Page 1683 - MiSUMi 2025

[Technical Data]
Timing Pulleys Excerpts from JIS B 1856 (1993)

1. Dimensions of the Rack for the Cutter and the Tolerances

Pt
A A The pulley should have involute teeth, which
are created and shaped by the cutter. The
dimensions of the rack for the cutter and the
tolerances as determined by analyzing the
a
shape of the rack with a projector, shape
hr r2 measuring instrument or the like, should be
agreed with the relevant figures in the table
b g r1 below.

Unit: mm
Number of Teeth of hr bg 2a (1)
Type the Pulley Pt A ＋0.05 ＋0.05 r1 r2
Z Ú0.12 0 0 Ú0.03 Ú0.03 (Reference)
10≤Z≤23 28B 0.61
MXL 2.032Ú0.008 0.64 0.30 0.23 0.508
24≤Z 20B 0.67
XL 10≤Z 5.080Ú0.010 25B 1.40 1.27 0.61 0.61 0.508
Note ( ) : a is a measurement indicating the position corresponding to the pitch line (Centerline of the Core Line of the Belt) of the belt corresponding to the
1
shape of the rack for the cutter.
2. Tolerance of Adjacent Pitch Error and Cumulative Pitch Error Unit: mm 4. Tolerance of Addendum Circle Diameter Unit: mm
Addendum Circle Diameter of Pulley Allowable Value Addendum Circle Diameter of Pulley Tolerance
P.D. Tolerance of Adjacent Pitch Error Accumulated Pitch Error P.D.
5.96≤d0≤ 25.40 0.03 0.05 5.96≤d0≤ 25.40 ＋0.05
0
25.40<d0≤ 50.80 0.03 0.08 25.40<d0≤ 50.80 ＋0.08
0
50.80<d0≤101.60 0.03 0.10 50.80<d0≤101.60 ＋0.10
0
101.60<d0≤177.80 0.05 0.13 101.60<d0≤177.80 ＋0.13
0
177.80<d0≤304.80 0.05 0.15 177.80<d0≤304.80 ＋0.15
0
304.80<d0≤508.00 0.08 0.18 304.80<d0≤508.00 ＋0.18
0
508.00<d0≤762.00 0.08 0.20 508.00<d0≤762.00 ＋0.20
0
762.00<d0≤967.16 0.08 0.23 762.00<d0≤967.16 ＋0.23
0
3. Tolerance of Side Deflection Unit: mm 5. Tolerance of Circumferential Deflection of Addendum Circle Unit: mm
Addendum Circle Diameter of Pulley Tolerance of Deflection(TIR) ( 2 ) Addendum Circle Diameter of Pulley Tolerance of Circumferential
P.D. P.D. Deflection
5.96≤d0≤101.60 0.10 5.96≤d0≤203.20 0.13
101.60<d0≤254.00 Addendum Circle Dia. d0×0.001 203.20<d0≤967.16 0.13+〔(Addendum Circle Dia. d0-203.20)×0.0005〕
254.00<d0≤967.16 0.25+〔(Addendum Circle Dia. d0-254.00)×0.0005〕
Note ( ) : TIR is an abbreviation for Total Indicator Reading and 6. Tolerance of Cylindricity and Parallelism Unit: mm
2
refers to the difference between the max. deflection
reading and the min.deflection reading. Nominal Widths of Pulley Cylindricity Tolerance Parallelism Tolerance
025～050 0.01 0.03
075～150 0.02
200·300 0.04 0.04
400·500 0.06 0.05

B-038