Page 14 - needle bearings

Classification and Characteristics of Bearings
NTN

The components described hereunder are for needle roller bearing.

Needle rollers
The needle rollers with flat end face and round end face
are standard. These rollers are made of high-carbon
chrome bearing steel, surface-finished by grinding and
buffing after heat-treated. The standard accuracy of these
rollers is "Precision Grade".
¡A-Inter-diameter tolerance of the needle rollers is 2mm
maximum.
¡The roller type with crowned rolling surface is also
available, which can damp edge load.
¡These needle rollers are supplied as an individual for
applications (pin, shaft) other than rolling element.

Snap rings
These are special-purposed rings used for axially
positioning or guiding the inner and outer rings or the
needle roller and cage assembly in needle roller bearing.
The ring material is a hard steel wire rod and chemical
conversion treatment is applied to its surface so as to
provide high rigidity.
¡Two types are available for shaft and housing use.
¡The section height is lowered flexibly according to the
dimensions of needle roller bearings. In addition,
manufacture of these rings is available up to the
possible minimum dimensional range.
¡For the axial guide it is recommended to provide a
spacer between the cage and the snap ring.

Seals

This is a special-purposed seal which was designed so
as to match the small section height of needle roller
bearings.
¡G-type seal with one lip and GD-type seal with two lips
are selectively available on application.
¡These seals comprising steel ring and synthetic rubber
can be used at the operating temperature ranging from
-25 to 120˚C, but continuous use thereof is subject to
100˚C and less.
¡These seals act to prevent invasion of external foreign
matter and over-consumption of lubrication grease.
¡The radial section height of each seal is designed so as
to match the drawn-cup needle roller bearings. Hence,
these seals require no additional finishing of the
housing. This facilitates handling.

A-10