Needle Rollers – These are Rolling element which provides the function of rotation and load. Needles/ Rollers are placed between the Shaft & Housing (with or w/o Cage or Rings)
It is Called Needle when l/d = or > 9 (l is length & d is diameter)
It is Called Roller when l/d < 9 (l is length & d is diameter)
Length of the Needle/ Roller determines the load capacity.
Needle Roller are made of SAE 52100 (High Carbon Chromium Steel). They are either Through Hardening (Needles/Rollers). Standard Hardness of Needle Roller is between HRc 58 – 65
Needle rollers can be used to design full complement bearing arrangements for low-speed or oscillating applications. These compact bearing arrangements have a very high load carrying capacity when compared to bearings with a cage and are economical, provided the shaft and housing bore can serve as raceways (Raceways on shafts and in housings).