Cost-effective Strain Wave Gears thanks to Tribo-Polymers

igus has developed a new range of strain wave gears based on tribo-polymer technology, which make these low-cost, lubrication-free devices and at the same time reduce friction and wear. These strain wave gears have an operating life of one million cycles with a load of 1.5 Nm and a speed of 6 rpm.

In order to generate accurate movement along the 5th robot axis, the motion plastics specialist igus has developed new types of strain wave gears based on its tribo-polymer technology. Due to the use of lubrication-free high-performance polymers, they are not only extremely compact and light but also require very little maintenance and have an especially long service life. The latest generation supplements the gearbox series from igus and is part of the continually growing range of products for Low Cost Automation. Tribo-polymers are used wherever the goal is an improvement of technical performance and a simultaneous reduction of costs. The advantages of tribo-polymers are especially apparent in the case of gearboxes: due to the use of iglidur high-performance polymers, strain wave gears from igus require no additional lubrication, in contrast to metal types of gear. Friction and wear are also improved.

Flexible strain wave gears with high resistance to wear

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 necessary flexibility and high degree of wear resistance are achieved through the use of lubrication-free high-performance igus polymers. 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. As the outer ring has two teeth more than the other components, the flexible ring is only moved two teeth further per rotation when the wave generator is rotated. Along the last axis of an articulated arm, linear robot or delta robot, the strain wave gear can be used before different gripper systems.
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. The load bearing capacity of the strain wave gear has been determined in the test laboratory. With a transmission ratio of 28:1, the gearbox has a service life of one million cycles under a load of 1.5 Nm and at a speed of 6 rpm. As a next step, there are plans to develop a size Nema 23 gearbox.

Cost-effective and long-lasting automation solutions

Like igus worm gears and planetary gears, strain wave gears are also part of the igus Low Cost Automation product range. These products can be used to develop cost-effective and long-lasting automation solutions for small and medium-sized enterprises – such as pick&place tasks. And all this is possible at a very favourable price, whereby the investment often pays for itself within just a few months.