Torque Rating Synchronous Timing Belt Equation and Calculator

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Torque Rating Synchronous Timing Belt Equation and Calculator

Belt Drive Design and Engineering
Mechanical Gear Design and Engineering

Synchronous Timing Belt Torque Rating Equation and Calculator per. ANSI RMA IP-24, ISO 5299 and IS 9804 for small pitch MXL section belts

Use horsepower rating design formulas for synchronous belts, other than the MLX sections:
Synchronous Timing Belt Horsepower Rating Equation and Calculator per. ANSI RMA IP-24

Torque Ratings: It is customary to use torque load requirements rather than horsepower load when designing drives using the small pitch MXL section belts. These belts operate on small diameters resulting in relatively low belt speeds, so torque is essentially constant for all rpm. The torque rating formulas for MXL sections are:

Q_r = K_z [ d ( 1.13 - 1.38 x 10^-3 d²) ] For belt width = 0.12 in.

Q_r = K_z [ d ( 1.88 - 2.30 x 10^-3 d²) ] For belt width = 0.19 in.

Q_r = K_z [ d ( 2.63 - 3.21 x 10^-3 d²) ] For belt width = 0.25 in.

Where:

Q_r = maximum torque rating (lbf-in.) for a belt of specified width having six or more teeth in mesh and a pulley surface speed of 6500 fpm or less.
K_z = Torque rating multiplier (see Table Below). Torque ratings for drives with less than six teeth in mesh must be corrected as shown.
d = pitch diameter of smaller pulley in belt mechanism, inch.

Teeth in Mesh (N)	Factor K_z
6 or more	1.00
5	0.80
4	0.60
3	0.40
2	0.20

References:

ANSI / RMA IP-24
ISO 5299
IS 9804.