Page 42 - needle bearings

Shaft and Housing Design
Bearing Fits
NTN
NTN

(2) Outer ring
Similarly to Para. 7.1(1) "Inner Ring", good care 7.2 Bearing fitting dimensions
exercised of the shoulder profile of bearing housing for The respective shoulder heights "h" of shaft and
fixing outer ring in axial direction. housing are designed larger than the maximum chamfer
Figs. 7.9 and 7.10 illustrate the methods of fixing outer dimension rs max for bearing so the bearing end face
ring in axial direction. comes in contact with the flat zone. And the corner
NTN housing snap ring BR type (Refer to Dimensions roundness "ras" is designed smaller than the minimum
Table on page B-229) can be used for fixing outer ring in chamfer dimension "rs" of bearing so as not to interfere
axial direction. NTN BR type snap rings are designed to with the bearing. Generally the radius of shaft and
the dimensions adaptable to the needle roller bearings housing corner roundness shown in Table 7.1 is used as
with low section height. However, commercially available the shoulder heights of shaft and housing.
snap rings conforming to JIS standard as applicable can The dimensions of the shafts and housings related to
also be used for the same bearings with adequately high bearing installation are as described in the dimensions
section height. 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 0.15 0.6 rs min
ras max h
0.2 0.2 0.8
0.3 0.3 1
rs min
Fig. 7.9 Outer ring fixing by lid 0.6 0.6 2
ras max h
1 1 2.5
rs min
1.1 1 3.25
rs min
1.5 1.5 4
2 2 4.5
2.1 2 5.5
2.5 2 6
3 2.5 6.5
4 3 8

Table 7.2 Relief grinding dimension for shaft and housing corners
Unit mm
rs min b t rcs
b
1 2 0.2 1.3 rs min
1.1 2.4 0.3 1.5 t
rcs
1.5 3.2 0.4 2
2 4 0.5 2.5
rcs
2.1 4 0.5 2.5
t
3 3.7 0.5 3 rs min
b
4 5.9 0.5 4

Fig. 7.10 Outer ring fixing by snap ring

A-38