JPH05126678A - Abnormality detecting device for bearing - Google Patents

Abstract

PURPOSE:To provide an abnormality detecting device of a bearing capable of nearly completely removing the noise component from an AE signal. CONSTITUTION:An envelope detection wave-form shaping circuit 6 constituted of a low-pass filter is provided at the next stage of an envelope detecting circuit 5. An AE signal envelope-detected by the envelope detecting circuit 5 is removed with the noise component having a shorter duration than the duration of the abnormality AE signal caused by the abnormality of a bearing by the envelope detection wave-form shaping circuit 6 constituted of a low-pass filter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing abnormality detecting apparatus utilizing acoustic emission (AE).

[0002]

2. Description of the Related Art Conventionally, as an abnormality detecting device for a bearing using an AE, an AE from the bearing is detected by an AE sensor, a noise is removed from the AE signal from the AE sensor by a bandpass filter, and the noise is removed. The detected AE signal is envelope-detected by the envelope detection circuit, and the AE signal from the envelope detection circuit is compared with a constant reference value by a comparator. When the AE signal exceeds the reference value, it is determined that the bearing is abnormal. There are some that are designed to detect.

[0003]

However, although the above-described conventional bearing abnormality detecting device removes noise from the AE signal before envelope detection by the bandpass filter, it is caused by electric pulse noise, so that low frequency A noise component having a wide frequency component up to a high frequency cannot be sufficiently removed from the AE signal, and when a certain reference value is set as it is and compared, the AE signal caused by the noise component is also regarded as an abnormal bearing. It has been found that there is a problem in that the abnormality detection of the bearing becomes inaccurate because it is detected.

SUMMARY OF THE INVENTION An object of the present invention is to provide a bearing abnormality detecting apparatus capable of removing noise components from an AE signal substantially completely and accurately detecting abnormality.

[0005]

According to the present invention, the duration of a noise component due to electric pulse noise that cannot be removed from an AE signal by a bandpass filter of a conventional bearing abnormality detection apparatus is AE due to a bearing abnormality. Focusing on the fact that the signal duration is shorter than the signal duration, based on the consideration that a low-pass filter can be used to remove from the AE signal after envelope detection a noise component that has a shorter duration than the AE signal due to bearing abnormality. Was made.

That is, the abnormality detecting device for a bearing of the present invention is the acoustic emission (A) received from the bearing.
E) to detect an AE signal and output an AE signal, an envelope detection unit that envelope-detects the AE signal from the AE sensor and outputs an envelope-detected AE signal, and the envelope detection unit. A low-pass filter for receiving an AE signal of the AE signal and removing an AE signal having a duration shorter than a duration of the AE signal due to the abnormality of the bearing having a predetermined duration from the AE signal, and the low-pass filter. The comparing means for comparing the AE signal from the filter with the reference value, and the detection signal indicating that the AE signal has exceeded the reference value from the comparing means, and the abnormality of the bearing based on the detection signal. It is characterized in that it is provided with a determining means for determining.

[0007]

The AE from the bearing is detected by the AE sensor and the AE signal is output. This AE signal is subjected to envelope detection by the envelope detection means. Then, the envelope-detected AE signal is removed by the low-pass filter from the AE signal, which has a duration shorter than the duration of the AE signal due to the abnormality of the bearing. That is, the noise component having a shorter duration than the AE signal due to the abnormality of the bearing is removed from the AE signal after the envelope detection.

The AE from the low pass filter
The signal is compared with the reference value by the comparison means, and when the AE signal exceeds the reference value, the detection signal is output from the comparison means. The abnormality of the bearing is discriminated by the discriminating means which has received the detection signal.

As described above, since the noise component having the duration shorter than the duration of the AE signal due to the abnormality of the bearing is removed from the AE signal that has passed through the low-pass filter, the bearing means is determined by the comparing means and the determining means. Abnormality is accurately detected.

[0010]

The present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 is a block diagram showing an embodiment of a bearing abnormality detecting apparatus according to the present invention. 1 is an AE sensor, 2 is a preamplifier, 3 is a bandpass filter for selecting an AE signal,
Reference numeral 4 is a main amplifier, and 5 is an envelope detection circuit. Also,
Reference numeral 6 is an envelope detection waveform shaping circuit constituted by a low-pass filter, 7 is a reference value setting circuit, 8 is a comparator as comparing means, 9 is a host computer (calculator) as discriminating means, and 10 is a CRT and a printer. It is a display device.

The AE sensor 1 detects the AE from the bearing and outputs an AE signal representing the magnitude of this AE.
The AE signal from the AE sensor 1 is amplified by the preamplifier 2 and then amplified by the bandpass filter 3 to, for example, 200 KH.
An abnormal AE signal in the band from z to 500 KHz is passed, and noise outside the band from 200 KHz to 500 KHz is removed. The AE signal from which the noise is removed by the bandpass filter 3 is further amplified by the main amplifier 4,
It is input to the envelope detection circuit 5 and subjected to envelope detection. This envelope-detected AE signal (the AE signal at the location indicated by arrow A in FIG. 1) is caused by the electrical pulse noise in the abnormal AE signal X caused by the bearing abnormality, as illustrated in FIG. 2 (A). The noise component to be superimposed is superimposed. Then, the envelope-detected AE signal is subjected to the envelope-detection waveform shaping circuit 6 configured by a low-pass filter to remove noise components having a duration shorter than the duration of the abnormal AE signal due to the abnormality of the bearing. Be done. That is, as illustrated in FIG. 2B, only the abnormal AE signal X due to the abnormality of the bearing is output from the envelope detection waveform shaping circuit 6.

Abnormal AE signal X caused by the above-mentioned abnormality of the bearing
Is compared with the reference value output from the reference value setting circuit 7 by the comparator 8, and the comparator 8 outputs a pulse signal when the abnormal AE signal exceeds the reference value. That is, the comparator 8 pulses the abnormal AE signal exceeding the reference value.

As described above, since the comparator 8 compares the abnormal AE signal from which the noise component is removed by the envelope detection waveform shaping circuit 6 including the low-pass filter with the reference value, the abnormal AE on which the noise component is superimposed is compared. Even if the signal exceeds the reference value, the comparator 8 does not output the pulse signal unless the abnormal AE signal due to the abnormality of the bearing exceeds the reference value. Therefore, it is possible to prevent the comparator 8 from outputting the pulse signal due to the influence of the noise component resulting from the electric pulse noise, and the comparator 8 only outputs when the abnormal AE signal due to the abnormality of the bearing exceeds the reference value. , The host computer 9 based on the output pulse signal,
Accurate diagnosis of bearing abnormality can be performed. The abnormality diagnosis operation of the host computer 9 will be described based on the flowchart shown in FIG.

First, in step S1, the pulse generation period of the pulse signal from the comparator 8 is calculated. Next, in step S2, it is determined whether the pulse generation cycle is equal to the rotation cycle of the inner ring or the cycle in which the roller passes through the inner ring, and the pulse generation cycle is determined to be the rotation cycle of the inner ring or the roller. When it is determined that is equal to the cycle of passing the inner ring, the process proceeds to step S6, and when it is determined that the pulse generation period is not equal to the rotation period of the inner ring and the period of the roller passing through the inner ring, the process proceeds to step S3.

In step S6, the display device 10 including a CRT and a printer displays that an abnormality has occurred in the inner ring, and the abnormality diagnosis is finished.

In step S3, it is determined whether or not the pulse generation cycle is equal to the cycle in which the roller passes the outer ring, and when it is determined that the pulse generation cycle is equal to the cycle in which the roller passes the outer ring, step S7. If it is determined that the pulse generation cycle is not equal to the cycle in which the rollers pass through the outer ring, the process proceeds to step S4.

In step S7, the display device 10 displays
The abnormality diagnosis is ended by displaying that an abnormality has occurred in the outer ring.

In step S4, it is determined whether the pulse generation cycle is equal to the rotation of the cage of the bearing or the rotation cycle of the roller, and the pulse generation cycle is determined to be the rotation cycle of the cage or the rotation of the roller. When it is determined that the pulse generation period is not equal to the rotation period of the cage and the rotation period of the rollers, the process proceeds to step S8.

In step S8, the display device 10 is
A fault is displayed and the fault diagnosis ends.

In step S5, it is determined whether or not the bearing abnormality diagnosis is completed. When it is determined that the abnormality diagnosis is completed, the abnormality diagnosis is completed, and when it is determined that the abnormality diagnosis is not completed. Return to step S2.

As described above, according to this embodiment, it is possible to accurately locate the faulty portion of the bearing.

[0023]

As is apparent from the above, according to the present invention, a low-pass filter is provided in the subsequent stage of the envelope detection means, and the AE signal envelope-detected by the envelope detection means is converted into the AE signal by the low-pass filter. Of these, since the noise component due to the electric pulse noise having a shorter duration than the duration of the AE signal due to the abnormality of the bearing is removed, the abnormality of the bearing can be accurately detected. Further, not only the noise component caused by the electric pulse noise but also the noise component caused by the mechanical noise having the duration shorter than the duration of the AE signal due to the abnormality of the bearing are similarly removed.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a bearing abnormality detection device of the present invention.

FIG. 2 is a diagram showing an AE signal waveform in the above embodiment.

FIG. 3 is a flowchart illustrating the operation of the host computer of the above embodiment.

[Explanation of symbols]

1 AE signal 2 Preamplifier 3 Bandpass filter 4 Main amplifier 5 Envelope detection circuit 6 Envelope detection waveform shaping circuit 7 Reference value setting circuit 8 Comparator 9 Host computer 10 Display device

Claims (1)

[Claims] 1. An AE sensor that detects acoustic emission (AE) received from a bearing and outputs an AE signal, an envelope detection of the AE signal from the AE sensor, and an envelope-detected AE signal is output. The envelope detecting means and the AE signal from the envelope detecting means are received, and the AE signal is received.
A low-pass filter for outputting an AE signal from which an AE signal having a duration shorter than the duration of the AE signal due to an abnormality of the bearing having a predetermined duration width is removed, and an AE signal from the low-pass filter and a reference value And comparing means for receiving a detection signal indicating that the AE signal has exceeded the reference value from the comparing means, and determining a bearing abnormality based on the detection signal. A bearing abnormality detection device characterized by the above.