JP7150450B2 - Acceleration detection device and bearing device provided with the same - Google Patents

Description

The present invention relates to an acceleration detection device and a bearing device having the same.

As a method for improving the detection accuracy of the acceleration sensor, in International Publication No. WO 2015/145489, two acceleration sensors are arranged with the detection directions opposite to each other on one detection substrate, and a differential signal is obtained from these. proposed a method to solve the structural imbalance problem.

As a similar method, in Japanese Patent No. 3129120, two sets of piezoelectric elements or the like are installed so that their expansion and contraction directions are opposite to each other, and differential signals output from these are detected. Therefore, a method of canceling deformation due to temperature change has been proposed.

WO2015/145489 Japanese Patent No. 3129120

When the control unit on the input side receives a signal output from the sensor housing via a cable or wirelessly, it is difficult for the control unit to distinguish between the signal and the noise if disturbance noise is superimposed on the transmission path. Therefore, a differential signal is transmitted from the pair of sensors to the control unit.

Conventionally, when outputting a differential signal, a pair of facing sensors and piezoelectric elements have the same physical characteristics.

However, in order to increase the S/N ratio of the acceleration sensor, it is desirable to use a narrow band sensor close to the upper limit of the acceleration value generated from the object to be measured. However, the accelerometer often goes over the range due to unexpected disturbances, etc., and there are many cases where the use of a wideband sensor is unavoidable for safety reasons. In addition, acceleration sensors such as piezoelectric elements have a high failure rate due to external disturbances such as shock loads and sudden inflow currents, so it is desired to ensure redundancy.

The present invention is intended to solve such problems, and its object is to accurately detect acceleration signals suitable for use in environments with a lot of disturbance noise such as railway vehicles, construction machines, and agricultural machines. It is another object of the present invention to provide an acceleration detection device with high redundancy.

An acceleration detection device according to the present disclosure includes a first acceleration sensor and a second acceleration sensor having a measurement frequency band or an acceleration detection range different from that of the first acceleration sensor. The first acceleration sensor and the second acceleration sensor are arranged such that the positive directions of the acceleration detection axes are opposite to each other.

Preferably, the acceleration detection device further includes a level adjustment unit that receives the output of at least one of the first acceleration sensor and the second acceleration sensor, and adjusts the levels of the output signals of the first acceleration sensor and the second acceleration sensor to match. Prepare.

More preferably, it further comprises a differential processing section that performs differential processing on the outputs of the first acceleration sensor and the second acceleration sensor after passing through the level adjustment section.

Preferably, the acceleration detection device uses either one of the first processing using the output of the first acceleration sensor and the output of the second acceleration sensor, and the output of the first acceleration sensor and the output of the second acceleration sensor. and a detection processor configured to perform a second process. The detection processing unit executes the first process when both the output of the first acceleration sensor and the output of the second acceleration sensor are normal, and detects which of the output of the first acceleration sensor and the output of the second acceleration sensor. If one of them is normal and the other is not normal, the normal output of the acceleration sensor is used to execute the second process.

Preferably, the acceleration detection device includes a differential output section that outputs a differential signal between the output of the first acceleration sensor and the output of the second acceleration sensor, the forward rotation signal of the output of the first acceleration sensor, and the output of the second acceleration sensor. and a signal output unit for outputting an inverted signal of .

Preferably, the acceleration detection device receives the output of the first acceleration sensor and the output of the second acceleration sensor, receives a differential signal between the output of the first acceleration sensor and the output of the second acceleration sensor, and the output of the first acceleration sensor. and an input processing unit that outputs a normal signal of the second acceleration sensor and an inverted signal of the second acceleration sensor.

INDUSTRIAL APPLICABILITY According to the acceleration detection device of the present invention, an acceleration signal can be accurately detected even in an environment with a lot of disturbance noise such as railroad vehicles, construction machinery, agricultural machinery, etc., and redundancy against failure can be enhanced.

1 is a circuit diagram showing the configuration of an acceleration detection device according to Embodiment 1; FIG. FIG. 4 is a waveform diagram for explaining the operation of the level adjusting section; 2 is a circuit diagram showing the configuration of an acceleration detection device according to Embodiment 2; FIG. 4 is a circuit diagram showing a configuration of a signal processing unit in FIG. 3; FIG. 4 is a flowchart for explaining a case where a control unit performs software processing; 1 is a block diagram showing the configuration of a bearing device including an acceleration detection device and a state monitoring device; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings below, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated.

[Embodiment 1]
FIG. 1 is a circuit diagram showing the configuration of an acceleration detection device according to Embodiment 1. FIG. Referring to FIG. 1, acceleration detection device 1 includes a first acceleration sensor SA and a second acceleration sensor SB. The second acceleration sensor SB differs from the first acceleration sensor SA in a measurement frequency band or an acceleration detection range. For example, if the acceleration detection range of the first acceleration sensor SA is -m1 to +m1 (G) and the acceleration detection range of the second acceleration sensor SB is -m2 to +m2 (G), then m1>m2. Therefore, the detection range of the first acceleration sensor SA is wider than that of the second acceleration sensor SB, and the second acceleration sensor SB tends to overrange when a strong excitation force is applied. Instead, the sensitivity of the second acceleration sensor SB is higher than the sensitivity of the first acceleration sensor SA. Therefore, when the same vibration is applied, the second acceleration sensor SB outputs a signal with a larger amplitude than the first acceleration sensor SA.

The first acceleration sensor SA and the second acceleration sensor SB are arranged such that the positive directions of the acceleration detection axes are opposite to each other. The positive direction of the first acceleration sensor SA is the same as the direction indicated by the arrow X, and the positive direction of the second acceleration sensor SB is the opposite direction.

The acceleration detection device 1 receives the output of at least one of the first acceleration sensor SA and the second acceleration sensor SB, and adjusts the levels of the output signals of the first acceleration sensor SA and the second acceleration sensor SB so that they are level. 20. The level adjustment unit 20 may include level adjustment processing units 21 and 22 corresponding to the first acceleration sensor SA and the second acceleration sensor SB, respectively, as shown in FIG. It may include only the level adjustment processing section.

For example, if the amplitude of the signal output by the second acceleration sensor SB is twice the amplitude of the signal output by the first acceleration sensor SA, the level adjustment unit 20 directly outputs the output of the first acceleration sensor SA. At the same time, processing is performed to attenuate the amplitude of the signal output from the second acceleration sensor SB to 1/2, and the levels of the two signals are aligned.

The acceleration detection device 1 further includes a differential processing section 24 that performs differential processing on the outputs of the first acceleration sensor SA and the second acceleration sensor SB after passing through the level adjustment section 20 .

The acceleration detection device 1 further includes a signal output unit 10 that outputs a normal signal output from the first acceleration sensor SA and an inverted signal output from the second acceleration sensor SB. As described above, the acceleration detection device 1 according to the first embodiment makes the output signals OUTA to OUTC available, so that the user can monitor the acceleration using the easy-to-use outputs as needed.

FIG. 2 is a waveform diagram for explaining the operation of the level adjusting section. 1 and 2, waveform A1 is the waveform output by first acceleration sensor SA, and waveform B1 is the waveform output by second acceleration sensor SB. The basic waveforms of the vibration are the waveform A1 and the waveform B1, which are in opposite phases. Waveform B1 has twice the amplitude of waveform A1. In the transmission path, noise of the same phase and the same magnitude is superimposed on the signal.

Waveforms A2 and B2 are waveforms after passing through the level adjustment section 20 . The level adjusting section 20 passes the waveform A1 as it is and halves the amplitude of the waveform B1. At this time, the magnitude of the noise in the waveform B2 becomes half of the original.

Signal OUTC is the output of differential processor 24 in FIG. Subtracting waveform B2 from waveform A2 doubles the amplitude of the fundamental signal and halves the noise relative to waveform A2. Therefore, the S/N ratio of the signal is improved.

The user appropriately selects one of the signal OUTA, which is the output of the first acceleration sensor SA as it is, the signal OUTB, which is the inverted output of the output of the second acceleration sensor SB, and the signal OUTC with reduced noise. can be used.

The user can use, for example, the signal OUTB with high sensitivity when the vibration is minute, and the signal OUTA with a wide range when the vibration is large. If the signal OUTB is superimposed with noise and has a low S/N ratio, the user can use the signal OUTC.

Also, even if one of the first acceleration sensor SA and the second acceleration sensor SB fails, the signal of the other can be used.

As described above, according to the acceleration detection device of Embodiment 1, the acceleration signal can be accurately detected even in an environment with a lot of disturbance noise such as railway vehicles, construction machinery, and agricultural machinery. Furthermore, redundancy against failure can be enhanced.

[Embodiment 2]
The acceleration detection device 1 of Embodiment 1 uses two acceleration sensors with different sensitivity bands or maximum detectable accelerations. Then, the two acceleration sensors are attached so that the directions of the detection axes are opposite to each other. From the first acceleration sensor SA installed in one positive direction, an amplitude signal with a positive sign is output in accordance with the vibration direction. The second acceleration sensor SB, which is installed in the opposite direction, outputs an amplitude signal having a sign opposite to the vibration direction.

In the second embodiment, by inputting the signal outputs from the two acceleration sensors into the control unit, flexible processing, which will be described later, can be performed in the control unit.

FIG. 3 is a circuit diagram showing the configuration of the acceleration detection device according to the second embodiment. Referring to FIG. 3, acceleration detection device 2 includes a first acceleration sensor SA, a second acceleration sensor SB, and detection processing section 100 .

As in the first embodiment, the first acceleration sensor SA and the second acceleration sensor SB are installed in opposite directions and have different characteristics.

The detection processing unit 100 performs either a first process using the output of the first acceleration sensor SA and the output of the second acceleration sensor SB, or one of the output of the first acceleration sensor SA and the output of the second acceleration sensor SB. and a second process using.

When both the output of the first acceleration sensor SA and the output of the second acceleration sensor SB are normal, the detection processing unit 100 executes the first process to detect the output of the first acceleration sensor SA and the output of the second acceleration sensor SB. If one of the outputs of the SB is normal and the other is not normal, the normal output of the acceleration sensor is used to execute the second process.

The detection processing section 100 includes an input processing section 130 and a signal processing section 105 . The input processing unit 130 generates a differential signal between the output of the first acceleration sensor SA and the output of the second acceleration sensor SB, a normal signal of the output of the first acceleration sensor SA, and an inverted signal of the output of the second acceleration sensor SB. Executes a process that outputs and The input processing unit 130 includes a signal output unit 110 that outputs a normal signal of the output of the first acceleration sensor SA and a reverse signal of the output of the second acceleration sensor SB; 2, a level adjusting section 120 for receiving the output of the acceleration sensor SB and performing level adjustment, and a differential processing section 104 . The signal output unit 110 includes an inverting circuit 101 that outputs an inverted signal of the output of the second acceleration sensor SB. The level adjustment unit 120 includes level adjustment processing units 102 and 103 that adjust the levels of the outputs of the first acceleration sensor SA and the second acceleration sensor SB, respectively. The differential processing unit 104 outputs a differential signal between the output of the first acceleration sensor SA and the output of the second acceleration sensor SB, the levels of which are adjusted by the level adjustment processing units 102 and 103 .

The signal processing unit 105 receives the non-inverted signal of the output of the first acceleration sensor SA, the output of the inverting circuit 101, and the output of the differential processing unit 104, and outputs a signal OUT.

FIG. 4 is a circuit diagram showing the configuration of the signal processing section of FIG. Referring to FIG. 4 , signal processing section 105 includes a signal determining section 106 and a signal selecting section 107 .

The signal determination unit 106 receives the normal rotation signal of the output of the first acceleration sensor SA and the output of the inverting circuit 101, and determines whether or not each signal is normal. For example, when there is an abnormality such as disconnection, the signal cannot be detected, so that it can be determined that there is an abnormality. Also, if it is detected that the level of each signal exceeds a predetermined threshold value, it can be determined that the magnitude of the vibration being monitored is large and is over range.

If one of the normal rotation signal of the output of the first acceleration sensor SA and the output signal of the inverting circuit 101 is normal and the other is abnormal, the signal determination unit 106 outputs a normal signal to the signal selection unit 107. let you choose.

Further, when the vibration to be monitored is minute and it is desired to increase the sensitivity, the signal determination unit 106 changes the output signal of the inverting circuit 101 (inverted signal of the input B) so that the second acceleration sensor SB detects the vibration. is selected by the signal selection unit 107 .

Further, when the vibration to be monitored exceeds the observation range of the second acceleration sensor SB, the signal determination section 106 causes the signal selection section 107 to select the forward rotation signal (input A) of the first acceleration sensor SA.

When the S/N ratio between the non-inverted signal of the output of the first acceleration sensor SA and the output signal of the inversion circuit 101 is bad, the signal determination unit 106 causes the signal selection unit 107 to select the output of the differential processing unit 104. .

In this way, the signals are selected by the signal determination unit 106 and the signal selection unit 107, so that the output of a normal sensor can be used in the event of a failure, and the S/N ratio is reduced by the differential signal in an environment with a lot of noise. can get an improved signal.

Note that FIG. 4 shows an example in which the detection processing unit 100 is implemented by a hardware circuit, but the processing in the control unit may be implemented by either a method using a hardware circuit or a method using software.

FIG. 5 is a flowchart for explaining a case where the control unit performs software processing. Before this processing is executed, processing is performed in the input processing unit 130 so that the output range of the acceleration sensor in the forward direction and the output range of the maximum acceleration match the output range of the acceleration sensor in the other reverse direction. It is running.

The process of this flow chart is called from the main routine of the vibration monitoring process and is repeatedly executed to select a sensor as appropriate.

First, in step S1, the detection processing unit 100 determines whether or not there is a signal from the second acceleration sensor SB. If there is no signal from the second acceleration sensor SB (NO at S1), the process proceeds to step S2, and if there is a signal from the second acceleration sensor SB (YES at S1), the process proceeds to step S3.

At step S2, the detection processing unit 100 determines whether or not there is a signal from the first acceleration sensor SA. If there is no signal from the first acceleration sensor SA (NO in S2), the process proceeds to step S6, and the detection processing unit 100 determines that there is a sensor failure. On the other hand, if there is a signal from the first acceleration sensor SA (YES in S2), the process proceeds to step S7.

Further, when the process proceeds to step S3, the detection processing unit 100 determines whether or not there is a signal from the first acceleration sensor SA. If there is no signal from the first acceleration sensor SA (NO in S3), the process proceeds to step S9. On the other hand, if there is a signal from the first acceleration sensor SA (YES in S3), the process proceeds to step S4.

In step S4, the detection processing unit 100 determines whether the output of the second acceleration sensor SB is greater than a predetermined threshold value, thereby determining whether the second acceleration sensor SB is over range. do.

If the second acceleration sensor SB is over range (YES in S4), the process proceeds to step S7. On the other hand, if the second acceleration sensor SB is not over range (NO in S4), the process proceeds to step S5.

In step S5, it is determined whether or not the S/N ratio of the output signal of the second acceleration sensor SB is lower than the determination value. If the S/N ratio of the output signal of the second acceleration sensor SB is lower than the determination value (YES in S5), the process proceeds to step S8. On the other hand, if the S/N ratio of the output signal of the second acceleration sensor SB is greater than or equal to the judgment value (NO in S5), the process proceeds to step S9.

Sensor selection is executed by the above processing. At step S7, the first acceleration sensor SA is selected. Differential output is selected in step S8. In step S9, the second acceleration sensor SB is selected.

After a failure is determined in step S6 or a signal is selected in steps S7, S8 and S9, the process returns to the main routine in step S10.

As described above, the acceleration detection devices described in Embodiments 1 and 2 perform level adjustment and differential processing of the outputs of the two acceleration sensors, so that noise superimposed on paths such as the sensor section and cables is detected. can be reduced, and highly accurate acceleration detection becomes possible.

Also, if the sensitivity band of the acceleration sensor on the reverse direction side is narrower than that of the sensor on the forward direction side, or if the maximum detectable acceleration is smaller than that of the sensor on the forward direction side, when the vibration exceeding the allowable range in the reverse direction is detected, the acceleration in the forward direction is detected. A sensor can detect a signal.

Also, even if one of the acceleration sensors fails, the remaining acceleration sensors can still detect vibrations, ensuring redundancy.

[Application example]
The acceleration detection devices described in the first and second embodiments can be used to detect various accelerations. As an example, a bearing device in which an acceleration detection device is attached to a bearing will be described.

FIG. 6 is a block diagram showing the configuration of the bearing device including the acceleration detection device and the condition monitoring device. Referring to FIG. 6, condition monitoring device 300 receives a signal from acceleration detection device 2 incorporated in bearing device 200, monitors the condition of bearing device 200, and detects an abnormality. The bearing device 200 is used, for example, in rotating equipment installed in factories, power plants, and the like. Bearing device 200 includes rolling bearing 212 and acceleration detection device 2 described in the second embodiment. The acceleration detection device 1 of the first embodiment may be incorporated in the bearing device 200 instead of the acceleration detection device 2 of the second embodiment. In this case, among the three outputs of the acceleration detection device 1, the output that can obtain the waveform that can best observe the vibration is used.

Rolling bearing 212 includes an inner ring 216 fitted to rotating shaft 219, an outer ring 214 fixed to bearing device 200, and a plurality of rolling elements 218 arranged between the inner ring and the outer ring.

State monitoring device 300 includes an amplifier 310 , a filter 320 , an A/D converter 330 , a data acquisition section 340 , a storage device 350 , a data calculation section 360 and a display section 370 .

A voltage waveform (hereinafter referred to as an oscillating voltage waveform) output by the acceleration detection device 2 is amplified by an amplifier 310, and is subjected to a band-pass filtering process in which signals in bands unnecessary for analysis are removed by a filter 320 and only necessary bands are passed. processing is performed. A/D converter 330 receives the output signal of amplifier 310 . The data acquisition section 340 receives the digital signal from the A/D converter 330 and records the measurement data in the storage device 350 . The data calculation unit 360 reads measured data from the storage device 350 and performs FFT analysis and the like to monitor the state of the bearing device 200 .

The data calculation unit 360 determines whether or not there is an abnormality in the bearing device 200 based on the monitoring results. When determining whether or not there is an abnormality, the data calculation unit 360 causes the display unit 370 to display the determination result.

As described above, the acceleration detection device of the present embodiment can be incorporated in a bearing device and suitably used for monitoring the condition of the bearing.

Further, in the above-described embodiment, the output amplitude is attenuated for different maximum detected accelerations, but the amplitude may be amplified to match the level. Moreover, as a characteristic adjustment when the frequency bands are different, the pass band may be limited by a filter such as a low-pass filter for a sensor that outputs a signal with a high frequency.

The embodiments disclosed this time should be considered as examples and not restrictive in all respects. The scope of the present invention is indicated by the scope of the claims rather than the description of the above-described embodiments, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

1, 2 acceleration detection device 10, 110 signal output unit 20, 120 level adjustment unit 21, 22, 102, 103 level adjustment processing unit 24, 104 differential processing unit 100 detection processing unit 11, 101 inversion Circuit 105 Signal processing unit 106 Signal determination unit 107 Signal selection unit 130 Input processing unit 200 Bearing device 212 Bearing 214 Outer ring 216 Inner ring 218 Rolling element 219 Rotating shaft 300 Condition monitoring device 310 Amplifier , 320 filter, 330 A/D converter, 340 data acquisition unit, 350 storage device, 360 data calculation unit, 370 display unit, SA first acceleration sensor, SB second acceleration sensor.

Claims (6)

a first acceleration sensor;
A second acceleration sensor having a measurement frequency band or an acceleration detection range different from that of the first acceleration sensor,
the first acceleration sensor and the second acceleration sensor are arranged such that positive directions of acceleration detection axes are opposite to each other;
Acceleration, further comprising a level adjustment unit that receives the output of at least one of the first acceleration sensor and the second acceleration sensor, and adjusts the levels of the output signals of the first acceleration sensor and the second acceleration sensor so that they are aligned. detection device. 2. The acceleration detection device according to claim 1 , further comprising a differential processing section that performs differential processing on the outputs of said first acceleration sensor and said second acceleration sensor after passing through said level adjustment section. a first acceleration sensor;
A second acceleration sensor having a measurement frequency band or an acceleration detection range different from that of the first acceleration sensor,
the first acceleration sensor and the second acceleration sensor are arranged such that positive directions of acceleration detection axes are opposite to each other;
A first process using the output of the first acceleration sensor and the output of the second acceleration sensor, and a second process using either one of the output of the first acceleration sensor and the output of the second acceleration sensor. further comprising a detection processor configured to perform
The detection processing unit executes the first process when both the output of the first acceleration sensor and the output of the second acceleration sensor are normal, and the output of the first acceleration sensor and the output of the second acceleration sensor 1. An acceleration detecting device, wherein, when one of the outputs of an acceleration sensor is normal and the other is not normal, the normal output of the acceleration sensor is used to execute the second process. a first acceleration sensor;
A second acceleration sensor having a measurement frequency band or an acceleration detection range different from that of the first acceleration sensor,
the first acceleration sensor and the second acceleration sensor are arranged such that positive directions of acceleration detection axes are opposite to each other;
a differential output unit that outputs a differential signal between the output of the first acceleration sensor and the output of the second acceleration sensor;
The acceleration detection device further comprising a signal output unit that outputs a normal signal of the output of the first acceleration sensor and a reverse signal of the output of the second acceleration sensor. a first acceleration sensor;
A second acceleration sensor having a measurement frequency band or an acceleration detection range different from that of the first acceleration sensor,
the first acceleration sensor and the second acceleration sensor are arranged such that positive directions of acceleration detection axes are opposite to each other;
receiving the output of the first acceleration sensor and the output of the second acceleration sensor, a differential signal of the output of the first acceleration sensor and the output of the second acceleration sensor, and forward rotation of the output of the first acceleration sensor; The acceleration detection device further comprising an input processing unit that outputs a signal and an inverted signal of the output of the second acceleration sensor. A bearing device comprising the acceleration detection device according to any one of claims 1 to 5 .

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