S and W gear units

The gearing in helical-worm and SPIROPLAN® gear units produces a high proportion of sliding friction. As a result, these gear units have higher tooth friction losses and thus lower efficiencies than R, F or K gear units.

Other factors influencing the efficiency:

  • Gear ratio of the helical-worm or SPIROPLAN® stage
  • Input speed
  • Ambient temperature

Helical-worm gear units from SEW-EURODRIVE are helical gear/worm combinations that are significantly more efficient than plain helical-worm gear units.

The efficiency may be η < 0.5 at very high gear ratios of the helical-worm stage.