Method and data processing device for determining a spacing of rolling elements

• US 10,564,069 B2
• Filed: 10/09/2015
• Issued: 02/18/2020
• Est. Priority Date: 10/13/2014
• Status: Active Grant

• Current Assignee: ABet SKF
• Original Assignee: ABet SKF
• Inventors: Thomson, Allan
• Primary Examiner(s): Alkafawi, Eman A
• Application Number:
  US14/879,157
• Publication Number:
  US 20160103037A1
• Time in Patent Office: 1,593 Days
• Field of Search: 702158, 702 33- 34
• CPC Class Codes: F16C 19/52 with devices affected by abnormal or undesired conditions
• CPC Class Codes: G01B 7/14 for measuring distance or clearance between spaced objects or spaced apertures G01B7/30 takes precedence
• CPC Class Codes: G01M 13/04 Bearings
• CPC Class Codes: G01M 13/045 Acoustic or vibration analysis

Abstract

A method for detecting roller spacings in a roller bearing having at least one row of rollers wherein the rollers in the row are held by at least one cage, preferably by a plurality of roller cages. The method uses roller load induced strain signals for determining the roller spacings.

Claims

1. A method for detecting roller spacings in a roller bearing having at least one row of rollers held by at least one roller cage, the method executable by a data processing device in communication with at least one strain sensor, the method comprising:

receiving, by the data processing device, roller load induced strain signals from the at least one strain sensor for determining the roller spacings;

filtering the roller load induced strain signals via high pass or band-pass filtering to produce a filtered strain signal;

determining, by the data processing device, the roller spacings by determining zero crossings from the filtered strain signal, adjacent roller centers as midpoints between the zero crossings, and each roller spacing as a difference between the adjacent roller centers;

determining, by the data processing device, a slope of a linear function connecting a point of the zero crossings and a height of a peak following the point, the peak being discarded when the slope is less than a predetermined minimum slope; and

issuing, by the data processing device, a warning signal comprising that the least one roller cage is broken or that the rollers are broken or missing, when one of the roller spacings determined from the filtered strain signal and remaining from the discarded peaks is determined to be smaller than a minimum spacing or larger than a maximum spacing, the warning comprising a confidence level for the difference by comparing the number of successfully determined roller spacings with a number of rollers in a raceway, the confidence level being a percentage confidence rating for each of the roller load induced strain signals on a per signal period basis.

2. The method according to claim 1, the method further comprises:

outputting the roller spacings.

3. The method according to claim 2, the method further comprises:

a. determining peak heights and peak positions of peaks of the strain signal;

b. determining trough depths and trough positions of troughs in the strain signal;

c. comparing the peak heights and trough depths with predetermined threshold values respectively; and

d. making use of the roller centers associated to adjacent peaks in the step of determining the roller spacing only under the condition that the peak heights of the adjacent peaks and the trough depth between the peaks are above the respective threshold values.

4. The method according to claim 1, the method further comprising:

mapping at least one of the roller load induced strain signals and from time-dependent signals onto angle dependent signals prior to determining the roller spacings,

wherein the roller spacings are output in unit of angles.

5. A data processing device comprising:

a wireless transmitter configured to be attached to a roller bearing having at least one row of rollers held by at least one roller cage,

the data processing device including at least one interface for receiving roller load induced strain signals from at least one strain sensor,

wherein the data processing device is configured to receive roller load induced strain signals from the at least one strain sensor for determining the roller spacings;

determine the roller spacings by determining zero crossings from a filtered strain signal, adjacent roller centers as midpoints between the zero crossings, and each roller spacing as a difference between the adjacent roller centers;

filter the roller load induced strain signals via high pass or band-pass filtering to produce a filtered strain signal;

determine the roller spacings by determining zero crossings from the filtered strain signal, adjacent roller centers as midpoints between the zero crossings, and each roller spacing as a difference between the adjacent roller centers;

determine a slope of a linear function connecting a point of the zero crossings and a height of a peak following the point, the peak being discarded when the slope is less than a predetermined minimum slope; and

issue a warning signal comprising that the least one roller cage is broken or that the rollers are broken or missing, when one of the roller spacings determined from the filtered strain signal and remaining from the discarded peaks is determined to be smaller than a minimum spacing or larger than a maximum spacing, the warning comprising a confidence level for the difference by comparing the number of successfully determined roller spacings with a number of rollers in a raceway, the confidence level being a percentage confidence rating for each of the roller load induced strain signals on a per signal period basis.

6. The data processing device according to claim 5 further comprising:

the at least one strain sensor for capturing the roller load induced strain signal, wherein the data processing device is in signal communication with the at least one strain sensor.

7. A system including:

a roller bearing equipped with at least one strain sensor for capturing roller load induced strain signals, the roller bearing comprising at least one roller cage and at least one row of rollers held by the at least one roller cage; and

a data processing device including;

a wireless transmitter configured to be attached to the roller bearing,

the data processing device including at least one interface for receiving roller load induced strain signals from the at least one strain sensor,

wherein the data processing device is configured to;

receive roller load induced strain signals from the at least one strain sensor for determining the roller spacings;

filter the roller load induced strain signals via high pass or band-pass filtering to produce a filtered strain signal;

determine the roller spacings by determining zero crossings from the filtered strain signal, adjacent roller centers as midpoints between the zero crossings, and each roller spacing as a difference between the adjacent roller centers;

determine a slope of a linear function connecting a point of the zero crossings and a height of a peak following the point, the peak being discarded when the slope is less than a predetermined minimum slope; and

issue a warning signal comprising that the least one roller cage is broken or that the rollers are broken or missing, when one of the roller spacings determined from the filtered strain signal and remaining from the discarded peaks is determined to be smaller than a minimum spacing or larger than a maximum spacing, the warning comprising a confidence level for the difference by comparing the number of successfully determined roller spacings with a number of rollers in a raceway, the confidence level being a percentage confidence rating for each of the roller load induced strain signals on a per signal period basis.