Needle roller bearings are roller bearings which have a high load carrying capacity with very small section height. Needle roller bearings are short section height, but it's burthen content and rigidity is bigger than common bearing, small inertia, fit shaking movement, using this bearing can achieve small and lightness of technical design. Needle roller bearing is the bearing with holding shelf, without skidding phenomenon and attrition quotiety is same to common bearing, low move temperature, fit high speed circumvolve.