Reliable movement with igubal pillow block bearings in solar trackers

Each module of the tracker system can consist of 9 or 18 units of 540-560 watt panels, which have an output of 5 or 10 kW respectively. To support the horizontal square profiles that carry the solar panels, the designers were looking for suitable bearings (two for the 9-panel units and three for the 18-panel units).

The environment is a challenge for the bearing, as the system is exposed to high temperatures in summer, the effects of wind and rain as well as dirt and dust. Withstanding these conditions was one of numerous other requirements for the bearings: they had to withstand the high load of the entire tracking system - consisting of the panels, their supports and a corresponding counterweight - and at the same time have a low coefficient of friction. They should be spherical bearings that can absorb some axial loads, enable low-noise operation without torque fluctuations and have a service life of 25 years. All this ideally without lubrication and maintenance.

The engineers initially considered lubricated metal and composite plain bearings, but then found the technically best and most cost-effective solution at igus®: igubal® pillow block bearings from the ESTM series, which were specially developed for single-axis solar tracker systems. They consist of a housing made of igumid® G, a particularly robust, long fibre-reinforced polymer, and a very low-friction iglide® J4-spherical ball.

The service life of the bearing reached 72 years at a load of 1.5 tons in the igus® test laboratory, simulated over time. Therefore, igus® guarantees a service life of 25 years. The cost-effective pillow block bearings are UV-resistant, corrosion-free and require no lubrication, which makes them insensitive to dirt and completely maintenance-free. They also enable self-aligning, e.g. for uneven surfaces, and are quick and easy to install thanks to their two-part design. A true "fit-and-forget" solution with which Axiom Research Labs is very satisfied.