What is needle roller bearing?
Needle bearings use a roller style rolling element to reduce friction of a rotating
surface. Needle Bearings have a high load carrying capacity with a very small cross section
height. They are available with or without an inner ring. The
needle rollers are guided parallel to the axis using a cage
retainer, thrust bearings can also be supplied with no retainer,
which is referred to as a full complement of rollers.
Needle bearings have a larger surface area that is in contact with the bearing
outer surfaces compared to ball bearings. Additionally there is
less clearance, or the difference between the diameter of the shaft
and the diameter of the bearing, so they are much more compact. The
typical structure consists of an inner race (or sometimes merely a
shaft), a needle cage which orients and contains the needle
rollers, the needle rollers themselves, and an outer race.Needle bearings are heavily used in engine components such as rocker arm pivots,
pumps, compressors, and transmissions.
A needle roller bearing is a bearing which uses small cylindrical rollers.The difference
between a needle roller bearing and roller bearing is the ratio of diameter and length of their rollers, when the
ratio of the diameter and the length of roller of a roller bearing is between the interval of 0.1 to 0.4, that roller bearing is called a needle roller bearing. They are used to reduce the friction of a rotating surface.
Needle bearings have a large surface area that is in contact with the bearing
outer surfaces compared to ball bearings. Additionally there is
less added clearance (difference between the diameter of the shaft
and the diameter of the bearing) so they are much more compact. The
typical structure consists of a needle cage which orients and
contains the needle rollers, the needle rollers themselves, and an
outer race (sometimes the housing itself).
Radial needle bearings are cylindrical and use rollers parallel to the axis of the shaft.
Thrust needle bearings are flat and use a radial pattern of
needles.
Full complement bearings have solid inner and outer rings and
rib-guided cylindrical rollers. Since these bearings have the
largest possible number of rolling elements, they have extremely
high radial load carrying capacity and are suitable for
particularly compact designs.
