Are Axial Forces on a Drive Shaft Negligible in Bearing Design?

[ckpitt55]

Hey guys,

I working on a bearing design project for a mech. design class. The bearings will be used to support an automotive drive shaft, and I was wondering:

1) if there were any axial (thrust) forces introduced to the shaft by the engine and whether they are negligible or not
2) if they are not negligible, how to calculate them?

I feel as though its important to my bearing design, because if axial loads are non-negligible I am going to go with something like a tapered roller bearing, and rely on shaft shoulders and thrust shims to help take up the load.

Thinking about it I feel as though it exists, I'm just not sure how it manifests itself or how to account for it. Is my intuition misguided?

Thanks for the help

 

[Ranger Mike]

there is no appreciable axial thrust. typical drive shaft input shafts have splines that permit axial movement. the differential of a rear wheel drive vehicle will move up and down due to road conditions and this will move the input shaft in and out of the transmission. The same applies to front wheel drive trans axles that also have limited movement.

 

[alzizou]

hi

If you trun on an engine ( for example a small one : 50cc ) , you can see that there is not any impressive axial force on the drive shaft of the engine. you can keep the engine on for a long time on the ground without any fixture.