To generate accurate movement along the 5th robot axis, igus developed new types of strain wave gears based on its tribo-polymer technology. Using lubrication-free high-performance polymers such as iglidur, the strain wave gears are extremely compact and light, but also require very little maintenance and have long service life. The main components of the gearbox include a wave generator and a flexible ring with outer drive teeth, as well as an outer ring, fixed in place in the housing and a rotary power take-off element with inner drive teeth.
The wave generator has an elliptical shape; therefore, the surrounding flexible ring also assumes this shape. The drive teeth of the flexible ring engage at two places in the inner drive teeth of the outer ring and power take-off element. The flexible ring is only moved two teeth further per rotation when the wave generator is rotated. The current version is based on the installation size Nema 17 for direct connection to a stepper motor and can easily be adapted to other types of motor.