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A Guide to Reali-Slim® Thin Section Bearings
Kaydon Reali-Slim® thin-section bearings are among the most widely used thin-section bearings in the world. Kaydon develops thin-section bearing solutions that reduce weight, save space, reduce friction, increase design flexibility and provide excellent operating accuracy. Kaydon has patented the Thinfinite® Engineering process they developed and used it to manufacture Reali-Slim and Ultra-Slim® bearings. This blog will comprehensively introduce the types, loads, applications and installation of Reali-Slim® thin-section bearings, and provide constructive advice for you to choose appropriate thin-section bearings.
Years ago, in order to help engineers install bearing assemblies into smaller spaces, Kaydon engineers developed a new type of bearing that maintains the same cross-section: Reali-Slim® thin-section bearings. Reali-Slim® bearings save up to 85% space and weight compared to traditional deep groove ball bearings. This result also results in a 40% reduction in system costs. Despite their slim appearance, Reali-Slim® bearings have the load-carrying capacity to handle a variety of applications. Typical applications for Reali-Slim® bearings are robotics. Robot designers are faced with the challenge of maximizing payload and reducing internal space in order to increase robot response and optimize power requirements. Technical designers are specifying Kaydon’s Reali-Slim® thin-section bearings for their demanding applications.
Reali-Slim® Thin Section Bearing Assemblies
Reali-Slim® thin-section bearing assemblies include inner rings, outer rings, rolling elements and cages. Among them, the inner ring and outer ring are the main parts of the thin-section bearing, and the rolling elements roll between the inner and outer rings. The function of the cage is to keep the position of the rolling elements stable and at the same time separate the rolling elements to prevent them from contacting each other. The inner and outer rings are usually made of high-strength stainless steel, high carbon steel or ceramics. Rolling elements are usually made of spherical or cylindrical high-hardness materials, such as ceramics, carbide, etc. Cages are usually made of lightweight materials, such as aluminum alloys, polymers, etc.
Reali-Slim® Thin Section Bearing Series
Kaydon Reali-Slim inch series of thin section bearings includes seven open series and five sealed series with bore diameters ranging from 1.000 inches to 40.000 inches. Their cross-sectional areas range from 0.187 x 0.187 inches to 1.000 x 1.000 inches. Kaydon can also provide internal fittings, lubricants, separators and other features to meet the most demanding application specifications. (For better corrosion resistance, Kaydon stainless steel Reali-Slim or Endura-Slim series bearings are a good option. Endurakote-coated bearings provide corrosion protection equal to or better than AISI 440C stainless steel bearings). Other product variants of Reali-Slim thin section bearings include Reali-Slim MM metric series bearings, ultra-thin section bearings, Reali-Slim TT series slewing support bearings, and BB metric ball bearings. Within these series, you can choose from open thin section bearings (for applications where the bearings are not exposed to harmful particles) and sealed bearings (for applications where the bearings need to be kept clean and well lubricated).
Reali-Slim® thin section bearing loads
Reali-Slim® thin-section bearings support a shaft or housing, allowing it to rotate freely around the shaft. Loads can be applied to bearings from two cardinal directions. There are three main loads to consider when selecting bearings in any engineering application, namely radial, axial (or thrust) and moment loads. Among them, radial load is any force applied perpendicular to the central axis of the object, axial load acts parallel to the central axis of the object, and moment load is applied along the axis of rotation. When these loads are deflected away from the bearing axis (distance St) or the radial plane (distance Sr), moment loads (M) are generated. Reali-Slim bearings are available in various types to accommodate radial, axial and moment loads. Radial ball bearings are not designed for these moment loads, while X-type four-point contact bearings can withstand all three loads.
Reali-Slim thin section bearing type
To support the various loads in an application, Kaydon Reali-Slim bearings are available in three basic types: radial contact (Type C), angular contact (Type A) and four-point contact (Type X). Designers can also choose from a wider range of types to meet load, stiffness and accuracy requirements in the most efficient manner, such as KA, KB, KC and .
C type radial contact bearing
Type C radial contact bearings are a Conrad-type assembly, a single row radial ball bearing design. It is assembled by eccentric displacement of the inner ring within the outer ring, allowing the insertion of approximately 50% full balls. Type C bearings carry primarily radial loads and also allow thrust loads in either direction – often in conjunction with another bearing. But if thrust loads are carried, angular contact bearings should be considered.
A type angular contact bearings
Type A angular contact bearings have a smaller shoulder on the raceway side of the inner or outer ring. The snap-on assembly allows for the use of an integrated round bag ring separator and larger balls. Type A angular contact bearings can withstand radial loads and unidirectional thrust loads and are usually used in combination with another bearing of similar construction. Type A angular contact bearings have a 30° contact angle and approximately 67% full ball complement. The main advantage of an A-type bearing is that it can carry greater thrust loads than a C-type or X-type bearing.
X-type bearing (four-point contact)
The Gothic arch geometry of the inner and outer rings of the Reali-Slim Type X four-point contact bearing enables a single bearing to carry three types of loads (radial, axial and moment) simultaneously. This makes it a prime option for many applications, as a single four-point contact bearing can often replace two bearings, greatly simplifying the design. For applications requiring greater stiffness or zero free play, X-type bearings can also be equipped with internal diameter preload. This is achieved by using balls that are larger than the space between the raceways. Therefore, in the absence of external loads, the balls and raceways will undergo some elastic deformation. Note: Kaydon does not recommend using two X-bearings on the shaft at the same time as this may cause additional frictional torque.
Reali-Slim thin section bearing installation
Reali-Slim bearings have a very thin cross-section and are therefore sensitive to the fit of the shaft and housing. Proper installation is critical to ensuring thin section bearings perform as expected. There are many factors to consider when installing a bearing, including: bearing type and orientation, direction and magnitude of applied load, free play allowed in the bearing, maximum allowable torque, shaft and housing material, operating temperature, and which ring is rotating. The installation of Reali-Slim thin section bearings requires special attention to ensure their high accuracy and long service life. The following are several key points for thin-section bearing installation:
Installation Environment. Keep the installation environment clean. Cleanliness is critical to bearing performance. Work surfaces and tools must be free of dust, debris and burrs. Use disposable wipes or cotton cloths for cleaning to avoid debris sticking to the bearings when grinding and machining mating parts, as even small amounts of abrasive particles and debris can seriously affect bearing accuracy.
Matching of bearings and shafts. For thin-section bearings, the interference fit between the mounting hole and the shaft needs to be handled carefully to avoid damage to the bearing. It is recommended to use temperature differences to expand external components and reduce or eliminate mounting forces. There are different expansion rates for bearings and shafts of different materials (such as AISI 52100 steel and AISI 440C material).
Installation method. According to the bearing model and size, choose the appropriate installation method, such as manual installation, mechanical press installation or cold shrink installation. Manual installation is suitable for small bearings, while mechanical press installation is suitable for large bearings. Cold shrink installation requires a higher technical level.
Installation direction and parallelism. The installation direction of thin-section bearings should be such that the loads on the inner and outer rings become radial loads as much as possible to avoid unnecessary swings, which will affect the bearing life.
Bearing cleaning and maintenance. Before installation, carefully check the bearing mounting hole diameter, shaft diameter, shoulder verticality and fillet size. After installation, continue to protect the bearings from contamination until they are assembled.
During the installation process, do not press hard on the bearing and avoid using hard tools to hit the bearing surface to avoid damage. At the same time, check the usage of the bearings regularly. If there are any abnormalities, they should be cleaned and replaced in time.
Reali-Slim® Thin Section Bearing Applications
Reali-Slim® thin-section bearings are widely used in aerospace, automotive industry, medical equipment, robotics and high-speed railways due to their lightweight, compactness, efficient performance, high speed, long life and reliability. With the continuous advancement of technology and increasing application requirements, thin-section bearings will continue to play an important role in promoting continuous development and innovation in various fields.
Aerospace: Due to their lightweight and efficient performance, thin-section bearings are widely used in the aerospace field for rotating parts of aircraft and spacecraft, such as engines, spindles and transmission systems.
Automotive industry: Thin-section bearings are widely used in key parts such as engines, transmissions and suspension systems in the automotive industry to improve the performance and reliability of the car.
Medical equipment: Due to the miniaturization and precision manufacturing of thin-section bearings, they are widely used in various medical equipment, such as surgical instruments, diagnostic instruments and treatment equipment, etc.
Robots: With the continuous development of robot technology, thin-section bearings are widely used in robot joints and rotating mechanisms to improve the motion performance and stability of robots.
Precision machinery: Thin-section bearings can be used in various precision machinery, such as precision machine tools, instruments and meters, etc.
Conclusion
Reali-Slim® thin section bearings are precision and widely used bearings. This article provides a comprehensive description of useful information on Reali-Slim® thin section bearings. It is worth noting that Reali-Slim® thin-section bearings are very expensive, costing thousands or even tens of thousands of dollars. This is not friendly to small and medium-sized companies and individual enthusiasts. Fortunately, Aubearing is a manufacturer and leader of thin section bearings in China. Reali-Slim® thin-section bearings manufactured by Aubearing are equivalent to the Kaydon series and are a replacement for its entire thin-section bearing series. The price is only one-tenth of the same model from Kaydon, which greatly reduces the cost of the design and provides economic benefits. If you are not sure which Reali-Slim® bearing model to choose, please contact an Aubearing engineer today. They will respond quickly and make the right decision for you.