CN109900475B

CN109900475B - Bearing inspection device

Info

Publication number: CN109900475B
Application number: CN201811013407.2A
Authority: CN
Inventors: 神鸟明彦; 沟口崇子; 小平法美; 大西友治; 松本俊昭; 马场理香
Original assignee: Hitachi Building Systems Co Ltd
Current assignee: Hitachi Building Systems Co Ltd
Priority date: 2017-12-08
Filing date: 2018-08-31
Publication date: 2020-12-22
Anticipated expiration: 2038-08-31
Also published as: CN109900475A; JP6975031B2; JP2019105457A

Abstract

The invention provides a bearing inspection device, which detects at least the magnetic force change generated by a bearing to reliably inspect the state of the bearing. The bearing inspection device includes a vibration sensor for detecting vibration of a bearing, a plurality of magnetic sensors for detecting magnetic force generated by the bearing, and a determiner for determining a state of the bearing based on an output signal of the vibration sensor and output signals of the respective magnetic sensors, wherein the determiner performs a 1 st determination as to whether a 1 st value obtained from the output signals of the vibration sensor is within a 1 st reference value range, performs a 2 nd determination as to whether a 2 nd value obtained from the output signals of the respective magnetic sensors is within a 2 nd reference value range, and determines at least whether the bearing is normal based on a result of the 1 st determination and a result of the 2 nd determination.

Description

Bearing inspection device

Technical Field

The present invention relates to a bearing inspection device for inspecting a bearing.

Background

A bearing that supports a rotating device so as to be freely rotatable is a device for smoothly rotating the rotating device. When the bearing fails, the operation of the rotating device may be stopped. Therefore, maintenance work is performed to prevent deterioration of the bearing. As a technique for determining the state of a bearing, for example, patent document 1 discloses that "a bearing state monitoring device 1 includes an AE sensor 10 attached to a bearing 3, a detection processing unit 30, an amplitude distribution calculating unit 32, a reference waveform generating unit 33, and a determining unit 22. The detection processing unit 30 performs detection processing on the signal from the AE sensor 10 to calculate a detected waveform. The amplitude distribution calculation unit 32 calculates an amplitude distribution from the detected waveform. The reference waveform generating unit 33 generates a reference waveform from the amplitude distribution. The determination unit 22 determines the state of the bearing 3 by comparing the amplitude distribution with the reference distribution. ".

However, even if the measurement data obtained from the AE sensor is used, the state of the bearing may not be reliably inspected.

Patent document 1: japanese patent laid-open publication No. 2011-252761

Disclosure of Invention

The invention aims to detect at least the magnetic force change generated by a bearing and reliably check the state of the bearing.

In order to solve the above problem, a bearing inspection device according to the present invention includes: a vibration sensor that detects vibration of the bearing; a plurality of magnetic sensors that detect magnetic force generated by the bearing; and a determiner that determines a state of the bearing based on an output signal of the vibration sensor and an output signal of the magnetic sensor, the determiner performing a 1 st determination of whether a 1 st value obtained from the output signal of the vibration sensor is within a range of a 1 st reference value, and performing a 2 nd determination of whether a 2 nd value obtained from the output signal of the magnetic sensor is within a range of a 2 nd reference value, and determining at least whether the bearing is normal based on a result of the 1 st determination and a result of the 2 nd determination. When it is necessary to make a more accurate determination, a temperature sensor for detecting the surface temperature of the bearing and an acoustic sensor for detecting the sound emitted from the bearing are disposed in addition to the magnetic sensor and the vibration sensor, and a reference value of an output signal from the temperature sensor and a reference value of an output signal from the acoustic sensor are set in the determiner, and the state of the bearing is determined by comprehensively determining information from the plurality of sensors by the determiner.

According to the present invention, at least a change in magnetic force generated by the bearing can be detected to reliably detect the state of the bearing.

Drawings

Fig. 1 is a circuit configuration diagram showing a bearing inspection apparatus according to an embodiment of the present invention.

Fig. 2 is a perspective view showing a state in which the sensor unit is attached to the housing portion of the bearing.

Fig. 3 is a diagram for explaining the internal configuration of the sensor unit, (a) is a front view, (b) is a perspective view, and (c) is a side view of the main part.

Fig. 4 is a plan view for explaining the relationship between the magnetic sensor and the magnet.

Fig. 5 is a diagram for explaining the magnetic sensor, (a) is a plan view showing a relationship between the magnetic sensor and the bearing, (b) is a structural diagram of a plurality of sensor units housing the magnetic sensor, (c) is a characteristic diagram (output waveform) of an output signal of each magnetic sensor housed in the plurality of sensor units, and (d) is a characteristic diagram (spectrum analysis result) showing a frequency analysis result of an output signal of each magnetic sensor housed in the plurality of sensor units.

Fig. 6 is a characteristic diagram (output waveform) of output signals of the magnetic sensor and the vibration sensor.

Fig. 7 is a diagram for explaining an analysis method by a computer, (a) is a waveform diagram showing a detection result of a peak detection time (maximum value indicated by P1 and minimum value indicated by P2) obtained by analyzing an output signal of a magnetic sensor, (b) is an explanatory diagram showing a detection result and a determination result of a time width (time width of the peak detection time) of each of P1 and P2, (c) is an explanatory diagram for explaining a relationship between a determination content and a threshold value according to a variation of the peak detection time width, and (d) is a diagram showing a display example of a determination result according to the detection result of the peak detection time width.

Fig. 8 is a diagram for explaining another analysis method performed by a computer, where (a) is a waveform diagram in which positions detected at the timings of rising and falling of the reference signal of (b) obtained by analyzing the output signal of the magnetic sensor are plotted, (b) is a waveform diagram showing the waveform of the reference signal, and (c) is a diagram in which the positions detected in (a) are plotted.

Fig. 9 is a diagram relating to the inspection of a bearing by a computer, where (a) is a flowchart for explaining a determination method by the computer, and (b) is a diagram showing a display example of a determination result by the computer.

Description of the symbols

10. 12 magnetic sensor, 14 vibration sensor, 16, 18 coil, 28 differential amplifier, 38 computer, 50 sensor unit, 52 bearing, 52a roller (rotor), 54 shell, 60, 62 side plate, 64 bottom plate, 72 magnet.

Detailed Description

Hereinafter, embodiments will be described with reference to the drawings.

(examples)

Fig. 1 is a circuit configuration diagram showing a bearing inspection apparatus according to an embodiment of the present invention. In fig. 1, the bearing inspection device includes

magnetic sensors

10 and 12, a vibration sensor 14,

coils

16 and 18, a temperature sensor 11, an acoustic sensor (microphone) 13, resistors 20 and 22, amplifiers 24 and 26, a differential amplifier 28,

amplifiers

30, 31, 32 and 33, an analog-to-digital converter (a/D converter) 34, a digital-to-analog converter (D/a converter) 36, and a computer 38. The computer 38 is constituted by a computer having, for example, a CPU (Central Processing Unit), a memory, an input/output interface, a display device (liquid crystal display), an input device (mouse, keyboard), and the like. The CPU executes various arithmetic processing and determination processing based on various programs stored in the memory, for example, a signal processing program, a frequency analysis program, a peak detection processing program, and the like, and displays the processing results on the display device.

The

magnetic sensors

10 and 12 are sensors that output changes and magnitudes of magnetic fields as electrical signals, and for example, AMR (Anisotropic magnetoresistive) sensors, TMR (Tunnel magnetoresistive) sensors, GMR (Giant magnetoresistive effect) sensors, and the like can be used. The vibration sensor 14 is a sensor that outputs the magnitude of vibration of the inspection object (bearing) as an electric signal, and for example, a piezoelectric element, an acceleration sensor, a velocity sensor, or the like can be used. The output signals of the

magnetic sensors

10 and 12 are output to a differential amplifier 28. A signal corresponding to the difference in the output signals of the

magnetic sensors

10, 12 is output from the differential amplifier 28, and the output signal is input to the analog-to-digital converter 34 via the amplifier 30. At this time, by obtaining the differential motion of the magnetic sensors 10 and 12 (this structure is called a gradiometer), it is possible to measure the difference of the measured magnetic fields, and to have an effect of eliminating an interfering magnetic field entering from a distance (for example, magnetic noise in a step portion). Further, the output signal of the vibration sensor 14 is input to the analog-digital converter 34 via the amplifier 32. Then, the output signal of the temperature sensor 11 is input to the analog-digital converter 34 via the amplifier 31. Further, an output signal of the sound sensor (microphone) 13 is input to the analog-digital converter 34 via the amplifier 33. The analog-digital converter 34 converts analog signals, which are output signals of the

amplifiers

30, 31, 32, and 33, into digital signals, respectively, and outputs the converted digital signals (digital information) to the computer 38. The computer 38 functions as a determiner that performs various arithmetic processing and determination processing based on the digital signals obtained from the output signals of the

magnetic sensors

10 and 12 and the digital signal obtained from the output signal of the vibration sensor 14. A method of canceling the offset magnetic field using feedback from the digital-to-analog converter 36 to each of the

magnetic sensors

10, 12 will also be described later.

Fig. 2 is a perspective view showing a state in which the sensor unit is mounted on the housing portion of the bearing. In fig. 2, a sensor unit 50 is detachably fixed to an outer peripheral surface of a housing 54 of a bearing 52 to be inspected (measurement target). The bearing 52 is formed of a rolling bearing including, for example, a cylindrical roller and a tapered roller, and is arranged to rotatably support one end of a rotating shaft (not shown) arranged at a lower portion of the escalator. The housing 54 is formed in a substantially cylindrical shape using, for example, a magnetic body (iron casting). The sensor unit 50 is formed into a substantially box-shaped case using a non-magnetic material (aluminum), and houses therein the

magnetic sensors

10 and 12, the vibration sensor 14, the temperature sensor 11, the acoustic sensor 13, the

coils

16 and 18, the resistors 20 and 22, the

amplifiers

24, 26, 31 and 33, and the differential amplifier 28. A connector 56 is fixed to a side surface of the sensor unit 50, and one end of a cable 58 is connected to the connector 56. The other end of the cable 58 is connected to a connector (not shown) connected to the input side of the

amplifiers

30, 32 and the output side (analog signal output side) of the digital-analog converter 36.

A sensor unit having the same function as the sensor unit 50 is detachably disposed on the outer peripheral surface of a housing (not shown) that rotatably supports a bearing (not shown) disposed at the other end of a rotating shaft (not shown) in the lower portion of the escalator. In this case, the circuit configuration of fig. 1 is a multiplex system except the computer 38, and the computer 38 processes electric signals from the

magnetic sensors

10 and 12, the vibration sensor 14, the temperature sensor 11, and the acoustic sensor 13 belonging to the sensor units 50.

Fig. 3 is a diagram for explaining the internal configuration of the sensor unit, (a) is a front view, (b) is a perspective view, and (c) is a side view of the main part. In fig. 3, the sensor unit 50 has an aluminum case including

side plates

60, 62 and a bottom plate 64, the connector 56 is fixed to a through hole 66 of the side plate 60, and the

substrates

68, 70, the vibration sensor 14, and the 4 magnets 72 are fixed to the bottom plate 64 serving as the bottom of the sensor unit 50. The

base plates

68, 70 are arranged substantially parallel to the

side plates

60, 62 and substantially perpendicular to the bottom plate 64. The connector 74 and the differential amplifier 28 are mounted on the substrate 68. The

magnetic sensors

10 and 12 are mounted on the substrate 70 so as to be separated from each other in the vertical direction (vertical direction), and the

coils

16 and 18, the resistors 20 and 22, and the

amplifiers

24, 26, 31 and 33 are mounted thereon (none of which is shown). The 4 magnets 72 are disposed at the four corners of the base plate 64. Each magnet 72 is formed in a substantially cylindrical shape, and a rubber cover 76 is attached to the bottom of each magnet 72.

The

magnetic sensors

10 and 12 are mounted on the substrate 70 so as to be spaced apart from each other, and the front end side (lower side) of the magnetic sensor 10 protrudes from an insertion hole (not shown) formed in the bottom plate 64. The

magnetic sensors

10 and 12 are disposed along the vertical direction (vertical direction) on the substrate 70, and detect the magnetic force in the vertical direction (Z-axis direction) generated by the bearing 52. At this time, since the differential amplifier 28 performs the difference processing on the output signals of the

magnetic sensors

10 and 12, even if the disturbing magnetic field acts on the respective

magnetic sensors

10 and 12 from the outside, the differential amplifier 28 outputs an electric signal from which the disturbing magnetic field from the outside is canceled.

As shown in fig. 3 c, the vibration sensor 14 is inserted between the pad 78 and the elastic body 80, and is supported by the pad 78 and the elastic body 80, the front end side (lower side) of the pad 78 protrudes from an insertion hole (not shown) formed in the bottom plate 64, and the elastic body 80 is fixed to the side plate 60 via a metal fitting 82. The vibration sensor 14 can detect the vibration of the bearing 52 via the housing 54 and the pad 78. At this time, in order to absorb the radial dimension of the housing 54, the front end side of the spacer 78 is formed in an arc shape in accordance with the shape (arc shape) of the outer peripheral surface of the housing 54, and the elastic body 80 movable in the vertical direction (up-down direction) is disposed on the upper side of the spacer 78 via the vibration sensor 14. In the case of a semiconductor sensor, the temperature sensor 11 is disposed at the tip of the pad 78. When the temperature sensor 11 is an infrared detection sensor, a hole is formed in the spacer 78 for measurement, or the temperature sensor is disposed at the bottom of the sensor unit 50 as in the case of the magnetic sensor 10. Two temperature sensors 11 are prepared, one of which measures the room temperature and the other of which can measure the temperature of the bearing 52 (the arrangement of the temperature sensors 11 is not shown). By measuring the difference temperature of these room temperatures and the temperature of the bearing 52, the temperature change of the bearing can be captured more accurately. Since the acoustic sensor 13 also detects the sound of the bearing 52, it is disposed at the tip of the pad 78 or at the bottom of the sensor unit 50 (the acoustic sensor 13 is not shown).

Since the 4 magnets 72 are fixed to the bottom plate 64, the sensor unit 50 is easily detachably fixed to the iron case 54. However, if the sensor unit 50 is fixed to the housing 54 via the magnets 72, the

magnetic sensors

10 and 12 detect the dc magnetic field of the magnets 72 and the residual magnetic field generated in the housing 54 (the residual magnetic field generated by fixing the magnets 72 to the housing 54), and the offset magnetic field increases due to the detected magnetic fields, and in this case, the detection outputs of the

magnetic sensors

10 and 12 may saturate, and the operation may become unstable.

Therefore, in the present embodiment, as shown in fig. 4, when 4 magnets 72 are arranged at four corners of the bottom plate 64, the magnetic sensor 10 is arranged at a substantially central portion of the bottom plate 64, that is, at a position (center point) substantially equidistant from the magnets 72 with a minimum leakage magnetic flux from the magnets 72. That is, the magnets 72 are disposed at positions substantially equidistant from the magnetic sensor 10, with the magnetic sensor 10 as the center. At this time, the magnets 72 are arranged such that the polarity (S-pole or N-pole) of the magnetic pole is different from the direction of the magnet 72 adjacent in the X direction or the Y direction. In order to project a part of each magnet 72 from the bottom plate 64, 4 through holes (not shown) are formed at positions substantially equidistant from the magnetic sensor 10 with the magnetic sensor 10 as the center, and each magnet 72 is inserted into each through hole to fix each magnet 72 to the bottom plate 64. The arrows in the figure indicate the direction of magnetic lines from the N-pole to the S-pole (the direction of the magnetic field).

By arranging four magnets 72 having opposite polarities around the magnetic sensor 10, the offset magnetic field detected by the magnetic sensor 10 can be suppressed to a small level (a level equal to or lower than an allowable value). In this case, the magnetic sensor 10 is arranged to operate with a leakage magnetic field of 1mT (tesla) or less, and the case including the bottom plate 64 is made of a non-magnetic material so that all the magnetic forces of the magnets 72 act on the metal case 54. Further, since the magnetic sensor 12 is farther from the housing 54 than the magnetic sensor 10, the level of the offset magnetic field detected by the magnetic sensor 12 is smaller than the detection level of the magnetic sensor 10. Therefore, the magnetic field generated by the bearing can be detected as a difference component. Further, a uniform disturbance magnetic field (magnetic field from a distance or the like) is simultaneously canceled.

When the

magnetic sensors

10 and 12 detect the offset magnetic field exceeding the allowable level, the computer 38 performs control to generate a magnetic field opposite to the offset magnetic field detected by the

magnetic sensors

10 and 12 from the

coils

16 and 18 to the

magnetic sensors

10 and 12 so as to cancel the offset magnetic field detected by the

magnetic sensors

10 and 12. At this time, the computer 38 acquires digital information (digital signal) relating to the offset magnetic field detected by the

magnetic sensors

10 and 12 via the analog-to-digital converter 34, executes arithmetic processing for canceling the offset magnetic field detected by the

magnetic sensors

10 and 12 based on the acquired digital information, and outputs a control signal for generating a magnetic field opposite to the offset magnetic field detected by the

magnetic sensors

10 and 12 based on the arithmetic result to the

coils

16 and 18 via the digital-to-analog converter 36, the amplifiers 24 and 26, and the resistors 20 and 22. As a result, a magnetic field opposite to the offset magnetic field detected by the

magnetic sensors

10 and 12 is generated from the

coils

16 and 18 to the

magnetic sensors

10 and 12. Therefore, the computer 38 can process the electric signals from the

magnetic sensors

10 and 12 in a stable state without being affected by the offset magnetic field detected by the

magnetic sensors

10 and 12. The digital-analog converter 36, the amplifiers 24 and 26, and the resistors 20 and 22 function as signal transmitters for transmitting control signals from the computer 38 to the

coils

16 and 18, respectively. The operation of eliminating the offset magnetic field as described above is performed immediately before the completion of the installation of the sensor unit 50 or at the beginning of the measurement, thereby enabling a stable operation. In the present embodiment, the configuration is such that the computer 38 is used, but a compact autonomous measuring device configuration may be adopted in which the microcomputer, the digital-analog converter 36, the amplifiers 24 and 26, and the resistors 20 and 22 are disposed inside the sensor unit 50, and a computer such as a personal computer is not used.

As another example of the method of fixing the 4 magnets 72 (described above, the fixing to the base plate 64 using an adhesive), when the 4 magnets 72 are arranged on the base plate 64, a cylindrical body having a screw portion inside is fixed in the vertical direction (up-down direction) around each through hole formed at the four corners of the base plate 64 on the upper side of the base plate 64, and one axial end of each of the 4 cylindrical bodies (made of iron) having a screw portion engaging with the screw portion of the cylindrical body on the outside is connected to each of the magnets 72, and the other end of each cylindrical body is inserted into each of the cylindrical bodies, and the screw portion of each cylindrical body is engaged with the screw portion of each of the cylindrical bodies, whereby each of the magnets 72 can be movably arranged in the vertical direction (up-down direction) in accordance with the rotation of each of the.

In fig. 5 a, the

magnetic sensors

10 and 12 are arranged in a direction (Z-axis direction) perpendicular to the axial direction of a rotating shaft (not shown) rotatably supported by the bearing 52 surrounded by the housing 54 and detect a magnetic field generated by the roller (rotating body) 52a in the bearing 52. As shown in fig. 5 (b), the plurality of sensor units 50 incorporating the

magnetic sensors

10 and 12 are disposed at both ends in the axial direction of a rotary shaft (not shown) disposed at the lower portion of the escalator. If the computer 38 is used to process the output signals (1 st output signal) obtained from the

magnetic sensors

10 and 12 incorporated in the sensor unit (1 st sensor unit) 50 located at the right end in the axial direction of the rotating shaft and the output signals (2 nd output signal) obtained from the

magnetic sensors

10 and 12 incorporated in the sensor unit (2 nd sensor unit) 50 located at the left end in the axial direction of the rotating shaft, respectively, as shown in fig. 5 c, a waveform 100 is displayed as a characteristic curve (output waveform) based on the 1 st output signal and a waveform 102 is displayed as a characteristic curve (output waveform) based on the 2 nd output signal on the display screen of the display device of the computer 38.

In addition, if the 1 st output signal and the 2 nd output signal are subjected to frequency analysis using the computer 38, as shown in (d) of fig. 5, a waveform 104 is displayed as an analysis result (spectrum analysis result) of the 1 st output signal and a waveform 106 is displayed as an analysis result (spectrum analysis result) of the 2 nd output signal on a display screen of a display device of the computer 38. At this time, the peak frequency of each

waveform

104, 106 is 1.2 Hz. The information on the

waveforms

100, 102, 104, and 106 is stored in the memory of the computer 38 as information during normal operation of the

magnetic sensors

10 and 12.

Fig. 6 is a characteristic diagram (output waveform) of output signals of the magnetic sensor and the vibration sensor. The computer 38 processes the output signals (1 st output signal) obtained from the

magnetic sensors

10 and 12 built in the sensor unit (1 st sensor unit) 50 and the output signals (2 nd output signal) obtained from the

magnetic sensors

10 and 12 built in the sensor unit (2 nd sensor unit) 50, respectively, and also processes the output signal (3 rd output signal) obtained from the vibration sensor 14 built in the sensor unit (1 st sensor unit) 50 and the output signal (4 th output signal) obtained from the vibration sensor 14 built in the sensor unit (2 nd sensor unit) 50, respectively, and displays the processing results on the display screen of the display device. For example, when a normal waveform is obtained, on the display screen of the display device of the computer 38, the waveform 108 is displayed as a characteristic curve based on the 1 st output signal, the waveform 110 is displayed as a characteristic curve based on the 2 nd output signal, the waveform 112 is displayed as a characteristic curve based on the 3 rd output signal, and the waveform 114 is displayed as a characteristic curve based on the 4 th output signal.

At this time, the computer 38 can determine whether or not the roller (bearing) 52a in the bearing 52 is rotating by processing the

waveforms

108 and 110, and can determine whether or not the bearing 52 is abnormally vibrated by processing the

waveforms

112 and 114. The waveform 116 is a waveform of vibration generated when the step of the escalator is retracted near the bearing 52. Although the signal waveforms of the acoustic sensor 13 and the temperature sensor 11 are not shown in fig. 5 and 6, the waveform of the acoustic sensor 13 is observed as a waveform similar to that of the vibration sensor 14 shown in fig. 6, and the temperature at the time of detection (1-point detection because there is no change in the detection time) is displayed in the temperature sensor 11.

Fig. 7 is a diagram for explaining an analysis method by a computer, (a) is a waveform diagram showing a detection result of a peak detection time (maximum value indicated by P1, minimum value indicated by P2) obtained by analyzing an output signal of a magnetic sensor, (b) is an explanatory diagram showing a detection result and a determination result of a time width (time width of a peak detection time) of each of P1 and P2, (c) is an explanatory diagram for explaining a relationship between a determination content and a threshold value according to a variation of the peak detection time width, and (d) is a diagram showing a display example of a determination result of a detection result according to the peak detection time width.

When the computer 38 processes the output signals (1 st output signal) obtained from the

magnetic sensors

10 and 12 incorporated in the sensor unit (1 st sensor unit) 50 and the output signals (2 nd output signal) obtained from the

magnetic sensors

10 and 12 incorporated in the sensor unit (2 nd sensor unit) 50, respectively, the computer performs a peak detection process or a frequency analysis process on each output signal, calculates the rotation speed (frequency) of the roller 52a in the bearing 52 from the processing result, and determines whether or not there is an abnormality in the bearing 52 from the calculation result (whether or not there is a speed deviation in the roller 52a or whether or not the roller 52a is movable).

As a result of the peak detection processing or the frequency analysis processing for the 1 st output signal, for example, the computer 38 displays the waveform of the signal 118 including the upper peak P1 and the lower peak P2 on the display screen of the display device as shown in fig. 7 (a), and displays the distribution state of the time width (peak detection time width) including the upper peak P1 and the lower peak P2 on the display screen of the display device as shown in fig. 7 (b). At this time, as shown in fig. 7 (C), the computer 38 refers to the threshold value 0.8 to 1.2Hz for the a determination (normal), the threshold value 0.4 to 0.8Hz and 1.2Hz to 1.6Hz for the B determination (attention), and the threshold value 0.4Hz or less and 1.6Hz or more for the C determination (abnormal), determines the processing result of the peak detection processing for the 1 st output signal, and displays the determination result on the display screen of the display device as shown in fig. 7 (d).

In this case, the time width (peak detection time width) between the upper peak P1 and the lower peak P2 is within the range of the threshold value for a determination, and thus is determined as a determination. Further, from the analysis result of the signal 118 including the upper peak P1 and the lower peak P2, it is determined that the rotational speed of the roller 52a is 1Hz, and it is shown that the rotational speed of the roller 52a is 1Hz, and there is no speed deviation in the roller 52 a.

Fig. 8 is a diagram for explaining another analysis method performed by a computer, where (a) is a waveform diagram depicting positions detected at the rising and falling times of a reference signal of (b) obtained by analyzing an output signal of a magnetic sensor, (b) is a waveform diagram showing a waveform of the reference signal, and (c) is a diagram depicting the positions detected in (a).

When the output signals (1 st output signal) obtained from the

magnetic sensors

10 and 12 built in the sensor unit (2 nd sensor unit) 50 are processed separately, for example, peak detection processing or frequency analysis processing is performed on the 1 st output signal, and when the signal 120 shown in fig. 8 (a) is obtained in this processing, this signal 120 is compared with the reference signal (signal obtained by knowing the bearing frequency) 120 shown in fig. 8 (b), and the comparison results are output as peaks P11 to P15 and peaks P21 to P25 as shown in fig. 8 (c).

At this time, the computer 38 detects values in synchronization with the rise of the reference signal 122 as peak values P11 to P15 and values in synchronization with the fall of the reference signal 122 as peak values P21 to P25 in the signal 120. The computer 38 can determine whether or not the bearing 52 is abnormal based on whether or not the distribution state of the peaks P11 to P15 and P21 to P25 is within a normal range (within a threshold value range).

Fig. 9 is a diagram relating to the inspection of a bearing by a computer, where (a) is a flowchart for explaining a determination method by the computer, and (b) is a diagram showing an example of the display of the determination result by the computer. Although not described here, the determination by the temperature sensor 11 and the sound sensor 13 may be made in detail by making a reference for each sensor. For example, when the temperature sensor 11 reaches a certain temperature or higher, it can be used for determining that the bearing is in the locked state. The sound sensor 13 can be used to determine an abnormal value that cannot be recorded using the vibration sensor 14, thereby improving the accuracy of the determination 1.

magnetic sensors

10, 12 built in the sensor unit (1 st sensor unit) 50, the output signals (2 nd output signal) obtained from the

magnetic sensors

10, 12 built in the sensor unit (2 nd sensor unit) 50, the output signal (3 rd output signal) obtained from the vibration sensor 14 built in the sensor unit (1 st sensor unit) 50, and the output signal (4 th output signal) obtained from the vibration sensor 14 built in the sensor unit (2 nd sensor unit) 50, respectively, for example, the frequency analysis processing is performed on the 3 rd output signal, and it is determined whether or not the amplitude range of the reference frequency band of the output signal of the vibration sensor 14 is within the reference (S1), the determination result (normal or abnormal) is output, and the determination result (result of determination 1) is displayed on the display screen of the display device.

Next, the computer 38 executes, for example, peak detection processing or frequency analysis processing for the 1 st output signal, and determines whether the bearing (the roller 52a) is within a reference frequency range (whether the rotation speed of the roller 52a is within the reference frequency range) or whether the variation in the peak detection time width is within the reference range (whether the peak detection time width of the peak position overlapping the output signals of the

magnetic sensors

10, 12 is within the reference range) (S2), outputs the determination result (normal or abnormal) and displays the determination result (the result of determination 2) on the display screen of the display device, and ends the processing in this routine.

When the determination result of step S1 is normal (o) and the determination result of step S2 is normal (o), the bearing 52 is "normal", the computer 38 sets the determination result combining the processing of steps S1, S2 to "a (a determination)" and displays these pieces of information on the display screen of the display device. When the determination result of step S1 is normal (o) and the determination result of step S2 is abnormal (x), "the bearing 52 is in a state after one wear (the roller 52a inside the bearing 52 is in a state of abnormal motion)", the computer 38 sets the determination result combining the processes of steps S1, S2 to "B (B determination)", and displays these pieces of information on the display screen of the display device. When the determination result of step S1 is abnormal (x) and the determination result of step S2 is normal (o), "the bearing 52 is in a state of being barely rotated (the bearing 52 is in a state of being abnormally vibrated)", the computer 38 sets the determination result combining the processes of steps S1, S2 to "B (B determination)", and displays these pieces of information on the display screen of the display device. When the determination result of step S1 is abnormal (x), and the determination result of step S2 is abnormal (x), "the bearing 52 is in the locked state", the computer 38 sets the determination result combining the processes of steps S1, S2 to "C (C determination)", and displays these pieces of information on the display screen of the display device.

However, the "state" shown here is an example, and may be described as a "state" expressed by using a different expression.

According to the present embodiment, it is possible to detect at least a change in the magnetic force generated by the bearing 52 to reliably check the state of the bearing 52. That is, in the case other than the combination in which the result of step S1 is normal and the result of step S2 is normal, it can be determined that the state of the bearing 52 is not normal. In addition, when the result of step S1 is normal and the result of step S2 is abnormal, it can be determined that the bearing 52 is in a state after being worn once, when the result of step S1 is abnormal and the result of step S2 is normal, it can be determined that the bearing 52 is in a state of being rotated by force, and when the result of step S1 is abnormal and the result of step S2 is abnormal, it can be determined that the bearing 52 is in a locked state.

The present invention is not limited to the above embodiments, and various modifications may be made. For example, the above-described embodiments are described in detail to facilitate understanding of the present invention, and are not limited to having all the configurations described. In addition, other configurations can be added, deleted, and replaced for a part of the configurations of the embodiments.

The above-described structures, functions, and the like may be implemented in part or all of hardware, for example, by designing using an integrated circuit. In addition, the above-described respective structures, functions, and the like can be realized by software by interpreting and executing programs that realize the respective functions by a processor. Information such as programs, tables, and files for realizing the respective functions can be recorded in a recording device such as a memory, a hard disk, or an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or a DVD.

Claims

1. A bearing inspection device is characterized by comprising:

a vibration sensor that detects vibration of the bearing;

a plurality of magnetic sensors that detect magnetic force generated by the bearing; and

a determiner for determining a state of the bearing based on an output signal of the vibration sensor and an output signal of the magnetic sensor,

the determiner performs a 1 st determination as to whether a 1 st value derived from the output signal of the vibration sensor is within a range of a 1 st reference value, and performs a 2 nd determination as to whether a 2 nd value derived from the output signal of the magnetic sensor is within a range of a 2 nd reference value, and determines at least whether the bearing is normal based on a result of the 1 st determination and a result of the 2 nd determination,

the bearing inspection device has a sensor unit, which is a non-magnetic body and is formed in a box shape, for housing the vibration sensor and the magnetic sensor,

the sensor unit has a plurality of magnets disposed at a bottom thereof, and is detachably fixed to an outer peripheral surface of a housing of an annular magnetic body configured to surround the bearing via the plurality of magnets,

the magnetic sensor is located at a center portion of the sensor unit and is disposed in a direction orthogonal to an axial direction of a rotating shaft rotatably supported by the bearing,

the plurality of magnets is comprised of at least 4 magnets,

the magnets are disposed at positions distributed at equal distances from one of the magnetic sensors, with the one of the magnetic sensors disposed on the bottom side of the sensor unit being the center, and in a direction opposite to the polarity of the adjacent magnet.

2. The bearing inspection apparatus of claim 1,

the determiner determines that the state of the bearing is not normal in a case where a result of the 1 st determination is normal and the result of the 2 nd determination is not a combination of normal.

3. The bearing inspection apparatus of claim 1,

in the case where the result of the 1 st determination is normal and the result of the 2 nd determination is abnormal, the determiner determines that the roller inside the bearing is in an abnormal-motion state.

4. The bearing inspection apparatus of claim 1,

in a case where a result of the 1 st determination is abnormal and a result of the 2 nd determination is normal, the determiner determines that the bearing is in a state of abnormal vibration.

5. The bearing inspection apparatus of claim 1,

in the case where the result of the 1 st determination is abnormal, and the result of the 2 nd determination is abnormal, the determiner determines that the bearing is in the locked state.

6. The bearing inspection apparatus of claim 1,

the determiner calculates an amplitude range of a reference frequency band as the 1 st value from the output signal of the vibration sensor, and calculates a value of a peak detection time width of a rotation speed of a roller belonging to the bearing or a peak position superimposed on the output signal of the magnetic sensor as the 2 nd value from the output signal of the magnetic sensor.

7. The bearing inspection apparatus according to any one of claims 1 to 6,

the bearing inspection apparatus has a differential amplifier between the magnetic sensors and the determiner, generates an electric signal corresponding to a difference between an output signal of one of the magnetic sensors and an output signal of the other magnetic sensor, and outputs the generated electric signal to the determiner.

8. The bearing inspection apparatus according to any one of claims 1 to 6,

the bearing inspection device comprises:

a 1 st coil that forms a magnetic field around one of the magnetic sensors;

a 2 nd coil that forms a magnetic field around another one of the magnetic sensors;

a 1 st signal transmitter connecting the 1 st coil and the determiner; and

a 2 nd signal transmitter connecting the 2 nd coil and the determiner,

the determiner generates a 1 st control signal for canceling a 1 st offset magnetic field caused by detection of the one magnetic sensor, transmits the generated 1 st control signal to the 1 st coil via the 1 st signal transmitter, and causes the 1 st coil to generate a 1 st magnetic field for canceling the 1 st offset magnetic field,

the determiner generates a 2 nd control signal for canceling a 2 nd offset magnetic field caused by detection of the other magnetic sensor, transmits the generated 2 nd control signal to the 2 nd coil via the 2 nd signal transmitter, and causes the 2 nd coil to generate a 2 nd magnetic field for canceling the 2 nd offset magnetic field.

9. A bearing inspection device is characterized by comprising:

a vibration sensor that detects vibration of the bearing;

a plurality of magnetic sensors that detect magnetic force generated by the bearing;

a plurality of sound sensors that detect sound emitted from the bearings;

a plurality of temperature sensors that detect heat emitted from the bearings; and

a determiner that determines a state of the bearing based on an output signal of the vibration sensor, an output signal of the magnetic sensor, an output signal of the acoustic sensor, and an output signal of the temperature sensor,

the determiner performs a 1 st determination of whether a 1 st value obtained from the output signal of the vibration sensor is within a range of a 1 st reference value, and performs a 2 nd determination of whether a 2 nd value obtained from the output signal of the magnetic sensor is within a range of a 2 nd reference value, performs a 3 rd determination of whether a 3 rd value obtained from the acoustic sensor is within a range of a 3 rd reference value, performs a 4 th determination of whether a 4 th value obtained from the temperature sensor is within a range of a 4 th reference value, and determines at least whether the bearing is normal based on a result of the 1 st determination and results of the 2 nd determination, the 3 rd determination, and the 4 th determination,

the bearing inspection device has a sensor unit which is a non-magnetic body and is formed in a box shape for housing the vibration sensor, the magnetic sensor, the sound sensor, and the temperature sensor,

the plurality of magnets is comprised of at least 4 magnets,

10. The bearing inspection apparatus of claim 9,

and configuring 2 temperature sensors, calculating a difference value of the outputs of the 2 temperature sensors, and outputting a temperature value of the difference value.