Process for early detection of damage to machine parts

• US 5,058,434 A
• Filed: 02/27/1990
• Issued: 10/22/1991
• Est. Priority Date: 02/27/1990
• Status: Expired due to Fees

• Current Assignee: CARL Schenck AG (Durr AG)
• Original Assignee: CARL Schenck AG (Durr AG)
• Inventors: Zaschel, Jorg
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): Finley, Rose M.
• Application Number:
  US07/485,586
• Time in Patent Office: 602 Days
• Field of Search: 73/584, 73/659, 73/660, 340/682
• US Class Current: 73/659
• CPC Class Codes: G01N 29/12 by measuring frequency or resonance of acoustic waves measuring frequency or resonant frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04, G01H13/00; acoustic resonators G10K11/04; vibration or shock testing of structures G01M7/00
• CPC Class Codes: G01N 29/4436 with a reference signal amplitude comparison G01N29/48
• CPC Class Codes: G01N 29/449 Statistical methods not provided for in G01N29/4409, e.g. averaging, smoothing and interpolation
• CPC Class Codes: G01N 29/52 using inversion methods other that spectral analysis, e.g. conjugated gradient inversion

Abstract

In a process for early detection of damage top machine parts, particularly rolling element bearings, vibrations are detected by means of a vibration pickup in order to make it possible to describe the present condition of the machine part as well as to estimate the remaining service life of the machine part. The picked-up signals are broken down into periodically determined stochastic and generally stochastic signal components. The signal components for determining the parameters for the stress of the machine part are examined as a function of time and the ascertained stress parameters are compared with characteristics values for the permissible stress of the machine part for purposes of determining the type of damage and/or for determining the extent of the damage.

Claims

1. A process for early detection of damage to a machine part comprising the steps of detecting vibrations of the machine part by means of a vibration pickup which picks up vibrations of the machine part and transforms them into corresponding picked up signals, breaking down the picked up signals into periodically determined signal components, and periodically recurring components having stochastic amplitudes, examining the signal components for determining the parameters for stress of the machine part as a function of frequency, and using the parameters for stress of the machine part for determining type of damage and/or comparing the parameters for stress of the machine part with characteristic values for permissible stress of the machine part for purposes of determining extent of damage of the machine part.

2. A process as in claim 1 including the steps of digitizing and storing for further processing the signals picked up by the vibration pickup.

3. A process as in claim 2 including the step of, prior to further processing, eliminating spurious and/or noise signal components from the signal that has been picked up.

4. A process as in claim 3 wherein the forced vibrations are picked up in two measuring channels and the spurious and/or noise signals are eliminated by correlating the two picked up signals.

5. A process as in claim 3 wherein the forced vibrations are picked up as a function of time in a measuring channel and compared with a calculated time function containing no spurious and/or noise signal components.

6. A process as in claim 5 including carrying out for preselected frequency ranges frequency analyses of damage-characteristic parameters based on the signal components, and on the basis of the frequency distribution, ascertaining damage-determining intensities which are linked with each individual frequency range for purposes of determining stress parameters.

7. A process as in claim 6 including using at least one of the signal components to ascertain the damage-determining intensities.

8. A process as in claim 7 including subjecting spectral components of the signals picked up by the vibration pickup to a frequency analysis, in which class boundary deviations are determined, standardizing the frequency distributions, converting certain frequency distributions into linear distributions, and determining a component-typical stress parameter for each frequency range.

9. a process as claim 8 wherein the step of determining a component-typical stress parameter for each frequency range further includes summing up the determined component-typical stress parameters to form a total stress parameter.