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.Bearings
basics |
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Different bearing types -
What
is a ball bearing? -
What
is a ball bearing made for? -
When
did ball bearings appear? -
Who is
manufacturing ball bearings? |
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Different
bearing types
There are more than one hundred bearings types with different shapes and
designs. To simplify they can be divided in two main families, ball
bearings and roller bearings. Roller bearings are generally used in
high-load applications. They are often found in industrial applications,
mainly as large size bearings. For skates both inline or quads, or for
skateboards one will never find roller bearings but only ball bearings;
more specifically deep groove ball bearings. To simplify, we will call
them ball bearings in the following pages. Ball bearings are the
simplest and most popular bearings. They are found in large variety of
applications, such as cars, air dryers, washing machines, lifts, etc.
Therefore SKF ensures to have worldwide availability. Further, as most
popular ones, they also have an attractive price.
What is a ball bearing?
A ball bearing consists of following parts:
An outer ring
An inner ring
A number of balls
A cage
Lubricant (for sealed bearings)
Protection (sealing)
What is a ball bearing made for?
Ball bearings ensure a mechanical link between a rotating part and a
stationary part. For example: ball bearings are used to guide and
maintain the wheel that is rotating relative to the axle that is fixed
on the frame. The internal design of the bearing ensures the wheel to
have low friction and precise rotation. But we will come back later on
that subject.
When did ball bearings appear?
Leonardo da Vinci has drawn the first ball bearings in the 15th century.
First prototypes have been made in wood. In the early 18th century,
scientists have thought to make them of steel and to use them in
transport systems. Nevertheless it's only towards the end of the 19th
century that ball bearings have been made to acceptable quality and
produced in quantities for applications such has railways, industrial
steam machines, and cars. At that time, bearing manufacturers made
bearings to any dimension, this created a lot of problems of
interchangeability. After world war 1 the bearing manufacturers begun to
think about standards, in order to standardize bearing sizes, and to
define the main characteristics. Though, in the 50's, appeared the ISO (International
Standard Organization) standard systems. These are the only
international standards to describe bearing dimensions and main
characteristics. For example this explains why a ball bearing of
dimensions 8x22x7 mm is called 608. Sometimes, like for inline skate
bearings, ancient American ABEC standards are still being used.
Who is manufacturing ball bearings?
Of course SKF does! Since the beginning the ball bearing industry was
considered as strategic by all industrialized countries. The bearing
industry has become really international over the past 20 years, with
worldwide companies able to provide the complete bearing range. There
are 5 important ball bearing manufacturers, said to have high quality
and serious technology. Not all of them produce 608 or mini-bearing
sizes like SKF does. |
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