Rolling elements balls

Bearing balls are one of the main components of bearings used in various mechanisms to reduce friction between moving parts. They are the main load carriers in bearings and allow for rotational movement with minimal wear.

Bearing ball sizes

Bearing balls are available in a variety of sizes, depending on the intended use of the bearing as well as the required performance for a particular application.

Standard balls typically have a diameter of 1 mm to 100 mm. However, balls with a diameter of 3 mm to 50 mm are the most common.

The smallest bearing ball in the world was made of ceramic material and has a diameter of only 0.1 mm (100 microns). This is a real record, which was achieved thanks to the development of microtechnology and high-precision materials. A ball of this size is difficult to see without a powerful microscope.

Bearings for small machinery or precision instruments often use balls with diameters of 2 mm, 3 mm, 5 mm, while heavy industry can use balls with diameters of 25 mm and more.

The largest bearing ball known today is over 1.5 meters in diameter and made of steel. It was created for use in specialized bearings for giant machines and technical systems operating under enormous loads.

Tolerance

The size of the balls for bearings is also determined by their tolerance, i.e., the permissible deviation from the nominal diameter. For high-precision bearings, balls must have micron tolerances (P6, P5, P4).

Bearings with high-precision balls are used in complex mechanisms (high-speed machine tools, medical equipment and aircraft), where even the slightest deviations can lead to serious problems.

The bearing balls are manufactured to be perfectly round because even a slight curvature can affect their performance. In high-precision bearings, the roundness of the balls is measured at the micron level.

Materials of manufacture

- steel (chrome-plated) - the most common material for bearing balls, providing high strength, wear resistance and good performance at low and medium loads (usually AISI 52100 steel is used);

stainless steel - stainless steel balls are used in environments where corrosion resistance is required (in the food and pharmaceutical industries), as well as in conditions of high humidity;

ceramics - balls made of ceramics (aluminum oxide (Al2O3) or silicon carbide (SiC)) are used for bearings that must operate in extreme conditions, such as high temperatures or aggressive chemical environments (ceramics have a low coefficient of friction and greater rigidity compared to metal);

plastic - balls made of plastic are used for bearings that require high corrosion resistance, low weight, and low noise (in office equipment or moderate loads).

Load capacity

Bearing balls can withstand different levels of load depending on their material and size. They can withstand radial loads (when a force acts perpendicular to the axis of rotation) and axial loads (when a force acts along the axis of rotation).

For high-load bearings (in automobile engines or machine tools), large-diameter balls made of high-quality steel or ceramics are used.

The maximum load that a bearing ball can withstand can reach 200-300 kN for very large bearing balls in industrial applications. At the same time, most standard balls can withstand loads in the range of 10-50 kN, depending on the material and design of the bearing.

Balls can be arranged in one row (single row bearing) or in two rows. In double-row bearings, the load is distributed over two rows of balls, which increases the overall load capacity.

Lubrication

To reduce friction and extend the service life, the balls are often lubricated. Lubrication can be:

- liquid (oil),
- solid (mineral oils, graphite grease).

High-speed bearings can have ceramic or synthetic lubrication, which provides more stable operation at high temperatures and rotational speeds.

Types of coatings

To improve the corrosion resistance of bearing balls, steel balls are often coated with a special coating such as chrome plating or nickel plating.

Ceramic balls do not require additional coatings because they are naturally highly resistant to corrosion and wear.

Manufacturing accuracy

It determines how well the bearing ball conforms to the specified dimensions and shape. The higher the manufacturing accuracy, the greater the efficiency and durability of the bearing. Generally, balls are divided into several accuracy classes:

P0 - standard
P6 - medium
P5 and P4 - high-precision balls, used in the most precise and high-speed mechanisms.

Interesting things about the use of bearing balls

In computer hard drives (providing precise and smooth movement of the read head), these balls are so small and precise that many people do not even realize that they are in computer devices, although they are a critical component for their functioning.

In watches (in some high-end mechanical watches), bearing balls are used in mechanisms that provide high precision and durability. Such balls help the watch to work without problems for many years, even if the watch is on the wearer's wrist all day.

These facts show how diverse and important bearing balls are in our lives, even in areas where they are not always noticed.

On ebearing.com.ua you can find and buy bearing balls of various sizes and manufacturers.