Needle Roller Bearings - Ntn-snr.com

Snap rings
NTN
Snap Rings
These snap rings are used exclusively for fixing or
guiding a needle roller bearing ring or cage in axial
direction. Furthermore, these snap rings have the profile
identical to C-type concentric snap ring specified in JIS B
2806 and, in addition, snap rings with smaller section
height (b) and also available in smaller dimension range
are manufactured according to application of needle roller
bearings. These snap rings are manufactured using hard
steel wire rod and, after manufactured, chemical
conversion treatment is applied to the surface thereof.
Composition of nominal number
The snap ring nominal number is composed of type
code (WR or BR) and dimension code. The dimension
code represents applicable shaft diameter in Type WR
and applicable housing bore diameter in Type BR.
WR 38
Types of snap ring
Two types of snap ring are available; one is Type WR
designed for application to shaft and another is Type BR
for application to bearing housing.
Fig. 3
Dimension code
Type code
Allowable running speed
The allowable running speed for Type WR for shaft
application is as described in applicable Dimensions
Table. This means the running speed when snap ring
begins to get loose with opening of its cut ends.
Fig. 1 WR snap ring
Mounting relation
It is recommended to insert a spacer between snap ring
and cage for guiding the cage in axial direction. On
occasion, snap ring is difficult to remove, but limited to a
portion in which a pull-out
tool can not be inserted easily. In such a case, it is
necessary to consider the use of general snap rings
specified in JIS B 2804 (C-type snap rings) or B 2806 (Ctype
concentric snap rings).
Fig. 2 BR snap ring
Table 1 Cut section angle of snap ring ()
Type Nominal number Cut section angle()
Type WR WR4WR5
40
Type WR6 up to
60
Type BR
All nominal numbers
90
B-226