How polymer strain wave gears complement low-cost automation

Using iglidur high-performance plastics means that strain wave gearboxes from igus do not have to be lubricated like their metallic counterparts. Friction and wear are also reduced by the dry-running tribopolymers. Through active research and further development of the wave gear units, especially in the latest generation, igus has minimised backlash, ensuring precise adjustment with incredible 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. Because 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.

A typical application for the shaft gear is as the final axis of a robotic arm, linear robot and delta robots before the various gripper systems are added. At this point it takes over the task of gripping and precisely positioning objects that are not rotationally symmetrical. The current development is based on the NEMA 17 size for direct connection to a stepper motor and can be easily adapted to other motor types.

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 1 million cycles at a load of 1.5Nm and a speed of 6rpm.

Follow the links to watch the video, which shows how the new strain wave gear is built and works, and for more information about igus strain wave gears.