Diagnostic method and diagnostic device for a slide bearing

• US 9,588,015 B2
• Filed: 02/21/2011
• Issued: 03/07/2017
• Est. Priority Date: 03/03/2010
• Status: Active Grant

• Current Assignee: Asahi Kasei Engineering Corporation (Asahi Kasei Corporation)
• Original Assignee: Asahi Kasei Engineering Corporation (Asahi Kasei Corporation)
• Inventors: Sako, Takashi, Tamura, Kouichi
• Primary Examiner(s): Bhat, Aditya
• Application Number:
  US13/582,288
• Publication Number:
  US 20130006551A1
• Time in Patent Office: 2,206 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G01H 1/14 Frequency
• CPC Class Codes: G01M 13/045 Acoustic or vibration analysis

Abstract

A sign of a minor rubbing abnormality of a slide bearing in a diesel engine is accurately detected. In order to realize the accurate detection, the following is performed: detecting waveform data which represents an acceleration of a vibration which occurs when a slide bearing is in operation; transforming acceleration waveform data into an acceleration spectrum of a frequency domain by applying a Fourier transform to the acceleration waveform data; quantifying a plurality of peak information which occurs at a rotational frequency interval of a shaft to be measured in the acceleration spectrum by performing a predetermined signal process combined with rotational frequency information of the shaft; obtaining a characteristic value; monitoring whether the obtained characteristic value has exceeded a predetermined threshold value; and when the characteristic value has exceeded the threshold value, determining that an abnormality has occurred in the slide bearing.

Claims

1. A diagnostic method for a slide bearing, the diagnostic method comprising:

detecting acceleration waveform data which represents an acceleration of a vibration which occurs when a slide bearing is in operation;

transforming the acceleration waveform data into an acceleration spectrum of a frequency domain by applying a Fourier transform to the acceleration waveform data;

performing a cepstrum calculation which applies an inverse Fourier transform to the acceleration spectrum after a logarithmic transformation, and obtaining time series data of a quefrency value obtained from the waveform data after the cepstrum calculation; and

when the quefrency value has exceeded a predetermined threshold value, determining that a rubbing has occurred in the slide bearing.

4. The diagnostic method for a slide bearing according to any one of claims 1, 2 and 3, wherein data of a frequency domain of 1 k to 30 kHz is detected as data which represents the vibration acceleration.

5. The diagnostic method for a slide bearing according to any one of claims 1, 2 and 3, wherein data of a frequency domain of at least 1 k to 10 kHz is detected as data which represents the vibration acceleration.

6. The diagnostic method for a slide bearing according to any one of claims 1, 2 and 3, wherein a slide bearing of a diesel engine is a target that is diagnosed.

2. A diagnostic method for a slide bearing, comprising:

detecting acceleration waveform data which represents an acceleration of a vibration which occurs when a slide bearing is in operation;

transforming the acceleration waveform data into an acceleration spectrum of a frequency domain by applying a Fourier transform to the acceleration waveform data;

performing a calculation which determines an auto-correlation of the acceleration spectrum, and

when the value of the auto-correlation obtained from the calculation has exceeded a predetermined threshold value, determining that a rubbing has occurred in the slide bearing.

3. A diagnostic method for a slide bearing, comprising:

detecting acceleration waveform data which represents an acceleration of a vibration which occurs when a slide bearing is in operation and also detecting a rotational frequency of a rotating shaft;

transforming the acceleration waveform data into an acceleration spectrum of a frequency domain by applying a Fourier transform to the acceleration waveform data;

performing a calculation which determines a cross-correlation between the detected acceleration spectrum and a predetermined artificial spectrum having a peak for every rotational frequency of the shaft as the spectrum of the frequency domain of the vibration acceleration, and

when the value of the cross-correlation obtained from the calculation has exceeded a predetermined threshold value, determining that a rubbing has occurred in the slide bearing.

7. The diagnostic method for a slide bearing according to claim 3, wherein

a characteristic value is calculated in a predetermined frequency range comprising a frequency domain with the highest cross-correlation.

8. A diagnostic device for a slide bearing which diagnoses an abnormality such as a rubbing in the slide bearing, the diagnostic device comprising:

a revolution speed detection sensor which detects a revolution speed of a rotating shaft;

an acceleration sensor which detects an acceleration during a vibration of the rotating shaft;

a monitoring device which;

transforms waveform data which represents an acceleration of a vibration detected by the acceleration sensor into an acceleration spectrum of a frequency domain by applying a Fourier transform to the waveform data;

performs a cepstrum calculation which applies an inverse Fourier transform to the acceleration spectrum after a logarithmic transformation, and obtains time series data of a quefrency value obtained from the waveform data after the cepstrum calculation;

monitors whether the quefrency value has exceeded a predetermined threshold value; and

when the quefrency value has exceeded the threshold value, determines that a rubbing has occurred in the slide bearing; and

a reporting device which outputs a determination result to the outside when the monitoring device has determined that a rubbing has occurred in the slide bearing.

9. A diagnostic device for a slide bearing which diagnoses an abnormality such as a rubbing in the slide bearing, the diagnostic device comprising:

a revolution speed detection sensor which detects a revolution speed of a rotating shaft;

an acceleration sensor which detects an acceleration during a vibration of the rotating shaft;

a monitoring device which;

transforms waveform data which represents an acceleration of a vibration detected by the acceleration sensor into an acceleration spectrum of a frequency domain by applying a Fourier transform to the waveform data;

performs a calculation which determines an auto-correlation of the acceleration spectrum;

monitors whether the value of the auto-correlation obtained from the calculation has exceeded a predetermined threshold value; and

when the value of the auto-correlation has exceeded the threshold value, determines that a rubbing has occurred in the slide bearing; and

a reporting device which outputs a determination result to the outside when the monitoring device has determined that a rubbing has occurred in the slide bearing.

10. A diagnostic device for a slide bearing which diagnoses an abnormality such as a rubbing in the slide bearing, the diagnostic device comprising:

a revolution speed detection sensor which detects a revolution speed of a rotating shaft;

an acceleration sensor which detects an acceleration during a vibration of the rotating shaft;

a monitoring device which;

transforms waveform data which represents an acceleration of a vibration detected by the acceleration sensor into an acceleration spectrum of a frequency domain by applying a Fourier transform to the waveform data;

prepares, in advance, a predetermined artificial spectrum having a peak for every rotational frequency of the shaft as the spectrum of the frequency domain of the vibration acceleration;

performs a calculation which determines a cross-correlation between the acceleration spectrum and the artificial spectrum;

monitors whether the value of the cross-correlation obtained from the calculation has exceeded a predetermined threshold value; and

when the value of the cross-correlation has exceeded the threshold value, determines that a rubbing has occurred in the slide bearing; and

a reporting device which outputs a determination result to the outside when the monitoring device has determined that a rubbing has occurred in the slide bearing.

11. The diagnostic device for a slide bearing according to any one of claims 8, 9 and 10, wherein a slide bearing of a diesel engine is a target to be diagnosed.