JP7442390B2 - Bearing inspection equipment and bearing inspection method - Google Patents

Description

The present invention relates to a bearing inspection device and a bearing inspection method.

Conventionally, there is a technique disclosed in, for example, Japanese Patent Laid-Open No. 3-35140 (Patent Document 1) regarding the inspection of bearings using sound. This bulletin describes ``a data output means that detects the amount of displacement and vibration noise of a bearing and outputs data related thereto; A plurality of fuzzy rules as variables and a membership function for each variable are stored, and data regarding the displacement amount and vibration sound from the data output means is used to generate the fuzzy rules according to the fuzzy rules and membership functions. "The present invention is characterized by comprising a fuzzy inference unit that performs fuzzy inference on the state of the bearing."

Japanese Patent Application Publication No. 3-35140

As in Patent Document 1, the configuration that determines the condition of the bearing by acquiring sound requires less space for installing the sensor than the configuration that acquires the vibration of the bearing and makes the determination, and it is possible to use a non-contact method. It has the advantage that judgment is also possible.

On the other hand, in a configuration in which the state of the bearing is determined by acquiring sound, there is a problem in that the accuracy decreases due to the influence of surrounding environmental sounds. In particular, it has been difficult to inspect bearings that rotate at low speeds because the frequency of abnormal noises decreases.

Therefore, an object of the present invention is to provide a bearing inspection device and a bearing inspection method that are highly accurate and can be used in a wide range of applications.

In order to achieve the above object, one of the typical bearing inspection devices of the present invention includes a sound sensor that detects sound generated from a bearing to be inspected, a magnetic sensor that detects magnetism generated by the bearing, and a magnetic sensor that detects the magnetic field generated by the bearing. an analysis section that frequency-analyzes a magnetic signal that is the detection result of the sensor; and an extraction section that uses the result of the frequency analysis to extract a sound signal of the rotation period of the bearing from the sound signal that is the detection result of the sound sensor. Be prepared.
Further, one of the representative bearing inspection methods of the present invention includes a sound detection step of detecting sound generated from a bearing to be inspected, a magnetic detection step of detecting magnetism generated by the bearing, and a detection of the magnetic detection step. The method includes an analysis step of frequency-analyzing the resulting magnetic signal, and an extraction step of extracting a sound signal of the rotation period of the bearing from the sound signal that is the detection result of the sound detection step using the result of the frequency analysis.

According to the present invention, it is possible to provide bearing inspection with high accuracy and a wide range of applications.
Problems, configurations, and effects other than those described above will be made clear by the following description of the mode for carrying out the invention.

FIG. 1 is an explanatory diagram of a bearing inspection device according to an embodiment. FIG. 2 is a flowchart showing the processing procedure of the bearing inspection device. FIG. 3 is a concrete example of the sound signal and the magnetic signal. FIG. 4 is a specific example of the result of frequency conversion of a magnetic signal. FIG. 5 is a diagram showing abnormal sound determination results using the period of the magnetic signal. FIG. 6 is an explanatory diagram of sensor installation. (Part 1) FIG. 7 is an explanatory diagram of sensor installation. (Part 2) FIG. 8 is an explanatory diagram of sensor installation. (Part 3) FIG. 9 is an explanatory diagram when a plurality of bearings are inspected simultaneously.

Embodiments of the present invention will be described below with reference to the drawings. The examples are illustrative for explaining the present invention, and are omitted and simplified as appropriate for clarity of explanation. The present invention can also be implemented in various other forms. Unless specifically limited, each component may be singular or plural.

The position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc. in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

When there are multiple components having the same or similar functions, the same reference numerals may be given different suffixes for explanation. Furthermore, if there is no need to distinguish between these multiple components, the subscripts may be omitted from the description.

FIG. 1 is an explanatory diagram of a bearing inspection device according to an embodiment. The bearing inspection device 30 shown in FIG. 1 is used to inspect the bearings of the escalator 10. The escalator 10 is a type of passenger conveyor that conveys passengers on circulating treads. The escalator 10 is provided with shafts for circulating treads under the floor surface at both ends thereof. This shaft is held by a bearing 20 that is a rolling bearing containing rolling elements. As an example, each of the two shafts is held by two bearings. In FIG. 1, one of the bearings supporting the lower shaft of the escalator 10 is a bearing 20a, and one of the bearings supporting the upper shaft of the escalator 10 is a bearing 20b.

The bearing inspection device 30 includes a magnetic sensor 31, a sound sensor 32, an analysis section 33, an extraction section 34, and a determination section 35. The magnetic sensor 31 detects magnetism generated by the bearing 20a to be inspected and outputs it as a magnetic signal. The sound sensor 32 detects the sound generated from the bearing 20a and outputs it as a sound signal.

The analysis unit 33 analyzes the frequency of the magnetic signal that is the detection result of the magnetic sensor 31. The extraction unit 34 extracts the sound signal of the rotation period of the bearing from the sound signal that is the detection result of the sound sensor 32 using the result of the frequency analysis. As an example, the extraction unit 34 searches for the peak of the period of the magnetic signal in the vicinity of the period estimated from the structure of the bearing 20a, determines the rotation period of the rolling elements and the rotation period of the inner ring, and sets these as the rotation period of the bearing 20a. . In this case, the extraction unit 34 selectively extracts the sound signals generated in the rotation period of the rolling elements and the rotation period of the inner ring.

The determination unit 35 determines the state of the bearing 20a from the extraction result by the extraction unit 34. Specifically, the determination unit 35 determines, among the extraction results obtained by the extraction unit 34, a sound signal whose sound pressure exceeds a predetermined threshold value as an abnormal sound. Further, the determination unit 35 identifies whether the abnormal sound is from a rolling element or an inner race from the cycle of the magnetic signal corresponding to the abnormal sound. The determination unit 35 outputs the determination result to the outside. The output based on the determination result may be only the determination result, or may be output together with other information. Other information includes a magnetic signal detected by the magnetic sensor 31, a sound signal detected by the sound sensor 32, an analysis result by the analysis section 33, a sound signal extracted by the extraction section 34, and the like.

FIG. 2 is a flowchart showing the processing procedure of the bearing inspection device 30. In preparation for starting this processing procedure, a magnetic sensor 31 and a sound sensor 32 are installed on the bearing 20 to be inspected, and the escalator 10 is driven.

When the processing procedure is started, first, the sound sensor 32 detects sound (step S101), and the magnetic sensor 31 detects magnetism (step S102). After that, the analysis unit 33 performs frequency analysis on the magnetic signal that is the output of the magnetic sensor 31 (step S103). The extraction unit 34 extracts the sound signal of the rotation period of the bearing from the sound signal that is the detection result of the sound sensor 32 using the result of the frequency analysis (step S104). The determination unit 35 determines the state of the bearing 20a from the extraction result by the extraction unit 34, outputs the determination result (step S305), and ends the process.

FIG. 3 is a concrete example of the sound signal and the magnetic signal. The sound signal shown in FIG. 3 includes not only sounds originating from the bearing 20 but also environmental sounds. For this reason, it is difficult to extract sounds indicating an abnormality from only sound signals. On the other hand, the magnetic signal shows periodicity including the rotation of the inner ring of the bearing 20 and the rotation of the rolling elements. It is considered that the sound signal also includes a periodic component derived from the rotation of the bearing 20. Therefore, the bearing inspection device 30 specifies the rotation period of the bearing 20 by converting the frequency of the magnetic signal.

FIG. 4 is a specific example of the result of frequency conversion of a magnetic signal. The extraction unit 34 uses the results of the frequency analysis to search for a peak in the period of the magnetic signal near the period estimated from the structure of the bearing 20a. In FIG. 4, the theoretical values of the cycles of the inner ring, rolling elements, and cage determined from the structure of the bearing 20a and the operating speed of the escalator 10 are 0.25 Hz, 0.90 Hz, and 0 Hz, respectively. If a peak value is searched around this and the actual peak value is determined, the actual peak value of the inner ring is 0.24 Hz, the actual peak value of the rolling element is 0.89 Hz, and the actual peak value of the cage is 0.1 Hz.

By extracting the sound signals that occur at a period corresponding to these actual peak values and removing the rest as noise components (environmental sounds), it is possible to selectively extract the sound originating from the bearing 20. If a sound whose sound pressure is equal to or higher than a threshold among sounds originating from the bearing is determined as an abnormal sound, abnormality of the bearing 20 can be determined with high accuracy.

FIG. 5 is a diagram showing abnormal sound determination results using the period of the magnetic signal. In FIG. 5, an abnormality in the sound signal is shown corresponding to the peak of the magnetic signal.

Next, the installation of the sensor will be explained. 6 to 8 are explanatory diagrams of sensor installation. As a common configuration in FIGS. 6 to 8, a bearing 20 is held in a cage 21. Moreover, rolling elements 23 are built in between the retainer 21 and the inner ring 22. Inside the inner ring 22 is a shaft.

In the configuration shown in FIG. 6, the sensor unit 37 is installed in the holder 21 via, for example, grease. The sensor unit 37 has a substrate 36 inside, and a magnetic sensor 31 and a sound sensor 32 are provided on the bearing 20 side of the substrate 36.

In the configuration shown in FIG. 7, a canceling sound sensor 41 is further provided in addition to the configuration shown in FIG. The canceling sound sensor 41 is provided on the substrate 36, and its installation surface is on the opposite side of the sound sensor 32. The purpose of the canceling sound sensor 41 is to detect environmental sounds, and its sound signal is subtracted from the sound signal of the sound sensor 32. Thereby, the influence of environmental sounds can be reduced.

Furthermore, a configuration can be considered in which the canceling sound sensor 41 is bonded to the sensor unit 37, a hole is made in the sensor unit 37 at the bonded position, and the canceling sound sensor 41 is brought out from the sensor unit 37. For example, a hole is made in the upper surface of the sensor unit 37 through which only the canceling sound sensor 41 passes, and only the canceling sound sensor 41 is allowed to peek outside through the hole. This allows the canceling sound sensor 41 to easily detect environmental sounds generated outside the sensor unit 37.

In the configuration shown in FIG. 8, a sensor unit 37a and a sensor unit 37b are installed in the holder 21. The sensor unit 37a has a substrate 36a inside, and the sound sensor 32 is provided on the bearing 20 side of the substrate 36a. The sensor unit 37b has a substrate 36b inside, and the magnetic sensor 31 is provided on the bearing 20 side of the substrate 36b. Note that the sensor unit 37b having the magnetic sensor 31 may be installed in the holder 21 via grease or the like, and the sensor unit 37a having the sound sensor 32 may be installed in the holder 21 with a magnet or the like.

In the explanation so far, the case where one bearing is inspected has been explained as an example, but it is also possible to simultaneously inspect a plurality of bearings that rotate at the same period. FIG. 9 is an explanatory diagram when a plurality of bearings are inspected simultaneously.

As already explained, the escalator 10 has shafts under the floor surface at both ends, and these two shafts rotate at the same period to circulate the treads. Since each shaft is held by one bearing 20 on one side or two bearings 20 on both sides, two to four bearings 20 rotate at the same period. It is also conceivable that a large number of bearings are installed and rotated at the same period.

In order to simplify the explanation, FIG. 9 shows a case where two bearings 20a and 20b are to be inspected, but it is also possible to inspect three, four, or a large number of bearings 20 at the same time.

The bearing inspection device 30a shown in FIG. 9 includes a magnetic sensor 31, a sound sensor 32a, a sound sensor 32b, an analysis section 33, an extraction section 34a, and a determination section 35a. In this configuration, a magnetic sensor 31 and a sound sensor 32a are installed on the bearing 20a. On the other hand, the magnetic sensor 31 is not installed on the bearing 20b, but a sound sensor 32b is installed.

Similar to FIG. 1, the analysis unit 33 performs frequency analysis on the magnetic signal that is the detection result of the magnetic sensor 31. The extraction unit 34a uses the results of the frequency analysis to extract the sound signals of the rotation periods of the bearings 20a and 20b from the plurality of sound signals that are the detection results of the plurality of sound sensors 32a and the sound sensors 32b, respectively. That is, the period of the magnetic signal acquired by the bearing 20a is also used to extract the sound signal of the bearing 20b.

The determination unit 35 determines the states of the bearing 20a and the bearing 20b from the plurality of sound signals. Similar to the configuration shown in FIG. 1, this determination can be made based on whether the sound pressure exceeds a threshold value. It is also possible to compare the extraction results from a plurality of sound signals to determine the presence or absence of an abnormality. For example, if one of the sound signals extracted from the plurality of bearings 20 at the same time is larger than the other sound signals, there is a possibility that an abnormality has occurred in that bearing 20. In particular, since bearings installed on both sides of a shaft are affected by the same shaft, it is easy to determine whether there is an abnormality by comparison.

As described above, the bearing inspection device 30 according to the present embodiment includes a sound sensor 32 that detects the sound generated from the bearing 20 to be inspected, a magnetic sensor 31 that detects the magnetism generated by the bearing 20, and the magnetic sensor 31. an analysis section 33 that frequency-analyzes the magnetic signal that is the detection result of the sound sensor 32; and an extraction section that extracts the sound signal of the rotation period of the bearing 20 from the sound signal that is the detection result of the sound sensor 32 using the result of the frequency analysis. 34. Therefore, the influence of surrounding environmental noise is reduced, and bearing inspection with high accuracy and a wide range of applications can be realized, which can be applied to bearings rotating at low speeds.

The bearing 20 to be inspected is preferably a rolling bearing with built-in rolling elements, and the extraction unit 34 searches for a peak of the period of the magnetic signal in the vicinity of the period estimated from the structure of the bearing 20. , the rotation period of the rolling elements and the rotation period of the inner ring can be determined and used as the rotation period of the bearing. Note that the rolling elements may be of any shape, such as balls or cylindrical rollers.

The bearing inspection device 30a also includes a plurality of sound sensors 32 corresponding to a plurality of bearings 20 rotating at the same period, and detects magnetism generated in any one of the plurality of bearings 20 with the magnetic sensor 31, and The extraction unit 34 extracts sound signals of the rotation period of each bearing 20 from the plurality of sound signals that are the detection results of the plurality of sound sensors 32 by sharing the results of the frequency analysis. The plurality of bearings are, for example, bearings provided on the same shaft. The determination unit 35a then compares the extraction results from the plurality of sound signals and determines the states of the plurality of bearings 20. According to this configuration, the states of the plurality of bearings 20 can be easily determined.

Moreover, if a sound signal whose sound pressure exceeds a predetermined threshold value among the extraction results by the extraction unit 34 is determined to be an abnormal sound, it is possible to easily and reliably determine whether the bearing 20 is abnormal. Further, it is also possible to distinguishably determine whether the rolling element is abnormal or the inner ring is abnormal.

In the above embodiment, it was explained that bearings can be inspected with high precision in an escalator that is a type of passenger conveyor. In addition, the present invention can be applied to bearings of any device, such as passenger conveyors that transport passengers horizontally, endless tracks (caterpillars) of construction machines, etc., and is particularly suitable for bearings operated at low speeds.

In addition, in the above embodiment, the explanation was given by exemplifying a sensor unit having a sound sensor and a magnetic sensor, but the sensor unit may be provided with a vibration sensor, a heat sensor, etc., and the outputs of these sensors may be further utilized. A configuration may be adopted in which the presence or absence of an abnormality is determined automatically.

Further, in the above embodiment, the case where a sensor unit having a magnetic sensor or a sound sensor is installed in contact with the retainer 21 was explained as an example, but the magnetic sensor or sound sensor does not necessarily need to be in contact with the retainer 21. There isn't. Magnetic sensors and sound sensors can also be used in a non-contact manner. In addition, if there are bearings with ample working space and bearings with limited working space, install a magnetic sensor on the bearing with sufficient working space, and install only sound sensors on the other bearings. It is also possible to implement the invention.

DESCRIPTION OF SYMBOLS 10... Escalator, 20... Bearing, 30... Bearing inspection device, 31... Magnetic sensor, 32... Sound sensor, 33... Analysis part, 34... Extraction part, 35... Judgment part, 36... Board, 37... Sensor unit

Claims (9)

A sound sensor that detects the sound generated from the bearing to be inspected;
a magnetic sensor that detects magnetism generated by the bearing;
an analysis unit that performs frequency analysis of a magnetic signal that is a detection result of the magnetic sensor;
an extraction unit that uses the result of the frequency analysis to extract a sound signal of the rotation period of the bearing from the sound signal that is the detection result of the sound sensor ;
A plurality of the sound sensors are provided corresponding to a plurality of bearings rotating at the same period,
The magnetic sensor detects magnetism generated in any of the plurality of bearings,
The bearing inspection device is characterized in that the extraction unit extracts a sound signal of a rotation period of each bearing from a plurality of sound signals that are detection results of a plurality of sound sensors by sharing the results of the frequency analysis. . The bearing inspection device according to claim 1, wherein the bearing is a rolling bearing having built-in rolling elements. The extraction unit searches for a peak of the period of the magnetic signal in the vicinity of the period estimated from the structure of the bearing, determines a rotation period of the rolling element and a rotation period of the inner ring, and sets the rotation period of the bearing as the rotation period. The bearing inspection device according to claim 2, characterized in that: The bearing inspection device according to claim 1, wherein the plurality of bearings are bearings provided on the same shaft. The bearing inspection device according to claim 1, further comprising a determination unit that compares extraction results from the plurality of sound signals and determines states of the plurality of bearings. The bearing inspection device according to claim 1, further comprising a determination unit that determines, among the extraction results by the extraction unit, a sound signal whose sound pressure exceeds a predetermined threshold value as an abnormal sound. The bearing is a rolling bearing with built-in rolling elements,
further comprising a determination unit that determines the presence or absence of an abnormality in the bearing from the extraction result by the extraction unit,
The bearing inspection device according to claim 1, wherein the determination unit determines an abnormality in the rolling element and an abnormality in the inner ring in a distinguishable manner. The bearing inspection device according to claim 1, wherein the bearing is used for a passenger conveyor. a sound detection step in which the bearing inspection device detects sound generated from the bearing to be inspected;
a magnetic detection step in which the bearing inspection device detects magnetism generated by the bearing;
an analysis step in which the bearing inspection device performs frequency analysis on the magnetic signal that is the detection result of the magnetic detection step;
The bearing inspection device includes an extraction step of extracting a sound signal of the rotation period of the bearing from the sound signal that is the detection result of the sound detection step, using the result of the frequency analysis,
The sound detection step detects sound for each of a plurality of bearings rotating at the same period,
The magnetic detection step detects magnetism generated in any of the plurality of bearings,
The bearing inspection is characterized in that the extraction step includes extracting sound signals of the rotational period of each bearing from a plurality of sound signals that are detection results for each of the plurality of bearings by sharing the results of the frequency analysis. Method.

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