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.
Accuracy, Design sturdiness, and Robustness
Slewing bearings are offered in a wide array of kinds and designs, but the three most frequently used types are plain, flanged, and geared. To achieve absolute design accuracy and sturdiness, the slewing bearing is typically fastened to the required faces, utilising holes in both the inner and outer rings. All of these design elements are crucial, particularly for high-accuracy applications like target trackers, radars, or AFV turrets. Depending on the lateral or longitudinal design load parameters that have been defined or are anticipated, alternative mounting techniques may also be used. Slewing bearings have a wide range of applications, which is also reflected in both their internal raceway designs and geometry.
Many distinct internal and external types of slewing bearings can be used in high-tech applications, particularly in the aerospace, defence, nuclear and cryogenic industries. Engineering professionals have a variety of options to choose from, once the loads are projected for each application. Examples include single or double ball design, single or double roller design, triple rollers, cross rollers or ball/needle/roller mix with either wire-race inserts or split design. This indicates that Carter Manufacturing Ltd. may undertake numerous options to customise a slewing bearing response to a particular application, whether it is intended to support a scanner, weighing 200gm and spinning at 200deg/sec, or a telescope, weighing 12 tonnes that takes up to 20 hours to finish a complete revolution.
The selection of Materials and the significance of Lubrication and Sealing
There are several intriguing material options available for ultra-high vacuum applications, such as aluminium, which can be selected for weight-sensitive applications needing to be both incredibly compact and extremely strong. While design engineers may be dedicated to producing illustrations that adhere to the necessary standards, it's occasionally left to others to take sealing and lubrication into consideration, which is a crucial component of bearing performance and equally applies to slewing bearings.
For instance, specific seals and lubrication are required for the slewing bearings used in harsh environments, on spaceships, in ultra-high vacuums, or applications involving extreme temperatures. There are numerous basic solutions available for common manufacturing applications, but for high-end purposes, Carter Manufacturing Ltd. have been involved in some noteworthy industrial and scientific projects, for over two decades. Consequently, this has led to the creation of customised seals and cutting-edge lubricants that have changed the game, industry-wide. Furthermore, the broad range of aerospace, defence, and other high-tech applications, for which lightweight slew rings are currently being utilised, has underlined the advantages of Carter's in-house and well-respected advanced modelling tools, CAM, CAD, and FEA facility.
Precision, Durability, Lightness, and Resistance to Corrosion
The majority of Carter Manufacturing projects call for bearings with extremely high customer specifications and comparatively short production runs. Precision, durability, lightweight, and resistance to corrosion are regarded as their essential qualities. Our facilities give designers the freedom to create specialised bearings, capture the crucial data they need, and collaborate with us to fine-tune the ideal materials and bearing design choices prior to producing functional prototypes. When we first converse about an application, it is crucial to establish certain parameters; such as revolving speed, platform stiffness, flexing loads, vertical play, mounting alternatives, ingress security, corrosion safety, and ease of rotary motion. The design performance targets declared in the client’s specifications must also be met, the majority of which typically entail hostile situations of some kind. While it is critical to ascertain the overturning moment load, it is equally essential to keep other significant bearing design elements in check including material choice, physical size (both in terms of thickness and diameter), and load capacity.
The lightweight slewing bearing rings by Carter Manufacturing Ltd. can be differentiated based on the rolling elements, constructed from several diverse base materials, including ceramics, stainless steel, and chromium steel, to accommodate a varied range of customer applications. A few prominent examples of these applications comprise surveillance cameras, spaceships, helicopter seating and hybrid automobiles.
Along with a wide variety of standard slewing rings, a substantial range of external mounting alternatives are also offered to accommodate various designs and applications, by enabling the attachment of special ancillaries onto them. For instance, specialised slewing bearings can effortlessly be mounted to multiple monitoring devices like position indicators, sensors, rotary encoders and vibration analysis senders.