The German engineering plastics specialist igus says that design of a new range of pillow block bearings is based on the structure of trees. Flattened radii, like those found at a tree’s base, ensure maximum strength against mechanical stresses. According to the company, the lubrication- and maintenance-free plastic housings are a real alternative to cast-housing bearings.

Cast housings with metal ball bearings can suffer in dusty, wet and dirty environments. Heavy contamination and a lack of lubrication are responsible for 80% of premature bearing failures in these applications, according to igus. And there is a risk of metal corrosion.

The polymer pillow block bearings with lubricant-free, chemical-resistant bearing inserts made of high-performance plastic are available in 20, 25 and 30mm sizes, allowing one-to-one replacements. There are also two- and four-hole flange stops in 20, 30 and 40mm versions.

Two design techniques ensure that the plastic pillow block bearings are robust. First, fibres and fillers strengthen the plastic to withstand high surface pressures and edge loads, even under continuous loads. And second, the designers have optimised the shape of the housing supports (collars) and avoided constant radii to distribute the forces more evenly, making the bearings highly resilient.

The absence of lubricants reduces the need for maintenance and cleaning, and improves environmental protection by eliminating leakages.

Igus has made other additions to its igubal range, including three bearing inserts for imperial measurements, with 1, 1.5 and 2 inch inner diameters. The price of the FDA-compliant iglidur A350 plain bearings will fall by around 50% because igus is no longer relying solely on a turning process to manufacture them from semi-finished products, but now also uses more cost-effective, high-volume injection moulding.