KEVOS® MAKEOS · Gears

Gear Tooth Forces

What tangential, radial and axial forces does this gear mesh put on the shafts?

Tangential, radial (separating) and axial (thrust) tooth forces of a spur or helical gear from power, speed and pitch diameter, for shaft and bearing loads.

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How this tool works

Inputs, units and where to find them

InputUnitTypical source
Power transmittedkWPower through the mesh (motor power × any upstream efficiency).
Speed of this gearrpmSpeed of the gear whose pitch diameter is entered.
Pitch diameter of this gearmmPitch diameter of the same gear.
Normal pressure angle°Normal pressure angle.
Helix angle (0 = spur)°Helix angle; 0 for spur gears.

Method and formulas

  1. T = 9549 × P ÷ n (N·m); Ft = 2T ÷ d.
  2. Radial Fr = Ft tan αn ÷ cos β; axial Fa = Ft tan β.
  3. Total F = √(Ft² + Fr² + Fa²); pitch-line velocity = π d n ÷ 60 000.
  4. Example: 15 kW at 1450 rpm on an 80 mm gear gives Ft = 2,469.6 N and Fr = 898.88 N.

Limitations

  • Friction and dynamic loads are not included; apply application and dynamic factors from your rating method.
  • Example values are illustrations. Replace them with values for your actual task.

Typical uses

  • Find bearing loads from a gear mesh
  • Size shafts carrying gears
  • Check the thrust a helical gear puts on its bearings

Who it is for

  • Gear designers
  • Machinists
  • Maintenance engineers

What you get

  • Torque
  • Tangential, radial and axial force
  • Total tooth force
  • Pitch-line velocity

Interpreting the result

  • Use the forces with the gear position on the shaft to find bearing reactions.

References

  • Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 2131–2160, 2195–2200. Topic reference; no source tables or recommended settings are reproduced.

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Open the Gear Tooth Forces calculator