How the Ceramic ball bearings work?
The simple explanation to this is to understand first of all how the ball bearings work and what is the basic principle behind them.
The basic function of any ball bearing is to reduce friction between the two elements because rolling things have less friction than the sliding things and the reason is not hard to fathom. If things were to slide instead of roll the entire surface of the two things sliding against each other would be in touch which means more friction and more resistance.
When things are rolling they have less friction because of the fact that they have less amount of surface in contact and that means that less friction and resistances.
The bearings then actually have an inner surface to roll over and outer surface to roll over. These balls then get most of the load and but of course then there are various kind of ball bearings for different applications.
Roller ball bearings have three components namely the outer race and the inner race. Balls get the load from the outer race and transfer the load to the inner race. But roller ball bearings can only handle small amounts of load since the balls have less area of contact to the races.
Roller bearings are a variety of ball bearings in the sense they do not have the balls but a cylinder where the bearings come in contact over a large area and that means that they can in fact handle larger loads. The variety used in cars is the tapered roller bearings and that means that they can in fact handle larger loads and also they are used in pairs so that the load can be handled in both the directions.
Nowadays a lot of ceramic ball bearings are being used since they are lighter than steel and generate less heat and hence can go faster than steel. The ceramic material can be silicon nitride or silicon carbide or zirconium.
Again you can have entire ball bearing built out of ceramic material or you can have only the balls of the bearings built of ceramic.
What is the material used for ceramic ball bearings?
Coming to use and the advantage of ceramic ball bearings the advantage of a ceramic ball bearings is that it can withstand huge amounts of heat because of the material it is made up of. These ceramic ball bearings are less strong than steel but even then they are in demand because of the fact that these are lighter and hence go faster than the traditional steel ball bearings.
The ceramic material which is used in these ball bearings is the silicon nitride or silicon carbide or zirconium.
This material was developed for use in aerospace shuttles when they entered the earth’s atmosphere. These are called the heat shields on the exterior of the space shuttles. These are made up of highly processed silica and ceramic material.
The advantage that these offer is immense as these are virtually indestructible and have advantages over the traditional steel balls. The balls are processed so that they are not brittle which a drawback of the ceramic ball bearings was once.
The tests have proved that the ceramic ball bearings have longer life shelf as opposed
to the conventional steel balls. In the conventional ball bearings the surface wear is very common and that causes the surface to weld together and get damaged even during the lubrication. That is not the case with ceramic ball bearings. Also there is less wear and tear the side effect is that even the lubricants have a longer shelf life.
The net effect is that running speed is 40-50% greater than the steel ball bearings as well as longer lube life for the lubricant. Most of these ceramic ball bearings are used in wide range of industries beginning with aircrafts, biotechnology equipment, pumps and compressors and even the precision mills and other uses wherever there is need for high speed as well is high heat generated.
Types of ceramic ball bearings - full, partial or hybrid
A Ceramic Hybrid Ball Bearing is a precision bearing in which one or all of its components are made of ceramic elements from silicon nitride. Silicon nitride is a form of highly processed silica and ceramic material.
The Ceramic hybrid bearings have the characteristics such as heat resistance, extended life, light weight, lower thermal expansion, electrical non- conductance and thus can be used in an infinite number of applications. It has been found that there are several common designs of ball bearings they can be made from many different materials, including: stainless steel, chrome steel, and ceramic (silicon nitride (Si3N4)). A hybrid ball bearing is a bearing with ceramic balls and races of metal. Ceramic hybrid ball bearings use these ceramic balls in place of steel balls. They are constructed with steel inner and outer rings.
There are three types of Ceramic Ball Bearings;
1. Ceramic Hybrid Ball Bearings : Where the rolling elements, or balls, are ceramic, but the inner and outer rings are still conventional steels.
2. Partial Ceramic Ball Bearings: Where the rolling elements, and the inner ring are ceramic, but the outer ring is still made of steel.
3. Full Ceramic Ball Bearings: Where the rolling elements, inner, and outer rings are made of silicon nitride.
The execellent characteristic of the ceramic ball beraings are :-
Lightweight : As the density of the ceramic ball bearings is 40% lower than that of steel, which allows the centrifugal force from the rolling elements lower, thus extending the life of the bearing.
Low Coefficient of Linear Expansion : In applications involving high speed operation, although the temperature of the bearing is high, this low coefficient results in lower preload and lower heat generation.
Low Friction : The slip of the rolling element during operation is reduced, resulting in less heat being generated.
The use of Ceramics for bearing components results in a far superior product over traditional all steel ball bearings.