Micro Harmonic Drive — The principle of operation

 

 

 

 

A movie about the principle of operation you can watch at the website of the Harmonic Drive AG.

 

 

Absolutely unique

The Micro Harmonic Drive Gear is based on a unique principle that consequently exploits the elasticity of the metallic components.

 

Wave Generator in operation

When used as a speed reducer, the Wave Generator's sun gear serves as the drive (input) element. The Flexspline expands as the Wave Generator's planetary gears move around the sun gear. At the same time, the Flexspline's outer teeth engage with the Circular Spline and the Dynamic Spline. As the sun gear turns, the planetary gears orbit in the Wave Generator — the large elliptic axis shifts and thus also the position of tooth engagement.

 

Dynamic Spline as output

Since the Flexspline has two teeth less than the Circular Spline, after the Wave Generator has turned through half a revolution the relative motion of the Flexspline with respect to Circular Spline has regressed by one tooth; after a full revolution of the Wave Generator this relative motion has caused a shift amounting to two teeth. By fixing the Circular Spline in place, the Flexspline rotates in the opposite direction of the sun gear. The Dynamic Spline rotates in unison with the Flexspline, i.e. the same direction and speed, and is used in reduction mode as the output element.

 

 

 

Tooth profiles

 

Individually adapted

The described gear component sets and gearboxes can be supplied with either one of two different tooth profiles:
IH- or P-tooth profile. The Micro Harmonic Drive is delivered standard with IH-tooth profile. Micromotion GmbH has developed new P-tooth profile for micro gears intended for applications that make particularly high demands on torque capacity and torsional stiffness.

 

P-tooth profile — 200 % stronger and stiffer

In comparison to conventional tooth profile, the new P-tooth profile achieve an increase of up to 200 % for both transmitted torque as well as for torsion strength. A distinct performance boost based on optimised tooth profiles.

 

Impressive results in practice

For customer applications this performance boost means that either greater loads can be moved or higher acceleration can be attained to obtain shorter cycle times and higher productivity.