Exsev and Ceramic Special Environment Bearings
The Ceramic and EXSEV Bearings are designed for applications operating in extreme special environments where conventional bearings are not suitable for.
These bearings have an optimal operation in extreme environments like clean, vacuum, high temperature, corrosive and contaminating conditions. They are already being used in an extensive range of applications and state of the art technologies.
Ceramic bearings consist out of components made from ceramic and can be used in applications where conventional bearings are not suited for. They have special characteristics which steel bearings do not have such as being non-magnetic or insulating. Ceramic bearings are highly heat resistant, have a longer service life and can be divided into Full Ceramic Bearings and Hybrid Ceramic Bearings. The components of our Full Ceramic Bearings are all made of ceramic. The Hybrid Ceramic Bearings have only the rolling elements which are from ceramic. The outer and inner ring of the Hybrid Ceramic Bearing is made from special steel, including high carbon chromium bearings steel. Furthermore the cage can be made of metallic material, resin or composite material depending on the intended operating conditions of the bearing.
Bearings made of stainless steel without rust preventive oil are perfectly suitable for operation in clean environments. This bearing can be used in combination with an amount of low particle emission type of lubricant based on the operating conditions such as temperature, load and rotational speed. At JTEKT these special Koyo branded bearings are being lubricated with a Clean Pro coating or fluorinated grease. Fluorinated grease is superior to solid lubricants in load carrying capability and high speed operation. This grease can be used in applications where a scattering of slight amount of fluorinated oil is acceptable.
In a vacuum environment JTEKT developed Koyo bearings from which the outer/inner rings and balls are made of martensitic stainless steel. For bearings which are requiring corrosion resistance, precipitation hardening steel is used. When high temperature resistance is required high speed tool steel can be used. Vacuum environments where cleanliness is critical, bearings have to be clean and polymeric material or fluorinated grease should be used.
High Temperature Environments
Hybrid Ceramic bearings can be used for high temperature applications. The rings of these bearings are made of highly heat resistant high speed tool steel and the balls are made of ceramic. The use of a lubrication type can be decided based on the temperature:
- Up to 200 degrees Celsius, fluorinated grease can be suitable
- Over 200 degrees Celsius, layer lattice material can be used
- Over 500 degrees Celsius, an un-lubricated full ceramic bearing should be used
Bearings which should operate efficiently in corrosive circumstances are made of special materials. The selection of a Koyo Ceramic bearing for the use in a highly corrosive environment should be examined very carefully.
Beneath are some examples:
- Corrosion Resistant Hybrid Ceramic Bearings: are suitable for applications which have to run in water, an alkaline environment and reactive gas.
- Ceramic Bearing: are suitable for applications which have to run in a slightly acidic and alkaline environment in combination with reactive gas.
- Corrosion Resistant Ceramic Bearing: are suitable for applications which have to run in a very strong acidic and alkaline environment in combination with reactive gas.
- High Corrosion Resistant Ceramic Bearing: are suitable for applications which have to run in a very strong acidic and alkaline environment in combination with corrosive gas.