Ultra Thin Ball Bearings

Distributor of inch & metric thin section ball bearings. One, pair & tri-packs available in stock with low torque, high speed ratings & corrosion resistance.

An aircraft gun turret needed a bearing which would take radial, axial and moment loading. This was achieved with a duplex RBC Thin Section Ball Bearing designed as an angular contact type.

Material

Stainless steel thin section bearings can be used in a wide variety of applications including aerospace, robotics, medical equipment, cameras and optical equipment. They have larger bore diameters than standard ball bearings but have a smaller overall bearing cross-section. This allows them to fit into tight spaces while maintaining low rotational torque and rotational accuracy.

Typical thin section bearings have a high load capacity, good running accuracy and operate in temperatures up to 120degC constant or 150degC intermittent. Those that operate at higher speeds can be made from exotic materials like tungsten carbide or specialized nickel alloys that provide better performance under extreme conditions.

Silicon nitride ceramic bearings have a lower weight than steel balls and reduce centrifugal force. They also operate well in high temperature environments and resist corrosion. They can be lubricated with a non-contaminating oil and have the added advantage of being self-lubricating. Kaydon has a line of hybrid ceramic ball bearings that combine inner and outer rings of stainless steel with ceramic balls. These reduce friction and vibration and allow the bearing to spin up to 40% faster.

Balls

Thin section ball bearings reduce rotational friction while supporting radial and axial loads. They are a cost effective solution for many applications where a larger diameter would require a larger shaft or space limitations would prevent the use of standard bearings.

The balls of thin section bearings are sized in series with the cross-section size and are matched to each other. A selection of bearing materials is available including glass (soda-lime), ceramics, and stainless steel. In addition, silicon nitride is increasingly being used because it resists corrosion and function well in high temperature environments.

A preloaded duplex pair of angular contact RBC thin section ball bearings were designed to meet the low torque, multiple load capacity and corrosion resistant requirements of an airborne turret azimuth drive assembly. They were configured with toroidal separators in stainless steel rings that maintained the low load torque. This design also provided the radial runout, stiffness and vacuum operation capabilities required.

Seals

As the name implies, ultra thin ball bearings have a smaller cross section than standard deep groove bearings. This minimizes the space required and helps to reduce weight in an application. This can be a major benefit in systems where space and weight are significant factors such as airborne optical and infrared scanning equipment, robotics or construction machinery.

Kaydon’s 69 Series of ultra-thin ball bearings are available in open or sealed variants with a locating snap ring. They can be used in a variety of applications that require lower torque and smoother rotation such as industrial robots, rotary encoders or stepping motors.

Seal options for these ultra-thin deep groove ball bearings include non contact seals and shields which have a gap between the lip portion of the seal or shield and shaft. This is typically filled with lubricant. Another option is contact seals which make direct contact with the bevelled portion of the inner ring sealing groove. This requires the use of a different type of lubricant (typically Buna N rubber) and is more suited for higher speed applications.

Design

Due to their small cross sections relative to bearing diameters, thin section bearings allow for reduced system costs by reducing space requirements and weight. They also reduce the total amount of load in a system, which can help decrease overall friction and vibration.

Thin section ball bearings are ideal for robotics, inspection equipment and satellites. They are used in applications with light to medium duty loads that require low rotation speeds, and they are often exposed to harsh environments. Kaydon’s ultra-slim thin section bearings are made from honed 440C stainless steel to ensure optimal performance.

Proper shaft and housing fits are critical to the successful operation of these bearings. A poor fit can distort the inner and outer ring raceways, which will increase radial play and reduce operating life. For the best results, a slight press fit is recommended. Click on INFO to view technical drawings with load and speed ratings. These ratings are based on test results at room temperature and may be affected by shaft and/or housing roundness, lubrication, alignment and ambient temperature.