Page 285 - needle bearings

Needle rollers
NTN

The maximum value of housing bore diameter (D)
Application of needle rollers required to retain needle rollers in a housing by a
When composing a full-complement roller type needle keystone can be determined from the minimum diameter
roller bearing using standard needle rollers, shaft value (Dw min) of the roller and the number of rollers using
diameter (d), housing hole diameter (D), circumferential formula (4). The coefficient K to be used in that time is as
clearance (∆C) shown in Table 4.
and radial clearance (∆r) must be determined
DʹK ŋDw min mm (max.) ⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯(4)
respectively. These can be calculated as follows from
needle roller diameter (Dw) and number of rollers (Z).
(Refer to Fig. 2)
Determine the minimum value of circumferential
clearance (∆C) using formula (1). And select radial Number of rollers Z
Dw
clearance (∆r) according to applicable shaft diameter and
operating conditions, in reference to Table 5.1, as the
guideline, of 5.1 “Bearing Radial Clearance” (page A-
30). In general, full-complement roller type bearing needs
radial clearance larger than that in needle roller and cage
assembly type roller bearing. D
∆Cʹ (0.005ʙ0.020) ʷZ mm (minimum value) (1)
Then, determine the minimum value of housing bore
diameter (D) and the maximum value of shaft diameter
(d) using the formulas (2) and (3).
]
[ 1 ∆C Fig. 3
Dʹ ʵʵʵʵʵʵʵʵʵʵʴ1 ŋ Dw ʴʵʵʵʵ NN (minimum value)
К
К
sin (ʵʵʵ)
Z ⋯⋯⋯⋯⋯(2)
Table 4 Coefficient K value
dʹD ʵ 2Dw ʵ ∆r mm (maximum value)⋯⋯⋯(3)
Z K Z K
8 3.6763333 17 6.4536463
9 3.9709394 18 6.7689303
10 4.2727719 19 7.0846088
Dw Number of rollers Z
11 4.5789545 20 7.4006100
∆C 12 4.8879667 21 7.7168786
13 5.1989251 22 8.0333713
∆r
14 5.5112799 23 8.3500534
15 5.8246707 24 8.6668970
16 6.1388508 25 8.9838796
d D

Fig. 2

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