METHOD AND SYSTEM FOR ABNORMALITY DIAGNOSIS OF VERY LOW SPEED ROTATING MACHINE

• US 20100116060A1
• Filed: 03/17/2008
• Published: 05/13/2010
• Est. Priority Date: 03/26/2007
• Status: Active Grant

• Current Assignee: Nippon Steel Corporation
• Original Assignee: Nippon Steel & Sumitomo Metal Corporation (Nippon Steel Corporation)
• Inventors: Murayama, Tsunemi
• Granted Patent: US 8,534,128 B2
• Time in Patent Office: Days
• US Class Current: 73/593
• CPC Class Codes: F16C 19/527 related to vibration and noise
• CPC Class Codes: G01H 1/003 of rotating machines G01H1/10 takes precedence
• CPC Class Codes: G01M 13/04 Bearings
• CPC Class Codes: G01M 13/045 Acoustic or vibration analysis

Abstract

The present invention provides a high accuracy, inexpensive diagnosis method and system diagnosing an abnormality of a 10 rpm or less very low speed roller bearing using an acoustic signal, that is, detects an acoustic signal emitted from a roller bearing of a 10 rpm or less ultralow speed rotating machine using a sensor having a sound pickup performance of 10 kHz or less, uses frequency analysis to find the spectrum distribution, processes this to obtain the frequency analysis waveform, compares the spectral average value or effective value of a frequency of the natural frequency of the bearing or more of this with a reference value, and judges that the bearing is abnormal when this spectral average value or effective value exceeds the reference value.

Claims

1. A method for abnormality diagnosis of a roller bearing of a very low speed rotating machine comprising detecting an acoustic signal emitted from a roller bearing of a rotating machine accompanying very low speed rotation of 10 rpm or less being diagnosed so as to diagnose any abnormality in the same,

said method for abnormality diagnosis of a roller bearing of a very low speed rotating machine characterized by

using a sensor having a sound pickup function to detect sound emitted from a bearing being detected as sound pressure, suitably amplifying it to obtain an acoustic signal, and finding a spectrum distribution of the same by frequency analysis,

finding a spectral average value or effective value of a frequency more than or equal to the natural frequency of the bearing from a frequency analysis waveform obtained by said frequency analysis, and

comparing said spectral average value or effective value with a separately found reference value and judging the bearing to be abnormal when exceeding said reference value.

2. A method for abnormality diagnosis of a roller bearing of a very low speed rotating machine as set forth in claim 1 characterized by bringing a sensor obtaining said acoustic signal into direct contact with said roller bearing.

3. A method for abnormality diagnosis of a roller bearing of a very low speed rotating machine as set forth in claim 1 or 2 characterized by outputting a signal obtained by amplifying said acoustic signal in an audible manner and screening it for judgment of an abnormality.

4. A method for abnormality diagnosis of a roller bearing of a very low speed rotating machine as set forth in claim 3 characterized in that said acoustic signal is one passed through a high frequency band pass filter of the natural frequency of the bearing or more.

5. A system for abnormality diagnosis of a roller bearing of a very low speed rotating machine detecting an acoustic signal emitted from a roller bearing of the rotating machine being diagnosed along with very low speed rotation of 10 rpm or less so as to diagnose an abnormality of it,

said system for abnormality diagnosis of a roller bearing of a very low speed rotating machine characterized by having:

a sensor having a sound pickup function,

an amplifier amplifying the acoustic signal obtained by said sensor,

a frequency analysis part finding a frequency distribution of said acoustic signal,

a storage part of a natural frequency of the bearing,

a processing part finding a spectral average value or effective value based on said frequency analysis,

a storage part storing a separately found reference value, and

an abnormality judgment part comparing said spectral average value or effective value with said reference value to judge if there is any abnormality.

6. A system for abnormality diagnosis of a roller bearing of a very low speed rotating machine as set forth in claim 5 characterized in that said sensor has the function of directly contacting said roller bearing to thereby obtain said acoustic signal as sound pressure.

7. A system for abnormality diagnosis of a roller bearing of a very low speed rotating machine as set forth in claim 5 or 6 characterized by being provided with an output part outputting said amplified acoustic signal in an audible manner.

8. A system for abnormality diagnosis of a roller bearing of a very low speed rotating machine as set forth in claim 7 characterized by being provided with a high frequency band pass filter extracting only a frequency band component of said amplified acoustic signal of more than or equal to the natural frequency of the bearing.