Slewing ring bearings have been in use for many years; however, lubrication can be a challenge. This is because the stop/start motion of the slewing disrupts the necessary oil build-up. A typical way to overcome this problem is to pump lubricant into the bearing to assure consistent coverage. A better way is to use lubrication-free polymer slewing ring bearings, which are maintenance free and particularly wear resistant.
igus has produced a short video that shows the insides of its iglidur PRT slewing ring bearings and how they are made. The radially and axially acting sliding elements between the inner and outer rings are made of an iglidur material. This tribopolymer enables dry operation, specifically without the need for lubrication, with low coefficients of friction and a low stick-slip effect. In addition, both FDA- and ESD-compliant variants are available. For underwater applications or high-temperature applications up to 180degC, iglidur H1 sliding elements are used instead.
Polymer slewing ring bearings are suitable for a wide spectrum of applications, wherever high cycle rates and loads are key requirements. They come in a range of sizes with inner diameters from 20mm to 300mm and many assorted designs, from lightweight plastic versions and driven slewing ring bearings, to split bearings for difficult installation situations and toothed slewing ring bearings. For confined spaces and medium load applications, such as automation or stage technology, an ultra-low-profile version is available.
igus slewing ring bearings have been rigorously tried and tested out in the field and in-house, at one of the largest test laboratories in the industry. And, to ease the selection process, the data collected from the tens of thousands of continuous tests is incorporated in the online iglidur PRT slewing ring bearing configurator, which is used to calculate the predicted service life in almost any given application.