Date Published: Feb 10, 2023

Why do bearing design engineers prefer lightweight slewing rings in challenging motion control applications, especially the ones related to the aerospace and defence sectors? Simply put, lightweight slewing rings have demonstrated exceptional capabilities in the most difficult and high-tech applications where optimal mechanical performance, absolute precision, and superior corrosion resistance are necessary. The reasons are more thoroughly examined and discussed by Karl Brundell, the Managing Director of Carter Manufacturing Ltd. – an industry-leading precision bearing specialist, situated in Abingdon.


In certain cases, the data speaks for itself. One of our most durable and lightweight aluminium slewing bearings, for instance, was recently chosen for military turret mounting in a defence-related application. Despite having a run-out calculated in microns, the turret has a diameter of more than two meters. Simply said, a slewing ring or bearing enables design teams to substitute a single item for a pair of bearings, hence lowering the number of parts, difficulty, weight, and expense. Carter Manufacturing Ltd. has worked on a variety of slewing bearing applications, such as Cardiovascular equipment and CT scanners for medical use, radar gimbals and propulsion systems for spacecraft, weapon systems and helicopter seat mounts for aerospace, and other high-precision military systems such as gun turrets, surveillance systems and robots.


Carter Bearings = Superior Design + Outstanding Precision


While several styles of slewing bearings are available for motion control applications that are not as demanding, there are comparatively fewer options for usage in high-technology applications. Examples of such systems are satellites, AFVs (armoured fighting vehicles), ultra-high vacuum conditions, or military-specific tracking arrangements that call for substantially greater standards of precision, weight reduction, and corrosion safety. In the instance of the aluminium slewing ring, previously stated, this extraordinary precision has been successfully attained by using an inventive split thin section bearing design. It includes a split inner and outer ring that enables the shaft and housing fits to decide the bearing preload, which facilitates the placement of preload settings during the design stage of the application. Key advantages include significant cost savings by removing the need to request particular preloads to be set into the bearing during the factory assembly stage, as well as radically enhanced corrosion resistance due to the use of stainless steel components in some portions of the design.


When a slewing bearing is under heavy load, its rolling components are designed to move in a way that counteracts any existing overrunning loads that are present in the motion control application. The designers of military land, sea, and aerial equipment have found this to be crucial as smaller-sized boats, cars, and unmanned aerial vehicles (UAVs) are harder to spot or follow when used in real operations. Furthermore, lightweight slewing bearings can also be beneficially utilised in applications where a connected drive system or gear ring is required.