Bearing Cage and Separator Materials

This material is available either machined or moulded and represents a low cost, lightweight cage option that is ideal and suitable for applications below 100°C.

However, Nylon/Polyamide does not represent a strong choice of cage in a vacuum application as the material will ‘gas out’ and contaminate the environment.

Due to their lightweight and insulating properties, this material is the suitable choice for hybrid, electrical, or high-speed applications.

Polyether ether ketone is more commonly know as ‘PEEK’ and is the preferable material for use in clean, ultra-high vacuum environments as it has low particle generation and will not ‘gas out’ an environment within a vacuum. It is incompatible with any acids or corrosive solutions but is temperature resistant to approximately 150°C. This cage can be used with both hybrid and fully ceramic bearings.

This material is an industry standard choice for many applications with high temperature, vacuum, or clean requirements as metal cages can take many forms. 52100 steel or stainless-steel cages are common in a variety of hybrid bearings as they match the material used for the races, providing a low-cost option that will be suitable for many applications. Exotic alloys could be used in special circumstances; however, this would no longer provide a low-cost option. Carbon steels are not the ideal choice for non-magnetic or electrical applications due to their conductive behaviours.

PTFE is a chemically resistant, insulating, and non-magnetic material that is used throughout a variety of industries. Its strong covalent bonding of the fluorine and carbon, PTFE has strong chemical resistance and is hydrophobic.

However, PTFE does not have a high load bearing capacity and isn’t suitable for high temperature applications. PTFE can be used in both full ceramic and hybrid bearings.

Brass cages can be both crown ball pocket and riveted type, they offer a very durable heavy-duty solution, particularly at heightened running temperatures. A brass cage is not usually suitable for high-speed applications and is commonly found in larger bearing assemblies.

Phenolic cages are both strong and lightweight, making them ideal for high speed applications, they can be supplied in a ball-pocket crown and two-part riveted with additional options for metal backing and reinforcing.

Phenolic is produced by impregnating textile with a thermosetting resin. The resulting component, when machined to required sizes provides a low coefficient of friction, the material is able to absorb lubricants and maintain dimensional rigidity whilst offering a high strength-to-weight ratio in conjunction.

Full complement (no cage) negates all the issues with using an additional material for a cage therefore making it a possibility for applications including ultra-clean, vacuum, high-temperature, nonmagnetic, corrosive, and electrical. The principle of a cage or supporter is to prevent the balls in the bearing from making contact; without a cage or supporter this will inevitably occur. This then causes high-contact stress and abrasion, which causes residue to wear the elements and races that results in increased torque and reduced fatigue life.

Full complement bearings are suitable for radial loading applications only.

These options essentially replace the cage with a separator that floats between each of the balls. The materials used would need to be the same materials listed for the cage for full compatibility and performance.

These options are suited to applications that have low speed and torque, such as slow-moving oscillating applications.

Bearing cages can also be produced in speciality materials to suit specific applications including ceramic, Vespel®, Meldin® moly disulfide impregnated PEEK, aluminium, Delrin®, and graphite.