Selecting a Motor: Formulas for Calculating Load Torque TL [N·m] by Drive Mechanism
Formula for Load Torque
Ball Screw Drive

Pulley Drive

Wire and Belt Drive, Rack-and-Pinion Drive

Actual Measurement Method

- F
- Operation Direction Load [N]
- F0
- Preload [N] (≒ 1/3F)
- µ0
- Internal Friction Coefficient of Preload Nut (0.1~0.3)
- η
- Efficiency (0.85~0.95)
- i
- Speed Reduction Ratio (This is the speed reduction ratio of the mechanism and not the gear ratio of the Oriental Motor's gearhead)
- PB
- Ball Screw Lead [m/rev]
- FA
- External Force [N]
- FB
- Force When Main Shaft Begins to Rotate [N] (FB = Spring Balance Value [kg] × g [m/s2])
- m
- Total Mass of Table and Load [kg]
- µ
- Friction Coefficient of Sliding Surface
- θ
- Inclination Angle [˚]
- D
- Final Pulley Diameter [m]
- g
- Gravitational Acceleration [m/s2] (9.807)