CERAMIC BALL BEARING

-BY NAMITHA C.M

UNDER THE GUIDANCE OF

Mrs. H.M KAVYA

Lecturer

CONTENTS Introduction What is a Ceramic Hybrid Ball Bearing? Working principle Types of Ceramic Ball Bearings Features Technical Charts Ceramic vs. steel ball bearings Applications Advantages and Limitations Conclusion References

Introduction Starting in 1963, Silicon Nitride was developed by NASA

for Thermal Protection Systems for the space program at the University of Washington's Department of Material's, Science and Engineering. Eventually, manufacturers of various products, from the starting block of all machinery, the ball bearing, to manufacturers of complete ceramic engine assemblies, have been slowly discovering the benefits and various uses of today's hi-tech ceramics. The machine tool industry has been a pioneer in the use of ceramic hybrid ball bearings. Many different types of hi-performance motor racing programs, like Formula 1, are

also discovering the advantages of using ceramic hybrids.

What is a Ceramic Ball Bearing?

We can achieve new friction reducing Ceramic ball bearings

A ceramic ball bearing made of ceramic elements from silicon nitride. A ball bearing is a piece of equipment that uses balls to reduce friction in spinning system.

Working Principle

The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads. It achieves this by using at least two races to contain the balls and transmit the loads through the balls. One of the races is held fixed. As one of the bearing races rotates it causes the balls to rotate as well.

Types of Ceramic ball bearings

•Hybrid ceramic ball bearing

•Partial Ceramic Ball Bearings

•Full Ceramic Ball Bearings

Common Designs Angular contact

An angular contact ball bearing uses axially asymmetric races. An axial load passes in a straight line through the bearing, whereas a radial load takes an oblique path that tends to want to separate the races axially.

Deep groove

In a deep-groove radial bearing, the race dimensions are close to the dimensions of the balls that run in it.

Axial

An axial ball bearing uses side-by-side races.

Features

60% lighter than steel balls. 50% higher modulus of elasticity. Tribochemically inert. Non-conductive. Less maintenance. Coefficient of Friction. Low Density.

High Hardness. High Hot Strength. Low Coefficient of Thermal Expansion. Long Fatigue Life. Corrosion Resistance. Micro weld.

Technical Charts

Ceramic vs. Steel ball bearings

Density

Modulus of elasticity

Sensitivity

Friction

Applications

Motor Racing. Motorcycle Racing. Machine tool applications. Aircraft accessories/aerospace. Industrial Machinery. Medical equipment.

Advantages

Ceramic balls are lighter, smoother, stiffer, harder, corrosion resistant, and electrically resistant.

Ceramic ball bearings are 2 to 5 times longer life than steel for most applications.

One of the major advantages of the all ceramic bearings is the capability of dry run in the rolling contact.

In a ceramic bearing, the material is so resilient to heat expansion that temperatures of around 1200 degrees F can be placed on the material without much expansion.

Limitation

Ceramic balls cannot be used for every application. A stiffer ball can increase contact stresses if raceway curvatures are not adjusted.

Silicon nitride balls are more costly than steel balls and while they continue to be more and more affordable, they may not be economical for every application despite longer life and enhanced performance.

Conclusion Ceramic ball is tremendously harder than steel. Ceramic

ball is 60% lighter than a steel ball. Ceramic ball is significantly rounder and has a finer finish than conventional steel balls. Operating temperature for ceramic is 1093 degree centigrade versus 316 degree centigrade for steel. Vibration levels of ceramic hybrid bearings average two to seven times lower than that of steel. Service life is two to five times longer than conventional steel ball bearings. 25% of all electrical energy produced is used to power some type of electric motor. Imagine the savings in resources if all motors were to run with ceramic hybrid ball bearing.

References

Popp, M. & Sternagel, R CEROBEAR GmbH, Kaiserstraße 100 D-52134 Herzogenrath

Xiaofan Xie Dept. of Mechanical Engineering, University of Utah

Shin Niizeki, “Ceramic Bearings for Special Environments”, Motion Control No.8 (May 2000).

Ira Krepchin, “Ceramic bearings on a roll”, Design news, December