gearcutter
Industrial
- May 11, 2005
- 683
I've been trying to get my head around lubrication regimes related to gears and I need some help in trying to figure out what the numbers mean.
I understand why it's important that a design ensures that Lambda is = to or greater than 1. What I don't understand is this; I have accumulated a fairly large range of different designs which I have reversed engineered from various OEM examples to use as a guide for new designs. When calculating Lambda from these examples around 90% of them show Lambda to be well under 1, sometimes as low as 0.2. Yet none of the examples I have chosen showed signs of damaging surface fatigue other than the usual polished type of finish. By polished I mean that the flanks are shiny and no evidence of the original grinding marks remain. All the examples used were case hardened & finish ground.
AGMA 925 suggests anything less than Lambda 0.4 is classified as regime I or boundary. At a pitch line velocity of around 10 m/s and Lambda of less than 0.4 AGMA 925 suggests there is a greater than 80% risk of wear.
My question is: How would you define the wear in this case and what effect does it have on the overall longevity of the sufaces?
I’m guessing that the wear is related to initial asperity contact and could be beneficial over the longer term assuming flash temperatures have been kept low enough to avoid scuffing or scoring.
I understand why it's important that a design ensures that Lambda is = to or greater than 1. What I don't understand is this; I have accumulated a fairly large range of different designs which I have reversed engineered from various OEM examples to use as a guide for new designs. When calculating Lambda from these examples around 90% of them show Lambda to be well under 1, sometimes as low as 0.2. Yet none of the examples I have chosen showed signs of damaging surface fatigue other than the usual polished type of finish. By polished I mean that the flanks are shiny and no evidence of the original grinding marks remain. All the examples used were case hardened & finish ground.
AGMA 925 suggests anything less than Lambda 0.4 is classified as regime I or boundary. At a pitch line velocity of around 10 m/s and Lambda of less than 0.4 AGMA 925 suggests there is a greater than 80% risk of wear.
My question is: How would you define the wear in this case and what effect does it have on the overall longevity of the sufaces?
I’m guessing that the wear is related to initial asperity contact and could be beneficial over the longer term assuming flash temperatures have been kept low enough to avoid scuffing or scoring.