JPS63304129A - Detecting device for abnormality of bearing - Google Patents

Abstract

PURPOSE:To detect initial peeling of a bearing by eliminating the influence of back noise, etc. by detecting only a specific band through a band pass filter, with respect to the output of a sensor for detecting an acoustic emission from the bearing. CONSTITUTION:An acoustic emission (AE) signal from a bearing is detected by an AE sensor 1, and inputted to a BPF 3 through a pre-amplifier 2. Subsequently, only a frequency band of 100kHz-500kHz having a correlation with the generation of initial peeling of the bearing is fetched and amplified by a main amplifier 4, thereafter, brought to an envelope detection by an envelope detecting circuit 5. Next, the output of the circuit 5 is compared with a reference value by a comparator 6, and when it is in a higher level than the reference value, it is decided to be initial peeling of the bearing, and an alarm is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a bearing abnormality detection device using acoustic emission (AE).

<Prior art> Conventionally, a bearing abnormality detection device using an acoustic emission signal (AE multiplied signal) detects AE with an AE sensor and compares it with a reference value using an AE multiplied signal comparator from the AE sensor. Separation of the bearing was detected.

<Problems to be Solved by the Invention> However, the conventional bearing abnormality detection device described above has a problem in that it cannot be detected unless the bearing raceway, etc. is considerably peeled off due to the influence of back noise etc. .

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a bearing abnormality detection device that can detect initial separation.

Means for Solving Problems〉 The present inventors have discovered that when initial peeling occurs in a bearing, an AE multiplied signal is generated from this initial peeling, and this AE multiplied signal spectrum is expressed as shown in Fig. 2.3. I discovered that These spectra have characteristics from 100KHz to 500KHz, so the 100KHz shown in Figure 3
Initial peeling of the bearing can be detected by detecting signals in the band of ~500 KHz.

Based on the above discovery, the present invention provides a sensor that detects acoustic emissions from a bearing, and a sensor that detects 100K of the output from the sensor, in order to detect initial peeling of the bearing.
A bandpass filter that passes an output in a band between Hz and 500KHz, and a determination means that compares the output between 100KHz and 500KHz extracted by the bandpass filter with a reference value to determine initial separation of the bearing. It is characterized by having the following.

<Example> Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

In Fig. 1, l is an AE sensor, 2 is a preamplifier, and 3
is a bandpass filter that passes the AE multiplied signal in the band from 100 KHz to 500 KHz, 4 is the main amplifier, 5 is an envelope detection circuit, and 6 is the reference value of the AE multiplied signal after envelope detection in the envelope detection circuit 5. This is a comparator serving as a discrimination means that makes a comparison and determines that initial peeling has occurred when the AE multiplied signal exceeds the reference value, and issues an alarm.

With the above configuration, the AE multiplied signal A from the bearing (not shown)
Detected by E sensor l. This AE multiplied signal has a waveform as shown in Fig. 2, and is input to the bandpass filter 3 via the preamplifier 2, and is 100 KHz to 500 KHz, which is correlated with the occurrence of initial peeling of the bearing as shown in Fig. 3.
Only frequency bands within the range are extracted. The output from the band pass filter 3 is further amplified by the main amplifier 4, and after envelope detection is performed by the envelope detection circuit 5,
It is input to comparator 6. In the comparator 6, the envelope detection circuit 5
The envelope detection signal from the bearing is compared with a reference value, and when this envelope detection signal is at a higher level than the reference value, it is determined that there is initial separation of the bearing, and an alarm is issued.

In this way, of the AE multiplied signals generated from the bearing, only the AE multiplied signals in the frequency band (100 to 500 KHz) that are correlated with initial peeling are extracted, so they are not affected by low frequency back noise of several tens of KHz or less. This makes it possible to reliably detect initial peeling of the bearing.

<Effects of the Invention> As is clear from the above, the bearing abnormality detection device of the present invention includes a sensor that detects acoustic emitters from the bearing, and a sensor that detects 100KH of the output from the sensor.
a bandpass filter that passes an output in a band between z and 500KHz, and a determination means that compares the output between 100KHz and 500KHz extracted by the bandpass filter with a reference value to determine initial separation of the bearing. As a result, initial peeling of the bearing can be reliably detected without being affected by back noise or the like.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a bearing abnormality detection device according to an embodiment of the present invention, FIG. 2 is an AE multiplied signal waveform diagram, and FIG. 3 is an AE multiplied signal power spectrum diagram. l...Sensor, 3...Band pass filter, 6...Discrimination means. Patent applicant Koyo Seiko Co., Ltd. and 2 others Patent attorney Aoyama Ao and 2 others Figure 3 Shusakushu (KHz)

Claims (1)

[Claims] (1) A sensor that detects acoustic emissions from bearings, and a sensor that detects acoustic emissions from 100KHz to 500K of the output from the above sensor.
A bandpass filter that passes the output in the band between Hz and a determination means that compares the output between 100KHz and 500KHz extracted by the bandpass filter with a reference value to determine initial separation of the bearing. A bearing abnormality detection device characterized by comprising: