The switch from traditional metal gearboxes to Apiro drygear gearboxes, which feature high-performance plastic worm gears, offers numerous advantages: lower costs, reduced weight and no lubrication required. For particularly demanding applications, however, many designers have so far been cautious about adopting plastic solutions, fearing that they would not be sufficiently resistant to impact and mechanical stress. To meet this need, igus has developed drygear Apiro HD, a hybrid solution that combines the advantages of both materials. The worm gear continues to be made of tribopolymers, while the die-cast zinc-based alloy housing ensures the required robustness even under the most demanding operating conditions.

Thanks to this solution, designers can use couplings, drive units and gearboxes – many of them made of high-performance plastic – to develop lightweight, cost-effective and lubrication-free automation systems. Typical applications include pushers for the material handling sector and format change systems for the food and beverage industry. “However, some designers were reluctant to adopt this technology, fearing that in the most demanding applications the gearboxes might be damaged by impacts caused by the goods being transported”, explains Giulio Ferrante, country manager at igus Italia and head of the dry-tech division. “That is why we have developed a zinc die-cast housing for one of our most popular models, our Apiro worm gear reducer, making it suitable even for the most demanding operating conditions”.

Load capacity up to 70 kg

The new die-cast housing made from zinc-based alloys has increased the gearbox’s load-bearing capacity. The stiffer material allows for a static load of up to 70 kg and a dynamic load on the gearbox of up to 25 kg.

‘With this solution, we are meeting the growing demands of format-change applications, whilst ensuring the mechanism is protected from impacts,’ adds Ferrante. Die-casting is also more cost-effective than aluminium or steel die-casting. The material is characterised by high mechanical strength and corrosion resistance. Thanks to their low melting point, zinc-based alloys are easy to machine and allow for particularly precise and dimensionally accurate production. This reduces both energy consumption and the effort required for post-production. Even in the new hybrid version, the plastic worm gear with a 4:1 ratio continues to operate without lubrication and is therefore maintenance-free. “With Apiro HD, we are meeting the needs of designers by offering a hybrid model that combines robustness with cost-effectiveness”, concludes Ferrante.