James Explains - Needle Roller Bearings 

A needle roller bearing needs an axial location feature. this is often done with a step on the shaft or with a circlip/snapring or in the housing . sometimes we utilise an existing feature such as a gear. Please bear in mind that any given shaft will need an axial bearing if any axial reaction force is seen to locate the shaft. Hope this helps!

some needle rollre bearing can rotating in one direction, and locked in the other direction