estimated peel length D.

[0068] Specifically, such as Figure 3 As shown, when the peel length D is less than or equal to the pitch interval of the rolling elements 13, the number of rolling elements passing through is 0 to 1. Although the illustration is omitted, when the peel length D exceeds the pitch interval of the rolling elements 13, the number of rolling elements passing through is 1 to 2, and there may always be rolling elements 13 that cannot withstand the load. Therefore, by comparing the peel length D with the pitch interval of the rolling elements 13, the number of rolling elements passing through can be estimated.

[0069] (2) Number of peeling passes N

[0070] Figure 4 and Figure 5 This is a diagram showing an example of the displacement vibration waveform during the time it takes for the rotating ring 12 to rotate one revolution. Figure 4 The raceway surface of the fixed ring 11 generates a displacement vibration waveform during peeling. Figure 5 The raceway surface of the rotating ring 12 generates a displacement vibration waveform during peeling. Figure 4 and Figure 5 The vertical axis represents the displacement of the vibration, and the horizontal axis represents the number of rotations of the rotating ring 12.

[0071] like Figure 4 As shown, when the fixed ring 11 undergoes a peel, in the displacement vibration waveform, a pair of positive and negative peaks generated by the rolling element 13 entering and leaving the peel appear at the pitch interval of the rolling element 13. It can be seen that the multiple positive peaks appearing at the pitch interval of the rolling element 13 have approximately constant magnitudes (amplitudes), and the multiple negative peaks appearing at the pitch interval of the rolling element 13 have approximately constant magnitudes (amplitudes).

[0072] like Figure 5 As shown, even if the rotating ring 12 experiences a peel, in the displacement vibration waveform, the positive and negative peaks generated by the rolling element 13 entering and exiting the peel also appear at the pitch interval of the rolling element 13. However, compared with... Figure 4 The difference is that the pair of positive and negative peaks generated during the peeling of the rolling element 13 only occur when the peeling on the rotating ring 12 enters the load ring. Furthermore, compared to... Figure 4 The difference is that multiple positive peaks appearing at the pitch interval of the rolling element 13 cause amplitude modulation, while multiple negative peaks appearing at the pitch interval of the rolling element 13 cause amplitude modulation.

[0073] Figure 6 This is a schematic diagram showing the load ring of the rolling bearing 10. Figure 6 In this configuration, the rotating ring 12 rotates together with the rotating shaft of the mechanical equipment, and multiple rolling elements 13 roll between the rotating ring 12 and the fixed ring 11. At this time, each rolling element 13 rotates on its own axis while revolving around the central axis.

[0074] In this state, when a radial load is applied to the stationary ring 11, the load is transmitted from the stationary ring 11 to the rotating ring 12 via the rolling elements 13. Within the rolling bearing 10, the load is shared by some of the rolling elements 13. Figure 6 The black arrows in the diagram indicate the load borne by each rolling element 13 (rolling element load). The magnitude of the load borne by each rolling element 13 varies depending on its position. The so-called "load ring" refers to the range of load borne by the rolling element 13.

[0075] When the rotating ring 12 peels off, some of the rolling elements 13 in the load ring enter the peeling process in sequence and then detach from it. Therefore, in the displacement vibration waveform, a pair of positive and negative peaks appear at the pitch interval of the rolling elements 13.

[0076] Here, the number of peeling passes N is calculated by counting the number of peaks (e.g., positive peaks) of the rolling element 13 when it enters the peeling process, contained in the varying vibration waveform during the rotation cycle of the rotating ring 12. Alternatively, the number of peeling passes N can also be calculated by counting the number of peaks (e.g., negative peaks) of the rolling element 13 when it detaches from the peeling process, contained in the varying vibration waveform during the rotation cycle of the rotating ring 12.

[0077] Then, based on the calculated number of peeling passes N, it can be inferred whether the peeling occurred on the fixed ring 11 or the rotating ring 12. Specifically, when the number of peeling passes N is equal to the number of times the rolling element 13 passes through an observation point (e.g., the lowest point of the fixed ring 11) during one rotation of the rotating ring 12, it can be inferred that the peeling occurred on the fixed ring 11 (see reference). Figure 4 ).

[0078] On the other hand, when the peeling passes through the number N and an observation point of the rotating ring 12 at the load ring of the rolling bearing 10 (reference) Figure 6 When the number of contacts between the inner and outer rings of the rotating ring 12 and the rolling element 13 is equal, it can be inferred that peeling has occurred on the rotating ring 12 (refer to...). Figure 5 ).

[0079] Furthermore, by applying the same method, it can be inferred that a peel has occurred on the rolling element 13. Specifically, when the peel occurs at an observation point of a rolling element 13 within the time of one revolution of the rotating ring 12 (reference), the peel occurs at the load ring of the rolling bearing 10. Figure 6 If the number of times the rolling element 13 contacts the fixed ring 11 and the rotating ring 12 is equal, it can be inferred that peeling has occurred on the rolling element 13.

[0080] In addition, "equal number of times" in this specification includes cases where the number of times is exactly the same, as well as cases where there is a slight error but the number of times is substantially the same.

[0081] Therefore, based on the number of peeling passes N, it can be deduced which of the fixed ring 11, rotating ring 12, and rolling element 13 has peeled. The threshold for estimating the location of peeling is given by the following equations (1) to (3). Equation (1) represents the theoretical value of the number of peeling passes N when the fixed ring 11 peels. Equation (2) represents the theoretical value of the number of peeling passes N when the rotating ring 12 peels. Equation (3) represents the theoretical value of the number of peeling passes N when the rolling element 13 peels.

[0082] [Number 1]

[0083] Here, Z represents the number of rolling elements 13, dp represents the pitch circle diameter of the rolling element 13, dw represents the diameter of the rolling element 13, α represents the contact angle, and θ represents the angle of the load ring. Furthermore, these specifications correspond to the bearing model and are pre-stored in the storage device 105 (reference). Figure 2 )middle.

[0084] The theoretical value of the number of peeling passes N when the fixed ring 11 peels corresponds to an embodiment of the "first threshold", the theoretical value of the number of peeling passes N when the rotating ring 12 peels corresponds to an embodiment of the "second threshold", and the theoretical value of the number of peeling passes N when the rolling element 13 peels corresponds to an embodiment of the "third threshold".

[0085] By determining which of the three thresholds given by equations (1) to (3) the peeling number N extracted from the displacement vibration waveform of one rotation is equal to, the location of peeling can be estimated.

[0086] (3) Discrete index V

[0087] Before explaining the dispersion index V, we will first explain one of the damage modes of the rolling bearing 10, namely "pitch gap peeling". Figure 7 This is a schematic diagram used to illustrate pitch interval stripping. Figure 7 This illustrates the situation where pitch gap peeling occurs on the raceway surface of the rotating ring 12.

[0088] If the rolling bearing 10 continues to operate after a peel occurs on the raceway surface of the rotating ring 12, the damage will progress, such as... Figure 7 As shown, multiple peels may sometimes occur at the pitch intervals of the rolling elements 13. In this specification, the multiple peels occurring at the pitch intervals of the rolling elements 13 are referred to as "pitch interval peels". Pitch interval peels may also occur on the retaining ring 11.

[0089] Figure 8 and Figure 9 This is a diagram showing an example of the displacement vibration waveform during the time it takes for the rotating ring 12 to rotate 4 times. Figure 8 It is the displacement vibration waveform of the raceway surface of the fixed ring 11 when the pitch interval peels off. Figure 9 It is the displacement vibration waveform when the raceway surface of the rotating ring 12 produces pitch interval peeling. Figure 8 and Figure 9 The vertical axis represents the displacement of the vibration, and the horizontal axis represents the number of rotations of the rotating ring 12.

[0090] like Figure 8 As shown, when the fixing ring 11 experiences pitch-interval peeling, a peeling occurs between the fixing ring 11 and the fixing ring 11 (see reference). Figure 4 Similarly, in the displacement vibration waveform, a pair of positive and negative peaks will appear at the pitch interval of the rolling element 13. Therefore, the number of peeling passes N when the fixed ring 11 produces pitch interval peeling is equal to the number of peeling passes N when the fixed ring 11 produces one peeling.

[0091] However, if we focus on the size (amplitude) of the wave peaks when the rolling element 13 enters the peeling process, it can be seen that there is a size dispersion among the multiple wave peaks when the fixed ring 11 produces pitch-interval peeling, which is different from the case when the fixed ring 11 produces a single peeling. This dispersion is due to the different sizes (e.g., circumferential width) of the multiple peelings produced on the fixed ring 11, which causes a deviation in the timing of the rolling element 13 entering multiple peelings.

[0092] like Figure 9 As shown, when pitch gap peeling occurs on the rotating ring 12, it is the same as the case where one peeling occurs on the rotating ring 12 (see reference). Figure 5 Similarly, for each rotation of the rotating ring 12, during the period when the rotating ring 12 enters the load ring, a pair of positive and negative peaks will appear on the displacement vibration waveform at the pitch interval of the rolling element 13. Therefore, the number of peeling passes N when pitch interval peeling occurs on the rotating ring 12 is equal to the number of peeling passes N when a single peel occurs on the rotating ring 12.

[0093] In addition, a peeling occurs with the rotating ring 12 (see reference). Figure 5 Similarly, in the displacement vibration waveform of each rotation, the multiple positive peaks generated when the rolling element 13 enters the peeling process are amplitude modulated, and the multiple negative peaks generated when the rolling element 13 leaves the peeling process are also amplitude modulated.

[0094] Here, from Figure 9 In the displacement vibration waveform shown, the maximum value of the peak (e.g., positive peak) when the rolling element 13 enters the stripping phase is extracted for each rotation, and the maximum value of the peak corresponding to 4 rotations is compared. Figure 9 The four circles on the positive side indicate the maximum value of the positive peak under each rotation. Figure 9 It can be seen that the maximum value of the positive peak corresponding to 4 rotations is discrete. Furthermore, Figure 9 The four circles on the negative side indicate the maximum value of the peak (e.g., negative peak) when the rolling element 13 disengages from the peel during each rotation. It can be seen that the maximum value of the negative peak corresponding to the four rotations is also discrete. This discreteness of the maximum value of the peak is due to the different sizes (e.g., circumferential width) of the multiple peels generated on the rotating ring 12, which causes deviations in the timing of the rolling element 13 entering multiple peels within the load ring.

[0095] In this embodiment, the degree of dispersion of the amplitude in the displacement vibration waveform is extracted as the "dispersion index V". The dispersion index V can be obtained by following the steps below.

[0096] First, in the displacement vibration waveform corresponding to n rotations (n ​​is an integer greater than 2), extract the maximum value ai of the positive peak for each rotation (i is the number of rotations, 1≤i≤n). Next, calculate the average value am of the extracted maximum values ​​a1 to an of the positive peaks corresponding to n rotations. Figure 10 The diagram shows the displacement vibration waveform (n=2) corresponding to two rotations when the pitch interval peels off on the fixed ring 11. The feature extraction unit 50 extracts the maximum positive peak heating value a1 of the first rotation and the maximum positive peak heating value a2 of the second rotation from the displacement vibration waveform corresponding to the two rotations, and calculates the average value am of the two extracted maximum values ​​a1 and a2 (am=(a1+a2) / 2).

[0097] Figure 11 The displacement vibration waveform (n=2) corresponding to two rotations when the pitch interval peels off on the rotating ring 12 is shown. The feature extraction unit 50 extracts the maximum value a1 of the positive peak of the first rotation and the maximum value a2 of the positive peak of the second rotation from the displacement vibration waveform corresponding to the two rotations, and calculates the average value of the two extracted maximum values ​​a1 and a2 (am=(a1+a2) / 2).

[0098] Finally, the feature extraction unit 50 substitutes the number of rotations n of the displacement vibration waveform to be evaluated, the maximum value a1 to an of the positive peaks obtained from the displacement vibration waveform for each rotation, and the average value am of the above values ​​into the following formula (4) to calculate the discrete index V.

[0099] [Number 2]

[0100] The greater the dispersion of the maximum value ai of the wave crest per rotation, the larger the value of the dispersion index V. Therefore, the magnitude of the dispersion index V can be used to determine whether a peeling or pitch interval peeling has occurred. Specifically, a threshold Vth for determining pitch interval peeling is pre-set through experiments or simulations. By comparing the dispersion index V extracted from the displacement vibration waveform with the threshold Vth, it can be determined whether a peeling or pitch interval peeling has occurred. The method for setting the threshold Vth will be described in detail later. The threshold Vth corresponds to an embodiment of the "fourth threshold".

[0101] After the feature extraction unit 50 extracts multiple feature quantities (peeling length D, peeling pass number N, and dispersion index V) from the displacement vibration waveform, it outputs the extracted feature quantities to the damage state diagnosis unit 60.

[0102] (Damage Condition Diagnosis Department 60)

[0103] The damage condition diagnosis unit 60 diagnoses the damage condition of the rolling bearing 10 based on multiple feature quantities (peeling length D, peeling pass number N, and dispersion index V) given by the feature quantity extraction unit 50.

[0104] Figure 12 This is a flowchart illustrating the damage condition diagnosis and processing flow of the damage condition diagnosis unit 60. For example... Figure 12 As shown, the damage condition diagnosis unit 60 first determines, through step (hereinafter referred to as "S") 01, whether the number of peeling passes N has been extracted from the displacement vibration waveform. When the number of peeling passes N is 0, the determination in S01 is no. In this case, the damage condition diagnosis unit 60 presumes that the fixed ring 11, rotating ring 12, and rolling element 13 have not peeled. Therefore, the damage condition diagnosis unit 60 diagnoses, through S15, that the rolling bearing 10 is normal (undamaged).

[0105] On the other hand, when the number of peeling passes N > 0, S01 determines it as yes. In this case, the damage condition diagnosis unit 60 estimates that peeling has occurred in any of the fixed ring 11, rotating ring 12, and rolling element 13. Therefore, the damage condition diagnosis unit 60 estimates the location and number of peelings based on multiple characteristic quantities D, N, and V.

[0106] Specifically, in S02, the damage condition diagnosis unit 60 estimates the location of the peeling based on the number of peeling passes N. In S02, the number of peeling passes N is compared with a threshold given by equation (3). This threshold represents the theoretical value of the number of peeling passes N when peeling occurs in the rolling element 13. When the number of peeling passes N is equal to the threshold given by equation (3), S02 determines that it is true. In this case, the damage condition diagnosis unit 60 diagnoses that peeling has occurred in the rolling element 13 (i.e., damage to the rolling element 13) in S14.

[0107] On the other hand, if the number of peeling passes N is inconsistent with the threshold given by equation (3) (no in S02), the damage condition diagnosis unit 60 assumes that peeling has occurred in either the fixed ring 11 or the rotating ring 12. Subsequently, the damage condition diagnosis unit 60 proceeds to S03 to estimate the number of peelings.

[0108] In S03, the damage condition diagnosis unit 60 compares the dispersion index V with the threshold Vth. When the dispersion index V is greater than the threshold Vth (yes in S03), the damage condition diagnosis unit 60 presumes that pitch interval peeling has occurred. On the other hand, when the dispersion index V is less than the threshold Vth (no in S03), the damage condition diagnosis unit 60 presumes that a peeling has occurred.

[0109] When it is presumed that pitch interval peeling has occurred (S03 is yes), the damage status diagnosis unit 60 enters S11 to presumably determine the location of the pitch interval peeling. In S11, the number of peeling passes N is compared with the thresholds given by equations (1) and (2). The threshold given by equation (1) represents the theoretical value of the number of peeling passes N when peeling occurs in the fixed ring 11. The threshold given by equation (2) represents the theoretical value of the number of peeling passes N when peeling occurs in the rotating ring 12.

[0110] In S11, when the number of peeling passes N is equal to the threshold given by equation (1), the damage state diagnosis unit 60 diagnoses that the fixed ring 11 is damaged and pitch interval peeling occurs on the fixed ring 11 in S12. In S11, when the number of peeling passes N is equal to the threshold given by equation (2), the damage state diagnosis unit 60 diagnoses that the rotating ring 12 is damaged and pitch interval peeling occurs on the rotating ring 12 in S13.

[0111] Returning to S03, when it is estimated that a peel has occurred (S03 is not), the damage condition diagnosis unit 60 proceeds to S04 to estimate the number of rolling elements passing through. In S04, the peel length D is compared with the pitch interval of the rolling elements 13. When the peel length D is less than or equal to the pitch interval of the rolling elements 13 (S04 is not), the damage condition diagnosis unit 60 estimates that the number of rolling elements passing through is 0 to 1. Then, the damage condition diagnosis unit 60 proceeds to S05 to estimate the location of a peel. In S05, the number of peel passes N is compared with the threshold given by equations (1) and (2). In S05, when the number of peel passes N is equal to the threshold given by equation (1), the damage condition diagnosis unit 60 diagnoses in S06 that the fixed ring 11 is damaged and a peel has occurred on the fixed ring 11. Furthermore, it diagnoses that the number of rolling elements passing through the peel is 0 to 1.

[0112] In S05, when the number of peeling passes N is equal to the threshold given by equation (2), the damage state diagnosis unit 60 diagnoses in S07 that the rotating ring 12 has been damaged and a peel has occurred on the rotating ring 12. Furthermore, it is diagnosed that the number of rolling elements passing through the peel is 0 to 1.

[0113] Returning to S04, when the peel length D is greater than the pitch interval of the rolling element 13 (S04 determines this to be true), the damage condition diagnosis unit 60 estimates that the number of rolling elements passing through is 1 to 2. Subsequently, the damage condition diagnosis unit 60 proceeds to S08 and estimates a peel location. In S08, the number of peel passages N is compared with the threshold values ​​given by equations (1) and (2). If the number of peel passages N is equal to the threshold value given by equation (1) in S08, the damage condition diagnosis unit 60 diagnoses in S09 that the fixed ring 11 has been damaged and a peel has occurred on the fixed ring 11. Furthermore, it diagnoses that the number of rolling elements passing through this peel location is 1 to 2.

[0114] If the number of peeling passes N in S05 is equal to the threshold given by equation (2), the damage state diagnosis unit 60 diagnoses in S10 that the rotating ring 12 has been damaged and a peel has occurred on the rotating ring 12. Furthermore, it is diagnosed that the number of rolling elements passing through the peel is 1 to 2.

[0115] The damage status diagnosis unit 60 outputs damage status data indicating the diagnosis results. On one hand, the damage status data is transmitted via the I / F device 104 (reference). Figure 2 The data is sent to an external monitoring terminal. Operators can then use the estimated results displayed on the monitoring terminal to determine whether to continue operating the machinery.

[0116] in addition, Figure 12 In this case, the method is configured to determine whether it is a peel or a pitch interval peel based on the discrete index V, and then determine whether the peel occurs on the fixed ring 11 or the rotating ring 12 based on the number of peel passes N. However, it can also be configured to first determine whether the peel occurs on the fixed ring 11 or the rotating ring 12 based on the number of peel passes N.

[0117] <Effect>

[0118] As explained above, according to this embodiment, multiple feature quantities (peeling length D, peeling pass number N, and dispersion index V) are extracted from the vibration waveform of the rolling bearing 10. By comparing the extracted multiple feature quantities with a threshold set for each feature quantity based on the specification data of the rolling bearing 10, the damage state of the rolling bearing 10 can be diagnosed with high precision.

[0119] In detail, by comparing the number of peeling passes N with the first to third thresholds given by equations (1) to (3) (the theoretical values ​​of the number of peeling passes N when peeling occurs in the fixed ring 11, rotating ring 12, and rolling element 13 respectively), the location of peeling in the rolling bearing 10 can be estimated. Furthermore, by comparing the dispersion index V with the threshold Vth (fourth threshold), it can be estimated whether a single peel or a pitch interval peel occurs in the rolling bearing 10. Further, by comparing the peeling length D with the pitch interval of the rolling element 13, the number of passing rolling elements can be estimated. Thus, the damage state, representing the degree of damage progression from the occurrence of a single peel on the rolling bearing 10 to the occurrence of a pitch interval peel, can be quantitatively and accurately diagnosed.

[0120] <Example 1>

[0121] The following Example 1 will provide a more detailed description of the damage state diagnosis system of this embodiment.

[0122] Figure 13 The structure and operating conditions of the rolling bearing used in Example 1 are shown. Figure 13 As shown, the rolling bearing 10 is a roller bearing, and the pitch of the rolling elements 13 is 28 mm. The rotational speed of the rotating ring 12 in the rolling bearing 10 is set to 750 revolutions per minute. When a radial load of 90 kN is applied to the rolling bearing 10, the number of times a single observation point of the rotating ring 12 contacts the rolling element 13 within the load ring of the rolling bearing 10 is 3.

[0123] In Example 1, peeling was formed on the raceway surface of the rotating ring 12. Figure 14 The conditions for peeling are shown. For example... Figure 14 As shown, the conditions for peeling include normal conditions and four damage conditions set according to the stages of peeling progress.

[0124] Normal conditions indicate that the rotating ring 12 is free of peeling. Damage condition 1 indicates one peel with a circumferential dimension of 4 mm. Damage condition 2 indicates one peel with a circumferential dimension of 8 mm. Damage condition 3 indicates one peel with a circumferential dimension of 18 mm. Damage condition 4 indicates three peels, each with a circumferential dimension of 18 mm. In other words, damage condition 4 indicates a state of pitch-interval peeling.

[0125] Figure 14 The rightmost column shows the correct values ​​(true values) for the damage state under each condition. The true values ​​contain accurate information related to the location of the peel, the number of peels (one peel / pitch interval peel), and the number of rolling elements passing through.

[0126] In Example 1, for Figure 14 For each of the five conditions shown, a displacement vibration waveform of the rolling bearing 10 is generated based on the output signal of the sensor 20, and multiple feature quantities (peeling length D, peeling pass N, and dispersion index V) are extracted from the generated displacement vibration waveform. Figures 15-17 The feature quantities extracted under various conditions are shown.

[0127] Figure 15 This is a graph showing the number of peeling passes N extracted from the displacement vibration waveform under various conditions. For example... Figure 15 As shown, the number of peeling passes N under normal conditions (no peeling) is 0. The number of peeling passes N under damage conditions 1 to 4 is 3. The number of peeling passes N under damage conditions 1 to 4 is consistent with the number of times the load ring of the rolling bearing 10 contacts the rolling element 13 at an observation point of the rotating ring 12. Therefore, it can be inferred from the number of peeling passes N that the peeling occurred at the rotating ring 12.

[0128] Figure 16This is a graph showing the discrete index V extracted from the displacement vibration waveform under various conditions. For example... Figure 16 As shown, the dispersion index V for damage condition 4 is more than twice as large as that for normal conditions and damage conditions 1-3. According to... Figure 16 It can be seen that the dispersion index V appropriately characterizes the amplitude dispersion difference in the displacement vibration waveform between normal conditions and damage conditions 1-3 (no peeling or one peeling), and damage condition 4 (pitch interval peeling).

[0129] Figure 17 This is a graph showing the peeling length D extracted from the displacement vibration waveform under various conditions. Figure 17 In the diagram, black dots represent the peeling length D extracted from the displacement vibration waveform, and white dots represent... Figure 14 The true value of the peel length is shown. Under any of the damage conditions 1 to 4, the peel length D shows good agreement with the true value.

[0130] As described above, the multiple feature quantities (peeling length D, peeling pass number N, and dispersion index V) extracted from the displacement vibration waveform can accurately characterize the damage state of the rolling bearing 10. Therefore, based on these multiple feature quantities, the damage state of the rolling bearing 10 can be quantitatively and accurately diagnosed.

[0131] <Setting the threshold Vth>

[0132] The following explains how to set the threshold Vth, which is related to the dispersion index V.

[0133] like Figure 16 As shown, the dispersion index V can effectively characterize the amplitude dispersion difference in the displacement vibration waveform under different peeling quantities. Therefore, by appropriately setting the threshold Vth, the dispersion index V can be compared with the threshold Vth, thereby inferring whether a peeling has occurred or a pitch interval peeling has occurred.

[0134] In this embodiment, the threshold Vth is set based on the static displacement when a rolling element 13 is in a stripped state and a radial load is applied to the rolling bearing 10. Figure 18 This is a graph showing the change in the static displacement ratio relative to the amount of peeling. In Figure 18 In this context, the static displacement when a peel occurs on the fixed ring 11 or the rotating ring 12, and a radial load is applied while a rolling element 13 is in the peeled state, is set as the reference value (1.0). The static displacement ratio represents the ratio of the static displacement to the reference value when the number of peels increases to two or more. In addition, two or more peels are equivalent to "pitch interval peel".

[0135] like Figure 18As shown, as the number of peels increases from 1 to 2, the ratio of static displacement increases by approximately two times. However, as mentioned above, when pitch interval peeling occurs, there is a timing deviation in the entry of the rolling element 13 into multiple peels, thus the amplitude of the rolling element 13 when entering the peel will be discrete.

[0136] Therefore, in this embodiment, it is assumed that when the number of peels is 2, the maximum value a1 to a2 of the peak corresponding to n rotations is extracted from the displacement vibration waveform corresponding to n rotations. n The minimum value a in min =min{a1~a n The ratio of the maximum value amax = max{a1~an} to the maximum value a1~an converges within the range of 1 to 2. Further, assuming that the maximum value amax is taken as the midpoint of this range (1.5) and the minimum value amin is taken as 1.0, the maximum values ​​a1~an of the wave peaks corresponding to n rotations excluding the maximum value amax and the minimum value amin are obtained by linear interpolation of the maximum value amax and the minimum value amin. Based on the above assumptions, the discrete index V of the displacement vibration waveform corresponding to n rotations is calculated according to equation (4), and the calculated discrete index V is set as the threshold Vth.

[0137] Figure 19 The result of calculating the dispersion index V is shown when n=4. Figure 19 The maximum values ​​a1 to a4 of the wave peaks corresponding to the 4 rotations shown are obtained based on the assumption that the maximum values ​​a1 to an of the wave peaks corresponding to the n rotations are set. Substituting the maximum values ​​a1 to a4 into equation (4), the dispersion index V = 0.172 is calculated. Therefore, the threshold Vth is set to 0.172. If the dispersion index V extracted from the displacement vibration waveform is greater than 0.172, it is presumed that pitch interval stripping has occurred.

[0138] Additionally, in the above embodiments, such as Figure 16 As shown, the dispersion index V is less than 0.172 for damage conditions 1-3 (with a peeling quantity of 1), and greater than 0.172 for damage condition 4 (with a peeling quantity of 3). Therefore, setting the threshold Vth to 0.172 is reasonable.

[0139] <Other Examples of Composition>

[0140] (1) Correction of the discrete index V

[0141] In the above embodiments, the dispersion index V under normal conditions exhibits a higher value than the dispersion index V under damage conditions 1-3 (reference). Figure 16This is because, under normal conditions without peeling, the vibration of the rolling bearing 10 is more irregular compared to the state with peeling. The phenomenon of increased dispersion index V under normal conditions can be improved by modifying the derivation formula (4) of the dispersion index V.

[0142] Figure 20 and Figure 21 This is a diagram showing an example of the displacement vibration waveform during the time it takes for the rotating ring 12 to rotate 4 times. Figure 20 It is the displacement vibration waveform under normal conditions (without peeling). Figure 21 It is the displacement vibration waveform under damage condition 4 (pitch interval peeling). Figure 20 and Figure 21 The vertical axis represents the vibration displacement, and the horizontal axis represents the number of rotations of the rotating ring 12.

[0143] like Figure 20 As shown, irregular peaks unrelated to the pitch interval of the rolling element 13 appear in the displacement vibration waveform under normal conditions. Therefore, the feature extraction unit 50 extracts the maximum values ​​a1 to a4 of the peaks unrelated to damage from the displacement vibration waveform of each rotation. Therefore, the time intervals t1, t2, and t3 of the peak values ​​appearing in each rotation are inconsistent with the rotation period T of the rotating ring 12.

[0144] In contrast, such as Figure 21 As shown, during the pitch interval stripping, the time intervals t1, t2, and t3 of the peak values ​​a1 to a4 appearing in each rotation are approximately consistent with the rotation period T of the rotating ring 12.

[0145] Therefore, the derivation formula (4) of the discrete index V is modified by using the time interval ti of the maximum value ai of the wave peak in each rotation and the rotation period T of the rotating ring 12. The modified discrete index Vr is given by equation (5).

[0146] [Number 3]

[0147] Where ti represents the time interval between the timing of the occurrence of the maximum value ai of the displacement vibration waveform in the i-th revolution and the timing of the occurrence of the maximum value ai+1 of the displacement vibration waveform in the (i+1)-th revolution. T represents the rotation period of the rotating ring 12, and k represents the adjustment coefficient.

[0148] Figure 22 The graph shows the discrete index Vr calculated using equation (5). Figure 22 The discrepancy index Vr of the above embodiments under normal conditions and damage conditions 1 to 4 is shown. The adjustment coefficient in equation (5) is set to k=3, and the discrepancy index Vr is calculated based on the displacement vibration waveform under each condition.

[0149] like Figure 22 As shown, the dispersion index Vr under normal conditions is smaller than the dispersion index Vr under damage conditions 1–4. Furthermore, compared with… Figure 16 Similarly, the value of the dispersion index Vr under damage condition 4 is higher than the value of the dispersion index Vr under other conditions. Figure 22 In the normal conditions and damage conditions 1-3, the dispersion index Vr is less than the threshold Vth (0.172), while in damage condition 4, the dispersion index Vr is greater than Vth. Therefore, based on the corrected dispersion index Vr, it is possible to infer whether a peeling or a pitch interval peeling has occurred.

[0150] In addition, the adjustment coefficient k in equation (5) can take any value. For example, it can be adjusted so that the dispersion index Vr under normal conditions is less than the threshold Vth.

[0151] (2) Modifications of the damage status diagnosis system

[0152] Figure 23 This is a block diagram illustrating a modified example of the damage condition diagnosis system according to this embodiment. For example... Figure 23 As shown, the damage state diagnosis system involved in this modified example is similar to... Figure 1 The damage condition diagnostic systems shown differ in structure from the diagnostic device 100.

[0153] The diagnostic device 100 in this modification example and Figure 1 The diagnostic device 100 shown differs in that it includes a damage state acquisition unit 70, a data acquisition unit 80, a model generation unit 90, and a learned model 110. The diagnostic device 100 of this modified example is configured to apply the learned model 110 to a vibration waveform (e.g., a displacement vibration waveform) representing the vibration generated when the rolling bearing 10 rotates, and to diagnose the damage state of the rolling bearing 10.

[0154] Specifically, during the rotation of the rolling bearing 10M, the preprocessing unit 30 generates a vibration waveform (e.g., a displacement vibration waveform) based on the output signal of the sensor 20. The preprocessing unit 30 stores the generated vibration waveform in the storage unit 40. The feature extraction unit 50 extracts multiple feature quantities (peeling length D, peeling pass number N, and dispersion index V) from the vibration waveform of the rolling bearing 10M stored in the storage unit 40.

[0155] The damage state acquisition unit 70 acquires damage state data representing the damage state of the rolling bearing 10M. The data acquisition unit 80 acquires multiple feature quantities (peel length D, peel pass number N, dispersion index V) of the vibration waveform of the rolling bearing 10M extracted by the feature quantity extraction unit 50, as well as the damage state data of the rolling bearing 10M. Figure 23The dashed lines in the diagram represent the data flow during learning.

[0156] The model generation unit 90 uses the multiple feature quantities and damage state data acquired by the data acquisition unit 80 as learning data to generate a learned model 110 for diagnosing the damage state of the rolling bearing 10. As long as it is machine learning, the learning method used by the model generation unit 90 to generate the learned model 110 is not particularly limited. For example, machine learning can utilize a convolutional neural network (CNN).

[0157] The damage condition diagnosis unit 60 uses the generated learned model 110 to diagnose the damage condition of the rolling bearing 10. Specifically, the damage condition diagnosis unit 60 inputs multiple feature quantities (peeling length D, peeling pass number N, and dispersion index V) given by the feature quantity extraction unit 50 into the learned model 110 to diagnose the damage condition of the rolling bearing 10.

[0158] (3) Modified example of feature extraction unit 50

[0159] In the above embodiment, the following structure is described: as one of multiple feature quantities, the feature quantity extraction unit 50 extracts the peeling length D in the circumferential direction of the rolling bearing 10 from the vibration waveform stored in the storage unit 40. Alternatively, the feature quantity extraction unit 50 may extract the non-peeling length Dn in the circumferential direction of the rolling bearing 10 instead of the peeling length D.

[0160] In this modified example, the method for extracting the non-peeling length Dn and the diagnostic processing of the damage state using the non-peeling length Dn are explained.

[0161] Figure 24 This is a diagram showing an example of a displacement vibration waveform, which is related to... Figure 3 A comparison chart. Figure 24 The waveform of displacement vibration during peeling is shown on the raceway surface of the retaining ring 11.

[0162] exist Figure 24 In the example, when the rolling element 13 enters the peel on the fixed ring 11, the displacement vibration waveform has a positive peak, and when the rolling element 13 detaches from the peel, the displacement vibration waveform has a negative peak. In the displacement vibration waveform, the pair of positive and negative peaks generated by the rolling element 13 entering and detaching from the peel appear at the pitch interval of the rolling element 13. Furthermore, the amplitude threshold used to detect entering and detaching from the peel can be determined, for example, based on the quartile of the amplitude of the vibration waveform, or a multiple of the effective value of the normal value, etc.

[0163] If the operating speed of the rolling bearing 10 is constant, the non-peeling length Dn can be estimated based on the time difference between the moment when the rolling element 13 enters the peeling process and the moment when the rolling element 13 detaches from the peeling process, as well as the pitch interval of the rolling elements 13. The non-peeling length Dn is equivalent to the difference obtained by subtracting the peeling length D from the pitch interval of the rolling elements 13. Therefore, similarly to the peeling length D, the number of rolling elements 13 passing through the peeling process (the number of rolling elements passing through) can also be estimated based on the estimated non-peeling length Dn.

[0164] Specifically, such as Figure 24 As shown, when the peel length D is below the pitch interval of the rolling elements 13, the non-peel length Dn is 0 or more. When the non-peel length Dn is 0 or more, the number of rolling elements passing through is 0 to 1. Although the illustration is omitted, when the peel length D exceeds the pitch interval of the rolling elements 13, the non-peel length Dn is less than 0. When the non-peel length Dn is less than 0, the number of rolling elements passing through is 1 to 2, and there may always be rolling elements 13 that cannot bear the load. Therefore, by calculating the non-peel length Dn, the number of rolling elements passing through can be estimated.

[0165] In this modified example, the feature extraction unit 50 extracts multiple feature quantities (non-peeling length Dn, peeling pass number N, and dispersion index V) from the displacement vibration waveform and outputs the extracted feature quantities to the damage condition diagnosis unit 60. The damage condition diagnosis unit 60 diagnoses the damage condition of the rolling bearing 10 based on these multiple feature quantities (non-peeling length Dn, peeling pass number N, and dispersion index V).

[0166] Figure 25 This is a flowchart illustrating the damage state diagnosis process in the damage state diagnosis unit 60 involved in this modified example. Figure 25 The flowchart shown is Figure 12 The difference in the flowchart shown is that S04 is replaced with S04A.

[0167] like Figure 25 As shown, when a peel is presumed to exist in S03 (S03 is not), the damage condition diagnosis unit 60 proceeds to S04A to estimate the number of rolling elements passing through. In S04A, the non-peel length Dn is determined with 0 as a reference. When the non-peel length Dn is 0 or more (S04A is not), the damage condition diagnosis unit 60 estimates that the number of rolling elements passing through is 0 to 1. Subsequently, the damage condition diagnosis unit 60 proceeds to S05 to estimate the location of a peel.

[0168] In S04A, when the non-peeling length Dn is less than 0 (S04A is yes), the damage condition diagnosis unit 60 estimates that the number of rolling elements passing through is 1 to 2. Subsequently, the damage condition diagnosis unit 60 proceeds to S08 and estimates the location of a peeling.

[0169] In this modified example, multiple feature quantities (non-peeling length Dn, peeling pass number N, and discrete index V) can also be extracted from the vibration waveform of the rolling bearing 10. The extracted feature quantities are compared with the threshold set for each feature quantity based on the specification data of the rolling bearing 10, thereby accurately estimating the damage state of the rolling bearing 10.

[0170] <Example 2>

[0171] The damage state diagnosis system involved in this modified example will be further described in detail below through Example 2.

[0172] Furthermore, the structure and operating conditions of the rolling bearing used in Example 2 are the same as those in Example 1. Figure 13 The same applies as shown. That is, the rolling bearing 10 is a roller bearing, and the pitch of the rolling elements 13 is 28 mm. The rotational speed of the rotating ring 12 in the rolling bearing 10 is 750 revolutions per minute. When a radial load of 90 kN is applied to the rolling bearing 10, the number of times a single observation point of the rotating ring 12 contacts the rolling element 13 in the load ring of the rolling bearing is 3.

[0173] In Example 2, a peel is formed on the raceway surface of the rotating ring 12. Figure 26 The conditions for peeling are shown in the diagram. For example... Figure 26 As shown, the conditions for peeling include normal conditions and four damage conditions set according to the stages of peeling progress.

[0174] Normal conditions refer to a state where the rotating ring 12 has no peeling and the non-peeling dimension in the circumferential direction is equal to the pitch interval of the rolling element 13, which is 28 mm. Damage condition 1 refers to a state where there is one peeling and the non-peeling dimension in the circumferential direction is 24 mm. Damage condition 2 refers to a state where there is one peeling and the non-peeling dimension in the circumferential direction is 20 mm. Damage condition 3 refers to a state where there is one peeling and the non-peeling dimension in the circumferential direction is 10 mm. Damage condition 4 refers to a state where there are three peelings and the non-peeling dimension in the circumferential direction is 10 mm each. That is, damage condition 4 indicates a state where pitch interval peeling has occurred.

[0175] Figure 26 The rightmost column shows the correct values ​​(true values) for the damage state under each condition. The true values ​​contain accurate information related to the location of the peel, the number of peels (one peel / pitch interval peel), and the number of rolling elements passing through.

[0176] In Example 2, for Figure 26 Each of the five conditions shown generates a displacement vibration waveform of the rolling bearing 10 based on the output signal of the sensor 20, and extracts multiple feature quantities (non-peeling length Dn, peeling pass number N, and dispersion index V) from the generated displacement vibration waveform. Figures 27-29 The figure shows the feature quantities extracted under each condition.

[0177] Figure 27 This is a graph showing the number of peeling passes N extracted from the displacement vibration waveform under various conditions. For example... Figure 27 As shown, the number of peeling passes N under normal conditions (no peeling) is 0. The number of peeling passes N under damage conditions 1 to 4 is 3. The number of peeling passes N under damage conditions 1 to 4 is consistent with the number of times the rotating ring 12 contacts the rolling element 13 in the load ring of the rolling bearing 10 at one observation point. Therefore, it can be inferred from the number of peeling passes N that the peeling occurred in the rotating ring 12.

[0178] Figure 28 This is a graph showing the discrete index V extracted from the displacement vibration waveform under various conditions. For example... Figure 28 As shown, the dispersion index V for damage condition 4 is more than twice as large as that for normal conditions and damage conditions 1-3. According to... Figure 28 It can be seen that the dispersion index V can appropriately characterize the difference in amplitude dispersion in the displacement vibration waveform between normal conditions and damage conditions 1-3 (no peeling or one peeling) and damage condition 4 (pitch interval peeling).

[0179] Figure 29 This is a graph showing the non-stripping length Dn extracted from the displacement vibration waveform under various conditions. Figure 29 In the diagram, the black circle represents the non-stripping length Dn extracted from the displacement vibration waveform, and the white circle represents... Figure 26 The true value of the non-peeling length is shown. Under any of the damage conditions 1 to 4, the non-peeling length Dn is in good agreement with the true value.

[0180] As described above, the multiple feature quantities (non-peeling length Dn, peeling pass number N, and dispersion index V) extracted from the displacement vibration waveform can accurately characterize the damage state of the rolling bearing 10. Therefore, based on these multiple feature quantities, the damage state of the rolling bearing 10 can be diagnosed quantitatively and with high precision.

[0181] It should be considered that the embodiments disclosed herein are exemplary and not limiting in all respects. The scope of this disclosure is not limited by the foregoing description, but is defined by the claims and is intended to cover all modifications falling within the equivalent meaning and scope of the claims.

[0182] Label Explanation

[0183] 10 Rolling bearing, 11 Fixed ring, 12 Rotating ring, 13 Rolling element, 14 Cage, 20 Sensor, 30 Preprocessing unit, 40 Storage unit, 50 Feature extraction unit, 60 Damage state diagnosis unit, 70 Damage state acquisition unit, 80 Data acquisition unit, 90 Model generation unit, 101 CPU, 102 RAM, 103 ROM, 104 I / F device, 105 Storage device, 106 Communication bus, 110 Learned model.

Claims

1. A damage condition diagnostic system, A damage condition diagnosis system is used to diagnose the damage condition of a rolling bearing, indicating the degree of damage progression. The rolling bearing includes a fixed ring, a rotating ring, and a plurality of rolling elements circumferentially spaced at equal pitch intervals between the fixed ring and the rotating ring. The damage condition diagnostic system includes: A sensor for detecting the vibrations generated when the rolling bearing is rotated; as well as A diagnostic device for diagnosing the damage condition of the rolling bearing based on the output signal of the sensor. The diagnostic device includes: A preprocessing unit generates vibration waveforms by acquiring the output signal of the sensor during the time it takes for the rotating ring to rotate multiple times. A feature extraction unit that extracts multiple feature quantities from the vibration waveform; and A damage condition diagnosis unit that diagnoses the damage condition of the rolling bearing based on the multiple feature quantities extracted by the feature quantity extraction unit. The plurality of characteristic quantities include the peel length or non-peel length in the circumferential direction of the rolling bearing, the number of peel passes of each rolling element through the peel within one rotation of the rotating ring, and the dispersion index representing the amplitude dispersion of the vibration waveform.

2. The damage condition diagnosis system as described in claim 1, characterized in that, The damage condition diagnosis unit diagnoses the damage condition of the rolling bearing by comparing each of the plurality of feature quantities with a threshold set for each feature quantity based on the specification data of the rolling bearing.

3. The damage condition diagnosis system as described in claim 2, characterized in that, The feature extraction unit obtains the entry time of the rolling element entering the peeling on the raceway and the exit time of the rolling element leaving the peeling from the vibration waveform, and estimates the peeling length based on the time difference between the obtained entry time and exit time. The damage condition diagnosis unit estimates the number of rolling elements passing through the peel by comparing the peel length estimated by the feature extraction unit with the pitch interval of the plurality of rolling elements.

4. The damage condition diagnosis system as described in claim 3, characterized in that, When the peel length estimated by the feature extraction unit is less than or equal to the pitch interval of the plurality of rolling elements, the damage state diagnosis unit estimates that the number of rolling elements passing through is 0 to 1. When the peel length estimated by the feature extraction unit is greater than or equal to the pitch interval of the plurality of rolling elements, the damage state diagnosis unit estimates that the number of rolling elements passing through is 1 to 2.

5. The damage condition diagnosis system as described in claim 2, characterized in that, The feature extraction unit obtains the entry time of the rolling element entering the ring and the exit time of the rolling element from the vibration waveform, and estimates the non-peeling length based on the time difference between the entry time and the exit time, and the pitch interval of the plurality of rolling elements. The damage condition diagnosis unit estimates the number of rolling elements passing through the peel based on the non-peel length estimated by the feature extraction unit.

6. The damage condition diagnosis system as described in claim 5, characterized in that, When the non-peeling length estimated by the feature extraction unit is 0 or more, the damage state diagnosis unit estimates that the number of passing rolling elements is 0 to 1. When the non-peeling length estimated by the feature extraction unit is less than 0, the damage state diagnosis unit estimates that the number of passing rolling elements is 1 to 2.

7. The damage condition diagnosis system as described in claim 2, characterized in that, The feature extraction unit calculates the number of peeling passes by counting the number of wave peaks in the vibration waveform within the rotation cycle of the rotating ring, specifically the wave peaks when the rolling element enters the peeling process or when the rolling element detaches from the peeling process. The damage condition diagnosis unit estimates the location of peeling in the rolling bearing by comparing the number of peeling passes calculated by the feature quantity extraction unit with first to third thresholds. The first threshold is the theoretical value of the number of peeling passes when the fixed ring peels off, the second threshold is the theoretical value of the number of peeling passes when the rotating ring peels off, and the third threshold is the theoretical value of the number of peeling passes when the rolling element peels off.

8. The damage condition diagnosis system as described in claim 7, characterized in that, The damage diagnosis unit presumes that the fixed ring has peeled when the number of peeling passes is equal to the first threshold, presumes that the rotating ring has peeled when the number of peeling passes is equal to the second threshold, and presumes that the rolling element has peeled when the number of peeling passes is equal to the third threshold.

9. The damage condition diagnosis system as described in claim 7 or 8, characterized in that, The first threshold, the second threshold, and the third threshold are set using the number of the plurality of rolling elements in the rolling bearing, the pitch circle diameter of the rolling elements, the diameter of the rolling elements, the contact angle, and the angle of the load ring.

10. The damage condition diagnosis system as described in claim 2, characterized in that, The feature extraction unit extracts the maximum value of the wave peak when the rolling element enters the peeling phase for each rotation from the vibration waveform, calculates the average value of the extracted peak values ​​corresponding to multiple rotations, and calculates the dispersion index based on the maximum value of the peaks corresponding to multiple rotations and the average value. The damage condition diagnosis unit determines whether the rolling bearing has experienced a single peel or a pitch interval peel by comparing the discrete index calculated by the feature extraction unit with a fourth threshold.

11. The damage condition diagnosis system as described in claim 10, characterized in that, The damage condition diagnosis unit presumes that the rolling bearing has experienced a peel when the dispersion index is less than the fourth threshold, and presumes that the rolling bearing has experienced a pitch interval peel when the dispersion index is greater than the fourth threshold.

12. The damage condition diagnosis system as described in claim 10, characterized in that, The feature extraction unit calculates the discrete index based on the maximum value, the average value, the rotation period of the rotating ring, and the time interval between the occurrence of the maximum value of the peak during each rotation.

13. The damage condition diagnostic system as described in any one of claims 10 to 12, characterized in that, The fourth threshold is set based on the static displacement when a load is applied to the rolling bearing in a state where a peel occurs on the fixed ring or the rotating ring, and is based on the ratio of the static displacement to the reference when the peel number changes from 1 to 2.

14. The damage condition diagnosis system as described in claim 1, characterized in that, The diagnostic device further includes: The data acquisition unit acquires the plurality of feature quantities extracted from the vibration waveform generated based on the output signal of the sensor during the rotation of the rolling bearing of the learning object, as well as the damage state data of the rolling bearing of the learning object; and The model generation unit uses the data acquired by the data acquisition unit as learning data to generate a learned model for diagnosing the damage state of the rolling bearing. The damage condition diagnosis unit inputs the multiple feature quantities extracted by the feature quantity extraction unit into the learned model and diagnoses the damage condition of the rolling bearing.

15. A method for diagnosing damage status, A damage condition diagnosis method is used to diagnose the degree of damage progression in a rolling bearing. The rolling bearing includes a fixed ring, a rotating ring, and a plurality of rolling elements circumferentially spaced at equal pitch intervals between the fixed ring and the rotating ring. The method for diagnosing the damage state includes: The step of using sensors to detect the vibrations generated when the rolling bearing is rotated; as well as The step of diagnosing the damage condition of the rolling bearing based on the output signal of the sensor. The diagnostic steps include: The step of generating a vibration waveform by acquiring the output signal of the sensor within the time it takes for the rotating ring to rotate multiple times; The steps of extracting multiple feature quantities from the vibration waveform; and The step of diagnosing the damage state of the rolling bearing based on the extracted multiple feature quantities. The plurality of characteristic quantities include the peel length or non-peel length in the circumferential direction of the rolling bearing, the number of peel passes of each rolling element through the peel within one rotation of the rotating ring, and the dispersion index representing the amplitude dispersion of the vibration waveform. The diagnostic steps include the following steps: comparing each feature quantity with a threshold value set for each feature quantity based on the specification data of the rolling bearing, thereby diagnosing the damage state of the rolling bearing.

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