Fluid bearing in the context of Wear

⭐ Core Definition: Fluid bearing

Fluid bearings are bearings in which the load is supported by a thin layer of rapidly moving pressurized liquid or gas between the bearing surfaces. Since there is no contact between the moving parts, there is no sliding friction, allowing fluid bearings to have lower friction, wear and vibration than many other types of bearings. Thus, it is possible for some fluid bearings to have near-zero wear if operated correctly.

They can be broadly classified into two types: fluid dynamic bearings (also known as hydrodynamic bearings) and hydrostatic bearings. Hydrostatic bearings are externally pressurized fluid bearings, where the fluid is usually oil, water or air, and is pressurized by a pump. Hydrodynamic bearings rely on the high speed of the journal (the part of the shaft resting on the fluid) to pressurize the fluid in a wedge between the faces. Fluid bearings are frequently used in high load, high speed or high precision applications where ordinary ball bearings would have shortened life or caused high noise and vibration. They are also used increasingly to reduce cost. For example, hard disk drive motor fluid bearings are both quieter and cheaper than the ball bearings they replace. Applications are very versatile and may even be used in complex geometries such as leadscrews.

↓ Menu

HINT:

In this Dossier

⭐ Core Definition: Fluid bearing
Fluid bearing in the context of Viscosity index improver
Fluid bearing in the context of Disk read-and-write head

Fluid bearing in the context of Viscosity index improver

The viscosity index (VI) is an arbitrary, unit-less measure of a fluid's change in viscosity relative to temperature change. It is mostly used to characterize the viscosity-temperature behavior of lubricating oils. The lower the VI, the more the viscosity is affected by changes in temperature. The higher the VI, the more stable the viscosity remains over some temperature range. The VI was originally measured on a scale from 0 to 100; however, advancements in lubrication science have led to the development of oils with much higher VIs.

The viscosity of a lubricant is closely related to its ability to reduce friction in solid body contacts. Generally, the least viscous lubricant which still forces the two moving surfaces apart to achieve "fluid bearing" conditions is desired. If the lubricant is too viscous, it will require a large amount of energy to move (as in honey); if it is too thin, the surfaces will come in contact and friction will increase.

View the full Wikipedia page for Viscosity index improver

↑ Return to Menu

Fluid bearing in the context of Disk read-and-write head

A disk read-and-write head is the small part of a disk drive that moves above the disk platter and transforms the platter's magnetic field into electric current (reads the disk) or, vice versa, transforms electric current into magnetic field (writes the disk). The heads have gone through a number of changes over the years.

In a hard drive, the heads fly above the disk surface with clearance of as little as 3 nanometres. The flying height has been decreasing with each new generation of technology to enable higher areal density. The flying height of the head is controlled by the design of an air bearing etched onto the disk-facing surface of the slider. The role of the air bearing is to maintain a constant flying height as the head moves over the surface of the disk. The air bearings are carefully designed to maintain the same height across the entire platter, despite differing speeds depending on the head distance from the center of the platter. If the head hits the disk's surface, a catastrophic head crash can result. The heads often have a diamond-like carbon coating.

View the full Wikipedia page for Disk read-and-write head

↑ Return to Menu

Fluid bearing Study page number 1 of 1

Play TriviaQuestions Online!

Skip to study material about Fluid bearing in the context of "Wear"

⭐ Core Definition: Fluid bearing

Fluid bearing in the context of Viscosity index improver

Fluid bearing in the context of Disk read-and-write head