JPH073383B2 - Machine element abnormality diagnosis method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for diagnosing an abnormality in a mechanical element that moves such as rotate or swing.

[0002]

2. Description of the Related Art As a method for diagnosing a moving mechanical element, there are a method for measuring vibration, sound, AE, temperature and the like, and a ferrography method. Among them, in the vibration / acoustic method, the AE method has been used to diagnose abnormalities based on changes in the peak and effective values of signals, changes in crest factor and the like, the time intervals of abnormal signals, and the results of frequency analysis. Among them, for a signal generated in a mechanical element, for example, an AE signal, an abnormal signal having a large amplitude is generated within a fixed sampling time, and the distribution pattern of the generated time interval is obtained to perform abnormality diagnosis. Is being emphasized. (Patent No. 16
No. 13188) A block diagram thereof is shown in FIG.

[0003]

The above-mentioned prior art is AE
Under a situation where a large number of environmental noise signals similar to the signal are generated, the noise may cause the distribution pattern of the abnormal signal generation time interval to be buried or disturbed by noise, making reliable abnormality diagnosis impossible. There was a problem.

The present invention eliminates an environmental noise signal similar to the AE signal, and obtains an accurate distribution pattern regarding an abnormal signal generation time interval of the AE signal generated in a mechanical element that makes a motion such as rotation or rocking. The purpose is to perform reliable abnormality diagnosis.

[0005]

In order to achieve the above object, the present invention detects an AE signal generated in a mechanical element.
Equipped with an E signal detection unit and a noise signal detection unit that detects only the environmental noise signal that enters the AE signal detection unit, amplifies and filters the detected signal, and detects all signals that exceed the threshold value. A gate circuit that converts the signal into a pulse and connects the AE signal detection unit and the abnormal signal generation time interval measurement unit is opened each time a pulse is input from the noise signal detection unit to open the abnormal signal generation time interval measurement unit from the AE signal detection unit. It is characterized in that the pulse output to is cut off, noise unrelated to the abnormality is removed, and only the abnormal signal is extracted.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An apparatus for carrying out the present invention will be described with reference to FIG.
It is composed of an AE signal detection unit 1, a noise removal unit 4, and an abnormal signal generation time interval measurement unit 5. The AE signal detector 1 amplifies and filters the AE signal generated in the mechanical element and the environmental noise signal invading the AE signal, and converts all signals exceeding the threshold value into pulses. The noise removing section 4 comprises a noise signal detecting section 2 and a gate circuit 3. The sensor of the noise signal detector 2 is fixed at a position where the AE signal generated in the mechanical element does not propagate, and detects only the environmental noise signal. The noise signal detection unit 2 amplifies and filters the detected environmental noise signal and converts all noises exceeding the threshold value into pulses. Each time a pulse is input from the noise signal detection unit 2, the gate circuit 3 that connects the AE signal detection unit 1 and the abnormal signal generation time interval measurement unit 5 is opened to change the pulse input from the AE signal detection unit 1 to the abnormal signal generation time. It operates so as not to output to the interval measuring unit 5. In other words, the gate circuit 3
Is closed unless the environmental noise signal is detected by the noise removal unit 4, and sends the pulse input from the AE signal detection unit 1 to the abnormal signal generation time interval measurement unit 5. The gate circuit 3 comprises a gate time setting circuit 6, a delay circuit 7 and a gate 8 as shown in FIG. The same environmental noise signal is A
In consideration of the case where the E signal detecting section 1 and the noise signal detecting section 2 are detected with a time difference, a gate time setting circuit 6 is provided to set the time when the gate 8 is opened, and the AE signal detection is performed. A delay circuit 7 is arranged to delay the input signal from the unit 1.

The details of the operation timing of the noise removing section 4 are shown in FIG. Normally, the gate 8 is closed, and the pulse input from the AE signal detecting section 1 is output as it is to the abnormal signal occurrence time interval measuring section 5. When the noise signal detector 2 detects an environmental noise signal and a pulse is input from it, the gate 8
Does not output to the abnormal signal generation time interval measurement unit 5 the signal which has opened and entered the AE signal detection unit 1 and converted into a pulse.
The first half of FIG. 4 shows the case where the environmental noise signals are simultaneously input to both detection units. The pulse of the AE signal detector 1 is the delay circuit 7
The gate time setting circuit 6
Noise is removed by setting a gate time longer than the delay time and opening the gate 8.

Therefore, even if the environmental noise signal enters both of them with a time difference, the noise can be removed by appropriately selecting the gate time and the delay time. In the latter half of FIG. 4, the AE signal is input only to the AE signal detector 1. Since the environmental noise signal does not enter the noise signal detection unit 2, the gate 8 is closed and the AE
The pulse input from the signal detection unit 1 is delayed by the delay circuit 7, but is output to the abnormal signal generation time interval measurement unit 5 as it is.

[0009]

According to the present invention, an AE signal detecting section for detecting an AE signal generated in a mechanical element and a noise signal detecting section for detecting only an environmental noise signal entering the AE signal detecting section are provided, From the noise signal detector, a gate circuit that amplifies and filters the detected signal, converts all signals that exceed the threshold value into pulses, and connects the AE signal detector and the abnormal signal occurrence time interval measurement unit Since the pulse that opens each time a pulse is input and is output from the AE signal detection unit to the abnormal signal occurrence time interval measurement unit is blocked, noise unrelated to the abnormality is removed, and only the abnormal signal is extracted, AE
Abnormal noise signal similar to the signal is removed, and an accurate distribution pattern regarding abnormal signal generation time intervals of AE signals generated by mechanical elements that move such as rotate or oscillate is obtained, and reliable abnormality diagnosis is performed. It can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram of an abnormal signal generation time interval measuring device.

FIG. 2 is a block diagram of an abnormality diagnosis device.

FIG. 3 is a block diagram of a gate circuit.

FIG. 4 is a timing diagram of a noise removing unit.

[Explanation of symbols]

 1 AE signal detection unit 2 Noise signal detection unit 3 Gate circuit 4 Noise removal unit 5 Abnormal signal generation time interval measurement unit 6 Gate time setting circuit 7 Delay circuit 8 Gate

Claims (1)

[Claims] 1. An AE signal detecting section for detecting an AE signal generated in a mechanical element, and a noise signal detecting section for detecting only an environmental noise signal entering the AE signal detecting section,
From the noise signal detector, a gate circuit that amplifies and filters the detected signal, converts all signals that exceed the threshold value into pulses, and connects the AE signal detector and the abnormal signal occurrence time interval measurement unit Abnormality of the mechanical element that opens every time a pulse is input and cuts off the pulse output from the AE signal detection unit to the abnormal signal occurrence time interval measurement unit, removes noise unrelated to the abnormality, and extracts only the abnormal signal Diagnostic method.