Needle Roller Bearings - Ntn-snr.com

Shaft Bearing and Fits Housing Design
NTN
(2) Outer ring
Similarly to Para. 7.1(1) "Inner Ring", good care
exercised of the shoulder profile of bearing housing for
fixing outer ring in axial direction.
Figs. 7.9 and 7.10 illustrate the methods of fixing outer
ring in axial direction.
NTN housing snap ring BR type (Refer to Dimensions
Table on page B-229) can be used for fixing outer ring in
axial direction. NTN BR type snap rings are designed to
the dimensions adaptable to the needle roller bearings
with low section height. However, commercially available
snap rings conforming to JIS standard as applicable can
also be used for the same bearings with adequately high
section height.
7.2 Bearing fitting dimensions
The respective shoulder heights "h" of shaft and
housing are designed larger than the maximum chamfer
dimension rs max for bearing so the bearing end face
comes in contact with the flat zone. And the corner
roundness "ras" is designed smaller than the minimum
chamfer dimension "rs" of bearing so as not to interfere
with the bearing. Generally the radius of shaft and
housing corner roundness shown in Table 7.1 is used as
the shoulder heights of shaft and housing.
The dimensions of the shafts and housings related to
bearing installation are as described in the dimensions
table for each bearing type. The shoulder diameter shown
in this table means the effective shoulder diameter which
comes in contact with the side face of bearing excluding
the chamfered portion of shoulder.
When the fitting surface of shaft or housing is finished
by grinding, the shoulder corner must be provided with a
relief. This relief dimension is as shown in Table 7.2.
Table 7.1 Radius of shaft /housing corner roundness and
shoulder height
Unit mm
rs min ras max h (min)
0.15
0.2
0.3
0.15
0.2
0.3
0.6
0.8
1
rs min
ras max
rs min
h
Fig. 7.9 Outer ring fixing by lid
0.6
1
1.1
1.5
2
2.1
0.6
1
1
1.5
2
2
2
2.5
3.25
4
4.5
5.5
ras max
rs min
rs min
h
2.5
3
4
2
2.5
3
6
6.5
8
Table 7.2 Relief grinding dimension for shaft and housing corners
Unit mm
rsmin b t rcs
1
1.1
1.5
2
2.4
3.2
0.2
0.3
0.4
1.3
1.5
2
t
b
rs min
rcs
2
2.1
3
4
4
4
3.7
5.9
0.5
0.5
0.5
0.5
2.5
2.5
3
4
t
rcs
b
rs min
Fig. 7.10 Outer ring fixing by snap ring
A-38