Cage types and - designs

This technical file offers a summary of cages for antifricition bearings which are on MPT's standard production programme. It also shows classification of standard cages to their bearing series, rows and sizes.

The cage as important part for bearing function as it

  • holds the rolling elements apart in task to avoid their contact
  • holds the rolling elements in equal distances to improve load distribution
  • guides the rolling elements in unloaded bearing zone
  • avoids that rolling elements fall out in special bearings and supports bearing mounting

Cages are distinguishable into steel cages and brass cages, consisting of various materials.

Steel cages are mainly pressed or cutted from steel sheet metal, also brass sheet metal is used sometimes.
Their advantage against brass cages is the very small weight as well as the easier way to lubricate the bearing inside due to more space between inner and outer ring.

Solid cages consist of brass, steel, light metal, sinter iron and phenolic. Manufacture process for metal and phenolic cages is consisting of turning and milling. Cages made out of plastic materials are manufactured by injection molding. On special occasions solid cages are manufactured from sinter iron (which is good able to slide, wear resistant and thermal conductive).

Solid cages, especially brass and steel cages, are used for smaller series and for reasons of strength used in large, high loaded bearings.

Solid cages made out of light metal or phenolic have relatively small force of gravity and are often used in high-speed bearings as outer lip guided version.

Cages made from glass fibre reinforced polyamid PAGF25 are now used in various large series bearings. High elasticity, small weight and good sliding - and dry running properties are reasons influencing bearing life positive.

Glass fibre reinforced polyamid cages are qualified for lasting temperature up to 120 C. Usage of oil lubrication might affect cage life due to oil contained additives. Also old oil has affects to time of cage usage. Therefore it is necessary to care for given oil changing times.

The economical favourable standard cages fulfil demands under normal circumstances of usage. Special conditions of usage require cages especially chosen. This explains the wide range of cage designs shown in this technical file.

Another characteristic of differing cages is their way of guidance. Most of the cages are guided by their rolling elements. This guidance does not apply to cage grammalogue.

Cage guidance on outer ring of bearing (outer lip guided) and on inner ring (inner lip guided) are indicated with A respectively B in cage grammalogue.


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