... the side of ring file with a small friction, suitable for high-speed rotation. According to the ring file under the ... as NU, NJ, NUP, N, NF, etc. and double row bearings such as NNU, NN, etc.. Cylindrical roller bearing's inner ring ... engine,generator,gas turbines and reducer,rolling mill,the vibration, etc.cylindrical roller phote:More details, please see http://hhyg.preview ...