T-136
Table 15-5 Equations for Allowable Single Pitch Error, Accumulated Pitch Error
and Pitch Cone Runout Error, mm
The equations of allowable pitch variations are in Table 15-6.
Table 15-6 The Formula of Allowable Pitch Variation Error (mm)
Besides the above errors, there are seven specifications for bevel gear blank
dimensions and angles, plus an eighth that concerns the cut gear set:
1. The tolerance of the blank outside diameter and the crown to back surface distance.
2. The tolerance of the outer cone angle of the gear blank.
3. The tolerance of the cone surface runout of the gear blank.
4. The tolerance of the side surface runout of the gear blank.
5. The feeler gauge size to check the flatness of blank back surface.
6. The tolerance of the shaft runout of the gear blank.
7. The tolerance of the shaft bore dimension deviation of the gear blank.
8. The contact band of the tooth mesh.
Item 8 relates to cutting of the two mating gears' teeth. The meshing tooth contact
area must be full and even across the profiles. This is an important criterion that supersedes
all other blank requirements.
JIS 0
1
2
3
4
5
6
7
8
Single Pitch Error
fpf
Grade
0.4W + 2.65
0.63W + 5.0
1.0W + 9.5
1.6W + 18.0
2.5W + 33.5
4.0W + 63.0
6.3W + 118.0
––
––
Runout Error of Pitch Cone
Fr
Accumulated Pitch Error
Fp
1.6W + 10.6
2.5W + 20.0
4.0W + 38.0
6.4W + 72.0
10.0W + 134.0
––
––
––
––
__
2.36Öd
__
3.6Öd
__
5.3Öd
__
8.0Öd
__
12.0Öd
__
18.0Öd
__
27.0Öd
__
60.0Öd
__
130.0Öd
__
where:
W = Tolerance unit =
3
Ö
d + 0.65m (mm),
d
= Pitch diameter (mm)
Single Pitch Error, fpt
Pitch Variation Error, fpu
Less than 70
70 or more, but less than 100
100 or more, but less than 150
More than 150
1.3fpt
1.4fpt
1.5fpt
1.6fpt
