Bearings
General information about bearings
Bearings are essential components in machinery and industrial applications. They provide efficient load transmission with minimal friction and help extend the life of moving parts. In this article, we discuss key aspects of bearings, including load, service life, bearing construction and common bearing types.
The load capacity
The primary function of bearings is to transfer load between a stationary part (such as a bearing housing) and rotating part (such as a shaft) with as little friction as possible.
Loads can arise from:
- The mass of the machine or parts
- The weight of the product to be moved
- The transmission of power
In rolling bearings, these loads are transmitted between the inner and outer rings through rolling elements.
The lifespan
The lifespan and proper functioning of bearings depends on a number of determining factors:
- the cleanliness, which therefore determines the quality of the bearing steel;
- the right amount of lubricant;
- the use and good seals of bearings;
- dimensional accuracy;
- RPM;
- load capacity;
- radial, internal clearance in the bearing;
- quietness;
- packing and storage in the warehouse.
In addition, there are external factors that affect longevity:
- the choice of bearing type and bearing arrangement;
- a clean working environment;
- correct mounting and dismounting of the bearings with special tools;
- precision machined shafts and housings;
- the right choice of shaft and housing fits;
- operating temperature;
- aftercare and maintenance;
- strong pollution from the outside and other operating conditions.
Structure of a bearing
A bearing usually consists of three main components:
- Two rings with raceways: The inner ring is connected to the rotating part, while the outer ring is attached to the structure.
- Rolling elements: Balls, rollers, or needles reduce friction between the rings.
- A cage: Keeps the rolling parts in place and prevents contact between the elements.
Rolling bearings are classified into ball bearings and roller bearings:
- Ball bearings have a point contact between the balls and the raceways.
- Roller bearings have a line contact, which makes them suitable for higher loads.
The most commonly used bearing in the world is the single-row deep groove ball bearing, available in various sizes and designs.
Bearing types
There are different types of bearings, each with specific properties and applications:
| Bearing type | Features |
|---|---|
| Single-row and double-row groove ball bearings | Universal use, suitable for high speeds |
| Single-row and double-row angular contact bearings | Offers high radial and axial load capacity |
| Two-row self-aligning ball bearings | Compensates misalignment, ideal for long shafts |
| Cylinder bearings | High radial load capacity and high rigidity |
| Tapered roller bearings | Suitable for combined loads |
| Spherical roller bearings | Self-adjusting, high load capacity |
| Axial ball bearings (thrust bearings) | Specific for axial loading |
When choosing a bearings, factors such as installation space, load capacity, speed and construction dimensions play a crucial role.
ISO Standard
Each bearing is designated by a code. Its characteristics are determined by a ISO standard. The ISO (International Standard Organization) has the task of developing and coordinating standards with the aim of international interchangebility of products. Strict application of this by bearing manufacturers ensures complete interchangeability of bearings, regardless of brand, with the same type number.
