At a ball-bearing it is a bearing in which rolling bodies are inserted between inner and outer rings to reduce frictional resistance. ball-bearing are mainly used as a fixation of shafts and axles, where they allow depending on the design of a radial or axial rotation of the shaft.

History of the ball bearing

Of the ball-bearing has a very rich history going back over 2700 years. At the end of the 20th century, a Celtic chariot was discovered during archaeological excavations, with cylindrical beech wood pieces near the wheel hubs. Because of this discovery, researchers and archaeologists assume that the Celts already around 700 BC. Chr. Have used a primitive shape of the cylindrical roller bearing to improve the rolling resistance of cars and carts. So were also in Rome towards the end of the Roman Empire ball-bearing used to build powerful hoists. The history of the modern ball bearing began in the wake of the Industrial Revolution in the second half of the 18th century. At the time of industrial change, there was a need for a bearing that performed better at lower speeds than traditional plain bearings. The plain bearings used up to then were not really useful at low speeds as they were wearing out very quickly. The forefather of the modern ball bearing is John Harrison. In 1759, the watchmaker invented a roller bearing with a cage, which he developed specially for a ship’s chronometer from his factory. Over the centuries, many new variants were added. There were major developments and innovations, especially in the areas of manufacturing accuracy and lubricant development. Numerous standards established common standard dimensions, greatly simplifying design and development. Nowadays there are sophisticated ones ball-bearing with integrated sensors with which z. B. can determine the degree of wear electronically.

Components of a modern ball bearing

Ball bearings are a subgroup of rolling bearings in which balls (rolling elements) are used to achieve optimum rolling resistance. In modern ball bearings cages are used, which serve to keep the rolling elements (balls, cones, cylinders) at an equal distance. Although ball bearings without a cage have proven to be less reliable, some special versions are still being produced without a cage. These are used primarily in control systems of aircraft. For rolling bearings without a cage, more rolling elements were used by bearing, which leads to a significant increase in load capacity. However, these are absolutely unsuitable for use at higher speeds. Cages were initially made of brass. Brass offered increased smoothness, which made ball bearings more and more popular and popular. Nowadays, cages are made of glass fiber reinforced plastic that has similar characteristics to brass, but which is much cheaper to produce.

Life of a ball bearing

The life of a ball bearing depends on many different factors. Some influencing factors such. B. bearing load can be calculated mathematically, while others such. B. Pollution or lubrication state can not be determined mathematically. For ball bearings, there are sometimes serious differences in quality, so that bearings for less demanding application scenarios such. B. in household appliances have an average life of a few hundred hours. On the other hand, there are again high-performance ball bearings, which have a high reliability and manufacturing quality and have an average life span of several hundreds of thousands of hours. These high-quality rolling bearings are mainly used in aviation and shipping.