There are two kinds of bearings such as single row and duoble row,the ability that single row angular contact ball bearings bear axial angle alignment error is limited,any axial angle alignment error will cause increasing operation noise of bearing,they are mostly used in pair.Under severer condition, if rotation speed is extremely high or operation temperature is extremely high, lubricant grease may be leaked from inner ring. Adopt special design measures if grease leakage is not allowed for bearing configuration.