Page 10 - needle bearings

Classification and Characteristics of Bearings
NTN

Machined-ring needle roller bearing separable type

This bearing type comprises a machined outer ring
and machined needle rollers, and a cage to guide and
retain properly the needle rollers. And the needle roller
and cage assembly is separable from the outer ring. In
addition to the standard type, the type with no inner ring
is also available for enabling a shaft to be used as
direct raceway surface. (Of course, the type with inner
ring available, too.)
¡Easy to install, ʕ the needle roller and cage
assembly, the outer ring, and the inner ring can be
mounted independently from each other.
¡Any optional radial internal clearance is selectable by
combining the individual independent components.
¡Best-suited to space-saving design due to its low
section height, then having the large load capacity.
¡High rigidity and high bearing accuracy due to its
machined (precut) outer ring.
¡Can be used with a housing made of light metal, etc.
due to its outer ring of high rigidity.
¡Single row and double row types available. And the
outer ring of the double row bearing is provided with
lubrication hole and lubrication groove.

Inner ring
For the needle roller bearings, usually a shaft is used
as the raceway surface, but this inner ring is used
where the shaft surface can not be machined to the
specific hardness and roughness. This inner ring is
suited to space-saving design due to its low section
height. This is made of high carbon chrome bearing
steel, finished by high precision grinding after heat-
treated.
¡Can also be used as a bush.
¡Selectively available for both of the metric system
and the inch system.
¡The type with lubrication hole at the raceway center
also available.

Clearance-adjustable needle roller bearing
This bearing type comprises a machined outer ring
and machined needle rollers, and a cage to guide and
retain properly the needle rollers, but the needle roller
and cage assembly is non-separable from the outer
ring. In addition to the standard type, the type with no
inner ring is also available for enabling a shaft to be
used as direct raceway surface. (Of course, the type
with inner ring available, too.)
¡The raceway diameter of the outer ring is shrunk by
pressing the outer ring in axial direction, which then
enables to reduce the roller set bore diameter
correspondingly.
¡Radial clearance is finely adjustable by adjusting
axial pressing load and thereby changing shrinkage
of the outer ring raceway diameter.
¡This bearing is applied to the work spindle of a
machine tool and other similar portions which require
the high speed rotational accuracy of JIS Grade-4.

A-6