4-Wire Race Bearings for High Performances

The 4-wire race technology, developed by Franke for its bearings, allows overall dimensions to be reduced while obtaining a smooth, accurate rolling. Today Franke’s bearing range, distributed by HTC in our country, also includes Direct Drive Bearings.

by Alma Castiglioni

Wire race bearings are the flagship of Franke’s bearing portfolio which also includes slim bearings, bearing assemblies and Direct Drive bearings, all of them distributed by HTC in our country. Bearing Elements are based on a simple, yet ingenious principle: individual race rings made of wire are fitted with a raceway designed precisely to match the diameter of the rolling elements.

Therefore, the rolling action does not take
place directly between the rolling elements and the mating structure, but rather with low friction on the four open race rings. The engineering principle permits free design of the mating structure in terms of geometry and material selection.
Available diameter from 80 mm up to 7 meters with several cross section for different purpose. Customized solution with stainless or anti magnetic steel are available in order to meet customers’ specific requirements.

Slim bearings: compact design and easy installation
Franke Slim Bearings are the logical development of the wire race bearing technology. Due to the special profile of the raceways with two contact points on each of the rolling elements, the 4-point-contact principle is maintained. The races are open and for serial request available in any desired section comprised between 4 and 8 mm, and any diameter from 90 to 700 mm. Installation and adjustment are just as easy as with conventional slim bearings with a large gain in load capacity. A great advantages compared with similar products is the cost effective.

Bearing assemblies: most diameters are available on short notice
Franke bearing assemblies are manufactured in standard sizes and they consist of an external structure with wire race bearing inside. The final product is a large diameter flanged bearing complete with fixing holes. They are available on short notice, in some cases even from stock. Bearing assemblies are available with external structures made of steel and aluminium, in the smooth version, in the steel version with straight teeth and in aluminium with toothed belt AT10 (other teeth are made to customer specifications). The aluminium versions offer the same characteristics as the steel versions with a significant reduction in weight and high corrosion resistance. This solution offers all the advantages of the bearing in elements as well as being ready for use. Thanks to their 4-point contact geometry, these bearings can withstand axial, radial and tilting loads; they offer high accuracy and smooth, even running at speeds up to 5 m/s. These bearings are available in diameters from 100 to 1800 mm, many of which are available on short notice.

Direct Drive bearings: the latest achievement
Direct Drive bearings are the latest product developed by Franke. The bearing structure is made of aluminium and houses bearing elements, magnets and motor windings and a magnetic stripe encoder (with incremental or absolute measuring system). The integration of the motor directly to the bearing, makes it possible to entirely dispense components such as gear and drive pinion. The Direct Drive bearing is ready for use, it simply requires an electrical connection to the steering unit. The advantages are many, starting from a drastic reduction in weight, space optimization with ample free central space, high dynamism and speed of rotation, integrated measurement system and, for particularly heavy applications, a liquid cooling system that allows power to be increased. Direct Drive units are available in diameters from 100 to 1800 mm and can be customised in terms of size according to requirements. An interesting application of this solution is represented by the CT scanners in the medical sector. Here, the requirements for speed and silence were met by designing a bearing with a diameter over one meter and an integrated motor. This allows speeds of 20 m/s to be achieved with a noise level below 60Db. Another added value of this product is the significant reduction in energy requirements due to the absence of friction generated by traditional transmission systems.