Lightweight strain wave gears
Published: 19 June 2020 - Rachael Morling
iglidur high-performance plastics means that strain wave gearboxes from igus do not have to be lubricated like their metallic counterparts, the company explains. Friction and wear are also reduced by the dry running tribopolymers. With the units, igus has minimised backlash, ensuring precise adjustment with reliability.
The main components of the gearboxes comprise a shaft generator and flex ring with external teeth, as well as an outer ring fixed to the housing and a rotating output element with internal gear. The wave generator has an elliptical shape, which is transferred to the surrounding flexible ring. The teeth of the flex ring engage in the internal teeth of the outer ring and output element at two points. Since the outer ring has two teeth more than the other components, the flex ring is only moved forward by two teeth per revolution when the wave generator rotates.
The load capacity of the shaft gears was determined in in-house tests. For example, with a gear ratio of 28:1, the gear unit shows a service life of one million cycles at a load of 1.5Nm and a speed of 6rpm.