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US 2013/0211742 A1Published application
Load Sensing on a Bearing
AssigneeAktiebolaget Skf
InventorHendrik Anne Mol
Life of this patent
Estimating the term…
Abstract
The mechanical load on a rolling element bearing is determined from the deformation of the rolling element bearing. The local deformation caused by the rolling contact forces is used to determine an average contribution to the mechanical load in order to average out the effect on the deformation as a result of the spread in diameter of the rolling elements of the bearing. The global deformation of the rolling element bearing is determined to calculate a dynamic contribution to the mechanical load. The dynamic contribution takes into account the variations of the mechanical load on the relevant time-scales that have been omitted from the average contribution as a result of the averaging operation. The total mechanical load is the sum of the average contribution and the dynamic contribution.
Claims14
A machine comprising:
- a rolling element bearing,
- a sensor system, and
- a load determining system, wherein
- the rolling element bearing includes an inner ring, an outer ring and a plurality of rolling elements accommodated between the inner ring and the outer ring;
- wherein
- the sensor system being configured for sensing a local deformation of at least a particular one of the inner ring and the outer ring at at least a specific location on the particular one of the inner ring and the outer ring, and for supplying a sensor output representative of the sensing;
- wherein
- the load determining system being configured for:
- receiving the sensor output from the sensor system;
- and determining a mechanical load on the rolling element bearing in dependence on the sensor output, when the inner ring and the outer ring are coaxially rotating relative to one another;
- wherein
- the load determining system comprises:
- a first signal path configured for processing the sensor output for determining an average contribution to the mechanical load;
- a second signal path configured for processing the sensor output for determining a dynamic contribution to the mechanical load;
- and a combiner for linearly combining the average contribution and the dynamic contribution;
- the first signal path being configured for:
- low-pass filtering the sensor output with a first cut-off frequency;
- and processing the low-pass filtered sensor output as representative of the local deformation induced by a passing of the rolling elements past the specific location so as to determine the average contribution indicative of a low-frequency variation in the local deformation;
- the second signal path being configured for:
- band-pass filtering the sensor output with a second cut-off frequency, substantially equal to the first cut-off frequency, and with a third cut-off frequency higher than the second cut-off frequency;
- and
- processing the band-pass filtered sensor output as representative of a global deformation of the rolling element bearing indicative of the dynamic contribution;
- and the first cut-off frequency, the second cut-off frequency and the third cut-off frequency are substantially lower than the ball-pass frequency.
20 more elements
Software on a computer-readable medium configured for being executed on a computer for implementing a load determining system, wherein:
- the load determining system being configured for determining a mechanical load on a rolling element bearing, which has:
- an inner ring,
- an outer ring and
- a plurality of rolling elements accommodated between the inner ring and the outer ring, when the inner ring and the outer ring are coaxially rotating relative to one another;
- the load determining system being operative to determine the mechanical load under control of a sensor system configured for sensing a local deformation of at least a particular one of an inner ring and the outer ring at at least a specific location on the particular one of the inner ring and the outer ring and for supplying a sensor output representative of the sensing;
- the software comprises:
- first instructions for implementing a first signal path configured for processing the sensor output for determining an average contribution to the mechanical load;
- second instructions for implementing a second signal path configured for processing the sensor output for determining a dynamic contribution to the mechanical load;
- and
- third instructions for implementing a combiner for linearly combining the average contribution and the dynamic contribution;
- the first instructions comprise:
- fourth instructions for implementing a low-pass filtering of the sensor output with a first cut-off frequency;
- and
- fifth instructions for implementing a processing of the low-pass filtered sensor output as representative of the local deformation induced by a passing of the rolling elements past the specific location so as to determine the average contribution indicative of a low-frequency variation in the local deformation;
- the second instructions comprise:
- sixth instructions for implementing a band-pass filtering of the sensor output with a second cut-off frequency, substantially equal to the first cut-off frequency, and with a third cut-off frequency higher than the second cut-off frequency;
- and
- seventh instructions for implementing a processing of the band-pass filtered sensor output as representative of a global deformation of the rolling element bearing indicative of the dynamic contribution;
- and
- the first cut-off frequency, the second cut-off frequency and the third cut-off frequency are substantially lower than the ball-pass frequency.
17 more elements
A method of determining a mechanical load on a rolling element bearing, wherein:
- the rolling element bearing having an inner ring, an outer ring and a plurality of rolling elements accommodated between the inner ring and the outer ring;
- the method comprises:
- sensing a local deformation of at least a particular one of the inner ring and the outer ring at at least a specific location on the particular one of the inner ring and the outer ring for generating a sensor output representative of the sensing;
- and
- determining the mechanical load on the rolling element bearing in dependence on the sensor output when the inner ring and the outer ring are coaxially rotating relative to one another;
- the determining of the mechanical load comprises:
- processing the sensor output for determining an average contribution to the mechanical load;
- processing the sensor output for determining a dynamic contribution to the mechanical load;
- and
- linearly combining the average contribution and the dynamic contribution;
- the determining of the average contribution comprises:
- low-pass filtering the sensor output with a first cut-off frequency;
- and
- processing the low-pass filtered sensor output as representative of the local deformation induced by a passing of the rolling elements past the specific location so as to determine the average contribution indicative of a low-frequency variation in the local deformation;
- the determining of the dynamic contribution comprises:
- band-pass filtering the sensor output with a second cut-off frequency, substantially equal to the first cut-off frequency, and with a third cut-off frequency higher than the second cut-off frequency;
- and
- processing the band-pass filtered sensor output as representative of a global deformation of the rolling element bearing indicative of the dynamic contribution;
- and the first cut-off frequency, the second cut-off frequency and the third cut-off frequency are substantially lower than the ball-pass frequency.
16 more elements
Dependencies are inferred from the claim text.