T-132
Table 15.1 contains the ranges of allowable pitch errors of spur gears and helical
gears for each precision grade, as specified in JIS B 1702-1976.
Table 15-1 The Allowable Single Pitch Error, Accumulated Pitch Error
and Normal Pitch Error, mm
In the above table, W and W' are the tolerance units defined as:
__
W =
3
Ö
d + 0.65m (mm)
(15-1)
W' = 0.56 W + 0.25m (mm)
(15-2)
The value of allowable pitch variation error is k times the single pitch error. Table 15-2
expresses the formula of the allowable pitch variation error.
Table 15-2 The Allowable Pitch Variation Error, mm
Single Pitch Error
fpt
Accumulated Pitch Error
Fp
Normal Pitch Error
fpb
Grade
JIS 0
1
2
3
4
5
6
7
8
0.5W
+ 1.4
0.71W
+ 2.0
1.0W
+ 2.8
1.4W
+ 4.0
2.0W
+ 5.6
2.8W
+ 8.0
4.0W
+ 11.2
8.0W
+ 22.4
16.0W
+ 45.0
2.0W + 5.6
2.8W + 8.0
4.0W + 11.2
5.6W + 16.0
8.0W + 22.4
11.2W + 31.5
16.0W + 45.0
32.0W + 90.0
64.0W + 180.0
0.9W' + 1.4
1.25W' + 2.0
1.80W' + 2.8
2.5W' + 4.0
4.0W' + 6.3
6.3W' + 10.0
10.0W' + 16.0
20.0W' + 32.0
40.0W' + 64.0
less than 5
5 or more, but less than 10
10 or more, but less than 20
20 or more, but less than 30
30 or more, but less than 50
50 or more, but less than 70
70 or more, but less than 100
100 or more, but less than 150
more than 150
Single Pitch Error, fpt
1.00fpt
1.06fpt
1.12fpt
1.18fpt
1.25fpt
1.32fpt
1.40fpt
1.50fpt
1.60fpt
Pitch Variation Error, fpu
