Does widening front end stress axle/bearings more?

xring100 · Dec 10, 2013

Ilikeurtractor said:
Thanks for the secondary analysis and design tips/goals. I put some numbers to the variables and came up with the attached. I tried running it with your method, but I wasn't sure how to resolve the vertical forces and moments. Anyway, I'm getting an outer bearing stress increase of 63% and inner bearing increase of around 157% based on the numbers I can find for an Iseki TX1300. I don't have exact values for bearing spacing or distance between the outer bearing and tire centerline in each case so I made some guesses. Obviously each tractor is going to have its own unique results. Of course, this could be way off reality but it was a fun exercise. I don't get to do much engineering at work so it's good to brush the dust off the tools once in a while even if the results are wrong :shocked:

No problem. I didn't draw a full FBD. Just trying to cover simple theory KISS. If I had seen your post before I did the drawing I wouldn't have done it. I do like seeing all the equations it brings back old memories

RaydaKub · Dec 10, 2013

xring100 said:
Very good i started reading this earlier and was getting frustrated reading through the thread and made this picture showing pretty much the same thing but you posted first.

In design you really want the centerline of the contact patch to be centered between the bearing races to minimize the moments as you have mentioned. On a side note I work as an engineer at GM my group owns the Brake and Bearing components.

Thank you! The picture, though crude :laughing:, is very effective in showing what I tried to verbalize.

Ilikeurtractor · Dec 10, 2013

xring100 said:
No problem. I didn't draw a full FBD. Just trying to cover simple theory KISS. If I had seen your post before I did the drawing I wouldn't have done it. I do like seeing all the equations it brings back old memories

After my last post I went back and re-did it again tailored more around using the center of the bearings as you had shown as the center of the moment. Unless I messed it up, the results are the same, just the offsets change by the distance between the bearings/2. I was thinking at first I would have needed to treat the bearings as one unit but ended up treating them separately yielding the same increases in stresses.