AGMA 96FTM10

In many transmission types, the lubricant fulfills otherfunctions apart from lubricating the gearing, for example infriction elements (synchroniztr unit, clutch) in vehicletransmissions, or as a hydraulic fluid (torque converter, retarder,steering system). The modem trends are now high contact ratiogearing as well as the use of low viscosity lubricants to reducechurning losses.

Therefore, at the gear design and lubricant additive stages,compromises are now necessary, which require the most preciseinformation possible on scuffing resistance of the gearing andlubricant.

It will be demonstrated that the normal test procedures fordetermining scufnng resistance are not suitable for lubricantciassifícation for vehicle transmission (GL4and GL5). By reducingthe tooth width as well as doubling the speed, the scuffing test toDIN 51354 sîandards was increased in severity to such an extent,that the parameters necessary for transmission dimensioning couldbe determined for even higher scuffing resistant oils.

The oil data necessary for suffícient scuffing resistaace wiiibe shown for different transmission design types. With in the scopeof life time oil fills, attention should be paid to oil agingprocesses.

The.profile and tooth trace of gears on modem transmission . onsare nowadays comcted, almost without exception, to compensate forload-related deformation and production discrepancies. in thecurrent calculation procedures these corrections, which tend toincrease scufnng resistance, are not considered to an adequateextent.

A process is being presented, in which scrifnng resistance iscalculated for every point on the tooth flank, based on the “flashtemperature method”, and taking ail variations and corrections intoaccount. It will be demonstrated with practical examples,that,asearly as the design stage,this method can be used to detect flankare as at risk,and toeliminate them with a specific correctiondesign.

Edition:

96

Published:

10/01/1996

Number of Pages:

10

File Size:

1 file , 790 KB