Posted by Jim Pollock on September 06, 2011 at 17:26:35:
I recently made a set 6dp spur gears with 29 and 32 teeth out of 8620 for a pulling tractor transmission. These were carburized and hardened to 54 Rc about .010 deep.
These gears broke after about 13 pulls. This tractor is producing probably 2,000 hp.
Does anyone know of any better material or heat treating that would make these stronger?
Also the hob that I used had a full fillet and I wondering if this is good bad as far as strength goes?
Also the hob that I used was a 20 degree pressure angle and I am assuming that if I used a 25 degree pressure angle hob, the teeth would be stronger.
I also believe that the shafts that these are mounted on are deflecting under load and causing the gear teeth to come out of full mesh under a load.
Any other ideas?