Rolling type by steel ball or roller.
- Peripheral structure of bearing
- Use in either high temperature
or low temperature is comparatively easy.
- Can increase stiffness of bearing
- International standards and specifications
have been established.
- Friction heat takes place by
contact when ball rolls.
- Ball and out of roundness of
orbital plane are very important.
- High speed spinning is not possible.
Spindle levitates by compressed
- In high speed rotation, heat
by shearing resistance
of air film hardly takes place as viscosity
of air which
is working fluid is very low
(1/100 ~ 1/5000 of viscosity of oil).
- High speed spinning is possible.
- Product life is semi-permanent.
- Pneumatic system should be equipped.
- Machining is not easy.
- Has less stiffness than ball