Hard disc drive bearings

Bearings sector
Cylindrical roller bearings	Hard disc drive bearings
Spherical roller bearings	Four point bearings
Taper roller bearings	Angular contact ball bearings
Rolling elements	Deep groove ball bearings

Overview
There are fundamentally two types of hard disc drive bearings which are those based on standard contact ball bearings and those based on fluid dynamic bearings.

The form, radius and surface finish of the tracks is critical to the running performance and noise characteristics of these bearings. Taylor Hobson have a range of Form Talysurf systems which are suitable for measuring the form and surface finish characteristics of hard disc drive bearings.

The products include:

Talysurf CCI Systems
Nanometric areal surface texture and groove analysis on hard disc drive bearings.

Form Talysurf PGI Bearing Measurement Systems
Medium to large capacity systems for highly accurate measurement of surface texture and geometrical features on hard disc drive bearings.

Form Talysurf Inductive systems
Small capacity systems for accurate measurement of surface texture and geometrical features on hard disc drive bearings.

Talyrond 290 / 280 range
Large capacity systems for highly accurate measurement of roundness and harmonics on hard disc drive bearings.

Talyrond 295
At the heart of the Taylor Hobson range of roundness instruments is the TR295 this instruments high precision spindle, straightness datums and position control enable measurement of the most exacting components.

Talyrond 365 / 240 range
Medium capacity systems for highly accurate measurement of roundness and harmonics on hard disc drive bearings.

Fluid dynamic bearings
In fluid dynamic bearings, the bearing function is taken over by a layer
of lubricant less than one tenth the thickness of a human hair. The rotor supported by the bearing essentially swims around the shaft. The elimination of metal to metal contact in fluid dynamic bearings eliminates non-repeatable runout due to surface imperfections. This makes it possible to reduce track spacing and increase the tracks per inch on the disk.

Control of surface finish, roundness and waviness is critical to the performance of fluid dynamic bearings. However there are also typically grooves machined in the shaft and rotor of FDBs’ which assist in the build up of a stable lubrication layer.

Through co-operation with manufacturers, Taylor Hobson has developed a special analysis tool for analysing the shape and ratio of the grooves on FDB’s.

For further details contact your local sales representative