What Is a Bearing?

The official technical definition of a bearing is a machine element that. Limits the relative motion between two parts to the motion specified in the overall design.Reduces friction between these moving parts. Next, the bearing supplier will share the following content with you.

A simpler definition can be found in the name “bearing”: a support structure designed to “carry” the stress or load of a given design.

While the typical use case for bearings is a shaft rotating in a shaft, they can be designed to facilitate many different desired ranges of motion. For example, linear bearings allow linear rather than rotary motion, with the bearing element moving along a rail or rod.

Printing Machine Bearings

The actual design of the components performing this function can vary widely. Bearings can be made from materials ranging from wood to brass to high grade polymers. Some bearing designs rely on frequent lubrication, while others operate in environments where lubrication is virtually impossible (such as space). Some bearings are designed to resist corrosion over long periods of submersion, while others are required to operate in the high temperatures of steel manufacturing plants.

Today, bearings are highly engineered components, built for highly specific applications, environmental hazards, maintenance requirements and price points.

Bearing Basics

In the typical case of a rotary bearing, the “journal” is the part of the shaft that is in contact with the bearing surface. In the simplest case, the bearing is not a discrete unit: the journal simply slides over the bearing surface, subject to any friction, heat, and wear that is generated. While they can be used in less demanding environments, bearing designs that do little to reduce friction will generate unacceptable amounts of heat and wear when used at the speeds and conditions required for demanding modern applications in industrial manufacturing, aerospace, and automotive.

Therefore, a pressing need in bearing design is to reduce friction to improve the performance characteristics and life of the bearing.

Several additional features can be added to reduce friction, starting with lubrication. Traditionally, this has been accomplished through initial and periodic injections of grease or oil. Today, some designs incorporate advanced lubricants embedded in the bearing material itself to reduce the need for manual lubrication. Other designs use low-friction materials that do not require lubrication at all under the correct operating conditions.

A second option is to add rolling design elements to reduce friction while maintaining the desired load-bearing characteristics. Based on this addition, bearing designs can be effectively divided into two advanced categories.

Sleeve/journal bearings vs. roller bearings

Ball/Roller Bearings

In these designs, the rolling element is placed between two sleeves: an inner sleeve in contact with the journal and an outer sleeve in contact with the bore. The “ball” is the most common form of rolling element, but it can also be a roller, gear or other design. The rolling element itself (usually metal) needs to be lubricated — either periodically or through a sealed bearing design.

Sleeve bearings (also called “journal” or “flat” bearings)

In this design, the journal simply slides on the bearing surface, without additional mechanical elements. The new low-friction, self-lubricating option allows plain bearings to be used in a variety of demanding applications that previously required rolling element designs.