View A Video on Ball Bearings - A Quick Introduction
Bearings are tools that allow for relative motion between objects. They
are used in a wide variety of contexts and are available in an equally
extensive variety of configurations; bearings can be spherical,
cylindrical, needle-shaped, tapered and many other shapes. Ball bearings
in particular use rolling spherical elements to facilitate smooth
radial or axial motion within a system.
Bearings reduce the amount of friction between components in a system, which allows for heavier objects to be moved with less effort. These bearings provide smooth movement of parts or whole pieces of equipment; without these components parts would wear out quicker and would require frequent maintenance or replacement. There are many different kinds of bearings; just a few examples include angular contact bearings, deep groove ball bearings, automotive bearings, precision ball bearings, sealed bearings, pillow block bearings, roller bearings and many other varieties. Most bearings are capable of handling both thrust and radial loads. Bearings can be made out of steel, ceramics and other materials. Specific design allows for certain bearings to handle differing proportions of each load type based on the bearing's intended application. Ball bearing manufacturers and providers of ball bearings offer a range of bearing sizes and dimensions, beginning with the smallest miniature bearings and ending with bearings as large as tens of feet in diameter. The use of ball bearings is common in many industrial and commercial settings, such as assembly lines and as part of a conveyor belt system.
In general, bearings are small components placed between moving parts to reduce friction with movement. They can be made of many different materials and can be of various sizes and designs. Angular contact bearings carry loads that move in a straight line through the bearing. They have asymmetrical races where one shoulder is higher than the other. Deep groove ball bearings can carry both radial and axial loads. These bearings, in addition to angular contact bearings, compose the radial ball bearing category. In contrast, thrust bearings are designed to handle pure thrust motion only. Thrust bearings are used in low speed applications and can be found in products like barstools. Besides the direction of the loads, bearings also vary by materials. Steel ball bearings are the most common kind. They are strong, durable and corrosion resistant. Ceramic bearings, however, have a lower rate of thermal expansion and are generally more heat resistant than steel. Because ceramic is a less dense material, these bearings create less friction. Combinations of ceramic and steel are widely available to maximize the benefits of both materials.
Ball bearings are extremely useful and are used in many applications. For example, automotive bearings are used in many assemblies and parts found in vehicles, including suspension bearings and wheel clutches. In certain situations, standard ball bearings are incapable of achieving the desired performance and a specialty bearing must be used. Precision ball bearings can perform quietly at high operating speeds. They also have a longer lifespan than regular ball bearings, are quieter and require less maintenance. Miniature bearings are smaller than conventional bearings and must accordingly carry smaller torque loads. Sealed bearings have rubber sides that protect the balls from contamination in environments where moisture, chemicals or fine particles are present. Sealed bearings are also used in places that are infrequently accessed or where maintenance is impractical because the bearing is difficult to access. Pillow block bearings are mounted units that allow a shaft to smoothly glide in and out of the casing with little friction, resistance or heat. They are basically a ball bearing inserted into a mountable enclosure. Roller bearings provide an alternative to the round spherical balls typically used in ball bearings. They used cylinders to evenly distribute the weight of the load over a large area. Like ball bearings, roller bearings rotate and spin around the races inside the inner and outer rings.
Ball bearings have been used since ancient times. Some scholars speculate that the Egyptian pyramids were built using logs as roller bearings to transport the heavy stones over long distances. Today, bearings are still capable of carrying massive loads, but they do so with more refined techniques and advanced materials. Today's bearings are usually a few inches in outer diameter and use approximately a dozen balls to provide smooth motion. Despite their comparatively small size, these bearings are able to consistently handle large loads while spinning at high speeds. The interiors of the rings are engineered and then machined very precisely to achieve a uniform and consistent raceway for the balls. The balls are also carefully constructed; they pass through a stamping machine that creates identical balls. If even one ball is lopsided, the load capabilities and speed of the bearing and the larger system will be reduced. Steel and ceramic are chosen for their many benefits and their composition has been adjusted through use of alloys and other additives in order to maximize the advantageous characteristics. When ball bearings are assembled, they are lubricated and packed in a clean environment to avoid contamination, which may inhibit the performance of the bearings.
Ball Bearings Types
- Angular contact bearings
are a type of radial bearing that is designed so that one shoulder of the rings is higher than the other, creating a contact angle
between the races and the balls.
- Automotive bearings are used for a wide range of automotive purposes.
- are also sometimes called precision bearings and are rated on a scale from one to nine based on precision standards.
- Bearings are components that are used in between moving parts to reduce friction.
- Ceramic ball bearings are made of ceramic instead of steel; some of these bearings use both materials.
have one race shoulder turned and ground away to facilitate an assembly
with a greater number of balls.
- Deep groove bearings are the most common type of radial bearing.
- are used to move objects in a single axis.
- allow for more balls to be loaded into
the bearing using the filling notches.
are smaller bearings with bores of ten millimeters or less.
- Pillow block bearings contain an enclosed ball bearing within a mountable enclosure.
- are composed of materials that are subjected to
severe stress reversals.
- move in both directions and can handle large
- use cylindrical rollers instead of balls to carry heavier loads than standard bearings.
- Sealed bearings have rubber sides that seal out contaminants such as dust, oil or moisture.
- consist of two rows of balls and a spherical
raceway in the outer ring that work to minimize misalignment.
- use balls as the rolling element and are used for inline skates
made of steel materials and are the strongest kind of bearings available.
are bearings that bear axial loads.
Ball Bearings Terms
the bearing is mounted; it is an imaginary line that runs through the
center of the shaft.
Ball Cage - Device used to space the
balls. The cage partly surrounds the balls and moves with them.
- Container that
holds the balls in place.
- The smallest dimension
when referring to the separator, inner ring or outer ring of a ball bearing.
- A mechanical component
that facilitates the movement of two objects relative to each other.
- Inner ring of tapered
- Formed by a
line drawn between the areas of ball and ring contact and a line perpendicular
to the bearing axis.
- A load placed
on a bearing that is in motion.
- A breakdown of a bearing after sustained use.
- The amount of internal
clearance in a bearing. This can also refer to shaft and housing size
and how they relate to the bore or outside diameter.
- Bearing that
is able to move in one or two directions.
- The innermost part
of a bearing, which fits on a shaft and contains the external raceway
for the rolling elements. Occasionally the shaft is immobile and the housing
- A nut used in tandem
with a lock washer to hold a bearing in place on a shaft.
- A usually oil based
liquid, which provides cooling, reduces friction and resists contamination
and corrosion for ball bearings and related components.
similar surfaces by use of a magnetic field.
- Portion of the
bearing that contains the internal raceway for the balls.
- The ball or roller
path cut in the inner and outer ring in which the balls or rollers move.
Sometimes referred to as a guide path.
- A soft synthetic rubber
washer with a steel core fixed in the outer ring (in the seal groove)
in contact with the inner ring to retain lubricant and keep out contamination ( hydraulic seals).
- A thin metal plate or
washer used to pack or pre-load a bearing.
- Used to separate or
space bearings on the same or different rows in areas where multiple ball
bearings are used, such as in assembly lines.
- A load exerted
on a bearing not in motion.