morris9791
Mechanical
Dear Folks,
I have 2 queries regarding the output results of the Timken bearing calculation program.
1) Static Rating
Based on Timken recommendations for calculating the static rating of bearings - one can compare the static radial rating Co against the Po the static equivalent radial load to obtain a factor of safety etc.
Using manual calcs (based on Timken method) we can get sufficient FoS e.g. 1.4 etc but when the Timken program is used we get the following kind of result.
“Condition 1 - right position: caution bearing has stress greater than 350ksi (2400MPa)”
“Condition 2 – left position: life prediction invalid, raceway exceeds 580ksi (4000MPa)
Note that we get the same radial ad axial forces as in program etc.
Does any one know what the ‘built in FoS’ is in this Timken program? It would be useful to know the minimum FoS is so that we can avoid this message in future.
We tend to compare this program against the manual calcs for verification reasons etc.
I could back calculate this value as a last resource I guess. I was hoping some-one has a more detailed understanding of what is happening.
2) Bearing Life
The Timken bearing life
in revolutions is given as L10 = (C90/P)^10/3 * 90e6 revs and
in Hours L10 = (C90/P)^10/3 * 1.5e6/n where n is in rpm.
Since the Timken program calculates in hours, I am wondering is it safe / correct to convert to revs since we can obtain L10 and n from program and work out the (C90/P)^10/3 term and hence use this to back calculate the life in revolutions?
Any information will be appreciated. Best Regards
Steady Eddie
I have 2 queries regarding the output results of the Timken bearing calculation program.
1) Static Rating
Based on Timken recommendations for calculating the static rating of bearings - one can compare the static radial rating Co against the Po the static equivalent radial load to obtain a factor of safety etc.
Using manual calcs (based on Timken method) we can get sufficient FoS e.g. 1.4 etc but when the Timken program is used we get the following kind of result.
“Condition 1 - right position: caution bearing has stress greater than 350ksi (2400MPa)”
“Condition 2 – left position: life prediction invalid, raceway exceeds 580ksi (4000MPa)
Note that we get the same radial ad axial forces as in program etc.
Does any one know what the ‘built in FoS’ is in this Timken program? It would be useful to know the minimum FoS is so that we can avoid this message in future.
We tend to compare this program against the manual calcs for verification reasons etc.
I could back calculate this value as a last resource I guess. I was hoping some-one has a more detailed understanding of what is happening.
2) Bearing Life
The Timken bearing life
in revolutions is given as L10 = (C90/P)^10/3 * 90e6 revs and
in Hours L10 = (C90/P)^10/3 * 1.5e6/n where n is in rpm.
Since the Timken program calculates in hours, I am wondering is it safe / correct to convert to revs since we can obtain L10 and n from program and work out the (C90/P)^10/3 term and hence use this to back calculate the life in revolutions?
Any information will be appreciated. Best Regards
Steady Eddie