2009 Kubota RTV 900, 2009 Kubota B26 TLB & 2010 model LS P7010
It is a spike tooth cylinder from a combine. They also came with rasp bars instead of those spikes. The grain is cut and pulled up the mouth of the combine head into this thrashing cylinder where those spikes turn between a similar set that is mounted stationary on the bottom of the combine. If you remove the gathering head from a combine, you would see this big wheel.
Gary is right - it's a spike-tooth cylinder from a grain thrasher. I'd guess from the flat belt pulleys it's actually from a stationary thrasher rather then a combine. I've never seen a combine that used flat belts on small pulleys like that.