JP2022157865A - Lubrication defect determination device for roller bearing, lubrication defect determination method, and program - Google Patents

Abstract

To provide a method capable of detecting a sign for burning of a bearing device at relatively low cost.SOLUTION: A lubrication defect determination device for a roller bearing has: normalization means which performs, on a spectrogram generated from a sound generated by the roller bearing, normalization processing along a time direction for each frequency; averaging means which uses values after the normalization processing to perform averaging processing; calculation means which uses values after the averaging processing to calculate a sound parameter; and determination means which determines whether or not the roller bearing is defective in lubrication based upon whether or not the sound parameter exceeds a predetermined threshold.SELECTED DRAWING: Figure 4

Description

TECHNICAL FIELD The present invention relates to a rolling bearing lubrication failure determination device, a lubrication failure determination method, and a program.

Conventionally, rolling bearings installed in mechanical devices such as vehicles are periodically subjected to abnormality diagnosis to detect damage and wear at an early stage, thereby suppressing the occurrence of rolling bearing failures. . Seizure is one of the causes of failure of rolling bearings, and a method capable of detecting seizure as early as possible is desired in order to suppress failure.

One of the causes of seizure in rolling bearings is lack of lubricant used in rolling bearings. For example, Patent Literature 1 discloses prevention of seizure inside the bearing device by detecting lack of oil supplied to the bearing device based on vibration information. Further, Patent Document 2 discloses detection of oil shortage by focusing on the fact that the frequency spectrum of vibration generated in a bearing increases in a wide band when there is an oil shortage.

JP 2017-180819 A JP-A-55-138616

In Patent Document 2, determination is made based on whether or not the frequency spectrum has a similar aspect to white noise. In the case of this method, surface roughening and the like are detected in addition to oil shortage, so there is a problem of erroneous determination. In addition, the methods described in the above-mentioned prior art documents require continuous measurement of rolling bearings, and it is not possible to predict seizure based on measurement results in a relatively short period of time at a certain point in time. difficult. In addition, there is a problem that it is necessary to implement a part for continuous measurement and recording, resulting in high cost.

In view of the above problems, an object of the present invention is to provide a method capable of detecting signs of seizure in rolling bearings at relatively low cost.

In order to solve the above problems, the present invention has the following configuration. That is, a lubrication failure determination device for a rolling bearing,
normalization means for normalizing the spectrogram generated from the sound generated in the rolling bearing along the time direction for each frequency;
Averaging means for performing an averaging process using the normalized values;
calculating means for calculating a sound parameter using the averaged values;
and determination means for determining a lubrication failure in the rolling bearing based on whether the sound parameter exceeds a predetermined threshold.

Moreover, another form of this invention has the following structures. That is, a method for determining the need for lubrication of a rolling bearing,
a normalization step of performing normalization processing along the time direction for each frequency on the spectrogram generated from the sound generated in the rolling bearing;
an averaging step of performing an averaging process using the normalized values;
a calculating step of calculating a sound parameter using the averaged values;
determining a lubrication failure in the rolling bearing based on whether the sound parameter exceeds a predetermined threshold.

Moreover, another form of this invention has the following structures. That is, the program
to the computer,
a normalization step of performing normalization processing along the time direction for each frequency on the spectrogram generated from the sound generated in the rolling bearing;
an averaging step of performing an averaging process using the normalized values;
a calculating step of calculating a sound parameter using the averaged values;
and a determination step of determining a lubrication failure in the rolling bearing based on whether the sound parameter exceeds a predetermined threshold.

The present invention makes it possible to detect signs of seizure in rolling bearings at relatively low cost.

FIG. 1 is a schematic diagram showing an example of an apparatus configuration according to one embodiment of the present invention; The figure which shows the example of the spectrogram handled by this invention. FIG. 4 is a diagram for explaining characteristic sounds of interest in the present invention; 4 is a flowchart of lubrication failure determination processing according to one embodiment of the present invention; 4 is a flowchart of spectrogram generation processing according to an embodiment of the present invention; The figure which shows the test example of the lubrication defect determination process which concerns on this invention. The figure which shows the test example of the lubrication defect determination process which concerns on this invention.

EMBODIMENT OF THE INVENTION Hereafter, the form for implementing this invention is demonstrated with reference to drawings. In addition, the embodiment described below is one embodiment for describing the invention of the present application, and is not intended to be construed as limiting the invention of the present application. Not all configurations are essential configurations for solving the problems of the present invention. Moreover, in each drawing, the same component is indicated by the same reference number to indicate the correspondence.

<First Embodiment>
A first embodiment of the present invention will be described below. In the following description, a ball bearing is used as an example of a rolling bearing, but the present invention is not limited to this, and can be applied to rolling bearings having other configurations. For example, types of rolling bearings to which the present invention can be applied include deep groove ball bearings, angular contact ball bearings, tapered roller bearings, cylindrical roller bearings, and self-aligning roller bearings.

[Occurrence process of burn-in]
First, the seizure generation process that occurs in rolling bearings will be described. In rolling bearings, it is known that seizure occurs in the flow of drive start, lubricant consumption, lubricant shortage, metal contact within the rolling bearing, torque increase, and seizure. Here, the inventors of the present application paid attention to the phenomenon when the lubricant becomes insufficient. Insufficient lubricant causes a state of poor lubrication in the rolling bearing. As a result of investigation and research, it was identified that in a state of poor lubrication, the retainer provided in the rolling bearing may generate vibrations (abnormal vibrations) different from normal vibrations. By capturing the sound when this abnormal vibration occurs (hereinafter referred to as "characteristic sound"), it is possible to determine the lack of lubricant (i.e., poor lubrication), thereby capturing signs of seizure. . In the following description of the present invention, a method for detecting the occurrence of the characteristic sound and catching signs of burn-in will be described.

[Device configuration]
FIG. 1 is a schematic configuration diagram showing an example of the overall configuration of an apparatus according to this embodiment. FIG. 1 shows the configurations of a bearing unit 100 to which the lubrication failure determination method according to the present embodiment is applied, and a lubrication failure determination device 200 that performs lubrication failure determination. FIG. 1 shows a configuration in which one rolling bearing 101 is provided in one bearing unit 100 for the sake of simplification of explanation, but one bearing unit 100 may be provided with a plurality of rolling bearings 101 . . Also, the bearing unit 100 may include parts other than the rolling bearing 101, and only the configuration according to this embodiment is shown here for the sake of simplifying the description.

The rolling bearing 101 rotatably supports the end of a rotating shaft (not shown). The rotating shaft is supported by a housing (not shown) that covers the outside of the rotating shaft via a rolling bearing 101 that is a rotating component. The rolling bearing 101 includes an inner ring 104 that is a rotating ring that is fitted on the rotating shaft, an outer ring 102 that is a fixed ring that is fitted on the housing, and a plurality of rolling elements 103 arranged between the inner ring 104 and the outer ring 102 . It has a plurality of balls (rollers) and a retainer 105 that retains the rolling elements 103 so that they can roll. Here, a configuration in which the outer ring 102 is fixed will be described as an example, but a configuration in which the inner ring 104 is fixed may also be used. Also, the guide method of the retainer 105 is not particularly limited, and may be any of outer ring guide, inner ring guide, or rolling element guide.

Further, in rolling bearing 101, friction between inner ring 104 and rolling elements 103 and between outer ring 102 and rolling elements 103 is reduced by a predetermined lubrication method. Although the lubrication method is not particularly limited, for example, grease lubrication, oil lubrication, or the like is used. Also, the type of lubricant is not particularly limited. The lubrication failure determination method according to the present embodiment is particularly effective for grease lubrication or oil lubrication methods other than oil bath lubrication (oil/air, oil mist, splashing, coating, etc.). Oil lubrication methods other than oil bath lubrication may cause lubrication failure in rolling bearings due to deterioration of the lubricating surface and lubricant, device failure, etc. Therefore, the lubrication failure determination method according to the present embodiment can be applied to these. is.

The bearing unit 100 is provided with a sound detection section 106 that detects a sound generated from the rolling bearing 101 during operation of the rolling bearing 101 . The sound detection unit 106 includes a microphone and the like. Note that the sound detection unit 106 is not limited to a configuration in which it is fixedly installed at the inspection position inside the bearing unit 100, and may be installed at a position for detecting the sound generated by the rolling bearing 101 when lubrication failure is determined. good. Therefore, the sound detection section 106 may be detachable or movable with respect to the bearing unit 100 .

The lubrication defect determination device 200 may be realized by, for example, an information processing device including a control device, a storage device, and an input/output device (not shown). The control device may be composed of a CPU (Central Processing Unit), an MPU (Micro Processing Unit), a DSP (Digital Single Processor), a dedicated circuit, or the like. The storage device is composed of volatile and non-volatile storage media such as HDD (Hard Disk Drive), ROM (Read Only Memory), RAM (Random Access Memory), etc., and inputs and outputs various information according to instructions from the control device. It is possible. The input/output device is composed of a speaker, a light, or a display device such as a liquid crystal display, and notifies the user according to an instruction from the control device. The notification method by the input/output device is not particularly limited. For example, it may be an auditory notification by voice or a visual notification by screen output. Also, the input/output device may be a network interface having a communication function, and may perform communication processing by transmitting data to an external device (not shown) via a network (not shown). The content of the output processing here is not limited to notification when an abnormality is detected, and may include notification that the rolling bearing 101 is normal (that is, good lubrication).

The lubrication defect determination device 200 includes a sound acquisition section 201 , a spectrogram generation section 202 , a parameter generation section 203 , a determination section 204 , an information storage section 205 and an output processing section 206 . Each part may be implemented by reading out a corresponding program from the storage device and executing it by the control device described above. Furthermore, various operations such as notification operation and communication operation may be performed by the control device controlling the input/output device.

The sound acquisition unit 201 acquires sounds detected by the sound detection unit 106 . The sound acquisition unit 201 may perform A/D (Analog/Digital) conversion by an AD converter (not shown), signal amplification processing by an amplifier (not shown), and filtering processing, depending on the content of the sound. . In the filtering process, an LPF (Low Pass Filter) that removes predetermined high frequency components and an HPF (High Pass Filter) that removes predetermined low frequency components from the sound acquired by the sound detection unit 106 are used. processing may be performed. Further, in order to prevent generation of aliasing signals, an AD converter (not shown) may be configured to use an antialiasing filter that removes a predetermined high frequency component. The sound acquisition unit 201 outputs the acquired sound information to the spectrogram generation unit 202 and the information storage unit 205 . A spectrogram generator 202 generates a spectrogram using the acquired sound information. A method of generating the spectrogram will be described later.

The parameter generation unit 203 uses the spectrogram generated by the spectrogram generation unit 202 to generate sound parameters used for determination processing by the determination unit 204 . A method of generating sound parameters will be described later. The determination unit 204 uses the sound parameter generated by the parameter generation unit 203 and the threshold value stored in the information storage unit 205 to determine whether or not there is lubrication failure (that is, whether or not there is a sign of seizure). or). In the present embodiment, when the sound parameter exceeds the threshold, it is assumed that a characteristic sound indicative of lubrication failure is occurring.

The information storage unit 205 stores and manages sound information acquired by the sound acquisition unit 201 and various types of information such as threshold values used in determination. The output processing unit 206 notifies the determination result of the determination unit 204 or notifies a predetermined notification destination. The notification method may be configured to be arbitrarily selectable by the user of the lubrication defect determination device 200 .

[Generation of spectrogram and parameters]
FIG. 2 shows an example of a spectrogram generated from a raw waveform of sound acquired by the sound acquisition unit 201 according to this embodiment. In FIG. 2, the horizontal axis indicates time [s] and the vertical axis indicates frequency [kHz]. Also, as shown by the gradation on the right side, the gradation indicates the signal strength [dB] with respect to the frequency.

In the example of FIG. 2, 0 to 50 kHz is shown as the frequency band for generating the spectrogram. A spectrogram of the frequency band may be generated.

The spectrogram generation unit 202 divides the raw waveform of the sound acquired by the sound acquisition unit 201 into predetermined unit times, and then performs FFT (Fast Fourier Transform) processing. The FFT processing uses the following formula (1). Although the predetermined unit time here is not particularly limited, it is defined in advance.

Furthermore, the spectrogram generation unit 202 calculates a power spectrum using the following formula (2) based on each value obtained by the above formula (1). The power spectrum is the signal strength for each frequency and corresponds to the shading shown in FIG. |X| indicates the absolute value of X.

By repeatedly performing processing using equations (1) and (2) on the raw waveform of the sound acquired by the sound acquisition unit 201, a spectrogram as shown in FIG. 2 is generated.

Next, the parameter generator 203 normalizes the spectrogram generated by the spectrogram generator 202 in the time direction with respect to each frequency using Equation (3) below.

As the data used when calculating the average value and standard deviation of the power spectrum of each frequency, data of a predetermined time width from a certain time point may be used. For example, the power spectrum average value may be calculated using a moving average.

Furthermore, the parameter generation unit 203 performs convolution processing according to the following equation (4) using f obtained by the above equation (3) and the window function g, thereby averaging the normalized spectrogram . This produces a two-dimensional array, shown in the x and y directions, based on the spectrogram.

Then, the parameter generation unit 203 calculates the average of the absolute values by the following formula (5) using the values of the two-dimensional array obtained by the formula (4). A parameter obtained by this is set as a sound parameter v, and is used in the lubrication failure determination process according to the present embodiment.

[Relationship between occurrence of lubrication failure and characteristic sound]
As described above, the inventors of the present application conducted investigations and studies and found that a certain characteristic sound is generated in association with abnormal vibration of the cage in a state of poor lubrication. It has been found that this characteristic sound has a constant characteristic regardless of the configuration and operating conditions of the rolling bearing. Therefore, regardless of the structure and operating conditions of the rolling bearing, by using a general-purpose threshold value that is set corresponding to the characteristic sound, it is possible to detect the occurrence of the characteristic sound associated with abnormal vibration of the cage, and to detect lubrication failure. can be determined.

3A and 3B are diagrams for explaining characteristic sounds generated in the retainer of interest in the present embodiment. FIG. As in FIG. 2, the horizontal axis indicates time [s] and the vertical axis indicates frequency [kHz]. Also, as shown by the gradation on the right side, the gradation indicates the signal strength [dB] with respect to the frequency. FIG. 3(a) shows a spectrogram of the sound generated when the rolling bearing is operated in a sufficiently lubricated state. FIG. 3(b) shows a spectrogram of the sound generated when the rolling bearing is operated in a state of poor lubrication.

As can be seen by comparing the spectrograms of FIGS. 3(a) and 3(b), the characteristic sound described above is generated in the state of poor lubrication. Focusing on the frequency, this characteristic sound changes in a wide frequency band. Focusing on the signal intensity, the loudness of the characteristic sound increases and decreases irregularly.

It has been found that the characteristic sound of interest in the present embodiment remarkably appears in the frequency band of 20 kHz to 40 kHz. Therefore, it is more desirable for the sound acquisition unit 201 to use a bandpass filter that passes this frequency band. This makes it possible to improve the accuracy and reduce the processing load when extracting characteristic sounds.

[Processing flow]
FIG. 4 is a flow chart of the lubrication failure determination process according to the present embodiment. This process is executed by the lubrication defect determination device 200. For example, a control device (not shown) included in the lubrication defect determination device 200 reads out a program for realizing each part shown in FIG. 1 from the storage device and executes it. It may be realized by

In S<b>401 , lubrication defect determination device 200 acquires sound information generated in rolling bearing 101 via sound detection unit 106 . The length (time width) of the sound information acquired here is not particularly limited. good too.

In S402, lubrication defect determination device 200 generates a spectrogram using the sound information acquired in S401. The details of this step will be described later with reference to FIG.

In S403, the lubrication defect determination device 200 performs normalization processing using the spectrogram generated in S402. Specifically, using Equation (3) described above, each frequency indicated by the vertical axis of the spectrogram is normalized along the time direction.

In S404, the lubrication defect determination device 200 performs an averaging process using the values obtained by the normalization process in S403. Specifically, the spectrogram is averaged in the time direction and the frequency direction using a window function as shown in Equation (4) above.

At S405, the lubrication defect determination apparatus 200 calculates sound parameters using the values of the two-dimensional array obtained by the averaging process at S404. Specifically, the sound parameter v is calculated by calculating the average of the absolute values of the values obtained in S404 using Equation (5) described above.

In S406, the lubrication defect determination device 200 determines whether or not the rolling bearing 101 is in a lubrication defect state by comparing the sound parameter calculated in S405 with the threshold value Th. The threshold Th here is defined in advance corresponding to the characteristic sound indicating the lubrication failure, and is stored in the information storage unit 205 . If the sound parameter is equal to or greater than the threshold Th (YES in S406), the process of lubrication defect determination device 200 proceeds to S407. On the other hand, if the sound parameter is less than the threshold Th (NO in S406), the processing of the lubrication defect determination device 200 proceeds to S408.

In S407, the lubrication defect determination device 200 determines that the rolling bearing 101 to be determined is in the lubrication defect state. Then, the processing of the lubrication defect determination device 200 proceeds to S409.

In S408, the lubrication defect determination device 200 determines that the rolling bearing 101 to be determined is in a good lubrication state. Then, the processing of the lubrication defect determination device 200 proceeds to S409.

In S409, lubrication defect determination device 200 notifies the determination result of S407 or S408. Although the notification method here is not particularly limited, for example, if it is determined that lubrication is defective, an auditory alert may be output, or if it is visually determined that lubrication is defective on the screen A rolling bearing 101 may be shown. Then, this processing flow ends.

(spectrogram generation)
FIG. 5 is a flowchart of processing for generating a spectrogram from sound information according to this embodiment, and corresponds to the step of S402 in FIG.

In S501, the lubrication defect determination device 200 generates a plurality of section data by dividing the sound information acquired via the sound detection unit 106 into predetermined unit times. The predetermined unit time here is preset and held in the information storage unit 205 .

In S502, the lubrication defect determination apparatus 200 performs FFT processing on each of the plurality of section data generated in S501. Specifically, FFT processing is performed using the above equation (1).

In S503, lubrication defect determination device 200 generates a spectrogram using the processing result of S502. Specifically, for each frequency after FFT processing, the power spectrum is calculated using the above formula (2), and arranged in time series corresponding to the time axis and the frequency axis, as shown in FIG. produces a spectrogram. After that, the process proceeds to S403 in FIG.

In the above example, the rolling bearing 101 is diagnosed with poor lubrication, and notified when it is determined that there is poor lubrication (when the sound parameter v exceeds the threshold Th). However, the present invention is not limited to this configuration. For example, a configuration may be used in which a notification is made when the number of times the sound parameter v exceeds the threshold value Th exceeds a certain value.

The method according to the present embodiment is not limited to the guide method of the retainer. In this embodiment, the determination is made by paying attention to the sound generated from the determination target. For example, in the method of making determination based on vibration of the cage, it is necessary to install a sensor for detecting vibration around the rolling bearing. At this time, it is necessary to consider the installation position because the detection accuracy of vibration of the retainer differs depending on the guide method of the retainer. On the other hand, in the present invention, the position where the sound sensor for detecting sound is installed is not affected by the guide method of the retainer, and can be used more versatly.

In addition, as described above, the characteristic sound focused on in the present invention has certain features regardless of the configuration and operating conditions of the rolling bearing. Therefore, it is not necessary to change the setting of the threshold according to the configuration of the rolling bearing and the operating conditions. In addition, since nothing other than the collected sound is required to be input at the time of determination, it is possible to improve the convenience and simplicity at the time of determination.

Further, the determination method of the present invention does not require past measurement results, and can be executed using only sound information of a certain time width to be measured. Therefore, unlike the conventional determination method, it is not necessary to accumulate past measurement results, and determination can be made with a simple configuration. In addition, since it is not necessary to measure the oil film thickness of the lubricant or deterioration of the lubricant, the configuration required for these measurements can be omitted, and a simple configuration can be realized.

[test]
A test using the method according to the present embodiment and the results thereof will be described below. Here, test results based on two test conditions are shown.

(Test 1)
In Test 1, a rolling bearing in a sufficiently lubricated state and a rolling bearing in a state simulating poor lubrication were prepared, and operated under the following conditions to calculate the sound parameters. The test was conducted under the assumption that the test conditions were the same except for the test conditions described below. FIG. 6 is a diagram showing test results.

Test conditions Bearing: deep groove ball bearing (bearing number: 608)
Number of test samples: 47 (No. 1 to No. 47)
Rotation speed: 1800/3600/5760/7200/9600 [min ^-1 ]
Load (axial load): 30 [N]
Lubrication method: No. 1 to No. 8: Apply 0.025 g of lubricant (sufficient lubrication state)
No. 9 to No. 47: Apply 0.025 g of lubricant and wash with benzene (simulating poor lubrication)
Lubricant (ISO viscosity grade): ISO VG32 PAO (poly-α-olefin oil)
Other than rotation speed/lubrication condition, No. 1 to No. 47, and the rotation speed was set as follows using the above five values.
1800 [min ⁻¹ ]: No. 5, 9, 10, 14, 15, 20-22, 42
3600 [min ⁻¹ ]: No. 11, 16, 17, 23-25, 43
5760 [min ⁻¹ ]: No. 3, 6, 12, 18, 19, 26, 27, 44
7200 [min ⁻¹ ]: No. 1, 2, 7, 13, 28-34, 45
9600 [min ⁻¹ ]: No. 4, 8, 35-41, 46, 47

In FIG. 6, the vertical axis indicates the value of the sound parameter, and the horizontal axis indicates the number of the rolling bearing to be tested (test No.). A constant value is set and used as the threshold value Th. As shown in FIG. 6, No. 1, which is sufficiently lubricated, 1 to No. In No. 8, lubrication is poor. 9 to No. 47, the sound parameters are relatively low. By setting the threshold value Th focusing on this, it becomes possible to determine whether or not there is a state of poor lubrication (that is, whether or not there is a sign of abnormality).

(Test 2)
In Test 2, a rolling bearing was prepared in a state simulating a situation in which poor lubrication tends to occur, and the sound parameters were calculated after operating under the following conditions. The test was conducted under the assumption that the test conditions were the same except for the test conditions described below. FIG. 7 is a diagram showing test results.

Test conditions Bearing: tapered roller bearing (bearing number: HR32008XJ)
Number of test samples: 20 (No. 1 to No. 20)
Rotation speed: 2000 [min ^-1 ]
Load (axial load): 50000 [N]
Lubrication method: Soak the inner ring/rolling elements/cage in lubricant for a short time
(Since the lubricant is not supplied while the rolling bearing is in operation, it is assumed that lubrication failure will occur in a short period of time.)
Lubricant (ISO viscosity grade): ISO VG32 machine oil

In FIG. 7, the vertical axis indicates the rate of time until it is determined that lubrication is defective, and the horizontal axis indicates the number (test No.) of the rolling bearing to be tested. At this time, it is defined as follows.
Seizure time: from the start of the test (driving) to the time when seizure occurred in the rolling bearing Lubrication failure determination time: after the start of the test (driving), lubrication failure by the lubrication failure method according to the present embodiment until it is determined that the sound parameter exceeds the threshold

Even if the sound parameter exceeds the threshold before the temperature of the rolling bearing exceeds a predetermined temperature (for example, 40° C.) after the start of the main test, the sound parameter is not treated as having exceeded the threshold. This is because it is determined that the rolling bearing is operating stably after the temperature of the rolling bearing reaches a predetermined temperature after the start of driving. Therefore, even if the sound parameter exceeds the threshold before reaching this predetermined temperature, it is possible that the rise in the sound parameter was due to the erratic motion of the bearing at the start of the test, rather than due to poor lubrication. It is not used for judgment as it is highly sensitive.

Based on the above, the ratio of time until it is determined that there is lubrication failure indicated by the vertical axis in FIG. 7 is derived from the following equation (6). In other words, the lower the value of the time ratio until it is determined that there is lubrication failure, the earlier the lubrication failure was detected before seizure occurred.
(Percentage of time until determination of lubrication failure) = (Lubrication failure determination time) / (Seizure time) x 100 (6)

20 test numbers shown in FIG. 1 to No. 20, 18 test samples (No. 2 to No. 13, No. 15 to No. 20) catch lubrication failure before seizure occurs, and it is possible to determine that the lubrication failure state. did it. In addition, No. 1 and No. For No. 14, an erroneous determination occurred due to electrical noise. No. As for 1, FIG. 7 shows that the abnormality determination was made at the timing of 78% of the burn-in time. However, the timing at which the actual sound parameter exceeded the threshold was 95% of the burn-in time. Also, No. As for 14, FIG. 7 shows that an abnormality determination was made at a timing 18% of the burn-in time. However, in practice, the sound parameters never exceeded the threshold. This is because, according to the analysis of other measurement signals, it was determined that there was a lubrication failure due to sudden metallic contact occurring between the start of the test when the lubrication was sufficiently lubricated and the stable operation.

As described above, according to the present embodiment, it is possible to detect lubrication failure, which is a sign of seizure in a bearing device, at a relatively low cost.

<Other embodiments>
In addition, in the present invention, a program or application for realizing the functions of one or more embodiments described above is supplied to a system or device using a network or a storage medium, and one or more programs in the computer of the system or device It can also be implemented by a process in which the processor reads and executes the program.

It may also be implemented by a circuit that implements one or more functions (for example, ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array)).

As described above, the present invention is not limited to the above-described embodiments, and those skilled in the art can make modifications and applications by combining each configuration of the embodiments with each other, based on the description of the specification and well-known techniques. It is also contemplated by the present invention that it falls within the scope of protection sought.

As described above, this specification discloses the following matters.
(1) normalization means for normalizing a spectrogram generated from a sound generated in a rolling bearing along the time direction for each frequency;
Averaging means for performing an averaging process using the normalized values;
calculating means for calculating a sound parameter using the averaged values;
and determination means for determining a lubrication defect in the rolling bearing based on whether the sound parameter exceeds a predetermined threshold.
According to this configuration, it is possible to detect lubrication failure, which is a sign of seizure in the bearing device, at a relatively low cost.

(2) According to (1), the predetermined threshold value is defined based on a noise caused by vibration of a retainer of the rolling bearing caused by a shortage of lubricant used in the rolling bearing. Lubrication failure determination device described.
According to this configuration, by prescribing the threshold value for determining the lubrication failure based on the sound measured in advance in the state of the lubrication failure of the rolling bearing, the processing load at the time of the lubrication failure determination can be reduced. can be done.

(3) The lubrication failure determination device according to (1) or (2), wherein the predetermined threshold value is a constant value regardless of the configuration or operating conditions of the rolling bearing.
According to this configuration, it is possible to universally determine lubrication failure regardless of the configuration and operating conditions of the rolling bearing.

(4) The normalization means

The lubrication defect determination device according to any one of (1) to (3), wherein the normalization process is performed along the time direction for each frequency shown in the spectrogram using .
According to this configuration, it is possible to calculate the value along the time direction for each frequency in the spectrogram.

(5) the averaging means includes a window function g;

is used to perform the averaging process along the time direction and the frequency direction of the spectrogram.
According to this configuration, it is possible to obtain an average value as a two-dimensional array by convolution operation using the window function g.

(6) The calculation means

The lubrication defect determination device according to (5), wherein the sound parameter is calculated using
According to this configuration, the sound parameter can be calculated using the average value calculated in the two-dimensional array.

(7) Acquisition means for acquiring sound generated by the rolling bearing;
A lubrication defect determination device according to any one of (1) to (6), further comprising generation means for generating a spectrogram from the sound acquired by the acquisition means.
According to this configuration, it is possible to generate a spectrogram that is used to determine lubrication failure, targeting noise generated in the rolling bearing.

(8) Lubrication failure according to (7), wherein the acquiring means performs filtering using a band-pass filter that passes a band of 20 kHz to 40 kHz for the sound acquired from the rolling bearing. judgment device.
According to this configuration, it is possible to determine lubrication failure targeting a specific frequency. Also, the load of frequency analysis can be reduced.

(9) The lubrication defect determination device according to (7) or (8), wherein the acquisition means performs filtering using an anti-alias filter on the sound acquired from the rolling bearing.
According to this configuration, it is possible to suppress the occurrence of aliases and to determine lubrication failure with high accuracy.

(10) The lubrication failure determination device according to any one of (1) to (9), further comprising reporting means for reporting a determination result by the determination means.
According to this configuration, when lubrication failure occurs, it is possible to notify the user at an appropriate timing.

(11) Any one of (1) to (10), wherein the rolling bearing is a deep groove ball bearing, an angular contact ball bearing, a tapered roller bearing, a cylindrical roller bearing, or a self-aligning roller bearing. 1. A lubrication failure determination device according to claim 1.
According to this configuration, lubrication failure can be determined for deep groove ball bearings, angular ball bearings, tapered roller bearings, cylindrical roller bearings, or self-aligning roller bearings.

(12) The lubrication method of the rolling bearing is a grease lubrication method, or an oil lubrication method selected from oil air, oil mist, splashing, and application (1) to ( 11) A lubrication failure determination device according to any one of the above items.
According to this configuration, lubrication failure can be determined for rolling bearing lubrication methods such as a grease lubrication method, or an oil lubrication method such as oil air, oil mist, splashing, or application. .

(13) a normalization step of normalizing the spectrogram generated from the sound generated by the rolling bearing along the time direction for each frequency;
an averaging step of performing an averaging process using the normalized values;
a calculating step of calculating a sound parameter using the averaged values;
and determining whether or not the sound parameter exceeds a predetermined threshold.
According to this configuration, it is possible to detect lubrication failure, which is a sign of seizure in the bearing device, at a relatively low cost.

(14) to the computer,
a normalization step of performing normalization processing along the time direction for each frequency on the spectrogram generated from the sound generated in the rolling bearing;
an averaging step of performing an averaging process using the normalized values;
a calculating step of calculating a sound parameter using the averaged values;
A program for executing a determination step of determining a lubrication failure in the rolling bearing based on whether the sound parameter exceeds a predetermined threshold.
According to this configuration, it is possible to detect lubrication failure, which is a sign of seizure in the bearing device, at a relatively low cost.

DESCRIPTION OF SYMBOLS 100... Bearing unit 101... Rolling bearing 102... Outer ring 103... Rolling element 104... Inner ring 105... Cage 106... Sound detection part 200... Lubrication defect determination apparatus 201... Sound acquisition part 202... Spectrogram generation part 203... Parameter generation part 204... Determination unit 205... Information storage unit 206... Output processing unit

Claims (14)

normalization means for performing normalization processing along the time direction for each frequency on the spectrogram generated from the sound generated in the rolling bearing;
Averaging means for performing an averaging process using the normalized values;
calculating means for calculating a sound parameter using the averaged values;
and determination means for determining a lubrication defect in the rolling bearing based on whether the sound parameter exceeds a predetermined threshold. 2. The lubrication according to claim 1, wherein the predetermined threshold value is defined based on noise caused by vibration of a retainer of the rolling bearing caused by a shortage of lubricant used in the rolling bearing. Defect judgment device. 3. A lubrication defect determination apparatus according to claim 1, wherein said predetermined threshold value is a constant value regardless of the configuration or operating conditions of said rolling bearing. The normalization means

The lubrication defect determination device according to any one of claims 1 to 3, wherein the normalization process is performed along the time direction for each frequency shown in the spectrogram using . the averaging means includes a window function g,

5. The lubrication defect determination device according to claim 4, wherein the averaging process is performed along the time direction and the frequency direction of the spectrogram using . The calculation means is

6. The lubrication defect determination device according to claim 5, wherein the sound parameter is calculated using . Acquisition means for acquiring sound generated by the rolling bearing;
A lubrication defect determination device according to any one of claims 1 to 6, further comprising generating means for generating a spectrogram from the sound acquired by said acquiring means. 8. The lubrication defect determination device according to claim 7, wherein the acquisition means filters the sound acquired from the rolling bearing using a band-pass filter that passes a band of 20 kHz to 40 kHz. 9. A lubrication defect determination apparatus according to claim 7, wherein said acquisition means performs filtering using an anti-alias filter on the sound acquired from said rolling bearing. 10. The lubrication defect determination device according to claim 1, further comprising notification means for notifying the result of determination by said determination means. 11. The rolling bearing according to any one of claims 1 to 10, wherein the rolling bearing is a deep groove ball bearing, an angular contact ball bearing, a tapered roller bearing, a cylindrical roller bearing, or a self-aligning roller bearing. lubrication failure judgment device. A lubrication method for the rolling bearing is a grease lubrication method, or an oil lubrication method selected from oil/air, oil mist, splashing, and application. Lubrication failure determination device according to. a normalization step of performing normalization processing along the time direction for each frequency on the spectrogram generated from the sound generated in the rolling bearing;
an averaging step of performing an averaging process using the normalized values;
a calculating step of calculating a sound parameter using the averaged values;
and determining whether or not the sound parameter exceeds a predetermined threshold. to the computer,
a normalization step of performing normalization processing along the time direction for each frequency on the spectrogram generated from the sound generated in the rolling bearing;
an averaging step of performing an averaging process using the normalized values;
a calculating step of calculating a sound parameter using the averaged values;
A program for executing a determination step of determining a lubrication failure in the rolling bearing based on whether the sound parameter exceeds a predetermined threshold.

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