GEAR FAULT DETECTION

• US 20150088435A1
• Filed: 09/24/2013
• Published: 03/26/2015
• Est. Priority Date: 09/24/2013
• Status: Active Grant

• Current Assignee: Sikorsky Aircraft Corporation (Martin Marietta Corporation)
• Original Assignee: Sikorsky Aircraft Corporation (Martin Marietta Corporation)
• Inventors: Chaudhry, Zaffir A., Sun, Fanping, Chen, Yan, Isom, Joshua D., Zhang, Guicai, Shashanka, Madhusudana
• Granted Patent: US 9,482,647 B2
• Time in Patent Office: Days
• US Class Current: 702/35
• CPC Class Codes: F16H 2057/012 of gearings
• CPC Class Codes: F16H 57/01 Monitoring wear or stress of gearing elements, e.g. for triggering maintenance
• CPC Class Codes: G01H 1/003 of rotating machines G01H1/10 takes precedence
• CPC Class Codes: G01M 13/021 Gearings
• CPC Class Codes: G01M 13/028 Acoustic or vibration analysis
• CPC Class Codes: G01N 2291/015 Attenuation, scattering
• CPC Class Codes: G01N 2291/0234 Metals, e.g. steel
• CPC Class Codes: G01N 2291/0258 Structural degradation, e.g. fatigue of composites, ageing of oils
• CPC Class Codes: G01N 2291/2696 Wheels, Gears, Bearings
• CPC Class Codes: G01N 29/04 Analysing solids using acoustic emission techniques G01N29/14
• CPC Class Codes: G01N 29/14 using acoustic emission techniques echo of particles G01N29/046; measuring mechanical vibrations or acoustic waves in solids in general G01H1/00
• CPC Class Codes: G01N 29/4454 Signal recognition, e.g. specific values or portions, signal events, signatures
• CPC Class Codes: G01N 29/46 by spectral analysis, e.g. Fourier analysis or wavelet analysis spectral signal processing per se G06F17/14
• CPC Class Codes: G01N 29/50 using auto-correlation techniques or cross-correlation techniques

Abstract

Embodiments are directed to obtaining an impact energy signal associated with each of a plurality of teeth of a gear over a revolution of a shaft associated with the gear, generating, by a computing device comprising a processor, a profile of the impact energy signal, and declaring a fault associated with an identified tooth included in the plurality of teeth based on an analysis of the profile.

Claims

1. A method comprising:

obtaining an impact energy signal associated with each of a plurality of teeth of a gear over a revolution of a shaft associated with the gear;

generating, by a computing device comprising a processor, a profile of the impact energy signal; and

declaring a fault associated with an identified tooth included in the plurality of teeth based on an analysis of the profile.

2. The method of claim 1, further comprising:

generating an estimated impact energy signal corresponding to each tooth of the plurality of teeth;

comparing the estimated impact energy signal with the obtained impact energy signal; and

declaring the fault based on the comparison indicating a deviation between the estimated impact energy signal and the obtained impact energy signal in an amount greater than a threshold.

3. The method of claim 1, further comprising:

segmenting the impact energy signal into a number of segments equal to a number of teeth included in the plurality of teeth; and

integrating each segment included in the number of segments to calculate the total energy released by each gear tooth impact.

4. The method of claim 1, further comprising:

separating the signal into a time synchronous average signal and a random signal; and

processing the random signal to obtain an energy history associated with a meshing of the teeth.

5. The method of claim 1, further comprising:

computing slices of a spectral correlation density associated with the shaft at a fundamental frequency and multiples of the fundamental frequency to obtain a cyclic frequency domain representation; and

converting the cyclic frequency domain representation to a rotation domain to produce a time-frequency representation for the shaft.

6. The method of claim 5, further comprising:

integrating a spectral frequency out of the time-frequency representation to obtain a time synchronous variance; and

using the time synchronous variance to detect and isolate a fault associated with the shaft.

7. The method of claim 5, further comprising:

integrating an angular rotation out of the time-frequency representation to obtain a time synchronous spectrum; and

using the time synchronous spectrum to monitor vibration of a gearbox.

8. The method of claim 5, further comprising:

integrating a spectral frequency out of the time-frequency representation in bands coinciding with identified spectral peaks equal to a number of substantially similar gear meshes; and

using the integrated spectral frequency to obtain a unique time synchronous variance for each of the gear meshes.

9. An apparatus comprising:

at least one processor; and

memory having instructions stored thereon that, when executed by the at least one processor, cause the apparatus to;

obtain an impact energy signal associated with each of a plurality of teeth of a gear over a revolution of a shaft associated with the gear,

generate a profile of the impact energy signal, and

declare a fault associated with an identified tooth included in the plurality of teeth based on an analysis of the profile.

10. The apparatus of claim 9, wherein the instructions, when executed by the at least one processor, cause the apparatus to:

generate an estimated impact energy signal corresponding to each tooth of the plurality of teeth,

compare the estimated impact energy signal with the obtained impact energy signal, and

declare the fault based on the comparison indicating a deviation between the estimated impact energy signal and the obtained impact energy signal in an amount greater than a threshold.

11. The apparatus of claim 9, wherein the instructions, when executed by the at least one processor, cause the apparatus to:

segment the impact energy signal into a number of segments equal to a number of teeth included in the plurality of teeth, and

integrate each segment included in the number of segments to calculate the total energy released by each gear tooth impact.

12. The apparatus of claim 9, wherein the instructions, when executed by the at least one processor, cause the apparatus to:

separate the impact energy signal into a time synchronous average signal and a random signal, and

process the random signal to obtain an energy history associated with a meshing of the teeth.

13. The apparatus of claim 9, wherein the instructions, when executed by the at least one processor, cause the apparatus to:

compute slices of a spectral correlation density associated with the shaft at a fundamental frequency and multiples of the fundamental frequency to obtain a cyclic frequency domain representation, and

convert the cyclic frequency domain representation to a rotation domain using an inverse Fourier transform to produce a time-frequency representation for the shaft.

14. The apparatus of claim 13, wherein the instructions, when executed by the at least one processor, cause the apparatus to:

integrate a spectral frequency out of the time-frequency representation to obtain a time synchronous variance, and

use the time synchronous variance to detect and isolate a fault associated with the shaft.

15. The apparatus of claim 13, wherein the instructions, when executed by the at least one processor, cause the apparatus to:

integrate an angular rotation out of the time-frequency representation to obtain a time synchronous spectrum, and

use the time synchronous spectrum to monitor vibration of a gearbox associated with the gear and the shaft.

16. The apparatus of claim 13, wherein the instructions, when executed by the at least one processor, cause the apparatus to:

integrate a spectral frequency out of the time-frequency representation in bands coinciding with identified spectral peaks equal to a number of gear meshes, and

use the integrated spectral frequency to obtain a unique time synchronous variance for each of the gear meshes.