Page 67 - needle bearings

Needle roller and cage assemblies
NTN

Inter-roller diameter deviation of needle rollers Shaft and housing specifications
Inter-roller diameter deviation of needle rollers which Where a shaft and a housing are used as the direct
are built in one cage is within 2um. The respective raceway surface, the raceway surface must meet the
specified diameter tolerances for built-in needle rollers specifications described in Table 3.
are identified by identification colors on the package label,
as shown in Table 1.
Table 3 Shaft and housing specifications
The standard identification colors marked on each label
are red, dark blue, blue, black and white, unless Characteristics Shaft Housing
otherwise specially indicated. Roundness (max) IT3 IT4
Where two or more bearings are used in tandem, those
Cylindricality (max) IT3 IT4
of same identification color must be used for equal
distribution of bearing load. Surface roughness (max) Refer to Table 7.4 on page A-39.
Surface hardness HRC58ʙ64
Depth of hardened layer (min) Refer to formula (7.1) on page A-39
Table 1 Color identification of diameter tolerances for needle roller bearings
Identification color on label Diameter tolerance Жm Classification
Red 0ʙʵ 2
Dark blue ʵ1ʙʵ 3 Bearing installation related dimensions
Blue ʵ2ʙʵ 4 Standard
The tolerances for the nominal dimension "Bc" of cage
Black ʵ3ʙʵ 5
specified in Table 4 are recommended as the guide width
White ʵ4ʙʵ 6
b of cage.
Gray ʵ5ʙʵ 7
Green ʵ6ʙʵ 8
Semi-standard Table 4 Guide width tolerances
Brown ʵ7ʙʵ 9 Unit : mm
Tolerances for guide width b
Yellow ʵ8ʙʵ10
Classification
Single row Double row
Metric system Bc ʴ0.2 Bc ʴ0.3
ʴ0.1
ɹ0
Inch system Bc ʴ0.4 Bc ʴ0.5
Radial Clearance ʴ0.2 ʴ0.3
When a shaft and a housing are used as the direct
raceway surface, the radial clearance is determined by
the shaft diameter and the housing hole dimension.
Where the diameter tolerances for needle rollers are b
standard (tolerances color-identified in red, dark blue, Bc
blue, black, white), the shaft diameters and housing hole
dimensions shown in Table 2 are used.

Table 2 Recommended fits
Shaft diameter mm ʙ80 80ʙ140 140ʙ
Shaft guide
Smaller than ordinary clearance j5/G6 h5/G6 h5/G6
Radial Ordinary clearance b
clearance h5/G6 g5/G6 f5/H6
Larger than ordinary clearance g6/G6 f6/G6 f6/G6 Bc

Housing guide
Fig. 1

B-5